GB2238505A

GB2238505A - Work supports

Info

Publication number: GB2238505A
Application number: GB8926172A
Authority: GB
Inventors: Robert Davenport
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-11-20
Filing date: 1989-11-20
Publication date: 1991-06-05
Also published as: WO1991007257A1; GB8926172D0

Abstract

The present invention provides a work support arranged to support and optionally to grip, a workpiece, such as a plank of wood, above the ground. The work support may particularly be in the form of a foldable trestle (10), comprising a single work support member (12), foldable legs (14, 15) arranged to support the support members above the ground; and clamping means (34) arranged to engage or grip a workpiece (12) when it is resting upon the support member.

Description

IMPROVEMENTS IN OR RELATING TO WORK SUPPORTS This invention relates to a work support which tinds particular but not exclusive application in the support of an elongate workpiece for a user two perform some operation on that workpiece. The workpiece may comprise, for example, a plank, beam, rod, tube or sheet, and may be formed of materials such as timber, metal or plastics. The work support may support the workpiece either alone at one end of the workpiece, or in cooperation with a further item of the invention (or some other means of support) located at the opposite end of the workpiece.

In one particular application, two work supports of the invention may be used to support a plank above the ground to form a platform upon which workers may stand to gain access to or to work on something which is normally out of reach.

It is an object of the present invention to provide an improvement upon, or a replacement for, the type of work support conventionally referred to as a trestle, such as are used by carpenters to support a plank or timber or used to support a table or other flat surface for various purposes.

Accordingly in one aspect the present invention provides a work suppdrt comprising a single work support member; means to support the work support member above the ground; and clamp means associated with the support member, arranged to engage or grip a workpiece when it is resting on the support member.

In a further aspect, the present invention provides a work support trestle comprising a clamp means arranged to engage or grip a work piece when it is resting on the work support member of the trestle.

In a yet further aspect, the present invention provides a work support member with associated clamp means arranged to engage or grip a workpiece when it is resting on the support member.

Preferably the support member in any of the above aspects is of inverted "U" shaped or channel cross section.

Preferably the upper surface of the support member is rounded.

Preferably the clamp means in any of the above aspects, comprises a pair of spaced clamp members at least one of which is movable along the support member between an open position and an operative or clamp position engaging or gripping a work piece when it is resting on the support member. Where both clamps are movable, the clamps preferably move equally in opposite directions between the two positions such that the workpiece is always clamped centrally on the support.

Preferably the clamp means includes manually operable means to move such clamp member or members between the said positions.

Preferably the clamp means includes a lead screw having portions of opposite handed thread, and each of the clamp members is in screw threaded engagement with a respective handed portion of the lead screw.

Preferably the clamp means includes a handle at the side of the work support or trestle by which such lead screw may be rotated to move the clamp members.

Preferably at least one such clamp member is slideably mounted on the support member for movement along the support member, while being located on the support member against rotation about the support member.

Preferably the clamp members are formed with flat surfaces to provide a support face for a flat work piece which is too wide to fit between the clamp members in their fully opened position.

Preferably the clamp members are formed with an aperture corresponding in shape to the cross section of the support member, the clamp member sliding along the support member by means of such aperture.

Preferably such lead-screw is disposed within the cross section of the support member.

Preferably the lead screw is carried in journal bearings disposed one at each end of the support member, and in a thrust bearing arrangement provided at one or both ends of the lead- screw to axially located the lead screw relative to the support member.

Preferably in any of the above aspects of the invention means provided to support the support member above the ground comprises a foldable support structure.

Preferably such support structure is adjustable in height.

Preferably such support structure comprises two leg assemblies at least one of which is pivotedly mounted on or adjacent the support member.

Preferably each such leg assembly comprises a pair of legs extending from the support member to the ground and connected by a base member arranged to lie on or immediately adjacent the ground.

Preferably the support member is rigidly attached to a first of such leg assemblies, while the second leg assembly is pivotedly mounted on the first leg assembly adjacent the support member.

Preferably the second leg assembly is arranged to fold to lie within the plane of the first leg assembly in a closed or storage position.

Preferably each such base member is provided with a pair of spaced ground engaging feet.

Preferably latch means is provided to locate the leg assemblies relative to one another in an open or operative position at a chosen angle to one another.

Preferably such latch means is arranged to so locate the leg assemblies at a plurality of chosen angles to one another.

In order to promote a fuller understanding of the above, and other, aspects of the present invention, an embodiment will now be described, by way of example only, with reference to the accompanying drawings in which Figure 1 is a general schematic view of a work support embodying the invention, Figure 2 is an exploded view generally similar to that of Figure 1 showing the same embodiment, Figure 3 shows the embodiment of Figure 1 folded and hanging from two pegs on a wall, and Figure 4 shows a schematic part cross sectional view showing the mounting of the clamp members of Figure 1 on the support member.

Figure 1 shows in a perspective view, an embodiment of the invention in the form of a work trestle (10) supporting one end of a wooden plank (11).

The trestle comprises a support member (12) arranged to be supported above the ground at a chosen height, by a foldable support structure (13) which comprises two leg assemblies (14, 15). The leg assemblies (14,15) each comprise a pair of legs (16) which are connected at the bottom by a base member (17) arranged to lie on or immediately adjacent the ground. The leg assemblies are formed from tubular metal and the base members (17) are each provided with a pair of spaced ground engaging feet (18) which, in this embodiment, take the form of circular synthetic plastics material clips positioned around the base member.

The leg assembly (14) is rigidly attached to the support member (12), while the leg assembly (15) is pivotally mounted at the points (19) adjacent to the support member (12), on the leg assembly (14). Each leg (16) of the leg assembly (15) is provided with a pivotal latch member (20) which has a hooked end to engage in an aperture (21) in the corresponding leg (16) and the leg assembly (14), to hold the leg assemblies in an open or operative position as shown in Fig.1. A number of apertures (21) may be provided along the length of the leg (16) of the leg assembly (14) to enable the trestle to be set at a number of different heights.

The support member (12) comprises a beam (30) which is of a generally inverted "U" shaped or channel cross section, and it is mounted on the leg assembly (14) by means of mounting members (31). The mounting members (31) have plugs (32) arranged to locate inside the cross section of the beam (30) and to be attached thereto by means of pins or bolts, or other suitable means not shown. The mounting members (31) also have mounting bosses (33) which fit over the respective leg (16) of the leg assembly (14) and which are attached thereto again by pins or bolts or other suitable means not shown. The bosses (33) might alternatively fit within the tubular legs (16).

A pair of clamp members (34) are mounted on the beam (30) by means of apertures (35) which correspond in shape to the cross section of beam (30), so that the clamp members are free to slide along the beam (30) while being located against rotation about the beam. A lead-screw (36) is mounted for rotation in and axially located in the mounting brackets (31), in such position to lie within the cross section of the beam (30). A handle (40) is provided on one end (41) of the lead screw outside one mounting bracket (31), and arranged so that it may be used to rotate the lead-screw manually in either direction. The lead screw (36) is provided with two portions (37,38) each of opposite handed thread which engage in respective correspondingly handed threaded apertures (39) formed in the clamp members (34).Thus rotation of the handle (40) and the lead-screw (36), will cause the clamp members to move outwardly or inwardly between an open position and an operative position as shown in Fig.1 engaging or gripping a work piece such as the plank (11) as it rests on the top surface of the beam (30) of the support member (12).

The clamp members (34) are provided with flat upper surfaces (42) so that when they are in an open position they can provide a support for a wide flat item which is too wide to go between the clamp members (34) when they are in their fully open position.

The beam (30) may comprise folded sheet metal, a moulding or an extrusion. The clamp members (34) are preferably formed of a synthetic plastics material, by for instance injection moulding, and the plastics material is preferably chosen to be self lubricating on the beam (30) and the lead-screw (36). The mounting brackets (31) are also preferably formed from a suitable synthetic plastics material, by for instance injection moulding, as is the handle (40). The clamp members (34) and the mounting brackets (31) and the handle (40) may also be formed of metal by for instance forging or casting if this is preferable in particular manufacturing circumstances. The leg assemblies (14,15) are preferably formed from round cross section tubular steel but may if desired by of square cross section or may be formed from light alloy.

Thus it can be seen that the embodiment provides an improved work support in the form of a trestle with means to locate and engage or grip a work piece resting on the support member (12) thereof. Further the work piece will be centred on the support member (12) by the symetrical action of the lead screw (37). The support structure (13) may be folded so that the whole trestle is reduced to a flat item for storage as indicated in Fig.3, where the embodiment of Fig.1 is shown hanging from two pegs (50) on a wall, in its folded condition. The leg assembly (15) folds to lie within the leg assembly (14). It can be seen in use that the lead screw (36) lying inside the cross section of beam (30) is protected from dirt or swarf falling from any operation on a work piece in use, leading to continued free and reliable operation of the clamps (34).

It can be seen that the embodiment described may also be used to support and clamp a working platform in cooperation with another such trestle to provide a working platform spaced above the ground.

While the above description has been directed to an embodiment of the invention in the general form of a trestle, it will be appreciated that any other foldable, or rigid support structure may be provided to support the beam (12) above the ground whilst still offering the main features of the invention.

Claims

1. A work support comprising a single work support member; means to support the work support member above the ground; and clamp means associated with the support member, arranged to engage or grip a work-piece when it is resting on the support member.

2. A work support in the form of a trestle comprising a clamp means arranged to engage or grip a work-piece when it is resting on the work support member of the trestle.

3. A work support in the form of a support member with associated clamp means arranged to engage or grip a workpiece when it is resting on the support member.

4. A work support as claimed in claims 1, 2 or 3, in which the support member is of inverted U shaped or channel cross-section.

5. A work support as claimed in any preceding claim in which the upper surface of the support member is rounded in cross-section.

6. A work support as claimed in any preceding claim, in which said clamp means comprises a pair of spaced clamp members at least one of which is movable along the support member between an open position and an operative or clamp position to engage or grip a work-piece resting on the support member.

7. A work support as claimed in claim 6, in which both said clamp members are movable along the support member.

8. A work support as claimed in claims 6 or 7, in which both said clamp members are arranged to move equally in opposite directions along the support member between said positions so that a work-piece is always clamped centrally on the support member.

9. A work support as claimed in claims 6, 7 or 8, in which the clamp means includes manually operable means to move such clamp member or members between said positions.

10. A work support as claimed in any one of claims 6 to 9 in which the clamp means includes a lead-screw having portions of appropriate handed thread, and each of the clamp members is in screw-threaded engagement with a respective handed portion of the lead-screw.

11. A work support as claimed in claim 10, including a handle at the side of the work support by means of which the lead-screw may be operated to move the clamp members.

12. A work support as claimed in claims 10 or 11, in which the lead-screw is disposed within the cross-section of the support member.

13. A work support as claimed in claims 10, 11, or 12, in which the lead-screw is carried in journal bearings disposed one at each end of the support member, and on a thrust bearing arrangement provided at one or both ends of the support member to axially locate the lead-screw relative to the support member.

14. A work support as claimed in any one of claims 6 to 13 in which the one or each clamp member is slidably mounted on the support member for movement along the support member, while being located on the support member against rotation about the support member.

15. A work support as claimed in any one of claims 6 to 14, in which the one or each clamp member is formed with an aperture corresponding in shape to the cross-section of the support member, the one or each clamp member being arranged to slide along the support member by means of such aperture.

16. A work support as claimed in any one of claims 6 to 15, in which said clamp members are formed with flat surfaces to provide a support face for a flat work-piece which is too wide to fit between the clamp members in their fully open position.

17. A work support as claimed in any preceding claims, in which means provided to support the support member above the ground comprises a foldable support structure.

18. A work support as claimed in claim 17, in which said support structure is adjustable in height.

19. A work support as claimed in claims 17 or 18, in which said support structure comprises two leg assemblies at least one of which is pivotally mounted on or adjacent the support member.

20. A work support as claimed in claim 19, in which each said leg assembly comprises a pair of legs extending from the support member to the ground and connected by a base member arranged to lie on or immediately adjacent the ground.

21. A work support as claimed in claims 19 or 20, in which the support member is rigidly attached to a first of such leg assemblies, while the second leg assembly is pivotally mounted on the first leg assembly about an axis which lies adjacent the support member.

22. A work support as claimed in claim 21, in which said second leg assembly is arranged to fold to lie within the first leg assembly in a closed or storage position.

23. A work support as claimed in any one of claims 19 to 22, in which each such leg assembly is provided with a pair of ground engaging feet.

24. A work support as claimed in any one of claims 19 to 23, in which latch means is provided to locate the leg assemblies relative to each other in a position to support the support number above the ground.

25. A work support as claimed in claim 24, in which said latch means is arranged to locate the leg assemblies at a chosen one of a number of possible relative angles.

26. A work support substantially as herein described with reference to the accompanying drawings.