Abstract:
A “snap-in” bit chuck assembly for a rotary hand or powered tool, includes a body having a hex shank at its rearward end and a retraction collar slidably disposed on the body. The body has a coaxial hex socket formed therein to allow a tool bit to be inserted thereinto. A coil spring biases the retraction collar forwardly and biases a retaining clip toward the bottom of an angular slot formed in the body. The bit is removed by sliding the retraction collar rearwardly, to compress the coil spring and allow the retaining clip to retract back up the slot. The bit is biased out of a locked position by a plunger that ensures that the bit remains disengaged when the retraction collar is released.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims the benefit of U.S. Provisional Application Ser. No. 60/390,021, filed on Jun. 18, 2002. The disclosure of the above application is incorporated herein by reference. 

   FIELD OF THE INVENTION 
   The invention relates generally to power or hand tool bit holders, variously known as “auxiliary chucks”, “chucks”, or “adapters”, for removably receiving tool bits, such as fastener drivers, drill bits, or the like, for rotation therewith when the power tool is actuated or the hand tool is manually rotated. More particularly, the present invention relates to chuck assemblies or adapters configured for rapid and easy insertion and removal of a tool bit. 
   BACKGROUND AND SUMMARY OF THE INVENTION 
   Auxiliary chucks for power and hand tools have become increasingly common, especially as the need and desirability of wider versatility in the use of power tools and hand tools has increased. Such auxiliary chucks allow the hand or power tool to be used with any of a number of interchangeable bits. This, in turn, has resulted in demands for greater speed, convenience and ease of insertion and removal of tool bits from such chucks. 
   In one exemplary type of such conventional quick-release chucks, one or more detent balls are positioned within a hollow, barrel-shaped tool bit holder body and are resiliently biased into engagement with a circumferentially-extending groove or recess on the shank of the tool bit. Although this basic design has performed well, chuck assemblies or bit holders of this type have been found to be inordinately expensive and difficult to manufacture due to the relatively large number of parts required, as well as frequently requiring the operator to actuate a sleeve, collar or other component part during both the insertion and the removal of the tool bit. 
   Accordingly, the present invention seeks to provide a simple, relatively inexpensive quick-acting chuck assembly or bit holder that requires the operator to actuate its components only upon tool bit removal. A “snap-in” type of chuck assembly is provided for a drill, driver, or other rotary hand or powered tool, with the chuck assembly including a generally cylindrical body having a hex shank at its inner or rearward end for rotatable attachment to a drill or driver. A hollow cylindrically-stepped retraction collar or sleeve is slidably disposed for movement in an axial direction on a forward portion of the body, and the body has a coaxial hollow hex socket or bore formed therein which opens toward the outer or forward end of the chuck, in order to allow a tool bit to be inserted into the chuck assembly for rotation therewith. 
   An angular slot, extending in a radially-inward and axially-forward direction, is formed in the body, providing communication between the radially outer periphery of the body and the internal hollow hex bore. A coil spring surrounds the body and is disposed inside the retraction collar, with the inner or rearward end of the spring engaging a shoulder on the body and with the outer or forward end resiliently biasing the retraction collar forwardly and biasing a retaining clip radially inwardly and axially forwardly toward the bottom or inner end of the angular slot where it intersects with the body&#39;s hollow hex bore. 
   As a tool bit is snapped into the chuck&#39;s socket, this retaining clip, which is preferably of a generally U-shaped configuration, is forced to slide rearwardly and radially outwardly in the angular slot, against the bias of the coil spring, in order to allow the bit to be inserted. Once the bit is fully seated in the hex socket, the base portion of the U-shaped clip is resiliently urged back down toward the bottom of the angular slot where it engages the circumferential recess formed on the hex shank of the bit, thus retaining the bit in the hex socket or bore where it can be rotatably driven by the drill or driver to which the chuck assembly or bit holder is attached. The tool bit is removed from the chuck assembly by the operator sliding the retraction collar axially rearwardly along the body, thus compressing the coil spring to allow the retaining clip to retract back up the angular slot and release the tool bit so that the tool bit can be removed from the hex socket. 
   In preferred forms of the present invention, a plunger is mounted at the inner most end of the hex socket or bore. The plunger is spring biased to provide a force opposing the hex shank of the bit. The spring force is preferably selected so as to press the bit forward enough so that the circumferential recess in the hex shank is pressed forward so as to prevent re-engagement by the retaining clip when the retraction collar is pulled to a release position and subsequently released. However, the spring force is also selected to be weak enough so as not to eject the bit from the hex socket. Thus, an operator can hold the tool with one hand, pull the retraction collar to a release position with the other hand and then release the retraction collar and pull the tool bit out of the hex socket while maintaining control of the tool with the first hand. 
   Additional objects, advantages, and features of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
       FIG. 2  is a perspective view of the chuck assembly according to the principles of the present invention; 
       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 ; and 
       FIG. 6  is a side view of a body portion of the chuck assembly. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 through 6  depict an exemplary preferred embodiment of a chuck assembly or tool bit holder according to the present invention, 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 invention. 
   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 , preferably having a hex shank  22  thereon for mounting the chuck assembly  10  for rotation by a hand tool or a power tool. A preferred 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  26  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. 
   The foregoing discussion discloses and describes merely exemplary embodiments of the present invention for purposes of illustration only. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims, that various changes, modifications, and variations can be made therein without departing from the spirit and scope of the invention as defined in the following claims. For example, the U-shaped clip-type locking mechanism could be replaced with a ball-type locking mechanism as is well known in the art.