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 where the core for the front portion of the knuckle has been eliminated.
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 core used to define a pivot pin cavity and kidney cavity.
FIGS. 2 and 3 are perspective views of the knuckle core of FIG. 1.
FIG. 4 is a schematic illustration of a coupler knuckle manufacturing assembly for manufacturing a coupler knuckle using the knuckle core of FIGS. 1-3.
FIG. 5 is a top view of a coupler knuckle molded using the coupler knuckle manufacturing assembly of FIG. 4 and knuckle core of FIGS. 1-3, indicating a cross section view along line A-A.
FIG. 6 is the cross section view along line A-A of the knuckle of FIG. 5.
FIGS. 7 and 8 are, respectively, solid and line top views of the knuckle of FIGS. 5-6 after completion of the molding process.
FIGS. 9 and 10 are, respectively, solid and line bottom views of the knuckle of FIGS. 5-6 after completion of the molding process.
FIGS. 11 and 12 are, respectively, solid and line perspective views of the knuckle of FIGS. 4-9 after completion of the molding process.
FIG. 13 is a flowchart illustrating a method for manufacturing the railcar coupler knuckle of FIGS. 5-12.
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. 1-3, the present embodiments of a railroad coupler knuckle combines a pivot pin core 10 and a kidney core 12 into a single core used in manufacturing the coupler knuckle. No finger core is required. As can be seen in FIG. 4, at least one finger cavity 40 (and/or 40′) is formed from portions of the cope and drag molds during the molding process, thus eliminating the need for another core or portion of a core that would be required to form the finger cavity. The at least one finger cavity 40 helps to reduce the weight of the coupler knuckle. The advantage of manufacturing the coupler knuckle without use of a finger core includes use of fewer cores, or if one core is used, the single core requires less sand. Reduction of the number of cores or of the overall size of a single core reduces the manufacturing cost.
More specifically, FIG. 4 is a schematic illustration of a coupler knuckle manufacturing assembly 100 for manufacturing a coupler knuckle (16 in FIGS. 5-6). The knuckle manufacturing assembly 100 includes a cope mold section 110, an upper section 120 of the coupler knuckle, the single pivot pin and kidney core 10, 12 used in the manufacturing process, a lower section 140 of the coupler knuckle, and a drag mold section 150. Of course, two separate cores could be used, a pivot pin core 10 and a kidney core 12, in lieu of the single pivot pin and kidney core 10, 12.
The cope mold section 110 and the drag mold section 150 include mold cavities 112 and 152, respectively, into which a molten alloy is poured to cast the coupler knuckle. The mold cavities 112 and 152 are configured to correspond to the desired external surfaces of the coupler knuckle to be manufactured using cope and drag mold sections 110 and 150. In the present embodiments, a cope finger section 114 of the cope mold cavity 112 and a corresponding drag finger section 154 of the drag mold cavity 152 form the at least one finger cavity 40 during the molding process. Additionally, a cylindrical flag hole (54 in FIG. 5) may be formed within the at least one finger cavity 40 by including a cylindrical pin as part of the cope and drag finger mold sections 114, 154. The cope and drag finger sections 114, 154 may be joined in the center of the mold cavities 112, 152, forming a single finger section once the cope and drag mold portions 110, 150 are closed. The single internal core 10, 12 includes pivot pin and kidney portions to form corresponding pivot pin and kidney cavities.
FIG. 5 is a top view of a coupler knuckle 16 molded using the coupler knuckle manufacturing assembly 100 of FIG. 4 and the single knuckle core 10, 12 of FIGS. 1-3. 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 single internal core 10, 12. The pivot pin hole 30 includes generally cylindrical sidewalls. The knuckle 16 also includes at least one finger cavity 40 in the front face section 24 created with the cope and drag finger sections 114, 154 during molding. The coupler knuckle 16 also includes a top pulling lug 46 and a 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. 6, the cope and drag finger sections 114, 154 of the cope and drag mold cavities 112, 152, respectively, are designed to create within the at least one 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 approximately from the flag hole 54 to the other side of the knuckle 16. In one embodiment, the depth D and length L of the cross section of the single, thick rib are approximately 1.9″ and 1.7″, respectively, as shown in FIGS. 5 and 6. The thickness T of the single, thick rib 60 as shown in FIG. 6 may be approximately 3.0″ in one embodiment. The single, thick rib 60 transfers the draft load of the train along a direct path to the pulling lugs 46.
FIGS. 7 and 8 are, respectively, solid and line top views of the knuckle 16 of FIGS. 5-6 after completion of the molding process. FIGS. 9 and 10 are, respectively, solid and line bottom views of the knuckle 16 of FIGS. 5-6 after completion of the molding process. Note that in this embodiment, the knuckle 16 includes two separate finger cavities 40, 40′ in each of the top and bottom thereof. One of these finger cavities 40′ includes the flag hole 54, through which water may drain from the knuckle 16. In the alternative from what is shown, in another embodiment, the two separate finger cavities 40, 40′ may be combined into a single, joined cavity 40.
FIGS. 11 and 12 are, respectively, solid and line perspective views of the knuckle 16 of FIGS. 5-9 after completion of the molding process using the coupler knuckle manufacturing assembly 100. Note finger cavities 40, 40′ formed from the cope and drag finger sections 114, 154 of the cope and drag mold cavities 112, 152 discussed with reference to the manufacturing assembly 100 of FIG. 4.
FIG. 13 is a flowchart illustrating a method for manufacturing the railcar coupler knuckle 16 of FIGS. 5-12, and which uses the coupler knuckle manufacturing assembly 100 of FIG. 4. The method begins at step 200 where cope and drag mold portions are provided that create a mold cavity, at least a part of which includes a finger section. 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. The finger section forms at least one finger cavity of the coupler knuckle.
At step 210, at least one internal core is positioned within either the cope mold portion or the drag mold portions, wherein the at least one internal core is configured to define a kidney cavity and a pivot pin cavity within the coupler knuckle. At step 220, the cope and drag mold portions are closed with the one or two internal cores therebetween using any suitable machinery. At step 230, the mold cavity including the at least one internal core is at least partially filled, using any suitable machinery, with a molten alloy which solidifies to form the coupler knuckle. The at least one internal core defines the kidney and pivot pin cavities, and the finger section of the mold cavity defines at least one finger cavity of the coupler knuckle.
Some of the steps illustrated in FIG. 13 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
20120217217
