Land vehicles – Wheeled – Attachment
Reexamination Certificate
2002-01-17
2004-02-10
English, Peter C. (Department: 3616)
Land vehicles
Wheeled
Attachment
C297S483000, C024S164000, C024S198000
Reexamination Certificate
active
06688647
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a through anchor used for a seat belt device for an automobile.
2. Description of the Related Art
A webbing belt comprising a seat belt device for binding the body of a passenger seated on a seat of an automobile has one end in the longitudinal direction stopped on a winding shaft of a winding device provided on for example, the side of the seat, and the other end fixed on an anchor plate provided in the vicinity of the winding device. Moreover, the middle part in the longitudinal direction of the webbing belt is folded back to the downward direction above the winding device, for example by being placed through an inserting hole formed in a through anchor at the upper end side of a center pillar of the automobile.
The webbing belt is placed through an inserting hole of a tongue plate between the fold back part in the through anchor and the other end so that the webbing belt wound on the winding shaft of the winding device can be taken out by pulling the tongue plate, and the webbing belt can be mounted by interlocking the tongue plate with a buckle device provided on the side opposite to the winding device with respect to the seat.
Moreover, the above-mentioned through anchor comprises a metal mandrel with an original hole for the inserting hole formed. The part of the mandrel other than the part to be fixed on the center pillar of the automobile is molded with a synthetic resin material. Since the molded part is provided also in the original hole inner circumferential part of the inserting hole, the webbing belt is slid with respect to the molded part.
In consideration of taking out the webbing belt smoothly from the winding device, and taking up the webbing belt smoothly on the winding device, it is preferable that the friction between the through anchor and the webbing belt is small. As a means for reducing the friction between the through anchor and the webbing belt, a method of forming a resin piece made of a synthetic resin material such as a polyacetal (POM), and a high molecular weight polyethylene corresponding to the inner circumferential part of the inserting hole of the through anchor to be slid against the webbing belt, and forming a molded part with another synthetic resin material such as a nylon, with the resin piece in the state mounted on the original hole of the mandrel set in a mold, is conceivable.
However, when forming the molded part with a nylon, with respect to the molding temperature of 240° C. at the time of molding, the melting point of the polyacetal is 165 to 175° C., and the melting point of the high molecular weight polyethylene is 136° C., and thus they are lower than the molding temperature. Therefore, since the resin piece made of the polyacetal or the high molecular weight polyethylene is melted or deformed at the time of molding, it has been extremely difficult to mold the molded part with the resin piece shape maintained.
SUMMARY OF THE INVENTION
In consideration of the circumstances, an object of the present invention is to obtain a through anchor capable of maintaining the good molding property and external appearance quality even when using a sliding member made of a synthetic resin material having a melting point lower than that the synthetic resin material providing the molded part, and a method for manufacturing such a through anchor.
According to a first aspect of the present invention, there is provided a method for manufacturing a through anchor comprising a mandrel made of a metal, a molded part made of a synthetic resin material, for covering the mandrel, with an inserting hole for inserting through a webbing belt formed, and a sliding member made of a synthetic resin material having a melting temperature lower than that of the synthetic resin material for forming the molded part, and a friction resistance of the external surface lower than that of the molded part, provided in the molded part corresponding to the sliding part of the inserting hole with respect to the webbing belt, comprising the steps of (a) forming a projecting part projecting from a cavity of a mold for molding the molded part, corresponding to the boundary part of the molded part and the sliding member on the external surface of the molded part and the sliding member, and (b) parting the sliding member and the synthetic resin material for forming the molded part injected in the mold by the projecting part in the vicinity of the external surface of the sliding member at the boundary part.
According to the method for manufacturing a through anchor of the above-mentioned configuration, the mandrel is set in the mold in the state with the sliding member mounted in a part corresponding to the sliding part of the through anchor with respect to the webbing belt in the mandrel. Then, the synthetic resin material is injected into the mold in this state. Thereby, the molded part is provided (hereinafter the synthetic resin material for forming the molded part is referred to as the “molding resin” for the explanation convenience in order to distinguish the synthetic resin material for forming the molded part and the synthetic resin material for forming the sliding member).
Although the molding resin has a melting point higher than that of the synthetic resin material for forming the sliding member, since the projecting part is formed from the cavity of the mold corresponding to the vicinity of the boundary part of the sliding member with respect to the molded part at the external surface in the state with the sliding member and the molded part integrated, the projecting part is provided between the boundary part with respect to the molded part at the external surface of the sliding member and the molten molding resin in the mold so that the boundary part of the molded part at the external surface of the sliding member and the molten molding resin can be parted by the projecting part.
Accordingly, since the boundary part with respect to the molded part at the external surface of the sliding member is not contacted directly with the molten molding resin in the mold, the heat of the molten molding resin is not directly transmitted to the boundary part with respect to the molded part at the external surface of the sliding member. Thereby, at least at the time of molding the molded part, the boundary part with respect to the molded part at the external surface of the sliding member can hardly be melted.
Moreover, since the sliding member has a part with the molten molding resin and the sliding member directly contacted, the heat can be conducted from the synthetic resin material comprising the molded part at the part so as to partially melt the sliding member. However, since the boundary part with respect to the molded part at the external surface of the sliding member is contacted with the projecting part, even if the heat of the molten molding resin is transmitted to the vicinity of the boundary part with respect to the molded part at the external surface of the sliding member, it is discharged to the contacted projecting part, and thus the melting and deformation of the boundary part with respect to the molded part at the external surface of the sliding member can effectively prevented or restrained.
Furthermore, a groove is formed along the boundary part of the sliding member and the molded part at the external surface of the sliding member and the molded part, which are integrated after molding, owing to formation of the projecting part in the mold, with a fixing part of the sliding member and the molded part exposed at the bottom end part of the groove. Although the synthetic resin comprising the sliding member and the molding resin are mixed at the fixing part, since the fixing part is disposed at the bottom or end part of the groove without being exposed at the external surface of the sliding member and the molded part, the fixing part can hardly be seen from the outside so that the external appearance quality of the through anchor can be improved.
It is preferable that the method
English Peter C.
Kabushiki Kaisha Tokai-Rika-Denki-Seisakusho
Nixon & Peabody LLP
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