| 摘要 |
1,155,790. Linkwork. BELL & HOWELL CO. 1 June, 1967 [21 July, 1966], No. 25430/67. Heading F2Q. [Also in Division G2] A zoom lens assembly 55 is mounted within a ring 41 which is given stepwise rotation by a surrounding friction band 75 whose ends 79 are attached to the legs 121 of a link 109 which is mounted on an eccentric 105 secured to a shaft 85 of a driving motor 83. An adjustable pivot pin 125 is located between the legs 121 of link 109. The motion given to the link 109 by the eccentric 105 causes tension of the band 75 to be cyclically increased and relaxed, the ring 41 being given a partial rotation during the periods of tension. The ring 41 may be driven in the reverse direction by changing the direction of rotation of driving shaft 85. At the limits of rotation of the ring 41, the friction band 75 slips. Also the link 109 is made of flexible plastic material so that it will bend or yield on overload. Cam mechanism converts rotation of ring 41 into axial movements of the lens assembly. |
