GB2278149A - Security cover - Google Patents

Abstract

A security cover for protecting for example simple nuts from unauthorised access. The cover is in the form of a pair of body components 1, 2 which may be locked together in a closed configuration around a surface to be protected. A pneumatically operated locking mechanism is provided which comprises a bolt 8 which can be manually engaged with a pin 5 to lock the cover in a position and released by fluid pressure applied at 9 and acting via passage 10. <IMAGE>

Description

SECURITY COVER The present invention relates to a security cover and in particular to a cover for positioning around an annular surface to prevent access to that surface.

The gas distribution industry suffers from the theft of fuel gas by individuals who make unauthorised connections to the distribution system. When a gas supply is installed to any individual premises, the pipe entering those premises is closed by a suitable termination.

When the premises are subsequently occupied and an authorised user is to be connected to the supply, the termination is removed, a meter is connected to the incoming gas supply pipe, and an outlet of the meter is connected to a distribution system within the premises. If the supply to the premises is subsequently cut off, a gas control valve upstream of the meter is first closed, the inlet to the meter is then disconnected from the incoming pipe, and the incoming pipe is closed with a suitable termination. The termination is conventionally a very simple threaded plug type and unfortunately such a termination can be readily removed by an unauthorised individual using very simple tools.

With a view to deterring individuals from removing such terminations, it has been proposed to provide a security cover which can be fixed in position on the termination and when so positioned prevents access to the termination unless a special tool is available.

This arrangement is described in British Patent No. 2160282. The security cover described in that specification incorporates a locking pin which engages in a slot in the termination to prevent the cover being lifted from the termination. The locking pin is in the form of a piston slidably received within the security cover and can be displaced to a position out of engagement with the slot only by supplying pressurised air to the piston using a purpose made tool.

The known security cover has proved effective in significantly reducing the theft of fuel gas as a result of unauthorised individuals re-connecting supplies. Unfortunately fuel gas is being stolen in circumstances where the known security cover is not effective. In particular, it is known for authorised users of fuel gas supplies to disconnect the meter which is used to measure consumption of gas and connect a bypass pipe between the two connectors that are normally connected to the gas meter. If the meter is read relatively infrequently which is normally the case, the user can re-connect the meter periodically so that the meter is always in place when inspected.

The result is that the user pays for some of the gas that is consumed but for much of the time takes gas from the system without being charged.

It is an object of the present invention to provide a security cover which is capable of addressing the problem outlined above.

According to the present invention, there is provided a security cover for positioning around an annular surface to prevent access to that surface, the cover being arranged to be positioned in either a closed configuration in which it defines a closed ring or an open configuration in which the ring is split to enable it to be placed around a surface to be covered, wherein a locking mechanism is provided to lock the cover in the closed configuration, the locking mechanism comprising first and second locking members which are interengageable to lock the cover in the closed configuration and spaced apart when the cover is in the open configuration, the first locking member being movable from a first position in which it engages the second member to lock the cover if the cover is in the closed configuration and a second position in which it cannot engage the second member, the first locking member being supported in the cover so that access to it is restricted at least when in the first position, means being provided for delivering fluid under pressure to the first locking member, and the first locking member being arranged to be moved from the first position to the second position by fluid under pressure delivered thereto.

Generally the second locking member will be fixed in position relative to the cover. If so, the second locking member may be in the form of a separately manufactured component such as a pin which is permanently secured to the cover or an integral formation defined by the cover.

Preferably the cover comprises two body components which are interengageable by a hinge, the first and second locking members being supported on respective body components. The hinge enables separation of the two body components if the cover has been unlocked and the first and second locking members have been moved apart.

Preferably, the first locking member is in the form of a piston located in a bore in the cover, the second locking member is in the form of a pin which extends at least partially across the bore when the cover is in the closed configuration, and the piston and pin are of irregular cross-section such that when the cover is in the closed configuration and the piston is in the first position the pin engages the piston and cannot be withdrawn from the bore. Fluid under pressure may be delivered from an actuator comprising a piston which is engageable in a cylinder which communicates with the bore such that movement of the actuator piston in the cylinder pumps air into the bore and pushes the locking member piston along the bore towards the second position.The actuator piston may be supported in an actuator body that may be secured into a socket that communicates with the bore, the actuator piston being movable relative to the actuator body by turning a feed screw, and the actuator body when screwed into the socket providing an airtight seal to prevent leakage from the bore through the socket. The socket may be vented on the side of the seal remote from the bore to enable pressurised fluid to leak from the socket.

Preferably one end of the first locking member is manually accessible to enable its movement from the second position to the first position by the application of a manual force.

An embodiment of the present invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a side view of an embodiment of the present invention in the closed configuration; Fig. 2 is a side view of the two components making up the embodiment shown in Fig. 1 after their separation to split the cover; Figs. 3 and 4 are respectively views in the direction of arrows 3-3 and 4-4 in Fig. 1; Figs. 5 and 6 are respectively views taken on the lines 5-5 and 6-6 of Fig. 2; Fig. 7 shows sections through the components shown in Fig. 2 in offset planes parallel to the plane of Fig. 2; and Fig. 8 is a part sectioned exploded view of an actuator which is used to release the cover illustrated in Figs. 1 to 7.

Referring to Figs. 1 to 7, the illustrated security cover comprises two C-shaped body components 1, 2 which may be interconnected to form a closed ring as shown in Fig. 1 or split as shown in Fig. 2. Body component 1 supports a projecting flange 3 which may be inserted into a mating slot 4 defined in the body component 2 so as to define a hinge. The body component 2 supports a fixed pin 5 with an enlarged head which, when the cover is closed as shown in Fig. 1, is received in a blind bore 6 defined by the body component 1.

The bore 6 communicates with a further blind bore 7 in which a piston 8 is slidably received. The inner end of the bore 7 communicates with a further threaded bore 9 through a passageway 10.

The threaded bore 9 defines a socket which is in communication with a passageway 11.

When the cover is in the closed configuration shown in Fig. 1, the pin 5 is received within the bore 6 and the enlarged head of the pin 5 extends beyond the bore 7. If the piston 8 is in the position shown in Fig. 5, the pin 5 can move freely along the length of the bore 6. In contrast, if the pin 8 is in the position shown in Fig. 6, the relatively large end of the piston obstructs the bore 6 and therefore prevents the passage of the head of the pin 5 across the bore 7.

The end of the piston 8 is accessible through the open end of the bore 7. Thus if the two body components are moved to the closed configuration as shown in Fig. 1 with the piston 8 in the position shown in Fig. 5, the piston 8 can then be pushed further into the bore 7 by applying a force with a suitable tool to the end of the piston 8.

This locks the two cover body components together. Although the end of the piston 8 can still be touched there is no way in which it can be withdrawn from the bore 7 as a result of such contact. To enable withdrawal of the piston, the actuator device illustrated in Fig. 8 must be inserted into the threaded bore 9.

Referring to Fig. 8, the illustrated actuator comprises a body 12 with a threaded tip 13 supporting a sealing ring 14. The body defines a cylinder 15 into which a piston member can be inserted. The piston member has a knurled surface 16 at one end, a threaded section 17 adapted to engage a thread 18 in the actuator body, and a sealing ring 19 adapted to form a seal within the cylinder 15. If the actuator body is screwed into the threaded bore 9, the ring 14 makes a seal with a smooth walled portion at the base of the bore 9. The actuator piston is then inserted into the actuator body and rotated so that the cooperating threads 17 and 18 drive the piston ring 19 towards the actuator tip. This pressurises air within the cylinder 15 which is pumped through the passageway 10 into the bore 17.The piston supports a sealing ring 20 which prevents the air pumped into the bore 7 from leaking past the piston 8. Accordingly the pressure bearing against the piston builds up and the piston is driven upwards in Fig. 6 until it assumes the position shown in Fig. 5. Although not shown the edge of the opening from which the bore 7 extends will be deformed to prevent the piston 8 being blown out of the body.

Thus an individual provided with an actuator will be able to readily displace the piston 8 and thereby release the lock. Without such a tool it would be extremely difficult to move the piston. In particular, if an alternative source of pressurised gas, for example a bicycle pump, was pressed against the opening of the bore 9, even if gross leakage from the vicinity of the bore opening could be prevented the passageway 11 would nevertheless cause the pressurised air to escape and the pressure required to displace the piston 8 would not be achieved. Thus the illustrated cover can be locked in the closed ring configuration very readily and only released from that locked configuration by a person provided with the appropriate tool.

The threads in the actuator are both left-handed to make it more difficult to produce a copy tool.

As may be appreciated from Figs. 5 and 7, each of the cover body components 1 and 2 supports a radially inwards extending flange 21 on each of its axial edges. This flange enables the cover to be locked around a nut the diameter of which is greater than the inner diameter of the flanges 21 but the diameter of which is less than the diameter of the cover between the flanges 21. The cover that may thus be locked onto any nut of an appropriate size to which access is to be denied. Once the cover is in place, it can be turned easily around the nut but there is no means for applying sufficient force to the nut to cause it to be undone. Thus the cover can be used in many applications, for example to prevent the disconnection of appliances connected to a gas supply pipeline.It will of course be appreciated however that the present invention is applicable to any circumstances where a member such as a nut must be made inaccessible to simple tooling.

The described device could be readily removed by a determined individual with for example a hacksaw. If this was done, however, it would be immediately apparent that the cover had been tampered with and this would enable for example a gas supply company to take appropriate measures to protect their interests.

Although in the described embodiment the cover is in the form of two body components which can be completely separated, the simple hinge defined by the flange 3 and slot 4 could be replaced by a full hinge which would prevent separation of the two components.

Alternatively it might be practical to fabricate the cover from plastics material which would be sufficiently flexible to enable the cover body to be fabricated from a single piece of material.

Claims (9)

1. A security cover for positioning around an annular surface to prevent access to that surface, the cover being arranged to be positioned in either a closed configuration in which it defines a closed ring or an open configuration in which the ring is split to enable it to be placed around a surface to be covered, wherein a locking mechanism is provided to lock the cover in the closed configuration, the locking mechanism comprising first and second locking members which are interengageable to lock the cover in the closed configuration and spaced apart when the cover is in the open configuration, the first locking member being movable from a first position in which it engages the second member to lock the cover if the cover is in the closed configuration and a second position in which it cannot engage the second member, the first locking member being supported in the cover so that access to it is restricted at least when in the first position, means being provided for delivering fluid under pressure to the first locking member, and the first locking member being arranged to be moved from the first position to the second position by fluid under pressure delivered thereto.

2. A cover according to claim 1, comprising two body components which are interengageable by a hinge, the first and second locking members being supported on respective body components.

3. A cover according to claim 2, wherein the hinge enables separation of the two body components if the cover has been unlocked and the first and second locking members have been moved apart.

4. A cover according to any preceding claim, wherein the first locking member is in the form of a piston located in a bore in the cover, the second locking member is in the form of a pin which extends at least partially across the bore when the cover is in the closed configuration, and the piston and pin are of irregular crosssection such that when the cover is in the closed configuration and the piston is in the first position the pin engages the piston and cannot be withdrawn from the bore.

5. A cover according to claim 4, wherein the means for delivering fluid under pressure comprises an actuator piston which is engageable in a cylinder which communicates with the bore such that movement of the actuator piston in the cylinder pumps air into the bore and pushes the locking member piston along the bore towards the second position.

6. A cover according to claim 5, wherein the actuator piston is supported in an actuator body that may be secured into a socket that communicates with the bore, the actuator piston being movable relative to the actuator body by turning a feed screw, and the actuator body when screwed into the socket providing an airtight seal to prevent leakage from the bore through the socket.

7. A cover according to claim 6, wherein the socket is vented on the side of the seal remote from the bore to enable pressurised fluid to leak from the socket.

8. A cover according to any preceding claim, wherein one end of the first locking member is manually accessible to enable its movement from the second position to the first position by the application of a manual force.

9. A cover substantially as hereinbefore described with reference to the accompanying drawings.