Patent GB-671599-A (GB)
Title: Improvements in or relating to ammunition feeding means
Inventor: CHAPMAN JAMES E
IPC: F41A9/51
Filed: 1950-04-18
Abstract: 671,599. Ammunition feeding devices. GARRETT CORPORATION. April 18, 1950. No. 9467/50. Class 92 (ii). [Also in Group XXIV] An ammunition feed booster comprises a feed sprocket 43 driven from a motor 37 through a compound planetary gear system, the drive including two orbit members 42, 61 of which one (42) is connected to the sprocket and is initially held against rotation by the load thereon while the other (61) is thereby given an initial rotary movement, such movement serving to lock the rotated orbit member whereupon further rotation of the shaft 56 of the driving motor serves to drive the orbit member connected to the feed sprocket. In the construction shown belted ammunition in a box 12 is fed by the booster 20, arranged within the box, through a chute 13 to the gun 10. The gun is fired by pressing a push-button switch 15 which is also in circuit with the motor 37 of the booster. The motor is secured to one end wall of the box 12 and is surrounded by a rotatably mounted tube 42 which is fitted with sprocket wheels 43 for engaging and feeding the ammunition towards the gun. To the opposite wall of the box 12 is fitted a cap 49 comprising elements 50, 51 and cam member 52, the element 51 being fitted with a bearing 54 for one end of the tube 42. Within the cap and having a limited degree of rotation is an anti-rollback clutch 80 fitted with loosely mounted rollers 83 which can engage both with the shaft 56 of the motor and internal cam surfaces 85 of the fixed cam plate 52. A spring 88 tends to rotate the clutch to the position in which the rollers are pressed by the cam surfaces to lock the shaft against rotation. A sun wheel 57 on the shaft 56 engages gears 74 on a compound planetary gear 74, 75, the gears 74 meshing also with an internal gear 60 of the tube 42 and the gears 75 with an internal gear on a locking ring 61 ; the gear 74 is larger than gear 75. By this arrangement, when the ring 61 is locked by rollers 65 arranged between it and the cam plate, as shown in Fig. 6, the spider 68 carrying the planet gears 74, 75 is rotated by the gear 57 around the motor shaft and drives the tube 42 to feed ammunition towards the gun. Operation. The mechanism permits the tube 42 to free wheel in the feeding direction, clockwise in Fig. 6, when the motor is idle, so that the ammunition belt may be passed over the sprockets 43 and up the ammunition chute to charge the gun; the rollers 65 do not lock the ring 61 against rotation during this operation. If the belt is to be withdrawn at any time a pull may be exerted on a hook 90, Fig. 3, attached to the spring 88 to move the rollers 83 to release the shaft 56 and thus to permit reverse rotation of the tube 42. A switch 95 in the motor circuit is normally closed to drive the motor'when firing the gun but is opened by the belt when the latter buckles. The drive from the motor is transmitted to the belt feed tube 42 by the sun and planet gearing, as described above, the rollers 65 being moved automatically to the locking position. When firing ceases, any tendency of the belt to move in the reverse direction is prevented by the rollers 83 which are moved by spring 88 to a position to lock the shaft 56 ; during firing the shaft moves these rollers along the cam surfaces 85 to the release position. Further, on ceasing fire the advancement of the belt is arrested and the gearing prevents rotation of the motor in the feeding direction ; the belt also flexes at substantially the same time and opens the switch 95 in the motor circuit.