GB2127728A - Wrench - Google Patents

Abstract

A wrench includes a handle (2) to which is pivotally attached a head (3) having a fixed jaw (4) and a movable jaw (5) biased towards each other by a spring. A member (11) on the movable jaw (5) abuts against a stop (12) on the handle (2) to prevent the jaws moving apart when turning a nut. Between each turning operation the handle (2) is moved in the opposite direction and the head (3) and handle (2) pivot apart. The member (11) then disengages from the stop (12) so that the movable jaw (5) can move away from the fixed jaw (4) against the action of the spring so that the jaws ride over the nut (a) and do not turn it. On moving the handle (2) back in the original direction, the head (3) and handle (2) pivot towards each other and the member (11) again abuts against the stop (12). In another embodiment Figs. 6 to 9 the jaws are adjustable by a worm and a rack carried by the slidable jaw. <IMAGE>

Description

SPECIFICATION Wrench This invention relates to a wrench. In a conventional, standard wrench, the handle is constructed integrally with a head having a pair of jaws, one of which may be movable in the case of an adjustable wrench. Turning the handle in either direction correspondingly turns e.g. a nut or bolt head in such direction.

In order that a screwing (or unscrewing) operation may be conducted continuously, it is generaliy necessary to remove the head from the object being screwed, at intervals, so that the wrench can be moved back to a starting position without turning the object. Thus, such a wrench is undesirable to the extent that continuous screwing is operated with difficulty and work efficiency is not high. In view of this, there have been proposed ratchet wrenches designed so that the jaws turn in one direction only even though the handle is turned repeatedly in both directions.

Thus the jaws are kept in contact with the object being screwed, and there is no need to remove the wrench each time from the object being screwed.

However, such ratchet wrenches have disadvantages in that they are expensive because their structure is complicated and they are large.

According to this invention there is provided a wrench including a handle member, a head member having a stationary jaw and a moving jaw, means pivotally supporting said head member at one end of said handle member, and biasing means for urging said moving jaw towards said stationary jaw, said moving jaw being provided with inhibiting means adapted to engage an engaging element provided on said handle member for inhibiting the moving jaw from moving away from the stationary jaw during turning of the wrench in one direction so as to act on a member disposed between the jaws and the arrangement being such that when the wrench is turned in the opposite direction whilst the member is still disposed between the jaws, said inhibiting means disengages from said engaging element whereby the moving jaw is allowed to move away from the stationary jaw against the action of the biasing means.

Thus, the wrench can be used in a manner similar to a ratchet wrench yet can be of simple construction and cheap to manufacture.

Preferably there are included means for adjusting the distance between the stationary and movable jaws so as to account for different sizes of member to be acted upon by the wrench. In one such embodiment the adjusting means includes an adjusting screw that meshes with teeth provided on the moving jaw, the inhibiting means being supported on the adjusting screw.

Some embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:- Figure 1 is a perspective view of a first embodiment of a wrench in accordance with the invention; Figure 2 is a partly broken main part plan view illustrating the operating state of the wrench in Fig. 1; Figure 3 is a partly broken main part front view of the wrench of Fig. 1; Figure 4 is a main part plane view illustrating the operating state of the wrench of Fig. 1; Figure 5 is a main part plan view illustrating a modified embodiment of the wrench of Fig. 1; Figure 6 is a perspective view of a second embodiment of a wrench according to this invention; Figure 7 is a main part perspective view illustrating disassembled constituting members of the wrench of Fig. 6: and Figures 8 and 9 are partly broken main part plan views illustrating operating states of the wrench of Fig. 6.

Referring to the attached drawings, in Figs. 1 to 5, there is shown a first embodiment of a wrench in accordance with the invention. This wrench 1 includes a handle member 2 and a head member 3. This head member 3 has a stationary jaw 4 and a moving jaw 5, and is turnably supported on a fixing plate 6 attached to one end part of said handle member 2 by virtue of a pivot 7. On the side of the pivot 7 of the head member 3 there is formed a fitting groove 8. In this groove 8 there is fitted the upper half of the fixing plate 6 on the side of pivot 7. In the head member 3 opposed to the lower half of fixing plate 6 there is formed a slide groove 9. In this groove 9 there is slidably fitted a base part 10 of the moving jaw 5. This base part 10 is substantially thinner than the moving jaw 5.On the end surface of base part 10 in the direction opposed to the moving jaw 5 there is formed an inhibiting means 11 whose thickness is substantially the same as that of the moving jaw 5. This inhibiting means 11 is in the form of a lug designed to engage an abutment or engaging part, 12, formed at the lower half of the fixing plate 6, in the state shown and inhibits the moving jaw 5 from moving away from the stationary jaw 4. At the central part of the head member 3 there is formed a hollow 1 3 substantially parallel with the fitting groove 8, one end of said hollow 1 3 opening in the slide groove 9.A spring seat 14 is disposed in the hollow 1 3. Between the spring seat 14 and the moving jaw 5 facing the hollow 1 3 there is interposed a spring 1 5 that acts to bias the moving jaw towards the stationary jaw. The arrangement is such that the movable jaw can only move to a certain predetermined distance away from the stationary jaw, corresponding to the size of nut to be turned.

Reference wiil be made to the-operation of the above embodiment as follows: As shown in Figure 2, when screwing an object namely a nut a, the handle member 2 is turned downwards in the direction of the arrow while the stationary jaw 4 and moving jaw 5 of the head member are maintained engaged with the flats a, of said nut a. In this normal state, the inhibiting means 11 formed at the base part 10 of the moving jaw 5 engages the engaging part 12 of the fixing plate 6 so that the moving jaw 5 is inhibited from moving away from the stationary jaw 4. Due to this, the turning force of the handle member 2 is exerted upon the stationary jaw 4 and the moving jaw 5 so that the nut a is turned and screwed up.

When further screwing the nut a up, as shown in Fig. 4, the handle member 2 is turned upwards in the direction of the arrow to such an angle that the end face 21 of the fixing plate 6 on the side of the pivot 7 abuts the bottom of the fitting groove 8 formed in the head member 3 while the stationary jaw 4 and moving jaw 5 are maintained in engagement with the nut. This turning disengages the engaging part 12 from the inhibiting means 11 and exerts, on the moving jaw 5, the reaction force generated at the time when turning the handle member 2 further upwards. As a result of this, the moving jaw 5 is allowed to move against the biasing force of the spring 1 5 thereby to loosen the engagement with the nut a. When keeping on turning the handle member 2 upwards with the nut a as the pivot axis, the stationary jaw 4 and moving jaw 5 ride over peaks a2 of the nut a.Since the moving jaw 5 is biased towards the stationary jaw by the action of the spring 1 5 at this time, directly after riding over a peak a2 the stationary jaw and the moving jaw comes to engage the next flat a1 of the nut a. Thereafter, when turning the handle member 2 downwards by a predetermined angle as shown in Fig. 2, the engaging part 12 of the fitting plate 6 engages the inhibiting means 11 of the moving jaw 5 again and the end face 21 of the fitting plate 6 is separated from the bottom of the fitting groove 8, whereby the original normal state is restored and the nut a can be screwed up by turning the handle member 2 downwards again, as mentioned previously, from this normal state.

As mentioned above, the nut a is screwed up gradually and tightly by repeatedly turning the handle member 2 in opposite directions, namely downwards and upwards, while maintaining engagement of the stationary jaw 4 and the moving jaw 5 of the head member 3 with the nut a. Accordingly, this wrench 1 can screw the nut a continuously as can a ratchet wrench by turning repeatedly without the trouble of removing the head member 3 each time from the nut a, in spite of its simple structure, and can enhance work efficiency markedly. In addition, this wrench 1 can be manufactured cheaply because its structure is simple.

Fig. 5 shows a modification of the aforesaid embodiment. According to this modified embodiment, a spring bearing plate 17, whose section is C-shaped, is attached to the lower end surface of the head member 3 where the slide groove 9 has been formed. Between the spring bearing plate 1 7 and the base part 10 of the moving jaw 5 there is interposed a spring 1 8 that biases the moving jaw 5 towards the stationary jaw 4. The upper half of the fixing plate 6 is substantially thinner than the lower half thereof because stepped parts 1 9 have been formed on both sides of said upper half, and an inhibiting means 20 is formed to be larger than the inhibiting means 11.

In Figs. 6 to 9, there is shown a second embodiment of a wrench in accordance with this invention. This wrench 3 1 is an adjustable wrench and is basically different from the above mentioned wrench in that the distance between a stationary jaw 34 and a moving jaw 35 that engage the nut a can be adjusted as desired.

In the wrench 31, a stepped part 37 is formed at the connecting base part of each surface of a fixing platge 36. In a head member 33 there is formed a fitting groove 38 that fits up to the location adjacent to the stepped part 37 of the fixing plate 36. A slide groove 39 is formed in the head member 33 in the direction opposite to this fitting groove 38. In this slide groove 39 there is slidably fitted a base part 40 of the moving jaw 35.

This base part 40 is substantially thinner than the moving jaw 35, and is provided with teeth 41 spaced apart in the longitudinal direction. An adjusting screw 42 meshes with the teeth 41 so that the distance between the stationary jaw 34 and the moving jaw 35 may be arranged properly by sliding the base part 40 along the slide groove 39 by the action of the adjusting screw 42. The adjusting screw 42 is received in a rectangular opening 43 formed in the head member 32 and held in place by a guide rod 44. This guide rod 44 is designed so that one end part is screw-attached to the head member 32 and the other end part is located in a slide groove 38. In the slide groove 45 there is slidably fitted a slider 46 that is mounted on another end part of the guide rod 44 adjoining the adjusting screw 42.The slider 46 is provided with an inhibiting means 49 that is prevented from rotating by slidably fitting in the fitting groove 38 and operates to inhibit the moving jaw 35 from moving away from the stationary jaw 34 by engaging an engaging part 48 in the normal state, the engaging part 48 being formed at the end part of the fitting plate 36 in the direction opposite to a pivot 47. Further, the slider 46 has a recessed part 50. Between the recessed part 50 and an engaging collar 51 provided at the edge of another end part of the guide rod 44 there is interposed a spring 52 that actuates the slider 46 to bias the moving jaw 35 through the adjusting screw 42 towards the stationary jaw 34.

Reference numeral 53 denotes a spring interposed between the fixing plate 6 and the head member 3.

In this embodiment, as shown in Figs. 8 and 9, when a reaction force is exerted on the moving jaw 35, the adjusting screw 42 and the slider 46 move on the guide rod 44 toward the engaging collar 51 against the biasing force of the spring 52 together with the moving jaw 35, and when the stationary jaw 34 and the moving jaw 35 have ridden over a peak a2 of the nut a, the adjusting screw and the slider move in the direction opposite thereto together with the moving jaw 35.

Aside from the different structures, as discussed above, this embodiment operates substantially in the same way as the previous embodiments. In this embodiment, furthermore, when screwing up different-sized nuts a, the adjusting screw 42 is turned so to move the moving jaw 35 towards or away from the stationary jaw 34 and thus the distance between the stationary jaw 34 and the moving jaw 35 can be properly adjusted.

Claims (9)

1. A wrench including a handle member, a head member having a stationary jaw and a moving jaw, means pivotally supporting said head member at one end of said handle member, and biasing means for urging said moving jaw towards said stationary jaw, said moving jaw being provided with inhibiting means adapted to engage an engaging element provided on said handle member for inhibiting the moving jaw from moving away from the stationary jaw during turning of the wrench in one direction so as to act on a member disposed between the jaws, and the arrangement being such that when the wrench is turned in the opposite direction whilst the member is still disposed between the jaws, said inhibiting means disengages from said engaging element whereby the moving jaw is allowed to move away from the stationary jaw against the action of the biasing means.

2. A wrench according to claim 1 wherein said biasing means is disposed in a hollow formed in said head member.

3. A wrench according to claim 1 or 2 wherein said inhibiting means is formed as a part of said moving jaw.

4. A wrench according to claim 1 including means for adjusting the distance between the stationary and movable jaws so as to account for different sizes of member to be acted upon by the wrench.

5. A wrench according to claim 4, wherein said inhibiting means is carried by said adjusting means.

6. A wrench according to claim 5 wherein said adjusting means includes an adjusting screw that meshes with teeth provided on the moving jaw, the inhibiting means being supported on the adjusting screw.

7. A wrench according to claim 6 wherein said inhibiting means fits slidably in a slide groove formed in said head member.

8. A wrench, substantially as hereinbefore described with reference to Figs. 1 to 4, or as modified with reference to Fig. 5, of the accompanying drawings.

9. A wrench, substantially as hereinbefore described with reference to Figs. 6 to 9 of the accompanying drawings.