GB1456165A - - Google Patents

Abstract

1456165 Electronic control of cameras FRANKE & HEIDECKE GmbH [trading as ROLLEI-WERKE FRANKE & HEIDECKE] 17 Oct 1974 [6 Nov 1973] 45026/74 Heading G2A A camera has an electronic control arrangement which includes a stepping switch actuated by an impulse generator, the switch setting up in succession the various camera functions involved in making an exposure, and in one stage of the stepping switch movement the film transport motor is switched on, and then is switched off again after film transport has been effected. As shown, the film winds off a spool 12, passes between a gate 13 and pressure plate 24, round a cog-wheel 22 whose teeth 22a engage in the film perforations, and is taken up on a spool 11 which is driven by a motor 9 via a cog-wheel 10'. The stepping switch 15 is actuated by the impulse generator 16 in such a way that on each impulse the switch emits a signal to one of its outputs 17, in a fixed order of succession, to operate such camera functions as raising or lowering the mirror in a reflex camera, setting the diaphragm, and opening and closing the shutter. The film stepping unit 7 is connected to the electric control section 5 by leads 6, and inside the unit 7 the lead 6 is interrupted by a film scanning contact 18 and a pair of contact springs 19a, 19b. These springs can be inter-connected by an electrically conductive contact path 20 mounted on a disc 21 which is driven by cog-wheel 22. Contact 18 is opened when the camera housing is opened to insert or remove the film. When film is inserted, and the housing closed, contact 18 is closed. A transistor circuit is connected with a particular output 17 of stepping switch 15, so that when the switch reaches this stage, the gap between contacts 19a, 19b is bridged, and the motor 9 is energized, so driving spool 11 to transport the film. This in turn drives cog-wheel 22 and hence disc 21. Thus, as the stepping switch moves on to another output stage, and the transistor is blocked, the contacts 19a, 19b remain connected by path 20, and the motor remains operative, continuing to drive the film, until the contacts reach the gap between two sectors of path 20. The motor circuit is thus interrupted, and film transport ceases. The conductor path 20 is so designed that exactly one frame of film is transported. In the arrangement of Fig. 5 (not shown), a counter device is incorporated, and the motor may be switched off automatically after a predetermined number of film frames (e.g. 12 or 24) have been wound on.