Abstract: An electromagnetic pilot valve cartridge which is directly mountable on a pilot pressure activated directional valve and which has a valve barrel for interconnection with a socket portion of a directional valve housing. The valve barrel has laterally disposed fluid communication openings respectively coupled to a pressure fluid passage and a drain passage in the directional valve housing. A pilot flow opening is disposed at an end portion of the valve barrel and is separated from the laterally disposed fluid communication openings by a seal ring, and a flow restricting device is associated with the pilot flow opening. The flow restricting device includes an end cap mounted on the end portion of the valve barrel and a flow restricting opening and an annular shoulder for axially supporting the seal ring.

Abstract: A control means for a hydraulic motor connected to an external load comprises a directional valve (10) for selectively feeding hydraulic fluid to the motor from a pressure source and including load pressure sensing means (24, 25) connected to a load compensating valve (15) located upstream of the directional valve (10) for adjusting automatically the feed pressure in relation to the actual load pressure. The load compensating valve (15) includes a valve spindle (28) with opposite end surfaces (29, 30), one of which is exposed to the load pressure whereas the other is exposed to the feed pressure, and a selectively activatable feed pressure reducing means (38, 43; 50-57) for increasing the bias force acting on the load compensating valve spindle (28) in the closing direction of the latter in relation to the bias force acting in the closing direction of said valve spindle (28).

Abstract: A device for controlling a hydraulic motor (10) comprises a directional valve (15) connected to a pressure fluid pump (11; 50) via a feed passage (17) and a pilot valve (19) activated safety shut-off valve (18) incorporated in the pressure fluid feed passage (17) between the pump (11; 50) and the directional valve (15) and shiftable from a normally open position to a closed position to, thereby, block the fluid communication between the pump (11; 50) and the directional valve (15) in emergency situations. A shunt valve (16) for short circuiting at least a part of the pump flow to a tank or, alternatively a displacement adjusting means (51) of a variable displacement pump (50) are activated by a load sensing pressure derived from a load sensing port (15e) on the directional valve (15), which load sensing pressure is discharged to tank (12) via the shut-off valve (18) as the latter is shifted to its closed position.

Abstract: A controller for a hydraulic motor (11) comprises a directional valve (12) for communicating hydraulic pressure fluid from a pressure source (10) to the motor (11), a pilot pressure operated activating device (13, 14), pilot valves (17, 18) connected to the activating device (13, 14) and to the pressure source (10), and a manually operable activating lever (15) mechanically connected to the directional valve (12) via a coupling (24, 55, 56). A pressure fluid operated actuator (25, 47, 48) is associated with the coupling (24, 55, 56) to shift the coupling when pressurized from an engaged condition and a disengaged condition, and a mode shifting valve (19) is connected both to the actuator (25, 47, 48) and to the pilot valves (17, 18) and is arranged to pressurize simultaneously the pilot valves (17, 18) and the actuator (25, 47, 48) of the coupling (24, 55, 56) to avoid double activation of the directional valve (12).

Abstract: A method for controlling a hydraulic motor with a hydraulic valve comprising an inlet section which includes a pump and tank connection and a maneuvering section having a slide (B1) and a load signal system (L1, L2, L3). The hydraulic valve also includes two regulating constrictions (S3, S4) which can be connected to and from a motor (C), such as a hydraulic piston-cylinder device. The maneuvering slide (B1) also includes a load level detecting constriction (S2) and a load signal drain (S5), and the pump generates an idling pressure. When maneuvering the maneuver slide (B1), the load signal Ps of the load signal system is increased by a further constriction (S1) located between the pump connection and that side of the load detecting constriction (S2) that has the higher pressure during the maneuvering process.