Patent Publication Number: US-7896357-B2

Title: Universal tool bit shank

Description:
RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 11/322,183, filed Dec. 29, 2005, now pending, titled “Universal Tool Bit Shank,” which is incorporated by reference. 
    
    
     FIELD 
     The present disclosure relates to tools, and more particularly to tool shanks. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. 
     A variety of tool bits are available for use with drivers. However, these tool bits often have unique engagement portions. The drivers also often have a unique tool bit receiving portion. As a result, a tool bit that is able to be coupled to one type of driver may not be able to be coupled to a different type of driver. 
     SUMMARY 
     A universal tool shank can include an elongate body having first and second portions. The first portion can include at least one flat thereon for engagement with a recess in a first tool. The second portion can include at least one protrusion extending radially outwardly therefrom for engagement with a recess in a second tool. The first and second portions can be disposed axially apart from one another. 
     Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. 
         FIG. 1  is a plan view of a tool, a chuck assembly, and a tool bit in accordance with the present disclosure; 
         FIG. 2  is a perspective view of the chuck assembly of  FIG. 1 ; 
         FIG. 3  is a longitudinal or axial cross-sectional view taken generally along line  3 - 3  of  FIG. 1 , illustrating a tool bit prior to insertion into the chuck assembly; 
         FIG. 4  is a longitudinal cross-sectional view similar to that of  FIG. 3 , but illustrating the tool bit fully inserted in the chuck assembly; 
         FIG. 5  is a lateral or radial cross-sectional view, taken generally along line  5 - 5  of  FIG. 4 ; 
         FIG. 6  is a side view of a body portion of the chuck assembly; 
         FIG. 7  is a perspective view of a tool assembly; 
         FIG. 8  is a partial perspective view of a driver; and 
         FIG. 9  is a partial sectional view of an additional driver. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
       FIGS. 1 through 6  depict an exemplary embodiment of a chuck assembly or tool bit holder according to the present disclosure, shown merely for purposes of illustration. One skilled in the art will readily recognize, from the following discussion and the accompanying drawings, that chuck assemblies or bit holders of configurations other than that of this exemplary illustration can also advantageously employ the principles of the present disclosure. 
     In  FIGS. 1 through 6 , an exemplary chuck assembly or bit holder  10  is attachable to a power tool or to a hand tool  18  to be driven for rotation about an axis  12  (shown in  FIG. 3 ). The chuck assembly  10  is adapted to removably receive a tool bit  14  having a generally hex-shaped shank  15  with a circumferential recess  16  formed therein. The tool bit  14  can be any of a number of well-known bits, including drill bits, nut driver bits, screwdriver bits, or other types of fastener driver bits, for example. 
     As best shown in  FIGS. 3 and 6 , the chuck assembly  10  generally includes a body  20 , having a shank portion  22  thereon for mounting the chuck assembly  10  for rotation by a hand tool or a power tool. A hex-shaped socket or bore  24  is formed in the body  20 , with the bore  24  opening axially outwardly toward the front or forward end of the chuck assembly  10 . A pair of annular retainer grooves  26   a ,  26   b  are provided at opposite ends of a cylindrical main body portion  20   a  of the body  20  (as best shown in  FIG. 6 ). A plunger bore  28  extends axially from the hex-shaped socket or bore  24  toward the rear end of the chuck assembly  10 . 
     A generally cylindrical hollow retraction collar  30  surrounds a portion of the radially outer periphery of the body  20  and is axially slidable thereon. The hollow retraction collar or sleeve  30  includes a radially inwardly-directed forward flange  32  slidably surrounding a portion of the body  20 , with a hollow internal bore  34  within the retraction collar  30  opening in an axially-rearward direction and being of a diameter sufficient to slidably surround an annular bearing sleeve  36  mounted on the rear end of the main body portion  20   a  of the body  20 . The bearing sleeve  36  abuts against a retention ring  38  received in the rearward retainer groove  26   a  of the body  20 . 
     The body  20  includes an angular slot  50  formed transversely therein, with the slot  50  extending from the radially outer surface of the body  20  in an axially forward and radially inward direction to communicate with the interior of the hex bore or socket  24 . A generally U-shaped retaining clip  60  has a central base portion  62  and a pair of legs  64  at opposite ends of the central base  62  forming opposite corners  66  thereon. The base  62  of clip  60  is slidably disposed within the angular slot  50 , and the two legs  64  extend around the body  20  to locations thereon that are on an opposite side of the axis  12  from the base  62  and the slot  50 . 
     A coil spring  40  surrounds a portion of the body  20  and is disposed between the body  20  and the retraction collar  30 . The coil spring  40  abuttingly engages the annular bearing sleeve  36  and directly engages the clip  60 . Thus compressed, the coil spring  40  resiliently biases the clip  60  in forward axial and inward radial directions within the slot  50 . Because of this direct abutting engagement with the clip  60  and its legs  64  (as discussed above), the resultant reactive axial force exerted by the clip  60  on the coil spring  40  is directed substantially along the axis  12 , thus keeping the coil spring  40  coaxially aligned with the body  20 . 
     As can best be seen in  FIGS. 3 through 5 , the clip  60  is retracted axially rearwardly and radially outwardly in the slot  50 , during axially rearward retraction of the retraction collar  30 . At the end of this retraction, the corners  66  (at the intersections of the legs  64  with the central base  62 ) move radially outwardly into contact with the internal surface of the internal hollow bore  34  of the retraction collar  30 . This contact substantially prevents further axially rearward movement of the retraction collar  30 , thus substantially minimizing the possibility of over-retraction and subsequent cocking or jamming of the retraction collar  30 . 
     Still further, in accordance with the preferred form of the present invention, the coil spring  40  has at least one bight at each of its forward and rearward ends axially collapsed to form respective forward dead coil bights and rearward dead coil bights. This dead coil end bight arrangement can optionally be provided at either the forward or rearward ends of the coil spring  40 , or preferably at both ends. Such dead coil bights at the ends of the coil spring  40  allow the coil spring  40  to engage the step on the body  20  and the legs  64  of the clip  60 , respectively, in a substantially flat abutting relationship therewith. This, in turn, serves to help maintain the coil spring  40  in a proper, coaxially-aligned relationship with the body  20  and helps eliminate the need for any of the prior art&#39;s intermediate sliding sleeves or other such intermediate members between the coil spring  40  and the clip  60 . Thus, this arrangement helps eliminate the need for a flat portion on such an intermediate sleeve or member and a corresponding flat portion on the body  20  in order to keep such an intermediate sleeve or other such member properly aligned. This dead coil end bight arrangement, along with the other features of the chuck assembly  10  described above, all contribute to the increased simplification and decreased cost of machining and assembling the chuck assembly  10 , as well as helping to minimize the number of required parts. 
     A retention ring  68  is preferably fixed in the forward retaining groove  26   b  at the forward end of the body  20  and thus serves to retain the above-described components in their assembled condition. The retention ring  68  is preferably in the form of a C-shaped clip ring. 
     A plunger  70  is received in the plunger bore  28  of the body  20 . The plunger  28  is cylindrical or capsule shaped including an annular flange portion  72  extending radially outward from a center portion of the plunger  70 . The annular flange portion  72  contacts the generally cylindrical inner wall surface of the plunger bore  28 . A plunger spring  74  is received within the plunger bore  28  and abuts against a rearward wall thereof and against the annular flange  72  of the plunger  70 . A plunger bearing  76  is provided to retain the plunger  70  within the plunger bore  28 . The plunger bearing  76  has an annular ring shape which is received in the forward end of the plunger bore  28  and receives a forward end of the plunger  70  through an annular opening therein. The plunger bearing  76  can be press-fit or otherwise fastened within the end of the plunger bore  28 . The flange  72  of the plunger  70  abuts against the plunger bearing  76  when there is no bit received within the chuck assembly  10 , as best shown in  FIG. 3 . 
     As a bit  14  is inserted into the chuck assembly  10 , as shown in  FIG. 4 , the end of the bit  14  presses against the forward end of the plunger  70  pressing the plunger rearward as illustrated in  FIG. 4 . The plunger is pressed against the spring force of the spring  74  into a retracted position. As the tool bit  14  is pressed inward, the retaining clip  60  is forced to slide rearwardly and radially outwardly in the angular slot  50 , against the bias of the coil spring  40 , in order to allow the bit to be inserted. Once the bit is fully seated in the hex socket  24 , the base portion of the retaining clip  60  is resiliently urged back downward towards the bottom of the angular slot  50  where it engages the circumferential recess  16  formed on the hex shank  15  of the bit  14 . The tool bit  14  is removed from the chuck assembly  10  by the operator sliding the retraction collar  30  axially rearwardly along the body  20  thus compressing the coil spring  40  to allow the retaining clip  60  to retract back up the angular slot  50  and release the tool bit  14  as the tool bit is pressed outward by the plunger  70 . The spring force of the plunger spring  74  is preferably selected so as to press the bit forward enough with the centerline of the bit extending vertically so that the circumferential recess  16  in the hex shank  15  is pressed forward so as to prevent re-engagement by the retaining clip  60  when the retraction collar  30  is released by the operator. However, the spring force is also selected to be weak enough so as not to eject the bit from the hex socket. Specifically, the spring force is preferably weak enough to prevent ejection of the bit when the centerline of the bit is ten degrees below horizontal (−10 degrees from horizontal). Thus, an operator can hold the tool  18  with one hand, pull the retraction collar  30  to a released position with the other hand, and then release the retraction collar and pull the tool bit out of the hex socket  24  while maintaining control of the tool  18  with the first hand. The removal of the bit can be accomplished in this manner while the tool is positional such that the centerline of the bit is above −10 degrees from horizontal without the bit falling out. 
     As seen in  FIGS. 1 and 2 , shank  22  is a universal shank and includes first and second portions  124 ,  126 . The first portion  124  has a generally hexagonally shaped cross-section with flats  128  thereon. Second portion  126  is located between first portion  124  and sleeve  30 . The first portion  124  can optionally be provided with a recessed annular ball groove  124 A provided in the exterior surface as shown in phantom in  FIG. 6 . 
     Second portion  126  includes a generally cylindrical body  132  having a diameter greater than the diameter of first portion  124 . Retaining arms  134  extend radially from cylindrical body  132 . The arms  134  extend generally axially along a portion of the cylindrical body  132 , terminating before first portion  124 . An additional retaining assembly  136  is also located in second portion  126 . 
     Retaining assembly  136  includes a ball  138  and a spring  140  and is retained within recess  142 . Recessed portion  142  includes an outer opening  144  having a diameter less than the diameter of ball  138  and an inner portion  146  having a diameter greater than the diameter of ball  138 . The spring  140  biases the ball  138  radially outwardly, forcing ball  138  against outer opening  144 . Outer opening  144  generally limits the radial travel of ball  138 . Retaining assembly  136  can therefore provide an additional engagement with a receiving bore having a recess therein, as seen in  FIG. 9  and discussed below. 
     Alternatively, as seen in  FIG. 7 , a tool assembly  210  can include a tool member  220  having a shank  222  thereon for mounting the tool assembly  210  for rotation by a hand tool or a power tool. The tool member  220  is shown as a common screwdriver having a head  226  and a shaft  224 . However, it is understood that any number of tools can be substituted for the screwdriver shown in  FIG. 7 . Shank  222  is generally identical to shank  22 , and therefore will not be described in detail. As such, shank  22  is discussed below with the understanding that the following equally applies to shank  222 . 
     Shank  22  is universal due to first and second portions  124 ,  126  being designed to be used with different tools. Shank  22  can be received by a variety of drivers having tool receiving recesses such as those shown in  FIGS. 8 and 9 . 
     As seen in  FIG. 8 , a first driver  230  can include a body  232  having an end surface  234  and a hexagonal shaped recess  236  extending therethrough and into the body  232 . In this arrangement, first portion  124  can extend into recess  236  and second portion  126  can generally abut end surface  234 , thereby providing a driving engagement between driver  230  and chuck assembly  10 . 
     As seen in  FIG. 9 , a second driver  238  can include body  240  having an end surface  242  and a generally cylindrical recess  244  extending therethrough and generally into the body  240 . Axially extending slots  246  are formed in cylindrical recess  244  and include an end surface  248 . A recess  250  is also located in cylindrical recess  244 . Shank  122  can extend into cylindrical recess  244 . Due to its smaller diameter, first portion  124  can extend freely through cylindrical recess  244  and second portion  126  can engage cylindrical recess  244  through arms  134  and ball  138 . Arms  134  can be located within slots  246  and abut end surfaces  248 . Ball  138  can additionally be located within recess  250 .