US3700394A

US3700394A - Cocking mechanisms for guns

Info

Publication number: US3700394A
Application number: US686356A
Authority: US
Inventors: Norman Trevor Brint
Original assignee: UK Secretary of State for Defence
Current assignee: BAE Systems Global Combat Systems Munitions Ltd
Priority date: 1967-11-28
Filing date: 1967-11-28
Publication date: 1972-10-24
Anticipated expiration: 1989-10-24

Abstract

A cocking mechanism for a gun, comprising a rotary shaft, carried by the mounting and having intersecting right and lefthanded screw-threads and a coacting retractor member which, on rotation of the shaft, retracts the recoiling parts of the weapon, as a result of its interaction with one screw-thread, to cock certain mechanisms; whereafter run-out occurs under the influence of spring action accompanied by interaction between the retractor member and the reverse thread. The first screw-thread may be of slow pitch to give a mechanical advantage to the operator and the reverse thread of steeper pitch to give a mechanical advantage in favor of the springs.

Description

United States Patent Brint Oct. 24, 1972 [54] COCKING MECHANISMS FOR GUNS Primary Examiner-Stephen C. Bentley [72] inventor: Norman Trevor Brint, Essex, En- 4n0mey4ushman D arby & Cushman gland [73] Assignee: The Secretary of State for Defense in [57] ABSTRACT Her Britannic Maiestys Govern- A cockin g mechanism for a gun, comprising a rotary B Un'ted Kmgdom of shaft, carried by the mounting and having intersecting Great Bmam and Northern Ireland right and left-handed screw-threads and a coacting London England retractor member which, on rotation of the shaft, [22] Filed: Nov. 28, 1967 retracts the recoiling parts of the weapon, as a result of its interaction with one screw-thread, to cock cer- PP N04 686,356 tain mechanisms; whereafter run-out occurs under the influence of spring action accompanied by interaction between the retractor member and the reverse thread. [52] (5|. The first Screwthread y be of slow pitch to g a [5 "20 42/16 3 mechanical advantage to the operator and the reverse [58] new of Search 1 thread of steeper pitch to give a mechanical advantage [56] R f Cited in favor of the springs.

e erences UNITED STATES PATE 6 Claims, 2 Drawing Figures 4/ i890 Victorin ..89/20 n will PATENTED um 24 I912 3 7 00 I3 94 SHEET 1 OF 2 Inventor COCKING MECHANISMS FOR GUNS The invention relates to cocking mechanisms for guns.

In certain types of weapon, various mechanisms such as the breech mechanism, loading, extracting and ramming mechanisms require to..be cocked preparatory to loading or reloading the weapon, an action which, during a firing sequence, may be performed by the recoil movement of the gun after firing the previous round. At the start of a firing sequence, however, it may be necessary to cock these mechanisms by other means and the object of the present invention is to provide a cocking mechanism for retracting the gun relative to a cradle or mounting against spring action to produce, in effect, an artificial recoil movement which will perform the necessary cocking action.

The invention comprises a cocking mechanism for a gun, incorporating a shaft rotatably mounted in the gun cradle or mounting and having, formed thereon, intersecting right and left-handed screw-threads; a retractor member mounted upon the shaft and provided with means for engaging and retracting the recoiling parts of the gun and with at least one thread-engaging member cooperating with the said screw-threads; and means for rotating the shaft whereby the retractor member, and

hence the recoiling parts of the gun, can be retracted, against spring action, by interaction between the thread-engaging member and one of the screw-threads, to perform a desired cocking action whereafter further rotation of the shaft permits the return forward movement of the recoiling parts accompanied by interaction between the thread-engaging member and the reverse screw-thread.

The spring action opposing the retraction will normally be supplied mainly by a recoil return spring which may be assisted by various springs associated with the mechanisms to be cocked.

Various types of thread-engaging member may be employed, one example being a pair of nuts mating respectively with the two screw-threads on the shaft, with clutch means, reversible by contact with a bush at the end of its travel, for locking one or other of the nuts, according to the direction of motion, against rotation relative to the retractor member. A preferred arrangement, however, comprises a half-nut rotatably mounted in a socket carried by the retractor member and having a thread portion for engaging the screwthreaded shaft, the axis of rotation of the half-nut being radial to that of the shaft. At the end of its travel in each direction, the half-nut is diverted from one screw-thread of the shaft to the other by engagement of its tread portion with a cam surface formed on the end face of a sleeve fixed to the shaft, which cam surface causes the half-nut to rotate in its socket. The term half-nut is used herein to denote a member located alongside but not encircling the shaft and incorporating a thread engaging portion which co-operates with the screw thread to produce relative longitudinal movement between the half-nut and the shaft.

The retraction and return movement may be accomplished by continuously rotating the shaft, manually or by other convenient means, throughout the cycle but it is preferred to allow the return movement to occur under the action of the recoil return spring. With this arrangement it is desirable to use a slow pitch screw thread for retraction to provide a mechanical advantage in favor of the operator or other rotating means, with a reverse thread of steep pitch to give a mechanical advantage in favor of the recoil return spring, an arrangement compatible with use of the half-nut type of thread-engaging member.

One form of the invention will now be described, by way of example only, with reference to the accompanying drawings, the single FIGURE of which is a vertical section of part of the breech end of a weapon taken through the cocking mechanism.

A shaft 1 is rotatably mounted, parallel to the gun axis 2, in bearings 3, 4 carried by the cradle 5 or a bracket attached thereto, one at each end of the shaft 1, the bearings being retained and located by pins 3a, 4a extending through the hearing but clear of the shaft. Formed on the shaft 1 are two intersecting screwthreads, one a right-handed thread 6 of fairly slow pitch and the other a left-handed thread 7 of substantially twice that pitch. Rearward of the shaft 1 is a handle 8, mounted on a short axle 9 aligned with the shaft 1 and rotatable in a bush 10 carried by the rear wall 1 1 of the housing 5a which encloses various mechanisms associated with the weapon. This wall is hinged 12 to give access to the interior of the housing and, to permit this, the forward end of the axle 9 has, formed thereon, a diametral key 13 which engages a keyway 14 formed in a collar 15 fixed to the rear end of the shaft by a pin 16. Swinging the wall 11 outward to open the housing thus disengages the axle 9 from the shaft 1 but re-engagement occurs when the housing is closed again. The handle 8 incorporates a ratchet 17 which permits freewheeling of the axle 9, and hence the shaft 1, in a clockwise direction relative to the handle 8. Mounted on the shaft 1 and restrained against rotation by engagement with a guideway 18 in the cradle, is a slide 19 which constitutes a retractor member and carries a forwardly extending hook member 20 for engaging a forward facing surface on the breech ring 21 of the gun 22 which can, thereby, be pulled rearwardly with the other recoiling parts of the gun 22. Formed on the slide 19 is a hollow, cylindrical boss 23 whose axis is radial to the shaft 1 and in which is mounted a cylindrical half-nut 24 whose inner surface is shaped to contact the outer surface of the screw-

threads

6, 7 on the shaft 1 and has, formed thereon, a raised thread portion 25 which locates in the groove of the shafts screw-thread. At each end of the screw!-threaded part of the shaft 1 is a

collar

26, 27, fixed to the shaft by a pin 26a, 27a, the end face of each collar adjacent the screw-threads being shaped to provide a somewhat widened groove and to form a

cam surface

28, 29 respectively, such that its engagement with the thread portion 25 of the half-nut 24 will cause the half-nut to turn about its axis whereby it is diverted from one screw-thread of the shaft 1 to the other.

Starting from the rest position, clockwise rotation of the shaft 1, by manual operation of the handle 8, will cause the half-nut 24 to travel rearward along the slow pitch, right-handed screw-thread 6 of the shaft, carrying the slide 19 and the recoiling parts of the gun rearward against the action of the recoil return spring to perform the required cocking action. The arrangement of recoil return spring can take any one of any one of many forms which are so well known in the art that this item is shown schematically only, at 30. When the half-nut 24 reaches the rear end of the threaded portion of the shaft, its thread portion 25 engages in cam surface 28 of the rear collar 26 causing the halfnut 24 to rotate within the boss 23 so that the thread portion 25 is diverted into the steeper pitch, lefthanded thread 7 of the shaft. Thereafter the recoiling pans run out forwardly under the action of the recoil return spring while the shaft 1 free-wheels relative to the handle 8. This free-wheel action allows a more rapid run-out than would be achieved by continued manual operation of the shaft. On arrival at the forward end of the shaft 1 the thread portion 25 of the halfnut" 24 is diverted into the right-handed thread 6 again by engagement with the cam surface 29 on the forward collar 27.

Variations in construction of the shaft, the retractor member and its thread-engaging member within the scope of the invention will, of course, readily occur to those skilled in the art. The details of the mounting of the device, the rotating means and the means for engaging the recoiling parts will be largely dictated by the design of the weapon to which the invention is applied.

1 claim:

1. In a gun incorporating recoiling parts carried in a mounting and which requires retraction of said recoiling parts relative to the mounting to perform a desired cocking action and having spring means resisting said retraction; a cocking mechanism comprising a shaft rotatably mounted in the gun mounting; intersecting right and left-handed screw-threads formed upon said shaft, one of which threads constitutes a retracting thread and the other of which threads constitutes a reverse thread; a retractor member mounted upon said shaft; means carried by said retractor member for engaging and retracting the recoiling parts of the gun; at least one thread'engaging member carried by the retractor member and cooperating with the screwthreads on the shaft; and means for rotating said shaft whereby the retractor member and, hence, the recoiling parts of the gun can be retracted against the action of said spring means, by interaction between the thread-engaging member and the retracting thread, to perform a desired cocking action; means for diverting the thread engaging member into engagement with the reverse thread after retraction of the recoiling parts, whereafter further rotation of the shaft permits the return, forward movement of the recoiling parts accompanied by interaction between the thread-engaging member and the reverse screw-thread; and means for returning the thread engaging member into engagement with the retracting thread on completion of said forward movement.

2. A cocking mechanism as claimed in claim 1 wherein the thread-engaging member comprises a half-nut rotatably mounted in a socket carried by the retractor member; and a thread-engaging portion carried by said half-nut; the axis of rotation of the halfnut being radial to the shaft whereby it can be rotated to align the thread-engaging portion with either of the screw-threads on the shaft.

3. A cocking mechanism as claimed in claim 2 having a cam-surface at each end of the screw-threaded portion of the shaft for engagement by the thread-engaging ortion of the halfu at each end of its travel to i otate the half-nuti nits socket and divert its threadengaging portion from one screw-thread to the other.

4. A cocking mechanism as claimed in claim 1 wherein the reverse screw-thread is of steeper pitch than that engaged by the thread-engaging member during retraction of the recoiling parts.

5. A cocking mechanism as claimed in claim 1 wherein the recoiling parts are arranged to run-out under the influence of spring action and the mechanism incorporates a ratchet device by which the means for rotating the shaft engages the shaft, whereby the shaft can rotate during run-out without further rotation of said means for rotating the shaft.

6. A cocking mechanism as claimed in claim 1 incorporating a half-nut rotatably mounted in a socket carried by the retractor member and constituting the thread-engaging member; a thread engaging portion formed on said half-nut, the axis of rotation of the half-nut being radial to the shaft whereby it can be rotated to align the thread-engaging portion with either of the screw-threads on the shaft; a cam surface located at each end of the screw-threaded portion of the shaft and engageable by the thread-engaging portion of the half-nut to rotate the half nut in its socket and divert it from one screw thread to the other; and a ratchet device by which the means for rotating the shaft it connected to said shaft; the return forward movement of the recoiling parts being arranged to occur under the influence of spring action, the accompanying further rotation of the shaft occurring, by virtue of the ratchet device, without further operation of the means for rotating said shaft; and the reverse screw-thread being of steeper pitch than the screw-thread employed during retraction of the recoiling parts, whereby the mechanical advantage, during retraction of the recoiling parts, is in favor of the means for rotating the shaft and, during the return forward movement, is in favor of the spring action.

Claims

1. In a gun incorporating recoiling parts carried in a mounting and which requires retraction of said recoiling parts relative to the mounting to perform a desired cocking action and having spring means resisting said retraction; a cocking mechanism comprising a shaft rotatably mounted in the gun mounting; intersecting right and left-handed screw-threads formed upon said shaft, one of which threads constitutes a retracting thread and the other of which threads constitutes a reverse thread; a retractor member mounted upon said shaft; means carried by said retractor member for engaging and retracting the recoiling parts of the gun; at least one thread-engaging member carried by the retractor member and cooperating with the screw-threads on the shaft; and means for rotating said shaft whereby the retractor member and, hence, the recoiling parts of the gun can be retracted against the action of said spring means, by interaction between the thread-engaging member and the retracting thread, to perform a desired cocking action; means for diverting the thread engaging member into engagement with the reverse thread after retraction of the recoiling parts, whereafter further rotation of the shaft permits the return, forward movement of the recoiling parts accompanied by interaction between the thread-engaging member and the reverse screw-thread; and means for returning the thread engaging member into engagement with the retracting thread on completion of said forward movement.

2. A cocking mechanism as claimed in claim 1 wherein the thread-engaging member comprises a ''''half-nut'''' rotatably mounted in a socket carried by the retractor member; and a thread-engaging portion carried by said ''''half-nut''''; the axis of rotation of the half-nut being radial to the shaft whereby it can be rotated to align the thread-engaging portion with either of the screw-threads on the shaft.

3. A cocking mechanism as claimed in claim 2 having a cam-surface at each end of the screw-threaded portion of the shaft for engagement by the thread-engaging portion of the ''''half-nut'''' at each end of its travel to rotate the ''''half-nut'''' in its socket and divert its thread-engaging portion from one screw-thread to the other.

6. A cocking mechanism as claimed in claim 1 incorporating a ''''half-nut'''' rotatably mounted in a socket carried by the retractor member and constituting the thread-engaging member; a thread engaging portion formed on said ''''half-nut,'''' the axis of rotation of the ''''half-nut'''' being radial to the shaft whereby it can be rotated to align the thread-engaging portion with either of the screw-threads on the shaft; a cam surface located at each end of the screw-threaded portion of the shaft and engageable by the thread-engaging portion of the ''''half-nut'''' to rotate the half nut in its socket and divert it from one screw thread to the other; and a ratchet device by which the means for rotating the shaft it connected to said shaft; the return forward movement of the recoiling parts being arranged to occur under the influence of spring action, the accompanying further rotation of the shaft occurring, by virtue of the ratchet device, without further operation of the means for rotating said shaft; and the reverse screw-thread being of steeper pitch than the screw-thread employed during retraction of the recoiling parts, whereby the mechanical advantage, during retraction of the recoiling parts, is in favor of the means for rotating the shaft and, during the return forward movement, is in favor of the spring action.