Abstract: An electro-hydraulic control device (10, 60) for a hydraulic servo motor for controlling a volume flow is proposed, which is embodied as a 4/2 valve module. A blocking valve in accordance with seat valve technology between a motor connection (B) and a return flow (R) form a lowering element (11), while the associated unblocking member (44) is designed as a longitudinal slide (45), which controls the connection between an inflow connection (P) and a motor connection (A) and is actuated by a proportional magnet (16). After unblocking the blocking valve, its seat valve body (23) is mechanically taken along by the longitudinal slide (45), and the two volume flows are proportionally controlled via the lowering element (11) and the lifting element (12), so that a large switching capacity is achieved along with a construction with few leaks.

Abstract: A hydraulic circuit in a monoblock structure for lifting and lowering a load has at least two electromagnetically actuatable proportional distributing valve elements, a check valve, a pressure balance for load-independent lifting of the load as an input element, a housing accommodating at least some of the elements and having at least one pump connection, at least one consumer connection, and at least one return connection, the proportional distributing valve elements being disposed parallel to one another, electromagnetic drives seated side-by-side on a same side and at a same height, the pressure balance having a piston which is disposed coaxially next to a longitudinal slide of a first one of the proportional distributing valve elements in a bore that guides and supports both the valve elements, the longitudinal slide of the first proportional distributing valve elements being spring-loaded, and at least one component for adjusting a prestressing and bracing of a spring on the housing of a control penetrat

Abstract: An electrohydraulic control device (10) for a double-acting consumer (11) is proposed, in which a continuous volumetric flow control to and from the consumer (11) is possible with two proportional 4/2-way magnet valves (12, 13), each with one seat valve function (26), and by means of two blocking valves (29, 38) of the seat valve type; free floating is attainable as the fourth work position. The magnet valves (12, 13) are structurally identical and are each connected into the volumetric flow to the consumer and the volumetric flow leaving the consumer; each consumer connection (28, 36) is sealed off tightly by a seat valve function (26) of the magnet valves (12, 13) and a blocking valve (29, 38). The magnet valves (12, 13) have a main control member (57) and a pilot control member (58), which cooperate in the manner of a followup controller and make do without a separate control oil supply, so that high hydraulic capacities can be controlled continuously and with short response times.

Abstract: A control device for a volume stream of a hydraulic working medium has a blocking valve having a seat valve body cooperating with a stationary main valve seat, a pre-control valve member arranged in the seat valve member and cooperating with a valve seat provided with the seat valve member, an actuating device with which the pre-control valve member is in an operative communication, a spring providing a force with which the pre-control valve member cooperates with the valve seat and controls a pressure in a pressure chamber formed in the seat valve member and a valve housing.

Abstract: The control valve for keeping constant viscosity and temperature of a pressure medium in a hydraulic circuit includes a preliminary control valve which supports a temperature sensitive control element and adjustable throttling means including a throttling plunger controlled by the control element; a control slider arranged in the valve upstream of the preliminary control valve is provided with first throttling means for admitting pressure medium against the preliminary control valve to establish a bypass connection in addition to the main connection controlled by the slider; to avoid excessive temperature increase of the medium in the case of a damage of the control element, a temperature sensitive shearing pin is provided between the control element and the throttling plunger to cause an override of the plunger to a position in which an additional bypass connection is established which prevents throttling and thus temperature increase of the pressure medium.

Abstract: A pressure tank includes a hollow container which has an outlet for discharging fluid therefrom. The outlet is provided with a valve seat, for receiving a valve member which is slidably mounted in the container above the valve seat for respective movement between an open position, so that fluid in the container can flow therefrom through the outlet and a closed position so as to prevent discharging of fluid out of the container. A flexible partition is provided in the container, subdividing the interior thereof into a gas-containing compartment and into a liquid-containing compartment. The partition is displaceable on expansion of gas in the gas compartment, into an extended position immediately adjacent the outlet. An element is connected to the valve member, which element cooperates with the partition in the extended position of the same so as to prevent premature movement of the valve member into the closed position until the container is empty.

Abstract: A piston rod connected at one end to a piston slidably arranged in a cylinder projects with its other end through an opening in an end wall of the cylinder beyond the latter and a fork-shaped member is connected by a friction weld, that is without adding welding material or external heat, to the other end of the piston rod.

Abstract: A hydrostatic power steering system wherein the steering wheel can rotate a pilot pump which is connected with compartments at the opposite ends of a spool reciprocably received in a valve body having ports connected with a main pump, a reservoir, the chambers of a power cylinder whose piston is connected with the steering linkage, and with spaces defined by the valve body with two plungers disposed at the opposite ends of the spool. The spool is normally held in a neutral position by two centering springs which react against the respective plungers and bias two retainers into engagement with the spool. The plungers are connected to each other by a rod which is reciprocable in an axial bore of the spool.

Abstract: An electrohydraulic control device (10) for a double-acting consumer (11) is proposed, in which a continuous volumetric flow control to and from the consumer (11) is possible with two proportional 4/2-way magnet valves (12, 13), each with one seat valve function (26), and by means of two blocking valves (29, 38) of the seat valve type; free floating is attainable as the fourth work position. The magnet valves (12, 13) are structurally identical and are each connected into the volumetric flow to the consumer and the volumetric flow leaving the consumer; each consumer connection (28, 36) is sealed off tightly by a seat valve function (26) of the magnet valves (12, 13) and a blocking valve (29, 38). The magnet valves (12, 13) have a main control member (57) and a pilot control member (58), which cooperate in the manner of a followup controller and make do without a separate control oil supply, so that high hydraulic capacities can be controlled continuously and with short response times.