This invention relates to a stop device for rail cars and in particular for use with tracks in classification yards.
A problem encountered in classification yards is the tendency of cars to “creep” and thereby compromise the efficiency of the processes of the yard, and can even constitute a danger by leaving the track, fouling switches and other tracks in the process, if not effectively stopped.
An early device is described in GB424517 (1935 to John Mitchell) for preventing cars from running backwards down an incline. A catch is pivoted in a sunken casing and is maintained in a projecting position to stop cars travelling in one direction but allowing cars or other vehicles from travelling in the opposite direction by virtue of the catch being displaceable by cars in the opposite direction. This arrangement is somewhat crude and will have limited, if any, use in classification yards, mainly because contact of a car wheel or axle with the catch may result in a violent impact.
Another prior art device is described in GB859757 (1961 to Hobbs et al) includes a similar catch or arm acting against a ram for stopping and checking individual rail vehicles such as mine cars.
It is an object of the present invention to provide a stop device which is not only useful for stopping rail cars generally but has also particular utility in situations such as classification yards.
According to the invention a device for stopping rail cars includes an articulated member adapted to move between a first raised position in which it receives a car wheel in contacting or abutting relationship causing effective stopping of the car, and a second retracted position which offers no resistance to movement of car wheels, movement between the two positions being effected by means of a hydraulic or pneumatic ram.
In a preferred form of the invention the articulated member includes a bifurcated linkage assembly, the free ends of which are movable by means of the ram—the ends being in sliding relationship and may be mounted on a shaft or the like for this purpose. The shafts can also be substituted with rollers running on the base in guide rails, or can be made to slide on a base similar to a machine saddle sliding on a machine base. The slides will induce some additional friction to aid the stopping.
The linkage assembly may be associated with hydraulic cylinders or the like energy-absorbing means that resist and stop the movement of the car when the linkage assembly is in its raised position for the car wheel/s to contact.
A pair of linkage assemblies may be provided, one corresponding to each rail, and the term “device” is intended to refer to a pair of devices.
The linkage assemblies or arms may be mounted on slides which are slidable on shafts
The device is adapted to stop a first car and to resist most of the energy resulting from the remainder of the cars that are added for coupling to the line. This is effected by the hydraulic cylinders which provide a constant resisting force as the device slows down the rail car to zero. Once the train has been constituted the linkage assembly is lowered to permit the train to be pulled from the classification track.
It is important that the device is adapted to allow coupling between a locomotive and the first car. During the coupling operation tension builds up between the device and the line of cars pushing against each other and this tension needs to be overcome by the locomotive—if the tension is not balanced when the device is in its retracted position, the first car will be pushed forwards and can constitute a danger.
It might be required to arrest the car on the device through contacting the coupler on the car and not the wheels, in which case linkage mechanisms may have to be provided that are adapted to reach about 34.5″ above the rail to contact the rail car on the car coupler.
In this configuration the coupler is on the point of contact and the locomotive may not be able to couple so that additional means of raising and retracting will have to be implemented. In this case the car will have to be arrested in place while the linkage assembly is lowered and, when coupled to the locomotive the arrestor devices can be released in order for the locomotive to take up the tension. In this event an additional arrestor system may be added to keep the rail car in position during the lowering of the device to resist the tension and keep the car from “jumping” forward. The arrestor system may be biased to the front and/or rear of the wheel to maintain the car in place.
The bifurcated linkage assembly may include anti-friction rollers to prevent the car wheels trying to “climb” on to the device.
The hydraulic cylinders may be provided with internal springs that tend to return the slides to their original position once the tension is released.
The resistive force can be changed by changing the hydraulic cylinders with respect to cylinder diameter and/or stroke length.
It may be necessary to include retarders downstream of the devices in order to reduce the incoming speed of the first (and any succeeding) car/s prior to contact with the device. Such retarders may be adapted to reduce speed to zero if required. Speed reducing devices include piston type hydraulic retarders as well as clasp or inert type retarders.
It will be appreciated that the device acts as a positive stop with the added ability of reducing speed by applying a constant resistive force, over a predetermined distance that will reduce the impact and protect the cargo in the car.
An embodiment of the invention is described below with reference to the accompanying drawings, in which:
The device of the invention includes an assembly of a pair of bifurcated articulated arms constituting a linkage assembly 10 attached to slides 12 slidable on shafts 14, the slides being activated by rams 15.
A pair of hydraulic cylinders 16 provide a resistive force as described and explained above.
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The device is contained in a casing 22 under the rails.
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Number | Date | Country | |
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61346714 | May 2010 | US |