Fluid-pressure and analogous brake systems – Releasing – Motor
Reexamination Certificate
2001-05-04
2002-04-23
Butler, Douglas C. (Department: 3613)
Fluid-pressure and analogous brake systems
Releasing
Motor
C303S003000, C303S015000
Reexamination Certificate
active
06375277
ABSTRACT:
FIELD OF THE INVENTION
The invention generally relates to manually operated valves that heretofore have been used only on freight railcars equipped with conventional pneumatic brake control valves to vent air from the brake cylinders. More particularly, the invention pertains to a release valve apparatus designed for freight railcars equipped with electrically controlled pneumatic (ECP) brake control valves.
BACKGROUND OF THE INVENTION
The following background information is provided to assist the reader to understand at least one of the many environments in which the invention could be used. The terms used herein are not intended to be limited to any particular narrow interpretation unless expressly stated otherwise in this document.
A freight train typically includes one or more locomotives, a plurality of railcars and several trainlines. For a freight train headed by a locomotive equipped with an ECP brake control system, the trainlines include both pneumatic and electrical lines some of which run from the lead locomotive to the last railcar in the train. A pneumatic trainline known as the brake pipe is one such trainline. It extends the length of the freight train, as does a two-wire electrical trainline known as the ECP trainline. Each locomotive also features a multi-wire electrical trainline known as the multiple unit (MU) line cable. The MU line cable consists of 27 different electrical lines. As is well known in the railroad industry, the MU line cable contains 74V dc power and return lines on which battery power from the locomotive is supplied to the ECP brake equipment on each railcar and to various other power consuming devices on the train.
The brake pipe consists of a series of pipe lengths, with one pipe length secured to the underside of each railcar. As shown in
FIG. 1
, each pipe length has, at each of its ends, a flexible hose
1
with a coupler commonly referred to as a glad hand
2
. As the locomotives and other rail vehicles are coupled in sequence to form the freight train, the brake pipe
3
is formed by connecting the glad hand
2
at the end of each pipe length to the glad hand
2
of another such pipe length on an adjacent vehicle. Similar to the brake pipe
3
, the conduit in which the ECP trainline
4
is housed actually constitutes a series of individual conduits. One such conduit secured to the underside of each vehicle interconnects to another such conduit via a connector between each rail vehicle. Supplied from the 74V dc power line of the MU line cable in the locomotive, the ECP trainline
4
typically operates at a nominal 230V dc to power the ECP brake equipment on each railcar of the freight train.
The ECP brake control system in the locomotive includes a cab station unit and a master controller from which the brakes on the train are ultimately controlled. The cab station unit features one or two handle(s) and/or push buttons that the train operator uses to direct control of the brakes. One such handle, known as the automatic brake handle, can be moved to and between the following positions: release, minimum service, full service, suppression, continuous service, and emergency. Between the minimum and full service positions lies the service zone wherein each incremental movement of the handle toward the full service position causes an even stronger service application of the brakes. The force with which the brakes apply depends on how far towards the full service position the brake handle is moved.
Inputs from the handle(s) and/or push buttons are processed by the cab station unit and then passed to the master controller. Operating according to instructions contained within its programming code, and in response to the inputs from the handle(s) and other sources, the master controller formulates a brake command appropriate to current conditions and transmits it along the ECP trainline
4
to each railcar in the freight train. As specified by the American Association of Railroads (AAR), the brake commands and other ECP messages are transmitted from the locomotive using a powerline communications system such as the Echelon LonWorks System. Along the ECP trainline
4
, the brake command(s) are then conveyed to the ECP brake equipment on each railcar via branch wiring
5
. Similarly, in a manner known in the railroad industry, the brake pipe
3
connects to the ECP brake equipment on each railcar via a branch pipe
6
.
The master controller can thus order, through the brake command, any action from a release of brakes to an emergency application of brakes or any degree of brake application in between those two extremes. The brake equipment may also be designed to provide graduated release of the brakes. The degree of brake application ordered by the master controller is typically conveyed in terms of a percentage of the pressure required for full service brake application. For example, zero percent (0%) is typically designated for a release of brakes, 15% for a minimum service brake application, 100% for a full service brake application and 120% for an emergency brake application.
The ECP brake equipment on each railcar typically includes an auxiliary reservoir
10
, an emergency reservoir
20
, one or more brake cylinders
30
, a retainer valve
40
, a car control unit (CCU)
50
and an ECP brake control valve, generally designated
60
. The ECP brake control valve
60
includes a pneumatic portion
61
and an electropneumatic portion, generally denoted
63
, typically mounted to opposite sides of a pipe bracket
62
. The pneumatic portion may take the form of an emergency portion of a brake control valve such as an ABD, ABDX or ABDW type valve made by the Westinghouse Air Brake Technologies Corporation (WABTEC). The electropneumatic portion
63
is comprised of a manifold
100
, several pressure transducers, and several solenoid-operated application and release valves. The transducers and solenoid valves are collectively designated by section
200
. The manifold
100
defines several ports to which the transducers and solenoid valves connect. It also defines a number of internal passages, which communicate with passages internal to the pipe bracket
62
.
Each port of the pipe bracket
62
connects to one of the interconnecting pipes on the railcar such as those leading to the brake pipe
3
, the retainer valve
40
, the auxiliary reservoir
10
, the emergency reservoir
20
and the brake cylinder
30
. It is through the internal passages of the pipe bracket
62
that the various portions of the brake equipment communicate fluidly with the pneumatic piping on the railcar. Used to monitor the pressures in the brake pipe
3
, the two reservoirs
10
and
20
and the brake cylinder
30
, the pressure transducers convey electrical signals indicative of those pressures to the CCU
50
.
Each CCU
50
includes a transceiver and a microprocessor. Controlled by the microprocessor, the transceiver is connected via the branch wiring
5
to the ECP trainline
4
from which it receives the brake commands issued by the master controller. The transceiver converts the electrical brake commands into a form usable by the microprocessor. Operating according to its programming code and to the dictates of the brake commands and other electrical signals it has received, the microprocessor controls the application and release valves in a manner well known in the brake control art. It is through the solenoid valves that air can be maintained within, exhausted from, or directed from either or both of the reservoirs to the brake cylinder(s)
30
.
By moving the automatic brake handle into service zone, for example, the train operator in the locomotive will cause the ECP brake control system to issue a service brake command along the ECP trainline
4
. In response to the service brake command, the microprocessor on each railcar will then energize the application valve(s) for the appropriate time. This enables the appropriate amount of air to flow from the auxiliary reservoir
10
and/or the emergency reservoir
20
via the pipe bracket
62
and the manifold
100
throug
Butler Douglas C.
Westinghouse Air Brake Technologies Corporation
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