WO2012110453A1

WO2012110453A1 - Torque transmission device in the form of a bit chuck

Info

Publication number: WO2012110453A1
Application number: PCT/EP2012/052406
Authority: WO
Inventors: Oliver Pistor
Original assignee: Wera - Werk Hermann Werner Gmbh & Co. Kg
Priority date: 2011-02-14
Filing date: 2012-02-13
Publication date: 2012-08-23
Also published as: DE102011000710A1

Abstract

The invention relates to a torque transmission device (1) comprising a drive shaft (2), which can be inserted into a chuck (8) of a rotational driving device and is fitted in an inner sleeve (10), which has an insert opening (3) intended for receiving a screwdriver insert (9) and formed such that the profiled working tip (15) of the screwdriver insert (9) inserted into the insert opening (3) protrudes beyond the periphery (12) of the insert opening (3), and comprising an outer sleeve (11), which can be moved back and forth in a stop-limited manner on the inner sleeve (10), between a first stop position, in which a rear stop (16) of the outer sleeve (11) lies against a rear counter-stop (17) of the inner sleeve (10) and a toroidal magnet (13) fixedly connected to the outer sleeve (11) lies at a distance ahead of the periphery (12) of the insert opening (3), and a second stop position, in which the toroidal magnet (13) lies against the periphery (12) of the insert opening (3). For functionally advantageous development, in particular for use on impact wrenches, it is proposed that the outer sleeve (11) is held in the second stop position by a magnetic force of attraction of the toroidal magnet (13), which has to be overcome to move the outer sleeve (11) in the direction of the first stop position by applying a pulling force to the outer sleeve (11).

Description

Torque transmission device in the form of a bit lining

The invention relates to a torque transmission device, in particular in the form of a quick change chuck for a screwdriver bit, with a insertable into a chuck of a rotary drive device drive shaft inserted in an inner sleeve having an insertion opening for receiving a screwdriver bit, which is formed so that the profiled working tip of the protruding into the insertion opening screwdriver bit beyond the edge of the insertion, and with an outer sleeve, the stop limited to the inner sleeve between a first stop position in which a first drive shaft side stop of the outer sleeve rests against a first counter-stop of the inner sleeve and a fixed to the outer sleeve Ring magnet is located at a distance from the edge of the insertion, and a second stop position, in which the ring magnet rests on the edge of the insertion, back and forth is displaceable.

The EP 1 260 319 Bl describes a generic torque transmitting device in the form of a quick change chuck for Schraubendreherbits, wherein in a inner sleeve, a hex shank is clamped, which protrudes from the inner sleeve section forms a clamping portion with which the shaft can be inserted into a chuck of a drive unit. The inner sleeve is made of a non-ferromagnetic material and surrounded by a likewise made of a non-ferromagnetic material outer sleeve which carries on its side facing away from the drive portion side a ring magnet which can be brought by moving the outer sleeve against the surrounding a Schraubwerkzeugeintrittsöffnung end face of a screw head, so as to fix the screw in alignment with the axis of rotation of the chuck. DE 20 2009 015 665 U1 likewise describes a generic bit lining in which an inner sleeve has an insertion opening for a screwdriver bit and an opposite opening in which there is a drive shaft. On this inner sleeve, an outer sleeve is slidably mounted, the front edge carries a magnet. In order to keep the outer sleeve in the different positions, a spring-loaded ball or a spring-loaded friction piece, which is frictionally supported on the inner side of the outer sleeve, is inserted in a bore of the inner sleeve extending transversely to the direction of rotation.

The DE 20 2009 014 890 Ul describes a quick-change chuck with outer sleeve with ring magnet, which is held by a tensioned spring in a stop position. A similarly designed adapter describes the DE 20 2008 011 143 Ul.

From EP 0 988 134 Bl a quick-change chuck with a torsion zone is known, which acts as an energy storage to take in hard screw torque peaks. DE 10 2005 048 345 A1, DE 20 2006 014 850 U1, EP 2 140 976 A1 or EP 2 140 977 A1 or EP 2 140 978 A1 describe so-called impact wrenches which have a rotary impact mechanism. Such rotary impact wrenches have been known on the market for several years. The impact wrenches have a rotary blower, which is able to temporarily store the driving energy of a motor of the impact wrench in the form of pulses and to transmit this energy periodically within very short working phases to a rotationally driven by an output shaft chuck. In such a chuck, a bit holder can be inserted. In the insertion of the bit holder, a screwdriver bit can be inserted, as described for example by WO 2010/054169 AI. The periodically on the screwdriver Herbit generated angular momentum generate very high torque peaks depending on the pulse duration. Depending on the design of the rotary impact wrench, the torque peaks can reach up to 180 Nm or even more than 200 Nm. Depending on the design and / or operating mode, rotary impact wrenches work with 1500 or 2700 beats per minute.

The invention has for its object to further develop a generic torque transmitting device nutzsvorteilhaft and in particular for use on impact wrenches.

The object is achieved by the invention specified in the claims.

First and essentially it is provided that the outer sleeve is held by a magnetic attraction of the ring magnet in the second, that is retracted stop position. Unlike the prior art, this attraction must be overcome in order to displace the outer sleeve from this stop position in the direction of the first stop position or to separate the ring magnet from the opening edge of the insertion. If this attraction is overcome, then the ring magnet can be brought into an abutment position against the end face of the head of a screw in the Schraubwerkzeugeingriffsöffnung the working tip of the screwdriver bit inserted. The inner magnet is then held on the screw head due to its magnetic attraction. The torque transmission device according to the invention in the form of a quick-change feed can also be used in an operating position in which the outer sleeve is held by the magnetic attraction in a distance position to the screw head and the magnet in an abutment position at the opening edge. This operating position is retained even when the quick-change chuck is driven by a rotary impact driver. Although the

Rotary impact driver considerable vibration on the torque transmission transmits transmission device, the outer sleeve remains in the inactivated, ie retracted position in which the ring magnet rests on the edge of the insertion. In a preferred development of the invention, an energy store is arranged between a drive section of the drive shaft, which can be inserted into the chuck of a rotary impact wrench, and an output section, which is formed by the insertion opening. When applying a torque and a rotation of the drive section relative to the output section, this energy store can rotate by a twist angle. The energy store charges up. The energy store can also be dimensioned so that the introduced in the form of rotational shocks via the drive section in the energy storage rotational pulses are such temporally stretched or attenuated delivered via the output section that the torque peaks of the emitted energy pulses are below the static breaking torque of the respective Schraubwerkzeugarbeitsspitze. As a result, the life of both the chuck and the screwdriver bit increases. If a quick-change chuck formed with such a torsion zone is used on a rotary impact driver and the outer sleeve assumes its operating position, in which the ring magnet bears against the end face of a screw head in order to keep the screw in alignment with the axis of rotation, the impacts or vibrations cause it the outer sleeve vibrates in the direction of displacement, whereby the magnet releases from the contact position on the screw head. The vibrations are damped by the torsion zone in such a way that the outer sleeve is always displaced back into the contact position of the magnet against the end face of the screw head, in particular by the force of the magnet. The torsion zone and the strength of the ring magnet are coordinated so that the vibrations during screwing with a rotary impact driver only slight spacings of the ring magnet from the front side of the screw effect benkopfes. The spacing of the ring magnet is never greater than the attraction region of the ring magnet, so that the magnetic attraction always leads to a shift back of the ring magnet in the contact position on the screw head. On the other hand, if the torsion zone is too small or does not exist at all, it can lead to a rapid breakage of the screw insert and cause the outer sleeve to jump off the screw head so far that the ring magnet strikes against the edge of the insertion opening, with the result that the outer sleeve remains fixed in this stop position. If a breakage of the screwdriver set occurs now, splinters may loosen and damage the workpiece. As a consequence of the torsion zone, however, the outer sleeve remains permanently in its contact position, except for sporadic detachments of low lift, in which the ring magnet is pulled against the end face of the screw head. The outer sleeve thus forms a splinter protection in the activated position.

The assembly of the torque transmitting device is simple, since the rear stop is formed by a sleeve inner stage of the outer sleeve and a counter-stop corresponding thereto from an outer ring stage of the inner sleeve. For mounting, the outer sleeve, which is initially not yet provided with the ring magnet, is passed over the clamping section of the

Drive shaft slipped up until the rear stop abuts the counter-stop. In the edge of the insertion projecting end of the outer sleeve of the ring magnet is then inserted. The ring magnet can be pressed into a press-fit opening whose inner diameter is smaller than the outer diameter of the inner sleeve. The attachment of the ring magnet at the end of the outer sleeve can also be done via a flanging. Likewise, it is provided that the ring magnet is glued into an opening of the outer sleeve. The connection between the ring magnet and the outer sleeve can thus take place in a form-fitting, non-positive or material-locking manner. The magnet then also forms a stop. In a preferred development of the invention, it is provided that the energy store formed by the torsion zone is arranged inside the inner sleeve. The energy store is located between two hexagonal sections, with a shaft end side hexagonal section inserted in the inner sleeve in a rotationally and axially fixed manner. The other hexagonal section extends through a hexagon opening of the inner sleeve with a stop-limited rotary motion clearance. It may be provided outside the inner sleeve, a second torsion zone. The inner sleeve, but also the outer sleeve can be made of a ferromagnetic material see. However, it is sufficient if only the edge portion of the insertion consists of a ferromagnetic material or even magnetic, so that the ring magnet is held by magnetic attraction in its stop position at the opening edge. This power of attraction can only be overcome by intentionally pulling on the outer sleeve. This tensile force is greater than the maximum inertial forces due to vibration when screwing with a rotary impact driver.

The invention further relates to the use of a torque transmitting device, as has been previously described with a

Rotary impact wrench, as described in the introduction, which thus has a motor that operates a rotary blower, so that transferred to a coupled to the drive section feed at least 1000 strikes per minute, each rotary impact a peak torque of at least 60 Nm, preferably at least 75 Nm having. In use inserted in the insertion a screwdriver bit with a non-circular output profile for entry into a Schraubwerkzeugeintrittsöffnung a screw.

An embodiment of the invention will be explained below with reference to accompanying drawings. Show it: 1 is a side view of a torque transfer device in the form of a quick-change chuck for screwdriver bits. Figure 2 is a section along the line II - II, wherein the ring magnet 13 abuts in an abutment position on the opening edge 12 of the insertion opening 3.

2, but with the ring magnet 13 removed from the opening edge 12, wherein the working tip 15 of the screwdriver bit 9 in a screwing tool inlet opening 22 of FIG

Screw head 21 of a screw 20 is inserted and the outwardly facing end face 13 "of the ring magnet 13 rests against the end face of the screw head 21. Fig. 4 is an exploded view of the torque transmitting device;

Fig. 5 shows the use of the torque transmitting device with a percussion screwdriver, wherein the outer sleeve 11 assumes its inactive rearward position and

6 shows an enlarged section, partially broken away, of the region in FIG. 5 in which the working tip 15 engages the screw head 21, but with the outer sleeve 11 displaced in the direction of the screw head, the annular magnet 13 being at a distance from the screw head 21, FIG. by standing in such a magnetic attraction to the screw head 21, that the outer sleeve 11 is brought by the magnetic force into an abutment position of the end face 13 "on the front side of the screw head 21. The torque transmission device 1 has a drive shaft 2, which forms a polygonal section 28 at one end, which press-fits into a reduced-diameter section of a cavity of an inner sleeve 10. The end face 26 of this polygonal section 28 forms the bottom of a polygonal cross-section insertion opening 3 for receiving the hexagonal portion 14 of a screwdriver bit. 9

The polygonal section 28 is followed by a diameter-reduced torsion section 4, the length of which may be between 10 mm and 15 mm and whose diameter is less than 6 mm. The material hardness of the torsion zone 4 is in the range between 44 HRC and 62 HRC.

The torsion section 4 is adjoined by a further polygonal section 18 which, with a slight rotational play, inserts into a polygonal polygonal opening 19 of the inner sleeve 10 with a larger diameter.

At this polygonal section 18 is followed by a lying outside the inner sleeve 10 second torsion zone 24, which has a larger diameter than the torsion 4. The free end of the drive shaft 2, which is also polygonal, forms a drive section, which feeds into a drive machine can be inserted.

All aforementioned polygonal sections are hexagonal sections in the embodiment.

Rearward of the opening edge 12 of the insertion opening 3 is in a recessed groove a retaining ring 25 to hold the screwdriver bit 9 in the insertion opening 3 frictionally. From the side of the drive portion of the drive shaft 2 ago an outer sleeve 11 is pushed over the inner sleeve 10. The outer sleeve 11 forms an annular stop shoulder 16, which can interact with an annular counter stop shoulder 17 of the outer wall of the inner sleeve 10. The outer sleeve 11 can thus only be pushed so far in the direction of the screwdriver bit 9 on the inner sleeve 10 until the annular shoulder 16 abuts against the annular shoulder 17. In this stop position, which is not shown in the figures, has a pressed-in an inlet opening 23 magnet 13 a maximum distance from the opening edge 12. An end face 13 "of the magnet 13 forms an end face of the outer sleeve 11. The inwardly facing end face 13 ' of the ring magnet 13 forms a stop surface which rests against the opening edge 12 in an inactive position of the outer sleeve 11.

Since at least the portion of the inner sleeve 10 forming the opening edge 12 is made of a ferromagnetic material, a magnetic attraction acts between the magnet 13 and the opening edge 12. Preferably, the entire inner sleeve 10 is made of a ferromagnetic material.

The outer sleeve 11 is also preferably made of a ferromagnetic material and has on its outer side a wide diameter-reduced zone in which a labeling sleeve 30 is located.

A bit inserted in the insertion opening 3 has a profiled drive tip 15, which can be profiled for engagement in a cross-slot profile, in a Torx profile or the like. This work tip 15 projects beyond not only the opening edge 12, but also the end face 13 "of the outer sleeve 11 when it is in the inactive position (see Figure 2).

If a screw is to be screwed into a workpiece with the quick-change chuck 1 using a screwdriver set 9, then Inserting a tensile force, for example by manual attack on the lateral surface of the outer sleeve 11 of the ring magnet 13 is inserted from the opening edge in the insertion opening 3, the hexagonal portion 14 of the matching bit and the working tip 15 of the bit in the Schraubwerkzeugeinstecköff- 22 of the screw head 12 separated by the magnetic attraction is overcome. This is done willfully. The outer sleeve 11 can now be displaced in the direction of the working tip 15 in the axial direction of the torque transmission device 1 until the end face 13 "bears against the surface section of the end face of the screw head 21 surrounding the screwing tool inlet opening 22. The direction of extension of the screw 20 thereby becomes tangential the extension direction of the torque transmission device 1 centered.

In a hard screwing, which occurs when a screw with metric thread is screwed into an internal thread, for example, a metallic workpiece as soon as the screw head touches the workpiece surface, occurs a high torque peak, as the rotational movement is abruptly decelerated. This torque peak can be extended in time, since the torsion zone 4 is slightly twisted. Preferably, the maximum angle of rotation is limited to an axial shear angle of at most 2 °. This restriction can be dimensioned via a suitable choice of the play-loaded hexagonal handle 18, 19.

FIG. 5 shows a preferred mode of use of the torque transmission device 1 according to the invention in combination with a

Rotary impact wrench, which has a drive unit 5, in which a drive motor 6 is located, which drives a rotary blower 7, which is over 1000 Turns per minute on a chuck 8 transmits. In the chuck 8, the drive portion of the drive shaft 2 is clamped.

If the chuck is to be operated with the outer sleeve 11 inactivated, as shown in FIG. 5, the rotational strokes and the associated vibrations do not cause the outer sleeve 11 to shift. The magnetic attraction of the magnet 13 at the opening edge 12 prevents the outer sleeve 11 from moving. If, on the other hand, the lining is to be used in the operating position shown in FIG. 3, in which the end edge 13 "of the outer sleeve 11 rests against the screw head 21, then the torsion zone 4 causes such a temporal extension of the rotational shocks that the vibrations possibly lead to the outer sleeve 11 is slightly displaced away from the screw head 21. However, the displacement distance is not greater than the attraction area of the ring magnet 13, so that the outer sleeve 11 remains in the spacing position only for a very short time before being returned to the screw head 21 from the ring magnet 13 As a result, the outer sleeve 11 also has a splinter protection function in combination with a rotary impact drive tool, with such a slight spacing being shown in FIG.

The outer sleeve 11 not only forms a centering aid to allow the one-handed screwing a screw. The outer sleeve 11 forms a splinter contactor, in particular in the final phase of screwing in a wood screw. When screwing in a wood screw, the torque to be applied to the screw increases as the depth of engagement of the screw in the workpiece increases. Accordingly, high torque peaks are applied to the screwdriver bit 9, especially in the final phase of screwing. Although these torque peaks are damped by the two torsion zones 4 and 24. But it can happen that the Screwdriver bit 9 breaks. Because of the vibration-damping effect of the torsion zone 4, the outer sleeve 11 forms a nearly permanent splinter protection, so that in the case of a bit break the lateral throwing away of splinters is avoided.

All disclosed features are essential to the invention. The disclosure of the associated / attached priority documents (copy of the prior application) is hereby also incorporated in full in the disclosure of the application, also for the purpose of including features of these documents in claims of the present application. The subclaims characterize in their optional sibling version independent inventive development of the prior art, in particular to make on the basis of these claims divisional applications.

Reference list

1 torque transmitting device 25 retaining ring

2 drive shaft 26 support surface

3 insertion opening 27 back

4 torsion zone / energy storage 28 polygonal section

5 Power unit 29 Cavity

6 Drive motor 30 Labeling sleeve

7 rotary blower

8 chucks

9 screwdriver bit

10 inner sleeve

11 outer sleeve

12 opening edge

13 ring magnet

13 'face

13 "front edge

14 hexagonal section

15 working peak

16 rear stop

17 backward counter-attack

18 hexagonal section

19 Six internal profile

20 screw

21 screw head

22 screwing entry opening

23 injection opening

24 second torsion zone

Claims

1. torque transmission device (1) with a in a chuck (8) of a rotary drive device insertable drive shaft (2), the inner sleeve (10) inserted in an inner, which has an insertion opening (3) for receiving a

Screwdriver bit (9), which is formed so that the profiled working tip (15) of the insertion opening (3) in the screwdriver bit (9) protrudes beyond the edge (12) of the insertion opening (3), and with an outer sleeve (11) , the stop limited on the inner sleeve (10) between a first stop position, in which a rear stop (16) of the outer sleeve (11) against a rear counter-stop (17) of the inner sleeve (10) and a fixed to the outer sleeve (11) connected Ring magnet (13) at a distance from the edge (12) of the insertion opening (3), and a second stop position, in which the ring magnet (13) on the edge (12) of the insertion (3), is displaced back and forth, characterized characterized in that the outer sleeve (11) is held by a magnetic attraction of the ring magnet (13) in the second stop position, which force of attraction for displacing the outer sleeve (11) in the direction of the ers te stop position by applying a tensile force on the outer sleeve (11) must be overcome.

2. A torque transmission device according to claim 1 or in particular according thereto, characterized by a between the clamping end of the drive shaft (2) and the insertion opening (3) arranged by

Applying a torque twisting torsion section (4) forming an energy storage.

3. torque transmission device according to one or more of the preceding claims or in particular according thereto, characterized records that the magnetic attraction force is so great that ring magnet (13) as a result of the vibration generated by the rotational shock only far enough from the insertion opening (3) that the magnetic force moves him back to the stop position.

Torque transmission device according to one or more of the preceding claims or in particular according thereto, characterized in that the energy store (4) is dimensioned such that the energy pulses introduced in the form of rotational strokes via the drive shaft (2) into the energy store (4) are time-stretched or are attenuated that held by screws by magnetic attraction on the front side of a screw head (21) ring magnet (13) as a result of the vibrations generated by the rotational shock only far enough from the front side of the screw head (21) can remove that the magnetic force again moved back into the contact position to the front side of the screw head (21).

Torque transmission device according to one or more of the preceding claims or in particular according thereto, characterized in that the first stop (16) of an inner annular step of the outer sleeve (11) is formed and the counter-stop of a corresponding annular step (17) of the inner sleeve (10) is formed ,

6. torque transmission device according to one or more of the preceding claims or in particular according thereto, characterized in that the ring magnet (13) positive, non-positive or materially inserted in an opening of the outer sleeve (11) and in particular in a press-in opening (23) is pressed.

Torque transmission device according to one or more of the preceding claims or in particular according thereto, characterized in that the torsion zone (4) between a in the inner sleeve (10) pressed polygonal section (28) of the drive shaft (2) and the clamping end of the drive shaft (2) is arranged wherein the torsion zone (4) is disposed within the inner sleeve (10).

Torque transmission device according to one or more of the appended claims or in particular according thereto, characterized by a second, outside the inner sleeve (10) lying torsion zone (24).

Torque transmission device according to one or more of the preceding claims or in particular according thereto, characterized in that the inner sleeve (10) consists of a ferromagnetic material.

10. torque transmission device according to one or more of the preceding claims or in particular according thereto, characterized in that the axial length of the torsion zone (4) between 10mm and

15mm and the diameter of the torsion zone (4) is less than 6mm, the material hardness of the torsion zone (4) is between 44 HRC and 62 HRC.

11. A torque transmission device according to one or more of the preceding claims or in particular according thereto, characterized by a stop portion (18) which strikes against a counter-stop (19) of the inner sleeve (10) at a maximum angle of rotation of the torsion zone, wherein the stopper portion (16) in particular more - is edged and with a rotary motion game a polygonal opening (19) of the sleeve (10) passes through.

Torque transmission device according to one or more of the preceding claims or in particular according thereto, characterized in that the outer sleeve forms a splinter protection sleeve.

Use of a torque transmission device according to one or more of claims 2 to 8 together with a rotary impact wrench (5) which has a rotary blower generator (7) which can be driven in rotation by a motor (6) and which is mounted on a chuck (8) coupled to the drive shaft (2) ) transmits at least 1000 hurdles per minute, preferably each hitting a peak torque of at least 75 Nm, and with a screwdriver bit (9).