GB2347735A

GB2347735A - Compressed gas cartridge for multiple discharge use

Info

Publication number: GB2347735A
Application number: GB9905655A
Authority: GB
Inventors: Robert J Lane
Original assignee: BROCOCK Ltd
Current assignee: BROCOCK Ltd
Priority date: 1999-03-12
Filing date: 1999-03-12
Publication date: 2000-09-13
Also published as: GB9905655D0

Abstract

A cartridge for storing and releasing compressed gas which comprises a regulator valve (29) arranged to control the flow of gas from a high pressure gas storage chamber (C1) to a gas discharge chamber (C3) via an intermediate chamber (C2) so that when the gas pressure in the discharge chamber (C3) reaches a predetermined value the valve (29) shuts off the flow and when the gas pressure in the discharge chamber falls the valve opens to allow gas to flow into the discharge chamber, whereby the gas discharged from the cartridge in successive discharges is maintained at a substantially constant pressure despite the falling pressure in the storage chamber as the cartridge empties. The valve (29) comprises a piston (30) which forms a passageway (33) between the intermediate chamber and the discharge chamber and is movable into and out of contact with a seal which closes the passageway, the seal being adjustable to vary the pressure in the discharge chamber at which the valve (29) shuts off the flow of gas from the storage chamber (C1) into the discharge chamber (C2).

Description

COMPRESSE GAS CARTRIDGE FOR MULTIPLE DISCHARGE USE. ESPECIALLY IN RELATION TO SMALL ARMS This invention relates to cartridges for storing and releasing compressed gas, e. g. compressed air, for use with small arms such as air guns and air pistols, or other similar devices that require release of short bursts of pressurised gas when operated.

Various designs of such cartridges are known and in some cases they are intended for multiple discharge use before being replaced or recharged. For multiple discharge use, however, there can be a problem in ensuring that there are not wide variations in the pressure of the gas discharged over a series of successive discharges from the same cartridge, i. e. in multi-shot use. An object of the present invention is accordingly to provide an improved form of cartridge especially suitable for multi-shot use.

According to the present invention a cartridge for storing and releasing compressed gas incorporates therein a regulator valve between a high pressure gas storage chamber and a gas discharge chamber, the regulator valve being arranged to permit the flow of gas from the storage chamber into the discharge chamber but being operable in response to the resulting increase in gas pressure in the discharge chamber to shut off such flow when the pressure in the discharge chamber reaches a predetermined value, whereby the gas discharged from the cartridge in successive discharges is maintained at a substantially constant pressure despite the falling pressure in the storage chamber as the cartridge empties.

Preferably the regulator valve is provided with means for adjusting the operation of the valve to vary the pressure in the discharge chamber at which the valve shuts off the flow of gas from the storage chamber into the discharge chamber.

By way of example, one embodiment of the invention is illustrated in the accompanying drawings. In this embodiment the compressed gas cartridge intended for use in small arms such as air guns is in the form of a capsule adapted to be charged with compressed gas, preferably compressed air, and recharged after emptying.

In the drawings: FIGURE 1 is a side view of the air capsule; FIGURE 2 is a longitudinal section through the air capsule; FIGURE 3 is an end view of the capsule; FIGURE 4 is an end view showing the other end of the capsule, and FIGURE 5 shows, by means of exploded views, the individual components and the assembly thereof in building up the capsule of FIGURE 1.

Referring to the drawings, the capsule comprises a hollow cylindrical body 10 defining a gas storage chamber C 1. This chamber can be filled with air, usually at a pressure of 3000psi, through an opening 11 at one end of the capsule. This opening is normally closed by a valve 12 comprising a valve spool 13 fitted with two'0'rings 14 and 15 of different sizes (see FIGURE 5), the outer, larger ring 14 engaging a valve seat formed around the opening 11.

The valve spool 13 is supported by one end of a cylindrical stem 16 extending through the chamber C 1 coaxially with the capsule body, the other end of the stem extending into a blind bore 17 formed in a grub screw 18. The stem is a sliding fit in this bore, which may be hexagonal in shape, so that when the capsule is being charged the pressure of the air from the supply forces open the valve 12, the larger'0'ring 14 carried by the spool 13 being disengaged from the valve seat and the stem 16 sliding further into the blind bore 17. When the chamber Cl has been filled with air at a pressure of 3000 psi, the inner, smaller '0'ring 15 acts on the outer ring to urge it back into engagement with the valve seat thereby to reclose the valve. If desired, a spring (not shown) may be provided to assist closure of the valve.

The grub screw 18 is engaged with a screw thread formed in a bore in a body 19 which closes the end of the chamber C 1 remote from the filling opening. This body 19 has an externally screw-threaded portion engaged with an internal screw thread 20 in the capsule body 10, a seal 21 being located between the two bodies.

The body 19 defines a chamber C2 which communicates with the storage chamber Cl via radial bores 22 and the gaps between the screw thread 20 of the capsule body 10 and the cooperating screw thread of the body 19.

When the capsule is filled with air, therefore, this chamber C2 contains air at 3000psi.

The body 19 is formed with an internally screw-threaded bore 23 which receives an externally screw threaded portion of a further body 24. This body 24 defines a discharge chamber C3 which when the capsule is fitted to an air gun is placed in communication with an air storage chamber in the gun through an outlet opening 25. This opening is normally closed by a one-way valve 26 which, when the capsule is fitted to a gun, is opened by an actuator pin on the gun, thereby allowing air to flow from the chamber C3 into the storage chamber of the gun. The valve 26 comprises an axially movable valve element 27 and a plastics seal 28 which engages a valve seat around the opening 25.

The flow of air from the chamber C2 to the chamber C3 is controlled by a regulator valve 29. This valve comprises a piston 30 fitted with an'0' ring and axially slidable in a cylinder bore 31 formed in the body 24. The piston has a hollow stem 32 which together with a hole in the piston forms a passageway 33 between the chambers C2 and C3. A sealing member 34 is provided between the two bodies 19 and 24 to close the end of the piston cylinder and the stem 32 extends through a bore in this member and an aligned bore in the body 19 so that on movement of the piston 30 to the left as viewed in FIGURE 2 the stem projects into the chamber C2 and eventually comes into contact with a seal 35 mounted in a recess in the grub screw 18 with the result that this seal closes the adjacent end of the passageway 33 and shuts off the flow of air from the chamber C2 to the chamber C3. A coil spring 36 is arranged to urge the piston in the opposite direction.

The regulator valve is operable to maintain the air in the discharge chamber C3 (and the storage chamber in the gun) at a constant pressure, usually a pressure within the range of approximately 900-1100 psi, for successive discharges in multi-shot use. When the capsule is fitted to the gun the chamber C3 contains air at atmospheric pressure. The spring 36 therefore urges the piston 30 to the position shown in FIGURE 2. Air at 3000psi can therefore flow from chamber C2 through the passageway 33 into chamber C3. As a result the air pressure in chamber C3 increases and as this happens the air forces the piston to the left against the action of the spring. When the air pressure in the chamber C3 reaches the desired constant value, the stem of the piston comes into contact with the seal 35 thereby closing the passageway and preventing further air entering the chamber C3.

When the air gun is fired the air in the chamber C3 and the storage chamber in the gun is released in a short burst, whereupon the piston 30 returns to its original position under the action of the spring, thereby allowing air to flow into the chamber C3 until the pressure therein again reaches the desired constant value.

As the air pressure in the capsule storage chamber decreases, the air pressure created in the chamber C3 for each shot will nevertheless always be stabilised at the desired constant value, the regulator valve simply allowing more air to flow into the chamber until the piston reaches the closed position.

This position can be adjusted, and hence the air pressure created in the chamber C3 varied, by adjusting the grub screw to move the seal 35 to the left or right, such adjustment being effected during assembly of the capsule.

It will be appreciated that this design of air capsule is well adapted to provide for multi-shot or multiple discharge operation. Also, by locating the regulator valve within the cartridge capsule, a particularly compact selfcontained assembly is provided. Many detail variations and modifications may be made, however, and it will also be appreciated that the scope of the invention is not limited to the specific detail features of the embodiment which has been described merely by way of example.

Claims

CLAIMS 1. A cartridge for storing and releasing compressed gas which comprises a regulator valve between a high pressure gas storage chamber and a gas discharge chamber, the regulator valve being arranged to permit the flow of gas from the storage chamber into the discharge chamber but being operable in response to the resulting increase in gas pressure in the discharge chamber to shut off such flow when the pressure in the discharge chamber reaches a predetermined value, whereby the gas discharged from the cartridge in successive discharges is maintained at a substantially constant pressure despite the falling pressure in the storage chamber as the cartridge empties.
2. A cartridge as claimed in Claim 1 wherein the regulator valve is provided with means for adjusting operation of the valve to vary the pressure in the discharge chamber at which the valve shuts off the flow of gas from the storage chamber into the discharge chamber.
3. A cartridge as claimed in Claim 1 or 2 wherein the regulator valve comprises a piston slidable in a bore in a body of the cartridge and provided with a hollow stem which together with a hole in the piston forms a passageway through which gas can flow from the storage chamber into the discharge chamber, the stem being movable in one direction under the pressure of gas in the discharge chamber into contact with a seal which closes the passageway and thereby shuts off the flow of gas into the storage chamber when said pressure reaches the aforesaid predetermined value.
4. A cartridge as claimed in Claim 3 wherein a spring acts on the piston so that when the gas pressure in the discharge chamber falls it urges the piston in the opposite direction to open the valve and thereby allows gas to flow into the discharge chamber until the pressure therein again reaches the aforesaid predetermined value.
5. A cartridge as claimed in Claim 3 or 4 wherein the seal is adjustable to vary the aforesaid predetermined value.
6. A cartridge as claimed in any one of the preceding claims wherein the regulator value is arranged to control the flow of gas into the discharge chamber from an intermediate chamber which is in communication with the storage chamber.
7. A cartridge as claimed in Claim 6 wherein the intermediate chamber is formed in a body which is attached to a body defining the storage chamber, the said chambers communicating with one another through gaps between the bodies and radial bores formed in the body defining the intermediate chamber.
8. A cartridge as claimed in Claim 7 wherein the discharge chamber is formed in a further body attached to the body defining the intermediate chamber, the regulator valve being mounted in this further body.
9. A cartridge for storing and releasing compressed gas, substantially as herein described with reference to, and as illustrated in the accompanying drawings.