Abstract: The very fast circuit breaker assisted by semiconductor electronics. A piston 21 slides in an insulating housing 20 and along a center shaft 22. The piston 21 has of an exciting winding 25 and a magnetic yoke 26, which by cooperating with an armature 28, join the piston 21 to the center shaft 22, a shoulder of which renders possible the holding of a repulsion disk 34. The repulsion disk carries the moving contacts 35 and 36, which cooperate with the stationary contacts 37 and 38, when the piston is in its high position under the effect of a locking spring 24. Upon the injection of a current into the repulsion coil 45, the repulsion disk 34 is violently repulsed in the downward direction, while jumping the electromagnetic lock established between the magnetic yoke 26 and the armature 28. An admission of compressed air through an orifice 27 permits the descent of the piston 21.

Abstract: The apparatus has a striking mass which strikes a ball and a support for the ball to be struck. The ball is held to the support by a frame or by a suction apparatus. The ball may be given a curved trajectory by either rotating the ball support and ball or by rotating the striking mass at the time of impact.

Abstract: Device for propelling an inflated ball by elastic impact, includes an electromagnet 1, a plunger core 3 drawn by the coil, an oscillating lever 7, and a mechanical linkage 5, which connects the plunger core 3 to oscillating lever 7.The oscillating lever 7 is connected to a striking lever 13 which pivots around an axle 14 fixed to the free end of oscillating lever 7. Striking lever 13 is made up of two arms of unequal length. At the end of the excursion of oscillating lever 7, the shorter arm 15 of striking lever 13 strikes against stop 32 which stops arm 15 and contributes to the acceleration of the longer arm 16 of striking lever 13; the striking mass 17 attached at the end of striking lever 13 thus strikes the inflated ball 22 at maximum speed.