Supplemental restraint side air bag apparatus for vehicle

A side air bag apparatus installed within a seat has an air bag unit containing an inflator and a folded air bag in an air bag unit housing which is connected to a firing control unit by way of a harness partly extending from the air bag unit within and along a lower transverse section of the seat from one side of the seat close to a door to the other side of the seat and partly extending under the seat to the firing control unit via a coupler secured to the underside of the seat.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to an air bag apparatus as a supplemental restraint 
air bag apparatus for a vehicle, and, more particularly, to a side air bag 
apparatus having an air bag unit connected to a firing control device 
through a harness. 
2. Description of Related Art 
An air bag apparatus installed in the inside of a steering wheel serves as 
a supplemental restraint air bag apparatus to protect a driver sitting on 
the driver's seat and fastened by a seat belt upon an occurrence of a 
frontal collision. In recent years, in order to protect drivers and/or 
passengers against side collision, it is becoming widespread to provide a 
side air bag apparatus with an air bag unit installed in a seat. Such a 
side air bag apparatus is known from, for example, Japanese Unexamined 
Patent Publication No. 6-64491. 
Air bag unit is typically installed in a side section of a seat close to a 
side door of the vehicle so as to expand the air bag between the passenger 
sitting on the seat and the door adjacent to the passenger, protecting a 
collision of the passenger against the door. In cases where the air bag 
unit is installed adjacently to the door close to the seat, it is general 
to lay a harness for transmitting a firing signal from a firing control 
unit to the air bag unit in the inside of the door. In such a case, 
because, if the seat is deformed at the side section adjacent to the door 
due to a lateral collision, the harness is possibly strongly tugged and 
tensed, there is a strong demand for protection against lateral collision. 
SUMMARY OF THE INVENTION 
It is accordingly an object of the invention to provide a side air bag 
apparatus installed within a seat of a vehicle as a supplemental restraint 
system in which an air bag unit is connected to a firing control unit by 
way of a harness free from tension even when the seat is deformed upon an 
occurrence of a lateral collision of the vehicle. 
The above object of the invention is accomplished by providing a side air 
bag apparatus installed as a supplemental restraint system within a seat 
of a vehicle which comprises an air bag unit installed within a side 
section of a seat close to a vehicle door and a firing control device 
disposed separately from the air bag unit and the seat for generating a 
firing signal in response to a lateral collision of the vehicle. A harness 
through which a firing signal is transmitted to the firing control device, 
in particular a inflator within the air bag unit, from the firing control 
unit is laid to partly extend within the seat in a transverse direction of 
the vehicle from the air bag unit toward a center of the vehicle. 
The air bag unit may be installed within a side section, such as a bolster, 
of a seatback or a seat cushion of the seat. In the case where the air bag 
unit is installed within the seatback, the harness extends within the 
seatback downward from the air bag unit and then toward an opposite side 
section remote from the vehicle door along a lower section of the 
seatback. A coupler may be attached to a front underside of a seat cushion 
of the seat which coupler connects a part of the harness extending from 
the air bag unit and a part of the harness extending to the firing control 
unit. The harness may be laid and extends along a lower transverse section 
extending along the lower section of the seatback of a seatback frame 
member as a seatback reinforcement. Further, the harness may be partly 
attached to a transverse member disposed within the seatback and extending 
along the lower transverse section of the seatback frame member. 
With the side air bag apparatus as a supplemental restraint system 
according to the invention, the harness laid to partly extend within the 
seat in a transverse direction of the vehicle from the air bag unit toward 
the center of the vehicle is adapted to loosen as the seat is deformed due 
to a lateral collision of the vehicle. Accordingly, the harness is 
prevented from receiving tension, and hence put under well protection. 
Furthermore, because the air bag unit is installed within the seatback 
bolster, or the seat cushion bolster, of the seat which provides a 
relatively large space, the air bag unit is installed in the seat without 
an effect of losing a pleasant sitting feeling. In addition, because the 
harness partly extending from the air bag unit and partly extending from 
the left firing control unit is connected by means of the coupler secured 
to the front underside of the seat cushion, it is made possible to prepare 
the seat with the harness and the coupler connected to the harness and 
secured to the seat cushion in advance, and to connect the harness 
extending from the firing control unit to the coupler during installing 
the seat into the vehicle. The harness extending from the firing control 
unit is quite easily connected to the coupler. The coupler secured to the 
underside of the seat cushion is hard to be kicked and significantly 
damaged by a foot of the passenger sitting on the rear seat. This layout 
of the harness not only provides improved convenience of assembling the 
harness and the coupler to the seat and installing the seat into the 
vehicle but also put the harness and the coupler under improved protection 
.

DETAILED DESCRIPTION OF THE SPECIFIC EMBODIMENT 
Referring to the drawings in detail, particularly to FIGS. 1 and 2 which 
show, by way of example, a front left passenger's seat 1 with an side air 
bag apparatus installed therein. The seat 1 comprises a seat cushion 2, a 
seatback 3 and a head restraint 4. The seat cushion 2 at each of the 
opposite sides is provided with a slider bar 7 secured to the under side 
thereof. The slide bars 7 are put on a pair of parallel guide rails 8 for 
slide movement in a longitudinal direction from front to back of a vehicle 
and locked to adjust the seat 1 in a desired longitudinal position. Each 
side rail 8 at its front and rear ends is secured to a floor panel (not 
shown) by means of brackets 10. A knuckle mechanism 9 connects these seat 
cushion 2 and seatback 3 so that the seatback 3 is folded and unfolded 
between a flat position and an upright position. The seatback angle is 
changed by means of a seatback angle adjustment mechanism (not shown). The 
knuckle mechanism 9 comprises a bracket 9a secured to each rear end of the 
seat cushion 2, a transverse hinge shaft 9b supported by the brackets 9a, 
and a knuckle arm 9c secured to each side of the seatback 3. The head 
restraint 4 has a generally U-shaped frame 5 having a pair of pipe-shaped 
guide legs 5a which extend out of the head restraint 4 and are received by 
a head restraint vertical adjustment cylinders 14 for vertical position 
adjustment. The head restraint 4 is pulled up to be raised or pushed down 
to be lowered. The seatback 3 at its rear section is encircled and 
reinforced by a rectangularly-shaped seatback frame member 13 made of a 
steel pipe. The seatback frame member 13 is shaped to conform to the shape 
of the seatback 3. One of the vertical side sections 13V extends along the 
left side of the seatback 3. The seatback frame member 13 at its upper 
transverse section 13U securely supports the head restraint vertical 
adjustment cylinders 14. 
As clearly shown in FIGS. 3 and 4, the seatback 3 is provided with a 
plurality of, for example five in this embodiment, wire strings 18 
transversely extending between and welded, or otherwise secured, to side 
vertical sections 13V of the seatback frame member 13. This wire string 18 
has a diameter smaller than that of the steel pipe of the seatback frame 
member 13. A seatback pad 15 is supported in such a way as to hold the 
seatback frame member 13 at the rear side sections from the side to the 
back. The wire strings 18 bears up the seatback pad 15 so as to prevent 
the seatback pad 15 from sinking backward when the person sitting on the 
seat 1 leans against the seatback 3. The seatback pad 15 comprises an 
urethane foam core pad 17 and an urethane foam cover pad 16 softer than 
the urethane foam core pad 17. The seatback 3 at its back is empty behind 
the wire strings 18 and covered by a thin outer cloth cover 19. 
As seen in FIG. 1, the seat cushion 2 has a seat cushion side bolster 2a 
swelled upward at each side, and the seatback 3 has a side bolster 3a 
swelled forward at each side. 
Seat 1 is provided with an air bag unit 21 installed within one of the 
seatback side bolsters 3a of the seatback 3, which is adjacent directly to 
a left door 40 (see FIG. 7) of the vehicle, for holding the passenger 
sitting on the seat 1. The air bag unit 21 is positioned in close 
proximity to the side vertical section 13V of the seatback frame member 
13. As shown in FIG. 6, the air bag unit 21 comprises a unit housing 23 
having a U-shaped cross-section and serving as a reaction can, a hollow 
cylinder inflator 23 containing firing mechanism and an explosive (both 
not shown) therein, and a folded air bag 24. The front opening 25 of the 
unit housing 23 is closed by paper. A first harness 51 extends from the 
firing mechanism to a left side air bag firing control unit 61 connected 
to a lateral acceleration sensor (not shown). When the firing control unit 
61 sends a firing signal to the firing mechanism of the inflator 23 in 
response to detection A of a lateral collision of the vehicle by the 
lateral acceleration sensor, the inflator 23 fires the explosion to 
produce and blows a large amount of gas by which the air bag 24 is 
instantaneously inflated and expanded forward tearing the papered front 
opening 25 of the unit housing 22. 
Unit housing 22 has front verges 22a, the inner or right one of which is 
formed with an upper half section sloped backward. The air bag unit 21 is 
installed within a space 33 formed in the inside of the left seatback side 
bolster 3a of the seatback pad 15. Specifically, the air bag unit 22 is 
placed in such a position as to put the inflator 23 in close proximity to 
the left side vertical section 13V of the seatback frame member 13 and 
direct the papered front opening 25 forward left. The entire air bag unit 
21 is in the inside space defined by vertical planes VP perpendicularly 
intersecting to each other and externally contact with the outer surface 
of the left side vertical section 13V of the seatback frame member 13. 
Further, the air bag unit 22 is declined upward with respect to the floor 
of the vehicle so as to direct the papered front opening 25 slightly 
upward with respect to a horizontal plane when the seatback 3 is adjusted 
with respect to the seat cushion at a regular angle appropriate for the 
passenger sitting on the seat 1. The space 33 is specifically defined by 
an inner wall 33a in the left seatback side bolster 3a. In the space 33, a 
bracket frame 30 extends along and secured to the left side vertical 
section 13V of the seatback frame member 13 from the inside. On the other 
hand, the air bag unit 21 is provided with a pair of fitting staples 26 
welded, or otherwise secured, to the side wall of the unit housing 22. The 
air bag unit 21 is bolted by fixing bolts 27 and 28 and nuts, or otherwise 
secured, to the bracket frame 30. In such a way, the air bag unit 21 is 
rigidly supported by the seatback frame member 13. The bracket frame 30 at 
its lower end is bolted, or otherwise secured, to the knuckle arm 9c of 
the knuckle mechanism 9 installed in the seat 1. The seatback pad 15 is 
formed with an vertical notch 33b or a vertical groove in the inner wall 
33a facing the papered front opening 25 of the unit housing 22 of the air 
bag unit 21 placed in the space 33. This vatical notch 33b faces directly 
the papered front opening of the unit housing 22 of the air bag unit 21 
and has a vertical length slightly longer or approximately equal to the 
length of the unit housing 22 of the air bag unit 21. Further, the 
seatback pad 15 has a seam 19a on the horizontal extension of the vertical 
notch 33b and formed in the outer cloth cover 19. Part of the seatback pad 
15 thus structured is easily torn and broken starting the vertical notch 
33b toward the seam 19a as expansion of the air bag 24 progresses, and 
finally opens along the seam 19a to permits the air bag 24 still expanding 
to jut out of the seatback 3 through the opening. The urethane foam core 
pad 17 along the space 33 which faces the air bag unit 21 is provided with 
a felt pad 38 integrally secured thereto. The utilization of the felt pad 
38 prevents part of the urethane foam core pad 17 from flying off when it 
is shaved off due to expansion of the air bag 24 and prevents dins caused 
due to a rub between the air bag unit 21 and the urethane foam core pad 17 
of the seatback pad 15. 
As seen in FIGS. 2 and 3, a harness fitting member 50 is installed within 
the lower section of the seatback 3. This harness fitting member 50 has a 
middle section 50a and opposite side sections 50b. The middle section 51a 
of the harness 51 extends along the lower transverse section 13L of the 
seatback frame member 13. Each side section 50b of the harness fitting 
member extends upward and outward and is secured to the side vertical 
section 13V of the seatback frame member 13 at appropriated height. The 
first harness 51 extends downward along the side section 50b of the 
harness fitting member 50 from inflator 23 of the air bag unit 21 and then 
transversely along the middle section 50a. As seen in FIG. 3, the first 
harness 51 at its middle and opposite end sections is fastened to the 
harness fitting member 50 by means of fastening plastic bands 55. The 
first harness 51 further extends downward at the right side end of the 
seatback 3 and enters into the seat cushion 2. As shown in FIG. 5, within 
the seat cushion 2, the first harness 51 extends forward along the right 
side slider bar 7 and then turns inward at the front end of the seat 
cushion 2 to a coupler 53 secured to the under side of the seat cushion 2 
at a transversely middle position. At the coupler 53 couples the first 
harness 51 and a second harness 52 extending another firing control unit 
(not shown) for the right side air bag. The first harness 51 is secured to 
the underside of the seat cushion 2 and the right side slider bar 7 by 
means of plastic clips 56 as seen in FIG. 2. 
Second harness 52, connected to the coupler 53 at opposite side to the 
first harness 51, extends toward the vehicle floor under the seat cushion 
2 and creeps to the firing control unit for the right side air bag unit. 
In this instance, the second harness 52 has a sufficient length so as to 
have much slack between the coupler 53 and the vehicle floor, and to have 
no tension, even when the passenger's seat 1 is adjusted to its forward 
end position. 
As shown in FIG. 7 and 8, the air bag 24 expands vertically in a fashion of 
a generally rectangularly-shaped balloon between the left door 40 and the 
passenger 39 sitting on the seat 1 so as to extend over the upper body and 
the head of the passenger 39 sitting on the seat 1. 
FIG. 9 diagrammatically shows the total system of air bag apparatus 
installed in the vehicle. The vehicle V is provided with left and right 
side air bag apparatuses and a front air bag apparatus. The left and right 
side air bag apparatuses are independently controlled to be fired by the 
left and right firing control units (SFCU) 61L and 61R. Similarly, the 
front air bag apparatus is controlled to be fired by the front firing 
control unit (FFCU) 62 upon an occurrence of a frontal collision of the 
vehicle V. These side air bag firing control units (SFCU) 61L and 61R are 
installed near the front seats placed side by side. The front air bag 
firing control unit (FFCU) 62 is at a transversely center position in the 
front section of the vehicle. All these air bag firing control units (SFCU 
and FFCU) 61L, 61R and 62 are supplied with electric power from a battery 
(PB) 63 through power lines 65 via a fuse box (FB) 64. One of the power 
lines 65 extends to the right from the fuse box 64 and turns backward 
between the seats. The power line branches off into two branch lines and 
extend opposite directions to the respective side air bag firing control 
units (SFCU) 61L and 61R. The front and side air bag firing control units 
(FFCU and SFCU) 62, 61L and 61R are connected to one another by way of 
intercommunication lines 66. Diagnostic data of faults is sent to and 
gathered at the front air bag firing control unit 62 from the side air bag 
firing control units (SFCU) 61L and 61R. If there is a fault at any one of 
the side air bag firing control units (SFCU) 61L and 61R, the front air 
bag firing control unit (FFCU) 62 excites a warning lamp (WP) 67 to 
indicate the fault. The power lines 65 and intercommunication line 66 are 
bundled compactly. 
In operation of the side air bag apparatus of the embodiment as described 
above, in response to a firing signal generated by the lateral 
acceleration sensor upon an occurrence of a left side lateral collision of 
the vehicle, the left side air bag firing control unit (SFCU) 61L produces 
a firing signal and sends it to the firing mechanism of the inflator 23 
through the second harness 52 and the first harness 51 via the coupler 53. 
The firing mechanism fires the explosion in the inflator 23 to produce and 
blow a large amount of gas into the air bag 24. As a result, the air bag 
24 is rapidly inflated and expanded by the gas to tear the part of the 
seatback pad 15 at the vertical notch 33b. With rapid progress of 
expansion of the air bag 24, the part of the seatback pad 15 is torn and 
broken toward the seam 19a of the outer cloth cover 19 and finally opens 
the outer cloth cover 19 along the seam 19a, permitting the air bag 24 
still inflating and expanding to jut out from the seatback 3 and extend 
between the left door 40 and the passenger 39 sitting on the seat 1. 
In this instance, because of the wiring where the first harness 51 extends 
downward from the air bag unit 21 and then from the left side to the right 
side of the lower section within the seatback 3, the first harness 51 is 
prevented from loosing and being applied with tension even upon an 
occurrence of deformation of the seat cushion 2 and/or the seatback 3 due 
to a lateral collision of the vehicle V. Furthermore, because the first 
harness 51 creeps the lower of the seatback 3, the first harness 51 does 
not receive an external force from the seatback 3 even when the passenger 
sitting on the seat 1 leans on the seatback 3. In this way, the first 
harness 51 is not only well protected as usual but prevented from 
significant damages due to a lateral collision of the vehicle. 
Furthermore, because the power line 65 between the fuse box 64 and the 
left and right side air bag firing control units (SFCU) 61L and 61R and 
the intercommunication line 66 between front and left side air bag firing 
control units (FFCU and SFCU) 62 and 61 extend as a bundle along the 
lengthwise center line of the vehicle, these lines 65 and 66 are certainly 
prevented from snapping. 
FIGS. 10 and 11 shows an air bag apparatus installed as a supplemental 
restraint system for a driver in accordance with another embodiment of the 
invention. A driver's seat similar to the passenger's seat 1 has a seat 
cushion 102 comprising a cushioning pad 164, a plate-like seat cushion 
frame 142 onto which the cushioning pad 146 is attached, a side garnish 
143 secured to each side of the seat cushion frame 142, and a slider bar 
145 interposed between the seat cushion frame 142 and the side garnish 143 
at each side of the seat and slidable on a guide rail 144 disposed on the 
vehicle floor (not shown). The cushioning pad 146 is enclosed by an outer 
cloth cover 147. The seat 141 at each of its sides is formed with a seat 
cushion side bolster 141a swelled upward. An air bag unit 150 is installed 
within a space formed in the right side bolster 141a. This air bag unit 
150 is similar in structure and operation to that shown in FIG. 6 and 
comprises an air bag unit housing 153 having a U-shaped cross-section and 
serving as a reaction can, a hollow cylinder inflator 151 containing a 
firing mechanism and an explosive (both not shown) therein, and a folded 
air bag (not shown). The front opening 153a of the unit housing 153 is 
closed by paper. The air bag unit housing 153 is bolted, or otherwise 
secured, to the seat cushion frame 142 by means of a fitting bracket 154. 
A deflector 155 made of a thin steep plate is secured to the fitting 
bracket 154 and the air bag unit housing 153 so as to direct the air bag 
upward and slightly backward. The space 156 formed in the right side 
bolster 141a extends gradually narrowing backward so as to make the air 
bag expand easily backward. Part of the cushioning pad 146 facing the 
papered front opening 153a is formed with a vertical notch or vertical 
groove line 158 along which the cushioning pad 146 is easily broken, and 
the outer cloth cover 147 at that part is provided with a seam 157 along 
which the outer cloth cover 147 is torn by the air bag inflating and 
expanding. Accordingly, with progress of inflation and expansion of the 
air bag, the part of the cushioning pad 146 is opened along the weakened 
line and the seam 157 to permit the air bag to jut out of the seat cushion 
411. 
A first harness 51 extending from the air bag unit 150 is connected to a 
coupler 53 secured to the underside of the seat cushion 141, and a second 
harness 52 extends from the coupler 153 to a firing control unit 61. 
As described above, with the air bag unit 21 installed in the seatback 
bolster 3a of the seat 1 adjacent to the left door, since the first 
harness 51 extends vertically downward from the air bag unit 21 and then 
transversely to the right within the seatback 3, the first harness 51 is 
prevented from being applied with tension even upon an occurrence of 
deformation of the seat 1 due to a lateral collision of the vehicle V. 
Furthermore, because the air bag unit 21 is installed within the seatback 
bolster 3a of the seat 1 which provides a relatively large space, the seat 
1 does not loose a pleasant sitting feeling. 
In addition, because the first harness 51 extending from the air bag unit 
21 and the second harness 52 extending from the left side air bag firing 
control unit (SFCU) 61 are bundled by means of the coupler 53 secured to 
the front underside of the seat cushion 2, it is made possible to prepare 
the seat 1 with the first harness 51 and the coupler 53 connected to the 
first harness 53 and secured to the seat cushion 2 and connect the second 
harness 52 extending from the left side air bag firing control unit (SFCU) 
61 to the coupler 53 during installing the seat 1 into the vehicle. 
Because the coupler 53 is secured to the underside of the seat cushion 2, 
It is quite easy to connect the second harness 52 to the coupler 53. The 
coupler 53 secured to the underside of the seat cushion 2 is prevented 
from being kicked and significantly damaged by a foot of a passenger 
sitting on the rear seat. This arrangement not only provides improved 
convenience of assembling the first and second harnesses 51 and 52 and the 
coupler 53 to the seat 1 and installing the seat 1 into the vehicle but 
also put the first and second harnesses 51 and 52 and the coupler 53 under 
improved protection. 
Air bag unit 21 may be installed in a left side bolster 2a of the left seat 
1. In this instance, the air bag unit 21 is placed so as to direct the 
papered front opening 25 approximately upward, and the first harness 51 is 
connected to the coupler 53 after laying the first harness 51 from the air 
bag unit 21 to the right in the seat cushion 2. 
It is to be understood that the present invention may be embodied with 
various changes, modifications and improvements, which may occur to those 
skilled in the art, without departing from the spirit and scope of the 
invention defined in the following claims.