초록 ▼

A hydraulic pilot valve has a joystick which is normally maintained in a neutral position by coil springs acting on plungers which engage corresponding first cam surfaces of a cam fixed to the joystick. The plungers are each connected to respective valve members which are stroked to open the pilot v

A hydraulic pilot valve has a joystick which is normally maintained in a neutral position by coil springs acting on plungers which engage corresponding first cam surfaces of a cam fixed to the joystick. The plungers are each connected to respective valve members which are stroked to open the pilot valve when the plungers are depressed. When the joystick is pivoted to depress one of the plungers so as to stroke one of the valve members, that valve member is held stroked by an magnetic detent. The joystick may then be released and the valve member will remain in its stroked position. When the joystick is moved back towards a neutral position, a second cam surface on the joystick engages an outer end portion of the depressed plunger and applies an axial force to the plunger. This disengages an armature component of the magnetic detent from an electromagnetic component. A spring then pushes the plunger to its neutral position where the plunger holds the valve member operated thereby closed. In accordance with one embodiment, one joystick operates two or more valve members and, in accordance with another embodiment, the pilot valves are stacked.

대표청구항 ▼

In a joystick operated hydraulic valve having a casing with at least first and second work ports; at least first and second valve members disposed to open and close the respective first and second work ports, and at least first and second operating plungers each having outer ends and being biased to

In a joystick operated hydraulic valve having a casing with at least first and second work ports; at least first and second valve members disposed to open and close the respective first and second work ports, and at least first and second operating plungers each having outer ends and being biased to a neutral position within the casing, the first and second operating plungers being engageable with the first and second valve members; at least one joystick pivotally mounted on the casing and operably engaging end surfaces of the outer ends of the operating plungers to allow pivotal movement of the joystick in one direction to cause one of the operating plungers to move inwardly toward from a neutral position a depressed position to stroke the respective valve, while the other operating plunger remains in the neutral position; the improvement comprising: at least first and second detents within the casing for latching against axial movement the first and second plungers, respectively; each of the detents having first components which are stationary with respect to the first and second plungers and second components which are fixed to the first and second plungers, the second components being disposed between the outer ends of the plungers and the first components and acting to hold the respective operating plunger depressed and the valve members stroked; first cam surfaces on the joystick for engaging the end surfaces of the outer ends of the first and second plungers, the first cam surfaces depressing the first plunger to stroke the first valve member upon pivoting the joystick in a first direction and depressing the second plunger to stroke the second valve member upon pivoting the joystick in a second direction; and second cam surfaces on the joystick for engaging the outer ends of the plungers when the plungers are depressed to pull the plungers and disengage the first and second components of the detents from one another so as to unstroke the valves.