Winding – tensioning – or guiding – Reeling device – With spring motor
Reexamination Certificate
2000-08-08
2003-02-04
Nguyen, John Q. (Department: 3654)
Winding, tensioning, or guiding
Reeling device
With spring motor
C280S806000, C280S807000
Reexamination Certificate
active
06513747
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is related to providing a pretensioner of a safety belt retractor, and particularly, to a pretensioner integrated with a force transmitting apparatus of a seat belt retractor for reverse-rotating a reel of the retractor on which the safety belt is wound, forcedly, and transmitting the force to tighten the safety belt on an occupant's body upon the occurrence of accident.
2. Discussion of the Background
Until now, much effort has been given on the basic performance of a car such as a comfortable feeling during driving, the speed as well as on a safety apparatuses for protecting passengers. Especially, it is well-known that a safety belt retractor has been significantly developed in its safety performance in respect to passengers, and a pretensioner also has been matched up with the safety belt retractor to enhance the inherent performance of the safety belt retractor. The pretensioner reversely rotates a retractor reel to pull a predetermined length of the safety belt by the power of a power generator using a Pyrotechnic for generating gas or other powers upon the sudden deceleration of the car, for example a crash or an accident. But, it is not certain that the pretensioner already developed would be able to comply with the inherent purpose of restraining the passenger in the seat. The reason is because the technical difficulties exist in adjusting the rewinding length of the safety belt according to the generating power due to the separation of the pretensioner from the generating apparatus.
A typical example of this technique is U.S. Pat. No. 3,043,093 which describes an actuator operated by a gas pressure. The actuator includes a piston which is movably disposed in a cylinder. The cylinder is closed at one end by a bracket and has a gas inlet port through which a gas under pressure may be delivered from any suitable source. A pulley is pivoted in the piston and journaled to cooperate with a cable. The cable has one of its ends from which it passes over a pulley to another pulley fixed to a shaft. On the same shaft as the pulley are a first pulley and a second pulley. The first pulley functions through a cable to operate a load device such as a belt, and the second pulley functions through a web to operate another load device such as means for positioning the shoulders of a pilot. Herein, it is known that the pulley of the shaft and the cylinder including a piston are mounted as the actuator having the same function as the pretensioner. But, the actuator has a possibility to distort the operation of the shaft pulley due to the reverse operation of the first and second pulley against each other, thereby not securing the moving distance of the piston, namely the rewinding length of the belt.
Another example adopting the patent to a vehicle is U.S. Pat. No. 4,423,846 which discloses a retightener for automatic safety belt roll-up devices with a power reservoir, which can be triggered in case of a crash and with an energy transducer which acts upon the belt shaft of the automatic winder after triggering the power reservoir, causing the automatic winder to perform a rotary retightening motion. For example, the retightener is provided with an automatic safety belt winder. A belt shaft is extended beyond a rewind spring cover by a shaft extension. The face of the shaft extension has sawtooth-shaped axial teeth which can be coupled to correspond to sawtooth-shaped and axial counter teeth of pulling means pulley. Serving the mounting of the pulling means pulley is a trunnion which is molded on a cup-shaped cover and permanently joined to the automatic winder housing or screwed by screws to the cover. The pulling means pulley is axially movable on the trunnion. Four cams are molded to the cover in the form of curved protruding in corresponding recesses with slanted, wedge-shaped strike surfaces in the pulling means pulley. A shear pin is fixed in the cover and projects into a hole in the pulling means pulley, fixing the latter in the inoperative, inactivated position. A cable or pulling means is connected to the pulling means pulley. Upon tension of the cable, the shear pin is sheared off, and at the same time the pulling means pulley is moved axial towards the axial teeth via cams, so that a coupling connection of the counter teeth and the axial teeth is established. This couples the belt shaft to the pulling means pulley, to the cable and to a preceding power reservoir drive. Consequently, the belt is tightened by turning the belt shaft again.
But, the retightener requires larger care in withdrawing a predetermined length of a belt because the cable length to be withdrawn is varied dependent upon the position of the pin. Also, because the retightener requires an auxiliary mechanism to be mounted for the operation of the pulling means pulley along with a power reservoir, the mounting of the safety belt retractor provided with the retightener is limited in respect of having to secure a space in the vehicle.
To overcome these disadvantages, a seat belt retractor with a pretensioner is disclosed in U.S. Pat. No. 5,489,072. As shown in
FIG. 1
, the retractor includes a spring casing
2
mounted on one side thereof and a spring
1
of a clock spring type retained in the spring casing
2
, in which one end of the spring
1
is fixed to the fixing groove formed on the inner surface of the spring casing
2
, and other end positioned in the center of the spring
1
is fixed to a fixing arbor
8
of the spring casing
2
. The spring casing
2
is mounted on the side of a pretensioner housing
3
. A reel
4
on which a safety belt is wound is rotatably mounted on an U-shaped bracket
6
by means of a shaft coupling member such as a bearing (not shown).
A pretensioner is mounted between the bracket
6
and the spring casing
2
and includes the housing
3
and a pyrotechnic force generator
21
. The housing
3
is provided with a clutch drum
18
, including three internal actuated indentations of an approximate triangle in the form of a pulley and three rollers
15
. The housing
3
is provided with two frangible pins
12
integrally moulded on its interior and three integrally moulded frangible pegs
14
rotatably carrying each of roller
15
.
Upon mounting of the pretensioner, each of the rollers
15
is seated on the rounded corner of the indentations
16
in the clutch drum
18
while being rotatably mounted on the pegs
14
. The clutch drum
18
is mounted in the inner portion of the housing
3
with apertures
13
being coupled with the pins
12
, respectively. Also, on the periphery of the clutch drum
18
there is formed a groove corresponding to a cable
19
with both side surfaces
17
. A center shaft
10
of the reel
4
is passed through the indentation
16
of the clutch drum
18
and a hole of the housing
3
and then fixed to the fixing arbor
8
. The cable
19
is turned over the groove of the clutch drum several times. One end of the cable
19
wound is fixed to the periphery of the clutch drum
18
and other end is connected to the pyrotechnic force generator
21
. The pyrotechnic force generator
21
serves to pull the cable
19
connected to a piston (not shown) upward, when the vehicle is abruptly decelerated and an igniter (not shown) is detonated. At that time, the cable
19
rotates the clutch drum
18
, and the frangible pins
12
are sheared. Then, the pegs
14
are sheared to enable the rollers
15
to be trapped in the locking position between the cam surfaces of the indentations
16
and the outer surface of the center shaft
10
, thereby rotating the reel
4
by a predetermined number.
But, the pretensioner cannot have a predetermined withdrawal length of the cable, because the cable length is changeable according to the position of the cable fixing end on the periphery of the clutch drum, and the distance of play for coupling the rollers with the center shaft exists.
Furthermore, U.S. Patent '846 or '072 is subject to break the pins upon reverse-rotating of the clutch drum or the p
Jin Sung-woo
Kim Seung-Man
Lee Jong-hoon
Delphi Automotive Systems Sungwoo Corporation
Fish & Richardson P.C.
Nguyen John Q.
LandOfFree
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