EP0433284B1

EP0433284B1 - Locking socket wrench drive device

Info

Publication number: EP0433284B1
Application number: EP88909489A
Authority: EP
Inventors: Michael Nickipuck
Original assignee: Qualicorp Ltd
Current assignee: Qualicorp Ltd
Priority date: 1988-09-06
Filing date: 1988-09-06
Publication date: 1995-06-14
Anticipated expiration: 2008-09-06
Also published as: AU650231B2; DE3854001T2; EP0433284A4; DE3854001D1; CA1325739C; EP0433284A1; AU2618688A

Abstract

A socket wrench drive extension (9) incorporates a quick release and locking feature. The extension (9) is used in conjunction with a ratchet drive and standard mechanics sockets for driving threaded fasteners. The extension uses a longitudinal control bar (14) which bears directly or indirectly on a detent (22, 24, 37, 38) contained in a transverse bore (19) at the driving end of the extension. The control bar (14) fits in a channel (10) on the exterior and is operated through the retraction of a spring loaded collar (15).

Description

Socket wrenches incorporating ratchet drives and standard sockets for driving threaded fasteners including most commonly hexagonal nuts and bolt heads are commonly used in the mechanic's field. In situations where a mechanic is confronted with the requirement for driving a fastener located in a tight space restricting the swing of the drive ratchet handle, extension drives are utilized to transmit the force from the ratchet to the socket. When driving a fastener in a remote location and particularly in a situation where the work must he accomplished in close quarters and with obstructions present, it is desirable to have a mechanism by which the socket can be locked to the extension. In addition to the desirability of a locking feature, it is necessary to provide for the rapid changing of sockets for driving various sizes of fasteners. In the environment in which a mechanic works, for example, in repairing vehicles or machinery, the mechanic often encounters an adverse environment involving temperature variations, corroded or damaged fasteners, time pressures regarding the completion of jobs as well as oily and greasy conditions rendering a positive locking and releasing feature desirable. Under these situations, it is desirable for any mechanism to be simple and reliable as well as durable while proving an effective means of improving the efficiency of the work. Another requirement for mechanic's tools is that they be relatively simple to manufacture and maintain.
Various methods are known by which fastener drive sockets can he affixed to mechanisms with which to drive those sockets. Most systems involve methods tailored to specific needs providing positive locking mechanisms for tools such as impact wrenches, where it is important to have the sockets firmly attached to the drive. In these applications complicated machining may be utilized since the drive mechanisms are of a relatively large size and bulk providing adequate strength despite extensive internal machining. In addition, these mechanisms are all devised to be utilized in a location where the operator is provided ample work space and compactness of the mechanism is not an important factor. Known mechanisms incorporate locking means such as external rotating collars which are unsuitable release from friction with obstructions (US-A-2,162,353). Other mechanisms involve plungers as locking mechanisms which must be released utilizing a separate (US-A-2,954,934; US-A-2,987,334). Other locking mechanisms involve the use of set screws, pins or other awkward releasing mechanisms requiring the removal of the socket from the fastener or workpiece and preventing rapid release of the sockets in work in close quarters (US-A-2,677,562).
One other type of mechanism known in an application similar to that for the instant invention is a push button release for a ratchet socket drive. This mechanism is unlike the invention in that it requires relatively complicated machining, is relatively difficult to maintain and subject to malfunction from dirt or wear, and is unsuitable for use on extensions because of the utilization of a central axial bore and pushbutton. Finally, this type of mechanism involves application of both a downward pressure on a pushbutton plunger while requiring the resistance against which this force is applied as well as the simultaneous movement of the socket in the same direction as the pushbutton and in the direction opposite the resistance, which is an awkward motion for a mechanic in tight spaces. The pushbutton ratchet release also requires that the mechanism be machined out of larger pieces for the same strength as non-machined parts, rendering it frequently difficult to utilize the ratchet and socket combination alone in tight spaces (US-A-3,762,245).
It is known from US-A-4,480,511 to provide a socket wrench drive extension comprising:
an elongate main shank including a first shank portion at the rear end for receiving rotative motion and a second shank portion at the forward end for transmitting the rotative motion to a releasably connected socket member,
a movable control bar arranged in an axially extending channel in the shank and slidably moveable between a forward locking position and a rearward release position by means of a movable sleeve arranged about the main shank, said control bar being urged towards the forward locking position by a spring acting on the sleeve,
a transverse aperture connecting the bottom of the channel radially inwardly of the control bar with the diametrically opposite side of the first shank portion and accommodating locking means in the form of two retainer balls, said balls and said aperture being so dimensioned that the balls at all times project from the ends of the aperture,
wherein the control bar includes a radially outwardly directed surface adapted to engage an inner wall of the socket member and a radially inwardly directed surface adapted to engage the adjacent retainer ball and via said engagement move the other retainer ball towards a diametrically opposite inner wall of the socket member thereby effecting locking engagement between said socket member and the wrench drive extension.
Viewed from a first aspect, the present invention is characterised in that the radially inwardly directed surface of the control bar includes a forward bevelled section adjacent the locking means and a rear section with a notch and a radially inwardly projecting latch element, the bevelled section having such an axial extent that it contacts the adjacent retainer ball both in the locking and the release position of the control bar,
the bottom of the channel includes a recess near its rear end and adjacent said latch element of the control bar, and a spring is interposed between the retainer balls to urge these apart thereby simultaneously exerting a radially outwardly directed force on the bevelled section of the control bar to impart thereto a tilting tendency, so that when the latch element of the control bar engages the recess of the channel the control bar undergoes a limited tilting movement, thereby latching the control bar in the release position.
Viewed from another aspect, the present invention is characterised in that the radially inwardly directed surface of the control bar includes a forward bevelled section adjacent the locking means the bevelled section having such an axial extent that it contacts the adjacent retainer ball both in the locking and the release position of the control bar,
a spring is interposed between the retainer balls to urge these apart thereby simultaneously exerting a radially outwardly directed force on the bevelled section of the control bar to impart thereto a tilting tendency, and
the radially outwardly directed forward end of the control bar has a forwardly open recess comprising a first surface substantially parallel to the axis of the control bar and a second surface perpendicular to the first surface and forming a rear end shoulder of the recess, wherein the second shoulder surface is adapted to engage the end surface of the socket member when the wrench extension is inserted into said socket thereby sliding the control bar rearwardly towards the release position.
An additional embodiment utilizes the device herein described with modifications so as to provide for a locking and release action at both the driven end of a socket wrench drive shank and the driving end. In this embodiment, the sliding collar has been rearwardly extended and is of a dimension sufficient to be slidably carried relative to the outside diameter of the driven portion of the placement of a fixedly mounted pin in the surface of the shank, said pin intersecting a generally L-shaped slot permits limited forward and rearward travel and limited rotational travel.
At least in a preferred embodiment, a socket wrench drive extension is designed for use in conjunction with a ratchet drive handle and standard sockets for driving threaded fasteners. The extension incorporates a longitudinal control bar channel machined in one phase of the square drive portion of the socket and extending past the shoulder separating the driven portion from the extension portion of the device. A control bar is incorporated which is slidably mounted within the machined control bar channel, moving longitudinally therein. The lower end of the control bar is machined in this embodiment to an angle of approximately 15-30° bevelled to the lips.
The further modification of the sleeve to encompass this embodiment includes the placement of one or more grooves or recesses in the inner surface of the sleeve in the section where it rearwardly extends over the surface of the driven end of the shank. These recesses permit the retraction of a retainer ball placed in said driven end. The recesses are so oriented such that the rotation and rearward movement of the sleeve results in the exertion of inward pressure on the driven end retainer ball or balls. When one driven end retainer ball is oriented so as to compress the customary retainer ball on the driving end of a ratchet wrench or other equivalent driving tool, the shank of the extension is fixedly mounted with respect thereto.
Through the use of this embodiment, the device can function as an adaptor, rather than a mere quick release provision on the end of an extension of a fixed length. In this way the quick release and locking features may be utilized in complete compatibility with a mechanic's existing set of driving tools, particularly with extensions of varied lengths. A further advantage is that the driven end locking feature provides a positive locking action thus avoiding unwanted release of the device itself or the tools attached to the driving end of the device.
Certain socket wrench drive extensions and some preferred embodiments of the present invention will now be described by way of example only and with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view of a socket wrench drive extension and a standard socket of the prior art in the release position.
Fig. 2 is a perspective view of the arrangement shown in Fig. 1 in the locked position.
Fig. 3 is a fragmentary sectional view of the extension shown in Fig. 1 in its released position.
Fig. 4 is a fragmentary sectional view of the arrangement shown in Fig. 1 in its locked position.
Fig. 5 is an exploded perspective view of the extension shown in Fig. 1 showing its parts in relation to each other.
Fig. 6 is a perspective view of an extension of the prior art as adapted to a power socket wrench drive device through the use of a yoke and bearing.
Fig. 7 is a fragmentary sectional view of an extension of the prior art utilizing a retainer ball and single bearing ball.
Fig. 8 is a fragmentary sectional view of an extension of the prior art utilizing a multiplicity of ball bearings as a force transmittal device.
Fig. 9 is a fragmentary sectional view of another extension of the prior art utilizing a single retention member of generally cylindrical configuration.
Fig. 10 is a perspective view of a socket wrench drive extension with a double locking configuration in the locked position.
Fig. 11 is a sectional view of the extension of Fig. 10 in the released position.
Fig. 12 is a sectional view of the extension of Fig. 10 in the locked position.
Fig. 13 is an exploded view of the extension of Fig. 10, further demonstrating the method of assembly and disassembly.
Fig. 14 is an enlarged sectional view of an alternative driving portion.
Fig. 14a is a perspective cut away view of another socket wrench drive extension.
Fig. 15 is a sectional view of the driving portion of the extension shown in Fig. 14a in the locked position.
Fig. 16 is a sectional view of the driving portion of the extension shown in Fig. 14a in its released position.
Fig. 17 is an enlargement of the driving portion of the extension shown in Fig. 15.
Fig. 18 is an enlargement of the driving portion of the extension shown in Fig. 16.
Fig. 19 is a sectional view of a driving portion of another extension in its locked position.
Fig. 20 is a sectional view of the driving portion of the extension shown in Fig. 19 in its unlocked position.
Fig. 21 is a sectional view of the driving portion of a preferred socket wrench drive extension in accordance with a first aspect of the present invention in its locked position.
Fig. 22 is a sectional view of the driving portion of the preferred embodiment shown in Fig. 21 in its unlocked position.
Fig. 23 is a sectional view of an extension in which a separate securement structure is attached to a drive shank.
Fig. 24 is a sectional view of an alternative securement structure attached to a drive shank.
Fig. 25 is a sectional view of the driving portion of a preferred socket wrench drive extension in accordance with a second aspect of the present invention in its locked position.
Fig. 26 is a sectional view of the driving portion of the preferred embodiment of Fig. 25 in its locked position.

The socket wrench drive extensions shown in Figures 1 to 9 are known from US-A-4,480,511 and are not embodiments of the present invention. Preferred embodiments of the present invention are shown in Figures 21, 22, 25 and 26. The remaining socket wrench drive extensions shown in Figures 10 to 20, 23 and 24 contain features which can be applied to preferred embodiments of the present invention.
In Fig. 1 there is illustrated a socket wrench drive extension of the prior art having a driven portion 11, a shank 9, and a driving portion 12. The socket wrench drive extension is designed to be driven by the square drive portion of a standard ratchet handle mating with the driven portion 11. The driving portion 12 of the socket wrench drive extension mates with and drives a standard socket 21.
Machined in the surface of the shank 9 is a control bar channel 10 which extends along a substantial portion of the shank 9 through the shoulder 27 between the shank 9, which is cylindrical in cross-section, and the driving portion 12, which is square in cross-section. A control bar 14 includes an outer positive locking and centering portion 13 at its lower end. The sleeve engagement spur 16 is an integral part of the control bar 14 which is located equidistant from the ends and serves to engage the control bar with the sleeve 15.
The sleeve 15 includes internally machined control bar engagement spurs 28 which transmit motion from the sleeve 15 to control bar 14.
Internal of the sleeve is a helical spring 17 which bears on the upper portion of the control bar engagement means 28 at the lower end of the spring 17 while being retained by a C-clip 18 fitting a groove 30 machined in the circumference of the drive extension shank 9.
The helical spring 17 is shown in its compressed position in Fig. 1 as the sleeve 15 is pulled axially toward the driven end of the extension shaft 11 and away from the driving end of the extension shaft 12 through a force exerted directionally upward by the user against the grippable portion 29 machined into the exterior of the sleeve. The rearward displacement of the sleeve and connected control bar accomplished the operation as demonstrated in greater detail in Fig. 3 and 4. The control bar bevel 25 then releases the ball detent mechanism thereby releasing the standard fastener driving socket 21.
Fig. 2 is a perspective view which shows the prior art arrangement in position for use with the sleeve 15 released by the user and forced downward by the spring 17. As the sleeve 15 is forced downward it in turn forces the control bar 14 downward through the engagement spurs 16 and 28 which displaces the locking mechanism outward and retains the socket 21 in a locked position. The maximum extension of the control mechanism including the sleeve 15, spring 17 and control bar sleeve engagement spur 16 is restricted by a C-clip or circlip fitted in a circumferential groove 30 machined in the shank 9 of the extension drive shaft. In Figs. 10-13, improvements to the prior art arrangements such as other fastening means being substituted for C-clips are suggested.
Fig. 3 is a fragmentary cross-sectional view of a prior art drive extension showing the lower portion of the drive extension shank 9, the square driving portion of the socket wrench drive extension shaft 12. The entire control mechanism, the engagement spurs 16 and 28 located on the control bar and sleeve respectively, control bar 14, spring 17, and C-clips 18 are shown in this sectional view.
Also shown in Fig. 3 is the lower locking portion of the control bar 14 which comprises the outer positive locking and centering portion of the control bar 13, as well as the bevelled release surface 25 of the control bar 14. Apparent in this sectional view is the transverse bore 19 positioned in such a way as to intersect the control bar channel 10. This transverse bore 19 is knurled or otherwise machined at either end to decrease the diameter of the bore so as to retain the locking ball bearing 24, and the transmission shaft 23 through which a locking force can be transmitted to the retainer ball 22.
Fig. 3 shows the arrangement of Fig. 1 in the spring-compressed position, which permits the retainer mechanisms ball bearing 22 and 24, and force transmission shaft 23 free to be displaced radially through the transverse bore toward the control bar channel the permitting the removal of the socket.
As can be seen in Fig. 3 the C-clips 18 further serve to provide radial pressure against the outer surface of the control bar 14 to prevent its displacement outward, as does the inner wall of the sleeve 15.
Fig. 4 is fragmentary sectional view showing the features as described in Fig. 3 as well as the drive socket 21 which includes a recess 26 against which the retainer ball bearing 22 is forced through operation of the control bar.
Fig. 4 shows the spring 17 in its extended configuration forcing the sleeve 15 downward through operation of the engagement spurs 28 and 16 to its maximum extension as restricted by the C-clips 18. Through the operation of the engagement spurs 28 and 16 the control bar 14 is also extended downward to its maximum operating extension point. Through the range of motion the control bar downward bevelled release surface 25 of the control bar applies constant force across the ball bearings 24 which through the force transmission shaft 23 extends the retainer ball 22 progressively farther outward on the opposite face the square socket drive portion 12. It is important to have the angle of the bevelled surface 25 and the narrowest portion of proper dimensions so as to displace the locking mechanism far enough to permit the locking of standard sockets by using a dimension appropriate given the standard dimension of the socket locking depression 26.
As downward or forward most extension of the control bar 14 occurs and outward most displacement of the locking mechanism 24, 23 and 22 occurs, the flat interface of the control bar 14 prevents further transverse movement of the locking mechanism 22, 23 and 24 by virtue of the fact that the force is acting approximately 90 degrees in relationship to the locking surface of the control bar 14.
In the locked position the outer positive locking and centering portion 13 of the control bar 14 is in contact with the inner drive wall 31 of the square drive on the standard socket 21. Because of the positive locking nature of the locking mechanism any downward force on the socket while in the locked position is distributed evenly through the retainer ball 22, force transmittal shaft 23 and locking ball bearing 24 through the positive locking and centering portion 13 of the control bar 14 to provide even forces on opposite inner walls 31 of the square drive of a standard socket which serves to center the socket so that as rotational forces act on the entire mechanism through the socket wrench drive extension shaft these forces are distributed approximately equally on or near each corner of the walls of the driving portion 12 of the socket wrench drive extension shaft and the driven inner walls 31 of the standard socket wrench 21. The centering action is desirable in general to transmit equal rotational forces and in particular in cases where the driven inner walls of the standard sockets suffer from wear and or being oversized.
Fig. 5 is a perspective exploded view of a prior art drive extension showing the parts separately in relation to each other.
Fig. 6 is a perspective view of an alternative extension known to the art in which the sleeve 15 is non-rotatably mounted relative to the drive shaft of a power driven socket wrench 32. In this arrangement the sleeve itself is mounted in a rotating bearing 33 through which the downward or rearward force is transmitted through a mechanism 35 pivotally mounted on the casing of the power driven socket wrench, which mechanism utilizes a semi-circular yoke 36 around the drive shaft and sleeve. The exertion of force on the release lever 34 is transmitted through the bearing to the sleeve, which in turn transmits the force through a mechanism as described in Figs. 1-5, which provides a ready and quick means of releasing said sockets.
Fig. 7 is a fragmentary sectional view of a known extension in which the locking ball bearing 24 bears directly on the retainer ball 25 dispensing with the force transmission shaft.
Fig. 8 is a fragmentary sectional view of another known extension in which multiple ball bearings 37 are utilized to transmit force from the control bar to the retainer ball.
Fig. 9 is a fragmentary sectional view in which a cylindrical detent 38 is utilized, extending completely through the transverse bore.
Fig. 10 constitutes a perspective view of an extension having a double locking configuration. Apparent in Fig. 10 are the common features including the sleeve 29 and control bar 14. The sleeve is rearwardly extended over the driven end of the shank. The rearward travel is permitted by and limited by a substantially L-shaped slot 42 machined through the surface of the sleeve 29. Retention of the sleeve is accomplished through the use of a pin 43, placed within the slot 42, and fixedly mounted in the shank. Fig. 11 is a fragmentary sectional view of the device of Fig. 10 in its released configuration. The interior of the rearward extension of the sleeve 29 is provided with a recess or recesses 40, into which the driven end locking ball 41 is carried, and permitted to retract in the release configuration. Further apparent is the locking slot 42 and pin 43. The operation of the driving end section, utilizing the detent 38, engaging a drive socket 21, acted upon by the control bar 14 is substantially the same as the other known extensions.
Fig. 12 is a fragmentary sectional view of a double locking extension in the locked configuration. The detent 38 engages the recess in the socket 21. The downward or inward pressure of the sleeve 29 is exerted upon the driven end detent 41, which detent itself mates with the standard detent of the driving member 45. Because the detent in the driving member 45 is spring loaded, it can be compressed below the driving surface by the locking detent 41.
Fig. 13 illustrates an exploded view of the double locking extension showing the components in a disassembled configuration. Assembly and disassembly is generally accomplished through removal of the retainer pin 43.
Fig. 14A illustrates a socket locking extension with a driven portion 11, shank 9 and square driving portion 12. The driving portion 12 fits into socket 21 for imparting rotational movement. The shank 9 terminates at a shoulder 27 at the end of the shank 9. A slot or channel 10 is formed in the surface of the shank and extends into one face or wall of the driving portion 12.
A control bar 14 which has an outer surface 13 is carried in the control bar channel. A raised portion or spur 16 extends outward from the outer surface 13 and fits into sleeve 15. The sleeve has internal annular engagement elements or flanges. In this extension these constitute an inner annular ring 28 and terminal annular ring 29 of the sleeve defining an annular groove 30 between them. This extension does not foreclose the use of other methods of engagement. The forward motion of the sleeve toward the driving end is limited by a circular clip 18 as in prior art arrangements. Rearward movement, however, is limited by a limiting collar 52 which engages the rear edge of the sleeve. Ideally the sleeve may be covered with a friction increasing surface pattern such as knurling 29 or other arrangements making the sleeve easy to grip and retract.
Fig. 15 is sectional view of this extension. The socket 21 has a plurality of faces 31 which engage the driving portion 12. Apparent in this view is a transverse bore 19 in which retainer balls 22 and 24 are carried. The clearances between the retainer balls and bore are such that a slight off center condition results in a camming action. The control bar 14 carried in the control bar channel 10 extends forward or toward the distal end 95 (to the left). The outer surface 13 of the control bar engages the socket surface 31 when in the locked position. The inner surface 50 of the control bar slides on the floor 60 of the channel 10. The inner surface 50 merges into a bevel 25. It has been found in development that a bevel angle of approximately 10 degrees is preferable in this extension. For improved clearance and engagement of the socket, the tip of the control bar is also bevelled 51, adjacent to the outer surface 13.
Further apparent in this view are the sleeve-control bar engagement elements 28 and 29 which engage the outwardly extending spur 16 of the control bar permitting retraction and imparting a forward (leftward) force through the action of a compressed coil spring 17. As noted in connection with Fig. 15 forward and radially outward motion is limited by circular clip 18 snapped into groove 96 in the shank although other appropriate structures may be used.
As shown in Fig. 16, the spring 17 is compressed between the engagement element 28 of the sleeve 15 and an opposing edge of the limiting collar 52. The limiting collar itself is carried on the shank and has an inner surface 55 carried on a reduced diameter shank surface 56. The end of the limiting collar 57 engages a shoulder 58 formed at the intersection of the reduced diameter surface 56 and outer surface of the shank. The limiting collar further incorporates an outwardly extending shoulder 54 formed around its circumference which engages the rearward end of the sleeve 15 at the rearward most extension of travel. This in turn retracts the control bar 14 and the retainer balls 22 and 24 are permitted by the movement of the bevel 25 to disengage from the socket face 31.
As shown in Fig. 18 the distance of travel permitted is less than the distance between the tip of the control bar and the point where the bevel 25 merges into the inner control bar surface 50. As a result of this arrangement in the locked position the retainer ball 22 continues to engage the bevel surface 25. This may be compared to US-A-4,480,511 where the forward travel of the control bar and rearward travel of the control bar was such that the flat surface engaged the retainer ball.
As shown in Fig. 17 there are several advantages to this arrangement. In the environment where the tool is likely to be utilized and given the typical dimensions and clearances of standardized sockets, the sockets frequently become canted, twisted and otherwise misaligned under the forces exerted thereon. This may result in the jamming of the tool rendering it difficult to the release the socket. Engagement of the retainer ball 22 cooperating with the socket engagement retainer ball 24 on the bevel surface 25 reduces the tendency to jam. Even slight retraction of the control bar 14 necessarily reduces the transverse dimension between the outer surface of the control bar and the outermost point of the retainer of the retainer ball 24 thereby reducing any transverse pressure across the tool. The increased ease of release permits the use of closer tolerances in the tool which permit improved gripping force because of the co-acting of rotational and wedging forces in the respective components. When a socket engaging the retainer ball 24 and control bar outer surface 13 on opposite walls is pulled forward (leftward) friction from the wall which engages the retainer ball 24 will tend to impart a rotation clockwise as shown by the arrows in Fig. 17. Near the point of tangency (considering the slight off center alignment of the balls) and near the point diametrically opposed thereto, the retainer ball 24 engages the other retainer ball 22. The rotation of the first ball 24 imparts a counter clockwise rotation in the second ball 22 also shown by arrows. A lateral force is transferred to the control bar bevel or wedging edge 25 and tends to impart a forward (leftward) motion to the control bar as shown by the arrow. This movement of the bar, because of the bevel arrangement, tightens the engagement of the retainer ball 24 with the control bar surface. Thus the bar is tightly wedged between the ball 22 and socket walls. The opposing surface 31 develops a tight frictional fit resisting the pulling of the socket off the tool in its locked position.
This permits the utilization of sockets whose interior walls do not have the recesses designed to engage retainer balls 24. In the field this provides increased utility as sockets may become worn, sockets may be produced with recesses on none of their interior walls 31 or sockets may be produced with recesses or equivalent structures on less than all of the walls as in the case of impact sockets. In this later instance a retainer ball expected to engage a recess would only engage the socket if a transverse hole extending from the outer surface of the socket through to the interior surface of socket is lined up with the retainer ball. This becomes cumbersome in the field and the present improved configuration permits the locking of said sockets even when flat walls are engaged by the retainer ball 24 and outer control bar surface 13.
Fig. 19 corresponds to Fig. 15 with the addition of a helical spring 61 interposed between the retainer balls 24 and 22. While in the released position the retainer balls are substantially free to move inward and outward within limits. A reduced diameter 62 of the transverse bore limits outward movement in a direction opposite the control bar and movement toward the control bar is limited either by the control bar itself or by reducing the diameter by machining flanges or tapering the bottom of the transverse bore during drilling and before machining the control bar channel. This loose carriage of the retainer balls provides substantially negligible resistance to the forward movement of the socket.
In Fig. 20 it is shown that the placement of the spring exerts an outward force on the retainer balls. This outward force provides for increased resistance against the wall of or recess in the wall of the socket, thereby reducing the likelihood of the socket falling off the tool when the control bar is retracted in the released position, either intentionally or accidently.
As illustrated in Fig. 17 and 18 the relative dimensions of retainer balls, spring and transverse bore diameter are such that in the locked position the retainer balls bear directly on one another resulting in the rotational and wedging action discussed with reference to the previous Figures. The spring diameter is nearly equal to that of the bore and in the locked position the spring is nearly fully compressed so that any deformation of the balls permits a fully compressed spring to bear some of the load. The use of the bevel or wedging-surface engagement described with reference to Fig. 15, Fig. 16, Fig. 17 and Fig. 18 and the use of the spring described in connection with Fig. 17 and Fig. 18 provide the highest degree of utility in use.
Fig. 21 shows a sectional view of a preferred embodiment in accordance with the first aspect of the present invention. This view is analogous to Fig. 15 and 17 which show the device in the locked position. It will be noted chat towards the rear (right) end of the control bar 14 the control bar bottom surface 50 has been notched 65. Rearward (to the right) of the notch is a downwardly projecting latch element 66 terminating along an extended imaginary line from the control bar bottom surface 50. A second transverse bore 68, which may constitute a blind bore extending partially downward from the control bar channel floor 60, is shown.
Fig. 22 shows this preferred embodiment with the tool in the released position. The spring 61 acting through retainer ball 22 exerts an upward force on the tip of the control bar. This, and the placement of the recess 68 in the channel floor 60, permits the downward biasing of the rear end of the control bar and corresponding upward biasing of the tip of the control bar. The downward biasing results in the engagement of the latch element 66 in the recess 68. Thus the mechanism is latched in the open position in this embodiment. This may be compared to other extensions where the spring 17 always returns the mechanism to the locked position thus requiring retraction both to remove and to place a socket on the driving end 12 of the tool. Release of the mechanism from its latch position is accomplished by the forcing of retainer ball 24 against spring 61 at point "a", permitting further insertion of the socket. Then the socket end 69 engages the bevel 51 on the tip of the control bar when the socket is further moved into the tool at point "b" of Fig. 22. The angle of this permits unlocking of the control bar by causing the downward biasing of the tip and corresponding upward biasing of the rear end of the control bar to the point where the latch element 68 disengages from the recess 68. The pressure of the spring 17 thereby locks the mechanism. This provides semi-automatic action by holding the control bar in a socket release position until replacement of a socket causes locking action.
Fig. 23 shows an alternative arrangement in which the securement portion of the tool is carried on a truncated body 80, of length limited to that necessary to carry the sleeve 15 and to provide for the stop limiting retraction of the sleeve. This extension is adapted to receive the driving end 81 of a second shank in corresponding recess 82 in the truncated body. Operation of the retainer mechanism is otherwise unchanged from the alternative extensions previously discussed. The recess for driving the truncated body by the second shank 83 is defined by walls that correspond to the driving portion 81 of the second shank 83.
The truncated body 80 is further attached to the second shank 83 in a semi-permanent manner through the insertion of a pin 84 in a hole 85 extending through one wall 86 of the truncated body's recess, through the driving portion 81 of the second shank 83 and through the opposing wall 87 of the driven recess of the truncated body. This pin may be inserted and maintained in place by a compression fit thereby resulting in a unitary extension tool. Alternatively a spring loaded pin permits adaptation to power driven extensions.
Fig. 24 shows an alternative truncated body arrangement. In this arrangement the pin 84 is carried in a hole 88 in the driving portion 81 of the second shank 83. In this case the pin 84 is of a rivet head or inverted "T" shaped section and the neck of the hole 85 is reduced in diameter to retain the pin. A spring 89 forces the pin outward and this permits easier removal by depressing the pin 85 with a suitable implement such as a probe, punch or the like. This is considered a semi permanent affixation because of the retention of the pin and need for an implement to remove the truncated body 80.
The use of the arrangement in Fig. 23 and 24 permits the use of dissimilar alloy metals in the truncated body and second shank, the use of differential treatment as by heat treating of the respective truncated body and second shank, and the repair of either the truncated body or the second shank without requiring replacement of both. A further advantage is that production can be streamlined because of the previous mentioned material and heat treatment flexibility. Further, the truncated body and second shank arrangement permits adaptation of various length second shanks which may be more easily conformed to specific consumer needs.
Fig. 25 and Fig. 26 shows a preferred embodiment of an extension in accordance with the second aspect of the present invention, which provides semi automatic retraction. In this preferred embodiment the control bar 14 has a recess 101 placed in its tip. This recess includes a face 102 substantially parallel to the axis of the control bar 14 and forms a shoulder 103 perpendicular thereto. The shoulder is placed at such a position that as a socket is installed, the retainer balls are forced upward and the control bar tip is biased upward so that it engages the base of the socket. Continued movement of the socket causes partial retraction of the control bar 14 against the pressure of the spring 17. The socket 21 moves rearward (to the right) to the point where there is sufficient clearance between the opposing walls 31 because of the reduced transverse dimension across the bevel 25 that the control bar 14 may move to the locked position.
Thus at least in the illustrated embodiments, the invention provides for the utilization of the locking and quick releasing feature as a supplement to the ratchet handle which may be made smaller yet stronger than the cumbersome quick release type ratchet handle. The embodiments utilize the camming engagement of two retainer balls and a camming control bar to provide wedging between the bar and balls for effectively locking an associated socket. They also use a spring co-acting with the retainer balls so as to prevent loss of an associated socket upon accidental release of the locking sleeve. One preferred embodiment utilizes a lock-back mechanism to increase the ease of placement of the socket on the tool. Another uses a securement portion as a separate structure from an extension shank. A further embodiment uses a notched control bar to provide for semi-automatic retraction.
The advantage in the use of a camming control bar is that the forces contributing to retention are increased under load. Another advantage is that engagement with a recess in a socket is less important than in any prior embodiments.
An advantage in the use of a spring co-acting with retainer balls is that a degree of increased friction is imparted between the drive extension and the socket walls even in the released position.
An advantage to the lock-back mechanism and the notch control bar embodiment are that either provides a degree of semi-automatic action in the retraction.

Claims

A socket wrench drive extension comprising:
an elongate main shank (9) including a first shank portion (11) at the rear end for receiving rotative motion and a second shank portion (12) at the forward end for transmitting the rotative motion to a releasably connected socket member (21),
a movable control bar (14) arranged in an axially extending channel (10) in the shank and slidably moveable between a forward locking position and a rearward release position by means of a movable sleeve (15) arranged about the main shank (9), said control bar (14) being urged towards the forward locking position by a spring (17) acting on the sleeve (15),
a transverse aperture (19) connecting the bottom of the channel (10) radially inwardly of the control bar (14) with the diametrically opposite side of the first shank portion (12) and accommodating locking means in the form of two retainer balls (22, 24), said balls and said aperture being so dimensioned that the balls at all times project from the ends of the aperture (19),
wherein the control bar (14) includes a radially outwardly directed surface (13) adapted to engage an inner wall (31) of the socket member (21) and a radially inwardly directed surface (50) adapted to engage the adjacent retainer ball (22) and via said engagement move the other retainer ball (24) towards a diametrically opposite inner wall (31) of the socket member (21) thereby effecting locking engagement between said socket member (21) and the wrench drive extension,
characterised in that,
the radially inwardly directed surface (50) of the control bar (14) includes a forward bevelled section (25) adjacent the locking means (22, 24) and a rear section with a notch (65) and a radially inwardly projecting latch element (66), the bevelled section (25) having such an axial extent that it contacts the adjacent retainer ball (22) both in the locking and the release position of the control bar (14),
the bottom of the channel (10) includes a recess (68) near its rear end and adjacent said latch element (66) of the control bar (14), and a spring (61) is interposed between the retainer balls (22, 24) to urge these apart thereby simultaneously exerting a radially outwardly directed force on the bevelled section (25) of the control bar (14) to impart thereto a tilting tendency, so that when the latch element (66) of the control bar (14) engages the recess (68) of the channel (10) the control bar (14) undergoes a limited tilting movement, thereby latching the control bar (14) in the release position.
A socket wrench drive extension comprising:
an elongate main shank (9) including a first shank portion (11) at the rear end for receiving rotative motion and a second shank portion (12) at the forward end for transmitting the rotative motion to a releasably connected socket member (21),
a movable control bar (14) arranged in an axially extending channel (10) in the shank and slidably moveable between a forward locking position and a rearward release position by means of a movable sleeve (15) arranged about the main shank (9), said control bar (14) being urged towards the forward locking position by a spring (17) acting on the sleeve (15),
a transverse aperture (19) connecting the bottom of the channel (10) radially inwardly of the control bar (14) with the diametrically opposite side of the first shank portion (12) and accommodating locking means in the form of two retainer balls (22,24), said balls and said aperture being so dimensioned that the balls at all times project from the ends of the aperture (19),
wherein the control bar (14) includes a radially outwardly directed surface (13) adapted to engage an inner wall (31) of the socket member (21) and a radially inwardly directed surface (50) adapted to engage the adjacent retainer ball (22) and via said engagement move the other retainer ball (24) towards a diametrically opposite inner wall (31) of the socket member (21) thereby effecting locking engagement between said socket member (21) and the wrench drive extension,
characterised in that,
the radially inwardly directed surface (50) of the control bar (14) includes a forward bevelled section (25) adjacent the locking means (22, 24) the bevelled section (25) having such an axial extent that it contacts the adjacent retainer ball (22) both in the locking and the release position of the control bar (14),
a spring (61) is interposed between the retainer balls (22, 24) to urge these apart thereby simultaneously exerting a radially outwardly directed force on the bevelled section (25) of the control bar (14) to impart thereto a tilting tendency, and
the radially outwardly directed forward end of the control bar (14) has a forwardly open recess (101) comprising a first surface (102) substantially parallel to the axis of the control bar and a second surface (103) perpendicular to the first surface and forming a rear end shoulder of the recess, wherein the second shoulder surface (103) is adapted to engage the end surface of the socket member (21) when the wrench extension is inserted into said socket thereby sliding the control bar (14) rearwardly towards the release position.
An extension as claimed in claim 1 or 2, wherein a second shank member (83) is semi-permanently attached to said first shank portion (11) to impart rotative motion thereto.
An extension as claimed in claim 3, wherein said second shank member (83) is attached to said first shank portion (11) by a compression fitted pin (84) extending therebetween.
An extension as claimed in claim 3, wherein said second shank member (83) is attached to said first shank portion (11) by a spring loaded displaceable pin (84) extending therebetween.
An extension as claimed in any preceding claim, wherein said main shank (9) has a pin (43) extending laterally therefrom, which projects through a slot (42) in the movable sleeve (15), said slot being substantially L-shaped such that a rotation of the sleeve with respect to the main shank (9), when the control bar (14) is in its forward locking position, results in the sleeve being locked in position with respect to the main shank.