Expansion screw for regulating teeth

1. An expansion screw for regulating teeth, having two expansion-screw bodies and a spindle, and spacing between the bodies, the spacing between which can be changed by means of the spindle, and at least one guide pin which is aligned parallel to the spindle and engages guide openings of the two expansion-screw bodies, the spindle having a first threaded portion and a second threaded portion, each of which is connected to an expansion-screw body, and an actuating portion, with at least one point for application of a tool for rotating the spindle, and the expansion screw having a locking mechanism which interacts with the actuating portion in order to secure the spindle against unintended rotation, wherein

the locking mechanism has at least one locking element with a locking member which is disposed laterally alongside the actuating portion and subjects the actuating portion to a spring force that is axially aligned with respect to the longitudinal axis of the spindle when the spindle is rotated, and

the locking member has at least one latching element which is adapted to be latched, in at least one angular position of the spindle, to a corresponding latching element disposed on an axial end face of the actuating portion.

2. The expansion screw according to claim 1 , wherein at least one end face of the actuating portion has disposed on it a plurality of latching elements which are spaced apart from one another at uniform angular spacings.

3. The expansion screw according to claim 1 , wherein the at least one latching element of the locking member is configured as a latching protrusion, and wherein at least one latching element of the actuating portion is configured as a latching indentation which is disposed on an end face of the actuating portion and into which the latching protrusion penetrates.

4. The expansion screw according to claim 1 , wherein the at least one latching element of the locking member forms a positive lock with the at least one latching element of the actuating element.

5. The expansion screw according to claim 1 , wherein the locking element is produced from a flat material.

6. The expansion screw according to claim 1 , wherein the locking element comprises sheet metal.

7. The expansion screw according to claim 1 , wherein the spindle has an annular groove laterally alongside the actuating portion, into which groove the locking element penetrates.

8. The expansion screw according to claim 1 , wherein the locking element has a U-shaped or C-shaped bracket which encompasses the spindle.

9. The expansion screw according to claim 1 , wherein the locking element has at least one retaining arm which projects outward from the locking member and is retained on the guide pin.

10. The expansion screw according to claim 9 , wherein the at least one retaining arm has an opening through which the guide pin engages.

11. The expansion screw according to claim 9 , wherein the at least one retaining arm is fixed in an axially immovable manner on a guide pin.

12. The expansion screw according to claim 1 , wherein the expansion screw has two guide pins, between which the spindle is disposed, and wherein the locking member forms a central portion of the locking element, and this central portion is disposed on the spindle and subjects the actuating portion to an axial spring force when the spindle is rotated, and wherein the locking element has first and second retaining arms which are directed away from one another, adjoin the central portion and are each retained in captive fashion on a guide pin.

13. The expansion screw according to claim 12 , wherein the two retaining arms are each of L-shaped configuration and have a first, axially oriented portion and a second, radially oriented portion.

14. The expansion screw according to claim 1 , wherein the locking mechanism has two locking elements, the locking members of which are each disposed laterally at an end face of the actuating portion and subject the actuating portion to an axial spring force in each case when the spindle is rotated.

15. The expansion screw according to claim 14 , wherein the two locking elements encompass the actuating portion between them.

16. The expansion screw according to claim 15 , wherein the locking elements each have a central through-passage opening through which the spindle engages, and wherein the locking elements are each secured on at least one guide pin.