Abstract: An electromagnetic switch comprising primary current contacts having rounded contact surfaces inclined to the longitudinal axis of the electromagnetic switch, and a rotatable contact bridge having a spherical contact surface with a radius of curvature which is less than the radius of a rounded contact surface of a primary current contact.

Abstract: An electromagnetic switch for starting mechanisms of internal combustion engines whose switching pin (22), which carries the contact bridge (29) for the main current contacts (13 and 14), is provided with a guide sleeve (25) with which the switching pin (22) is supported and guided in a magneto armature (15) and in a magnetic core (2). The switching pin (22) is supported at springs (21 and 36) and, accordingly, at the magneto armature (15) and the magnet core (2) by means of the guide sleeve (25). An armature return spring (21) supported at the magneto armature (15) contacts the guide sleeve (25). A stronger pressure spring (36) supported at the magnet core (2) contacts the guide sleeve (25). The magneto armature (15) and the switching pin (22), together with the guide sleeve (25), can move relative to one another.

Abstract: A contact rod (19) carrying the contact bridge (25) for the starting current contacts of an engine starter circuit has, at its end inserted in the armature (15) of the solenoid a stop (21 and 23) against which the return spring (33) bears and which also serves to guide the switch rod within the armature. The return spring forces the component group, including the switch rod and the contact bridge, to move with the armature. This component group is readily assembled automatically in manufacture. After the excitation winding is deenergized, the armature, switch rod and contact bridge are moved back into the rest position by the full force of the return spring so that any sticking or welding of the contact bridge to the main current contacts is loosened, and damage therefrom prevented.

Abstract: The starting mechanism has a solenoid switch combination 11 for causing gear meshing engagement of a drive pinion 4 with a gear 31 of an internal combustion engine via an engagement lever 16 and a gear engagement mechanism 5-8. A pre-compressed spring 28 is disposed between the engagement lever 26 and the armature 18. The force of that spring aids the magnetic force of the solenoid switch 11 for pulling the armature 18 into the solenoid 11 against the force of a gear mesh spring 21 if the pinion 4 and the gear 31 are in the tooth-to-tooth position to engage the starter motor switch of the combination 11 and cause rotation of the motor, permitting engagement of the pinion 4 and gear 31.

Abstract: In order to effectively disconnect a contact bridge from fixed terminals, even though the contact bridge may be sticking to the contacts, or may be welded or hang, a plunger-type armature core is slidable within a central sleeve of a solenoid for a travel path which is in excess of the connecting path length of the contact bridge towards the fixed terminals. Upon disconnection, a spring returns the armature plunger and, with it, a switching rod which will pass through the overtravel path length before engaging the contact terminals, if the contact terminals should stick, thus exerting a blow against the connecting bridge and tearing it away from the contact terminals.