Rod, in particular for a drill stem (string)

摘要

A rod (1), in particular for a small drill stem which can be put together from several rods (1a, 1b) of identical construction, is proposed, with which a small drill stem can be automatically set and extracted. To this end, the rod (1) is of hollow design and is provided with an axially displaceable plunger (2) in its interior, for which at least two further positions (P2, P3) can be assumed from a basic position (P1). Both the interlocking between the front rod (1a) and the drill chuck (20) and that between the front rod (1a) and the further adjoining rod (1b) is controlled by a push rod (21) performing strokes (H1, H2) in the drill chuck (20). <IMAGE>