WO2013078381A1

WO2013078381A1 - Chuck with jam release

Info

Publication number: WO2013078381A1
Application number: PCT/US2012/066352
Authority: WO
Inventors: Daniel F. HECK; Qiang J. Zhang
Original assignee: Black & Decker Inc.
Priority date: 2011-11-22
Filing date: 2012-11-21
Publication date: 2013-05-30

Abstract

A chuck that includes a body, a plurality of jaws, a threaded element, a plurality of bearing elements, and a release mechanism. The threaded element is threadably coupled to one of the body and the plurality of jaws. The bearing elements are in a load path between the jaws and the body and are configured to transmit a load to the body when the jaws are tightened about a tool bit. The release mechanism is configured to selectively move a portion of a bearing race into which the bearing elements are received to reduce the load that is transmitted through the bearing elements to the body.

Description

CHUCK WITH JAM RELEASE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 61/562,723, filed on November 22, 201 1 . The entire disclosure of the above application is incorporated herein by reference.

FIELD

[0002] The present disclosure relates to a chuck with a jam release.

BACKGROUND

[0003] This section provides background information related to the present disclosure which is not necessarily prior art.

[0004] A power tool, such as a hand-held drill or a drill press, generally includes a chuck coupled to an output spindle. The chuck is configured to hold a tool bit, such as a drill bit or a screwdriving bit. The chuck, which can be any type of chuck, such as a pusher chuck, can be difficult to loosen under some circumstances.

[0005] Pusher chucks, also known as self-centering chucks, are a type of self-tightening chuck that is known in the art. Such chucks automatically tighten their grip on a tool bit as the power tool drives the chuck in a predetermined direction. With reference to Figure 26, a conventional pusher chuck typically includes cylindrical body 2000 that is configured to be fixedly connected to a spindle (not shown). The body 2000 includes a threaded opening 2002 into which a self-tightening screw 2004 is threaded. The self-tightening screw 2004 has a plurality of slots 2006 into which are received corresponding jaws 2008 (only one is shown in the drawing). The jaws 2008 are also disposed in longitudinal slots 2010 in a jaw carrier 2012, which also partially surrounds the body 2000. One or more bearing elements, such as bearing balls 2014, can be received between the jaw carrier 2012 and the body 2000. A nosecone 2016, which is mounted about jaw carrier 2012, can be employed to shroud a front side of the jaws 2008 and the jaw carrier 2012. A rotatable outer sleeve 2018 can be coupled to the jaw carrier 2012 and/or the nosecone 2016 for common rotation. A ratchet pawl 2020 can couple the outer sleeve 201 8 to the body 2000. A manual rotary input to the outer sleeve 2018 will cause corresponding rotation of the nosecone 2016, which drives the self-tightening screw 2004 through the jaws 2012. A rear dust cap 2022 fits over the rear of the outer sleeve 2018. An example of this type of self-tightening chuck is manufactured and marketed by ROHM GmbH of Baden-Wurttemberg, Germany as their model number 330075- 90 chuck. Another example of this type of self-tightening chuck can be found in U.S. Pat. App. Pub. No. 201 1 /0024997, filed July 27, 2010, titled "Self-Tightening Chuck with a Radial Lock," which is incorporated by reference.

[0006] In operation, a user of the power tool can insert a tool bit between the jaws and can rotate the outer sleeve in the tightening direction, which causes the nosecone 2016, the jaw carrier 2012, the jaws 2008, and the self-tightening screw 2004 to rotate in the same direction, while the body 2000 remains stationary. As the power tool typically includes a spindle lock (not shown) that prevents the body 2000 from back-driving the output spindle of the power tool, the body 2000 remains stationary as the self-tightening screw 2004 rotates, causing the self-tightening screw 2004 to drive the jaws 2008 axially away from the body 2000. It will be appreciated that contact between the nosecone 2016 and the jaws 2008 drives the jaws 2008 radially inwardly toward one another so that the jaws 2008 close against and contact the tool bit. The user can continue to rotate the outer sleeve 2018 a little bit further at this point, which causes the ratchet 2020 to lock the jaw carrier 2012 to the body 2000 so that the jaw carrier 2012 will co-rotate with the body 2000.

[0007] Due to the torque reaction on the tool bit when the user operates the power tool in the predetermined rotational direction, the self-tightening screw 2004 will automatically continue to rotate in the tightening direction relative to the body 2000, which pushes the jaws 2008 further inwardly toward one another to clamp even more tightly on the tool bit.

[0008] When the user is finished using the power tool, the grip or clamping force applied by the jaws 2008 to the tool bit can be removed by rotating the outer sleeve 2018 in a loosening direction, which first unlocks the pawl 2020 from the body 2000 and then rotates the nosecone 2016, the jaws 2008, the jaw carrier 2012 and the self-tightening screw 2004 relative to the body 2000 so that the jaws 2008 retract from the tool bit. It is possible for the jaws 2008 to become so tightly clamped against the tool bit that the jaw carrier 2012 becomes jammed against the body 2000 (hereinafter referred to as a "jam condition"). In such situations, it can be very difficult for the user to loosen the grip of the jaws 2008 without using a tool, such as a pipe wrench, to rotate the outer sleeve 2018. We believe that it would be desirable to have a self-tightening chuck with a mechanism that permits a user to clear a jam condition without the use of a tool.

SUMMARY

[0009] This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

[0010] In one form, the present teachings provide a chuck having a body that is connectable to a spindle of a power tool. A jaw carrier is rotationally received over a portion of the body. The jaw carrier defines a plurality of slots, each of which receives a jaw that is moveable both axially and radially relative to the jaw carrier. At least one bearing element is disposed between the jaw carrier and the body to facilitate rotation of the jaw carrier relative to the body. A pawl is coupled to one of the jaw carrier and the body. An outer sleeve can be rotated to selectively lock the pawl to the other of the jaw carrier and the body. The body includes a threaded axial bore, and a self-tightening screw is threaded into the axial bore. The screw is also coupled to the jaws so that rotation of the screw causes axial and radial movement of the jaws. When the pawl is locked, operation of the power tool causes the screw thread to automatically tighten the grip of the jaws on a bit. The chuck further includes a quick-release mechanism that can be selectively actuated to release tension between the at least one of the body, the jaw carrier and the bearing when these components become jammed due to over-tightening of the jaws on the bit. The quick release mechanism includes any mechanism that provides a clearance between components of the chuck (e.g., between the bearing and the body and/or between the bearing and the jaw carrier) to reduce the tension in the chuck that is created when it self-tightens.

[0011] In another form, the present teachings provide a chuck having a body that is connectable to a spindle of a power tool. A jaw carrier is rotationally received over a portion of the body. The jaw carrier defines a plurality of slots, each of which receives a jaw that is moveable both axially and radially relative to the jaw carrier. At least one bearing element is disposed between the jaw carrier and the body to facilitate rotation of the jaw carrier relative to the body. A pawl is coupled to one of the jaw carrier and the body. An outer sleeve can be rotated to selectively lock the pawl to the other of the jaw carrier and the body. The body includes a threaded axial bore, and a self-tightening screw is threaded into the axial bore. The screw is also coupled to the jaws so that rotation of the screw causes axial and radial movement of the jaws. When the pawl is locked, operation of the power tool causes the screw thread to automatically tighten the grip of the jaws on a bit. The chuck further includes a quick-release mechanism that can be selectively actuated by rotating the outer sleeve when the chuck becomes jammed due to over-tightening of the jaws on the bit.

[0012] In still another form, the present teachings provide a chuck that includes a body, a jaw carrier, a plurality of bearing elements, a self-tightening screw, a plurality of jaws and a release mechanism that is configured for clearing a jam condition that locks the self-tightening screw, the jaw carrier and the body together. The jaw carrier has a plurality of longitudinal jaw slots. The bearing elements are disposed between the jaw carrier and the body and support the jaw carrier for rotation on the body. The self-tightening screw has a threaded portion, which is threadably engaged to the body, and a head having a plurality of radial jaw slots. Each of the jaws is received in a corresponding one of the radial jaw slots and a corresponding one of the longitudinal jaw slots. The release mechanism is configured to move at least a portion of the jaw carrier relative to the bearing elements such that load transmitted from the jaw carrier through the bearing elements to the body is reduced or eliminated.

[0013] In yet another form, the present teachings provide a chuck that includes a body, a plurality of jaws, a threaded element, a plurality of bearing elements, and a release mechanism. The threaded element is threadably coupled to one of the body and the plurality of jaws. The bearing elements are in a load path between the jaws and the body and are configured to transmit a load to the body when the jaws are tightened about a tool bit. The release mechanism is configured to selectively move a portion of a bearing race into which the bearing elements are received to reduce the load that is transmitted through the bearing elements to the body.

[0014] Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

[0015] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0016] Figure 1 is a side elevation view of an exemplary power tool having a chuck constructed in accordance with the teachings of the present disclosure;

[0017] Figure 2 is a longitudinal section view of the chuck of Figure 1 illustrating the chuck in a jam condition;

[0018] Figure 3 is a view similar to that of Figure 2, but depicting operation of a release mechanism to remove the jam condition;

[0019] Figures 4 and 5 are similar to Figures 2 and 3, respectively, but depicting an alternately constructed chuck;

[0020] Figure 6 is a longitudinal section view of yet another chuck constructed in accordance with the teachings of the present disclosure;

[0021] Figure 7 is a fragmentary perspective view of a portion of the chuck of Figure 6;

[0022] Figure 8 is a side elevation view of a portion of the chuck of Figure 6;

[0023] Figure 9 is an enlarged portion of Figure 6, illustrating a portion of a release mechanism in more detail; [0024] Figure 10 is a view similar to that of Figure 8 but depicting interaction between portions of the release mechanism when the chuck is tightened;

[0025] Figure 1 1 is longitudinal section view of a portion of the chuck taken when the chuck is in the condition illustrated in Figure 10;

[0026] Figure 12 is a view similar to that of Figure 8 but depicting operation of the release mechanism;

[0027] Figure 13 is a longitudinal section view of a portion of the chuck taken when the chuck is in the condition illustrated in Figure 12;

[0028] Figure 14 is an exploded perspective view of still another chuck constructed in accordance with the teachings of the present disclosure;

[0029] Figure 15 is a longitudinal section view of the chuck of Figure 14;

[0030] Figure 16 is a lateral section view of a portion of the chuck of

Figure 14 illustrating a portion of a jaw carrier, a portion of an outer sleeve and a return spring in more detail;

[0031] Figure 17 is a front perspective view of a portion of the chuck of

Figure 14 illustrating the outer sleeve in more detail;

[0032] Figure 18 is a lateral section view taken through the chuck of Figure 14 illustrating a locking mechanism when the outer sleeve is positioned in Position 1 ;

[0033] Figure 19 is a lateral section view taken through the chuck of Figure 14 illustrating a portion of a release mechanism when the outer sleeve is positioned in Position 1 ;

[0034] Figure 20 is a view similar to that of Figure 18 but depicting the outer sleeve in Position 2;

[0035] Figure 21 is a view similar to that of Figure 19 but depicting the outer sleeve in Position 2;

[0036] Figure 22 is a view similar to that of Figure 16, but illustrating the outer sleeve in Position 2 relative to the jaw carrier;

[0037] Figure 23 is a view similar to that of Figure 18 but depicting the outer sleeve in Position 3; [0038] Figure 24 is a view similar to that of Figure 19 but depicting the outer sleeve in Position 3;

[0039] Figure 25 is a longitudinal section view of another chuck constructed in accordance with the teachings of the present disclosure, the chuck being a ratchet chuck; and

[0040] Figure 26 is a longitudinal section view of a portion of a prior art self-tightening chuck (pusher chuck).

[0041] Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

[0042] With reference to Figure 1 , a power tool 10 is illustrated in operative association with a self-tightening chuck 12 that is constructed in accordance with the teachings of the present disclosure. The power tool 10, which is a hand-held tool that is configured to provide a rotary output, can otherwise be conventionally constructed. In the particular example provided, the power tool 10 is a hammer-drill/driver, but it will be appreciated that the teachings of the present disclosure have application to various other types of power tools, including without limitation drills, drill/drivers, rotary hammers, screwdrivers and impact wrenches. The power tool 10 can have a housing 14 with a handle 16. The power tool 10 is coupleable to a power source, such as a battery 18 that is coupleable to the distal end of the handle 16. Disposed in the housing 14 is an electric motor 20 (e.g., an AC, DC, brushless, or universal motor), which is connected to a transmission 22 (e.g., a planetary gear transmission), which in turn is connected to an output spindle 24. A variable speed trigger switch 26 is configured to permit selective control of energy transmitted from the power source 18 to the motor 20. The output spindle 24 can be coupled to the chuck 12 in a conventional manner (e.g., the chuck can be threaded onto the distal end of the output spindle 24). It should be understood that while the chuck 12 has been depicted as being associated with a hand-held power tool, it will be appreciated that the chuck 12 could be associated with a stationary power tool (e.g., a drill press, a laythe). Moreover, it will be appreciated that the chuck 12 need not be mounted on a powered spindle (it could be mounted, for example on a non-rotating spindle of a tailstock of a laythe).

[0043] With reference to Figure 2, the chuck 12 can include a body 102, a self-tightening screw 104, a plurality of jaws 108, a jaw carrier 1 12, one or more bearing elements (e.g., bearing balls 1 14), a nosecone 1 16, an outer sleeve 1 18, a locking mechanism 120, a rear dust cap 122 and a release mechanism 124. The body 102 can define a threaded opening 102 into which the self-tightening screw 104 can be threadably received. The body 102 can be configured to be coupled to the output spindle 24 (Fig. 1 ) in any desired manner, such as via a plurality of mounting threads 150. The self-tightening screw 104 can have a threaded body 152, and a head 154 into which a plurality of radially extending T- shaped, radially extending slots 106 can be formed. Each of the jaws 108 can have a T-shaped portion 156, which can be matingly received in a corresponding one of the slots 106, and an outer frusto-conical edge 158 that can taper radially inwardly toward the rotational axis 160 of the chuck 12 with increasing distance from the T-shaped portion 156. The bearing balls 1 14 can be received between the body 100 and the jaw carrier 1 12 such that the jaw carrier is rotatable about the body 100. The jaw carrier 1 12 can include a first carrier portion 164, a second carrier portion 166 and a third carrier portion 168. The first carrier portion 164 can define a plurality of longitudinal slots 1 10, which are configured to each receive a respective one of the jaws 108, and a hollow cylindrical portion 170 that can be rotatably disposed about a forward end of the body 100. The second carrier portion 166 can be hollow and can be received about the body 100 axially rearward of the hollow cylindrical portion 170. The first and second carrier portions 164 and 166 can cooperate to define an outer bearing race 174 into which the bearing element(s) 1 14 can be received. As assembled in this manner, the first and second carrier portions 164 and 166 can be axially spaced apart from one another. The third carrier portion 168 can be a hollow structure that can be received about the hollow cylindrical portion 170 and the second carrier portion 166. The third carrier portion 168 can be fixedly coupled to the nosecone 1 16 in any desired manner, such as via a set of mating threads. The nosecone 1 16 can be mounted about jaw carrier 1 12, can be employed to shroud a front side of the jaws 108 and the jaw carrier 1 12. The locking mechanism 120 can comprise any mechanism for selectively locking the outer sleeve 1 18 to the body 100. In the particular example provided, the locking mechanism 120 includes a pawl 120a that is pivotally mounted on a pin 120b that is fixed to the second carrier portion 166. The rear dust cap 122 fits over the rear of the outer sleeve 1 18.

[0044] The release mechanism 124 can be configured to selectively reduce tension in the self-tightening screw 104 without rotating the self- tightening screw relative to the body 100. The release mechanism 124 can include at least one locking element, such as at least one locking ball 180, a locking sleeve 182, a first return spring 184, a push disk 186, and a second return spring 188. The locking ball(s) 180 can be received in radially extending apertures 190 formed in the second carrier portion 166 of the jaw carrier 1 12. The radially extending apertures 190 can be configured such that movement of the locking ball(s) 180 into the radially extending apertures 190 in a radially inward direction causes axial forward movement of the second carrier portion 166 such that the portion of the bearing race 174 defined by the second carrier portion 166 is abutted against the bearing balls 1 14 and drives the bearing balls 1 14 radially inwardly against the body 100. The locking sleeve 182 can be received concentrically about the second carrier portion 166 and can define an engagement structure 194 and one or more unlocking recesses 196. The first return spring 184 can be configured to bias the locking sleeve 182 relative to the second carrier portion 166 in an axial direction such that the engagement structure 194 is disposed in contact with the locking ball(s) 180. In the particular example provided, the first return spring 184 is a helical compression spring that is disposed axially between the locking sleeve 182 and the nosecone 1 16. The push disk 186 can be axially slidably mounted on the body 100 at a location that is axially rearward of the rear dust cap 122. The second return spring 188 can be any type of spring, such as a leaf spring, that is configured to bias the push disk 186 in an axially rearward direction away from the rear dust cap 122. One or more pins 198 can connect the push disk 186 to the locking sleeve 182 so that movement of the push disk 186 in an axially forward direction causes corresponding forward motion of the locking sleeve 182.

[0045] It will be appreciated that the chuck 12 can be tightened about a tool bit (not shown) in a manner that is similar to that which was described for the chuck of Figure 26. In certain situations, the chuck 12 can self-tighten to a jam condition (shown in Figure 2) where it would be difficult for a user to exert sufficient torque on the outer sleeve 1 18 to cause the jaws 108 to retract from the tool bit solely though hand-rotation of the outer sleeve 1 18. In this condition, the head 154 of the self-tightening screw 104 is not abutted against the axial end of the body 100, but rather threaded engagement of the threaded body 152 to the mating threads of the body 100 can draw the self-tightening screw 104 axially rearward relative to the body 100 while the jaws 108 are gripping against the tool bit. The further tightening of the self-tightening screw 104 generates a clamping force that is transmitted through the jaw carrier 1 12 and applied (through the portion of the bearing race 174 associated with the second carrier portion 166) through the bearing balls 1 14 and to the body 100. In a jam condition, the clamping forces that are transmitted from the jaw carrier 1 12 through the bearing balls 1 14 and into the body 100 are sufficiently high that it is difficult to loosen the chuck 12 through manual rotation of the outer sleeve 1 18.

[0046] With reference to Figure 3, the release mechanism 1 24 may be operated by a user to release the jam condition. In this regard, an axially forward directed force can be applied to the push disk 186 to cause corresponding forward movement of the locking sleeve 182 in the direction of arrow A such that the unlocking recess(es) 196 are disposed radially outwardly of the locking ball(s) 180. Movement of the locking ball(s) 180 into the unlocking recess(es) 196 eliminates or substantially reduces the radially inwardly directed clamping force that had been possible through contact between the engagement structure 194, the locking ball(s) 180 and the second carrier portion 166. In this regard, radial outward movement of the locking ball(s) 180 in the direction of arrow B into the unlocking recess(es) 196 permits the second carrier portion 166 to move rearwardly in the direction of arrow C, providing a clearance between the bearing balls 1 14 and the first carrier portion 164 of the jaw carrier 1 12 to thereby release the clamping force on the bearing balls 1 14. This releases some or all of the tension in the chuck 12 and permits a user to easily rotate the outer sleeve 1 18 in the unlocking direction to open the jaws 108. Once the jaws 108 have been sufficiently opened, the first and second return springs 184 and 188 can move the locking sleeve 182 and the push disk 186 in an axially rearward direction. Such movement of the locking sleeve 182 causes the engagement structure 194 to move the locking ball(s) 180 radially inwardly into the unlocking recess(es) 196 to non-rotatably couple the locking sleeve 182 to the second carrier portion 166. Movement of the push disk 186 in the axially rearward direction permits corresponding rearward movement of the pins 198, which provides space for the rearward movement of the locking sleeve 182 that is caused by the first return spring 184.

[0047] While the chuck 12 has been described as having a release mechanism 124 with a push disk 186 that is movable relative to the outer sleeve 1 18 of the chuck 12, it will be appreciated that the push disk 186 could be integrated into the outer sleeve 1 18 so that the outer sleeve 1 18 moves with the push disk 186. Also alternatively, the push disk 186 could be omitted altogether and the outer sleeve 1 18 could be configured to receive an axially directed force for moving the locking sleeve 182.

[0048] With reference to Figures 4 and 5, an alternately constructed chuck 12' is illustrated. The chuck 12' is generally similar to the chuck 12 of Figure 2, except for the configuration of the portions of the body 100' and the bearing race 174' (defined by the first and second carrier portions 164' and 166') that are contacted by the bearing balls 1 14 and for the configuration of the portion of the locking sleeve 182' that is contacted by the locking ball(s) 180. Regarding the former change in configuration, the portions of the body 100' and the jaw carrier 1 12' that are contacted by the bearing balls 1 14 are provided with additional clearance that permits an increased level of de-tensioning of the chuck 12' when the release mechanism 124' is operated. Regarding the latter change in configuration, the configuration of the engagement structure 194' and the transition to the unlocking recess(es) 196' has been changed to reduce the force needed to move the push disk 186 in the forward and rearward directions during operation of the release mechanism 124'. In this regard, some or all of the interior surface S of the locking sleeve 182' that contacts the locking ball(s) 180' can be shaped in a frusto-conical manner that converges toward the rotational axis 160 with decreasing distance to the jaws 108.

[0049] With reference to Figure 6, a second self-tightening chuck constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral 212. The chuck 212 can include a body 300, a self-tightening screw 302, a plurality of jaws 308, a jaw carrier 312, one or more bearing elements (e.g., bearing balls 314), a nosecone 316, an outer sleeve 318, a locking mechanism 320, a rear dust cap 322 and a release mechanism 324. The body 300, the self-tightening screw 302, the jaws 308, the jaw carrier 312, the bearing balls 314, the nosecone 316, the locking mechanism 320 and the rear dust cap 322 can be generally similar to the corresponding components discussed above and as such, these components will not be described in significant detail herein.

[0050] The release mechanism 324 can be generally similar to the release mechanism 124 of Figure 2, except that it is configured to be operated with a torsional input applied to a drive sleeve, rather than an axial force directed to a push disk. The release mechanism 324 can include at least one locking element, such as at least one locking ball 380, a locking sleeve 382, a first return spring 384, a drive sleeve 386 and a second return spring 388. The locking ball(s) 380 can be received in radially extending apertures 390 formed in the second carrier portion 366 of the jaw carrier 312. The radially extending apertures 390 can be configured such that movement of the locking ball(s) 380 into the radially extending apertures 390 in a radially inward direction causes axial forward movement of the second carrier portion 366 such that the portion of the bearing race 374 defined by the second carrier portion 366 is abutted against the bearing balls 314 and drives the bearing balls 314 radially inwardly against the body 300. The locking sleeve 382 can be received concentrically about the second carrier portion 366 and can define an engagement structure 394 and one or more unlocking recesses 396. The first return spring 384 can be configured to bias the locking sleeve 382 relative to the second carrier portion 366 in an axial direction such that the engagement structure 394 is disposed in contact with the locking ball(s) 380. In the particular example provided, the first return spring 384 is a helical compression spring that is disposed axially between the locking sleeve 382 and the nosecone 316. The drive sleeve 386 can be coupled to the outer sleeve 318 via a key 400 (Fig. 7). The first return spring 384 can be disposed between the locking sleeve 382 and the nosecone 316 and can effectively bias the locking sleeve 382 toward the drive sleeve 386. The second return spring (not shown) can be disposed between the drive sleeve 386 and the rear dust cap 322.

[0051] With reference to Figures 6 and 8, the locking sleeve 382 can be coupled to the third carrier portion 368 of the jaw carrier 312 by a stop pin 404 on the third carrier portion 368 that rides in a slot 406 in the locking sleeve 382. The slot 406 can define a ramp surface 408 on which the stop pin 404 slides. The locking sleeve 382 can have a plurality of ratchet teeth 410 that can be configured to engage corresponding ratchet teeth 412 on the drive sleeve 386. The ratchet teeth 410, 412 extend in a circumferential direction, tapering in an axial direction from a root to a crest. The ratchet teeth 410, 412 are arranged to permit rotation of the ratchet teeth 410 in a predetermined rotational direction relative to the ratchet teeth 412, but not in an opposite rotational direction.

[0052] With reference to Figures 6, 8 and 9, a tool bit (not shown) can be inserted into the chuck 212 and the outer sleeve 318 can be rotated in the tightening direction to engage the jaws 308 to the tool bit. In this condition, the locking sleeve 382 is disposed axially such that the engagement structure 394 is disposed radially in-line with the locking ball(s) 380, forcing the locking ball(s) 380 radially inwardly into the radially extending aperture(s) 390 in the second carrier portion 366, thereby urging the second carrier portion 366 forwardly so that the portion of the bearing race 374 defined by the second carrier portion 366 is abutted against the bearing balls 314.

[0053] With reference to Figures 6, 10 and 1 1 , the outer sleeve 318 can be rotated in the tightening direction (in the direction of arrow D) to cause the locking mechanism 320 to lock the jaw carrier 312 to the body 300, which permits the chuck 312 to self-tighten during operation. This movement of the outer sleeve 318 also causes rotation of the drive sleeve 386 relative to the locking sleeve 382 during which the ratchet teeth 412 of the drive sleeve 386 ride over (cam over) the ratchet teeth 410 of the locking sleeve 382 and cause the drive sleeve 386 to travel axially rearward in the direction of arrow E. It will be appreciated that earning of the ratchet teeth 412 over the ratchet teeth 410 provides feedback to the user of the chuck 312 that the jaws 308 have been sufficiently tightened against the tool bit to permit the chuck 312 to operate in a self-tightening mode. It will further be appreciated that after the ratchet teeth 412 have cammed over the ratchet teeth 410, the ratchet teeth 410, 412 can be arranged relative to one another as is shown in Figure 8.

[0054] With reference to Figures 12 and 13, the chuck 312 may be in a jam condition after use. To release the jam condition, the drive sleeve 386 can be rotated in the rotational direction of arrow F through corresponding rotation of the outer sleeve 318. Due to engagement of the ratchet teeth 410, 412, rotation of the drive sleeve 386 in the direction of arrow F causes corresponding rotation of the locking sleeve 382. Since the pin 404 on the second carrier portion 366 is received in the slot 406 in the locking sleeve 382 and rides against the tapered surface 408, rotation of the locking sleeve 382 relative to the second carrier portion 366 in the rotational direction of arrow F causes the locking sleeve 382 to move axially forward in the direction of arrow A. The slot 406 extends in a circumferential direction by a distance that is sufficient to permit the ratchet teeth 410 to disengage the ratchet teeth 412 so that the ratchet teeth 412 can cam or ride over the ratchet teeth 410 by a single tooth. The forward movement of the locking sleeve 382 orients the unlocking recess(es) 396 radially in-line with the locking ball(s) 180 to permit the release of the jam condition in a manner similar to that which was described in conjunction with the example of Figure 2. When the ratchet teeth 412 have cammed or ridden over the ratchet teeth 410 by a single tooth, the first return spring 384 can shift the locking sleeve 382 axially rearward, while the second return spring can rotate the locking sleeve 382 in a rotational direction opposite to the rotational direction of arrow F, thereby resetting the chuck 312. [0055] With reference to Figures 14 and 15, another chuck constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral 412. The chuck 812 can be generally similar to the chuck 12 of Figure 2 and can include a body 500, a self-tightening screw 504, a plurality of jaws 508, a jaw carrier 512, one or more bearing elements (e.g., bearing balls 514), a nosecone 516, an outer sleeve 518, a locking mechanism 520 and a release mechanism 524. The body 500, the self-tightening screw 504, the jaws 508, and the bearing balls 514 are generally similar to corresponding elements in the above examples and as such, a detailed discussion of these components need not be provided herein.

[0056] The jaw carrier 512 can comprise a first carrier portion 564, a second carrier portion 566, and third carrier portion 568. The first carrier portion 564 can define a plurality of longitudinal slots 51 0, which are configured to each receive a respective one of the jaws 508, and a hollow cylindrical portion that can be received over a forward end of the body 500. The second carrier portion 566 can be an annular structure that can be received about the body 500. The second carrier portion 566 can have a tapered rearward surface 600 that can be frusto-conically shaped to diverge outwardly with decreasing distance toward the first carrier portion 564. The first and second carrier portions 564 and 566 can define a bearing race 574 into which the bearing balls 514 can be received. The third carrier portion 568 can be a hollow cylindrical structure that can be disposed about the body 500 and the first and second carrier portions 564 and 566 and threadably coupled to the nosecone 516. The third carrier portion 568 can define a plurality of detent pockets 604, which can be circumferentially spaced apart on an axial rear surface of the third carrier portion 568, a pin pocket 608 (Fig. 16) and a spring pocket 610. The pin pocket 608 and the spring pocket 610 can be grooves that can extend in a circumferential direction on the outside diametrical surface of the third carrier portion 568. In the example provided, one end of the pin pocket 608 intersects the spring pocket 610 and the spring pocket 610 is configured to receive the return spring 584. The outer sleeve 518 can be rotatably mounted on the body 500 and can shroud an outer side of the third carrier portion 568 and the nosecone 516. [0057] With reference to Figures 16 and 17, the outer sleeve 518 can have an annular side wall 620 and a rear wall 622 that can be coupled to a rear end of the annular side wall 620. A stop pin 624 can be received through the annular side wall 620 and can be received into the pin pocket 608 in the third carrier portion 568. The return spring 584, which can be received in the spring pocket 610 and can apply a force to the stop pin 624 that biases the outer sleeve 518 in a predetermined rotational direction relative to the third carrier portion 568. Contact between the stop pin 624 and a first side 628 of the pin pocket 608 can inhibit relative rotational movement between the outer sleeve 518 and the third carrier portion 568 when the outer sleeve 518 is rotated in a first rotational direction (i.e., the tightening direction). The return spring 584 permits limited relative rotational movement between the outer sleeve 518 and the third carrier portion 568 in an opposite rotational direction and biases the stop pin 624 to a predetermined position (i.e., Position 1 ) relative to the third carrier portion 568. A plurality of detent recesses can be formed in the rear wall 622. The detent recesses can include a first detent recess 630, a second detent recess 632 and a detent groove 634 that can intersect and extend in a circumferential direction from the second detent recess 632 in a direction away from the first detent recess 630. Stated another way, the second detent recess 632 is disposed between the first detent recess 630 and the detent groove 634. With additional reference to Figure 14, a plurality of detents 640 can be mounted to the third carrier portion 568. Each of the detents 640 can comprise a helical compression spring 642 and a detent member 644. The helical compression spring 642 can be received into a corresponding one of the detent pockets 604 formed in the third carrier portion 568 and can bias an associated one of the detent members 644 in an axial rearward direction toward the rear wall 622 of the outer sleeve 518. Each detent member 644 can be configured to be received in the detent recesses. Engagement of the detent members 644 to the first detent recesses 630 resists (but does not inhibit) rotation of the outer sleeve 518 relative to the third carrier portion 568. Engagement of the detent members 644 to the second detent recesses 632 resists rotation of the outer sleeve 518 in a rotational direction toward the first detent recesses 630 but does not inhibit rotation of the outer sleeve 518 in an opposite rotational direction. In this regard, rotation of the outer sleeve 518 in the opposite rotational direction causes the detent members 644 to travel in an associated one of the detent grooves 634.

[0058] In Figures 14, 15 and 17, the release mechanism 524 can comprise a plurality of wedge pockets 650, a plurality of wedges 652, a plurality of rollers 654, and a cam track 656. The wedge pockets 650 can be formed radially through the third carrier portion 568 and can be spaced circumferentially apart about the circumference of the third carrier portion 568. Each wedge pocket 650 can have a tapered forward surface 660. The wedges 652 can have tapered axial end faces 662 and 664 and a roller contact surface 668. The tapered axial end faces 662 and 664 can be configured to slidably engage the tapered rearward surface 600 and the tapered forward surface 660, respectively, formed on the second and third carrier portions 566 and 568, respectively. The tapered axial end faces 662 and 664, the tapered rearward surface 600 and the tapered forward surface 660 can be sloped so that radially inward movement of the wedges 652 tends to force the tapered rearward surface 600 apart from the tapered forward surface 660. The roller contact surface 668 is configured to receive a corresponding one of the cylindrically shaped rollers 654. The cam track 656 can be fixedly coupled to the outer sleeve 518 and can include an engagement portion 670 and a disengagement portion 672. The cam track 656 is engaged by the rollers 654 so that rotation of the outer sleeve 518 relative to the third carrier portion 568 can control positioning of the rollers 654 on either the engagement portion 670 or the disengagement portion 672. Positioning of the rollers 654 on the engagement portion 670 urges the wedges 652 radially inwardly such that the tapered axial end faces 662 and 664 engage the tapered rearward surface 600 and the tapered forward surface 660 to drive the tapered rearward surface 600 and the tapered forward surface 660 axially apart from one another. Positioning of the rollers 654 on the disengagement portion 672 permits the wedges 652 to move radially outwardly so that the tapered rearward surface 600 can move in an axially rearward direction relative to the tapered forward surface 660. [0059] With reference to Figures 15, 16, 18 and 19, the outer sleeve 518 can be rotated in the tightening direction to tighten a tool bit (not shown) in the chuck 812. The locking mechanism 520 can be engaged (in the example shown, the locking mechanism 520 includes a pawl 680 that is pivotably mounted about a pivot pin 682 that is fixed to the third carrier portion 568; a pawl spring 684 can bias the pawl 680 about the pivot pin 682 such that a pawl member 688 on the pawl 680 engages one or more teeth 690 formed on the body 500; a pawl control groove 694 is formed in the outer sleeve 518 and configured to coordinate pivotal movement of the pawl 680 about the pivot pin 682 in a desired manner) to lock the third carrier portion 568 to the body 500. The outer sleeve 518 can be positioned relative to the third carrier portion 568 such that the rollers 654 are positioned on the engagement portion 670 of the cam track 656 to thereby force the wedges 652 in a radially inward direction to force the tapered rearward surface 600 axially apart from the tapered forward surface 660, thereby urging the second carrier portion 566 forwardly such that the portion of the bearing race 574 defined by the second carrier portion 566 against the bearing balls 514. The chuck 812 can be operated in a self- tightening mode in this condition. The detent members 644 can engage the first detent recesses 630.

[0060] With reference to Figures 15, 16, and 20-22, the outer sleeve 518 can be rotated in the direction of arrow 700 into Position 2 to disengage the locking mechanism 520 and retract the jaws 508 from the tool bit. In this position, the stop pin 624 has moved in the pin pocket 608 by a distance that compresses the return spring 584 and the detent members 644 engage the second detent recesses 632.

[0061] With reference to Figures 15, 16, 23 and 24, in the event of a jam condition, the outer sleeve 518 can be further rotated in the direction of arrow 700 relative to the third carrier portion 568 to move the outer sleeve 518 from Position 2 to Position 3. In Position 3, the rollers 654 are positioned on the disengaging portion 672 of the cam track 656 to permit the wedges 652 to move radially outwardly, which permits the second carrier portion 566 to move axially rearward so that the portion of the bearing track 574 that is defined by the second carrier portion 566 can disengage the bearing balls 514. Movement of the outer sleeve 518 into Position 3 causes the detents members 644 to move out of the second detent recesses 632 and into the detent grooves 634. When the operator releases the outer sleeve 518, the return spring 584 biases the outer sleeve 518 in the tightening direction so that the rollers 654 are returned to engagement with the engagement portion 670 of the cam track 656 and the detent members 644 are positioned in the second detent recesses 632.

[0062] While the above-described examples are specific to a pusher- chuck, those of ordinary skill in the art will appreciate that the disclosure has broader implication to various other types of chucks and as such, the teachings of the present disclosure are not limited exclusively to pusher chucks. In this regard, an exemplary ratchet chuck 1012 constructed in accordance with the teachings of the present disclosure is illustrated in Figure 25. Except as otherwise described, the chuck 1012 can be constructed in a manner that is similar to that which is described in U.S. Patent No. 5,816,582, the disclosure of which is incorporated by reference as if set forth in detail in its entirety herein. Briefly, the ratchet chuck 1012 can include a body 1 100, a plurality of jaws 1 108, a bearing 1 1 14, an outer sleeve 1 1 18, a nut 1 130 and a release mechanism 1 124. The body 1 100 defines a plurality of jaw apertures 1 138 into which the jaws 1 108 are slidably received. Each of the jaws 1 108 has a threaded portion 1 140 that can be threadably engaged by the nut 1 130. The outer sleeve 1 1 18 is received over the nut 1 130 and a front end of the body 1 100; the outer sleeve 1 1 18 and the nut 1 130 are coupled to one another for common rotation. The bearing 1 1 14 supports the nut 1 130 for rotation relative to the body 1 100. The release mechanism 1 124, which is schematically illustrated in the figure, can be similar to any of the above-described release mechanisms and is configured to permit selective movement of a portion of a bearing race 1 174 associated with the bearing 1 1 14 to reduce tension in the chuck 1012. In this regard, the release mechanism 1 124 can have a locking sleeve (not specifically shown) that can be moved to cause corresponding movement of the outer bearing race 1 174 in an axially rearward direction to reduce or eliminate tension in the jaws 1 108 that is transmitted through the bearing 1 1 14 to the body 1 1 00. [0063] The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.

Claims

CLAIMS What is claimed is:

1 . A chuck comprising:

a body;

a jaw carrier having a plurality of longitudinal jaw slots;

a plurality of bearing elements between the jaw carrier and the body that support the jaw carrier for rotation on the body;

a self-tightening screw having a threaded portion, which is threadably engaged to the body, and a head having a plurality of radial jaw slots;

a plurality of jaws, each of the jaws being received in a corresponding one of the radial jaw slots and a corresponding one of the longitudinal jaw slots; and a release mechanism for clearing a jam condition that locks the self- tightening screw, the jaw carrier and the body together, the release mechanism being configured to move at least a portion of the jaw carrier relative to the bearing elements such that load transmitted from the jaw carrier through the bearing elements to the body is reduced or eliminated.

2. The chuck of Claim 1 , wherein the jaw carrier comprises a first carrier portion, a second carrier and a third carrier portion, wherein the longitudinal jaw slots are formed in the first carrier portion, wherein the second carrier portion is disposed axially between the first and third carrier portions, and wherein the release mechanism is configured to move the second carrier portion axially away from the first carrier portion when clearing the jam condition.

3. The chuck of Claim 2, wherein the first and second carrier portions cooperate to define an outer bearing race into which the bearing elements are received.

4. The chuck of Claim 3, wherein the release mechanism comprises a locking sleeve and a locking element, wherein the locking sleeve is axially movable between a first position, which drives the locking element into the second carrier portion to cause the second carrier portion to seat against the bearing elements, and a second position which permits the locking element to retract from the second carrier portion to cause the second carrier portion to slide away from the bearing elements.

5. The chuck of Claim 4, wherein the release mechanism comprises a push disk that is axially slidably mounted about the body, the push disk being configured to transmit motion to the locking sleeve to move the locking sleeve from the first position to the second position.

6. The chuck of Claim 4, wherein the release mechanism comprises a drive sleeve that is rotatably mounted about the body, the drive sleeve being configured to transmit motion to the locking sleeve to move the locking sleeve from the first position to the second position.

7. The chuck of Claim 6, wherein the drive sleeve comprises a plurality of first ratchet teeth that are meshingly engaged with second ratchet teeth coupled to the locking sleeve.

8. The chuck of Claim 7, wherein the locking sleeve defines a slot with a tapered surface, wherein a pin is received into the slot and disposed against the tapered surface, and wherein the pin is fixedly coupled to the jaw carrier.

9. The chuck of Claim 3, wherein the release mechanism comprises a plurality of wedges that are radially movable between a first, radially inward position, in which the wedges urge the second carrier portion against the bearing elements, and a second, radially outward position.

10. The chuck of Claim 9, wherein the release mechanism further comprises a cam track and a plurality of rollers that are disposed between the cam track and the rollers, the cam track and the rollers being configured to coordinate movement of the wedges between the first and second positions.

1 1 . A chuck comprising:

a body that is adapted to be connected to a spindle of a power tool, the body having a threaded axial bore;

a self-tightening screw threaded into the threaded axial bore, the self- tightening screw having a plurality of radially extending slots;

a plurality of jaws, each of the jaws being received into an associated one of the radially extending slots;

a jaw carrier that is rotationally received over a portion of the body, the jaw carrier defining a plurality of longitudinal slots, each of the longitudinal slots receiving a corresponding one of the jaws such that the jaws are moveable both axially and radially relative to the jaw carrier;

a bearing element is disposed between the jaw carrier and the body to facilitate rotation of the jaw carrier relative to the body;

a pawl coupled to one of the jaw carrier and the body, the pawl being movable into a locked position to non-rotatably couple the jaw carrier to the body;

an outer sleeve rotatably mounted about the body and rotatable to move the pawl into the locked position; and

a release mechanism that can be selectively actuated to release tension between the at least one of the body, the jaw carrier and the bearing element when the chuck is in a jammed condition, the release mechanism being configured to selectively reduce tension in the self-tightening screw without rotating the self-tightening screw relative to the body.

12. The chuck of Claim 1 1 , wherein the jaw carrier comprises a first carrier portion, a second carrier and a third carrier portion, wherein the longitudinal jaw slots are formed in the first carrier portion, wherein the second carrier portion is disposed axially between the first and third carrier portions, and wherein the release mechanism is configured to move the second carrier portion axially away from the first carrier portion when clearing the jam condition.

13. The chuck of Claim 12, wherein the first and second carrier portions cooperate to define an outer bearing race into which the bearing elements are received.

14. The chuck of Claim 13, wherein the release mechanism comprises a locking sleeve and a locking element, wherein the locking sleeve is axially movable between a first position, which drives the locking element into the second carrier portion to cause the second carrier portion to seat against the bearing elements, and a second position which permits the locking element to retract from the second carrier portion to cause the second carrier portion to slide away from the bearing elements.

15. The chuck of Claim 14, wherein the release mechanism comprises a push disk that is axially slidably mounted about the body, the push disk being configured to transmit motion to the locking sleeve to move the locking sleeve from the first position to the second position.

16. The chuck of Claim 14, wherein the release mechanism comprises a drive sleeve that is rotatably mounted about the body, the drive sleeve being configured to transmit motion to the locking sleeve to move the locking sleeve from the first position to the second position.

17. The chuck of Claim 16, wherein the drive sleeve comprises a plurality of first ratchet teeth that are meshingly engaged with second ratchet teeth coupled to the locking sleeve.

18. The chuck of Claim 17, wherein the locking sleeve defines a slot with a tapered surface, wherein a pin is received into the slot and disposed against the tapered surface, and wherein the pin is fixedly coupled to the jaw carrier.

19. The chuck of Claim 13, wherein the release mechanism comprises a plurality of wedges that are radially movable between a first, radially inward position, in which the wedges urge the second carrier portion against the bearing elements, and a second, radially outward position.

20. The chuck of Claim 19, wherein the release mechanism further comprises a cam track and a plurality of rollers that are disposed between the cam track and the rollers, the cam track and the rollers being configured to coordinate movement of the wedges between the first and second positions.

21 . A chuck comprising:

a body;

a plurality of jaws;

a threaded element threadably coupled to one of the body and the plurality of jaws;

a plurality of bearing elements in a load path between the jaws and the body, the bearing elements being configured to transmit a load to the body when the jaws are tightened about a tool bit; and

a release mechanism that is configured to selectively move a portion of a bearing race against which the bearing elements are engaged to reduce the load that is transmitted through the bearing elements to the body.

22. A chuck comprising:

a plurality of jaws;

a chuck body;

a rotatable member that is configured to coordinate radial movement of the jaws; and

a plurality of bearing elements in a load path between the jaws and the chuck body, the bearing elements being configured to transmit a load to the body when the jaws are tightened about a tool bit; and

a release mechanism that is configured to selectively move a portion of a bearing race into which the bearing elements are received to reduce the load that is transmitted through the bearing elements to the body.