Abstract:
A drive tool is shiftable between locking and releasing configurations relative to an associated tool, the drive tool including a lock member moveable between a locking position and a release position relative to the associated tool, an actuator member moveable between a locking condition and a releasing condition, and coupling structure interconnecting the actuator member and the lock member. The lock member is tiltable to a latching condition which prevents its movement to its release position. In one embodiment the coupling structure is substantially rigid so that the lock member and the actuator move in substantially the same direction, and in another embodiment the coupling structure is flexible and resilient. The coupling structure may be fixedly coupled to the actuator member or may be loosely coupled thereto and biased to a rest condition.

Description:
RELATED APPLICATION 
     This application claims the benefit of the filing date of copending U.S. provisional application No. 60/318,247, filed Sep. 10, 2001. 
    
    
     BACKGROUND 
     This application relates to hand tools and, in particular, to locking drive tools and devices for releasably locking associated tools. The application relates in particular to improved extension members for socket wrenches and the like, which include a locking mechanism to prevent unwanted separation of a socket or the like from the extension member. 
     Socket wrenches, which may be of the ratcheting or non-ratcheting type, typically include a handle and a head provided with a drive square onto which various sockets may releasably be mounted. In order to be able to use such a wrench to apply torque to fasteners in remote, relatively inaccessible locations, it is known to provide extensions which have a square drive portion at one end and a square socket portion at the other end adapted to fit onto the square drive of the wrench. Retention of a socket on an extension is important because, in use, the socket may be at a distance from the wrench handle and in a relatively inaccessible location, where retrieval could be difficult if the socket becomes disengaged. Accordingly, various arrangements have heretofore been provided for locking a socket in place on an extension. Such prior locking arrangements have had various disadvantages. Some have required that a release mechanism be manually actuated in order to mount a socket on the extension as well as to remove it, some are relatively complex, requiring a relatively large number of parts, some are relatively expensive to manufacture, such as by requiring the drilling of diagonal holes, and virtually all require the conversion of one type of motion to another in transmitting motion from a release actuator to a locking member. 
     SUMMARY 
     The present application discloses a locking drive tool which avoids the disadvantages of prior drive tools, while affording additional structural and operating advantages. 
     In and embodiment, a locking drive tool comprises a body, a lock member carried by the body for movement between a locking position extending from the body and a release position, an actuator member carried by the body for movement between a locking condition projecting from the body and a releasing condition, and coupling structure carried by the body and interconnecting the lock member and the actuator member, the coupling structure being responsive to movement of the actuator member in a predetermined direction from the locking condition to the releasing condition to effect a corresponding movement of the lock member from its locking position to its release position substantially in the predetermined direction. 
     In another embodiment the coupling structure is flexible and resilient and flexes in response to movement of the actuator member to cause movement of the lock member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In an embodiment a locking drive tool is operated between locking and releasing conditions by providing a lock member movable between locking and release positions and an actuator member movable between locking and releasing conditions, and interconnecting the lock member and the actuator member so that movement of the actuator member in a predetermined direction results in a corresponding movement of the lock member substantially in the predetermined direction. 
       In another embodiment, the interconnecting is done through a coupling structure which is flexible and resilient and flexes in response to movement of the actuator member to cause movement of the lock member. 
       For the purpose of facilitating an understanding of the subject matter sought to be protected, there are illustrated in the accompanying drawings embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated. 
         FIG. 1  is a side elevational view of an embodiment of locking extension; 
         FIG. 2  is a bottom plan view of the extension of  FIG. 1 ; 
         FIG. 3  is an enlarged, fragmentary, sectional view taken generally along the line  3 — 3  in  FIG. 1 ; 
         FIG. 4  is an enlarged, fragmentary sectional view taken generally along the line  4 — 4  in  FIG. 2 ; 
         FIG. 5  is a view of the right-hand portion of  FIG. 4  with the locking element illustrated in a latched position; 
         FIG. 6  is a view similar to  FIG. 3 , with the push rod spring removed and with the push rod in a retracted position; 
         FIG. 7  is a side elevational view of another embodiment of extension; 
         FIG. 8  is a bottom plan view of the extension of  FIG. 7 ; 
         FIG. 9  is an enlarged, fragmentary, sectional view taken generally along the line  9 — 9  in  FIG. 7 ; 
         FIG. 10  is an enlarged, fragmentary, sectional view taken generally along the line  10 — 10  in  FIG. 8 ; 
         FIG. 11  is an enlarged perspective view of the release button of the extension of  FIGS. 7-10 ; 
         FIG. 12  is an enlarged perspective view of the lock lever of the extension of  FIGS. 7-10 ; 
         FIG. 13  is a view similar to  FIG. 4  illustrating an alternative embodiment; 
         FIG. 14  is an enlarged, side elevational view of the locking member of the embodiment of  FIG. 13 ; 
         FIG. 15  is a view similar to  FIG. 4  of yet another embodiment; 
         FIG. 16  is an enlarged, side elevational view of the push bar of the embodiment of  FIG. 15 ; 
         FIG. 17  is a side elevational view of the locking member of the embodiment of  FIG. 15 ; 
         FIG. 18  is a front elevational view of a locking member of  FIG. 17 ; and 
         FIG. 19  is a front elevational view of the actuator member of the embodiment of FIG.  15 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1-6 , there is illustrated locking drive tool in the nature of an extension, generally designated by the numeral  10 , having an elongated cylindrical body  11  provided at one end with a square socket recess  12 . The body  11  has a reduced-diameter portion  13  provided at one end with a square drive lug  14  having four flat, planar drive faces  15  in a known manner. Formed in the square drive lug  14  is a cylindrical axial bore  16 , which extends into the length of the reduced-diameter portion  13  a distance which may vary with the length of the extension. The bore  16  has a shallow, slightly enlarged-diameter counterbore  17  (FIG.  3 ), which may be provided at its inner end with an annular undercut groove  18 . Also formed in the reduced-diameter portion  13  is a diametrically extending cross bore  20 , which extends across the axial bore  16  and has an enlarged-diameter counterbore  21  which may be encircled at its outer end by a recess  22 , which may be beveled (See FIG.  4 ). Also formed in one face of the square drive lug  14  parallel to the cross bore  20  is a cross bore  25  which intersects the axial bore  16 . Another shallow circular bore  26  is formed in the same face  15 , eccentric with respect to the cross bore  25 , and cooperates with the cross bore  25  to define a shoulder  27  which forms a latch surface. 
     Disposed in the axial bore  16  is coupling structure including an elongated pushbar  30  which is bifurcated at its rear end to define a pair of clevis legs  31  separated by an elongated slot  32 . Each of the legs  31  is provided at its distal end with a laterally outwardly and downwardly projecting tang  33 . The front end of the pushbar  30  is also bifurcated to form a pair of short clevis legs  35  separated by a slot  36 . Recesses  37  are formed, respectively, in the upper and lower surfaces of the pushbar  30  just rearwardly of the front legs  35 . Seated in the blind end of the axial bore  16  is a helical compression spring  38  which bears against the distal ends of the rear legs  31  for urging the pushbar  30  forwardly (to the right, as viewed in the drawings). 
     An actuator member in the nature of a release button  40  has an enlarged cylindrical head  41  and a reduced-diameter cylindrical shank  42  provided with parallel flats  43  ( FIG. 6 ) along opposite sides thereof. Formed in the distal end face  44  of the shank  42  is an annular recess defining a shoulder  45 . A helical compression spring  46  is seated in the blind end of the bore  20 . Flats  47  are formed on the cylindrical head  41  of the release button  40 , respectively parallel to the flats  43 . The release button  40  is inserted in the counterbore  21 , with the upper end of the spring  46  seated against the annular shoulder  45 , as can best be seen in FIG.  4 . 
     The extension  10  also includes a lock member in the form of a cylindrical lock button  50  provided with parallel flats  51  ( FIG. 3 ) along opposite sides thereof and having a rectangular notch  52  formed in the rear thereof and extending between the flats  51 . The upper end of the lock button  50  is sloped to define a cam surface  53 . Just below the forward end of the cam surface  53 , the lock button  50  is undercut, as at  54 , to define a latch surface or lip  55  (see FIGS.  4  and  5 ). 
     In assembly, the spring  38  is inserted in the axial bore  16  and seated at its inner end, and the spring  46  is inserted through the counterbore  21  and seated at the inner end of the bore  20 . Then the release button  40  is inserted in the counterbore  21  and seated on the spring  46  and rotated so that its flats  43  are aligned parallel to the longitudinal axis of the extension  10 . In this regard, the flats  47  on the head  41  will assist in assembly by providing an indication as to when the flats  43  are properly aligned. Then the pushbar  30  is inserted in the axial bore  16 , legs  31  first, the release button  40  being depressed sufficiently to permit the legs  31  to straddle the shank  42  for engagement with the flats  43 . Upon release of the release button  40  it is urged upwardly by the spring  46 , the portion of the shank  42  beneath the flats  43  engaging the undersides of the legs  31  to urge the pushbar  30  upwardly against the upper side of the axial bore  16 . For ease in assembly, the release button  40  could be preassembled with the spring  44 , by locking one end of the spring  44  against the shoulder  45 . 
     Then, using a suitable tool engaged with clevis legs  35 , the pushbar  30  is depressed against the urging of the compression spring  38  a sufficient distance (see  FIG. 6 ) to permit insertion of the lock button  50  in the cross bore  25 . Then the pushbar  30  is released and the spring  38  returns it to its original position, to allow the closed end of the slot  36  to overlap the notch  52  of the lock button  50  without loading it, and to allow the sides of the slot  36  to engage the flats  51 . The spring  46  serves to hold the lock button  50  in an extended position, illustrated in  FIGS. 1 and 4 , projecting a slight distance outwardly beyond the associated face  15  for engagement with an associated tool, such as a socket or the like (not shown). Then the outer end of the axial bore  16  is closed by inserting an expansion plug  57  into the counterbore  17  and applying compression force to the expansion plug to collapse it into the groove  18 . Alternatively, the groove  18  may be omitted and the outer edge of the counterbore may be upset to hold the plug  57  in place after its insertion. 
     In operation, when a coupling tool such as a socket is inserted on the square drive lug  14 , it will engage the cam surface  53  of the lock button  50 , camming it and the pushbar  30  downwardly to a retracted position (not shown), against the urging of the spring  46 , to permit movement of the socket past the lock button  50  until the detent recess of the socket moves into alignment with the cross bore  25 , permitting the lock button  50  to return to its extended position illustrated in FIG.  4  and engage in the detent recess of the socket. 
     When it is desired to remove the socket, the release button  40  is depressed against the urging of the spring  46 , depressing the pushbar  30  and, thereby, retracting the lock button  50  to permit removal of the socket. It is a significant aspect that the associated socket, once mounted on the extension  10 , cannot be pulled off without depressing the release button  40 . Any attempt to do so will cause the detent recess of the socket to engage the rear end of the projecting portion of the lock button  50 , causing it to freely tilt forwardly, as illustrated in  FIG. 5 , this tilting being accommodated by the recessed surfaces  37  on the pushbar  30 . This tilting will bring the lip  55  on the lock button  50  into engagement with the shoulder  27 , preventing retraction of the lock button  50 . It will be appreciated that the cooperation of the flats  51  on the lock button  50  with the legs  35  of the pushbar  30  prevent rotation of the lock button  50  out of its proper orientation. 
     When the release button  40  is depressed, pushing the pushbar  30  downwardly, the tangs  33  on the pushbar  30  legs will engage the bottom of the axial bore  16  first. Continued depression of the release button  40  will cause the pushbar  30  to pivot slightly about the tangs  33  as a fulcrum, providing increased leverage to retract the lock button  50 . The fact that the pushbar  30  is held against the top of the axial bore  16  by the spring  46  maximizes the travel of the release button  40 . This amount of travel would be important for power tool sockets which have a detent hole in their side wall instead of detent recess. In such applications the lock button  50  would be longer to project further from the extension and would not require the engagement of the lip  55  with the locking shoulder  27 , since the straight transverse detent hole of the socket, which is perpendicular to the longitudinal axis, would engage the projecting rear end of the lock button  50  and place it in shear, so that no retraction of the button would be possible. The spring  46 , in addition to maximizing travel for the release button  40 , keeps the parts under preload with minimum downward motion of the pushbar  30  when an attempt is made to remove a socket from the extension  10 , and prevents parts from rattling. 
     Significantly, the portion of the pushbar  30  between the release button  40  and the lock button  50  is substantially rigid, having sufficient stiffness that when the release button  40  is depressed it, along with the pushbar  30  and the lock button  50 , are all moved in substantially the same direction, transversely of the longitudinal axis of the extension  10 , so that there is no motion direction-changing mechanism between the release button  40  and the lock button  50 . 
     Referring now to  FIGS. 7-12 , there is illustrated an alternative embodiment of extension, generally designated  60 , which has an elongated cylindrical body  61  provided at one end with a square socket recess  62 . The body  61  has a reduced-diameter portion  63  provided at its distal end with a square drive lug  64  having with four flat planar faces  65 . Formed in the distal end of the square drive lug  64  is a cylindrical axial bore  66 , which projects a predetermined distance into the length of the reduced-diameter portion  63 . The bore  66  is provided with a shallow counterbore  67  having at its inner end an annular undercut groove  68 . Formed transversely in the reduced-diameter portion  63  is a cross bore  70  which extends across the axial bore  66  and is provided with an enlarged-diameter counterbore  71 , the outer end of which is surrounded by a recess  72 , which may be beveled. Formed in one face  65  of the square drive lug  64  and communicating with the axial bore  66  is a cross bore  75  which is generally oblong in transverse cross-sectional shape, and has a longitudinal axis which extends in a direction substantially perpendicular to that of the cross bore  70 . Extending through opposed faces  65  of the square drive lug  64  is a cylindrical bore  76  which intersects the axial bore  66  and has a longitudinal axis substantially parallel to that of the cross bore  70 . 
     Disposed in the axial bore  66  is coupling structure including an elongated toggle beam  80  which is a substantially flat member bifurcated at one end to define a pair of clevis legs  81 , the distal ends  82  of which are downturned, as can best be seen in  FIG. 10 , the legs  81  being separated by a slot  83 . A side cutout  84  is formed in the front end of the toggle beam  80  to define a seat shoulder  85 . The toggle beam  80  may also be provided with a transverse notch  86  adjacent to the forward end of the cutout  84 . 
     The extension  60  includes an actuator member in the form of a release button  90  which has an enlarged cylindrical head  91  dimensioned to slidably fit in the counterbore  71 , and is provided intermediate its length with an annular groove  92  which defines a reduced-diameter shank  93  dimensioned to fit in the slot  83  of the toggle beam  80 . The groove  92  defines a shoulder  94  on the head  91 . The portion of the release button  90  below the groove  92  is cut away to define parallel flats  95 , spaced apart a distance substantially equal to the diameter of the reduced-diameter shank  93 . The upper end of this portion may be chamfered, as at  95   a . Formed at the distal end of the button  90  are recesses  96  which define a seat for one end of the helical compression spring  97 , the other end of which is seated in the closed end of the cross bore  70 . 
     The extension  60  also includes a lock member in the form of a cylindrical lock lever  100  which is generally oval or oblong in transverse cross-sectional shape and is provided with a bore  101  extending transversely therethrough for receiving a pivot pin  102 , the ends of which are respectively seated in opposite ends of the bore  76  in the square drive lug  64 . One end of the lock lever  100  is bifurcated by a slot  103  ( FIG. 12 ) to define a pair of legs  104 , the lock lever  100  having shallow recesses on opposite ends of the slot  103  to define a tang  105 . The opposite end of the lock lever  100  is sloped to define a cam surface  106 . Disposed in the side cutout  84  of the toggle beam  80  is a helical compression spring  107 , one of which is seated against the seat shoulder  85  and the other end of which bears against the rear side of the lock lever  100 . 
     In assembly, the spring  97  is first seated in the cross bore  70  and then the release button  90  is inserted in the counterbore  71  and seated against the spring  97  so that the flats  95  on the release button  90  are aligned parallel to the longitudinal axis of the extension  60 . Then the toggle beam  80  is inserted in the axial bore  66 , legs first, so that the legs straddle the flats  95  of the release button  90  and come to rest at the inner end of the axial bore  66 . The release button  90 , which has its shank  93  aligned with the slot  83  of the toggle beam  80 , is then rotated 90° to latch the legs  81  in the annular groove  92  of the release button  90 , this rotation being facilitated by the chamfers  95   a . The spring  107  may be inserted in the axial bore  66  until it engages the seat shoulder  85 , then the lock lever  100  is inserted in the cross bore  75  in engagement with the forward end of the spring  107  for biasing the toggle beam  80  against the inner end of the axial bore  66 , with the legs  104  of the lock lever  100  straddling the forward end of the toggle beam  80  and the tang  105  seated in the slot  86 . Then the lock lever  100  is pinned in place by extending the pivot pin  102  through the aligned bores  76  and  101  so that the lock lever  100  is pivotally movable about the axis of the pivot pin  102 . After assembly, the axial bore  66  is closed by insertion of an expansion plug  108  into the undercut groove  68 , in the same manner as was described above in connection with the extension  10 . 
     Once assembled, the spring  107  will urge the lock lever  100  and the engaged toggle beam  80  forwardly, so that the lock lever  100  bears against the forward end of the cross bore  75 , as seen in  FIG. 9 , and projects outwardly from the cross bore  75  a predetermined distance beyond the associated face  65  of the square drive lug  64 . 
     When an associated socket (not shown) is pushed onto the square drive lug  64 , it engages the cam surface  106  of the lock lever  100  pivoting it rearwardly (counterclockwise as shown in  FIG. 9 ) about the axis of the pivot pin  102  and against the urging of the spring  107 , thereby retracting the lock lever  100  and permitting the associated socket to pass. As the lock lever  100  pivots rearwardly, it partially compresses the spring  107  and also, by action of the tang  105 , pulls the toggle beam  80  forwardly, compressing the spring  107  from the rear. When the detent recess in the associated socket passes over the cross bore  75 , the lock lever  100  pivots back up under the urging of the spring  107  to its original position, and seats in the detent recess of the socket, thereby locking the socket in place. The socket cannot be pulled off, because the lock lever  100  is seated against the forward end of the cross bore  75 , and the toggle beam  80  is seated against the inner end of the axial bore  66  (see FIG.  10 ). The cutout  84  and spring  107  could be inclined to the axis of the bore  66  so that a larger component of force would be exerted axially of the spring  107  when the lock lever  100  is pivoted. 
     In order to remove the socket, the release button  90  is depressed, deforming the legs  81  of the toggle beam  80 , tending to straighten them, and thereby moving the forward end of the toggle beam  80  forwardly against the lock lever tang  105 , pivoting it counterclockwise (as viewed in  FIG. 9 ) to a retracted position to permit removal of the socket. The forward movement of the toggle beam  80  and the tilting of the lock lever  100  compress the spring  107 , as explained above, so that, when the socket is removed and the release button  90  is released, the spring  107  returns the toggle beam  80  and the lock lever  100  to their original positions. 
     An associated socket cannot be removed without depressing the release button  90 . An attempt to do so will cause the detent recess to engage the vertical rear face of the lock lever  100 , which cannot tilt clockwise because it is engaged with the front end of the cross bore  75 . 
     Referring to  FIGS. 13 and 14 , there is illustrated a locking extension  110 , which is substantially the same as the locking extension  10 , described above, except as hereinafter explained. The locking extension  110  includes a pushbar  130  similar to the pushbar  30 , described above, except that it is provided at its forward end with a pair of clevis legs  135 , which slope slightly downwardly and forwardly at a small angle. Thus, the legs  135  having sloping upper surface  137  and sloping lower surface  139 , such that the forward ends of the surfaces  137  and  139  converge slightly forwardly, while the rearward ends thereof converge slightly rearwardly, so that the thickest points of the legs  135  are substantially midway along their lengths. 
     The locking extension  110  also includes a lock button  150  which has a generally cylindrical body  151  having a longitudinal axis  152  (FIG.  13 ). Projecting upwardly from the cylindrical body  151  is a head  153 , the body  151  being undercut beneath the head  153  to define a forwardly projecting lip  155  disposed for engagement with the latch surface  27 . The forward end of the head  153  defines a cam surface  156  rear end of the head  153  defining a contoured engagement surface  157 . Formed in the rear end of the body  151  adjacent to the inner end thereof generally U-shaped notch  158  which defines substantially parallel flats  159  (one shown) respectively at diametrically opposed sides of the body  151 . 
     In operation, the extension  110  performs substantially like the extension  10 , described above, except that it is designed to lock more effectively those sockets with an internal detent recess rather than a power socket with a detent hole through its side wall. As is illustrated in  FIG. 13 , the upper surfaces of the notch  158  rest on the upper surfaces  137  of the legs  135  of the pushbar  130  at the rearward portions thereof, so that the axis “x”  152  of the lock button  150  is inclined slightly with respect to the axis of the cross bore  25 . If one attempts to remove an associated socket from the extension  110  by simply pulling it forwardly, the lock button  150  will not have to pivot as far to engage the lip  155  with the shoulder  27  as with the extension  10 , thus giving a tighter overall feel to the locking attachment of the associated socket. It will be appreciated that the rearwardly converging rear portions of the clevis leg upper and lower surfaces  137  and  139  provide for clearance the body  151  at the lower rear end of the notch  158  to facilitate the tilting movement of the lock button  150 . 
     Now it is significant that when the contoured engagements surface  157  is in contact with the detent of a socket (not shown) during and attempt to remove the socket from the extension  110 , the force vector normal to the surface  157  at the point of contact, along the line cap A in  FIG. 13  intersects the shoulder  27 , resulting in a positive engagement of the lip  155  with the shoulder  27 . This is an improvement over the arrangement illustrated in  FIG. 5 , above, wherein the force vector normal to the curved surface at the rear of the lock button  50  at the point of engagement with a socket detent may lie along the line cap B which passes rearwardly of the shoulder  27 . This tends to exert a counterclockwise rotational force on the lips  55  at its point of contact with the shoulder  27  which might tend to pivot it off the shoulder. 
     Referring now to  FIGS. 15-19 , there is illustrated an extension  210 , which is similar to the extension  110 , except as explained hereinafter. The extension  210  has an elongated body  211  having an axial bore  216  formed in the end of the square drive lug, which has a depth slightly less than that of the axial bore  16 , described above. Formed in the body  211  is a cross bore  220 , which extends diametrically across the axial bore  216  adjacent to its inner end. Also formed in one face of the square drive lug parallel to the cross bore  220  is a cross bore  225 , which intersects the axial bore  216 . 
     Disposed in the axial bore  216  is coupling structure including an elongated pushbar  230  which has a substantially cylindrical main body  231 , the forward end of which defines a turned portion  232  having a longitudinally central region  233  with a diameter substantially the same as that of the remainder of the main body  231 . The turned portion  232  (See  FIG. 16 ) also has a substantially frustoconical rear portion  234 , which tapers rearwardly from the central region  233 , and a frustoconical front portion  235 , which tapers forwardly from the central region  233 . The forward end of the frustoconical front portion  235  is continuous with a reduced diameter tip  236  The rear end of the main body  231  is chamfered, as at  237 . 
     An actuator member in the nature of a release button  240  has a substantially cylindrical body  241  dimensioned to be slidably received in the cross bore  220 . The body  241  has an inner end face  244  ( FIG. 17 ) in which is formed an annular recess defining a shoulder  245 . Extending axially through the body  241  adjacent to the shoulder  245  is a circularly cylindrical bore  246 . 
     The extension  210  also includes a lock member in the form of a substantially cylindrical lock button  250 , which is similar to the lock button  150 , described above, except as hereinafter explained. The lock button  250  has a substantially cylindrical body  251 , the inner end of which may be beveled at the rear side thereof, as at  252  (FIG.  18 ). Extending through the body  250 , so as to intersect both the beveled rear end  252  and the undercut  254 , is a circularly cylindrical bore  258  having a diameter slightly greater than that of the cylindrical body  231  of the pushbar  230 . 
     In assembly, the release button spring  46  is first inserted in the bottom of the cross board  220 , after which the release button  240  is inserted therein and seated on the spring  46 . In this regard, the parts are so dimensioned that the release button  240  slidably fits in the cross bore  220 . Then the lock button  250  is inserted in the cross bore  225 . Then the pushbar  230  is inserted into the axial bore  216  from the front end thereof, the rear end of the pushbar  30  being passed through the bore  258  of the lock button  250  and into the bore  246  of the release button  240 , the parts being dimensioned so as to provide a light press fit of the pushbar  230  in the release button bore  246 . To assist in assembly, an assembly tool (not shown) may be dimensioned to receive the tip  236  of the pushbar  230  therein, the tool being dimensioned to bottom against the end face of the square drive lug  14  when the proper depth of insertion of the pushbar  230  is achieved, thereby assuring that the turned portion  232  of the pushbar  230  will be properly positioned in the lock button bore  258  to afford proper tipping action of the lock button  250 . Then the assembly tool may be removed and the expansion plug  57  is installed to close the axial bore  216 . 
     The operation of the extension  210  would be substantially like that of the extension  110 , described above. However, in this case the pushbar  230  is held in position longitudinally by the press fit in the release button bore  246  and the close fit of the release button  240  in the cross bore  220 , thereby permitting elimination of the bias spring  38  of the pushbar  30 , which also permits elimination of the tipping tangs  33 . The frustoconical rear and front portions  234  and  235  on the pushbar  230  accommodate the tilting of the lock button  250 . 
     The extension  210  affords the advantage of reduced cost, the cost saving resulting from the reduced depth of the axial bore  216 , the elimination of the pushbar spring  38 , and having the pushbar  230  formed by a turning machine rather than injection molding, metal injection or die casting. Also, the pushbar  230  does not have to be rotationally oriented in any particular way to cooperate with the other parts. The increased depth of the cross bore  225  provides clearance to permit a greater travel of the lock button  250  toward its release position. An alternative arrangement could provide a release button with a hollowed-out inner end to receive the spring  46 , thereby permitting the maximum diameter of the release button body  241  to extend all the way across the axial bore  216 , affording a longer sliding fit between the release button  240  and the cross bore  220 , thereby better retaining the release button  240  against tipping, so as better to hold the pushbar  30  parallel to the longitudinal axis of the axial bore  216 . 
     While the foregoing description is in the context of a locking extension, it will be appreciated that the principles described above could be applicable to other types of locking drive tools, such as socket wrenches, hand drives, breaker bars, universals, adapters and the like, which are adapted to have an associated socket or similar tool releasably mounted thereon. 
     From the foregoing, it can be seen that there has been provided an improved extension which permits an associated socket to be mounted by simply being pushed on and then being automatically locked in place, removal being prevented except by manual depression of an associated release button. The extension is of relatively simple and economical construction and, in the preferred embodiment, is characterized by ease of assembly. 
     The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of applicants&#39; contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art.