BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to railcars for transporting vehicles, typically also called vehicle carrier railcars, and more particularly, directed toward draft arm structures for an aluminum vehicle carrier railcar.

2. Background Information Railcars have long been used for transporting vehicles, in particular automobiles and light trucks, long distances, generally from the point of manufacture or import location to dealerships or locations where the automobiles or trucks can be subsequently transported by truck. As with other freight, a vehicle carrying railcar is designed to carry a maximum number of motor vehicles in each railcar. This has lead to the development of a bi-level or tri-level vehicle carrier railcar. In addition to the desire to carry a maximum number of vehicles on each vehicle carrier railcar, the existing railcars have been designed to minimize damage or vandalism of the vehicles such that. many vehicle carrying railcars are designed as an enclosed structure. Conventionally, the existing vehicle carrier railcars are formed of steel that presents other problems for the railcar including additional weight and rust or corrosion in the cargo interior. Some attempts have been made to address this, such as a fiberglass panel articulated railcar disclosed in U. S. Patent No. 5,511,491.

A railcar draft arm, also called a draft sill, of some design or other is utilized in practically all railway cars and normally comprises an elongated and rather heavy, box-like steel fabrication or casting. A railcar draft arm is positioned between the center sill and the coupler of a railcar. A draft arm is located on each end of the center sills, which extends along the length of the railcar body, as part of the underframe ; thus two draft arms are used with each railcar. The draft arms, as with the center sill, are welded to the underframe of the railcar body. The draft arms serve the multi-purpose of connecting the center sill to the railcar couplers and transmitting the draft and buff (longitudinal) loads through the railcar to the next railcar. In addition, the draft arm provides the connection between the railcar body and the trucks, which support the railcar body at both ends of the railcar. At each end of the center sill, the draft arm is fitted and welded at its inboard end to the center sill. The outboard end of the draft arm has either a cast integral striker or a separate striker assembly that is fitted with and welded to the draft arm. A coupler assembly and its associated yoke are mounted to the outboard end of the draft arm, through the opening formed by the striker. The coupler assembly and yoke are secured to the draft arm.

Draft arms, or draft sills, of any design include a center plate in some form or other which, in essence, comprises a rather heavy cylindrical extension protruding slightly from the bottom rear surface of the draft arm having an aperture through the center axis (also called a kingpin hole) and a flat, circular lower bearing surface which rotateably rests in the center bowl of the railcar truck bolster. With a draft arm rigidly attached to each end of the railcar's center sill, each with a cylindrical center plate extending downward to engage and rotatably rest upon a railcar truck, the two car trucks will support the two ends of the railway car. Due to the excessive weight borne by the center plate portion of the draft arm, prior art draft arms are normally designed to include rather heavy supporting gussets to assure that the shape and integrity of the draft arm and the center plate portion extending therefrom are maintained. Accordingly, the entire weight of the railcar is supported by the two railcar trucks through the center plates of the two draft arms, and as a result, the design of the draft 'arms have tended to be rather heavy for purposes of supporting the weight.

Conventionally, draft arms are manufactured of cast steel or fabricated from numerous steel components. The draft arms therefore contribute a substantial part of the total weight of the railway car. Since there are weight limits placed on shippers of goods for preserving the safety and conditions of the track, the quantity of goods that may be placed in or on a railcar is affected by the weight of the railcar body, the trucks and other railcar components. Thus, a reduction in the weight of the railway cars, including the draft arms, will result in an increase in the total capacity of goods shipped by a rail line owner. Therefore, it is highly desirable to reduce the weight in the draft arms without a decrease in strength.

A variety of cast draft arms have been proposed essentially to reduce the weight associated with the draft arm. For example, U. S. Patent No. 4,252,068 to Nolan discloses a unitary cast draft sill structure that has a transition element including a structural splice or a fish-tail plate for mounting in a telescopic fashion with the railroad car center sill, a pocket for mounting a center filler plate, draft lugs at opposite ends of a draft gear pocket, a striker plate, a coupler carrier, and a draft key slot. U. S. Patent No. 5,704,296 to Gagliardino et al. discloses a railway car draft sill having a significantly lighter weight center plate design in full compliance with all AAR (American Association of Railroads) specifications. U. S.

Patent No. 5,931,101 to Kaufhold et al. also discloses cast draft arm structures. U. S. Patent Nos. 5,809,899; 4,549,666; 4287,834; and 3,954,066 also relate to general draft arm structures.

There is a need to provide a draft arm structure in a vehicle carrier railcar that effectively balances overall weight, manufacturing costs and assembly time. The object of the present invention is to address the problems of the above-cited prior art. It is a further object of the present invention to provide a lightweight vehicle carrier railcar constructed from non-corroding materials adjacent to the load carrying interior. A further object of the present invention is to provide an efficient, cost-effective draft arm structure for the vehicle carrier railcar.

SUMMARY OF THE INVENTION The above objects are achieved with an aluminum vehicle carrier railcar according to the present invention. The railcar according to the present invention utilizes underframe components constructed principally of steel and an upper body comprised principally of aluminum components to create a uni-body design. The steel underframe components that could potentially introduce ferrous components inside the railcar are covered with aluminum. The underframe is supported on a pair of railcar trucks with the underframe including a center sill and a pair of two piece draft arms. Each draft arm includes an outboard one-piece, hollow rectangular draft arm casting adapted to receive a coupler assembly therein and an inboard one-piece hollow rectangular draft arm casting having a center plate and coupled to the outboard draft arm casting. The inboard and outboard draft arm castings may be coupled together by welding. Additionally, the inboard and outboard draft arm castings may be overlapped in a telescoping fashion to allow for two weld line connections therebetween.

These and other advantages of the present invention will be clarified in the detailed description of the preferred embodiment together with the attached figures in which like reference numerals represent like elements throughout.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a perspective view of an aluminum vehicle carrier railcar according to the present invention; Fig. 2 is a plan view, partially in section, of a draft arm of the vehicle carrier railcar shown in Fig. 1; Fig. 3 is a sectional side elevational view the draft arm shown in Fig. 2; Fig. 4 is cross sectional view of the draft arm shown in Fig. 3; Fig. 5 is cross sectional view of the draft arm shown in Fig. 3; and Fig. 6 is an end view of the draft arm shown in Fig. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An aluminum vehicle carrier railcar 10 according to the present invention is illustrated in Fig. 1. The aluminum vehicle carrier railcar 10 of the present invention utilizes a steel underframe (not completely shown) supported on a pair of spaced trucks 12. The steel underframe is formed with a pair of two-piece cast steel draft arms 14 (also called draft sills), a roll formed center sill (not shown) extending between the trucks 12 and other steel underframe components. The cold formed center sill is described in U. S. Patent No.

6,119,345, which is incorporated herein by reference. The two piece cast steel draft arms 14 represent a significant feature of the present invention and will be described in detail in connection with Figs. 2-6 below.

An aluminum upper structure 16 is attached onto the steel underframe. The aluminum upper structure 16 includes a pair of aluminum spaced side panels. The side panels include a plurality of spaced aluminum side stakes 18 extending the length of the aluminum vehicle carrier railcar 10. Perforated aluminum side sheets 20 extend between and are attached to each adjacent pair of side stakes 18 to form the side panel structure. The side sheets 20 are attached by mechanical fasteners to the side stakes 18, or possibly by other coupling mechanisms such as welding. The side sheets 18 are perforated allowing ventilation to the cargo area of the railcar 10. Additionally, the invention anticipates utilizing the perforations to provide identifying indicia 22 on the vehicle carrier railcar 10 which may be in the form of a logo or other text or graphical information.

The side stakes 18 and the side sheets 20 extend between a side sill 24 and a top chord 26. The side stakes 18 are attached to the side sill 24 by mechanical fasteners as shown in Fig. 4. The side panel is attached to the top chord 26 through mechanical fasteners as well. Other coupling mechanisms may be also be utilized. The top chord 26 and side sills 24 extend the length of the vehicle carrier railcar 10. The ends of the side panels include access ladders 28.

The aluminum vehicle carrier railcar 10 additionally includes a roof structure or roof system formed of overlapping corrugated and rolled aluminum panels 30 extending between and attached to the top chord 26 through mechanical fasteners. The overlapped ends of adjacent panels 30 may be fastened together with mechanical fasteners through the aligned holes. The ends of the roof structure may include roof latch strikers 32 to assist in the closure of end doors 34.

Corner posts are provided at the end of the side panel structure extending between the side sill 24 and the top chord 26 to provide a mounting position for the pivotable end doors 34. The doors 34, the side panel structures and the roof structure combine to form an enclosed cargo area for the aluminum vehicle carrier railcar 10. The interior compartment of the aluminum vehicle carrier railcar 10 includes an aluminum decking 36 and other aluminum components to prevent any substantial ferrous material from being exposed to the vehicles in the cargo area. The upper surface of the cast draft arms 14 in the cargo area will be coated, such as by spraying or the like, to prevent exposure to the cargo interior. An advantage of the vehicle carrier railcar 10 of the present invention is that the interior is substantially all aluminum since the side walls, the decking, the roof and the doors are formed primarily of aluminum and, therefore, substantially non-corrosive. Other metal components within the interior can be formed of stainless steel or coated material or otherwise of a non-corrosive type material to essentially eliminate the rust problem in the cargo interior.

The details of the two piece cast draft arm 14 are shown in Figs. 2-6. As best shown in Figs. 2 and 3, the two piece cast draft arm 14 is formed of an outboard one piece hollow rectangular draft arm casting 40 welded to an inboard one piece hollow rectangular draft arm casting 50. As will be evident to those skilled in the art, the terms outboard and inboard refer to the respective position of these components relative to the railcar 10. The outboard one piece hollow rectangular draft arm casting 40 is adapted to receive a coupling assembly 52 with an associated coupling yoke 54. The outboard casting 40 includes a front support plate 60 and back support plate 62 for the securement and attachment of the coupling assembly 52 and associated coupling yoke 54. The coupling yoke 54 pivotally connects to a coupler 56 (shown in phantom) through a draft pin 58. The construction of the coupling assembly 52, coupling yoke 54, coupler 56 and draft pin 58 are believed to be apparent in view of the figures to one of ordinary skill in the art.

The inboard casting 50 includes the center plate structure 66 with a kingpin hole 68 therein. The outboard end 70 of the inboard draft arm casting 50 is adapted to telescope within the inboard end 72 of the outboard draft arm casting 40 as best shown in Fig.

3. This telescoping arrangement allows for two weld lines 76 and 78 to be utilized for connecting the inboard draft arm casting 50 to the outboard draft arm casting 40. The weld lines 76 and 78 are shown respectively in Figs. 4 and 5.

The two piece cast draft arm 14 of the present invention effectively balances the relatively lightweight casting and ease in assembly and manufacturing time to the provision of an outboard rectangular hollow box-like casting and an inboard rectangular hollow box-like casting. The two piece cast draft arm 14 together with the cold formed center sill and the aluminum upper structure combine to form an overall lightweight vehicle carrier railcar improved over the prior art structures.

It will be readily apparent to those of ordinary skill in the art that various changes may be made to the present invention without departing from the spirit and scope thereof. The described embodiment is intended to be illustrative of the present invention and not restrictive thereof. The scope of the present invention is intended to be defined by the appended claims and equivalents thereto.