This invention relates generally to camera shutters and more particular to a shutter blade rebound preventive device for a camera shutter.
Generally speaking, camera shutters are constructed such that the shutter driving levers, placed in the shutter cocking position, are operated to the shutter opening and closing position by a spring force during the progress of the shutter release operation. But these known constructions have a fault in that in opening and closing the shutter the driving levers collide with their stop position and rebound causing non-uniformity of exposure and reexposure because of the rebound of the shutter blades interlocked therewith.
In order to prevent this phenomenon, formerly the following means have been proposed: a means to prevent the rebound of the driving lever by providing it with a rebound preventive device which has a concave cam part and by receiving in the above cam part a pin of the driving lever flipped to the opening and closing position or a means to absorb the rebound force of the driving lever by developing friction preventing rebounding by use of a friction piece on the driving lever. But in the former means the cam of the rebound preventive lever might prevent oscillation of the shutter driving lever in case of a rapid cocking operation. This becomes a serious shortcoming, for instance, for a camera of which high speed photography is demanded. In order to secure operation of the rebound preventive lever it is necessary to make quite strong its spring force, but when the spring force is made stronger in the former means, it is undesirable since the load in the case of the driving lever disengaging from the cam part in the cocking operation directly affects a smooth operation in cocking the shutter. In the latter case the shutter not only lacked durability, but also had the shortcoming that the stop position of the driving lever became so unstable that operation became uncertain and the charging or cocking operation became heavy.
USPTO Backgrounds
USPTO Backgrounds