Apparatus for controlling the feed of the tool electrode of an electro-erosion machine

The apparatus for controlling the feed of the tool electrode contains a transducer (1) for the electric resistance which is applied on the input side to the erosion section (2) connected to the pulse generator (3) of the electro-erosion machine. The output of the transducer (1) is connected to the input (5) of a comparison element (4), to the other input (7) of which a normal signal source (6) is applied, while its output is connected to an actuating member (8) for the feed control. The apparatus also has a timing pulse generator (9) which is attached to the generator (3) and the transducer (1) for periodically interrupting the pulse generation by the transducer (3) and for simultaneously switching the transducer (1) to the measurement of the electric resistance of the erosion section (2). The invention can be used in electro-erosion copy-broaching machines and cutting-out machines.