Automatic film rewinding device
AssigneeCanon Kabushiki Kaisha
InventorsTateo Yamada, Hiroyuki Kimura, Hideo Taka
Life of this patent
Estimating the term…
Abstract
In an apparatus such as a camera which automatically performs film winding and rewinding by means of a motor, an automatic rewinding circuit is arranged to detect interruption of a winding action by means of a timer circuit which is set at a length of time longer than a predetermined length of winding time. Upon detection of the interruption, the automatic rewinding circuit automatically shifts the winding action to a rewinding action. The apparatus is also provided with a memory storage which mechanically memorizes the operating state of the automatic rewinding circuit or with a forced rewinding device which permits a rewinding operation irrespective of the operating state of the automatic rewinding circuit.
Claims15
An automatic film rewinding device for a camera, comprising:
- (a) winding means for automatically winding a film;
- (b) rewinding means for automatically rewinding the film;
- (c) an automatic reversing circuit which electrically detects the end of the film winding operation of said winding means when said film comes to the end of the roll and actuates said rewinding means;
- and
- (d) mechanical memory means for mechanically memorizing that the film is under a rewinding operation, said memory means being arranged to cause said rewinding means to perform the rewinding operation until completion thereof.
A camera which can perform automatic winding and rewinding of film, comprising:
- (A) a spool for taking up the film;
- (B) electric winding means for driving said spool to perform a winding operation;
- (C) a sprocket which is rotated by movement of the film as said film is taken up by said spool;
- (D) control means for effecting windup of one frame of film and for detecting the amount of movement of the film in response to rotation of said sprocket and for stopping said electric winding means when said control means detects that one frame of the film has been wound;
- (E) electric rewinding means for carrying out rewinding of the film;
- (F) timer means for controlling said electric rewinding means to perform the rewinding operation after elapse of a length of time commencing from the start of the one frame winding operation by the electric winding means which is longer than the period of time required by said electric winding means for windup of one film frame, said timer means operating so as to not have said electric rewinding means carry out the rewinding operation before said length of time has elapsed;
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- (G) rewinding prohibition means disabling said timer means from functioning when said control means for the winding of one frame detects the completion of said one frame windup of the film within the period of time the electric winding means requires for the completion of one frame winding.
Dependencies are inferred from the claim text.