The present invention relates to a glass plate washing machine for washing curved glass plates.
Sputtering is one of the methods used for coating the surface of a glass plate with a thin metal film. If stains, traces of guard sheets, yellowed spots, etc., are present on the surface of the glass plate before sputtering, a thin metal film is sputtered on them. The thin metal film sputtered on the stains, guard sheet traces, yellowed spots, etc., is likely to tarnish or deteriorate. The stains, guard sheet traces, yellowed spots, etc., can be removed from the surface of the glass plate by spraying detergent on the surface and washing the surface with a buff grinder, with a buff made of felt, etc..
Various types of glass plate washing machines have been proposed for carrying out the above-mentioned washing process. For example, in Japanese Utility Model Laid-Open Publication Hei 2-1290, one of the inventors of the present invention proposed a glass plate washing machine which comprises buff grinders provided with buffs made of sponge. Japanese Utility Model Laid-Open Publication Sho 63-27249 discloses a glass plate washing machine for washing curved glass plates. The disclosed machine comprises a transferring apparatus for transferring a curved glass plate to a washing position where the curved glass plate is washed. The transferring apparatus has suction cups which adhere to the curved glass plate, first guide rails disposed above and across the washing position, which first guide rails are bent at substantially the same curvature as that of the curved glass plate, second guide rails disposed at right angles to the first guide rails and movably engaged with the first guide rails, which second guide rails are bent at substantially the same curvature as that of the curved glass plate, a movable body movably engaged with the second guide rails, and a polisher mounted on the movable body. In accordance with the glass plate washing machine of this construction, the curved glass plate is held by the suction cups of the transferring apparatus, whereby the curved glass plate is fixed on the transferring apparatus. Then, the curved glass plate is transferred to the washing position by the transferring apparatus, which can move horizontally and vertically. The polisher abuts against the curved glass plate. Detergent is sprayed on the surface of the curved glass plate. The polisher washes the surface of the curved glass plate, while the second guide rails move on the first guide rails and the movable body moves on the second guide rails. After the completion of the washing operation, the polisher separates from the curved glass plate and the curved glass plate is transferred back to the initial position by the transferring apparatus. Then the curved glass plate is detached from the suction cups of the transferring apparatus.
The glass plate washing machine disclosed in Japanese Utility Model Laid-Open Publication Hei 2-1290 is designed for washing flat glass plates and cannot handle curved glass plates. The glass plate washing machine disclosed in Japanese Utility Model Laid-Open Publication Sho 63-27229 is designed for washing curved glass plates and cannot operate efficiently because the process for transferring the curved glass plate to the washing position is complicated and the washing operation is carried out by batch processing. Moreover, if a curved glass plate of different curvature is to be washed, the guide rails have to be changed. In other words, the glass plate washing machine disclosed in Japanese Utility Model Laid-Open Publication Sho 63-27249 cannot promptly adapt itself to changes in the curvature of the curved glass plate.