GB2556318A

GB2556318A - A Guard for a cylinder of pressurised gas

Info

Publication number: GB2556318A
Application number: GB1611993.5A
Authority: GB
Inventors: Witt Dorian; Dorner Wolfgang
Original assignee: Linde GmbH
Current assignee: Linde GmbH
Priority date: 2016-07-11
Filing date: 2016-07-11
Publication date: 2018-05-30
Also published as: GB201611993D0

Abstract

A guard for a pressurised gas cylinder 1 comprising a collar with a screw thread for engaging with the neck 3 of the gas cylinder. An upstanding portion 9 projects up from the collar to protect a valve on the top of the cylinder. The collar has a split ring configuration forming a gap 10 and a screw is provided across the gap. The screw 11 has a thread portion which engages with a screw threaded bore on one side of the gap. The screw head bears against the other side of the gap such that screwing the screw into the bore causes the gap to close and hence and tighten the collar. There is an obstruction in the collar positioned on the opposite side of the screw head to limit the extent to which the screw head can move.

Description

(54) Title of the Invention: A Guard for a cylinder of pressurised gas Abstract Title: Guard for pressurised gas cylinder (57) A guard for a pressurised gas cylinder 1 comprising a collar with a screw thread for engaging with the neck 3 of the gas cylinder. An upstanding portion 9 projects up from the collar to protect a valve on the top of the cylinder. The collar has a split ring configuration forming a gap 10 and a screw is provided across the gap. The screw 11 has a thread portion which engages with a screw threaded bore on one side of the gap. The screw head bears against the other side of the gap such that screwing the screw into the bore causes the gap to close and hence and tighten the collar. There is an obstruction in the collar positioned on the opposite side of the screw head to limit the extent to which the screw head can move.

FIG. 2

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

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- 1 A Guard for a Cylinder of Pressurised Gas

The present invention relates to a guard for a cylinder of pressurised gas, the guard comprising a collar with a screw thread for engaging with a corresponding screw thread on the neck of the gas cylinder and an upstanding guard portion projecting upwardly, in use, from the collar to protect a valve on the top of the cylinder, the collar having a split ring configuration forming a gap where the ring is split, a screw is provided across the gap, the screw having a threaded portion which engages with a screw threaded bore on one side of the gap and a screw head which bears against the bearing face on the other side of the gap such that screwing the screw into the bore causes the head to bear against the bearing face to close the gap and tighten the collar.

Such a guard will subsequently be referred to as “of the kind described”.

A guard of the kind described is well known in the prior art. The split ring configuration allows the guard to be used for cylinders which have screw threads of slightly different diameters. This allows the single guard to fit with a W80 neck made according to European standards. The split ring also allows the guard to be threaded onto the neck of the gas cylinder until it reaches the correct rotational position in which an opening in the guard is aligned with an access point of the cylinder valve. Once in place, the screw is tightened to close the gap and firmly attach the guard to the cylinder.

Once in place, it may be 10 years or more before the guard needs to be removed. During this time, the guard is likely to be stuck reasonably firmly to the screw thread on the cylinder. Thus, while the screw should be relatively easy to unscrew from the collar, the guard remains hard to dislodge from the cylinder.

According to the present invention, a guard of the kind described is characterised by an obstruction in the collar positioned on the opposite side of the screw head to the bearing face to limit the extent to which the screw head can move away from the bearing face.

Once the screw head hits the obstruction, continuing rotation of the screw causes the part of the collar with the screw threaded bore to be pushed away from the obstruction inevitably widening the gap. This increases the diameter of the collar generating a force which tends to pull the screw thread on the collar away from the screw thread on the neck

-2of the gas cylinder. This allows a relatively high force to be easily generated in precisely the manner necessary to dislodge any adhesion which may have occurred between the screw threads.

The obstruction may be anything which will limit to the extent which the screw head can move away from the bearing face. It may, for example, be an indent formed in the collar. However, preferably it is in the form of a pin insertable into aligned openings in the collar. This provides a simple mechanism whereby the pin can easily be put in place once the screw is in place. It also provides a reliable way of limiting the movement of the screw head even when a relatively high force is applied.

The pin may be a rigid component which provides an interference fit in the aligned holes, but is preferably a resilient component which is easier to insert. More preferably, it is a hollow split pin which can be compressed to a smaller diameter in order to fit in the aligned opening, but which will then resiliently deform to a larger diameter to remain securely within the aligned openings.

The screw may be provided with a lateral feature on its head to allow engagement with a tool onto the side of the screw head. For example, it may be a hexagonal thread for engagement with a spanner or a lateral hole which can be engaged with a lever. However, preferably, the screw has a tool engaging feature in the end facing the obstruction and the obstruction is positioned so as not to obstruct the tool engaging feature. This means that a tool such as a screw driver or Allen key can be inserted into the tool engaging feature in order to rotate the screw.

The collar is preferably provided with a recess on the side of the gap which receives the screw thread, the recess being configured to substantially accommodate the screw head and the obstruction being positioned adjacent to a radially innermost face of the recess. This recess provides a low profile design in which the screw head can largely be protected from external impact. It also ensures that the obstruction can be in a position in which it is also protected and in which it also does not obstruct the tool engaging feature.

An example of a guard in accordance with the present invention will now be described with reference to the accompanying drawings, in which:

-3Fig. 1 is a perspective view of a portion of the guard shown fitted onto the neck of the cylinder; and

Fig. 2 is a cross-section in the horizontal plane through the centre of the screw.

As shown in Fig. 1, a cylinder 1 has a shoulder 2 at its upper end leading into a neck 3 provided with a screw thread 4. On top of the cylinder is a valve 5 to allow pressurised gas to be released from the cylinder, as well as allowing the cylinder to be refilled. A guard 6 has a collar 7 with a screw thread 8 which is complimentary to the screw thread 4 on the neck of the cylinder 1. Upwardly projecting guard portions 9 extend upwardly from the collar to protect the valve 5 and also to provide a handle for the cylinder as is well known in the art.

The collar 7 has a split ring configuration with a gap 10 being formed in the split ring. As can be seen in Fig. 1, this gap is away from the guard portions 9. A screw 11 passes across the gap 10 and, at its distal end, has a screw thread 12 which fits into a bore 13 with a complimentary screw thread 14. The screw 11 also passes through a hole 15 in the collar 7 on the opposite side of the gap 10. As shown in Fig. 2, there is no screw thread in this portion as this is unnecessary, but there is no reason why there cannot be a screw threaded engagement here also. A recess 17 is formed in the side of the collar 7 creating a bearing surface 18 against which the head 19 of the screw 11 bears via a washer 20.

The head 7 has a hexagonal recess 21 to receive an Allen key to allow rotation of the screw 11.

The recess 17 is provided with a through hole 22 in its lowermost face. There is also an aligned blind bore (not shown) in the top surface of the recess. A split pin 23 which is formed from a rolled sheet of metal is inserted through the hole 22 into the blind bore such that it is retained in the position shown in the Figures. This is done after the screw 11 is inserted.

As will be apparent from the Figures, the presence of the pin 23 prevents the screw 11 from being moved away from the bearing surface 18 by more than a small amount. The pin 23 could directly abut against the head 19, but a small gap is desirable in order to allow the screw threads 12, 14 to begin to disengage from one another before the head 19 hits the pin 23. Once the head 19 hits the pin 23, continued rotation of the pin 11 causes the threads 12, 14 to disengage from one another, but as the pin 11 cannot move any further to

-4the right in Fig. 2 because it is blocked by the pin 23, this further movement opens the gap 10 further. This has the effect of enlarging the collar 7 circumferentially pulling the screw threads 4, 8 away from one another thereby loosening the engagement between these threads which is likely to have become stuck over the passage of time. Once loosened in this way, the guard 6 can then be unscrewed from the neck of the cylinder 1.

Claims

CLAIMS:

1. A guard for a cylinder of pressurised gas, the guard comprising a collar with a screw thread for engaging with a corresponding screw thread on the neck of the gas cylinder and an upstanding guard portion projecting upwardly, in use, from the collar to protect a valve on the top of the cylinder, the collar having a split ring configuration forming a gap where the ring is split; a screw is provided across the gap, the screw having a threaded portion which engages with a screw threaded bore on one side of the gap and a screw head which bears against the bearing face on the other side of the gap such that screwing the screw into the bore causes the head to bear against the bearing face to close the gap and tighten the collar;

characterised by an obstruction in the collar positioned on the opposite side of the screw head to the bearing face to limit the extent to which the screw head can move away from the bearing face.

2. A guard according to claim 1, wherein the obstruction is in the form of a pin insertable into aligned openings in the collar.

3. A guard according to claim 2, wherein the pin is resilient.

4. A guard according to claim 3, wherein the pin is a hollow split pin which can be compressed to a smaller diameter in order to fit in the aligned opening, but which will then resiliently deform to a larger diameter to remain securely within the aligned openings.

5. A guard according to any one of the preceding claims, wherein the screw has a tool engaging feature in the end facing the obstruction and the obstruction is positioned so as not to obstruct the tool engaging feature.

6. A guard according to any one of the preceding claims, wherein the collar is provided with a recess on the side of the gap which receives the screw thread, the recess being configured to substantially accommodate the screw head and the obstruction being positioned adjacent to a radially innermost face of the recess.

GB1611993.5

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