GB2577245A

GB2577245A - A tie for a shutter member

Info

Publication number: GB2577245A
Application number: GB1814660.5A
Authority: GB
Inventors: Kiss Paul; Fraser Dunstan Karl; Grist David
Original assignee: Abbey Pynford Holdings Ltd
Current assignee: Abbey Pynford Holdings Ltd
Priority date: 2018-09-10
Filing date: 2018-09-10
Publication date: 2020-03-25
Anticipated expiration: 2038-09-10
Also published as: GB2577245B; GB201814660D0

Abstract

A tie 3 for a shutter member 2 of a shuttering system 1, for supporting concrete 22 during construction of a structure, in which the tie comprises a metal strip having a first end opposite to a second end, with at least the one of the two ends being arranged to pass through a slot in a wall 5, or base portion 4, of the shutter member 2, wherein the tie has a line of weakness towards the at least one end, defining a tab 20, 11, the tie 3 being arranged to be bent along the line of weakness in order that the tab 20, 11 may form a retaining portion of the tie 3, to retain the tie 3 in a slot 10, 9 in a shutter member 2 and anchor a wall 5 of the shutter member 2 to a base 4. A shuttering system is also disclosed.

Description

A Tie for a Shutter Member The present invention relates to a tie for a shutter member of a shuttering system, for supporting concrete or other settable material during construction of a structure, such as a foundation raft or other low level beam.

In the building industry, it is known to erect building or other super structure on a raft or beam which may be supported by piles, or cast directly on a suitably prepared piece of ground. This requires a shutter to be erected in order to retain the poured concrete, or other settable material, hereinafter referred to generally as "concrete", until the concrete is set. Traditionally, this would have been achieved by sheeting retained in place by stakes and more recently by braced steel shuttering.

The present invention aims to provide an improved shuttering system and particularly a tie for such a shuttering system.

According to the present invention there is provided a tie for a shutter member of a shuttering system for supporting concrete or other settable material during construction of a structure, the tie comprising a metal strip having a first end opposite to a second end, with at least the one of the two ends being arranged to pass through a slot in a shutter member of the shuttering system, wherein the tie has a line of weakness towards the at least one end, the line of weakness defining a tab distal of the line of weakness, the tie being arranged to be bent along the line of weakness in order that the tab may form a retaining portion of the tie, to retain the tie in a slot in a shutter member.

The present invention provides a tie which may be assembled with a shutter member on site, by a tab on an end of the tie being arranged to be bent in order to retain the tie in place. The tab is arranged to be bent by having a line of weakness which may enable the tab to be bent either by hand or by the use of simple tools normally available on site, such as a hammer. A significant advantage of this is that it enables the ties and shutter members to be transported to site unassembled and then to be assembled on site, as and when required. This assists in transportation and storage and also avoids the need for assembly to occur in a factory producing either the ties or shutter members. Instead these can simply be stamped and folded ready for shipment, without the need for any expensive and time consuming welding processes.

The metal strip of each tie is preferably shaped to have an abutting portion arranged to abut against a shutter member at an edge of a slot in a shutter member through which the tab of the tie is arranged to pass. The abutting member may be used to ensure the tie is correctly aligned in a shutter member, prior to the tab being bent to retain the tie in the shutter member, or where the tab is already bent prior to insertion in the shutter member enables the tab to be inserted through the shutter member with a first alignment and then, when the abutting portion abuts the edge of the slot, to be realigned and thus position the tab behind that portion of the shutter member through which the tab has been inserted.

The above abutting portion may be formed by an inward step on at least one edge of the metal strip in a width direction, which inward step is approximately in line with the line of weakness defining the tab, the tab being narrower than the width of the metal strip proximal to the step. In this way, the tab may be inserted into a slot in a shutter member until the shoulder of the step engages with the edge of the slot in the shutter member, which will then ensure the line of weakness is aligned with the edge of the slot in the shutter member, such that the edge of the slot may be used as a fulcrum to assist the bending of the tab.

The metal strip may have a pair of inward steps on opposite edges of the metal strip, which inward steps are both approximately in line with the line of weakness. The provision of two steps on opposite edges ensures that the line of weakness will be correctly aligned with the edge of the slot, assisting bending of the tab as previously mentioned.

In an alternative embodiment, the metal strip may have a slot extending inwardly from one edge, with one side of the slot forming the abutting portion. In this manner, the metal tie may be arranged to be inserted in a longitudinal direction into a slot in the shutter member, before being moved either transversely or at an oblique angle to the slot it has been inserted through, so that the portion of the shutter member with which the tie is to engage, which will normally be in the form of sheet steel, may engage with the slot in the tie, retaining the tie in the desired position. This is particularly advantageous where the slot, at least in part, defines the line of weakness, for engaging the slot will ensure that the line of weakness is also correctly positioned relative to the shutter member.

The line of weakness may be perpendicular to a longitudinal axis of the tie, or it may be at an oblique angle to the longitudinal axis of the tie.

In one embodiment, a tie may have a line of weakness towards each respective end to define two tabs, each of which is distal of the associated line of weakness, the tie being arranged to be bent along the lines of weakness in order that the tabs may form retaining portions at either end of the tie, to retain the tie in respective, substantially opposed, slots in a shutter member. In this way, a tie may engage at each respective end with two parts of a shutter member, such as a base portion and a wall and thus may be arranged to tie the wall to the base to, in use, restrain the wall in a desired position against wet concrete acting against the wall.

The tie may have a first line of weakness at a first end defining a first tab, distal to the first line of weakness, and a second line of weakness at a second end defining a second tab, distal of the second line of weakness, wherein at the first end the metal strip has two opposed inward steps each substantially in line with the first line of weakness, with the first line of weakness extending across the metal strip perpendicular to a longitudinal axis of the metal strip and, at the second end, the metal strip has a slot extending inwardly from one edge with the slot, at least in part, defining the second line of weakness, both the slot and the second line of weakness being at an oblique angle to the longitudinal axis of the metal strip.

In addition, the second end of the tie may be angled so that the tie has a long edge and a short edge, the second line of weakness extending from the end of the short edge to the slot located in the long edge, to define a triangular tab.

A tie with the above described configuration may advantageously be used with some embodiments of a shutter member, as will become apparent from the description of the drawings contained later in this application.

The, or each, line of weakness may comprise one or more perforations through the metal strip, or alternatively may comprise a line where the metal strip is thinner. Each of these arrangements will assist in bending the metal strip, avoiding the need for tools, or requiring only very simple tools, and also ensuring that the metal strip bends at the desired position. This may be important where a shutter member has, for example, a base portion and a wall with the base portion being anchored to the ground, for it will then be important that the tabs are correctly formed and bent in order to correctly position the wall relative to the base portion, to ensure the wall is upright, or at some other desired angle, relative to the base portion.

According to a second aspect of the present invention there is provided a shutter member for a shuttering system for supporting concrete or other settable material during construction of a structure, the shutter member comprising a base portion and a wall extending upwardly from the base portion, the wall having a first side arranged to restrain a mass of concrete or other settable material during formation of the structure, the shutter member having at least one slot formed in one of the wall or the base portion, which slot is arranged to receive and retain in place a tab of a tie as described above.

A shutter member as described above is advantageous, for it may be transported to site prior to the tie being inserted, to extend between the base portion and wall portion, thus permitting a plurality of shutter members to be nested during storage and transportation to site. In addition, with such a shutter member, the tie permits the base portion to be arranged on a substrate on which the concrete is to be poured, with the base portion located in the area the concrete is to be poured. Thus the tie, under tension, may retain the wall in place against the force exerted by the wet concrete, with the base portion and the tie being covered by the concrete, permitting the shutter member to be left in place after the concrete has set.

A significant advantage of this is that, when the concrete, for example forming a concrete raft, has set, the shuttering system 1 does not need to extend beyond the edge of the concrete raft and thus there is no need to remove the shuttering. This offers a significant advantage over shuttering systems where the shuttering system remains exposed after the concrete has been poured and thus subsequently has to be removed. This is because the presence of shuttering which remains exposed after the concrete has been poured, normally prevents further access to the site immediately around the poured concrete raft, until after the raft has set, for disturbance of external shuttering may result in damage to the raft prior to it setting. In addition, the presence of the shuttering may physically prevent access to the area immediately surrounding the raft, even after the concrete has set. This may hold up the next stage of construction.

Furthermore, the shuttering may be required to be removed by the company responsible for the forming of the raft, which may require them to make an additional visit to the site, once the raft has set, in order to remove the shuttering. In contrast, with a shuttering system employing a shutter member in accordance with the present invention, the area immediately adjacent the raft is accessible immediately after the concrete has been poured, with the wall of the shutter member protecting the vulnerable end face and top edges of the raft being formed.

Preferably, the shutter member comprises an opposed pair of slots for respectively receiving tabs at opposed end of the tie, wherein one slot of the pair of slots is in the base portion and the other slot of the pair of slots is in the wall, for the tie may then tie the wall to the base portion.

According to the third aspect of the present invention there is provided a shuttering system for supporting concrete or other settable material during construction of a structure, the shuttering system comprising at least one tie as described above, the shutter member comprising a base portion and a wall extending upwardly from the base portion, the wall having a first side arranged to restrain a mass of concrete, or other settable material, during formation of the structure, the shutter member having at least one slot formed in one of the wall or the base portion, wherein the tab of the tie extends through the slot and, in use, is held in the slot under tension by the tab being bent along an associated line of weakness, so that the tab engages with an opposite face of the wall, or base portion, to the face from which the remainder of the tie protrudes, such that the bent over tab prevents the tie being pulled back through the slot.

More preferably, the shutter member comprises at least one opposed pair of slots for respectively receiving tabs at opposed ends of the tie, wherein one slot of the pair of slots is in the base portion and the other slot of the pair of slots is in the wall and more preferably the base portion is arranged to be anchored to the substrate on which the concrete or other settable material is to be poured.

According to a fourth aspect of the present invention, there is provided a method of supporting concrete or other settable material during construction of a structure. The method employing a shuttering system as described above, and comprising the steps of transporting a plurality of shutter members to a site and transporting a plurality of ties to a site before, on site, assembling the ties and shutter members, either before or after aligning a plurality of shutter members to define the edge of a structure to be formed and securing the shutter members to a substrate on which the structure is to be formed. The method further comprising the step of pouring concrete or other settable material on the substrate and over the base portion of the shutter member, such that the concrete or other settable material is retained by the walls of the shutter members which are retained upright by the ties extending under tension between the walls and the base portions of the shutter members, with the concrete or other settable material enveloping the ties.

One embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, of which: Figure 1 is a perspective view of a shuttering system in accordance with the present invention; Figure 2 is an end elevation of the shuttering system of Figure 1; Figure 3 is a perspective view of a shutter member of the shuttering system Figure 1; Figure 4 is an end elevation of the shutter member of Figure 3; Figure 5 is a plan view of a stamped metal strip to form a tie of the shuttering system of Figure 1; Figure 6 shows the tie of Figure 5, but with a quarter twist in a central portion thereof and with one a tab bent at 90°; Figure 7 is a perspective view of the tie shown in Figure 6; Figure 8 is a further perspective view of the tie of Figure 6, but with two tabs bent to the positions they would adopt when assembled in the shuttering system of Figure 1; Figure 9A is a rear perspective view of the shuttering system shown in Figure 1; Figure 9B is an enlarged section 'A' of Figure 9A; Figure 10 schematically illustrates a side elevation of the shuttering system of Figure 1, when in use restraining a body of poured concrete; and Figure 11 shows how multiple shutter members may be stacked prior to the ties being inserted.

Referring now to Figures 1 and 2, a shuttering system, indicated generally as 1, comprises a shutter member 2 and a plurality of ties 3. The shuttering system of Figure 1 is one length of a larger shuttering system, which will comprise many shutter members 2, arranged end to end, to define the size and shape of a concrete raft, or similar, that is to be subsequently poured.

Referring now to Figures 3 and 4, these show the shutter member 2 of Figures 1 and 2 prior to the ties 3 being installed. The shutter member 2 is stamped and folded from a metal sheet to have the shape and profile shown in Figures 3 and 4. This comprises a base portion 4, the base portion 4 having an edge portion 4a bent upwards, as shown, to stiffen that edge of the base portion in a longitudinal direction of the shutter member 2. At the opposite side (the left-hand side as shown in Figure 4), the metal sheet of the shutter member 2 is bent at 90° to form a wall 5. The wall 5 has an indented channel 6 which acts to stiffen the wall 5 in the longitudinal direction.

Additionally, a top edge 7 of the wall 5 is bent to have the n-shaped profile, shown in Figure 4. This acts to stiffen the top edge of the wall 5 in the longitudinal direction, which is important as this will define the finished edge of the structure formed by the poured concrete, shuttered by the shutter member 2.

The n-shaped profile of the top edge 7 of the wall 5 also permits adjacent shutter members to be joined together, by inserting connecting members (not shown) in the form of appropriate sized box shaped or n-shaped metal sections. This ensures that the top edges of adjacent shuttering members remain correctly aligned when the concrete is poured.

The base portion 4 has a number of apertures 8 formed through it, which are arranged to receive fastenings to anchor the base portion 4 to a substrate 23 on which the settable concrete is to be poured, as described below with reference to Figure 10.

Additionally, the base portion 4 has a first array of slots 9, each orientated in the longitudinal direction of the shutter member 2. The wall 5 has a second array of slots 10, with each of the slots 10 positioned opposite to a respective one of the slots 9, to form respective pairs of slots. The slots 10 are each aligned vertically and are located in the indented channel 6 of the wall 5. Each pair of slots 9 and 10 is arranged to receive a respective tie 3, as shown in Figures 1 and 2.

Referring now to Figure 5, this shows a tie 3 in the process of being formed, where it comprises a stamped piece of metal strip. The metal strip is stamped to the shape shown to provide, at a first end, a first tab 11 defined by a perforation 12. The first tab 11 may be bent relative to the main body of the tie 3 about a first line of weakness defined by the perforation 12.

The edges 16, 17, in the width direction of the tie 3, are formed with opposed steps 13 and 14, which are generally in alignment with the line of weakness defined by the perforation 12 running across the proximal end of the tab 11. Thus, the tab 11 is narrower than the main body of the metal strip forming the tie 3.

At a second end of the tie 3, opposite to the tab 11, the metal strip is formed with a diagonal end 15, such that one edge 16 of the metal strip is shorter than the other edge 17. Two perforations 18 and a slot 19 lie, approximately in alignment, obliquely across the second end of the strip. These define a second line of weakness and define a second tab 20, which may be bent relative to the main body of the tie 3, about the second line of weakness formed by the perforations 18 and the slot 19.

Referring now to Figures 6 and 7, these show the tie after a quarter twist 21 has been made in the central portion of the metal strip of the tie 3. Additionally the first tab 11 has been bent about the line of weakness created by the perforation 12 so that it is at 90° to main body of the tie 3.

The first tab 11 may be bent at 90° to the main body of the tie 3, as shown in Figures 11 and 12 prior to assembly in the shutter member of Figures 3 or 4, or it may be left flat and inserted in a flat state.

Referring now to Figure 8, this shows how the tie 3 will be bent once it is assembled in the shutter member 2, as seen in Figures 1 and 2.

Referring now to both Figures 6 and 7, and also Figure 3, the tie 3 with the first tab either bent upwards, as shown in Figures 6 and 7, or still flat, may be assembled in the shutter member 2 of Figure 3. This may be achieved, for example, by first inserting the tab 11 through one of the slots 9 in the base portion 4 of the shutter member 2, until the steps 13 and 14 of the tie 3 abut the edges of the slot 9 in the shutter member 2. Then the second tab 20 may be inserted in the corresponding slot 10, in the wall 6, until the back edge of the slot 19 in the tie 3 engages with the edge of the slot 10, preventing the tie 3 being inserted further through the slot 10. To achieve this it may be necessary to either flex the back of the wall 6 relative to the base portion 4, or it may be necessary to flex the tie 3. In either case, when either the shutter member 2 resiles back to its natural position, or the tie 3 resiles back to its natural position, the tie 3 will be correctly positioned in the shutter member 2, with the lines of weakness defined by the perforations 12 and 18 aligned with the edges of the respective slots 9 and 10. At this point, the tabs 11 and 20 may be bent to the final positions, as shown in Figures 1, 2 and 8, which may be achieved by bending them by hand or, for example, striking them with a hammer.

With reference to Figure 1, it will be apparent how the tabs 11 prevent the respective ties 3 being pulled out of the base portion 4.

Referring now to Figures 9A and 9B, and particularly the enlarged insert A of Figure 9B, this shows a second tab 20 of a tie 3 bent over flush with the rear face of the indented channel 6 in the wall 5. The tab 20 is thus recessed in the indented channel 6, which is possible due to the tab 20 being triangular in shape. The tab 20, once bent over as shown in Figure 9B, will prevent the tie 3 being pulled out of the slot 10.

With reference to Figure 10, this shows schematically in elevation a section of the shuttering system 1 attached to a substrate 23 and retaining poured concrete 22 until it has set.

In use, a construction worker will secure a shutter member 2 to a substrate 23 on which the concrete 22 is to be poured by means of fastenings 24. This may be before or after, on site, inserting and attaching the ties 3 in the shutter member 2, to create a shuttering system as shown in Figures 1 and 2. Once the shuttering system 1, with the ties 3 in place, is secured to the substrate 23, as shown in Figure 10, the concrete 22 may be poured. The ties 3 then retain the wall 5 in the upright position, as shown in Figure 10, with the poured concrete covering both the base portion 4 and the ties 3, leaving only one side of the wall 5 exposed. Thus the shuttering system 1 may be left in place, with the wall 5 of the shuttering system 1 forming the outer face of the raft. The tabs 20, protruding through the wall 5 are, as seen most clearly from Figure 10, recessed in the indented channel 6 in the wall 5. As well as being potentially more aesthetically pleasing than if they had been proud of the surface of the wall, this also acts to prevent them snagging clothing or other items on site.

Referring now to Figure 11, this shows how a plurality of shutter members 2 may be stacked for storage and transportation prior to the ties 3 being inserted on site.

One embodiment of the present invention has been described above by way of example only and it will thus be appreciated that many alternative arrangements may be possible which fall in the scope of the invention as defined by the following claims.

Claims

Claims 1. A tie for a shutter member of a shuttering system for supporting concrete or other settable material during construction of a structure, the tie comprising a metal strip having a first end opposite to a second end, with at least the one of the two ends being arranged to pass through a slot in a shutter member of the shuttering system, wherein the tie has a line of weakness towards the at least one end, the line of weakness defining a tab distal of the line of weakness, the tie being arranged to be bent along the line of weakness in order that the tab may form a retaining portion of the tie, to retain the tie in a slot in a shutter member.
2. A tie as claimed in Claim 1, wherein the metal strip is shaped to have an abutting portion arranged to abut against a shutter member at an edge of a slot in a shutter member through which the tab of the tie is arranged to pass.
3. A tie as claimed in Claim 2, wherein the abutting portion is formed by an inward step on at least one edge of the metal strip in a width direction, which inward step is approximately in line with the line of weakness defining the tab, the tab being narrower than the width of the metal strip proximal to the step.
4. A tie as claimed in Claim 3, wherein the strip has two opposed inward steps on opposite edges of the metal strip, which inward steps are both approximately in line with the line of weakness.
5. A tie as claimed in Claim 2, wherein the metal strip has a slot extending inwardly from one edge, with one side of the slot forming the abutting portion.
6. A tie as claimed in Claim 5, wherein the slot, at least in part, defines the line of weakness.
7. A tie as claimed in any preceding claim, wherein the line of weakness is perpendicular to a longitudinal axis of the metal strip.
8. A tie as claimed in any one of Claims 1 to 6, wherein the line of weakness is at an oblique angle to a longitudinal axis of the metal strip.
9. A tie as claimed in any preceding claim, having a line of weakness towards each respective end to define two tabs, each of which is distal of the associated line of weakness, the tie being arranged to be bent along the lines of weakness in order that the tabs may form retaining portions at either end of the tie, to retain the tie in respective, substantially opposed, slots in a shutter member.
10. A tie as claimed in Claim 9, having a quarter twist in a central portion between the two tabs, so that one line of weakness lies in a plane substantially perpendicular to a plane in which the other line of weakness lies.
11. A tie as claimed in Claim 10, having a first line of weakness at a first end defining a first tab, distal to the first line of weakness, and a second line of weakness at a second end defining a second tab, distal of the second line of weakness, wherein at the first end the metal strip has two opposed inward steps each substantially in line with the first line of weakness, with the first line of weakness extending across the metal strip perpendicular to a longitudinal axis of the metal strip and, at the second end, the metal strip has a slot extending inwardly from one edge with the slot, at least in part, defining the second line of weakness, both the slot and the second line of weakness being at an oblique angle to the longitudinal axis of the metal strip.
12. A tie as claimed in Claim 11, wherein the second end of the tie is angled so that the tie has a long edge and a short edge, the second line of weakness extending from the end of the short edge to the slot located in the long edge, to define a triangular tab.
13. A tie as claimed in any preceding claim, wherein the, or each, line of weakness comprises a one or more perforations through the metal strip.
14. A tie as claimed in any preceding claim, wherein the, or each, line of weakness comprises a line where the metal strip is thinner.
15. A shutter member for a shuttering system for supporting concrete or other settable material during construction of a structure, the shutter member comprising a base portion and a wall extending upwardly from the base portion, the wall having a first side arranged to restrain a mass of concrete or other settable material during formation of the structure, the shutter member having at least one slot formed in one of the wall or the base portion, which slot is arranged to receive a tab of a tie as claimed in any preceding claim and to retain the tie in place.
16. A shutter member as claimed in Claim 15, comprising an opposed pair of slots for respectively receiving tabs at opposed end of the tie, wherein one slot of the pair of slots is in the base portion and the other slot of the pair of slots is in the wall.
17. A shutter member as claimed in Claim 15 or 16, wherein the slot in the wall is aligned vertically.
18. A plurality of shutter members as claimed in any one of Claims 15 to 17, which are arranged to be nested or partly nested for transportation and storage, prior to at least one tie being attached.
19. A shuttering system for supporting concrete or other settable material during construction of a structure, the shuttering system comprising at least one tie as claimed in any one of Claims 1 to 14, the shutter member comprising a base portion and a wall extending upwardly from the base portion, the wall having a first side arranged to restrain a mass of concrete or other settable material during formation of the structure, the shutter member having at least one slot formed in one of the wall or the base portion, wherein the tab of the tie extends through the slot and, in use, is held in the slot under tension by the tab being bent along an associated line of weakness so that the tab engages with an opposite face of the wall, or base portion, to the face from which the remainder of the tie protrudes, such that the bent over tab prevents the tie being pulled back through the slot.
20. A shuttering system as claimed in Claim 19, wherein the shutter member comprises at least one opposed pair of slots for respectively receiving tabs at opposed end of the tie, wherein one slot of the pair of slots is in the base portion and the other slot of the pair of slots is in the wall.
21. A shuttering system as claimed in Claim 19 or 20, wherein the base portion is arranged to be anchored to a substrate on which the concrete or other settable material is to be poured.
22. A shuttering system as claimed in any one of Claims 19 to 21, wherein a plurality of ties are arranged to be assembled with a plurality of shutter members on site by the tabs of the ties being inserted into respective slots in the shutter members with the tabs being subsequently bent over either by hand or with the aid of simple tools in order to retain the ties in place.
23. A method of supporting concrete or other settable material during construction of a structure employing a shuttering system as claimed in claim 22, the method comprising transporting a plurality of shutter members to a site and transporting a plurality of ties to a site before, on site, assembling the ties and shutter members either before or after aligning a plurality of shutter members to define the edge of a structure and securing the shutter members to a substrate on which the structure is to be formed, the method further comprising the step of pouring concrete or other settable material on the substrate and over the base portion of the shutter member, such that the concrete or other settable material is retained by the walls of the shutter members which are retained upright by the ties extending under tension between the walls and the base portions, with the concrete or other settable material enveloping the ties.