Patent GB-1259238-A (GB)
IPC: G03B19/04
Filed: 1970-04-29
Abstract: 1,259,238. Electrically operated cameras. CANON K.K. April 29, 1970 [April 30, 1969], No. 20592/70. Heading G2A. A camera has two electric motors M 1  and M 2 , for winding on the film and operating the shutter respectively, and control means for starting one motor and stopping the other so that they work in alternation. The arrangement can provide single or successive frame photography, either manually or by remote control. As shown, the drive from motor M 1  is transmitted by a gear train to a pulley 6 and thence by a belt 7 to a disc 10 having pins 10<SP>1</SP> which engage the film winding means of the camera. Belt 7 passes over a pulley 17 at one end of a V-shaped lever 19 which is biased clockwise about a pivot 18 by a spring 20. The drive from motor M 2  is transmitted via a worm gear 22 to a wheel 23 which has fixed pins 25, 26 on opposite sides thereof. The control means is a sliding bar 36, and is shown in Fig. 1 as being retained against leftward movement under the action of a spring 45 by engagement of a hooked end 19b of lever 19 with a stepped portion 36a of the slider 36. This is the position during film wind by motor M 1 , and in the arrangement for a single-frame exposure. A pin 42 on slider 36 engages and closes a switch S 1 . A further manually operated switch S 3  is in the full-line position, and a switch S 4  is open. Thus the motor M 1  is in circuit with the battery E. When the film wind has been completed, the movement of wheel 10 is arrested, and so the tension along the side 7a of belt 7 is increased. Thus the end 19a of lever 19 is drawn downwards and the other end 19b disengages from slider 36. This is now free to move to the left, during which movement pin 42 releases switch S 1  to open so that motor M 1  stops, and closes another switch S 2 . The device is now ready to make an exposure. Switch S 3  is changed over from its full-line to its broken-line position. Since switch S 2  is now closed, motor M 2  is in circuit with the battery and begins operating, turning wheel 23 clockwise. Wheel 23 has previously been locked by engagement of the end 38a of a lever 38 under pin 26, but movement of slider 36 to the left has allowed a spring 38c to pivot the lever free of pin 26. As wheel 23 turns, pin 25 engages against one end of a lever 28 whose other end pushes the release pin 27 upwards and so actuates the camera shutter. Continued rotation of wheel 23 brings pin 25 into engagement with one end of a lever 32 and pivots it anti-clockwise. The other end of the lever engages a pin 40 on slider 36 and so pushes the slider to the right, back into the Fig. 1 position, so opening switch S 2  and closing switch S 1  once more. Thus motor M 2  is shut off, but continues to rotate wheel 23 because of its inertia until it is stopped by pin 26 abutting against the end of lever 38. When switch S 3  is released, it returns to its full-line position, so energizing the M 1  circuit and winding on the film as described above. This concludes the operating cycle, with the shutter ready to be released. If switch S 4 , in parallel with switch S 3 , is closed, motor M 1  begins to operate immediately motor M 2  stops even though switch S 3  is not changed over, so that the cycle of shutter release and film wind repeats continuously. Fig. 2 (not shown) is a modified arrangement in which the drive from the motor M 1  is transmitted to the film winding disc 10 by a torsion bar arrangement instead of by a belt. Fig. 5 (not shown) is a circuit including a delay section for delaying the start of the shutter release motor M 2 , and a timer section for changing the intervals between successive exposures, the circuit being adapted for remote control by an extension cable. Indicator lamps may be provided for showing which motor is operating. The device of the invention may be built into a camera, or constructed as a separate detachable unit.