Heavy duty relay with resilient normally-open contact

1. A heavy duty relay for switching a current of 40 A to 1 kA, comprising:

a changeover spring resiliently deflectable by means of a switching force and having a contact point;

a normally-open contact against which the contact point of the changeover spring is electrically conductively pressed in a switching position, the switching position being resiliently deflected out of a resting position, the normally-open contact being arranged on a normally-open spring contact having a greater spring stiffness than the changeover spring;

wherein at least one of the changeover spring and the normally-open spring contact have a deflection region at least partially surrounded by a weakened zone, such that the spring stiffness is reduced in the deflection region relative to the region surrounding the weakened zone, the weakened zone being constructed as a pair of slots, each of the slots extending in a direction of a line of symmetry of the changeover spring or the normally-open spring contact.

2. The heavy duty relay according to claim 1 , wherein the spring stiffness of the normally-open spring contact is at most approximately 8 times the spring stiffness of the changeover spring.

3. The heavy duty relay according to claim 2 , wherein the spring stiffness of the normally-open spring contact is at most approximately 5.5 times the spring stiffness of the changeover spring.

4. The heavy duty relay according claim 1 , wherein the spring stiffness of the normally-open spring contact corresponds at least to the spring stiffness of the changeover spring.

5. The heavy duty relay according to claim 1 , wherein the material thickness of the normally-open spring contact is at most approximately 6 times the material thickness of the changeover spring.

6. The heavy duty relay according to claim 5 , wherein the material thickness of the normally-open spring contact is at least approximately 1.5 times the material thickness of the changeover spring.

7. The heavy duty relay according to claim 6 , wherein the material thickness of the normally-open spring contact is in about 0.25 mm.

8. The heavy duty relay according to claim 7 , wherein the material thickness of the changeover spring is in the region of 0.15 mm.

9. The heavy duty relay according to claim 1 , wherein at least one contact point of the changeover spring or the normally-open spring contact is provided with a contact bead, the surface of the substantially spherically arcuate contact bead protruding from the plane of the changeover spring or the normally-open spring contact.

10. The heavy duty relay according to claim 9 , wherein the contact bead is arranged asymmetrically displaced relative to the line of symmetry of the changeover spring or normally-open spring contact.

11. The heavy duty relay according to claim 1 , wherein the weakened zone is asymmetrically arranged relative to a line of symmetry of the changeover spring or normally-open spring contact.

12. The heavy duty relay according to claim 11 , wherein one slot is arranged on each side of the contact point between a force application point for the switching force and the contact point.

13. The heavy duty relay according to claim 11 , wherein the weakened zone substantially follows the contour of the contact point.

14. The heavy duty relay according to claim 11 , wherein the contact bead is arranged in the deflection region.

15. The heavy duty relay according to claim 11 , wherein the weakened zone is arrange on the changeover spring.

16. A heavy duty relay for switching a current of 40 A to 1 KA, comprising:

a changeover spring resiliently deflectable by means of a switching force and having a contact point;

a normally-open contact against which the contact point of the changeover spring is electrically conductively pressed in a switching position, the switching position being resiliently deflected out of a resting position, the normally-open contact being arranged on a normally-open spring contact having a greater spring stiffness than the changeover spring;

wherein at least one of the changeover spring and the normally-open spring contact have a deflection region at least partially surrounded by a weakened zone, such that the spring stiffness is reduced in the deflection region relative to the region surrounding the weakened zone, the weakened zone being constructed as a slot extending from a side of the changeover spring or the normally-open spring contact having a force application point for the switching force in a direction perpendicular to a line of symmetry of the changeover spring or the normally-open spring contact.

17. The heavy duty relay according to claim 16 , wherein the weakened zone is arranged between the contact point and a fastening point of the changeover spring or the normally-open spring contact.

18. The heavy duty relay according to claim 16 , wherein the weakened zone is asymmetrically arranged relative to the line of symmetry of the changeover spring or normally-open spring contact.

19. The heavy duty relay according to claim 16 , wherein the contact point includes a contact bead, the contact bead being asymmetrically displaced relative to the line of symmetry of the changeover spring or normally-open spring contact.

20. The heavy duty relay according to claim 18 , wherein the slot extends below the contact point.