GB2160282A - Security cover - Google Patents

Abstract

A security cover for releasably fitting over a member (for example a gas pipe connector or terminator cap) to which unauthorised access is to be denied, comprises a cover 30 shaped to fit over the member 6 and a concealed catch (44, 48) supported by the cover 30 and engageable with the member 6 so that the cover 30 cannot be removed therefrom; a source of fluid under pressure (e.g. air compression pump 56) is screwed temporarily to the cover 30 and fluid supplied thereby is delivered to the piston 44 of the catch 44, 48 to release the cover 30. <IMAGE>

Description

SPECIFICATION Security cover This invention concerns a security cover.

A security cover is known which is intended to prevent access to a rotatable member which has one or more shaped regions specifically provided to be engaged by a separate turning tool. When the cover is in place direct access to the rotatable member is denied.

One example of the use of such a known security cover is to deny access to a screw threaded nut shaped to be engaged for turning by an appropriate spanner. Another example is to prevent a bolt being turned by a spanner. A further example is to prevent a screw having a slot at one end from being turned by a screw-driver.

Such a security cover can be required for various reasons, one of which reasons will be understood from the following description of situations encountered in the supply of gas.

It is known to supply gas to premises from the mains through a control valve connected to a length of supply pipe leading to the inlet to a gas meter. The pipe can be connected to the valve through a coupling releasably attached to an outlet tube from the valve by a nut engaging an external thread on the tube.

When the gas supply is cut-off permanently from the premises, for example, for non-payment of gas bills, the nut is released from the control valve outlet tube so that the pipe to the meter is disconnected from the valve. To prevent escape of gas should the valve be opened, its outlet tube is then blanked-off by a nut-like cap tightened onto the outlet tube thread using a spanner. To deter unauthorised removal of the blanking cap and reconnection of the meter to the valve, the cap is engaged by a wire which is wound around some other component and then its two ends are clamped in a seal of lead or other durable material.

Nevertheless some people ignore these measures and unlawfully break the seal wire.

unscrew the cap and reconnect the meter to the supply. As the gas authority believes the supply to be cut-off no check may be made for a long time during which a considerable amount of gas may have been consumed illegally and possibly by then the lawbreakers have vanished.

Gas meters usually have externally threaded inlet and outlet tubes to which are respectively connected the supply pipe and a distribution pipe leading to a gas consuming appliance. The connections are made by couplings comprising nuts threadably engaging the meter inlet and outlet tubes. A gas meter is intended to record the amount of gas supplied by displaying a number which increases according to how much gas has passed through the meter from its inlet to its outlet. By releasing the coupling nuts, the meter connections can be reversed. This can cause certain meters to count backwards. Thus the number displayed progressively decreases as the amount of supplied gas increases.Therefore by manipulation of the meter connections between meter readings taken by the gas supply authority that authority can be deceived into thinking a lesser amount of gas has been consumed than is actually the case.

It is an object of the invention to provide a security cover which can be adapted so that perpetration of the aforesaid deceits can be prevented or at least made more difficult.

According to the invention, there is provided a security cover for releasably fitting over a member to which unauthorised access is to be denied, comprising a body shaped to fit over the said member, and a catch supported by the body and movable relative thereto between first and second positions, the catch being arranged such that in the first position it engages the said member when the cover is fitted thereon so as to prevent removal of the cover and in the second position enables the cover to be fitted onto or removed from the said member, wherein the catch is supported in the body so that access to it is restricted at least when the catch is in the first position, means are provided for releasably connecting a source of fluid under pressure to the body and for delivering fluid under pressure from the source to the catch, and the catch is arranged to be moved from the first to the second position by fluid under pressure delivered from the source.

Preferably, the cover is rotatable relative to the said member when the catch is in the first position so that rotation of the cover body does not cause rotation of the said member.

The cover body may be in the form of a cup which may be placed mouth first over the said member.

The catch may comprise a pin axially movable in a passage extending through the body, the pin being movable along the passage between the first position in which it projects from the passage and the second position in which it is located wholly within the passage.

The catch may comprise a piston sliding in a cylinder defined by the passage, the delivered fluid under pressure being supplied to the cylinder so as to move the piston to the second position and retract the pin.

A conduit may extend from the cylinder to a formation provided at the exterior of the body which formation is adapted for detachable engagement by said source of pressurised fluid.

The source of pressurised fluid may be a pump, for example a manual pump.

The pressure fluid may be a gas. for example air. In the case of pressurised gas the source may be a container of the pressurised gas from which the gas may be selectively releasable in any desired quantity.

The piston and pin may be movable to the first position in response to manual force transmitted to the piston. For this purpose the cylinder may be open at one end at the exterior of the body so that a pushing member, for example a small rod, may be inserted into the open end to push the piston and pin in the first direction.

Alternatively the cylinder may be closed at an end thereof remote from the pin, and the cover body adapted so that the pin and piston can be pushed in said first direction also by pressurised fluid. For this purpose the body may be further adapted for engagement by said source of pressurised fluid and a further conduit extend through the body from the cylinder for connection with the source. The cup-shaped body may have an aperture in its base to fit about a projection of the said member, and the opening of the passage for the pin may be in the wall of the aperture, the projection being formed with an annular groove engagable by the pin when the latter is moved to the first position.

The invention will now be further described, by way of example, with reference to the accompanying drawings in which Fig. 1 is a perspective view of a conventional blanking cap for blanking off a gas supply to premises; Fig. 2 is an inverse plan of the cap in Fig.

1; Fig. 3 is a view partly in section of the cap of Fig. 1 in use in known manner.

Fig. 4 is a perspective view of a security cover formed according to the invention in position over the cap screw mounted as in Fig. 3; Fig. 5 is a perspective view from below of the security cover of Fig. 4; Fig. 6 is a section on an enlarged scale on the line IV-IV in Fig. 4; Fig. 7 is a section on line Ill-Ill in Fig. 6.

connected to a source of pressurised fluid; Fig. 8 is a fragment of the section in Fig. 7 showing the catch in released attitude; Fig. 9 is a perspective view of a variation of the security cover in Figs. 4 to 8; Fig. 10 is a section of a modification of the security cover in Figs. 4 to 8, in which the modification can be used on a pipe coupling, and Fig. 11 is a horizontal section of a modification of the cover in Fig. 10.

A known arrangement for cutting off a gas supply to premises is shown in Figs. 1 to 3 in which a connection between a gas control valve and a gas meter (not shown) is interrupted by removal of a coupling nut (not shown) from screw thread 2 on a pipe 4 from the control valve, and the pipe 4 is sealed by a screw-on metal blanking-off cap 6 in the form of a nut having flats 8 for gripping by a spanner and pressing on sealing ring 10. Cap 6 has an upstanding spigot 12 annularly grooved at 14 to leave an overhanging lip or collar 16 just below which is a diametral bore through which a wire 18 is threaded and then wrapped about pipe 4 before the ends of the wire are gripped by a crimped-on seal 20 intended to make the cap inviolate. Which it is not, because after wire 18 has been broken the cap may be readily unscrewed.

To prevent that, the security cover 30 of Figs. 4 to 8 is provided. The cover comprises a cup-shaped body 32 which may be of metal, for example brass, of cylindrical internal shape having a relatively thick base 34 formed with a central aperture 36 which fairly closely fits about the spigot 12 when the body is fitted cup-mouth first over the cap 6 to completely cover the latter so a spanner cannot be applied to the flats 8 to unscrew the cap. Also because of the cylindrical internal shape of the body 32 and the fact that its internal diameter exceeds the external diameter of cap 6 means the cover cannot engage the cap in the manner of a spanner either.

Within the thick base 34 is a radial cylinder 38 opening at one end to the outer periphery of the body and from its other end extends a co-axial passage 40 opening out in the wall 42 of the aperture 36. Cylinder 38 contains a piston 44 engaging a sealing ring 46. Integral with the piston is a co-axial pin 48 which can slide through the passage 40 and through a closely surrounding stationary sealing ring 50 held at the shoulder between the passage and the cylinder 38.

From the attitude shown in Fig. 8, the piston and pin are movable to that in Figs. 6 and 7 merely by pushing the piston by a slender pusher, for example a narrow screwdriver or nail, inserted through the wider open end of the cylinder 38 so that the pin 48 enters the annular groove 14 in which the pin engages the collar 16 to retain the cover should an attempt be made to lift the cover off the cap. The piston is now sufficiently inset into the cylinder, and the diameter of the cylinder is sufficiently small and the piston diameter is sufficiently close to that of the cylinder that the piston (which is non-magnetic) is inaccessable for the purpose of pulling it back along the cylinder.

At one end a conduit 52 opens into the cylinder 38 between the seals 46, 50, and at its other end at the bottom of a screwthreaded, blind ended bore 54 extending in the cup bottom 34 from the cylindrical outer periphery of the latter.

A source of fluid pressure, for example an air compression pump 56, has a threaded nozzle 58 by which the pump is detachably attachable to the bore 54. The pump comprises a barrel 60 defining a cylinder 62 swept by a piston 64 integral with a screw 66 engaging the barrel and manually turned by handle 68. A sealing ring 70 can be carried on the nozzle to make a fluid tight seal between the pump and the cover 30.

To release the cover, the pump is screwed thereto, and the piston is screwed down to increase the air pressure in cylinder 62 and conduit 52. That air pressure compresses the seal 50 and applies an axial outward force to the seal 46 and to the end of piston 44 surrounding the pin 48. This combination of forces moves the piston 44 outwardly along cylinder 38 thus retracting the pin 48 to the position shown in Fig. 8 to allow the cover to be removed. Without the use of a specially adapted source of fluid pressure it is very difficult if not impossible to release the security cover 30, especially since the pin 48 and piston 44 remain within the general overall volume defined by the body.

An abutment may be provided, if desired, to stop the piston 44 emerging from the cylinder 38. On the other hand it is known that the force due to air pressure on the piston 44 will decrease due to decrease in air pressure when the air volume in the cylinder 38 between the seals 46 and 50 increases due to outward movement of the seal 46 within the piston. Therefore taking account of the retarding force due to dynamic friction of the seal rings 46, 50, it is possible to ensure the force of the air pressure drops below the retarding force so that the piston 44 stops before emerging from the cylinder 38.

The security cover 30A in Fig. 9 is a variation of the cover in Figs. 4 to 8 in as much as the outer surface of the body 32 has flats to make it appear like a nut and the cupbase 34 has upstanding tube part 72 externally screw-threaded for coupling to a pipe which may lead to a gas meter. In this way the security cover 30A is disguised to appear like part of normal pipe coupling arrangement, so the fact it is masking a blanking off cap may well deceive any uninformed person making a cursory examination of the arrangement.

In the modification shown in Fig. 10, the cover 30B masks a coupling nut 80 used to couple together two pipes 82 and 84, and pipe 82 being threaded to engage the nut and the other pipe 84 compressing a sealing washer 86 and having a collar 88 engaged by an inturned lip 90 of the nut. In the cover 30B, the aperture 36 is enlarged to accommodate the pipe 84 formed with an annular groove 14B to receive the locking pin 48.

Fig. 11 shows a horizontal section of a cover 30C which is a modification of that in Fig. 10. In this modification the body 32 has a protruberence 90 on its side in which the threaded bore 54 is formed and is connected by the conduit 52 to the cylinder 38 which is closed at its outer end 92 and limited at its inner end by tightly fitting bush 94 apertured for the pin 48 to slide therethrough. The bore shown at 38' is formed during the drilling of the cylinder 38. Bore 38' may be filled in.

Another threaded bore 96 for engagement by the pump 56 is provided connected by a conduit 98 to the outer end of the cylinder 38. To move the pin 48 into its locking position with groove 14B in Fig. 10, the piston and pin are propelled radially inwardly by pressurised air supplied on the conduit 98 from the pump.

It will be appreciated that the covers in Figs. 4 to 10 may be modified for movement of pin into locking position by air pressure as in Fig. 11. If desired the bore 96 in all cases could be disposed in the side of the body similarly to the bore 54 in Figs. 4 to 10 without the provision of the protruberence 90.

Claims (11)

1. A security cover for releasably fitting over a member to which unauthorised access is to be denied, comprising a body shaped to fit over the said member, and a catch supported by the body and movable relative thereto between first and second positions, the catch being arranged such that in the first position it engages the said member when the cover is fitted thereon so as to prevent removal of the cover and in the second position enables the cover to be fitted onto or removed from the said member, wherein the catch is supported in the body so that access to it is restricted at least when the catch is in the first position, means are provided for releasably connecting a source of fluid under pressure to the body and for delivering fluid under pressure from the source to the catch, and the catch is arranged to be moved from the first to the second position by fluid under pressure delivered from the source.

2. A security cover according to claim 1, wherein the cover is rotatable relative to the said member when the catch is in the first position so that rotation of the cover body does not cause rotation of the said member.

3. A security cover according to claim 1 or 2, wherein the cover body is in the form of a cup which is placed mouth first over the said member.

4. A security cover according to any preceding claim, wherein the catch comprises a pin axially movable in a passage extending through the body, the pin being movable along the passage between the first position in which it projects from the passage and the second position in which it is located wholly within the passage.

5. A security cover according to any preceding claim, wherein the catch comprises a piston sliding in a cylinder defined by the cover body, the delivered fluid under pressure being supplied to the cylinder so as to move the piston to the second position.

6. A security cover according to claim 5, wherein a conduit extends from the cylinder to a formation provided at the exterior of the body which formation is adapted for detacha ble engagement by said source of pressurised fluid.

7. A security cover according to any preceding claim, wherein the said source of pressurised fluid is a pump.

8. A security cover according to any one of claims 1 to 6, wherein the said source of pressurised fluid is a container of pressurised gas from which gas may be selectively released.

9. A security cover according to any preceding claim, wherein the catch is movable from the second to the first positions by manual force.

10. A security cover according to any one of claims 1 to 8, wherein the catch is movable from the second to the first positions by the supply of pressurised fluid to the catch from said source of pressurised fluid.

11. A security cover substantially as hereinbefore described with reference to Figs. 4, 5, 6, 7 and 8, Fig. 9, Fig. 10 and Fig. 11.