WO2016068722A1

WO2016068722A1 - Hole saw speed coupling

Info

Publication number: WO2016068722A1
Application number: PCT/NO2015/050201
Authority: WO
Inventors: Kai Erland TORGERSEN
Original assignee: Ztools As
Current assignee: Ztools As
Priority date: 2014-10-29
Filing date: 2015-10-27
Publication date: 2016-05-06
Anticipated expiration: 2017-04-29
Also published as: WO2016068716A1

Abstract

Speed coupling for a hole saw comprises an elongate stem (100) with numerous recesses (101, 102, 103, 104) in its surface. A locking device (200) is arranged movable along the stem (100) and comprises a housing (201) with a button bore (205) and a spring at the lower end of the button bore (205). A button (222) is arranged movable within the button bore and exhibiting a stem bore (223) to accommodate the stem (100), and a cam (224) to enable a disengagement of the cam (224) from one of the recesses (101, 102, 103, 104) by depressing the button (220), or re-establish engagement by releasing the pressure on the button (220). The speed coupling further comprises a first tool adapter (300) formed similarly as the locking device (200) and exhibiting a threaded extension (310) as attachment for a hole saw, and optionally a second tool adapter (400). The locking device (200) exhibits posts (202', 203') extending movable through the first tool adapter (300) to engage with apertures in the hole saw to be attached.

Description

Hole saw speed cou

The present invention is related to a hole saw speed coupling. Background

The present invention is related to a speed coupling for hole cutters or hole saws for making holes or or enlarging existing holes in structures, such as walls, ceilings and similar in buildings or other constructions. Tools of this kind are frequently being used in structural engineering, plumbing, electrical engineering and ventilation to make holes of desired diameter or even enlarge existing holes.

For example electricians face a problem when enlarging existing holtes in a ceiling to enable mounting of spotlights with a larger peripheral extension than the existing ones. One way of solving this problem has been to prepare a board with a through hole with the desired new diameter and let one craftsman locate and hold the board with the hole in the desired position while the other craftsman is cutting the hole with a hole saw. Howeover, a disadvantage of this approach is that there is a severe risk of damaging the ceiling and incur more costs. Another disadvantage is that the operation needs two workers, which also adds costs to the operation.

US 2007 166116 A describes a hole cutter of the type mentioned above with a guide for guiding the cutting of holes in a material. An elongate bit portion 102 is provided with stems 114 extending in a longitudinal direction of the bit portion. The stems are arranged to extend through corresponding holes in a first 104 and second 106 hole saw. A drilling portion 110 is also described. While this construction may assist in alleviating the problem mentioned above that involves two craftsmen and involves risk of damaging the structure to be treated, a tool is required to loosen screws 120, 134 to exchange or add/remove hole saw(s). Another disadvantage is that there is no mention of how to remove the plug of cut material.

US Patent 5,226,762 describes a hole-saw arbor for affixing a hole saw to a drill. The arbor comprises a non-cylindrical shaft 12. A drive-boss plate 14 is attached to the drive shaft in an axially, but not rotatably, adjustable relation. The drive-boss plate 14 further comprises two drive bosses 16a and 16b. The drive bosses serve to fix a mounted hole-saw to the shaft 12, powerd by a drill at the opposite end thereof. A drill plate 18 is attached to the shaft 12 by a screw 56 into a bore 58. The drive-boss plate 14 further comprises a releasable locking mechanism in the form of a spring 50 loaded ball 48 accomodated in a notch 42 in the shaft 12. A threaded mounting sleeve 28 is attached to the shaft at its end opposite the "drill" end by a snap ring 65 secured in a groove 62 in thee shaft 12. In an alternative embodiment the drive bosses 16a and 16b serve as ejectors to eject cut material accomodated inside the hole-saw. The mounting end 20 of the shaft is provided with a lock means 24 and 25 to prevent the attached mounting sleeve (and hole-saw) from rotating in a first direction. By turning the drill plate 180 degrees, the lock means prevents the mounting sleeve from rotating in a second direction opposite the first direction. The two locking positions are marked by letters "L" and "T" upon the drill plate 18 to simplify mounting and disconnection of the hole saw.

However, the prior art above has several disadvantages. The drill plate and mounting sleeve allows only one hole saw to be mounted. Moreover, the drill plate has to be turned 180 degrees in one way or the other into a mounting position or disconnecting position when mounting or disconnecting a hole saw. The user must locate the respective positions by inspecting the letters "L" and "T" on the drill plate. Moreover, the drive-boss plate locking mechanism in the form of a spring loaded ball accomodated in the notch in the shaft will allow the drive-boss plate to be released if sufficient force is applied to the drive-boss plate in relation to the shaft. Object

An object of the present invention is to provide a speed coupling for hole saws that enables quick and secure assembly and disassembly of one or more hole saws and optionally bit tools. Another object of the present invention is to provide a speed coupling that overcomes the disadvantages of the prior art. Invention

The object above is achieved by a speed coupling according to claim 1. Further beneficial features appear from the dependent claims.

Unless otherwise is explicitly defined, as used herein, the term "front end" is meant to include the end of the speed coupling facing the saw and cutting tools. Similarly, the term "rear end" is meant to include the end of the speed coupling facing the drilling machine or similar. The term "first end" and "second end" is, unless explicitly defined, also ment to include "front end" and "second end" as defined above.

The speed coupling comprises an elongate centric stem or shaft, with a first end adapted to accommodate a tool assembly and a second end adapted to be inserted into a tool attachment at a drilling machine or similar. The stem comprises at least two recesses or grooves formed in the surface of the stem. The recesses serve as one part of a locking means to engage with the secon part of the locking means arranged in a locking device described in further detail below. The stem further comprises a first tool adapter, which constitutes a part of said tool assembly. The first tool adapter is in its front end provided with an extension with external threads to accommodate a first hole saw. The threaded connection between the tool adapter and the hole saw is based on standards in this field and is not described in further detail.

The locking device, mentioned above, is arranged axially displaceable along the elongate stem providing means to enable a releasable locking engagment with the recesses at pre-selected positions along the stem. The stem extends through a bore in the locking device and a bore in the first tool assembly. Moreover, the locking means is further provided with numerous guiding posts fixed to the locking means and extending in parallell with the stem and having a free end. The guiding posts are arranged, with their free end, to be inserted to and retracted from through axially extending bore(s) in the first tool adapter and apertures in a connected hole saw. Moreover, the locking means is provided with a manual control device that enables the user to release the locking means from engagement with the stem and move the locking means and the accompanying one or more guiding posts along the elongate stem. The guiding posts may also be used for exjecting boring material stuck in or between hole saws by releasing the locking device and moving the locking device with its guiding posts ahead. The stem do preferably exhibit three grooves for parking the locking device in the desired position, where the rearmost groove represents a first position for adding or removing a hole saw at the tool adapter(s), a second position for engaging the posts of the locking device with a first hole saw, and a third position for engaging the posts of the locking device with a second or additional hole saw. It is also conceivable to provide additional grooves in stem. As described in further detail below, the first tool adapter may be formed with a locking mechanism similar to the locking device. In the latter embodiment, the stem also has an additional groove for parking the first tool adapter as well.

The speed coupling according to the present invention may also exhibit a second tool adapter provided with a bore with internal threads for attachment to the treaded portion of the first tool adapter, and one end provided with an externally threaded portion for accomodation of a second hole saw. The second tool adapter also exhibits through bores to accommodate the guiding posts of the locking means.

The first end of the stem may advantageously be provided with a bit reception or bore, known per se, to accommodate a drill bit. The first tool adapter may be formed integrally with the stem, or be provided as a relesable device similar to the locking device. In the latter embodiment, the first tool adapter may be inserted onto the stem and interlocked with the stem in a fixed position by a control means similar to the control means of the locking device. An embodiment of the control means and the engagement with the stem is examplified in the detailed description below.

In use, the operator may insert the second end of the stem, of an assembled cpeed coupling, into the tool attachment of the drilling machine. Then, the user operates the control means of the locking device, and slides the locking device along the stem towards said second end of the stem and the adjacent drilling machine. There, the operator locks the locking device in a first locking position along the stem by establishing engagement between the locking device and a first groove or recess formed in the perifery of the stem. In this position, the post(s) of the locking device have been retracted from the front surface of the first tool assembly housing and into axially extending post bore(s), thus exposing the externally threaded end of the first tool adapter. Then, the user screws a first hole saw onto the treaded portion of said first tool adapter. If a second hole saw is to be attached, the user may screw the second hole saw onto the threaded end of the first tool adapter, or attach a second tool adapter by screwing it onto the externally threaded portion of the first tool adapter, whereupon a second hole saw, having a smaller diameter than the first hole saw, is screwed onto the externally threaded portion of the second tool adapter. A third tool adapter, similar to the second adapter, may also be provided, which in a similar may be attached to the second tool adapter adjacent to the second hole saw, to accommodate a third hole saw with a smaller diameter than the second hole saw. A drill bit may optionally be inserted into the bit reception in the first end of the centric stem. Finally, the user operates the control means of the locking device to release its engagement with the stem, moves the locking device forward along the stem to a locking position on the stem, releases the control means to reestablish engagement between the locking device and another recess or groove formed in the peripheral surface of the stem. In this interlocking position of the locking device and the stem, the guiding posts of the locking device have been forwarded through the post bores of the first tool adapter and through similar holes provided in the hole saws mounted to the speed coupling. In this position, the hole saws and optionally the drill bit are fixed securely to the speed coupling and the tool is ready for use. The hole saws and optionally the drill bit will rotate with the stem powered by a drill machine or similar.

The speed coupling in accordance with the invention for hole saws exhibits a substantial advantage in that hole saws may be assembled or disassembled in a fast and safe manner that has been unattainable until now. The locking mechanism ensure a safe locking of the locking device and tool adapter to the stem, preventing any axial movement of the stem. Moreover, the tool adapters emables mounting of several hole saws to improve drilling efficiency. In a preferred embodiment described in further detail below, the housing of the locking device and/or the tool adapters are formed with cut-outs and control buttons having an extension in the radial direction (of the stem) that is longer than the extension in the axial direction. The speed coupling of the present invention may also be used to remove cut material from the space inside the hole saws by advancing the locking device and its guiding posts further and into the cut material to eject the same from the hole saw. Detailed description

The invention is in the following described in further detail by an example of an embodiment and with reference to drawings, where similar numeral references have been used to identify similar components of the speed coupling. In the drawings,

Fig. la illustrates a top view of a first embodiment of the speed coupling according to the invention in an assembled state but without connected tools and drilling machine,

Fig. lb is a drawing of the speed coupling of Fig. la viewed in perspective from above,

Fig. 2 illustrates a cross section the assembled speed coupling along the line 2-2 in Fig. la,

Fig. 3a-3d show the housing component of the loking device in different views,

Fig. 4a-4d show the button component of the locking device to be inserted into a bore in the housing part of Fig. 3a-3d, and

Fig. 5 is a drawing similar to Fig. lb, illustrating a preferred second embodiment.

Now referring to Fig. la and lb, the first embodiment of the speed coupling comprises an elongate (centric) stem or shaft 100 with a hexagonal cross-section and having a first end 105 (front end, best viewed in Fig. 2) and a second end 106 (rear end). The stem 100 is provided with at least one first peripheral recess 101 adjacent to the second (rear) end 106 of the stem and a second recess 102 displaced at a distance from the first recess 102 in a direction towards the first (front) end 105 of the stem 100. The respective recesses 101 and 102 are arranged to establish a releasable engagement with a locking device 200 (described in further detail below). The locking device 200 comprises a housing 201, a spring-loaded depressable button 220 accomodated in a button bore 205 in the housing 201, movable (depressable) in a radial direction in view of the longitudinal axis L of the stem 100. The button 220 represents one embodiment of the control means, described in further detail below. Moreover, a first and second elongate guiding post 202' and 203', respectively, having a circular cross-section, are attched to the front end 206 of the housing 201 and with their free ends 202', 203', respectively, extending through post bores 302, 303 (indicated in Fig. lb) formed in a first tool adapter 300.

In Figs, la and lb, the free ends 202" and 203" of the posts 202', 203', respectively, projects out of the surface of the first tool adapter 300 at a front end 306 (Figs, lb and 2) of the latter. Moreover, the first tool adapter 300 is provided with an externally threaded extension 310 to accommodate a first hole saw (not shown), the hole saw being provided with a central threaded hole to engage with the externally threaded extension 310 of the first tool adapter 300. At the transition between the housing 301 and the threaded extension 310, at the front end of the housing 301, it is provided a recess 311 to accommodate a gasket, packer or similar (not shown). This packer is advantageously included to simplify disassembly of a hole saw from the threaded extension 310 and the adjacent housing 301. Moreover, two post bores 302, 303 are arranged to accommodate the guiding posts 202', 203' of the locking device 200. The externally threaded extension 310 of the first tool adapter 300 is advantegously formed with a drill bit bore 309 (Fig. 2) to allow insertion of a drill bit (not shown) through the bore 309 and into the first end 105 of the stem 100 in a manner known per se.

In this embodiment of the present invention, also the first tool adapter 300 is arranged to be releasably attached to the stem 100 by means of a locking device arrangement similar to the locking device 200 and its interengaging recess 101 in the stem. The control device of the first tool adapter 300 does also comprise a housing 301 and a control device 320, but with the threaded extension 310 extending towards the front end of the assembly. However, the remaining construction may adavantageously be similar in construction and function as the locking device 200. A detailed description of the lock and release mechanism of the first tool adapter 300 is therefore omitted from this description.

The attachment apertures of the hole saw itself, is in this embodiment formed with diameters and locations in accordance with standards, and is therefore not described in further detail here as it will be apparent to one skilled in the art. Figs, la and lb also show a second tool adapter 400 arranged to accommodate a second hole saw (not shown), described in further detail below. The second tool adapter 400 is provided with a housing 401 formed with an internally threaded central bore 404 to accommodate the externally threaded extension 310 of the first tool adapter 300. As with the first tool adapter 300, the second tool adapter housing 401 is provided with an externally threaded hollow extension 410 for attachment of the second hole saw. The external diameter of the extension 410 of the second tool adapter 400 may advantageously be smaller than the external diameter of the extension 310 of the first tool adapter 300 to allow assembly of a second hole saw with smaller saw diameter. Moreover, the extension 410 is advantageously formed with a central bore to enable insertion of a drill bit (not shown) or similar through the bore 404, and the drill bit bore 309 (Fig. 2) of the first tool adapter 300, and into the first end 105 of the stem 100 as described above. Similar to the first tool adapter 300, the housing 401 of the second tool adapter 400 is provided with a first 402 and second post bore 403 formed to accommodate the first 202' and second 203' guiding post of the locking device 200. The second tool adapter 400 is also advantageously formed with a recess to accommodate a packer, gasket or similar (not illustrated), similar to the recess 311 of the first tool adapter 300.

Accordingly, Figs, la and lb illustrate an embodiment of the speed coupling of the present invention in an assembled state where the hole saw(s), drill bit and drilling machine have been omitted for clarity sake. The housing part 201 of the locking device 200 shown in la, lb and 2, is illustatred in further detail in Figs. 3a-3d, where Fig. 3a is a perspective view of the housing seen from above, Fig. 3b is a side view of the (front end) of the housing, Fig. 3c is an end view of the housing, whereas Fig. 3d is a cross-section taken along the line 3d-3d of Fig. 3c. The housing 201 comprises a first post bore 202 and a second post bore 203 extending axially and in parallell with a longitudinal axis of the stem 100 in an assembled configuration. The post bores 202 and 203 are provided to accommodate the first post 202' and second post 202", respectively, in a fixed manner. The posts may for example be welded or glued to the housing 201, or fastened by threads or other means.

Moreover, still referring to Figs. 3a-3d, the housing 201 exhibits a button bore 205 extending (radially in view of the longitudinal axis of the stem 100 in an assembled configuration) from a top surface and with a closed bottom 208 to accommodate a spring (not shown) to interact with a bottom part 225 of the button 220 when inserted into the button bore 205. The housing is also provided with a hexagonal through stem bore 204 to allow accomodation of the hexagonal stem 100 in a slidable manner. A pin bore 207 is formed in the housing 201 to accommodate a locking pin (not shown) to restrict radial movement of the button 220 in relation to the housing 201 (described in further detail below in connection with Fig. 4a-4d). Instead of a closed bottom 208, the button bore 205 may be through with a land surface at the bottom to support the spring within the bottom 208 of the button bore 205. The button part 220 of the locking device 200 shown in la, lb and 2 is illustatred in further detail in Figs. 4a-4d, where Fig. 4a is a perspective view of the button 220 slightly from above, Fig. 4b is a side view of the of the button 220, Fig. 4c is another side view of the button taken from a side view 90 degrees of the one in Fig. 4c, whereas Fig. 4d is a cross-section taken along the line 4d-4d of Fig. 4c. In the illustrated embodiment, the button 220 exhibits a substantially cylindrical shape and is indicated with its upper surface 221 that in an assembled configuration is exposed outside the housing 201 to interact with the user's finger. The lower surface of the button 220 is indicated at 225. In an assembled configuration, the button 220 is inserted into the button bore 205 of the housing 201, leaving a free space 208 in the closed bottom of the button bore 205 in the housing 201 (Figs. 2 and 3d). The button 220 is further provided with a through stem bore 223 having cross section that allows for accomodation of the stem 100 and a certain radial movement of the button 200 in relation to the stem 100. A notch 222 is formed in a side surface of the button 220 to accommodate a locking pin (not shown) inserted into the pin bore 207 in the housing 201 and within the notch 222. Thus, the locking pin will restrict radial movement (to the longitudinal axis of the stem 100 in an assembled configuration) between an upper notch end 222a and lower notch end 222b of the button 220, and prevent the button from being ejected out of the button bore 205 by the spring (not shown) accomodated in the free space 208 in the bottom of the button bore 205 in the housing 201 (Fig. 2, 3d). At the bottom of the stem bore 223, a lug or cam 224 is formed integrally with the button 221. The cam 224 has an extension (in the cross-section as shown in Fig. 4d) that allows insertion into any one of the recesses 101, 102, 103 and 104 in the periphery of the stem 100 (Figs, la, lb and 2).

As mentioned above, the first tool adapter 300 is in this embodiment designed in a similar manner as the locking element 200, except that the first tool adapter 300 at its front end is provided with a threaded extension 310. The threaded extension 310 may be formed integral with the housing 310 of the first tool adapter 300, or be attached releasably, such as by means of threads (not shown). The remaining parts in the form of housing 301, button 320 and their respective detailed components are similar to the components comprised by the housing 201 and button 220 of the locking device. The similar components of the first tool adapter 300 have been assigned a similar numeral reference as the locking device 200, where the components of the first tool adapter is prefixed with the digit 3. Accordingly, button 222 corresponds to button 320, cam 224 corresponds to cam 324, pin bore 207 corresponds to pin bore 307 and so on.

Fig. 2, which is a cross-section taken along the line 2-2 in Fig. la, illustrating the assembly in a locked configuration. Cam 224 of locking device 200 is in engagement with recess 102 of stem 100 and cam 324 of first tool adapter 300 is in engagement with recess 104 of stem 100. Buttons 220 and 320 do, with their upper surface 221, 321, project slightly above the surface of housings 201 and 301, respectively. Free space 208 and 308 are left between the (closed) bottom of the housings 200 and 300 and the bottom end 225, 325 of the buttons 220 and 320, respectively. A spring (not shown) located within free space 208, 308, forces the button with its cam upwards into a locking engagement between cam 224 and recess 102, and between cam 324 and recess 104. In order to release the engagement between locking device 200 and stem 100, or between first tool adapter 300 and stem 100, the operator depressess button 220 or 320 to bring cam 224 or cam 324 out of engagement with the respective recess in stem 100, whereupon the locking device 200 or first tool adapter may be moved along stem 100 into a new position along stem 100.

The second tool adapter 400 may be exchanged by a cutting adapter (not illustrated), i.e., an adapter formed similar to the second tool adapter 400 as illustrated, but provided with cutting edges. In a configuration with one or more (concentric) hole saws attached to the threaded end 310, a cutting adapter may be connected to the threaded end 310 with said cutting edges located within the internal cavity of the (innermost) hole saw. This configuration will enable cutting of material into smaller fragments and simplify removal of cut material from the hole saw. This is particularly advantageous where an operator is cutting a deep hole and has to retract the saw from the hole being cut several times to remove cut material therefrom, and proceed with the cutting operation until the desired depth has been reached.

Fig. 5 illustrates a preferred second embodiment of the speed coupling of the present invention. Here the stem 100 is provided with a hollow core indicated at reference numeral 107. The locking device housing 201 tool adapter housing 301 are provided with a shorter axial extension. The buttons 320 accomodated in the locking device 200 and tool adapter 300 are provided with an ellipcital periphery. The remaining parts of the button and their accomodating bores 205 and 305 in the housings are similar to the first embodiment, as illustrated in Figs. 3a-d and 4a-d. Moreover, one or more parts of the locking device housing 201 is provided with a cut-out, indicated by reference numeral 215 at the (lower) side parts of the housing 201. A similar cut-out is provided in the tool adapter housing 301, indicated at reference numeral 315. The step 100 is provided with another recess in its periphery (not illustrated), thus providing a further position for the locking device 200 along the stem 100.

In addition to the extra recess in the stem, the second embodiment shown in Fig. 5 exhibits lower weight than the first embodiment. The reduced weight offers lower transportation cost and simplifies handling during use.

Assembly

The assmembly of the speed coupling according to the embodiment described above proceeds substantially as follows: a spring is inserted into the button bore 205 and seated in the bottom end of the button bore 205. Then a button 220 is inserted into the button bore 205 of the housing 201 and the button is located with its notch 222 facing the pin bore 207 (which is partly exposed to the button bore 205). A locking pin (not shown) is inserted into the pin bore to allow a restricted radial movement of the button 222 in the button bore 205, where the locking pin abuts with the upper notch end 222a when the button is fully depressed. When the button is released, the locking pin abuts with the lower notch end 222b in virtue of the spring acting upon the button. In this confiuration the spring (not shown) is located in the free space 208 between the bottom end of the button bore 205 and the underside of the button 220, exterting a force upon the button in a direction out of the button bore 205.

Then, the a stem 100 is provided, and the user depresses the button 220 of the locking device 200 down towards the spring and inserts the stem 100 with its second end 106 through the stem bore 204 of the housing 201 and through the stem bore 223 of the button, until the locking device 200 reaches the first recess 101 in the stem 100. Then, the user releases the button 220 whereupon the spring forces the button 220 in a direction out of the button bore 205 of the housing 201, whereupon the cam 224 is inserted and landed in the recess 101. The locking device 200 is in this configuration in a locked engagement with the stem 100.

Then, a first tool adapter 300 is provided. Its construction is in this embodiment similar to the locking device, except from the threaded end 310. The stem 100 is, in a manner similar to the locking device 200 above, inserted with its first stem end 105 into the stem bore 304 of the first tool adapter 300, until it reaces the last recess 104 of the stem 100, whereupon the button 320 is relased to bring the first tool adapter 300 in a locked engagement with the stem 100. This configuration is illustrated in Fig. 2. Modifications

Whereas the embodiment of the present invention has been described with structure details related to prevailing standards within this technical field, it should be evident that the present invention examplified above easily may be adapted to any different standards as well, without departing from the inventive idea. Thus, the central stem may exhibit a different cross-section than hexagonal, e.g. triangular, square, polygonal, circular with radially extending grooves or tongues. Moreover, the locking device examplified with two guiding stems above may exhibit a different number of guiding stems, such as three or four. The locking device examplified above realized in the form of a spring loaded press button accomodated movable within a locking housing to engage or disengage a groove, formed in the periphery of the stem, in relation to a lug formed in the press button, may be provided in another form of a fast acting mechanical locking principle. The speed coupling is advantageously formed of stainless steel. However, other materials may also be conceivable provided that the construction withstands the torque exerted by the drilling operation. The present disclosure does not include any dimensions or mutual dimensions between elements therein. However, several structural elements are formed in accordance with standard dimensions for equipment of this type. Accordingly, these and other modifications will be within the reach of a person skilled in the art when taking the present dosclosure into consideration. The depressable buttons 220 and 320 are illustrated with a circular and elliptical cross-section in the first and second embodiment. However, these are only examples and other geometries are conveivable as well, e.g. square.

Claims

1. Speed coupling for a hole saw to enable assembly of one or more hole saws, and optionally a drill bit, to a drilling machine, said speed coupling comprising: an elongate stem (100), with a front end (105) facing said one or more hole saws, a rear end (106) for attachment to the drilling machine, and a longitudinal axis (L), at least one tool adapter (300) exhibiting a housing (301), a stem bore (304) accommodating said stem (100) in a slideable manner along the longitudinal axis (L), at the front end (105) of the stem, said tool adapter (300) having an extension (310) at its front end with external threads for attachment of a hole saw, a locking device (200) exhibiting a housing (201), a stem bore (204) accommodating said stem (100) in a slideable manner along the longitudinal axis (L), movable between the rear end (106) and the tool adapter (300), wherein the locking device (200) further comprises guiding posts (202', 203') extending in parallel with the stem (100) and having a free end (202", 203") extending through guiding bores (302, 303) and for engagement with apertures in the hole saw,coupling characterized in that: said stem (100) exhibits two or more peripheral recesses (101, 102, 103, 104) in its surface, and that the locking device (200) exhibits a control button (220) arranged movable in a button bore (205) in the housing (201), substantially radially to the longitudinal axis of the stem (100), - from a locked configuration where a protrusion (224) at the control button (220) is in engagement with one of the recesses (101, 102, 103, 104) in the stem (100), thus in a locked position preventing axial movement of the locking device (200) along the stem (100), and

- to a released configuration where the control button (220) is able to move radially and bring the protrusion (224) out of engagement with the recess (101, 102, 103, 104) to enable the locking device (200) together with its guiding posts (202', 203') to be moved along the stem

(100).

2. The speed coupling of claim 1, characterized in that the control button exhibits an upper surface (221) exposed outside the housing (201) to interact with the user's finger, and a lower surface (225), a through stem bore (223) to accommodate the stem (100) and to allow a limited radial movement of the button (220) within the stem bore (223), said protrusion (224) being arranged within the stem bore (223), and restriction means (222) to restrict said radial movement of the button (220).

3. The speed coupling of claim 2, characterized in that a spring member is arranged in a free space (208) in the button bore (205), at a lower surface (225) of the button (220), applying a spring force to the lower surface (225) of the button (220), said housing (201) and button (220) exhibiting a restriction means (207, 222) to prevent the button from being ejected from the button bore (205) by the spring member.

4. The speed coupling of any on of the preceding claims, characterized in that the first tool adapter (300) exhibits a housing (301) with a radially extending button bore (305) with a closed end, a spring member arranged at the closed end of the button bore (305), a button (320) arranged slideably in the button bore (305) above the spring member and exhibiting a stem bore (323) with a diameter larger than the diameter of the stem (100), said housing (301) and button (320) exhibiting a restriction means (307, 322) to prevent the button from being ejected from the control button bore (205) by the spring member.

5. The speed coupling of claim 2 or 4, characterized in that the restriction means comprises a notch (222; 322) formed in the surface of the button (220; 320), a pin located in a pin bore (207; 307) in the housing (201; 301) and extending through the notch (222; 322), thus restricting movement of the button (220; 320) in the button bore (205; 305) between an upper end (222a) of the notch and a lower end (222b) of the notch.

6. The speed coupling of claim 1, characterized in that the first tool adapter (300) at a transition between the housing (301) and the threaded extension (310), exhibits a recess (311) for accommodation of a gasket.

7. The speed coupling of claim 1, characterized in comprising a second tool adapter (400) having a housing (401), post bores (402, 403) for accommodation of guiding posts (202', 203'), an externally threaded extension (410) for attachment of hole saws, and an internally threaded stem bore (404) for attachment to the externally threaded extension (310) of the first tool adapter (300).

8. The speed coupling of claim 1, characterized in comprising a cutting tool adapter (400) having a housing (401), post bores (402, 403) for accommodation of guiding posts (202', 203'), an externally threaded extension (410) for attachment to hole saws, and an internally threaded stem bore (404) for attachment of the externally threaded extension (310) of the first tool adapter (300), whereby the cutting tool adapter is provided with cutting edges.

9. The speed coupling of any one of the claims 1 to 8, characterized in that the locking device housing (201) is provided with one or more cut-outs (215).

10. The speed coupling of any one of the claims 1 to 8, characterized in that the tool adapter housing (301) is provided with one or more cut-outs (315).