Abstract: Waterproof binoculars of the central focus wheel-type having transfer bars coupled to focussing lens groups within the body tubes, with the transfer bars being simultaneously moved longitudinally by the co-action of a groove on each bar with a flange on a screw-threadingly mounted lead ring turned by a screw-threaded shaft. Each transfer bar is water-tightly sealed in its bore.

Abstract: A waterproof bodytube having a division in its intermediate portion to be used to insert a Porro prism into the binoculars. The construction of this invention is such that a male bodytube having a projection portion is fitted to a female bodytube by means of a packing, and a screw is tightened from its outer surface by means of a packing. For this arrangement, the head of the screw is positioned at the side surface of the bodytube, and this portion is normally covered with a film so that the exposure of the screw can be prevented.

Abstract: A mechanism for longitudinally shifting a shiftable lens group in a zoom lens system, including a lever pivotally mounted in a frame having a rotatable pin on each end thereof, a terminal member mounted on the movable lens group having a groove therein extending perpendicular to the longitudinal axis of the lens system with one of the pins riding in the groove, a shift bar mounted in the frame movable only in parallel with the axis having a groove in one end thereof extending perpendicular to the axis with the other pin of the lever riding in the groove, and a rotatable mechanism in the frame for moving the shift bar longitudinally so that, upon such movement, the engagement of the pin in the groove of the bar pivots the levers so that the engagement of the other pin in the groove of the terminal member shifts the lens group longitudinally.

Abstract: A push button-type mechanism for binoculars which includes a connecting plate having a recessed portion with a bottom and side walls formed in the center portion thereof, the plate at each end thereof being pivotally attached to body tubes having lens frames. A slide frame having inclined surfaces is attached to a lead shaft and positioned in the recessed portion such that one end of the shaft extends slidably through one side wall of the recessed portion. A set of push buttons having shoulder portions and inclined legs are slidably positioned on the inclined surfaces of the slide frame and between the inclined surfaces of the side frame and the perpendicular walls of the recessed portion. A balance spring contacts the shoulder portions of the push buttons. An arm is attached to the extended portion of the lead shaft and the lens frames wherein depression of the buttons causes the lens frames to move to a position of focus on an object being observed.