GB762739A - Improvements relating to clockwork mechanism for driving a film camera - Google Patents

Abstract

762,739. Clockwork mechanisms. STEATITMAGNESIA AKT.-GES. Nov. 18, 1954, No. 33456/54. Class 10. [Also in Group XXIV] In a clockwork mechanism for driving a film camera comprising a driving transmission gearing and a driving spring which can be wound by pulling a flexible element secured to a rotatable drum against the action of a return spring the means for winding the driving spring comprises a winding transmission gearing and a silent ratchet gear in the form of a pawl secured to the drum and engaging with a notched wheel connected with the winding transmission gearing, the driving transmission gearing being automatically disconnected from the driving spring during winding by an automatic clutch device. The clockwork mechanism shown comprises winding tape and drum 9, 13, the latter being freely rotatable about a stationary spindle 15 upon which is also mounted in a freely rotatable manner a hub carrying a notched wheel 14 and a gear-wheel 10. Rotation of this gear-wheel effects through wheels 11, 12, 28 winding of the driving spring 6 within the barrel 7. A pawl 17 is pivotally mounted on the drum 13 and during " winding '' rotation of the latter is held in engagement with a notch of the wheel 14 by a hairpin spring 16 which is so mounted on the spindle 15 that relative angular movement between the spring 16 and the spindle is made difficult. The tape 9 is re-wound on the drum through the action of a return spring therein, the outer end of the spring 16 holding the pawl 17 out of engagement with the wheel 14 during this re-winding. The drive to the camera from the wheel 28 is effected through a coiled spring one-way clutch which comprises two pinions 18, 19, with respective hubs 20, 21, freely mounted on a spindle 23 and connected by a helical spring 22 such that the latter is tightened about the hubs on rotation of the spring barrel in the direction opposite to the arrow shown thereon to thus establish a positive connection between the pinions 18, 19, and is loosened about the hubs on rotation of the spring barrel 7 in the winding direction.