Passive seatbelt system

A passive seatbelt system wherein the outer end of the passenger restraining belt moves forward or backward, permitting passenger entrance or exit and to automatically fasten or unfasten the belt about the passenger. The passive seatbelt system further includes at least one elastic piece coupled to the outer end of the belt whose rigidity gradually decreases from the outer end of the belt towards the center of the belt whereby when the belt is fastened the belt separates sufficiently from the passenger while still being able to be fastened normally when the belt is automatically fastened.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to seatbelt systems and more particularly to passive 
seatbelt systems which automatically fasten a passenger restraining belt 
around the passenger after he has seated himself. 
2. Prior Art 
Since seatbelt systems protect the passenger by restraining him in times of 
vehicular emergency, the passenger's safety is greatly increased. Since 
there are difficulties such as donning, feeling of oppression while 
wearing the belt, etc., the proportion of the belt wearers is very low. 
For this reason, a passive seatbelt system which can automatically fasten 
the belt about the passenger after he has seated himself is presently 
proposed. 
An example of such a passenger seatbelt system is constructed such that the 
outer end of the passenger restrictive belt runs in a guide rail fastened 
to the roof side of the vehicle such that it can be moved forward or 
backward along the vehicle and the passenger restraining belt is caused to 
approach or move away from the passenger seat to thereby automatically 
fasten or unfasten the belt from the passenger. 
However, although these passive seatbelt systems cause the outer end of the 
seatbelt to move towards the front of the vehicle when the passenger 
enters or exits, the passenger sometimes comes into contact with the belt 
near the outer end of the belt which is immediately in front of the 
passenger during entering or exiting and this contact makes the passenger 
feel uneasy. Furthermore, as the outer end moves toward the front or rear 
of the vehicle during automatic unfastening or fastening, the belt may 
come into contact with the passenger's body, especially his face, causing 
an uncomfortable sensation. Furthermore, as a result of the belt coming 
into contact with the passenger's neck, face, etc. during driving, in 
times of vehicular emergency the belt may constrict about the passenger's 
neck thereby causing an unfortunate circumstance. 
SUMMARY OF THE INVENTION 
Accordingly, it is a general object of the present invention to provide a 
seatbelt system which not only does not give the passenger an 
uncomfortable feeling during entering or exiting but also does not come 
into contact with the passenger during automatic fastening or unfastening. 
It is still another object of the present invention to provide a passive 
seatbelt system which can securely and appropriately fasten the belt. 
In keeping with the principles of the present invention, the objects are 
accomplished by a unique seatbelt system wherein the other end of the 
passenger restraining belt moves forward or backward to automatically 
fasten or unfasten the belt about the passenger so that the passenger can 
enter or exit. The belt is provided with flexible pieces so that the 
rigidity of the belt decreases from the outer end towards the center 
whereby when the belt is unfastened, it separates sufficiently from the 
passenger while being able to assume a normal fastend condition when the 
belt is fastened.

DETAILED DESCRIPTION OF THE INVENTION 
Referring more particularly to the figures, shown in FIG. 1 is a first 
embodiment of a passive seatbelt system in accordance with the teachings 
of the present invention. In FIG. 1, one end of the passenger restraining 
belt 10 is wound up by the force of a retractor 14 which is contained on 
the inner side of the passenger seat 12. The outer end 16 of the belt 10 
is fastened to a slider by a shoulder anchor 18. Winder 14 contains an 
inertial locking mechanism which instantly stops the unwinding of the belt 
10 during a vehicular emergency. 
Slider 20 is fastened so that it can move forward or backward along the 
vehicle in guide rail 24 which is fastened to roof side member 22 of the 
vehicle. The slider 20 is moved forward or backward along the vehicle by 
operating system 26. The operating system 26, operating in response to a 
signal given by door opening or closing when the passenger enters, moves 
slider 20 in the direction of operation system 26 after the passenger has 
seated himself in the passenger seat 12, i.e. shoulder anchor 18 is moved 
towards the rear of the vehicle and belt 20 is automatically fastened 
about the passenger 28 who is seated in the passenger seat 12. 
Alternately, when the passenger exits, slider 20 is moved in a direction 
away from operating system 26, i.e. shoulder anchor 18 is moved towards 
the front of the vehicle forming a space for the passenger to exit between 
the belt 10 and the passenger seat 12. Between the operating system 26 and 
the slider 20 there is a wire, etc. for the purpose of transmitting the 
motive power of a motive system such as a motor, etc., mounted in the 
operating system 26. 
As shown in FIGS. 2 and 3, the outer end 16 of the passenger restraining 
belt 10 is fastened by being inserted through passenger slot 30 in the 
shoulder anchor 18, folded back and sewn with seams 32. The base part of 
the shoulder anchor 18 is fastened to slider 20 by two fastening bolts 34. 
Elastic pieces 36, 38, 40 and 42 are fastened to the end of shoulder 
anchor 18 by two fastening bolts 34. These elastic pieces 36 through 42 
are made from spring sheet having identical thickness and width. The 
length of the elastic pieces 36 through 42 are identified as L1, L2, L3 
and L4. L2, L3, and L4 are respectively twice, three times and four times 
as long as L1. Furthermore, if these elastic pieces 36 through 42 are 
thought of as a half leaf spring, the rigidity is set so as to decrease 
gradually toward the outer end so that if a binding force is applied to 
the outer end of the elastic piece 42, the amount of bending near the 
shoulder anchor 18 is extremely small and gradually increases as you move 
away from the shoulder anchor 18. The elastic pieces 36 through 42 extend 
slider 20 and are slightly inclined towards the front of the vehicle from 
the vertical. Furthermore the elastic pieces 36 through 42 are covered by 
the outer end 16 of the belt 10 which has been folded back through the 
slot 30 of the shoulder anchor 18 and are sealed inside outer end 16 by 
seams 32. 
By the above-described means, the passenger does not come directly into 
contact with the elastic pieces. Furthermore, if the passenger should come 
in contact with the outer end 16 which contains the elastic pieces 36 
through 42, the elastic pieces 36 through 42 will not cause injury of the 
passenger since they can bend. 
Furthermore, as shown in FIGS. 2, 6, it is desirable that the elastic 
pieces 36 through 42 basically hang below the slider 20 such that the 
outer end 16 can run along the side 44 of the vehicle and provide an 
appropriate space in between it and the head of the passenger 28. In 
operation, as the outer end 16 of the belt 10 and slider 20 move to the 
front of the vehicle before the passenger enters, a passenger entrance 
space is formed between the belt 10 and the seat 12 and the passenger 20 
may easily seat himself in the seat 12. After the passenger has seated 
himself, an operating system 26 moves the slider 20 towards the rear of 
the vehicle and the belt 10 approaches the passenger 28 seated in the seat 
12. As a result, passenger 28 is automatically placed in a fastened-in 
condition by the belt 10. However, as shown in FIG. 6, since the outer end 
16 of the belt 10 is shaped so as to run along the vehicle side 44 by the 
rigidity of the elastic pieces 36 through 44, the belt 10 does not come in 
contact with the head of the passenger 28 during this motion and the 
passenger may be comfortably brought to an automatically fastened-in 
condition by the belt 10. Fruthermore, since the belt 10 cannot constrict 
the neck of the passenger 28 after fastening, the passenger may be brought 
to a secure, appropriate, fastened-in condition. In addition, during a 
vehicular emergency, the unwinding of belt 10 is stopped by the operation 
of an inertial mechanism of a retractor 14 and the passenger's chest is 
restrained diagonally by the belt 10 and the passenger's safety is 
guaranteed. 
Next, when the passenger exits the vehicle and opens the door, the 
operating system 26 moves the slider 20 to the front of the vehicle and 
belt 10 is separated from the passenger seat 12 to form a passenger exit 
space. In somewhat the same way as the automatically fastened condition, 
since the outer end 16 is kept approximately vertical by the rigidity of 
the elastic pieces 36 through 42 as it moves towards the front of the 
vehicle, it does not come in contact with the passenger 28. Also, as shown 
in FIG. 1, as the passenger enters, outer end 16 is bent towards the front 
of the vehicle by the rigidity of the pieces 36 through 42 and, as shown 
in FIG. 6, a suitable distance is maintained relative to the passenger's 
head and the passenger does not come in contact with outer end 16 and a 
comfortable exit is possible. 
Referring now to FIG. 7, shown therein is the second embodiment of the 
present invention. In the second embodiment a plastic plate 46 is used 
instead of the elastic pieces 36 through 42. The plastic plate 46 has one 
end fastened through slot 30 of the shoulder anchor 13 while the other end 
protrudes in the direction of the center of the belt 10 in somewhat the 
same manner as the elastic pieces 36 through 42 of the prior embodiment 
and the width of the plastic plate decreases in this direction. Therefore, 
the rigidity of the plastic plate 46 decreases in somewhat the same manner 
as in the previous embodiment. Furthermore, in this second embodiment, the 
rigidity of the outer end 16 is greater near the shoulder anchor 18 and 
decreases towards the end of the plastic plate 46. 
Referring to FIG. 8, shown therein is the third embodiment of the present 
invention. In this third embodiment, rod-like elastic elements 48 and 50 
such as piano wire, etc. are sealed in the outer end of the belt 10 in 
somewhat the same manner in the first and second embodiments. Here, the 
length of the elastic piece 48 along the direction of the belt 10 is 
approximately half the length of the elastic piece 50. Furthermore, in 
this embodiment just as in the previous embodiments, the rigidity of the 
outer end 16 gradually decreases and results substantially like those of 
the previous embodiments are produced. In addition, in this third 
embodiment the rigidity of the belt 10 near its outer end may be gradually 
varied by using the elastic pieces of two different cross sections or by 
using the elastic pieces of different lengths. 
Referring to FIG. 9, shown therein is the fourth embodiment of the present 
invention. In this fourth embodiment a plastic cover 52 is used as the 
elastic material. Cross section of the plastic cover 52 is arranged and 
configured such that it wraps around the belt 10 with one end extending to 
the slider 20 and the other end towards the central part of the belt 10. 
Therefore, in somewhat the same manner as in the previous embodiment, this 
gives the rigidity to the outer end 16. Since the cross section area of 
the plastic cover 52 gradually decreases from the shoulder anchor 18 
towards the central part of the belt 10, the rigidity decreases just as 
the prior embodiments. Furthermore, in this fourth embodiment, since the 
rigidity of the outer end 16 gradually decreases, similar results to those 
of the prior embodiment are obtained. 
From the above description it should be apparent that while the 
construction is described in terms of being used in a passive seatbelt 
system which utilizes a retractor, it would be possible to utilize the 
present invention with passive seatbelts of other designs which may or may 
not use a retractor. 
Referring to FIGS. 10 through 13, shown therein is a fifth embodiment of 
the present invention. In this fifth embodiment, an engagement hole 56 is 
formed in a shoulder anchor 18A and this engagement hole 56 engages with a 
buckle device 60 which is fastened to the top rear corner of the passenger 
door 58. That is to say, the outer end 16 of belt 10 creates a fastened 
condition about the passenger when the door 58 is closed and separates 
from the seat 12 by moving towards the front of the vehicle along with the 
door 58 when the door 58 is opened so that the belt 10 may be unfastened 
from about the passenger. 
The buckle device 60 is a buckle substantially the same as used in normal 
seatbelt systems and a locking plate (not shown) engages the opening 56 of 
the shoulder anchor 18A. If the passenger presses the release button 62 
while belt 10 is fastened, shoulder anchor 18A is released from the buckle 
device 60, the belt 10 is released from the fastened condition and the 
door 58 may be opened to allow escape to the outside of the vehicle. 
Furthermore, a reinforcing plate 64 is provided and in times of vehicular 
emergency since a large extensive force is transmitted to the buckle 
device 60 by the belt 10, the reinforcing plate 64 transmits this force to 
the body of the vehicle to thereby stop damage to the buckle device 60. 
In this fifth embodiment, since the anchor 18A is fitted with elastic 
pieces 36 through 42 of different lengths as in the first embodiment, the 
rigidity of the outer end 16 gradually decreases as in the first 
embodiment and outer end 16 is separated from the passenger 28 when in the 
unfastened condition while still providing appropriate placement during 
the fastened condition. 
Referring to FIGS. 14 through 16, shown therein are six, seventh and eighth 
embodiments of the present invention. In these embodiments respectively 
are shown a plastic plate 46, elastic pieces 48 and 50 and a plastic cover 
52 similar to the second, third and fourth embodiments, respectively. Each 
of these six, seventh and eighth embodiments have a construction wherein 
there are fastened to the shoulder anchor 18A and each is capable of 
producing the same results as in the prior embodiments. 
In the passive seatbelt system of the present invention as described above, 
since the elastic pieces are fastened such that the rigidity decreases 
towards the center of the belt 10, an extremely confortable entering or 
exiting operation can be provided while still providing an appropriate 
normal belt fastening about the passenger. 
It should be apparent to one skilled in the art that the above described 
embodiments are merely illustrative of but a few of many possible specific 
embodiments which represent the application of the principles of the 
present invention. Numerous and varied other arrangements can be readily 
devised by those skilled in the art without departing from the spirit and 
scope of the invention.