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Patent Searching and Data


Title:
DOUBLE ACTION SCISSOR CLAMP
Document Type and Number:
WIPO Patent Application WO/2009/092136
Kind Code:
A1
Abstract:
A clamp comprises a pair of elongate members, two pairs of scissor links pivoted to opposite ends of the members with blocks as their fulcrums, one of said blocks acting as a stop for clamped items and the other carrying a compression device for urging said items towards the stop. The elongate members are RHS sections, the scissor links are a pair of elongate plates with holes in opposite ends and the compression device is a screw..

Inventors:
HUTTON, David, Lorrimore (152 Fairneyview-Fernvale Road, Fernvale, Queensland 4306, AU)
HUTTON, Judith (152 Fairneyview-Fernvale Road, Fernvale, Queensland 4306, AU)
Application Number:
AU2009/000071
Publication Date:
July 30, 2009
Filing Date:
January 23, 2009
Export Citation:
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Assignee:
HUTTON, David, Lorrimore (152 Fairneyview-Fernvale Road, Fernvale, Queensland 4306, AU)
HUTTON, Judith (152 Fairneyview-Fernvale Road, Fernvale, Queensland 4306, AU)
International Classes:
B25B5/00; B25B11/00; E04F15/00; E04F21/20; F16B2/00
Foreign References:
US4671500A1987-06-09
US5356124A1994-10-18
DE8717385U11988-04-21
Download PDF:
Claims:

CLAIMS

1. A clamp comprises a pair of elongate members, two pairs of scissor links pivoted to opposite ends of the members with blocks as their fulcrÏ…ms, one of said blocks acting as a stop for clamped items and the other carrying a compression device for urging said items towards the stop.

2. The clamp of claim 1 wherein the elongate members are hollow sections.

3. The clamp of claim 1 wherein the scissor links are a pair of elongate plates with holes in opposite ends.

4. The clamp of claim 1 wherein the compression device is a screw.

5. A clamp as herein described with reference to the accompanying drawings.

Description:

DOUBLE ACTION SCISSOR CLAMP

FIELD OF INVENTION

This invention relates to wood working clamps and in particular clamps for planking timber together to construct furniture or to secure planks for gluing or nailing.

BACKGROUND OF THE INVENTION

Many different methods and devices have been used to clamp floor boards tightly together so that when they are glued or nailed they abut closely without any gap between boards. The most basic method is to fix the first board and then to manually push the next board hard up against the first. An early improvement on this manual pressure technique are the tongs disclosed in GB 302078 which force boards together with handles which have a locking device operated at the point of maximum compression.

One of the earliest devices used for floor boards, disclosed in GB 217767, is a flat triangular frame having legs at each corner of the triangle for gripping a beam. A wedge is then driven between between the frame and the floorboards forcing the latter together. GB 165653 discloses a U shaped piece of metal adapted to straddle a joist and a metal double wedge pivoted to it and a wooden wedge engagaing a rabbeted edge of the metal wedge. The cramp is operated by driving the wooden wedge to force the boards together.

GB 190929198 shows a cramp with a foot plate fixed to the joist by spikes and a racked pusher plate operated by a lever which has a pawl for locking when the boards are compressed. GB 190700428 also has a rack mounted on a base plate and engaged by a toothed sector which is operated by a lever taken into a socket on the sector. A pawl prevents backward motion of the rack when the boards are compressed.

A complicated screw operated device is shown in GB 606741 but the most commonly used device is a simple elongated vice the jaws of which grip the boards and are drawn together by a long screw. GB 205965 discloses a device with a screw and a double scissor action similar to a common form of car jack, which is used to urge boards together prior to nailing.

However all these methods and devices have a number of disadvantages. Those with complex mechanisms are costly to manufacture and prone to failure while the simpler devices require considerable manual force and are difficult for one person to operate. All of the prior art is also prone to having the clamped boards buckle under pressure thus making it difficult to glue and/ornail them in a tight planar configuration.

OBJECT OF THE INVENTION

It is therefore an object of the present invention to provide a simple clamp which is easy to manufacture and which overcomes the disadvantages of the prior art, or at least provides a useful alternative.

STATEMENT OF THE INVENTION.

According to the present invention, a clamp comprises a pair of elongate members, two pairs of scissor links pivoted to opposite ends of the members with blocks as their fulcrums, one of said blocks acting as a stop for clamped items and the other carrying a compression device for urging said items towards the stop.

Preferably the elongate members are hollow (RHS) sections.

Preferably the scissor links are a pair of elongate plates with holes in opposite ends.

Preferably the compression device is a screw.

Alternatively the compression device is a pneumatically operated ram.

Alternatively the stops have cushion devices which protect the edges of the clamped boards.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig 1 is an isometric view of a clamp with boards clamped in situ from beneath Fig 2 is an elevation of the clamp in Fig 1 Fig 3 is a side elevation of an open clamp Fig 4 is a plan view of the clamp of Fig 3 Fig 5 is an end elevation from the left and Fig 6 is an end elevation from the right

DETAILED DESCRIPTION OF THE INVENTION The clamp shown in Figs 1 to 6 is constructed from two rectangular RHS sections 1 which have a series of holes 2 for locating links 3. Pivots 4 pass through links 3 and sections 1 and pivots 5 secure the other ends of links 3 to blocks 6 and 7 thus forming a double action scissor mechanism. Links 3 are pivoted to block 6 with a single pivot but are pivoted to block 7 at two pivot points.

Block 6 acts as the stop at one end of the clamp and block 7 has a threaded hole through its centre between pivot points to carry screw 8 of the clamp which is turned by handle 9 and has stop 10 rotatably mounted on its free end. Accordingly when the clamp is assembled with boards between stops 7 and 10 and handle 9 is turned screw 8 urges the boards together and sections 1 clamp down on the boards to stop them buckling. Feet 11 support the clamp in an upright position when in use.

The series of holes 2 allow adjustment of the clamp to accommodate different numbers of boards. Different lengths of RHS section 1 can be provided for jobs

from gluing long spans of planked timbers to gluing or nailing shorter panels for example to make doors from strip timber.

Stops 7 and 10 can be changed to accommodate different gripping devices suitable for a variety of jobs, for example stops 7 and 10 may carry rubber cushions shaped so as not to damage tongue and groove boards. Further screw 8 could be replaced by an hydraulically or pneumatically operated ram.

VARIATIONS

It will be realized that the foregoing has been given by way of illustrative example only and that all other modifications and variations as would be apparent to persons skilled in the art are deemed to fall within the broad scope and ambit of the invention as herein set forth. For example various mechanical equivalents could be substituted for the channel, link, pivot and screw components without departing from the inventive concept.

Throughout the description and claims to this specification the word "comprise" and variation of that word such as "comprises " and "comprising" are not intended to exclude other additives components integers or steps.