Passive seat belt system integrated with a seat

An arm assembly is movable from a stowed position adjacent one side of a vehicle seat toward the occupant to restrain the occupant in the seat and movable away from the occupant to the stowed position. The arm assembly has a first length when in the stowed position and a second length when restraining the occupant. The first length when the arm assembly is in the stowed position is less than the second length of the arm assembly when restraining the occupant. A motor-driven linear actuator moves the arm assembly from and to the stowed position.

BACKGROUND OF THE INVENTION 
1. Technical Field 
The present invention relates to a passive seat belt system for use in a 
vehicle, and particularly relates to a passive seat belt system integrated 
with a seat of a vehicle. 
2. Background Art 
A known passive seat belt system integrated with a vehicle seat is 
disclosed in U.S. Pat. No. 3,794,135. The seat belt system of U.S. Pat. 
No. 3,794,135 includes an articulated lap belt. The articulated lap belt 
has a plurality of hollow segment members hingedly connected to each 
other. A spring strip passes through the hollow segment members. When 
tension is applied to the spring strip, the hollow segment members pivot 
relative to each other to bring the articulated lap belt around the 
occupant. When tension is released from the spring strip, the hollow 
segment members pivot relative to each other and the articulated lap belt 
moves away from the occupant. 
Another known passive seat belt system integrated with a vehicle seat is 
disclosed in U.S. Pat. No. 3,901,550. The seat belt system of U.S. Pat. 
No. 3,901,550 includes a pair of upper guard arms and a pair of lower 
guard arms. The upper and lower guard arms cooperate to restrain an 
occupant seated in a vehicle seat. A spring strip is attached to a guard 
arm and urges the guard arm to a straight stored position when the guard 
arm is not in use. One end of a tension strap is attached to the guard 
arm. The other end of the tension strap is secured to a reel. A drive 
winds the tension strap onto the reel to bend the guard arm around an 
occupant seated in the vehicle seat. 
SUMMARY OF THE INVENTION 
In accordance with the present invention, an apparatus restrains an 
occupant in a seat of a vehicle. The apparatus comprises an arm movable 
from a stowed position adjacent one side of the seat toward the occupant 
to restrain the occupant in the seat. The arm is also movable away from 
the occupant to the stowed position. The arm includes a plurality of links 
interconnected end-to-end. The links are pivotable relative to each other 
and movable longitudinally relative to each other. The links pivot and 
move longitudinally relative to each other in one direction as the arm 
moves away from the occupant to the stowed position. The links pivot and 
move longitudinally relative to each other in the opposite direction as 
the arm moves from the stowed position toward the occupant to restrain the 
occupant in the seat. 
The arm has a first length when in the stowed position and a second length 
when restraining the occupant. The first length is less than the second 
length because the links are longitudinally contracted relative to each 
other when the arm is in the stowed position and are longitudinally 
extended relative to each other when the arm is restraining the occupant. 
Preferably, a motor-driven linear actuator operatively coupled with the 
arm moves the arm from and to the stowed position.

DESCRIPTION OF PREFERRED EMBODIMENT 
As representative of the present invention, FIGS. 1-2 and 7 illustrate a 
seat belt system 10 integrated with a seat 12 of a vehicle. The seat belt 
system 10 includes a buckle assembly 14 secured to the seat 12 of the 
vehicle. The buckle assembly 14 is located on the outboard side of the 
seat 12. A first linear actuator 16 is secured to the outboard side of the 
seat 12 and is operatively coupled with the buckle assembly 14 for moving 
the buckle assembly 14 between a stored position and a non-stored 
position. The non-stored position of the buckle assembly 14 is away from 
the first linear actuator 16 and the stored position of the buckle 
assembly 14 is toward the first linear actuator 16. 
The first linear actuator 16 is controlled to operate in opposite 
directions. One direction of operation of the first linear actuator 16 
corresponds to the direction of movement of the buckle assembly 14 towards 
its non-stored position. The other direction of operation of the first 
linear actuator 16 corresponds to the direction of movement of the buckle 
assembly 14 towards its stored position. As shown in FIG. 7, the buckle 
assembly 14 is in its stored position. The first linear actuator 16 may be 
an electromechanical linear actuator in the Electrak 1 Series manufactured 
by Warner Electric, Motion Control Systems Division, located in Marengo, 
Ill. 
The seat belt system 10 further includes an arm assembly 18. The arm 
assembly 18 is movable from a stowed position as shown in FIG. 1 to a 
restraining position as shown in FIG. 2. The arm assembly 18 has a first 
length when it is in its stowed position. The arm assembly 18 has a second 
length when it is in its restraining position. The first length of the arm 
assembly 18 is less than the second length of the arm assembly 18. A latch 
assembly 20 is attached at one end of the arm assembly 18. The other end 
of the arm assembly 18 is fixed to a portion of the seat 12 of the 
vehicle. 
A second linear actuator 22 is secured to the inboard side of the seat 12 
and is operatively coupled with the arm assembly 18 for moving the arm 
assembly 18 between its stowed position and its restraining position, in a 
manner to be described later. The second linear actuator 22 is controlled 
to operate in opposite directions. One direction of operation of the 
second linear actuator 22 corresponds to the direction of movement of the 
arm assembly 18 towards its stowed position. The other direction of 
operation of the second linear actuator 22 corresponds to the direction of 
movement of the arm assembly 18 towards its restraining position. As shown 
in FIG. 7, the arm assembly 18 is in its stowed position. Like the first 
linear actuator 16, the second linear actuator 22 may also be an 
electromechanical linear actuator in the Electrak 1 Series manufactured by 
Warner Electric, Motion Control Systems Division, located in Marengo, Ill. 
Referring to FIG. 3, the arm assembly 18 includes a plurality of links 
interconnected end-to-end. The plurality of links includes a plurality of 
male segments 24 connected alternately with a plurality of female segments 
26. Preferably, each of the male and female segments 24, 26 is made of 
high-impact, wear-resistant material such as that sold under the brand 
name Delrin manufactured by E. I. DuPont de Nemours & Co., located in 
Wilmington, Del. 
In FIG. 3, two of the male segments 24 are individually labelled with 
reference numerals 24a and 24b. The specific construction of each of the 
male segments 24 is the same. For simplicity, only the male segment 24a is 
illustrated in detail in FIG. 4. 
Referring to FIGS. 3 and 4, the male segment 24a includes a central portion 
60a interconnecting two opposite end portions 62a, 66a. The central 
portion 60a has a first surface 63a and a second surface 64a which both 
face the end portion 62a. The second surface 64a is angled relative to the 
first surface 63a. The end portion 62a has an elongated slot 65a, which 
extends transversely through the end portion 62a for receiving a retaining 
pin 98 (shown in FIG. 3). The central portion 60a has similar first and 
second surfaces (not shown) which face the end portion 66a. The end 
portion 66a also has an elongated slot 67a for receiving a retaining pin 
97 (shown in FIG. 3) similar to the retaining pin 98. 
Similarly, in FIG. 3, two of the female segments 26 are individually 
labelled with reference numerals 26a and 26b. The specific construction of 
each of the female segments 26a, 26b is the same. For simplicity, only the 
female segment 26a is illustrated in detail in FIG. 5. 
Referring to FIGS. 3 and 5, the female segment 26a includes a central 
portion 70a having a bore 72a which extends lengthwise of the female 
segment 26a and through the central portion 70a for receiving a spring 28. 
Opening 80a and opening 90a are located at opposite ends of the bore 72a. 
The openings 80a, 90a both open upward and away from the central portion 
70a. A tapered surface 81a is located at the bottom of the opening 80a 
adjacent an end of the female segment 26a. Two through-holes 82a, 83a 
communicate with the opening 80a for receiving a retaining pin 99 (shown 
in FIG. 3), which extends between the two holes 82a, 83a. Similarly, a 
tapered surface 91a is located at the bottom of the opening 90a adjacent 
the other end of the female segment 26a. Two through-holes 92a, 93a 
communicate with the opening 90a for receiving the retaining pin 98, which 
extends between the two holes 92a, 93a. 
Referring to FIGS. 3, 4 and 5, assembly of the two male segments 24a, 24b 
with the female segment 26a is described below. The spring 28 is placed in 
the bore 72a of the female segment 26a. The end portion 62a of the male 
segment 24a is placed in the opening 90a of the female segment 26a. The 
retaining pin 98 is inserted through the holes 92a, 93a of the female 
segment 26a and the slot 65a of the male segment 24a to allow pivotal and 
longitudinal sliding movement of the end portion 62a in the opening 90a of 
the female segment 26a. Similarly, the end portion 66b (shown in FIG. 3 
only) of the male segment 24b is placed in the opening 80a of the female 
segment 26a. The retaining pin 99 is inserted through the holes 82a, 83a 
of the female segment 26a and the slot 67b (shown in FIG. 3 only) of the 
male segment 24b to allow pivotal and longitudinal sliding movement of the 
end portion 66b in the opening 80a of the female segment 26a. 
The two male segments 24a, 24b are located adjacent opposite ends of the 
female segment 26a and are spring-biased away from each other by the 
spring 28. More specifically, the spring 28 acts on the end portion 62a of 
the male segment 24a and on the end portion 66b of the male segment 24b to 
urge the male segments 24a, 24b apart from each other. Other male and 
female segments are interconnected in the same way. 
The male segments 24 and the female segments 26 are in longitudinally 
contracted or telescoped positions relative to each other, as shown in 
FIG. 3, when the arm assembly 18 is in its stowed position shown in FIG. 
1. The male segments 24 and the female segments 26 are in longitudinally 
extended positions relative to each other, as shown in FIG. 6, when the 
arm assembly 18 is in its restraining position shown in FIG. 2. The male 
and female segments 24, 26 pivot and slide longitudinally relative to each 
other when they move between their longitudinally contracted positions 
shown in FIG. 3 and their longitudinally extended positions shown in FIG. 
6. 
The pivoting and the longitudinal sliding movements of the male and female 
segments 24, 26 relative to each other are effected by controlling 
movement of an inside strap 30 and an outside strap 32, which are shown in 
FIGS. 3 and 6. As schematically illustrated in FIG. 7, one end 40 of the 
inside strap 30 is fixed to the buckle assembly 14. From the buckle 
assembly 40, the inside strap 30 extends around a number of turning bars 
42 and fixed pulleys 44 and through a channel (not shown) located under 
the seat 12. The inside strap 30 then extends through suitable guides (not 
shown) located on inside surfaces of the female segments 26. The inside 
strap 30 also extends through suitable guides (not shown) located on 
outside surfaces of the male segments 24. The other end 46 of the inside 
strap 30 is fixed to the end of the arm assembly 18 at which the latch 
assembly 20 is attached. Preferably, the inside strap 30 is made of nylon. 
One end 50 of the outside strap 32 is also fixed to the end of the arm 
assembly 18 at which the latch assembly 20 is attached. The outside strap 
32 extends through suitable guides (not shown) located on inside surfaces 
of the female segments 26. The outside strap 32 also extends through 
suitable guides (not shown) located on outside surfaces of the male 
segments 24. The outside strap 32 then extends around a movable pulley 54 
operatively connected to the second linear actuator 22. The other end 52 
of the outside strap 32 is fixed to a clamp 56 secured to the vehicle. 
Preferably, the outside strap 32 is made of nylon. 
When the arm assembly 18 is in its stowed position as shown in FIGS. 1, 3 
and 7, the second linear actuator 22 is in a position which pulls the 
outside strap 32 taut. When the outside strap is pulled taut, the male and 
female segments 24, 26 are fully contracted, as shown in FIG. 3, and 
pointed in a forward direction extending generally parallel with the 
inboard side of the seat 12. 
As shown in FIGS. 3 and 6, a molded cover 34 encloses the male and female 
segments 24, 26 and the inside and outside straps 30, 32. The cover 34 is 
preferably made of an expanded foam material made by the process of 
reaction injection molding (RIM). The cover 34 is secured to only the male 
or female segment farthest away from the second linear actuator 22. This 
permits the male and female segments 24, 26 to contract and extend freely 
within the cover 34. The cover 34 also provides resistance to movement of 
the male and female segments 24, 26 so that the arm assembly 18 is less 
limber and moves less erratically. 
A number of sensors and/or switches (not shown) are disposed at different 
locations around the seat 12 to provide signals indicative of certain 
vehicle seat conditions. For example, pressure switches are disposed along 
the length of the arm assembly 18 to detect respective pressures at the 
corresponding locations of the arm assembly 18 against an occupant in the 
seat 12. The signals from the pressure switches are monitored by a 
controller (not shown), such as a microprocessor, for providing control 
signals to each of the linear actuators 16, 22. 
When the vehicle ignition is turned on or when the vehicle door is closed, 
the two linear actuators 16, 22 actuate. The first linear actuator 16 is 
actuated to operate in the direction to move the buckle assembly 14 from 
its stored position to its non-stored position. The second linear actuator 
22 is actuated to operate in the direction to move the arm assembly 18 
from its stowed position shown in FIGS. 1, 3 and 7 to its restraining 
position shown in FIGS. 2 and 6. 
More specifically, with reference to FIG. 7, the second linear actuator 22 
operates in the direction to move the pulley 54 away from the second 
linear actuator 22. When the pulley 54 moves away from the second linear 
actuator 22, slack is provided in the outside strap 32. When slack is 
provided in the outside strap 32, the male and female segments 24, 26 
pivot and extend relative to each other due to their tendency to extend 
relative to each other. The male and female segments 24, 26 have a 
tendency to extend relative to each other because of the biasing force of 
the springs, such as the spring 28, located within the female segments 26. 
This biasing force acts between adjacent male segments to urge the male 
segments 24 apart from each other as previously described. 
When the male and female segments 24, 26 extend relative to each other, the 
length of the arm assembly 18 is maximized to permit the arm assembly 18 
to extend around a relatively large occupant in the seat 12. As the arm 
assembly 18 extends around the occupant in the seat 12, the latch assembly 
20 moves toward the buckle assembly 14. Thus, the arm assembly 18 extends 
around the occupant in the seat 12 and the latch assembly 20 moves toward 
the buckle assembly 14 when the second linear actuator 22 operates in the 
direction to move the pulley 54 away from the second linear actuator 22. 
At the same time the second linear actuator 22 is operated to move the 
pulley 54 away from the second linear actuator 22, the first linear 
actuator 16 is operated to move the buckle assembly 14 away from the first 
linear actuator 16 towards the latch assembly 20. Thus, while the arm 
assembly 18 is extending around the occupant and the latch assembly 20 is 
moving towards the buckle assembly 14, the buckle assembly 14 is moving 
towards the latch assembly 20. As the arm assembly 18 continues to extend 
around the torso of the occupant in the seat 12 and the latch assembly 20 
and the buckle assembly 14 continue to move towards each other, the latch 
assembly 20 is eventually introduced into the buckle assembly 14 and locks 
with the buckle assembly 14. 
After the latch assembly 20 is locked with the buckle assembly 14, each of 
the first and second linear actuators 16, 22 is signaled to operate in its 
opposite direction. When the first linear actuator 16 operates in its 
opposite direction, the buckle assembly 14 moves towards the first linear 
actuator 16. As the buckle assembly 14 moves towards the first linear 
actuator 16, slack is provided in the inner strap 30. When the second 
linear actuator 22 operates in the opposite direction, the pulley 54 moves 
towards the second linear actuator 22. When the pulley 54 moves towards 
the second linear actuator 22, slack is taken up in the outside strap 32 
and the outside strap 32 becomes taut. When slack is provided in the 
inside strap 30 and the outside strap 32 becomes taut, the male and female 
segments 24, 26 in the arm assembly 18 contract to desired lengths of 
extension corresponding to desired pressure of the arm assembly 18 against 
the occupant in the seat 12 to restrain the occupant in the seat 12. Thus, 
the arm assembly 18 extends around the occupant and adjusts itself to 
desired pressure against the occupant to restrain the occupant in the seat 
12 when either the vehicle ignition is turned on or the vehicle door is 
closed. 
When the occupant desires to egress from the seat 12, some or all of the 
switches and/or sensors disposed at different locations around the seat 12 
are activated so that the buckle assembly 14 unlocks and releases the 
latch assembly 20. At the same time the buckle assembly 14 unlocks and 
releases the latch assembly 20, the second linear actuator 22 operates in 
the direction to move the pulley 54 towards the second linear actuator 22 
so as to pull the outside strap 32 taut. When the latch assembly 20 is 
released from the buckle assembly 14 and the outside strap 32 is pulled 
taut, the male and female segments 24, 26 pivot and longitudinally 
contract relative to each other. The male and female segments 24, 26 pivot 
and longitudinally contract relative to each other because the amount of 
tension in the outer strap 32 is sufficient to compress the springs, such 
as the spring 28, located within the female segments 26. When this occurs, 
the arm assembly 18 moves back to its stowed position as shown in FIGS. 1, 
3 and 7 to allow the occupant to egress from the seat 12. 
By interconnecting the male and female segments 24, 26 within the cover 34 
and using the first and second linear actuators 16, 22 to control 
longitudinal extension and longitudinal contraction of the male and female 
segments 24, 26 in the manner described hereinabove, an improved seat belt 
system is provided and a number of advantages result. One advantage is 
that the seat belt system automatically positions, locks, and adjusts 
itself around the occupant in the seat 12. Another advantage is that the 
arm assembly 18 is less in the way of the occupant when the arm assembly 
18 is in its stowed position since the arm assembly 18 has a shorter 
length in the stowed position than in the restraining position. 
From the above description of the invention, those skilled in the art will 
perceive improvements, changes and modifications. Such improvements, 
changes and modifications within the skill of the art are intended to be 
covered by the appended claims.