Patent · US Expired

Hydraulic mine prop

US4404893A · kind A · utility

3Cited by

5References

1Claims

0Family size

Assignee

Vereinigte Osterreichische Eisen- und Stahlwerke - Alpine Montan Aktiengesellschaft · AT

Inventors

Siegfried Sigott · Ferlach, AT
Heinrich Suessenbeck · Zeltweg, AT
Alfred Zitz · Zeltweg, AT
Gottfried Siebenhofer · Wien, AT

Key dates

Filing date	Mar 17, 1978
Grant date	Sep 20, 1983
Priority date	—
Expiry date	Mar 17, 1998

Classification

Technology area (CPC E)Fixed Constructions
CPC primaryE21D15/44
WIPO fieldCivil engineering
WIPO sectorOther fields

Abstract

A hydraulic mine prop includes an inner piston-like prop guided within an outer cylinder-like prop, and a roof fall valve. The interior space of said inner prop communicates freely with the working chamber of the prop, and the roof fall valve is arranged outwardly on the prop and rigidly secured thereon, the valve being connected to the working chamber by an orifice provided in the prop and leading to the working chamber. The cross-sectional area of the roof fall valve in its open position.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.