UNIVERSALDRIVEFORAWRENCH —BACKGROUND OF THE INVENTION— This invention relates to spanners for power operated ratchet wrenches and the like. Power tools are advantageously used in many situations where rapid and continuous rotation of fasteners is required, they may be operated by electric, pneumatic, hydraulic or mechanical means- While our earlier International patent specifications describes power operated wrenches having advantages in relation to simplicity, compactness and/or ease of assembly, these benefits can be substantially ameliorated by the use of cumbersome drive adaptors for coupling the tool to spanner sockets and the like. —SUMMARY OF THE INVENTION—

This invention aims to provide accessories suitable for use with such and other tools and which will be reliable and efficient in use.

With the foregoing in view, this invention in one aspect resides broadly in a universal drive for a wrench having an open polygonal type drive ring, including:- a housing having either a polygonal outer surface or a splined outer surface for driving engagement with the drive ring and an open bore coaxial with the polygonal outer surface; a swivel ball closely accommodated in said open bore whereby the centre of the swivel member is locatable substantially within the bounds of the drive ring; locking means for locking said swivel ball against rotation within said bore, and drive means integral with said swivel ball and accessible externally of 'said housing.

Preferably the overall length of the housing is approximately the same as the axial length of a conventional spanner ring. It is also preferred that the housing is a thin walled hexagonal housing and the locking means for the swivel ball is a ulti faced ball having outer cylinder

shaped wall sections coincident with the inner side walls of the polygonal drive ring for driving engagement with the drive ring.

The drive means may be, for example, a polygonal socket within the swivel ball for an Allen key or screw driver bit or the like, or a square drive for a spanner socket. In a preferred embodiment of the invention the drive means is an integral relatively short stem extending from the drive ball and terminating as a hexagonal ball portion adapted for universal engagement within the hexagonal socket of an Allen head fastener.

Preferably the length of the drive stem and the permissible angular rotation of the swivel ball within the open bore are such that the further hexagonal ball portion may operate at a position spaced laterally from the drive axis of the swivel ball to an extent that the hexagonal ball portion may engage within and rotate an Allen head fastener about an axis parallel to the drive axis and offset therefrom by an amount equal to the maximum radius of the housing. With this arrangement, an Allen head fastener passing through a member and located adjacent a wall at right angles to the member, such as being spaced from the wall a distance equal to the head diameter of the fastener, may be accessed by the universal drive while maintaining the power wrench disposed with its drive axis parallel to the axis of the fastener. This is advantageous as a fixed drive requires the power wrench be disposed with its drive axis inclined to the axis of the fastener. Such inclination is often prevented by the member or an adjacent wall or other obstruction. The housing is suitably provided with an external collar disposed around the end thereof through which the drive means or driven member engaged therewith extends. The outer collar limits the pivotal movement of the ball within the housing and is suitably formed with a circular peripheral portion such that a smooth swivel action is achieved during rotation. Preferably the hexagonal ball portion is provided with a complementary collar such that the swiveling action provides

collar to collar rolling contact. Suitably the collar on the hexagonal ball portion is the same diameter as the outer diameter of the spherical ball from which the hexagonal ball is or could be machined whereby the workpiece may be held in a machining chuck for rotation about an axis coincident with the axis of the collar for machining the hexagonal faces on the ball.

The above arrangement achieves good tool accessability because of the compact construction and good operator feel as the positioning of the ball centre at or close to the centre of the drive ring alleviates the orbital movement associated with conventional universal drive bars. Thus this configuration facilitates control of the tool.

—BRIEF DESCRIPTION OF THE DRAWINGS— In order that this invention may be more readily understood and put into practical effect reference will now be made to the accompanying drawings, wherein:-

FIG. 1 is a perspective view of a ratchet wrench FIG. 2 illustrates a preferred form of universal Allen head drive according to one aspect of this invention

FIG. 3 illustrates a series of universal drive sockets made in accordance with the present invention; FIG. 4 illustrates the universal drive in section; FIG. 5 illustrates the workpiece from which the ball and drive means is machined;

FIG. 6 illustrates square drive universal adaptors; FIG. 7 illustrates a preferred form of spark plug spanner;

FIG. 8 illustrates a universal drive adapted for an alien key and

FIG. 9 illustrates typical square drives.

—DESCRIPTION OF THE PREFERRED EMBODIMENT— Referring to Fig. 1 it will be seen that the wrench assembly 10 is connected by a snap-on connection to an air drive motor 11 for rotation of the drive shaft 19, and through the oscillating mechanism 13, the hexagonal socket mounting 25.

In the illustrated embodiment, a reducing socket 14 is mounted within the open hexagonal drive socket 25 and it accommodates the hex head of a bolt 15 which is held captive in the socket by engagement of the slide clip 12 with the shank of the bolt 15. The bolt extends from one open end of the drive socket 25 and may be rotated by actuation of the air supply lever 16. It will be seen that the present arrangement will facilitate inserting a bolt into a mating threaded recess which is normally difficult to access. The bolt may be tightened to the limit of the torque available from the air motor through the oscillating mechanism 13 and subsequently manually tightened by use of the wrench assembly 10 as a conventional spanner. It will also be seen that the head of the bolt 15 is accommodated within the drive socket 25 so that rotation of the bolt by the wrench does not produce a load reaction spaced laterally from the drive socket 25, thus facilitating ease of use of the wrench.

The drive socket 25 may co-operate with different adaptors or sockets including those illustrated in Figs. 2-7 all of which have a common hexagonal head portion 20 adapted for driving engagement with the drive socket 25.

Each head portion 20 may be provided with a retaining groove 21 at the junction of each flat 22 and a spring-biased locking ball 21 may be provided in the drive socket 25 for engagement with one of the grooves 21 for retaining the head portions in their operative position engaged within the drive socket 25.

The head portion 20 is suitably machined from suitable strength bar material, machined with registering internal and external hexagonal surfaces 22 and 23 respectively. The internal hexagonal surface is adapted to co-operate with a hexagonal ball 24 formed integrally with and extending rearwardly from the hexagonal drive socket 26. Engagement of the hexagonal ball 24 within the hexagonal recess 22 provides driving engagement between the head portion 20 and the socket 26 and a degree of swiveling as indicated by the tilted

position of the drive socket 26 in dotted outline. For this purpose it will be seen that the drive socket 26 is necked at 27 intermediate the ball and the open socket portion 28 and the arrangement is such that the back face of the socket portion 29 rides against the leading chamfered annular edge portion 30 of the head portion 20 at maximum swiveling of the ball. This ensures that relatively smooth rotation is achieved when the elongate axis 31 of the socket assembly 26 is inclined to the central elongate axis of the head portion 20.

This arrangement also maintains the centre of rotation of the swiveling drive socket within the drive socket 25 and thus in line with the wrench handle so that offset loads apparent in conventional extension universal drives are not generated, making the wrench easier to operate. The universal drive of this invention may also be used to advantage with conventional ring spanners and the like.

It will be seen that the base 32 of the head portion 20 is provided with an internal recess for accommodating a compression spring 33 which biases the hexagonal ball 24 forwardly and into engagement with a retaining circlip 34. It is preferred that the socket assembly be machined from round section shaft 35 having an outer diameter equal to the outer diameter of the spherical ball 36 required for machining the hexagonal ball 24. This arrangement is illustrated in Fig. 5. After machining the spherical ball the part-machined article may be chucked in a lathe using the cylindrical end portion 38 which may be machined to form a socket or collar or other adaptor for the tool, and the hexagonal surfaces machined. At the same time the necked portion 27 may be machined which provides the necessary clearance for pivoting of the drive socket as illustrated.

Figs. 6-8 illustrate various inserts retained within the head portion to provide a universal drive for the respective inserts. These include square drives of various sizes as illustrated in Figs. 6a and 6b. A spark plug spanner is illustrated in Fig. 7 and an Allen key drive as illustrated

in Fig. 8. Fig. 9 illustrates fixed square drives in which the square drive shafts are machined integral with the head portions.

The spark plug spanner illustrated in Fig. 7 includes a universal drive of the type illustrated in Fig. 4 with the hexagonal socket 26 being in the form of an extended socket having an internal hexagonal leading portion 40, an intermediate resilient retainer 41 and an open inner end portion 42 adapted to accommodate the end of a spark plug. The arrangement is such that the retainer 41 is formed to resiliently engage about the insulating body of the spark plug and maintain the cap portion thereof free from the spanner so as to prevent contact therewith which, in conventional spanners, tends to result in cracking of the body of the spark plug. Furthermore, the resilient retainer enables a spark plug to be inserted in the spanner and held therein for remote insertion into a difficult to access spark plug opening.

The Allen key type spanner 60 illustrated in Fig. 2 includes a universal drive 61 of the type illustrated in Fig. 4 with the hexagonal socket 62 having a tapered stem 63 extending therefrom to a hexagonal ball end 64. The ball ends may be made in various sizes such as 6mm to 10mm to suit Allen key fasteners. It will be seen that the stem 63 is relatively short and thick for effective transfer of torque from the spanner to the fastener.

An advantage provided by the spanner 60 is clearly shown in the drawings where the spanner is shown driven by a wrench 10 of the type illustrated in Fig. 1 and operatively engaged with a Allen head bolt 65 located in a position which would be difficult to access with a conventional power wrench or with an Allen key which would require frequent engagement and disengagement of the key every half turn or less.

It will of course be realised that the above has been given only by way of illustrative example of the invention and that all such modifications and variations thereto as would be apparent to persons skilled in the art are deemed to

fall within the broad scope and ambit of the invention as is defined in the appended claims.