Patent EA-001010-B1 (EA)
Title: Removable cover of an endoscope shaft
Inventor: AXON ANTHONY THOMAS ROGER
IPC: A61B1/00
Filed: 1997-05-23
Abstract: 1. A removable cover for an endoscope shaft, characterised in that the cover comprises an elongate sleeve (4) of thin elastic material arranged for application over an endoscope shaft (2) for surface contact between the sleeve and shaft to hold the sleeve against movement longitudinally of the shaft during displacement of the shaft through a body passage into which the shaft is inserted in use, the outer surface of the sleeve providing a low frictional resistance during at least forward displacement of the endoscope shaft through the body passage and a greater frictional resistance during rearward displacement of the endoscope shaft. 2. A cover according to claim 1, wherein the outer surface of the sleeve has protrusions (5, 6) inclined rearwardly at a shallow angle. 3. A cover according to claim 2, wherein the protrusions have the fonn of fish scales or bristles. 4. A cover according to claim 1, wherein the sleeve has portions (8) of wedge-shaped profile in longitudinal section. 5. A cover according to any of claims 1 to 4, wherein the sleeve (4) is made from elastic material, such as polyurethane, polychloroprene or natural rubber. 6. A cover according to any one of claims 1 to 5, wherein the external surface of the sleeve is treated to modify the surface friction thereof. 7. A cover according to claim 6, wherein the external surface has a low friction coating. 8. A cover according to claim 6, wherein the external surface has a lubricant applied thereto. 9. A cover according to any of claims 1 to 8, wherein the sleeve (4) has a line of weakness extending therealong to facilitate lengthwise tearing of the sleeve for removal of the sleeve from the endoscope. 10. A cover according to any one of the preceding claims wherein the sleeve is accommodated in an annular housing (10) having a central aperture through which the endoscope shaft (2) is movable during application of the sleeve to the shaft. 11. An endoscope comprising an elongate flexible shaft (2) having a proximal end connected to viewing means (1) and a free distal end (3), characterised in that the shaft (2) has along at least part of its length an exterior surface providing less frictional resistance to forward movement than to reverse movement. 12. An endoscope as claimed in claim 11, wherein the exterior surface is defined by a removable sleeve which covers at least part of the length of the elongated shaft from the distal end thereof. 13. An endoscope as claimed in claim 11 or 12, wherein the exterior surface comprises protrusions inclined at a shallow angle. 14. An endoscope as claimed in claim 13, wherein the protrusions comprise fish scales (5). 15. An endoscope as claimed in claim 13, wherein the protrusions (8) are wedge-shaped. 16. An endoscope as claimed in claim 13, wherein the protrusions comprise bristles (6). 17. An endoscope as claimed in any of claims 11 to 16, wherein the exterior surface can be modified to facilitate removal of the shaft from the body passage. 18. An endoscope as claimed in claim 18, wherein the exterior surface is defined by an inflatable sleeve. 19. An endoscope as claimed in any of claims 11 to 18, wherein the surface is defined by a sleeve which can be remotely separated from the elongated shaft thereby, in use, to allow separate withdrawal of the sleeve and flexible shaft from the body passage. 20. A cover for an endoscope shaft (2), comprising an elongate sleeve (4) characterised in that the sleeve (4) outer surface is adapted so that, when fitted to an endoscope shaft, it can provide greater frictional resistance to rearward displacement of the endoscope shaft than the frictional resistance to forward movement of the shaft.