Patent Application
20140332328
Not Applicable.
The invention relates generally to railroad cars and, more particularly to an apparatus and method for releasing a railroad car handbrake.
Generally, two sets of brakes are employed on a train to stop and secure the railcars in place. The main brake system is an airbrake system. On railcars, an air brake is a conveyance braking system actuated by compressed air. Modern trains rely upon a fail-safe air brake system that is based upon a design patented by George Westinghouse on Mar. 5, 1872. In various forms, it has been nearly universally adopted. In general, the Westinghouse system uses air pressure to charge air reservoirs (tanks) on each car. Full air pressure signals each car to release the brakes. A reduction or loss of air pressure signals each car to apply its brakes, using the compressed air in its reservoirs.
The second type of brake employed on a railcar is a manual hand brake assembly that usually includes a relatively large, rotatable hand wheel disposed in a vertical plane and mounted on a shaft which, through a gear train, can rotate a chain drum to wind up a chain that is secured at its end remote from the chain drum to the brake rigging of the railway car. As the hand wheel is rotated in one direction, the brakes are applied and rotation of the hand wheel shaft in the opposite direction is prevented by a holding pawl which engages a ratchet wheel on the hand wheel shaft. The hand brake usually includes a release lever that disengages the holding pawl so that the hand wheel shaft rotates in the opposite direction to disengage the brakes. Each railroad car employs one hand brake at one end of the car or two hand brakes, with one at each end of the car.
If the hand brakes are set and not properly released, generally through inadvertence, the railroad car is pulled without the wheels turning such that the wheels are dragged along the rails, causing damage to the brake system, the wheels and to the rails. This is a dangerous and condition. Furthermore, the damage to the railroad cars and rails is very expensive to repair.
Various systems for releasing the hand brakes have been devised. One example is disclosed in U.S. Pat. No. 5,469,941 to Horvath, which is incorporated herein by reference. Horvath discloses a system that operates off the main air brake pressure lines to automatically release the hand brakes when the air pressure of the train is brought up to a certain level. However, the disclosed system is a “add on” system and is not a fully integrated automated hand brake. The system still requires a manual reset and requires the presence of a release lever.
It would be advantageous, therefore, to have a fully integrated, automated hand brake system that does not require manual reset or a conventional manual release lever.
Briefly stated, an automatic hand brake system for a railcar that comprises a release mechanism operatively connected between an actuator and the spool gear that is turned by hand to set the hand brake. The actuator is operatively connected to a pressured fluid system. When a threshold pressure is reached the actuator operates the release mechanism to release the spool gear so that the brakes are released. When there is a pressure drop, an automatic reset apparatus resets the release mechanism so that the hand brake can set. In one aspect, the pressurized fluid system is an air brake system. In another aspect, the pressurized fluid system is oil or hydraulic system or a combination of air and oil.
In another aspect of the invention, a manual lever can be employed to allow manual release of the hand brake if desired.
In one aspect, all of the operative elements of the release mechanism are contained in the hand brake housing.
In another aspect of the invention, the release mechanism is actuated at a fluid system pressure of less than about 70 psi.
In another aspect of the invention, the release mechanism is actuated at a fluid system pressure of about 30 psi to about 50 psi.
In another aspect of the invention, the mechanism incorporates a permissive that permits the operator of the train, for example the engineer, to allow the release all the hand brakes on all the cars at one time.
In general, the automatic brake release system is designed for the automatic releasing of all hand brakes of a railroad car system. The hand brake can employ many of the internal components of a standard hand brake. Representative internal components are disclosed in U.S. Pat. No. 5,469,941 to Horvath, U.S. Pat. No. 6,364,428 to Labriola et al and in Kanjo's U.S. Application No. 2008/0223669, all of which are incorporated herein by reference. The automatic brake release system can be based on a vertical wheel hand brake or can be employed in other in other types of hand brake systems such as double sided, release and hold and lever type hand brakes.
The hand brake system of the present invention requires only one fluid flow line to operate. The brake system can optionally include a hand lever to manually disengage the brake as well.
The release mechanism is powered from a pressurized fluid source, such as the main air brake pressure lines of the railcars. However, other pressurized fluid systems such as hydraulic systems or a combination of hydraulic and air can be used. In one embodiment, the pressure built up in the lines is used to release the railcar brake by energizing an air cylinder inside the hand brake. The air cylinder actuates the release mechanism to release the hand brake. When pressure is removed, for example, if the pressure in the air brake pressure lines drops, the release mechanism is returned automatically to the initial position where an operator can turn the wheel or crank the lever to apply the hand brake. In one embodiment, a check valve can be engaged to drop the pressure in the system.
Referring to the drawing figures, the automatic hand brake system of the present invention is indicated generally by reference number 10. Hand brake system 10 includes a housing 12 having a front wall 14 and a back wall 16. Back wall 16 is constructed so as to be mounted on the railcar, preferably at one end or the other. A railcar may employ one or two hand brake systems. In any event, it will be appreciated that most of the operative elements of the hand brake system are contained within housing 12 to protect the system from dirt, debris and weather. Hand brake system 10 includes a brake hand wheel 29 positioned on the outside of front wall 14 of housing 12. Hand wheel 29 is attached to one end of a shaft 30. Shaft 30 is appropriately journaled in bearings so as to be rotatably mounted within the housing.
There is an automatic brake release mechanism inside the housing comprising a ratchet and pawl mechanism 40, pivot mechanism 42 and an actuator which, in the illustrated embodiment, is a cylinder 44. One end of cylinder 44 is secured in the housing by bracket 46. There is a cylinder shaft 48 that can move axially within the cylinder. Shaft 48 has a bracket 50 it is exposed end. Cylinder 44 includes an automatic cylinder return 51, the function of which will be described in greater detail below. In any event, automatic cylinder return 51 can be spring loaded, fluid actuated or any acceptable design. Pivot mechanism 42 includes an arm 52 having a first end 54 pivotally attached to bracket 50. The opposite end of arm 52 is pivotally attached to a shaft 56 that extend through front wall 14 of the housing. There is a detent 57 on arm 52 adjacent the attachment to shaft 56.
Ratchet mechanism 40 has gear 58 with peripheral, unidirectional teeth 60. Gear 58 is attached to shaft 30 so as to rotate with the shaft when hand wheel 29 is turned. A clutch assembly 62 is associated with gear 58 and includes a detent seat 64 to engage and seat detent 56 when the ratchet mechanism is engaged. Clutch assembly includes pinion 66 that operatively engages a chain spool gear 68 for rotating chain drum 70. For example, when ratchet mechanism 40 is engaged, gear 58 drives pinion 66, which engages chain spool gear 68 to turn in one direction so as to apply the hand brakes through a chain 72. As known to the art, chain 72 is operatively associated with breaks on the railcar wheels. Detent 57 also keeps spool gear 68 from unwinding chain when the pivot arm is in a first position and the brakes are set. This relationship is shown in solid lines in
Although as illustrated cylinder 44 actuates release by the extension of cylinder shaft 48, it will be understood that withdrawal of the shaft could cause actuation of the system. Similarly, orientation of the actuator itself, in this case cylinder 44, whether it is disposed horizontally or vertical, is incidental to the invention.
Cylinder 44 is operatively attached to a source of pressurized fluid, for example a main reservoir 73, through an air brake line 74, as seen in
In one embodiment, cylinder 44 only requires about 20.8 cubic inches of volume when actuated. Hence, the automatic hand brake only adds minimal time to pressurize railcar air system, for example, because the automatic hand brake uses minimal volume of air from the railcar brake system. The volume can be reduced by keeping the airlines connected from the railcar to the hand brake to a minimal diameter size and minimal length.
The hand brake can also be operated manually. As seen in
The automatic hand brake system may include an air filter to prevent contamination of the cylinder. It also includes a manual valve 76, which will be described below, that can isolate the automatic brake release mechanism from the source of pressurized fluid so that it can be operated manually.
In one aspect of the invention, the mechanism employs apparatus to permit the an operator, such as the engineer located at a remote location from the train cars, for example in the locomotive, to provide a permissive to allow release all of the hand brakes at one time. One embodiment comprises a plurality of pneumatic valves and associate components in line with the automatic release hand brake that measure the change of air pressure over a period of time. One aspect of a permissive system is illustrated in
It will be noted that in one illustrative embodiment of the invention the source of pressurized fluid is air. However, it will be recognized that any type of fluid may be used to actuate the mechanism, including air, hydraulic oil, combinations of air and oil or any other fluid.
The foregoing description and the accompanying drawings are intended to be illustrative and should not be construed in a limiting sense.
This application claims the benefit of U.S. provisional application Ser. No. 61/410,457, filed Nov. 5, 2010, which is incorporated herein by reference.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US11/59261 | 11/4/2011 | WO | 00 | 3/12/2014 |
| Number | Date | Country | |
|---|---|---|---|
| 61410457 | Nov 2010 | US |
