GB2408449A

GB2408449A - An adjustable support

Info

Publication number: GB2408449A
Application number: GB0327569A
Authority: GB
Inventors: Marshall Young
Original assignee: Coram Showers Ltd
Current assignee: Coram Showers Ltd
Priority date: 2003-11-27
Filing date: 2003-11-27
Publication date: 2005-06-01
Anticipated expiration: 2023-11-27
Also published as: GB0327569D0; GB2408449B

Abstract

An adjustable support comprises a first and a second member (38, 36), each member having respective male and female screw thread formations which inter-engage to couple the members together and provide for adjustment between the members in a direction axially of the screw thread formations, wherein the screw thread 50 of at least one member has at least one raised portion 52 to provide frictional inter-engagement between the portions which resists movement between the members in use.

Description

Title: Adjustable Supports

Description of Invention

This invention relates to adjustable supports, for furniture and the like.

The invention has been devised for use in relation to shower trays, to provide a height-adjustable support therefore, but is applicable to the support of other items or appliances where an adjustable support may be required, for example, baths or kitchen units.

Shower trays, and other articles of fitted furniture such as mentioned above, are commonly raised from an underlying floor surface by a number of supports. This provides access to water supply/disposal pipework or other fixtures arranged beneath the furniture. In order to level the article of furniture the supports are, generally, adjustable for both initial installation and possible re-adjustment, for example, when shrinkage of floor timbers occurs. This is a particular problem with new houses.

It is really quite essential for a shower tray to be adjusted should the floor level change, because otherwise the shower tray may fall or tilt, and the seal at the attachment between the tray and the adjacent wall(s) may crack, causing water leaks.

A typical known adjustable support for a shower tray is shown in Figure 1. In this device, the height of the leg may be altered by unscrewing one of the locking nuts, raising or lowering the bracket in relation to the leg and then tightening the other locking nut. This provides an effective and secure support, but adjustment is difficult, particularly in the confined space underneath the shower tray.

Another type of adjustable leg which can be used is a plastics injection moulded support having two members, connected by a screw thread. Rotating one of the members relative to the other causes an adjustment in height of the support, because of the threaded arrangement. However, this type of leg has not been successful since it is difficult to mould threaded parts in plastic, particularly with larger diameter threads, and so it is difficult to control the dimensions of the thread with sufficient accuracy to ensure a consistent fit between the two members. The members are thus often too loose or too tight and so, if the former, either one must be tightened down to a definite stop position or the pair must be locked using locking nuts. Both of these options complicate the adjustment procedures.

According to a first aspect of this invention there is provided an adjustable support comprising: a first member and a second member, the members having respective male and female screw thread formations which inter-engage to couple the members together and provide for adjustment between the members in a direction axially of the formations, wherein the screw thread formation of at least one member has at least one raised portion to provide frictional inter-engagement between the formations, which resists movement between the members in use.

This invention provides the advantage that the use of no additional locking component(s) is necessary to prevent relative movement of the two members. The parts may be adjusted by hand but the frictional interengagement provided by the raised portion(s) of the inter-engaging screw threads prevents them working loose even under repeated small movements of the two members.

The engaging formations may have a plurality of raised portions, the raised portions being advantageously spaced around the surface of the member.

Advantageously, there are three or four raised portions which may be evenly spaced around the axis of the formations, which maintains the concentricity between the two members.

The or each raised portion may comprise a strip which, advantageously, extends longitudinally to the axis of the support.

The or each raised portion of one member may be arranged to be cut into or deformed by the respective other one of the members to provide the frictional inter-engagement.

One of the members may be a male member and the other member a female member, the members may be connected together with the formations thereof inter-engaging one within the other so that the adjustment changes the overall length of the support.

The or each raised portion may be provided on the male member or the female member or both.

The threads may be of single, or multi-start, type. Advantageously, a trapezoidal or "buttress" thread form is used which enhances the load bearing capacity of the support. Many other type of thread forms might be used.

Preferably at least one of the two members is of a plastics material.

Advantageously the two members are both of plastics materials although possibly one could be of plastics and the other of metal for example. If dissimilar materials are used for the two members then one of the members may be of a relatively hard material and the other member of a relatively soft material. By this it is meant that the material used for one of the members is sufficiently hard to distort, or preferably cut, the other member to enhance the inter-engagement between them.

The two members may be manufactured using a variety of techniques, one convenient technique is injection moulding.

The or each raised portion may be spaced from the end of the member so that as the members first inter-engage there is little frictional contact between them and the amount of friction increases as the two members are moved closer together.

The adjustable support may further comprise a foot, for ground engagement. The foot may have a size similar or comparable to the size of a typical human palm, which enables it to be grasped easily and turned to adjust the support. The foot may be shaped so that it can be easily twisted by hand, S and may be hexagon shaped for turning by a spanner if necessary.

According to a second aspect of this invention there is provided a lengthadjustable support comprising a male member and a female member interengaging by respective co-operating screw thread formations on the members, which self-locks in its adjusted position when adjustment has ceased.

A support according to either the first or the second aspect of the invention may be an elongate leg member, and may be particularly for use in an upright orientation beneath a unit, to support the weight of the unit.

This invention extends to an article of furniture, an article of fitted furniture, and more particularly to a shower tray having the support outlined above, and to an adjustable support for use in any of these articles.

An embodiment of this invention will now be described, to illustrate how these features may be applied by way of example, with reference to the accompanying drawings in which: FIGURE 1 shows schematically an example of a known adjustable support leg; FIGURE 2 shows schematically a cross section of a shower tray, illustrating the support legs; FIGURE 3 shows schematically a perspective view of one of the support legs in more detail; FIGURE 4 shows schematically a cross section through this support leg; FIGURE 5_ shows schematically a side perspective view of the male member of the support leg; FIGURE 5b shows schematically an upper perspective view of this male member; FIGURE 6 shows schematically a section through the portions shown in Figure 5; and FIGURE 7 shows schematically a different section showing where there is frictional interengagement.

The way in which shower trays have traditionally been supported is shown schematically in Figure 1. This illustrates a support 10 comprising a top bracket 12, a screw-threaded leg 14 and a ground-engaging foot 16. The bracket has supporting limbs 18 which extend generally horizontally to support a shower tray 20, being connected thereto by screws 22. These limbs taper downwardly to a generally horizontal plate 24 containing a threaded hole 26 through which the leg extends in use. The leg is secured in position in relation to this bracket by two locking nuts 28, which engage with the thread on the leg.

In order to provide access to the upper locking nut the bracket is shaped to create a space 30 between its leg-engaging plate 24 and its upper support limbs 18.

The bracket, and hence the shower tray, may be moved upwards by unscrewing the upper locking nut, moving the bracket upward by turning the leg and then screwing up the lower locking nut. Thus adjustment is a difficult, and fiddly operation particularly as the bracket occupies such a large amount of space.

Figure 2 shows a shower tray 32 and three support legs 34 therefor. If the tray is rectangular in plan view, it may have one leg adjacent to each corner and one in or around the centre. It can be seen that each leg 34 comprises two members, namely an upper member 36 and a lower member 38 that terminates in a ground engaging foot 40. The members have respective male and female formations which inter-engage to provide for adjustment of the height of the leg. The upper member has an annular support flange 42 at its upper end upon which the shower tray may rest and which may be fixed to the shower tray be mechanical fasteners such as screws 44.

A leg 34 is shown in more detail in perspective in Figure 3, and Figure 4 shows schematically a section through the leg 34.

From these drawings it may be seen that the member 36 provides a female socket formation in which the male lower member 38 may be inserted.

A female screw thread 46 is provided on an inner surface 48 of the female member 36, at the lower end only thereof and the thread 46 is engageable with a complementary thread 50 provided on the male member 38.

This thread 50 is interrupted by a number of longitudinally extending raised strips 52, as may be most clearly in Figure 5b. The strips 52 are spaced around the circumference of the male member. Four strips are provided, being equally spaced around the thread axis in the same axial plane and this enables the male and female members to be kept concentric to each other. These strips 52 protrude from an outer surface 54 of the body of the male member beyond the root diameter of the screw thread thereon, for a distance which is substantially equal along their longitudinal length. As is also shown in this figure the strips are raised by an amount which is less than the crests 56 of the thread 50.

The raised strips run parallel to the axis of the thread and to the axis of adjustment of the two members.

For most of the thread, therefore, there is clearance between the male and the female members, as is shown in Figure 6. Over the area covered by the raised strips, however, there is positive engagement between the male and female members. In essence, the female thread on the female member cuts into the raised strip on the male member, in effect cutting its own thread. This removes any clearance between the two members which may arise due to variations in size as a result of manufacture and create substantial frictional inter-engagement between the two members.

The raised strips are relatively narrow forming only a small proportion of the total thread area. Therefore, the frictional inter-engagement created is low enough to enable the shower tray foot to be turned by hand, yet high enough to prevent the foot unscrewing due to natural movement of the tray.

The width or the height of the raised strips may be adjusted to provide the amount of frictional inter-engagement desired.

By way of example, the total area of the raised strips may be about 2% of the total area of the engaged threads. In an embodiment comprising two buttress-threaded members moulded of polystyrene, each of the four strips may be 2mm wide and interfere with the female thread to a depth of 0.25mm. To limit the total friction, the interference is effective over about 10 turns only of the thread as referred to hereafter. The friction created is of course dependent on the materials used and the form of the threads, as well as the dimensions and number of the strips, and by way of example the friction may cause the torque needed to adjust the support to be of the order of 0.5Nm: this provides an adequate locking effect while still being adjustable by hand.

The load-bearing capabilities of the support are enhanced by the frictional inter-engagement provided, in particular the increased surface area provided as the female thread cuts into the male thread reduces the stress on the components and enables a greater axial load to be supported.

As can be seen most clearly in Figures 5 the raised strips do not extend along the entire length of the thread, but only along about the lower 80% thereof. By stopping the raised strips short of the top of the thread the male thread is easily aligned and engaged in the female thread for the first few turns, which makes assembly easier. The thread is noticeably looser during these first few turns, so that as the strips are engaged a tactile warning is provided, and the user can tell when frictional interengagement will take place. This is particularly important with weak plastic threads, because if the shower tray were raised too high then there might be insufficient thread engagement to bear the load required in use. The exact proportion of the longitudinal extent of the strip may vary, it is advantageous if the strips extends over the majority of the length of the thread, and more advantageous still if the thread extends more than 75% but less than 85% of the length of thread.

Since the female thread 46 is provided in the lower end part only of the member 36, and is of lesser extent axially of the member 36 than the extent of the thread 56 on member 38, the two threads engage over a length which is constant over a wide range of adjustment of the members. This means that the force required to adjust the support leg remains constant over that range of adjustment. The same effect could be achieved if the member 36 were threaded in its entire interior, but the strips 52 extended over about 10 turns only of the screw thread 56. If the entire interior of the member 36 were threaded, the increased length of thread in engagement would cause the adjustment to become stiffer, i.e. more difficult to effect, as the support leg is shortened.

The foot 40 is hexagon-shaped and in diameter somewhat less than the span of a human palm i.e. that of a human hand when considered without the fingers attached. The hexagon shape permits the use of a spanner to adjust the foot, but it may be turned easily by hand if required.

To connect the shower tray leg to the shower tray the female member is attached to the lower surface of the tray 18 by placing the support flange 42 against the lower surface and screwing them together. The shower tray may then be manoeuvred into its final position, and the male member of each support screwed into the female member. The absence of a raised strip on the first few turns of the thread enables this to be accomplished fairly easily. The male member 36 is then screwed further into the female member until frictional inter-engagement has taken place. Once all of the shower legs are so engaged they may be relatively easily adjusted to level the shower tray, and the feet are then fastened to the floor by mechanical fasteners such as screws 56. To readjust the tray the screws are removed and the foot may be adjusted by hand as described earlier.

The advantages of this support system compared to that shown in Figure 1 may easily be seen.

For example, the entire space between the ground and the lower surface of the shower tray may be used to achieve the adjustment. The adjustment may be performed with one hand and it is only necessary to turn one component.

The skilled reader will appreciate that this invention provides a selflocking adjustable support which greatly facilitates the adjustment between two members, and is especially suitable for adjusting furniture, in particular fitted furniture.

It will be appreciated by those skilled in the art that modifications may be made from the above-described construction whilst remaining within the scope of the invention. For example, the raised strips may extend helically instead of axially. Strips of a different (softer) material than the screw threads may be utilised: such strips may be attached mechanically, by friction, or by over-moulding the base material.

In the present specification "comprises" means "includes or consists of" and "comprising" means "including or consisting of".

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. An adjustable support comprising: a first member and a second member, the members having respective male and female screw thread formations which inter-engage to couple the members together and provide for adjustment between the members in a direction axially of the screw thread formations, wherein the screw thread formation of at least one member has at least one raised portion to provide frictional inter-engagement between the formations, which resists movement between the members in use.

2. An adjustable support according to claim 1 in which the screw thread formations have a plurality of raised portions.

3. An adjustable support according to claim 2 in which the raised portions are spaced around the surface of the member.

4. An adjustable support according to claims 2 or claim 3 comprising three or more raised portions.

5. An adjustable support according to claim 3 or claim 4 in which the raised portions are evenly spaced circumferentially of the formations.

6. An adjustable support according to any preceding claim in which the or each raised portion comprises a strip of material.

7. An adjustable support according to claim 6 in which the or each strip extends longitudinally in relation to the axis of the formations.

8. An adjustable support according to claim 6 or claim 7, wherein the strip interrupts the screw thread on the member wherein it is provided, and is raised beyond the root diameter of the thread.

9. An adjustable support according to any preceding claim in which the or each raised portion is arranged to be cut into or deformed by the respective other member, to provide the frictional inter-engagement.

10. An adjustable support according to any preceding claim in which one of the members is a male member and the other member a female member, the members being connected together with the formations thereof interengaging one within the other so that the adjustment changes the overall length of the support.

11. An adjustable support according to claim 10 in which the or each raised portion is provided on the male member.

12. An adjustable support according to any one of the preceding claims in which the thread has a trapezoidal form.

13. An adjustable support according to any preceding claim in which the two members are of plastics material.

14. An adjustable support according to claim 13 in which the two members are manufactured by injection moulding.

15. An adjustable support according to any preceding claim in which the two members are of material of different hardness from one another.

16. An adjustable support according to any preceding claim in which the or each raised portion is spaced from the end of the member.

S

17. An adjustable support according to claim 7 or any claim appendant thereto wherein the screw thread on one member not having the raised portion(s) extends axially of that member by a distance less than the axial extent of the raised portion(s) on the other member.

18. An adjustable support according to any preceding claim further comprising a foot on one member, for ground engagement.

19. An adjustable support according to claim 18 wherein the foot is turnable to adjust the support.

20. An adjustable support according to claim 18 or claim 19 in which the foot has a size similar or comparable to the size of a human palm.

21. An adjustable support according to claim 19 or claim 20 wherein the foot is shaped for engagement by a spanner.

22. A length-adjustable support comprising a male member and a female member inter-engaging by respective co-operating screw thread formations on the members, which self-locks in its adjusted position when adjustment has ceased.

23. An adjustable support according to any preceding claim in which the support forms an elongate leg.

24. An adjustable support according to any preceding claim for use in an upright orientation beneath a unit, to support the weight of the unit.

25. An article of furniture comprising an adjustable support according to any preceding claim.

26. An article of fitted furniture comprising an adjustable support according to any of claims 1 to 24.

27. A shower tray comprising an adjustable support according to any of claims 1 to 24.

28. An adjustable support according to any of claims 1 to 24 for use with an article of furniture.

29. An adjustable support according to any of claims 1 to 24 for use with an article of fitted furniture.

30. An adjustable support according to any of claims 1 to 24 for use with a shower tray.

31. An adjustable support substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

32. Any novel feature or novel combination of features described herein and/or in the accompanying drawings.