Abstract:
A chuck for use with a manual or powered driver having a drive shaft, the chuck including a body having a nose section and a tail section, the tail section configured to rotate with a drive shaft of a driver and the nose section having an axial bore formed therein, plurality of jaws disposed within the body in communication with the bore, each of the jaws having a jaw face formed thereon for engagement with a tool shaft, and a visual indicator disposed on the body and including a surface on which is defined a visual indicia that is in operative communication with the jaws so that movement of the jaws to a predetermined position with respect to the bore exposes the indicia to view from outside the chuck and so that movement of the jaws from the predetermined position blocks the indicia from view from outside the chuck.

Description:
CROSS REFERENCE TO RELATED APPLICATION  
         [0001]    The present application claims the benefit of U.S. Provisional Patent Application No. 60/386,187, filed Oct. 24, 2001.  
         BACKGROUND OF THE INVENTION  
         [0002]    The present invention relates generally to chucks for hand, electric or pneumatic power drivers and particularly to quick change chucks.  
           [0003]    Electric and pneumatic tool drivers are well known. Although twist drills are the most common tools on such drivers, the tools may also comprise screw drivers, nut drivers, burrs, mounted grinding stones and other cutting or abrading tools. Since the tool shanks vary in diameter or have a polygonal cross-section, the device usually has an adjustable chuck. The chuck may be attached to the driver spindle by a threaded or tapered bore. A variety of chucks for both hand and power drivers have been developed in the art.  
           [0004]    In an oblique jawed chuck, a chuck body includes three passageways disposed approximately 120 degrees apart from each other. The passageways are configured so that their center lines meet at a point along the chuck&#39;s central axis at a point typically forward of the chuck. The passageways constrain three jaws that are moveable in the passageways to grip a cylindrical or polygonal tool shank displaced approximately along the chuck&#39;s center axis. The chuck includes a nut that rotates about the chuck center and that engages threads on the jaws so that rotation of the nut moves the jaws in either direction within the passageways. The body is attached to the spindle of a driver and is configured so that rotation of the body in one direction with respect to the nut forces the jaws into gripping relationship with the tool shank, while rotation in the opposite direction releases the gripping relationship. The chuck may be operated by a chuck key, or the sleeve may be rotated by hand in a keyless configuration. An example of a keyless chuck is disclosed in U.S. Pat. No. 5,125,673, which is commonly assigned to the present Assignee and the entire disclosure of which is incorporated by reference herein. Various configurations of keyless chucks are known in the art and are desirable in a variety of applications.  
         SUMMARY OF THE INVENTION  
         [0005]    The present invention recognizes and addresses the foregoing considerations, and others, of prior art constructions and methods.  
           [0006]    Accordingly, it is an object of the present invention to provide an improved chuck for a tool driver.  
           [0007]    This and other objects may be achieved by a chuck for use with a manual or powered driver having a drive shaft. The chuck includes a generally cylindrical body member having a nose section and a tail section. The tail section is configured to mate with the drive shaft of the driver, and the nose section has an axial bore formed therein. A plurality of jaws are disposed radially reciprocally within the body in communication with the bore. Each of the jaws has a jaw face formed thereon for engagement with the tool. An annular nut is axially movably disposed about the body in driving engagement with the jaws so that axial movement of the nut with respect to the body drives the jaws toward and away from the axial bore, depending on the direction of the axial movement. The nut defines a threaded outer circumferential surface. A generally cylindrical sleeve is rotatably mounted about the body and defines a threaded inner circumferential surface engaging the threaded outer surface of the nut so that relative rotation between the nut and the sleeve moves the nut axially with respect to the body. The nut and the body tail section are rotationally coupled by an axially aligned, with respect to the chuck body, slot defined on one of the nut and the tail section and an axially aligned rib defined on the other of the nut and the tail section and received by the slot. A first detent is formed in the nut and engages a catch formed on the inner surface of the sleeve between the threads.  
           [0008]    A second detent extends radially into the bore located in the body. The second detent is releasable in a radially outward direction. An elongated tool shaft has a polygonal cross section and defines a circumferential groove. Upon insertion of the tool shaft into the bore so that the groove is aligned with the second detent, the second detent engages the groove and axially retains the tool shaft. When the jaws are moved to a predetermined location, the jaw faces engage flat sides of the tool shaft rotationally locking the tool in place.  
           [0009]    The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one or more embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    A full and enabling disclosure of the present invention, including the best mode thereof to one of ordinary skill in the art, is set forth more particularly in the remainder of the specification, which makes reference to the accompanying figures, in which:  
         [0011]    [0011]FIG. 1 is an exploded view of a chuck in accordance with an embodiment of the present invention;  
         [0012]    [0012]FIG. 2 is a cutaway plan view of the chuck as in FIG. 1;  
         [0013]    [0013]FIG. 3 is cutaway plan view of the chuck as in FIG. 1;  
         [0014]    FIGS.  4  to  6  are cutaway perspective views of a visual indicator and detent of the chuck as in FIG. 1; 
     
    
       [0015]    Repeat use of reference characters in the present specification and drawings is intended to represent same or analogous features or elements of the invention.  
       DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0016]    Reference will now be made in detail to presently preferred embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.  
         [0017]    Referring to FIGS.  1  to  3 , a chuck  10  in accordance with one embodiment of the present invention includes a front sleeve  20 , a rear sleeve  30 , a body  40 , and jaws  50 . Body  40  is generally cylindrical in shape and comprises a nose section  42  and a tail section  44 . An axial bore  46  is formed in nose section  42  and is somewhat larger than the largest tool shank that chuck  10  is designed to accommodate. Tail section  44  defines a threaded bore  48  and is of a standard size to mate with the drive shaft of a powered or hand driver (not shown). Bores  46  and  48  may communicate at a central region of body  40 . While a threaded bore  48  is illustrated, such bore could be replaced with a tapered bore of a standard size to mate with a tapered drive shaft or could be made integrally with the drive shaft.  
         [0018]    Passageways  41  are formed in body  40  to accommodate each jaw. Preferably, three jaws  50  are employed, and each jaw is separated from an adjacent jaw by an arc of approximately 120 degrees. The axes of passageways  41  and jaws  50  are angled with respect to chuck axis  43  but intersect chuck axis  43  at a common point. Each jaw  50  has a tool engaging face  52 , which is generally parallel to chuck body axis  43 .  
         [0019]    Body  40  defines a shoulder  45  against which is received a bearing assembly  60  comprised of a pair of washers  62  and  64  on either side of a caged ball bearing ring  66 . Forward washer  62  bears in an axially forward direction against a shoulder  21  of sleeve  20 , and rearward axial movement of sleeve  20  on body  40  is prevented by shoulder  45  through bearing assembly  60 . Bearing assembly  60  may comprise any suitable construction, for example of the type described in U.S. Pat. No. 5,348,318, incorporated by reference herein, that facilitates relative rotation between sleeve  20  and the body. In contrast to sleeve  20 , rear sleeve  30  is rotationally fixed to body  40 . In the illustrated embodiment, the rear sleeve is pressed onto the body tail section over knurling formed about the body, but it should be understood that the rear sleeve may be attached to the body in any suitable manner.  
         [0020]    A C-clip  68  is received in an annular groove  47  in body  40  to secure sleeve  20  and bearing assembly  60  in the axially forward direction. A nose piece  70  is slidably received over nose section  42  and is yieldably axially restrained by a compressible C-ring  72  as described in more detail below.  
         [0021]    The outer circumferential surface of sleeve  20  may be knurled or may be provided with longitudinal ribs  22  or other protrusions to enable an operator to securely grip the sleeve. Sleeve  20  may be fabricated from a structural plastic such as polycarbonate, a filled polypropylene, for example glass-filled polypropylene, or a blend of structural plastic materials. Other composite materials, for example, such as graphite-filled polymerics, could also be suitable in certain environments. Further, sleeve  20  may be constructed from suitable metals, such as steel. As should be appreciated by one skilled in the art, the materials from which chuck  10  is fabricated may depend on the end use of the power driver, and the above are provided by way of example only.  
         [0022]    An interior surface of sleeve  20  defines female threads  24 . Threads  24  are a modified square thread formation. It should be understood, however, that any suitable thread shape or formation may be employed, for example including a modified buttress thread. The forward faces of threads  24  may be angled, as shown in FIGS. 2 and 3, or may form straight or curved surfaces. Furthermore, threads  24  may define any suitable pitch, for example an eight pitch configuration along the length of sleeve  20 . A recess  26  is formed on the inner surface of sleeve  20  in a land  27  between two adjacent female threads. Recess  26  is used to set jaws  50  at a predetermined location and is explained in greater detail below.  
         [0023]    A driver, in this embodiment a nut  80 , is slidably received over chuck body  40  and has a male thread  82  extending about the nut&#39;s outer circumferential surface. Thread  82  has the same pitch as thread  24  so that when thread  82  is received by thread  24 , relative rotation between sleeve  20  and nut  80  moves nut  80  axially within sleeve  20 . In particular, where nut  80  is molded, thread  82  may have sloped sides, for example at an approximately 5 degree slope, extending from the outer surface of nut  80  to the outer surface of thread  82 .  
         [0024]    Nut  80  includes three equiangularly spaced apart slots  84  extending axially through nut  80  that receive respective end sections  54  of jaws  50 . Slots  84  are generally cylindrical in shape, and end sections  54  have cut-outs  56  on either side of each jaw so that end sections  54  are radially slidable within nut  80 . The interaction of slots  84  and end sections  54  axially secures jaws  50  to nut  80 , so that jaws  50  travel with nut  80  as it moves axially on chuck body  40 , and prevents rotation of jaws  50  about their axes. It should be understood that jaws  50  may be secured to nut  80  in any suitable manner. For example, nut  80  may include slots that extend entirely axially through nut  80 , and jaw ends  54  may extend through slots  84  and rearward of nut  80 . In such an embodiment, a garter spring may extend around all three jaw ends  54  to retain jaws  50  axially to nut  80 .  
         [0025]    Since jaws  50  are received in jaw passageways  41 , the connection between jaw ends  54  and slots  84  prevents nut  80  from rotating about body  40 . Nut  80  is also rotationally coupled to body  40  by a slot/key arrangement between three ribs  49  extending axially along tail section  44  and three respective slots that extend axially along the inner circumference of nut  80  and that slidably receive respective ribs  49 . Thus, even though nut  80  and body  40  are also rotationally coupled by jaws  50  in jaw passageways  41 , the slot/key formation provides further rotational stabilization between the two components. It should be understood that the particular shapes of slots and ribs may vary and that slots or ribs may be defined on either nut  80  or chuck body  40 .  
         [0026]    Because nut  80  is rotationally coupled to chuck body  40 , rotation of sleeve  20  with respect to body  40  moves nut  80  axially with respect to chuck axis  43  by the cooperation between threads  24  and  82 . Depending on the rotational direction of sleeve  20  relative to nut  80 , jaws  50  move axially forward or backward relative to body  40  to an opened or closed position. As jaws  50  move forward toward a closed position, jaw ends  54  move radially inward within nut slots  84 . Conversely, jaw ends  54  move radially outward toward sleeve  20  as nut  80  moves rearwardly in the opening direction.  
         [0027]    A guard ring  88  is received on an outer shelf surface  81  of nut  80  and covers the openings to slots  84 , thereby preventing jaw ends  54  from extending radially outward of slots  84  in an extreme open position and interfering with sleeve thread  24 . Guard ring  88  includes three finger portions  89  that extend axially forward, and radially inward, from the openings at generally the same angle with respect to chuck axis  43  as defined by jaws  50 . Guard ring  88  is maintained in the correct rotational position by flanges  87  that grip opposing surfaces  85  of an axial slot  83  extending through the outer surface of nut  80 .  
         [0028]    Referring to FIGS. 1 and 4- 6 , it can be seen that nut  80  also has a flat shelf surface  81  a where a bore  90  is defined radially therethrough. In order to properly receive guard ring  88 , guard ring  88  also contains a flat surface  88   a  that mates to flat shelf surface  81   a . A bore  88   b  formed in flat portion  88   a  aligns with nut radial bore  90 . The opening of bore  90  is centered in flat shelf surface  81   a  and houses a detent that aides chuck  10  in configuring jaws  50  to rotationally lock a tool  120  in chuck  10 .  
         [0029]    Referring also to FIG. 3, the detent includes a tubular casing  91 , a spring  92  within casing  91 , and a ball  94  biased by the spring radially outward from casing  91 . The rear end of spring  92  engages an enclosed end  93  of casing  91  and traverses a channel  33  formed in a finger  86  of a lock indicator ring  34 . Lock indicator ring  34  is rotatably mounted within rear sleeve  30  and cooperates with multiple openings  32  equally spaced about the circumference of the rear sleeve to visually notify the user that the jaws are in a predetermined desired position, as described in more detail below.  
         [0030]    Channel  33  has three distinct regions: an upper channel  37 , a mid channel  38 , and a lower channel  39 . Upper channel  37  and lower channel  39  run parallel to bore axis  43  and are slightly offset from each other by mid channel  38 , which is formed at an angle from bore axis  43  and in continuous communication with upper channel  37  and lower channel  39 , as shown in FIGS.  4 - 6 . Lock indicator ring  34  also defines indicia  35  equally spaced about its circumference. Indicia  35  can be formed from colored recesses, bumps, circles, etc., as well as areas of distinct shading, cross-hatching or other patterning, texture, or other indicator that is visually distinct from the areas to either side of the indicia on the circumferential surface of lock ring  34 . Lock indicator ring  34  is rotatably coupled within rear sleeve  30  such that indicia  35  align with openings  32  as lock indicator ring  34  is rotated within rear sleeve  30 .  
         [0031]    When installed on the body, rear sleeve  30  and lock indicator ring  34  are positioned so that finger  36  fits between nut  80  and body  40  through a channel  31  formed in the inner circumference of nut  80 . Bore  90  opens into the center of channel  31  so that rear end  93  of casing  91  extends into channel  33  in finger  36 . Channel  31  defines a width larger than the width of finger  36 , so that finger  36  and lock indicator ring  34  can rotate about the chuck axis over a limited arc with respect to nut  80  and, therefore, with respect to body  40  and rear sleeve  30 . The difference between the widths of channel  31  and finger  36  (i.e. the range of rotational movement of ring  34  with respect to the rear sleeve) may vary but should be large enough to permit movement of indicia  35  into and out of the operator&#39;s view in openings  32 . As described below, this movement is controlled by the position of rear end  93  in channel  33  in finger  36  as nut  80  moves axially over body  40 .  
         [0032]    In operation, as sleeve  20  rotates about nut  80 , ball  94  rides on lands  27  between the grooves of threads  24 . Depression  26  formed in land  27  receives ball  94  when tool engaging surfaces  52  of jaws  50  define a predefined diameter. When tool engaging surfaces  52  are in this predetermined position, the diameter is slightly less than the cross width of a tool (preferably a multi-sided tool) that chuck  10  is to receive. For example, the diameter is slightly less than one-quarter inch where the width of the expected tool shafts is one-quarter inch. Ball  94  makes a clicking sound when entering depression  26  and slightly inhibits rotation of sleeve  20 . This notifies the user that jaws  50  are in the predetermined position to receive the tool shank. In addition, lock indicator ring  34  provides a visual indicator regarding whether the jaws have reached the predetermined position. The indicator is controlled through operation of sleeve  20 , which moves nut  80  axially relative to sleeve  20  and body  40 . As nut  80  moves axially on the body, rear end  93  of casing  91  traverses channel  33  as seen in FIGS.  4 - 6 . Keeping in mind that nut  80  is rotationally fixed with respect to body  40  and rear sleeve  30 , casing  91  does not rotate about the chuck axis as it moves up and down the chuck body with the nut. Thus, the casing pushes finger  36  slightly clockwise or counterclockwise about the chuck axis as it traverses channel  31 , depending on the direction of its movement.  
         [0033]    For example, in FIG. 4, casing  91  is located in upper channel  37 , and indicia  35  are just offset from their corresponding openings  32  in the counterclockwise direction. As sleeve  20  is rotated clockwise, nut  80  moves axially forward along body  40  causing jaws  50  to move into bore  46  (FIG. 3) toward the predetermined position. As casing  91  moves up the body with the nut, and referring also to FIG. 5, ball  94  eventually engages depression  26 , thereby causing an audible click and slight resistance to notify the user that the jaws have reached the predetermined position. By this point, casing  91  has moved from the upper channel to the mid channel. Its movement to the angled mid channel forces the lock indicator ring to rotate slightly in the clockwise direction, thereby causing indicia  35  to align with their corresponding openings  32 . This creates a visual indication to the user that the predetermined position has been reached. If the user continues to rotate sleeve  20  in the clockwise direction, ball  94  moves out of depression  26 , and casing  91  moves through channel  33  into lower channel  39 . This further rotates lock indicator ring  34  and moves indicia  35  out of alignment with openings  32 , as shown in FIG. 6.  
         [0034]    A stop  28  may be provided at the rear edge of thread  24  so that a rear edge of thread  82  abuts stop  28  when (i) jaws  50  reach a fully open position or (ii) casing  91  reaches the upper end of upper channel  37 . A similar stop (not shown) may be provided at the front end of thread  24  to stop a forward edge of thread  82  to prevent (i) jaws  50  from binding in the fully closed position when there is no tool in bore  46  or (ii) casing  91  from reaching the lower end of lower channel  39 .  
         [0035]    By rotating sleeve  20 , the user may grip and release a cylindrical or polygonal shaped tool shank through the jaws alone. That is, the user may insert a tool shank into bore  46  (FIG.  3 ) and rotate sleeve  20  so that nut  80  drives the jaws down onto the shank and so that the jaws tighten onto the shank, regardless of the engagement of detent ball  94  in recess  26  and the activation of the visual indicator along the way. On the other hand, the operator may use these devices in locating the jaws to receive a tool shank of a predetermined size. For example, there the chuck is configured to receive a quarter inch polygonal (e.g. hexagonal) bit in this manner, the ball detent and visual indicator may locate the position where the jaws&#39; engaging surface define a diameter slightly less than one quarter inch. The difference in diameter accounts for any tolerances in the chuck, and as the bit is pushed into the chuck bore, the bit&#39;s flat sides push the jaws slightly back against those tolerances.  
         [0036]    Once the polygonal bit is pushed into the bore, the jaws secure the bit against rotation but may not necessarily provide sufficient axial restraint without further tightening. To avoid the need for hand-tightening through additional rotation of sleeve  20 , the jaws my be part of a quick change mechanism that includes a detent that axially restrains the bit in the chuck bore.  
         [0037]    Referring to FIGS. 1 and 2, a detent  100  includes a lever  101  that engages a catch in a tool shaft  120 , for example an annular groove  122 . Lever  101  pivots about a pin  105  within a cartridge  104 , which is pressed into an axial slot  98  extending radially through body  40  and opening into bore  46 . A spring  106  winds about a pin  109  and has a first end  107  resting against a rearward edge of cartridge  104  and a second edge  108  that rests against a rearward end  102  of lever  101  so that spring  106  biases rearward end  102  into bore  46 . Due to the pivotal connection of lever  101  at pin  105 , a forward end  103  of lever  101  is biased radially outward against an inner surface  75  of nose piece  70 .  
         [0038]    When tool shank  120  of sufficient cross-sectional diameter is inserted into bore  46 , a leading edge  123  of tool shank  120  engages rearward end  102  and pushes rearward end  102  radially outward against the bias of spring  106  so that rearward end  102  passes over tool shank  120  as tool shank  120  is inserted into bore  46 . When shank  120  passes to a sufficient depth into bore  46 , spring  106  pushes rearward end  102  into annular groove  122 . If tool shank  120  is pulled axially forward, groove  122  engages rearward end  102 , tending to pivot lever  101  about pin  105 . This rotation is, however, prevented by the engagement of forward end  103  against the inner surface  75  of nosepiece  70 . Thus, detent  100  retains tool shank  120  axially in bore  46 .  
         [0039]    Once shank  120  is inserted into bore  46  and locked into place, it may be released by pulling nosepiece  70  forward so that a cam surface  74  at the rear of the nosepiece pushes forward end  103  of lever  101  radially inward within cartridge  104 . This pivots lever  101  about pin  105  so that rearward end  102  moves radially outward out of groove  122 , allowing tool shank  120  to be removed from chuck  10 .  
         [0040]    Lever  101  also assists in retaining nosepiece  70  on body  40 . Cam surface  74  is sloped such that forward end  103  of lever  101 , which is biased into inner surface  75  by spring  106 , tends to urge nosepiece  70  axially rearward into its position shown in FIG. 2. Furthermore, C-ring  72  is biased radially outward against a second cam surface  76 . When nosepiece  70  is pulled forward, ring  72  pushes outward against cam surface  76  and, when the operator releases nosepiece  40 , urges nosepiece  40  axially rearward to its position as shown in FIG. 2.  
         [0041]    While one embodiment of the present invention has been described above, it should be understood that any and all equivalent realizations of the present invention are included within the scope and spirit thereof. Thus, the depicted embodiment is presented by way of example only and is not intended as a limitation of the present invention. For example, either of the audible and visual indicators may be used without the other and/or without the front detent. Therefore, it is contemplated that any and all such embodiments are included in the present invention as may fall within the literal or equivalent scope of the appended claims.