TITLE: CLAMP

FIELD OF THE INVENTION

This invention concerns fabrication tools.

BACKGROUND OF THE INVENTION

Fabricators are accustomed to building up complex structures by fastening components together. Fabrication makes use of jigs and clamps which hold components in the

required positions while drilling, rivetting, welding and other joining techniques are performed. Where two planar surfaces must be superimposed, the joining step is straightforward because the opposed clamp faces are planar and parallel, but when a part such as an angle, pipe, channel or box section is involved, the maintenance of the parts in the selected positions is a problem. Much time is wasted in coping with support problems which prior art clamps were not designed to overcome.

US PatentNo.2,108,077 discloses apipejoint welding clamp 10 for holding two sections of pipe 11, 12 in adjoining positions while they are being welded together. This type of clamp 10 is not commonly known in the field. The clamp 10 comprises a long angle iron 14 in which the pipe sections 11, 12 are to be placed, a pair of yokes 20 which are hingedly attached to one side of the angle iron 14, and a pair of clamping bolts 25 passing through respective yokes 20. The angle iron 14 defines a V-notch 15 which allows access to the joining line 16 between the pipe sections 11, 12. The clamping bolts 25 have buttons 27 adapted to contact with pipe sections 11, 12 and hold them in the angle iron 14 so as to allow the joint line 16 to remain secure whilst being accessed through the V- notch 15 and welded together.

Whilst this prior art clamp 10 may be suitable for welding two sections of pipe end to end, it is quite bulky to be carried around in a tool kit, and relatively complex to manufacture. Furthermore, it does not address the problem of securing two superimposed components with non-planar surfaces together for welding.

hi US Patent No. 5, 135,209 there is disclosed a pipe clamp apparatus 10 adapted to hold a first pipe P(I) end to end with a second pipe P(2) at junction J. This type of clamp is not commonly known in the field. The pipe clamp apparatus 10 comprises a central shank 12 with a first leg 13 and first threaded bore 15 extending from one end of the shank 12, and a second leg 14 and second threaded bore 16 extending from the other end of the shank 12. A threaded rod 23 with V-shaped bracket 24 is attachable to the first threaded bore 15. Another threaded rod 20 with a handle 22 at one end and a plate 21 at the other end passes through the second threaded bore 16. Another V-shaped bracket 31 is attachable to the plate 21 of the threaded rod 20 via a tubular socket 38. The V-shaped brackets 24, 31 define semicircular recesses 29, 30 and 36, 37 which allow access to the

pipe junction J for welding when the brackets 24, 31 are brought together around the pipes P(I), P(2).

Whilst this prior art pipe clamp apparatus 10 may be suitable for holding two small and light pipe sections end to end, it does not address the problem of securely holding two components superimposed together for welding, wherein at least one of those components is non-planar. This apparatus 10 would be impractical for securing heavy non-planar components (such as those used in a crane) together in a superimposed arrangement due to its various adjustable and removable parts making it relatively unsturdy and imprecise. The removable and adjustable parts also make it more complex to manufacture and less user friendly.

The invention will be described with particular reference to stiffening crane components, but persons skilled in the art will recognise other applications as the specification proceeds.

SUMMARY OF THE INVENTION

In one aspect the invention provides a G-clamp comprising, a unitary body having a static clamp face, a screw passing through the unitary body, and a pad disposed about one end of the screw with a movable clamp face, wherein the static clamp face comprises a V-notch which is V-shaped in section for locating curved or angled surfaces of a component thereby stabilising the component for clamping together with another superimposed component.

Another apparatus aspect of the invention comprises a clamp comprising,

a unitary body having a static clamp face, wherein the static clamp face is V- shaped in section so as to form a V-shaped cradle adapted to contact curved or angled surfaces of a component in order to locate and stabilise the for clamping together with another component, and

- A - pressing means having a movable clamp face which is movable towards and away from the static clamp face, the pressing means being adapted to press and hold the other component against the component in the cradle.

The angle of the V-shaped notch may be 70-160°. More particularly it may be 90-140°. In a particular form it may be substantially 90°.

The moveable clamp face may be substantially flat. Alternatively, the movable clamp face may be V-shaped.

The pad may comprise a v-notch. The V-notch may form a valley which runs from edge to edge of the pad. The valley may run in a substantially straight line. It may pass through the centre of the pad.

The angle of the V-notch of the pad may be 70-160°. More particularly it may be 90- 140°. The pad may comprise a pair of V-notches. They may intersect substantially perpendicularly at the centre of the pad. The angles of the V-notches may be different. In a particular form the angle of one V-notch of the pad is substantially 90° and the angle of the other V-notch of the pad is substantially 140°.

The pad may be adjustable so that either of the V-notches of the pad can be suitably aligned with the superimposed component. For instance the pad may be rotatable or swivelable on a ball on the end of the screw.

The pressing means may comprise a screw passing through the body and a pad disposed about one end of the screw. The moveable clamp face may form part of the pad opposite the static clamp face.

The pad may be exchangeable enabling a choice of a flat pad or a right angle pad or pads with different V-angles .

The clamp may comprise a snap ring which enables a user to apply the pad to and detach the pad from a ball on the end of the screw.

In another aspect the invention provides a G-clamp, wherein the static clamp face defines a V-notch for locating curved or angled surfaces of a component thereby stabilising the component during clamping together with another superimposed component. A table may be mountable on the V-notch in order to alter the shape of the static clamp face.

Another apparatus aspect of the invention provides a fabrication tool comprising a clamp with opposed faces, wherein at least one of the faces is V-shaped in section.

The angle of the V-shaped section may be 90-140°. The clamp may have a static clamp face and a moveable clamp face. One or both of the faces may be V-shaped in section. The moveable clamp face may be a pad at the end of a screw as in a G clamp. Instead the moveable clamp face may be a pad on a sliding assembly such as a sash clamp.

In another version the moveable clamp face may be a pad on a pneumatic or hydraulic clamp but the latter are more suited to static clamping devices in a workshop, whereas the invention is particularly suited to portable use on static workpieces such as a tower crane at a construction site, or workpieces which are heavy and inconvenient to move about.

For some work it is sufficient if one of the clamp faces is V-shaped in section. This will form a supporting seat for angle iron and pipes. If the clamp body is a casting, the surface may be incorporated during the casting stage. The surface may be protected with a V-section lining which can be replaced if damaged. Such a clamp may have a lead screw with a conventional flat pad for urging the workpiece against the V-shaped cradle in the static clamp face. This arrangement easily squeezes a channel workpiece straddling a pipe with the longitudinal upstands of the channel contacting the cylindrical wall of the pipe leaving the contact areas accessible for welding.

The ball and socket in the pad and lead screw allow small angular adjustment to suit the operator and accurate positioning is possible, whereafter the selected position is preserved by applying screw pressure. The pad of the moveable clamp face may be exchangeable enabling a choice of pads with different V-angles. Accordingly a shallow, flat or right angle pad can be selected for the job in hand. The pad's socket may have a

snap ring which enables the user to apply and detach the pad to the ball on the end of the screw.

The moveable clamp pad may be V-shaped in section. This is useful if box section components are to be held by the clamp. In such a clamp both clamp faces are V-shaped in section. In fabrication work it is useful to be able to clamp components together of differing cross section so that one braces the other and it is important that when the clamp applies pressure the initial position of the superimposed parts does not change. One clamp face may have wide angle while the opposing clamp face has a narrower angle.

This arrangement works effectively when the screw pad is of shallow angle and the static pipe pad is substantially 90°.

The clamp body may be conventional, that is semi-circular but may instead be looped to accommodate workpieces of different shape, for example plates or sheets . The body may have parallel faces in order to be gripped in an engineers vice. Steel is the preferred material but as relatively small forces suffice to keep the workpieces in place during fabrication, lighter alloys and aluminium are feasible.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments of the invention are now described with reference to the accompanying drawings, in which:

Figure 1 is a side view of the clamp.

Figure 2 is a front view of the clamp of Figure 1.

Figure 3 is a side view of the clamp of Figure 1 urging the upstands of a channel and the outer surface of a pipe together.

Figure 4 is a side view of the clamp of Figure 1 urging together a flat plate and an angle member.

Figure 5 is a side view of a variant clamp urging a pipe into the valley of an angle member.

Figure 6 is a side view of a further variant clamp urging together a pipe and a pair of angle members.

Figure 7 is a front view of the clamp and workpieces of Figure 6.

Figure 8 is a side view of the variant of Figure 6 urging a square tube into the valley of an angle member.

Figure 9 is a section through a portion of the screw and a pad showing the exchange modification.

Figure 10 is a side view of another variant clamp urging a pipe into the valley of an angle member.

Figure 11 is a front view showing the clamp visible in Figure 10 as well as another clamp of this type and the workpieces of Figure 10.

DETAILED DESCRIPTION WITH RESPECT TO THE DRAWINGS

Referring now to Figures 1 and 2, the clamp 1 comprises a unitary semi-circular clamp body 2 of T-section being a steel casting. The body 2 is 15mm thick with a clamp table 4 disposed at 90° to the body and at its widest being 52mm across at the support end 6 and somewhat narrower at the screw mount end 8. Between the ends the body deepens to about 100mm, whereas the depth at the ends is about 85mm. A conventional buttress thread screw 10 carries a conventional screw pad 12. The screw is 24mm in diameter and the pad is 50mm in diameter. The pad lies in register with a V-notch 14 in the table which extends into the clamp body. The table is 8mm deep and the V-notch is 40mm deep. Accordingly the sides 16 of the V-notch are 45mm long. The clamp throat marked H is 142mm.

In Figure 3 the usefulness of the V-notch is apparent in that a 114mm diameter pipe 18 seats in the V-notch while circular pad 12 engages the floor of an inverted 100 x 50mm channel 20. Once the pipe and channel are placed as shown between the pad and V- notch, the pad 12 can be screwed toward the channel and tightened against the channel 20 progressively with no movement of either pipe or channel. The space 22 between the upstand and the cylindrical surface of the pipe 18 remains accessible for welding.

In Figure 4 a large angle iron 40 measuring 200 x 200 x 26mm is just accommodated in the throat of the clamp and is braced by a 200 x 25mm section plate 42. The pad nips the plate and angle iron together while welds are applied. The body 2 may be gripped at a suitable angle in an engineers vice.

For some applications such as joining a pipe in the valley of an angle member as shown in Figure 5. Here the pad 12 is not flat but is ground to create a 140° pad notch 44. As the pad is 50mm in diameter the pad successfully holds a 100mm pipe 18 in the valley of 150 x 150 x 16mm angle iron 40.

In Figures 6 and 7 the pad shape is different in that it has a conical stem 60 and an integral table 62 of inverted V-section. The vertex of the inverted V-section table and the vertex of the V-notch 14 in the clamp are colinear so that the two define a rectangular space between them. This is shown occupied by a pipe 18 partially surrounded by a pair of angle members 40.

In Figure 8 the same pad 60/62 is shown holding a square 100 x 100 x 6mm box section tube 64 against a 150 x 15 x 16mm angle member 40. The table 4 is detachable being held by a screw 66. Table 4 is exchangeable for a prism shaped table which is held in position by the same screw 66. The prism shaped table may be quadrangular in section in order to convert the clamp to a clamp with parallel reaction surfaces. Tables of other shapes may also be used such as a table with a V-sectioned base for fitting into the V- notch and a convex sectioned top for supporting a concave surface.

In Figure 9 the socket bore 90 in the conical part of the pad 12 has a circumferential groove 92 which houses a circlip 94. The clip flexes when the ball 96 is pushed into the

socket. Likewise when the pad is pulled off the screw the circlip again flexes over the ball and releases the pad. The exchange facility thus extends to all the pads if required.

Figures 10 and 11 show another variant clamp in which the pad 12 has a pair of first and second V-notches, 98 and 100 respectively, ground into what is otherwise a flat pad. The valleys of the respective V-notches, 98 and 100, run from edge to edge of the pad in a straight line, intersecting perpendicularly through the centre of the pad. Thus the pad is arranged with four flat quadrants 104 divided by the two V-notch valleys 98, 100 running at right angles.

The first V-notch 98 forms an angle of 140° which may be more suited for contacting the rounded surfaces of a pipe 18, whereas the second V-notch 100 forms an angle of 90° which may be more suitable for contacting the angled surface of an angle iron 40. The pad 12 is adjustable by swivelling on the ball 96 in order to suitably align the desired V- notch, 98 or 100, with the superimposed workpiece.

Figure 11 shows how two clamps may be used side by side in order to join two sections of pipe 18 end to end by welding 102, and then weld the joined pipe 18 to an angle iron 40.

We have found the advantages of the above embodiment to be:

1. The clamp stabilises and holds components with non-planar surfaces such as pipes, angle irons, plates, box sections, and channels of various shapes and sizes in position so that they may be welded together.

2. The clamps retain the compactness and portability of the prior art clamps and can therefore be taken to the job.

3. The speed of application to clamp two or more workpieces together saves labour. The clamps work just as well on timber and plastic components where adhesive and sealants may be applied during fabrication.

4. The positive reliable contact between contacting surfaces gives the operator confidence so that if the job is bumped or a tool falls on it accidentally or the heat of the welding stage tends to move the components, the components will stay in the clamped positions selected by the operator.

5. As metal components such as rods, tubes, angles and strip are manufactured in standard sizes all over the world, the clamps can be made in a small range of sizes.

The illustrations, photographs and drawings, if any, form part of the disclosure of this specification as does the description, illustrations, photographs and drawings of any associated provisional or parent specification or of any priority document, if any, all of which are imported hereinto as part of the record hereof.

Finally it is to be understood that various alterations, modifications and/or additions may be incorporated into the various constructions and arrangements or parts without departing from the spirit and ambit of the invention. For example while the V-notch is useful for an engineering fabrication of robust sections of metals it is amenable to smaller scale work such as fabrication of medical apparatus and yet smaller such as jewellers work.

For some such applications a V-notch may not be the best choice and a concave pad may achieve a better result. In extreme cases a channel section pad may be effective when used with a V-notch table or vice versa. These are regarded as variants of a V-notch because they stabilise the workpieces and do not yield when clamping pressure rises.