GB525970A - Improvements in or relating to microscopes - Google Patents

Abstract

525,970. Microscopes. COOKE. TROUGHTON & SIMMS, Ltd., and TAYLOR, E. W. March 3, 1939, No. 7090. [Class 97 (i)] A microscope is provided with a ball-bearing slideway comprising a pair of outer members and a member disposed between them having on each side a single guideway facing one on the adjacent outer member, balls or groups of balls being located in each pair of facing guideways. Adjusting means comprise an involute cam which engages and lifts an appropriatelyshaped element through a distance having a linear relation to the movement given to the cam. The microscope shown comprises a coarse motion sliding block 3 which is adjusted by a rack-and-pinion operated by the heads 6 and houses the fine motion adjusting means. The fine motion slide block 9, which carries the objective nose-piece by means of a bracket 10, is of T-section, a ball-bearing groove being formed on each side of the web 9a opposite to a similar groove in one of a pair of vertically disposed plates 8 secured to the front of the block 3. The groups of three balls 13 are arranged in cages between the grooves. The web 9a is split so that it may be expanded to adjust the ball guides in relation to one another by means of grub screws 17 accessible through holes closed by screws 19 in the block 3. The fine adjustment mechanism comprises an arm 23 movable about its pivot 24 by a sector and worm 27, 28, and carrying an involute cam 22 which engages the underface of a block 21 carried by an arm 20 secured to the slide block 9. A spring 34, housed in a hole bored in the web 9a forces the slide downwardly, the pressure so produced by the block 21 on the cam 22 taking up back-lash in the sector and worm drive 27, 28. The microscope body 4 is interchangeably and adjustably attached to the coarse motion block 3 by a dovetail slide and clamp ; alternatively, it may be carried by the fine motion slide. The fine cam-operated adjustment means described may be replaced by a rack and pinion. The ball-bearing slideway may be applied to the coarse motion slide block, and both it and the cam operated adjusting mechanism may be applied to the stage carrying the specimen. Specification 467,926 is referred to.