Stop-end clamp

Abstract

Clamp 20 for a stop-end of a wall formwork shutter, for clamping a retaining bar 19 for the stop-end to a waling beam 5 of the formwork shutter, the clamp comprising a first part 22 arranged to hook o

Description

The present invention relates to a clamp and particularly to a clamp suitable for use in fixing a stop-end to a wall formwork. When creating concrete structures, a wall formwork is commonly used which will typically comprise at least two shutter members to define either side of a wall and an end shutter member, or stop-end, to form a construction joint in the concrete wall to make a practical size of concrete pour. The wall formwork will typically comprise a panel, such as plywood, to retain the poured concrete, which panel is braced by a number of horizontally extending waling beams, normally extruded from aluminium. These are in turn retained in place by opposed pairs of vertical beams which are tied together and prevent the wall formwork spreading apart under the weight of the poured concrete. To make a pour of a practical size, construction joints are incorporated into the concrete wall such that a wall is effectively poured in vertical sections. This requires an end panel to be placed across the end of the wall formwork and this end panel may again be plywood sheet, or similar, and will typically have two or more vertically extending beams, supporting the plywood. These vertically extending beams are in turn retained in place against the pressure exerted by the wet poured concrete by multiple cross members, each retained in place by a pair of retaining bars which extend through the cross members and which are clamped in place to appropriate waling beams by clamps. Waling beams are typically in the form of a H-beam with a central box section, with one side of the “H” providing a top and bottom rail extending along the length of the waling beam. Clamps take different forms, but a typical clamp may be a generally “C” shaped clamp and this may be slid on to the two rails from one end of the beam. Once at a desired position, this may then be clamped in place on the beam by a bolt extending through the clamp. Such a clamp will typically have an aperture for receiving a retaining bar attached at an opposite end to the previously mentioned cross member and thus the clamp, or several such clamps, may be used to retain the stop-end in place on the wall formwork. One problem with known clamps is that they have to be fed onto the waling beam from the end of the waling beam, before sliding along the waling beam to the desired position on the waling beam, which may be many tens of centimeters or over a metre from the end of the waling beam. This can sometimes be difficult where the end of the aluminium waling beam has been damaged or the surface of the waling beam has been damaged or contaminated by set concrete, making it difficult to slide a clamp along the rails of the beam. This is particularly a problem because a poured wall may be significantly high, requiring typically four or more cross members each having associated with it two clamps with it being desired to mount cross members at specific locations and thus requiring the clamps to be attached to specific ones of the waling beams. The clamps may also need to be installed by a person who is climbing the formwork. It is an object of the present invention to provide a new improved clamp for a stop-end of a wall formwork shutter. According to the first aspect of the present invention there is provided a clamp for a stop-end of a wall formwork shutter, for clamping a retaining bar for the stop-end to a waling beam of the formwork shutter, the clamp comprising a first part arranged to hook over a top rail of a waling beam and a second part, separate to the first part, arranged to hook under a bottom rail of the waling beam, the two parts being arranged to be joined together such that the first and second parts remain in their hooked positions over the respective ones of the top and bottom rails of the waling beam. An advantage of the present invention is that the clamp may be assembled on to a waling beam from a front face of the shutter at any point along the waling beam, by hooking the first part over the top rail and the second part under the bottom rail prior to the two parts being joined together. This avoids the need to slide the clamp over the end of the aluminium waling beam, which end part is most prone to damage, particularly as aluminium is a weak metal. The invention also avoids the need to slide the clamp along the waling beam, which may difficult to do if the surface of the waling beam is damaged or contaminated by set concrete. Preferably, each of the first and second parts of the clamp has an aperture passing therethrough for receiving a retaining bar to be clamped by the clamp to the waling beam, the retaining bar passing through each of the first and second parts of the clamp acting to join the first and second parts of the clamp together. The advantage of this arrangement is that no additional component is required to lock the two parts of the clamp together, but instead the action of inserting the retaining bar through the clamp, or the two parts of the clamp, will itself join the two parts of the clamp together so that they will then be retained on the waling beam. Preferably, the first and second parts of the clamp are both arranged to freely pivot on the retaining bar by which they are joined together, enabling the two parts of the clamp to be correctly aligned relative to each other on the waling beam. Advantageously, each of the first and second parts of the clamp is in the form of a hook, each having a distal portion having a face arranged to engage behind a respective top or bottom rail of a waling beam and each having an intermediate portion arranged to lie opposed to the distal portion in front of a front face of a respective top or bottom rail of the waling beam. More preferably the clamping system comprises two bolts with each bolt passing through a respective threaded aperture in the intermediate portion of a respective first or second part of the clamp such that, in use, tightening of each bolt will clamp a face of that distal portion opposed to the bolt to the waling beam. In this manner, each part of the clamp can be securely clamped to a respective rail of the waling beam clamping the clamp securely to the waling beam. Preferably, the plane of the hook of each of the first and second parts of the clamp is perpendicular to the axis of the respective aperture for receiving the retaining bar. In this manner, when any cross member for the stop end is secured to the retaining bar and tightened in place on the retaining bar, forces exerting by the retaining bar will be in the direction of the longitudinal axis of the waling beam and will thus not act to displace the waling beam vertically. Advantageously, each of the first and second part of the clamp has a proximal portion in which the aperture for receiving the retaining bar is formed, the proximal portions of the first and second parts of the clamp being arranged to abut together. In this manner, retaining on the retaining beam the part of the clamp which is distal most from the stop-end will act to retain both parts of the clamp by the distal most part abutting the proximal part. Preferably, when the first and second parts of the clamp are abutted together on a retaining bar, the hooks of the first and second parts of the clamp lie on a common plane. In this manner, the hooks will engage with the waling beam one above the other so that forces applied by the retaining bar on the clamp will act equally on the hook of each portion of the clamp. Preferably, the abutting surfaces of the proximal portions of each of the first and second parts of the clamp are chamfered such that, when on a retaining bar, pressing the proximal portions of the first and second parts of the clamp together acts to cause the first part of the clamp to rotate relative to the second part of the clamp until a hook of the first part is facing the hook of the second part and the faces of the distal portions of each part of the clamp lie on a common plane. Thus squeezing the two portions together may ensure the two portions are correctly aligned such that the faces of the distal portions of each part of the clamp lie on a first plane and that the hooks of the first and second parts of the clamp lie on a second plane perpendicular to the first plane. A particular advantage of the present invention is that the first and second portions of the clamp may be identical and interchangeable such that a user, who may be climbing wall formwork in order to install the clamps, only needs to have available one type of clamp portion, which can be used as both the first and second portions of a clamp and these are preferably formed from a cast metal. According to a second aspect of the present invention there is provided a clamping system for stop-end of a wall formwork shutter, the system comprising a threaded retaining bar for retaining a stop-end in place on a formwork shutter, a clamp as described above and a nut for threadedly engaging with the threaded retaining bar so that, in use, with the clamp clamped to a waling beam and with the retaining bar acting on the stop-end, the nut may be positioned on the retaining bar, to be adjacent the clamp, to set or adjust the position of the retaining bar. The presence of the nut enables the clamp to be approximately set in position and then, if desired, the nut may be tightened to retain the retaining bar in the correct position or to tension the retaining bar to assist in sealing the stop-end against the wall formwork. According to a third aspect of the present invention there is provided a method of retaining a stop-end in place on a wall formwork shutter, the method comprising clamping the retaining bars to waling beams of a wall formwork shutter using a clamp as described above. According to a fourth aspect of the present invention there is provided a method of retaining a stop-end in place on a wall formwork shutter, the method comprising, hooking a first part of a clamp of the clamping system described above over an upper rail of a waling beam of the wall formwork shutter, hooking a second part of the clamp under a bottom rail of the waling beam, aligning the apertures for receiving the threaded retaining bar in the first and second parts of the clamp, passing the threaded retaining bar of the clamping system described above through the apertures, tightening a bolt in each of the first and second portions of the clamp to clamp the clamp to the waling bar and positioning the nut of the clamping system described above on the threaded retaining bar against the clamp, to set or adjust the position of the retaining bar and to retain the stop-end against the wall formwork. The advantages of the present invention have been described above with regards to the securing or retaining a stop-end on a wall formwork shutter. However, it will be appreciated that similar advantages to those described above will apply when the stop end is removed from the wall formwork shutter, most notably that each clamp, of which there may be many, may be removed by a person, possibly suspended from or climbing the formwork shutter, from the face of the formwork shutter without the requirement to slide the clamp to the end of the waling beam. One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying figures, of which: Figure 1 is a perspective view of a wall formwork shutter having a stop-end retained in place by clamps in accordance with the present invention; Figure 2 is an enlarged view of the section A of Figure 1; Figure 3 is an enlarged view of the section B of Figure 2; Figure 4 is a top view of the wall formwork shutter of Figure 1; Figure 5 is a cross section along the line V-V of Figure 4; Figure 6 is an enlarged view of the section C of Figure 5; Figure 7 is an enlarged view of the section F of Figure 1, showing two parts of the clamp being located on the top and bottom rails of a waling beam prior to a retaining bar being inserted through them; Figure 8 is an end view of the two parts of the clamp shown in Figure 7; and Figures 9A to 9C are detailed views of a part of the clamp of Figure 7, with the bolt removed. Referring to Figure 1, a wall formwork shutter, indicated generally as 1, comprises two planar shutter members 2 and 3, which may be formed of plywood or other sheet material, which defines the sides of a cavity 4 into which concrete is to be poured to form a vertical wall. The shutter members 1 and 2 are braced by waling beams 5 affixed to the shutter members 2 and 3. The waling beams 5 are themselves in turn braced by opposed pairs of upright beams of which only two upright beams 6 and 7 are shown in Figure 1. The upright beams 6 and 7 are secured together by ties, not shown, and thus retain the shutter members 2 and 3 in place against the forces exerted by the pour fluid concrete prior to the concrete setting. In order to either terminate the wall to be formed, or to form a construction joint in order to limit the size of the pour, a stop-end, indicated generally as 8, is placed across the end of the shutter members 2 and 3. The stop-end comprises a stop-end shutter member 9, which again may be formed from sheet plywood or similar sheet material, and which is braced by two vertical beams 10 and 11, which have the same extruded profile as the waling beams 5 and all of which are extruded from aluminium. The vertical beams 10 and 11 are retained in place by four cross members 12 to 15, which are themselves retained in place by pairs of respective plates 16 and nuts 17, securing each of the cross members 12 to 15 to a respective pair of threaded retaining bars 18 and 19. Each of the threaded retaining bars 18 and 19 is clamped to a respective waling beam 5 by a respective clamp 20. Referring now to Figure 2, this shows to an enlarged scale the section A of Figure 1. Here it can be more clearly seen how a clamp 20 attaches to a waling beam 5 to retain the cross member 13 in place, with a nut 21 acting against the clamp 20 to place the retaining bar under tension and thus retain the cross member 13 against the vertical beams 10 and 11. This retains the vertical beams 10 and 11 against the stop-end shutter member 9 and thus retains the stop-end against the end of the wall formwork shutter 1. Referring now to Figure 3, this shows to an enlarged scale the section B of Figure 2. Here the clamp 20 can be seen to comprise two parts, a first part 22 and a second part 23. The parts 22 and 23 are identical and the first part 22 is shown separately in Figures 9Ato 9C. Each part 22 and 23, as seen in Figures 9Ato 9C, has a threaded aperture 26 for receiving either bolt 27 or 28 of Figure 3. Each of the first part and second part, of which only the first part 22 is shown in Figures 9A to 9C, has a distal portion 30, a proximal portion 31 and an intermediate portion 32. The distal portion 30 has an end face 33 facing the intermediate portion 32 and the threaded aperture 26. The proximal portion 31 has a non-threaded aperture 34 extending through it and a chamfered abutment surface 35. Referring now to Figure 4, this is a top view of the wall formwork shutter 1 of Figure 1, with Figure 5 a section on the line V-V of Figure 4. This shows a clamp 20 mounted on a waling beam 5 and clamped in place by a pair of bolts 27 and 28, with the section C of Figure 5 shown to an enlarged scale in Figure 6. Referring now to Figure 6, a cross section through a clamp 20 when attached to waling beam 5, this shows the first part of the clamp 22 hooked over the top rail of the waling beam 5 and the second part 23 of the clamp 22 hooked under the bottom rail 25 of the waling beam 5. The bolts 27 and 28 are shown tightened in their respective threaded apertures 26 extending through the first and second parts 22 and 23 of the clamp 20, in order to clamp the respective first and second parts 22 and 23 of the clamp 20 to the waling beam 5. This thus secures the clamp 20 to the waling beam 5 such that tensional forces can then be applied to the threaded retaining bar 19 extending through the clamp by the nut 21, not seen in Figure 6. It will be appreciated from Figure 6 that, with the threaded retaining bar 19 passing through the non-threaded apertures 34 in the first and second parts 22 and 23 of the clamp 20, joining the two parts 22 and 23 together, the clamp 20 could not be positioned on the waling beam 5, or removed from the waling beam 5 without being either slid from, or slid to, the end of the waling beam 5. However, with reference to Figure 7, this shows to an enlarged scale the section F of Figure 1 where a clamp 36, for illustrative purposes only, is shown part assembled on a waling beam 5. Figures 7 and 8 show the part assembled clamp 36, with bolts 27 and 28 inserted into, but not through, the respective first and second parts 22 and 23 of the clamp 36. At this stage the threaded retaining bar, 18 or 19, has also not been inserted through the none threaded apertures 34 in the two parts 22 and 23 of the clamp 36. This permits the separate first part 22 of the clamp 36 to first be hooked on to the top rail 24 of the waling beam 5 and then the second part 23 of the clamp 36 to be hooked under the bottom rail 25 of the waling beam 5. The first and second parts 22 and 23 of the clamp 36 can then be positioned to align the nonthreaded apertures 34 of each part, with the chamfered abutment surfaces 35 engaging with each other to act to align the first and second parts 22 and 23 of the clamp 36, such that their end faces 33 lie in a common plane as shown in Figure 6 parallel to the back faces of the top rail 24 and bottom rail 25 of the waling beam 5. These are then correctly positioned and the bolts 27 and 28 may be tightened prior to the threaded retaining bar 18 or 19 being inserted. Alternatively the threaded retaining bar 18 or 19 may be inserted first through the two parts 22 and 23 of the clamp 36 and the two parts 22 and 23 then pushed together such that their abutment surfaces then act to align the two parts correctly, prior to bolts 27 and 28 being tightened. It will be appreciated that not only may the clamp be conveniently attached midway along a waling beam as previously described, but when it is desired to remove the clamp, the clamp may also be removed from midway along a waling beam by the reverse process, without the need to slide the clamp onto or of the end of the waling beam. One embodiment of the present invention has been described above, by way of example only, and it will be appreciated that alternative arrangements or modifications may be made which may fall within the scope of the following claims.

Claims

1. A clamp for a stop-end of a wall formwork shutter, for clamping a retaining bar for the stop-end to a waling beam of the formwork shutter, the clamp comprising a first part arranged to hook over a top rail of a waling beam and a second part, separate to the first part, arranged to hook under a bottom rail of the waling beam, the two parts being arranged to be joined together such that the first and second parts remain in their hooked positions over the respective ones of the top and bottom rails of the waling beam.

2. A clamp as claimed in Claim 1, wherein each of the first and second parts has an aperture passing therethrough for receiving a retaining bar to be clamped by the clamp to the waling beam, the retaining bar passing through each of the first and second parts of the clamp acting to join the first and second parts of the clamp together.

3. A clamp as claimed in Claim 2, wherein the first and second parts of the clamp are each arranged to freely pivot on the retaining bar by which they are joined together.

4. A clamp as claimed in Claim 2 or 3, wherein each of the first and second parts of the clamp is in the form of a hook, each having a distal portion having a face arranged to engage behind a respective top or bottom rail of a waling beam and each having an intermediate portion arranged to lie opposed to the distal portion in front of a front face of a respective top or bottom rail of the waling beam.

5. A clamp as claimed in Claim 4, further comprising two bolts, each passing through a respective threaded aperture in one of the intermediate or distal portion of a respective first or second part of the clamp such that, in use, tightening of each bolt will clamp a face of the other of the distal portion or intermediate portion opposed to the bolt to the waling beam.

6. A clamp as claimed in Claim 4 or 5, wherein the plane of the hook of each of the first and second parts of the clamp is perpendicular to the axis of the respective aperture for receiving the retaining bar.

7. A clamp as claimed in Claim 6, wherein each of the first and second parts of the clamp has a proximal portion in which the aperture for receiving the retaining bar is formed, the proximal portions of the first and second parts of the clamp being arranged to abut together.

8. A clamp as claimed in Claim 7, wherein, when the first and second parts of the clamp are abutted together on a retaining bar, the hooks of the first and second parts of the clamp lie on a common plane.

9. A clamp as claimed in Claim 8, wherein abutting surfaces of the proximal portions of each of the first and second parts of the clamp are chamfered such that, when on a retaining bar, pressing the proximal portions of the first and second parts of the clamp together acts to cause the first part of the clamp to rotate relative to the second part of the clamp until a hook of the first part is facing the hook of the second part and the faces of the distal portions of each part of the clamp lie on a common plane.

10. A clamp as claimed in Claim 9, wherein when the first and second parts of the clamp are pressed together, such that the faces of the distal portions of each part of the clamp lie on a first plane, the hooks of the first and second parts of the clamp lie on a second plane perpendicular to the first plane.

11. A clamp as claimed in any one of Claims 2 to 10, wherein the first and second parts of the clamp are identical and interchangeable.

12. A clamp as claimed in any of Claims 2 to 11, wherein the first and second parts of the clamp are cast metal.

13. A clamping system for a stop-end of a wall formwork shutter, the system comprising a threaded retaining bar for retaining a stop-end in place on a formwork shutter, a clamp as claimed in any one of Claims 2 to 11 and a nut for threadedly engaging with the threaded retaining bar so that, in use, with the clamp clamped to a waling beam and with the retaining bar acting on the stop-end, the nut may be positioned on the retaining bar, to be adjacent the clamp, to set or adjust the position of the retaining bar.

14. A method of retaining a stop-end in place on a wall formwork shutter, the method comprising clamping retaining bars to waling beams of a wall formwork shutter using a clamps as claimed in one of Claims 1 to 12.

15. A method of retaining a stop-end in place on a wall formwork shutter, the method comprising, hooking a first part of a clamp of the clamping system of Claim 13 over an upper rail of a waling beam of the wall formwork shutter, hooking a second part of the clamp under a bottom rail of the waling beam, aligning the apertures for receiving the threaded retaining bar in the first and second parts of the clamp, passing the threaded retaining bar of the clamping system of Claim 13 through the apertures, tightening a bolt in each of the first and second portions of the clamp to clamp the clamp to the waling bar and positioning the nut of the clamping system of Claim 13 on the threaded retaining bar against the clamp, to set or adjust the position of the retaining bar and to retain the stop-end against the wall formwork.AMENDMENTS TO THE CLAIMS HAVE BEEN FILED AS FOLLOWS:-Claims1. A wall formwork shuttering system comprising a wall form work shutter having a waling beam, a stop end for the wall formwork shutter, a retaining bar for5 the stop end and a clamp for clamping the retaining bar for the stop-end to the waling beam, the clamp comprising a first part arranged to hook over a top rail of a waling beam and a second part, separate to the first part, arranged to hook under a bottom rail of the waling beam, the two parts being arranged to be joined together such that the first and second parts remain in their hooked positions over the10 respective ones of the top and bottom rails of the waling beam, wherein each of the first and second parts has an aperture passing therethrough, with the axis of the apertures aligned with a major axis of the waling beam when the first and second parts are hooked over and under respective top and bottom rails of the waling1*0 beam, the apertures being arranged to receive the retaining bar to be clamped by C\| 15 the clamp to the waling beam, the retaining bar being received by the apertures ina direction generally parallel to the major axis of the waling beam and passing through each of the first and second apertures of the clamp acting to join the first and second parts of the clamp together.20 2. A shuttering system as claimed in Claim 1, wherein the first and secondparts of the clamp are each arranged to freely pivot on the retaining bar by which they are joined together.

3. A shuttering system as claimed in Claim 1 or 2, wherein each of the first and 25 second parts of the clamp is in the form of a hook, each having a distal portionhaving a face arranged to engage behind a respective top or bottom rail of a waling beam and each having an intermediate portion arranged to lie opposed to the distal portion in front of a front face of a respective top or bottom rail of the waling beam.30 4. A shuttering system as claimed in Claim 3, further comprising two bolts,each passing through a respective threaded aperture in one of the intermediate or distal portion of a respective first or second part of the clamp such that, in use,tightening of each bolt will clamp a face of the other of the distal portion or intermediate portion opposed to the bolt to the waling beam.

5. A shuttering system as claimed in Claim 3 or 4, wherein the plane of the 5 hook of each of the first and second parts of the clamp is perpendicular to the axis of the respective aperture for receiving the retaining bar.

6. A shuttering system as claimed in Claim 5, wherein each of the first and second parts of the clamp has a proximal portion in which the aperture for receiving 10 the retaining bar is formed, the proximal portions of the first and second parts of the clamp being arranged to abut together.

7. A clamp as claimed in Claim 6, wherein, when the first and second parts of 1*0 the clamp are abutted together on a retaining bar, the hooks of the first and second C\| 15 parts of the clamp lie on a common plane.

8. A shuttering system as claimed in Claim 7, wherein abutting surfaces of the proximal portions of each of the first and second parts of the clamp are chamfered 1 such that, when on a retaining bar, pressing the proximal portions of the first and20 second parts of the clamp together acts to cause the first part of the clamp to rotate relative to the second part of the clamp until a hook of the first part is facing the hook of the second part and the faces of the distal portions of each part of the clamp lie on a common plane.25 9. A shuttering system as claimed in Claim 8, wherein when the first andsecond parts of the clamp are pressed together, such that the faces of the distal portions of each part of the clamp lie on a first plane, the hooks of the first and second parts of the clamp lie on a second plane perpendicular to the first plane.30 10. A shuttering system as claimed in any preceding claim wherein the first andsecond parts of the clamp are identical and interchangeable.10 11 2511. A shuttering system as claimed in any preceding claim, wherein the first and second parts of the clamp are cast metal.

12. A shuttering system as claimed in any preceding claim wherein the retaining 5 bar is threaded and wherein the system further comprises a nut for threadedlyengaging with the threaded retaining bar so that, in use, with the clamp clamped to a waling beam and with the retaining bar acting on the stop-end, the nut may be positioned on the retaining bar, to be adjacent the clamp, to set or adjust the position of the retaining bar.1013. A clamp for a shuttering system in accordance with any preceding claim.

14. A method of retaining a stop-end in place on a shuttering system in accordance with Claim 12, the method comprising, hooking a first part of a clamp 15 of the shuttering system over an upper rail of the waling beam, hooking a secondpart of the clamp under a bottom rail of the waling beam, aligning the apertures for receiving the threaded retaining bar in the first and second parts of the clamp, passing the threaded retaining bar through the apertures, tightening a bolt in each of the first and second portions of the clamp to clamp the clamp to the waling bar20 and positioning the nut on the threaded retaining bar against the clamp, to set or adjust the position of the retaining bar and to retain the stop-end against the wall formwork.

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