Patent Application
20110006595
The present disclosure relates generally to automatic hand brakes and more specifically to a control system for automatic release of hand brakes.
Hand or parking brakes on rail vehicles generally include a chain connected to the vehicle brakes and wound around a wheel. The brakes are applied by rotating the wheel and tensioning the chain. The hand brake includes a trigger or lever which, when activated, automatically releases the tension on the chain and releases the parking hand brake.
Two cylinders may be provided on the hand brake to apply the brakes by turning the wheel to tension the chain and a second cylinder to release the brakes by interacting with the release trigger or lever. A pneumatic system to control the two cylinders manually is illustrated in U.S. Pat. No. 6,394,559, for example. The use of parallel manually actuated valves and electro-pneumatic valves is described in U.S. Pat. No. 7,014,275. The actuation of the electro-pneumatic valves as discussed herein may be by an electrically controlled pneumatic (ECP) brake network and through the cars control unit (CCU). The overall control system is described, for example, in U.S. Pat. No. 7,073,753.
Remote control of the hand brake by hand-held terminal is described in U.S. Pat. No. 6,175,784.
The present hand brake control system for a rail vehicle hand brake having a release trigger includes a cylinder for activating the release trigger of the hand brake and a source of pressure. A first valve selectively connects either the source of pressure at a first input or a second input to the cylinder at an output. A second valve selectively connects either the source of pressure or exhaust to the second input of the first valve at the output of the second valve. The first valve may be a manually operated valve and the second valve may be an electro-pneumatic valve.
The first valve is a manually operated valve having a stable position connecting the second input of the first valve to the output of the first valve and a manual operated position connecting the first input of the first valve to the output of the first valve. The first valve has a manually operated rocker mechanism.
Linkage may be connected to the first valve and extends to at least two locations about the sides of the vehicle for manual operation of the first valve without mounting the vehicle.
The second valve has a stable position connecting exhaust to the second input of the first valve and an activated position connecting the source of pressure to the second input of the first valve.
The source of pressure may be a reservoir on the vehicle or a source of pressure off the vehicle connected by a tap. A check valve between the source of pressure and the first and second valves pre-charges the connection to the first and second valves.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.
A control system for automatic release of a hand brake is illustrated in
The source of pressure in line 20 is connected to a first input 32 of a first valve 30. The first valve 30 is illustrated as a manually operated valve. A second input 34, normally connected to exhaust or atmosphere is provided on the valve 30. The output 36 of valve 30 is connected to the cylinder 10. Spring 38 biases the valve 30 in the shown position where the supply pressure at input 32 is not connected to the brake release cylinder. In this position, the release cylinder 10 is exhausted through connection 34. This is a stable position of the first valve 30.
The manual operator 40 of the valve 30 is connected at joint 42 to links 44. Links 44 extend to the exterior of the vehicle allowing access at various points for manual operation at various points adjacent to the vehicle without mounting the vehicle. As shown in
A second valve 50 is illustrated as an electro-pneumatic valve. The first input 52 is connected to the pressurized supply line 20. A second input 54 is connected to exhaust or atmosphere. The output 56 is connected to the second input 34 of the first valve 30. Spring 58 biases the valve 50 in the position shown, wherein the connection to the supply line 52 is terminated and exhaust at input 54 is connected to its output 56 and input 34 of valve 30. Thus, in the stable position shown of the two valves 30 and 50, the release cylinder 10 is deactivated. By connecting valve 50 between the exhaust EX and the input 34 of the valve 30, any system leaking is allowed to go to exhaust. This prevents undesired release of the hand brake.
For manual actuation using the link or release rod 44 and actuator 40, the valve 30 is moved to its applied position connecting the pressurized supply at input 32 to its output 36 and cylinder 10. This activates cylinder 10, activating the release trigger and releasing the hand brake. Once the operator releases the linkage 44, the spring 38 causes the valve 30 to move to its stable position, cutting off the supply of air to the cylinder 10 and connecting the cylinder 10 through valves 30 and 50 to exhaust.
The electro-pneumatic valve 50 may be actuated by an electric signal from its stable position shown to a second position. This connects the pressurized supply at input 52 to its output 56. This is provided directly through input 34 to output 36 of valve 30. This activates the cylinder 10 which moves the brake release trigger or lever. Upon removal of the signal, spring 58 moves the valve 50 back to the position shown, connecting the cylinder 10 via valve 30 and 50 to exhaust and input 54 of valve 50.
The valve 50 may be connected to an ECP car control device CCD which is connected to a train line and activated upon receiving a hand brake release signal from the locomotive. Providing such system is described in U.S. Pat. No. 7,073,753 and is incorporated herein by reference. Alternatively, the valve 50 may be actuated by a hand held device carried by operator as he walks the train. Such a device is shown, for example, in U.S. Pat. No. 6,175,784.
An example of the manually operated valve 30 is shown in detail in
Although valve 30 shown in
Releasing the hand brake by means of the present system has clear advantage over current means. The hand brake is generally located at one end of a freight car. It is installed off-center of the car axis and is accessed by a short ladder, so the operator of the handbrake stands on the ladder attached to the car. In this way, if the car or train moves suddenly, the operator moves with the car. Standing on the ground between the cars is clearly unsafe. Although other arrangements address the safety issue of working between the cars, it does not address the safety issues related to climbing a ladder on the end of the car and operating the handbrake while on the ladder. In addition, due to the non car-axial installation location of the handbrake on the car, the hand brake can only be accessed from one side of the car. As cars can be oriented in either direction in a train, releasing all the handbrakes on a train requires that a crew walk both sides of the train.
The present system addresses both limitations of current technology. The release rod, 44, can be actuated from either side of the car, while standing on the ground. By this means the operator avoids both the hazards associated with being position between the cars, and the hazard associated with climbing and working while on the access ladder. In addition, productivity is improved, as all the handbrakes on the train can be accessed from one side of the train, regardless of car orientation. The manually operated valve 30 with the release rod 44 may be used without the second valve 50.
Although the present hand brake control system has been described and illustrated in detail, it is to be clearly understood that the same is by way of illustration and example only, and is not to be taken by way of limitation. The scope of the present invention is to be limited only by the terms of the appended claims.
