WO2005001181A1 - Detector for detecting when the thread bobbin in a thread-processing system has to be replaced - Google Patents

Abstract

The invention relates to a detector (D) for detecting when the thread bobbin in a thread-processing system (S) has to be replaced. Said detector comprises a movably received element (E), at least one detection member (7) that responds to a relative position or a relative position change of the element with a signal (i), and a power generator that exerts a force on the element, and the element (E) can be adjusted during the replacement. The force is oriented in the direction of movement of the element (E) towards the detection position (P). The positioning device is provided with a thread clamping area (6, 6') that is arranged relative to the path of travel of the element in such a manner that the positioned thread (Y), until the replacement, forms a barrier for the element (E) against a movement towards the detection position (P) in response to the exerted force. The thread, during replacement, becomes detached in such a manner that the element (E) automatically moves towards the detection position (P).

Description

 Detector for changing the bobbin in a thread processing system

The invention relates to a detector specified in the preamble of claim 1.

The detector known from EP 0 454 199 A has an asymmetrical two-armed, pivotably mounted angle lever. Due to the asymmetry, a force generator is integrated for a force which, as an element, brings one arm into the loading position and holds it there. The positioned thread is arranged behind the arm in a receptacle, the opening of which is blocked by the arm. When changing, the thread is pulled out of the opening, relocating the arm to the detection position and releasing it. When the detection position is reached, the angle lever actuates a switch which emits the signal for the change that has taken place. An additional device holds the pivoted angle lever so that the arm blocks the opening of the receptacle again. When loading the detector, the angle lever is pivoted over the arm by the thread until the thread has reached the arm again and the angle lever assumes the loading position. Since the thread has to overcome the force acting on the angle lever during the change and, if necessary, is strongly deflected, a pronounced increase in tension occurs in the thread, which can be the cause of a thread break.

In practice, an optoelectronic detector of this type is also known, in which plate brakes are arranged on both sides of a mouth open at one end, which together with the mouth form the positioning device for the thread. The plate brakes are arranged in relation to a light barrier passing through the mouth in such a way that the positioned thread is held on the side of the light barrier facing away from the mouth opening. When changing, the thread is released from the disc brakes and pulled through the light barrier. The temporary and rapid shading of the light barrier generates a signal indicating the change. To load the detector, the thread is inserted into the plate brakes by hand. Since this movement is slow, a signal is suppressed, for example by means of a filter. If necessary, this slow loading movement is converted into another signal, which provides confirmation of the correct loading of the detector. The opto- The operational safety of the electronic detector suffers from unavoidable soiling and must be individually adjusted to different thread qualities and / or strengths.

The invention has for its object to provide a detector of the type mentioned, which is reliable and in which the risk of thread breakage is eliminated when changing.

The object is achieved with the features of claim 1.

In a departure from the known principle of the mechanical detector mentioned at the outset that the element is changed by the thread against the acting force when changing the thread spool, the detector according to the invention is designed such that the thread only has to overcome the holding force in the thread clamping area when changing the thread spool , The holding force can be set so low that sensitive thread material is not damaged when changing the bobbin, and just high enough to prevent the element supported by the thread from moving automatically under the force. Due to the force, the element can first follow the detaching thread without the element actively moving or being undesirably deflected on the element. The thread that comes off when changing the bobbin only allows the element to move automatically from the loading position blocked by the thread into the detection position. This eliminates the risk of thread breakage.

When changing the bobbin, the thread moves essentially in the same direction from the thread clamping area in which the element also moves, at least with one movement component, to the detection position.

The element is expediently a two-armed, essentially straight swivel lever which responds with one arm to the movement of the thread when it is released from the thread clamping area and follows the thread which is moving away, while with its other arm it generates the signal which indicates the change of the thread spool. In an expedient embodiment, the signal processing electronic components, for example on a circuit board, are hermetically shielded from the outside in the housing of the detector. In this technology, unavoidable soiling such as fluff, dust and possibly finish can have no disruptive influence on the possibly sensitive electronic components.

In a preferred embodiment, at least one leaf spring penetrable by the element is provided in the thread clamping area, which fixes the thread very gently and precisely at a desired position on a support surface of the housing of the detector. Alternatively, at least one holding device arranged laterally next to the path of movement of the element, e.g. a disc brake define the thread clamping area ..

A permanent magnet is expediently provided in the element. The permanent magnet can, preferably, perform a double function. On the one hand, the permanent magnet cooperates with a stationary iron body to form the force generator, which generates the force that tracks the element as the thread loosens. On the other hand, the permanent magnet can interact with a stationary Hall sensor, which forms the detection element providing a signal. The signal is generated when the permanent magnet is in the vicinity of the Hall sensor, or has moved or has moved away from the Hall sensor. The signal is processed to indicate a change that has taken place and / or, if appropriate, as an indication of the loading of the detector with the thread. Alternatively, it is possible to provide a further detection element, which cooperates with the permanent magnet or another transmitter, and with which a charge signal is generated.

Alternatively, the force generator could be at least one spring acting on the element, wherein the spring force should be oriented in the direction in which the element moves from the loading position into the detection position.

The iron body is expediently positioned such that the force is strongest in the detection position and weakest in the loading position. This is favorable because the thread in the loading position is only slightly loaded by the element that is , but then safely reached the detection position under the increasing force after loosening the thread.

A straight, two-armed pivot lever that is balanced in the pivot bearing is particularly advantageous. As a result, the detector works the same regardless of its mounting position in the room.

Finally, it is expedient if the element has an effective length at its end cooperating with the thread, thanks to which the thread can in no case be moved past the element. Certain geometrical relationships ensure that the thread can never get behind the element.

In a favorable embodiment, the element is a spiral spring biased in the loading position by the force, preferably a leaf spring. This embodiment is structurally very simple and reliable because the element does not require any movement support.

Since a leaf spring is in any case expedient for positioning the thread in the clamping area, in a further advantageous embodiment the spiral spring which forms the element is an integral part of the leaf spring for fixing the thread in the clamping area, more precisely on at least one contact surface. The leaf spring thus has a double function, which reduces the number of parts of the detector.

The leaf spring expediently has two outer prongs with which the thread is positioned on both sides of the element formed by the spiral spring in the clamping region of the detector. The spiral spring is a central prong of the same leaf spring, which is fixed to the housing, preferably at the inlet of a mouth to the clamping area, with a bending pretension. The outer tines only need to move relative to the contact surface in order to change the thread thickness, while the spiral spring formed by the central tine can additionally move over its path of movement into the detection position. The pretension with which the outer tines and the spiral spring are applied expediently comes from a common clamping point or fixing place the leaf spring. In itself, an outer prong would be sufficient to fix the thread.

The outer prong is expediently wider than the central prong from which the spiral spring is formed. As a result, the outer tine is more rigid than the spiral spring.

In principle, it can be expedient to design the spiral spring and the outer tine with different preloads and / or spring properties, in coordination with the different properties. The task of the outer tine is to position the thread in the clamping area as gently but reliably as possible. The spiral spring, on the other hand, has the task of executing the movement to the detection position when the thread is released from the clamping area, and of loading the thread in the clamping area as gently as possible. Different preloads and / or spring properties meet these different tasks. In addition, for the spiral spring, its pretension and / or spring property should be designed so that it does not show any nervous behavior with the permanent magnet arranged on it.

It may be expedient to design the spiral spring with a constriction in its transition region into the leaf spring, so that it is relatively soft.

Additively or alternatively, each outer tine could be flexurally stiffened by at least one longitudinal bead or another stiffening structure, such as, for example, a rib-shaped housing stop which prestresses the outer tine and possibly shortens its spring length.

Embodiments of the subject matter of the invention are explained with the aid of the drawing. Show it:

1 schematically shows a thread processing system with a detector for a thread spool change, 2 shows a longitudinal section through the detector, a second embodiment being indicated by dashed lines,

3 shows a further embodiment of the detector in longitudinal section,

Fig. 4 is a detailed top view of Fig. 3, and

5 shows a further detail of FIG. 3.

In a thread processing system S in FIG. 1, two thread spools B1, B2 carrying the same thread Y are mounted on a spool stand 1, for example. A thread processing device F, for example a delivery device, pulls the thread Y from the respective thread spool B1, B2. The end of the thread Y on the thread spool B1 is connected via a node 2 to the start of the thread Y on the other thread spool B2 (pigtail). For example, a detector D is mounted on the bobbin stand 1, in which the connecting section of the threads Y is positioned.

After the thread Y is used up by the thread spool B1, a thread spool is changed to the thread spool B2, the connecting section being pulled out of the detector D and subsequently the thread Y being pulled off the second thread spool B2. During this change, the detector D generates a signal i which indicates the change. Optionally, the detector D is designed such that it emits a similar or different signal and represents the loading when loading with the thread Y. Loading is understood to mean the introduction and positioning of the connecting thread section in or in the detector D.

In the longitudinal section of the detector D in FIG. 2 it can be seen that on the underside of a housing 3 there is provided a mouth 4 open to one end (to the left), within the extension of which there is a positioning device 5 for the thread Y. The positioning device 5 has a locally defined thread clamping area 6, in which the thread Y is non-positively fixed when the detector D is loaded (as shown). The positioning device 5 with the thread clamping area 6 consists, for example, of a leaf spring C in the mouth 4 (shown in a solid line) which has a through slot, for example (not shown), which can be pressed with prestress against bearing surfaces 4a, or at least one laterally next to a bottom slot 11 of the mouth 4 arranged disc brake 6 'or another non-positive holding device.

A detection element 7, for example a Hall sensor, is arranged in the housing 3 in a stationary manner, for example on a printed circuit board H. Furthermore, a stationary iron body 8 is provided at a distance from the detection element 7. A mechanical, movably mounted element E for interacting with the thread Y, the detection element 7 and the iron body 8 is provided in the housing. In the embodiment shown, the element E is a two-armed, straight pivot lever 9, which is pivotable about a pivot axis 10 and, preferably, has a limited pivot range. In the arm 9a, a permanent magnet M is accommodated at the end, which works both with the detection element 7 (the Hall sensor) and with the iron body 8.

The arm 9b on the other side of the pivot axis 10 plunges into the longitudinal slot 11 in the housing 3 and into the leaf spring G in each pivoting position of the pivot lever 9. The pivot lever 9 is designed such that despite the permanent magnet M it is at least largely weight-balanced with respect to the pivot axis 10. The iron body 8 forms, together with the permanent magnet M, a force generator which exerts a force 13 on the element E about the pivot axis 10 in the direction of the arrow shown.

The pivot lever 9 is pivotally adjustable between the loading position L shown, in which the permanent magnet M is positioned close to the detection member 7, and a detection position P, which is indicated by a broken line. The force 13 symbolized by the arrow is weakest in the loading position shown, but becomes strongest in the indicated detection position P. As an alternative or in addition, the element E could also be acted upon by a spring in the same direction. (Similar to the embodiment of FIGS. 3, 4). When the detector D is loaded, the thread Y is brought into the position shown and fixed by the leaf spring C on the support surfaces 4a in the thread clamping area 6, the pivoting lever 9 being moved into the loading position shown and contacting the thread Y under the then relatively weak force 13 , The positioned thread Y forms a lock against a pivoting movement of the pivot lever 9 to the detection position P.

When changing the bobbin, the thread Y is released from the thread clamping area 6 or 6 'and is pulled out of the mouth 4 in the direction of an arrow 12 along the support surfaces 4a. The force 13 pivots the pivot lever 9 into the detection position P, the signal i being emitted when the detection position is reached or before. The pivot lever 9 remains in the detection position P until the next charging process.

The pivot lever 9 is expediently a light plastic molded part. The depth of penetration of the arm 9a into the longitudinal slot 11 is chosen such that the thread Y cannot pass the arm 9b within the mouth 4 within the limited pivoting range of the pivoting lever 9.

In an alternative, not shown, the arm 9a could be opto-electronically scanned against contamination in the interior of the housing 3. Furthermore, the pivot lever 9 could be assigned a further detection element for reporting or actuating the charging process. At the end of the arm 9b, a runner or a shoe with a right-hand, downward-reaching catch stop could also be provided, which is raised from the thread Y in the loading position L and lies gently on the thread Y. The arm 9b could also have a convex contact surface which, in the loading position L, touches the thread Y under the force 13.

In the embodiment of FIGS. 3 and 4, the element E carrying the permanent magnet M is a spiral spring 18, which is designed, for example, as a central prong of the leaf spring C, the outer prongs 16, 17 of which are used for positioning the thread Y in the clamping area 6 of the positioning device 5. Fig. 4 is a plan view of the leaf spring C, the , on the housing 3 (FIG. 3) between a support 22 and an abutment 23 of a clamping body 34 in fastening points 15 with prestress. The outer tines 16, 17, which are wider than the central tine, rest on the bearing surfaces 4a in the mouth 4 with a prestress (indicated by dashed lines in FIG. 3), as long as no thread Y is positioned underneath. The electronic components of the detector D which are arranged on a printed circuit board H and are not highlighted in this embodiment are hermetically shielded from the outside. The detection element 7, for example a Hall sensor, is also arranged shielded or covered, and is actuated by the permanent magnet M through a housing wall (for example made of plastic). Alternatively, as indicated by dashed lines in FIG. 3, the detection element 7 'could also be arranged in the vicinity of the detection position P (indicated by dashed lines) of the spiral spring 18. The detection element 7, 7 'could also serve to confirm the charging process.

The longitudinal slot 11 is open at the bottom, so that any lint accumulation falls down. The spiral spring 18 can be somewhat shorter than the outer tines 16, 17, so that after the thread Y is released from the position shown in full lines in the direction of the arrow 12 when the thread spool is changed, the spiral spring 18 moves into the longitudinal slot 11 into the detection position P moves, namely under the force 13 and past a transverse wall 25 of the longitudinal slot 11.

The detection position P of the spiral spring 18 could also be defined by a stop (not shown).

The function of the detector is the same as that explained with reference to FIG. 2.

The leaf spring C in FIG. 4 is designed such that the bending spring 18 as a central prong is either approximately the same width over its length or, as indicated by dashed lines, is formed via cutouts 20 with a constriction 21, which gives the bending spring 18 a different bending behavior or one give other bias as it prevails in the outer tines 16, 17. The outer tines 16, 17 can even be stiffened by longitudinal beads or other stiffening structures 25 (indicated by dashed lines), so that they have a different pretension or a different bending behavior have as the spiral spring 18. The leaf spring C can be formed by stamping or laser cutting from a rectangular leaf spring blank 14 per se. Alternatively, it would be possible to provide only one outer prong 16, 17, or to form it by, for example, a leaf spring with a higher wall thickness and / or rigidity than the separate, second and softer leaf spring or spiral spring 18 which forms the element E. In a further alternative (not shown), the bending spring 18 could also be a bending arm or bending wire (spring steel wire) soldered in the cutout between the outer tines 16, 17 in order to achieve different prestresses or bending behavior for the different tasks. This is because the outer tines 16, 17 have a clamping task, while the spiral spring 18 should stress or deflect the thread Y as little as possible and should reliably execute the stroke from the loading position L to the detection position P. The inner end of the mouth 4 is designed so that it acts as a kind of limitation when positioning the thread Y.

Instead of a Hall element as the detection element, another electronic element could be used which responds to the presence or proximity or movement of a metallic body or a magnet with a signal.

In the embodiment of FIG. 3, the permanent magnet M can be a ballast weight and help to generate the force 13 which moves the spiral spring 18 or the element from the loading position L to the detection position P.

In Fig. 5 a rib-like housing stop 26 is provided, which the outer tine 16, 17 e.g. supports and prestresses in the vicinity of the clamping point, while the central prong or spiral spring 18 extends without contact with the stop 26 up to the bearing surface 4a and is therefore softer than the outer prongs.

Claims

claims 1. Detector (D) for changing the bobbin in a thread processing system (S), with an element (E) movably mounted between a loading position (L) and a detection position (P), a thread positioning device (5) for positioning the Thread (Y) until it changes within the movement path of the element (E), at least one detection element (7) which responds to a relative position or a relative position change of the element (E) with a signal (i), and a force generator which acts on the Element (E) exerts a force (13) in at least one direction of movement of the element, the element (E) being adjustable when changing, characterized in that the force (13) in the direction of movement of the element (E) from the loading position (L) is oriented to the detection position (P) that the positioning device (5) has a thread clamping area (6) which is arranged in this way in relation to the movement path of the element (E) from the loading position (L) to the detection position (P) It is et that the thread (Y) positioned in the thread clamping area (6) forms a lock for the element (E) located in the loading position (L) against movement under the exerted force until the thread spool change, and that the thread (Y ) when changing the bobbin, releases the element (E) for automatic movement under force (13) from the loading position (L) to the detection position (P). 2. Detector according to claim 1, characterized in that the thread (Y) can be detached from the positioning device (5) in substantially the same direction when the thread spool is changed, in which the element (E) is removed from the force (13) Loading position (L) moved to the detection position (P). 3. Detector according to claim 1, characterized in that the signal (i) processing electronic components, for example on a circuit board (H), in a housing (3) of the detector (D) are hermetically shielded from the outside. 4. Detector according to claim 1, characterized in that the element (E) is a substantially straight, two-armed pivot lever (9). 5. Detector according to claim 1, characterized in that the thread clamping area (6) has at least one leaf spring (C) penetrable by the element (E) or at least one leaf spring (C) placed laterally next to the path of movement of the element (E) or a thread clamp ( 6 ') or another non-positive thread holding device. 6. Detector according to claim 1, characterized in that the element (E) has a permanent magnet (M). 7. Detector according to claim 4, characterized in that the permanent magnet (M) with a stationary iron body (8) forms the force generator. 8. Detector according to claim 1, characterized in that the force generator is a spring acting on the element (E). 9. Detector according to claim 6, characterized in that the permanent magnet (M) cooperates with a stationary Hall sensor which forms the detection element (7). 10. Detector according to claim 7, characterized in that the iron body (8) is positioned in relation to the movement path of the element (E) having the permanent magnet (M) such that the force (13) acting on the element (E) in the Detection position (P) is strongest and weakest in the loading position (L). 11. Detector according to claim 4, characterized in that the two-armed pivot lever (9) is at least approximately weight-balanced with respect to the pivot axis (10). 12. Detector according to claim 1, characterized in that an end and laterally open mouth (4) is provided, within which the thread clamping area (6) is located, and that the element (E) within the mouth (4) has an effective length has, thanks to which the element (E), preferably within a limited Swivel range within the mouth prevents the thread from passing the element (E). 13. Detector according to claim 1, characterized in that the element (E) is a in the loading position (L) with the force (13) preloaded spiral spring (18), preferably a leaf spring. 14. Detector according to claim 13, characterized in that the spiral spring (18) is an integral part of a leaf spring (C) for fixing the thread (Y) in the thread clamping area (6) on at least one contact surface (4a). 15. Detector according to claim 14, characterized in that the leaf spring (C) has at least one outer prong, preferably two outer prongs (16, 17) and the spiral spring (18) as a central prong, and that the leaf spring (C) on the housing (3), preferably in the inlet of a mouth (4), is fixed with a bending pretension. 16. A detector according to claim 15, characterized in that the outer tine (16, 17) is wider than the central tine. 17. Detector according to claim 15, characterized in that the spiral spring (18) and the outer tine (16, 17) have different prestresses and / or spring properties. 18. Detector according to claim 17, characterized in that the spiral spring (18) has a constriction (21) in its transition region into the leaf spring (C). 19. Detector according to claim 17, characterized in that the outer prong (16, 17) is flexurally stiffened by at least one longitudinal bead or stiffening structure (25). 20. Detector according to claim 17, characterized in that the outer tine (16, 17) by a e.g. rib-like housing stop (26) is preferably preloaded near the clamping point of the leaf spring (C).