Abstract: A brake actuating device has an actuator functionally connected between a piston and a brake pedal lever. The actuator is capable of varying the path length of a force-conducting connection between the brake pedal lever and the piston of the brake cylinder via a displaceable element. A spring element acts on the brake pedal lever. The spring force varies during the variation of the path length such that a sum of the spring force and a force acting on the brake pedal lever from the brake cylinder remains essentially unchanged. The spring element is fastened with one end to the displaceable element and with the other end to the brake pedal lever with the interposition of a tensioning mechanism, which is guided by a cam track provided on the brake pedal lever.

Abstract: An adjusting element with a closed first end, a cylinder, a piston displaceably arranged in the cylinder that divides the cylinder into a first work space remote of the first end and a second work space in proximity to the first end, and a piston rod which is arranged at one side of the piston and which projects through the first work space and is guided out of the cylinder concentric to or center longitudinal axis of the cylinder at a second end opposite from the first end so as to be sealed by a guiding and sealing device. The adjusting element has a device for detecting the piston rod position and/or the extended length of the adjusting element. The device for detecting the piston rod position includes a microswitch arranged at the cylinder and at least one switching element cooperating with the microswitch.

Abstract: A manual control mechanism for a lift unit having a lift arm and a hydraulic cylinder for lifting the lift arm up and down. The mechanism includes a control valve configured as a three-position switchover valve for selectively providing lowering, neutral and elevating conditions according to a spool position for controlling movement of the hydraulic cylinder, a lift lever for manually operating the control valve and an operational path for guiding operational displacement of the lift lever. The operational path includes an inching operational path for operating the hydraulic cylinder at a creeping speed by slightly opening a port of the control valve and a main operational path for operating the control valve over an entire stroke range thereof. An operational feel when the lift lever is operationally displaced along the inching operational path is different from an operational feel when the lift lever is operationally displaced along the main operational path.

Abstract: The invention concerns a steering valve with a closed center for supplying an actuator with hydraulic pressure, the steering valve comprising an input shaft, and output shaft, a torsionally resilient element which is connected at one end to the input shaft and at the other end to the output shaft, a control pressure switching arrangement and a torque/axial force conversion unit. A spring loaded seat valve is located in a bore of the input shaft, and closes a fluid passage passing through the torsion tube. The torque/axial force convertor opens the seat valve when relative twisting of the input shaft with respect to the valve casing occurs. According to the invention, in order to improve the response dynamics of such a steering valve, the valve comprises at least one axial bore for supplying hydraulic pressure. At one end this bore is closed by a valve which is loaded by the torque/axial force conversion unit against the hydraulic pressure.

Abstract: This invention relates to a rotary slide valve (5, 6) with a centering device (25) that is loaded by the force of a spring (31). The centering device is placed inside the valve housing (1) without any need for additional space in radial direction. In addition, the reaction pressure required by the steering system is reduced. According to the invention, spring (31) presses upon a reaction piston (32) that acts with a centering piece (24) upon the roller body (30) of the centering device (25). Between a lid (35) and the reaction piston (32), there is a reaction chamber (37) that can be provided with a variable pressure. At faster driving speeds, a pressure supporting spring (31) in the reaction chamber (37) acts upon the face (41) of the reaction piston (32). In this way, a smaller spring can be used and construction space can be saved because the force of the reaction pressure is additive with the force of the spring (31).

Abstract: In order to be able to adjust the distance between a reaction disc and a second part of a a two-part valve piston interacting with the former in a completely assembled vacuum brake power booster, a tubular sleeve is provided according to the invention which is disposed coaxially with a piston rod actuating the valve piston, which is axially slidable and which is engageable with a first part of said valve piston being coupled to the second part by means of a threaded union in order to apply a torque to the first piston part.

Abstract: A method of controlling a cylinder apparatus includes the steps of supplying compressed air of a first high pressure to one chamber of a cylinder which is divided into two chambers by a piston, and exhausting air from the other chamber so as to move the piston from the start position at an end portion of one chamber toward an end position at an end portion of the other chamber along the extending direction of the cylinder, and detecting if the position has passed the position of a sensor. In addition, a moving speed of the piston is decreased by supplying air of a second high pressure lower than the first high pressure to the other chamber after an elapse of a predetermined wait time from when the piston has passed the position of the sensor, so that the piston reaches the end position in a shock-free state.

Abstract: A device for limiting a working stroke of a hydraulic cylinder has a working cylinder and a working piston comprising a hollow piston rod connected to its top portion. A pressure reservoir is connected to a first working chamber for constantly supplying a pressure medium thereto, and a pressure source is connected via an inlet line to a second working chamber for supplying a pressure medium thereto. A shut-off valve comprises a push piston and a return spring for holding the push piston in its closed position. A drag link is slidably connected inside the push piston and extends through the working piston into the interior of the hollow piston rod. One end of the drag link has a first abutment that comes into contact with the working piston before the working piston reaches its end position.

Abstract: An assembled brake booster, including a method of adjusting a jump value of the booster, in which a load on a valve spring (38) is adjusted by varying the position of a threaded sleeve (50 ) along the control rod (30).

Abstract: A system for positioning equipment quickly and accurately over a plurality of desired positions by employing a "long move" mode of operation and a "short move" mode of operation to adapt the operation of the positioning system to variable and changing conditions. The system generally includes a microprocessor as the controlling means, a controlled valving means, a pressure source coupled to the valving means, an encoder sensing means and a positioning means defined by a pneumatic cylinder.

Abstract: A hydraulic drive system for a machine element performing in one work cycle a sequence of motions comprising a rapid feed motion, a working stroke under load and an oppositely directed rapid-return motion. The drive element includes a hydraulic cylinder having three working surfaces A.sub.1, A.sub.2, A.sub.3. Motion control is effected by an electro-hydraulic follow-up control valve with a pre-setting device controlled by a stepping motor and a mechanical actual-value feed-back device. During rapid feed motion, the relatively small working surface A.sub.1 is subjected to the output pressure of the follow-up control valve only, while during the working stroke the pressure acts additionally on the working surface A.sub.3. The rapid-return movements of the piston of the cylinder are controlled by applying pressure to the working surface A.sub.2, or by relieving pressure from the two other working surfaces A.sub.1 and A.sub.3.

Abstract: A pneumatic booster including a housing, a power piston partitioning the interior of the housing into a front chamber and a rear chamber, with the front chamber being connected permanently to a source of a first reference pressure, the rear chamber being selectively communicated with the front chamber and a source of second reference pressure which is higher than the first reference pressure through a valve mechanism, an output shaft receiving the output force from the power piston, and an input shaft receiving an input force for actuating said valve mechanism and receiving a reaction force of the output force. There are provided a device between the output shaft and the power piston for changing the reaction force with respect to the output force on the output shaft, a mechanism for rotating the output shaft around the axis thereof, and a device for preventing the rotation of the power piston relative to the housing at least at the non-actuated condition of the pneumatic booster.

Abstract: A device for adjusting the rotating angle of a vessel of a dump truck which includes a detent having a guide recess, which is pivotally connected to the vehicle body said detent being connected to a spool of a control valve operated by an operating lever. An arm is pivotally connected to the vehicle body and has a cam follower journaled therein, and another arm is secured to the rod of a cylinder and has a bolt which is secured to said another arm and is adjustable in height. Thus, the shock is absorbed when the vessel is travelling upwards and is stopped.