ELECTRIC CAMERA SHUTTER WITH MANUAL CONTROLS

• US 3,820,125 A
• Filed: 05/09/1972
• Issued: 06/25/1974
• Est. Priority Date: 05/19/1971
• Status: Expired due to Term

• Current Assignee: Seinan Miyakawa
• Original Assignee: Seinan Miyakawa
• Inventors: Miyakawa, Seinan
• Primary Examiner(s): Sheer, Richard M.
• Assistant Examiner(s): Gellner, Michael L.
• Application Number:
  US05/251,763
• Time in Patent Office: 777 Days
• Field of Search: 95/1CT
• US Class Current: 396/252
• CPC Class Codes: G03B 7/003 setting of both shutter and diaphragm G03B7/02 - G03B7/22 take precedence
• CPC Class Codes: G03B 7/083 for control of exposure time
• CPC Class Codes: G03B 9/58 Means for varying duration of "open" period of shutter

Abstract

A camera capable of determining exposure either manually or automatically. Thus, the camera has circuitry for automatically determining the extent to which film in the camera is exposed, and this circuitry is adapted to receive signals corresponding to exposure-determining factors. A pair of signal-transmitting assemblies are provided for transmitting the signals to the circuitry, and one of these assemblies provides signals according to the lighting conditions while the other provides a manually selected signal. A switch is capable of connecting either of these assemblies to the circuitry so that it becomes possible while utilizing the same circuitry to determine the extent of exposure either automatically in response to various exposuredetermining factors or in response to a manually selected signal which is then introduced into the circuitry which then operates in exactly the same way for automatically determining the exposure.

Claims

1. In a camera having circuitry for automatically determining the extent to which film the camera is exposed, electromagnetic means for terminating an exposure, switching circuit means electrically connected with said electromagnetic means for controlling the latter, signal-transmission means electrically connected to said switching circuit means for transmitting to the latter signals according to exposure-determining factors, said signal-transmission means including a capacitor, automatic signal supply means and manual signal supply means for respectively supplying automatic and manually determined signals to said signal-transmission means, said automatic signal supply means providing a signal in the form of a voltage the magnitude of which is automatically determined according to the lighting conditions at the object to be photographed and said manual signal-supply means providing a manually determined signal in the form of a voltage the magnitude of which is manually determined, and both of said signal supply means operating simultaneously to render both of said voltages simultaneously available, and selecting switch means electrically connected between said capacitor of said signal-transmission means and said automatic and manual signal-supply means for selectively connecting one of said signal supply means to said signal transmission means for charging the capacitor thereof with the signal voltage provided by the selected signal supply means while the non-selected signal voltage supplied by the other of said signal-supply means remains present and available for selection, said manual signal-supply means being in the form of a circuit which is completely independent of the other circuitry except for a ground connection in common therewith, which has its own power source, and which is electrically connected only with said selecting switch means to be selectively placed thereby in electrical cooperation with said signa-transmission means, all of said other circuitry having a power source different from that of said manual signal-supply means so that when the latter is placed by said selecting switch means in electrical connection with said signal-transmission means, the signal from said manual signal-supply means influences the operation of said signal-transmission means with the latter remaining connected independently of said manual signal supply means to the power source of the other circuitry which is independent of said manual signAl-supply means.

2. The combination of claim 1 and wherein said manual signal-supply means includes a manually operable variable resistor means for manually determining a selected exposure time.

3. The combination of claim 1 and wherein said selecting switch means includes a pair of contacts, one of which is electrically connected with said automatic signal-supply means and the other of which is electrically connected with said manual signal-supply means, and a switch member to be selectively placed in engagement with a selected contact, said manual signal-supply means being electrically connected only with said other contact and said common ground connection so that when said switch member of said selecting switch means engages said one contact said manual signal-supply means is connected only to the common ground connection.