Certain vehicle seats are provided with openings in the seat back for the purpose of passing a seat belt, an ornamental effect or for ventilation. An annular plate member may be fitted to each opening for maintain the shape of the opening. See JPH10-181524A and JP2006-43000A, for instance. In the prior art disclosed in JPH10-181524A, the opening is designed for passing a seat belt, and a belt guide also serving as a member for retaining the shape of the opening is attached to the peripheral part of the opening. This belt guide is attached to the skin member via a frame member attached to the peripheral part of the skin member surrounding the opening of the skin member. The frame member is provided with projections that fit into corresponding openings formed in the peripheral part of the skin member in order to ensure a secure attachment between the skin member and the frame member.
In the prior art disclosure in JP2006-43000A, ventilation openings are passed through a head rest of a seat in the fore and aft direction, and a garnish serving as a member for retaining the shape of the opening is fitted into an opening of the skin member. The garnish is provided with projections that fit into corresponding openings formed in the peripheral part of the skin member in order to ensure a secure attachment between the skin member and the garnish.
The member for retaining the shape of the opening of the skin member is typically made of plastic material which is harder than the pad and the skin member. Therefore, when a tension is applied to the pad or the skin member, the pad or the skin member may deform to such an extent that a gap may be created between the shape retaining member and the skin member. Such a gap is not desirable not only because of an esthetic view point but also because of the risk of catching a foreign object therein. Also, because the skin member is engaged by the projections projecting from the shape retaining member, an excessive tension applied to the skin member may tear up from the holes thereof receiving the projections therein.