BACKGROUND
1. Technical Field
The present embodiments relate generally to the field of railroad couplers, and more specifically, to the manufacturing of a railway coupler knuckle.
2. Related Art
Railcar couplers are disposed at each end of a railway car to enable joining one end of such railway car to an adjacently disposed end of another railway car. The engageable portion of each of these couplers is known in the railway art as a knuckle.
Typically a knuckle is manufactured with three cores, commonly referred to as a finger core in the front portion of the knuckle, pivot pin core in the center of the knuckle, and a kidney core at the rear of a knuckle. The finger core and kidney core reduce the weight of the knuckle. Still, knuckles can weigh about 80 pounds, and must be carried from the locomotive at least part of the length of the train during replacement. This distance can be anywhere from 25 up to 100 or more railroad cars in length.
Coupler knuckles are generally manufactured from cast steel using a mold and the three cores. During the casting process itself, the interrelationship of the mold and three cores disposed within the mold are critical to producing a satisfactory railway freight car coupler knuckle. Many knuckles fail from internal and/or external inconsistencies in the metal through the knuckle. If one or more cores move during the casting process, then some knuckle walls may end up thinner than others resulting in offset loading and increased failure risk during use of the knuckle.
Furthermore, multiple thin ribs have been located within a front face section associated with a finger cavity at the front of the knuckle. These multiple, thin ribs are known to be a source of premature failure of the couple knuckles so designed.
BRIEF DESCRIPTION OF THE DRAWINGS
The system may be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like-referenced numerals designate corresponding parts throughout the different views.
FIG. 1 is a top view of the knuckle cores with the finger core isolated from the pivot pin and kidney core.
FIG. 2 is a bottom view of the knuckle cores of FIG. 1.
FIGS. 3 and 4 are perspective views of the two cores used to form the knuckles of
FIGS. 5 and 6, in spatial relationship before the molds are poured. FIG. 5 is a top view of a knuckle after molding with use of the knuckle cores of FIGS. 1-4.
FIG. 6 is a bottom view of the knuckle after molding with use of the knuckle cores of FIGS. 1-4.
FIG. 7 is a top view of the knuckle, indicating cross section views along lines A-A and B-B through the finger cavity of the knuckle of FIGS. 5-6, and showing dimensions of the finger core support holes.
FIG. 8 is a side view of FIG. 7, indicating a cross section view alone line E-E.
FIG. 9 is the section view along line E-E of the knuckle of FIG. 8, showing dimensions of a continuous, solid, uninterrupted, thick rib located along a horizontal centerline of the knuckle that passes through the pivot pin section hub.
FIG. 10 is the cross section view along line A-A of FIG. 7, indicating the thickness of the continuous, solid, uninterrupted thick rib located along a horizontal centerline of the knuckle that passes through the pivot pin section hub.
FIG. 11 is a front, cross section view along line B-B of the knuckle of FIG. 7.
FIG. 12 is a top view of two opposing knuckles, indicating resultant forces on pulling lugs of the knuckles, and indicating a cross section view along line D-D through the length of one of the knuckles.
FIG. 13 is the cross section view along line D-D of FIG. 12, indicating the resultant forces from a side of the knuckle.
FIG. 14 is a schematic illustration of a coupler knuckle manufacturing assembly, in accordance with at least one embodiment of the knuckle of FIGS. 5-6.
FIG. 15 is a flowchart illustrating a method for manufacturing the railcar coupler knuckle of FIGS. 5-6.
DETAILED DESCRIPTION
In some cases, well known structures, materials, or operations are not shown or described in detail. Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. It will also be readily understood that the components of the embodiments as generally described and illustrated in the Figures herein could be arranged and designed in a wide variety of different configurations.
Referring to FIGS. 1-4, the present embodiments of a railroad coupler knuckle combines a pivot pin core 10 and a kidney core 12 into a first core. A second core is an isolated finger core 14, seen best in FIG. 3 with a unique shape having a large core footprint. The enlarged core footprint improves stabilization of the finger core 14 within the cope and drag mold portions (FIG. 14) during the molding process. Accordingly, the improved stabilization helps to prevent movement during the molding process, thereby helping to insure the intended wall thicknesses, which improves the strength and fatigue life of the coupler knuckle.
FIGS. 5 and 6 are, respectively, top and bottom views of a coupler knuckle 16 after molding with use of the knuckle cores 10, 12, 14 of FIGS. 1-4. The coupler knuckle 16 includes a tail section 20, a hub section 22 and a front face section 24. The hub section 22 includes a pivot pin hole 30 formed therein for receiving a pivot pin to pivotally couple the knuckle 16 to a coupler for coupling to a railcar. The pivot pin hole 30 is formed from at least a portion of the first core (10, 12). The pivot pin hole 30 is generally cylindrical. The knuckle 16 also includes a finger cavity 40 in the front face section created with the isolated finger core 14 during molding. The coupler knuckle 16 also includes a top pulling lug 46 and bottom pulling lug 46a used to pull the knuckle 16 when attached to the train.
The front face section 24 includes a nose section 52, which includes a generally cylindrical flag hole 54 opening formed in an end region of the nose section 52. A pulling face portion 58 is disposed inwardly from nose section 52, at least a portion of which bears against a similar surface of a coupler knuckle of an adjacent railcar to couple the railcars together as shown in FIG. 12.
FIG. 7 is a top view of the knuckle 16, indicating cross section views along lines A-A and B-B through the finger cavity 40 of the knuckle of FIGS. 5-6, and showing dimensions of the finger core support holes. In one embodiment, the depth D and length L of the cross section of the finger cavity 40 are approximately 1.6″ and 4.3″, respectively, as shown in FIG. 7. Alternative dimensions are envisioned, as would be apparent to one skilled in the art of railroad couplers. FIG. 8 is a side view of FIG. 7, indicating a cross section view alone line E-E.
As shown in FIGS. 9-11, the finger core 14 is designed to create within the finger cavity 40 a single, continuous, solid, uninterrupted thick rib 60 located along a horizontal centerline 64 of the knuckle 16 that passes through the pivot pin hub section 22. A pair of side fins (or walls) 66 are attached to the thick rib 60 and extend along the front face section 24. The single, thick rib 60 replaces the multiple thin ribs of prior art knuckles, thus aiding in prevention of premature knuckle failure due to break down of the multiple thin ribs. The single, thick rib 60 may extend from the flag hole 54 to the other side of the knuckle 16, as best seen in FIG. 11, wherein the single, thick rib 60 may connect with the pivot pin hub 22. As shown in FIGS. 9-11, the single, thick rib 60 may have a length LRIB of about 3.6″, a depth of about 1.9″, and a thickness TRIB of about 1.5″ in one embodiment. Alternative dimensions are envisioned, as would be apparent to one skilled in the art of railroad couplers.
As shown in FIGS. 12-13, when two opposing coupler assemblies, including the knuckle 16 described above, are pulled in opposite directions by the pulling lugs 46 and 46a, arrows 100 indicate the resultant forces on the knuckle 16. The cope and drag molds as designed and displayed in the embodiments herein, create draft angles from the centerline 64 of the knuckle. Hence, when two knuckles are coupled together, the train line force is concentrated to the centerline of the knuckles. FIG. 13 illustrates how the centerline load is efficiently transferred through the single, thick rib 60 to the pulling lugs 46 and 46a of the coupler knuckle 16.
FIG. 14 is a schematic illustration of a coupler knuckle manufacturing assembly 200, in accordance with at least one embodiment of the knuckle of FIGS. 1-6. The knuckle manufacturing assembly 200 includes a cope mold section 210, an upper section 220 of a coupler knuckle, the combined pivot pin and kidney core 10, 12 and the isolated finger core 14 used in the manufacturing process, a lower section 240 of the coupler knuckle, and a drag mold section 250.
The cope mold section 210 and the drag mold section 250 include mold cavities 212 and 252, respectively, into which a molten alloy is poured to cast the coupler knuckle. Mold cavities 212 and 252 are configured to correspond to the desired external surfaces of the coupler knuckle to be manufactured using cope and drag mold sections 210 and 250. The combined (first internal) pivot pin and kidney core 10, 12 is positioned with the cope or drag mold such as to be isolated from, and without contact with, the finger core 14, or second internal core. The result is that, after the molding process, molten alloy substantially separates the finger cavity 40 from the pivot pin hub section 22.
FIG. 15 is a flowchart illustrating a method for manufacturing a railcar coupler knuckle, in accordance with a particular embodiment, understanding that the upper section 220 and the lower section 240 of the coupler knuckle are not part of the assembly to cast the knuckle but a result of that casting process. The method begins at step 300 where cope and drag mold portions are provided. The cope and drag mold portions may each include internal walls, formed of sand using a pattern or otherwise, that define at least in part, perimeter boundaries of a coupler knuckle mold cavity. The mold cavity corresponds to the desired shape and configuration of a coupler knuckle to be cast using the cope and drag mold portions.
At step 310, the combined pivot pin and kidney core (first internal core) is positioned within either the cope mold portion or the drag mold portion. The first internal core is configured to define a kidney cavity and a pivot pin hub within a coupler knuckle. For example, a single core may be used that includes a pivot pin portion and a kidney portion that form the pivot pin hub and kidney cavity, respectively, but as a single void in the knuckle 16.
At step 320, the isolated finger core (second internal core) is positioned within either the cope mold portion or the drag mold portion, the second internal core to define a finger cavity. At step 330, the cope and drag mold portions are closed with the one or two internal cores therebetween using any suitable machinery. At step 340, the mold cavity including the one or two internal cores is at least partially filled, using any suitable machinery, with a molten alloy which solidifies to form the coupler knuckle.
Some of the steps illustrated in FIG. 15 may be combined, modified or deleted where appropriate, and additional steps may also be added to the flowchart. Additionally, steps may be performed in any suitable order without departing from the spirit and scope of the embodiment described therein.
The terms and descriptions used herein are set forth by way of illustration only and are not meant as limitations. Those skilled in the art will recognize that many variations can be made to the details of the above-described embodiments without departing from the underlying principles of the disclosed embodiments. For example, the steps of the method need not be executed in a certain order, unless specified, although they may have been presented in that order in the disclosure. The scope of the invention should, therefore, be determined only by the following claims (and their equivalents) in which all terms are to be understood in their broadest reasonable sense unless otherwise indicated.
Patent Application
20120228256
