GB2199357A

GB2199357A - Manhole cover and frame assembly

Info

Publication number: GB2199357A
Application number: GB08630673A
Authority: GB
Inventors: Anthony Charles Elmer
Original assignee: BRICKHOUSE DUDLEY Manufacturing
Current assignee: BRICKHOUSE DUDLEY Manufacturing
Priority date: 1986-12-23
Filing date: 1986-12-23
Publication date: 1988-07-06
Anticipated expiration: 2006-12-23
Also published as: GB2199357B; GB8630673D0

Abstract

A manhole cover and frame assembly comprises a frame, which affords an access opening, a cover adapted to be received in the frame to close the access opening, and a closure plate co-operating with the frame to retain the cover within the access opening, the closure plate having formed around its periphery (12) a resilient gasket (20). Also disclosed is a method of securing a resilient elastomer to a member made of GRP material, said method comprising moulding the member and before the GRP material has set, positioning the resilient elastomer, and then allowing the GRP to set. <IMAGE>

Description

Title: "Cover and frame assembly" Description of Invention This invention relates to a cover and frame assembly of the kind (hereinafter referred to as of the kind specified) comprising a frame which affords an access opening, the frame being adapted to be embedded in or secured on the ground above a manhole, sewer, sump or the like, and a cover adapted to be received in the frame to close or substantially close the access opening.

Particularly where the access opening provides access to a sewer beneath, it is usual to provide a closure plate in the access opening, the closure plate being made of a material such as glass reinforced plastics (GRP) which is resistant to acidic fumes which tend to rise from the sewer. The plate thus provides some protection for the metalwork of the assembly.

In dusty environments such as in hot desert countries, the closure plate performs a further or alternative function namely to resist the amount of dust and sand which can pass through the access opening.

It is an object of the present invention to provide a new or improved cover and frame assembly of the kind specified.

According to a first aspect of the invention we provide a cover and frame assembly of the kind specified including a closure plate co-operating with the frame to retain the closure plate within the access opening, the closure plate having formed around its periphery a resilient gasket.

Thus the seal between the closure plate and the frame is improved compared with known arrangements in which the closure plate simply rests on more or more inwardly extending formations of the frame.

Preferably the closure plate is of generally similar outer configuration to the configuration of the access opening, the gasket closing a space which would otherwise exist between the closure plate and a wall of the access opening.

In one arrangement, the plate comprises a Glass Reinforced Plastics (GRP) material, which is resistant to acidic fumes, although where the cover and frame assembly is to be used over a storm drain for example, or in another application where there are no acidic fumes, the closure plate could be made of any other desired material. In this latter case, the closure plate would only be effective to prevent or at least reduce the ingress of sand and the like through the access opening.

Where the plate is made of a GRP material, the gasket may be formed integrally with the plate by attaching the gasket to the plate during formation of the plate. For example, the plate may be moulded and the gasket positioned before the GRP has set (as herein defined).

By "set" we mean that the chemical constituents of the GRP material have reacted to a sufficient degree that the closure plate can be used for its final intended purposes.

Preferably the periphery of the GRP closure plate has first cooperating formations and the gasket has second cooperating formations, the first and second co-operating formations engaging as the gasket is positioned to provide added resistance to separation of the gasket from the plate.

In an alternative arrangement, the gasket may be retained in position simply by the engagement of first and second co-operating formations and/or the gasket may be adhered in position with a suitable adhesive.

The frame of the assembly may have a continuous flange which extends inwardly around the access opening, the gasket, in use, co-operating with the flange.

It will be appreciated therefore that the closure plate acts as a plug to close the access opening. To improve the sealing effect between the flange and the closure plate, the outer periphery of the gasket may have an inclined surface which engages with the flange in the manner of a wedge as the closure plate is inserted in the access opening from above.

The gasket may comprise any suitable resilient elastomer.

The invention may be applied to a frame affording a round, square, rectangular, or other shaped access opening as required.

According to a second aspect of the invention we provide a method of securing a resilient elastomer to a member made of GRP material, comprising moulding the member and prior to the GRP material setting (as herein defined) positioning the resilient elastomer, and then aliowing the GRP to set.

If desired, the GRP member may be moulded with first co-operating formations which engage with second co-operating formations of the resilient elastomer to provide added resistance to separation of the GRP member and the resilient elastomer.

The method according to the second aspect of the invention may be applied be to a cover and frame assembly of the first aspect of the invention, for securing the gasket to the periphery of the closure plate.

The invention will now be described with the aid of the accompanying drawings in which: FIGURE I is a plan view of a closure plate for use in a cover and frame assembly according to the first aspect of the invention.

FIGURE 2 is a side cross sectional view of the plate of Figure 1.

FIGURE 3 is an enlarged cross sectional view through a gasket which is shown in position in Figure 2, and, FIGURE 4 is an enlarged cross sectional view through a part of the closure plate of Figures 1 and 2, and showing part of the frame of the cover and frame assembly.

Referring first to figures 1 and 2, a closure plate 10 comprises a generally tray-like construction having a central region II and generally continuous upstanding side region 12. The plate 10 is made in one piece by moulding, with integrally provided strengthening ribs 13 accross the central region, and lifting formations 14.

The overall outer configuration of the plate 10 is substantially similar to the inner configuration of an access opening of a generally rectangular cover and frame assembly of the kind specified.

The frame of the assembly with which the cover plate 10 is to be used, has internal corner fillets which provide bearing blocks on which one of a pair of triangular cover parts may rest and this is why the corners of the plate 10 are of the configuration shown.

The side region 12 of the cover plate 10 is shown in more detail in figure 4.

The side region 12 has a generally upstanding part 15 which terminates in an outwardly extending flange 16. The distance between opposite points of the upstanding part 15 is just less than the corresponding dimension of an access opening 17 of the cover and frame assembly with which the closure plate 10 is used i.e. the corresponding dimension of a mouth 5 defined by the frame of the assembly. Thus ordinarily there would be a space between the wall of the mouth 5 and the upstanding part 15. However, this space is closed with a gasket 20 which lies between the part 15 and the flange 16, and the mouth 5. The gasket 20 extends continuously around the entire periphery of the cover plate 10 (although there is necessarily a join between ends of the gasket 20 at some point).

The actual configuration of the gasket is shown in cross section more clearly in figure 3.

The gasket 20 has a depending part 21 and a sideways extending part 22.

The depending part 2 1 has an inclined outer wall 23, so that when the closure plate 10 is placed in the access opening 17 from above, the gasket 20 acts in the manner of a wedge to more tightly engage with the mouth 5 of an inwardly extending flange 24 (see figure 4) of the frame.

The gasket 20 has co-operating formations comprising a pair of ribs 25, and a plurality of re-entrant grooves 26 which co-operate with corresponding co-operating formations moulded integrally with the closure plate 10 as shown in figure 4 to retain the gasket 20.

The sideways extending part 22 of the gasket 20 provides a further depending part 27 which will engage the upper surface of the flange 24 of the frame if the closure plate is urged downwardly a sufficient amount (further than shown in figure 4).

The gasket 20 comprises a resilient elastomer and is preferably formed integrally with the side region t2 of the closure plate 10 by the following method.

The closure plate 10 is moulded in glass reinforced plastics material, and just before the material has set, the resilient elastomer 20 is positioned as shown, whilst the closure plate 10 continues to set.

Utilising this method it has been found that strong resistance to separation of the gasket 20 from the closure plate 10 is achieved.

However if desired, other methods could be used to form the gasket 20 with the side region 12 of the closure plate 10. For example, the co-operating formations 25 and 26 of the gasket, co-operating with the corresponding cooperating formations of the side region 12 of the closure plate may be sufficient to retain the gasket 20 in position. Alternatively and/or in addition, the gasket 20 may be adhered in the position shown.

In conventional constructions which utilise a closure plate similar to closure plate 10, but without the gasket 20, it is common practice to secure the closure plate 10 to the frame of the cover and frame assembly with screws or the like.

In the present instance, the outwardly extending flange 16 of the closure plate 10 is also formed with a plurality of openings 30 which may receive fasteners to enable the closure plate 10 to be secured relative to the frame if required.

Various modifications may be made without departing from the scope of the invention.

In the example described, the closure plate 10 is intended to act in the manner of a plug to close the access opening 17 of the frame of the cover and frame assembly of which it is used. The plate 10 being made of GRP material is thus resistant to acidic fumes and the like which can rise from a sewer beneath the access opening although could be made of another acid resistant material if required. In another application, for example where the plate is to be used above a storm drain or the like in which acidic fumes are not present, the plate could be made of other materials if required.

Although as shown, the gasket 20 has an outer inclined surface 23, if desired, the gasket could be of an alternative configuration provided that the gasket acts in the manner of a plug as the closure plate 10 is inserted into the access opening 17 from above.

One appropriate material from which to manufacture the resilient elastomer is a Neoprene rubber, although other -suitable resilient elastomers could be used.

Where the frame of the cover and frame assembly with which the closure plate is used is of another configuration than rectangular, the outer configuration of the closure plate would need to be changed to correspond.

Further, the configuration of the side region of the closure plate could be modified as required.

It will be appreciated that the gasket 20 does not form a perfect seal with the mouth 5 of the flange 24 of the frame although the seal achieved using the gasket 20 is considerably improved compared with known constructions.

The features disclosed in the foregoing description or the accompanying drawings, expressed in- their specific forms or in terms of a means for performing the disclosed function, or a method or process for attaining the disclosed result, or a class or group of substances or compositions, as appropriate, may, separately or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

1. A cover and frame assembly of the kind specified including a closure plate co-operating with the frame to retain the closure plate within the access opening, the closure plate having formed around its periphery a resilient gasket.

2. An assembly according to claim I wherein the closure plate is of generally similar outer configuration to the configuration of the access opening, the gasket closing a space which would otherwise exist between the closure plate and a wall of the access opening.

3. An assembly according to claim 1 or claim 2 wherein the plate comprises a Glass Reinforced Plastics (GRP) material, which is resistant to -acidic fumes.

4. An assembly accordinq to claim 3 wherein the gasket is formed integrally with the plate by attaching the gasket to the plate during formation of the plate.

5. An assemhly according to claim 4 wherein the plate is moulded and the gasket positioned before the GRP has set (as herein defined).

6. An assembly according to claim 5 wherein the periphery of the GRP closure plate has first co-operating formations and the gasket has second cooperating formations, the first and second co-operating formations engaging as the gasket is positioned to provide added resistance to separation of the gasket from the plate.

7. An assembly according to any one of claims I to 4 wherein the gasket is retained in position by the engagement of first co-operating formations of the plate and second co-operating formations of the gasket, and/or the gasket is adhered in position with an adhesive.

8. An assembly according to any one of claims I to 7 wherein the frame of the assembly has a continuous flange which extends inwardly around the access open ng, the gasket, in use, co-operating with the flange.

9. An assembly according to claim 8 wherein the outer periphery of the gasket has an inclined surface which engages with the flange in the manner of a wedge as the closure plate is inserted in the access opening from above.

10. An assembly according to any one of the preceding claims wherein the gasket comprises a resilient elastomer.

II. An assembly substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

12. A method of securing a resilient elastomer to a member made of GRP material, comprising moulding the member and before the GRP material has set (as herein defined) positioning the resilient elastomer, and then allowing the GRP to set.

13. A method according to claim 12 wherein the GRP member is moulded with first co-operating formations which are engaged with second cooperating formations of the resilient elastomer to provide added resistance to separation of the GRP member and the resilient elastomer.

14. A method according to claim 12 or claim 13 when applied to a cover and frame assembly according to any one of claims 1 to 11 for securing the gasket to the periphery of the closure plate.

15. A method of securing a resilient elastomer to a member made of GRP material substantially as hereinbefore described with reference to the accompanying drawings.

I 6. Any novel feature or novel combination of features disclosed herein and/or shown in the accompanying drawings.