Land vehicles – Wheeled – Attachment
Reexamination Certificate
2000-04-25
2001-07-31
Dickson, Paul N. (Department: 3618)
Land vehicles
Wheeled
Attachment
C280S808000, C297S486000
Reexamination Certificate
active
06267410
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a through anchor by which a webbing pulled out from a take-up device is folded and held in a slidable manner.
2. Description of the Related Art
As illustrated in
FIG. 5
, a three-point type seat belt apparatus
40
is used to safely hold a vehicle occupant in a seat S. One end of a webbing
42
of the seat belt apparatus
40
is taken up by a retractor
44
(take-up device) and another end thereof is fixed via a through anchor
46
to an anchor plate
50
supported at a lower end of a center pillar
48
. Further, a tongue plate
52
provided in the webbing
42
between the anchor plate
50
and the through anchor
46
is engaged with a buckle
54
made upright substantially from the central portion of a vehicle body.
The through anchor
46
is used to fold the webbing
42
so as to fix, to the anchor plate
50
, an end of the webbing
42
of which another end is taken up by the retractor
44
. The through anchor
46
itself is also fixed to the center pillar
48
, for example, by an adjuster mechanism which permits height control.
The through anchor
46
is structured as shown in FIG.
6
. The through anchor
46
is manufactured by molding in which a metal plate
56
having an insertion hole
45
through which the webbing
42
is inserted to pass is set in a metal mold and resin is put into the metal mold. After the molding, a resin molding portion
58
covers a lower half section of the metal plate
56
.
The resin molding portion
58
is formed by putting resin molten at a high temperature into the mold, and thereafter, cooled down. Accordingly, the resin forming portion
58
thermally contracts in the directions indicated by arrow B. In contrast, an insert portion
61
of the metal plate
56
does not typically thermally contract to a significant degree.
As a result, due to a difference in rate of shrinkage between the resin molding portion
58
and the insert portion
61
of the metal plate
56
, residual stress is generated between the resin molding portion
58
and the metal plate
56
. Particularly, a crack may form in a region A in the vicinity of each end of the resin molding portion
58
along a shoulder
57
of the metal plate
56
.
Accordingly, in order to prevent occurrence of a crack, a high-strength material having a low rate of mold shrinkage is conventionally used as the resin molding portion
58
so as to prevent contraction of the resin molding portion
58
caused by residual stress. However, such high-strength materials are expensive.
SUMMARY OF THE INVENTION
In view of the aforementioned, an object of the present invention is to provide a through anchor which allows dispersion of residual stress and can reduce occurrences of cracks in the resin molding portion without using high-strength and/or high-priced materials.
A first aspect of the present invention is a through anchor for a seat belt apparatus for a vehicle, by which webbing pulled out from a retractor is folded and held in a slidable manner, and the through anchor comprises: a metal plate having an insert portion and an exposed portion; a resin molding portion formed by insert molding and covering the insert portion of the metal plate; and a dispersion portion for dispersing residual stress, which is generated between the resin molding portion and the metal plate due to thermal contraction of the resin molding portion caused after insert molding, the dispersion portion being formed in a region in which the residual stress concentrates, wherein the insert portion of the metal plate has an outer peripheral portion and the resin molding portion protrudes beyond the outer peripheral portion by a predetermined amount.
According to the above-described structure, the through anchor is formed by insert molding in which a portion of the metal plate is inserted in a metallic mold and molten resin is injected into the mold, and the metallic mold is subsequently removed.
The resin molding portion is formed in such a manner that resin is molten under high temperature and then cooled. Therefore, after the insert molding, the resin molding portion thermally contracts (shrinks). As a result, residual stress arises due to the differences in shrinkage rate between the resin molding portion and the metal plate, which typically does not thermally contract to a significant degree.
By forming the dispersion portion in the region in which residual stress concentrate, the residual stress is dispersed and problems due to the contraction of the resin molding portion can be alleviated.
In accordance with a second aspect of the present invention, in the through anchor of the first aspect, the dispersion portion includes notch portions formed in vicinities of both ends of a boundary between the resin molding portion and the exposed portion of the metal plate.
According to the above-described structure, the dispersion portion includes notch portions formed in vicinities of opposite ends of the boundary between the resin molding portion and the metal plate. The notch portions expose the metal plate and are each formed in a region in which the residual stress between the resin molding portion and the metal plate tends to concentrate.
When the notch portion is formed in the above-mentioned regions, a portion of the outer periphery of the metal plate, which is conventionally covered with the resin molding portion, is exposed to the outside.
As a result, retardation of contraction of the resin molding portion by the outer periphery of the metal plate is reduced. Accordingly, the risk of crack formation caused due to residual stress from differential shrinkage is significantly reduced.
A third aspect of the present invention is a through anchor for fastening to an interior of a vehicle for supporting seat belt webbing inserted therethrough, the through anchor comprises: a metal fastening portion including a body section having an outer peripheral edge, and a fastening section extending from the body section for fastening to the interior of a vehicle; and a resin molding mounted over the body section, the resin molding having a lip extending past the outer peripheral edge of the body section, with notches defined in the lip and exposing at least a part of the outer peripheral edge of the body section within each notch, wherein a slot is defined through the body section and the resin molding for insertion of seat belt webbing through the slot for supporting the webbing.
REFERENCES:
patent: 5257820 (1993-11-01), Kosugi
patent: 5513880 (1996-05-01), Ohira
patent: 5601311 (1997-02-01), Pfeiffer et al.
patent: 5918903 (1999-07-01), Ito
patent: 6007100 (1999-12-01), Steffens, Jr.
Koketsu Eiji
Ohashi Naoki
Cole Thomas W.
Dickson Paul N.
Kabushiki Kaisha Tokai-Rika-Denki-Seisakusho
Nixon & Peabody LLP
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