GB2146944A

GB2146944A - Covers and frames

Info

Publication number: GB2146944A
Application number: GB08423648A
Authority: GB
Inventors: Clive Bowley
Original assignee: Dover Engineering Works Ltd
Current assignee: Dover Engineering Works Ltd
Priority date: 1983-09-19
Filing date: 1984-09-19
Publication date: 1985-05-01
Also published as: GB8423648D0; GB8325048D0; GB2146944B

Abstract

A method of manufacturing a hinged cover and frame unit, e.g. a hinged gulley grate and frame unit, comprises forming a cast iron gulley grate (1) with its opposite sides (4) each recessed at (14) to provide seating flanks (15) and pivot recesses (3) in the sides (4) to one end of the respective recess (14), using the grate sides (4) to define part of a frame mould, and pouring a hardenable material, e.g. glass reinforced concrete, into the mould so that it will constitute the frame (2) when solidified and have opposite edges (16) seating the grate flanks (15) and integral pivot bosses (5) pivotally engaging in the grate pivot recesses (3). <IMAGE>

Description

SPECIFICATION Covers and frames This invention relates to covers and frames.

According to the invention there is provided a method of manufacturing a hinged cover and frame unit comprising forming a cover with pivot means at opposite sides thereof, using opposite side regions of the cover inluding said pivot means to define part of a mould cavity, said side regions of the cover being those which are to seat against the frame in use, and introducing a hardenable material when in a flowable condition into the mould cavity so that it will constitute the frame when solidified and have a contour conforming to said side regions of the cover and the pivot means thereat which define said part of the mould cavity, by which said frame will have opposite side regions conforming to the contour of, and seating, the opposite side regions of the cover and integral pivot means complementary to,and pivotally mating with, said pivot means of said cover.

A particular cover to which the invention is applicatble is a hinged gulley grating. Such a gulley grating and its frame have traditionally been made of cast iron. The hinged cast iron grating is prone to rocking under traffic because the hinge facility does not permit the accepted non-rock principles of design to be incorporated. Conventionally, the grating is hinged to its frame by means of steel pins or has integral pivot members that locate into preformed recesses in the frame. In both cases there is a danger of intermetallic corrosion and detritus build up around the hinge area thus imparing the ease of operation in service. Certain designs are also such that the hinged grating can be unlawfully removed from its frame.

By means of the invention, a cover and frame unit is obtained with the cover pivoted in the frame against removal therefrom by moulding the frame around the cover. The moulding process is not only inexpensive but results in the frame being perfectly matched to the cover at those surfaces which seat the cover so that the pivoted cover makes a non-rocking fit in the frame. The process is applicable to other types of frames as will be realized by those skilled in the art and not just to those seating a gulley grating.

In order that the invention may be well understood there will now be described an embodiment thereof, given by way of example, reference being had to the accompanying drawings, in which: Figure 1 is a perspective view of a pivotal gulley grate mounted in a frame; Figure 2 is a plan view of the same grate and frame; Figure 3 is a section along line Ill-Ill of Figure 2 taken during manufacture; and Figure 4 is a section along line IV-IV of Figure 2 also taken during manufacture.

A gulley grate 1 of cast iron is hinged to its glass reinforced concrete frame 2 by means of a pair of pivot connections formed by pivot recesses 3 in the opposite sides 4 of the grate receiving pivot bosses 5 integral with the frame.

In the manufacture of the frame 2, the grate 1 is placed in an outer shutter 6, and an inner shutter 7 is located on the outer shutter and upon the grate, the assembly then constituting a mould into which glass reinforced concrete can be poured which, when solidified, will conform in the configuration to the mould surfaces. Thus, the opposite side bars 8 of the frame 2 will be moulded, not only between the outer shutter 6 and the inner shutter 7, but also against the opposite sides 4 of the grate 1 which constitute inner mould surfaces. Since the pivot recesses 3 are formed in the grate sides 4, the liquid concrete will flow into those recesses to form the pivot bosses 5, one at each of the opposite sides of the grate 1, thereby to hinge the grate in the frame 2 by the pivotal engagement of the bosses 5 in the pivot recesses 3.In the moulding process, it is to be noted that the front bar 9 and back bar 10 of the frame 2 are not directly moulded to the grate 1 since the inner shutter has a front region (not shown) and a back region 11 both of which are interposed between the grate and the outer shutter 6, so that the front and back bars are fully moulded between the two shutters. Thereby, a small gap 12 and a larger gap 13 are left between the front bar 9 and the back bar 10, respectively of the frame 2 and the grate 1 to provide clearance permitting free upward pivotal movement of the grate through at least 90 degrees and extra drainage of surface water.

The opposite sides 4 of the grate 1 are recessed at 14 to provide multi-angled flanks 15 at the opposite ends of each recess which mould corresponding ledges 16 on the side bars 8 of the frame 2.

The frame ledges 16 provide the seating surfaces for the grate 1, and it is upon those ledges that the grate will rest when pivoted from its open position downwardly to close against the frame 2. When seated against the frame 2, the grate 1 makes a non-rocking fit therewith at the juxtaposed grate flanks 15 and the frame ledges 16 since the two make a perfect fit because the former constituted the mould surfaces for the latter.

The "vertical" faces 17 and 17a of the grate sides 4 are slightly inclined inwardly from the top face 18 of the grate 1 so as to form correspondingly sloped "vertical" faces on the frame 2 which will assist in locating the grate in its closed position and not inhibit its pivotal movement when being raised. The vertical faces 17b of the grate sides 4, in which the pivot recesses 3 are formed, are, though, truly vertical.

To ensure that the grate 1 will freely pivot in the frame 2, a thin sleeve (not shown) of some suitable material could be inserted into each grate pivot recess 3 before the moulding operation so that the frame pivot bosses 5 will mould to the inside diameter of the sleeve and hence be slightly smaller than that of the pivot recess. If the sleeve material was such that it would degrade in use, such as polystyrene, the pivot bosses 5 would then have clearance within the pivot recesses 3 to allow easy pivoting of the grate 1. Alternatively the sleeve material could be resilient, preferably of a plastics ma terial, in which case the grate 1 would freely pivot within the sleeve.Preferably, the sleeve would be flanged at one end so that when it is inserted into the respective recess 3 the thin flange would lie against and cover the entire surface of the associated vertical face 17b of the grate side 4 to act as a degradable or resilient shim between the grate side and the frame side bar 8 and so further ease the pivotal movement of the grate 1.

In the moulding operation, the outer shutter 6 carrying the inner shutter 7 and the grate 1 would be stood on a suitable moulding table which would be vibrated by conventional means to ensure even filling of the mould cavity. The inner and outer shutters could both be of polystyrene in which event the cast iron grate and the concrete frame would be stored as a unit and transported within the shutter assembly which acts to protect the frame and which would be broken away on site.

Alternatively, the shutters could be of a silicone or polyurethane rubber peelable away from the moulded concrete frame and capable of use a multiple number of times.

In summary, the process produces a pivotal grate in a concrete frame with the pivot connections therebetween formed in the frame moulding operation to provide positive fulcrum points positively locating the grating and preventing its unlawful removal from the frame. The frame and its pivot bosses are integral and constitute a onepiece, unitary structure with the pivot bosses automatically accurately located relative to the seating surfaces of the frame by the moulding process so that the pivotal grate will make a perfect non-rocking seating fit upon those surfaces preventing build up of extraneous matter therebetween and at the pivot connections.

As an alternative, the grate 1 could have outwardly projecting pivot bosses on each of its opposite sides which would mould, and be pivotally located in, pivot recesses formed in the side bars of the frame 2. Again, suitable bearing sleeves could be used, this time mounted on the grate pivot bosses prior to the moulding process.

Although glass reinforced concrete has been specifically mentioned as the material from which the particular form of frame described is moulded, it will be understood that concrete reinforced by steel fibre or epoxy resin could be used and, indeed, depending upon the use to which the cover and frame unit is to be put, other materials which can be cast or moulded such as metal alloys or synthetic plastics may be utilized.

Claims

1. A method of manufacturing a hinged cover and frame unit comprising forming a cover with pivot means at opposite sides thereof, using opposite side regions of the cover including said pivot means to define part of a mould cavity, said side regions of the cover being those which are to seat against the frame in use, and introducing a hardenable material when in a flowable condition into the mould cavity so that it will constitute the frame when solidified and have a contour conformin g to said side regions of the cover and the pivot m ans thereat which define said part of the mould cavity, by which said frame will have opposite side regions conforming to the contour of, and seating, the opposite side regions of the cover and integral pivot means complementary to, and pivotally mating with,said pivot means of said cover.

2. A method as claimed in claim 1, wherein the pivot means of the cover are pivot recesses, and the pivot means of the frame are pivot bosses pivotally engaged in said pivot recesses.

3. A method as claimed in claim 1, wherein the pivot means of the cover are pivot bosses, and the pivot means of the frame are pivot recesses pivotally receiving said pivot bosses.

4. A method as claimed in any of the preceding claims, wherein a bearing sleeve is applied to each of the pivot means of the cover before the hardenable material is introduced into the mould cavity so that the pivot means of said frame will be moulded to the contour of the bearing sleeves.

5. A method as claimed in claim 4, wherein the bearing sleeves are of a material which will degrade in use.

6. A method as claimed in any of the preceding claims, wherein the opposite side regions of the cover are each recessed to provide multi-angled flanks at the opposite ends of each recess which mould corresponding ledges on the sides of the frame, said ledges defining seating surfaces on which the cover will rest when pivoted to a closed position in the frame.

7. A method as claimed in any of the preceding claims, wherein the hardenable material is liquid concrete.

8. A method as claimed in claim 7, wherein the concrete is reinforced by glass fibre, steel fibre or epoxy resin.

9. A method as claimed in any of claims 1 to 6, wherein the hardenable material is a metal alloy or a synthetic plastics material.

10. A method as claimed in any of the preceding claims, wherein the cover is of cast iron.

11. A method as claimed in any of the preceding claims, wherein the cover is a gulley grate.

12. A method of manufacturing a hinged cover and frame unit substantially as herein described with reference to the accompanying drawings.

13. A hinged cover and frame unit manufactured by a method as claimed in any of the preceding claims.