Patent GB-626684-A (GB)
Title: Improvements in or relating to bombsights
IPC: F41G3/24
Filed: 1943-01-16
Abstract: 626,684. Bombsights. HILLIER, H. (Sperry Gyroscope Co., Inc.). Jan. 16, 1943, No. 858. [A Specification was laid open to inspection under Sect. 91 of the Acts, July 19, 1943.] [Class 92 (ii)] Apparatus for applying corrections to one or more controls of a bombsight when the aircraft is climbing or gliding comprises means for causing the aircraft to climb or glide at a constant rate and for simultaneously adjusting the setting of the control or controls to compensate for the change in altitude. In the construction shown in Fig. 1, a shaft 83 is connected to an altitude-controlling automatic pilot, such as that described in Specification 626,285, [Group XXXV], and is driven through shaft 79 and ball-carriage and disc mechanism 71, 65 by a constant speed motor 63. The speed of the driven shafts, and hence the rate of change in altitude of the aircraft, is determined by the adjustment of a control 69 which, through rack-and-pinion mechanism 73, 75, displaces the ball-carriage. Shaft 79 also drives a disc 85 which in turn drives a shaft 105 through a ball carriage 89, the latter being adjusted by a control 93 which also actuates a dial 99 indicating the required correction for the time-of-fall. The speed of rotation of shaft 105 is thus determined by the settings of the two controls 69 and 93 and its movements are conveyed by a selsyn transmitter and cable 109 to a receiver which positions the usual time-offall setting control of the bombsight, such as that described in Specification 624,554. Similar mechanism driven by the shaft 79 and incorporating a control 117, dial 127 and transmitter 123 is provided for applying corrections to the trail setting control of the bombsight. In a modification, the manual controls 93 and 117 are dispensed with and their respective ball carriages are adjusted by cams actuated by the shaft 79. In another modification, Fig. 3, the motor 63 drives a shaft 169 geared to three discs 85, 113 and 65, each associated with a ball carriage positioned respectively by controls 93, 117 and 69, serving the same purposes as those shown in Fig. 1. Ball carriages 89, 115, of discs 85, 113, drive shafts carrying arms 187, 175, sweeping over a number of contacts 185, 177, each of which is connected to a corresponding contact 165 on a member 163. Sweeping over contacts 165 is a semicircular member 161 connected to a battery and mounted on the shaft 70 of control 69, which shaft also carries a star-wheel 239. A pawl engaging the star-wheel ensures that shaft 70 is rotated step by step, each movement making the member 161 connect one more or one less of the contacts 165. Thus, the number of voltage impulses applied to arms 187, 175 in a unit of time depends on the setting of controls 93, 117 and also of control 69. The arm 187 is electrically connected to solenoids 213 and 215, Fig. 4, associated with the time-of-fall control mechanism of the bombsight. This mechanism includes a shaft 191 to which is fitted a shaft 197 carrying a two-way ratchetwheel 199, two arms 201, 203 joined by a spring 221, and a manual control knob 193. The arms carry spring-controlled pawls 205, 207, between which projects a pin 219 fitted to a plunger 217 entering the solenoids. In operation, each time an impulse is applied to the arm 187 one of the solenoids is energized and the pin 219 causes one of the pawls 205, 207 to engage and rotate the wheel 199, thus imparting a correction to the bombsight. Similar mechanism is associated with the arm 175 which is suitably connected to solenoids provided to operate the trail setting control of the sight. The selection of the particular solenoid of the two solenoids 213, 215 to be energized depends on whether the aircraft is set for climbing or gliding and is effected automatically by switches 245, 247, Fig. 3, suitably actuated by a cam 246 on the shaft 70.