Apparatus for holding and releasing with rod-shaped release elements made of a shape memory alloy

1. An apparatus for holding and releasing a pin in a controlled manner, the apparatus comprising

a base,

a pin holding element supported at the base,

a plurality of rod-shaped release elements made of a shape memory alloy and supported at the base,

a holding force application device supported at the base and configured for applying an elastic holding force, and

a force transfer element,

wherein the force transfer element is subjected to the elastic holding force applied by the holding force application device, and wherein the force transfer element, against the elastic holding force, is supported at the base via a parallel arrangement of the pin holding element and the rod-shaped release elements,

wherein each of the rod-shaped release elements is arranged with radial play in a blind hole of a plurality of blind holes in the base, the plurality of blind holes being arranged around the pin holding element, and

wherein the pin holding element is deactivatable by heating up the rod-shaped release elements beyond a transition temperature of their shape memory alloy and by a resulting recovery of the rod-shaped release elements to straight memory shapes.

2. The apparatus of claim 1 , wherein the shape memory alloy has a one way memory effect.

3. The apparatus of claim 1 , wherein the transition temperature of the shape memory alloy is at least 70° C.

4. The apparatus of claim 1 , wherein a force transfer piece movably guided in the respective blind hole of the plurality of blind holes is arranged between the force transfer element and each of the rod-shaped release elements.

5. The apparatus of claim 1 , wherein the blind holes are parallel to a central pin seat in the pin holding element.

6. The apparatus of claim 1 , wherein the radial play is between 5% and 15% of a diameter of the rod-shaped release elements in total.

7. The apparatus of claim 1 , wherein the rod-shaped release elements have a square or circular cross section, wherein a length of the rod-shaped release elements is between 4-times and 40-times a diameter of the rod-shaped release elements.

8. The apparatus of claim 1 , wherein the pin holding element is a collet chuck with a central pin seat, wherein the collet chuck has an outer cone via which the collet chuck is supported at an inner cone of the base.

9. The apparatus of claim 8 , wherein equal cone angles of the outer cone and the inner cone are in a range from 10° to 20°.

10. The apparatus of claim 1 , wherein the holding force application device comprises a screw element having a screw thread engaging a counter-thread of the base.

11. The apparatus of claim 10 , wherein a thread axis of the counter-thread is parallel to a central pin seat of the pin holding element.

12. The apparatus of claim 10 , wherein the screw element is a screw cap screwed on the counter-thread of the base.

13. The apparatus of claim 12 , wherein, wherein the screw cap has a central pin opening.

14. The apparatus of claim 1 , wherein the holding force application device comprises a spring.

15. The apparatus of claim 14 , wherein the spring comprises at least one clover-leaf-shaped cup spring.

16. The apparatus of claim 1 and further including a heating device for heating the release elements.

17. The apparatus of claim 16 , wherein the heating device is configured to directly heat each of the release elements by directing an electrical current through the release elements.

18. The apparatus of claim 17 , wherein the heating device has at least one of an AC/DC converter, a DC/DC converter and a storage capacitor.

19. The apparatus of claim 17 , wherein electrical insulations are provided at outer circumferences of the rod-shaped release elements or at inner circumferences of the blind holes or both at outer circumferences of the rod-shaped release elements and inner circumference of the blind holes.