Rail car coupler drafted pin slot

Abstract

A rail car coupler having a body and a head coupled to the body for connecting to the coupler of another rail car. The head includes a first pin slot having a first pin protector region and a second pin slot having a second pin protector region that is spaced apart from the first pin slot to provide a space for pivotally mounting a knuckle between the first and second pin slots using a pivot pin that extends through the first and second pin slots. The first pin slot comprises at least a first portion having a non-cylindrical throughbore. The second pin slot comprises at least a second portion having a second non-cylindrical throughbore. Any forces transmitted by the pivot pin, such as during draft loading, will be borne by the main portion of the pin slot instead of the pin protector portion of the pin slot.

Description

TITLERAIL CAR COUPLER DRAFTED PIN SLOTBACKGROUND1. FIELD

[0001] The present disclosure relates to rail car couplers and, more specifically, to a pin slot profile with a draft for improved loading.2. DESCRIPTION OF THE RELATED ART

[0002] Railcar couplers are used to join one end of a railcar to an adjacent railcar using and include a pivotal knuckle that fits into the coupler and rotates about a pin between an open position that can engage the knuckle of an adjacent railcar and a closed position that can be locked in place to join the couplers of the two railcars. For example, the Association of American Railroads (AAR) standard coupler uses a knuckle that is pivotally mounted in the coupler by a pivot pin to engage and disengage from another coupler.

[0003] The current design for coupler bodies includes a straight cylindrical face in the pin slot. When loaded, the largest portion of the pivot pin contact is concentrated at the thin portion of the pin protector, creating a triangular shaped contact patch. As the load along the edge of the thin portion of the pin protector increases, the fatigue life of the coupled body is dramatically reduced. As a result, coupler bodies with high loading at the thin portion of the pin protector portion can crack, thereby leading to premature failure of the coupler body.

[0004] Pin protector failure becomes evident when the coupler body is inspected in a car shop. If the pin protector has failed, the coupler body needs to be replaced, increasing repair costs and downtime. In some cases, pin protector failure results in a portion of the pin protector being completely separated from the coupler body. In this situation, the coupler assembly may not be able to maintain function under standard operating loads, which can cause undesired separation of cars during operation. Accordingly, there is a need in the art for a coupler design that can avoid fatigue at the pin protector and thus maintain the life of the coupler to avoid failure during use.BRIEF SUMMARY

[0005] The present invention includes a coupler design that provides relief at the thin portion of the pin protector and moves the largest part of the pivot pin contact into the pin slot where the material of the coupler is thicker. More specifically, in one exemplary embodiment, the present invention may be a head for a coupler of a rail car that has a first pin slot having a first pin protector coupled to the head and including a first throughbore extending through the first pin slot and the first pin protector and a second pin slot having asecond pin protector coupled to the head and including a second throughbore extending through the second pin slot and the second pin protector. The second pin slot is spaced apart from the first pin slot to define a gap therebetween and to align the first throughbore with the second throughbore along a central axis. The first throughbore has a first portion that is non- cylindrical and the second throughbore has a second portion that is non-cylindrical. The first portion may be defined by a first surface of the first pin slot that extends at a first predetermined angle relative to the central axis. The second portion may be defined by a second surface of the second pin slot that extends at a second predetermined angle relative to a central axis. The first portion that is non-cylindrical may extend through the first pin slot and the first pin protector and the second portion that is non-cylindrical may extend through the second pin slot and the second pin protector. The first predetermined angle and the second predetermined angle may each be between one-half and one degree. The first predetermined angle and the second predetermined angle may each be three-quarters of a degree. The first portion may be positioned on a first forward facing side of the first pin slot and the second portion may be positioned a second forward facing side of the first pin slot. The first portion may be aligned about a centerline of the coupler and the second portion may be aligned about the centerline of the coupler. The first portion that is non-cylindrical may be defined only within the first pin protector of the first pin slot and the second portion that is non-cylindrical may be defined only within the second pin protector of the second pin slot. The first predetermined angle and the second predetermined angle may each be between one and three degrees. The first predetermined angle and the second predetermined angle may each be two degrees.

[0006] In another embodiment, the present invention may be a method for improving a rail car coupler. One step involves forming a head for coupling to a body of the rail car coupler, wherein the head includes a first pin slot having a first pin protector coupled to the head and a second pin slot having a second pin protector coupled to the head, wherein the second pin slot is spaced apart from the first pin slot to define a gap therebetween and to align the first throughbore with the second throughbore along a central axis. Another step involves forming a first throughbore that extends through the first pin slot and the first pin protector and has a first portion that is non-cylindrical. A further step involves forming a second throughbore that extends through the second pin slot and the second pin protector and has a second portion that is non-cylindrical. The first portion may be defined by a first surface of the first pin slot that extends at a first predetermined angle relative to the central axis and the second portion is defined by a second surface of the second pin slot that extends at a secondpredetermined angle relative to the central axis. The first predetermined angle and the second predetermined angle may each be between one-half and one degree. The first predetermined angle and the second predetermined angle may each be three-quarters of a degree.

[0007] The present invention thus causes the largest part of the pivot pin to contact the main portion of the pin slot, which is away from the thinner pin protector portion of the pin slot. During draft loading of the coupler, the loading condition forces which can otherwise crack and cause the failure of the pin protector are relocated to the strongest portions of the pin slot. The coupler design thus reduces stresses at a common failure location by moving the physical contact point away from the thinner portions of the coupler and allowing contact with the pin to occur in the deeper portion in the pin slot that is away from the failure location.BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

[0008] The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which:

[0009] FIG. 1 is a perspective view of a coupler for a rail car according to the present invention.

[0010] FIG. 2 is a cross-sectional view of a lower pin slot and pin protector of a coupler according to the present invention.

[0011] FIG. 3 is a cross-sectional view of a coupler showing an upper pin slot and pin protector according to the present invention.

[0012] FIG. 4 is a cross-sectional view of a coupler showing an upper pin slot and pin protector and a lower pin slot and pin protector according to the present invention.

[0013] FIG. 5 is a view of an upper pin slot and pin protector according to the present invention.

[0014] FIG. 6 is a cross-sectional view of a coupler showing an upper pin slot and pin protector and a lower pin slot and pin protector according to another embodiment of the present invention.DETAILED DESCRIPTION

[0015] Referring to the figures, wherein like numerals refer to like parts throughout, there is seen in FIG. 1, a coupler 10 for a railcar according to the present invention. Coupler 10 includes body 12 that extends longitudinally to a head 14 having an aligning wing 16 spaced apart from a knuckle pivot 18. Knuckle pivot 18 includes an upper pin slot 20 including an upper pin protector 22 extending integrally therefrom. Knuckle pivot 18 also includes a lower pin slot 24 including a lower pin protector 26 extending integrally therefrom.

[0016] As seen in FIG. 1, upper pin slot 20 is spaced apart from lower pin slot 24 to for a gap 28 therebetween that can accept a knuckle, with upper pin protector 22 extending downwardly toward gap 28 and lower pin protector 26 extending upwardly toward gap 28. Upper pin slot 20 has a first throughbore 30 extending therethrough including upper pin protector 22, and a lower pin slot 24 has a second throughbore 32 extending therethrough including lower pin protector 26 so that a pin may be passed through a knuckle positioned in gap 28 to pivotally couple the knuckle to head 14.

[0017] Referring to FIG. 2, second throughbore 32 of lower pin slot 24 includes a non- cylindrical portion 34 forming lower pin protector 26 and a cylindrical portion 36 forming lower pin slot 24. Non-cylindrical portion 34 is formed by an edge surface 38 that extends from the opening 40 of second throughbore 32 to a transition point 42 where the thickness of material surrounding throughbore increases from Ti to T2 at the junction of non-cylindrical portion 34 and cylindrical portion 36. Cylindrical portion 36 is formed from an edge surface 44 that extends from transition point 42 cylindrically through the remainder of lower pin slot 24. As seen in FIG. 2, edge surface 38 extends at an offset, i.e., angle (a°), along line X relative to edge surface 44 (line Y-Y) of second throughbore 32. Angle (a°) may be between one and three degrees and, preferably, two degrees relative to the longitudinal axis Y-Y of lower pin slot 24. As is known in the art, non-cylindrical portion 34 and cylindrical portion 36 may be formed by including a draft in the appropriate location of the mold where lower pin slot 24 forms when casting coupler 10 using conventional casting methods.

[0018] Referring to FIG. 3, first throughbore 30 of upper pin slot 20 includes a non- cylindrical portion 54 forming upper pin protector 22 and a cylindrical portion 56 forming upper pin slot 20. Non-cylindrical portion 54 is formed by an edge surface 48 that extends from the opening 50 of first throughbore 30 to a transition point 52 where the thickness of material surrounding throughbore increases from T3 to T4 at the junction of non-cylindrical portion 54 and cylindrical portion 56. Cylindrical portion 56 is formed from an edge surface 58 that extends from transition point 52 cylindrically through the remainder of upper pin slot 20. As seen in FIG. 3, edge surface 48 extends at an offset, i.e., angle (a°), along line X-X relative to edge surface 58 and line Y-Y of first throughbore 30. Angle (a°) may be between one and three degrees and, preferably, two degrees from the longitudinal axis Y-Y of upper pin slot 20. As is known in the art, non-cylindrical portion 54 and cylindrical portion 56 may be formed by including a draft in the appropriate location of the mold where upper pin slot 20 forms when casting coupler 10 using conventional casting methods.

[0019] As seen in FIG. 4, upper pin slot 20 and upper pin protector 22 are thus formed in the same manner of lower pin slot 24 and lower pin protector 26 as described above with respect to FIG. 2, with edge surface 48 mirroring edge surface 38 of lower pin slot 24 and lower pin protector 26 relative to the centerline C-C of coupler 10.

[0020] Referring to FIG. 5, edge surface 38 (and thus also edge surface 48) may extend circumferentially around the entire inside of upper pin slot 20 and lower pin slot 24, respectively, or can be formed on one side only as shown by the dotted lines. If edge surface 38 and edge surface 48 do not extend fully around upper pin slot 20 and lower pin slot 24, edge surface 38 and edge surface 48 are preferably positioned on the forward or outward facing side of coupler 10 relative to the direction of the head of coupler 10 as indicated, and also symmetric about the horizontal centerline C-C.

[0021] Referring to FIG. 6, upper pin slot 20 and upper pin protector 22 and lower pin slot 24 and lower pin protector 26 may be formed so that the draft is distributed over the entire first throughbore 30 and second throughbore 32, respectively, so that all portions first throughbore 30 and second throughbore 32 are non-cylindrical. In this embodiment, the entire edge surface 60 of upper pin slot 20 and the entire edge surface 62 of lower pin slot 24 are both offset from axis Y-Y by a predetermined angle (b°). Angle (b°) can be between one-half degree and one degree, and is preferably 0.75 degrees. Edge surface 60 and edge surface 62 may be positioned as explained with respect to FIG. 5.

[0022] As is understood in the art, coupler 10 is formed via sand casting and other comparable processes, such as by using a cope mold portion and a drag mold portion along with appropriately shaped cores to form the structures discussed herein from cast steel.

Claims

CLAIMSWhat is claimed is:

1. A coupler for a rail car, comprising: a body; and a head coupled to the body; a first pin slot having a first pin protector coupled to the head and including a first throughbore extending through the first pin slot and the first pin protector; and a second pin slot having a second pin protector coupled to the head and including a second throughbore extending through the second pin slot and the second pin protector, wherein the second pin slot is spaced apart from the first pin slot to define a gap therebetween and to align the first throughbore with the second throughbore along a central axis; and wherein the first throughbore has a first portion that is non-cylindrical and the second throughbore has a second portion that is non-cylindrical.

2. The coupler of claim 1, wherein the first portion is defined by a first surface of the first pin slot that extends at a first predetermined angle relative to the central axis.

3. The coupler of claim 2, wherein the second portion is defined by a second surface of the second pin slot that extends at a second predetermined angle relative to a central axis.

4. The coupler of claim 3, wherein the first portion extends entirely through the first pin slot and the first pin protector and the second portion extends entirely through the second pin slot and the second pin protector.

5. The coupler of claim 4, wherein the first predetermined angle and the second predetermined angle are each between one -half degree and one degree.

6. The coupler of claim 5, wherein the first predetermined angle and the second predetermined angle are each three-quarter degrees.

7. The coupler of claim 6, wherein the first portion is positioned on a first forward facing side of the first pin slot and the second portion is positioned a second forward facing side of the first pin slot.

8. The coupler of claim 7, wherein the first portion is aligned about a centerline of the coupler and the second portion is aligned about the centerline of the coupler.

9. The coupler of claim 3, wherein the first portion that is non-cylindrical is defined only within the first pin protector of the first pin slot and the second portion that is non-cylindrical is defined only within the second pin protector of the second pin slot.

10. The coupler of claim 9, wherein the first predetermined angle and the second predetermined angle are each between one and three degrees.

11. The coupler of claim 10, wherein the first predetermined angle and the second predetermined angle are each two degrees.

12. A method for improving a rail car coupler, comprising the steps of: forming a head for coupling to a body of the rail car coupler, wherein the head includes a first pin slot having a first pin protector coupled to the head and a second pin slot having a second pin protector coupled to the head, wherein the second pin slot is spaced apart from the first pin slot to define a gap therebetween and to align a first throughbore of the first pin slot with a second throughbore of the second pin slot along a central axis; and forming a first throughbore that extends through the first pin slot and the first pin protector and has a first portion that is non-cylindrical; and forming a second throughbore that extends through the second pin slot and the second pin protector and has a second portion that is non-cylindrical.

13. The method of claim 12, wherein the first portion is defined by a first surface of the first pin slot that extends at a first predetermined angle relative to the central axis and the second portion is defined by a second surface of the second pin slot that extends at a second predetermined angle relative to the central axis.

14. The method of claim 13, wherein the first predetermined angle and the second predetermined angle are each between one -half and one degree.

15. The coupler of claim 14, wherein the first predetermined angle and the second predetermined angle are each three-quarters of a degree.