Patent ID: 8333099
Filing Date: 2012-12-18
Classification: B21D,F16B

Abstract:
1. A method for making a tube for a telescopic device, the method comprising the steps of: providing a semi-product of the tube with a desired value of length by cutting a section from long tubular raw material; pressing the wall of the semi-product of the tube for a first time to make cavities on an external side of the wall of the semi-product of the tube; and pressing the wall of the semi-product of the tube for a second time to deepen the cavities so that the tube is made with a desired depth, wherein each of the cavities is defined by an abutting facet, a guiding facet located substantially opposite to the abutting facet, a supporting face extending between the abutting facet and the guiding facet, and two lateral facets between which the abutting facet, the guiding facet and the supporting facet extend, wherein an angle between the abutting facet and the external side of the wall of the tube is larger than an angle between the guiding facet and the external side of the wall of the tube.