| 摘要 |
PURPOSE:To decrease the number of components and to simplify a constitution by extending a photographic lens and operating a shutter with the driving force of one electromagnet driving mechanism. CONSTITUTION:The electromagnetic coil 10 of an electromagnet 8 is fed with a pulse train current consisting of a positive-negative pulse train which is invert ed in polarity successively before the photographic lens reaches its focusing point, and a pendulum lever 1 repeats reciprocal motion about a supporting shaft 2 as a fulcrum according to the driving torque of permanent magnets 4 and 5. A feed claw 14 moves forth and back repeatedly according to the reciprocal motion of the lever 1 to feed a ratchet gear 16, teeth by teeth, and extend the photographic lens. When the photographic lens is extended to a focusing position, the lever 1 rotates to the position in a figure and a magnet 7 contacts an armature 27 and is fed electrically. At this point the magnet 7 attracts the armature 27 to couple a shutter opening/closing lever 22 with the lever 1. At this stage of the operation, the lever 22 is associated with the forward motion of the lever 1 to open a shutter blade 23. |
