Winding – tensioning – or guiding – Reeling device – With spring motor
Reexamination Certificate
2000-01-14
2001-10-16
Walsh, Donald P. (Department: 3653)
Winding, tensioning, or guiding
Reeling device
With spring motor
C242S371000, C242S379000, C280S801100, C280S805000, C280S806000, C297S468000, C297S470000, C297S472000, C297S478000
Reexamination Certificate
active
06302346
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to an apparatus for helping to protect a vehicle occupant in the event of a collision. In particular, the present invention relates to an energy management device for seat belt webbing used in a vehicle seat belt system.
2. Description of the Prior Art
Seat belt systems are commonly used to restrain vehicle occupants. A typical seat belt system for restraining a vehicle occupant includes a length of belt webbing extensible about the occupant and having opposite ends anchored to the vehicle. In the event of sudden deceleration such as occurs in a vehicle collision, the occupant tends to move forward relative to the vehicle and is restrained by the belt webbing.
The vehicle occupant can experience a sudden load if the occupant's forward movement is restrained by an inextensible length of belt webbing. To alleviate this sudden load, it is known to provide an energy management device in the seat belt system. When the occupant engages the belt webbing with sufficient force, the energy management device allows the belt webbing to extend slightly. The occupant's movement is restrained at a reduced rate over an increased period of time. This can reduce the maximum load experienced by the vehicle occupant.
One known type of energy management device is described in U.S. Pat. No. Re. 29,147 and includes a length of belt webbing wound on a spool. The spool is mounted on a frame that also includes a plastically deformable torsion bar. When the force on the belt webbing exceeds a predetermined amount, the torsion bar twists, and the spool rotates, enabling the belt webbing to be unwound from the spool.
SUMMARY OF THE INVENTION
The present invention is an energy management device for seat belt webbing for restraining a vehicle occupant. The device includes a base for attachment to the vehicle. The device also includes a plastically deformable torsion bar having a first portion fixed relative to the base and a second portion rotatable relative to the first portion and the base. The torsion bar twists upon rotation of the second portion relative to the first portion. A spool is supported on the base. The spool is fixed for rotation with the second portion of the torsion bar relative to the first portion of the torsion bar. The spool has an axis of rotation and an outer peripheral surface disposed at a distance from the axis of rotation. A flexible member is wound on the outer peripheral surface of the spool. The flexible member has a first end portion connected with the spool and a second end portion extending from the spool for connection with the seat belt webbing of the vehicle. The torsion bar twists and the spool rotates in an unwinding direction upon the application of tensile force from the seat belt webbing to the flexible member in an amount exceeding a predetermined amount, the torsion bar when twisting resisting unwinding of the flexible member from the spool. The distance between the axis of rotation of the spool and the outer peripheral surface of the spool on which the flexible member is wound varies to vary the resistance to unwinding of the flexible member felt by the occupant. The resistance to unwinding varies as a function of the amount of the flexible member that is unwound from the spool.
REFERENCES:
patent: Re. 29147 (1977-03-01), Fiala
patent: 3606378 (1971-09-01), Prostran
patent: 5320385 (1994-06-01), Schmid et al.
patent: 5340046 (1994-08-01), Schroth et al.
patent: 5628470 (1997-05-01), Ray et al.
patent: 5738293 (1998-04-01), Fohl
patent: 5934595 (1999-08-01), Kohlndorfer et al.
Brown Louis R.
Garrell Roger H.
Beauchaine Mark J.
Tarolli, Sundheim, Covell Tummino & Szabo L.L.P.
TRW Vehicle Safety Systems Inc.
Walsh Donald P.
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