Patent ID: 9371846
Filing Date: 2016-06-21
CPC Classification: F15B

Claim Text:
1. A telescopic hydraulic cylinder, comprising: an inner cylindrical tube; an outer cylindrical tube located concentrically around the inner cylindrical tube; and a guide ring for guiding the inner and outer cylindrical tubes while moving in longitudinal direction with respect to each other, wherein a first side of the guide ring has a cylindrical support surface with a center line and wherein a second opposing side of the guide ring has a guide surface, wherein the guide ring is mounted with its cylindrical support surface located in a cylindrical groove in either the outer surface of the inner cylinder or the inner surface of the outer cylindrical tube, and wherein the guide surface is configured to slide over the inner surface of the outer cylindrical tube or the outer surface of the inner cylindrical tube respectively; wherein a cross-section of the guide surface in a plane that includes the center line comprises a curved profile which has a radius of curvature larger than a radius of the guide surface of the guide ring in a plane perpendicular to the center line; and wherein all tangent lines to the curved profile form a tangent angle with the center line of between zero and five degrees.