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US 4,021,828 AGranted
Film counter
AssigneeCanon Kabushiki Kaisha
InventorsYukio Iura, Masayoshi Yamamichi, Takashi Uchiyama, Tetsuya Taguchi, Yukio Mashimo
Life of this patent
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Abstract
An electrical film counter for a photographic camera is provided with a differentiating circuit responsive to a film winding operation for producing an output pulse. The number of output pulses from the differentiating circuit is counted by an UP-DOWN counter and is decoded by a decoder designed to drive an indicator which indicates the number of film frames advanced through the film gate of the camera.
Claims14
An electrical film counter comprising a camera having a film transport mechanism and an openable back cover, and arranged to have a film cartridge inserted thereinto:
- pulse generating means cooperable with said film transport mechanism to generate one pulse responsive to each advance of the film in said camera by one frame;
- a first pulse counter having an input connected to said pulse generating means and operable to count the pulses from said pulse generating means;
- film frame indicating means connected to said first pulse counter and operable to indicate the number of film frame corresponding to the content of said first pulse counter;
- a source of electric potential;
- and
- first switching means placed in an "on" state responsive to closing of said back cover and placed in an "off" state responsive to opening of said back cover, said first switching means being connected between a source of electric potential and a power supply terminal of said first pulse counter to enable said first pulse counter to operate.
3 more elements
An electrical film counter comprising:
- a camera having a film transport mechanism and a back cover;
- pulse generating means cooperable with said film transport mechanism to generate one pulse response to each advance of the film by one frame;
- a first pulse counter having an input connected to said pulse generating means and a clearing terminal and operable to count the pulses generated by said pulse generating means;
- film frame indicating means connected to said first pulse counter and operable to indicate the number of film frames corresponding to the content of said first pulse counter;
- and switching means connected to said clearing terminal of said first pulse counter and operable, responsive to the opening of said back cover of the camera, to apply a clearing signal to said first pulse counter.
2 more elements
An electrical film counter comprising:
- a camera having a film transport mechanism;
- pulse generating means cooperable with said film transport mechanism to generate one pulse response to each advance of the film by one frame;
- a first pulse counter having an input connected to said pulse generating means and operable to count in the pulses generated by said pulse generating means;
- film frame indicating means connected to said first pulse counter and operable to indicate the number of film frames corresponding to the content of said first pulse counter;
- a source of electric potential;
- and first switching means placed in an "on" state responsive to a preparatory operation of the camera for photographing and placed into an "off" state responsive to a photographing terminating operation, said first switching means being connected between said source of potential and a power supply terminal of said first pulse counter to enable said first pulse counter to operate;
- said first pulse counter being an UP-DOWN counter having presetting terminal means.
4 more elements
An electrical film counter comprising:
- a camera having a film transport mechanism;
- pulse generating means cooperable with said film transport mechanism to generate one pulse responsive to each advance of the film in said camera by one frame;
- a first pulse counter having an input connected to said pulse generating means and operable to count the pulses from said pulse generating means;
- film frame indicating means connected to said first pulse counter and operable to indicate the number of film frames corresponding to the content of said first pulse counter;
- a second pulse counter connected to said pulse generating means and operable to count the number of pulses from said pulse generating means, said second pulse counter having an output terminal;
- a flip-flop circuit having a set input terminal and an output terminal;
- connecting means connecting the output terminal of said second pulse counter to the set input terminal of said flip-flop circuit;
- and an AND gate having a first input terminal connected to the output terminal of said flip-flop circuit and a second input terminal connected to the output terminal of said pulse generating means, said AND gate having one output terminal connected to the input terminal of said first pulse counter.
5 more elements
Dependencies are inferred from the claim text.