Lately with the development of the housing industry, the secondary housing industry has progressed very rapidly, including manufacture of built-in furniture, kitchen sinks, washing stands as unit equipment.
Kitchen sinks and washing stands are one of the interior fixtures essential for every day life, and a variety of such products directed to the taste of customers are being presented on the market.
Since kitchen sinks and washing stands are fixtures which inevitably involve use of water, a top which supports a basin is provided horizontally as one of the constituent members. As such a top there is usually employed that having a structure obtained by making the surface of a wood derived core material repellent to water and at the same time giving a color so as to serve also as surface decoration or bonding a melamine decorative board having a woodgrain pattern. The kitchen sinks and washing stands are, as described above, fixtures utilizing water indoors, and therefore the used water should not leak into other areas than the sinks and washing stands.
Accordingly, various devices have been imparted to the aforementioned tops fitted with basins in order to prevent leakage of water spilt on the surface of the top through a joint part between a flange part of the basin and the edge of a hole in the top for imbedding the basin. One such example is a product in which a basin flange part is mounted on a top, the joint part thereof with the edge of a hole in the top for imbedding the basin is sealed by fixing a rubber packing or other sealing materials, and the top and the basin flange part are fixed together by screwing from the rear surface of the top. However, those having such a structure suffer from disadvantages that with prolonged use, the rubber packing or other sealing materials are degraded and allow spaces around the edge of the aforementioned imbedding hole to cause water leakage, thereby resulting in swelling and corrosion of the top itself, which then forms gaps between the surface of the top and the basin flange part, finally permitting water spilt on the top to drop onto the floor instead of flowing into the basin, thus making the neighborhood of the sink or washing stand very moist.
As an alternative to those having such structure that the joint part between the basin flange part and the edge of the hole in the top for imbedding a basin is sealed using a rubber packing or other sealing materials, there is a structure in which a hole in the top is made larger than the basin itself, and the top decorative board alone is provided with a hole having the same dimention as the open part of the basin, and the basin flange part is fitted and directly adhered to the hole edge of the decorative board on its rear surface using a synthetic resin. By being of such a structure, since the flange part of the basin is situated lower than the surface of the top, all the water spilt on the surface of the top flows into the basin, thus solving the aforementioned problem of drainage of water spilt on the surface of the top. However, with this structure, the strength of the bonded part between the top decorative board and the basin flange part is weak, and it therefore tends to be damaged during transport and the decorative board is also easily impaired. Moreover, the finish treatment of the synthetic resin used for adhering the joint part between the hole edge of the decorative board and the basin flange part is troublesome and requires a lot of labor and time, and therefore it is not applicable to manufacture of products having a structure suitable for mass production.
As mentioned above, in fabricating tops fitted with basins used in kitchen sinks, washing stands etc., various problems are present from a standpoint of working to prevent water leakage in the joint part between the basin flange part and the hole in the top for imbedding a basin.
The present invention aims to present tops fitted with basins which can provide good water drainage and have a structure permitting their mass production by eliminating problems involved in the structure and fabrication of tops fitted with basins which are constituent members for kitchen sinks and washing stands, as well as a process for their production.