Winding – tensioning – or guiding – Reeling device – With spring motor
Reexamination Certificate
2000-04-04
2001-11-27
Jillions, John M. (Department: 3653)
Winding, tensioning, or guiding
Reeling device
With spring motor
C242S382000
Reexamination Certificate
active
06322018
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a seatbelt retractor, and specifically to a lockbar for a seatbelt retractor.
BACKGROUND OF THE INVENTION
A seatbelt generally comprises belt webbing that passes over a vehicle occupant's torso to restrain forward movement in a crash. The webbing is wound on a spool that is mounted in the retractor for rotation about its longitudinal axis to wind in or pay out webbing. The spool is biased in a winding in direction by a spiral spring. A sensor detects a crash, for example by detecting acceleration or deceleration above a predetermined level. The crash sensor activates a locking mechanism to lock the spool against rotation and prevent further pay out of webbing thus restraining the occupant against forward motion.
The spool is locked by engagement of teeth on a ratchet wheel on the edge of the spool with a locking pawl. Often two locking pawls are used mounted at opposite ends of a bar extending the length of the spool so as to lock both ends simultaneously. Such a lockbar is traditionally made in one piece of a single type of material, for example as a metal die casting.
However, die cast parts are inherently rather weak and the traditional U-shaped lockbar is complex to manufacture.
The present invention provides an improved lockbar for a seatbelt retractor and an improved method of manufacturing or assembling a lockbar.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a lockbar for a seatbelt retractor comprising at least three parts separately manufactured and subsequently connected together.
According to a preferred embodiment of the present invention, the lockbar comprises an elongate joining member and two end pieces joined to the joining member at opposite ends therefore, the end pieces being made of a higher strength material than the joining member. In one embodiment the end pieces are of a generally L-shaped form.
The joining member may be made by extrusion and may be tubular or may be formed as a hollow member, for example, of prismatic form (i.e., with a triangular cross-section). It is preferably designed to have relatively high torsional and axial stiffness but can be made of relatively low strength material such as aluminum or glass-filled plastic.
The end pieces may be produced as forgings, die casting or plastic injection moldings or by other suitable methods. They can be produced from different materials and to different designs to suit the specification of the seatbelt retractor. For example, forged aluminum or steel end pieces are envisaged. These materials have a higher mechanical strength and a better metallurgical microstructure than die cast parts.
Hence a single basic seatbelt retractor design can be employed for a variety of strength requirements by selecting appropriate end pieces and an appropriate joining member.
The end pieces, being either generally flat or L-shaped are easier to manufacture than the traditional one piece U-shaped lockbar.
The end pieces may be attached to the joining member in a variety of ways to suit the strength requirements and the materials from which the parts are made.
For example, the joining member may be hollow along its whole length or at its end to accommodate projections on the end pieces in the form of bars or pins. Alternatively, extending pins on the ends of the joining member may fit into holes in the end pieces. The joints may be made stronger by pressing, spot welding, riveting, over molding, over casting and/or by using adhesive.
The end pieces also generally comprise pin formations for guidance purposes that interact with features in the retractor mechanism to move the end pieces into locking positions. These may be formed as separate pieces and inserted or otherwise attached. They may be formed by pressing out, semi-shearing, over molding, over casting, cold forging, friction welding or other suitable methods.
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Blackadder David
Bowman Paul
Harte Joseph Patrick
Mitchinson Nigel
Smithson Alan George
Breed Automotive Technology Inc.
Drayer Lonnie
Jillions John M.
Rieger Jarett
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