WO1989007509A1

WO1989007509A1 - Self-locking mechanism for square drive tools

Info

Publication number: WO1989007509A1
Application number: PCT/US1989/000216
Authority: WO
Inventors: Bernhard Palm
Original assignee: Bernhard Palm
Priority date: 1988-02-11
Filing date: 1989-01-19
Publication date: 1989-08-24

Abstract

A push-on/quick release locking arrangement is mounted on an extension (10) having a cylindrical body (12) and square drive end (14). An inclined transverse bore (16) in the drive end intersects opposed flat faces (34) and mounts lock balls (18) for movement between ''lock'' and ''release'' positions. A grip sleeve (42) with an integral tab (40) projecting from one end is mounted for slidable movement on the body such that the tab (40) is positioned within an axial groove (32) on a flat face intersecting the end of the bore further from the drive end. A coil spring (54) is held between a groove in the body and a shoulder of the sleeve so as to bias the sleeve towards the drive end and the tab (40) into the axial groove.

Description

-1- SELF-LOCKING MECHANISM FOR SQUARE DRIVE TOOLS BACKGROUND OF THE INVENTION

My U.S. Patent No. 4,537,100 shows a socket wrench extension with a push-on/quick release locking arrangement. While that design provided a function not previously available, the construction called for some costly production operations. My U.S. Patent No. 4,589,308 reduced the cost of the 4,537,100 design. This invention further simplifies the extension with consequent cost reduction.

SUMMARY OF THE INVENTION

This invention provides a push-on/quick release locking arrangement for a socket wrench "extension having a cylindrical body with a square drive end. Transverse offset bores or an inclined bore through the drive end intersects opposed flat faces. Lock balls are mounted in the bore for movement between a lock position in which one o^°f the balls projects from one end of the bore far enough to engage a cooperating cavity in the drive recess of a tool and a release position in which the ball lie within the cross section of the drive end. The end of the bore with the projecting ball is closer to the end of the drive end than is the other end oxv-t e^"-- bore. An axial groove is provided in the flat face: . intersected by the other end of said bore. A cylindrical sleeve is mounted on the cylindrical body ■5 of the extension. The end of the sleeve remote from the drive end is* turned inwardly and an integral control tab projects from the end of the sleeve closer to the drive end. A spring having a coil 0 captured in a groove in the cylindrical body bears against the slider to bias the slider and sleeve towards the drive end, and the tab projects from the slider into the axial groove to overlie the ball when said intuirned end of said slider abuts said coil. *5 This invention is an improvement over ^* the slider construction shown in my patent 4,589,308 in that the control tab is part of and integral with the "front" end of a sleeve which is turned in at the "rear" end to capture the biasing spring inside the 0 sleeve. The sleeve per se can be roll formed, machined or molded and includes an inside "front" shoulder against which the spring seats.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a "side" elevation of the present extension connected to a wrench socket.

Fig. 2 is an elevation rotated 90° from Fig. 1. -3-

Fig. 3 is a section on line 3-3 of Fig. 2 but with the extension and socket separated.

Fig. 4 shows the extension entering the recess in the socket with the sleeve and slider pushed back from the Fig. 3 position.

Fig. 5 is similar to Fig. 4, but the parts are now connected.

Fig. 6 is a section on line 6-6 in Fig. 3.

DETAILED DESCRIPTION OF THE DRAWINGS

The extension 10 has a solid round shaft 12 of the desired length. One end of the extension is provided with a recessed driven member (not shown) which is connected to and driven by the customary handle. The other end of the extension has a square driver 14 dimensioned to fit one of the standard socket sizes (such as 1/4", 3/8", 1/2", 3/4" or metrics). Driver 14 has a cross bore 16 in which two balls 18, 20 are retained by conventional coining operations at each end of the cross bore to reduce the opening to less than the ball diameter. As shown in Figs. 3-6, the cross bore is at 11.5° to a line perpendicular to the axis of the extension. This positions ball 18 closer to the end of the extension so ball 18 will first engage the side 22 of a recess -4 -

24 in a socket 26 as the extension m'σves into: the' socket recess.

As viewed in the drawings, an 'axial groove 32 intersects the cross bore. The groove lies in the middle of the flat drive face 34 and has a depth which when added to the length of the cross bore (measured from the bottom of the groove) is equal to the combined diameters of the two balls 18, 20. This permits the balls to lie wholly between the two opposed drive faces when the control tab 40 is moved to position the lock portion 36 in an unobstructing position. When the lock 36 is in the obstructing position shown in Figs. 3 and 5, ball 18 further from the tab must project to a lock position beyond the flat face of the driver. When the driver is inserted into the recess of a wrench socket, the projecting ball 18 will engage an undercut 38 in the recess 24, (as shown in Fig. 5) and the lock 36 will be backed up by the opposite wall of the recess to positively lock the socket in the extension until the lock 36 is manually withdrawn.

Tab 40 is integral with the reduced diameter portion 46 of sleeve 42 and is formed to position the lock 36 as described. The sleeve is formed to provide an inside shoulder 47 and groove 52. The right end of the sleeve is formed inwardly to capture the spring which houses spring 54 inside the sleeve 42. The right end of the spring has a tight coil received in a groove 56 in the extension so the other end of the spring bears against shoulder 47. This biases the sleeve to the left so lock tab 36 will normally lie in the groove 32. When the sleeve is pulled back (right) the tab 36 is moved away from the balls to permit the socket to be removed.

When the parts are assembled, the balls 18, 20 are placed in the cross bore 16 and the ends of the bore are then coined. The spring 54 is then placed inside the sleeve. The loose assembly is then

_* moved once the cylindrical end of the extension until the reduced diameter end loop of the spring snaps into groove 56. This is a permanent assembly. The only way to now remove the sleeve is to destroy it. The spring limits movement of the sleeve. Sleeve movement to the left is limited by end 60 engaging the spring loop engaged in -the groove. Spring movement to the right is limited by front end 58 closing (stacking) the spring loops against the spring loop captured in the groove 56.

The sleeve 42 has enough clearance on the extension to allow the sleeve to rock on the extension which means the lock tab can be moved into position to be engaged by the socket. This coupled with the angle disposition of the cross bore, makes it possible to push the socket onto the extension. Thus, as shown in Fig. 3, the ball 18 projects from -6-

the cross bore because tab 36 is self-biased to press*. down on ball 20. The entry into the socket recess .24 is slightly beveled or chamfered. This will cam the-. ball 18 (a sharp corner would also cam the ball) tσ push the balls 18, 20 upwardly and move tab 36 upwardly. The end of tab 36 will strike the bevel or face of the socket and will push tab 36 to the right relative to the extension as the extension enters the recess. This pushes the sleeve to the right, compressing spring 54 as shown in Fig. 4. When the ball 18 reaches the undercut, the spring 54 forces the tab 35 to the left to force the balls 18, 20 down so ball 18 engages the undercut 38. This locks the socket in the extension until the sleeve is manually - retracted to allow the balls to move into the cross bore and permit the socket to be removed. The socket has been mounted simply by pushing it on the end of the extension. The spring acts on the sleeve to always bias the tab into the groove. The reduced diameter portion 46 can be any desired length to allow adequate finger room between the sleeve and the socket. I claim:

Claims

-1-

CLAIMS 1. A socket wrench extension provided with a push-on/quick release locking arrangement comprising, a drive end on said extension having an even number of flat drive surfaces and having an axis, a cross bore through the drive end ^• intersecting opposed flat surfaces, said cross bore having an axis and an end at each of said opposed flat surfaces intersected by said bore, lock means mounted in said bore having a length generally equal to the distance between said opposed surfaces, an axial groove in one of said opposed flat surfaces, the axis of said cross bore being angled relative to a line perpendicular to an axis of the extension so the end of the bore at the other of said opposed surfaces is closer to an end of the extension, means retaining said lock means relative to said bore while allowing limited projection of the lock means to a lock position beyond said other surfaces, an axially movable sleeve mounted on said extension for movement between a locked position and a released position, (Claim 1 con ' t . )

said sleeve having an interior groove having front and rear walls, a portion located between said drive end and said interior groove, a control tab integral with said sleeve portion and formed to project forwardly into said groove, said control tab including a lock tab in said axial groove operative to obstruct movement of said lock means into said groove when the slider is in a locked position whereby the lock means, projects from said other of said opposed flat surfaces, said lock tab being retracted from said locked position when said sleeve is moved to its released position whereby said lock tab no longer obstructs said lock means and the lock means can move into the bore, a spring mounted in said interior ^' groove in said sleeve and bearing against said other axially spaced portion of said slider to bias the sleeve and slider to said locked position, said sleeve having enough clearance on said extension to accommodate some rocking of the sleeve on the extension whereby the lock tab can be raised by said lock means when said lock means is moved into said cross bore. 2. A socket wrench extension according to Claim 1 including, an annular groove in the extension near said drive end, 3 loop of said spring remote from the drive end being engaged in said annular groove, movement of the sleeve toward said drive end being limited by engagement of said rear wall with said spring loop.