Electromagnetic relay

An electromagnetic relay with an angular armature and a U-shaped yoke disposed on the coil form flange. The yoke comprises two legs extending in the direction of the coil axis, and a crosspiece having a foil-spring portion which rests on the angular edge of the tilting armature. The crosspiece carrying the foil-spring portion is clamped into position between the two legs. The crosspiece is made from a resilient material and is provided at its ends with flap members which engage into corresponding slots formed at the ends of the legs.

BACKGROUND OF THE INVENTION 
The present invention relates to an electromagnetic relay. 
Published German patent application DE-OS No. 30 08783 discloses a relay in 
which the coil form together with the U-yoke carrying the foil-spring 
portion consists of one single molded plastic part. This type of relay has 
proved well suitable in practice. However, to obtain high accuracies 
during manufacture of the relay, it is necessary to adhere exactly to the 
molding conditions of the coilform, especially to the temperature, and the 
mixing ratios in the case of plastic materials mixed with reinforcing 
fiber materials. 
It is the object of the present invention to permit an economical and 
qualitatively high-grade manufacture of the foil-spring portion while 
maintaining the same good or even better functioning thereof, in spite of 
low precision requirements in manufacturing the coilform. 
SUMMARY OF THE INVENTION 
According to the principal aspect of the invention, in a relay of the type 
described above the crosspiece with the foil-spring portion is an 
inexpensive punched part made of a suitable resilient material, such as 
spring bronze. By elastically deflecting the legs of the U-yoke of the 
relay and/or the crosspiece, the crosspiece can easily be engaged into 
slots formed in the legs. In this way, it is possible to replace the 
cross-piece with the foil-spring portion by a different one whose spring 
action acts in a different intensity and/or in a different angle upon the 
tilting armature of the relay. Thus, the coilform can also be used with 
differently designed tilting armatures, hence e.g., for different types of 
relays.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
FIG. 1 shows a relay coilform 1 injection-molded from an elastic plastic 
material. Molded to one flange 2 of the coilform are two legs 4, 5 
extending in the direction of the coil axis 3. Each leg 4 and 5 is 
provided at its end 6 with at least one slot 7. The slots are engaged by 
flap members 8 formed on the ends of a crosspiece 9 of an elastic 
resilient material. The engagement is effected by elastically deflecting 
the legs 4, 5 and/or the crosspiece 9. Both the slots 7 and the flap 
members 8 are so designed that there is obtained a fixing of the 
crosspiece 9 without any backlash. In this way, the legs 4, 5 together 
with the crosspiece 9 form a U-shaped yoke. 
The crosspiece 9 has an integral foil-spring portion 10 which resiliently 
presses against the angular edge of an angular tilting armature 12 of the 
magnetic circuit consisting of the core 13 and the magnetic yoke 14. A 
magnetic coil 15 is wound around the core of the coilform. The crosspiece 
9 with the integral foil-spring portion 10 may be formed of a resilient 
metal, such as spring bronze, by a stamping operation or the like. 
For increasing the strength of the coilform 1, especially when subjected to 
higher temperatures, the plastic material may be reinforced with fiber, 
such as glass fibers.