1. Field of the Invention
The present invention relates to railroad couplings, and more particularly to a railroad coupler knuckle having external weight reducing features and a method of forming the same.
2. Background Information
A railroad coupling (or a coupler) is a device for connecting rolling stock, i.e. the railcars, in a train. The design of the coupler is standard, and is almost as important as the track gauge, since flexibility and convenience are maximized if all rolling stock can be easily and quickly coupled together. The equipment that connects the couplings to the rolling stock is known as the draft gear.
The Janney Coupler is a semi-automatic railway knuckle coupler. The earliest commercially successful version of the semi-automatic Knuckle Coupler was patented by Eli H. Janney in 1873 bearing U.S. Pat. No. 138,405 which is incorporated herein by reference. Mr. Janney, a major in the Confederate Army during the American Civil War and serving on Gen. Robert E. Lee's staff, was a dry goods clerk post war in Alexandria Va., home of the modern day United States Patent and Trademark Office, where he developed his knuckle coupler. The City of Alexandria named one of their streets in his honor, Janney's Lane.
In 1893, satisfied that a semi-automatic knuckle coupler could meet the demands of commercial railroad operations and, at the same time, be manipulated safely, the United States Congress passed the Safety Appliance Act (SAA). Its success in promoting switchyard safety was stunning. Between 1877 and 1887, approximately 38% of all rail worker accidents involved coupling. That percentage fell as the railroads began to replace link and pin couplers with automatic couplers. By 1902, only two years after the SAA's effective date, coupling accidents constituted only 4% of all employee accidents. Coupler-related accidents dropped from nearly 11,000 in 1892 to just over 2,000 in 1902, even though the number of railroad employees steadily increased during that decade. Thus the semi-automatic knuckle coupler has played a critical role in improving railway safety for workers.
In the United Kingdom, where the semi-automatic knuckle coupler is fitted to some rolling stock, mostly for passenger trains, it is also known as a “Buckeye Coupler”, possibly originating from the coupler's manufacture as early as 1890 by the Buckeye Steel Castings firm in Columbus, Ohio. The AAR/APTA Type E, Type F, and Type H tightlock couplers are all compatible semi-automatic Knuckle couplers, but are employed on specific types rail cars (general freight, tank cars, rotary hoppers, passenger, etc.).
Prior to the formation of the AAR (Association of American Railroads) these types of couplers were known as MCB Couplers (Master Car Builders Association). After 1910 the MCB reconstituted itself into the AAR. In 1913 the American Steel Foundries (ASF) had developed the new Type “D” coupler that was accepted as the standard coupler for the USA, and no new equipment could be built using any other coupler. This standard design ended the market for couplers with a proprietary head design, which were common in the MCB days, to all but those exported from the USA to other countries not governed by the AAR standards. The Interlocking contour of knuckle couplers was the first aspect to be standardized. In the MCB years, prior to about 1910, there were many proprietary “head” designs, and many MCB standard contours, which were constantly evolving and changing (as the approved standard contour for new couplers) every few years.
In about 1910 the producers were all using the then standardized MCB-10 contour, soon to become the AAR-10. In 1930 the AAR Type “D” was improved and became the Type “E”; the contour, however, stayed the same. A few years later the 10 contour was modified into a then optional standard called the 10A contour.
The most modern contour, for a plain Type “E” knuckle coupler, is still the AAR-10 and 10A, which are largely indistinguishable from the 1910 era MCB-10 contour. The same MCB-10 contour has been an approved standard for interchange service for over 100 years, with only the slightest dimensional changes. The Type “H” or “tight-lock” couplers, which are used on passenger-carrying rolling stock, also use slight revisions to the old 10A contour. Type H coupler, also called a “tight-lock” variation, is intended to reduce slack action and improve safety for passenger cars is now under the supervision of the APTA (American Public Transportation Association).
The conventional knuckle currently available is a cast knuckle that includes cored sections, such as disclosed in U.S. Pat. No. 4,605,133. The front core of a knuckle is commonly referred to as the finger core. The finger core is commonly constructed to produce an internal cavity having thin ribs. These ribs made out of the standard grade E cast steel have demonstrated a weakness to the load environment with the development of fatigue and/or hot tear cracks. The fatigue cracks can grow over time and eventually lead to knuckle failure which results in separation of railcars. Separately, internal or external cracks in the knuckle are a cause for replacement of the knuckle. The rear core of a knuckle is commonly referred to as the kidney core. Knuckles can sometimes break within this portion of the knuckle and this has proven to be a very undesirable location for a failure. A failure in this region of the knuckle can lead to knuckle jamming within the coupler body and prevent a change out of a failed knuckle, thereby requiring the entire coupler assembly to be replaced, a very costly repair.
U.S. Pat. No. 5,954,212 discloses a lightweight knuckle for use in an AAR Standard E or F type railroad car couplers. The outer contouring and inner voids of the knuckle are radically changed from an existing AAR Standard knuckle. The nose of the knuckle is provided with a pair of parallel, coplanar flat surfaces between which is a projection which extend outwardly from the flat surfaces and terminates at an outer curved surface which has the same curvature as the corresponding curvature of the existing AAR Standard knuckle. U.S. Pat. No. 6,129,227 discloses a similar lightweight knuckle.
U.S. Pat. No. 8,302,790 discloses a railway coupler knuckle which has a cavity formed inside the tail portion and at least a portion of the transition portion and a first wall extends between surfaces of the cavity adjacent the transition portion.
U.S. Patent Application Publication 2012-0217217 discloses a cast coupler knuckle formed with internal cavities without using a conventional finger core. See also U.S. Pat. Nos. 8,662,327, 8,646,631, 8,631,952, 8,499,819, 8,485,371.
U.S. Pat. Nos. 8,297,455 and 8,381,923 disclose a knuckle for a railway coupler system made without internal voids or cores. Instead, external circular or disc shaped pockets are formed on the front face and tail portion surface to reduce weight. The knuckle is formed by investment casting (a process based upon lost-wax casting).
U.S. Pat. No. 9,038,836 discloses a lightweight, coupler which is constructed from cast austempered ductile iron.
U.S. Pat. No. 9,199,652 discloses a lightweight, fatigue resistant knuckle utilizing improved internal coring and/or rib arrangements using an austempered metal, such as, for example, austempered ductile iron, austempered steel, as well as other austempered metals and austempered metal alloys.
The above identified patents and publications are incorporated herein by reference. There remains a need in the art for railroad coupler knuckles that reduce weight, improve manufacturability and improve fatigue life.
This invention is directed to a railroad coupler knuckle with external weight reducing features. The railroad coupler knuckler of the present invention meets AAR contour requirements and it includes unique external weight reducing features that strategically reduce weight without compromising strength or fatigue life.
The design of the railroad knuckle of the present invention allows for formation of the knuckle through forging techniques and thus allows for the use of a better grade of steel compared to AAR Grade E and such forging processes will yield much higher fatigue life compared to cast knuckles.
One aspect of the invention provides an E-type coupler knuckle comprising a front face configured to transmits the buff forces of the train; and at least two external weight saving pockets with at least one intervening support ridge on the front face of the knuckle extending into the knuckle from an exterior surface of the knuckle, and wherein each external weight saving pocket is a structure that is capable of being formed in one of a forging operation or casting operation without requiring an internal core. A method of forming the coupler is disclosed.
The elements that characterize the present invention are pointed out with particularity in the claims which are part of this disclosure. These and other aspects of the invention, its operating advantages and the specific objects obtained by its use will be more fully understood from the following detailed description in connection with the attached figures.
A conventional E-type coupler knuckle is well known to those of ordinary skill in the art, however it may be illustrative to review the structure of a conventional coupler to explain the present invention and the positioning of the weight saving external features of the present invention.
A conventional E-type coupler knuckle, as shown in
The pulling face 3 is the surface of the knuckle that transmits the draft forces through coupler. The throat 4 of the knuckle is the narrow portion on the inside of the knuckle which transitions from the pulling face 3 to the tail 8. The two buffing shoulders 5 work together with the front face 1 to transmit buff forces into the coupler body through cooperating or corresponding surfaces on the coupler body.
The pulling lugs 6 are formed by a combination of a substantially straight surface and a curved or radial surface and each lug 6 engages a corresponding surface on the coupler body to transmit draft forces through the pulling lug 6 into the coupler body. The locking face 7 is a generally flat surface configured to abut the coupler lock when the lock has dropped into the locked or coupled position. In the locked or coupled position the coupler lock is sitting on the lock shelf 16 (discussed below) and the lock in this position resists the moment created by the draft forces.
The tail 8 of the E-type coupler knuckle is a contoured surface that allows the knuckle pivot between coupled and uncoupled position. Further the top of the tail 8 provides surface for the lock to ride upon as knuckle is pivoted to a position in which the lock drops onto the lock shelf 16 to lock the coupler knuckle in position. A tail pad is opposite the tail lock and resists the moment created by the buff forces. The tail pad may be pronounced (larger) to reduce slack in the knuckle.
The tail stop 9 is the surface of the knuckle that engages with the coupler wall in the buff mode and may be considered the portion of the knuckle which transitions from the tail 8 to the spine 17 (discussed below).
The coupler knuckle includes a hub feature 10 around the pin. It is meaningful to note that if knuckle works correctly (i.e. it is not worn) then no buff or draft forces are transmitted through the pin itself. The knuckle includes a pivot pin hole 11 configured to receive a pivot pin there through, about which the coupler can rotate with the lock out of the locked position. It is known that the pivot pin hole 11 may include relief cuts or grooves to prevent binding of the pin, as known in the art. The knuckle further includes pin protector surfaces 12 that are configured such that they cooperate with coupler components to transmit forces if knuckler starts to wear. In other words the surfaces 12 are configured to protect the pin.
The coupler knuckle includes a heel 13 that may be considered as the transition from the front face 1 to the hub feature 10. Further, a thrower pad 14 is included in a bottom portion of knuckle and this pad 14 cooperates with a feature of the thrower that moves with upward lifting of the lock to push against the thrower pad to pivot the knuckle open. The thrower pivots the knuckle as the lock is lifted out of the locked position.
The coupler knuckle includes a flag hole 15 which is configured to receive a safety indicator flag, which gives a universal visual indication not to couple to the car. The flag is used on a leading car when work is being conducted in an area in which coupling of the train of cars must be avoided. As noted above the knuckle includes a lock shelf 16 which is configured to hold the lock when it has dropped into the locked or in the secured position. Finally the E-type knuckle includes a spine 17 which is considered the transition surface from the tail stop 9 to the hub feature 10.
Within the meaning of this application an external weight saving pocket is a feature extending into the knuckle 30 from an exterior surface of the knuckle 30, and is a structure that is capable of being formed in a forging operation or casting operation without requiring an internal core. The design of the railroad knuckle 30 of the present invention allows for formation of the knuckle through forging techniques and thus allows for the use of a better grade of steel compared to AAR Grade E and such forging processes will yield much higher fatigue life compared to cast knuckles.
The weight saving features 32 of
It should be understood that the weight saving features 32, 42 and 52 above may be designed to include intersecting ridges. For example one or more vertical ridges could be added to intersect with the horizontal ridges 34 of
The present invention further includes external weight reducing features 62 in the tail surface 8 of the knuckle 30 as shown in the embodiments of
The present invention further includes external weight reducing features 72 or 82 or 92 in the spine 17 of the knuckle 30 as shown in the embodiments of
The embodiment of
The embodiment of
The present invention contemplates forming the knuckle 30 to include the weight saving features on the front face 1, the tail surface 8 and the spine 17 as shown, and more significantly incorporating these weight saving features on a combination of these surfaces. For example
While the invention has been shown in several particular embodiments it should be clear that various modifications may be made to the present invention without departing from the spirit and scope thereof. The scope of the present invention is defined by the appended claims and equivalents thereto.
This application claims priority to U.S. Patent Application Ser. No. 62/297,990 filed Feb. 22, 2016, entitled “Railroad Coupler Knuckle with External Weight Reducing Features” which is incorporated herein by reference.
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4605133 | Altherr | Aug 1986 | A |
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9199652 | Brook et al. | Dec 2015 | B1 |
20090289023 | Marchese | Nov 2009 | A1 |
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Number | Date | Country | |
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20170240189 A1 | Aug 2017 | US |
Number | Date | Country | |
---|---|---|---|
62297990 | Feb 2016 | US |