Patent GB-656773-A (GB)
Title: Electric control device for photographic cameras
IPC: G03B9/70
Filed: 1947-07-09
Abstract: 656,773. Photographic cameras. MORLE,C.W. (Kalart Co., Inc.). July 9, 1947, No. 18150. [A Specification was laid open to inspection under Sect. 91 of the Acts, July 9, 1947.] [Class 98 (i)] An electric control device for a camera having a solenoid operated shutter comprises a time switch operated by shutter release means so that the switch energizes the solenoid for a period of time independent of the time for which the release means is actuated. In the form shown in Fig. 2 the shutter release and firing of the flashlight are effected by operation of one of two alternative release buttons connected respectively to cables 65, 66 which pass through holes in an arm 56, carry beads 70, 71 larger than the holes, and are anchored to return springs 57, 57<SP>1</SP>. A pull on either cable thus rotates the arm 56 about its pivot 51, rotating also the arm 50 and the insulating arm 60. In the rest position shown all three contacts 15, 16, 17 are separated. The first rotation of the arm 60 as a result of operation of the release button closes the contacts 15, 16 in a circuit through which may be illuminated the lamp of a range-finder as described in Specification 600,230. Further rotation of the arm 60 opens the contacts 15, and 16, allowing the portion 15<SP>1</SP> of the contact 15 to close on to the contact 17 and complete a circuit through which are fed the shutter operating and flash firing circuits. During rotation of the levers 50, 56, 60 a portion 49 on the lever 50 acts on the lever 48 and rotates it about its pivot 46 against the action of a return spring 47. A toothed sector in the lever 48 engages a pinion 44 to rotate an insulating disc 35 carrying a conducting member over part of its face on which bear three contacts 12, 13, 14. None of these contacts bears on the conducting area when the contacts 15, 17 first close. At the end of the downward movement of the lever 50, however, the lever 48 escapes from under the portion 49 and returns, under the action of its spring, to rotate the disc 35 and the conducting member 11, the leading edge of which is shaped to reach the three contacts 12, 13, 14 at different times. The shutter release circuit is completed through the contacts 13, 14 and the flash lamp firing circuit through the contacts 12, 13. The leading edge of the conducting member 11 is shaped so that the timing of the flash can be altered by angular adjustment of the contact 12 about the pivot 39 through gearing 40, 41. In the embodiment shown in Fig. 4, movement of the release button 169 in an anticlockwise direction about its pivot 177 rotates, through the arm 158, the lever 149 in a clockwise direction about its pivot 150 against a spring 157 to pass and engage under the end of a pivoted arm 135 whose movement is controlled by a retarding device 136. When the end 165 of the lever 149 escapes from the arm 158 the spring 157 returns the arm 149 and throws the arm 135 upwards to engage a contact 134. This supplies current simultaneously to the shutter operating magnet 102 and a flash lamp connected between the sockets 107, 109. Insertion of the lamp connects a pin 113 to the socket 157 to establish a circuit for the lamp 31 of the range-finder which may be completed by contacts 139, 141 in the release button. If a flash lamp is used having a shorter delay than that of the shutter operation it is connected between sockets 107, 108 and its circuit passes through contacts 129, 131 as well as 134, 135. Contacts 129, 131 are opened by movement of the arm 149 before 134, 135 are closed, and are closed again by return movement of the arm while 134, 135 remain closed as a result of the operation of the delay device. The shutter may be operated remotely from the camera by connecting a battery across the sockets 107, 108. In this case if a flash lamp is required to be fired simultaneously it is connected between these same two sockets. Safety switches 52, 53 are included in the circuit and must be closed for the system to operate. Similar switches are used with the embodiment of Fig. 2. One switch is only closed when the cover of the dark slide is removed for exposure as described in Specification 637,461. The other is carried on the lens board of the camera and is closed by the shutter setting arm when in the " set " position. For connections between this switch and the rest of the apparatus on the camera body strips of metal foil may be contained in the bellows walls or the four bellows walls themselves may be of metal with insulating corners.