The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 10, 1981
Filed:
Jan. 23, 1980
Voest-Alpine Aktiengesellschaft, Vienna, AT;
Abstract
The mine roof supporting structure comprises hydraulic props (3) which are pressing a swivelling cap (8) against the mine roof. A link lever (5) is pivotally linked to the floor frame (1) and a shield (4) is pivotally linked to the link lever (5) and to the cap (8). The shield (4) is pulled in direction to the floor frame (1) by means of a hydraulic tension strut (14). The working chamber (24) of the tension strut (16), which working chamber includes the piston rod and is facing the pivotal point (12) of the tension strut (16) to the shield (4), can be brought in connection with the supply conduit (19) for feeding pressurized fluid to the props (3) via a spring loaded check valve (22, 23), noting that the opening pressure of the spring (22) is smaller than the final supporting pressure exerted by the props (3). The piston surface of the working chamber (24) is smaller than the piston surface (4) delimiting the working chamber of the props (3). A change-over valve (25) is provided for connecting in one position the supply conduit (19) and in the other position a separate conduit (28) for pressurized fluid with the hydraulic tensions strut (14), noting that in the other position the connection between the conduit for pressurized fluid and the working chamber (21) of the props is closed (FIG. 3).