A system for retarding the speed of a railcar comprises a brake; a hydraulic actuator moving the brake between a closed position in which the brake applies braking pressure on the wheel of a railcar, and an open position in which the brake does not apply braking pressure on the wheel of the railcar; a hydraulic circuit provided with a pump arrangement for supplying hydraulic fluid to the hydraulic actuator; and a control circuit coupled to the hydraulic circuit for controlling the flow of hydraulic fluid to move the brake between the closed and open positions.

A disk brake arrangement includes a retraction mechanism for positively retracting brake pads after application to the brake rotor. Preferably the retraction mechanism is energized by movement of a hydraulically actuated piston for applying one or more brake pads. In an embodiment a drag sleeve is associated with the piston to compensate for brake pad wear and provide a more constant retraction force for retraction of the brake pads.

A disk brake arrangement includes a retraction mechanism for positively retracting brake pads after application to the brake rotor. Preferably the retraction mechanism is energized by movement of a hydraulically actuated piston for applying one or more brake pads. In an embodiment a drag sleeve is associated with the piston to compensate for brake pad wear and provide a more constant retraction force for retraction of the brake pads.

The present invention provides a rotation limiting device. The rotation limiting device includes a base; a rotator capable of rotating relative to the base; and a rotating shaft slidably connected between the base and the rotator. A spiral groove is provided on one of the base and the rotator, and a stripe groove opposite to the spiral groove is provided on the other one of the base and the rotator, two ends of the rotating shaft are slidahly connected respectively in the spiral groove and the stripe groove, and the rotator is rotated to cause the rotating shaft to slide from starting positions of the spiral groove and the stripe groove to terminal positions of the spiral groove and the stripe groove, such that a rotation angle of the rotator is greater than 360.

A door component has a damper device with two connection units that can be moved relative to each other for damping a door movement of a door of a vehicle. The damper device contains a magnetorheological fluid, as an operating fluid, and a cylinder unit having a first chamber and a second chamber. The two chambers are separated from each other by a piston which is provided with a damping valve. The damper device has a connection which is constructed for coupling to a drive. The damper device can be moved in an active manner at least from a first position into a second position by the drive which is coupled via the connection.

An anti-torsion device of a solar tracker with a rotation axis, and solar tracker comprising the anti-torsion device, the device having a coupling part fixedly attached rotationally with respect to the rotation axis of the solar tracker; an extension element arranged mechanically and fixedly attached to the coupling part, further extending radially and externally with respect to the coupling part; and, an actuator and a counter-actuator arranged in a locked position, where they are in contact with the extension element, and a released position, where they are separated with respect to the extension element, when the anti-torsion device is fixedly arranged with respect to the rotation axis and in accordance with the locked position, the extension element is rotationally immobilized so that the rotation of the coupling part is further prevented.

A disk brake arrangement includes a retraction mechanism for positively retracting brake pads after application to the brake rotor. Preferably the retraction mechanism is energized by movement of a hydraulically actuated piston for applying one or more brake pads. In an embodiment a drag sleeve is associated with the piston to compensate for brake pad wear and provide a more constant retraction force for retraction of the brake pads.

A disk brake arrangement includes a retraction mechanism for positively retracting brake pads after application to the brake rotor. Preferably the retraction mechanism is energized by movement of a hydraulically actuated piston for applying one or more brake pads. In an embodiment a drag sleeve is associated with the piston to compensate for brake pad wear and provide a more constant retraction force for retraction of the brake pads.

A door component has a controllable damping device and contains a magnetorheological fluid. Two connection units are movable relative to one another. One of the two connection units is connected to a support structure and the other one to a pivotable door unit. The device damps a movement of the door unit between a closed position and an open position in a controlled manner by way of a control unit. The magnetorheological damping device has a piston unit and a cylinder unit surrounding the piston unit. The piston unit divides a cylinder volume into two chambers. The piston unit is equipped with a first one-way valve. The two chambers are connected together, via an external return channel equipped with at least one controllable magnetorheological damping valve, to form a one-way circuit. When the piston unit moves in and out, the magnetorheological fluid flows through the piston unit in the same flow direction.

A method for damping a movement of a door system of a vehicle that is equipped with a damping system having an adjustable and controllable damping action. A movement of the door system between a closed position and an open position is damped in a controlled manner. A measurement of the change in speed of the speed of movement of the door system is calculated and if the change in speed exceeds a predefined limit value, a set, gentle damping action is changed over to a greater damping action.