Patent Application
20120267333
1. Field of the Invention
The invention is directed to a key retainer system for a railway cushion car which prevents a coupler key from sliding out of a key slot in a yoke and which keeps the coupler key inside the sill. The key retainer system according to the invention comprises a key retainer mounted on a cutout on the outside of a railway car sill. The key retainer system further comprises improvements to a standard E-type cushioned yoke which permit the coupler key to extend completely through the key slots in the yoke. Mounting the key retainer on the exterior of the sill ensures improved visibility of the key retainer from outside the railway car, and allows the key retainer to be repaired and/or inspected without disassembling the coupler from the yoke or the yoke from the railway car. The exterior mounting also permits the coupler key to be inserted completely through an E-type yoke, ensuring that the key cannot be rotated out of position.
Two adjacent railway cars are joined by a coupler, which extends into a yoke mounted in a generally rectangular housing on a lower portion of the railway car known as the “sill.” The coupler is secured to the yoke by a coupler key (also called a “draft key”) which extends through aligned key slots in the coupler and the yoke.
The key is prevented from shifting or falling out of the yoke with a key retainer. The prior art systems are characterized by a stop member mounted on the inside of the yoke. In a typical prior art arrangement, the yoke is retained in the key slots with the aid of corresponding notches formed in the yoke and in the coupler key. The coupler key is inserted in a first key slot in the yoke until a notch in the key abuts a mating notch in the opposite wall of the yoke. A stop member located on the inside of the yoke swivels into position against a similar notch on a side of the coupler key opposite the first side. This is sometimes called a “blind key retainer,” because the stop member is mounted inside the yoke and is not visible, or at least not readily visible, from outside the railway car. An example of this arrangement is seen in U.S. Pat. No. 3,589,527.
The prior art arrangement has several drawbacks. From a safety standpoint, the state of the key retainer cannot be easily inspected. Even as digital vision inspection technology improves, the blind key retainer system does not lend itself to robotic digital vision comparisons. Further, because the stop member is mounted on the inside of the yoke, it cannot be easily accessed for repair, requiring removal of at least the coupler to repair the retainer system.
These and other objects of the invention are realized with a key retainer and key retainer system according to the invention. The key retainer comprises: a retainer guide having an open end, a closed end, and two opposed sides extending from the closed end defining a slot. Two opposed flanges extend from either side of the slot, and each flange has a through hole, positioned so that the through holes can be vertically aligned. A key stop is inserted in the open end of the retainer guide and is slidable within the retainer guide to a position abutting the closed end of the retainer guide. The key stop also has a flange with a through hole, which is vertically aligned with the through holes on the flanges on the retainer guide when the key stop is abutting the closed end of the retainer guide. A locking member, such as a pin or bolt, is received in the aligned through holes to secure the key stop in the retainer guide. With this configuration, the retainer guide is adapted to be mounted on the outside of a railway car sill having a cutout at one end exposing at least a portion of a key slot on a yoke, so that at least a portion of the retainer guide is aligned with at least a portion of the cutout on the sill.
Mounting a key retainer system on the outside of the sill, as described above, provides for the status and integrity of the key retainer to be verified by visual inspection. An automated vision system that performs inspection while a train is in service or moving may readily be adapted to include a check of the integrity of the key retainer. Also, all maintenance, inspection, and repair can be performed while the yoke, cushion unit and coupler are installed.
A key retainer system according to the invention includes the above-described key retainer, a sill attached to the lower portion of the railway car (which may be identical to a sill found in the prior art) provided with a cutout in one of the lateral sides permitting access to a coupler key, and a yoke having uniform key slots sized to allow a draft key to be inserted all the way through the yoke, so that the draft key extends from one inner wall of the sill to the other inner wall. The system is especially adapted for a yoke which is mounted in the sill with sliding clearance and which has a recess to receive a cushion unit, including a surface for the cushion unit to bear on. This arrangement is called a “floating E-type” yoke to distinguish certain earlier yoke configurations in which the yoke and the cushion unit were integrated as a single unit. Because the coupler key does not abut the sides of the key slots on the yoke, as in the prior art, the coupler key may extend completely through the two opposed key slots in the yoke, which makes it impossible for the key to rotate out of position and cause the yoke to detach from the coupler, even while in the ‘buff’ position, a rare but catastrophic event known to occur in the prior art. Further, the member which holds the key retainer in place according to the invention is not subject to load when lateral loads are applied to the yoke, which may happen in normal operation. These and other advantages of the invention will be described in the detailed description which follows.
Referring to
The key retainer 110 is mounted in alignment with the cutout 30 in the sill 20. Key retainer 110 comprises retainer guide 90 having an open end corresponding to the open end of sill cutout 30. Two opposed sides 92, 94 extend from closed end 96 of the retainer guide, forming a slot in which key stop 140 is slidable. At least a portion of the retainer guide 90 is aligned with the cutout in the sill such that a side of the retainer guide 90 is close to the edge of the sill cutout, but preferably does not narrow the opening of the sill cutout. Most preferably, the opposed sides 92, 94 and the closed end 96 of the retainer guide line up with corresponding edges of the sill cutout. Mounting of the key retainer system may be done by welding the key retainer directly to the sill, or by mechanical means, such as by bolting. In addition to making the key retainer more visible, the sill is more adaptable to different means of attachment than the yoke itself, which is conventionally where a key retainer system is mounted. In the most preferred embodiments, the key retainer is mounted on the flat wall of the sill, and is not mounted on a flange. In
Key stop 140 physically retains the draft key and is preferably mounted so that an interior surface is about flush with an interior surface of the sill wall. Although the key retainer may protrude an insignificant amount into the interior of the sill (no more than a few millimeters), it is preferably flush. As seen in the detail of
To retain the key stop 140 in the retainer guide 90, two flanges 93, 95 extend from the sides of the retainer guide and are provided with aligned through holes. A further flange 142 on the key stop is provided with a through hole aligned with the through holes on the retainer guide flanges 93, 95. A locking member 176 is received in the aligned through holes and may be secured in any fashion known in the art. For example, the locking member may be tack welded, or it may be a threaded bolt provided with a nut. Alternatively the locking member may be provided with threads which mate with threads provided in the retainer guide. In the embodiment shown, locking member 176 is provided with a hole for receiving cotter pin 178 to secure the pin and keep the key stop in place. It is preferred, but not critical, that flanges 93, 95 extend from opposed sides of the retainer guide adjacent to closed end of the retainer guide. An advantage of the described arrangement, is that even in the case where the draft key is subjected to a lateral load, as may sometimes happen in operation, the locking member 176 is not subjected to load.
As can be seen from
The plan cutaway view of
Recess 82 is provided in the yoke 70 to receive a cushion unit (not shown) so that the cushion unit and yoke are separable, which also provides for easier construction and repair of the coupler, yoke and cushion unit assembly.
The foregoing description of the preferred embodiments is not to be deemed as limiting the claimed invention, which is defined in the appended claims.
