Hydraulic control systems and devices therefor

Claim 2

In a hydraulic control system including a source of pressure medium, a combination of valve devices and pressure medium conduits connected to consumer appliances and a manually operable control device for selectively actuating the valve devices to feed pressure medium to and from the applances to perform various operations, the improvement therein comprising at least some of the valve devices each having two servo-pistons and associated working chambers, the servo-pistons being adapted to operate the valve devices when pressure medium is conveyed to the associated working chambers, means operably connecting one of the working chambers to said control device and means operably connecting the other of the working chambers to part of the system for automatically effecting a sequence of operations on the appliances.

Claim 3

A system according to claim 1, wherein a plurality of said valve devices are formed into a common constructional unit with the control device.

Claim 4

A system according to claim 1, wherein the two servo-pistons of said valve device are disposed co-axially of one another.

Claim 5

A system according to claim 1, wherein each valve device having said two servo-pistons has two shut-off valves each with a closure element engageable on a seating with the closure elements being in engagement with a common plunger, the servo-pistons being adapted to act upon one of the closure elements to open one valve and shut the other valve.

Claim 6

A system according to claim 3, wherein the valve device has a housing and the two servo-pistons are displaceably mounted in a guide bush received in the housing, there being further provided two shut-off valves each with a closure element engageable on a seating with the closure elements being in engagement with a common plunger, the servo-pistons being adapted to act upon one of the closure elements to open one valve and shut the other valve, and wherein the closure elements are each mounted in a sleeve accomodated in the housing and the plunger extends through the seatings of the valves.

Claim 7

A system according to claim 1, wherein the control device has a setting position which initiates the automatic control sequence.

Claim 8

In combination with a mine roof support installation having a plurality of roof support assemblies, each having hydraulically operated props, and at least one shifting ram for moving the assemblies in relation to one another, a hydraulic control system comprising: a source of pressure medium, valve devices and pressure medium conduits connected to the props and the ram, and a manually operable control device for selectively actuating the valve device to actuate selected valve devices to cause pressure medium to be fed to and from the props and the ram to perform various operating steps, wherein at least some of the valve devices each have two servo-pistons and associated working chambers, the servo-pistons being adapted to operate the valve device when pressure medium is conveyed to the associated working chambers, means operably connecting one of the working chambers to the control device and means operably connecting the other of the working chambers to part of the system for automatically effecting a seQuence of operations on the props and the ram.

Claim 9

In combination with a mine roof support installation having a plurality of roof support assemblies, each having hydraulically operated props, and at least one shifting ram for moving the assemblies in relation to one another, a hydraulic control system comprising: a source of pressure medium, valve devices and pressure medium conduits connected to the props and the ram, and a manually operable control device for selectively actuating the valve device to actuate selected valve devices to cause pressure medium to be fed to and from the props and the ram to perform various operating steps, wherein at least some of the valve devices each have two servo-pistons and associated working chambers, the servo-pistons being adapted to operate the valve device when pressure medium is conveyed to the associated working chambers, means operably connecting one of the working chambers to the control device and means operably connecting the other of the working chambers to part of the system for automatically effecting a seQuence of operations on the props and the ram.

Claim 10

In a hydraulic control system including a source of pressure medium, a combination of valve devices and pressure medium conduits connected to consumer appliances and a manually operable control device for selectively actuating the valve devices to feed pressure medium to and from the appliances to perform various operations, the improvement therein comprising: the control device having a rotatable member and a fixed plate provided with a plurality of bores, and a further bore in the plate, the rotatable member having at least one bore therein which can be bought into sealed register with each of the plurality of bores in the plate as the member is rotated, the rotatable member also having a further bore which communicates with the further bore in the plate, there being further provided a shut-off valve operably disposed to open and close communication between the further bore in the member and the at least one bore in the member, at least some of the plurality of bores in the plate being in communication through suitable hydraulic lines with associated servo-control working chambers so that the manual operation of the control device causes an associated valve member to be actuated, each valve member further including a second servo-control working chamber, and means being provided to operably connect the second working chamber to part of the system for automatically effecting a sequence of operations on the appliances.

Claim 11

In a hydraulic control system including a source of pressure medium, a combination of valve devices and pressure medium conduits connected to consumer appliances and a manually operable control device for selectively actuating the valve devices to feed pressure medium to and from the appliances to perform various operations, the improvement therein comprising: the control device having a rotatable member and a fixed plate provided with a plurality of bores, and a further bore in the plate, the rotatable member having at least one bore therein which can be bought into sealed register with each of the plurality of bores in the plate as the member is rotated, the rotatable member also having a further bore which communicates with the further bore in the plate, there being further provided a shut-off valve operably disposed to open and close communication between the further bore in the member and the at least one bore in the member, at least some of the plurality of bores in the plate being in communication through suitable hydraulic lines with associated servo-control working chambers so that the manual operation of the control device causes an associated valve member to be actuated, each valve member further including a second servo-control working chamber, and means being provided to operably connect the second working chamber to part of the system for automatically effecting a sequence of operations on the appliances.

Claim 12

A system according to claim 8, wherein the control device has a lever for effecting rotation of the member and for effecting actuation of said valve.

Claim 13

A system according to claim 9, wherein the rotatable member is partly received in a housing attached to said plate and the rotatable member has an extension part which extends through an aperture in the housing and carries said lever.

Claim 14

A system according to claim 8, wherein the shut-off valve is in the form of a closure element biased by a spring against a seating, accomodated in an axial bore of the rotatable member which constitutes said further bore, said at least one bore is provided in a disc part of the member and there is provided a displaceable plunger for moving the closure element off the seating.

Claim 15

A system according to claim 8, wherein the plurality of bores in the plate lie on a common pitch circle with its centre at the rotational axis of the rotatable member, the further bore in the plate is aligned with the rotational axis of the member, and the plate has another bore disposed between said pitch circle and the further bore end communicating with an annular gap disposed between the rotatable member and an inner planar face of the plate.

Claim 16

A system according to claim 12, wherein said at least one bore in the rotatable member contains a sealed sleeve adapted to be urged into sealing relationship with said planar face of the plate by means of the pressure of the pressure medium conveyed therethrough.

Claim 17

A system according to claim 8, wherein there is provided detent means for causing the rotatable member to be indexed into various angular positions as the member rotates so that each of the plurality of bores in the plate is successively brought into communication with said at least one bore in the rotatable member.

Claim 18

A system according to claim 8, wherein the rotatable member is received in a housing attached to the plate, there being provided roller bearings located between the housing and the member.

Claim 19

In combination with a mine roof support installation having a plurality of roof support assemblies, each with hydraulically operated props, and at least one shifting ram for moving the assemblies in relation to one another, a hydraulic control system comprising: a source of pressure medium, valve devices, at least some of the valve devices each having two servo-pistons and associated working chambers, the pistons being adapted to operate the valve devices when pressure medium is conveyed to eiTher working chamber, and pressure medium conduits connected to the props and the ram, a manually operable control device being settable to various operating positions to actuate selected valve devices to cause pressure medium to be fed to and from the props and the ram to effect various operating cycles including extension and retraction of certain of the props and shifting of certain of the assemblies, means operably connecting one of the working chambers of each valve device with the control device and means operably connecting the other of the working chambers of each valve device to part of the system for automatically effecting a sequence of operations, wherein the control device includes a setting which when adopted causes the retraction of the props of one assembly and the shifting of the assembly effected by the automatic ram to be initiated simultaneously.

Claim 20

In combination with a mine roof support installation having a plurality of roof support assemblies, each with hydraulically operated props, and at least one shifting ram for moving the assemblies in relation to one another, a hydraulic control system comprising: a source of pressure medium, valve devices, at least some of the valve devices each having two servo-pistons and associated working chambers, the pistons being adapted to operate the valve devices when pressure medium is conveyed to eiTher working chamber, and pressure medium conduits connected to the props and the ram, a manually operable control device being settable to various operating positions to actuate selected valve devices to cause pressure medium to be fed to and from the props and the ram to effect various operating cycles including extension and retraction of certain of the props and shifting of certain of the assemblies, means operably connecting one of the working chambers of each valve device with the control device and means operably connecting the other of the working chambers of each valve device to part of the system for automatically effecting a sequence of operations, wherein the control device includes a setting which when adopted causes the retraction of the props of one assembly and the shifting of the assembly effected by the automatic ram to be initiated simultaneously.

Claim 21

An installation according to claim 16, wherein the control device comprises: a rotatable member and a fixed plate provided with a plurality of bores, and a further bore in the plate, the rotatable member having at least one bore therein which can be brought into sealed register with each of the plurality of bores in the plate as the member is rotated, the rotatable member also having a further bore which communicates with the further bore in the plate, there being further provided a shut-off valve operably disposed to open and close communication between the further bore in the member and the at least one bore in the member, at least some of the plurality of bores in the plate being in communication through suitable hydraulic lines with associated servo-control working chambers so that the manual operation of the control device causes an associated valve member to be actuated, each valve member further including a second servo-control working chamber, and means being provided to operably connect the second working chamber to part of the system for automatically effecting a sequence of operations on the appliances.

Claim 22

An installation according to claim 16, wherein the control device has settings whereat some of the props of one of the support assemblies are extended and retracted independently of the remaining props of the assembly.

Claim 23

An installation according to claim 16, wherein the control device has a setting whereat a sequence of operations composed of the retraction of the props of one of the assemblies, the shifting of said one assembly and the subsequent extension of the props is effected automatically.