The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 02, 1980
Filed:
Aug. 29, 1979
Masanori Uchidoi, Yokohama, JP;
Masaharu Kawamura, Kawasaki, JP;
Yoshihiro Shigeta, Tokyo, JP;
Yoji Sugiura, Yokohama, JP;
Hiroshi Yamamoto, Yokohama, JP;
Nobuo Tezuka, Tokyo, JP;
Canon Kabushiki Kaisha, Tokyo, JP;
Abstract
A safety device for preventing non exposure of film in a camera having a count switch which is normally closed prior to shutter release operation, the switch being opened after the shutter release operation begins to enable a timing circuit to start operating. In a preferred embodiment, the device includes a NOR gate having an input connected to one side of the count switch, and its output connected to the set terminal of a flip-flop which enables the shutter release operation. Another input of the NOR gate is connected to a differentiation circuit which provides an output signal when the shutter release button on the camera is actuated. This circuit arrangement operates so that the flip-flop is not set if the count switch is accidently in an open state when the release button is actuated. The shutter release operation is thereby prevented until the count switch is restored to working order.