GB2188714A - Riot control weapon - Google Patents

Abstract

A man-portable gas-operated riot control weapon is provided in which the energy imparted to the round 29 on firing is automatically adjusted through a coupling to the range-finder sight (not shown) as the target is ranged. A chamber 24 in a cylinder 13 on one side of a piston 21 constitutes a variable volume accumulator, the position of the piston along the cylinder being adjusted automatically during ranging. After each firing, the accumulator is recharged from a gas bottle via a gas pressure regulator, charging taking place when the weapon is cocked. <IMAGE>

Description

SPECIFICATION Improved riot control weapon This invention relates to man-portable riot control weapons.

In the control of riotous assemblies arms are used by security forces that are intended to stop targetted individuals without killing or maiming them. One such weapon is a handgun firing so-called baton rounds, i.e. rubber bullets, instead of lethal rounds. However, even baton rounds fired at close range can sometimes maim or kill and therefore personnel carrying such arms are instructed not to fire when the range is less than a certain distance. Mistakes have nevertheless occurred, it being not easy for an individual to make a calm estimate of range in a rapidly-changing emotionally-charged situation, with the result that the confidence of security forces in the use of such arms is adversely affected. There is thus a need for a better weapon that does not become dangerous to the target as the range decreases.

According to the invention, a man-portable gas-operated gun is provided which has means for varying the operative gas pressure charge which means is coupled with a rangefinder sight such that upon operation of the range-finder the operative gas pressure charge is automatically adjusted to achieve a substantially constant target impact energy over a considerable range of target distances. Preferably, the operative gas pressure charge is a substantially fixed pressure, variable volume, charge.

One embodiment of the invention wili now be described by way of example with reference to the accompanying drawings.

The gun shown in the drawings has a barrel 10, a breech 11 loaded from a semi-automatic magazine 12, a variable volume air accumulator 13 beneath the barrel and breech and supplied with air under pressure from a replaceable high pressure air bottle 14 at the rear of the weapon, a trigger and cocking mechanism 15 and trigger valve 16 and a range-finding sight 17. The air bottle 14 is screw-threadedly connected to a diaphragm type gas pressure regulator 18 and supplies air under pressure to the gas regulator through a self-sealing valve which opens when the bottle is firmly screwed in. The gas regulator is fitted at its downstream side with a pressure relief valve 19.

The variable volume air accumulator 13 comprises a horizontal cylinder 20 in which slides a piston 21 having a piston rod 43 and also connected to an oppositely-extending lockable rod 22. The chambers 23, 24 in the cylinder on opposite sides of the piston can be put into communication with one another by operation of a pressure-equalising spool valve 25. The chamber 23 at the end of the cylinder 20 nearer the gun muzzle is always pressurised with air from the gas regulator, at a pressure regulated down to, say, 300-400 p.s.i., when there is an air bottle fitted. The other cylinder chamber 24 is, however, only pressurised when the pressure-equalising valve is opened during a gun-cocking operation.The piston 21 can be moved manually to different positions along the cylinder, thereby varying the volume of the chamber 24, a locking device 27 serving to lock the rod 22, and thus the piston 21, in any of a large number of positions of adjustment.

The cylinder chamber 24 communicates through a large flow-area passage 28 with the end of the breech chamber 29, the breech end port being formed as a seating 30 for the trigger valve 16 which is urged on to this seat by a spring 32 and prevents admission of air under pressure into the breech except when the trigger 31 is pressed. The trigger operates the trigger valve by turning a springloaded sear 35 to which the trigger is coupled by a pivotal link 36.

With a round in the breech, the gun is cocked by a thumb-operated cocking lever 33 that turns a cam 34 which opens the equalising valve 25 and also locks the trigger 31 by raising an abutment face 37 to block movement of the sear 35. The chamber 24 of the accumulator 13 is thus pressurised and the trigger valve is now urged on to its seat by differential pressure. Further movement of the cocking lever 33 brings a lever tail 38 into engagement with the locking device 27 to unlock the rod 22. The locking device consists of two pivotally-mounted half-nuts 39, 40 which are spring-loaded to clamp on to a buttress screw-thread 41 on the rod 22, such that the piston load tends to increase the grip.

However, the equalising of pressure on opposite sides of the piston 21, by opening of the equalising valve during the initial movement of the cocking lever, removes the piston load from the locking device and enables the lever tail 38 to release this lock.

With the locking device 27 released and the pressure on opposite sides of the piston 21 equalised, the piston can readily be slid along the cylinder 20. The trigger, however, remains locked. The gun is now brought to the aiming position and the target is sighted and ranged by moving a hand-grip 42 horizontally along the gun. A suitable sight is a stadiametric range-finding sight in which pairs of vertical bars on a graticule at different spacings are matched to the shoulder width of the target, the adjustment being achieved by movement of a mask with a letter-box window vertically up and down the graticule. This vertical move ment not only provides the ranging function but can also be arranged to give the correct gun elevation for the particular range. How ever, the particular form of this ranging sight is per se not part of the present invention.

It will be observed that the direct function of the ranging hand-grip 42 is to move the piston rod 43, and hence the piston 21 and the rod 22, along the cylinder 20. A convenient way to convert this horizontal motion to the vertical motion required for the gun sight is by providing a gear 44 in mesh with the screw-thread on the rod 22 and rotating about a vertical axis, the gear having its top surface formed as an inclined cam face to actuate a vertical push rod 45. By this means, the volume charge of air under pressure in the chamber 24 is automatically varied to match changes in range setting, this charge being admitted to the breech chamber to propel the round from the gun when the trigger is pressed.

When the gun sight has been adjusted to the correct range, the cocking lever 33 is released and returns to its initial position, whereupon the equalising valve re-closes and the trigger is unlocked. Pressing of the trigger then causes the sear 35 to release an annular shuttle piston 46 surrounding the stem 47 of the trigger valve 16. The shuttle piston has a small amount of axial float on the valve stem and is now moved back by the air pressure in the passage 28, against the action of a spring 48, until the shuttle reaches an abutment 49 on the valve stem. Since the shuttle piston has a greater effective area than the effective area keeping the trigger valve on its seat, the pressure bias on the trigger valve is reversed and the valve and shuttle now move together away from the valve seat 30.As soon as air under pressure begins to enter the breech chamber 29, the trigger valve opens rapidly to its fullest extent and the round in the breech is propelled down the rifled gun barrel by the entering air pressure charge.

When the gun has been fired and the charge of propellant air has exhausted, the spring 32 reseats the trigger valve 16 and the weapon is ready for reloading. For de-pressurising the chamber 24 without firing the gun, a knurled knob 50 at the side of the gun body can be turned to vent this chamber to atmosphere. A manual safety catch 51 prevents the trigger 31 from being operated until the catchis released.

The magazine 12 containing further rounds projects laterally from the side of the breech 11 and is detachable for loading. Rounds are inserted into the magazine against the pressure of a spring 52 and retained by a springloaded latching bar 53 located in slots in the magazine mouth. When the magazine 12 is clipped to the breech 11, the latching bar can be retracted by operating a handle 54 thereby allowing the rounds 55 to bear against the exterior of the breech under spring pressure.

The breech has a loading aperture 56 facing into the mouth of the magazine which is ordi narily covered by an external sleeve 57. To open the breech the sleeve 57 is rotated manually about the breech to bring an aperture 58 in the sleeve into alignment with the breech loading aperture 56, which permits a round from the magazine to enter the breech after which the breech is reclosed.

The sleeve 57 rotates eccentrically to a small degree with respect to the breech and its wall thickness varies progressively in the circumferential direction, a leaf spring 59 being provided between the breech wall and the sleeve wall at the thinnest portion of the sleeve. The arrangement is such that as the sleeve is rotated into the closed position a thick wall portion alongside the sleeve aperture enters into the gap in the breech wall constituting the breech loading aperture 56, due to the eccentric rotation and the action of the spring, and this traps the round loaded into the breech in a concentric position in the breech. This, of course, still leaves the breech inside wall surface with a discontinuous portion around its circumference but so long as the round is retained concentrically in the breech the gap or discontinuity has no material effect on the firing of the round and a small amount of leakage of air from the breech on firing is of no significance.

Claims (12)

1. A man-portable gas-operated gun with means for varying the operative gas pressure charge which means is coupled with a rangefinder sight such that upon operation of the range-finder the operative gas pressure charge is automatically adjusted to achieve a substantially constant target impact energy over a considerable range of target distances.

2. A gun according to Claim I, wherein the operative gas pressure charge is a substantially fixed pressure, variable volume, charge.

3. A gun according To Claim 2, comprising a variable volume gas accumulator supplied with gas under pressure from a resevoir of gas under pressure via a gas pressure regulator, and a trigger valve operable to admit pressure gas from the gas accumulator into the breech chamber.

4. A gun according to Claim 3, wherein the variable volume gas accumulator comprises a cylinder with a piston slidable therein to vary the cylinder volume on one side of the piston, the piston being coupled to the range-finder sight whereby when the gun is ranged the position of the piston along the cylinder is automatically adjusted.

5. A gun according to Claim 4, wherein the piston has two gas chambers on opposite sides of the piston, one constituting the variable volume accumulator while the other is pressurised initially and remains pressurised when and after the gun is fired, a pressureequalising valve connects the two chambers, and gun-cocking means is provided which, when operated, opens the pressure-equalising valve to equalise the gas pressure on opposite sides of the piston.

6. A gun according to Claim 4, further comprising locking means for the piston which locking means is unlocked by movement of the cocking means to its fully operative position and is relocked when the cocking means is released.

7. A gun according to Claim 5 or Claim 6, wherein a trigger mechanism is provided to operate the trigger valve, which trigger mechanism is locked when the cocking means is operated and unlocked when the cocking means is released.

8. A gun according to any one of Claims 3 to 7, wherein the trigger valve is operated by differential pressure.

9. A gun according to any one of Claims 3 to 8, further comprising a manually operable vent for exhausting the variable volume accumulator.

10. A gun according to any one of the preceding claims, comprising a magazine containing further rounds projecting laterally from the breech of the gun, and wherein the breech has a loading aperture facing into the mouth of the magazine and a rotary apertured external sleeve to open and close the loading aperture.

11. A gun according to Claim 10, wherein the sleeve rotates with a small degree of eccentricity and its wall thickness varies progressively in the circumferential direction in an arrangement such that as the sleeve is rotated into the closed position a thick wall portion thereof alongside the sleeve aperture enters the aperture in the breech wall and traps the loaded round in a concentric position in the brecch.

12. A riot control weapon substantially as described herein with reference to the accompanying drawings.