An electrically controlled drive with a slow-cutting, fast-return cycle for rotary microtomes

A microtome drive, which gives a low cutting speed for the specimen and a fast return to the cutting position, was constructed. To this end, a low speed and a high speed shaft, from an electric motor with a reducing gear, are alternately coupled to the final drive shaft. This coupling is obtained by means of a magnetic clutch and a specially designed pawl clutch. Alternation of low and high speed of the drive shaft depends on the action of the magnetic clutch which is governed by a specimen position contact through a relay system. The specimen position contact is actuated by the microtome itself, which leads to its fully automatic operation. The combination of a magnetic and a pawl clutch in the drive results in a vibration free two-speed cycle of the microtome.