Work machine with spring loaded brake and prestressed spring device providing idle travel

A work machine, such as a truck, has a spring loaded brake 2, e.g. a parking brake, which is engaged by a spring 5a, 5b and released when connected via a hydraulic circuit to a pump 15. When a service brake input device, e.g. pedal 25, is pushed downwards it operates a pressure reducing valve 8a which reduces the pressure in line 7 thereby allowing the brake 2 to be engaged. A prestressed spring device 26 is connected between the pedal 25 and the valve 8a so as the pedal 25 is activated in a direction of a reduction in brake release pressure a short idle travel of the pedal 25 is achieved. This idle travel last up to a point when a braking torque of the spring loaded brake 2 is built up and a long actuation travel of the pedal 25 can be made available thereby reducing the pressure in the brake 2 in a controlled manner so that the brake 2 is used as a meterable service brake.

Hydrostatic drive system for mobile equipment, drives loading unit in accordance with braking pressure in travel drive

During braking or idling operation of the travel drive (4), the loading unit (20) is driven as a function of the braking pressure arising in the travel drive.

Hydrostatisches Antriebssystem

Die Erfindung betrifft ein hydrostatisches Antriebssystem (1) mit einer im Fördervolumen verstellbaren Pumpe (2), die zur Versorgung mindestens eines Verbrauchers (6) vorgesehen ist, wobei eine Fördervolumenstelleinrichtung (10) der Pumpe (2) mittels eines Vorgabesignals in Richtung einer Erhöhung des Fördervolumens beaufschlagt ist und in Abhängigkeit von einem den überschüssig geförderten Volumenstrom der Pumpe (2) erfassenden, hydraulischen Rückstellsignal in Richtung einer Verringerung des Fördervolumens beaufschlagt ist, wobei zur Erzeugung des Rückstellsignals eine Umlaufdruckwaage (20) vorgesehen ist, die in einem eine Förderleitung (5) der Pumpe (3) mit einem Behälter (4) verbindenden Strömungspfad angeordnet ist und in einer Rückstellsignalerzeugungsstellung (20b) das hydraulische Rückstellsignal erzeugt. Die Aufgabe, ein derartiges hydrostatisches Antriebssystem zur Verfügung zu stellen, das bei geringem Bauaufwand einen Abbau eines Leistungsvolumenstroms der Pumpe zu dem Behälter ...

Hydrostatic drive system for an excavator comprises a maximum pressure protection unit which is assigned to the pressure load recording line which acquires the pressure load of the consumer

Hydrostatic drive system comprises a maximum pressure protection unit (13) which is assigned to the pressure load recording line (5) which acquires the pressure load of the consumer (4). Preferred Features: The maximum pressure protection unit is formed as a pressure limiting valve. A pressure influencing unit (9) for delimiting the pressure load is provided for controlling the drive force and/or driving torque of the consumer.

Regulating valve device i.e. differential pressure regulator, for use as e.g. adjusting motor in hydrostatic load sensing drive system, has differential pressure presetting device presetting hydraulic control pressure or electrical force

The device (10) has a differential pressure presetting device (11) for presetting hydraulic and/or pneumatic control pressure or electrical or mechanical force supplied to the device, where the pressure or the force is independent of a control process of the device. The control pressure is provided as variable control pressure or the force is provided as variable force for obtaining different operation modes of a hydrostatic load sensing drive system. A control piston is adjustable in a housing bore.

Brake control system for mobile working machine, particularly ground conveyor, has braking device, which is formed as spring-loaded brake and works as driving brake and as emergency brake

The brake control system (1) has a braking device, which is formed as spring-loaded brake and works as driving brake and as emergency brake. A short-circuit connection (50,50a,50b) of the brake pressure chamber (7) with the brake release pressure chamber (9) is produced for attainment of the emergency brake function, in which the maximum braking force is determined by a spring unit (8).

Electro-hydraulic precontrol device i.e. electrically operated pressure control valve, for generating hydraulic control pressure to control and actuate actuator device, has control region provided in flow path, where valve has cross-section

The device (V) i.e. electrically operated pressure control valve (10a), has a control region, which is limited to two control positions (15a, 16a), where a control pressure line (13a) is connected to a container line (12a) in one of the control positions and connected to a supply pressure line (11a) in the other control position. The pressure control valve is provided in a flow path (20a) connecting the control pressure line with the container line, and the control region is provided in the flow path, where the valve includes an adjustable throttle cross-section (21a).

Work machine with spring loaded brake and prestressed spring device providing idle travel

Brake device e.g. spring-loaded brake device, for e.g. industrial truck, has pedal force influencing device staying in effective connection with pedal and loadable by brake pressure, where influencing device is designed as piston device

The device (1) has a hydraulically operated brake operating device (2), and a brake pedal (13) staying in effective connection with a brake valve, which produces a brake pressure. A resetting spring device is provided for resetting the brake pedal, where the brake valve is designed as a three-way pressure reducing valve. A pedal force influencing device (20) stays in effective connection with the brake pedal and is loadable by the brake pressure, where the influencing device is designed as a piston device.

Industrial truck

A working machine, such as an industrial truck, having a spring-loaded brake having a braking position and a release position and controlled by a brake valve producing a brake-release pressure. The brake valve is operatively connected to a service brake input device, such as a brake pedal, and can be acted upon in the direction of a reduction in the brake-release pressure arising at the spring-loaded brake when the service brake input device is actuated. It being possible, on actuation, for the service brake input device to be operatively connected to a pre-stressed spring device, which is operatively connected to the brake valve and can be acted upon in the direction of an increase in the spring force on increasing actuation of the service brake input device.

Hydrostatic drive system for use as operating hydraulic system in drive machine i.e. floor conveyor, has pressure gauge pressurized in direction of flow-through position by control signal, and safety device exhibiting safety position

The system (2) has a safety device (20) exhibiting a functional position, in which a control signal is guided to a control valve unit, and a pressure gauge (12) is pressurized by a load pressure signal, where pressurization of the control valve unit is controlled using the control signal. The safety device exhibits a safety position (21a), in which the control valve unit is balanced by the control signal, and the pressure gauge is balanced by the load pressure signal. The pressure gauge is pressurized in a direction of a flow-through position by the control signal.

Hydrostatisches Antriebssystem

Die Erfindung betrifft ein hydrostatisches Antriebssystem (1) mit einer im Fördervolumen verstellbaren Pumpe (2), die zur Versorgung mindestens eines Verbrauchers (V) vorgesehen ist, wobei eine Fördervolumenstelleinrichtung (10) der Pumpe (2) mittels eines Vorgabesignals in Richtung einer Erhöhung des Fördervolumens gesteuert ist und in Abhängigkeit von einem den überschüssig geförderten Volumenstrom der Pumpe (2) erfassenden, hydraulischen Rückstellsignal in Richtung einer Verringerung des Fördervolumens gesteuert ist, wobei zur Erzeugung des Rückstellsignals eine Umlaufdruckwaage (31) vorgesehen ist, die in einer Rückstellsignalerzeugungsstellung (31b) das hydraulische Rückstellsignal erzeugt, wobei zur Steuerung der Fördervolumenstelleinrichtung (10) der Pumpe (2) ein von dem Vorgabesignal beaufschlagbares Stelldruckventil (20) vorgesehen ist. Die Aufgabe, ein derartiges Antriebssystem zur Verfügung zu stellen, bei dem die Pumpe einen geringen Bauaufwand aufweist und eine verbesserte ...

Load-sensing regulated hydrostatic drive system for use in mobile machines such as excavators, construction, forestry, agricultural machinery, trucks or mowers, has pump and controlling valve that is provided for controlling consumer

The load-sensing regulated hydrostatic drive system has a pump (1) and a controlling valve (5a,5b) that is provided for controlling a consumer, where a tapping of a delivery pressure signal is carried out within area of the controlling valve. The delivery pressure signal is forwarded to a regulating valve device (6) of the pump by a delivery pressure signal line (51).

Ventileinrichtung

Ventileinrichtung mit einem Sperrventil, das zwischen einem Einlass und einem Auslass angeordnet und in Strömungsrichtung vom Einlass zum Auslass in eine Öffnungsstellung bringbar ist, und mit einer parallel zum Sperrventil angeordneten Drosseleinrichtung, wobei die Drosseleinrichtung als verstellbare Drosseleinrichtung mit einer Drosselstellung und einer Durchflussstellung ausgebildet ist, wobei ein Steuerdruckaufbau vom Einlass zum Auslass über das geöffnete Sperrventil erfolgt und ein Steuerdruckabbau vom Auslass zum Einlass bei in der Sperrstellung befindlichem Sperrventil über die Drosseleinrichtung erfolgt, dadurch gekennzeichnet, dass die Drosseleinrichtung (3) in Richtung der Drosselstellung (3a) von einer Feder (8) beaufschlagt ist und in Abhängigkeit von dem am Auslass (A) der Ventileinrichtung (1) anstehenden Druck in Richtung der Durchflussstellung (3b) steuerbar ist.

Valve unit has restrictor unit controllable and pressurized by outlet pressure in direction of throughflow position and loaded by adjustable spring in direction of throttling position

The valve unit includes a shut-off valve especially as a check valve (3) installed between an inlet (E) and an outlet (A), a restrictor unit installed parallel to the shut-off valve and provided with a throttling position and a throughflow position. The restrictor unit (3) is controllable in dependence upon the pressure existing at the outlet of the valve unit (1). The restrictor unit is pressurized by outlet pressure in the direction of the throughflow position (3b), and loaded by an adjustable spring (8) in the direction of the throttling position (3a).

Hydrostatic drive system

A hydrostatic drive system has a consumer (7), in particular a hydraulic motor, located in the open circuit. Associated with the consumer (7) is at least one pressure limiting device (11a; 11b) that can be actuated in the braking phase for the generation of a braking pressure that is present on the discharge side of the consumer (7) from a minimum response pressure in the direction of an increase of the response pressure. A feeder device (12a; 12b) provides a feed of pressure fluid into the admission side of the consumer (7). The pressure limiting device (11a; 11b) and the feeder device (12a; 12b) are integrated into a valve unit (10a; 10b).

Industrial truck with spring brake, comprises pre-loaded spring arrangement and pressure reduction valve

The brake valve (8) is activated by a brake pedal creating a reduction of the pressure acting on the spring brake. The pedal acts also in combination with a preloaded spring arrangement (26). A helical spring (30) is positioned between two spring seats (31,32), one of them (31) connected to a control slide (33) of the pressure reduction valve (8a); the opposite seat (32) is connected to the control device of the service brake. An adjusting screw (36) is joined to a threaded bore (35) at the first spring seat (31).

Control valve device for controlling dual acting hydraulic stick cylinder of mobile working machine i.e. excavator, has regeneration valve partially closing pressure medium line, when regeneration valve is in regeneration position

The device (15) has a regeneration device (R) for connecting a return side of a stick cylinder (9) with an inlet side of the stick cylinder. The regeneration device has a regeneration valve (30) i.e. longitudinal slide valve, that is arranged in a pressure medium line (25b), which is guided from the return side of the cylinder to a control valve (20) i.e. directional control valve. The regeneration valve partially closes the pressure medium line, and the return side of the cylinder is connected with the inlet side, when the regeneration valve is in a regeneration position (30a).

Hydrostatisches Antriebssystem mit einer im Fördervolumen verstellbaren Pumpe

Die Erfindung betrifft ein hydrostatisches Antriebssystem (1) mit einer im Fördervolumen verstellbaren Pumpe (2), die zur Versorgung mindestens eines Verbrauchers (V) vorgesehen ist, wobei eine Fördervolumenstelleinrichtung (10) der Pumpe (2) mittels eines Vorgabesignals in Richtung einer Erhöhung des Fördervolumens gesteuert ist und in Abhängigkeit von einem den überschüssig geförderten Volumenstrom der Pumpe (2) erfassenden, hydraulischen Rückstellsignal in Richtung einer Verringerung des Fördervolumens gesteuert ist, wobei zur Erzeugung des Rückstellsignals eine Umlaufdruckwaage (31) vorgesehen ist, die in einer Rückstellsignalerzeugungsstellung (31b) das hydraulische Rückstellsignal erzeugt. Erfindungsgemäß ist einer das hydraulische Rückstellsignal führenden Rückstellsignalleitung (32) eine Druckbegrenzungseinrichtung (50) zugeordnet und/oder ist eine Abschalteinrichtung (70) für das hydraulische Rückstellsignal vorgesehen.

Hydrostatic drive system for working machines e.g. excavators, has load e.g. hydraulic motor which is provided with pressure limiting device whereby pressure limiting device and feeder device are integrated in valve unit

Hydrostatic drive system has a load which is provided with pressure limiting device (11a,11b). The pressure limiting device and feeder device (12a,12b) are integrated in valve unit (10a,10b). The valve unit is formed as a combined pressure limiting and feeder valve. For increasing the reaction pressure, the valve unit stays in active contact with piston unit (20a,20b).

Hydrostatic drive system

A hydrostatic drive system has a pump (1) and at least one consumer (5) controlled by a control valve (4) that can be actuated by control signals. A precharge device (10) that generates a precharge pressure is located in a reservoir line (7) that leads from the control valve (4) to a reservoir (2). The precharge device can be pressurized as a function of the control signals of the control valve (4). To make possible a recharge during the deceleration of a consumer, the precharge device (10) can be pressurized in the direction of an elevation of the precharge pressure when there is a decreasing control signal of the control valve (4).