GB904280A - Improvements in or relating to mountings for optical lens assemblies - Google Patents

Abstract

904,280. Lens mountings; microscopes. COOKE, TROUGHTON & SIMMS Ltd. Oct. 13, 1960 [Oct. 20, 1959], No. 35512/59. Class 97 (1). An optical lens assembly mounting includes a first cantilever arm carried by a shaft supported in the mounting, at least one lens element arranged at the free arm end with the optical axis thereof parallel to the shaft axis, means for pivoting the arm about the shaft axis to displace the element into and out of a required optical path, and further means for displacing the arm axially of the shaft so as to displace the element along its optical axis. The invention is described as applied to a projection microscope and as shown, the mounting incorporates a corrector lens assembly 1 and a projection eyepiece assembly 2, which can be selectively interposed in the light path. The mount 6 of the lens assembly 1 is carried by a cantilever arm 7 which is fast on an arm 8 parallel to the optical axis and journalled in a mounting 5. The lens assembly 2 includes a central lens 12 carried by an arm 11 attached to a cylindrical rack 9, which is freely rotatable around and slidable on the shaft 8, the lens 12 being disposed between lenses 15, 16 in a mount 14 which is carried by an arm 13 fast with the shaft 8. Relative angular movement of the arms 10, 13 is prevented by grub screws which pass through the arm 10 and maintain contact with the arm 13. Pivoted to the arm 7 is a yoke 19 to which is attached an auxiliary slidable push rod 20, movement of which brings either or none of the lens assemblies 1, 2 in the light path. Focusing movement of the central lens 12 of the projection lens assembly 2 is effected by rotation of a pinion 27 which engages the cylindrical rack 9. This pinion 27 is mounted on a shaft 28 attached to a drum 30 between which and a central drum 36 is a friction ring 39 acting as a slipping clutch. There is also provided a fixed drum 31 and a drum 33 which is rotatable into any one of three positions corresponding to the magnification set in a magnification chamber within the microscope. In operation, the magnification of the microscope objective, as read on the end portion 38 of the drum 36, is set against an index on the drum 30, the index on drum 33 is then set against the appropriate magnification changer value on the fixed drum 31, drums 30, 36 are rotated together to form lens 12, whereupon the final image magnification can be read from the end portion 37 of the drum 36 as it appears against another index on the drum 33.