Coupling devices have been used extensively for many years in the railroad industry to connect adjacent ends of a pair of railway cars together to form a train consist of several cars. On those railway cars which will be used in interchange service, however, such coupling devices must receive approval from the Association of American Railroads (AAR) before they can be installed on the cars. It has come to be quite well known, in this railway application, that such coupling devices perform a number of important functions. Obviously, an important function of the standard coupling device is that it facilitates the connection and disconnection of individual cars to and from, respectively, a train consist. Another important function of a standard coupler is that it enables such railway cars to negotiate the various curved portions of the track structure which are encountered during operation. Further, these coupling devices will enable a number of cars to be readily combined so that a train consist can be made up, or such cars can be easily separated individually for either loading or unloading cargo thereto or therefrom, respectively, as required. This will allow a railroad to leave a particular car at a customer's plant while delivering or picking up other cars at other locations.
In more recent times, the railroad industry has come to recognize, however, that a number of rather significant advantages can be achieved by the interconnection of several railway cars together to form a generally semi-permanent unit. This is particularly the case, for example, where such individual railway cars are adapted for use in what is commonly known in the railroad industry as "piggyback" service. A primary reason for this is that the cargo to be either loaded or unloaded is brought to or removed from, respectively, a central location which is owned and operated by the railroad normally. Generally, this cargo is either over-the-road trailers or very large containers to be shipped by sea. The individual cars which have been connected together in such substantially semi-permanent fashion are commonly known in the railroad industry as a "10-pack". These 10-pack units do not require the use of standard couplers except at each outer end of each 10-pack unit. The primary reason why such standard coupling devices are not required is that in view of their dedicated service these 10-pack units will only be broken periodically. For example, this will normally only occur when maintenance must be carried out on an individual coupler component or on some other component positioned on such railway cars that will necessitate such car be taken out of service at least temporarily. It has become obvious to the railroad industry that with the use of this coupling arrangement it is possible for them to achieve a significant reduction in their costs. Such cost-savings can be attributed to a number of reasons. For example, these reasons include lower equipment weight which results in enhanced energy savings and fewer railway trucks which results in both lower equipment cost as well as a significant reduction in maintenance requirements. However, now with the rather extensive use of these semi-permanent coupling arrangements, particularly with new cars being built for piggyback service, and with the ever increasing loads that are now being carried by modern railway cars and trains, it has been determined that it is of the utmost importance for a close-buttoned relationship to be maintained between the draft components of the coupler devices. Such close-buttoned relationship is necessary, for example, so that the effects of the impact forces, which are usually encountered under normal buff conditions during train operation, can be reduced to an acceptable level. In this manner, unnecessary damage to both cargo and rolling equipment can be held to a minimum.
Taught in U.S. Pat. No. 4,258,628, is one prior art type of articulated coupling apparatus which can be used for the above-identified purpose of connecting adjacent ends of a pair of railway cars together in such semi-permanent manner. This particular articulated coupling arrangement, as taught and illustrated therein, includes a male connection member secured to one end of a first railway car body and a female connection member which is secured to an adjacent end of a second railway car body. However, as can be seen the ends of both the male connection member and the female connection member which are secured to such car bodies do not provide any flexibility in how they are attached to such car body. The female connection member is rotatably-engaged in a center plate bowl portion of the bolster of a railway car truck in this prior art arrangement. This rotatable engagement is carried out in a manner that is well known in the railway art. The outer end portion of the male connection member is disposed for movement within a cavity formed in the outer end portion of such female connection member. To connect both the male connection member and the female connection member together in such semi-permanent manner, a pin member is utilized. This pin member is positioned in a vertical direction and is disposed in axially aligned apertures which are formed in each of the male connection member and the female connection member.
As taught in this reference, the aperture which is formed in such male connection member for receiving the pin member therein must be somewhat larger than the pin member itself. This larger aperture is required so that, while in operation, certain required movements of the coupling arrangement can be achieved. Additionally, a rear surface portion of such aperture that is located in such male connection member and which receives the pin member therein has a horizontally disposed concave configuration and a vertically disposed convex configuration. This particular configuration is required because it enables both the male connection member and the female connection member to move in each of a horizontal direction and a vertical direction in relationship to one another. Furthermore, this configuration provides, at the same time, a relatively substantial area of surface contact between the rear surface area of such pin aperture and the pin member itself.
The outer end surface of the outer end portion of such male connection member is provided with a convex configuration. This convex configuration abuttingly engages a complimentary concave surface which is formed on a front face portion of a follower member. In this coupling arrangement, such follower member is carried within the rear portion of such cavity disposed in the outer end portion of such female connection member. A pair of vertically disposed, slot-like cavities are provided on such follower members adjacent the rear surface thereof.
A first portion of a resilient member is disposed within each of such vertical slot-like cavities. A second portion of each such resilient member extends outwardly from such rear face portion of the follower member. In this manner, a portion of the exposed outer surface of each such resilient member can be engaged by a vertically disposed wedge-like element. This wedge-like element must be provided in this prior art coupling arrangement to urge both the follower member and the male connection member forward.
When this occurs the rear surface portion of the aperture formed in the outer end of the male connection member will be maintained substantially in contact with the pin member at all times.
This contact between such pin member and the rear surface portion of such aperture in the male connection member is absolutely necessary in this coupling arrangement because most of the articulated connecting members are manufactured as cast components. Consequently, in order for the manufacturer to achieve any significant reduction in the cost of this coupling device, such cast articulated connecting members receive very little, if any, finish-type machining which could provide the necessary and desirable dimensional control. In other words, these cast connecting members will generally be assembled into such coupling device as cast. Therefore, as a result of this cost-saving practice, it is quite often very difficult to provide an articulated coupling device which will be self-adjusting under the various wear conditions that will be encountered by such coupling device during in-track operation. Nevertheless, it is of the utmost importance to minimize the slack encountered in the various coupling connections during such in-track service for the reasons discussed above.
Other prior art-type articulated coupling arrangements are taught in U.S. Pat. No. 3,716,146 and Canadian Patent number 1,231,078. However, the shortcomings which are overcome by the invention to be taught hereinafter are also found in these prior art references.