GB2280921A - Lockable unit for installation in a manhole cover - Google Patents

Abstract

A lockable unit for installation in a manhole cover comprises an annular housing (1), a cover (3) having locking means for engagement with the housing and a seal (12) of compressible elastomeric material interposed between the cover and the housing. <IMAGE>

Description

Fig. 2 is a cross-section taken along the line II II of Fig. 1; Fig. 3 is a plan view of the cover of the cover unit; Fig. 4 is an enlarged cross-section taken along the line IV-IV of Fig. 3.

Fig. 5 is a plan view of a second embodiment of a cover unit housing; Fig. 6 is a cross-section taken alng the line VI-VI of Fig. 5; Fig. 7 is a plan view of the cover of the cover unit; Fig. 8 is an enlarge cross-section taken along the line VIII-VIII of Fig. 7 and Fig. 9 is an exploded view of a manhole fitted with the cover unit shown in Figs. 5 to 8; Fig. 10 is a plan view of another embodiment of a cover housing; Fig. 11 is a side elevation of the cover housing of Fig. 10; Fig. 12 is a section taken along the section line 12-12 of Fig. 10; Fig. 13 is a plan view of a cover for the housing of Figs. 10 and 11; Fig. 14 is a side eievation of the cover shown in Fig. 13; Fig. 15 is a cross-section taken along the section line 15-15 of Fig. 13; and Fig. 16 is a fragmentary view of a handle and key for reieasing and removing the cover from the housing.

The cover unit is made of stainless steel and comprises an annular housing 1 with an inner opening measuring 200 mm diameter with a 900 stepped flange 2, 20 mm wide, in which a lid 3 (see Figs. 3 and 4) is supported. The upper surface of the housing 1 has a peripheral flange 4 20 mm wide, in which are trilled six 5 mm diameter holes 5 spaced radially around the flange 4.

The flange 4 has at least two keeps 6 located at opposite sides of the housing and secured to the flange, e.g., by spot welding.

The cover 3 is circular, measuring 238 mm in diameter, and has a central portion 7 dished below the cover surface with a flat strip 8 extending across the cover to form a handle 9. The strip is secured, e.g. by spot welding to the cover and extends from the outer periphery of the cover to form two projections 10 which, when the cover 3 is located in the housing recess, align with the keeps 6.

The cover 3 has a downwardly extending peripheral rim 11, 6 mm deep, around which is located a resilient gasket 12, measuring 20 mm wide x 10 mm thick, stuck with a contact adhesive. The gasket 12 is preferably made of an elastomeric material such as that soid under the Trade Mark NEOPRENE. The gasket can be readily replaced should it become worn or fail to provide a gas-tight seal between the cover 3 and housing 1.

In the second embodiment, like parts have the same reference numerals as in the first embodiment, the difference being in the method of securing the cover 3 to the housing 1. Instead of two projections 10 and two keeps 6 the cover has three projections 13 spaced at 1200 from each other around its periphery. These projections locate in slots 14 formed in the inner periphery of housing 1. The slots are formed by spot-welding rectangular plates 15 over rectangular apertures 16 in the upper surface of the housing 1.

The cover 3 has a handle 17 formed integral with the cover so that it iies flush with the surface. The central portion 7 of the cover is dished as in the first embodiment.

Fig. 9 shows an exploded view of an an existing steel manhole 18 and inspection cover 19 measuring 600 mm x 450 mm. A circular hole measuring 240 mm diameter is cut out of the cover and matching holes are then drilled to correspond with the holes 5 drilled in the housing and a line of silicone seaiant is applied to the manhole/insgection cover around the line of the drilled holes. The housing 1 is then secured to the manhole/inspection cover by boits, self-tapping screws or pop rivets (not shown) located in the holes 5 and the matching holes in the manhole/inspection cover.

To secure the cover 3 to the cover unit housing 1 the projections 13 are located in the rectangular apertures 16 and rotated in a clockwise direction so that the projections 13 locate under the welded plates 15. The gasket 12 is compressed and forms a hermetic seal between the cover 3 and housing 1.

In a third embodiment illustrated in Figs. 10 to 15, like parts have the same reference numerals as in the two previous embodiments. The cover unit comprises an annular housing 1 closed by a removable cover 3, the housing having a stepped annular rim 20 as shown by the cross-section 12-12 (see Fig. 12). The outer rim 4 has six holes 5 by means of which the cover unit is securea to a manhole/inspection cover as hereinbefore decribed.

The stepped flange 2 has three keyhole shaped apertures 21 which pass through the annular housing.

The circular hole formed by the housing 1 is closed by the circular cover 3 iliustrated in Figs. 13 to 15.

Spaced at 120 about the periphery of the cover are downward projections 22 with enlarged heaas 23. These projections align with the keyhole apertures 21 on the housing and, on rotation of the cover relative to the housing, the enlarged heads 23 lock under the narrow parts of the keyhole apertures to secure the cover 3 to the housing 1.

An hermetic seal is formed between the cover and flange of the housing by an elastomeric gasket 12 stuck to the underside periphery of the cover 3. A suitabie elastomeric material is that sold under the Trade Mark NEOPRENE.

The centre of the cover 3 has a circular plate 24 formed with a hole 25 which extends at opposite sides thereof into slots 26. The plate is welded into a dished part 27 of the cover which seals the hole 25 and slots 26 from the underside of the cover. The dished part 27 forms a space below the plate 24 to accommodate a key 28, illustrated in Fig. 16.

The key 28 comprises a shaft 29 with a handle 30 at its upper end. The lower end has a flat plate 31 which is shaped to be located in the hole and slots in the plate 24 so that by rotating the key anti-clockwise the cover 3 is rotated to remove the projections 22 from the slots of the apertures 21. A pin 32 is welded to the key shaft 29 and spaced from the plate 31 a distance equal to the thickness of the plate 24 so that, by iowering the key and rotating it, the cover can be heid between the key plate 31 and pin 32 to lift and remove it from its housing.

The length of the key shaft is chosen so that the key can be manipulated by a person in a standing position avoiding the need to stoop or kneel. The key does not come into contact with the underside of the cover or housing so that there is no risk of it contacting the contents being disposed of.

The cover 3 is attached to the underside of the housing 1 by a chain (not shown) to prevent loss of the cover).

The -cover unit is made of stainless steel to allow for frequent hosing-down without corrosion and is designed without recesses or grooves on its surface which may trap dirt and make cleaning difficult.

Various modifications may be made to the cover unit described. For example, a greater number of projections than three may be provided on the cover to engage a corresponding number of recesses or keeps in the housing to provide an evenly distributed locking effect between the cover and housing.

In an alternative embodiment, the underside of the cover may have a linkage connected to the projections which is operated by a handle hinged in a recess on the cover surface so that, by lifting the handle and turning it a quarter of a turn through 900, the linkage extends the projections beyond the periphery of the cover to engage the underside of the stepped flange of the housing.

An instruction plate is fitted to the upper surface of the cover to indicate the rotational direction of the cover to 'lock' and 'unlock' it. The plate may aiso include a warning against depositing harmful material, such as stones, in the manhole.

It will be obvious that manhole/inspection covers may be manufactured incorporating the cover unit according to the invention for installation in new sewage systems.

CLAIMS: 1. An animal waste disposal cover unit comprising an annular housing of stainless steel for installation in an aperture in a domestic manhole/inspection cover of a sewage system, and a cover of stainless steel having two or more locking means adapted to be locked to the annular housing by engaging the locking means of the cover with locking means of the housing, wherein a gas-tight seal of compressible elastomeric material is interposed between the cover and surrounding housing.

2. An animal waste disposal cover unit as claimed in Claim 1, wherein the locking means comprises three projections, having enlargements at their free ends, on the cover which locate in keyhole shaped apertures in the annular housing.

3. An animal waste disposal cover unit as claimed in Claim 1 or 2, wherein the centre of the cover has a hole with a slot on opposite sides of the hole with a dished cover sealing the hole and slots from the underside of the cover.

4. An animal waste disposal cover unit as claimed in Claim 3, wherein an elongated handle is provided comprising a shaft with an end plate to fit the hole and slots on the cover and a pin spaced along the shaft from the end plate a distance equal to the thickness of the cover.

5. An animal waste disposal cover unit as claimed in Claim 1, wherein the locking means comprises two projections spaced peripherally at opposite sides of the cover to engage correspondingly spaced keeps on the housing.

6. An animal waste disposal cover unit as claimed in Claim 1, wherein the locking means comprises three projections spaced at 1200 around the cover's periphery, which projections engage correspondingly spaced slots formed in the surrounding housing.

7. An animal waste disposal cover unit as claimed n any of Claims 1, 5 or 6, wherein the cover is dished at its centre and has a handle flush with its peripheral surface.

8. An animal waste disposal cover unit as claimed in Claim 7, wherein the handle is pivotable and operates a linkage to extend and retract the projections from the periphery of the lid to engage the underside of the housing to lock and unlock the cover unit.

9. A manhole/inspection cover fitted with an animal waste disposal cover unit as claimed in any preceding ciaim.

10. An animal waste disposal unit substantially as herein described with reference to and as shown in Figs.

i to 4, Figs. 5 to 8 or Figs. 10 to 16 of the accompanying drawings.

11. A manhole/inspection cover fitted with an animal waste disposal unit, substantially as herein described wit reference to Fig. 9 of the accompanying drawings.

Claims (1)

1. Patents Act 1977 Application number

   Examiner's report to the Comptroller under Section 17 GB 9416077.7 (The Search report) -10- Relevant Technical Fields Search Examiner MR MR D HAWORTH (i) UK Cl (Ed.M) E1G (G96B) (ii) Int Cl (Ed.S) E02D 29/14 Date of completion of Search 1 NOVEMBER 1994 Databases (see below) Documents considered relevant (i) UK Patent Office collections of GB, EP, WO and US patent following a search in respect of specifications. Claims 1 1-11 (ii) ONLINE DATABASE: WPI Categories of documents X Document indicating lack of novelty or of inventive step.

   Y: Document indicating lack of inventive step if combined with one or more other documents of the same category.

   A: Document indicating technological background and/or state of the art.

   P: Document published on or after the declared priority date but before the filing date of the present application.

   E. Patent document published on or afler, but with priority date earlier than, the filing date of the present application.

   & Member of the same patent family; corresponding document.

   Category Identity of document and relevant passages Relevant to claim(s) A I GB 2247037 A (MCGREGOR) A I GB 0297006 A (BRENT) Databases: The UK Patent Office database comprises classified collections of GB, EP, WO and US patent specifications as outlined periodically in the Official Journal (Patents). The on-line databases considered for search are also listed periodically in the Official Journal (Patents).