EP4638076A1 - Positioning unit for a portable circular saw - Google Patents

Abstract

The invention relates to a positioning unit (20) for a portable circular saw (70), wherein the positioning unit (20) has a fastening portion (21) for exchangeably fastening the positioning unit (20) to a positive guide (10), in particular to a guide rail, and wherein the positioning unit (20) has, on an abutment side, a machine tool abutment, in particular a start position abutment (23.2) and/or an end position abutment (23.1), for limiting the movement of the portable circular saw (70) on the positive guide (10) in or counter to a guiding direction. The workpiece machining with the portable circular saw, in conjunction with the positive guide, is greatly simplified if provision is made that the positioning unit (20) has an add-on component interface (29), on which an add-on component (60) is fastened, preferably exchangeably fastenable.

Description

Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 Festool GmbH Wertstrasse 20 73240 Wendlingen am Neckar Positioning unit for a hand-held circular saw The invention relates to a positioning unit for a machine tool, in particular a hand-held circular saw, wherein the positioning unit has a fastening section in the area of a fastening side for the replaceable fastening of the positioning unit to a positive guide, in particular to a guide rail, and wherein the positioning unit has a machine tool stop on a stop side, in particular a start position stop and / or an end position stop for limiting the movement of the machine tool, in particular the hand-held circular saw, on the positive guide in or opposite to a guide direction. It can be the case, for example, that the fastening section of the positioning unit has a guide wall for guiding on a guide web of the positive guide. DE 10251578 B3 describes a guide rail for a hand-held circular saw on which a positioning unit in the form of a stop piece can be attached. The stop piece can be used to set the starting position of the hand-held circular saw for a planned saw cut. DE 102007007 841 B4 discloses a hand-held circular saw which has a saw blade driven by an electric motor. The saw blade is partially covered by a saw blade cover which prevents access to the cutting edge of the saw blade. A light element is attached to the saw blade cover. This can be used to illuminate the working area of the saw blade. US 7,185,998 discloses a hand-held drill which has a holder for a lamp on its handle. The lamp can be pivoted relative to the handle so that the Page 1 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 The light cone of the lamp can be precisely aligned with the work area of the drill. The object of the invention is to provide a positioning unit of the type mentioned at the outset, which significantly simplifies working with the machine tool, for example the hand-held circular saw, in conjunction with the forced guidance. This object is achieved in that the positioning unit has an additional component interface to which an additional component, in particular a lamp, is attached, preferably replaceably attachable. The positioning unit according to the invention can therefore be used to precisely set the start or end of a planned saw cut. Via the additional component interface, the user can make an additional component available directly in the work area of the machine tool, which makes his work easier. For example, he can attach a lamp to the positioning unit as an additional component. With this he can illuminate the work area of the machine tool. This means that, for example, the machine tool can be precisely aligned with respect to a workpiece together with the positive guide and a cut can be made precisely in a workpiece, in particular with a predetermined cutting length. The cutting result can be continuously monitored during the work process. It is also conceivable that instead of the lamp or in addition to it, another additional component is attached to the positioning unit, for example a chip catching device or an arrangement for the precise alignment of the positioning unit. In particular, if the additional component is interchangeably connected to the positioning unit, the user can make the appropriate work aid available as required. According to a preferred variant of the invention, it can be provided that the positioning unit has a boom that is coupled to the fastening section, for example is formed integrally with it, and that the boom has the additional component interface at its end area opposite the fastening section in order to position the additional component in the area of Page 2 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 a contact edge of the positive guide, in particular the guide rail. The contact edge of the positive guide is the area past which the hand-held circular saw is guided with its saw blade during the work process. This means that the additional component can advantageously be positioned directly in the working area of the hand-held circular saw. To ensure secure fastening of the additional component, it can be provided that it has a bearing part that carries a connecting section and that the connecting section is held on a holder of the additional component interface. The additional component can be attached to the bearing part. If it is provided that the additional component can be connected to the additional component interface in different positions and/or orientations by means of the connecting section, the orientation of the additional component on the positioning unit can be varied. This enables different installation positions. The user then has the option of aligning and positioning the additional component appropriately, depending on the spatial conditions. Preferably, the additional component can be adjusted transversely to the guide direction relative to the positioning unit. The user can then adjust the positioning of the additional component as appropriate depending on the spatial conditions. Advantageously, it can be provided that the connecting section of the additional component has at least one locking receptacle, by means of which the connecting section is attached to a counter-locking element of the additional component interface. This allows the additional component to be quickly attached to or removed from the positioning unit. Advantageously, a stepped locking connection is created between the additional component and the additional component interface, which makes it possible to connect the additional component to the additional component interface in several locking positions in order to implement the different mounting positions. This makes it possible to change the positioning of the additional component quickly and easily. Page 3 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 A preferred variant of the invention is such that a component carrier is used which is rotatably and/or pivotably connected to the bearing part by means of a bearing, and that the component carrier carries the additional component directly or indirectly, preferably interchangeably. According to a possible variant of the invention, it can be provided that a detachable force-fitting and/or material-locking connection is effective between the connecting section of the additional component and the additional component interface. This can be formed, for example, by an adhesive connection, a Velcro connection and/or a magnetic connection. In particular, it can be provided that the connecting section of the additional component has at least one magnet and the additional component interface has a counter magnet which interacts with the magnet of the connecting section and/or fixes the connecting section in at least one position relative to the additional component interface. According to the invention, it can be provided that the additional component has, for example, a lamp, a cutting width compensator, a laser cutting line indicator, or a chip collecting hood. If a chip collecting hood is used, it is advantageous if it is provided that it has a collecting body to which a discharge connection is coupled, wherein the discharge connection preferably has a change coupling element for connecting a dust extraction system. The chips caught in the chip collecting hood that accrue during processing can be removed in an orderly manner via the discharge connection. According to a variant of the invention, it can be provided that the cutting width compensator has a marking edge on at least one attachment and that the attachment is coupled directly or indirectly via a component carrier to the connecting section. The cutting width compensation can be carried out in a way that is easy for a user to see, in order to take the cutting width of the saw blade into account before the work process. Page 4 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 The marking edge preferably extends parallel to the guide direction and/or parallel to a guide wall of the fastening section. A particularly simple and precise adjustment can be achieved if it is provided that the at least one cutting width compensator can be adjusted via a sliding guide relative to the positioning unit, preferably continuously and/or without tools, wherein the adjustment direction of the sliding guide preferably runs transversely to the feed direction of the hand-held circular saw, i.e. in the guide direction. One possible variant of the invention can be such that a cutting length adjustment element, preferably adjustable, is attached to a carrier or the additional component interface, wherein the cutting length adjustment element is held in the region of the fastening section or the/an extension of the positioning unit, and that the cutting length adjustment element protrudes beyond the fastening section in or opposite to the guide direction. This has particular advantages, for example, when a plunge cut is to be made in a workpiece using a plunge saw. As already described above, the positioning unit has the machine tool stop on the stop side, in particular the starting position stop, for limiting the movement of the machine tool on the forced guide opposite to a guide direction. A positioning unit designed in this way can therefore be used to precisely set the start of a planned saw cut. This has particular advantages, for example, when a plunge cut, for example a concealed one, is to be made in a workpiece using a plunge saw (safely). The start of the cut is determined by the starting position stop. In a preferred variant of the invention, it can also be provided that the positioning unit according to the invention is used to precisely set the end of a planned saw cut. The end of the cut can then Page 5 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 advantageously be determined by the machine tool stop, which then forms an end position stop. For example, it can be the case that the start of the cut is determined by the machine tool stop (start position stop). At the start of a planned machining operation, the positive guide/guide rail is placed on the workpiece to be machined. The positioning unit can then be connected to the positive guide/guide rail. The planned cutting depth is then set on the cutting length adjustment element. The marking on the cutting length adjustment element corresponding to the planned cutting depth is then aligned with a marking on the workpiece that represents the planned start of the cut. The hand-held circular saw can now be placed on the positive guide/guide rail and moved against the planned machining direction. This movement is limited with the machine tool stop (start position stop) of the positioning unit. A corresponding counter stop of the hand-held circular saw hits this. The hand-held circular saw is now positioned exactly so that the saw cut can be made. Because the counter stop of the hand-held circular saw rests against the machine tool stop at the start of workpiece processing, this prevents the hand-held circular saw from moving backwards (and possibly upwards) in an uncontrolled manner against the planned processing direction when engaging the workpiece. This ensures the quality of the cut made and also reduces the risk of injury to the user. In the same way, a positioning unit according to the invention can also be used to limit or precisely adjust the planned end of the cut. It is advantageous to calibrate the positioning unit before starting planned processing of the workpiece to be processed. To do this, the positive guide/guide rail is placed on a test workpiece at the start of the calibration. The positioning unit is then placed on the positive guide/guide rail, placed with the machine tool stop on the counter stop of the hand-held circular saw and then secured to the positive guide/guide rail. A test cut is then made with the hand-held circular saw. Page 6 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 A cut, in particular a plunge cut, is made in a test workpiece which has a rear and a front end. Optionally, the hand-held circular saw can now be removed from the positive guide/guide rail. The cutting length adjustment element is then adjusted relative to the machine tool stop with the position fixed relative to the test workpiece so that a marking, advantageously a marking corresponding to the planned cutting depth, of the cutting length adjustment element is aligned with the rear or front end of the test cut, depending on whether the positioning unit was arranged behind or in front of the hand-held circular saw in the machining direction. It is conceivable that the carrier to which the cutting length adjustment element is adjustably attached and/or the cutting length adjustment element is/are interchangeably connected to the positioning unit. This allows different supports, each designed to be adapted to the dimensions of a saw blade and/or a specific hand-held circular saw, to be attached to the positioning unit. A user therefore has the option of using different saw blades on his hand-held circular saw and/or different machine types on a positioning unit. Depending on the geometry of the saw blade, he then selects the appropriate support and connects it to the positioning unit. Additionally or alternatively, the cutting length adjustment element can also be connected to the support in an interchangeable manner. The cutting length adjustment element suitable for a specific hand-held circular saw type and/or saw blade can thus be selected and connected to the support and/or the positioning unit. In other words, the user has the option of using a predetermined cutting length limiting device with different hand-held circular saws and/or different saw blades. According to a preferred embodiment of the invention, it can be provided that the positioning unit has a kick-back stop for a counter stop of the hand-held circular saw. A kick-back stop is characterized by the fact that it prevents the machine tool from being lifted in the direction opposite to the workpiece surface (for example, in the direction opposite to the attachment side of the Page 7 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 fastening section in the opposite direction). In conjunction with the machine tool stop, the kick-back stop ensures that the hand-held circular saw is securely fixed. This ensures, in particular, that a plunge cut can be made reliably in a workpiece. In particular, the critical plunging process is safeguarded. After the hand-held circular saw has been moved into its plunging position, it can be adjusted in the guide direction and the planned saw cut can be made in the workpiece. The machine tool is then moved out of the effective range of the kick-back stop. Within the scope of the invention, the counter stop of the machine tool can be fixed in a form-fitting and/or force-fitting manner relative to the positioning unit by means of the kick-back stop. According to a preferred variant of the invention, it can be provided that the kick-back stop has a height stop which is arranged at a distance from the fastening side and is oriented towards it, forming a distance area. In this way, the counter stop of the machine tool can be moved into the area between the fastening side and the height stop and reliably positioned there. The height stop overlaps the counter stop of the machine tool in a form-fitting manner. This achieves a form-fitting connection in the direction opposite to the top of the workpiece to be machined between the positioning unit and the hand-held circular saw. One conceivable variant of the invention is such that the kick-back stop is arranged in the area of the starting position stop, wherein it is preferably provided that the starting position stop is arranged in the area of the distance space below the height stop. This achieves an optimized flow of force and a compact structural assignment of the starting position stop to the kick-back stop. According to a variant of the invention, it can be provided that the fastening section carries a clamping element which is arranged in the area of the page 8 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 fastening side and adjustable between a release position and a clamping position, that the fastening section has at least one recess open towards the fastening side, and that the clamping element engages at least partially in the recess in the clamping position and releases an engagement area of the recess in the release position. Usually, forced guides, preferably guide rails, are equipped with a rib-shaped projection running in the guide direction, which forms an undercut guide groove. The positioning unit can now be placed with its downwardly open recess, transversely to the longitudinal extension of the undercut groove, over the rib-shaped projection, with the clamping element then immersing itself in the undercut groove. The fastening section can now be fixed relative to the guide rail by adjusting the clamping element from the release position to the clamping position. The clamping element is clamped in the undercut groove. In this design variant, the positioning unit with its fastening section can be placed on the forced guide/guide rail at any position and fixed to it. It is therefore not necessary for the fastening section to be laboriously threaded from the front side of the undercut groove. In such an inventive variant, it can also be provided in particular that the clamping element has a base part, wherein the base part has a receptacle to which a handle is coupled for adjusting the clamping element, and wherein the base part has arms on diametrically opposite sides. An attachment for limiting the adjustment of the clamping element can be arranged on at least one of the arms, wherein each of the attachments has at least one arm stop. The clamping element can be clamped via the two arms, driven by the handle, with clamping surfaces arranged on the arms on opposite sides of the undercut groove. This creates a particularly resilient clamping connection. A cutting length limiting device according to the invention can be such that the fastening section of the positioning unit has a receptacle to which a Page 9 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 clamping element is held in place, that the clamping element carries a clamping piece on a lever at a distance from a support part, and that a/the handle, for example a rotary knob, is adjustable relative to the support part in order to move the clamping piece from a release position to a clamping position. This measure can also be used to reliably fasten the positioning unit to the positive guide/guide rail. The fastening is particularly effective if the clamping element is used in addition to the clamping element mentioned above, which is clamped in the undercut groove. It is particularly advantageous if the handle is used to clamp both the clamping element and the clamping element. This enables user-friendly fastening of the positioning unit. If it is provided that the clamping element held on the fastening section has an alignment element, which preferably has an alignment bevel, wherein the alignment bevel extends in the guide direction of the positive guide and in the clamping position of the clamping element is at an angle of less than 90° to the fastening side of the positioning unit, then the positioning unit can be aligned precisely relative to the positive guide/guide rail. In this case, the alignment bevel rests against a body edge extending in the guide direction of the positive guide/guide rail. As a result, the clamping element and thus the entire positioning unit are aligned precisely with the positive guide/guide rail. The body edge is preferably formed by the projection mentioned above, which forms the undercut groove. In order to simplify the adjustment process of the cutting length limiting device even in places where visibility is difficult, it can be provided that the positioning unit has an arm which has a further carrier at a distance from the fastening section and/or the carrier, and that the two carriers each carry a cutting length adjustment element. In particular, it can be the case that the cutting length adjustment elements are arranged on the opposite sides of the positioning unit running in the guide direction and thus on the long sides of the guide rail. With such an arrangement, even if the saw blade is close to the wall during processing Page 10 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 is arranged, on the opposite side the cutting length adjustment element can be aligned with a mark on the workpiece. Preferably, the two cutting length adjustment elements can be interchangeably attached to the supports. Additionally or alternatively, it can also be provided that one or both supports are interchangeably attached to the positioning unit, in particular without tools. Preferably, it can also be provided that both cutting length adjustment elements and/or both supports are of identical construction so that identical parts can be used. A particularly precise alignment of the positioning unit can be achieved if it is provided that the support(s) has/have a guide on which the cutting length adjustment element is adjustably held with a guide section, and that the cutting length adjustment element can be adjusted in and/or opposite to the guide direction by means of an adjusting element on the guide, preferably continuously. According to the invention, the cutting length adjustment element can also have markings, for example in the form of a scale, which represent adjustable cutting depths of the hand-held circular saw. The user can determine the cutting depth set on the hand-held circular saw and then align the corresponding cutting depth marking on the cutting length adjustment element with a scribe mark on a test workpiece. He can then make a test cut in the test workpiece with the hand-held circular saw. If the start of the cut does not match the scribe mark, the user can make a correction to the adjustment element and thus adjust the cutting length adjustment element accordingly. In this way, for example, changes in the diameter of the saw blade as a result of resharpening processes or wear can be compensated. Page 11 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 It can preferably be provided that the scale is applied to an underside of the cutting length adjustment element facing a workpiece to be machined and that the scale is arranged in an area of the cutting length adjustment element which is formed from a transparent material. This can minimize parallax errors. A particularly simple and reliable design results if it is provided that a threaded section, preferably in one piece, is coupled to the guide section of the cutting length adjustment element, which together with a thread of the adjusting element forms an adjusting gear for continuously adjusting the cutting length adjustment element in and/or opposite to the guide direction, wherein it is preferably provided that the cutting length adjustment element has a scale. As mentioned above, the scale can be such that it marks different cutting depth settings that can correlate with cutting depth markings on the machine tool used. A possible variant of the invention can be such that the carrier and/or the cutting length adjustment element has a sacrificial section that is designed and prepared to protrude into the sawing area of the hand-held circular saw, such that a saw blade of the hand-held circular saw cuts out a sawn-in area from the sacrificial area, wherein it is preferably provided that the sacrificial section is integrally formed on the carrier and/or the cutting length adjustment element. With such a configuration, the positioning unit can be precisely adjusted for a predetermined cutting depth and a saw blade mounted on the hand-held circular saw. To do this, a test cut is first produced in a workpiece, in particular a test workpiece, wherein the sacrificial section is sawn in with the predetermined cutting depth infeed. In this way, the beginning of the sawn-in area exactly reflects the beginning of the cut. Now the beginning of the sawn-in area can be aligned with a scribe mark on a workpiece to be machined. Then, in the subsequent saw cut, the beginning of the cut can be made exactly at the specified point in the workpiece to be machined. It is advantageous that the remaining, not Page 12 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 The sawn-in area of the sacrificial section also acts as a splinter guard if it is arranged so that it sits on the top of the workpiece. It is also conceivable for the user to align the marking on the cutting length adjustment element corresponding to the set cutting depth with the beginning of the sawn-in area of the sacrificial section. In this way, the exact markings on the cutting length adjustment element can now also be aligned with a crack in the workpiece for other cutting depths. In other words, the sawn-in area provides a precise calibration mark to which the cutting length adjustment element can be aligned. If the sacrificial section is molded onto the carrier in one piece, it is easy to manufacture, for example as a plastic injection-molded part. A stable fastening of the positioning unit to a guide rail is achieved in a simple manner if it is provided that a guide carrier is connected to the fastening section, which has a recessed, preferably groove-shaped, linear guide receptacle, wherein the linear guide receptacle is arranged at a distance from an engagement section formed by the fastening section and designed in the form of a protruding projection. The object of the invention is also achieved with a guide assembly for a hand-held circular saw with a positioning unit according to one of claims 1 to 16 and a positive guide in the form of a guide rail, wherein the guide rail has a guide groove running in the guide direction and/or a guide web running in the guide direction, wherein the guide rail forms a fastening long side running in the guide direction and opposite a cutting edge side with a contact edge, wherein the positioning unit with the fastening section is detachably connected to the guide rail in the area of the fastening long side, and that the additional component is held at least in part laterally next to the contact edge in the area of the cutting edge side. Page 13 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 If it is intended that a rear positioning unit and a further positioning unit are arranged at a distance from it in the guide direction, whereby both positioning units preferably have an additional component interface, then the user can attach the additional component to both or optionally to the interface that is suitable for him. The invention is explained in more detail below with reference to embodiments shown in the drawings. Shown are: Fig.1: a structural unit with a forced guide and a front and a rear cutting length limiting device in plan view, Fig.2: another design variant of a cutting length limiting device for the front and rear limitation of a cut in plan view, Fig.3: a detailed view in perspective view from behind of the cutting length limiting device according to Fig.1 with an inclined hand-held circular saw, Fig.4: a machine unit according to Fig.3 in perspective view from the front, Fig.5: a detailed perspective view of the assembly according to Fig.1, Fig.6: the representation according to Fig.5 without handle, Fig.7: a sectional view transverse to the processing direction through the assembly according to Fig.5, Figs.8 and 9: a section of a positioning unit of the assembly according to Fig.1 in a view from below in various operating positions, Fig.10: a clamping element in perspective view, Page 14 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 Fig.11: a detailed view of a positioning unit, Fig.12 to 14: various additional components for attachment to the positioning unit according to Figure 11, Fig.15 an alternative design variant of a positioning unit in a view from below Figure 16 the positioning unit according to Figure 15 from above, Figure 17 another design variant of a positioning unit with an additional component in a perspective view, Figure 18 the additional component according to Figure 17 in an enlarged view, Figure 19 the positioning unit according to Figure 17 in a schematic assignment to a workpiece in a view from above and in a first operating position, Figure 20 a detail marked in Figure 19 in an enlarged view, Figure 21 the positioning unit according to Figure 17 in a schematic assignment to a workpiece in a view from above and in a second operating position, Figure 22 a detail marked in Figure 21 in an enlarged view, Figure 23 the positioning unit according to Figure 17 in a schematic assignment to a workpiece in a view from above and in a third operating position, Figure 24 a detail marked in Figure 23 in an enlarged view, Figure 25 a further design variant of a positioning unit with an additional component in a perspective view, Page 15 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 Figure 26 the additional component according to Figure 25 in an enlarged view, Figure 27 the additional component according to Figure 26 in an exploded view, Figure 28 the positioning unit according to Figure 25 in a schematic assignment to a workpiece in a view from above and in a first operating position, Figure 29 the positioning unit according to Figure 25 in a schematic assignment to a workpiece in a view from above and in a second operating position, Figure 30 a detail marked in Figure 29 in an enlarged view, Figure 31 the positioning unit according to Figure 25 in a schematic assignment to a workpiece in a view from above and in a third operating position, Figure 32 a detail marked in Figure 31 in an enlarged view Figure 33 the positioning unit according to Figure 17 with a changed assignment of the additional component, Figures 34a a further design variant with a positioning unit to which an additional component with a Cutting length adjustment element is assigned, Figure 34b the arrangement according to Figure 34a in a changed assembly position, Figure 35 the additional component according to Figures 34a and 34b in an enlarged individual view, Figures 36 and 37 each show an enlarged detail of the positioning unit according to Figures 34a/34b and Page 16 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 Figures 38 and 39 show enlarged detailed views of the installation situations of the positioning unit according to Figures 34a/34b, whereby an error prevention mechanism is also illustrated here (Poka-Yoke principle). Figure 1 shows an assembly for use with a hand-held circular saw 70. The hand-held circular saw 70 can be designed in particular as a plunge saw or as a pendulum hood saw. The assembly has a positive guide 10, which is designed in the form of a guide rail. The assembly also has a cutting length limiting device with a positioning unit 20. The guide rail has (see Figure 5) a lower support surface 15 for resting on a workpiece and an upper guide side 14 opposite. The hand-held circular saw 70 (see Figures 3 and 4) can be placed on guide surfaces of the guide side 14 and guided in the direction of the longitudinal extension of the guide rail. To force the hand-held circular saw 70, the guide rail has an upwardly open guide groove 11 which extends in the direction of the longitudinal extension of the guide rail and which is designed as an undercut groove. The guide rail also has a guide web 12 parallel and spaced apart from the guide groove 11. The guide web 12 is designed as a rib-shaped projection which protrudes over the guide side 14 and which also extends in the direction of the longitudinal extension of the guide rail. As Figure 1 further illustrates, at least one positioning unit 20 can be attached to the top of the guide rail. The positioning unit 20 shown on the left in Figure 1 serves to limit the start of a planned saw cut. The positioning unit 20 shown on the right in Figure 1 serves to limit the end of the planned cut. Page 17 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 The left-side positioning unit 20 is first explained in more detail below. As Figure 1 illustrates, the positioning unit 20 has a fastening section 21. The fastening section 21 is designed to be fixedly attached to the guide rail. In this case, the fastening section 21 can be detachably connected to the guide groove 11 and/or the guide web 12. As Figure 5 illustrates, an engagement section 21.3 on the fastening section 21 can be used to attach the positioning unit 20 to the guide groove 11, which engages in the guide groove 11. Recesses 21.1, 21.2 can preferably be provided on both sides of the engagement section 21.3. The recesses 21.1, 21.2 accommodate the groove walls protruding over the guide side 14 of the guide rail. To fix the fastening section 21 to the guide groove 11 and thus to the positive guide 10, a clamping mechanism can be used which produces a clamping connection at any position in the direction of the longitudinal extension of the guide groove 11. The clamping mechanism is preferably carried by the fastening section 21 of the positioning unit 20. The clamping mechanism can, for example, have a clamping element 50 and/or a clamping element 80 by means of which a clamping connection is produced with the guide rail. As Figures 5-7 show, the clamping element 50 can carry a clamping piece 55 on a lever 54, wherein the clamping piece 55 rests on a clamping surface to form a counter bearing in order to form the clamping connection, so that the clamping element 80 can be clamped to the guide rail. It can be provided that the clamping element 50 is adjustably accommodated in a receptacle 21.5 of the fastening section. It can be provided that a support part 53 is connected to the lever 54. The clamping element 50 can have lateral projections 56 which are arranged on opposite sides 18 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 sides of the support part 53 and which are adjustably received in the area of the receptacle 21.5 of the fastening section 21, for example to form a sliding seat or a pivot bearing. An alignment element 51 can preferably be provided on the clamping element 50. The alignment element 51 is designed and prepared to work together with a counter surface, the guide rail. The counter surface preferably runs in the direction of the longitudinal extension of the guide rail. The clamping element can thus be precisely aligned with the alignment element 51 relative to the counter surface when it is in its clamping position, as shown in Figure 7. In this way, the clamping element and thus also the entire positioning unit 20 are aligned relative to the guide rail. In one design variant, the alignment element 51 of the clamping element 50 can have an alignment surface that extends in the direction of the longitudinal extension of the guide rail and that is at an angle of less than 90° with respect to the underside support surface 15 of the guide rail. In this way, the clamping element 50 aligns itself with respect to the counter surface of the guide rail during the clamping process. Figure 7 illustrates that the alignment element 51 can be formed by legs 52 that are coupled to the support part 53, for example via the lugs 56, wherein the legs 52 extend in the direction of the support surface 15 and are arranged at a distance from one another. In the assembled state, the legs 52 at least partially overlap a lateral boundary edge of the guide rail and/or at least one groove wall of the guide groove 11. The above-mentioned alignment surface of the clamping element 50 can be formed by the alignment element 51 and/or the legs 52. Figure 6 illustrates that the clamping element 50 can have an opening 53.1, preferably in the area of the support part 53. A handle 30, here designed as a rotary knob (see Figure 5), is arranged in the area of the top of the clamping element 50. This handle 30 can be directly or indirectly attached to the page 19 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 Top of the support part 53. A threaded section 31 of the handle 30 passes through the opening 53.1, with the threaded section 31 being screwed into a threaded receptacle below the support part 53. In this way, by turning the handle 30, the threaded section 31 can be screwed into the counter thread. The handle 30 then presses on the support part 53, so that the clamping element 50 with its clamping piece 55 and/or alignment element 51 is pressed onto the top of the guide rail and the positioning unit 20 is thus fixed relative to the guide rail. Additionally or alternatively, it can be provided that the positioning unit 20 can be detachably connected to the guide rail in the region of its fastening section 21 with a clamping element 80. The clamping element 80 is shown in Figures 8, 9 and 10. As this illustration illustrates, the clamping element 80 is arranged in the area of the underside, i.e. the side of the fastening section 21 facing the support surface 15, and can be adjusted between the clamping position shown in Figure 8 and the release position shown in Figure 9. Preferably, the clamping element 80 can be adjusted by means of the handle(s) 30. The clamping element 80 can be designed such that it has one or more clamping surfaces 88 which serve to clamp the clamping element 80 in the clamping position in the guide groove 11. In the present exemplary embodiment, the clamping element 80 has clamping surfaces 88 on opposite sides, by means of which it can be clamped on the opposite, mutually facing inner side surfaces of the guide groove 11. Figure 10A shows a possible design of a clamping element 80. As this illustration illustrates, the clamping element 80 has a base part 81. Arms 82 can be formed on opposite sides of this base part 81. The two arms 82 form the clamping surfaces 88, whereby the clamping surfaces 88 are preferably arranged on one side surface of the arms 82. Page 20 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 The clamping element 80 may have a projection 85 with a receptacle 84 in the area of its base part 81. The receptacle 84 can, for example, be designed as a threaded receptacle for the threaded section 31. Preferably, the threaded section 31 is screwed into the receptacle 84 with the interposition of a friction element 89. For example, the friction element can be formed by a thread lock, for example a plastic layer. As Figures 10A, 10B show, the friction element can be introduced into a groove in the receptacle 84 of the clamping element 80 or a groove in the threaded section 31 of the handle 30. As Figure 10A shows, the clamping element 80 has an arm stop 87 on one stop side on each of its arms 82 and a bevel 83 opposite on the clamping side. As Figures 8 and 9 show, the clamping element 80 can be inserted into the fastening section 21 from the underside. For this purpose, the fastening section 21 has a clamping element receptacle that is open at the bottom and can be arranged between two engagement sections 21.3, for example an engagement section 21.3 at the front in the machining direction and an engagement section 21.3 at the rear in the machining direction. The clamping element 80 is rotatably mounted with its projection 85 in the clamping element receptacle. The axis of rotation preferably runs perpendicular to the guide side 14 of the guide rail. To attach the clamping element 80 to the positioning unit 20, the threaded section 31 of the handle 30 is screwed into the receptacle 84. Figure 8 shows the clamping position of the clamping element 80. In the clamping position, the clamping surfaces 88 are placed on the opposite inner sides of the guide groove 11 when the positioning unit 20 is placed on the guide rail. The required clamping pressure is applied via the handle 30, which is screwed into the holder 84 with its threaded section 31. Page 21 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 The bevels 83 mentioned above ensure that the clamping element 80 in the clamping position does not rest in the transition area of the guide groove 11, which is formed between the bottom of the guide groove 11 and the inner sides of the guide groove 11. Figure 9 shows the starting position of the clamping element 80, with the clamping element 80 in its pivoted-in position. In this position, the arm stops 87 of the clamping element 80 rest on stops 21.6, which the fastening section 21 forms in the area of the clamping element holder. The stops 21.6 are aligned such that the clamping element 80 is aligned in the direction of the two engagement sections 21.3 and does not protrude into the recesses 21.1, 21.2 or does not protrude in such a way that insertion of the clamping element 80 into the guide groove 11 in the direction perpendicular to the guide side 14 is hindered. This ensures that the positioning unit 20 can be placed on the guide rail in any position in the direction of the longitudinal extension of the guide rail and does not have to be laboriously threaded into the guide groove 11 at the front. Accordingly, the positioning unit 20 can be placed on the guide rail at the desired position, with the clamping element 80 and the engagement sections 21.3 protruding into the guide groove 11. The handle 30 can then be adjusted and thus both the clamping piece 55 can be tensioned and the clamping element 80 can be moved from the rest position shown in Figure 9 to the clamping position shown in Figure 8. In this way, the positioning unit 20 is reliably and aligned connected to the guide rail. If the clamping position is released, the positioning unit 20 can be moved relative to the positive guide 10 in the direction of the longitudinal extension of the positive guide 10 and thus in a direction parallel to the guide direction of the hand-held circular saw. The longitudinal extension of the fastening section 21 thus also runs in or parallel to the guide direction. The positioning unit 20 is guided on the positive guide 10 by means of at least one guide wall (in Figure 5 at reference number 22) of the positioning unit 20, which extends in the guide direction and is guided, for example, on the guide web 12. Page 22 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 The aforementioned friction element 89, which is provided between the threaded section 31 and the receptacle 84 of the clamping element 80, ensures that the clamping element 80 can be pivoted from the rest position according to Figure 9 into the clamping position according to Figure 8, and that only then is it possible to tighten the threaded connection in an operationally safe manner. Figures 1 and 7 illustrate that the positioning unit 20, preferably in the area of the fastening section 21, can have a linear guide receptacle 22 which is incorporated into the positioning unit 20 in the form of a downwardly open groove. The cross-sectional design of the linear guide receptacle 22 is adapted to the cross-sectional design of the guide web 12. Figures 5 and 6 illustrate that the linear guide receptacle 22 receives the guide web 12 in the assembly position, so that the positioning unit 20 is also aligned with respect to the guide rail. Preferably, both the linear guide receptacle 22 and the clamping element 80 and/or the tensioning element 50 are arranged on a guide support 23 of the positioning unit 20. A boom 24 can be connected to the guide support 23, which is guided from the fastening side of the guide rail to a contact edge 13 of the guide rail opposite the fastening side, as illustrated in Figure 1. Figure 5 shows that the fastening section 21 can have a holder 21.4. The holder 21.4 serves to receive a carrier 25. The carrier 25 is preferably held laterally next to the fastening side of the guide rail. The carrier 25 can be integrally connected to the holder 21.4 or preferably detachably connected to it. The carrier 25 carries a cutting length adjustment element 40. The cutting length adjustment element 40 may have a guide section 43 which is guided on a guide 27 of the carrier 25 in the direction of the longitudinal extension of the guide rail. Page 23 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 An adjustment element 26 can be provided on the carrier 25 for adjusting the cutting length adjustment element 40. A gear can be effective between the adjustment element 26 and the cutting length adjustment element 40, by means of which a continuous adjustment of the cutting length adjustment element 40 in the direction of the longitudinal extension of the guide rail relative to the carrier 25 is enabled. In this case, it is conceivable that the carrier 25 has an adjustment element receptacle 26.1 (see also Figure 8) with a thread. The cutting length adjustment element 40 has a threaded section 44 which cooperates with this thread to form the gear. The adjustment element 26 can, as in the present case, have a handle part which is arranged on the carrier 25 in an easily accessible manner in order to enable a user to operate it. By turning the adjusting element 26, the cutting length adjustment element 40 can be adjusted in the direction of the longitudinal extension of the guide rail. Figure 8 illustrates that the carrier 25 can have a window-shaped opening into which a stop of the carrier 25 projects. The adjustment movement of the cutting length adjustment element 40 is limited at the longitudinal ends of the opening. Figure 1 shows that the cutting length adjustment element 40 can have a scale 42 on which various cutting depth settings are marked. These cutting depth settings correlate with cutting depth settings that are indicated on a setting scale of the hand-held circular saw 70 used. The type of hand-held circular saw 70 can be marked on the cutting length adjustment element 40, as shown above. By way of example, it is stated here in the exemplary embodiment that the cutting length adjustment element 40 correlates with the hand-held circular saw of the type "TS 60" (or "XX-XX" in Figures 38, 39). It is preferable that the cutting length adjustment element 40 consists of a transparent material at least in the area of the scale 42, and that the scale 42, similar to a set square, is applied to the underside of the side of the cutting length adjustment element 40 facing the workpiece in order to Page 24 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 to minimize parallax errors. Alternatively, a cutting length adjustment element 40, for example one that is not transparent, can have a scale printed on the top. A support element 41 can be provided at the long end of the cutting length adjustment element. This support element 41 serves to support the cutting length adjustment element 40 on the top of a workpiece to be machined. The cutting length adjustment element 40 can be designed such that it can be interchangeably connected to the carrier 25. This ensures that the positioning unit 20 can be used in conjunction with different types of hand-held circular saws 70. Additionally or alternatively, it can also be provided for this purpose that the carrier 25 can be interchangeably connected to the fastening section 21. Figure 1 further illustrates that the holder 21.4 can be arranged on the boom 24 of the positioning unit 20. The holder 21.4 arranged on the boom 24 can advantageously be a further holder 21.4 (to the holder arranged on the fastening section 21). The further holder 21.4 accommodates a further carrier 25 which holds a further cutting length adjustment element 40 to the side of the contact edge 13 of the guide rail. Advantageously, the additional holder 21.4 is identical in construction to the holder 21.4 and/or the additional carrier 25 is identical in construction to the carrier 25 and/or the additional cutting length adjustment element 40 is identical in construction to the cutting length adjustment element 40. Preferably, the carrier 25 has a fastening interface that allows the carrier 25 to be attached both to the holder 21.4 of the fastening section 21 and to the holder 21.4 of the boom 24. A user can then optionally attach a carrier 25 with a cutting length adjustment element 40 to the fastening side and/or to the side of the contact edge 13. In this way, the user can choose the arrangement that is most suitable for him. Page 25 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 If the supports 25 are constructed identically, identical parts can be used. It is also preferred that the cutting length adjustment elements 40 are essentially designed as identical parts. Furthermore, it is conceivable that a cutting length adjustment element 40 can only be used on the side of the contact edge 13. Figure 1 further shows that the positioning units 20 each have a machine tool stop for a hand-held circular saw 70. The machine tool stops are preferably arranged in the area of the fastening section 21 and more preferably in an area formed between the guide groove 11 and the guide web 12 in order to enable stable assignment to the guide rail. The machine tool stop of the left-hand positioning unit forms a start position stop 23.2 for limiting the movement of the machine tool on the positive guide 10 opposite to a guide direction. The machine tool stop of the right-hand positioning unit forms an end position stop 23.1 for limiting the movement of the machine tool on the positive guide 10 in the guide direction. Furthermore, a kick-back stop 28 can be provided, which is preferably arranged in the area of the fastening section 21 and which is more preferably assigned to the starting position stop 23.2. The kick-back stop 28 is advantageously arranged above the starting position stop 23.2. The kick-back stop 28 has an overlapping section which is held at a distance from an underside of the positioning unit 20 and/or the guide side 14 of the guide rail in order to form a receiving section. A counter stop of the hand-held circular saw 70 used can be inserted into this receiving section. The counter stop engages under the kick-back stop 28 when the hand-held circular saw 70 rests against the starting position stop 23.2. Page 26 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 Figures 3 and 4 illustrate that the hand-held circular saw 70 can have a conventional design. For example, the hand-held circular saw 70 can have a base plate 71 with which it is placed on the guide rail. The base plate 71 is designed such that it is guided both on the guide groove 11 and on the guide web 12 and is thus slidably guided on the guide side 14. In this way, the hand-held circular saw 70 can be moved in the direction of the longitudinal extension of the guide rail by means of the base plate 71. A pivot assembly 74 of the hand-held circular saw is pivotally mounted on the base plate 71 by means of a pivot bearing 72. The pivot axis of the pivot bearing 72 runs parallel to the longitudinal extension of the guide rail. To fix the swivel assembly 74, the swivel bearing 72 has a toggle 73 which fixes the swivel assembly 74 in the desired swivel position. The drawings according to Figures 3 and 4 also show that the swivel assembly 74 has a saw blade cover 75, behind which a saw blade S of the hand-held circular saw 70 is housed in a protected manner. The saw blade cover 75 has a side that is open at the bottom as usual, through which the saw blade S can be swiveled into its plunge position. The saw blade cover 75 can be provided with an extraction connection 76 for a clamping suction device. To precisely set the start of the planned saw cut, the cutting depth set on the hand-held circular saw 70 can be read off an adjustment scale. A correlating value for this read value can be found on the scale 42 of the cutting length adjustment element 40. This correlating value is then aligned with a mark on the workpiece to be machined. The marking indicates the planned start of the cut. If the cutting length limiting device is aligned with this marking, it can be locked to the guide rail using the handle 30. As mentioned above, the hand-held circular saw 70 can be positioned on the positioning unit 20 shown on the left in Figure 1 to make the planned saw cut. Page 27 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 The hand-held circular saw 70 rests with the base plate 71 on the start position stop 23.2 of the positioning unit 20. The kick-back stop 28 engages over a counter stop on the base plate 71 of the hand-held circular saw 70. The hand-held circular saw 70 can now be activated. The pivot assembly 74 of the hand-held circular saw 70 is then pivoted about a pivot axis running transversely to the guide rail, namely by the amount of the planned cutting depth. The saw blade S cuts into the workpiece, whereby the start of the planned saw cut then results in the plunge position, which is congruent with the scribe mark on the workpiece to be machined. The hand-held circular saw 70 can then be moved in the guide direction in order to completely insert the planned saw cut into the workpiece. The guide direction runs from left to right in Figure 1. The starting position stop 23.2 prevents the hand-held circular saw 70 from deviating against the guide direction when the saw blade S is immersed in the workpiece. The kick-back stop 28 prevents the hand-held circular saw 70 from deviating in a direction perpendicular to the guide side 14. This prevents the hand-held circular saw 70 from being adjusted in an uncontrolled manner relative to the guide rail during this critical immersion process. As mentioned above, the positioning unit 20 can have two cutting length adjustment elements 40. Accordingly, the positioning unit 20 can be aligned to a mark on the workpiece either on the left or right side as viewed in the guide direction. If, for example, the contact edge 13 arranged in the area of the saw blade S is difficult to see (for example when sawing close to a wall), the positioning unit 20 can be aligned to the mark on the workpiece using the cutting length adjustment element 40 arranged on the fastening side. To limit the end of the cut, a further cutting length limiting device with a positioning unit 20 can be used. This positioning unit 20 can again have a fastening section 21 for connection to the guide rail. The positioning unit 20 can have at least one Page 28 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 Cutting length adjustment element 40. Preferably, the fastening section 21 with its arm 24 is structurally identical to the positioning unit 20 described above for limiting the start of the cut. More preferably, the same supports 25 can be installed on both positioning units 20, for which purpose corresponding holders 21.4 can be provided on the two positioning units 20. In addition, the cutting length adjustment elements 40 can also be designed essentially as identical parts, although the scales 42 of the cutting length adjustment elements 40 for limiting the start and end of the cut differ, since different scaling is necessary due to the pivoting kinematics of the hand-held circular saw 70, as illustrated in Figure 1. As already explained above, the cutting length limiting device for limiting the end of the cut has an end position stop 23.1 opposite the start position stop 23.2. This end position stop 23.1 is aligned with a counter stop of the hand-held circular saw 70, whereby the counter stop is preferably formed by the base plate 71. The cutting length limiting device for limiting the end of the cut is aligned, like the cutting length limiting device for limiting the start of the cut, with a mark on the workpiece that indicates the planned end of the cut. To avoid repetition, reference is made to the above explanations. If the hand-held circular saw 70 is now advanced in the guide direction, the guide movement at the end of the cut is limited with the end position stop 23.1. The saw blade S has then reached the end of the cut and the saw cut is complete. It may now be the case that, for example due to resharpening/wear of the saw blade S or other influences, even if the scales 42 are correctly aligned with the scribe marks, the planned cut start or the planned cut end are not produced exactly in the workpiece. Page 29 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 In this case, a correction can be made using the adjustment element 26 with the aid of a test cut. Accordingly, the test cut with a predetermined cutting depth is first made in a test workpiece. Then the extent of the offset of the start/end of the cut is determined compared to the scale value of the cutting length adjustment element 40 corresponding to the cutting depth. This offset can be corrected using the adjustment element 26. The cutting length adjustment element 40 is then precisely adjusted again relative to the carrier 25 and thus relative to the fastening section 21. Another invention is shown in Figures 34a and 34b. As this illustration shows, a positioning unit 20 is used. This positioning unit 20 can be designed as described above and/or designed as described in the claims. To avoid repetition, reference is therefore made to the above statements or to the claims, which can also apply in the same way to the positioning unit 20 of Figures 34a and 34b. As the illustrations illustrate, the positioning unit 20 has at least one additional component interface 29. The additional component interface 29 can be provided on the boom 24 and/or on the holder 21.4. Preferably, an additional component interface 29 is provided on both the holder 21.4 and the boom 24. The design of the additional component interface 29 is shown by way of example in Figures 36 and 37. Figure 36 illustrates the additional component interface 29 in the area of the holder 21.4 and Figure 37 illustrates the additional component interface 29 in the area of the boom 24. As Figure 36 shows, the additional component interface 29 has at least one stop 29.5. Furthermore, the additional component interface 29 may have at least one coding element 29.6, 29.7. In the present embodiment, two coding elements 29.6, 29.7 are used, which Page 30 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 can have different geometric designs. As Figure 36 shows, the first coding element 29.6 can be smaller than the second coding element 29.7. The second coding element 29.7 can protrude further beyond the outside of the holder 21.4, which in this case results in the different geometry. The coding can also be represented in different geometries, for example the first and second coding elements can have a different diameter, i.e. the vertical length perpendicular to the interface 29 of the coding elements does not necessarily have to be different. Figure 36 also illustrates that the additional component interface 29 can have at least one magnet 29.8 (or a counter magnet, for example a ferromagnetic part). In the present exemplary embodiment, the magnet 29.8 is arranged in the area between the two coding elements and/or in the area between the two stops 29.5. The design of the additional component interface 29 in the area of the boom 24 (see Figure 37) essentially corresponds to the design of the additional component interface 29 that was explained above with reference to Figure 36, which is why reference is made to the above statements. In particular, the two coding elements 29.6, 29.7 can be designed symmetrically to the central longitudinal axis of the positioning unit and are identical in mirror image. A cutting length adjustment element 40, as shown by way of example in Figure 35, can be exchangeably attached to the additional component interfaces 29. The cutting length adjustment element 40 essentially corresponds to the cutting length adjustment element 40 as described with reference to Figures 1 to 16, which is why reference can be made to the above statements. Therefore, only the differences are explained below. The cutting length adjustment element 40 again has a guide 27 on which a scale 42 is slidably guided. The scale 42 can again be adjusted linearly via the adjustment element 26. Page 31 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023, the adjustment movement running in the direction of the central longitudinal axis M of the cutting length adjustment element 40. As can be seen from Figure 35, a pointer 46 can be assigned to the scale 42. The pointer 46 can be moved along the scale 42 in the direction of the central longitudinal axis M. In the present embodiment, the pointer 46 in Figure 35 is set to the value “60”. This corresponds to a cutting depth of the hand-held circular saw 70 of 60mm. The pointer can carry a marking element 46.1 which can be aligned with a mark on a workpiece. To facilitate operation, the pointer 46 has a handle element 46.2. It is preferably provided that the pointer 46 consists of a transparent material at least in parts in order to minimize parallax errors. As mentioned above, the scale 42 can be moved by means of the adjusting element 26. A clamping element 45 is used to secure the setting position after the scale 42 has been set. Preferably, the clamping element 45 is designed to fix, preferably clamp, the scale 42 to the guide section 43. The drawings further illustrate that the cutting length adjusting element 40 forms an additional component 60. This additional component 60 includes, among other things, a component carrier 61 on which the guide section 43 is held. The component carrier 61 has at least one connecting section 62. In the present embodiment, two connecting sections 62 are provided on opposite sides. Preferably, the two connecting sections 62 are provided symmetrically to the central longitudinal axis M on both sides of the component carrier 61. The at least one connecting section 62 is provided with recesses 62.9, wherein the recesses 62.9 are adapted to the geometry of the coding elements 29.6, 29.7 of the additional component interface 29. Page 32 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 Figure 38 shows that a coding receptacle 26.2 can be provided on a cutting length adjustment element 40 in order to accommodate at least one of the coding elements 29.6, 29.7. In the exemplary embodiment shown, the coding element 29.6, which has a larger projection over the additional component interface 29, is passed through the recesses 62.9 in the connecting section 62 and projects into the coding receptacle 26.2. The connecting section 62 thus attaches to the stops 29.5 of the associated additional component interface 29. The connecting section 62 is held securely to the additional component interface 29 via the magnetic force of the magnet 29.8. It may be the case that the coding elements 29.6, 29.7 are designed in their geometric form in such a way that they also form alignment elements by means of which the correct positional assignment of the cutting length adjustment element 40 to the positioning unit 20 is ensured. Figure 39 illustrates the function of the two coding elements 29.6, 29.7. As this illustration shows, the cutting length adjustment element 40 attached to the additional component interface 29 does not have a coding receptacle 26.2, so that it cannot be mounted on the positioning unit 20. A user thus recognizes that he has not assigned the appropriate additional component 60 to the additional component interface 29. Via the coded additional component interface 29, it is possible in particular to assign the respective cutting length adjustment elements 40 with the scales 42 suitable for the starting position stop 23.2 and the end position stop 23.1 to the positioning unit 20, which forms the starting position stop 23.2, and the positioning unit 20, which forms the end position stop 23.1 for the planned saw cut. Figure 2 shows a further variant of the invention. The same components are marked with the same reference numerals so that reference can be made to the above statements to avoid repetition. Page 33 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 The two embodiments differ in particular with regard to the design of the supports 25. In the embodiment according to Figure 2, the support 25 has a sacrificial section 25.1. The sacrificial section 25.1 is designed such that it protrudes into the cutting area of the saw blade S, as illustrated in Figure 2. To produce a test cut, the guide rail described above is placed on the upper side of a workpiece serving as a test workpiece. The two positioning units 20 are attached to the guide rail according to Figure 2. The hand-held circular saw 70 is stopped on the left-hand positioning unit 20 (i.e. the starting position stop 23.2 and/or the kick-back stop 28). Then a test cut is made in the workpiece with a predetermined cutting depth (in this example 60 mm), whereby the saw blade S of the hand-held circular saw 70 is immersed in the workpiece. The hand-held circular saw 70 is then moved in the guide direction towards the right-hand positioning unit 20 until it hits the end position stop 23.1. In this case a test cut with a cut start and cut end is made in the workpiece, whereby the saw blade S also simultaneously cuts into the sacrificial sections 25.1 and cuts out a sawn-in area 25.2 from the sacrificial sections 25.1 of the two supports 25. The long ends of the sawn-in area 25.2 in the guide direction show the cut start and the cut end of the test cut. The marking on the scale 42 of the cutting length adjustment element 40 (here: 60 mm) that correlates with the cutting depth can now be aligned to the actual start of the cut or the actual end of the cut (of the sawn-in area (25.2). The scale 42 is thus precisely calibrated. Accordingly, the scale can be aligned precisely to the scribe mark of a workpiece to be machined for a subsequent saw cut. Page 34 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 In the case of planned machining carried out with a cutting depth corresponding to the test cut, the long ends of the sawn-in area can be brought into line with the scribe mark on the workpiece in order to achieve exact alignment of the positioning units 20. This is advantageous for so-called repeat cuts, in which the same cuts are to be made repeatedly in several workpieces. Figure 4 illustrates that the supports 25, at least in the area of the contact edge 13 of the guide rail, are preferably designed in such a way that the upper sides of the cutting length adjustment elements 40 are at least partially offset from the guide side 14 of the guide rail in the direction of the support surface 15 on the underside. This makes it possible for the pivot assembly 74 to be pivoted relative to the base plate 71 in at least a partial pivot range without the pivoting movement of the pivot assembly 74 being hindered by the cutting length adjustment elements 40. As Figure 11 illustrates, at least one of the cutting length limiting devices can be equipped with one or more additional component interfaces 29. The additional component interface 29 can be arranged at any point on the cutting length limiting device. The additional component interface 29 can preferably be arranged in the area of the positioning unit 20 on the side opposite the fastening section 21, i.e. in the area of the contact edge 13 of the guide rail. As Figure 11 shows, the additional component interface 29 can be arranged in the area of the boom 24 or can be formed by it. The additional component interface 29 can be designed as a plug-in receptacle. It can be formed in the area between the top of the boom 24 and the bottom of the boom 24. In this way, the interface is integrated into the positioning unit 20 in a space-saving manner. Page 35 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 A component carrier 61, preferably replaceable (without tools), can be connected to the positioning unit 20 via the additional component interface 29, as illustrated, for example, in Figure 12. Figure 12 further shows that the component carrier 61 can have a connecting section 62. The connecting section 62 is designed and prepared to be connected to the positioning unit 20 via the additional component interface 29. For example, the connecting section 62 can be designed as a plug-in attachment, as shown in Figure 12. This plug-in attachment can be plugged into the plug-in receptacle of the additional component interface 29. The additional component interface 29 can be designed such that, at the user's discretion, the connecting section 62 can be connected to the additional component interface 29 in different positions or orientations. Figure 12 illustrates that the connecting section 62 has locking receptacles 62.1. The locking receptacles 62.1 are arranged at a distance from one another so that the connecting section 62 can be mounted transversely to the longitudinal alignment of the guide rail in different positions on the positioning unit 20, in particular by means of counter-locking elements 29.1 arranged in the additional component interface 29 can be locked in different positions. It is also conceivable that the connecting section 62 is held in a continuously adjustable manner on the additional component interface 29. Additionally or alternatively, it can also be provided that the component carrier 61 is connected to the connecting section 62 via a bearing part 64. A rotary and/or pivot bearing can be formed in the area between the bearing part 64 and the component carrier 61. The component carrier 61 can thus be positioned in different orientations relative to the bearing part 64 and thus relative to the guide rail. In the embodiment shown, the pivot axis runs vertically to the guide side 14 of the guide rail. Page 36 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 In principle, it is also conceivable that the pivot bearing can be designed as a ball joint. Figure 12 illustrates that an additional component in the form of a lamp 63 can be connected to the component carrier 61. The lamp 63 can preferably be attached to the positioning unit 20 in the area of the contact edge 13, which serves to limit the end of the cut. This is illustrated in Figure 1. Accordingly, the lamp 63 is arranged so that the light path of the lamp is arranged against the guide movement of the hand-held circular saw 70. The lamp 63 thus illuminates the working area of the hand-held circular saw 70, i.e. the area in which the saw blade S penetrates the workpiece. It can be provided that, similar to a flashlight, the lamp 63 has a mechanical on/off function. Additionally or alternatively, it can also be provided that a vibration sensor is present on one of the machine components, advantageously on the lamp 63 itself. By means of a control circuit connected to the vibration sensor, the lamp 63 can be switched on when the hand-held circular saw 70 is activated or switched off when the hand-held circular saw 70 is deactivated. It is also conceivable that a radio receiver is present on the lamp 63, which switches the lamp on and/or off when it receives a radio signal, for example from the hand-held circular saw 70. Additionally or alternatively, a sawdust collector hood 65 can be attached to the or another additional component interface 29 as an additional component. Preferably, a component carrier 61 is used again, which has a connecting section 62 for connection to the additional component interface. Page 37 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 It is conceivable that the connecting section 62 corresponds in principle in its structure to the connecting section 62 according to Figure 12, so that the chip collection hood 65 can be fixed in different adjustment positions. Furthermore, it is conceivable that the bearing part 64 shown in Figure 12 is designed in such a way that the component carrier 61 is detachably connected to the bearing part 64. Then, instead of the component carrier 61, which carries the lamp 63, the component carrier 61 according to Figure 13, which carries the sawdust collection hood 65, can be connected directly or indirectly to the bearing part 64 in a kit-like manner. It can also be the case that a rotary and/or pivot bearing is again formed, with which the chip collection hood 65 can be pivoted relative to the bearing part 64. As can be seen from Figures 13 and 14, the sawdust collector hood 65 has a catching body. The catching body can have a discharge connection 66. For example, a suction hose of a chip discharge, for example of a vacuum cleaner, can be connected to the discharge connection 66. In the area of the contact edge 13, the chips cut off from the workpiece are thrown off against the guide direction of the hand-held circular saw 70 during machining. These chips can be at least partially caught in the chip collector hood 65 and discharged in an orderly manner via the discharge connection 66. Figures 15 and 16 show a further design variant of a cutting length limiting device with a positioning unit 20. In Figures 15 and 16, identical components are marked with the same reference numerals. To avoid repetition, reference can be made to the above explanations. Therefore, only the differences to the embodiment according to Figures 1-14 will be discussed below. Figures 15 and 16 show an alternative embodiment of the cutting length limiting device in which the starting position stop 23.2, rather than the cutting length setting element 40, is adjustable. Page 38 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 The cutting length limiting device again has a positioning unit 20 which is designed to be connected to the positive guide 10 as previously described. The positioning unit 20 again has lateral supports 25 which carry a cutting length adjustment element 40. In particular, it can be the case that the cutting length adjustment element 40 with its scale 42 is held on the support 25 so that it cannot be moved, in particular so that it cannot be moved in the direction of the cutting direction of the circular saw 70. In order to align the scale 42 with respect to a workpiece-side mark, the start position stop 23.2 is arranged on the cutting length limiting device, in particular on the positioning unit 20 and further preferably in the region of the fastening section 21. In contrast to the embodiment described above, the starting position stop 23.2 is held adjustably on the positioning unit 20. For this purpose, it can be provided, for example, that an adjusting element 26 is used which is carried by the positioning unit 20, in particular in the area of the fastening section 21, with which the starting position stop 23.2 can be adjusted. The adjustment direction of the starting position stop 23.2 is in the direction of the cutting direction of the hand-held circular saw 70, i.e. for example from left to right in Figure 16 (and vice versa). The adjustment of the starting position stop 23.2 on the positioning unit 20 is preferably stepless. For this purpose, it can be provided that a threaded connection is effective between the starting position stop 23.2 and the adjusting element 26. Figure 15 illustrates that an adjusting element holder 26.1 can be present on the positioning unit 20, in which the adjusting element 26 is received in a protected manner and accessible from above (Figure 16). To align the positioning unit 20, the hand-held circular saw 70 is placed with its stop, for example the base plate 71, against the starting position stop 23.2. A test cut can then be made in a test workpiece. If the start of the cut of this test cut does not match the corresponding marking on the scale 42, the entire positioning unit 20 can be moved relative to the hand-held circular saw 70 using the adjustable starting position stop 23.2 until the start of the cut matches the corresponding marking (corresponding to the depth setting on the hand-held circular saw 70). The positioning unit 20 Page 39 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 is then aligned exactly opposite the saw blade S and thus the hand-held circular saw 70. Figure 17 shows a further design variant of a positioning unit 20. The design of this positioning unit 20 essentially corresponds to the design of the positioning unit 20 according to Figures 1 to 16. Reference can therefore be made to the above statements. Therefore, only the differences are explained below. As Figure 17 shows, the positioning unit 20 again has at least one additional component interface 29 to which or in which an additional component 60 can be mounted. Figure 17 shows an example of a positioning unit 20 with two additional component interfaces 29 in the area of the boom 24. In particular, the additional components 60 described in the previous examples can be mounted on the additional component interface 29 if they are designed accordingly in the transition area in which they connect to the additional component interface 29. Figure 17 illustrates that an additional component 60 can be mounted with the additional component interface 29, which has a cutting width compensator 67. The design of such an additional component 60 is shown as an example in Figure 18. As this illustration illustrates, the additional component 60 can have a connecting section 62, which is designed to connect the additional component 60 to the additional component interface 29. For this purpose, it can be provided that the connecting section 62 has a support surface 62.4, with which it rests on an upwardly directed guide surface 29.2, preferably to form a linear guide. Page 40 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 Additionally or alternatively, it can be provided that the additional component 60 has a guide area 62.5 which forms a guide, in particular a linear guide, with a guide element 29.3 of the positioning unit, in particular the additional component interface 29. It can be the case that the guide area 62.5 is formed by a side wall which is guided linearly on a guide surface of the guide element 29.3. The guide direction of the additional component 60 preferably runs vertically to the cutting direction of the hand-held circular saw 70. Figure 18 further illustrates that the additional component 60 has a fastening receptacle 62.2, which can preferably be designed in the form of an elongated hole. A fastening element 62.3 can be passed through the fastening receptacle 62.2. For example, the fastening element 62.3 can be a fastening screw that is screwed into a threaded receptacle 29.1 of the positioning unit 20. If the additional component 60 is provided with a recess 62.6 within which the screw head of the fastening element 62.3 is at least partially received, a compact design is achieved, as shown in Figure 18. The additional component 60 can be adjusted in its sliding guide perpendicular to the feed direction of the hand-held circular saw 70. The adjustment is simplified with a handle 62.7 of the additional component 60. As shown in Figure 19, the handle 62.7 can have a structured surface to make operation easier. Figure 18 further shows that the additional component 60 has a cutting width compensator 67. The cutting width compensator 67 can be coupled in one piece to the connecting section 62 by means of a component carrier 61. Preferably, the cutting width compensator 67 is held offset by means of the component carrier 61 in the direction of the underside of the positioning unit 20. For example, it may be the case that a support surface 67.3 Page 41 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 of the cutting width compensator 67 is held at a short distance from the top of a workpiece 100 (see Figure 19), or ideally sits on the top of this workpiece 100. The cutting width compensator 67 has a marking edge 67.2, which is preferably designed in the form of an edge. The marking edge 67.2 can be molded onto a shoulder 67.1, as illustrated in Figure 18. With the cutting width compensator 67, the cutting width of a saw blade S of the hand-held circular saw 70 can be at least partially taken into account during the work process. This is explained in more detail in the following Figures 19-24. Figure 19 shows the assignment of the positioning unit 20 to a workpiece 100. The guide rail is omitted from the drawing for better clarity. As explained above, the guide rail can be placed on the top of the workpiece 100, the positioning unit 20 can be suitably attached to the guide rail and a saw cut 100 can be made with the hand-held circular saw 70, for example in the form of a test cut in a test workpiece 100. This results in the saw slot 101. The saw slot 101 has an outer saw slot boundary 102 (facing away from the fastening section 21) and an inner saw slot boundary 103 (facing the fastening section 21), as Figure 20 shows more clearly. Once the saw slot 101 has been made, the cutting width compensator 67 can be aligned, for example, with the outer saw slot boundary 102, for which purpose the marking land 67.2 is brought into alignment with the outer saw slot boundary 102. This is illustrated in Figure 20. The additional component 60 can then be firmly and immovably connected to the positioning unit 20 by means of the fastening element 62.3. Page 42 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 Figure 19 shows the positioning unit 20, which in Figure 1 forms the left-hand stop limit for the hand-held circular saw 70. In the same way, the right-hand positioning unit 20, which limits the end of the saw cut 101 with its end stop 23.1, can also be equipped with a cutting width compensator 67. This means that this second cutting width compensator 67 can also be aligned with the outer saw slot limit 102. If the positioning units 20 adjusted in this way with their cutting width compensators 67 are now aligned with a scribe mark on a workpiece 100 to be machined, the user can take the width of the saw blade S into account exactly when creating his saw slot 101. Figures 21 and 22 illustrate that it is not only possible to align the cutting width compensator 67 with the outer saw slot boundary 102. Rather, it is also possible to align the cutting width compensator 67 exactly with the center of the saw slot 101 between the inner saw slot boundary 103 and the outer saw slot boundary 102. Figures 23 and 24 illustrate that the cutting width compensator 67 is adjustable within a larger adjustment range, preferably continuously. This takes into account that saw blades S with different saw blade widths can be mounted on the hand-held circular saw 70. Figure 25 shows a further design variant of a positioning unit 20. The design of this positioning unit 20 essentially corresponds to the design of the positioning unit 20 according to Figures 1 to 24. Reference can therefore be made to the above statements. Therefore, only the differences are explained below. The positioning unit 20 has an additional component interface in the area of the free end of the boom 24. In addition, an additional component interface 29 can also be provided on the holder 21.4 on the opposite side. Page 43 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023. The additional component interfaces 29 are preferably identical. The additional component interface 29 has at least one projection 29.4 which engages in a recess 62.9 of the additional module 60 in order to align this additional module 60 with respect to the positioning unit 20. Of course, it is also conceivable the other way around, that the positioning unit 20 has the recess 62.9 and the additional module 60 has the projection 29.4. The additional component interface 29 can be equipped with a magnet for fastening the additional component 60, which works together with a counter magnet of the additional component 60 in order to hold the additional component 60 on the positioning unit 20 in an interchangeable manner. The structure of the additional component 60 is shown in more detail in Figures 26 and 27. As these illustrations show, the additional component 60 has a component carrier 61, which can be made from a sheet metal blank and formed as a stamped and bent part, for example. The component carrier 61 has at least one connecting section 62, which is preferably provided with the recess(es) 62.9. In the present exemplary embodiment, two connecting sections 62 are used, which are preferably of identical construction. As Figure 27 illustrates, the two connecting sections 62 can be designed as wall elements that are arranged at a distance from one another. In the area between the connecting sections 62, the component carrier 61 forms a receptacle for a supporting part. The supporting part is equipped with a base-side guide surface 62.5, which is placed on a support surface formed between the two connecting sections 62. The supporting part is provided with an opening that forms a fastening receptacle 62.2. A fastening element 62.3 in the form of a threaded bolt can be placed through this fastening receptacle 62.2. The threaded bolt can protrude from the guide surface 62.5. Page 44 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 A nut 69 is used to fix the support part to the component carrier 61. This can be screwed onto the fastening element 62.3 to clamp the support part to the component carrier 61. If the nut 69 is loosened, the support part can be adjusted relative to the component carrier 61 transversely to the cutting direction of the circular saw 70. For guided adjustment, a linear guide is formed between the support part and the component carrier 61. It can be provided that counter-guide elements 62.8 are provided on the support part, which work together with guides 68 of the component carrier 61. It may be the case that the counter-guide elements 62.8 form projections that protrude from the underside of the support part and that engage in guides 68 of the component carrier 61 designed as recesses, as shown in Figure 27. The support part has a projection 67.1 on both sides adjacent to the fastening receptacle 62.2. Each of these projections 67.1 is equipped with at least one marking edge 67.2. In the present exemplary embodiment, a marking edge 67.2 is provided on opposite sides of the projections 67.1. It may be the case that the underside of the projections 67.1 form a support surface 67.3 that faces the top of a workpiece 100 to be machined. Figure 26 shows the assembled state of the additional component 60. In order to connect this additional component 60 to the positioning unit, the component carrier 61 only has to be pushed with its at least one recess 62.9 onto the associated projection 29.4. Then the magnetic connection between the additional component 60 and the positioning unit 20 becomes effective, so that the additional component 60 is fixed in alignment to the positioning unit 20. The assembly state is shown in Figure 25. According to a preferred variant, it is possible for the additional component 60 to be attached to the additional component interface 29 of the Page 45 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 boom 24 or holder 21.4. The assembly on the holder 21.4 is shown in Figure 33. In the same way as in the embodiment according to Figures 17-24, a test cut can again be made in a test workpiece 100 using the additional component 60 mounted on the positioning unit 20, and the position or width of the saw blade S can be taken into account. For this purpose, the cutting width compensator 67 or the two cutting width compensators 67 provided on the support part are aligned with the saw slot 101 created. Figure 28 shows the alignment at the outer saw slot boundary 102 and Figures 29 and 30 show the alignment of the cutting width compensators 67 in the middle of the saw slot 101. Figures 31 and 32 show, similar to Figures 23 and 24, the maximum laterally extended positioning of the cutting width compensators 67. Page 46 of 51

Claims

Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 Claims 1. Positioning unit (20) for a machine tool, in particular a hand-held circular saw (70), wherein the positioning unit (20) has a fastening section (21) for the replaceable fastening of the positioning unit (20) to a positive guide (10), in particular to a guide rail, and wherein the positioning unit (20) has on one stop side a machine tool stop, in particular a start position stop (23.2) and/or an end position stop (23.1), for limiting the movement of the machine tool on the positive guide (10) in or opposite to a guide direction, characterized in that the positioning unit (20) has at least one additional component interface (29) to which an additional component (60) is fastened, preferably replaceably fastenable. 2. Positioning unit (20) according to claim 1, characterized in that a boom (24) is coupled to the fastening section (21), and that the boom (24) has the additional component interface (29) at its end region opposite the fastening section (21) in order to hold the additional component (60) in the region of a contact edge (13) of the positive guide (10), in particular the guide rail. 3. Positioning unit (20) according to claim 1 or 2, characterized in that the additional component (60) has a bearing part (64) which carries a connecting section (62), and that the connecting section (62) is held on a receptacle of the additional component interface (29). 4. Positioning unit (20) according to claim 3, characterized in that the additional component (60) can be connected to the additional component interface (29) in different positions and/or orientations by means of the connecting section (62). Page 47 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 5. Positioning unit (20) according to claim 3 or 4, characterized in that the connecting section (62) of the additional component (60) has at least one locking receptacle (62.1) by means of which the connecting section (62) is fastened to a counter-locking element (29.1) of the additional component interface (29) or that the connecting section (62) of the bearing part (64) can be adjusted continuously or in steps relative to the additional component interface (29) by means of an adjustment device. 6. Positioning unit (20) according to one of claims 3 to 5, characterized in that a component carrier (61) is used which is connected to the bearing part (64) in a rotatable and/or pivotable manner by means of a bearing, and that the component carrier (61) carries the additional component (60) directly or indirectly, preferably receives it in an interchangeable manner. 7. Positioning unit (20) according to one of claims 1 to 6, characterized in that a detachable force-fit and/or a material-fit connection is effective between the connecting section (62) of the additional component (60) and the additional component interface (29), wherein in particular an adhesive connection can be provided. 8. Positioning unit (20) according to one of claims 1 to 7, characterized in that the additional component (60) is continuously or stepwise adjustable, in particular displaceable, transversely to the guide direction relative to the positioning unit (20). 9. Positioning unit (20) according to one of claims 1 to 8, characterized in that the additional component (60) has a lamp (63), a chip collecting hood (65), a spotlight, a laser and/or a cutting width compensator (67). 10. Positioning unit (20) according to claim 9, characterized in that the chip collecting hood (65) has a collecting body to which a discharge connection Page 48 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 (66), wherein the discharge connection (66) preferably has an interchangeable coupling element for connecting a dust extraction system. 11. Positioning unit (20) according to one of claims 1 to 10, characterized in that a cutting length adjustment element (40) is preferably adjustably attached to a carrier (25) or the additional component interface (29), wherein the cutting length adjustment element (40) is held in the region of the fastening section (21) or the/an extension arm (24) of the positioning unit (20), and that the cutting length adjustment element (40) protrudes beyond the fastening section (21) in or opposite to the guide direction. 12. Positioning unit according to one of claims 9 to 11, characterized in that the cutting width compensator (67) has a marking edge (67.2) on at least one extension (67.1), which extends in particular in the guide direction, and that the extension (67.1) is coupled directly or indirectly to the connecting section (62) via a component carrier (61). 13. Positioning unit according to one of claims 9 to 12, characterized in that the at least one cutting width compensator (67) is adjustable via a sliding guide relative to the positioning unit (20), in particular in a direction transverse to the guide direction and/or in the direction of the boom (24), preferably continuously, wherein the adjustment direction of the sliding guide preferably runs transversely to the guide direction. 14. Positioning unit (20) according to one of claims 1 to 13, characterized in that the positioning unit (20) has a kick-back stop (28) for a counter stop of the circular saw (70), wherein it is preferably provided that the kick-back stop (28) has a height stop which is arranged at a distance from a fastening side of the fastening section (21) to form a spacing area and is aligned facing this. 15. Positioning unit (20) according to one of claims 1 to 14, characterized in that the fastening section (21) has a clamping element (80) and/or Page 49 of 51 Applicant: Festool GmbH Our reference: A 31399-PCT Date: December 21, 2023 carries a fixing element which is adjustable between a release position and a clamping position, that the fastening section (21) has at least one recess (21.1, 21.2) open towards the fastening side, and that the clamping element (80) engages at least partially in the recess (21.1, 21.2) in the clamping position and releases an engagement area of the recess (21.1, 21.2) in the release position. 16. Positioning unit (20) according to one of claims 1 to 15, characterized in that a guide carrier (23) is connected to the fastening section (21), which has a recessed, preferably groove-shaped, linear guide receptacle (22), wherein the linear guide receptacle (22) is arranged at a distance from an engagement section (21.3) formed by the fastening section (21) and designed in the form of a protruding projection. 17. Guide assembly for a machine tool, in particular a hand-held circular saw (70), with a positioning unit according to one of claims 1 to 16 and a positive guide (10) in the form of a guide rail, wherein the guide rail has a guide groove (11) running in the guide direction and/or a guide web running in the guide direction, wherein the guide rail forms a fastening longitudinal side running in the guide direction and opposite it a cutting edge side with a contact edge (13), wherein the positioning unit (20) with the fastening section (21) is detachably connected to the guide rail in the region of the fastening longitudinal side, and that the additional component (60) is held laterally next to the contact edge (13) in the region of the cutting edge side. Page 50 of 51