GB2207383A

GB2207383A - A clamp

Info

Publication number: GB2207383A
Application number: GB08716109A
Authority: GB
Inventors: Raymond Ibbotson
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-07-08
Filing date: 1987-07-08
Publication date: 1989-02-01
Also published as: GB8716109D0

Abstract

A clamp comprising a first supporting member carrying a first jaw member (5) a second supporting member (2) carrying a second jaw member (5) and an elongate connecting member (10) wherein the first supporting member (1) is provided with means (18) for releaseably anchoring it to one end of the connecting member (10) and the second supporting member (2) which is moveably mounted on the opposite end of the connecting member (10) is provided with screw threaded drive means (11, 12, 13) for driving it along the connecting member (10) towards and away from the first supporting member (1) thereby enabling the distance between the first and second jaw members (5) to be adjusted. <IMAGE>

Description

DESCRIPTION A CLAMP The present invention relates to a clamp, and more especially to a clamp comprising a plurality of separate integer parts which are adapted, in use, to be connected together to accommodate a wide range of workpiece sizes1 whilst enabling the clamp to be dismantled and stored compactly.

Vices and bar clamps generally comprise two facing jaws which are moveable relative'to each other so as to grip a workpiece therebetween. Both types of tool are well known and widely used both by craftsmen and by handimen, but are, generally speaking, highly specialised and only suitable for use in a limited number of applications.

Vices are generally used for holding a workpiece whilst it is worked upon and have a limited maximum jaw width, although they are available in a wide range of sizes. In use, they are usually secured to a heavy workbench the weight of which helps to fix the workpiece in position. Unfortunately, the limited maximum jaw width restricts the number of applications for which a vice may be suitable.

Bar clamps essentially comprise a solid elongate steel bar having a first bracket supporting a screw adjusted jaw fixed in position at one end of the bar, and a second bracket supporting a fixed jaw, facing the screw adjusted jaw, which can be slid along the length of the bar and secured in place at any one of a plurality of predetermined positions along the bar, defined by locating holes in the bar, by passing a fixing pin through one of the locating holes. In use, the distance between the jaws is first set approximately to the width of a workpiece by moving the second bracket to the nearest locating hole in the bar corresponding to the required distance, where it is then secured in place with the fixing pin. The jaws of the bar clamp are then tightened onto the workpiece by screw adjusting the position of the screw adjusted jaw.

Bar clamps are available in a wide variety of fixed lengths, anywhere from two to six feet, generally in one foot increments. Of course, it is important that the faces of the jaws remain parallel with each other when tightened onto a workpiece, and the flexibility of the bar is an important factor ensuring this. As the length of a bar clamp increases, so too must the width of the bar to prevent it from flexing. This increases the weight of the bar clamp and makes them comparatively expensive and heavy. Also long bar clamps are awkward to store.

Each length of bar clamp is, generally speaking, only suitable for use with a specific range of workpiece sizes. In other words the largest bar clamp cannot be satisfactorily put to use on a workpiece which irould normally be accommodated in a two foot bar clamp. This is because of the weight of the bar clamp, and also because substantial length of the bar is redundant and overhangs the edges of the workpiece. The outcome of this is that a full range of bar clamp:sizes must be available if any size of workpiece is to be satisfactorily accommodated. This further adds to the expense of bar clamps and to the amount of room required for their storage.

It is an object of the present invention to provide a clamp in which the disadvantages associated with conventional bar clamps, referred to hereinabove, are obviated or, at least, substantially mitigated.

It is a further object of the present invention to provide a clamp which may be secured to a workbench, thereby enabling it to substitute for a vice.

It is yet another object of the present invention to provide a clamp comprising a plurality of separate integer components which are adapted, in use, to be connected together to accommodate a wide range of workpiece sizes, whilst enabling the clamp to be dismantled and stored compactly.

It is still another object of the present invention to provide a clamp which is highly versatile in the number and range of applications to which it can usefully be put.

According to a first aspect of the present invention there is provided a clamp comprising a first supporting member carrying a first jaw member, a second supporting member carrying a second jaw member and connecting means adapted in use to be connected between the first and second supporting members, whereby the connecting means is releaseably secured in position relative to the first supporting member, and is protractable and retractable relative to the second supporting member, thereby enabling the distance between the first and second jaw members to be adjusted.

The connecting means comprises an elongate member which carries a screw threaded portion at one end which co-operatively engages with a matching screw threaded portion carried by the second supporting member. The screw threaded portion carried by the second supporting member is rotatable by means of a lever arm so that the said elongate member is screwed into or out of the second support supporting member, thereby increasing or decreasing the effective combined length of the two members.

The connecting means may further comprise one or more elongate extension bars adapted, in use, to be releaseably connected together, end to end between said first supporting member and the said elongate member. Any number of these elongate extension bars can be used, to give the clamp a required length, yet because they are releaseably secured together it is a simple matter to dismantle the clamp for storage. Preferably, the elongate extension bars are of uniform length.

Conveniently, each of the said elongate extension bars is of box-shaped section which gives it considerable strength and rigidity, without unduly adding to the weight of each one, and a box shaped socket is provided at one end thereof to receive the other end of an adjacent elongate extension bar. The elongate extension bars may be releaseably secured together by means of fixing pins which pass through locating holes in the adjacent ends thereof. Preferably, the first supporting member comprises a tubular box shaped section adapted to receive the box shaped section of each elongate extension bar, and the free end of the elongate member is adapted to be received in the box shaped socket of each elongate extension bar. Fixing pins are used to releaseably secure the free ends of the said one or more elongate extension bars in place.

Preferably, a plurality of equidistantly spaced locating holes are provided along the length of each elongate extension bar, thereby enabling the position of the first support member along each elongate extension bar to be adjusted.

As an alternative to using elongate extension bars the sad connecting means may further comprise one or more lengths of chain, any number of which can be releaseably secured together end to end between the first supporting member and the said elongate member.

The free ends of the said one or more chains are received in slots provided in the first supporting member and the said first elongate bar and are releaseably secured therein by means of fixing pins which pass through the sides of each slot and through a link in the chain. Adjacent lengths of chain may be releaseably secured together by means of a coupling member of substantially box shaped section in which the adjacent ends of two lengths of chain are received. A fixing pin is then passed through locating holes in the sides of the coupling member and through links 'in both lengths of chain.

Where lengths of chain are used in place of the elongate extension bars it is possible to use a plurality of clamps in combination, with one clamp overlapping the other. This is particularly useful where the workpiece comprises a plurality of corner sections which must be held together whilst, say, an adhesive sets. Overlapping the clamps ensures that the clamping forces are uniformly distributed around the workpiece and reduces any possibility of the workpiece distorting. This technique may also be applied using both conventional bar clamps and a clamp in accordance with the present invention using elongate extension bars, but is not as effective because the upper-most bars are not along their length supported against the surface of the workpiece.

Preferably, the first and second jaw members are detachably secured to the first and second supporting members. Conveniently, this is achieved by providing a plug on the rear surface of each jaw member and a correspondingly shaped socket on the upper surface of each supporting member.

Advantageously, the clamp of the present invention provides a plurality of interchangeable jaw members of various shapes and sizes according to the size of the workpiece and the specific application for which the clamp is intended to be used. For example, each jaw member may comprise a simple planar face, or corner shaped face, or an elongate bar. With the latter two types of jaw member in particular it may be advantageous to have these pivotably connected to the plug which releaseably secures each to a respective supporting member. This allows the position each jaw member assumes relative to the connecting means to be adjusted to accommodate any size of workpiece therebetween.

Preferably, at least one of the elongate extension bars is adapted in use to be inserted into the socket carried by each supporting member and the jaw member itself is releaseably secured to the and of the extension bar in the box shaped socket. In this way, the jaw members can be positioned so that they will actually close together.

Preferably, one or both of the supporting members, or the first supporting member and the said first elongate bar comprises a screw plate which enables it to be screwed to a work surface, thereby enabling the clamp to function after the fashion of a vice.

According to a second aspect of the present invention there is provided an adjustable tie for securing together bundles of loose items such as sticks of wood comprising a pair of relatively adjustable members and a flexible tie secured at each end to a respective one of the two members.

As the relatively adjustable members are moved closer the ends of the tie are brought closer together thereby tightening the tie around a bundle of loose items held therebetween.

Conveniently, the relatively adjustable members comprise the said second supporting member and the said first elongate bar in combination and the tie comprises one or more lengths of chain, connected together end to end. A slot is provided in the second supporting member in which the free end of the chain is received and it is releaseably secured in ppsition by means of a fixing pin which passes through locating holes in the side of the slot and through one of the links in the chain.

Embodiments of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 shows an exploded view of a clamp according to the first aspect of the present invention; Fig. 2 shows a detailed plan view of the second supporting member and the first elongate bar of Fig. 1 with a part of the second supporting member cut away to show the screw threaded adjustment mechanism; and Fig. 3 shows an exploded view of the adjustable tie according to the second aspect of the present invention.

Referring to Figs. t and 2 of the present invention the clamp comprises a first supporting member I and a second supporting member 2, both of which comprise an elongate tubular box shaped section 3 and, above it, a box shaped socket 4. Each box shaped socket 4 is adapted in use to releaseably receive therein a correspandingly shaped plug 5 which forms part of a jaw member 6. In the drawings three different types of jaw member 6 are shown, these each being interchangeable according to the particular application for which the clamp is intended to be used. Jaw member 6a comprises a simple vertical planar face 7 and is intended for use in similar applications to a conventional bar clamp. Jaw member 6b comprises a corner shaped face 8 and is intended for use in holding together corner sections of a workpiece.

It is pivotally connected to the plug portion 5 so as to enable it to assume differing positions relative to the supporting member 1 or 2, and thereby allows the camp to be angled across opposite sides of a workpiece. Jaw member 6c comprises an elongate bar 9 which is also pivotally connected to the plug portion 5 and thereby allows the clamp to be used across workpieces having opposite sides which are not necessarily parallel to one another.

Within the elongate tubular box shaped section 3 of the second supporting member 2 there is contained an elongate bar 10. The bar 10 is slideable in and out of the tubular box shaped section 3 and its position within the section 3 is adjustable by means of a screw threaded rod 11, one end of which co-operatively engages with a matching screw threaded hole in the inner end 12 of the bar 10 and the other end of which is fixed to a lever arm 13 outside the section 3. It will be readily appreciated that as the lever arm 13 is turned the rod 11 is rotated and screws into or out of the screw threaded hole in the inner end 12 of the bar 10, thereby screwing the bar 10 into or out of the section 3 and reducing or increasing the distance of the jaw member 6 located in socket 4 from the outer end 14 of the bar 10.

Between the outer end 14 of the bar 10 and the elongate tubular box shaped section 3 of the first supporting member 1 is provided at least one elongate extension bar 15. Each elongate extension bar 15 comprises an elongate box shaped section 16 having a plurality of equidistantly spaced locating holes 17 along its length and at one end a box shaped socket 18.

Adjacent extension bars 15 are connected together end to end by inserting the box shaped section 16 of one extension bar 15 into the box shaped socket 18 of another and releaseably securing them in place by means of a fastening pin 19 which passes through locating holes 20 in the adjacent ends thereof. The free box shaped socket 18 at the end of one or more interconnected extension bars 15 is releaseably secured to the outer end 14 of the elongate bar 10, also by means of a fastening pin 19.The other free end of one or more interconnected extension bars 15 is slideably received within the elongate tubular box shaped section 3 of the first supporting member 1 where it too is releaseably secured in place by means of- a fastening pin 19 which passes through a locating hole 21 in the sides of the section 3 and through one of the locating holes 17 or 20 in the elongate box shaped section 16 itself.

It will be readily apparent that the clamp described with reference to Figs. 1 and 2 of the accompanying drawings works in much the same way as a conventional bar clamp, in as much as a workpiece is placed between the facing jaw members 6 and the first supporting member 1 is moved along the end extension bar 15 until the distance between the jaw members 6 roughly corresponds to the width of the workpiece, where it is then secured in place using a fixing pin 19 passed through the locating holes.

Final adjustment of the clamp is then achieved by turning the lever arm 13 to draw the extension bars 15, the first supporting member 1 and the jaw member 6 carried thereby towards the second supporting member 2 and the jaw member 6 carried thereby, closing the distance between the jaw members 6. However, the length of the clamp of the present invention can be readily increased or decreased simply by adding in or taking out further extension bars 15, in marked contrast to a conventional bar clamp where the length is fixed. Furthermore, the clamp can be v easily disassembled for storage simply by removing the fixing pins 19 holding everything together.

Of course, it is possible to connect the elongate bar 10 directly to the first supporting member 1, without using any elongate extension bars 15 therebetween. This further reduces the minimum size of the clamp which can be very useful with small workpieces.

It is also possible to insert one or more interconnected extension bars 15 between the box shaped socket 4, carried by one of the supporting members 1 or 2, and the associated jaw member 6. As will be readily apparent this considerably reduces the distance between the jaws 6 to a point where this may even be closed completely.

The first supporting member 1 and the elongate bar 10 both have a screw plate 22 provided on the bottom surface thereof. These screw plates 22 allow the first supporting member 1 and the elongate bar 10 to be secured to the top of a workbench. In this position the second supporting member 2 is still adjustable relative to the elongate bar 10 and hence, the first supporting member so that a fixed vice is formed by the two jaw members 6 carried thereby.

The elongate extension bars 15 may be substituted for lengths of chain (not shown) which are also connected together end to end between the first supporting member 1 and the elongate bar 10. Adjacent chain ends are connected together by means of a chain coupling device, as shown in Fig. 3 which comprises a tubular section 23 into which the ends of two lengths of chain can be inserted and releaseably secured in place by means of a fastening pin 19 which passes through locating holes 24 and through the end links of both chains. The free ends of the chain are received in a slot 25 in the end of the elongate bar 10 and in the tubular section 3 of the first supporting member 1 and both ends are releaseably secured in place by means of fastening pins 19.

The chains provide a flexible, as opposed to rigid clamp, which is particularly useful where a number of clamps are to be used in combination and are required to overlap each other, as in a workpiece comprising a plurality of corner sections. However, apart from this the operation of a flexible chain clamp embodying the first aspect of the present invention is essentially the same as that of a rigid extension bar clamp embodying the first aspect of the present invention.

Referring now to Fig. 3 of the accompanying drawings there is shown an adjustable tie for securing together bundles of loose items, such as sticks of wood. This may be necessary for ease of storage or handling. The adjustable tie essentially comprises the second supporting member 2 and the elongate bar 10 in combination and the tie comprises one or more lengths of chain 26 which is secured at each end to the member 2 and the bar 10 respectively by means of fastening pins 19.

In use, as the member 2 and the bar 10 are moved towards each other by the screw threaded adjustment mechanism (described in detail with reference to Figs. 1 and 2) the ends of the chain 26 are also brought closer together, thereby causing the chain 26 to grip any bundle of items contained therebetween.

Claims

1. A clamp comprising a first supporting member carrying a first jaw member, a second supporting member carrying a second jaw member and an elongate connecting member, wherein the first supporting member is provided with means for releaseably anchoring it to one end of the connecting member and the second supporting member1 which is moveably mounted on the opposite end of the connecting member, is provided with screw threaded drive means for driving it along the connecting member towards and away from the first supporting member, thereby enabling the distance between the first and second jaw members to be adjusted.

2. A clamp according to claim 1, wherein the screw threaded drive comprises an elongate externally screw threaded member-carried by the second supporting member which screw threadedly engages in an internally screw threaded member carried by the connecting member.

3. A clamp according to claim 2 wherein the elongate externally screw threaded member is rotated about its axis by means of a lever arm.

4. A clamp according to claim 1, 2 or 3, comprising one or more elongate extension members adapted, in use, to be connected end to end between the first supporting member and the connecting member.

5. A clamp according to claim 4, wherein the elongate extension members are comprised of extension bars, each of which comprises a socket at one end thereof to receive the other end of an adjacent extension bar or the end of the connecting member.

6. A clamp according to claim 5, wherein the first supporting member is slideable along the or each extension bar and the means for releaseably securing it to the connecting member also enable it to be releaseably anchored at predetermined positions along the or each extension bar.

8. A clamp according to claim 4, wherein the elongate extension members comprise one or more lengths of chain.

9. A clamp according to claim 8, wherein a slot is provided in the first supporting member and in the connecting member to receive the chain and means are provided for securing the chain in each slot.

10. A clamp according to claim 9,wherein the securement means comprises a fixing pin which is passed through locating holes in the sides of the slot and through a link in the chain.

11. A clamp according to any preceding claim, wherein each jaw member is detachably secured to its supporting member.

12. A clamp according to claim 11, wherein each support member comprises a socket into which a pin carried by the jaw member engages, or vice versa.

13. A clamp according to claim 11 or 12, wherein an extension bar can be connected between each jaw member and its supporting member, thereby decreasing the distance between the two jaw members, whilst maintaining the same distance between the support members.

14. A clamp according to any preceding claim, comprising means whereby the first and second support members can be secured to a work surface.

15. An adjustable tie comprising a pair of relatively adjustable members and a band, chain or rope secured at each end to a respective one of the two members.

16. A clamp substantially as hereinbefore described with reference to Figs. 1 and 2 of the accompanying drawings.

17. An adjustable tie substantially as hereinbefore described with reference to Fig. 3 of the accompanying drawings.