Patent GB-745868-A (GB)
Title: Ammunition booster with torque limiting device
IPC: F41A9/51
Filed: 1953-11-23
Abstract: 745,868. Feeding ammunition to guns. GARRETT CORPORATION. Nov. 23, 1953 [Dec. 1, 1952], No. 32400/53. Class 92 [Also in Group XXIV] An ammunition feed booster comprises power means, ammunition rotary feeding means driven by said power means including a movable element 38 positioned in response to variations in countertorque, and control means for said power means actuated through the movement of said element. The cartridges 14, Fig. 1, are urged along a shoot 13 by sprockets 11, 12 on a drum 22, Fig. 2, the latter housing a driving motor 23. The drive from the motor to the drum is similar in many respects to that disclosed in Specification 671,599, in that it comprises a, gear 28, on shaft 27, driving a spider 33 having pairs of gears 36, 37; gear 36 is larger than 37 and meshes with a gear 29 on drum 22, while gear 37 engages teeth on a ,rotatable tubular member 31. A member 38, see also Fig. 3, surrounds shaft 27 and has recesses 39 fitted with idlers 40, these being adapted to wedge between the parts 38, 31, when member 31 is driven clockwise by motor 23, and thus lock member 31 against further movement; subsequent to such locking the drive from the motor rotates the drum 22. In Specification 671,599 the member (38) was stationary, whereas in the present invention it has a limited rotary movement against an opposing biasing force provided by a coiled spring 48 which is anchored at one end to a fixed cupped member 46 and at the other end to a tubular hub 43 secured to the member 38. Within the hub 43 and connected to it by a spring 58 is a member 52 fitted with a shaft 59 carrying a cam 70, Fig. 6, adapted to rock a lever 77 associated with a switch 80 for the motor 23. Action. When switch 80 is closed the motor 23 rotates shaft 27 anticlockwise, Fig. 3, and before the load on the drum 22 is overcome the gear assembly serves to rotate the member 31 clockwise, thus locking it to member 38, which then moves clockwise to stress the spring 48. When the countertorque thus provided is sufficiently great the gear assembly serves to drive the drum 22 anti-clockwise thereby feeding the cartridges along the shoot 13. The member 52 moves with the member 38 thus rotating the cam 70. If the force to be overcome in feeding the cartridges exceeds a predetermined value, the consequential increased rotation of member 38 is such that the cam 70 moves the lever 77 to open the switch 80 to deactivate the motor 23. The motor is also stopped by the opening of another switch 89, Fig. 1, when the last cartridge leaves the sprockets 11, 12. For this purpose an opening 83 in the shoot is normally closed by a spring-urged door 84 having a projection 87 engaging with a switch button 88. When the last cartridge leaves the sprockets the door can swing further inwards and in doing so operates the switch. Anti-rollback clutch. The member 52 carries rollers 56, Figs. 2 and 3, which engage shaft 27 and are normally moved by the shaft to the outer ends of cam surfaces 57 in the member 38. If, however, the shaft should move in the reverse direction, due to retrogressive movement of the ammunition belt, the rollers are moved by the spring 58 to a wedging position between the surfaces 57 and the shaft 27. Such reverse movement may, however, be permitted when desired by a manuallyoperable cable 63 which serves to rotate a pulley 61 loose on the shaft 59, the pulley having a pin adapted to engage with the cam 70 so that it can rotate the cam and with it the member 52 carrying the rollers. 56.