Abstract:
A method for constructing a bus, wherein a module associated with the front end of the bus is separately constructed and assembled to the shell after interior components of the bus have been installed. The shell of the bus can be fabricated at a first work station. The shell can be made transversely or laterally with respect to the longitudinal access of the bus to one or more work stations. At the subsequent work stations, interior components of the bus can be moved through the open ends of the bus. After the majority of the interior components have been installed with respect to the bus, the module supporting the windshield and bumper can be installed with respect to the shell. The module can also support the dashboard and steering column.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of the provisional patent application 60/352,702 for a BUS CONSTRUCTION, filed on Jan. 28, 2002, which is hereby incorporated by reference in its entirety. This claim is made under 35 U.S.C. §119(e); 37 C.F.R. § 1.78; and 65 Fed. Reg. 50093. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to a method of manufacturing a motor vehicle bus and to the bus structure resulting from the invention methodology. 
     BACKGROUND OF THE INVENTION 
     Buses are typically manufactured by forming a closed shell structure including a roof, a structural floor, sides, front-end, and rear-end, moving the closed shell structure along a path aligned with the longitudinal axis of the structure, and loading components of the bus into the shell structure through the windows, doors, or windshield opening. The components may include, for example, the seats and the passenger compartment floor. This method is time consuming and labor intensive since it involves loading individual components into the bus individually and through relatively small apertures in the shell structure. 
     SUMMARY OF THE INVENTION 
     According to the invention, the shell structure is formed with an open front-end; the shell structure is moved laterally from station to station in a direction generally normal to the lengthwise axis of the shell structure; the interior components of the bus are loaded into the interior of the shell structure through the open front-end; a front-end module is attached to the front of the shell structure to close the front-end of the bus shell; the wheel assemblies are installed; and the shell structure is moved on its wheels along its lengthwise axis to various stations where the windows, doors, windshield, and exterior cladding are applied from locations generally outside of the shell structure. 
     Other applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
         FIG. 1  is a perspective exploded view of a bus shell structure according to the invention; 
         FIG. 2  is a perspective exploded view of an alternate shell structure; 
         FIG. 3  is a layout view of an assembly plant for forming the bus structure; 
         FIG. 4  is a perspective view illustrating the loading of the seats into the shell structure; and 
         FIG. 5  is a perspective schematic view illustrating the loading of the passenger floor into the shell structure. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     As seen in  FIG. 4 , the plant  10  for assembling the bus structure includes assembly stations  1 – 7  and pre-assembly stations  8 – 17 . 
     The basic bus shell structure  20  is formed in known manner at station  1  utilizing known assembly techniques and known jigs. Specifically, shell structure  20  includes lattice members  20   a  forming the sides of the shell, lattice members  20   b  forming the roof of the shell, and lattice members  20   c  forming the structural floor of the shell. Note that the front and rear ends  20   e  and  20   d  of the shell structure are open. The front-end of the shell structure, rather than being formed initially at station  1  as a fixed part of the shell structure, is formed as a separate module structure  22  in the pre-assembly area  15 . Following formation of the shell structure  20  at station  1 , minus the front module  22 , the shell structure is moved in a direction lateral to the lengthwise axis of the shell structure, utilizing suitable dollies, to station  2  where the passenger floor of the bus is installed in overlying relation to the structural floor  20   c.    
     As best seen in  FIG. 4 , the passenger floor or over-floor  24  may be prepared in two sections  24   a  and  24   b  at pre-assembly station  8  whereafter both sections are moved from pre-assembly station  8  through the open front-end  20   e  of the shell structure for installation in the shell structure. Floor structure  24   a  will be understood to be installed over the usual kick-up overlying the rear axle of the vehicle and floor section  24   b  will be understood to be installed forwardly of section  24   a  to cover the primary floor area of the shell structure. Floor sections  24   a ,  24   b  may be secured to the shell structure  20  using suitable glues for example. Floor sections  24   a ,  24   b  may be initially installed in the shell structure in an upperwardly tilted position, as seen in dash lines  FIG. 4 , whereafter they may be pivoted downwardly to their flat installed positions. 
     Following the floor installation at station  2  the shell structure  20  is moved laterally on the dollies to assembly station  3  where the engine assembly  26 , prepared in pre-assembly station  9 , may be installed through open rear end  20   d  of the shell structure and the seats  28 , prepared at pre-assembly station  10 , may be installed through the open front-end  20   e  of the shell structure. With reference to  FIG. 5 , the seats may be installed utilizing a forklift  30  positioned at pre-assembly station  10  and equipped with a boom  32  extending forwardly from the mast of the lift truck and including a plurality of pins  34  each hangably supporting a bus seat  28 . With this arrangement the forklift may be maneuvered to insert the boom  32  carrying the seats  28  into the interior of the shell structure  20  through the open front-end  20   e  of the shell structure to position the seats proximate their ultimate locations in the bus, whereafter it is a simple matter to remove the seats  28  from the respective pins  34  and install the seats in the bus, thereby minimizing the amount of movement required to install each seat and specifically avoiding the awkward problem of moving each seat into the interior of the bus through a narrow window or side door opening and thereafter moving the seat lengthwise in the bus to its proper location. The seats are installed in the bus employing the usual bolting techniques. 
     Following installation of the engine assembly and the seats, the shell structure is moved laterally on the dollies to assembly station  4  where further interior and engine components are installed with the engine components being prepared at pre-assembly station  11  and installed through the open rear  20   d  of the shell structure and the interior components being prepared at pre-assembly station  12  and installed through the open front-end  20   e  of the shell structure. 
     The shell structure is thereafter moved laterally on the dollies to assembly station  5  where further interior components may be installed through the open front-end  20   e  of the shell structure from pre-assembly station  13  and a heating and air conditioning unit  36  (HVAC), prepared at pre-assembly station  14 , may be installed through the rear  20   d  of the shell structure in overlying relation to engine assembly  26 . 
     The shell structure is thereafter moved laterally on the dollies to assembly station  6  where the front-end module  22 , which has been formed at pre-assembly station  15 , is suitably attached to the front-end  20   d  of the shell structure utilizing, for example, bolts whereby to close the open front-end  20   e  of the shell structure. Module  22  may include instrument panel  38 , windshield  40 , steering column assembly  42 , headlamp assemblies  44 , front bumper  46 , as well as suitable brake, throttle, and shift controls. Alternatively, as seen in  FIG. 2 , the front module may include only the windshield and front fascia and bumper of the bus with the instrument panel, steering column assembly, and vehicle controls being formed as a part of the main body shell structure  20 . Following attachment of the module  22  at station  6 , the shell structure is suitably elevated, the dollies are removed, and front and rear axle/wheel assemblies  48 ,  50 , prepared at pre-assembly station  16 , are slid under and suitably attached to the shell structure so that the shell structure is now supported for rolling movement on its wheels. 
     The bus is now rolled on its wheels in a direction parallel to the lengthwise axis of the shell structure to assembly station  7  where the bus windows  52 , doors  54 ,  56  and side cladding  58  maybe installed from the pre-assembly station  17  wherein the installation takes place primarily from labor performed outside the opposite sides of the shell structure. 
     From station  7  the bus may be moved longitudinally on its wheels to further stations (not shown) where further exterior componentry may be suitably added whereafter the bus may be moved to suitable test and inspection stations. 
     The described bus structure and manufacturing methodology has several advantages as compared to prior art structures and methodologies. To wit:
         the use of a modular front-end that is not attached to the main body shell structure until a later point in the assembly process allows all of the major interior components of the bus to be installed through the open front-end of the bus, rather than through narrow openings provided by the side doors and side windows of the shell structure where the front-end is fixedly secured to the main body shell structure prior to the installation of the interior components;   the late phase attachment of the front-end module allows an L-shaped assembly process wherein the bus is moved initially laterally through several stations in a direction normal to the lengthwise axis of the bus whereafter, following attachment of the front-end module and installation of the axle/wheel assemblies, the bus is moved in a direction parallel to the lengthwise axis of the bus. This L-shaped assembly format allows the provision of pre-assembly areas in the area defined between the legs of the L and in the areas along the outer faces of the legs whereby to provide a compact factory floor package plan with a substantial savings in floor space;   the use of the modular front-end allows the front-end to be removed in the event of a front-end accident and replaced immediately with a new replacement front-end so that the bus is out of service only for the time required to install the new front-end rather than for the much longer time required to repair the front-end;   the use of pre-assembly areas in parallel relation to the main assembly line to fabricate all of the primary sub-assemblies of the vehicle minimizes the number of workers working on the bus as it moves along the main assembly line, whereby to simplify the assembly procedures along the main assembly line;   the use of multiple pre-assembly areas allows specialists in each sub-assembly operation to be stationed at the respective sub-assembly areas, whereby to assure accurate, precise pre-assembly of the various sub-assembly components; and   the ability to install the floor through the open front-end of the shell structure in two large sections is vastly preferable to the prior art assembly procedure whereby, because of the closed front-end, the floor is moved into the interior of the bus in small sections which are thereafter pieced together and built up utilizing sanding and bondo operations to form the final composite floor structure.       

     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the description, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.