| 摘要 |
An electrically driven automatic film advance camera with automatic transition to rewind without external actuation is described. Film advance after each exposure occurs automatically after release of the shutter actuating button by means of an integral electric drive motor preferably contained within the film take-up spool. The end of film condition during film advance is signalled by a sudden onset in film tension, which actuates a switching system to reverse motor drive polarity and power the motor until the film is completely rewound into the cassette, whereupon motor actuation ceases. A take-up spool gear drive train remains fully engaged at all times. During the rewind operation both the take-up spool and the drive spool are driven simultaneously by the drive motor to facilitate film disengagement. A film engaging sprocket serves to govern film advance for framing purposes, the sprocket being principally in an idling state throughout the film advance operation. An auto-loading feature is provided in the form of an engaging hook on the film take-up spool, whereby during the loading operation the film advance mechanism actuated once to cause film capture by the take-up spool. Threading of the take-up spool is thereby totally eliminated. A transitional propulsive assist to the film capture operation is provided. A large take-up spool is employed, and the drive motor placed therein, resulting in a significant saving of space. |
