Railway rolling stock – Car framing and structure – Draft-sill framing
Reexamination Certificate
1999-03-31
2001-10-23
Stormer, Russell D. (Department: 3617)
Railway rolling stock
Car framing and structure
Draft-sill framing
C105S199400, C105S415000, C105S421000, C105S228000, C213S050500, C213S051000, C213S057000
Reexamination Certificate
active
06305298
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to cast draft sill structures and railroad car center sill structures.
BACKGROUND OF THE INVENTION
Draft sills have been used to receive and house coupler systems for coupling one railroad car to another. Buff and draft forces are generally transferred between the draft sill structure, the car truck and the center sill of the car. More particularly, the draft sill structure typically receives a coupler and a yoke or other coupler mounting structure such as a draw bar and a cushioning or shock-absorbing assembly.
Continued attempts have been made to decrease the weight of railroad cars to allow for reduced energy consumption and more efficient rail transport. It has been desirable to produce railroad freight car components that are relatively lightweight and that can accommodate new car designs. In some instances, attempts have been made to reduce the weight of the draft sills themselves. Attempts have been made to produce lighter weight fabricated draft sills instead of using cast draft sill structures.
Typical fabricated sills have front and rear stops, ribs and center plate that are welded into place between side walls in the draft sill. The fabricated structure has been welded to a shear plate on the underside of the railroad car. Fabricated draft sills have typically had the advantage of being lighter in weight than cast draft sills, but have also had the disadvantage of having a generally shorter fatigue life compared to cast draft sills, due in part to increased stresses at the numerous welds in the fabricated sills.
The Association of American Railroads (AAR) has set requirements for the strength of draft sill structures. For example, the rear stops must be capable of withstanding a 1000 Klbs static buff load without failure, and future AAR requirements will require that the front stops be capable of withstanding a 900 Klbs static draft force. Given these strength requirements, it has been problematic to provide a lightweight cast draft sill that meets AAR strength requirements.
SUMMARY OF THE INVENTION
The present invention provides a lightweight cast draft sill for use in railroad cars having a shear plate. The lightweight cast draft sill of the present invention can be used in place of a standard fabricated draft sill while meeting the car builder's weight and strength requirements.
In one aspect, the present invention provides a draft sill to receive a shank of a device for connecting one railroad car to another. The draft sill comprises a front end and a back end and a pair of spaced side walls. Each side wall has a top and a bottom. The side walls have facing inner surfaces and extend substantially from the front end to the back end of the draft sill. At least parts of the tops of the side walls lie in a top plane. The draft sill has a central longitudinal plane between the side walls. The draft sill also has a center plate and an open member positioned along the central longitudinal plane of the draft sill. The open member has a generally vertical central longitudinal axis intersecting the center plate. The central longitudinal axis of the open member extends upward between the side walls between the front and back ends of the draft sill. The draft sill has a plurality of generally vertical ribs, a pair of front stops and a pair of rear stops. There is one front stop on the inner surface of each side wall. At least parts of the front stops are aligned along a front stop plane that intersects the draft sill central longitudinal plane. There is one rear stop on the inner surface of each side wall. At least parts of the rear stops are aligned along a rear stop plane that intersects the draft sill central longitudinal plane. The front and rear stops are spaced apart. The front stop plane is between the rear stop plane and the front end of the draft sill. The rear stop plane is between the back end of the draft sill and the front stop plane. The rear stop plane is between the vertical ribs and the front stop plane and is between the open member and the front stop plane. The draft sill has a front rib set that extends from each front stop to the inner surface of the adjacent side wall and toward the front end of the draft sill. The draft sill also has a rear rib set that extends from each rear stop to the inner surface of the adjacent side wall and toward the back end of the draft sill. A flange extends outward from the bottom of each side wall. Each flange has a top surface and a bottom surface. The draft sill has an interior between the inner surfaces of the side walls and an exterior beyond the side walls and beyond the top plane. At least one open area connects the interior of the draft sill and the exterior of the draft sill. The open area is above the level of the top surfaces of the flanges and includes at least one open area between the tops of the side walls and between the front stop plane and rear stop plane of the draft sill. The draft sill further includes at least one metal span connecting the side walls. The total open area connecting the interior and exterior of the draft sill above the level of the top surfaces of the flanges and between the front stop plane and a position inward of the back end of the draft sill is at least 130 square inches. At least the front stops, rear stops, front and rear rib sets, side walls and metal span comprise a unitary cast structure. The total weight of the draft sill including the side walls, connecting metal span, front and rear stops, front and rear rib sets, center plate, open member and vertical ribs is not substantially greater than the weight of a comparable fabricated draft sill of substantially the same size and having side walls, front and rear stops, front and rear rib sets, a center plate, an open member and vertical ribs.
In another aspect, the present invention provides a draft sill to receive a shank of a device for connecting one railroad car to another. The draft sill comprises a front end, a back end and a pair of spaced side walls. Each side wall has a top and a bottom. At least parts of the tops of the side walls lie in a top plane. The two side walls have facing inner surfaces and also have exterior surfaces. The side walls extend substantially from the front end to the back end of the draft sill. The draft sill has a central longitudinal plane between the side walls and a center plate. An open member is positioned along the central longitudinal plane of the draft sill and has a generally vertical central longitudinal axis intersecting the center plate. There are a plurality of generally vertical ribs. The draft sill has a pair of front stops and a pair of rear stops. One front stop and one rear stop is on the inner surface of each side wall. At least parts of the front stops are aligned along a front stop plane. At least parts of the rear stops are aligned along a rear stop plane. The front and rear stops are spaced apart. The front stop plane is between the rear stop plane and the front end of the draft sill. The rear stop plane is between the back end of the draft sill and the front stop plane. The rear stop plane is between the vertical ribs and the front stop plane. The rear stop plane is between the open member and the front stop plane. A front rib set extends from each front stop to the adjacent side wall and toward the front end of the draft sill. A rear rib set extends from each rear stop to the adjacent side wall and toward the back end of the draft sill. A flange extends outward from the bottom of each side wall. Each flange has a top surface and a bottom surface. The draft sill has an interior between the inner surfaces of the side walls and an exterior beyond the exterior surfaces of the side walls and beyond the top plane. At least one open area connects the interior and the exterior of the draft sill. The draft sill includes at least one metal span connecting the side walls. The total open area connecting the interior and exterior of the draft sill above the level of the top surfaces of the flanges and between the front stop pl
Butler, Jr. Ronald G.
Compton Douglas L.
Kaufhold Horst T.
Ladendorf Jeffery R.
Toussaint Brian A.
Amsted Industries Incorporated
Brosius Edward J.
Jules Frantz F.
Stormer Russell D.
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