Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
CLAMPING DEVICE AND METHOD OF USING
Document Type and Number:
WIPO Patent Application WO/2019/111100
Kind Code:
A1
Abstract:
A non-scissor action four-way clamp which includes a primary portion and a secondary portion; the primary portion including two opposed primary jaws at least one of which is movable in relation to the other, and one movable secondary jaw; the secondary portion including one movable secondary jaw which is opposed to the other secondary jaw; the secondary portion being attached to, and movable in relation to, said primary portion, or releasably attached to but completely disengageable from, said primary portion; wherein, in use, a line drawn between said two primary jaws intersects at right angles a line drawn between said two secondary jaws.

More Like This:
WO/2014/010391ELECTRIC CLAMP APPARATUS
Inventors:
CHIN ALLAN (NZ)
Application Number:
PCT/IB2018/059364
Publication Date:
June 13, 2019
Filing Date:
November 27, 2018
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
CHIN ALLAN (NZ)
International Classes:
B25B5/10; B25B5/00
Foreign References:
GB1048935A1966-11-23
US8226074B12012-07-24
US5513838A1996-05-07
US2366350A1945-01-02
US4691907A1987-09-08
US4753425A1988-06-28
Attorney, Agent or Firm:
BUCHANAN, Elspeth (NZ)
Download PDF:
Claims:
Claims:-

1. A non-scissor action four-way clamp which includes:

• a primary portion;

• a secondary portion;

• said primary portion including two opposed primary jaws at least one of which is movable in relation to the other, and one movable secondary jaw;

• said secondary portion including one movable secondary jaw which is opposed to the other secondary jaw;

• said secondary portion being either:

• attached to, and movable in relation to, said primary portion; or

• releasably attached to but completely disengageable from, said primary portion;

• wherein, in use, a line drawn between said two primary jaws intersects at right angles a line drawn between said two secondary jaws.

2. The clamp as claimed in Claim 1 , wherein said primary and secondary portions are releasably connected together by means of protrusions formed on said primary and secondary portions, said protrusions being releasably engageable to connect said primary and secondary portions together.

3. The clamp as claimed in Claim 1 , wherein said primary and secondary portions are connected together by means of a first connection which allows said primary and secondary portions to pivot relative to each other in the plane of said portions, and a second connection which releasably connects said primary and secondary portions together.

4. The clamp as claimed in Claim 1 , wherein:

• each of the primary and secondary portions is C shaped in plan and includes a base portion with two opposed arm portions substantially parallel to each other;

• each base portion and the corresponding arm portions lie in the same plane;

• each arm portion is secured to, or formed integrally with, the base portion at one end of the arm portion; and

• the other end of each arm portion is provided with means for connecting said primary and secondary portions together.

5. The clamp as claimed in Claim 4, wherein:

• each arm of the primary portion carries one of said primary jaws; and

• the base portion of each of said primary and secondary portions carries one of said secondary jaws.

6. The clamp as claimed in Claim 5, wherein each said secondary jaw is connected to the midpoint of the corresponding base portion.

7. The clamp as claimed in any one of Claims 4-6 wherein said means for connecting said primary and secondary portions together is selected from the group consisting of:

• a T-shaped protrusion formed at said other end of one of said primary and secondary portions and a complimentary T-shaped slot formed at said other end of the other of said primary and secondary portions;

· an internally threaded socket provided at said other end of one of said primary and secondary portions, an externally screw threaded pin dimensioned to be screw threadedly engaged with said socket, and a corresponding apertured portion provided at said other end of the other of said primary and secondary portions, said apertured portion being dimensioned to receive the corresponding pin therethrough.

8. The clamp as claimed in any one of Claims 4-7, wherein each jaw is mounted at one end of an externally screw threaded screw which is mounted upon the corresponding primary or secondary portion in an internally screw threaded hole, such that each jaw may be moved towards or away from the opposing jaw by rotation of the corresponding screw relative to the corresponding hole.

9. The clamp as claimed in any one of the preceding claims, wherein each jaw includes a swivel foot.

10. The clamp as claimed in any one of Claims 1-8 wherein three of said jaws include a swivel foot and the fourth jaw includes a fixed foot.

Description:
CLAMPING DEVICE AND METHOD OF USING

Technical Field

The present invention relates to a clamping device that includes 4 movable jaws and a method of using this clamp.

Background Art

On construction sites it is often necessary to attach material, sheets, beams, etc. to opposite sides of a column or beam at a specific position and orientation. The column or beam may be pre-drilled, but equally it may need on-site drilling. The normal way this is accomplished is the first piece of material is held against the column, often manually, then the position and orientation adjusted to that required. Once the desired position and orientation is achieved, a drill is inserted through the pre-drilled holes and the hole in the first piece of material created. The first piece of material is then removed and the second piece of material is held against the column or beam. Whilst the second piece of material is being held against the column or beam the position and orientation of this second piece of material is adjusted, the hole in the second piece of material is then drilled in the same manner as the first piece of material was. The first and second pieces of material are then attached to the beam or column, this may require the position and orientation of each piece of material is adjusted to that required before final attachment. This procedure sounds straight forward, but, the size and shape of the pieces of material can create handling and potentially safety issues. Without care, this method can also lead to the pieces of material being badly aligned this may compromise weather tightness, aesthetics or structural integrity; it can also lead to wastage as holes can be drilled in the wrong place.

Existing clamps

A standard G-clamp or C-clamp could be used, but the force is only applied by a single screw. With a single screw the clamping force holding the clamp to the column and the clamping force applied to the surface of the material cannot be independently set. In addition, when the second piece of material needs to be attached, the clamp needs to be loosened or removed to allow the second piece to be held, this means both pieces of material need to have their position and orientation in relation to the column set at the same time. This may necessitate the removal of the first piece of material to align and drill the second piece of material. Referring to Figure 1 a prior art 3-way clamp (1 ) is shown, said 3-way clamp (1 ) includes a frame (2), two opposed movable first jaws (3), each attached to a different associated first screw (4) and one movable second jaw (5) attached to an associated second screw (6). The longitudinal axis of the first screws (4) are parallel, in the configuration shown they are also coincident.

The frame (2) includes a base (7) and two arms (8), one arm (8) is attached to each terminal end of the base (7) and extends away from said frame (2) in the same direction. In the prior art version shown the base (7) and arms (8) are a single piece.

The frame (2) is shown as‘C’ shaped with the second screw (6) passing through the base (7) and extending in the same direction as the arms (8). The second jaw (5) is at the end of the second screw (6) within the interior of the‘C’.

3-way clamps are often used to attach edging material to doors, the second jaws (5) engaging with the faces of the door and the second jaw (5) used to hold the edging material against the edge of the door. 3-way clamps (1 ) can also be used to hold the facing material of a door onto the frame of the door.

Prior art 4-way scissor clamps (10), as shown in Figure 2, can also be used to apply both axial and trans-axial clamping at the same time, though these are normally used to clamp facing material to doors, or clamp a number of discrete elongate members together. These 4-way scissor clamps (10) have two frames (2) and one associated first screw (4), each with a first jaw (3); each frame (2) includes two centrally hinged sub-frames (1 1 ). Each sub-frame (1 1 ) that makes up one frame (2) co-terminates at a hinge joint (12) located close to, or where, the associated first screw (4) passes through the frame (2). The two frames (2) are linked together by shared second jaws (5). Each second jaw (5) is an elongate member extending between the two frames (2) that have essentially parallel longitudinal axis. In normal use the first jaws (3) engage with the edges of the work piece as the first screws (4) are wound in, applying an axial force to the workpiece (not shown) at the same time the second jaws (5) engage with the faces of the workpiece and apply a trans-axial force across the workpiece. These 4-way scissor clamps (10) may be able to be used to hold a first piece of material against a column and then a second piece of material, but they would necessitate aligning both pieces of material at the same time. This alignment of both pieces of material at the same time would be necessary as the second jaws (5) would have to be disengaged with the work to allow the second piece of material to be put in place. This form of clamp may also damage the edges of sheet material as the force is applied. A scissor action 4-way clamp (10) applies the force to the column or beam at the same time as the material; this means that whilst trying to adjust the position and orientation of the one or two pieces of material the clamp can move along the length of the beam or column. A scissor action 4-way clamp (10) is normally used to hold facing sheets onto a frame or to hold a plurality of elongate members against each other for gluing or otherwise fixing. The clamping action provided compresses the elongate members together whilst generating at least one planar face, a simultaneous duel face clamping action is achieved.

Any discussion of the prior art throughout the specification is not an admission that such prior art is widely known or forms part of the common general knowledge in the field. Nor does the existence of a piece of prior art suggest that there would be any motivation to use a particular device outside a particular use.

It is an object of this invention to provide a clamp which ameliorates one or more of the above deficiencies.

Disclosure of Invention

The present invention provides a non-scissor action 4-way which includes:

• a primary portion;

• a secondary portion;

• said primary portion including two opposed primary jaws at least one of which is movable in relation to the other, and one movable secondary jaw;

• said secondary portion including one movable secondary jaw which is opposed to the other secondary jaw;

• said secondary portion being either:

• attached to, and movable in relation to, said primary portion; or

• releasably attached to but completely disengageable from, said primary portion; wherein, in use, a line drawn between said two primary jaws intersects at right angles a line drawn between said two secondary jaws.

Preferably, said primary and secondary portions are releasably connected together by means of protrusions formed on said primary and secondary portions, said protrusions being releasably engageable to connect said primary and secondary portions together.

In one variant, said primary and secondary portions are connected together by means of a first connection which allows said primary and secondary portions to pivot relative to each other in the plane of said portions, and a second connection which releasably connects said primary and secondary portions together.

In a preferred embodiment of the invention, each of the primary and secondary portions is C-shaped in plan and includes a base portion with two opposed arm portions substantially parallel to each other; each base portion and the corresponding arm portions lie in the same plane; each arm portion is secured to, or formed integrally with, the base portion at one end of the arm portion; and the other end of each arm portion is provided with means for connecting said primary and secondary portions together.

Preferably, each arm of the primary portion carries one of the primary jaws; the base portion of each said primary and secondary portions carries one of said secondary jaws; and each secondary jaw is connection to the mid-point of the corresponding base portion.

In preferred embodiments of the invention, said means for connecting the primary and secondary portions together may consist of a T-shaped protrusion formed at said other end of one of said primary and secondary portions and a complimentary T-shaped slot formed at said other end of the other of said primary and secondary portions.

Preferably, said means for connecting said primary and secondary portions together includes an internally threaded socket provided at said other end of one of said primary and secondary portions, an externally screw threaded pin dimensioned to be screw threadedly engaged with said socket, and a corresponding apertured portion provided at said other end of the other of said primary and secondary portions, said apertured portion being dimensioned to receive the corresponding pin there through. Preferably, each jaw is mounted at one end of an externally screw threaded screw which is mounted upon the corresponding primary or secondary portion in an internally screw threaded hole, such that each jaw may be moved towards or away from the opposing jaw by rotation of the corresponding screw relative to the corresponding hole.

Each jaw may include a swivel foot. In another variant, three of said jaws include a swivel foot and the fourth jaw includes a fixed foot.

The invention further provides a method of using the non-scissor action 4-way clamp to attach pieces of material to a beam or column, that method is described in detail in the specification that follows. Variations on that method may be required to allow different embodiments of the non-scissor 4-way clamp to operate as required, these, it is believed, fall within the scope of one skilled in the art.

Brief Description of Drawings

By way of example only, a preferred embodiment of the present invention is described in detail below with reference to the accompanying drawings, in which:

Figure 1 is a plan view of a PRIOR ART 3-way clamp;

Figure 2 is a plan view of a PRIOR ART 4-way scissor clamp;

Figure 3 is a plan view of one variant of a non-scissor action 4-way clamp in assembled form;

Figure 4 is a plan view of one variant of the non-scissor action 4-way clamp in separated form;

Figure 5 is a plan view of a primary portion of the non-scissor action 4-way clamp;

Figure 5a is an end view of the primary portion of the non-scissor action 4-way clamp shown in Figure 5 in the direction of arrow a;

Figure 5b is an elevation view of the primary portion of the non-scissor action 4- way clamp shown in Figure 5 in the direction of arrow b;

Figure 5c is an elevation view of the primary portion of the non-scissor action 4- way clamp shown in Figure 5 in the direction of arrow y;

Figure 6 is a plan view of a secondary portion of the non-scissor action 4-way clamp;

Figure 6a is an end view of the secondary portion, variants (i) and (ii), of the non- scissor action 4-way clamp shown in Figure 6 in the direction of arrow a; Figure 6b is an elevation view of the secondary portion, variants (i) and (ii), of the non-scissor action 4-way clamp shown in Figure 6 in the direction of arrow b;

Figure 6c is an elevation view of the secondary portion, variants (i) and (ii), of the non-scissor action 4-way clamp shown in Figure 6 in the direction of arrow y;

Figure 7 is an elevation view of the non-scissor action 4-way clamp shown in

Figure 3, in the direction of arrow y, in assembled form with variants (i) and (ii) of the secondary portion shown;

Figure 8 is an elevation view of the non-scissor action 4-way clamp shown in

Figure 3, in the direction of arrow y, in separated form with variants (i) and (ii) of the secondary portion shown;

Figure 9 is a series of plan views of example variants of the non-scissor action 4- way clamp, where different methods of attaching the primary and secondary portions together are shown, 9a has a hinged alpha/beta portion combination; 9b/ba has complementary shaped alpha and beta portions that slide together to engage, 9c shows complementary alpha and beta portions that positively engage when pushed together;

Figure 10 is a series of views of steps A, B and C of one method of using the non- scissor action 4-way clamp;

Figure 1 1 is a series of views of steps D and E of one method of using the non- scissor action 4-way clamp.

Figure 12 is a plan view of a further embodiment of the invention;

Figure 13 is a detail of Fig. 12; and

Figure 14 is a plan view of a non-scissor 4-way clamp which has a base that allows the distance between the arms to be adjusted.

Definitions:

Clamp: The term clamp is used to describe a device that is used to hold together two or more pieces of material, some call these devices cramps. In general the clamps referred to include a frame and one or more screws with jaws that pass through a portion of the frame, the frame may also include a fixed jaw. Examples include a clamp that has a bow like frame, a clamp that has a‘C’ or‘G’ like frame and frames that allow the spacing between the arms to be adjusted. Hole: a hollow space bounded by a wall in something solid, with an opening on one or both sides. The cross-sectional shape of the opening or wall surrounding the hole can be round, elliptical, semi-circular, square, rectangular, hexagonal, octagonal or any other polygonal shape (regular or irregular) and any combination thereof. The cross-sectional shape may change passing through the hole along the longitudinal axis.

Best Mode for Carrying Out the Invention

Referring to Figure 3 a first variant of a Non-Scissor Action (NSA) 4-way clamp (20) including a primary portion (21 ) and a secondary portion (22) is shown in an assembled form. The same NSA 4-way clamp (20) in separated form is shown in Figure 4.

Referring to Figure 3, Figure 4, Figure 5, 5a, 5b and 5c, where Figure 5a is the primary portion (21 ) shown in Figure 5 viewed in the direction of arrow a, Figure 5b is the primary portion (21 ) shown in Figure 5 viewed in the direction of arrow b, and Figure 5c is the primary portion (21 ) shown in Figure 5 viewed in the direction of arrow y; and Figure 3 or 4 where necessary, the primary portion (21 ) is shown. The primary portion (21 ) is a 3-way clamp including a primary frame (23), two opposed movable primary jaws (24), each attached to a different associated primary screw (25), and one movable secondary jaw (26), attached to an associated primary secondary screw (27). The longitudinal axis of the primary screws (25) are parallel, in the configuration shown they are also coincident. In some configurations one of the primary jaws (24) may be fixed to the primary frame (23), in this case there is no primary screw (25) associated with that primary jaw (24).

The primary frame (23) includes a primary base (28) and two primary arms (29,30). One primary arm (29,30) is attached to each terminal end of the primary base (28) and each primary arm (29,30) extends away from said primary base (28) in the same direction. One primary screw (25) passes through a primary threaded portion (35,36) of each primary arm (29,30) located close to, or immediately adjacent, the terminal end of that primary arm (29,30).

All of the screws 25, 27 are externally threaded; the corresponding threaded portions 35-37 are internally screw-threaded. In the variant shown the primary base (28) and primary arms (29,30) are shown as a single piece, other configurations may rigidly (releasably or permanently) attach one or both primary arms (29,30) close to or at a terminal end of the primary base (28).

The primary frame (23) is shown as‘C’ shaped with the primary secondary screw (27) passing through the mid-point of the primary base (28) and extending in the same direction as the primary arms (29,30). The secondary jaw (26) is at the end of the secondary screw (27) within the interior of the‘C’. The externally-threaded secondary screw (27) passes through a complementary internally threaded portion (37) of the primary frame (23).

The primary frame (23) includes an alpha portion (41 ,42) which is coterminous with, and extending from, the terminal end of each primary arm (29,30). In this embodiment each alpha portion includes an alpha hole (43,44), and the longitudinal axis of each alpha hole (43,44) passes through the plane on which the primary frame (23) and/or primary screws (25,27) lie. The alpha holes (43,44) are shown as being rectangular, but they can be any suitable cross-sectional shape, and that shape may change passing along the length of that alpha hole (43,44). As indicated earlier a hole can refer to an open hole (i.e. terminates at an opening at either end), or a blind hole, (i.e. only one open end).

Referring to Figure 6, 6a, 6b and 6c, where Figure 6a is the secondary portion (22) shown in Figure 6 viewed in the direction of arrow a, Figure 6b is the secondary portion (22) shown in Figure 6 viewed in the direction of arrow b, and Figure 6c is the secondary portion (22) shown in Figure 6 viewed in the direction of arrow y; and Figure 3 or 4 where necessary, the secondary portion (22) is shown.

The secondary portion (22) includes a secondary frame (50) and a secondary jaw (51 ) attached to a externally screw-threaded secondary screw (52), where the secondary frame (50) (when viewed in plan view) is‘C’ shaped.

Said secondary frame (50) includes a secondary base (53) and two secondary arms (54,55). One secondary arm (54,55) is attached to each terminal end of the secondary base (53) and each secondary arm (54,55) extends away from said secondary base (53) in the same direction. In the variant shown the secondary base (53) and secondary arms (54,55) are shown as a single piece, other configurations may rigidly (releasably or permanently) attach one or both secondary arms (54,55) close to or at a terminal end of the secondary base (53).

The secondary screw (52) passes through the secondary base (53) and extends in the same direction as the secondary arms (54,55). The secondary jaw (51 ) is at the end of the secondary screw (52) within the interior of the‘C’. The secondary screw (52) passes through a complementary secondary internally threaded portion (56) of the secondary base (53). The portion 56 is at the mid-point of the secondary base 53.

Each secondary arm (54,55) includes a beta portion (61 ,62) which is located at the exposed terminal end of that secondary arm (54,55). In this embodiment each beta portion (61 ,62) is a piece of material attached to a first face (63) of the secondary frame (50), where the first face (63) is an exposed face of the secondary frame (50). Two variants of the secondary portion (22) are shown in Figure 6, 6a, 6b and 6c, variant (i) and variant (ii). The difference between the two variants is that in variant (i) the beta portion (61 ,62) extends below the plane of the secondary frame (50) and in variant (ii) the end of each secondary arm (54,55) is dog-legged so that the beta portion (61 ,62) terminates close to or at the plane of the secondary frame (50). In use the dog-legged version (version marked (ii)) is configured to allow the force applied between the secondary jaws (26,51 ) to be in the same plane as the force applied between the primary jaws (24).

Referring to Figures 7 and 8 the side view in the direction of arrow y in Figures 3 and 4 is shown for the (i) and (ii) variants. Each beta portion (61 ,62) of the secondary portion (22) engages as a sliding fit with the complementary alpha hole (43,44) in the associated alpha portion (41 ,42) of the primary portion (21 ). The first alpha hole (43) in the first alpha portion (41 ) engages with the first beta portion (61 ) and the second alpha hole (44) in the second alpha portion (42) engages with the second beta portion (62). In the embodiment shown the alpha holes (43,44) and beta portions (61 ,62) have complementary cross sections.

The method of attaching the primary portion (21 ) to the secondary portion (22) can vary from that described in the first embodiment described. The connection between the primary portion (21 ) and secondary portion (22) may consist of a permanent connection or a releasable connection, e.g. hinged sections to engage then disengage, sliding complementary alpha and beta portions (41 ,42,61 ,62), etc.

Referring to Figure 9a a second embodiment of the NSA 4-way clamp (20) is shown, in this variant the first alpha portion (41 ) and first beta portion (61 ) form a hinge (pivot) joint (70) that allows the secondary portion (22) to swing in relation to the primary portion (21 ). The second beta portion (62) is adapted to engage with the second alpha portion (42) to form a releasable attachment, this can be accomplished by incorporating a hinged latch, a spring loaded pin or catch device, a sliding pin or latching device or anything of a similar form. The arrow and dashed representation of the secondary portion (22) show how it moves in relation to the primary section (21 ).

Referring to Figure 9b, and the side view (Figure 9b(a)) in the direction of arrow y a third embodiment of the NSA 4-way clamp (20) is shown. In this embodiment the alpha holes (43,44) are profiled channels adapted to accept a complementary beta portion (61 ,62) where to attach the primary portion (21 ) to the secondary portion (22) a T-shaped beta portion (61 ,62) is slid into the complementary T-shaped alpha hole (43,44) in the matching alpha portion (41 ,42). In this embodiment the longitudinal axis of the channel is essentially parallel to the plane of the NSA 4-way clamp (20). The dashed representation of the secondary portion (22) shows the NSA 4-way clamp (20) in the engaged position.

Referring to Figure 9c the alpha and beta portions (41 ,42,61 ,62) are engaged by pushing the primary and secondary portions (21 ,22) together (in the direction of arrow X). The alpha and beta portions (41 ,42,61 ,62) releasably engage, this engagement can be accomplished by hinged sections that are swung out of the way then engaged, spring loaded pins or catches that engage with complementary features in the other portion, manually engaged/disengaged pins or catches, and combinations of these. The dashed representation of the secondary portion (22) shows it in an intermediate position.

The present invention includes a method of using the NSA 4-way clamp (20) and referring to Figure 10 and Figure 1 1 , steps A to E, with Aa to Ea being views of steps A to E in the direction of arrow a and Cb and Db being views of steps C and D in the direction of arrow b. In step A the primary portion (20) of the NSA 4-way clamp (20) is attached to the column or beam (80) using the primary jaws (24), the clamping force being adjusted by using the primary screws (25). The first piece of material (81 ) is then put into place on the beam or column (80) and the secondary jaw (26) engaged with the surface (82) of the first piece of material (81 ) the force applied by the secondary screw (27) to the secondary jaw (26) being sufficient to maintain the position and orientation of the first piece of material (81 ) relative to the beam or column (80), but allow manual adjustment of that position and orientation. Once the first piece of material (81 ) is in the required position and orientation the secondary screw (27) is used to adjust the force applied by the secondary jaw (26) so as to clamp the piece of material (81 ) in place for further operations. The force applied will depend on the material, ambient conditions and the further work to be carried out, in general (most cases) it will not damage the exposed surface of the first piece of material (81 ).

In step B the hole through the piece of material is drilled, in many cases this will involve passing the drill through pre-drilled holes in the beam or column (80). As the first piece of material (80) is held in place the hole (85) in the first piece of material (81 ) can be drilled completely from the beam or column (80) side, or to minimise surface damage as the drill breaks through from both sides. This ensures that the hole (85) is drilled in the right place with minimum measurement,

In step C the secondary portion (22) is engaged with the primary portion (21 ), or if one of the alpha/beta portion (41 ,42,61 ,62) connections is a hinge joint swung into line to allow the second alpha/beta portion (42,62) connection to be made.

In step D the second piece of material (86) is put into place and the secondary screw (51 ) used to bring the secondary jaw (52) into contact with the second piece of material (86). The force applied to the second piece of material (86) at this stage is sufficient to hold the second piece of material (86) in place, but still allow the position and orientation of the second piece of material (86) to be adjusted to that required. Once the second piece of material (86) is in the required position and orientation the secondary screw (51 ) is used to apply the required clamping force to keep it there.

The hole (87) in the second piece of material (86) is then drilled using the holes in the first piece of material (81 ) and column or beam (80) as a guide. The fixing device (89), in this case a nut and bolt is shown, but it could be any suitable device for holding two pieces of material (81 ,86) to a beam or column (80), for example, nut and bolt, rivet, threaded rod and nuts, etc.

Step E is the removal of the NSA 4-way clamp (20) leaving the pieces of material connected to the column or beam (80).

Referring to Figures 12 and 13, a further embodiment of the invention is shown. In this embodiment, a non-scissors action 4-way clamp 100 includes a primary portion 101 which is removably and pivotally secured to a secondary portion 102 by a pair of opposed pivot joints 103, 104; the pivot joints are shown in greater detail in Figure 13.

The primary portion 101 is a C-shaped frame with a base portion 105 and two opposed arm portions 106, 107. The base portion and the arm portions may be formed separately and secured together by any suitable means, but preferably are formed as a one piece casting. The arm portions 106, 107 are substantially parallel to each other.

Each of the arm portions 106, 107 carries an externally threaded primary screw 108, 109 respectively with a handle, 1 10, 1 1 1 , at one end and a primary jaw 1 12, 1 13, at the other end. Each jaw may be a swivel foot of known type, or (as shown) one of the jaws may be a swivel foot 1 12 and the other jaw may be a larger diameter fixed foot 1 13. Each of these screws 108, 109 is mounted in an internally screw threaded hole 108A, 109A, adjacent the free end of the corresponding arm portion 106, 107. The holes 108A, 109A, are located opposite each other, and lie on a common longitudinal axis A - A.

The base portion 105 carries an externally threaded secondary screw 1 14 with a handle 1 15 and a secondary jaw 1 16 which is a swivel foot of known type. The screw 1 14 is mounted in an internally screw threaded hole 1 14A, which extends through the midpoint of the base portion 105.

The secondary portion 102 also is a C-shaped frame, with a base portion 1 18 and two opposed arm portions 1 19, 120. As with the primary portion, the base portion and the arm portions may be formed separately and secured together by any suitable means, but preferably are formed as a one piece casting. The arm portions 1 19, 120 are substantially parallel to each other. The pivot joints 103, 104, between the free ends of the arms of the primary and secondary portions 101 , 102, as shown in Figure 12 as close to the positions of the screws 108, 109. However, the respective lengths of the adjacent primary and secondary arms, 106, 1 19/107, 120, can be varied for different applications, to place the pivot joints further away from the screws 108, 109.

The secondary portion 102 carries an externally threaded secondary screw 121 with a handle 122 and a secondary jaw 123 which is a swivel foot of known type. The screw 121 is mounted in an internally screw threaded hole 121 A, which extends through the midpoint of the base portion 1 18. The screw threaded holes 1 14A and 121 A lie opposite each other when the primary and secondary portions are connected as shown in Figure 12, and lie on a common longitudinal axis B - B.

The primary and secondary portions 101 , 102 are pivoted together by the pivot joints 103, 104. Each pivot joint consists of an internally screw threaded socket 125, 126, which is formed through a protrusion 125A, 126A, at the free end of the primary arm portions 106, 107. Each protrusion has a height H equal to approximately ½ the width W of the adjacent free end of the primary arm portion; one of the protrusions is positioned on the outer edge of the corresponding arm, the other on the inner edge, as shown in Figure 12. Each of the sockets 125, 126, receives a hardened steel pin 127 (shown in Figure 13 only), which is screwed into the socket. The length of the pin 127 is such that the pin can be screwed into the socket with more than half of the length of the pin protruding from the socket.

The free end of each of the secondary arms 1 19, 120 also is formed with a protrusion 128A, 129A, the same size and shape as the protrusions 125A, 126A; as with the primary arms, one of the protrusions 128A is formed on the inner side of the arm, and the other protrusion 129A is formed on the outer side of the arm.

The primary and secondary portions are connected together by screwing the pins 127 into the sockets 125, 126 as described above and then sliding the secondary portion in the direction of arrow X, so that the protruding ends of the pins 127 enter the holes 128, 129 in the protrusions on the secondary arms, thus connecting the primary and secondary portions pivotally together. The portions can be disconnected by sliding the secondary portion in the opposite direction to arrow X. As with the previously described embodiments, the jaws of each pairs of jaws 1 12/1 13 and 1 16/123 extend towards each other in the centre of the clamp; the spacing between the jaws can be adjusted simply by rotating the corresponding screw, using its handle. The clamp may be used in the same manner as described with reference to Figures 10 and 1 1.

Referring to Figure 14 another embodiment of the NSA 4-way clamp (20) is shown, in this variant each arm (29,30,54,55) includes a collar (100) that allows it to slide along the length of the associated base (28,53) and then locked in position. This allows the distance between the arms (29,30,54,55) adjusted. Methods and devices for adjusting the distance between the arms of clamps are well known and any of these methods can be used. Some devices may incorporate features that allow the length of the base (7,97) or the arms (29,30,54,55) to be adjusted, this could be by multiple (2 or more) telescoping sections which can be locked into an extended position (pins, spring loaded clamps, toggle clamps, spring loaded balls, indents or holes in one or both components, etc.) then unlocked to move back into a non-extended position, shafts or beams with holes along the length with manually engageable pins or spring loaded balls or pins used to maintain the required position, etc. All of the embodiments of the invention described above may be made of any strong, impact-resistant material e.g. iron, steel, plastics. Typically, the primary and secondary portions are made of cast iron and the screws and jaws of mild steel. In the Fig. 12 and 13 embodiment, the pins 127 also are made of steel.