Captive piston projectile and method of manufacture

Patent metadata

Field	Value
Publication number	US-2022113121-A1
Application number	US-201917309914-A
Country	US
Kind code	A1
Filing date	Nov 27, 2019
Priority date	Jan 4, 2019
Publication date	Apr 14, 2022
Grant date	—

Abstract

A captive piston projectile ( 40 ) comprising a payload housing ( 43 ), a piston assembly attached to the payload housing ( 43 ), and actuation means ( 46 ) for urging the piston assembly from a stowed configuration to an extended configuration. The piston assembly comprises a tubular piston member ( 41 ) attached around the periphery of the payload housing ( 43 ), the attachment optionally being in the form of a circumferential groove ( 42 ) within which the piston member ( 41 ) can slide. This provides increased thrust whilst maintaining payload volume. Particularly suited to use with barrelled weapons, and also relates to a method of manufacture.

First claim

1 . A captive piston projectile for launching from a gun barrel, comprising a payload housing, a piston assembly attached to the payload housing, and actuation means for urging the piston assembly from a stowed configuration to an extended configuration, such that in use the piston assembly urges against the breech of a gun barrel to thrust the projectile from the barrel, wherein the piston assembly comprises a tubular piston member attached around the periphery of the payload housing.

2 . The captive piston projectile of claim I wherein the tubular piston member is collapsible such that in the stowed configuration it is collapsed against the payload. housing.

3 . The captive piston projectile of claim 2 wherein the tubular piston member comprises a bellows portion.

4 . The captive piston projectile of claim 3 wherein in the stowed configuration the bellows portion is folded perpendicular to the axis of the captive piston projectile.

5 . The captive piston projectile of claim 2 wherein the tubular piston giber comprises a plurality of telescoping sections.

6 . The captive piston projectile of claim 1 wherein the tubular piston member is arranged to slide with the payload housing, such that in the stowed configuration the payload housing is at least partially received into the tubular piston member.

7 . The captive piston projectile of claim 6 wherein the payload housing comprises a circumferential groove into which the tubular piston member is arranged to slide.

8 . The captive piston projectile of claim 7 herein the circumferential groove comprises an end stop, the tubular piston member comprising a protrusion that abuts the end stop when in the extended configuration, such that the tubular piston member is retained within the circumferential groove.

9 . The captive piston projectile of claim 6 wherein the tubular piston member is internally tapered.

10 . The captive piston projectile of claim 6 further comprising stabilisation fins retractably attached to the tubular piston member.

11 . The captive piston projectile of claim 10 wherein the stabilisation tins are recessed into respective longitudinal slots in the tubular piston member when the tubular piston member is in the stowed configuration.

12 . The captive piston projectile of claim 10 wherein the stabilisation fins are biased outwards of the tubular piston member.

13 . The captive piston projectile of claim 12 wherein the stabilisation fins are configured to act as detents for holding the captive piston projectile at a predetermined position inside a gun barrel.

14 . The captive piston projectile of claim 6 further comprising a vent means for venting gases compressed by action of the tubular piston member sliding with the payload housing.

15 . The captive piston projectile of claim 14 wherein the vent means comprises vent grooves defined between the tubular piston member and the payload housing.

16 . The captive piston projectile of claim 15 wherein the vent grooves are arranged to extend partway along the length of either the tubular piston member or the payload housing, such that in the extended configuration gases compressed by action of the tubular piston member sliding with the payload housing are trapped to provide an air cushion.

17 . The captive piston projectile of claim 1 wherein the actuation means comprises a propellant cartridge in fluid connection with the tubular piston member, such that in use propellant gases can flow into the tubular piston member to urge the piston assembly into its extended configuration.

18 . The captive piston projectile of claim 17 further comprising vent holes in the tubular piston member.

19 . The captive piston projectile of claim 17 wherein the tubular piston member is sealed to the payload housing, such that propellant gases are retained between the tubular piston member and payload housing.

20 . An ammunition round comprising a projectile casing and the captive piston projectile of claim 1 .

21 . A method of manufacturing a captive piston projectile, comprising steps of:
a) Providing a payload housing; b) Attaching a tubular piston member around the periphery of the payload housing, the tubular piston member being adjustable between a stowed configuration and an extended configuration; c) Arranging an actuation means to urge the tubular piston member from the stowed configuration to the extended configuration when the captive piston projectile is in-use.

22 . The method of claim 21 wherein the step of attaching a tubular piston member comprises the step of configuring the tubular piston member to slide with the payload housing between the stowed configuration and the extended configuration.

23 . The method of claim 22 wherein the step of configuring the tubular piston member to slide comprises the step of locating the tubular piston member inside a circumferential groove of the payload housing.

Assignees

• Secr Defence

Inventors

• Cooke Samuel Brendan Dixon

Classifications

• F42B5/184

  telescopic · CPC title

• F42B5/10 Primary

  with self-propelled bullet · CPC title

• F42B5/045 Primary

  of telescopic type (F42B5/184 takes precedence) · CPC title