Patent Number: 
Section: claims

1. A device for determining a position of a component that is moveable in a linear manner along an assigned axis, the device comprising:a reference element that extends in a direction of the assigned axis, the reference element being assigned to the component, the component operable to be brought into mechanical contact with the reference element; anda piezo transducer arranged on the reference element, the piezo transducer operable to generate and receive vibrations in the material used for the reference element,wherein the component is in mechanical contact with an edge of the reference element, on which the piezo transducer is arranged,wherein the mechanical contact between the component and the reference element is created with a sliding or rolling element, andwherein the sliding or rolling element is moveable in a groove of the reference element. 2. The device as claimed in claim 1, wherein the reference element comprises a panel that is attached to a supporting frame. 3. The device as claimed in claim 1, wherein there is a contact pressure of 5-10 N. between the sliding or rolling element and the reference element. 4. The device as claimed in claim 1, wherein the reference element and the sliding or rolling element are magnetized. 5. The device as claimed in claim 1, wherein the groove is conically shaped. 6. The device as claimed in claim 1, wherein side walls of the groove are coated with a non-magnetic material. 7. The device as claimed in claim 1, wherein side surfaces of the sliding or rolling element are coated with a non-magnetic material. 8. The device as claimed in claim 1, wherein the device is configured to determine a position of a leaf of a multi-leaf collimator operable to shape a beam in an X-ray device. 9. The device as claimed in claim 1, wherein the device is configured to determine a position of an examination couch of a medical device. 10. A method for determining a position of a component that is moveable in a linear manner along at least one assigned axis, the method comprising:generating a vibration signal in a reference element using a piezo transducer that is affixed to the reference element, the reference element extending in a direction of the at least one assigned axis; andreceiving a vibration signal that is reflected on a point of contact between the component and the reference element, a position of the point of contact on the reference element being determined from a time difference between generation and the reception. 11. The method as claimed in claim 10, wherein generating the vibration signal comprises generating the vibration signal on an edge of the reference element, the edge being in touching contact with the component. 12. The method as claimed in claim 11, further comprising generating the point of contact between the component and the reference element by attaching a sliding or rolling element of the component to the edge of the reference element. 13. The method as claimed in claim 12, wherein the sliding or rolling element is attached magnetically. 14. The method as claimed in claim 12, wherein the sliding or rolling element is attached with a force of 5-10 N. 15. The method as claimed in claim 10, further comprising generating the point of contact between the component and the reference element by attaching a sliding or rolling element of the component to an edge of the reference element. 16. The method as claimed in claim 15, wherein the sliding or rolling element is attached magnetically. 17. The method as claimed in claim 13, wherein the sliding or rolling element is attached with a force of 5-10 N. 18. A device for determining a position of a component that is moveable in a linear manner along an assigned axis, the device comprising:a reference element that extends in a direction of the assigned axis, the reference element being assigned to the component, the component operable to be brought into mechanical contact with the reference element; anda piezo transducer arranged on the reference element, the piezo transducer operable to generate and receive vibrations in the material used for the reference element,wherein the component is in mechanical contact with an edge of the reference element, on which the piezo transducer is arranged,wherein the mechanical contact between the component and the reference element is created with a sliding or rolling element, andwherein the reference element and the sliding or rolling element are magnetized.