GB588137A - Improvements in or connected with vibration damping mountings for optical observation instruments - Google Patents

Abstract

588,137. Mounting range-finders &c. BARR & STROUD, Ltd., FRENCH, J. W., STRANG, J. M., and MACGILL, C. D. April 30, 1943, No. 6851. [Class 97 (i)] [Also in Group XXXII] An anti-vibration mounting for an optical observation instrument such as a range-finder comprises a plurality of resilient supporting elements, e.g. metallic springs, which are not of self-damping character, and which provide support for the instrument at a normally horizontal plane through the centre of gravity of the instrument, and, in association therewith, one or more damping devices of dashpot character. Elastic self-damping material may be used in addition to the resilient supporting elements. As shown in Fig. 1, each element consists of a helical spring A and a vibrationdamper B such as described in Specification 502,535 comprising a liquid-filled bellows chamber B <1> secured to the supporting structure E 'and a rigid chamber B<2> separated by a partition C secured to the supported structure and containing a passage 1 for liquid regulatable by a screw valve 2. In a modification, both chambers are of bellows construction. Transverse movement may be restricted' by further springs arranged in other planes. The spring A may be arranged on one side of the damper B. Fig. 5 shows another construction of element in which a steel ball 10 separates a cup 12 on each end of a semi-elliptical spring M from a cup 11 secured to the supporting structure E, the balls providing for lateral yield. In a modification, the spring M is replaced by a leaf spring having three radial arms. In a further construction, Fig. 3, the dashpot is of the piston-and-cylinder type, the piston-rod 8 being tiltable laterally and centred by a spiral spring 9, while the spring-supported piston 5 is apertured for passage of liquid. In other constructions of dashpot: (a) damping is effected by the provision of a clearance space between the piston and cylinder, the piston-rod having a spherical top end engaging a seating in the supported structure while a corrugated flexible annular member, e.g. of rubber, is fitted to the top of the cylinder and bears against the supported structure ; (b) the piston 44, Fig. 12, has upper and lower piston-rods 45, 46, the rod 45 having a universal connection 47 with a rod 48 ball-jointed at 49 to a seating D ; (c) the piston, containing a passage for oil, has upward and downward extensions passing through glands in the cylinder to equalize resistance to movement of the piston in both directions, while the piston-rod has spherical ends engaging the piston and a seating on the' supported structure ; (d) the cylinder T, Fig. 11, is formed within a ball 34, a hemispherical cover 39 secured to which has a. part-spherical top 41 engaging the seating 42, while the apertured piston 35 has rods 36, 37, the lower rod 37 being anchored to the supporting structure E.