Abstract:
A modular seat frame for a school bus seat based on a minimized number of components and allowing for different orders of assembly.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Technical Field 
         [0002]    The present invention relates to school bus seats and more particularly to a modular school bus seat frame characterized by differentiated sub-assembly possibilities to ease of installation on a bus and readily modified to meet differing configuration requirements by customers all with a minimized number of differing parts. 
         [0003]    2. Description of the Problem 
         [0004]    School bus seats are built to meet many differing customer specifications. For example, some bus seats must accommodate three point safety belts by providing a compatible upper back rest, other specifications call for a universal child restraint attachment equipped lower frame, while still others provide standard DOT (United States Department of Transportation) seat backs. At the same time customers can specify seats in different widths or heights and can demand various strength requirements. 
         [0005]    Differing customers&#39; specifications have required substantially or entirely different component sets. The need to supply such component sets has even occurred in relation to completed vehicles that have been put into service, particularly when the vehicle has been moved from one state or municipality to another due to differing requirements of the new jurisdiction. 
         [0006]    Modular construction of bus seat frames is known, one example being taught in U.S. Pat. No. 6,886,889 to Vits et al. FIGS. 18-20 of the Vits &#39;889 patent teach a modular seat based on four major sub-assemblies. The sub-assemblies include a frame assembly, a floor mount assembly, a passive restraint panel and a seat member. The frame assembly in turn comprises a pair of opposed side forms which are generally elbow shaped and concave in construction, two upright members or posts which support the passive restraint panel, longitudinal front and rear members for mounting between the opposed side forms and cross members between the front and rear members. The frame assembly is supported by a pair of identical pedestals, which are collectively termed the floor mount assembly even though they are not directly connected, and which are disposed under the respective side forms. In some embodiments one of the pedestals is replaced by a wall mount bracket shown in FIGS. 26 and 27 of the patent. 
       SUMMARY OF THE INVENTION 
       [0007]    It is an object of the invention to provide a modular bus seat frame with sub-assemblies exhibiting flexible constituent elements. 
         [0008]    It is a further object of the invention to provide a modular bus seat which minimizes the number of changes in components to meet differing seat specifications. 
         [0009]    The invention provides a modular seat assembly for school busses. The seat assembly includes an aisle riser including a support neck, a wall riser including a support neck, a front cross support fitted between the aisle riser and the wall riser, a rear cross support fitted between the aisle riser and the wall riser, a perimeter tube fitted at opposite ends to the support necks of the aisle riser and the wall riser, respectively, and a back panel supported within the perimeter tube behind and above the rear cross support. 
         [0010]    Additional effects, features and advantages will be apparent in the written description that follows. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0011]    The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein: 
           [0012]      FIG. 1  is a perspective view of a school bus. 
           [0013]      FIG. 2  is a perspective view of a prior art school bus seat frame. 
           [0014]      FIG. 3  is a perspective view of a modular school bus seat frame in accordance with a preferred embodiment of the invention installed in a vehicle. 
           [0015]      FIG. 4  is an exploded view of an embodiment of the school bus seat frame illustrated in  FIG. 3 . 
           [0016]      FIG. 5  is a perspective view illustrating possible sub-assemblies for the school bus seat frame. 
           [0017]      FIG. 6  is a perspective view of a possible alternative set of partial assemblies for the school bus seat frame. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0018]    Referring now to the drawings and in particular to  FIG. 1 , a school bus  10  with which the present invention is advantageously used is illustrated. The seat frames of the present invention are installed in the interior  18  of the bus. 
         [0019]      FIG. 2  illustrates a prior art seat frame  20 . Seat frame  20  includes a closed-loop, multi-piece full perimeter tube  26 . Perimeter tube  26  is shaped in the form of a deep “L” following the perimeter of the seat bottom and seat back for the bus seat frame  20 . The perimeter tube  26  is supported by an aisle riser  22  and a wall riser  24 . An internal frame  28  and a back seat support  30  are nestled within the closed perimeter tube  26 . Internal frame  28  parallels portions of the perimeter tube  26 , reinforcing the sides of the perimeter tube and adding a seat back bottom brace  34  and a cross member  32  to give the frame  20  rigidity. Excluding the risers  22 ,  24 , virtually none of the components are reusable should seat specifications, such as width, or height of the seat back be changed. 
         [0020]    Referring to  FIG. 3 , an assembled modular school bus seat frame  40  is illustrated disposed on the floor  42  (shown in phantom). Modular frame  40  is supported on its inside end from a chair rail  62  of a school bus interior wall  44  (shown in phantom). Modular school bus seat frame  40  is supported both from the floor  42  and from the wall  44 . Support from the floor  42  is provided by an aisle riser  46 . Support from the wall  44  is provided by a wall riser  48 . Aisle riser  46  and wall riser  48  differ from the aisle risers and floor risers known from the art in that they form part of what would traditionally be considered the frame itself. Both the aisle riser  46  and the wall riser  48  are modified to function as frame elements, in part by inclusion of necks  50  which provide bases of support for an open, partial perimeter tube  52  used to define the top and sides of a seat back portion of frame  40 . The partial perimeter tube  52  is a C shaped member mounted at opposite ends in necks  50  which defines the top and sides of the seat back. Suspended on and within the partial perimeter tube  52  is a seat back panel  54 . Extending between and fitted into the aisle riser  46  and the wall riser  48  are front and back latitudinal supports  60  and  56 . Supports  56  and  60  come in varying lengths to support seats of varying widths. Risers  46  and  48  are molded elements with interior (i.e. facing) sides which are contoured to reinforce the riser. Mounting plates are used set in the risers to provide points of attachment for the front and back latitudinal supports  56 ,  60  fit. 
         [0021]      FIG. 4  illustrates the modular seat frame  40  in an exploded view. Necks  50  are formed from C-channel sections extending upwardly from the upper rearward areas of aisle riser  46  and wall riser  48 . The channels are open one with respect to the other. Open perimeter tube  52  fits into the necks  50  at its opposite ends. The joint formed by joining the ends of the perimeter tube  52  to the necks  50  is reinforced by addition of an U-reinforcement member  64  which fits into the neck  50  between the tube  52  and the interior of the necks  50 . Bolts  66  are inserted through the walls of the necks  50 , U-reinforcement members  64  and the ends of perimeter tube  52 . 
         [0022]    Back panel  54  includes a partial perimeter lip  74  by which the panel is attached to tube  52 . Risers  46 ,  48  include inner face contours  76  which position the ends of rear and front cross supports  56 ,  60 , which leave wells between an upper, inwardly turned flanges  78 . Cross supports  56 ,  60  may have different cross sectional shapes along as the ends of the members fit the risers  46 ,  48  to allow construction of a joint. The major members of the assembly/sub-assemblies may be attached to one another using self piercing rivets, adhesives or welds. Aisle riser  46  includes legs which support the structure from the floor. A plate  68  is provided for securing fasteners between the riser  46  and a vehicle floor. Wall riser  48  includes an attachment flange  72  allowing securing of the wall riser to a wall support. Plate  68  and washer  70  are provided as part of the attachment process. 
         [0023]      FIGS. 5 and 6  illustrate alternative partial fabrications of the modular seat frame, the system of  FIG. 5  providing for delivery for installation in two sections or sub-assemblies  80 ,  82 . Sub-assembly  80  includes perimeter tube  52 , its reinforcing braces and back seat support  54 . Sub-assembly  82  comprises risers  46  and  48  and the longitudinal braces  56  and  60 . 
         [0024]      FIG. 6  illustrates a division of frame into a section  80 , as described above, and the two risers  46 ,  48  and the two braces  56 ,  60 . The divisions of the frame illustrate that the frame can be constructed from its constituent parts or from sub-assemblies in virtually any order. 
         [0025]    As typically assembled the preferred embodiment of the seat frame uses MIG welds instead of self-pierce rivets, adhesives or spot welds. The total length of welds has been reduced in length from about 62 inches for the seat frame of  FIG. 2  to about 24 inches in the present preferred embodiment, and it is possible to reduce even this level if rivets are used. 
         [0026]    While the invention is shown in only one of its forms, it is not thus limited but is susceptible to various changes and modifications without departing from the spirit and scope of the invention.