Abstract: A backlash-free drive for the infeed mechanism of a microtome, comprising a threaded spindle (1) mounted so as to be rotatable but axially non-shiftable, as well as two nut elements (2a, 2b) connected such that they are non-rotatable but can be shifted in an axial direction relative one another, said nut elements being spring-loaded against one another in an axial direction. Acceptable tolerances for the conicity of the threaded spindle are obtained by making use of at least one plain bearing (11,13;12,14) between the threaded spindle and nut element (2a), said nut element being connected to a specimen holder (16) via a gear. Fences (30,32;31,33) acting in the direction of spindle rotation protect the thread from deformation, as do two frictional clutches (24;25), which prevent excessive driving torques from having an effect and allow the user the option of operating the micrometer with manual feed (22) or an automatic feed device (26).

Abstract: A guide device for guiding a movable part of an apparatus relative to a fixed part of the apparatus, includes a first guide rail adapted to be provided on the movable part and a second guide rail adapted to be provided on the fixed part. Bearing means comprising a plurality of roller elements disposed in a roller support is disposed in a longitudinal groove between the first and second guides and movable relative thereto. Biasing means is provided which biases the bearing means toward a predetermined position.

Abstract: A specimen holder clamp for a microtome comprising a fixed jaw which is fixed relative to a guide member and a movable jaw which is movable along a path defined by the guide member. The clamp is provided with a first infinitely adjustable rack, and the movable jaw carries a second complementary incrementally adjustable rack for coupling engagement so that when the second complementary incrementally adjustable rack engages with the first infinitely adjustable rack, fine adjustment of the clamp can be effected, and when the second complementary incrementally adjustable rack is disengaged, coarse adjustment can be effected. The second complementary incrementally adjustable rack is normally biased into engagement with the first infinitely adjustable rack.

Abstract: A microtome has a specimen holder which executes a vertical up and down movement relative to a cutting knife and which has a guide mechanism in which a sleeve is arranged so as to be horizontally displaceable. The sleeve is provided at its front end with a specimen clamping mechanism and in its interior with a micrometer nut which is secured against axial displacement and through which extends a micrometer spindle mounted on the guide mechanism. The micrometer nut has on its outer face a toothed ring which is connected operatively to a pinion connected to an electric motor. When the electric motor is activated the sleeve is displaced in the guide mechanism. The micrometer spindle extends, on the side opposite the specimen clamping mechanism, through the guide mechanism as a stub end on which is located a mechanical cutting-thickness advance mechanism.