Automatic initial-cutting device for microtomes, particularly ultramicrotomes

摘要

A device automatically applies an object (7) to a cutting edge (11) of a knife 10), and automatically makes an initial cut in the object (7), in microtomes, especially ultramicrotomes. Force sensors (27,28), length sensors (29) or other sensors, an elecrotronic control unit (25) and an encoder (22) coupled to a drive device register forces (k,-k) connected with the separation of sections by the knife edge (11) or variations in the system triggered by these forces. Subsequently, via the electronic control unit (25), a transition from a rapid speed or rate of feed to a lower cutting speed or a lesser rate of feed for making an initial cut is automatically performed. A visual and/or acoustic signal informs the user of this change. Signals (S.sub.1, S.sub.2) from the sensors (27-29) serve for automatic adjustment of the position of two switch-over points (U.sub. 1, U.sub.2) from the rapid return speed (V.sub. R) to the slower cutting movement (V.sub.S) or from this slower cutting movement to the more rapid return movement (V.sub.R). In a further development, by electronic comparison of the force/time patterns or length/time patterns, the end of the initial cutting process is established and used for a fresh automatic variation in cutting speed (V. sub.S) and rate of feed.