GB2425982A

GB2425982A - Clamp

Info

Publication number: GB2425982A
Application number: GB0509581A
Authority: GB
Inventors: Robert Harland Games
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-05-11
Filing date: 2005-05-11
Publication date: 2006-11-15
Anticipated expiration: 2025-05-11
Also published as: GB0509581D0; GB2425982B

Abstract

A clamp 10 comprises a guide member 12, a first jaw 14 fixed relative to the guide member 12, a second jaw 16 movable relative to the guide member, and a drive shaft 26, 28 adapted to transfer drive from a powered rotary tool (30, Fig 5) to the clamp 10 for moving the second jaw 16 relative to the first jaw 14. The second jaw 16 may be in threaded engagement with a threaded rod 24 disposed axially inside the guide member 12 so that rotation of the drive shaft 26, 28 by the powered rotary tool (30. fig 5) causes the second jaw 16 to move along the threaded rod 24. The apparatus 10 may also be used as a tool guide.

Description

Title: Clamp The present invention relates to a clamp, and more

particularly but not exclusively to a clamp for use in woodworking.

Background

Conventional sash clamps, for example flat bar clamps and pipe clamps, are commonly used in the assembly of furniture, when gluing up. A typical workshop sash clamp is between 300mm and 1270mm in length, is heavy and cumbersome and slow to operate. Lightweight materials and quick release levers have gone some way to mitigating these problems. However there is a need to provide a sash clamp, which is capable of clamping with a force comparable with conventional sash clamps, and can be used as a guide, for example, in marking out and for guiding power tools. This has not been achieved to date by a single action cam lock arrangement because the clamping force generated by a cam, for example a rotary cam moved through a small angle ie between 90 and 1800, is typically not sufficient to pull up a glued joint effectively. There is also a need to provide for quick and easy operation of the clamp.

Summary of the Invention

According to the present invention there is provided a clamp comprising a guide member, a first jaw fixed relative to the guide member, a second jaw movable relative to the guide member, and at least one drive transfer means adapted to transfer drive from a powered rotary tool to the clamp for moving the second jaw relative to the first jaw.

It is an advantage of the invention that by powering the second jaw by means of a powered rotary tool, the clamp can be operated quickly and easily. Furthermore, the clamp can be tightened to a degree determined, in part, by the powered rotary tooL Preferably the or each drive transfer means is a drive shaft.

Preferably the drive shaft has a hexagonal cross-section.

Preferably the hexagonal cross-section is sized to be received in a standard bit holder, such as a magnetic bit holder. Preferably the drive shaft is 5mm diameter across opposed flats of the hexagon.

The or each drive shaft may have a female socket for receiving a hexagonal drive bit.

The socket may be between 5mm and 13mm across opposed flats. Preferably the socket is 8mm across opposed flats.

The drive shaft may have means for receiving a screw driver bit, for example a star drive, straight blade, hexagon drive bit, cruciform drive bit or other drive bit.

A further hexagon drive element of larger diameter may be disposed concentrically about and connected to the drive shaft.

The further hexagon is preferably 13mm diameter across the flats, and may be engaged by a 13mm spanner.

Alternatively the drive transfer means is a drive shall of any cross section suitable for being driven by a powered rotary tool, such as a battery powered screwdriver or drill.

The drive shaft may be coated with titanium nitride or other hard wearing surface coating.

Preferably the guide member has a substantially rectangular or square cross-section, with a longitudinal aperture extending along one side thereof, to provide an open side allowing access to the interior of the guide member.

Alternatively the guide member may have a U-shaped cross section. The open side of the U-section allows access to the interior of the guide member.

The guide member is advantageously substantially flat on all of its four longitudinal surfaces. This enables the guide member to be placed against flat surfaces being clamped, and on a flat working surface, e.g. a work bench.

Preferably a threaded rod is disposed axially inside the guide member, and extends from one end of the guide member to the other.

An end cap is preferably provided at each end of the guide member.

The threaded rod is preferably journalled into each end cap and is free to rotate relative to the guide member and the end caps.

Preferably a first said drive transfer means is connected to one end of the threaded rod, and a second drive transfer means is connected to the other end of the threaded rod. Consequently, rotation of either the first or second drive transfer means, causes rotation of the threaded rod.

Preferably the first jaw extends perpendicularly from a distal end of the guide member, from the open side of the guide member. The first jaw may be made integral with one of the end caps.

Preferably the second jaw is in threaded engagement with the threaded rod, rotation of the threaded rod causing axial movement of the second jaw along the threaded rod.

The second jaw preferably extends from the open side of the guide member.

Preferably the sides of the first and second jaws extending beyond the open side of the guide member lie in the same planes as the sides of the guide member.

This provides the advantage that the clamp guide can be used for transferring markings from the side edges of a board to its major faces when marking out.

Preferably an aperture is provided through each jaw, through which a fixing can pass for attaching a wooden block or other member to each jaw. This provides the facility to be able to increase the size of the jaws, in order to reduce the clamping pressure, and thereby reduce the risk of damaging a wooden surface being clamped.

The or each drive transfer means may include an adjustable ratchet, which transfers drive from the or each drive shaft to the threaded rod. The ratchet may be adjusted to set the clamping force.

According to a further part of the invention there is provided a tool guide comprising a guide member, a first jaw fixed relative to the guide member, a second jaw movable relative to the guide member, and at least one drive transfer means adapted to transfer drive from a powered rotary tool to the tool guide for moving the second jaw relative to the first jaw.

Brief description of the drawings

The invention will now be described by way of example with reference to and as illustrated in the accompanying drawings, in which: Fig 1 shows a schematic perspective view of a clamp guide in accordance with the invention; Fig 2 shows a plan view from above of the clamp guide of Fig 1; Fig 3 shows a plan view from below of the clamp guide of Figs 1 and 2; Fig 4 shows a side view of the clamp guide of Figs ito 3; and Fig 5 shows a schematic perspective view of the clamp guide of Figs 1 to 4 being used in the manner of a sash clamp to clamp a number of wooden boards being jointed.

Detailed description of specific embodiments

Referring firstly to Figs I to 4, a clamp is indicated generally at 10. The clamp 10 comprises a guide member 12, a first jaw 14 and a second jaw 16. The guide member 12 is straight, and is preferably made from extruded aluminium or other lightweight material. The guide member 12 has a substantially square cross-section with a longitudinal aperture 18 extending along one side thereof, as shown in Fig 3.

A first end cap 20 is disposed at one end of the guide member 12, and a second end cap 22 is disposed at the other end of the guide member 12. The second end cap 22 is retained within the guide member extrusion, but the other end cap 20 extends beyond the extrusion on the side of the aperture 18 to form the first jaw 14. The end caps 20, 22 are rigidly fastened to the guide member, by mechanical fasteners and/or adhesive.

A threaded rod 24 is disposed axially inside the guide member 12, and extends from one end of the guide member to the other. The threaded rod 24 is joumalled into each end cap 20,22 and is free to rotate relative to the guide member 12 and the end caps.

A hexagonal drive shaft 26 is connected to one end of the threaded rod, and a second hexagonal drive shaft 28 means is connected to the other end of the threaded rod. The drive shafts 26, 28 extend substantially centrally from each end of the guide member and can be driven by a powered rotary tool, such as a battery powered screwdriver 30 shown in Fig 5, or a drill. Rotation of either the first or second drive shafts 26, 28, causes rotation of the threaded rod.

The hexagonal cross-section drive shafts are sized to be received in a standard bit holder, including a magnetic bit holder. Preferably the drive shaft is 5mm diameter across opposed flats of the hexagon. The ends of the drive shafts are also provided with drive engaging means, for example, for receiving a star drive, straight blade, cruciform drive bit, hexagon drive bit or other drive bit.

A further hexagon drive element (not shown) of larger diameter may be disposed about and connected to the drive shafts 26,28. Each further hexagon is preferably 13mm diameter across the flats, and may be engaged by a 13mm spanner. The drive shafts are coated with titanium nitride or another hard wearing surface coating.

The second jaw 16 is in threaded engagement with the threaded rod 24, and in use, rotation of the threaded rod causes axial movement of the second jaw along the threaded rod.

The sides of the first and second jaws 14,16 extending beyond the aperture 18 in the guide member lie in the same planes as the sides of the guide member 12. This provides the advantage that the clamp 12 can be used for transferring markings from the side edges of a board to its major faces when marking out. In other words, each jaw 14,16 forms a right angle with the guide member 12, as viewed in Fig 4, which can be used for alignment of the clamp in use.

Apertures 32,34 are provided through each jaw 14,16, through which a fixing can pass for attaching a wooden block or other member to each jaw. This provides the facility to be able to increase the contact area of the jaws, in order to reduce the clamping pressure on surfaces being clamped. This reduces the risk of damaging, for example, a wooden surface being clamped.

In use, as shown in Fig 5, a clamp 10 can be rested across a number of boards 36,38,40 to be clamped. The battery powered screwdriver 30 is engaged with the drive shaft 28. Rotation of the drive shaft 28 in a first direction, indicated by arrow A, causes the second jaw 16 to traverse along the threaded rod 24, until the jaw 16 engages the edge of the outer board 40. The screwdriver 30 then tightens the jaws 14,16 as desired. A ratchet on the screwdriver may control the clamping force.

Rotation of the drive shaft in the other direction causes the jaw 16 to move in the other direction, thereby releasing the boards 36,38,40 from the jaws 14,16. The clamp can also be operated by rotation of the other drive shaft 26.

Because the surfaces of the clamp 10 are substantially flat and straight, the clamp can be used as a tool guide. A plurality of clamps can be used for supporting a workpiece being clamped. Clamps 10 placed side by side facing in opposite directions can be used to clamp a plurality of workpieces in a stack.

Claims

Claims 1. A clamp comprising a guide member, a first jaw fixed relative to

the guide member, a second jaw movable relative to the guide member, and at least one drive transfer means adapted to transfer drive from a powered rotary tool to the clamp guide for moving the second jaw relative to the first jaw.
2. A clamp as claimed in claim 1 in which the or each drive transfer means is a drive shaft.
3. A clamp as claimed in claim 2 in which the drive shaft has a hexagonal cross- section.
4. A clamp as claimed in claim 3 in which the drive shaft is 5mm diameter across opposed flats of the hexagon.
5. A clamp as claimed in any one of claims 2 to 4 in which the drive shaft has means for receiving a star drive, straight blade, hexagon or cruciform drive bit.
6. A clamp as claimed in any one of claims 2 to 5 in which a further hexagon drive element of larger diameter is disposed about and connected to the or each drive shaft.
7. A clamp as claimed in claim 6, in which the further hexagon drive element is 13mm diameter across the flats.
8. A clamp as claimed in any one of claims 2 to 7, in which the drive shaft is coated with titanium nitride.
9. A clamp as claimed in any preceding claim, in which the guide member has a substantially rectangular or square cross-section,, with a longitudinal aperture extending along one side thereof.
10. A clamp as claimed in any one of claims 1 to 8, in which the guide member has a U-shaped cross section.
11. A clamp as claimed in any preceding claim, in which a threaded rod is disposed axially inside the guide member, and extends from one end of the guide member to the other.
12. A clamp as claimed in any preceding claim, in which an end cap is provided at each end of the guide member.
13. A clamp as claimed in 12, when dependent on claim 11, in which the threaded rod is journalled into each end cap and is free to rotate relative to the guide member and the end caps.
14. A clamp as claimed in 13, in which a first of said drive transfer means is connected to one end of the threaded rod, and a second drive transfer means is connected to the other end of the threaded rod.
15. A clamp as claimed in any preceding claim, in which the first jaw extends perpendicularly from a distal end of the guide member.
16. A clamp as claimed in 15 when dependent on claim 13, in which the first jaw is integral with one of the end caps.
17. A clamp as claimed in 16, in which the second jaw is in threaded engagement with the threaded rod.
18. A clamp as claimed in 17, in which the second jaw preferably extends from the open side of the guide member.
19. A clamp as claimed in 18, in which the sides of the first and second jaws extending beyond the open side of the guide member lie in the same planes as the sides of the guide member.
20. A clamp as claimed in any preceding claim, in which an aperture is provided through each of the first and second jaws.
21. A tool guide comprising a guide member, a first jaw fixed relative to the guide member, a second jaw movable relative to the guide member, and at least one drive transfer means adapted to transfer drive from a powered rotary tool to the tool guide for moving the second jaw relative to the first jaw.
22. A clamp or tool guide substantially as described herein with reference to and as ifiustrated in Figs 1 to 5 of the accompanying drawings.