GB2252065A - Spanner - Google Patents

Abstract

A spanner has a head comprising two jaws mounted on a handle, each jaw having an inner face opposed to and parallel to that of the other jaw. One of the jaws is reversibly movable in a direction at a small angle to the inner faces of the jaws so as to alter the gap between the faces, thus allowing free rotation of the spanner from one pair of opposed flats on a nut or bolt past one or more opposed pairs of apexes to another pair of flats. The spanner can thus re-engage the nut or bolt without having to be completely disengaged from the fastener. The movable jaw is preferably biased towards the operating position. <IMAGE>

Description

SPANNER This invention relates to a spanner, and in particular to a spanner for use in restricted areas.

Open-jawed spanners are extremely common and widely used. They have the great advantage of extreme simplicity and strength, providing good leverage.

Models are available with adjustable jaws, one of the two jaws being arranged for movement relative to the other jaw so as to provide a wider or narrower opening, to fit different nuts or bolts. Unlike ring spanners or socket spanners, open-jawed spanners cannot be fitted with a ratchet system to enable the nut to be turned with only limited space for movement of the spanner handle. This means that if an open-jawed spanner is to be used in a restricted area, the head must be disengaged from the nut every time the limit of movement has been reached, and the spanner then re-applied to the nut.

A ratchet mechanism is not possible in the case of open-jawed spanners, since the handle must remain opposite the open end of the jaws. Thus, traditionally, open-jawed spanners have had limited application to areas of restricted access. There is thus a need for a relatively simple open-jawed spanner having jaws which can be easily disengaged from one pair of flats on a nut and then re-engaged on a new pair of flats, without having to remove the spanner head completely from the nut.

This invention is based on the provision of a manually slidable jaw which can move at a slight angle to the axis of the jaw so as to widen the mouth of the spanner sufficiently for it to slip past a pair of apexes and onto the next pair of flats.

According to the present invention there is provided a spanner having a head comprising two open jaws mounted on a handle, each jaw having an inner face opposed to and parallel to that of the other jaw, one jaw being movable relative to the other, characterised in that one of the jaws is reversibly movable in a direction at a slight angle to the inner faces of the jaws1 so as to alter the gap between the said faces, thus allowing free rotation of the spanner from one pair of opposed flats on a nut or bolt past one or more opposed pairs of apexes to another pair of flats and to re-engage the nut or bolt without having to disengage the spanner head completely.

It will be seen that since the inner faces are parallel, as one jaw moves at a slight angle to the faces, the movement causes a small transverse displacement of the jaw with respect to the other jaw, thus widening the gap between them. Preferably, the movement of the jaw should be provided by a small movement of a thumb or finger of the hand gripping the spanner handle. Conveniently, the movable jaw is at the end of a slidable member which can slide in a housing in the main body of the spanner to which the other jaw is attached. Preferably, the slidable member is provided with knurling, or an otherwise roughened surface, to facilitate movement with the thumb.

While it is quite practical for the sliding member to move in either direction with thumb or finger pressure, in a preferred embodiment the slidable member is biased towards the operating position of the jaw, so that the movable jaw can be slid to widen the mouth and thus release the grip on the nut, by pressing downwards with the thumb, but can be restored to its original position by merely removing the thumb pressure.

It is important that the movement of the jaw should be at a relatively small angle to the face of the jaw.

Typically an angle of from 8 to 25 is convenient especially 10 to 20 , e.g. 11 to 15.. It will be understood that, in turning a nut, the main forces on the jaws of a spanner are generally perpendicular to the faces of the jaws. It will thus be seen that the slidable jaw cannot move in a direction which is generally perpendicular to the face of the opposing jaw, since there would then be no resistance to the forces generated when turning the nut. In contrast, the movable jaw cannot slide directly parallel to the faces, since otherwise the mouth of the spanner will not widen. In practice, the range of angles mentioned above provides sufficient widening with an achievable travel of the sliding member, coupled with sufficient strength in the jaws.In practice, a nut having an apex to apex diameter of, say, 24mm has a flat to flat diameter of 2Omm, requiring a widening of at least 4mm to provide free movement. With the angles given above, this can be achieved with a movement of the sliding member of the order of lOmm.

While the faces of the jaws can be at any suitable angle to the axis of the spanner as a whole (i.e. the axis of the handle), it is obviously desirable for working in restricted spaces if the opening is almost directly opposite the handle, rather than perpendicular (as in the case of a wrench). In a particularly preferred embodiment the movement of the moveable jaw is directly in the direction of the axis of the handle and the jaws are offset from this axis by the required small angle.

A preferred embodiment will now be described with reference to the accompanying drawings in which: Figure 1 is a plan view of the top face of the spanner; Figure 2 is an end projection of the jaws of the spanner; Figure 3 is an oblique view of the top face of the main body of the spanner, with a cut-away view of part of the base section; Figure 4 is an oblique view of the top face of the slidable member; and Figure 5 is a partial view of the spanner and a nut in two positions (a) and (b).

The open-jawed spanner A consists of essentially two sections: (i) A slidable member 2, provided at the proximal end (the end carrying the jaws) with a jaw 1 which is movable relative to ii) a fixed jaw 5 which is provided at the proximal end of the main body 4 of the spanner (which acts to provide the handle of the spanner), the slidable member 2 being held within a complementarily shaped housing 3 in the main body 4 of the spanner.

The slidable member and the main body are both typically fashioned from steel. The outer face of the slidable member 2 is provided with a knurled area 6 or some similar roughened surface, to facilitate movement of the said member with the thumb or finger.

Between the distal end of the slidable member 2 and the base of the complementarily shaped housing 3 for the said member is provided a compression spring 7 as shown in Fig. 3. The spring 7 is shaped such that in its relaxed position the inner face 8 of the jaw of the slidable member 2 is opposed to and parallel to the inner face 9 of the fixed jaw 5, i.e. the jaws are in the operating position for the spanner.

As shown in Fig. 1, the opposed faces 8 and 9 of the jaws 1 and 5 are at a small angle Q to the axis of the jaws 10. In a typical embodiment Q is an angle of about 11'.

At the proximal end of the main body 4, the housing 3 is widened so as to form an open area 12 that reaches to the outer edge of the side of the handle 11 opposite the fixed jaw 5. The face 13 of the side of the handle 11 opposite the face 14 of the lower edge of the movable jaw 1 is shaped so as to be complementary to each other. The open area 12 is provided so as to accomodate axial movement of the slidable member 2 on application of thumb or finger pressure on the knurled area 6.

As seen in Fig. 5 (a) and (b), the amount of axial movement x of the slidable member 2 on application of thumb or finger pressure is at least as such that the transverse displacement of the slidable jaw 1 relative to the fixed jaw 5 provides sufficient widening to allow the jaws of the spannner to be released from one pair of flats of a nut or bolt and slip past a pair of opposing apexes and onto the next pair of flats. This axial movement of the slidable member 2 by the downward pressure of a thumb or finger results in compression of the spring 7. Release of the pressure by the thumb or finger results in the spring returning to its relaxed length, so restoring the slidable member 2 to its original position and hence restoring the jaw 1 to its operating position.

Claims (6)

Claims

1. A spanner having a head comprising two open jaws mounted on a handle, each jaw having an inner face opposed to and parallel to that of the other jaw, one jaw being movable relative to the other, characterized in that one of the jaws is reversibly movable in a direction at a small angle to the inner faces of the jaws so as to alter the gap between the said faces, thus allowing free rotation of the spanner from one pair of opposed flats on a nut or bolt past one or more opposed pairs of apexes to another pair of flats and to re-engage the nut or bolt without having to completely disengage the spanner head.

2. A spanner as claimed in claim 1 in which the movable jaw is mounted at the proximal (i.e. jaw-carrying) end of a slidable member which is held within a complementarily shaped housing in a main body of the spanner at the proximal end of which is mounted the fixed jaw.

3. A spanner as claimed in claim 2 in which the slidable member is biased towards the operating position of the jaw.

4. A spanner as claimed in claim 3 in which a spring is provided between the distal end of the slidable member and the base of the complementarily shaped housing, to provide the bias.

5. A spannner as claimed in any of claims 2 to 4 in which an outer face of the slidable member is provided with a knurled or roughened area for application of thumb or finger pressure.

6. A spanner as claimed in any of the preceding claims substantially as described herein with reference to the accompanying drawings.