Technical Field The present invention relates to a height adjustable table.

Background Art Height adjustable tables have been produced which incorporate mechanisms for adjusting the height of the table. Such tables however have a tendency to be unstable (eg. wobbly).

Summary In a first aspect the present invention provides a height adjustable table including at least one mechanism for adjusting the height of the table, the mechanism including: first and second members being pivotally connected together about a pivot axis and the relative movement of the first and second members is substantially confined to rotation about the pivot axis only; the first member includes a first engagement region being spaced away from the pivot axis; the second member includes a second engagement region being spaced away from the pivot axis; and means for effecting pivotal movement of the first and second members about the pivot axis, whereby the height of the table is adjusted. The first and second members may pivot about a hinge. The first and second members may include pairs of arms extending away from the pivot axis and the engagement regions are generally at the ends of the arms. The means for effecting pivotal movement may include a screw threaded adjuster. The first engagement region may engage a leg assembly of the table. The table leg assembly may be rotatable to provide for a collapsed table configuration. The second engagement region may engage a tabletop of the table. The table may include two mechanisms for adjusting the height of the table. The two mechanisms may be associated with one another so that the means for effecting pivotal movement in each mechanism operate in unison. The two mechanisms may be arranged so that they pivot in different directions of rotation.

FP21816 The two mechanisms may be located generally at either end of the table.

Brief Description of the Drawings An embodiment of a height adjustable table incorporating a distance adjustment mechanism will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is an underside perspective view of a table fitted with a pair of distance adjustment mechanisms; Figure 2 is side view of the table of figure 1; Figure 3 is an underside view of the table of figure 1 ; Figure 4 is an end view of the table of figure 1; and Figure 5 is a side view of the table of figure 1 in a collapsed configuration.

Detailed Description of a Specific Embodiment Referring predominantly to Figure 1, and also with reference to figures 2 and 3, a height adjustable table 10 is shown including a tabletop 12 and a table frame assembly 14. Table frame assembly 14 includes a pair of identical distance adjustment mechanisms 20. Each mechanism 20 includes a first rigid member 22 formed by parallel arms 23 connected to either end of tube 24. Arms 23 are connected to tube 24 in such a way as to prevent independent movement of either of arms 23 to maintain arms 23 parallel to one another. Each mechanism 20 further includes a second rigid member 25 formed by parallel arms 26 rigidly connected to a spindle (not shown). Arms 26 are keyed to the ends of the spindle and retained with hex bolts to prevent independent movement of either of arms 26 to maintain arms 26 parallel to one another. Each spindle sits inside tube 24 to provide a pivotal connection of the first 22 and second 25 members about pivot axis indicated by broken line 27. The tube 24 and spindle arrangement confines relative movement of first member 22 and second member 25 to pivotal movement about pivot axis 27 only. First member 22 has a first engagement region formed by pivot points 28 at the ends of arms 23 and which engage table legs assembly 30. The pivot points 28 are spaced apart across the entire width of first member 22 being the distance between the ends of arms 23. Second member 25 has a second engagement region formed by pivot points 29 at the ends of arms 26 and which engage table top 12 by way of brackets 32. The pivot points 29 are spaced apart across the entire width of second member 25 being the distance between the ends of arms 26. Means for effecting movement is provided in the form of adjustable columns 33, each of which is made up of an outer tube 34 welded to leg assembly 30, and an inner rod 36. Drive shaft 40 extends between the two adjustable columns. At each column, drive shaft 40 engages with a bevel gear (not shown) mounted inside column 33. Drive shaft 40 is connected to handle 42 by way of a gear train (not shown). Rotation of handle 42 causes rotation of drive shaft 40 which in turn causes rotation of both bevel gears in unison. Rotation of a bevel gear causes movement of the inner rod 36 with respect to outer tube 34 so that inner rod 36 either extends further out of, or retracts into, tube 34. The direction of movement of inner rod 36 depends on the direction of rotation of handle 42. Movement of inner rod causes relative pivotal movement between first member 22 and second member 25. The distance between pivot point 28 and pivot point 29 varies with pivotal movement of the first 22 and second 25 member. The distance adjustment mechanisms 20 serve to stabilise tabletop 12 regardless of the position of adjustable columns 32. By way of explanation, and with reference to figure 4, a force F1 applied at the edge of tabletop 12 gives rise to downwards force F2 at pivot point 29. Force F2 is transmitted to act downwardly on the opposite side of tabletop F3 by way of the pivotal freedom of second rigid member 25. Force F3 sets up a moment M about the width of tabletop 12 which serves to counteract force Fi. Comparing figures 2 and 5, table 10 is shown in erected and collapsed configurations respectively. To move from the erected configuration shown in figure 2 to the collapsed configuration of figure 5, crossbar 44 is firstly pulled from sockets 45 provided in both leg assemblies 30. Each leg assembly can then be rotated about pivot points 28 to bring the legs of the table towards one another. This rotation allows removal of drive shaft 40 from engagement with bevel gears in both of adjustable columns 32. Leg assemblies 32 are further rotated to bring them to the position shown in figure 5. Crossbar 44 and drive shaft 40 can be stowed under tabletop 12. The collapsed configuration of figure 5 provides a compact arrangement useful for shipping or storage of table 10. In the above described embodiment the means for effecting pivotal movement of the first and second members operates substantially in the direction of the distance being adjusted. Alternatively, the means for effecting movement can operate in a different direction. It can operate transverse to the distance being adjusted such as by pulling together tubes 24 in the above described embodiment. Similarly, the means for effecting movement can operate at an angle to the distance being adjusted. In the above described embodiment the means for effecting movement operated by way of a screw threaded arrangement. Similarly, other means can be used such as hydraulic means eg. a hydraulic ram. - A -

In the above described embodiment the table included two distance adjustment mechanisms. Similarly, more than two such mechanisms can be used. In this specification the word "table" means a table, bench, workstation or other horizontal work surface. Any reference to prior art contained herein is not to be taken as an admission that the information is common general knowledge, unless otherwise indicated. Finally, it is to be appreciated that various alterations or additions may be made to the parts previously described without departing from the spirit or ambit thereof.