GB2374373A

GB2374373A - Cover for ground surface access assembly

Info

Publication number: GB2374373A
Application number: GB0109187A
Authority: GB
Inventors: Barry Turner
Original assignee: Wrekin Welding and Fabrication Engineering Ltd
Current assignee: Wrekin Welding and Fabrication Engineering Ltd
Priority date: 2001-04-12
Filing date: 2001-04-12
Publication date: 2002-10-16
Anticipated expiration: 2021-04-12
Also published as: GB0109187D0; GB2374373B

Abstract

The cover, particularly for use with manholes, gully gratings etc., includes a pocket 21 for receiving a part of a key 28 for lifting the cover and an opening 26 for allowing the part of the key access to the pocket, the pocket being alterable between a closed condition in which the base of the pocket remote from the opening is closed and a released condition in which the base of the pocket is open. Preferably the pocket is completely closed except for the key opening when in the closed condition and includes an enclosure member 40 is movable from a closed to an open position so as to alter the condition of the pocket. The enclosure member preferably forms the base 42 of the pocket and may additionally include one or more side walls, with the enclosure member being moved from the closed to the open position by pressure from the key being inserted into the pocket. The movable part of the enclosure member is preferably retained in the closed position, until pushed to the open position, by e.g. flexible lips 44 on the base member which engage the wall of the enclosure member and the movable portion is preferably either rotatably secured to enclosure member at one side or is attached to the enclosure member by a flexible element 46 so that it remains attached when in the open position.

Description

Ground Surface Access Assemblies The invention relates to ground surface access assemblies such as manhole assemblies and gully gratings. Such assemblies allow access to sewers, water hydrants and other below surface installations, via openings in the roads, pavements, etc. , above.

A ground surface access assembly typically includes a generally rectangular frame and a cover mountable on the frame. The cover can be lifted from the frame to gain access to the below surface installation. Conventionally, a cover includes keyways in the form of openings in which keys may be inserted to engage the cover and lift it clear of the frame. A closed pocket is generally provided below each opening, a part of the key being received within the pocket when the key is used to lift the cover.

A problem with the above prior art arrangements is that dirt and debris tend to accumulate within the keyway pockets. This may take a considerable time to clean in order to allow the lifting key to be introduced into the pocket.

According to the invention there is provided a cover for a ground surface access assembly, the cover including a pocket for receiving a part of a key for lifting the cover and an opening for allowing the part of the key access to the pocket, the pocket being alterable between a closed condition in which a base of the pocket remote from the opening is closed and released condition in which the base of the pocket is open.

Preferably in the closed condition, the pocket is substantially completely closed, except for the opening for the key.

Preferably the pocket includes an enclosure member defining an orifice within the enclosure member.

Preferably at least a part of the enclosure member is moveable between a

closed and an open position, to alter the condition of the pocket.

Preferably the enclosure member includes one or more side walls extending downwardly in use from the cover and a base extending between the side walls. The enclosure member may include a generally cylindrical side wall and may include a generally circular base.

The moveable part of the enclosure member may comprise the base.

Alternatively, the moveable part may comprise the base and all or a part of the side walls.

Preferably the moveable part may be moved from the closed to the open position by pressure of a key inserted into the pocket. The moveable part may be so moved by hand pressure on the key. Alternatively the moveable part may be moved by an impact blow to the top of the key. Preferably the moveable part may be so moved when the cover member is in use, mounted on the frame of the access assembly.

The cover may include means for retaining the moveable part in the closed position until it is pushed out of that position by the key. The retaining means may be provided by friction between the moveable part and the remainder of the cover.

The moveable part may include a base member, which may be substantially planar, and one or more flexible lips extending transversely to the base member at a perimeter thereof. The lips may be substantially perpendicular to the base member. A flexible lip may extend continuously around the perimeter of the base member. Alternatively a plurality of lips may extend intermittently around the perimeter of the base member. When the moveable part is in the closed position, the flexible lip or lips may embrace a wall of the enclosure member. Alternatively the or each lip may include detent protrusions extending outwardly therefrom and the lip may be insertable within the wall or walls of the enclosure member when the moveable part is in its closed position, the detent protrusions retaining the lip in place. The lip or lips

are preferably made of a plastics material. The moveable part may be made of a plastics material.

The moveable part may include a base member, which may be substantially planar, rotatably attached to a wall of the enclosure member at one side thereof. An opposite side of the moveable part may be provided with a flexible member protruding from the base member, the flexible member embracing or engaging a wall of the enclosure member to retain the moveable part in the closed position. The rotatable attachment may comprise a generally cylindrical member provided on the moveable part, the cylindrical member being received within a complementary recess provided in the wall of the pocket.

Preferably the moveable part is attached to the reminder of the cover even when in the open position. The moveable part may be attached to a side wall of the enclosure member. The attachment means may include a flexible member extending between the moveable part and the remainder of the cover.

The cover is preferably adapted to receive a key including an elongate shank and a foot extending transversely to the shank. The foot may be provided at an end of the shank. Preferably the key further includes a transversely extending head towards its other end. The key may be rotatable between a first orientation in which it is able to pass through the opening to enter or leave the pocket and a second orientation in which it cannot pass through the opening. Means may be provided for preventing the key from returning to the first orientation while it is being used to lift the cover.

The invention further provides a cover and key arrangement for a ground surface access assembly, the arrangement comprising a cover and a key as defined in any of the preceding paragraphs.

The invention further provides a ground surface access assembly including a cover according to any of the preceding definitions.

An embodiment of the present invention will be described for the purpose of illustration only with reference to the accompanying drawings, in which: Fig. 1 is a diagrammatic plan view of a conventional manhole assembly including a frame and a cover member ; Fig. 2 is a diagrammatic plan view of a cover member split into its triangular parts; Fig. 3 is a diagrammatic sectional view showing lifting keys inserted into keyways during lifting of a cover; Figs. 4A to 4D illustrate the use of a keyway to lift a conventional manhole cover; Figs. SA to 5E illustrate the use of a key to lift a manhole cover according to the invention; Figs. 6A to 6E are similar views to those of Figs. 5A to SE, but illustrating an alternative embodiment of the invention; Figs. 7A to 7E are similar views to those of Figs. SA to SE, but illustrating an alternative embodiment of the invention; and Fig. 8 is a diagrammatic representation of a lifting key.

Referring to Figs. 1 and 2 of the drawings, a manhole assembly 10 includes a frame 12 and a cover member 14. The cover member 14 is formed of cast metal and comprises two substantially planar triangular cover parts 16 provided with triangular projections 18 on their upper surfaces. These projections 18 allow traffic to pass over the manhole assembly 10 without skidding by providing a high friction surface.

As shown in Fig. 2, the two triangular parts 16 of the cover member 14 are"loose-linked"together in use by a nut and bolt arrangement 20. The use of two triangular cover parts 16 loosely linked together rather than a single rectangular part 16 allows each cover part to be stably supported at three corners, on seats provided on the frame 12.

To allow access to the manhole chamber, it is necessary that the cover parts 16 are removable from the frame 12. Keyways 22 are thus provided on each part 16 of the cover member 14 allowing a key 24 (see Fig. 3) to be inserted to lift the cover part 16, as described below. The keyways 22 are each near the centre of gravity of the respective cover part 16. This reduces the chance of the cover member 14 tilting while it is being lifted.

Referring to Fig. 8, a lifting key 24 includes an elongate shank 25 provided with a transversely extending foot 28 at its end. At an opposite end of the shank 25, the key 24 includes a generally oval head 29, manipulation of which allows the key 24 to be rotated or lifted.

Figs. 4A to 4D show a conventional keyway 22 into which the lifting key 24 can be inserted. The keyway 22 consists of a pocket 21 for receiving the foot 28 of the key 24. The boundaries of the pocket are defined by an enclosure member, comprising side and base walls 31 and 33 respectively, and by a top wall 35. The top wall 35 includes an opening 26. The opening 26 is shaped such that it has a generally circular centre portion and two transversely extending arms. The opening is thus a similar shape to a base of the key 24 and is sized such that the foot 28 of the key can pass through the opening 26 when the key 24 is correctly aligned.

Once the foot 28 of the key 24 is in the keyway 22, the key 24 may be rotated through an angle of about 900. This brings the foot 28 of the key 24 into contact with an undersurface 30 of the top wall 35 of the keyway 22. The key 24 may then be used to lift the cover part 16 off the frame 12, the key being held in place by the weight of the cover part 16 pressing against the key foot 28.

The two cover parts 16 may be lifted together to remove the cover member 14 from the frame 12.

As illustrated in Figs. 4C and 4D, there is a tendency for the pocket 21 to become filled with dirt and debris. When this happens, it is impossible to insert the lifting key 24 into the pocket 21 to lift the cover part 16 (see Fig. 4D). Thus, before the cover member 14 can be removed from the frame 12, the dirt must be removed from the pocket 21. This can be difficult and time consuming.

Referring to Figs. 5A to 5E, there is illustrated a keyway 22 according to a first embodiment of the invention. The keyway 22 is of a generally similar shape to the prior art keyway except that the base wall 31 is replaced with a moveable part in the form of a closure 40. The closure 40 includes a generally planar, circular base 42 and a lip 44 extending upwardly in use out of the plane of the base 42, perpendicularly thereto. The closure is made of a flexible plastics material. A flexible cord 46 links the closure 40 with a retention member 48 which is retained within the pocket 21. The flexible cord 46 passes through a hole 47 in the side wall 31 of the keyway 22.

The lip 44 of the closure 40 is generally cylindrical but is provided with outwardly extending detent protrusions 50 on its radially outer surface. The closure 40 may be moved into the position illustrated in Figs. SA and 5B, where the lip 44 is inside and in contact with an inner surface 52 of the side wall 31 of the pocket 21. In such closed position, the protrusions 50 on the lip 44 provide resistance against downward movement of the closure 40. However, if sufficient downward force is applied to the base 42 of the closure 40, this overcomes the friction between the lip 44 and the inner surface 52 of the wall 31 and allows the closure 40 to move into the open position illustrated in Fig.

5C.

The keyway 22 according to the invention works as follows. In normal use, the closure 40 is left in the closed position of Fig. 5A. In this position, the flexible lip 44 acts to retain the closure 40 in position functioning as a base of

the pocket 21.

Over time, dirt and debris tend to pass through the opening 26 of the keyway 22 into the pocket 21. This debris is illustrated in Fig. 5A. When an operator wishes to lift the cover member 14, the lifting key 24 may be manipulated so as to pass its foot 28 through the opening 26 into the pocket 21.

It meets a resistance in the form of the dirt which has built up in the pocket 21 but, if the operator continues to push the key 24 in the downward direction, eventually the frictional engagement between the lip 44 and the inner surface 52 of the pocket wall 31 is overcome and the closure 40 moves into the open position illustrated in Fig. 5C. This allows the debris to fall out of the bottom of the pocket 21 and enables the key easily to enter the pocket. The key may then be lifted and rotated into the position shown in Fig. 5D and used to lift the respective cover part 16 of a cover member 14.

In the open position, the closure 40 is still attached to the wall 31 of the pocket 21 by the flexible cord 46 and the retention member 48. The closure 40 may be repositioned in the closed position, as indicated in Fig. 5E, before the cover member 14 is placed back on the frame 12.

Fig. 6A to 6E illustrate an alternative embodiment of the invention. In this embodiment, the closure 40 is generally similar to that of the Figs. SA to 5E embodiment, but has a somewhat larger circular base 42. A lip 44 extends upwardly from a perimeter of the base 42 and is provided with a single detent protrusion 50 at its top edge. The lip 44 is able to embrace the generally spherical wall 31 of the keyway 22 and grip the wall 31 to keep the closure 40 in place. The lip is made of a resilient plastics material.

The embodiment of Figs. 6A to 6E works in the equivalent manner to the Fig. 5 embodiment.

Referring to Figs. 7A to 7E, there is illustrated a further alternative embodiment of the invention. In this embodiment, the closure 40 is made of

cast metal and includes a generally planar part in the form a circular base 42. Extending upwardly in use from one edge of the base 42 is a cylindrical mounting member 54 which is received within a complementary recess 56 in the wall 31. The closure 40 is thus pivotally mounted so as to be able to rotate about a centre point of the cylindrical member. An opposite side of the base 42 is provided with an upwardly extending flexible tang 58 which is able to form an interference fit against an outer cylindrical surface 60 of the wall 31. The engagement of the tang 60 with the wall 31 retains the closure 40 in the closed position illustrated in Figs. 7A and 7B. However, the closure 40 may pivot into the open position illustrated in Fig. 7C when pushed in the downward direction by the lifting key 24, in a similar manner to that described for the previous embodiments.

There is thus provided a cover for a ground surface access assembly, the cover including keyways which overcome the problems of the prior art.

Various modifications may be made to the above described embodiments without departing from the scope of the invention. Alternative means for attaching the closure 40 to the remainder of the cover part 16 may be provided and the attachment to the cover part need not be on the wall 31. Instead of only a base part of the pocket 21 forming the closure 40, the whole pocket, including side and base walls, may be moveable to allow the release of dirt from the pocket. The generally cylindrical lip 44 may be replaced with a plurality of resilient members which together embrace the wall 31.

Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. A cover for a ground surface access assembly, the cover including a pocket for receiving a part of a key for lifting the cover and an opening for allowing the part of the key access to the pocket, the pocket being alterable between a closed condition in which a base of the pocket remote from the opening is closed and released condition in which the base of the pocket is open.

2. A cover according to claim 1, wherein in a closed condition, the pocket is substantially completely closed, except for the opening for the key.

3. A cover according to claim 1 or claim 2, wherein the pocket includes an enclosure member defining an orifice and wherein, at least a part of the enclosure member is moveable between a closed and an open position, to alter the condition of the pocket.

4. A cover according to claim 3, wherein the enclosure member includes one or more side walls extending downwardly in use from the cover and a base extending between the side walls.

5. A cover according to claim 4, wherein the enclosure member includes a generally cylindrical side wall and a generally circular base.

6. A cover according to claim 5, wherein the moveable part of the enclosure member comprises the base.

7. A cover according to any of claims 3 to 6, wherein the moveable part may be moved from the closed to the open position by pressure of a key inserted into the pocket.

8. A cover according to claim 7, wherein the moveable part may be so moved when the cover member is in use, mounted on the frame of the access assembly.

9. A cover according to any of claims 3 to 8, wherein the cover includes means for retaining the moveable part in the closed position until it is pushed out of that position by the key.

10. A cover according to any of claims 3 to 9, wherein the moveable part includes a base member, which may be substantially planar, and one or more flexible lips extending transversely to the base member at a perimeter thereof.

11. A cover according to claim 10, wherein when the moveable part is in the closed position, the flexible lip or lips embrace a wall of the enclosure member.

12. A cover according to claim 10, wherein the or each lip includes detent protrusions extending outwardly therefrom and wherein the lip is insertable within the wall or walls of the enclosure member when the moveable part is in its closed position, the detent protrusions retaining the lip in place.

13. A cover according to any of claims 3 to 9, wherein the moveable part includes a base member, which may be substantially planar, rotatably attached to a wall of the enclosure member at one side thereof.

14. A cover according to claim 13, wherein an opposite side of the moveable part is provided with a flexible member protruding from the base member, the flexible member embracing or engaging a wall of the enclosure member to retain the moveable part in the closed position.

15. A cover according to any of claims 3 to 14, wherein the moveable part is attached to the remainder of the cover even when in the open position.

16. A cover according to claim 15, wherein the attachment means includes a flexible member extending between the moveable part and the remainder of the cover.

17. A cover according to any preceding claim, wherein the cover is adapted to receive a key including an elongate shank and a foot extending transversely to the shank.

18. A cover and key arrangement for a ground surface access assembly, the arrangement comprising a key and a cover according to any preceding claim.

19. A ground surface access assembly including a cover according to any of claims 1 to 17.

20. A cover for a ground surface access assembly, the cover being substantially as herein described with reference to the drawings.

21. Any novel subject matter or combination including novel subject matter disclosed herein, whether or not within the scope of or relating to the same invention as any of the preceding claims.