GB2209782A

GB2209782A - Drainage duct

Info

Publication number: GB2209782A
Application number: GB8721335A
Authority: GB
Inventors: Dennis Barker
Original assignee: Wade International Ltd
Current assignee: Wade International Ltd
Priority date: 1987-09-10
Filing date: 1987-09-10
Publication date: 1989-05-24
Anticipated expiration: 2007-09-10
Also published as: GB8721335D0; GB2209782B

Abstract

A drainage duct has a channel member 10 and a plurality of grates 17 which fit between lips 14 of the channel member, and bear on flanges 13 thereof. Each lip 14 has a longitudinally extending rib 16 projecting laterally inwardly towards the opposed lip, and each grate has grooves 21 formed in its opposed side edges, in which grooves are received the ribs 16. Each grate is thus restrained against removal from the channel member, and a separate locking arrangement is provided for the last-to-be-fitted grate. <IMAGE>

Description

DRAINAGE DUCT This invention relates to a drainage duct assembly suitable for installation for example in the ground, in a concrete slab or the like, to allow the drainage of surface water away from the area of installation.

A known form of drainage duct assembly for installation in the ground, within in a concrete floor slab or the like to allow the drainage of surface water away from that area comprises a generally U-shaped channel member for installation so that the upper edge.

of the channel webs are substantially at ground level, a plurality of grates being laid end-to-end over the channel following the installation thereof. The grates allow water to enter the channel, but prevent solid objects greater than some predetermined size from passing through the grates into the channel. Often the grates have to be able to withstand vehicular traffi passing thereover, and so such grates must be of a sufficient strength having regard to the intended service for the drainaqe duct assembly as a whole.

In the case of a very large drainage duct assembly including relatively massive grates, it may not be necessary individually to secure the grates to the channel member for the weight of each grate may be sufficient to ensure that the grate remains in the required position. In the case of smaller drainage ducts, each grate may be relatively light and so it may be desirable to secure each grate individually to the channel, so as to prevent the dislodgement thereof for example by traffic passing thereover. Securing grates in this way also reduces the likelihood of vandalism.

A known technique for securing grates to a channel member is to provide in each grate at least a pair of holes located one each of two opposed sides, whereby each grate may be secured in the desired position by drilling through the holes in the grate into a flange ofthe channel member, and then fitting self-tapping screws or similar fasteners through the holes in the grates and into the drilled holes in the flange of the channel member. Such a fitting technique is however relatively slow and laborious to install and moreover has the disadvantage that should the grates be removed for example for cleaning of the channel member, the likelihood is that the screws will not be re-fitted when the grates are replaced.

It is an object of the present invention to provide a drainage duct which at least mitigates the disadvantages discussed above, for the known forms of drainage duct assembly. In particular, it is an aim of the invention to provide a drainage duct where each grid may be locked securely in the required position, in a rapid and simple manner.

According to the present invention, there is provided a drainage duct assembly comprising an elongate channel member having a flange at or adjacent the upper edge of each side wall of the channel member, and a plurality of drainage grates each adapted to span the channel member by resting on the flanges whereby a plurality of such grates may be laid end-to-end to cover the channel member, each grate having a groove formed along each of a pair of opposed side edges which grooves are inter-engageable with laterally projecting lugs provided on the channel member adjacent the flanges thereof, whereby a grate may be engaged with the flanges and then slid longitudinally of the channel member to its required position whereat lifting of the grate is restrained by inter-engagement of the lugs and grooves.

It will be appreciated that with the drainage duct assembly of the present invention the securing of the grates to the channel member is performed in a rapid and simple manner, without the need to provide separate fastenings which must individually be fitted. Thus, once a channel member has been laid in the ground at the required position, the drainage duct may be completed merely by engaging each grate with the channel member and sliding the grate along the length of the channel member to its required final position. To prevent subsequent removal of any of the grates, it may be necessary to provide a locking arrangement for the last grate to be fitted to the channel member, whereby removal of that last grate may be prevented.In turn, that prevents the removal of previously-fitted grates, by preventing those grates being slid back from their final position to the position at which they may be removed from the channel member.

Provided that when the channel member has been installed in the ground access may be had to at least one end of the channel member, all of the grates may be fitted from that one end, the grates being slid in turn along the channel member from that one end to the required final position. For a case where access cannot be gained to the end of the channel member, a region of the channel member may have no lugs present for a length at least equal to the length of a grate. In this way, the grates may be lowered vertically on to the flanges in that region and then may be slid longitudinally to the required final positions. The last grate to be fitted to the channel member must lie in the region where there are no lugs, and should be secured to the channel member by some appropriate fixing means.The region where no lugs are present need not necessarily be at one end of the channel member: conveniently, that region could be approximately mid-way along the length of the channel member, whereby grates may be slid longitudinally in each direction from that region.

In a particularly preferred embodiment of the present invention, a series of opposed pairs of lugs are provided along the length of the channel member, with a clear spacing between each pair of lugs of not less than the length of each grate. In this way, each of the plurality of grates may be engaged with the channel member by being lowered to engage the flanges between the two pairs of lugs nearest to the required final position for that grate, whereafter the grate is slid longitudinally of the channel member through a relatively small extent to achieve the final position for that grate.

When all of the grates have been assembled with the channel member, the last grate fitted to the channel member must be secured in position socks thereby to lock all of the grates against removal. Such securing of the last grate may be achieved by drilling into the channel member, through pre-formed holes in the grate, and then fitting screw-threaded fastenings such as self-tapping screws through the holes in the grate, into the drilled holes in the channel member. A more preferred form of locking arrangement for the last grate is to provide a locking bar below the last grate, which locking bar is carried by a screw extending centrally through the grate, the bar having a length shorter than the diagonal dimension of the grate, but longer than the side length of the grate. To use such a locking arrangement, the locking bar is arranged diagonally of the grate which is then lowered into position between two other grates previously fitted to the channel member. Then, the locking bar is turned to lie parallel to the length of the channel member, such that the end portions of the locking bar engage below the two adjacent grates. The screw carrying the locking bar may then be tightened to raise the locking bar into firm engagement with the undersides of all three grates, so as to restrain further rotation of the locking bar until the screw is loosened once more. Preferably, the screw is arranged so that the locking bar remains captive on the screw, even when the screw has been loosened.

The channel member preferably is formed from sheet metal, by an appropriate bending operation. The channel member thus may define a base wall with two upstanding sides walls, with out-turned flanges along the upper edges of the side walls. An upwardly-extending lip may be provided along the outer edge of each flange, the grates fitting between the lips when bearing on the flanges. For such a channel member, the lugs would be provided along the inwardly-facing surfaces of the lips, the lugs either being separately formed and then attached to those lips, or possibly formed integrally with those lips. The grates themselves preferably are also metallic, formed for instance by a casting or fabricating operation to have the required overall shape and profile.

By way of example only, one specific embodiment of drainage duct assembly of this invention will now be described in detail, reference being made to the accompanying drawings, in which: Figure 1 is a vertical cross-sectional view through the embodiment of drainage duct assembly; Figure 2 is a plan view of a grate employed in the drainage duct assembly of Figure 1; and Figure 3 is a longitudinal vertical section through a portion of the drainage duct assembly illustrated in Figure 1.

The embodiment of drainage duct assembly shown in the drawings includes a drainage channel 10 formed from sheet metal by a suitable bending operation so as to have a generally U-shaped cross-section including a base wall 11 and a pair of upstanding side walls 12. Along the upper edge of each side wall 12 there is formed an outwardly directed flange 13, and in turn each flange 13 has an upstanding lip 14 along its outer edge. At a suitable point along the point of the base wall 11 there is provided a circular outlet connector 15, whereby water collecting in the channel 10 may be led away to a suitable drain.

Attached to the inwardly-directed surfaces of the lips 14 are pairs of opposed lugs 16, each lug being in the form of a length of round bar attached to the lip, for example by welding. The longitudinal spacing between opposed pairs of lugs is slightly greater than the internal dimension between the lips 14, and each lug has a length of about one quarter of that dimension.

The channel 10 is used with a plurality of grates 17, each of generally square shape and manufactured by a metal casting technique so as to have a substantially flat upper surface 18 perforated with a plurality of openings 19. The length of each side of each grate is substantially equal to the internal dimension between the lips 14 of the channel 10.

Each vertical side edge 20 of each grate 17 has formed therealong a channel 21 appropriately dimensioned to allow the accommodation therein of a lug 16, when the grate 17 rests on the flanges 13 of the channel 10, as illustrated in Figure 1. The corner regions 22 may be cut away on the underside of the grate, as illustrated in broken lines in Figure 2, and also fixing holes 23 may be formed one in each corner of the grate.

The drainage duct assembly described above is used for example by sinking the channel 10 in a concrete floor so that the upper edges of the lips 14 are substantially flush with the concrete surface. Prior to fixing the channel, the outlet connector 15 should be connected to a suitable drain leading away from the area to be drained. Then, the grates 17 are lowered between the lugs 16 so as to engage the flanges 13, and the grates are then slid longitudinally of the channel member 10 through a relatively short distance such that the lugs 16 engage in the channels 21 of the grates.

When so engaged, the grates 17 cannot be lifted out of the channel member.

The length of the channel member and final positions of the grates should be such that the last grate to be fitted to the channel member to complete a run of the drainage duct fits neatly between two already-fitted grates and also between two pairs of lugs 16. In order to allow that last grate to be secured in position, it may be provided with a locking bar 25 (Figure 3) carried on a screw 26 extended through the central opening 27 of the grate. The locking bar 25 should have a length shorter than the diagonal dimension of the grate, but longer than the length of a side edge of that grate. The grate may then be fitted in position between two other grates when the locking bar lies diagonally, but the locking bar may then be turned to lie parallel to the length of the channel member, so that the end portions of the bar engage under the two adjacent grates. The screw 26 is then turned to clamp the locking bar 25 to the under sides of the three adjacent grates, as illustrated in Figure 3. The bar 25 may have a pair of pegs 28 to engage the grate and resist the turning of the bar as the screw is tightened.

The last grate to be fitted to the channel member cannot subsequently be withdrawn, until the screw 26 is turned to loosen the locking bar 25 and the bar is turned to lie diagonally once more.

Claims

1. A drainage duct assembly comprising an elongate channel member having a flange at or adjacent the upper edge of each side wall of the channel member, and a plurality of drainage grates each adapted to span the channel member by resting on the flanges whereby a plurality of such grates may be laid end-to-end to cover the channel member, each grate having a groove formed along each of a pair of opposed side edges which grooves are inter-engageable with laterally projecting lugs provided on the channel member adjacent the flanges thereof, whereby a grate may be engaged with the flanges and then slid longitudinally of the channel member 'to its required position whereat lifting of the grate is restrained by inter-engagement of the lugs and grooves.

2. A drainage duct according to claim 1, wherein the laterally projecting lugs extend for substantially the whole length of the channel member, all of the grates being fitted thereto from one or other end of the channel member.

3. A drainage duct according to claim 1, wherein a region of the channel member has no lugs present, for a length at least equal to the length of a grate.

4. A drainage duct according to claim 1, wherein a series of opposed pairs of lugs are provided along the length of the channel member, with a clear spacing between each pair of lugs of not'less than the length of each grate.

5. A drainage duct according to claim 3 or claim 4, wherein the grate to be fitted to the channel member in the region where there are no lugs is provided with fixing means to secure that grate to the channel member.

6. A drainage duct according to claim 5, wherein the fixing means comprises pre-formed holes in the grate, in combination with screw-threaded fastenings adapted to engage with the channel member.

7. A drainage duct according to claim 5, wherein the fixing means comprises a locking bar below the last grate, which locking bar is carried by a screw extending centrally through the grate, the bar having a length shorter than the diagonal dimension of the grate, but longer than the side length of the grate.

8. A drainage duct according to claim 7, wherein the screw remains captive on the locking bar, even when loosened.

9. A drainage duct according to any of the preceding claims, wherein the channel member is formed from sheet metal, by an appropriate bending operation.

10. A drainage duct according to claim 9, wherein the channel member comprises a base wall with two upstanding side walls, there being out-turned flanges along the upper edges of the side walls.

11. A drainage duct according to claim 10, wherein there is an upwardly-extending lip provided along the outer edge of each flange, the grates fitting between the lips when bearing on the flanges.

12. A drainage duct according to claim 11, wherein the lugs are provided along the inwardly-facing surfaces of the lips, the lugs either being separately formed and then attached to the lips, or formed integrally with the lips.

13. A drainage duct substantially as hereinbefore described, with reference to and as illustrated in the accompanying drawings.