Land vehicles – Wheeled – Attachment
Reexamination Certificate
2001-09-26
2003-04-15
Dickson, Paul N. (Department: 3616)
Land vehicles
Wheeled
Attachment
C280S801100, C280S806000
Reexamination Certificate
active
06547273
ABSTRACT:
BACKGROUND
1. Field of the Invention
The present invention relates generally to vehicle occupant restraint systems, and more particularly, to a seat belt restraint system that incorporates an inflatable section into the torso section of the belt.
2. Background of the Invention
Inflatable seat restraint systems have proven to be a dramatic improvement over ordinary three-point seat belts. Unlike ordinary belts, these systems incorporate inflatable restraints that fill with gas immediately upon vehicle impact. The inflatable restraints pretension the systems with a force sufficient to counter body loading, to restrict occupant motion during a crash, and to distribute crash loads over larger occupant surface area, thus minimizing injury.
FIGS. 1
a
-
1
e
illustrate a typical prior art inflatable seat restraint system, as disclosed in the commonly assigned U.S. Pat. No. 5,839,753 to Yaniv et al., which is incorporated by reference herein. The system includes lap belt
102
, shoulder or torso belt
103
, including an inflatable restraint
101
, buckle assembly
105
, anchor
106
, anchored inertia reels
117
and
118
, gas generator
122
, and a sensor assembly (not shown).
As shown in
FIG. 1
c,
lap belt
102
and shoulder belt
103
form one continuous strap which passes through the male portion of buckle assembly
105
. Lap belt
102
is designed to restrict the forward motion of a seated occupant at the pelvis. Lap belt
102
is connected to anchored inertia reel
117
, which pivotally mounts lap belt
102
to the floor or seat structure on the door-side of seat
121
(as shown in
FIGS. 1
a
and
1
b
). The other end of lap belt
102
loops through the male portion of buckle assembly
105
, so that the length of lap belt
102
can be adjusted to accommodate a wide range of occupant sizes.
The female portion of buckle assembly
105
is attached to buckle strap
107
. Buckle strap
107
is pivotally mounted to an attachment point in the vehicle, such as the base of seat
121
, or a floor structure on the side of seat
121
that is farthest from the door, by anchor
106
. The female and male portions of buckle assembly
105
fasten together, thus securing seat belt system
110
around the occupant in a manner similar to that of conventional three-point seat belt systems.
As shown in
FIG. 1
d,
gas generator
122
is typically mounted inside the seat back. The gas generator is also sometimes located in the seat base. Durable tubing
116
provides a fluid path from gas generator
122
to inflatable restraint
101
.
As shown in
FIG. 1
c,
inflatable restraint
101
is attached to shoulder belt
103
and extends diagonally from the occupant's hip to behind and above the occupant's shoulder. The upper end of inflatable restraint
101
loops through a D-ring
108
that is mounted to seat
121
as shown (
FIG. 1
d
) or to the vehicle (e.g., at the roof rail or at the upper B-pillar area (not shown)). D-ring
108
acts as an intermediate guide for shoulder belt
103
, setting the height at which shoulder belt
103
wraps over the occupant's shoulder. Shoulder belt
103
is then anchored to seat
121
or the vehicle (not shown) by an inertia reel
118
.
As shown in
FIG. 1
a,
shoulder strap
103
is routed inside the vehicle seat to inertia reel
118
, which is mounted in the lower portion of the seat back. Thus, as shown in
FIGS. 1
b
and
1
d,
tubing
116
provides fluid communication from the gas generator to inflatable restraint
101
in the torso of the restraint system.
As best shown in
FIG. 1
d,
when a collision occurs, the crash sensor sends a signal to the initiator in gas generator
122
. The initiator then ignites the gas generator
122
, which forces gas through durable tubing
116
and into inflatable restraint
101
. As the gas flows into inflatable restraint
101
, the internal pressure causes the tube diameter to increase and the tube length to decrease. At the same time, seat belt system
110
is constrained on the outboard side by inertia reel
117
and on the inboard side by anchor
106
, and behind the shoulder by inertia reel
118
. Inertia reels
117
and
118
lock up during impact, preventing payout of the belt. Thus, as inflatable restraint
101
contracts, it pulls any slack out of seat belt system
110
. The occupant is thus provided with a pretensioned seat belt, which restricts the forward motion of the occupant and reduces primary injuries.
Typically, conventional inflatable seat belt restraint systems mount inflators in one of two locations: 1) either behind the seat for inflation from behind the occupant and over the shoulder, or 2) at the buckle for inflation from the buckle up to the occupant's shoulder. The inflatable seat restraint system of
FIGS. 1
a
-
1
e
is an example of this first configuration, which is referred to herein as the shoulder-fill design. The second configuration is referred to herein as the buckle-fill design. As used herein, inflator means any device that fills an inflatable restraint during system deployment, e.g., a gas generator.
For both the shoulder-fill and buckle-fill designs, providing shoulder belt height adjustment to accommodate different torso lengths is a significant concern. To provide maximum occupant protection, the intermediate guide for the shoulder belt (e.g., D-ring
108
in
FIGS. 1
a
-
1
e
) must not be below or too far above the occupant's shoulder. Indeed, most manufacturers and safety experts recommend that the intermediate guide be positioned at or above an occupant's shoulder, with a maximum shoulder belt angle of 30° above horizontal. Such shoulder belt height adjustments are simple for conventional three-point seat belt systems, which have no inflatable restraints. However, substantial difficulties arise when incorporating sections of inflatable restraint.
For example, shoulder-fill designs, such as the design illustrated in
FIGS. 1
a
-
1
e,
mount the inflator in a fixed position and use a high-pressure hose to connect the inflator to the inflatable restraint. The high-pressure hose is flexible to accommodate shoulder belt height adjustments, e.g., when D-ring
108
is raised to wrap the belt over an occupant with a longer torso. Although this shoulder-fill design permits moderate shoulder belt height adjustment, the inflatable restraint must pass through the intermediate guide. Because the inflatable restraint tends to be bulky and stiff, the inflatable restraint and the webbing to which it is attached often kink and bunch around the intermediate guide. In addition, the small diameter of a typical intermediate guide (e.g., a D-ring) pinches the inflatable restraint and webbing. These restrictions cause uneven travel and deployment of the inflatable restraint, resulting in inadequate occupant protection. Although providing stronger clock springs on the inertia reel that feeds the webbing may help force the inflatable restraint over the intermediate guide and reduce kinking and bunching, the stronger pull compromises occupant comfort.
In an attempt to accommodate different height adjustments, designers have proposed various modifications to the shoulder-fill design, each with significant drawbacks. Such modifications have included inflators attached directly to the webbing, inflators mounted on linear slides or guides, and inflators mounted on swing arm devices. In providing a degree of shoulder belt height adjustment, each modification compromises occupant comfort or safety in some way. For example, in the systems that move the inflator in concert with the movement of the inflatable restraint, difficulty in sliding or translating the inflator is a common problem.
In addition, shoulder-fill systems that attach the inflator directly to the webbing encounter undesirably high inertial loading during webbing retraction and payout, and during crash events. Installing counterweights and springs can offset this high inertial loading, but requires more parts, increased complexity, and higher costs.
Shoulder-fill systems that mount the inflator on a linear slide can reduce
Grace Gregory B.
Olson Brent K.
Dickson Paul N.
Fleming Faye M.
Shaw Pittman LLP
Simula Inc.
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