Patent Application
20090184562
1. Technical Field
The present invention relates to school bus seats and more particularly to a joint system for attaching seat back frames to the remainder of the seat frame sub-structure.
2. Description of the Problem
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. Alternatively, customers can specify seats in different widths or heights and can demand various strength requirements. School bus passenger seats vary in height and width resulting in different seat back performance characteristics.
Differing customers' specifications have required substantially or entirely different component sets. The need to supply such component sets has even occurred relative to completed vehicles that have been put into service where the vehicle has been moved from one state or municipality to another, based on differing requirements of the new jurisdiction. The variability in size has contributed to varying component sets meant to meet strength standards. Multiple tubes, brackets and gussets are incorporated into welded seat assembly. Components were added to the various seat assemblies until the resulting design was compliant. Various seat widths and heights may use different hardware based on these changes. Therefore, seats have exhibited additional variation in component parts to meet the FMVSS 222 requirements.
Representative of prior art school bus seat frame systems are those of
The invention provides for a seat frame built from subassemblies that attach at joints. These joints are able to accept fasteners, thereby eliminating welding operations, and allowing the subassemblies to be stocked in a painted condition. The minimum level of subdivision of the seat frame is into two sections, a seat back and a lower frame. The lower frame includes risers with receiving necks into which the seat back can be mounted. The seat back includes a partial perimeter framing tube which ends in rectangular sections which are engaged in the necks extending from the lower frame. The lower riser has the stamped section that accepts the upper seat frame square tube. Components are easily stackable and shipable, and may be shipped in a painted condition. Assembly is accomplished with conventional fasteners, and easy to use hand tools. In addition, the system lends itself to automated assembly steps.
Additional effects, features and advantages will be apparent in the written description that follows.
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:
Referring now to the drawings and in particular to
Referring to
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 supports 56, 60. Risers 46, 48 have integral inwardly turned flanges 78 along their top and front edges. In addition, risers 46, 48 have a back edge flange 71, which are also inwardly turned. Flanges 71 and 78 provide surfaces against which opposite surfaces of the front and rear cross members 60, 56 may be placed to be secured by self pierce rivets (not shown), or other methods such as low temperature welding. Front cross member 60 is substantially formed in three panels, front panel 61, intermediate panel 63, and top panel 65 with panel 63 being intermediate to panels 61 and 65. The angle between panels 61 and 65 corresponds to the angle between the front and top edge sections of flange 78, allowing the cross member to be brought into contact with both portions of the flange concurrently. Panel 63 intersects both panels 61 and 65 obliquely along the respective interior side (i.e. the underside of the member relative to the risers) and positioned between the two panels functions as a cross brace between the flange 78 portions.
Rear cross member 56 incorporates two major sections, a top section 57 and a back section 59. The ends of top section 57 and back section are angled (essentially a right angle) to allow them flush mating of the sections to the under surface of the top portion of flange 78 and the forward surface of flange 71. Self pierce rivets (not shown), glue or welding are used to connect the member to the riser.
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 lip 72 allowing securing of the wall riser to a wall support. Plate 68 and washer 70 are provided as part of the attachment process.
Stamped seat risers 46, 48 in the lower frame sub-assembly 82 are formed to accept the perimeter tube 52 of the seat back sub-assembly 80. Features on the riser and perimeter tube are self-aligning and provide a significant surface area along which the interior of the necks 50 and the ends of tube 52 meet. This supports clamping and formation of the joint between the seat back and the lower seat frame. This joint takes advantage of the stamped seat risers by providing the formed sections (i.e. necks 50) that accept ends of the perimeter tube 52 of the seat back sub-assembly 80. The features on the riser and the perimeter tube are self-aligning, and provide sufficient clamping surface to allow the seat to meet the strength requirements that are needed for the seat to perform correctly in accident situations. It also takes advantage of having a square cross-section at the interface. This distributes clamp loads, tolerates manufacturing variability, and allows the use of standard square tubing. Joining may be completed using bolts 66, MIG welds, adhesives, etc.
Components are easily stackable and shipable, and may be shipped in a painted condition. Assembly is accomplished with conventional fasteners, and easy to use hand tools. Alternately, the same design lends itself to automated assembly.
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.
