Patent GB-1053988-A (GB)
IPC: G03B9/08
Abstract: 1,053,988. Photogrammetric cameras. CARL ZEISS VEB. March 26, 1964, No.12953/64. Heading G2A. A photogrammetric camera has an electric motor controlling a first cam disc arrangement acting as a pulse generator, the two being connected together by a coupling controlled by a second cam disc arrangement also acting as a pulse generator, the latter being operated by the same motor; the pulses generated are utilized to operate the camera shutter. In the form shown, the electric motor 4 is connected through a rheostat 3 and switch 2 to an energy source 1. The motor drives, via transmission gearing 5, 6, 15, 16, a gear-wheel 17. Coaxial with wheel 17 is a sleeve 18 fast with a magnetisable friction disc 21. Sleeve 18 is connected by a key 19 to a shaft 20, but can slide along the shaft, which carries a gear-wheel 23. This engages with a gear 24 fixed to a shaft 25. A solenoid 22 surrounds sleeve 18, and when the solenoid is energized, disc 21 is drawn into frictional engagement with wheel 17, and so turns with it. Thus when the solenoid is energized, driving gear 16 is coupled to drive shaft 25 in the direction A. Fixed to shaft 25 are three cam discs 26, 27, 28 having notches 29, 30, 31, 32 into which contact makers 33, 34, 35 can fall. Shaft 35 also drives a shaft 38 carrying a disc 40 on which is a mark 39 of scythe blade shape. Disc 40 is close to the viewfinder plate 41 of the camera, which carries two fixed marks 44, 45 illuminated by light reflected from lamps 46, 47. The line 0-0 is the optical axis through the objective 42. Also driven from motor 4 is an endless band 14 carrying indicating studs 13, whose velocity is adjustable according to altitude and speed by means of rheostat 3. The switch 2 comprises six interconnected contact arms 50-55, each of which can assume four positions a, b, c, d. The a position is an "off" position. When all switches occupy the b position, switches 53, 54, 55 are still "off", only switches 51 and 52 being in circuit. Consequently cam discs 27, 28 have no effect. The motor is switched on, and if contact maker 33 is riding on the curved surface of cam disc 26, it closes a circuit energizing the solenoid 22, so that shaft 25 is driven round until contact 33 falls into notch 29, so breaking the energizing circuit, so that shaft 25 rotates no longer. While it rotates, switch 58 can be closed to apply a pulse to the camera shutter (direction V) to make a single exposure. When the switches are set in position c, switch arm 52 is still "off" but all the other switch arms operate to close circuits. Switch 53 energizes the solenoid so that shaft 25 rotates once more. Each time contact 34 drops into notch 30 of cam disc 27, as the latter rotates, contact 56 is closed to apply a pulse to the shutter. This process repeats as long as switch position c is maintained, so that a series of exposures is made. The timing of the pulses is indicated by the mark 39 on rotating disc 40, which is coincident with one of marks 44 or 45 each time a pulse occurs. In switch position d, switch arm 55 makes no circuit, so that cam disc 27 has no effect. The closing of switch arm 54 causes cam disc 28 to become effective, a pulse occuring every time contact maker 35 closes contacts 57. Since there are two notches 31, 32 in this disc, the pulses, and hence the exposures, are twice as frequent. In any of the switch positions b, c, or d, a single additional exposure can be made, at any time, in between two consecutive serial exposures, by the operator closing switch 58. Whether he has time to do this is shown by the position of mark 39 relative to marks 44 and 45.