Improvements in or relating to cameras, particularly television cameras having a lensturret, and control means therefor

摘要

723,872. Lens turrets. PYE, Ltd. April 9, 1952 [April 12, 1951], No. 8625/61. Class 97 (1). [Also in Group XXXVII] A camera lens turret, particularly for a television camera, is rotated, to bring the lenses selectively into operative position, by an electric motor controlled by a manually-operated switch at or remote from the camera, the switch being adjustable to one of a number of positions to complete the motor circuit selectively through one of a number of contact switches operated by the turret so that then the motor has turned the turret to position the selected lens, the turret operates the selected contact switch to stop the motor. The system may be so arranged that the direction of rotation of the turret varies according to the lens selected. As shown the turret K carries lenses 1, 2, 3 and 4 and a cam J engaging one of four contacts E1, E2, E3, E4 appropriate to each lens and connected to an electric supply N1, N2 and a motor M for rotating the turret, through switches controlled by relays R1, R2, R3, which are respectively responsive to different voltages. The relays are controlled by a switch D at the camera or by a switch D1 remote from the camera and connected thereto by suitable cable B, Operation is as follows. If it is desired to substitute lens 2 for lens 1 in the operative position C the arm of the switch D is moved to contact D2. This causes a certain voltage to be applied to the relays through resistances F and G, the voltage being sufficient to operate relay R1 but insufficient to operate the relays R2, R3. Relay R1 closes the motor circuit through switch E2, the turret turning until the lens 2 reaches the position C whereat the cam J operates switch E2 to open the motor circuit. The circuit operates similarly for other positions of the switch D except the position D1 in which none of the relays is operated, the circuit being then completed through the switch E1. Remote operation from the switch D1 is similar, a series of relays R1SP1/SP, R2SP1/SP, R3SP1/SP being additionally provided at the remote station to operate one of the lamps L1-L4 indicating the operative lens. In a modification each switch E1-E4 is arranged to be reversing, i.e. to have three positions, and a suitable cam is provided on the turret so that if selection of the lens immediately preceding the lens in use in the usual direction of rotation of the turret is effected, the motor M is reversed to position that lens. In this modification the selector switch D at the camera is replaced by a series of push-buttons.