Microtome and method for positioning a microtome specimen head

A microtome (1), having a sectioning knife (4) and having a specimen head (5) movable relative to the sectioning knife (4) between a reference position (z1) and a lower position (z0);

• the microtome (1) comprising:
• an electric drive system (16) for motorized movement of the specimen head (5);
• a handwheel (8) coupled to the specimen head (5) via a mechanical drivetrain (15) comprising a crank mechanism, the handwheel (8) being manually operable for moving the specimen head (5);
• a sensor (21) for detecting the presence of the specimen head (5) at the reference position (z1), wherein the sensor (21) is configured to detect a dead center position of the crank mechanism to detect the presence of the specimen head (5) at the reference position (z1);
• an upper sensor (19) for detecting the presence of the specimen head (5) in an upper position below the reference position;
• a lower sensor (20) for detecting the presence of the specimen head (5) in a lower position (z0);
• and
• a control device (18) for controlling the electric drive system (16) and for processing signals of the sensor (21), the upper sensor (19), and the lower sensor (20),
• the control device (18) being configured to control the electric drive system (16) to:
• move the specimen head (5) downward initially at a first speed in reaction to detection of the presence of the specimen head (5) at the upper position by the upper sensor,
• move the specimen head (5) downward at a second speed that is slower than the first speed until detection of the presence of the specimen head at the lower position by the lower sensor,
• move the specimen head (5) at the first speed in reaction to detection of the presence of the specimen head (5) when the specimen head leaves the lower position (z0) by the lower sensor (20), and
• halt the specimen head (5) in reaction to detection of the presence of the specimen head (5) at the reference position (z1).