Patent GB-1046941-A (GB)
Title: Control means for hydraulically operated advancing roof supports
Inventor: HANCOCK KENNETH GEORGE
IPC: E21D23/00
Filed: 1963-03-26
Abstract: 1,046,941. Advancing mine roof supports. ELECTRO-HYDRAULICS Ltd. March 13, 1964 [March 26, 1963], No. 11991/63. Heading F1P. In a roof support comprising a plurality of hydraulically operated props 1-4 and an advancing ram 5, the roof support is controlled by independently operable control valves 11, 20, 12, the first valve 11 being operable to control the operation of the advancing ram 5, the second valve 20 being operable to select raising or lowering of the props 1-4, and the third valve 12 being operable to control the supply of hydraulic pressure fluid from a conduit 6 through the second valve 20 to the prop lock valves 26-29. As shown, the first valve 11 connects both sides of the ram 5 to a conduit 13 communicating with a tank, and the props 14 are supporting the roof by fluid retained therein by the lock valves 26-29, the unlocking connections 41, 42, 45, 46 thereof being connected through the second valve 20 to the tank. To advance the props 1, 2 the second valve 20 is moved and the third valve 12 is opened to allow pressure fluid to unlock the valves 26, 27 which thereby allow the props to discharge through a conduit 33 and passages 31, 30, 14 to the tank. When the props are clear of the roof the third valve 12 is closed and the first valve 11 is moved to cause the ram 5 to extend and hence advance the lowered props 1, 2. After advance the valves 11, 20 are returned to their original positions, and the third valve 12 is opened until the props 1, 2 re-support the roof. The props 3, 4 are advanced in a similar manner to the props 1, 2 viz. valve 20 is moved to its other position, the third valve 12 is opened, then closed after collapse of the props, the first valve is moved to its other position to close ram 5 and thereby advance the props, whereafter the valves 11, 20 are returned to their original positions and the third valve 12 is opened. Yield valves 26A, 27A, 28A and 29A, are associated with respective props 1-4. The control valves 11, 12, 20 are formed as a single assembly 8 (Fig. 3, not shown). The first valve 11 comprises passages in a valve plate 55 and a co-operating valve rotor 57 having passages registerable with the passages in the valve plate 55. The rotor 57 is manually rotatable by a spindle 58 to three distinct positions determined by detents 62 selectively engageable by a spring loaded ball 63. The second valve 20 is of a similar construction and includes a valve plate 64, a rotor 65 and a spindle 66 keyed thereto and having detents 73 engageable by a spring loaded ball 73. The third valve 12 is coaxial with the second valve 20 and comprises a valve 77 which co-operates with a seat 75 and has a stem 78 movable to open the valve by a plunger 82 depressable by a lever 71. The valves 11, 20 are described in greater detail in Specification 1,027,633. The assembly 8 is connected to the conduits 6, 13 by a manifold 85 containing two non- return valves (Fig. 4, not shown) which automatically close when the manifold is disconnected. A restrictor 23 allows rapid pressure decay in the line 21 when the valve 12 is closed.