Control valves for hydraulic fluids

Claim 2

In a fluid flow solenoid-operated control valve comprising a housing, a first seating in said housing surrounding a port through which fluid can flow, a valve member for engagement with said first seating, a push-rod assembly for urging said valve member into engagement with said first seating, a pre-loaded spring acting on said push-rod assembly to urge said valve member into engagement with said first seating, a solenoid, an armature for moving said push-rod assembly away from said first seating upon energisation of said solenoid, and a lost-motion connection between said armature and said push rod assembly, the invention wherein said lost-motion connection comprises a first fixed abutment provided on said housing, a second abutment provided on the armature for direct mechanical engagement with said first abutment, the armature being free to remain with the two abutments in engagement with the solenoid is de-energised, and stop means for limiting movement of said push rod in a direction to urge said valve member into engagement with said first seating, the arrangement of the connection being such as to permit lost motion movement of said armature relative to said push-rod assembly in each direction of movement of said armature, the extent of said lost motion after said push rod assembly has engaged with said stop means being limited by engagement of said first and second abutments, whereby upon energisation of said solenoid said armature attains an initial momentum in taking up said lost before picking up the push-rod assembly, said push-rod assembly carrying a radial plate forming an abutment for one end of said pre-loaded spring of which the other end is in engagement with said first abutment at the end of said housing adjacent to said solenoid, whereby said preloaded spring acts in a direction to urge said valve member into engagement with said first valve seating.

Claim 3

In a fluid flow solenoid-operated control valve comprising a housing, a first seating in said housing surrounding a port through which fluid can flow,a valve member for engagement with said first seating, a push-rod assembly for urging said valve member into engagement with said first seating, a pre-loaded spring acting on said push-rod assembly to urge said valve member into engagement with said first seating, a solenoid, an armature for moving said push-rod assembly away from said first seating upon energisation of said solenoid, and a lost-motion Connection between said armature and said push-rod assembly, the invention wherein said lost-motion connection comprises a first fixed abutment provided on said housing, a second abutment provided on the armature for direct mechanical engagement with said first abutment, the armature being free to remain with the two abutments in engagement when the solenoid is de-energised, an enlarged head carried by said push-rod assembly at an end remote from said first seating, said head being received in a recess formed in said armature, screw means for adjusting the effective length of said push-rod assembly, and stop means for limiting movement of said push rod in a direction to urge said valve member into engagement with said first seating, the arrangement of the connection being such as to permit lost-motion movement of said armature relative to said push-rod assembly in each direction of movement of said armature, the extent of said lost motion after said push-rod assembly has engaged with said stop means being limited by engagement of said first and second abutments and the extent of said lost motion in the other direction being adjustable by said screw means and being limited by engagement of said armature and said head, whereby upon energisation of said solenoid said armature attains an initial momentum in taking up said lost motion before picking up the push-rod assembly.

Claim 4

In a fluid flow solenoid-operated control valve comprising a housing, a first seating in said housing surrounding a port through which fluid can flow,a valve member for engagement with said first seating, a push-rod assembly for urging said valve member into engagement with said first seating, a pre-loaded spring acting on said push-rod assembly to urge said valve member into engagement with said first seating, a solenoid, an armature for moving said push-rod assembly away from said first seating upon energisation of said solenoid, and a lost-motion Connection between said armature and said push-rod assembly, the invention wherein said lost-motion connection comprises a first fixed abutment provided on said housing, a second abutment provided on the armature for direct mechanical engagement with said first abutment, the armature being free to remain with the two abutments in engagement when the solenoid is de-energised, an enlarged head carried by said push-rod assembly at an end remote from said first seating, said head being received in a recess formed in said armature, screw means for adjusting the effective length of said push-rod assembly, and stop means for limiting movement of said push rod in a direction to urge said valve member into engagement with said first seating, the arrangement of the connection being such as to permit lost-motion movement of said armature relative to said push-rod assembly in each direction of movement of said armature, the extent of said lost motion after said push-rod assembly has engaged with said stop means being limited by engagement of said first and second abutments and the extent of said lost motion in the other direction being adjustable by said screw means and being limited by engagement of said armature and said head, whereby upon energisation of said solenoid said armature attains an initial momentum in taking up said lost motion before picking up the push-rod assembly.

Claim 5

The invention as claimed in claim 2 wherein said housing is provided with an outlet connection which incorporates a restriction to regulate flow of hydraulic fluid therethrough.

Claim 6

The invention as claimed in claim 3, wherein said restriction comprises an orifice in a plate removably mounted in a passage in said housing in connection with and of a diameter greater than, a port defining said outlet connection, and said plate is clamped between an inner end of a union screwed into said passage and a shoulder at a step in diameter between said passage and said port.

Claim 7

The invention as claimed in claim 4, wherein at least the edge of said plate which defines the end of said orifice facing said port is of a sharp substantially 90* outline.