Electromagnetic relay

Details Electromagnetic relay Electromagnetic relay

1991-06-06

1992-10-13

Donovan, Lincoln

Electricity: magnetically operated switches, magnets, and electr

Electromagnetically actuated switches

Multiple contact type

335 86, 335 78, H01H 6702

Patent

active

051554593

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

The invention relates to an electromagnetic relay comprising a base plate and contact and connection parts fastened on the latter, as well as a magnet yoke which carries a coil core for receiving a relay winding and a hinged armature which is swivelably supported at the front side of the coil core and is provided with at least one switching contact which cooperates with a stationary working contact of a contact carrier fastened on the base plate.
In such a relay, which is known from DE-PS 36 40 997, the switching contact of the relay is adjusted by means of a squeezing process at a central leg of the contact carrier, the relay contact being fastened at the free end of the latter. The squeezing is effected in a stretch zone of the leg which is arranged between connecting webs at adjacent legs, which connecting webs project out symmetrically at both sides, and a yoke of the contact carrier which connects the three legs.
However, the use of such relays for switching on electromagnetic consumers such as electric motors, magnetic valves and the like is only possible to a limited extent because of the occurring high switch-on currents, since the silver-nickel alloy of the relay contacts causes a relatively low transition resistance, but leads to rapid wear of the contacts at high current loads. Therefore, with larger consumers or consumers with high switch-on current intensities it is known in motor vehicles to use relays with a main contact and preliminary contact according to DE-OS 30 08 089, wherein the preliminary contact is produced from a material which is resistant to burning, e.g. tungsten, for absorbing the high switch-on current; however, this material has a considerably higher transition resistance than the material of the main contact. In such relays, the advance or lead of the preliminary contact, as well as the burning reserve and contact pressure of the preliminary and main contacts, must be adjusted independently of one another. Until now, adjustment screws were normally arranged at the relay for this purpose. These adjustment screws necessitate costly production, assembly and adjustment and, moreover, must be secured after the adjusting process by means of glue or a weld joint. It is further known to adjust the main and preliminary contacts of such relays independently of one another at a contact carrier by means of a pressing or notching adjustment, as is known from DE-OS 30 12 354 (R. 6210). However, a disadvantage consists in that the contacts can be placed in a slanted or lopsided position by means of the notching or pressing process as a result of irregular material joints, which can lead to increased burning of the contacts.


SUMMARY OF THE INVENTION



Advantages of the Invention

The present solution endeavors to adjust the main and preliminary contacts of power relays in the simplest, most exact and reliable manner possible independently of one another and in the most economical manner possible.
In keeping with these objects the relay according to the invention is characterized in that, in addition to the work contact serving as main contact, a preliminary contact cooperating with a second switching contact of the hinged armature is arranged at the angled end of another middle leg which is connected with an adjacent leg of the contact carrier in each instance via additional connecting webs, which project symmetrically at both sides, and the middle leg likewise comprises a stretch zone between the yoke and the connecting web.
The relay, according to the invention has the advantage that the lead of the preliminary contact relative to the main contact, i.e. the contact sequence, as well as the contact pressure and consequently the so-called burning reserve, can be adjusted very accurately, quickly and reliably independently of one another without the adjusted values changing subsequently, e.g. as a result of elastic deformations during a bending adjustment of the contact carrier. Another advantage consists in that the contact carrier can be produced without gr

REFERENCES:
patent: 3068335 (1962-12-01), Gregg
patent: 4972166 (1990-11-01), Mitsch et al.

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