GB2191233A - Lockable access cover - Google Patents

Abstract

An access cover (10) for providing access to inspection chambers and/or access points to underground services, such as pipes and the like, or to an inspection chamber, is provided with a movable latching element (23) adapted to engage with an associated frame (11) so as to secure the cover (10) to the frame (11), the cover (10) being provided with a passageway (13) providing access to release means for moving the latching element (23) out of engagement with the frame (11) by a first release member (40) and wherein the passageway (13) is closed or otherwise obstructed by a closure member (28) to prevent access to the release means by the first release member (40), the closure member (28) being removable or releasable only by a second release member. <IMAGE>

Description

SPECIFICATION A new or improved access cover The present invention is concerned with access covers intended for providing access to inspection chambers and/or access points to underground services, such as pipes and the like, and is primarily concerned with the type of access cover for use with a frame which is normally secured in the ground or to an inspection chamber, the access cover closing the frame.

It is fairly frequent that such access covers are used where unauthorised access is undesirable, for example removal of such a cover may give access to a potentially dangerous environment, such as high voltage cables and it is desirable to provide some means of preventing unauthorised access thereto.

Such access covers could be provided with a conventional lock and key. However, because of the normal positioning of the access covers in roadways, pavements, floors of industrial buildings etc., such a provision is not practical since dirt and other foreign matter would soon render the lock useless and probably prevent access even to authorised key holders, since the lock, through the ingress of dirt, would soon cease to function.

It is known to provide access covers with a substantial latching element operable by a special release member and such access covers do provide a limited amount of security in deterring the casual intruder.

It is an object of the present invention to provide a new or improved access cover that provides increased security and is also reliable in operation.

According to one aspect of the present invention, we provide an access cover provided with a movable latching element adapted to engage with or be moved out of engagement with an associated frame so as to secure the cover to said frame, said access cover being provided with a passageway providing access to release means for said latching element by a first release member and wherein said passageway is closed or otherwise obstructed by a closure member to prevent access to said release means by said first release member, said closure member being removable or releasable only by a second release member.

Preferably, said second release member is spaced from the upper surface of said access cover and conveniently means may be provided to prevent sight of or instant access to said closure member.

The provision of the closure member not only provides a second deterrent to unauthorised access through the access cover, but also hides from view access to the release means for the latching element. Since sight of the release means is hidden, it enables the first release member to be of relatively simple form rather than an intricate key thus ensuring reliable operation.

Furthermore, the closure member prevents ingress of dirt or other foreign matter which may adversely affect the operation of the release mechanism of the latching element.

Preferably, the closure member is removed from said passage in an upwards direction so that any dirt or foreign matter having accumulated thereon is first removed from the access cover, or at least the passageway thereof, which further minimises the danger of failure of the latching element or its operating mechanism through the ingress of dirt.

Further security can be provided in the passageway providing access to the release mechanism and latching element by providing a passageway of a particular section, at least in part, to provide access only to a first release member of co-operating configuration.

The closure member may comprise an externally threaded member which co-operates with a thread formed on the passageway or a part thereof, said closure member having a specially formed head part enabling engagement only via the second release member which is of a special form to co-operate with said head.

Conveniently, said closure member may be provided with a "friction washer" or a friction compound may be provided on some or all of the threads thereof so that it may only be removed on application of a reasonable torque, thereby preventing or minimising removal by a person not equipped with said second release member.

It is further envisaged that said closure member may not only prevent access to the passageway provided for access to the release mechanism of the latching member but said closure member may also co-operate with said latching element or the release means therefor in a manner such that any unauthorised movement of said closure member will prevent operation of the latching member.

One example of the present invention will now be described in detail, by way of example only, with reference to the accompanying drawings, wherein: Figure 1 is a sectional view through an access cover constructed in accordance with the present invention; Figure 2 is a schematic view showing the latching element in a latching position and in broken outline in a release position; Figure 3 is a plan view of the head of the closure member; Figure 4 is a view of a first release member.

Referring first to Fig. 1, an access cover is generally indicated at 10 and may be made from any suitable material, for example steel, cast iron, stainless steel or a combination of such materials and in some installations may be made from a combination of plastics and metallic materials.

The access cover 10 closes a frame-like surround, part of which is generally indicated at 11. The cover 10 is formed with or has secured thereto a tube-like member 12 providing a passageway 13. The tube-like member 12 if secured to the access cover 10, will be secured in a manner where it is not movable relative thereto.

The tube-like member 12 carries at its lower end 14 a pair of plate members 15a, 15b, one of which is shown in Fig. 1 at 15a, and the other 15b is secured to the tube-like member 12 diametrically opposite so as to form a channel.

A sleeve-like member 16 is positioned around said tube-like member 12 and is of a dimension whereby at least limited rotational movement about the longitudinal axes of the tube-like member 12 and sleeve 16 are possible, the sleeve 16 being maintained in position on the tube-like member 12 by the provision of a plate-like member 16 secured thereto or formed integrally therewith which bears, preferably through a bearing member (not shown), on the upper surfaces of the pair of plates, one of which is shown at 15, secured to the tube-like member 12.

The plate-like member 16 has two spaced apart downwardly depending members, one of which is shown at 17, the other being diametrically opposite and which can be seen at 18 in Fig. 2.

Extending between the plates 17 and 18 is a rod 19 to which is pivotally mounted a locking bar 20. The pivotal movement of the locking bar 20 about the rod 19 is limited in view of abutment to the upper surface of an end region 21 with the lower of the tube-like member 12 in one direction and in the other direction by abutment of the lower surface of the end region 21 with a stop member 22.

The locking bar 20 is of a dimension so that it may be accommodated at least partially between plates 15a and 15b.

The plate member 1 not only has downwardly depending side plates 17 and 18 but also is provided with a latching element 23 adapted to extend under a part 24 of the frame 11.

When the latching element 23 extends under the part 24 of the frame 11, removal of the access cover 10 is not possible.

The tube-like member 12 has an enlarged region 26 on which is formed a thread 27. A closure member 28 is formed with a corresponding thread form so that it may be threadedly engaged within the eniarged region 26 of passageway 13.

The closure member 28 is formed with a substantially flush upper surface having three cut-outs 29, 30 and 31 so that engagement and rotational movement of the closure member 28 is possible only with a special tool.

The number of cut-outs 29, 30, 31 and their position may be specially suited so that if desired a certain number of access covers may be released by the same tool so that a single release member may enable access to the release mechanism for the latching elements on a series of covers.

The upper end of the passageway may be closed if desired by a plug 35.

In order to release the access cover, first of all the plug 35 is removed, a second release member is engaged with closure member 28 enabling it to be removed from the passageway 13.

A first release member as shown in Fig. 4 and having a shank part 40, an operating handle 41 and a head part 42 is then inserted in the passageway until a transverse member 38 provided on the locking bar 20 is positioned in a slot 43 provided in the head portion 42.

Downward movement of the first release member 40 will move the end 21 of the locking bar in a downwards direction thus moving the end 21 of the locking bar out of the channel formed by fixed plates 15a and 15b. Rotation of the release member will then cause rotation of the sleeve element 16, together with associated plate 16, latching element 23 and locking bar 20, so that the latching element 23 may be moved out of engagement with member 24 of the frame 11 to the position as shown in broken outline in Fig. 2. The access cover may then be removed from its associated frame.

To replace the access cover in position, the cover is first placed in position over its surrounding frame, the first release member inserted in position and rotated in a manner so that the latch element 23 once again engages under the frame part 24.

The locking bar 20 will take up a position as shown in bold outline in Fig. 1, because it is constructed so that the force of gravity acting thereon will cause it to take up the position as shown in bold outline. In the embodiment shown, the distance between the outer end 45 of the pivot rod 19 is greater than the distance between the pivot rod 19 and the inner end 21, thus gravity causes a clockwise turning moment.

When the latch is securely in position, the first release member may be removed, the closure member 28 is then screwed into its closed position by the second release member and the plug 35 replaced.

Whereas in the example shown both the latching element, its release mechanism and the closure member are of a relatively simple form, together they provide an unexpected high degree of security by the provision of one hiding the other and by the use of different release members to enable release of the closure member and for the latch release means, whilst enabling authorised users to readily attain access through the access cover without difficulty.

It will be appreciated that the closure member 28 may take any suitable form, its primary purpose being to prevent access to the release mechanism of the latching element and to prevent sight thereof.

It is further envisaged that the closure member 28 may have a head form or other means enabling engagement by said second release member whereby in a set of access covers, a second release member may be provided which is capable of removing the closure members 28 of all of said set and a further second closure member or members may be provided, the or each of which are capable of removing one or more of said closure members of the set but not necessarily all of the closure members. Such an arrangement enables there to be a "Master" key to open all the access covers and to permit opening of certain of the access covers, but not necessarily all, to certain authorised personnel for example.

The latching element itself may also be of any desirable form and may comprise a plurality of latching elements adapted to co-operate with any number of sides of the associated frame. Its release mechanism may also be of any suitable form and may be released only by a fairly complicated key since the ingress of dirt or foreign bodies into such mechanism is highiy unlikely in view of the provision of the cosure member 28.

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 (9)

1. An access cover provided with a movable latching element adapted to engage with an associated frame so as to secure the cover to the frame, the access cover being provided with a passageway providing access to release means for moving the latching element out of engagement with the frame by a first release member and wherein the passageway is closed or otherwise obstructed by a closure member to prevent access to the release means by the first release member, the closure member being removable or releasable only by a second release member.

2. A cover according to claim 1 wherein the closure member is spaced from an upper surface of the cover, means being provided to prevent sight of or instant access to the closure member.

3. A cover according to claim 1 or claim 2 wherein the closure member is removable from the passageway in an upwards direction.

4. A cover according to any one of claims 1 to 3 wherein the passageway is of a particular section, at least in part, to provide access only to a first release member of cooperating configuration.

5. A cover according to any one of claims 1 to 4 wherein the closure member comprises an externally threaded member which co-operates with a thread formed in the passageway.

6. A cover according to any one of claims 1 to 5 wherein the closure member has a specially formed head part enabling engagement only via the second release member which is of a corresponding special form to co-operate with the head.

7. A cover according to claim 6 where appendant to claim 5 wherein the closure member is provided with a "friction washer" or a friction compound is provided on some or all of the threads thereof.

8. An access cover substantially as hereinbefore described with reference to and as shown in the accompanying drawings.

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