Patent ID: 6056480
Filing Date: 2000-05-02
Classification: E21D

Abstract:
A support for underground mining and tunnel construction, comprisingan outer tube (2) and an inner tube (3) which are pushable into each other in a telescoping manner;a piston (4) acted upon by a hydraulic pressure medium located in the outer tube and, upon admission of pressure, acts on the inner tube for extending the inner tube;said outer tube and said inner tube are fixable on each other at any length of extension by means of a mechanical locking device;said mechanical locking device (9) is positioned in a force-transmitting manner between the piston (4) and an inner end of the inner tube (3) and comprises an annular spreading-wedge type drive mechanism having two annular wedge elements (10, 11; 12, 13) axially pushable into each other over a limited distance of displacement;one of said wedge elements being supported on the piston (4) and another wedge element being supported on a bottom end (24) of the inner tube (3); one of the annular wedge elements (10, 11; 12, 13) rests against an inner circumference (28) of the outer tube (2) and is radially spread at an end of an axial path of displacement of the two annular wedge elements (10, 11; 12, 13) relative to each other by wedge action of the annular spreading-wedge type drive mechanism in a manner such that abutting wall areas of the outer tube (2) are radially deformed outwardly.