GB787574A - Improvements in or relating to aiming devices on or for weapons for combatting mobile targets - Google Patents

Abstract

787,574. Sighting devices. MATHEMA CORPORATION REG. TRUST. Feb. 12, 1954, No. 4142/54. Class 92 In an anti-aircraft gun, the aiming device comprises a drag roller 9, Fig. 5, movable over the surface of a rotatable sphere 7 and means 8, 4 moving the drag roller relative to the surface of the sphere in two planes disposed at 90 degrees to each other in proportion to the angle of sight y and to the bearing angle # respectively whereby the roller 9 is adjusted into the apparent angle of flight # by a turning movement in the plane containing its rotational axis 11 and about an axis perpendicular to the surface of the sphere 7. This turning movement or the drag roller is used in the sighting device to rotate an opaque disc 27, Figs. 5, 6 with transparent curves 28 indicating aiming-off values for selected target speeds and a superposed disc 29 with a radial slot 30 provides a luminous radial line, the intersection of this line and one of the curves selected for the estimated target speed being the point which is maintained on the target, the optical axis of the sight, which is parallel to the gun barrel, then being directed towards the strike point. A hemisphere 4, Fig. 5, is rotated through the angle of sight y by means of a shaft 5 and at the same time is rotated through the bearing angle # via the bevel gears 6. At the point of contact between the hemisphere 4 and the sphere 7 a drive speed of # # cos γ is obtained. A roller 8 is disposed at 90 degrees to the drive plane and drives the sphere 7 through the angle of sight y. The resultant velocity is recorded through the drag roller 9, whereby the rotation of the roller 9 on the axis 11 gives the angular velocity in the plane of flight and the turning of the roller 9 around the shaft 10 gives the apparent angle of flight #. This turning movement is conveyed by gearing to the discs 27, 29 connected by a shaft 35 on which a frame 37 is rotatably mounted, the disc 27 being mounted on the frame. A guide rim 34 is displaced by an eccentric disc 38 in the direction of a guide slot 39 by the valve cot # the rim 34 serving as a guide for a roller 33 rotating on a shaft 36 carried by the frame 37. Since the frame 37 with the shaft 35 is rotated proportional to the angle #, the frame 37 together with the disc 27 is rotated on the shaft 35 approximately proportional to cot γ cos # which is equal to cot # # where # # is the bearing angle in the plane of flight. The aiming-off curves 28 are indicated in relation to cot # # and the intersection of the luminous radial line provided by the slot 30 with a selected curve will indicate the point to be maintained on the target.