Technical Field

The invention relates to a wrench with a hook-shaped top jaw and a bottom -jaw adjustable thereto. The bottom jaw is carried by a slide which is disposed glidable along a guide integral with the top jaw at an angle to the gripping surfaces of the jaws. With the aid of setting means the slid is preferably lockable against movement along the guide, sai means at least inhibiting movement along the guide in the direction parting the jaws. The bottom jaw may be moved rela tive the slide towards and away from the gripping surface of the top jaw with the aid of a lever, supplemented by a toggl mechanism, which has its "loose" link connected to the bottom jaw, while its other link is a part of the lever on the oppo site side of its fulcrum, which is disposed in the slide, th free end of the lever forming a handle. Background Art

Conventional pipe wrenches without toggle-action levers e.g. according to Swedish Patent 1636, in which the bottom jaw merges into a shank on the back of the wrench, are adapt for automatically keeping their jaws heavily urged against the pipe for turning it, when the wrench is urged to turn by a force being applied from the back of the wrench towards th shank situated there. The shanks thus do not need to be pressed together by a grip over both of them when the wrench is urged in this direction. On the other hand, no such auto- matic bite is obtained if the wrench is urged in the opposit direction, and both shanks must be pressed heavily together during the turning action in this reverse direction for the jaws to maintain their grip on the pipe.

A pipe wrench of the kind described in the introduction, with a toggle-action lever, is known from the Swedish Patent 128 272. After being applied to, and clamped fast about the pipe, this wrench is intended to be locked with its jaws in an active position by the toggle-action lever being brought over its dead centre in the final phase of the bite. Turning

the pipe can then be done in either direction, but the wrench is very time-consuming to work with, as a result of the need of repeated disengagement and locking of the grip by moving the toggle-action lever past dead centre each time. When using the wrench without bringing the toggle link past dead centre the automatic tightening of the jaws is only afforded in one turning direction, namely the oppo¬ site to what is the case with the wrench according to the Swedish Patent 1636, i.e. for the application of a force, towards the shank associated with the bottom jaw and con¬ stituting a part of the toggle-action lever.

]?or single-shank pipe wrenches of conventional kind, e.g. according to Swedish Patent 156 998, there is obtained automatic tightening of the jaws in one pulling direction only.

ETone of the known wrenches described in the three patents mentioned can thus afford automatic tightening of the jaws in more than one of both working directions. The single-shank wrench is entirely unusable in the backward direction, while the twG-βhank kinds may of necessity be used in their backward direction, both shanks of the wrench having to be pressed together heavily during turning for the jaws to maintain their bite on the pipe or, as far as the wrench in the Swedish Patent 128 272 is concerned, urged to- gether to the locking position before each pull. This is an essential drawback with the previously known pipe wrenches. When the wrench is used in confined working spaces it is namely quite often entirely impossible to apply the wrench in such a position that on being pulled it automatically bites, although it could have found room if it had been applied in a position for pulling backwards.

It is indeed known from Swedish Patent 3309 to form a very primitive pipe tool in such a way that it affords an automatic bite on the pipe in both turning directions. How- ever, this tool cannot be made adjustable to the extent which would have been required for it to have obtained any practical and commercial importance.

Disclosure of Invention

The object of the invention is therefore to provide, for a conventional and generally accepted basic type of easily adjustable wrench, a solution which gives the wrench an automatic bite on the workpiece independent of the turn¬ ing direction.

The desired result is obtained by the wrench having been given the characterizing features apparent from the ollowing claim 1. Brief Description of Drawings

Some embodiments of the invention will now be described in detail with reference to. the appended drawings.

Pigure 1 is a side view of a two-shank pipe wrench in accordance with a first embodiment of .the invention. Pigure 2 is a perspective view of a second embodiment, this also being a two-shank pipe wrench.

Pigure 3 is a side view of a single-shank pipe wrench, constituting a third embodiment of the invention.

Pigure 4 is a sectioned partial view illustrating the mechanism in the slide of the wrench according to Pigure 3. Best Mode for Carrying out the Invention

The wrench according to Pig. 1 has a hook-shaped top jaw 1 and a bottom jaw 2 adjustable in relation thereto. The bottom jaw 2 is carried by a slide 3, glidably arranged a- long a guide portion 4, which is integral with the top jaw 1 , and extends from it at an angle to the gripping sur aces 5 on the jaws.

In the embodiment according to Pigure 1 , the slide 3 is lockable against movement along the guide portion 4 by the use of setting means. Said means comprise a screw 6 in an internal thread 7 made in the bottom end of the guide portion and extending therein up to the slide 3j the end 8 of the screw 6 being rotatably carried in said slide, which is thus adjustable to a desired position by turning the screw 6. The guide portion 4 has a longitudinal groove 4a, not discernible in the figure, for accommodating a web portion of the slide which is thinner than the rest of it. The bottom jaw 2 constitutes a jaw block which is

movable on the slide 3 towards and away from the gripping surface 5 of the top jaw 1 , with the aid of a toggle-action lever, the implementation of which is not apparent from Pigure 1 but is of the same kind as illustrated in Pigure 4-. Prom the latter figure it will be seen that one link 9, the "loose" link, is connected to the jaw block 2. The link 9 comprises two parallel plates, one on either side of the dependent portion 10 of the jaw 2, only one of these plates being visible in Pigure 4, the link being pivotably joined to the portion 10 with the aid of a pin 11. As distinguished from what is illustrated in Pigure 4, the jaw block 2 in Pigure 1 may be connected solely to the link 9, and together therewith movable outwards and inwards, while being laterally guided by surrounding portions of the slide 3. A forward position for the jaw 2 in relation to the slide 3 is shown in outline by full lines in Pigure 1, this being the jaw posi¬ tion corresponding to the shank 14 position illustrated with full lines. It will be further seen from Pigure 4 that the loose link 9 in the toggle mechanism is pivotably connected to the other link 12 in the mechanism by means of a pin 13 going through both plates of the link 9 as well as the link 12. The toggle action in this ease is obtained by the link 12 being the .short arm of a lever with its fulcrum pin 15 rotatably mounted in the slide, its other arm being a pivot- able shank 14.

As will best be seen in Pigure 2, the pivotable shank 14 is made with a passage 16 for a bottom portion 17 of the guid portion ( igures 1 and 3) and/or a second shank 18 (Pigures 1 and 2) connected to the guide portion. In Pigure 1, the shank 18 is implemented as an unscrewed extension of the screw 6. Chain-dotted contours of the shank 14 indicate in Pigure 1 the end positions thereof, which are determined by the toggle mechanism motion in the slide 3, and correspond to the chain-dotted retracted position of the jaw 2. The passage 16 allows the shank 14 to be pivoted past the shank 18, to the right in the Pigure. The shank 14 can thus swing in both directions from its intermediate position,

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corresponding to the dead centre of the toggle. Thus, the jaws may be caused to bite by applying a return movement force on the pivotable shank when it has been swung in either direction. Thus, movement of the jaws to engagement can be provided by applying a force on the shank 1 in either of the directions in which the wrench can be turned.

As will be seen from Pigure 1 and the description above the guide portion 4 merges in this embodiment unarticu- latedly into the shank 18, via the part threaded as the screw 6, with the result that the shank 18 is also a part of the adjusting means for setting the gap of the wrench.

Since both shanks 14 and 18 have their top ends attached to the slide 3, their mutually relative positions are not altered by different gap settings, enabling the shank 14 always to swing past the shank 18, as required.

In all three illustrated embodiments, the pivotable shank 14 is formed as a stirrup, e.g. of sheet metal, for t providing thepassage 16. In all these cases it has its stirrup ends rigidly attached, e.g. by welding, to the pin 15, ^' which is rotatably mounted in the slide 3.

Similar or closely related parts have been given corres ponding reference denotations in all the figures. In Pigures 2 and 3, full lines for the aw 2 illustrate its position with the shank 14 swung out, also indicated by full lines, while a chain-dotted contour line indicates the retracted position of the jaw.

The embodiment illustrated in Pigure 2 differs from the one already described essentially in that the guide portion 4 is rigidly attached to, or integral with a shank 18, and externally threaded for coaction with an adjusting nut 19 which abuts against the slide 3, for limiting the gliding movement thereof and thereby any movement towards a greater jaw gap. The slide 3 is in this case formed to surround the solid guide portion 4, for being glidably guided by it. As in the embodiment illustrated in Pigures 3 and 4, one end of the jaw 2 is here pivotably mounted by a pin 20 in the slide 3. The toggle mechanism is of the same implemen-

tation as described in conjunction with Pigure 4. The shank 14 has sufficient length to afford passage to the shank 18, even when the wrench is adjusted for a very small jaw gap giving maximum extension of the shank 18 relative the shank 14. The adjusting nut 19 will also be accommodated freely in the passage 16 in this embodiment.

The embodiment illustrated in Pigures 3 and 4 relates to a single-shank pipe wrench. Compared with the wrench in Pigure 2, it does-not have the shank 18 and has the adjus - ing nut 19 mounted in a recess in the slide 3. The nut 19 thus prevents relative movement of the guide portion 4 and slide 3, and thus alteration of the set jaw gap in either direction. A spring 21 (Pigure 4) is adapted for holding the unloaded toggle mechanism in an intermediate position (Although Pigure 4 illustrates the toggle mechanism with the shank 14 swung out to the left according to Pig. 3). In this case the passage 16 affords space for the adjust¬ ing nut 19 and a rear portion of the guide portion 4 .

The embodiment according to Pigure 3 can be used for two-shank wrenches as well, if the guide portion in this figure is extended downwards with an unthreaded portion serving as a shank or handle. It is thus also possible to implement this wrench such that it may be marketed option¬ ally convertible from a one-shank to a two-shank version, and vice versa, with the aid of an extension rod which may be threaded directly onto the free bottom end of the guide portion 4.

The embodiment according to Pigure 1 can be converted in a similar manner, in this case from two-shank to one- shank, by the screw 6 being made with a knurled knob (not shown) instead of the shank 18.

In the production of wrenches with the embodiments according to Pigures 3 and 1 , it is conceivable to retain the parts unaltered with the exception of the components just mentioned, and optionally assemble one-shank or two- shank wrenches, with the aid of selection between these com¬ ponents only.

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It is further possible to form the passage 16 other¬ wise than as the opening in a stirrup structure. The pivot¬ able shank 14 thus does not need to constitute a closed stirrup, but may be two parallel shank portions, for example, one on either side of the wrench, or may be only one such shank portion extending downwards along one side of the wrench, round the end of the fixed leg and a dis _^ tanc upwards along the opposite side. Por a one-shank wrench, it can have a similar implementation and be extended downwards by means of a solid handle portion.

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