A feed system, rack bar and drive sprocket for moving an underground winning machine having a travel drive with drive sprocket having symmetrically profiled teeth, and rack bars with a plurality of rack teeth being arranged between a supporting strip and a guide strip of the rack bar. The tooth flanks of the teeth are inclined in the direction of movement and diverge towards the tooth tip for the interaction with tooth surfaces of teeth of drive sprocket. In order to improve the interaction between the teeth and produce less wear, the two tooth flanks of each rack tooth are concavely arched and form a trough between guide strip and supporting strip transversely to the direction of movement, with the trough rising towards the tooth tip, and the two tooth surfaces of each drive sprocket tooth is convexly arched and forms a crown transversely to the direction of movement.