GB723586A - - Google Patents

Abstract

723,586. Ordnance mountings. BREVETS AERO-MECANIQUES SOC. ANON. July 16, 1952 [July 30, 1951], No. 18020/52. Classes 92(1) and 92(2). Relates to guns having a movable sighting device with an optical axis fixed with respect thereto, and a servomechanism interconnecting the movable sighting device, the gun, and the gun stand in such a manner that, when the gun layer tends to track a target, an angular interconnection complying with a predetermined law is maintained between the optical axis and the line of fire in response to displacements imparted by the layer to the sighting device. According to the invention, means are provided to enable the layer to choose at will between a limited number and preferably two different laws of interrelation between the displacements of the optical axis of the sighting device and the line of fire. In Fig. 1 the gun 2, gunner's seat 67, and sighting device 5 are carried by a frame 3 so that they move with the frame around a stand 1 when following a target in azimuth. With the target moving as shown in Fig. 2 the sight is moved in a clockwise direction and serves, by a toothed quadrant, to move a sleeve 24 to the right, to enable fluid from a source 27 to drive a training motor 30. This motor not only drives gears 17, 18, to move the frame 3 around the stand 1 but also the sun-wheel 35 of a differential gear. The planet gear of the differential, by means of a screw 37, serves to move the piston 26 of the sleeve 24 in a direction opposite to that in which the sleeve has moved, and also to traverse the carriage 41 of a variable speed device over the surface of a disc 42 driven at a constant speed. The balls of the device drive a cylinder 39 geared to the other sun wheel of the differential. When the device is correctly tracking a moving target the two sun wheels are rotating at the same speed and the sight, which has to be readjusted after its initial movement, is at the correct angle with respect to the line of fire. A switch 47 carried by one of the sight control handles 21 may be closed to energize an electromagnet 46 when the sight is swung through a large angle to pick up a target, the action of the magnet being to withdraw a gear 33 from the chain of gears between the motor 30 and differential gear. When the switch is closed the gun follows the movement of the sight without any lead angle, for in this case the piston 26 will remain in, or return to, its neutral position.