1. Field of the Invention
The present invention relates to a method and an apparatus for producing a cap having a very small thickness to be fitted around a neck portion of a drink bottle such as a wine bottle or the like. Further, the present invention relates to a cap having a very small thickness to be fitted around a neck portion of a drink bottle such as a wine bottle or the like wherein the cap is produced using aluminum or aluminum alloy as a blank.
2. Description of the Prior Art
To protect a neck portion of a drink bottle such as a wine bottle or the like from damage or injury, and moreover, maintain the neck portion in a clean state, a cap made of a metallic material is normally fitted around the neck portion of the bottle. Generally, the metallic cap is produced using a sheet of lead having both surfaces covered with tin foil. To plastically deform the sheet of lead to a contour corresponding to a cap product, a so-called spinning process has been heretofore employed wherein the sheet of lead is spun by manually actuating a specially designed tool while the sheet is rotated.
When a metallic cap is produced by employing the foregoing spinning process, the thickness of a blank can not usually be reduced to 0.2 mm or less. Thus, with the conventional spinning process, there arises a drawback that material cost is increased because of the comparatively heavy thickness and the employment of an expensive metallic material like tin. Another drawback is that the surface of the cap produced by the spinning process can not exhibit a brilliant appearance. In addition, careless disposal after removal of the lead cap from the neck portion of a drink bottle may cause pollution. For this reason, it is anticipated that employment of lead for the cap will be prohibited in the future.
Given the circumstances described above, attention has recently turned to aluminum as a metallic material to be fitted around the neck portion of a bottle, because aluminum is a cheap metallic material, does not cause any public pollution after disposal and, moreover, can be reused by melting it.
With the conventional process, however, a cap having a very small thickness can be produced using a soft metallic material like lead but can not be produced when a comparatively hard metallic material like aluminum is employed as a raw material.