GB2264528A

GB2264528A - Fastening and key for closure assemblies such as manhole covers.

Info

Publication number: GB2264528A
Application number: GB9204140A
Authority: GB
Inventors: David Haydn Williams; Richard Owen Burton
Original assignee: Frederick Jones & Son
Current assignee: Frederick Jones & Son
Priority date: 1992-02-27
Filing date: 1992-02-27
Publication date: 1993-09-01
Anticipated expiration: 2012-02-27
Also published as: GB9204140D0; GB2264528B

Abstract

The present specification discloses a closure assembly comprising a closure member (1) and a frame (3) (eg a manhole and its cover) with a locking mechanism (5) being arranged to securely lock the closure member (1) to the frame (3). The locking mechanism (5) comprises at least one pivotal locking member (15) which is spring biassed to a position wherein it can engage the frame (3) to securely lock the closure member (1) to the frame (3). The locking mechanism (5) is operable by a key (31) which, when inserted into the locking mechanism (5), is rotatable to pivot the or each locking member (15) against the spring bias towards a release position in which the key (31) is retainable by a spring loaded part (45) of the key (31), said spring loaded part (45) then engaging a shoulder or recess (47) in the closure member (1). <IMAGE>

Description

DESCRIPTION IMPROVEMENTS RELATING TO CLOSURE ASSEMBLIES INCORPORATING A LOCKING MECHANISM The present invention relates to a closure assembly incorporating a locking mechanism.

In particular the present invention relates to a closure assembly in the form of an access or manhole cover, grating or such like, which can be engaged on a frame which defines an opening, the locking mechanism being operable to securely lock the cover to the frame so as to prevent unauthorised access.

The aim of the present invention is to provide a closure assembly incorporating a locking mechanism which requires a key of complementary configuration, said key being retainable in the lock open position whereby the key can be used to open the closure assembly.

According to the present invention there is provided a closure assembly comprising a closure member and a frame, the frame defining an access opening which the closure member can close, a locking mechanism being arranged to securely lock the closure member to the frame, the locking mechanism comprising at least one pivotal locking member which is spring biased to a position wherein it can engage the frame to securely lock the closure member to the frame, the locking mechanism being operable by a key which when inserted into the locking mechanism is rotatable to pivot the or each locking member against the spring bias towards a release position in which the key is retainable by a spring loaded part of the key, said spring loaded part then engaging a shoulder in the closure member.

In a preferred embodiment of the present invention the frame incorporates a locking gate with a number of parallel gate projections which project inwardly of the frame, a number of locking members being engageable therewith. With the closure member, e.g. access cover, located on the frame and securely locked thereto, the locking members each are spring biased to a position beneath a gate projection.

Preferably, there are three gate projections and three pivotal locking members. If however desired, there may be more than three gate projections and locking members. Each locking member preferably comprises a barrel or disc portion and a radially outwardly projecting prong which engages under a gate projection in the locked position. The barrel or disc portion has a centrally located aperture which is specifically shaped to provide a shoulder against which part of the key can engage to enable the locking member to be rotated by the key towards the released position.

The apertures in the barrel portions of the respective locking members have shoulders which are at different angles, these shoulder angles being matched to the relative positions of laterally projecting projections provided along the length of the key so that with the key inserted the projections can each engage a matched shoulder whereby the locking members are rotated towards the released position in unison.

Thus a specific key is required for a particular lock.

The key preferably has an elongate shaft portion and a handle portion, the lateral projections being suitably positioned along the length of the elongate shaft portion at the required angles to mate with the said shoulders of the locking members. The handle portion preferably has a spring loaded part in the form of a peg which projects generally parallel to but spaced laterally from, the elongate shaft, the spring loaded peg engaging behind a shoulder i.e. engaging in a recess in the outside surface of the closure member, when the key has attained the released position. Thus the key and locking members are retained in the released position by the spring loaded peg and the handle portion of the key can be used to lift the access cover off the frame.The spring loaded peg may be released either by a positive manual retraction of the peg, or the tip of the peg and the recess may be rounded or tapered so that rotational pressure on the key in the locking direction will cause the peg to retract against its spring loading, the locking members being then moved to the locked position by both the key and their spring bias.

The present invention will- now be further described, by way of example, with reference to the accompanying drawings, in which: Fig.1 is a partial cross-sectional view of part of a preferred embodiment of the present invention; Fig.2 is a cross-sectional view along line A-A in Fig.1; Fig.3 is a cross-sectional view along line B-B in Fig.1; Fig.4 is a plan view of the locking mechanism used in Figs. 1 to 3; and Fig.5 shows the key used in the locking mechanism of Figs. 1 to 4.

The preferred embodiment of the present invention, illustrated in the accompanying drawings, comprises a closure member in the form of an access cover 1 which is supported on a frame 3 and securely locked thereto by a locking mechanism generally designated 5. The access cover 1 and the frame 3 are rectangular with the access cover 1 having a depending edge 7 which locates in a groove 9 formed on the inside edge of the frame 3. Alternatively the cover and frame may be of any desired shape or configuration.

The locking mechanism 5 comprises a barrel housing 11 which is secured to the underside of the access cover 1 by bolts 13. Three locking members 15 are located in the barrel housing 11, each locking member 15 comprising a disc portion 17, the respective disc portions being coaxially aligned with each other and having respective radially outwardly extending prongs 19, which prongs 19 extend through slots in the wall of the barrel housing 11 and, in the illustrated locked position, engage a gate 21 forming part of the frame 3. As seen in Figs. 1, 2 and 3 the gate 21 has three parallel gate projections 23 and in the illustrated locked position a prong 19 engages under a corresponding gate projection 23. Springs 25 extend between the prongs 19 and the housing 11, and bias the locking members 15 to the illustrated locked position and thus maintain the access cover 1 locked to the frame 3.In alternative embodiments (not illustrated) more than three or less than three locking members and gate projections can be provided.

Each disc portion 17 has a centrally located aperture 27 shaped to provide a shoulder 29, the shoulders 29 of two of the respective disc portions 17 being at different angles relative to each other. The locking mechanism is releasable by a key 31 (see Figs.

1 and 5), the key having an elongate shaft portion 33 and a handle portion 35. Lateral projections 37,39,41 project in oppositely directed pairs from spaced apart locations along the length of the elongate shaft portion 33. The projections 37 and 41 are parallel to each other and the centrally located projections 39 are at right angles thereto. As the key 31 is inserted in the locking mechanism 5 through keyhole 43 (see Fig.4) the key is rotated through 900 when projections 41 have passed through the aperture in the uppermost disc portion 17 to allow the centrally located projections 39 to pass through the keyhole 43 and the uppermost disc portion 17. The key 31 is then rotated again through 900 to allow the entry of the projections 37. With the key 31 fully inserted, the key 31 can be rotated, the projections 37,39 and 41 simultaneously engaging the respective shoulders 29 so that the locking members 15 are rotated in unison out from underneath the respective gate projections 23 against the bias of springs 25. Whilst the illustrated embodiment utilises a key 31 with adjacent sets of lateral projections set at right angles to each other, the lateral projections 37,39 and 41 of key 31, and the associated shoulders 29, can be arranged at any desired workable relative angles, i.e.

at inclusive angles different from 900, the only essential factor being that the lateral projections all simultaneously engage an associated shoulder 29 to move the locking members 15 in unison.

When the locking members 15 have been rotated clear of the respective gate projections, a spring loaded part in the form of a peg 45 provided on the handle portion 35 of the key 31 and extending generally parallel to the elongate shaft portion 33 of the key 31, engages into a recess 47 in the outer surface of the access cover 1 to thus lock the locking mechanism 5 in the released condition. The handle portion 35 of the key 31 can then be used to lift the access cover 1 off of the frame 1. Clearly two or more locking mechanisms 5 can be provided to both increase the security of the installation, it being possible for like or different keys to be necessary, and to facilitate lifting of the access cover 1.

As evident in Figs. 1 and 2, the peg 45 has a tapered end region which enables the peg to be retracted solely by applying sufficient rotational force to the key 31 so that the edge of the recess 47 acts on the tapered end region to move the peg 45 against its spring loading. Alternatively the peg 45 can be manually retractable to release the key 31, the springs 25 returning the locking members to the locked position.

The present invention thus provides a closure assembly whereby the locking mechanism incorporated therein can provide a high degree of access security whilst also facilitating opening, i.e. lifting, of the closure member, when the locking mechanism is moved to a released condition.

Claims

1. A closure assembly comprising a closure member and a frame, the frame defining an access opening which the closure member can close, a locking mechanism being arranged to securely lock the closure member to the frame, the locking mechanism comprising at least one pivotal locking member which is spring biassed to a position wherein it can engage the frame to securely lock the closure member to the frame, the locking mechanism being operable by a key which, when inserted into the locking mechanism, is rotatable to pivot the or each locking member against the spring bias towards a release position in which the key is retainable by a spring loaded part of the key, said spring loaded part then engaging a shoulder in the closure member.

2. An assembly as claimed in claim 1, in which the frame incorporates a locking gate with a number of parallel gate projections which project inwardly of the frame, a number of locking members being engageable therewith.

3. An assembly as claimed in claim 2, in which with the closure member located on the frame and securely locked thereto, the locking members are each spring biassed to a position beneath a gate projection.

4. An assembly as claimed in any one of claims 1 to 3, in which the or each locking member comprises a disc portion with a radially outwardly directed prong which engages the frame in the locked position.

5. An assembly as claimed in claim 4, in which the disc portion of the or each locking member has a centrally located aperture which is shaped to provide a shoulder against which part of the key can engage to enable the locking member to be rotated by the key away from the locked position.

6. An assembly as claimed in claim 5, in which at least two locking members are arranged in a housing with their disc portions coaxially arranged with respect to each other, and their respective radially outwardly directed prongs aligned with each other and projecting out of the housing, the shoulders in the respective central apertures being in different angular positions which match the relative angular positions of lateral projections provided along the length of the key.

7. An assembly as claimed in any one of the preceding claims, in which the key has a spring loaded part in the form of a spring loaded key which engages in a recess in the outside surface of the closure member when the key has been rotated to a released position for the locking mechanism.

8. An assembly as claimed in claim 7, in which the key has an elongate shaft portion and a handle portion, the spring loaded key projecting from the handle portion generally parallel to but spaced laterally from the elongate shaft.

9. An assembly as claimed in claim 8, in which the spring loaded key is manually retractable or retractable by manual rotation of the key towards the locked position.

10. A closure assembly constructed and arranged substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.