Adjustable socket wrench

Abstract

An adjustable socket wrench comprising at least two gripping jaws having a concave adjusting portion which protrudes through notches in a tubular head. An adjusting socket encircles the head and is provided with means, which in cooperation with said concave surface of the gripping jaws make the jaws pivot on a guiding device between the jaws when the adjusting socket is advanced longitudinally relative to the socket wrench.

Description

The present invention relates to an adjustable socket wrench comprising a head substantially circular in cross section, at least two gripping jaws symmetrical with regard to the vertical axis of the head, said gripping jaws consisting of a protruding gripping portion and an adjusting portion extending into the head, and an adjusting socket encircling the head and the adjusting portions of the gripping jaws, which socket is displaceable in the direction of the vertical axis of the head in relation to the head.

Adjustable socket wrenches which are intended to replace a whole series of fixed socket wrenches are known. A typical adjustable socket wrench is shown in U.S. Pat. No. 2,850,931, which socket wrench is furnished with two gripping jaws which by turning of an adjustable socket can be made to move toward and away from each other. A reduction in the jaw diameter is achieved by means of turning the adjustable socket so that the gripping jaws are urged to move away from a head. By means of guiding pivots placed transversely of the vertical axis and extending through angularly disposed notches in the gripping jaws, the gripping jaws are at the same time urged to move toward each other, whereby the jaw diameter is diminished. An increase in the diameter is produced by turning the adjusting socket in the opposite direction, whereby coil tension springs between the gripping jaws and the head pull the jaws away from each other owing to a cooperation of said pivots and notches.

An adjustable socket wrench of this type has serious drawbacks. The number of gripping jaws is limited to two, since the use of three gripping jaws would render the construction, which as such is complicated, much more complicated. The pivot-notch guidance is not very successful in this connection, since there is a great risk that the formation of rust after a period of use will hamper and finally completely stop the movement of the gripping jaws. This is especially true in regard to the jaw enlargening movement produced by the coil springs, since the tensile force of the coil springs decreases after a period of use. It is therefore probable that the adjustable socket wrench according to U.S. Pat. No. 2,850,931 will cease to function after a period of use.

An object of the present invention is to eliminate these drawbacks and to provide an adjustable socket wrench of a simple construction, in which the movements of the gripping jaws, both ways, are guided with force without the aid of any springs. This object is achieved by the adjustable socket wrench according to the present invention which is mainly characterized in that the socket wrench is equipped with a guiding device located on the vertical axis of the head, which device is fastened to the head and which supports the adjusting portions of the gripping jaws, the surface of the adjusting portions which is turned outward from the vertical axis of the head being substantially concave, the adjusting socket being equipped with a member supporting said concave surface, whereby the size of the jaw of the socket wrench is adjusted by moving said supporting member of the socket wrench in the direction of the vertical axis along the concave surface of the adjusting portions, whereby the gripping jaws are made to swing around the guiding device. Since the movements of the gripping jaws are produced both ways directly by the adjusting socket, there is no risk of endangering, in due course, the efficiency of the socket wrench due to springs, the spring power of which has diminished. In addition, the construction is very simple and sturdy.

An advantageous embodiment of the socket wrench according to the invention is described in greater detail hereafter with reference to the attached drawing, wherein

FIG. 1 shows the adjustable socket wrench according to the invention in a closed position,

FIG. 2 shows the socket wrench in cross section along line II--II in FIG. 3 in an open position,

FIG. 3 shows the socket wrench from above in an open position,

FIG. 4 shows the retaining ring in side view, partly in cross section,

FIG. 5 shows the retaining ring from above,

FIG. 6 shows the head in side view,

FIG. 7 shows the head from above,

FIG. 8 shows the head from below,

FIG. 9 shows the inner side of one of the gripping jaws,

FIG. 10 shows the gripping jaw according to FIG. 9 in side view,

FIG. 11 shows the gripping jaw according to FIG. 9 from above, and

FIG. 12 shows the gripping jaw according to FIG. 10 from below.

The adjustable socket wrench according to the drawing consists essentially of a head 1 substantially circular in cross section, three gripping jaws 2 symmetrically disposed with regard to the vertical axis of the head and extending into the head, and an adjusting socket 3 encircling the head, which socket is placed on the head 1 by means of threads 4. Threadably attached to the head is a screw 5 located on the vertical axis of the head and supporting at its other end a guiding device 6, which is essentially of a ball-shape. Fastened to the upper end of the head is a cover with a screw 8, and between the adjusting socket 3 and the cover 7 is arranged a retaining ring 9, which is pressed against the adjusting socket by a spring 10. The retaining ring 9 has a projection 11 fitting in grooves 12 at the upper edge of the adjusting socket 3. The inner periphery of the retaining ring 9 also has a projection 13 fitting in a channel 14 in the head 1 (FIG. 6), whereby the retaining ring is prevented from rotating around the head.

The gripping jaws 2 consist essentially of two portions, a gripping portion 15 protruding from the head, and an adjusting portion 16 essentially located within the head. The gripping portion is equipped with a groove 17, in which e.g., a nut can be fitted.

The adjusting portion of each jaw has on its side turned toward the vertical axis a recess 18 of such shape that the ball-shaped guiding device 6 is fitted therein. The opposite side of the adjusting portion is substantially concave. Right in front of the adjusting portions, the head 1 is furnished with longitudinal notches 19 (FIG. 6) locking the gripping jaws laterally when turning the socket wrench and through which the adjusting portions may partly protrude. As can be seen especially from FIGS. 9 and 10, the lower gripping portion of the gripping jaws is considerably wider than the upper adjusting portion, and the adjusting portion is in general curved.

The inner surface of the adjusting socket 3 has a peripheral bulge 20, the upper edge of which (FIG. 2) supports the concave surface of the protruding adjusting portion at a point above the guiding device 6. In addition, the lower edge of the adjusting socket 3 abuts the concave surface of the adjusting portion at a point below the guiding device 6 (FIG. 2). The gripping jaws 2 thus have three supporting points, i.e., the two above mentioned points on the concave surface as well as the supporting surface against the guiding device 6 located between the two first mentioned points. The adjusting portion accordingly forms a lever arm.

The adjustable socket wrench according to the invention operates as follows:

When the socket wrench is opened from the closed position in FIG. 1 to the position in FIG. 2, the retaining ring is lifted upwards against the action of the coil spring 10 until the projection 11 is located above the upper edge of the adjusting socket, whereby the retaining ring no longer prevents the turning motion of the adjusting socket. Thereafter the adjusting socket 3 is turned until the projection 11 is located right above a groove 12, at which the measure of the nut or screw head to be turned is indicated. When turning the adjusting socket 3, it rises at the same time upwards (FIG. 2) in the direction of the vertical axis due to the action of the threads. Hereby the supporting points of the adjusting socket bearing against the concave surface of the adjusting portion move upwards, as a result of which the gripping portions of the gripping jaws move away from each other and the upper ends of the adjusting portions move toward each other. Thus the gripping jaws perform a pivoting movement around the guiding device 6 under a guided motion of the bulge 20 and the lower edge 21 of the adjusting socket. When the opening between the gripping jaws is of a desired size, the retaining ring 9 is released and it moves downwardly onto the adjusting socket so that the projection 11 enters the desired groove 12, whereby the adjusting socket is locked with respect to the head. Finally an ordinary lever arm is inserted in an opening 22 in the head, and the nut engaged in the jaws is turned.

When turning the adjusting socket in the opposite direction, the supporting points of the adjusting socket bearing against the concave surfaces of the adjusting portions of the jaws move downwards in FIG. 2, as a result of which the gripping portions of the jaws move toward each other.

It should be noted that the range of regulation of the socket wrench can easily be adjusted by raising or lowering the guiding device 6 (FIG. 2), which in turn is effected by turning the screw 5.

The drawing and description are only intended to illustrate the concept of the invention, and the socket wrench according to the invention can be considerably varied within the framework of the appended claims. The number of gripping jaws can, of course, deviate from three, since the construction in no way prevents the use, for example, of two gripping jaws. Likewise, the supporting member of the adjusting socket (the bulge 20 and the lower edge of the socket) can be formed in a number of different ways without departing from the lever arm principle. The guiding surface of the adjusting portion has been referred to as concave, but it need not be such in the strictest sense of the word, and in practice, for example, a saddle-shaped surface according to the drawing is more fit for this purpose.

Claims

What I claim Is;

1. In an adjustable socket wrench having a substantially vertical head which is substantially circular in cross section, at least two gripping jaws symmetrically disposed with regard to the vertical axis of the head, each jaw having a protruding gripping portion, and an adjusting portion extending into the head and through a notch provided in said head, and an adjusting socket surroudning the head and the adjusting portions of the gripping jaws, said socket being mounted on the head so as to be vertically movable thereon, an improvement comprising a guiding device mounted on the vertical axis of the head and pivotably supporting the adjusting portions of said gripping jaws, said adjusting portions of the jaws having outer surfaces which are substantially concave, said adjusting socket including means for contacting said concave surface of each jaw to adjust the size of the jaws of the socket wrench by relative vertical movement of said adjusting socket with respect to said head to cause the gripping jaws to pivot around said guiding device.

2. An adjustable socket wrench according to claim 1, wherein said guiding device comprises a ball and a shank supporting said ball and threaded in said head such that the position of the ball with regard to the head can be adjusted by threadably adjusting the shank in the head, said adjusting portions of the gripping jaws having corresponding recesses which accommodate said ball.

3. An adjustable socket wrench according to claim 1, wherein the notches in the head extend longitudinally adjacent said adjusting portions, said adjusting portions extending through said notches so that the concave surfaces of said adjusting portions abut said means on the adjusting socket which adjusts the size of the jaws of the wrench.

4. An adjustable socket wrench according to claim 1, wherein said means on the adjusting socket contact each said concave surface at two points respectively located above and below said guiding device.

5. An adjustable socket wrench according to claim 4, wherein said means on the adjusting socket for contacting said adjusting portion of each jaw comprises an encircling bulge on the inner surface of said adjusting socket and a lower edge of the adjusting socket.