This invention relates to a restraint device which is releasably securable to a flanged support to provide an abutment against which forces applied to the device may react. In particular, the invention relates to such a restraint device for securing to flanged beam elements used as formwor supports in the casting of concrete structures such as walls and soffits.

It has been proposed in GB-A-2133450 to provide a force restraint system including a restraint device releasably securable to a flanged beam wherein the device tilts and jams relative to the beam upon the application of forces to the device.

It is an object of the present invention to provide an improved restraint device which is releasably securable to a flanged support in such manner that it does not rely on tilting relative to the support upon the application of forces to the device and wherein the direct securing of the device to the support at any position along the length of the flange or flanges thereof is facilitated.

In accordance with the invention there is provided a restraint device mountable directly onto a flange of a flanged support comprising at least one planar surface element locatable directly onto a planar face of a said flange; at least one abutment spaced away from the or each said surface element; a pair of opposed clamp arms carried by the device each of which is engageable over a flange edge; means for moving said clamp arms into and

out of clamping engagement with said flange in a direction substantially perpendicular to the plane of the or each said surface element; and means permitting at least one of said clamp arms to move in a direction substantially parallel to the plane of the or each said surface element towards and away from the other clamp arm between an operative position of said clamp arms wherein they are both engaged over a flange edge and clampable to a flange and an inoperative position in which said at least one clamp ^■ arm is disengaged rom a flange edge whereby the device may be directly located on or removed from the flange at a required position thereon.

The restraint device may comprise two said surface elements co-planar with one another and pivotally connected together for movement relative to one another in the plane of said elements, a said clamp arm being associated with each one of said surface elements for movement therewith between said operative and inoperative positions of the clamp arms.

Said pivotal connection may comprise a pivot pin extending between pivot lugs on said surface elements in a plane substantially perpendicular to the plane of the surface elements. Alternatively, said pivotal connection may comprise a spacer element pivotally connected between said surface elements, said spacer element being pivotaϊly connected at each of its ends to a respective one of said surface elements by means of a pivot pin connected to one or more pivot lugs on the spacer element, each said pivot pin extending in a plane substantially perpendicular to the plane of the surface elements.

Alternatively, the restraint device may comprise a single surface element having said clamp arms associated therewith. The said at least one of said arms may be either slidably mounted relative to said element or pivotally mounted relative to said element for movement between said operative and inoperative positions of the clamp arms.

The means for moving said clamp arms into and out of clamping engagement with a flange conveniently comprises a clamping bolt carried by the device in screw threaded engagement with the clamp arm. Preferably each clamp arm is of generally C-shaped configuration for engagement over a flange edge, the upper limb of each arm having an internally threaded hole for receiving a said clamping bolt extending therethrough and the lower limb of each arm being engageable with the underside of a said flange.

The or each said abutment may comprise a first abutment portion of the device extending substantially perpendicular from the or each said surface element; said first abutment portion preferably comprising a planar wall portion, the plane of which is substantially perpendicular to the plane of the or each surface element. The or each said abutment may include an additional abutment portion of the device spaced from said first abutment portion.

Also in accordance with the invention there is provided a force restraint system comprising one or more restraint devices as described in the preceding paragraphs in combination with a flanged support.

Other features of the invention will become apparent from the following description given herein solely by way

of example with reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views and wherein:-

Figure 1 is an isometric view of a restraint device having two co-planar surface elements constructed in accordance with the invention mounted on a twin flanged support beam;

Figure 2 is a further isometric view of the restraint device of Figure 1 taken from a different angle;

. Figure 3 is a further isometric view showing a pair of the restraint devices mounted on a twin flanged beam for providing restraint against forces imposed by a tie rod located parallel to and extending longitudinally of the beam;

Figure 4 is a further isometric view of the restraint device of Figure 1 showing the clamp arms in their inoperative position;

Figure 5 is a similar isometric view to that of Figure 4 but taken from a different angle;

Figure 6 is ^' a further isometric view similar to that of Figure 1 but showing a tie rod inclined relative to the beam;

Figure 7 is an isometric view of a modified form of the device of Figure 1 adapted for mounting on a twin flanged beam having a wider spacing between the flanges than that of the beam of Figure 1;

Figure 8 is a further isometric view of the modified device of Figure 7 showing a tie rod inclined relative to the beam;

Figure 9 is an isometric view of an alternative embodiment of restraint device in accordance with the invention having a single planar surface element and pivotally mounted clamp arms; and

Figure 10 is an isometric view of another alternative embodiment of restraint device according to the invention having a single planar surface element and slidably mounted clamp arms.

Referring to Figures 1 to 6 of the drawings, there is illustrated a restraint device in accordance with the invention having two co-planar surface elements 10 and 12 pivotally connected together by pivot pin 14 at one end thereof for movement relative to one another in the plane of the elements with each said element at the other end thereof carrying a clamp arm 16 thereon. Each clamp arm 16 is of generally C-shaped configuration having a lower limb 18 with an upper surface (preferably serrated or knurled for enhanced gripping) engageable with the undersurface of a flange 20 of a twin flanged beam 22. The upper limb 24 of each clamp arm 16 is provided with an internally threaded through hole within which is engageable a clamping bolt 26 supported with clearance for the threads in an unthreaded aperture in a support lug 28. Each bolt 26 passes through an associated clamp arm upper limb 24 into engagement with the upper face of a surface element 10 or 12.

Each said planar surface element 10 and 12 is of generally rectangular form having a side wall 30

upstanding perpendicularly from one (inner) longitudinal edge thereof and an end wall 32 upstanding perpendicularly from that end of the surface element remote from the pivotal connection 14. Conveniently each surface element 10 or 12 and its two upstanding walls 30 and 32 are formed as an integral casting together with the said support lug 28 which is located within the right angle between the two walls 30 and 32.

As will be clearly seen from Figures 2 and 3, the outer faces of the two end walls 32 are planar and together define an abutment for, for example, a clamping nut 34 screw threadedly engaged on an externally threaded tie rod 36 as shown in Figure 3. The two side walls 30 each have an arcuate recess 38 therein which recesses together provide a further abutment for a tie rod bush 40 and locating lug 42 for an inclined tie rod as is shown in Figure 6.

Figure 6 of the drawings illustrates a restraint device of the same type as illustrated in Figures 1 to 5 but wherein an inclined tie rod is engaged with the recessed abutments in the upper surfaces of the side walls 30 by means of an internally threaded bush 40 and locating lug 42 of circular cross section, each projecting free end of which is engageable within a said arcuate recess 38. Alternatively, the bush 40 may have a clearance hole for the tie rod to pass freely therethrough and provide an abutment for a tie rod nut or the like to bear against.

In Figures 1 and 2, the restraint device is shown mounted on the upper planar surfaces of the flanges 20 of a twin flanged beam 22 of the type which may be provided as a formwork support in the casting of concrete

structures such as walls and soffits. In Figures 1 to 3, each restraint device is shown clamped to the beam flanges 20 by means of the clamp arms 16, the clamp bolts 26 being screwable downwardly through the upper limb 24 of each clamp arm to engage the upper face of a respective element 10 or 12 and to bring the upper surface of the lower limb 18 into clamping engagement with the undersurface of a flange 20 thereby clamping the two co-planar surface elements 10 and 12 of the device to the flanges with the co-planar under surfaces of the elements 10 and 12 in firm contiguous contact with the co-planar upper surfaces of the flanges .20.

In accordance with the invention, each device is readily securable to and removable from the beam 22 directly at a predetermined position and this is accomplished in the embodiment of Figures 1 to 6 by the provision of the pivotal connection between the two co-planar surface elements 10 and 12. Thus, to disengage the device from the beam, the clamping bolts 26 are unscrewed thereby loosening each clamp arm 16 from clamping engagement with a beam flange 20 at which time the two surface elements 10 and 12 together with their associated clamp arms 16 may be pivotted apart in the plane of the beam flanges to the position shown in Figures 4 and 5. In this position, it is clear that each restraint device may be readily removed directly" from the beam flanges whilst, conversely, from the inoperative position shown in Figures 4 and 5, the device may be located directly on the beam at a required position and the surface elements 10 and 12 then swung towards one another into the operative clampable positions of the clamp arms 16.

In this embodiment illustrated in Figures 1 to 6, the pivotal connection between the two surface elements 10 and 12 comprises a single pivot pin extending perpendicular to the plane of the surface elements between cooperating pivot lugs 44 extending outwardly of the side wall 30 of each surface element 10 and 12. However, the device of Figures 1 to 6 may be modified as shown in Figures 7 and 8 by the provision of a spacer link comprising two parallel link bars 46 pivotally connected at each of their ends between the pivot lugs 44 of the two surface elements 10 and 12. The length of the spacer link may be adapted to any particular flange spacing on a twin flanged beam or between two adjacent beams upon which the restraint device is required to be mounted whilst, as will be appreciated, the benefits of direct engagement with and removal from the beam flanges are retained.

An alternative embodiment of restraint device constructed in accordance with the invention is shown in Figure 9 of the drawings wherein the device comprises a single planar surface element 50 of generally rectangular form having a buttressed upstanding end wall 52 the outer planar face of which provides an abutment for, for example, a threaded tie rod clamping nut of the type shown in Figure 3. In this embodiment, a pair of clamp arms 16 are pivotally mounted on the surface element 50 by means of a single pivot connection 54 so as to be pivotable between an operative position as shown by the right hand arm of Figure 9 and an inoperative position as shown by the left hand arm. Each clamp arm proper 16 comprises a C-shaped member of similar form to the corresponding clamping arm 16 described and illustrated with respect to the embodiments of Figures 1 to 8. Each such clamp arm proper is carried on the end of a cranked

support bar 56, the other end of each such bar being pivotally connected at 54 as aforesaid to the surface element 50. Thus, in accordance with the invention, the restraint device is readily and directly mountable on and disengageable from a flange of a flanged beam at any required position when at least one of the clamp arms 16 is in its inoperative position. After both of the clamp arms have been pivotted to their operative positions (i.e. as shown by the right hand arm of Figure 9) the device may be clamped to the beam in a similar manner to that described with reference to the embodiment of Figures 1 to 8.

A further alternative form of restraint device is shown in Figure 10 wherein, again, the device is provided with a single planar surface element 50 of generally rectangular form having an upstanding end wall 52 providing an abutment. In this embodiment each clamp arm 16 is again of generally C-shaped form and includes a support bar 58 extending longitudinally of the upper limb 24 for sliding engagement relative to the surface element 50. Each of the support bars 58 passes through a cooperating aperture 60 provided in each of a pair of parallel walls 62 upstanding centrally of the support element 50 whereby the clamp arms 16 are supported on and slidably movable in the plane of the surface element between operative and inoperative positions. In the inoperative position of at least one of the clamp arms, the device may be readily and directly mounted on or disengaged from the beam flange at a required position.

Each of the support bars 58 is provided with a dependant lug 64 at its free end whereby it is retainable relative to the surface element 50 but freely slidable between the operative and inoperative positions.

It will of course be appreciated that a restraint device in accordance with the invention may be readily and directly mounted on and disengaged from either a twin flanged single beam or two adjacent flanged beams or a single flanged beam for example, a beam of simple

I-section form. The relatively large planar undersurface area of the or each surface element of the device ensures good, non-tilting, frictional engagement of the surface with a beam flange when the device is clamped to the flange by means of the clamp arms. The ability of the clamp arms to be movable from their clamping operative positions to their inoperative positions clear of the flange edges enables the device to be mounted on or disengaged from a required position on a beam in a direct manner without the device having to be initially engaged about the beam flange or flanges from one end thereof and then slid to the required position.

As particularly illustrated in Figures 3, 6 and 8, the restraint device of the invention can form part of a force restraint system against forces transmitted to the device by a tie rod abutted against either the end walls 32 or recesses 38 in the side walls 30. However, the restraint device may ^■ also be utilised in other types of force restraint systems e.g. it can be used as an end stop on a flanged support.