Hermann Hemscheidt Maschinenfabrik Gmbh & Co.

Hermann Hemscheidt Maschinenfabrik Gmbh

Hermann Hemschedit Maschinenfabrik Gmbh & Co.

Maschinenfabrik Gmbh & Co.

Hermann Hemscheidt Maschinenfabrick Gmbh & Co.

Karl Krieger

Werner Reinelt

Josef Welzel

Gunther Kuschke

Willi Kuster

Gunter Kuschke

Guy Guens

Horst Schurmann

Jochem Hartleb

A pressure-control valve is connected to a working cylinder of an hydraulic, walking, mine roof support on one side of the piston in the cylinder. In its function as a pressure-limiting valve, it regulates the pressure in the working cylinder in dependence upon a predetermined pressure in a control conduit which is connected to the pressure chamber of a prop of the mine roof support. Through it a spring-loaded control piston of the pressure-control valve is hydraulically loaded so as to act on a spring-loaded valve closure member in the pressure-control valve. The control piston holds the valve-closure member in the closure position if the pressure in the control conduit exceeds the predetermined pressure. If the pressure in the control conduit drops off, the valve-closure member then regulates the pressure in the working cylinder to a comparatively low value.

Pressure-control valve

The control valve for the re-setting of the props at a predetermined minimum setting pressure is connected at respective junctions to a high pressure conduit, to the pressure chambers of the props, to the prop-setting conduit and to the return-flow conduit leading to the annular chambers of the props. The spring-loaded closure body is guided displaceably in the valve housing by journals on each of the two sides of the valve cone. The ends of the journals are formed as actuation faces. The valve cone seals off the high pressure junction and the junctions leading to the pressure chambers of the prop and opens only when a predetermined minimum setting pressure at the junction is exceeded. For closure, the control valve is loaded through the junction on the actuation area of the journal with the pressure fluid conducted to the annular chambers of the props.

Prop control valve

Valves regulating the supply of hydraulic fluid to hydraulic cylinders of an hydraulic walking mine-roof support are controlled by apparatus comprising an axially-movable switching shaft provided with cams which is rotatable into successive switching stations where it is immobilized by spring-loaded stop pins to that the cams bear on tappets to actuate the respective valves, there being a switching spring acting on the shaft to return the shaft to its initial position of rest after it has been axially displaced and rotated out of that position of rest.

Hydraulic valve control apparatus

A pressure-limiting valve comprises a cylindrical actuator piston guided displaceably in a bore and held under the pressure of a spring in the closure position of the valve. Longitudinally-directed throughflow passages are formed in the actuator piston on the pressure-loaded end and are arranged concentrically with respect to the central axis and open into an annular groove extending around and in the circumferential surface of the actuator piston. This groove is sealed off by a gasket mounted in the bore wall. When the set pressure predetermined by the closure spring is exceeded, the actuator piston travels with the gasket over the annular groove so that the pressure medium can flow away through the outlet opening.

Pressure-limiting valve

An hydraulically-controlled non-return valve for the hydraulic cylinders of a walking mine-roof support is provided with a cylindrical valve-closing member which is spring-loaded in the closing direction and is guided in a valve case in a valve housing, the valve-closing member being sealed off therein by means of a seal. A space on one face of the valve-closing member is connected to a circulating duct by way of a stepped bore in the valve case, which bore contains a spring-loaded throttle member having through-flow bores of which one has a throttle-like reduced cross-section. During setting of the hydraulic cylinder pressurized fluid flows past the opened valve-closing member through inclined bores and, by way of the circulating duct, to the stroke space of the hydraulic cylinder. During retraction of the hydraulic cylinder, a control piston in the non-return valve is loaded at the same time as an annular space in the hydraulic cylinder. The control piston thus lifts the valve-closing member from a valve seat so that the pressurized fluid flows back in the reverse direction. The said space bounding the valve-closing member is connected to the throttle member in such a manner that the valve-closing member is not caused to oscillate by the pressurized fluid flowing back during retraction of the hydraulic cylinder.

Hydraulically-controlled non-return valve

An arrangement for controlling an electro-hydraulic valve having an armature of the magnet which performs a greater displacement stroke than the closure body of the valve and, following on the switching movement of the valve, initially tensions a spring buffer arranged between the armature and a push-rod switch. The armature rests directly in contact against a housing of the valve in the switched position, thus generating a remanence force, and, after completion of switching, the voltage applied to the coil of the magnet is reduced by electronic means to an extent such that the closure body of the valve is held in the switched position by the combined magnetic force induced by the reduced residual voltage and the remanence force. The initially-tensioned spring buffer, on switching off the residual voltage, generates an air-gap which eliminates the remanence force between the housing and the armature so that the closure body of the valve is then returned to the starting position by the valve force.

Arrangement for controlling an electro-hydraulic valve

A pressure-limiting valve for hydraulic fluids comprises a stepped switching piston which is loaded by a closing spring to oppose high fluid pressure obtaining in an inflow duct of the valve. Radial transverse bores branch from an axially-extending bore in the switching piston. When the setting pressure established by the closing spring is exceeded, the transverse bores in the piston move past an O-ring seal as the piston compresses the spring, and pressure fluid thus flows from the axially-extending bore into a discharge duct of the valve. The stepped switching piston is guided in a pressure chamber by a portion of its cross-section which is greater than that in the zone of the O-ring seal. Adjacent the inflow duct, the axially-extending bore in the piston has a reduced flow cross-section. Further radial bores lead from the axially-extending bore in the piston in the region of the stepped portion of the latter.

Pressure-limiting hydraulic valve

A 3-port, 2-position, directional control valve has two cylindrical closure elements for the alternate connection of a control line to a return flow line and a high pressure line. The switching force exerted on a thrust member is transmitted via pressure pins, and a manifold member with a centrally-positioned axial bore connected to the control line is arranged between the closure elements. Sealing elements on the closure elements seal the exit openings of the bore in the manifold member alternately. One of the pressure pins extends through the manifold member eccentrically while extending parallel to the axial bore and is always under pressure, like the high-pressure-side closure element, so that the closure element on the low pressure side is always held open in the zero position of the valve while the closure element on the high pressure side is acted on by the pressure medium in the direction of closure. The switching force required to open the valve is small because the pressurized cross-sections of the axial bore and the pressure pin are constructed to be small.

3-Port, 2-position directional control valve

A control device for the sequential control of an advancing mine-roof support comprising pressure-controlled directional control valves alternately connectable to a high pressure line and to a return line in order to convert a pressure pulse into a switching step at the main control unit of the advancing mine-roof support and for transmitting an answering pressure pulse signalling the completion of the workstage for continuing the sequence.

Mine-roof support control means

A control line connects an annular space in an auxiliary hydraulic cylinder of an hydraulically-movable mine-roof support (the auxiliary cylinder being provided to advance a forward, auxiliary, roof-support canopy in the direction of the working face of a mine) to the displacement space of an hydraulic measuring cylinder which is longitudinally displaceable in a direction parallel to the hydraulic advancing cylinder in order to advance the auxiliary roof-support canopy, which is pivoted to the main roof-support canopy, in synchronism with the advancing cylinder mounted in the base of the mine-roof support and attached to an abutment on the working face side of the support. A control valve is connected to the control line and responds to the control line pressure in such a way that, when the pressure falls, it supplies pressurized fluid into the pressure space of the auxiliary cylinder to extend the piston rod thereof, and shuts off again when the pressure increases. An axial bore in the piston rod of the advancing cylinder preferably serves as the measuring cylinder.

Mine-roof support control mechanism

A control device serves to control the fluid flow to and from double-acting rams, especially the rams of mining machinery, the control device having various internal ducts which are defined between two plates connected together. One of the two plates (a duct plate) has a main face formed with channels, some of which radiate outwardly from a ring of bores, and two of which are `T`-shaped and extend generally tangential to the ring of bores. The other plate (a connecting plate) closes the channels to define ducts and has bores communicating with the various ducts. Control valve units are detachably connected to the connecting plate, the control valve units being arranged to be actuated to effect desired connections between the various ducts by way of the bores in the connecting plate.

Double-plate control device

A control unit for controlling the supply of fluid to a hydraulic jack, the control device including a main valve having a valve member normally held closed by pressure in a pressure chamber, the pressure chamber being fed with fluid through a bore in a valve member of the main valve. In one embodiment, a valve spindle slides in the bore to stop it being blocked. In another embodiment, designed to control a double-acting jack, the main valve is associated with a second similar main valve the pressure chamber of which is fed from the first main valve instead of through a bore in its valve member.

Hydraulic jack control device

A control device for controlling hydraulically actuated equipment, the device comprising a fluid distributing block and a plurality of control valve units detachably mounted side-by-side on the block, the block being formed with an inlet opening, an outlet opening, a plurality of control line openings, a plurality of delivery openings, a plurality of return openings, a plurality of valve unit communicating openings, and internal passage means, the said internal passage means connecting the inlet opening with each of the delivery openings, connecting the outlet opening with each of the return openings, and connecting the control line opening with respective corresponding ones of the valve unit communicating openings.

Control device

A multiple valve control device for use with a hydraulic walking mine-roof support frame, comprising a valve housing containing control valves which are disposed concentrically to a central axis around a central filter into which an axially-extending control-medium feed duct enters and from which radial bores extend in a star pattern towards the control valves, the said control valves, which are provided with valve pistons, being actuated via operating members from the valve-housing endface which is provided with a cover.

Multiple valve control device

An hydraulic controller comprising: a casing; first and second inlets and a plurality of outlets associated with the casing; a flow-directing member rotatable in the casing; first and second passages extending through the flow-directing member, the flow-directing member being rotatable in the casing to each of a plurality of selected positions for directing liquid from the said inlets to selected ones of the outlets by way of said passages, each said first and second passage having an inlet end connected to a respective one of the first and second casing inlets, and having an outlet end connected to a selected one of the said several casing outlets according to the selected position of the said flow-directing member; first and second valves mounted in the flow-directing member and movable to open and close said first and second passages respectively; and locking means which operate in at least one of the said selected positions of the flow-directing member to prevent movement of the said first valve to a position for opening said first passage.

Growing community of inventors

Wuppertal, Germany

Karl Krieger