Coupling arrangement for a telescopic device

1. A telescopic device comprising a first tubular element and an extension member displaceably arranged in an axial direction within the first tubular element, wherein a coupling member is provided relatively displaceable to the extension member, between at least,

a first axial position wherein the extension member is displaceable within the first tubular element, and

a second axial position wherein the coupling member engages between the extension member and the first tubular element limiting displacement in at least one longitudinal direction,

where the coupling member engages the interior of the first tubular element; and

wherein an outer surface of the coupling member is provided with treads.

2. A telescopic device according to claim 1 , wherein the coupling member engages an inner surface of the first tubular element.

3. A telescopic device according to claim 1 , wherein the coupling member is a coupling ring having an inner surface facing the extension member and an outer surface facing the first tubular element.

4. A telescopic device according to claim 3 , wherein the coupling ring is expandable from a first radial extent in the first axial position to a second radial extent in the second axial position and wherein the radial extent of the coupling ring is larger in the second radial extent than in the first radial extent

5. A telescopic device according to claim 3 , wherein the coupling ring is deformable.

6. A telescopic device according to claim 3 , wherein the coupling ring is formed of a high friction material.

7. A telescopic device according to claim 3 , wherein the inner surface of the coupling ring includes polytetrafluoroethylene.

8. A telescopic device according to claim 1 , wherein an outer surface of the coupling member is provided with at least one rib.

9. A telescopic device according to claim 1 , wherein an outer surface of the coupling member is provided with a high friction surface.

10. A telescopic device according to claim 3 , wherein the coupling ring is formed as an open ring, having a c-shape when seen in cross section.

11. A telescopic device according to claim 10 , wherein the coupling member is arranged around a conical surface of the extension member that tapers along the axial direction.

12. A telescopic device according to claim 11 , wherein the conical surface is provided as a separate bushing element attached to a distal end of the extension member.

13. A telescopic device according to claim 12 , wherein the bushing element is formed with a through-going opening along the axial direction.

14. A telescopic device according to claim 11 , wherein the conical shaped surface area is provided with a low friction surface.

15. A telescopic device according to claim 1 , wherein a frictional force F 1 , between an inner surface of the tubular element and an outer surface of the coupling member is larger than a frictional force F 2 , between an inner surface of the coupling member and the extension member.

16. A telescopic device according to claim 15 , wherein the extension member is a second tubular element.

17. A telescopic device according to claim 16 , wherein the telescopic device is a telescopic intermittent urinary catheter.

18. A telescopic device according to claim 17 , wherein the first tubular element is a distal section and the second tubular element is a proximal section of the telescopic intermittent urinary catheter.

19. A telescopic device according to claim 18 , wherein the inner surface of the first tubular element is provided with at least one protruding rim.

20. A telescopic device according to claim 19 , wherein the inner surface of the first tubular element is provided with at least one groove.