Drilling apparatus for flexible sheet made of thick thermoplastic material

Abstract

The invention intends to provide a drilling apparatus capable of forming a beautiful hole with stabilized configuration thereof without special post treatment in a sheet made of flexible thermoplastic material which is a different material from a strict one but a thick material, and ensuring a high productivity. More specifically, this invention provides a drilling apparatus comprising: a table containing a hole having a predetermined diameter at a drilling position thereof for the sheet; a drilling rod made of metal capable of rotating at high speeds while a rotation center line of the drilling rod reciprocating along a center line of the hole between inside of the hole and above the table; and a sheet pressing member disposed above the table and having an insertion hole for the drilling rod, the sheet pressing member being capable of approaching or leaving the surface of the table, wherein the drilling rod has a flat peripheral face composed of at least part of a circular section having no blade and a predetermined clearance is provided between the hole and the diameter of the insertion hole and the diameter of the drilling rod. By pressing the drilling rod rotating at high speeds to the sheet, the sheet material is melted by frictional heat so that a beautiful hole is formed.

Dependencies are inferred from the claim text.