Knorr-bremse Gmbh

Knorr-bremse Ag

Josef Hintner

Georg Stauble

Peter Pick

Georg Stable

The control device has a key valve (7) with a differential piston (13) and a scanning arm (18) that can be moved by it. The differential piston (13) is charged on its smaller surface (12) by a first brake pressure emitted by the brake control valve (2), and on its larger surface (14) by a reduced second brake pressure derived from the first brake pressure by means of a reduction valve (23, 26), which can be opened by the differential piston (13) only by a motion of a scanning arm (18), corresponding to a vehicle when unloaded, by means of a stop (24). The second brake pressure charges a switching piston whcih shifts the closing point of the reduction valve (23, 26) in the direction of motion of the differential piston (13) for lifting the scanning arm, and switches a shuttle valve (10, 35, 38) which charges a brake cylinder (44) either with the first or the second brake pressure. The volume of the spaces conducting the second brake pressure is increased by an air container (42). The key valve (7) has a very simple construction and, after an initial scanning touch, again lifts the scanning arm (18) during braking of an unloaded vehicle from its abutment (21'), which prevents unnecessary wear and tear.

Load-dependent brake pressure control device for pneumatic brakes of

A pulsating brake accelerating device for an indirectly operating air brake for rail vehicles has a pulsator (12), which is attached to the brake pipe (BP) via a jet (23). The pulsator (12) forms a mixed pressure from two pressures. One of the pressures is formed by the pressure of the brake pipe (BP) via a jet (23) and the other pressure is formed by pressure from a control chamber (QAC) via another jet. At every braking level the pulsator (12) drains mixed pressure pulses off into the atmosphere, while at the same time the brake pipe pressure and the control chamber pressure is lowered via the mixed pressure pulsator (12). The mixed pressure can consist of two valves (14, 15). The control element (4) of the brake accelerator unit can be the emergency brake piston, which monitors several valves, one of which is the pulsator-excitation valve (8).

Pulsating brake accelerator for rail vehicle air brake

A brake accelerator is operable sequentially upon each successive braking stage over the service application range of brake line pressure reductions and is employed with a single release brake control valve of an indirectly acting compressed air brake for railway vehicles. The control valve has a service brake portion and an emergency brake portion provided with a emergency brake piston one side of which is subjected to brake line pressure and the other side is subjected to auxiliary chamber pressure . The accelerator has a main piston which operates an inlet valve to connect the accelerator to the brake line. The main piston which is also subjected on one side to brake line pressure and the other side to auxiliary chamber pressure is moved to a service position upon an application of the brakes to open the inlet valve and connect a control piston with the brake line such that the control piston is subjected on both sides to brake line pressure. The control piston is repeatedly moved between two positions such that quantities of air are cyclically withdrawn from the brake line and the auxiliary chamber to maintain the pressure relationship existing on both sides of the main piston during the service application. The drawing off of air from the auxiliary chamber by the control piston is carried out separately and independently from venting of the auxiliary chamber by the emergency brake piston.

Brake accelerator for a fluid pressure brake system

A brake control device has a selective release accelerator which responds only to a normal release subsequent to an increase of brake line pressure initiated by the operator's brake valve. A first piston has one side subjected to air line pressure and the other side subjected to pressure in an auxiliary reservoir. The first piston controls an inlet valve to connect the emergency reservoir to the brake line. A second piston has one side subjected to brake line pressure and its other side to pressure in the auxiliary reservoir and monitors the first piston. The side of the first piston subjected to auxiliary reservoir pressure is connected through a throttled connection to the auxiliary reservoir when the brake line pressure is smaller than or equal to the auxiliary reservoir pressure. This throttled connection is interrupted when the brake line pressure reaches a predetermined value higher than the auxiliary reservoir pressure.

Brake accelerator device for an air brake system of a railway vehicle

A brake accelerator has a control chamber connected through a throttle orifice to a brake line. The brake system includes a control valve in which is an emergency brake piston one side of which is subjected to brake line pressure and the other side of which is subjected to pressure in the control chamber. The emergency brake piston, as a function of a pressure drop in the brake line, opens a brake line outlet valve so that air flows from the brake line through an inlet valve. The inlet valve is held by a control piston in its open position at the start of a pressure drop in the brake line and the air is flowed into a chamber to form a control pressure. The control pressure acts on the control piston to open an outlet valve for tapping or drawing off the air from the chamber and to close the inlet valve in such a manner that after a predetermined period of time when the pressure in the chamber has dropped below a predetermined value the control piston will be returned by a spring to its initial position so that a limited quantity of pressure fluid is drawn from the brake line by the accelerator.

Brake accelerator for a fluid-pressure brake system having a brake

A brake accelerator for drawing off air from the brake line of an air brake system for railway vehicles has a piston one side of which is subjected to air pressure in the brake line and the other side is subjected to a control pressure in an expansion chamber connected to the brake line through a throttle opening. A first valve is in a connection between the brake line and a pressure accumulation chamber connected to the atmosphere through a second throttle opening. The first valve is actuated by the first piston when the control pressure exerted on the first piston is predominant. A second valve opens subsequently to the first valve and is located in a connection leading from the expansion chamber through a throttle opening to the atmosphere. The second valve is actuated by a second piston loaded by the pressure in the pressure accumulation chamber in the direction to open the second valve against the force of a spring urging the second valve into its closed position.

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Munich, Germany

Josef Hintner