GB2272096A - Improvements in and relating to clamps - Google Patents

Abstract

In the field of signposts and signboards, there is a need for a readily adjustable and dismantleable sign post system which is aesthetically pleasing. The disclosure relates to a clamp (15) for a signpost (10), the clamp comprising a first clamp member (16), a second clamp member (17) rigidly secured thereto; a third clamp member (18) moveable in the space between the first and second clamp members and a fourth clamp member (19) moveable externally of the first and second members. The third and fourth clamp members (18, 19) are rigidly secured together, and the four clamp members are retained captive relative to one another thereby to create two pairs of simultaneously operable clamp jaws. A bolt (26) passing centrally through the four clamp members may be screwed to a reaction surface formed by, e.g., a support post(12) and tightening of the bolt (26) causes tightening of the clamping jaws. The clamp members may include a number of mutually aligned recesses or apertures (33) for clampingly receiving a portion (38) of a signboard. The clamps may be secured to two support posts so that one or more signboards may be held between the posts (Figure 3). <IMAGE>

Description

Improvements In and Relating to Clamps This invention relates to a clamp, in particular but not exclusively for a signboard. The invention also relates to a signpost incorporating such a clamp, and to a signboard suitable for use with such a clamp.

There is a need for low-cost yet aesthetically pleasing signposting for example, in parks, on industrial estates and on university campuses, as well as in numerous other places. Various arrangements of signpost have previously been devised, but very few of these allow for easy replacement of the signboards which they support. Replacement of the signboards is frequently necessary in, e.g., industrial parks, on university campuses, on hospital sites, in amusement parks, on factory sites, in shopping precincts and department stores and in office suites where the tenants may change from time to time, departments may be moved and construction work may alter the layout.

Previous signposts have been difficult if not impossible to dismantle and alter, and such signposts do not generally allow the easy and neat mounting of several signboards pointing in different directions on a single post.

In the simplest form of the invention, there is provided a clamp for securing, e.g., a signboard in a signpost, the clamp comprising a first clamp member; a further clamp member spaced from the first clamp member, the clamp members being constrained to move relative to one another between an initial configuration and a further configuration closer to one another; means for selectively moving the clamp members relative to one another, thereby selectively to open and close the clamp for clamping one or more parts of a signboard; and means for securing the clamps in e.g. a signpost.

According to a second aspect of the invention, there is provided a clamp for, e.g., a signboard, comprising a first elongate clamp member; a second clamp member spaced from and secured to the first clamp member; a third clamp member moveable relative to the first clamp member; a fourth clamp member secured to the third clamp member, the third clamp member being constrained to move in the space between the first and second clamp members between an initial position spaced from the first clamp member and a further position closer thereto, and the fourth clamp member being constrained to move between an initial position spaced from the second clamp member and a further position closer thereto such that relative movement between the first and third clamp members causes relative movement between the second and fourth clamp members; and means for selectively moving said first and third clamp members one relative to the other and/or said second and fourth clamp members one relative to the other, thereby selectively to open and close the clamp for clamping one or more parts of e.-g. a signboard.

An advantage of this clamp is that the use of pairs of opposed clamp members (i.e. the first and third clamp members and the second and fourth clamp members respectively) permits the secure fastening of signboards pointing in a number of directions about the clamp.

Preferably, the first and third clamp members comprise respective, generally concentric plates. Conveniently, opposed surfaces of the first and second clamp members have respectively formed therein at least one pair of mutually aligned recesses or apertures for clampingly receiving a portion of, e.g, a signboard. In a particularly preferred embodiment, the opposed surfaces have formed therein a plurality of angularly spaced such recesses or apertures.

These optional features enable the clamp to be particularly suited to the securing of signboards.

Conveniently, the second and fourth clamp members comprise respective, generally concentric plates. It is preferable that opposed surfaces of the second and fourth clamp members have respectively formed therein at least one pair of mutually aligned recesses or apertures for clampingly receiving a portion of, e.g., a signboard. In a particularly preferred embodiment of the invention, the opposed surfaces have formed therein a plurality of angularly spaced such recesses or apertures.

These optional features confer similar advantages in relation to the second and fourth clamp members.

Conveniently, the four clamp members are concentric. This feature facilitates the manufacture of a clamp in accordance with the invention.

In a preferred embodiment, the means for selectively moving the clamp members comprises a bolt engageable with one of said first and second clamp members and securable to a reaction member engageable with one of the third and fourth clamp members, the position of securing of the reaction member on the bolt being selectively adjustable thereby to open and close the clamp.

In a specific embodiment of the invention described below, the reaction member is constituted by a part of a signpost to which the clamp is securable.

Preferably, the clamp members each include a respective, mutually aligned aperture, the bolt passing through the apertures and having a head engageable with the first clamp member and a threaded portion for engaging a portion of a reaction member complementary thereto, the reaction member being arranged to engage the fourth member.

Preferably, when the bolt is secured to the reaction member, the bolt is spring biassed to tend to close the clamp.

These features prevent the components of the clamp from working loose when the bolt is screwed to a reaction member.

Conveniently, the second and third clamp members each have a least one through-going aperture formed therein, the first and second clamp members being rigidly interconnected by a rod passing through an aperture in the third clamp member, and the third and fourth clamp members being rigidly interconnected by a rod passing through an aperture in the second clamp member.

Thus, the clamp members are retained loosely captive with respect to one another. This enables the clamp to be advantageously compact, and the risk of separation of the components when the clamp is dismantled is reduced.

In a preferred embodiment, the third clamp member has a plurality of through-going apertures formed therein and the first and second members are rigidly interconnected by a plurality of rods passing through respective apertures in the third clamp member.

This makes correct alignment of the opposed first and third clamp members inevitable e.g. on closing of the clamp if the positions of the rods and apertures are carefully chosen.

Conveniently, the second clamp member has a plurality of through-going apertures formed therein and the third and fourth clamp members are rigidly interconnected by a plurality of rods passing through respective apertures in the second clamp member. Thus, correct alignment of the opposed second and fourth clamp members is inevitable if the portions of the rods and apertures are carefully chosen.

Preferably, the clamp members are constituted by generally circular plates of generally the same diameter as one another. This feature allows signboards easily to be clamped in a plurality of angular locations.

Conveniently, the peripheral portions of opposed surfaces of the clamp members are angled away from one another. This allows the clamp members to be used with a particular kind of signboard, described below.

Conveniently, the clamp assembly may optionally comprise a plurality of clamp members in excess of four wherein the (n-2)th clamp member is constrained to move in the space between the (n-l)th clamp member and the nth clamp member between an initial position spaced from the (n-l)th clamp member and a further position closer thereto: and the nth clamp member is constrained to move between an initial position spaced from the (n-2)th clamp member and a further position closer thereto, the arrangement being such that movement of the moveable clamp members occurs simultaneously.

Thus, the clamp may include a plurality of pairs of opposed clamp members, thereby providing a corresponding plurality of jaws in which, e.g., signboards may be clamped.

According to a third aspect of the invention, there is provided a signpost comprising a clamp as defined hereinabove; a post to which said clamp is securable; and a signboard securable in said clamp.

Conveniently, the signpost may include a plurality of signboards securable to said clamp.

In a preferred embodiment of the invention, the signpost includes a pair of clamps according to the invention as defined hereinabove; a pair of mutually spaced posts to which the respective clamps are securable; and at least one signboard securable in and interconnecting the respective clamps.

In preferred embodiments of the invention, the signposts may comprise a plurality of clamps in excess of two, a corresponding plurality of posts to which the respective clamps are securable and a plurality of signboards respectively securable in the clamps so as to interconnect pairs thereof.

According to a fourth aspect of the invention, there is provided a signboard adapted for clamping in a clamp according to the invention as defined hereinabove, and adapted to form part of a signpost according to the invention as defined hereinabove, the signboard comprising a first surface adapted to carry or convey information; one or more further surfaces generally perpendicular to said first surface; and a pair of mutually spaced projections extending from the further surface or surfaces beyond the boundary of the first surface, the projections being adapted for securing respectively between opposed clamp members of a clamp according to the invention as defined herein above.

Conveniently, a or the further surfaces comprises a folded over portion of the first surface. The further surface may instead optionally consist of an edge of a panel constituting the first surface. Alternatively, the first surface may be a face of a hollow panel having an open side wall, and the or each further surface may be constituted by an insert secured in the open side wall.

Conveniently, the signboard may include a plurality of projections in excess of two extending from one or more further surfaces of the signboard, each projection being adapted for securing between a pair of clamp members of a clamp according to the invention as defined hereinabove.

In preferred embodiments of the invention, the or each projection may comprise a first member adapted for rigid securing to a or the further surface of the signboard, a bifurcated member secured to the first member, the bifurcated member and optionally the first member extending beyond the signboard when the first member is secured as aforesaid; and a pair of spheroidal members respectively secured to the limbs of the bifurcated member, the spheroidal members being suitable for securing between opposed clamp members of a clamp according to the invention as defined herein above.

Preferably, the spheroidal members are resiliently deformable.

There now follows a description of preferred embodiments of the invention, by way of example, with reference being made to the accompanying drawings in which: Figures 1 and la are perspective views of a simple form of signpost made in accordance with the invention and incorporating a clamp made in accordance with the invention; Figure 2 is a perspective view of a more complicated signpost incorporating a clamp made in accordance with the invention; Figures 3 and 4 are perspective views of a third embodiment of the invention; and Figures 5a to 5c are end, plan and side elevational views of a typical bifurcated member forming part of a signboard according to the invention.

Referring to the drawings, and firstly to Figure 1, there is shown a simplified form of signpost 10 according to the invention. Signpost 10 comprises a signboard 11 which in the embodiment of Figure 1 is a pointer-type signboard; a support post 12 and a clamp 15 which is used to secure the signboard 11 to the post 12 in an easily dismantleable and adjustable manner.

Clamp 15 comprises four clamp members, 16, 17, 18 and 19. Each clamp member is in the embodiment shown a disc. The discs are concentric and are each of the same diameter. The discs are arranged one above the other, with the first disc 16 uppermost, the third disc 18 immediately below the first disc, the second disc 17 immediately below the third disc and the fourth disc 19 lowermost.

An outer peripheral portion 16a, 17a, 18a, 19a of each disc is dished with respect to a central, flat portion 16b, 17b, 18b, 19b.

The dished portions 16a, 18a of the respective first and third discs diverge from one another.

Similarly, the dished portions 17a, 19a of the respective second and fourth discs diverge from one another. (Thus, the dished portions of the adjacent second and third discs 17, 18 are directed towards one another; however, this feature is not made use of in the embodiment of Figure 1.) The first disc 16 and second disc 17 are rigidly secured together by means of three rigid rods 21 which interconnect the flat (i.e. undished), circular, central portions 16b, 17b of the respective first and second discs.

The rods 21 are equiangularly spaced about the peripheries of the undished portions 16b, 17b and extend parallel to one another in a vertical direction when the signpost is arranged as shown in Figure 1. The rods 21 may be secured to the undished portion 16b, 17b by any suitable means such as welding; or the casting of the rods 21 in two parts, with one part respectively being formed integrally with one or other of the discs 16, 17, the two rods being rigidly secured together at their juncture.

The rods 21 pass freely through through-going apertures 22 formed in the periphery of undished portion 18b of third disc 18. The apertures 22 are aligned with the respective rods 21 so that third disc 18 is freely moveable in the vertical direction as shown between the first disc 16 and the second disc 17, but cannot move appreciably in any other direction.

Third disc 18 is rigidly connected to fourth disc 19 by means of a plurality of rods 23 which interconnect the peripheries of the undished portion 18b, 19b of the respective third and fourth discs 18, 19 in a similar manner to that in which rods 21 interconnect the discs 16, 17. Each rod 23 passes through an aperture 22 in second disc 17. The rods 23 are equiangularly spaced about the peripheries of the respective undished portion 18b, 19b, and are so arranged as not to coincide with the rods 21.

It will thus be apparent that the discs 18, 19 are moveable together as a pair relative to the pair of discs 16, 17. The disc 18 is moveable in the space between discs 16, 17, and the disc 19 is moveable externally of the pair of discs 16, 17. It will also be apparent that if, for example, fourth disc 19 is caused to move closer to or away from second disc 17, third disc 18 will automatically be caused to move similarly in relation to first disc 16, by virtue of the rigid interconnections of the discs in pairs.

Each disc 16, 17, 18, 19 includes a central, circular aperture 24. The four apertures 24 are mutually aligned.

A bolt 26 having a threaded end portion 27 can be passed through he aligned apertures 24 to protrude on the lower side of disc 19. It will be appreciated that if the threaded portion 27 of bolt 26 is screwed into a complementarily threaded bore in a surface or reaction member, tightening of bolt 26 will cause an upward force to be applied to the lower side of disc 19, thereby driving discs 17 and 19 closer together and hence driving discs 17 and 18 closer together. The upper end of bolt 26 as shown includes a washer 28 and a compression spring 29 encircling the shaft of bolt 26 below the head 31 thereof. The spring 29 is disposed in the space between the washer 28 and the head 31. This arrangement provides a slightly spring-loaded, upper reaction surface which engages the undished portion 16b of disc 16 on tightening of bolt 31, thereby to provide the upward force on fourth disc 19.

In the embodiments shown, the upper surface of head 31 includes a pair of bores 32 adapted for receiving the prongs of a tightening tool whereby bolt 26 can be tightened and loosened. However, it will be appreciated that other designs of head may be employed.

Thus, the ability selectively to move the discs of the clamp 15 closer to and away from one another causes the discs to act as pairs of clamp jaws, the first pair being constituted by discs 16 and 18 and the second pair being constituted by the discs 17 and 19. If the lengths of the rods 21 are the same as those of the rods 23, the spacing between the discs 16 and 18 will always be the same as the spacing between the rods 17 and 19, regardless of the extent to which bolt 26 is tightened.

In a practical embodiment of the invention, as shown in Figure 1, the reaction surface referred to above is constituted by the upper end of support post 12. The upper end of support post 12 includes a bore (not shown) which is threaded in a complementary manner to thread 27 of bolt 26. Thus, clamp 15 is securable to support post 12 by means of bolt 26 which also serves as a means for selectively moving the first and third clamp members one relative to the other and the second and fourth clamp members one relative to the other, thereby selectively to open and close the clamp.

The dished portions 16a, 17a, 18a and 19a of the respective discs are each formed with an annular series of through-going apertures 33. In the embodiment shown, each aperture 33 in disc 16 is aligned with a corresponding aperture 33- in each of the other three discs 17, 18, 19. The apertures are adapted clampingly to receive pairs of projections 34 extending rearwardly from a signboard to be clamped, such as signboard 11.

Each projection 34 includes a bifurcated member 36. The limbs of each bifurcated member 36 terminate in a retaining ring 37 which securely retains a rubberised ball 38.

The sizes of the bifurcated members 36, and the spacings and sizes of the balls 38 are such that each pair of balls 38 can readily be received in upper and lower pairs of adjacent apertures 33 in adjacent pairs of the discs 16, 17, 18, 19. The spacing of the projections 34 on the rear of signboard 11 from one another are such that, in the embodiment of Figure 1, the balls 38 secured to the upper projection 34 are receivable in the recesses in the first disc 16 and the third disc 18, and the balls 38 secured to the lower projection 34 are receivable in the apertures formed in the second disc 17 and the fourth disc 19. When the bolt 26 is loosened and the respective pairs 16, 18 and 17, 19 of discs are allowed to separate from one another, the respective pairs of balls 38 can be inserted into the spaces between the respective jaws of the clamp 15.On tightening of the bolt 26, two of the apertures 33 encircle each ball 38, and on continued tightening on bolt 26 the balls 38, and hence the signboard 11, are tightly secured in the clamp whilst clamp 15 is itself increasingly rigidly secured to support post 12.

Since there is provided a series of apertures 33 about a circumference of each disc 16, 17, 18, 19, the signboard 11 may be secured pointing in any of a number of directions. Additionally, the clamp 15 is suitable for securing a plurality of such signboards 11 to a single post.

In the embodiment of Figure 1, each projection 34 is secured to a surface 39 which is generally perpendicular to the information conveying surface 41 of the signboard. Surface 39 as shown is formed by folding an end portion of surface 41. However, it will be appreciated that numerous other techniques can be employed to form surface 39. for instance, if the thickness of signboard 11 is adequate, it can be formed as a hollow board having an open rear end. A suitable insert can then be secured (e.g. by friction, or an adhesive) in the open end of signboard 11. Alternatively, each projection 37 may be formed with a threaded portion at its forward end, and complementary threaded bores may be formed in the rear end surface of signboard 11.

Figure la is a simplified view of the embodiment of Figure 1, by means of which the relative positions of the six rods 21, 23 may be more clearly seen. In particular, it is clear in Figure la that the three rods 21 interconnect the first and second clamp members, and that the three rods 23 interconnect the second and fourth clamp members.

Referring now to Figure 2, there is shown a second embodiment of the invention. In this embodiment, clamp 15 is formed with eight clamp members.

Alternate clamp members are rigidly secured together by rods with the rods passing through apertures similar to apertures 22 and 24 of Figure 1 formed in the intermediate clamp members. The intermediate clamp members are also rigidly secured together, thereby creating a clamp 15 which is twice the size of that shown in Figure 1. Clamp 15 of Figure 2 has four pairs of jaws, which by virtue of the interconnection of the various components are adjustable simultaneously, and which are always open or closed) to the same degree as one another.

Each clamp member of Figure 2 is formed as a disc such as discs 16 to 19 of Figure 1. Accordingly, the signpost of Figure 2 may readily accommodate signboards 11 at any of three heights (i.e. the uppermost height of clamping is attained by securing the projections 34 of a board 11 between the uppermost pair of clamping jaws; the intermediate height by securing the projections between the second and third lowermost pairs of jaws; and the lowermost height by securing the projections 34 between the lowermost two pairs of clamping jaws).

In the embodiment of Figure 2, the head assembly of bolt 26 is augmented by a top cap 42 which has a downwardly extending side wall and a recessed underside. Each of the six rods interconnecting the various clamping members extends upwardly of the upper surface of the uppermost clamping member, and top cap 42 fits over the free upper ends of the rods. Cap 42 includes a central aperture aligned with the central apertures of the clamping members, and the head of bolt 26 (not visible in Figure 2) bears downwardly on the upper surface of cap 42 on tightening into the support post 12 of Figure 2.

Thus, cap 42 is an alternative means by which the force generated by tightening of bolt 26 into the reaction surface formed at the upper end of post 22 may be transmitted to the clamp members of the clamp 15.

Figures 3 and 4 show a third embodiment of the invention, in which clamp 15 is constituted by sixteen clamp members connected in an extended version of clamp 15 of Figure 1. It will be appreciated that this embodiment of the invention has great versatility because large signboards such as the signboards lla, llb of Figures 3 and 4 having more than two appropriately spaced projections 34 can be securely clamped, with the balls 38 of the respective projections being gripped between the several clamping jaws constituting clamp 15.

The embodiment of Figures 3 and 4 differs from those of Figures 1 and 2 in that a pair of support posts 12 is provided. The signboards lla, 11b include projections 34 extending from each end thereof. The signboards lla, 11b are therefore clampable interconnecting the two clamps 15 atop the respective signposts 12, to create an information board (as opposed to a pointer-type signpost).

Figure 4 shows one method of supporting the support posts 12, namely the provision of a circular foot 43 secured to the lowermost end of each post 12.

The diameter of each foot 43 is such as to provide for stable support of the composite signboard. In the embodiments shown, bores are formed in each foot 43 to mirror the appearance of the clamp discs, thereby providing an attractive appearance of the signboard. However, numerous other methods of securing the signpost or signboard to the floor or ground are possible. For instance, anchor means to which the support posts 12 may be secured can be buried in the ground on which the signpost is to stand; alternatively, brackets or plates may be secured to a floor. Numerous other arrangements are possible.

Referring to Figures 5a to 5c, there are shown three views of a typical projection 34 for use in supporting a signboard according to the invention.

It will be seen that the bifurcated portion 36 of the projection 34 resembles the shape of a key for a clockwork motor. The retaining rings 37 are formed integrally with the limbs of the bifurcated portion 36. Since each ball 38 is made of rubber or a similar material, or at least is coated with such a material, it is resiliently deformable and may therefore be squeezed into a retaining relationship with the retaining ring 37. Each ball 38 is preferably formed with a circumferential groove into which the inner edge of the appropriate retaining ring 37 is received when the ball 38 is pushed on assembly of the projection 34 into its operative position as shown in Figures 5b and 5c.

The resilience of each ball 38 also is of benefit during tightening of the clamps 15 according to the invention. The resilience allows for backlash in the components to be accommodated on tightening of the clamps 15. The spring-loading (if present) of the head 31 of bolt 26 also assists in eliminating the effects of backlash in the components.

It will be appreciated that the clamp, signpost and signboards of the invention constitute a versatile and attractive system by means of which information and directions may be given. The signboards may be secured in any of a number of angular positions about the signpost 12. It is easy to loosen the clamps 15 thereby to dismantle the signposts and/or change the positions and kinds of signboards 11. When the support posts 12 are secured to feet such as feet 43 of Figure 4, the signposts may readily be moved from place to place as desired.

Whilst the clamp 15 has been described as including circular clamp members, other shapes of clamp member (e.g., square, triangular, rectangular, etc.) may readily be employed. Furthermore, it is not regarded as essential that the clamp members include a dished portion, nor is it essential that the clamp members include through-going apertures such as apertures 33 of Figure 1. The apertures may be replaced by recesses which do not pass all the way through the clamp members, and may even be dispensed with entirely under certain circumstances.

There is no theoretical limit to the number of clamp members which may be secured together in the manner described to form a clamp 15. Thus, clamp members 15 of virtually any length can be constructed.

In practice, however, there will be limits on the lengths of clamp members 15 which can be constructed without the stability of the signposts being adversely affected. Of course, it is possible to enlarge the size of any support foot 43, or to strengthen any other support arrangement for the support post 12, to accommodate exceptionally long clamps 15. However, under such circumstances some of the advantages of, e.g, the light weight and aesthetic attractiveness of the system may be lost.

Claims (32)

1. A clamp for securing, e.g., a signboard in a signpost, the clamp comprising a first clamp member; a further clamp member spaced from the first clamp member, the clamp members being constrained to move relative to one another between an initial configuration and a further configuration closer to one another; means for selectively moving the clamp members relative to one another, thereby selectively to open and close the clamp for clamping one or more parts of a signboard; and means for securing the clamps in e.g. a signpost.

2. A clamp for, e.g. a signboard, comprising a first clamp member; a second clamp member spaced from and secured to the first clamp member; a third clamp member moveable relative to the first clamp member; a fourth clamp member secured to and spaced from the third clamp member, the third clamp member being constrained to move in the space between the first and second clamp members between an initial position spaced from the first clamp member and a further position closer thereto, and the fourth clamp member being constrained to move between an initial position spaced from the second clamp member and a further position closer thereto such that relative movement between the first and third clamp members causes relative movement between the second and fourth clamp members; and means for selectively moving said first and third clamp members one relative to the other and/or said second and fourth clamp members one relative to the other, thereby selectively to open and close the clamp for clamping one or more parts of e.g. a signboard.

3. A clamp according to Claim 2 wherein the first and third clamp members comprise respective, generally concentric plates.

4. A clamp according to Claim 3 wherein opposed surfaces of the first and second clamp members have respectively formed therein at least one pair of mutually aligned recesses or apertures for clampingly receiving a portion of, e.g., a signboard.

5. A clamp according to Claim 4 wherein the opposed surfaces have formed therein a plurality of angularly spaced such recesses or apertures.

6. A clamp according to any of Claims 2 to 5 wherein the second and fourth clamp members comprise respective, generally concentric plates.

7. A clamp according to Claim 6 wherein opposed surfaces of the second and fourth clamp members have respectively formed therein at least one pair of mutually aligned recesses or apertures for clampingly receiving a portion of, e.g., a signboard.

8. A clamp according to Claim 7 wherein the opposed surfaces have formed therein a plurality of angularly spaced such recesses or apertures.

9. A clamp according to Claim 3 and Claim 6 wherein the four clamp members are concentric.

10. A clamp according to any Claims 2 to 9 wherein the means for selectively moving the clamp members comprises a bolt engageable with one of said first and second clamp members and securable to a reaction member engageable with one of the third and fourth clamp members, the position of securing of the reaction member on the bolt being selectively adjustable thereby to open and close the clamp.

11. A clamp according to Claim 10 wherein the clamp members each include a respective, mutually aligned aperture, the bolt passing through the apertures and having a head engageable with the first clamp member and a threaded portion for engaging a portion of a reaction member complementary thereto, the reaction member being arranged to engage the fourth member.

12. A clamp according to Claim 10 or Claim 11 wherein, when the bolt is secured to the reaction member, the bolt is spring biassed to tend to close the clamp.

13. A clamp according to any of Claims 2 to 12 wherein the second and third clamp members each have at least one through-going aperture formed therein, the first and second clamp members being rigidly interconnected by a rod passing through an aperture in the third clamp member, and the third and fourth clamp members being rigidly interconnected by a rod passing through an aperture in the second clamp member.

14. A clamp according to Claim 13 wherein the third clamp member has a plurality of through-going apertures formed therein and the first and second clamp members are rigidly interconnected by a plurality of rods passing through respective apertures in the third clamp member.

15. A clamp according to Claim 13 or Claim 14 wherein the second clamp member has a plurality of through-going apertures formed therein and the third and fourth members are rigidly interconnected by a plurality of rods passing through respective apertures in the third clamp member.

16. A clamp according to any preceding claim wherein the clamp members are constituted by generally circular plates of generally the same diameter as one another.

17. A clamp according to Claim 16 wherein the peripheral portions of opposed surfaces of the clamp members are angled away from one another.

18. A clamp according to any preceding claim comprising a plurality of clamp members in excess of four wherein the (n-2)th clamp member is constrained to move between the (n-l)th clamp member and the nth clamp member between an initial position spaced from the (n-l)th clamp member and a further position closer thereto; and the nth clamp member is constrained to move between an initial position spaced from the ln-2)th clamp member and a further position closer thereto, the arrangement being such that movement of the moveable clamp members occurs simultaneously.

19. A signpost comprising a clamp according to any preceding claim; a post to which said clamp is securable; and a signboard selectively securable in said clamp.

20. A signpost according to Claim 19 including a plurality of signboards selectively securable to said clamp.

21. A signpost comprising a pair of clamps according to any of Claims 1 to 18; a pair of mutually spaced posts to which the respective clamps are securable and at least one signboard securable in and interconnecting said clamps.

22. A signpost according to Claim 21 comprising a plurality of clamps in excess of two, a corresponding plurality of posts to which the respective clamps are securable and a plurality of signboards respectively securable in the clamps so as to interconnect pairs thereof.

23. A signboard adapted for clamping in a clamp according to any of Claims 1 to 18 and/or adapted to form part of a signpost according to any of Claims 19 to 22, the signboard comprising: a first surface adapted to carry or convey information; one or more further surfaces generally perpendicular to said first surface; and a pair of mutually spaced projections extending from the further surface or surfaces beyond the boundary of the first surface, the projections being adapted for securing respectively between opposed clamping members of a clamp according to any of Claims 1 to 18.

24. A signboard according to Claim 23 wherein a or the further surface comprises a folded over portion of the first surface.

25. A signboard according to Claim 24 wherein a or the further surface consists of an edge of a panel constituting the first surface.

26. A signboard according to Claim 23 wherein the first surface is a face of a hollow panel having an open side wall, and the or each further surface is constituted by an insert secured in the open side wall.

27. A signboard according to any of Claims 23 to 26 comprising a plurality of projections in excess of two extending from one or more such further surfaces of the signboard, each projection being adapted for securing between a pair of clamp members of a clamp according to any of Claims 1 to 18.

28. A signboard according to any of Claims 23 to 27 wherein the or each projection comprises a first member adapted for rigid securing to a or the further surface of the signboard; a bifurcated member secured to the first member, the bifurcated member and optionally the first member extending beyond the signboard when the first member is secured as aforesaid; and a pair of spheroidal members respectively secured to the limbs of the bifurcated member, the spheroidal members being suitable for securing between opposed clamp members of a clamp according to any of Claims 1 to 19.

29. A signboard according to Claim 28 wherein the spheroidal members are resiliently deformable.

30. A clamp generally as herein described, with reference to or as illustrated in the accompanying drawings.

31. A signpost generally as herein described, with reference to or as illustrated in the accompanying drawings.

32. A signboard generally as herein described, with reference to or as illustrated in the accompanying drawings.