the corresponding stop magnets 26 if then the holding force of the stop magnets 26 is overcome the movement of the heddle via the corresponding push and pull rod 30 is brought about predominantly by the spring force of the spiral tension and compression spring 8 the electric motor 32 cooperating in this movement without appreciably contributing to it when the other end position is reached that is to say for example the lever 28 comes into the active range of the lower stop magnet 26 the new end position is reached and the spiral tension and compression spring 8 remains deflected since in this position the force of the permanent magnet 26 is higher than the restoring force of the spiral tension and compression spring 8 and the electric motor 32 does not assist the latter in the exemplary embodiment shown here the spiral tension and compression spring 8 is operated in the linear range so that the spring force graph 100 can be represented by a straight line the spring force is assisted only insignificantly by the warp thread force 106 and therefore the warp thread force 106 plays no part here the stop magnet graph 102 clearly shows the short range of the magnetic forces which act only when the levers 28 are in the immediate vicinity of the stop magnets 26 and an end position is assumed the coil force graph 104 of the electric motor 32 has in the operating mode described here a constant force which may point in one direction or the other depending on polarity in the exemplary embodiment described here the electric.