GB2251568A

GB2251568A - Adjustable spanner

Info

Publication number: GB2251568A
Application number: GB9100747A
Authority: GB
Inventors: John Richard Wills
Original assignee: Individual
Current assignee: Individual
Priority date: 1991-01-14
Filing date: 1991-01-14
Publication date: 1992-07-15
Anticipated expiration: 2011-01-14
Also published as: AU2328592A; GB2251568B; WO1994001248A1; GB9100747D0

Abstract

An adjustable spanner comprises first and second jaw members 2, 3 defining first and second parallel jaw faces 4, 5, the jaw members being slid able relative to each other to adjust the distance between the jaw faces; a first wedge face 8 defined on the first jaw member; a second wedge face 9 defined on the second jaw member; a looking member 10 having wedge faces 11, 12 complementary to the wedge faces of the jaw members, the looking member being slidable relative to the jaw members to bring the wedge faces of the looking member into engagement with the wedge faces of the jaw members to prevent by wedging action the separation of the jaw faces; and resilient means 15 acting between the locking member 10 and the second jaw member 3 to bias the locking member into locking engagement. <IMAGE>

Description

ADJUSTABLE SPANNER This invention relates to an adjustable spanner.

It is known from WO 80/00324 to provide an adjustable wrench based on the principle of friction cleats.

A pair of jaw members having outer edges defining a wedge may be locked in position by means of a locking collar having similar wedge shaped inner surfaces. The jaws may be closed against a spring basis and held at any desired point until the locking collar is loosened and the spring separates the jaws. It is an object of the present invention to provide an improved spanner of similar type.

According to one aspect of the present invention there is provided an adjustable spanner comprising: first and second jaw members defining respectively first and second substantially parallel jaw faces, the jaw members being slidable relative to each other to adjust the distance between the jaw faces; a first wedge face defined on the first jaw member; a second wedge face defined on the second jaw member; a locking member having wedge faces complementary to the wedge faces of the jaw members, the lockiny member being slidable relative to the jaw members to bring the wedge faces of the locking member into engagement with the wedge faces of the jaw members to prevent by wedging action the separation of the jaw faces; and resilient means to bias said jaw faces towards one another and acting between said locking member and one of said first and second jaw members also to bias said locking member into locking engagement.

Preferably said first and second jaw members are slidable about respective mutually contacting plane faces disposed substantially normally to said jaw faces.

The resilient means may comprise a compression spring held in an elongate slot in one of said jaw members, said locking member having a pin or the like passing through or into the slot to compress the spring against an end of the slot.

The preferred embodiment of the invention comprises three mutually slidable members, and the adjustable spanner can be set to any desired size by sliding the jaw members relative to each other to set the desired spacing between the jaw faces, and sliding the locking member or allowing the locking member to slide into engagement with the wedge faces of the jaw members to lock the jaw members against separation of the jaw faces.

In the preferred embodiment of the invention the wedge faces of the jaw members define a small acute angle to each other, and the spanner is adjustable by applying finger pressure to the locking member thereby causing the locking member to move the second jaw member relative to the first jaw member.

A preferred embodiment of the invention will now be more particularly described, by way of example only, reference being had to the accompanying drawings wherein: Figure 1 shows a side elevation of a second jaw member of the spanner; Figure 2 shows a side elevation of a first jaw member of the spanner; Figure 3 shows a side elevation of a locking member of the spanner; Figure 4 shows an end elevation of the locking member of Figure 3; and Figure 5 shows the adjustable spanner in an assembled state.

The adjustable spanner 1 comprises a first jaw member 2 and a second jaw member 3 which define respective substantially parallel jaw faces 4,5. The jaw members 2,3 have respective surfaces 6,7 in sliding engagement whereby the jaw member 3 may be slid along the surface 6 of the jaw member 2 in order to vary the spacing between the jaw faces 4,5.

A first wedge face 8 is provided on the first jaw member, and a second wedge face 9 is provided on the second jaw member. The wedge faces 8,9 define an included angle of 11.250. A locking member 10 has internal wedge faces 11,12 which define substantially the same included angle as the wedge faces 8,9. The locking member 10 can accordingly be positioned as illustrated in Figure 5 with the wedge face 11 in full face engagement with the wedge face 8, and the wedge face 12 in full face engagement with the wedge face 9.

In this position, the jaw members 2,3 are locked against movement in the direction tending to separate the jaw faces 4,5.

The jaw member 3 includes an elongate slot 13 through which passes a pin 14 secured to the locking member 10. A compression spring is installed between an end 15, remote from the jaw face 5, of the slot 13 and the pin 14.

Since the jaw member 3 is locked against outward movement (i.e. in a direction opposite to arrow A), the compression spring, when compressed, biases the pin 14 and thereby the locking member 10 in the direction of arrow A.

Thus jaw faces 4 and 5 are urged together to reduce the spacing between them.

Finger pressure may also be applied to the locking member 10 generally in the direction of the arrow A to cause the jaw member 3 to slide along the surface 6 of the jaw member 2 to reduce the spacing between the jaw faces 4,5.

In order-to separate the jaw faces 4 and 5, finger pressure may be applied to the locking member 10 in a direction opposite to arrow A. This action releases the locking and via pin 14 and compression spring, acting on the end 15 of slot 13, urges the jaw member 3 to slide along surface 6 of the first jaw member 2 so that the jaw faces 4 and 5 separate.

One advantage of the present spanner over the prior art spanners of similar type is that the jaw faces 4 and 5 are biased towards closing together. In prior art spanners, the jaw faces are biased apart, but held in any one position by engagement of the jaw members with a locking member. If the spanner is used to deal with a horizontally extending nut and bolt, there are periods when gravity may act on the locking member causing it to loosen and unlock the jaw members. In this case the spanner may slip on the nut.

Another advantage of spanners embodying the invention is that they are cheaper to manufacture. The first and second jaw members 2 and 3 can be stamped out rather than being machined after production of a blank.

This is because jaw members 2 and 3 are not physically connected directly together as is the case of prior art spanners of this type, and also because slot 13 is open to both faces of the jaw member 3, the spring being retained in the slot by the locking member 10. The pin 14 can be inserted through the locking member 10 once it is in position surrounding the jaw members.

Claims

CLAIMS:

1. An adjustable spanner comprising: first and second jaw members defining respectively first and second substantially parallel jaw faces, the jaw members being slidable relative to each other to adjust the distance between the jaw faces; a first wedge face defined on the first jaw member; a second wedge face defined on the second jaw member; a locking member having wedge faces complementary to the wedge faces of the jaw members, the locking member being slidable relative to the jaw members to bring the wedge faces of the locking member into engagement with the wedge faces of the jaw members to prevent by wedging action the separation of the jaw faces; and resilient means to bias said jaw faces towards one another and acting between said locking member and one of said first and second jaw members to bias said locking member into locking engagement.

2. A spanner according to Claim 1, wherein said first and second jaw members are slidable about respective mutually contacting plane faces disposed substantially normally to said jaw faces.

3. A spanner according to Claim 1 or Claim 2, wherein the resilient means comprise a compression spring held in an elongate slot in one of said jaw members said locking member having a pin or the like passing through or into the slot to compress the spring against an end of the slot.

4. A spanner according to any preceding claim, wherein the jaw members d the locking member comprise three mutually slidable members, and the spanner can be set to any desired size by sliding the jaw members relative to each other to set the desired spacing between the jaw faces, and sliding the locking member or allowing the locking member to slide into engagement with the wedge faces of the jaw members to lock the jaw members against separation of the jaw faces.

5. A spanner according to any preceding claim, wherein the wedge faces of the jaw members define a small acute angle to each other.

6. A spanner according to any preceding claim, wherein the spanner is adjustable by applying finger pressure to the locking member thereby causing the locking member to move the second jaw member relative to the first jaw member.

7. An adjustable spanner substantially as hereinbefore described with reference to the accompanying drawings.