Mine roof supports
A mine roof support has hydraulic props mounted between a floor sill and a roof bar which can be raised and lowered by extension and retraction of the props. A goaf shield is pivotably connected to the rear of the roof bar and is linked via levers to the floor sill. A hydraulic piston and cylinder unit is connected between the roof bar and the goaf shield. Apparatus serves to prevent damage to the support components, and especially to the unit which could be extended beyond its full stroke when the props are retracted to bring the goaf shield and the roof bar more or less into alignment. The protective apparatus is composed of a compact valve device operated by a member, such as a cam, to block the props from hydraulic pressure when the goaf shield and the roof bar assume a pre-determined angular disposition. Both the valve device and its operating member are disposed in a protected position within chambers formed inside the roof bar and the goaf shield adjacent the pivot connection therebetween.
- Assignee:
- Gewerkschaft Eisenhutte Westfalia (Germany, Federal Republic of)
- Patent Number(s):
- US 4422807
- OSTI ID:
- 6930723
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
012000* -- Coal
Lignite
& Peat-- Mining
42 ENGINEERING
420206 -- Engineering-- Mining & Drilling Equipment & Facilities-- (1980-1989)
CONTROL EQUIPMENT
DESIGN
EQUIPMENT
EQUIPMENT PROTECTION DEVICES
FLOW REGULATORS
HYDRAULIC EQUIPMENT
MECHANICAL STRUCTURES
MINE ROADWAYS
MINING
OPERATION
POWERED SUPPORTS
ROOFS
SHIELDS
STATIC LOADS
STRATA CONTROL
STRUCTURAL BEAMS
SUPPORTS
TUNNELS
UNDERGROUND FACILITIES
UNDERGROUND MINING
VALVES