Land vehicles – Wheeled – Attachment
Reexamination Certificate
2000-01-18
2002-07-16
Swann, J. J. (Department: 3611)
Land vehicles
Wheeled
Attachment
C280S801100
Reexamination Certificate
active
06419271
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a seatbelt device comprising a buckle pretensioner for fastening a seatbelt to a passenger by retracting the buckle upon situations such as a sudden deceleration of a vehicle.
2. Description of the Related Art
Conventionally, as means for fastening a seatbelt to a passenger upon situations such as a sudden deceleration of a vehicle, other than a belt tension device arranged on the retractor side of the seatbelt, used was a buckle pretensioner for retracting toward the lower part of the vehicle body a buckle to be engaged with.a tongue plate mounted on the midway position of the seatbelt.
This conventional buckle pretensioner, for example, retracts the buckle by retracting toward the lower part of the vehicle body a connective member such as a steel plate, rod, wire, webbing, or tape provided for fixing the buckle to the vehicle body or seat, etc. The buckle pretensioner thereby exhibits its function as a securing device by securing a passenger to the seat with such operation.
Here, if the buckle pretensioner is structured to be capable of retracting the buckle toward the lower part of the vehicle body in a straight line, the structure thereof could be made with an extremely simple mechanism. Generally speaking, however, a buckle pretensioner is usually installed in the space between the seat and center console. Thus, in consideration of the fact that the installation space is small, and in order to secure the comfortableness and safety of rear-seat passengers and to improve the outward appearance of the vehicle interior, the buckle pretensioner is devised such that the connective member is folded back via a pulley, for example, to change the retractive direction thereof.
In order to change the retractive direction of a connective member, a certain degree of freedom (adjustability) is required regarding the “folding” of such connective member. Thus, adopted as the material for the connective member used in existing products is, for the most part, a wire member or tape member including a webbing.
A connective member is often retained with a retractor (specifically, for example, a piston activated by the pressure of the combustion gas inside the cylinder) which retracts the buckle and comprises a structure of retracting the buckle by being pulled by such piston. Accordingly, the connective member retracts the buckle upon being exposed to the combustion gas inside the cylinder.
Furthermore, conventional buckle pretensioners are disclosed, for example, in Japanese Utility Model Laid-Open Publication No. Sho 50-83718, Japanese Utility Model Laid-Open Publication No. Hei 6-35061, Japanese Patent Laid-Open Publication No. Sho 49-61822, and so on.
The buckle pretensioners described in Japanese Utility Model Laid-Open Publication No. Sho 50-83718 and Japanese Utility Model Laid-Open Publication No. Hei 6-35061 have both the connective member and pulley—or only the connective member—arranged inside the cylinder, and comprise the structure of changing the retractive direction by converting the direction of the connective member with the pulley.
The buckle pretensioner described in Japanese Patent Laid-Open Publication No. Sho 49-61822 comprises a direct-acting structure using a rod as the connective member.
Moreover, the conventional buckle pretensioner shown in
FIG. 24
comprises a structure wherein a gas generator
319
for filling combustion gas into the combustion gas chamber
320
and a driving member
310
for retracting the buckle
311
are provided at separate locations. Specifically, the component for mounting the gas generator
319
is composed of a die-cast product, a cylinder
315
is mounted thereon and, for example, a piston
316
, a hook member
317
for preventing reverse operations, and a wire rope
313
are partially housed in such cylinder
315
.
In addition, reference numerals
322
,
325
,
327
, and
335
denote an O-ring, cap, ball, and base, respectively. Reference numeral
314
is a pulley for changing the direction of the wire rope
313
.
With conventional buckle pretensioners, it is usually necessary to hermetically seal the cylinder for efficiently converting the combustion gas pressure into retractive power to retract the buckle. Nevertheless, a method widely adopted is to provide a through hole to the cylinder for retracting the connective member or piston rod and, thus, there is a possibility that the combustion gas will leak therefrom. Although measures such as using sealing members to achieve airtightness are being taken, it is not possible to completely prevent gas leakage, and the actual condition is that the retractive efficiency is lowered thereby.
In the buckle pretensioner described in Utility Model Laid-Open Publication No. Sho 49-61822, there is particular concern that the combustion gas generated upon the retraction of the buckle will blow out, in no small quantities, from the rear seat side. Moreover, depending on the setting of the retractive stroke of the piston, there is a possibility that the buckle pretensioner may interfere with the vehicle floor.
Conventional connective members changing the retractive direction such as those described in Japanese Utility Model Laid-Open Publication No. Sho 50-83718 and Japanese Utility Model Laid-Open Publication No. Hei 6-35061 are structured from a wire member or tape member, and are exposed to combustion gas. Therefore, upon endeavoring to improve the durability of such connective members, there is a problem in that the costs therefor and the weight thereof will increase.
Moreover, as the buckle pretensioner shown in
FIG. 24
comprises a structure wherein the driving mechanism
310
for retracting the buckle
311
and the gas generator
319
are arranged at separate locations, the shape of the component for mounting the gas generator becomes complex. It is therefore necessary to manufacture such component with the die-cast method, and this will lead to high production costs.
SUMMARY OF THE INVENTION
The present invention aims at resolving the aforementioned conventional problems, and an object thereof is to provide a seatbelt device comprising a buckle pretensioner capable of preventing a connective member from being subject to high temperature/pressure and efficiently converting combustion gas pressure, which provides pressure for retracting the buckle, into retractive power.
Another object of the present invention is to provide a seatbelt device comprising a buckle pretensioner realizing the simplification in the shape of structural components and the reduction of manufacturing costs.
In order to achieve the aforementioned objects, the present invention provides a seatbelt device comprising a buckle pretensioner, wherein the buckle pretensioner includes: a retractor for retracting the buckle pursuant to the combustion gas pressure of powder; and a connective member for connecting the retractor and the buckle; and wherein the connective member is arranged in a position such that it is not exposed to the combustion gas.
The buckle pretensioner of the seatbelt device comprising this structure is capable of preventing the connective member from being subject to high temperature/pressure as the connective member is arranged in a position such that it is not exposed to the combustion gas. Moreover, as the connective member is not inserted into the combustion gas chamber (a cylinder for example) to which the combustion gas is filled, this gas chamber may be made airtight. It is therefore possible to efficiently convert the combustion gas pressure into retractive power of the buckle.
The buckle pretensioner of the seatbelt device of the present invention, for example, may have a multistage structure of converting the combustion gas pressure into extrusive power and then converting this extrusive power into retractive power of the buckle.
More specifically, the buckle pretensioner of the seatbelt device according to the present invention may be of a structure wherein the retractor includes: a cylinder; a gas generator for
Wada Yoshihiko
Yamada Hiroshi
Yamamoto Kazuo
Crowell & Moring LLP
NSK Ltd.
Shriver J. Allen
Swann J. J.
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