Selector valves

Claim 2

A selector valve including a casing having a first inlet connection, a second inlet connection, a service-line connection and an exhaust connection, a displaceable valve element housed in the casing and adapted for movement from a neutral position to at least one operative position, means provided both in the casing and in said element which when the element is in its neutral position define a first unloader passage connecting the inlet connection and the exhaust connection and which also define a subsidiary unloader passage connecting said second inlet connection to exhaust, and feed passage means, within the casing, which is communicable with a portion of said first unloader passage and with said first inlet connection, said element when moved away from said neutral position closing said first unloader passage and said subsidiary unloader passage and opening said feed passage means to said service-line connection.

Claim 3

A selector valve including a casing having a first inlet connection, a second inlet connection, a service-line connection and an exhaust connection, a displaceable valve element housed in the casing and adapted for movement from a neutral position to at least one operative position, means provided both in the casing and in said element which when the element is in its neutral position define a first unloader passage connecting the inlet connection and the exhaust connection and which also define a subsidiary unloader passage connecting said second inlet connection to exhaust, and feed passage means, within the casing, which is communicable with a portion of said first unloader passage and with said first inlet connection, said element when moved away from said neutral position closing said first unloader passage and said subsidiary unloader passage and opening said feed passage means to said service-line connection.

Claim 4

A selector valve including a casing having a first inlet connection, a second inlet connection, a service-line connection and an exhaust connection, a displaceable valve element housed in the casing and adapted for movement from a neutral position to at least one operative position, means provided both in the casing and in said element which when the element is in its neutral position define a first unloader passage connecting the inlet connection and the exhaust connection and which also define a subsidiary unloader passage connecting said second inlet connection to exhaust, and feed passage means, within the casing, which is communicable with a portion of said first unloader passage and with said first inlet connection, said element when moved away from said neutral position closing said first unloader passage and said subsidiary unloader passage and opening said feed passage means to said service-line connection.

Claim 5

A selector valve including a casing having a first inlet connection, a second inlet connection, a service-line connection and an exhaust connection, a displaceable valve element housed in the casing and adapted for movement from a neutral position to at least one operative position, first duct means formed partly in said casing and partly by said displaceable valve element which, when that element is in its neutral position forms a first unloader passage which at one end portion is open to said first inlet connection and which extends across the valve from said first inlet connection to said exhaust connection, further duct means formed partly in said casing and partly be said displaceable valve element which when that element is in its neutral position forms a subsidiary unloader passage which at one end portion is open to said second inlet connection and which extends from said second inlet connection at least part-way across said valve and is open at its other end portion to exhaust, adjustment of said displaceable valve element away from said neutral position towards said operative position moving the parts of said first unloader passage and of said subsidiary unloader passage formed by said displaceable valve element out of registry with the parts thereof in said casing thereby substantially simultaneously to close both said first unloader passage and said subsidiary unloader passage, and feed passage means, within the casing, which is communicable with a portion of said first duct means and with said first inlet connection, and which is associable with said displaceable valve element whereby when that element is in an operative position said feed passage means is placed in communication with said service-line connection.

Claim 6

A selector valve including a casing having a first inlet connection, a second inlet connection, a service-line connection and an exhaust connection, a displaceable valve element housed in the casing and adapted for movement from a neutral position to at least one operative position, first duct means formed partly in said casing and partly by said displaceable valve element which, when that element is in its neutral position forms a first unloader passage which at one end portion is open to said first inlet connection and which extends across the valve from said first inlet connection to said exhaust connection, further duct means formed partly in said casing and partly be said displaceable valve element which when that element is in its neutral position forms a subsidiary unloader passage which at one end portion is open to said second inlet connection and which extends from said second inlet connection at least part-way across said valve and is open at its other end portion to exhaust, adjustment of said displaceable valve element away from said neutral position towards said operative position moving the parts of said first unloader passage and of said subsidiary unloader passage formed by said displaceable valve element out of registry with the parts thereof in said casing thereby substantially simultaneously to close both said first unloader passage and said subsidiary unloader passage, and feed passage means, within the casing, which is communicable with a portion of said first duct means and with said first inlet connection, and which is associable with said displaceable valve element whereby when that element is in an operative position said feed passage means is placed in communication with said service-line connection.

Claim 7

A selector valve as claimed in claim 2, wherein said displaceable valve element is of spool type housed in a respective bore formed in said casing.

Claim 8

A selector valve including a casing having a first inlet connection, a second inlet connection, a service-line connection and an exhaust connection, a displaceable valve element housed in the casing and adapted for movement from a neutral position to at least one operative position, first duct means formed partly in said casing and partly by said displaceable valve element which when that element is in its neutral position forms a first unloader passage which at one end portion is open to said first inlet connection and which extends across the valve from said first inlet connection to said exhaust connection, further duct means formed partly in said casing and partly be said displaceable valve element which when that element is in its neutral position forms a subsidiary unloader passage which at one end portion is open to said second inlet connection and which extends from said second inlet connection at least part-way across said valve and is open at its other end portion to exhaust, feed passage means formed within said casing which is communicable with a portion of said first duct means and with said first inlet connection, and further passage means formed partly by said displaceable valve element and partly in said casing, being so disposed that with said displaceable valve element in an operative position they place said feed passage means and said service-line connection in communication, adjustment of said displaceable valve element away from the neutral position moving the parts of said first unloader passage and of said subsidiary unloader passage formed by the displaceable valve element out of registry with the parts thereof in the casing, thereby substantially simultaneously to close both said first unloader passage and said subsidiary unloader passage, and the displaceable valve element substantially simultaneously placing said feed passage means in communication with said service-line connection by way of said further passage means.

Claim 9

A selector valve including a casing having a first inlet connection, a second inlet connection, a service-line connection and an exhaust connection, a displaceable valve element housed in the casing and adapted for movement from a neutral position to at least one operative position, first duct means formed partly in said casing and partly by said displaceable valve element which when that element is in its neutral position forms a first unloader passage which at one end portion is open to said first inlet connection and which extends across the valve from said first inlet connection to said exhaust connection, further duct means formed partly in said casing and partly be said displaceable valve element which when that element is in its neutral position forms a subsidiary unloader passage which at one end portion is open to said second inlet connection and which extends from said second inlet connection at least part-way across said valve and is open at its other end portion to exhaust, feed passage means formed within said casing which is communicable with a portion of said first duct means and with said first inlet connection, and further passage means formed partly by said displaceable valve element and partly in said casing, being so disposed that with said displaceable valve element in an operative position they place said feed passage means and said service-line connection in communication, adjustment of said displaceable valve element away from the neutral position moving the parts of said first unloader passage and of said subsidiary unloader passage formed by the displaceable valve element out of registry with the parts thereof in the casing, thereby substantially simultaneously to close both said first unloader passage and said subsidiary unloader passage, and the displaceable valve element substantially simultaneously placing said feed passage means in communication with said service-line connection by way of said further passage means.

Claim 10

A selector valve as claimed in claim 4, wherein said casing further includes a second exhaust connection, the subsidiary unloader passage being connectible to exhaust through said second exhaust connection.

Claim 11

A selector valve as claimed in claim 5 and including a plurality of said displaceable valve elements arranged in banked manner, wherein at least one of said service-line connections is provided for each element, said first inlet connection and said second inlet connection being common to the banked valve.

Claim 12

A selector valve as claimed in claim 6, wherein each displaceable valve element is housed in an individual casing plate, the casing plates being assembled in stacked relationship.

Claim 13

A selector valve as claimed in claim 7, wherein said first inlet connection and said first exhaust connection are provided in end casing plates forming end closure portions for the stacked casing plates of the bank, all the casing plates together forming said casing.

Claim 14

A selector valve as claimed in claim 7, wherein the second inlet connection and the second exhaust connection are respectively formed one in one of said casing plates which houses a displaceable valve element, and the other in another of said casing plates which houses a displaceable valve eleMent.

Claim 15

A selector valve as claimed in claim 4, wherein the subsidiary unloader passage includes drillings provided in the casing and a drilling formed in and arranged transversely of said element, said drillings being in alignment when said displaceable valve element is in its neutral position.

Claim 16

A selector valve as claimed in claim 4, wherein a check valve is provided in said feed passage means, said check valve being openable only in a direction away from said inlet connection.