Lightweight binoculars with good optical properties - has rack and gear focusing device and elastic head band for holding

摘要

The binoculars (1) have three lenses, an objective (2) and two eyepieces (3,3'), arranged in a two part telescopic envelope (4). The objective is fixed in one part (5) while the eyepieces are fixed in the other part (6) so that the principal foci are in the same plane. - An elastic band (15) is end fixed to the eyepiece part. It can surround the head of the user to hold the binoculars at eye height. The binoculars are focused by varying the distance between objective and eyepieces using milled wheels (10) and toothed racks (9) attached to respective telescope parts.