Abstract:
A model train car uses an improved coupling mechanism that permits close coupling of adjacent cars in a model train, while also providing a rotational operating range that permits operation of the train with tighter model track curves. The coupling mechanism operates to extend a coupling bar from the model car when the train turns to the right or left, providing clearance for further rotation of the bar. The mechanism further provides for elastic portions of the model car housing, which give way to the rotating coupling bar as the bar rotates towards its outer limits.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims priority pursuant to 35 U.S.C. § 119(e) to U.S. Provisional Application No. 60/575,594, filed May 28, 2004, which application is specifically incorporated herein, in its entirety, by reference. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Field of the Invention  
         [0003]     The present invention relates to model vehicles, such as model trains, and more particularly, to a coupling mechanism for a model train or other model vehicle.  
         [0004]     2. Description of Related Art  
         [0005]     Various model trains and vehicles are known in the art, which model an actual or imaginary train or vehicle at a reduced scale. Many model trains include a model locomotive driven by an engine. The locomotive is constructed to run on a model railway track. Various types of model tracks may be provided for different kinds of trains. For many trains, a hobbyist may obtain short segments or sections of pre-assembled model track. Track sections may include, for example, straight sections, curve sections having various radii, switches, and junctions. The track sections may be assembled and combined in various ways to construct a model track layout. Various model cars without engines are also available, which may be connected in various ways with one or more model locomotives to form trains.  
         [0006]     Model train cars may be coupled together to form a model train using various coupling mechanisms. For instance, drawbar connectors, c-shaped connectors (knuckle couplers), and ball and hitch connectors may be used to connect adjacent train cars together. Some such couplings are generally reliable and easy to couple and decouple. Some obtain higher levels of realism than others. Notwithstanding their advantages, however, couplings for model train cars may be subject to certain disadvantages. In conventional coupling arrangements, the movement of the coupling member in both directions may be limited by the outer structure of the train car. For example, when a train encounters a curve in a model track, the coupling member associated with that train car moves in the direction of the curve. If the radius of the curve is too small, the coupling member may come into contact with the structure of its connected train car. In other words, the range of travel of the coupling member is physically limited by the rigid structure of the train car. A greater range of rotation may be achieved by increasing the length of the coupling drawbar, but this may cause the train cars to be coupled too far away from one another, lending to unrealistic appearance to the train as a whole.  
         [0007]     The turning radius of the train may therefore be limited by the coupling member. Model train hobbyists may therefore be limited in their selection of track, and may not be able to construct layouts having curves that have a desired tightness in radius. Large-radius curves, in turn, may disadvantageously require a larger number of track sections to construct, and may cause a track layout to occupy more space than desired. In addition, the constraints imposed by prior-art coupling mechanisms may increase the chance of derailment of the train car, particularly when the train is moving at a relatively high speed.  
         [0008]     Accordingly, a need exists for a model train with an improved coupling mechanism that overcomes these and other limitations of the prior art.  
       SUMMARY OF THE INVENTION  
       [0009]     The invention provides a reduced-scale model train car with an improved coupling mechanism. A train assembled using cars according to the invention should be able to negotiate tracks having tighter-radius curves than was possible using prior-art coupling mechanisms, without sacrificing a close-coupled appearance.  
         [0010]     A model train car in accordance with the present invention comprises a housing shaped to resemble an actual or fanciful train car. The model train further includes a coupling mechanism attached to the model train car. The coupling mechanism comprises a drawbar or other elongated structure connected to a lower frame of the model rail car, having a coupling disposed at a distal end thereof. The coupling is configured to mate with a complementary coupling of an adjacent model car.  
         [0011]     The drawbar may be moveably connected to the model rail car. In an embodiment of the invention, the drawbar is connected to the train car using a special sliding and rotating connection structure that permits the drawbar to both rotate and move linearly relative to the rail car. When the model train is traversing a straight section of track, the special connector is configured to retract the drawbar in towards the center of the model car, drawing adjacent cars closer together. When the train is traversing a curve, the connector is configured to both rotate and extend away from the model car. The extending action advantageously provides additional clearance between the coupling at the frame or body of the model car. This additional clearance may permit a greater degree of rotation of the drawbar, and hence, permit the train to negotiate a tighter curve. As the train exits the curve, the drawbar rotates back towards the center of the car and retracts.  
         [0012]     In embodiments of the invention, the extending action of the drawbar may not provide the desired degree of rotation between cars. The extending action of the rotating and sliding connector may tend to be limited by design constraints such as available space and range of reliable motion for a cost-effective design. The coupling end of the drawbar may therefore still tend to interfere with the body of the train car near the corners of the car. To lessen such interference and permit greater rotation of the drawbar, segments of the body at the four corners of the car may be configured to be movable via an elastic connection with the body or frame. For example, segments at the corners of the body may be attached to the body via an elastic hinged or sliding connection. When the train negotiates a tight curve, rotational forces on the drawbar push the nearest corner segment outward, permitting greater rotation of the coupling mechanism and hence, adjacent train cars, than would otherwise be possible. As the train straightens out, the drawbar stops pushing on the moveable corner segment, which therefore returns to its rest position under the impetus of a return spring or other elastic member.  
         [0013]     It should be apparent that the moveable corner segment of the invention may be implemented entirely separately from the remainder of the coupling mechanism. For example, a standard vehicle frame and coupling mechanism may be fitted to a train car body having moveable corner segments, thereby providing a train car having a coupling mechanism permitting greater rotation than with a prior-art car body. In the alternative, the moveable-corner feature may be implemented partly or wholly in association with the vehicle frame.  
         [0014]     A more complete understanding of the model vehicle with coupling mechanism will be afforded to those skilled in the art, as well as a realization of additional advantages and objects thereof, by a consideration of the following detailed description of the preferred embodiment. Reference will be made to the appended sheets of drawings which will first be described briefly. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0015]      FIG. 1  is a plan view of a model railroad layout in accordance with the present invention.  
         [0016]      FIG. 2  is a simplified perspective view of a model train car in accordance with the present invention.  
         [0017]      FIG. 3  is a partial cross section view along lines  3 - 3  of  FIG. 2  of a coupling mechanism shown in accordance with the present invention.  
         [0018]     FIGS.  4 A-B are schematic plan views of a coupling arrangement of a model train in accordance with the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0019]     The present invention provides a model vehicle with an improved coupling mechanism, that overcomes the limitations of the prior art. In the detailed description that follows, like element numerals are used to indicate like elements appearing in one or more of the figures.  
         [0020]      FIG. 1  shows a first exemplary embodiment of a model vehicle system  10 . Model vehicle system  10  includes a track  12 , a power supply  14 , a train  16  and a control box  18 . In an exemplary embodiment, track  12  may comprise a three rail track that is configured for travel thereon by train  16 . Power source  14  provides power to track  12  by way of connectors  18  and  20 , whereby the power terminal of the power supply is connected to the center or third rail of track  12 , and the neutral terminal is connected to at least one of the two outer rails of track  12 . Train  16  may be configured with contacts on the bottom thereof, or an arrangement of electrically conductive metallic wheels, to pick up the applied power and supply it to the electric motor of the train. Train  16  may comprise a plurality of train cars connected by coupling members according to the invention, as described in more detail below. The arrangement described above is for exemplary purposes only and is not meant to be limiting in nature.  
         [0021]     With reference to  FIGS. 2 and 3 , in an embodiment of the invention, train car  16  includes a housing or body  22 , a coupling member  24 , first corner section  26 , and a second corner section  28 . A lower portion of car  16  may comprise a lower frame  23 . A longitudinal axis  30  may be defined extending from a first end  32  of housing  22  to a second end  34  of housing  22 . First and second corner sections  24 ,  26  may be disposed in or on a perimeter of housing  22 . A static coupling may be used at the rear  34  of each car  16  in a train, to pull moveable couplings in trailing cars. In the alternative, a moveable rear coupling using a mechanism like the described coupling mechanism, or a simplified mechanism, may likewise be disposed at a rear  34  of car  16 . A model train according to the invention may comprise any desired number of interconnected cars like train  16 , and may be pulled by one or more model locomotives.  
         [0022]     With reference to  FIG. 3 , details of an exemplary coupling mechanism  25  for car  16  are shown. Mechanism  25  may be connected to a lower frame  23  of car  16  under housing  22 . Mechanism  25  may comprise a connecting member  24  configured to be affixed to train  16  and to couple with a complementary connecting member, e.g., a rear coupling, for a second train car. It should be apparent that in  FIG. 3 , two connector members  24  are shown, representing alternative positions of the member during operation. In reality, mechanism  25  should comprise a single connector member  24 .  
         [0023]     In an exemplary embodiment, coupling member  24  comprises a drawbar connector pivotally coupled to car  16 . Coupling member  24  may comprise an elongated slot  36  in its distal portion, within which a fixed pin  38  protruding from an underside of frame  23  may be disposed. Pin  38  may be configured to retain member  24 , while still permitting it to extend and retract relative to frame  23  and car  16 . At the same time coupling member  24  is free to pivot about fixed pin  38 .  
         [0024]     Coupling mechanism  25  may further comprise a second guide member  40  protruding from member  24  and passing through a V-shaped slot  42  in frame  23 . Guide member  40  may comprise a pin, roller, or other suitable guide. Guide member  40  may be disposed within slot  42  so as to be guided as coupling member  24  moves from side-to-side of frame  23 , i.e., in a first radial direction  44  relative to longitudinal axis  30 , and a second radial direction  46  opposite first radial direction  44 . Slot  42  may comprise a V-shaped slot, or other suitable shape such as C-shaped or U-shaped. Slot  42  should be configured such that when car  16  and an adjacent connected car are being pulled and traversing a straight section of track, coupling member  24  is substantially aligned with a central longitudinal axis  30  of car  16 , and guide member  40  is located substantially at the vertex or minima  48  of slot  52  furthest from the end  32  of frame  23 . At the same time, fixed pin  38  is disposed at or near a first end  50  of elongated slot  36 . Accordingly, coupling member  24  is retracted in an axial direction under frame  23  and towards the center of car  16 , resulting in a close coupling relative to the adjacent train car.  
         [0025]     In comparison, when car  16  and adjacent cars are pulled along a curved portion of track, for example a track curved towards the right, coupling member  24  is urged in a radial direction  46  (i.e., to the right). As train  16  turns, coupling member  24  pivots about and slides along fixed pin  38 , such that pin  38  is disposed at or near a right distal end  52  of elongated slot  36 . Coupling member  24  therefore extends out from frame  23  in an axial direction. Likewise, when traversing a leftward curve, coupling member  24  moves in a left radial direction  44  and guide member  40  rides outwardly within V-shaped slot  42  towards a left distal end  54  of V-shaped slot  42  near the perimeter of housing  22 . Thus, coupling member  24  extends outward from frame  23  and rotates when car  16  and an adjacent car are traversing a curved section of track. As should be apparent from  FIG. 3 , the outward extension of the coupling permits a greater degree of coupling rotation than would otherwise be possible. Hence, a train using a coupling mechanism according to the invention may rotate to a greater degree with respect to an adjacent car, permitting the cars to traverse a tighter curve.  
         [0026]     Optionally, any number of additional or alternative guide mechanisms may be provided, for example, second guide slot  43  in frame  23 , cooperating with a guide stud  41  in member  24 . The second guide mechanism may assist in smoother operation of the primary guide provided by slot  42  and guide member  40 .  
         [0027]     Notwithstanding the advantages of the coupling mechanism as described thus far, in some cases the degree of possible rotation may still not be as great as desired. Lower corners of a train car body  22  often extend below the level of lower frame  23 , and thus may prevent coupling  24  from rotating to its mechanical limit. The invention therefore provides a method and apparatus for overcoming this limitation, as described below.  
         [0028]     With reference to  FIGS. 3-4B , moveable corner segments  26 ,  28  may be provided in housing  22  at its lower corners. These corner pieces may be formed separately from body  22 , and moveably connected to the remainder of the car body  22  so as to appear flush or integral with it. Frame  23  may be relieved or removed adjacent to the corner piece, as shown in  FIG. 3 . A spring or other elastic member may be used to keep each corner piece in its rest position. When rotation of coupling member  24  causes it to contact either of corner pieces  26 ,  28 , the corner piece moves outward from the car body  22 , permitting continued rotation of the coupling member. The coupling mechanism may thereby be afforded freedom to move through its entire side-to-side range as described above.  
         [0029]     The invention is not limited to a particular mechanism by which the corner pieces are made moveable. For example, a hinge  58  as shown adjacent to piece  26  in  FIG. 3  may be suitable, and may be coupled with a suitable spring (not shown), as known in the art. Generally, the corner pieces may be mounted using an elastic coupling of any suitable type, for example a a pivoting, sliding or stretching coupling, to give way to the coupling member when it is rotated against them. The illustrated embodiments exemplify two different structures for mounting the corner pieces  26 ,  28 , which for economy of illustration are shown together on a single frame. Corner piece  26  is shown pivoting outward, while the depicted motion of piece  28  is consistent with a coupling that slides outward or pivots upward and outward. It should be appreciated, however that it may be advantageous to use the same mounting structure for corner pieces in a particular train car  16 . Corner pieces may be of any desired size or length, and may even extend for substantially the entire length of car  16  to form a lower skirt. Generally, however, it is believed advantageous to keep corner pieces  26 ,  28  as small as possible while still remaining functional.  
         [0030]     A first exemplary corner piece  28  is shown in  FIGS. 3 and 4 A. Corner piece  28  may be mounted to housing  22  so as to be displaced laterally from the longitudinal axis  30  of car  16  in the plane of coupling member  30 . For example, piece  28  may be hinged to body  22  at a location above the plane of coupling member  24 . In the alternative, corner piece  28  may be mounted on a sliding mechanism to frame  23  or body  22 . As coupling member  24  is pulled rightward  46  by a leading car traversing a rightward curve, it contacts corner piece  28  and pushes it outward while continuing its rightward rotation. After completing the curve, the leading car pulls the coupling member back towards the centerline  30  of car  16 . A spring or other elastic member may be used to return the corner piece to its rest position. In the alternative, or in addition, corner piece  28  may be designed so that it is returned to its rest position by gravity.  
         [0031]     A second exemplary corner piece  26  is shown in  FIGS. 3 and 4 B. Corner piece  26  exemplifies a laterally hinged structure for holding the corner piece to body  22 . When pulled leftward by a leading car, coupling member contacts corner piece  26  and pivots it outward, in the direction  44  of rotation of the coupling member. After the coupling member returns to a center position, a spring or other elastic member may be used to urge the pivoting corner piece  26  back to its rest position.  
         [0032]     The present invention thereby provides a close coupling for model trains, without sacrificing the ability of the model train to negotiate curve sections having a relatively tight radius.  
         [0033]     Having thus described a preferred embodiment of a model vehicle with an improved coupling mechanism, it should be apparent to those skilled in the art that certain advantages of the within system have been achieved. It should also be appreciated that various modifications, adaptations, and alternative embodiments thereof may be made within the scope and spirit of the present invention. For example, a particular coupling mechanism has been illustrated, but it should be apparent that the inventive concepts described above would be equally applicable to other coupling mechanisms arranged according to the spirit and scope of the invention. The invention is defined by the following claims.