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:
Oct. 05, 1976
Filed:
Mar. 03, 1975
Bruce K Johnson, Andover, MA (US);
David E Van Allen, Malden, MA (US);
Polaroid Corporation, Cambridge, MA (US);
Abstract
An exposure counter for use in a camera which provides a user with information as to the number of remaining exposures within a film cassette positioned therein. The exposure counter includes a drum or cylinder which is coupled to one member of a gear train which operates to simultaneously index the drum and actuate a film-advancing apparatus so that the drum is sequentially indexed to change a character present at a counter window in the camera while the film-advancing apparatus operates to advance an exposed film unit from within the cassette to the exterior of the camera. The camera is provided with a pawl which, when held in its operative position by the cassette, functions to allow rotation of the drum from a starting position to a terminal position while simultaneously preventing rotation of the drum back to its starting position. Upon removal of the cassette from within the camera, the pawl releases the drum thereby permitting it to be reset automatically to a starting position whereat the drum presents an appropriate character to the counter window which is subsequently changed upon the proper positioning of a new film laden cassette within the camera and for each subsequent exposure.