Westinghouse Brake and Signal Company Limited

Other

Westinghouse Brake & Signal

David J Wickham

Jack Washbourn

Howard F Cogan

Clive A Rathband

Raymond A Wilkins

Edmund J Page

A spring applied force actuator having an output member movable from a first position to a second output position, a first power spring by which can be generated on the output member an output force when the member is in its second position, first power means by which potential energy can be generated in the first spring therein to be held until the spring is released to apply its stored force as an output force on the output member, a second spring release of potential energy stored in which moves the output member from its first position to its second output position, and second power means by which the output member can be moved back from its second output position to its first position thereby, at the same time, generating in the second spring the potential energy subsequently to move the output member back to its second output position upon the subsequent release of that second spring.

Electric actuators

An electrically-controlled force-exerting actuator comprising a force-applying power spring arranged to exert a force on an output member, a force-applying control spring arranged with respect to the power spring such that the force exerted by the control spring is detracted from the force exerted by the power spring to determine the residual force exerted on the output member by the power spring, and an electric motor operable to vary the detractive force exerted by the control spring.

Electrically-controlled actuators

An electric actuator having an electric motor operable to determine the output force generated on an output member by a spring; a drive shaft arranged to be driven by the electric motor and having first and second drive means, a non-rotational but axially movable intermediate member which is threadedly engaged with first driven means arranged to be driven by the first drive means; the spring being located between the intermediate member and the output member and arranged so that axial movement of the intermediate member is transmitted to the output member so long as the latter is free to move and, when the output member is restrained from movement, generates the output force on the output member upon continued operation of the electric motor; a stop carried by the intermediate member and positionally adjustable with respect thereto in the direction in which the intermediate member is axially movable, and second driven means with the second drive means, the first driven means being engageable with the stop to arrest its rotation and, hence, through the second drive means, to arrest further operation of the electric motor in its direction to increase the output force generated on the output member.

Electrical circuit configurations are described for the operation of an electrically powered actuator in an emergency to drive the actuator to a predetermined position. In particular the actuator is connected to apply friction brakes of a railway vehicle. The configurations have in common are emergency power circuit connected between an emergency power source and the actuator, means for breaking the power circuit when the actuator reaches the emergency position and latching means to prevent run-back. Preferably and in order to minimize size and weight the emergency power source is of limited capacity, sufficient for, say, two such emergency applications and is recharged from a normal power supply; the recharging circuit being interlocked with the latching means such that the actuator may not be released from the emergency position unless the power source has sufficient charge for at least one further emergency operation.

Actuator emergency operation

A control valve arrangement adapted to produce and maintain a pilot signal comprises a number of standard modules. The basic element has two standard modules, each of which includes a diaphragm-controlled on-off valve. An input signal is applied to a first valve against a reference pressure such that when the valve is on, a signal is generated and held as a pilot pressure. A second valve responds to a fall in input signal pressure to cancel out pilot pressure. The two valves together constitute a bistable operator. A particular use of this operator is in a railway braking system in which the first valve is used as an application valve and the second valve is used as a release valve. A third module may be used as a pilot pressure-maintaining valve. The pneumatically-operated diaphragm assembly shown in FIG. 1, comprises three modules, 1, 2 and 3. Module 1 is the brake application module, module 2 is the release module and module 3 is an optional pilot pressure-maintaining module. Each module includes a ball valve 8, 21, 30, operated by respective diaphragms 5, 19, 26. Modules 1 and 2 act as a bistable operator producing the pilot pressure and module 3 acts to maintain the pilot pressure.

Control valve arrangement

An empty-load railway vehicle braking system wherein the piston-and-cylinder of the empty-load valve operates against the rack of a rack-and-pinion arrangement of which the pinion is drivingly connected to an arresting member the position of which is determined by the loading of the vehicle.

Braking systems for railway

An electric actuator having an electric motor operable to determine the output force generated on an output member by a spring system, and an adjustable stop by which can be limited the maximum value of the output force, the position of the adjustable stop being variable in accordance with variation of the required maximum value of the output force to be exerted by the output member.

The present invention provides an electric actuator having an output member movable from a first variable position to a second variable position; an electric motor operable to control a spring system to exert an output force on the output member when in its second position; a device for generating an electrical signal when the output member is about to leave the second position as it returns to the first position; and a motor-control electrical circuit which recognizes the generation of the electrical signal and thereafter operates the electric motor to a pre-determined degree to move the output member a corresponding pre-determined distance back to the first position so that there is preserved a substantially constant distance between the first and second positions.

This invention relates to a valve assembly for a railway braking system, including a brake cylinder pressure-maintaining valve which, during brake application, takes air from the brake pipe and feeds it into the brake cylinder until it reaches minimum brake pressure. To avoid the need for an extra valve, the brake cylinder pressure-maintaining valve is used as a quick service bulb exhaust valve during brake release and member are provided to ensure that the brake cylinder pressure maintaining valve opens immediately on brake release. Once the brakes have been applied, pressure in the brake cylinder is maintained from the quick service bulb 59. Brake cylinder exhaust pressure taken from a point 124 after the brake cylinder exhaust valve 50, but before the brake cylinder exhaust choke 70, is directed to chamber G above the inshot and brake cylinder-maintaining valve diaphragm 131. Since the pressure in port 124 upstream of the brake cylinder exhaust choke 70 attains a pressure well within 10 p.s.i. of chamber H, the spring 67 in chamber G can open the brake cylinder maintaining valve 64. Thus, immediate opening of brake cylinder-maintaining valve 64 occurs when the bi-stable operator moves to the release position. Bulb pressure from QS bulb 59 is then able to flow via the BC maintaining choke 65 and fall with the fall of brake cylinder pressure in port 120.

Combined BC pressure-maintaining valve and quick service bulb exhaust

This invention relates to braking systems for railway vehicles in which a fall in brake pipe pressure is employed to initiate braking via a brake cylinder inlet valve. In accordance with the present invention, the brake cylinder inlet valve is rendered in-operative by the absence of auxiliary reservoir pressure, thus dispensing with the need for a complicated mechanical sequence requiring fine machining tolerances etc. and avoiding the necessity of employing an additional valve. The brake cylinder (BC) inlet valve 60 is operable by a diaphragm 54. When the system is fully charged, the brake cylinder inlet valve 60 is closed as shown in the accompanying drawing. The diaphragm 54 is subject to brake pipe pressure in chamber C and to auxiliary reservoir pressure in chamber D. In the absence of auxiliary reservoir pressure in chamber D, the pressure in chamber C holds the diaphragm in the position shown and prevents the ball valve 60 from being opened, thus preventing brake application until braking is demanded.

Braking cylinder inlet valve arrangement in braking systems for railway

This invention relates to a railway braking system in which a drop in brake pipe pressure calling for brake application initiates a pilot pressure and this pilot pressure is used to operate other valves pneumatically to effect braking. In this system, during the initial part of a brake application, air flows to atmosphere through a pilot exhaust choke. To avoid problems during release of the braking, it is proposed to isolate or restrict this pilot exhaust choke during at least the initial part of the brake application stage. To achieve this, an interlock valve is introduced into a passage between a release ball valve and a pilot exhaust choke. The interlock valve is operated by a diaphragm biassed by a spring and separating two chambers. Brake pipe pressure is applied to the first chamber and auxiliary reservoir pressure to the second chamber. A very small drop in brake pipe pressure closes the valve and cuts off connection between the release ball valve and the pilot exhaust choke.

Interlock valve for railway braking system valve assembly

Empty/load control valve apparatus is proposed for use with direct release triple valves which operate by switching in an extra volume with the brake cylinder for empty loaded conditions. This improvement provides a valve operated in response to leakage away of brake cylinder pressure to enable dissipation also of the extra volume pressure to prevent brake cylinder isolation resulting from the extra volume pressure.

Empty/load brake control valve apparatus

A rail vehicle braking apparatus which operates with brake control valves on successive vehicles of a train controlled by pressure in a brake pipe extending along the train has warning means responsive to rising brake pipe fluid flow to warn of possible non-released brakes in the train and the warning means being inhibited by a rising fluid pressure-sensing means to prevent an undesired warning due to brake pipe fluid flow during release of the brakes.

Rail vehicle braking apparatus

A floatable toy has a body which even when filled with water is inherently buoyant, has an aperture for readily filling with water and when floating in the level of the water within is higher than the level of surface upon which the body floats and having restrictive flow passages from the interior to the exterior to below the surface to produce rotational or other movement.

Buoyant device with means for producing thrust

The invention concerns an electrically assisted pneumatic train braking system. In a normal emergency/service pneumatic braking system a pneumatic pressure change must propagate along the train braking system from car to car. The present system includes two valves which are connected to each end of the brake pipe of each car, the first is responsive to a pressure change in the brake pipe to produce an electrical signal and the second being responsive to the electrical signal to produce a pressure change in the brake pipe. Thus, the propagation time for the whole braking system is reduced to little more than that for the total length of the couplings between cars.

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Chippenham, United Kingdom

David J Wickham