Background of the Invention Over recent times more emphasis has been placed on making furniture more versatile and ergonomic. Increased versatility means that furniture such as chairs, tables, desks and workbenches can be designed with a number of different applications in mind. For example, desks can be designed for use as a traditional desk or alternatively, as a workbench which may be designed for use in a standing, rather than seated, position.

People responsible for educational and work environments are becoming increasingly aware of the importance of providing environments which satisfy ergonomic requirements of people in those environments. This may involve tailor- making furniture to an individual's requirements. However, more commonly, it involves providing furniture which can be adjusted to suit different people's needs.

While there are a large number of adjustable furniture items available the adjustable mechanisms of these items are typically specifically designed for use in relation to a particular furniture item. For example, some forms of adjustable chairs include a pneumatic adjustment mechanism and some forms of adjustable desks have support members which include a number of holes corresponding to different height positions of a horizontal work surface.

Summary of the Invention It is therefore desirable to provide an alternative adjustment mechanism suitable for use with components commonly used to form furniture such as metal rods or tubes to provide a more versatile and/or improved means of assembly of adjustable furniture.

In a first aspect, the present invention provides an attachment device for attachment of a first elongate member to a second member, the attachment device comprising an attachment member having an annular portion and fingers

which extend from the annular portion, said fingers extending in a direction which is substantially aligned with a longitudinal axis of said annular portion, inner surfaces of said fingers being arranged, upon application of a clamping force thereto, to clamp against an external surface of the first elongate member.

Suitably, the attachment member comprises three or more fingers.

Preferably, the annular portion is substantially cylindrical in shape.

An external surface of the fingers preferably tapers radially inwardly towards said longitudinal axis, from the annular portion towards a region proximate free ends of said fingers.

The attachment member is preferably arranged to clamp to a tube or rod via a clamping means having a clamping surface arranged for contact with an external surface of said fingers and arranged for relative movement away from said free ends, in a direction substantially aligned with said longitudinal axis.

The clamping surface is preferably annular in shape and has a taper that is complementary to the tapered external surface of the fingers.

Suitably, the clamping means comprises two clamp components arranged to be drawn toward each other, preferably via bolts or screws.

In one preferred form, the attachment member is arranged to attach two substantially aligned tubes or rods together. In this preferred form, the tube or rod attachment member comprises two sets of fingers which extend away from each other and said annular portion. Preferably, said tapered external surfaces corresponding to the separate sets of fingers meets substantially mid-way along a length of the annular portion which joins the separate sets of fingers. Preferably, the clamping means comprises two substantially identical clamp components.

Fingers of the attachment member of the first aspect of the present invention are not limited to any particular shape. However, in one preferred embodiment they are generally rectangular in shape. In another preferred embodiment the fingers are also curved in a direction transverse to said longitudinal axis. The inner surface of the attachment member is preferably substantially cylindrical so as to fit over a substantially cylindrical rod or tube.

In a second aspect of the invention there is provided an attachment assembly for attaching a first elongate member to a second elongate member comprising: a first attachment member having an annular portion adapted to extend

around the first elongate member and fingers which extend from said annular portion, said fingers extending in a direction which is substantially aligned with a longitudinal axis of said annular portion; a clamping means comprising at least two clamp components, the clamping means having at least one clamping surface adapted to extend around a second elongate member wherein said at least one clamping surface is arranged to bear upon an external surface of the second elongate member to clamp the second elongate member between the clamp components when the clamp components are drawn towards each other; wherein at least one of the clamp components is arranged to apply a clamping force to the fingers when the clamp components are drawn towards each other so that inner surfaces of the fingers clamp against an external surface of the first elongate member.

In a third aspect of the invention there is provided an adjustable attachment device for clamping at least one elongate member, said attachment device comprising a clamping means having at least two clamp members with non- clamping surfaces adapted to extend around the elongate member when the clamp members are clamped together, the clamping means including at least one clamping surface which is arranged to depress an external surface of the elongate member when the clamp members are clamped together.

Preferably, the clamp members are arranged to abut one another when clamped together around the elongate member. In this position, the clamping surface or surfaces engage with and depress the external surface of the elongate member to clamp the elongate member relative to the clamp members.

In a preferred embodiment for use with a substantially cylindrical elongate member such as a rod or tube, the clamping members have substantially arcuate clamping surfaces with a radius of curvature slightly less than the radius of curvature of the external cylindrical surface of the rod or tube. The non-clamping surfaces may also be arcuate surfaces, but with a radius of curvature equal to or greater than the radius of curvature of the external cylindrical surface of the rod or tube.

In a preferred embodiment, the clamp members may have outer arcuate non-clamping surfaces formed in mating clamp members, and inner arcuate clamping surfaces formed in the mating clamp members.

Said outer arcuate non-clamping surfaces may be formed in outer walls of

the clamp members. Suitably, said one or more inner arcuate clamping surfaces are provided by edges of one or more intermediate walls positioned between said outer walls.

In a particularly preferred embodiment, each clamp member has two outer and three inner arcuate surfaces.

Suitably, said at least two clamp members are arranged to clamp together via screws or bolts.

The clamp components of the first and second aspects of the present invention and/or the clamp members of the third aspect of the present invention may be formed by castings. One clamp component or member is preferably arranged for attachment to a corresponding component or member to form the clamping means of the first or second aspect and/or of the third aspect of the present invention.

Two or more different clamping components or members may be provided by a common housing or casting for clamping a plurality of elongate members.

In a particularly preferred embodiment, said clamp components of the first aspect of the invention may be orientated relative to said clamp members of the third aspect of the invention for clamping tubes, pipes and/or rods which may be orientated substantially perpendicularly to each other.

In a fourth aspect, the present invention comprises a tube, pipe and/or rod assembly comprising two or more tubes, pipes and/or rods attached together by the tube or rod attachment member of the first aspect of the present invention and/or the tube or rod attachment member of the third aspect of the present invention.

Brief Description of the Drawings A preferred embodiment of the invention will now be further described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is an exploded assembly drawing of one example of a table support in accordance with the present invention; and Figure 2 is an enlarged perspective view of one of the casting members of the assembly.

Preferred Embodiments Referring to Figure 1, one example of an adjustable mechanism of the present invention generally comprises mating castings 10a and 10b and tube or

rod attachment members in the form of ferrules 12a and 12b. The ferrules 12a and 12b are designed to be received and clamped between the mating castings 10a and 10b. The castings 10a and 10b are one example of clamp components or clamp members of the present invention. The castings 10a and 10b also provide one example of: clamping means of the first aspect of the present invention having tapered annular clamping surfaces 14a and 14b which surround circular apertures 15a and 15b; and a clamping means of the second aspect of the present invention in the form of semi-circular clamps 16a and 16b.

The ferrules 12a and 12b are identical and each has a central annular band 18. The ferrules 12a and 12b also include two sets of fingers 20a and 20b, and 22a and 22b, which extend away from the central annular band 18. An external curved surface 23 of the ferrules 12a and 12b tapers radially inwards along its longitudinal length from a point mid-way along the length of the central annular band 18 toward free ends of the fingers 20a, 20b, 22a and 22b, so that the diameter of the central annular band 18 is greater than the diameter of a circle containing the end regions of the fingers 20a, 20b, 22a and 22b. The fingers extend in a direction which is substantially aligned with a longitudinal axis of the central annular band 18.

As can be seen in Figure 1, the castings 10a and 10b are designed to be clamped together via bolts 24,26, 28 and 30 extending through apertures 25,27, 29,31 in the castings 10a and 10b in a manner which results in the semi-circular clamps 16a and 16b being drawn together around a cylindrical member such as a horizontal rod or pipe 32. As the castings 10a and 10b are drawn together, the tapered clamping surfaces 14a and 14b are forced toward each other over the external curved surface 23 of ferrules 12a and 12b, from opposite ends of ferrules 12a and 12b. The tapered clamping surfaces 14a and 14b apply an inwardly directed clamping force to the fingers 20a and 20b, and 22a and 22b, as the cylindrical clamp surfaces 14a and 14b move over the external tapered and curved surface 23 of the ferrules 12a and 12b.

The size of the ferrules 12a and 12b is such that ends of the ferrules 12a and 12b defined by free ends of the fingers 20a, 20b, 22a and 22b fit freely over ends of respective cylindrical members, such as vertical rods or pipes 36 and 52.

With the ferrule 12a in the undamped position shown in Figure 1, its lower end only may be fitted over the rod or pipe 36, or it can be moved further along the length of the rod or pipe 36 so that an upper end 38 of the rod or pipe 36 extends

through the ferrule 12a. With the ferrule 12a positioned in either of these positions, or some intermediate position therebetween, drawing of castings 10a and 10b toward each other via bolts 24,26, 28 and 30 results in the fingers 20a and 22a being forced radially inwards towards each other to clamp against an external surface 40 of the rod or pipe 36. The size of the tapered clamping surfaces 14a and 14b and the geometry of the taper of the external curved surface 23 is such that when the castings 10a and 10b are fully tightened or clamped relative to each other so that mating edges 42a and 42b abut, the clamped casting 10a and 10b is firmly fixed relative to the rod or pipe 36.

The semi-circular clamps 16a and 16b each include two outer arcuate surfaces 44a, 44b and three inner arcuate surfaces 48a, 48b, 48c. The outer arcuate surfaces 44a and 44b are one example of non-clamping surfaces of the present invention and are provided by side walls 46a and 46b, respectively, of castings 10a and 10b. The inner arcuate surfaces 48a, 48b and 48c are one example of clamping surfaces of the present invention and are provided by three internal walls 50a, 50b and 50c, respectively, positioned between the side walls 46a and 46b. The wall 50b is positioned mid-way between the side walls 46a and 46b. The walls 50a and 50c are each equidistantly spaced either side of the central wall 50b.

The non-clamping surfaces 44a and 44b have a radius of curvature which is slightly greater than or equal to a radius of curvature of the pipe 32 so that when the castings 10a and 10b are fully clamped to each other with the edges 42a and 42b abutting each other, the non-clamping surfaces 44a and 44b form a cylindrical surface around the rod or pipe 32. The clamping surfaces 48a, 48b and 48c have a radius of curvature which is slightly less than the radius of curvature than the non-clamping surfaces 44a and 44b. The clamping surfaces 48a, 48b and 48c are accordingly positioned slightly proud of the non-clamping surfaces 44a and 44b so that as the castings 10a and 10b are drawn toward each other via bolts 24,26, 28 and 30, the clamping surfaces 48a, 48b and 48c are forced against an external surface of the rod or pipe 32 until the edges 42a and 42b abut. Depending on physical properties of the rod or pipe 32, the clamping surfaces 48a, 48b and 48c either elastically or non-elastically deform an external surface of the rod or pipe 32. In either case, however, upon abutting contact of the edges 42a and 42b, the castings 10a and 10b are securely fixed relative to the rod or pipe 32. The pipe 32 may be provided with an end cap 33.

As can be seen in Figure 1, the castings 10a and 10b and corresponding ferrules 12a and 12b can be used to adjustably attach lower rods or pipes 36 and 52 to the upper horizontal pipe 32 to form a support for a table (not shown). A castor wheel 54 is pivotally attached to a lower end of the rod or pipe 36 forming a rear table leg and a corresponding castor wheel (not shown) may be pivotally attached to a lower end of rod or pipe 52 forming a front table leg. The rod or pipe 52 has a substantially vertically extending upper portion 51 joined to an inclined lower portion 53 by an elbow joint 58. The castings 10a and 10b can be moved upwardly and downwardly relative to the rods or pipes 36 and 52 to adjust the height of the horizontal rod or pipe 32 and upper surface 56 of the casting 10a.

However, due to an upper elbow 58 in the rod or pipe 52 the casting 10a and 10b cannot be moved downwardly beyond the elbow 58. The castings 10a and 10b can be moved along the length of the rod or pipe 32 to adjust the lateral position of the castings 10a and 10b relative to the pipe 32.

Referring to Figure 1, a table support bracket 60 can be attached to the upper surface 56 of the casting 10a via screws 62a and 62b adapted to extend through holes 63a, 63b in the bracket 60. The table support bracket 60 is designed to support one end of a table (not shown) via screws (not shown) which thread into holes 64a, 64b and 64c of the table support bracket 60. An opposite end of the table to that which is supported by the table support bracket 60 is supported by a corresponding table support bracket (not shown) which itself is supported by a casting assembly and legs (not shown) corresponding to casting 10a and 10b and pipes 36 and 52.

Just as the ferrules 12a and 12b attach to pipes 36 and 52, they can also attach to pipes (not shown) which extend upwardly of the castings 10a and 10b. In such an embodiment the ferrules 12a and 12b are clamped to an upper end of pipes 36 and 52 preferably so that the pipes do not extend upwardly beyond a longitudinal mid-point of the ferrules 12a and 12b. Upper ends of the ferrules 12a and 12b can then be fitted over lower ends of upper pipes (not shown) for clamping of the ferrules 12a and 12b to the upper pipes in a similar manner to that described above in relation to the pipe 36. When the castings 10a and 10b are appropriately tightened relative to each other via bolts 24,26, 28 and 30 the pipes 36 and 52 are joined to the upper pipes (not shown). Such an embodiment provides an arrangement which is suitable, for example, for supporting a shelf which is positioned above the table (not shown).

While the castings 10a and 10b and corresponding ferrules 12a and 12b are shown in Figure 1 in relation to adjustable assembly of a table, these castings and ferrules, or alternative castings which include specific combinations of tapered clamping surfaces corresponding to annular tapered clamping surfaces 14a and 14b and/or semi-circular clamps corresponding to semi-circular clamps 16a and 16b (and corresponding ferrules), can be used to form other adjustable items of furniture including chairs, tables and work benches. For example, a height adjustable chair can be formed using a casting (not shown) that includes three or more pairs of annular tapered clamping surfaces similar to pairs of cylindrical clamp surfaces 14a and 14b, but not semi-circular clamps corresponding to semi- circular clamps 16a and 16b.

As will be readily apparent to a person skilled in the relevant art, the castings 10a and 10b and ferrules 12a and 12b can be formed from any suitable materials. For example, the castings 10a and 10b are formed of any suitable casting metal. However, they can also be formed of strong and rigid plastic.

The ferrules 12a and 12b can also be formed of metal or reasonably rigid and strong plastic. However, they are typically formed of plastic. For repeated use of the ferrules 12a and 12b the combination of their dimensions and materials should be such that the fingers 20a and 20b, and 22a and 22b, return to the unclamped position as shown in Figure 1 upon loosening of the bolts 24,26, 28 and 30 and subsequent unclamping of the ferrules 12a and 12b. Furthermore, in order for the ferrules 12a and 12b to firmly locate castings such as castings 10a and 10b relative to pipes such as pipes 32 and 52, the fingers 20a and 20b, and 22a and 22b require a certain amount of rigidity so that appropriate clamping force is applied to an external surface of pipes upon tightening of bolts 24,26, 28 and 30 and subsequent abutting contact between abutting edges 42a and 42b.

It will be understood that the invention disclosed and defined in this specification extends to all alternative combinations of two or more of the individual features mentioned or evident from the text and or drawings. All of these different combinations constitute various alternative aspects of the invention.

Various changes and modifications may be made to the embodiments described and illustrated without departing from the present invention.

It will be appreciated that various modifications and alterations may be made to the embodiments of the present invention described above without departing from the scope or spirit of the present invention.