A hydraulic control assembly includes means for holding pressure in a cylinder to inhibit boom or arm drop of a machine in the event that a hose between the cylinder and a main control valve (MCV) ruptures. The pressure holding means of the hydraulic control assembly include a hydraulic valve and a parts-in-body check assembly both configured for insertion into a valve cavity defined by a valve body. The hydraulic valve comprises a proportional piloted valve that controls pressure.

A return manifold includes a housing having a first workport, a second workport, a third workport, and a fourth workport, and defining a first chamber and a second chamber. The return manifold includes a back-pressure disk arranged between the first workport and the first chamber, a bypass disk arranged between the first chamber and the second chamber, a back-pressure spring biased between the back-pressure disk and the bypass disk, and a bypass spring biased against the bypass disk. The back-pressure disk and the bypass disk are hydro-mechanically coupled so that movement of the bypass disk alters a force on the back-pressure disk and movement of the back-pressure disk alters a force on the bypass disk.

An in-port sequencing valve configured to be utilized with a clamping device of a workpiece clamping system having a fixture plate, a number of fixture datums, and a number of clamping devices. The in-port sequencing valve includes a housing, a pre-load adjuster, a valve spring, and a valve piston. The pre-load adjuster is configured to be set to a selected valve activation setting. The valve spring is compressed an amount corresponding to the valve activation setting. The valve piston is configured to be shifted from a closed position to an open position when a force due to hydraulic fluid pressure overcomes a threshold spring force of the valve spring corresponding to the valve activation setting. The in-port sequencing valve can be set to a selected valve activation setting so that the clamping devices clamp the workpiece in a selected order according to the valve activation setting.

A hydraulic drive system for a track device of crawler type has right and left hydraulic track motors. The hydraulic drive system is capable of correcting for skew occurring in the straight line traveling of the track device. A traveling test is conducted upon shipment from a factory. If skew is noted during the test, a plug disposed on the side of a valve opening-side pressure receiving portion of a pressure compensating valve for the track which is lower in speed is removed and, replaced with an adjusting mechanism-mounted plug having an adjusting pin. The pin is operated so as to strengthen a biasing force of a target compensating differential pressure adjusting spring. An opening in the pressure compensating valve is thereby corrected in an opening direction and a flow rate to one of the left and right track motors is thereby adjusted to be equal to the other motor.

A hydraulic control assembly includes means for holding pressure in a cylinder to inhibit boom or arm drop of a machine in the event that a hose between the cylinder and a main control valve (MCV) ruptures. The pressure holding means of the hydraulic control assembly include a hydraulic valve and a parts-in-body check assembly both configured for insertion into a valve cavity defined by a valve body. The hydraulic valve comprises a proportional piloted valve that controls pressure.

The present invention relates to a hydraulic apparatus, in particular to a hydraulic valve or to a hydraulic regulator, having a housing, at least one piston axially displaceably supported in a housing bore, and a respective at least one compression spring acting on the at least one piston, wherein at least one externally accessible regulating screw is adjustable within the housing bore to set the preload of the compression spring in the axial direction, wherein the adjustment distance of the at least one regulating screw is divided into at least two adjustment ranges and the torque to be applied for the adjustment of the regulating screw is larger in a second adjustment range than in a first adjustment range.

The invention relates to a pressure-limiting device designed to be installed in a system comprising a first line (11) and a second line (12) that can comprise pressurised oil, as well as comprising a discharge and/or booster line (10). The device also comprises a pressure selector (130, 150) in the form of a cage defining two seats (132, 134) and two pressure relief valves (160, 180). The limiting device is characterised in that it further comprises at least one means (170, 172; 190, 192) for regulating a pressure relief valve, disposed on the outside of an axial end of the pressure selector (150), in the form of a cage that allows the loading of the associated pressure relief valve to be regulated.

A flow limiter for a cut-off valve of a hydraulic pumping system and a hydraulic system using such a flow limiter. The flow limiter provides for limiting a flow through a cut-off valve. The flow limiter for a cut-off valve of a hydraulic pumping system includes a valve body with a hollow channel. The hollow channel has a fluid inlet and a fluid outlet, and the fluid inlet is in fluid communication with a discharge line of the cut-off valve in a mounted state of the flow limiter. A valve element is slidably arranged within the channel and can transition from a first position towards a second position, if a predefined fluid pressure threshold is exceeded at the fluid inlet. The valve element is arranged in the hollow channel so that in the second position a fluid flow from the fluid inlet to the fluid outlet is larger than in the first position.

A load-controlled hydraulic supply for an attachment attached to an agricultural tractor includes a hydraulic high-pressure source providing a volume flow in a supply line, a pressure-compensated control valve including an actuation device for adjusting the volume flow in the supply line, a return line leading to a hydraulic reservoir, and a load-indicating line. The volume flow is adjusted based on pressure feedback prevailing at the load-indicating line.

A load-controlled hydraulic supply for an attachment attached to an agricultural tractor includes a hydraulic high-pressure source providing a volume flow in a supply line, a return line leading to a hydraulic reservoir, and a load-indicating line connected to a device for pressure limiting. The volume flow is adjusted based on pressure feedback prevailing at the load-indicating line.