Film wind-up arrangement for motion-picture cameras

In a motion-picture camera, in combination, a prime mover, a film wind-up member, and a torque-equalizing clutch arrangement coupling the film wind-up member to the prime mover for transmitting torque to the latter, the clutch arrangement comprising automatic wind-up torque regulating means operative for continually maintaining the wind-up torque transmitted to and exerted by the film wind-up member substantially constant at a preselected value throughout the whole film wind-up operation by automatically disengaging the clutch arrangement when the wind-up torque begins to exceed the preselected value and automatically reengaging the clutch arrangement when the wind-up torque then begins to fall below the preselected value, so as to establish transmission of an intermittent wind-up torque having an average value which is substantially constant and equal to the preselected value, the wind-up torque regulating means including a rotary driving part driven by the prime mover, a rotary driven part driven by the driving part and driving the film wind-up member, the driving part being movable between a first position in which it receives torque from the prime mover and a second position in which it is disengaged from the prime mover, the driven part being arranged to urge the driving part toward the second position thereof with a force which increases with increasing wind-up torque, and biasing means for urging the driving member to the first position thereof with a predetermined force which is overcome by the driven member when the wind-up torque begins to exceed the preselected value.