GB430826A - Improvements in or connected with encased optical observation instruments and the transmission of motion from the outside of the casing to parts within the casing - Google Patents

Abstract

430,826. Optical observatiom instruments. BARR & STROUD, Ltd., and STRANG, J. M., Caxton Street, Anniesland, Glasgow. Dec. 23, 1933, No. 36223. [Class 97 (i)] A part of an encased optical observation in. strument, e.g. a telescope, binoculars, rangefinder, height-finder, or periscope, is movable by magnet action exercised from outside the casing by a control element movable by hand. The control element may be a permanent magnet or electromagnet ordinarily remaining attached to the casing or alternatively may be detached and applied to the casing when desired. Soft iron pieces may be provided in the casing to assist the magnet action. The casing of a telescope may be provided with a rotatable annular control ring which carries two semicircular magnets and is concentric with a rotatable disc pivoted inside the casing. The disc carries a number of filters for alternative use and an armature to co-operate with the magnets on the control element. In a modification the filter disc may have peripheral teeth engaging a pinion the spindle of which carries an armature co-operating with a rotatable control ring outside the casing. Fig. 8 shows a lens carrier E which is moved axially for focusing by screw action in a casing D. A rotatable control ring C<2> on the casing D carries a magnet 18 co-operating with an armature 17 on the carrier E. A control ring movable longitudinally on the outside of the tubular casing of a rangefinder may be used to move the carrier of refracting prisms inside the casing along longitudinal guides. The control element may be used to release locking members.