U.S. patent application number 12/016513 was filed with the patent office on 2009-07-23 for variable length reinforcement to control seat back performance.
This patent application is currently assigned to International Truck Intellectual Property Company, LLC. Invention is credited to Erik C. Wilson.
Application Number | 20090184561 12/016513 |
Document ID | / |
Family ID | 40436465 |
Filed Date | 2009-07-23 |
United States Patent
Application |
20090184561 |
Kind Code |
A1 |
Wilson; Erik C. |
July 23, 2009 |
VARIABLE LENGTH REINFORCEMENT TO CONTROL SEAT BACK PERFORMANCE
Abstract
A modified seat frame provides a seat back frame mounting
reinforcement which can be conveniently varied in length and
strength to vary the allowed degree of deflection and energy
absorption provided by the seat back upon rear impact.
Inventors: |
Wilson; Erik C.; (Decatur,
IN) |
Correspondence
Address: |
International Truck Intellectual Property Company,
4201 WINFIELD ROAD
WARRENVILLE
IL
60555
US
|
Assignee: |
International Truck Intellectual
Property Company, LLC
Warrenville
IL
|
Family ID: |
40436465 |
Appl. No.: |
12/016513 |
Filed: |
January 18, 2008 |
Current U.S.
Class: |
297/452.2 |
Current CPC
Class: |
B60N 2/42709 20130101;
B60N 2/4214 20130101; B60N 2/682 20130101 |
Class at
Publication: |
297/452.2 |
International
Class: |
A47C 7/02 20060101
A47C007/02 |
Claims
1. A modular seat frame comprising: first and second risers; a
partial perimeter tube for a seat back frame supported from the
first and second risers at joints formed between opposed ends of
the perimeter frame and open necks in the first and second risers;
and reinforcement members located in the joint overlapping portions
of the partial perimeter tube and the necks of the first and second
risers.
2. A modular seat frame as claimed in claim 1, further comprising:
the reinforcement members being open channel members fitting
outside of the partial perimeter tube and inside of the necks and
being shaped to conform to the section shapes of the partial
perimeter tube and neck sandwiched between the two.
3. A modular seat frame as claimed in claim 2, further comprising:
the reinforcement members having lengths chosen to control strength
of the joints and to control deformation of the seat back frame
upon rear impact into the seat back frame.
4. A modular seat frame as claimed in claim 2, further comprising:
the reinforcement members having holes located to control strength
of the joints and to control deformation of the seat back frame
upon rear impact into the seat back frame.
5. A modular seat frame as claimed in claim 3, further comprising:
installation on a school bus.
6. A modular seat frame as claimed in claim 4, further comprising:
installation on a school bus.
7. A modular seat frame as claimed in claim 2, further comprising:
the reinforcement members being welded to the ends of the perimeter
tubes.
8. A modular seat frame as claimed in claim 2, further comprising:
the reinforcement members being welded to the inside surfaces of
the open necks.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Technical Field
[0002] The present invention relates to school bus seats and more
particularly to a structural member used to reinforce seat joints
and thereby control the location and degree of deformation of the
seat back upon rear impact by an object.
[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.
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. FMVSS (Federal Motor Vehicle
Safety Standard) 222 requirements dictate the seat back deflection
be controlled to fall within a specified window of force versus
deflection. The specified window has minimum as well as maximum
limits for this deflection.
[0005] 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.
SUMMARY OF THE INVENTION
[0006] The invention provides for placing the variability relating
to seat back strength and the degree of allowed deflection under
force to be focused into one reinforcement component. In a modular
seat frame the seat back has its foundation in an aisle riser and a
wall riser, and includes a perimeter frame provided by a partial
perimeter tube mounted at opposed ends in necks extending from the
aisle riser and wall riser. A reinforcement member fits into the
neck/partial perimeter tube joint. The length of the reinforcement
member can be varied, and the reinforcement member itself weakened
at some point along its length to vary the strength and allowed
deflection under rear impact of the seat back. In the preferred
embodiment the length of the reinforcement member can be varied, as
well as features such as holes can be added to limit the strength,
and increase the amount of energy that is absorbed at the joint. It
also allows control of where the bending takes place. This allows
common frames to be used across height and width variation, with
their resulting differences in the amount of loads that they will
absorb.
[0007] Additional effects, features and advantages will be apparent
in the written description that follows.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] 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:
[0009] FIG. 1 is a perspective view of a school bus.
[0010] FIG. 2 is a perspective view of a prior art school bus seat
frame.
[0011] FIG. 3 is a perspective view of a modular school bus seat
frame incorporating the present invention as installed in a
vehicle.
[0012] FIG. 4 is an exploded view of the school bus seat frame
illustrated in FIG. 4.
[0013] FIG. 5 is an exploded view of a joint between a riser and a
seat back perimeter tube in which the reinforcement element of the
present invention may be placed.
[0014] FIG. 6 is a perspective view of the reinforcement element of
the invention.
[0015] FIG. 7 is an exploded view of a joint between a riser and a
seat back perimeter tube illustrating an alternative location for
positioning the reinforcement element during assembly.
DETAILED DESCRIPTION OF THE INVENTION
[0016] 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.
[0017] FIG. 2 illustrates a prior art seat frame 20 in which a
closed, multi-piece full perimeter tube 26, which is closed on it
self and forms an "L" outlining a base and seat back for the bus
seat frame 20. A full 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.
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. 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.
[0018] Referring to FIG. 3, an assembled modular school bus seat
frame 40 is illustrated supported in part from the floor 42 (shown
in phantom) and along interior bus wall 44 (shown in phantom) from
a chair rail 62 formed along the interior 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
illustrated in FIG. 2 in that they form more of the seat frame than
is traditional in school bus applications. 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 ended, 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 an upside down U shaped structural member mounted at
opposite ends in necks 50 and 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 and fit into the risers to form
joints. Risers 46 and 48 are molded elements with interior (i.e.
facing) sides which are contoured to reinforce the riser.
[0019] FIG. 4 is an exploded view of the modular seat frame 40
which shows the major structural members of the seat frame. Necks
50 provide the location of the junction between the ends of the
seat back perimeter tube 52 and the risers and are the locations
where variable length reinforcement members 64 are located upon
assembly of the seat frame 40. Necks 50 are C-channel sections
extending upwardly from the upper rearward areas of aisle riser 46
and wall riser 48 and formed during the stamping process used to
fabricate the risers. The open faces of the necks 50 face one
another. Partial perimeter tube 52 fits by its opposite ends into
the necks 50. The joints formed by joining the ends of the
perimeter tube 52 to the necks 50 are reinforced by addition of
reinforcement members 64 which fit into the neck 50 sandwiched
between the tube 52 and the interior of the necks 50. Bolts 66 are
inserted through the walls of the necks 50, reinforcement members
64 and the ends of perimeter tube 52 to complete the assembly.
[0020] 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.
[0021] 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.
[0022] 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.
[0023] FIGS. 5 and 6 illustrated the variable length reinforcement
member 64 and its use to construct a joint having controllable
deformation and flexure characteristics. As already noted,
reinforcement member 64 fits sandwiched between the perimeter tube
52 and necks 50 of risers 46 and 48 (only riser 46 is illustrated,
though the member would typically be used identically with riser
48). The length of the reinforcement members 52 can be varied, and
features such as holes 92 can be added to limit the members'
strength, and increase the amount of energy that is absorbed at the
joint. This further allows control of where bending takes place
during a rear impact against the seat frame 40. Frames 40 can now
be built which exhibit variation in height and width, with the
differences in loads that they experience under conditions of
impact handled by changes in the reinforcement member 64. The
risers are typically an aisle riser 46 and a wall riser 48, though
nothing would prevent use of the invention with a full width seat
using opposed wall risers or a seat built on two aisle risers.
Hence, in the claims the risers are referred to as first and second
risers without differentiation regarding which type of riser is
used.
[0024] In one embodiment, reinforcement member 64 is a three sided
sleeve having opposed legs 90 and an open face, with examples
positioned on the ends of perimeter tube 52 by welds 100. After
introduction of the ends of perimeter tube into risers 50, the
reinforcement member 64 is sandwiched between a lower riser
stamping (46, 48) and the upper seat partial perimeter tube 52 with
its open face aligned with the open side of the neck 50 in which it
is situated. Thus the member 64 is located at the joint formed
between the necks 50 and the ends of the partial perimeter tube 52.
It overlaps the tube 52 of the upper frame, and extends above the
joint for a distance that is varied according to the loading
characteristics that are required. It can also be extended
downward. Holes 92 are provided through which bolts 66 can be
positioned and which strategically weaken the reinforcement member
64 at the desired locations. Members 64 are positioned to align
holes 92 with holes 122 (see FIG. 7) through the ends of partial
perimeter tube 52 and with holes 104 through the necks 50. In the
embodiment illustrated in FIG. 5, member 64 is also attached to
tube 52 using spot MIG (Metal in Inert Gas) welds. In effect, the
seat frame can be tuned for strength characteristics between the
lower seat and the seat back frame, and the degree of allowed
deformation controlled, with the use of only two reinforcement
members.
[0025] FIGS. 5 and 6 illustrated the variable length reinforcement
member 64 and its use to construct a joint having controllable
deformation and flexure characteristics. As already noted,
reinforcement member 64 fits sandwiched between the perimeter tube
52 and necks 50 of risers 46 and 48 (only riser 46 is illustrated,
though the member would typically be used identically with riser
48). The length of the reinforcement members 52 can be varied, and
features such as holes 92 can be added to limit the members'
strength, and increase the amount of energy that is absorbed at the
joint. This further allows control of where bending takes place
during a rear impact against the seat frame 40. Frames 40 can now
be built which exhibit variation in height and width, with the
differences in loads that they experience under conditions of
impact handled by changes in the reinforcement member 64. The
risers are typically an aisle riser 46 and a wall riser 48, though
nothing would prevent use of the invention with a full width seat
using opposed wall risers or a seat built on two aisle risers.
Hence, in the claims the risers are referred to as first and second
risers without differentiation regarding which type of riser is
used.
[0026] In its preferred embodiment, reinforcement member 64 MIG
welded to the inside of neck 50 with its open side coinciding with
the open side of the neck. Both neck 50 and reinforcement member 64
are three sided sleeves and an open face. Upon assembly, the
reinforcement member becomes sandwiched between the lower riser
stamping (46, 48) and the upper seat partial perimeter tube 52 as
in the prior embodiment. Again the member 64 is located at the
joint formed between the necks 50 and the ends of the partial
perimeter tube 52. It overlaps the tube 52 of the upper frame, and
extends above the joint for a distance that is varied according to
the loading characteristics that are required. It can also be
extended downward. Holes 92 of the reinforcement member 52 are
provided through which bolts 66 can be positioned and which
strategically weaken the reinforcement member 64 at the desired
locations. Members 64 are positioned to align holes 92 with holes
122 through the partial perimeter tube 52 and with holes 104
through the necks 50. Member 64 is also attached to the inside of
neck 50 using spot MIG (Metal in Inert Gas) welds.
[0027] 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.
* * * * *