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(11) | EP 0 116 476 A2 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | Securing device |
| (57) A device for securing concrete insert channelling (1) to shuttering (2) comprises
sealing means (7); at least one bolt (10) having a head (13) within the channelling
and a shank extending through an aperture (8) in the shuttering; and a lever (11)
pivotally attached to the bolt shank and having a cam surface (14) which can act (directly
or indirectly) on the shuttering. |
[0001] This invention relates to a device for securing concrete insert channelling to shuttering prior to pouring concrete into the shuttering. By "concrete insert channelling" is meant a structural member comprising a base and two walls, the walls being attached to and extending away in the same direction from the base, the free longitudinally extending edges of the walls having inturned flanges that define between them a slot that will be open to the surface of the concrete. This invention relates to a device intended primarily for securing channelling of the kind described to metal or metal alloy shuttering, though it can be used with shuttering of timber or any other suitable material. Concrete insert channelling can be used in conjunction with numerous readily available fittings to provide supports for electrical and mechanical services, such as cables and pipes, subsidiary structures, such as suspended ceilings; lights, and many other fittings.
[0002] When the concrete insert channelling is used with timber shuttering, it can be nailed into place, but when steel (or other metallic) shuttering is used this is not feasible, and the only reliable technique in current use is the tedious one of using many nuts and.bolts. If the securing is unreliable, the ! channelling may move from its proper position and/or fill with concrete, whereas if a nut and bolt is overlooked when the shuttering is removed, the flanges of the channelling holding it are liable to be bent; any of which renders useless not only the channelling but also the body of concrete in which it was embedded.
[0003] According to the present invention a device for securing concrete insert channelling to shuttering comprises sealing means for location between the inturned flanges of the channel and the shuttering; at least one bolt having a shaped head engageable through the slot of the channelling with the inturned flanges thereof and a shank which then extends between the inturned flanges and through an aperture in the shuttering; and a lever pivotally attached to the bolt shank and having a cam surface adjacent the bolt shank; the arrangement being such that as the lever is pivotted relative to the bolt shank from a released position to a locked position the cam surface area acts (directly or indirectly) on the opposite side of the shuttering to the channelling (the outside) to pull the channelling towards the shuttering and apply sufficient pressure to the sealing means to ensure a seal between the channelling and the shuttering to substantially prevent ingress of concrete or any constituent thereof into the channelling.
[0004] The sealing means is preferably a single strip of material wide enough to engage both flanges of the channelling and apertured for passage of the bolt head(s); however, two separate strips, one for each flange, could be used. Preferably the sealing means is of resilient solid material, such as synthetic or natural rubber or softwood lathing, but non-resilient compressible seals (e.g. of expanded polystyrene or cardboard or even ribbons of a mastic sealant) could be used if desired.
[0005] The bolt head is preferablyy rectangular or approximately so; its shank need not be threaded, though a threaded shank provides a convenient means of adjustment for variations in the thickness and/or the sealing means, as further described below.
[0006] Preferably the shank includes a square or otherwise non-circular portion which can be engaged to hold the bolt against rotation in alternative positions such that its shaped head extends either longitudinally or transversely of the channelling.
[0007] This non-circular portion could be engaged by a non-circular opening directly formed in the shuttering, but preferably the device also comprises a bush which fits in the aperture in the shuttering, has an aperture through which the bolt shank passes, and has a flange or other abutment for engaging the shuttering on the opposite side of the shuttering to the channelling. In this case the cam surface on the lever preferably acts on the bush. Preferably a locking projection, screw or the like which extends into an auxiliary aperture in the shuttering prevents rotation of the bush relative to the shuttering. A portion (or the whole) of the aperture of the bush may then have a non-circular cross-section for engagement with the non-circular part of the bolt. Preferably a helical compression spring is positioned between, and engages, the bush and the bolt head to urge them apart and so disengage the non-circular sections when the lever is in the release position.
[0008] The bush may be of any tough non-metallic or metallic material that will not cause corrosion problems; hard plastics materials are preferred.
[0009] Preferably the lever is connected to the bolt by a pin or pins weak enough to shear under a force higher than will normally be applied to it but less than the force required to cause damage to the channelling; this eliminates risk of the channelling being damaged as a result of the shuttering being removed without releasing the device, and the shear pin(s) can be easily and cheaply replaced. This is both technically better and cheaper than the use of a shear-head bolt.
[0010] The pins or pins may engage directly in holes in the shank of the bolt, but if adjustment is desired it is preferable for the pin or pins to engage in holes in a nut threaded on the bolt; preferably the bolt is slotted and the pin or pins extend into the slot to ensure a correct angular relationship between the pivot axis and the bolt head.
[0011] Preferably means are provided for securing the lever in its locked position; one convenient means when the devices are used in pairs is to locate the levers so that their free ends lie parallel to the channelling and point towards each other is to interlink the two free ends using suitable strapping and/or a tension spring; in other cases an attachment on the shuttering could be used to secure the free end, or a locking pin could be passed through apertures in the lever and the bolt that are aligned when the lever is in the locked position.
[0012] When the channelling has anchors to assist securing the channelling in the concrete formed by stamping our portions of the base of the channelling to leave apertures in the base, preferably these apertures are sealed to substantially prevent ingress of concrete by a cap as described in our pending UK Patent Application No. 8302741 filed lst February, 1983, but alternatively a polystyrene infill in the channelling can be used in the customary way.
[0013] The inturned flanges of the channelling may have series of teeth formed in them. In this case the bolt head preferably has ribs which interengage with the teeth to prevent the bolt sliding longitudinally in the channel, in accordance with our British Patent Serial No. 2050549B.
[0014] The invention includes a method of casting concrete with concrete insert channelling embedded in it using the devices described.
[0016] The invention is further described, by way of example, with reference to the accompanying drawings in which:-
Figure 1 is a cross-sectional view of one form of device in accordance with the invention;
Figure 2 is a cross-sectional view of another form of device in accordance with the invention;
Figure 3 is a view, perpendicular to Figure 2 showing this device with the lever, nut and pins removed;
Figure 4 is a sketch of the nut; and
Figure 5 is a section on V-V in Figure 4.
[0017] Referring first to Figure 1, a length of concrete insert channelling 1 is to be embedded in concrete that will occupy the area above (as drawn) steel shuttering 2. The channelling 1 comprises a base 3, walls 4, inturned flanges 5 and anchors 6 in the form of L-shaped projections pressed from the base of the channelling. A rubber sealing strip 7 extends longitudinally of the channelling 1 and aligned apertures 8,9 in the shuttering 2 and the rubber strip respectively receive the main body of respective fixing devices. The essential elements of this comprise a (threadless) bolt 10 and a lever 11 pivotted together by a shear pin 12. The head 13 of the bolt is rectangular and when rotated through 90° from the position shown passes freely between the flanges 5 of the channelling and preferably through the hole 8 in the shuttering 2 as well, though this is not essential.
[0018] The lever 11 has a cam surface 14 which bears on the underside 15 (outside) of the shuttering 2, through the flange 16 of a nylon bush 17 in the design shown, to tension the bolt 10 when the lever 11 is in the position shown (the locked position). The bolt 10 is formed with a square section 18 and at least the part 19 of the bore of the bush 17 that receives it is of corresponding cross-section, so that relative rotation is prevented when the lever 11 is locked; a screw or other pin 21 holds the bush 17 against rotation with respect to the shuttering 2.
[0019] When, after the concrete has been poured and has set, the device is released by moving the lever 11 to an upright position (the released position), a compression spring 22 urges the bolt 10 upwards until the square section 18 is clear of the bush 17, allowing rotation of the bolt 10 through 90° to a release position, in which position it can be locked in preparation for removal of the shuttering 2; it cannot be locked in any intermediate position. Failure to put the device in the release position before removal of the shuttering 2 results in shearing of the pin 12, without risk to the channelling 1 (or to the shuttering); the remaining parts can been collected and re-assembled with a new pin. The lever 11 can be fixed in the locked position by a spring 23 engaging a hook 24 welded to the shuttering 2; similar means may be used to fix it in its release position, or if a pair of neighbouring devices are arranged with their levers pointing towards each other, they may both be locked by a spring, or strapping, interconnecting their levers.
[0020] The device of Figures 2-5 is similar to that shown in Figure 1 (similar parts have been given the same reference number), except that provision is made for adjustment in the spacing of the pivot from the bolt head 13. The bolt is threaded and receives a nut 26 which is drilled transversely at 27 to provide a pivot axis. The bolt shank is formed with a slot 28, and the shear pins 29, 30 (two are used for convenience) penetrate into this slot 28 through hole 27 in the nut 26 in order to prevent relative rotation between nut and bolt (so that adjustment is available in steps of half a turn).
1. A device for securing concrete insert channelling to shuttering comprising sealing
means for location between the inturned flanges of the channel and the shuttering;
at least one bolt having a shaped head engageable through the slot of the channelling
with the inturned flanges thereof and a shank which then extends between the inturned
flanges and through an aperture in the shuttering; and a lever pivotally attached
to the bolt shank and having a cam surface adjacent the bolt shank; the arrangement
being such that as the lever is pivotted-relative to the bolt shank from a released
position to a locked position the cam surface acts (directly or indirectly) on the
opposite side of the shuttering to the channelling (the outside) to pull the channelling
towards the shuttering and apply sufficient pressure to the sealing means to ensure
a seal between the channelling and the shuttering to substantially prevent ingress
of concrete or any constituent thereof into the channelling.
2. A device as claimed in Claim 1, wherein the sealing means is a single strip of
material wide enough to engage both flanges of the channelling and apertured for passage
of the bolt head(s).
3. A device as claimed in any one of the preceding Claims, wherein the bolt shank
includes a square of otherwise non-circular portion which can be engaged to hold the
bolt against rotation.
4. A device as claimed in Claim 3 comprising a bush which fits in the aperture in
the shuttering, has an aperture through which the bolt shank passes and has a flange
or other abutment for engaging the shuttering on- the opposite side of the shuttering
to the channelling, wherein at least a portion of the aperture of the bush has a non-circular
portion for engagement with the non-circular portion of the bolt shank.
5. A device as claimed in Claim 4, wherein the cam surface on the lever acts on the
bush.
6. A device as claimed in Claim 4 or Claim 5, wherein a locking projection extends
into an auxiliary aperture in the shuttering to prevent rotation of the bush relative
to the shuttering.
7. A device as claimed in any one of Claims 4 to 6, wherein a helical compression
spring is positioned between, and engages, the bush and the bolt head to urge them
apart and so disengage the non-circular sections when the lever is in the release
position.
8. A device as claimed in any one of the preceding Claims, wherein the lever is connected
to the bolt by a pin or pins weak enough to shear under a force higher than will normally
be applied to it but less than the force required to cause damage to the channelling.
9. A device as claimed in Claim 8 in which a portion of the bolt shank is threaded,
wherein the pin or pins engage in holes in a nut threaded on the bolt shank.
10. A device as claimed in Claim 9 in which the threaded portion of the bolt shank
is slotted, wherein the pin or pins extend into the slot to ensure a correct angular
relationship between the pivot axis and the bolt head.