Still-camera film transport system with end-of-film motor deenergization

US4196993A · kind A · utility

Assignee

• AGFA-Gervaert AG · DE

Inventors

• Otto Stemme · Munich, DE
• Peter Lermann · Feldkirchen-Westerham, DE
• Karl Wagner · Munich, DE
• Dieter Engelsmann · Unterhaching, DE
• Rolf Schroder · Wuppertal, DE

Key dates

• Filing date: Oct 26, 1978
• Grant date: Apr 8, 1980
• Expiry date: Oct 26, 1998

Classification

• Technology area (CPC G): Physics
• CPC primary: G03B1/16
• WIPO field: Optics
• WIPO sector: Instruments

Abstract

A still-camera film transport system includes a perforation feeler and cooperating perforation-detecting switch generating a perforation signal. A time-delay circuit initiates a time delay upon the commencement of film transport and generates a time-delay-elapsed signal when the time delay has elapsed. The duration of the delay is greater than the time required for the film transport motor to transport film from the last film perforation to the actual end of the film. A shutter-state switch generates a signal indicating whether the shutter is in set or unset state. A motor-control switch is controlled from the output of a logic-circuit stage which receives the above three signals. During normal operation before the last perforation is passed, the perforation signal is used to generate a deenergize-motor signal, but in dependence upon the shutter-state signal. When the last film perforation is passed, another perforation signal will not be generated, but after the elapse of the predetermined time interval, the time-delay-elapsed signal causes the film transport motor to be deenergized, but not before the actual end of the film has been reached.