Abstract:
A chuck with a generally cylindrical body having a tail section configured to receive a drive shaft of a driver and a nose section having an axial bore formed therein. A plurality of jaws is movably disposed with respect to the body. A threaded spindle is rotatably connected to the body and operatively engages the jaws. A first ring is fixedly mounted about the body and has a first plurality of teeth. An inner sleeve is rotatably mounted about the tail section and has an open portion. A second ring that has at least one protrusion that mates with the corresponding open portion and extends outwardly from the inner sleeve and the ring has a second plurality of teeth. An outer sleeve is placed concentrically around the inner sleeve and contains a lock groove that the protrusion of the second ring is situated inside the lock groove.

Description:
CLAIM OF PRIORITY 
     The present invention claims priority to U.S. Provisional Patent Application No. 61/073,419, entitled “Self Tightening Chuck with an Axial Lock”, filed Jun. 18, 2008, the entire disclosure of which is incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention is directed to a chuck adapted to releasably hold a tool bit, such as a drill bit, of a manually or power-operated drill, or like rotary tool. 
     BACKGROUND OF THE INVENTION 
     Hand, 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 may be of varying diameter or of a polygonal cross-section, the device is usually provided with a chuck that is adjustable. The chuck is often attached to the driver by a threaded or tapered bore. 
     A variety of chucks have been developed in the art. 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 axis forward of the chuck. The passageways constrain three jaws that are movable in the passageways to grip a cylindrical or polygonal tool shank displaced approximately along the chuck 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 drive shaft of a driver and is configured so that rotation of the body in one direction with respect to the nut forces the jaw into gripping relationship with the tool shank, while rotation in the opposite direction releases the gripping relationship. The chuck may be keyless if it is rotated by hand. Various configurations of keyless chucks are known in the art and are desirable for a variety of applications. 
     SUMMARY OF THE INVENTION 
     In one embodiment of the present invention, a chuck for use with a manual or power driver having a rotatable shaft, the chuck having a generally cylindrical body having a central longitudinal axis, a nose section, and a tail section. The tail section is configured to rotate with the drive shaft and the nose section has an axial bore formed therein. The chuck further has a plurality of jaws movably disposed with respect to the body in communication with the axial bore. The chuck further has a threaded spindle rotatably connected to the body and is in driving engagement with the jaws so that rotation of the threaded spindle in a locking direction moves the jaws toward the central longitudinal axis and rotation of the threaded spindle in an unlocking direction moves the jaws away from the central longitudinal axis. The chuck also has a first ring fixedly mounted about the body and placed intermediate the nose and tail section, the first ring has a first plurality of teeth. The chuck also has an inner sleeve rotatably mounted about the tail section of the body, the inner sleeve having at least one open portion proximate the tail section of the chuck. The chuck further has a second ring having at least one protrusion, where the at least one protrusion mates with the corresponding at least one open portion and extends outwardly from the inner sleeve. The chuck also having an outer sleeve rotatably mounted about the tail section and concentrically situated outside the inner sleeve, the outer sleeve having at least one lock groove with a locked end and an unlocked end, where the locked end extends further in a longitudinal direction toward the nose section than the unlocked end of the at least one lock groove. Where the at least one lock groove is arranged so that the at least one protrusion of the second ring is in contact with the at least one lock groove such that when the at least one protrusion is situated adjacent the locked end of the at least one lock groove, the first plurality of teeth of the first ring engage the second plurality of teeth of the second ring. 
     In a further embodiment of the invention, a chuck for use with a manual or power driver having a rotatable drive shaft, the chuck having a generally cylindrical body having a central longitudinal axis, a nose section, and a tail section, the tail section is configured to rotate with the drive shaft and the nose section has an axial bore formed therein. The chuck further has a plurality of jaws movably disposed with respect to the body in communication with the axial bore. The chuck further has a threaded spindle rotatably connected to the body and in driving engagement with the jaws so that rotation of the threaded spindle in a locking direction moves the jaws toward the central longitudinal axis and rotation of the threaded spindle in an unlocking direction moves the jaws away from the central longitudinal axis. The chuck also has an annular array of teeth formed about the body and placed intermediate the nose end tail section, where the annular array of teeth have a plurality of radially outward extending teeth. The chuck also has an inner sleeve rotatably mounted about the tail section of the body and the inner sleeve having an axially extending open section. The chuck further has a sliding lock situated within the open section of the inner sleeve, where the sliding lock has a protrusion that extends outwardly away from the body and a locking tooth that extends inwardly towards the body. A spring is situated within the open section of the inner sleeve, and the spring and sliding lock are configured such that the spring applies biases the sliding lock rearwardly toward the tail section. The chuck also has an outer sleeve rotatably mounted about the tail section and concentrically situated outside the inner sleeve, the outer sleeve having, a lock groove with a locked end and an unlocked end, where the locked end extends further in a longitudinal direction rearwardly toward the tail section than the unlocked end and where the lock groove is arranged to receive the protrusion of the sliding lock such that when the protrusion is situated adjacent the locked end of the lock groove, the radially inward extending lock tooth of the sliding lock lockingly engages the annular array of teeth formed about the body. 
     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 
       A full and enabling disclosure of the present invention, including the best mode thereof directed to one of ordinary skill in the art, is set forth in the specification, which refers to the appended figures, in which: 
         FIG. 1  is a cross-sectional view of a chuck in the locked position, in accordance with a first embodiment of the present invention; 
         FIG. 2  is a cross-sectional view of the chuck, as shown in  FIG. 1 , in the unlocked position; 
         FIG. 3  is an exploded perspective view of the chuck, as shown in  FIG. 1 ; 
         FIG. 4  is a perspective view of the outer sleeve of the chuck, as shown in  FIG. 1 , wherein a portion of the outer sleeve is removed; 
         FIG. 5A  is a perspective view of the outer sleeve and the second lock ring of the chuck, as shown in  FIG. 1 , wherein the second lock ring is in the locked position; 
         FIG. 5B  is a perspective view of the outer sleeve and the second lock ring of the chuck, as shown in  FIG. 1 , wherein the second lock ring is in the locked position; 
         FIG. 6  is a cross-sectional view of a chuck in a locked position, in accordance with a second embodiment of the present invention; 
         FIG. 7  is a cross-sectional view of the chuck, as shown in  FIG. 6 , in the unlocked position; 
         FIG. 8  is a cross-sectional view of the chuck, as shown in  FIG. 6 , taken along line  8 - 8  of  FIG. 7 ; 
         FIG. 9  is an exploded perspective view of the chuck, as shown in  FIG. 6 ; 
         FIG. 10A  is a partial perspective view of the chuck as shown in  FIG. 6 , in a locked position, wherein the outer sleeve has been removed; 
         FIG. 10B  is a partial perspective view of the chuck as shown in  FIG. 6 , in an unlocked position, wherein the outer sleeve has been removed; 
         FIG. 11A  is a perspective view of the nose section and the body of the chuck, as shown in  FIG. 6 , in a locked position; 
         FIG. 11B  is a perspective view of the nose section and the body of the chuck, as shown in  FIG. 6 , in an unlocked position; 
         FIG. 12A  is a front perspective view of the outer sleeve of the chuck, as shown in  FIG. 6 ; and 
         FIG. 12B  is a back perspective view of the outer sleeve of the chuck, shown in  FIG. 6 . 
     
    
    
     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 INVENTION 
     One of ordinary skill in the art will understand that the present discussion is a description of exemplary embodiments only, and is not intended as limiting the broader aspects of the present invention, which broader aspects are embodied in the exemplary construction. A repeat use of reference characters in the present specification and drawings represents the same or analogous features or elements of the invention. 
     First Embodiment 
     Referring generally to  FIGS. 1 through 5 , an embodiment of a chuck  10  for a rotary tool in accordance with a first embodiment of the present invention is shown. Chuck  10  includes an outer sleeve  12 , an inner sleeve  14  and a plurality of jaws  16 . Chuck  10  is generally cylindrical in shape and includes a nose or forward section  18  at its front end and a tail or rearward section  20  at its back end. 
     Forward section  18  of chuck  10  generally comprises an inner and an outer nosepiece  22  and  24 , respectively, plurality of jaws  16 , and a threaded spindle  26  including a head  28 . Both inner and outer nosepieces  22  and  24  are hollow and each is conical in shape at its front end and cylindrical in shape at its back end. Further, each includes a threaded portion  23  and  25  at its back end. Inner nosepiece  22  is situated within outer nosepiece  24  concentrically at their back ends, and their front ends are in contact with one another. 
     Jaws  16  are movably received on inner nosepiece  22  and can be retracted within inner nosepiece  22  or projected outwardly from the front end of inner nosepiece  22  by means of threaded spindle  26 . Jaws  16  are slidably received within guide slots  30  which are formed on inner nosepiece  22  intermediate its front and back ends. The back ends of jaws  16  are non-rotatably, yet radially slidably, fixed to head  28  of threaded spindle  26 , and all are located within both inner and outer nosepieces  22  and  24 . 
     Rearward section  20  of chuck  10  generally includes a body  32 , inner sleeve  14  and outer sleeve  12 . Outer sleeve  12  forms the outer portion of reward section  20  of chuck  10 . Inner sleeve  14  is located within outer sleeve  12  and body  32  is located within both inner sleeve  14  and outer sleeve  12 . Outer sleeve  12 , inner sleeve  14  and body  32  are concentric. Body  32  includes a threaded bore  34  at its front end which threadably receives threaded spindle  26 . 
     An annular bearing groove  35  is located proximate the front end of body  32 . A corresponding annular bearing groove  36  is formed on the inner surface of inner sleeve  14 . Ball bearings are received within bearing grooves  35  and  36  and aid in the rotation of body  32  relative to the other components of chuck  10 . Body  32  additionally includes, intermediate the front and back ends, a first lock ring  38  that is axially and non-rotatably fixed to the outside of body  32 . The first lock ring  38  includes an annular array of axially rearwardly extending teeth  39 , each with a first side  40  and a second side  41 . Each first side  40  has a slope approaching 90°, and each second side  41  has a slope that is approximately 45°. Body  32  further includes a bore  42  formed in its back end and which is of standard size to mate with the drive shaft of a powered or hand driver (not shown). 
     Inner sleeve  14  includes a first threaded surface  44  formed on its inner surface adjacent its front end and a second threaded surface  46  formed on its outer surface adjacent its front end. First threaded surface  44  receives threaded surface  25  formed at the back end of inner nosepiece  22  and second threaded surface  46  receives threaded surface  23  formed at the back end of outer nosepiece  24 . Inner sleeve  14  is therefore non-rotatably fixed to both inner and outer nosepieces  22  and  24  such that they rotate as a single unit about body  32 . As best seen in  FIGS. 1  though  3 , the back end of inner sleeve  14  includes slots  48  formed opposite to each other. Further, the outer portion of inner sleeve  14  contains a flat  50  and a recess  52  which receives a detent spring  54 . Flat  50  is a recessed portion including an “unlocked” end  50   a  and a “locked” end  50   b . Detent spring  54  includes a left and right end formed into loops  56  to receive rods (not shown) to hold detent spring  54  within recess  52 . Detent spring  54  further includes a raised portion  58  which is located intermediate the left and right ends of detent spring  54  and extends radially outwardly therefrom. 
     Slots  48  of inner sleeve  14  receive tabs  60  of a second lock ring  62  that is axially movable with regard to body  32 . Tabs  60 , like slots  48 , are located opposite each other. Second lock ring  62  is made up of axially forwardly extending teeth  64 , each with a first side  66  and a second side  68 . Each first side  66  has a slope approaching 90° and each second side  68  has a slope that is approximately 45°. A spring  70  is located at the back portion of second lock ring  62  and is in communication at its back end with a retainer  72  that keeps spring  70  in place such that spring  70  biases second lock ring  62  axially forward on body  32 . 
     Outer sleeve  12 , as stated above, is situated around inner sleeve  14  and is of a suitable circumference such that, as shown in  FIGS. 5A and 5B , tabs  60  of second lock ring  62  and raised portion  58  are in contact with the inner surface of outer sleeve  12 . Tabs  60  of second lock ring  62  are situated within a pair of lock grooves  74  located on the inner portion of outer sleeve  12 . Lock grooves  74  are recesses within the inner surface of outer sleeve  12  and contain an “unlocked” end  74   a  and a “locked” end  74   b . Locked end  74   b  of lock groove  74  is formed by a recess that extends further longitudinally along the inner wall of outer sleeve  12  toward its front end than the recess that forms unlocked end  74   a  of each lock groove  74 . A camming surface  74   c  extends between unlocked end  74   a  and locked end  74   b . As best seen in  FIG. 4 , raised portion  58  is allowed to travel between two detent depressions  76   a  and  76   b  on the inner surface of outer sleeve  12 , one being an “unlocked” detent depression  76   a  and the other a “locked” detent depression  76   b . As well, the inside portion of outer sleeve  12  includes a stop  78 . Stop  78  is a protrusion which extends into flat  50  of inner sleeve  14  and engages either of the opposing sides of flat  50  when outer sleeve  12  is rotated between the locked and unlocked positions, as described below. 
     The resting positions for outer sleeve  12  of chuck  10  are either the locked or unlocked positions. The unlocked position is defined when tabs  60  of second lock ring  62  are situated within unlocked ends  74   a  of lock grooves  74  of outer sleeve  12 . As stated above, unlocked end  74   a  of each lock groove  74  does not extend as far longitudinally along the inner surface of outer sleeve  12  as does locked end  74   b . With tabs  60  of second lock ring  62  positioned at unlocked ends  74   a  of lock grooves  74 , second lock ring  62  is urged rearwardly against spring  70 , causing spring  70  to compress and teeth  64  of second lock ring  62  to be disengaged from teeth  39  of first lock ring  38 . Further, in the unlocked position, the raised portion  58  of detent spring  54  is situated within unlocked detent depression  76   a . As well, stop  78  of outer sleeve  12  is positioned such that it is in contact with unlocked end  50   a  of flat  50 . In the unlocked position, when viewing the chuck from the rear, outer sleeve  12  cannot be turned further in a clockwise direction relative to inner sleeve  14 . Further movement of outer sleeve  12  in the clockwise direction relative to inner sleeve  14  is prevented by interaction of tabs  60  with unlocked ends  74   a  of respective lock grooves  74  and stop  78  with unlocked end  50   a  of flat  50 . 
     To operate chuck  10 , a user, when viewing chuck  10  from the rear, turns outer sleeve  12  in a counterclockwise, or tightening, direction. This rotation of outer sleeve  12  causes inner sleeve  14  and inner and outer nosepieces  22  and  24  to all rotate together in the same direction about body  32 . As such, jaws  16  rotate with inner sleeve due to interaction with guide slots  30 . Because jaws  16  are non-rotatably fixed to head  28  of spindle  26 , spindle  26  is rotated within threaded bore  34  of body  32 , subsequently causing jaws  16  to move forward and together to clamp onto the shank of the tool bit (not shown). When jaws  16  make contact with the tool bit, inner sleeve  14  and inner and outer nosepieces  22  and  24  can no longer rotate, leaving only outer sleeve  12  to move. Outer sleeve  12  continues to move in the tightening direction relative to inner sleeve  14  until it is in the locked position. 
     The locked position is defined by tabs  60  of second lock ring  62  being situated within locked ends  74   b  of lock groove  74 . As outer sleeve  12  moves from the unlocked to the locked position, tabs  60  move from unlocked end  74   a  along camming surface  74   c  to locked end  74   b  of lock grooves  74 . As such, spring  70  biases second lock ring  62  toward the front end of outer sleeve  12  since locked end  74   b  of lock groove  74  is closer to the front end of outer sleeve  12  than is the unlocked end  74   a . The movement of second lock ring  62  closer to the front of chuck  10  due to the biasing force of spring  70  causes first and second sides  66  and  68  of teeth  64  of second lock ring  62  to engage the corresponding first and second sides  40  and  41  of teeth  39  of first lock ring  38 , which is fixed to body  32 . Additionally, as outer sleeve  12  is rotated from the unlocked position to the locked position, raised portion  58  of detent spring  54  moves to locked detent depression  76   b , and stop  78  of outer sleeve  12  moves from unlocked end  50   a  of flat  50  to locked end  50   b . The engagement of the teeth of first and second lock rings  38  and  62  prevents rotation of outer sleeve  12 , inner sleeve  14 , and first and second nosepieces  22  and  24  relative to body  32  in the clockwise, or opening, direction. Note, however, that continued rotation about body  32  in the counterclockwise, or tightening direction, is still possible. More specifically, as teeth  64  of second lock ring  62  rotate in a tightening direction, second side  68  of teeth of second lock ring  62  repeatedly slip over teeth  39  of first lock ring  38  causing a clicking or ratcheting sound as each second side  68  of teeth  64  of second lock ring  62  falls against each subsequent second side  41  of teeth  34  of first lock ring  38 . The position of raised portion  58  of detent spring  54  within locked detent depression  76   a  prevents inadvertent rotation of outer sleeve  12  relative to inner sleeve  14  in the opening direction. As such, chuck  10  will remain locked until a user rotates outer sleeve  12  in the opening direction with enough force to cause detent spring  54  to move from locked detent depression  76   b  to unlocked detent depression  76   a , as described below. 
     To open chuck  10 , starting from the locked position, a user, when viewing chuck  10  from the rear, turns outer sleeve  12  in a clockwise, or loosening direction. As outer sleeve  12  begins to rotate, detent spring  54  is disengaged from locked detent depression  76   b  and stop  78  moves from locked end  50   b  of flat  50  to unlocked end  50   a , at which point detent spring  54  engages unlocked detent depression  76   a . As outer sleeve  12  rotates relative to inner sleeve  14 , tabs  60  of second lock ring  62  are urged rearwardly by camming surfaces  74   c  of respective lock grooves  74  toward unlocked ends  74   a  of each groove, thereby causing second lock ring  62  to move rearwardly against the spring force of spring  70 . Once teeth  64  of second lock ring  62  are no longer engaged with teeth  39  of first lock ring  38 , outer sleeve  12 , inner sleeve  14 , and inner and outer nosepieces  22  and  24  start to rotate as a unit about body  32 . As such, jaws  16  are disengaged from the shank of the tool bit, and chuck  10  can be fully opened. 
     Second Embodiment 
     Referring generally to  FIGS. 6 to 12 , an embodiment of a chuck  100  for a rotary tool in accordance with a second embodiment of the invention is shown. Chuck  100  includes an outer sleeve  102 , an inner sleeve  104  and a plurality of jaws  106 . Chuck  100  is generally cylindrical in shape and includes a nose or forward section  108  at its front end and a tail or rearward section  110  at its back end. 
     Forward section  108  of chuck  70  generally includes an inner and an outer nosepiece  112  and  114 , respectively, plurality of jaws  106 , and a threaded spindle  116  including a head  118 . Both inner and outer nosepieces  112  and  114  are hollow and each is conical in shape at its front end and cylindrical in shape at its back end. Further, each includes a threaded portion  113  and  115  at its back end. Inner nosepiece  112  is situated within outer nosepiece  114  concentrically at their back ends, and their front ends are in contact with one another. 
     Jaws  106  are movably received on inner nosepiece  112  and can be retracted within inner nosepiece  112  or projected outwardly from the front end of inner nosepiece  112  by means of threaded spindle  116 . Jaws  106  are slidably received within guide slots  120  which are formed on inner nosepiece intermediate its front and back ends. The back ends of jaws  106  are non-rotatably, yet radially slidably, fixed to head  118  of threaded spindle  116 , and all are located within both inner and outer nosepieces  112  and  114 . 
     Rearward section  110  of chuck  100  generally includes a body  122 , inner sleeve  104  and outer sleeve  102 . Outer sleeve  102  forms the outer portion of rearward section  110  of chuck  110 . Inner sleeve  104  is located within outer sleeve  102  and body  122  located within both outer sleeve  102  and inner sleeve  104 . Outer sleeve  102 , inner sleeve  104 , and body  122  are concentric. Body  122  includes a threaded bore  124  at its front end which threadably receives threaded spindle  116 . 
     An annular bearing groove  126  is located proximate the front end of body  122 . A corresponding annular bearing groove  128  is formed on the inner surface of inner sleeve  104 . Ball bearings  130  are received within bearing grooves  126  and  128  and aid in the rotation of body  122  relative to the other components of chuck  100 . Body  122  additionally includes, on the outer portion of body  122  and intermediate the front and back ends of body  122 , an annular array of locking teeth  132  formed on the outer surface of body  122 . The teeth  136  of the annular array are radially outwardly extending, each with a first side and a second side. Each first side has a slope approaching 90° and second side has a slope that is approximately 45°. Body  122  further includes a bore  142 , which is of standard size to mate with the drive shaft of a powered or hand driver (not shown). 
     Inner sleeve  104  includes a first threaded surface  144  formed on its inner surface adjacent its front end and a second threaded surface  146  formed on its outer surface adjacent its front end. First threaded surface  144  receives threaded surface  113  formed at the back end of inner nosepiece  112  and second threaded surface  146  receives threaded surface  115  formed at the back end of outer nosepiece  114 . Inner sleeve  104  is therefore non-rotatably fixed to both inner and outer nosepieces  112  and  114  such that they rotate as a single unit about body  122 . Inner sleeve  104  includes a sliding lock  144  with a protrusion  150  extending radially outward therefrom. Sliding lock  148  is allowed to travel along a sliding lock track  152  and has a lock tooth  154  to engage annular array of locking teeth  132  of body portion  122  when in the locked position. Within sliding lock track  152  is a spring  156  that is located to restrict the movement of sliding lock  148  and to help in keeping sliding lock  148  in position. The spring  156  is held in place on the track  152  by a pin  157  that extends the length of track  152  and fits through sliding lock  148  and spring  156 . Inner sleeve  104  additionally includes a flat  158 . Flat  158  is a recessed portion including an “unlocked” end  158   a  and a “locked” end  158   b . Inner sleeve  104  further contains a recess  160  that is configured to receive a detent spring  155  with a raised portion  155   a . Detent spring  155  is held in place by rods  162  which fit through holes  164  located within recess  160  and extend through the loop ends of detent spring  155 . 
     Outer sleeve  102 , as stated above, is situated around inner sleeve  104  and is of a suitable circumference such that protrusion  150  of sliding lock  148  and the raised portion of the detent spring  155  are in contact with the inner surface of outer sleeve  102 . Protrusion  150  of sliding lock  148  is situated within a lock groove  166  located on the inner surface of outer sleeve  102 . Lock groove  166  is a recess within the inner surface of outer sleeve  102  and contains an “unlocked” end  166   a  and a “locked” end  166   b . Unlocked end  166   a  of lock groove  166  is formed by a recess that extends further longitudinally along the inner wall of outer sleeve  102  toward its front end than the recess that forms locked end  166   b  of lock groove  166 . A camming surface  166   c  extends between unlocked end  166   a  and locked end  166   b . Raised portion  155   a  of detent spring  155  is allowed to travel between two detent depressions  168   a  and  168   b  on the inside surface of outer sleeve  102 , one being an “unlocked” detent depression  168   a , and the other a “locked” detent depression  168   b . Finally, the inside portion of outer sleeve  102  includes a stop  170 . Stop  170  is a protrusion which extends into flat  158  of inner sleeve and engages either of the opposing sides of flat  158  when outer sleeve  102  is rotated between the locked and unlocked positions, as described below. 
     The resting positions for outer sleeve  102  of chuck  100  are either the locked or unlocked position. The unlocked position is defined when the protrusion  150  of sliding lock  148  is situated within unlocked end  166   a  of lock groove  166  of outer sleeve  102 . As stated above, unlocked end  166   a  of lock groove  166  extends further longitudinally along the inner surface of outer sleeve  102  toward its front end than does locked end  166   b . With protrusion  150  of sliding lock  148  positioned at unlocked end  166   a  of lock groove  166 , sliding lock  104  is urged forwardly against spring  156 , causing spring  156  to compress and lock tooth  154  to be disengaged from locking teeth  132  of body  122 . Further, in the unlocked position, raised portion  155   a  of detent spring  155  is situated within unlocked detent depression  168   a . As well, stop  170  of the outer sleeve  102  is positioned such that it is in contact with unlocked end  158   a  of flat  158 . In the unlocked position, when viewing the chuck from the rear, outer sleeve  102  cannot be turned further in a clockwise direction relative to inner sleeve  104 . Further movement of outer sleeve  102  in the clockwise direction relative to inner sleeve  104  is prevented by interaction of protrusion  150  with unlocked end  166   a  of lock groove  166  and stop  170  with unlocked end  158   a  of flat  158 . 
     To operate chuck  100 , a user, when viewing chuck  100  from the rear, turns outer sleeve  102  in a counterclockwise, or tightening, direction. This rotation of outer sleeve  102  causes inner sleeve  104  and inner and outer nosepieces  112  and  114  to all rotate together in the same direction about body  122 . As such, jaws  106  rotate with inner sleeve  104  due to interaction with guide slots  120 . Because jaws  106  are non-rotatably fixed to head  118  of spindle  116 , spindle  116  is rotated with threaded bore  124  of body  122 , subsequently causing jaws  106  to move forward and together to clamp onto the shank of the tool bit (not shown). When jaws  106  make contact with the tool bit, inner sleeve  104  and inner and outer nosepieces  112  and  114  can no longer rotate, leaving only outer sleeve  102  to move. Outer sleeve  102  continues to rotate in the tightening direction relative to inner sleeve  104  until it is in the locked position. 
     The locked position is defined by protrusion  150  of sliding lock  148  being situated within locked end  166   b  of lock groove  166 . As outer sleeve  102  moves from the unlocked to the locked position, protrusion  150  and sliding lock  148  moves from unlocked end  166   a  along camming surface  166   c  to locked end  166   b  of lock groove  166 . The movement of sliding lock  148  further to the rear of chuck  100  due to the biasing force of spring  156  causes lock tooth  154  of sliding lock  148  to engage the space between the first and second sides of adjacent teeth of annular array of locking teeth  132  of body  122 . Additionally, as outer sleeve  102  is rotated from the unlocked to the locked position, raised portion  155   a  of detent spring  155  moves to locked detent depression  168   b , and stop  170  of outer sleeve  102  moves from unlocked end  158   a  of flat  158  to locked end  158   b . The engagement of lock tooth  154  of sliding lock  148  and annular array of locking teeth  132  prevents rotation of outer sleeve  102 , inner sleeve  104 , and first and second nosepieces  112  and  114  relative to the body in the clockwise, or opening, direction. Note, however, that continued rotation about the body  122  in the counterclockwise, or tightening, direction, is still possible. More specifically, as the lock tooth  154  rotates in a tightening direction, the lock tooth  154  repeatedly slips over the second side of each tooth  136  of the annular array of locking teeth  132  causing a clicking or ratcheting sound as the locking tooth  107  falls against each subsequent space between adjacent teeth of the annular array of locking teeth  132 . The position of raised portion  155   a  of detent spring  155  within locked end  166   b  of lock groove  166  prevents inadvertent rotation of outer sleeve  102  relative to inner sleeve  104  in the opening direction. As such, chuck  100  will remain locked until a user rotates outer sleeve  102  in the opening direction with enough force to cause raised portion  155   a  of detent spring  155  to move from locked detent depression  168   b  to unlocked detent depression  168   a , as described below. 
     To open chuck  100  from the locked position, a user, when viewing chuck  100  from the rear, turns outer sleeve  102  in a clockwise, or loosening, direction. As outer sleeve  102  begins to rotate, raised portion  155   a  of detent spring  155  is disengaged from locked detent depression  168   b  and stop  170  moves from locked end  158   b  of flat  158  to unlocked end  158   a , at which point raised portion  155   a  of detent spring  155  engages unlocked detent depression  168   a . As outer sleeve  102  rotates relative to inner sleeve  104 , protrusion  150  of sliding lock  148  is urged forwardly from locked end  166   b  of lock groove  166  toward unlocked end  166   a  by camming surface  166   c , thereby causing sliding lock  148  to move forwardly against the spring force of spring  156 . Once lock tooth  154  no longer engages annular array of locking teeth  134 , outer sleeve  102 , inner sleeve  104  and inner and outer nosepieces  112  and  114  start to rotate as a unit about body  122 . As such, jaws  106  are disengaged from the shank of the tool bit, and chuck  100  can be fully opened. 
     These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole and in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention so further described in such appended claims. Therefore, the spirit and scope of the appended claims should not be limited to the description of the preferred versions contained therein.