A method and apparatus for binding the marginal edge of a cover material which has been folded over the periphery of a base material, the method comprising applying varying amounts of heat across the width of the marginal edge where the amount of heat applied at the folding line of the marginal edge of the cover material is less than that applied at portions of the marginal edge removed from the folding line. The apparatus includes means for generating high frequency electrical energy; pressing means for pressing the marginal edge against the base material and applying the electrical energy to the marginal edge to bind it to the base material, the pressing means including an electrically conductive first portion for conducting the high frequency electrical energy and at least one electrically insulative second portion where both the first and second portions contact the marginal edge so that the heat applied across the width of the marginal edge varies. The apparatus also includes a folding frame having a plurality of separable folding sections and means for moving the sections with respect to one another so that when brought together they form a unitary structure. The cover material is disposed on a table and underlaid over one side of the base material so that the marginal edge of the cover material substantially vertically extends above the base material. The apparatus also includes means for lowering the folding frame to the table and includes means for maintaining the folding sections in their separated condition while the frame is being lowered to the table; means for drawing the folding sections together after the frame has been lowered to the table to fold and press the marginal edge over the base material; and means for applying the high frequency electrical energy to the marginal edge to effect the binding thereof to the base material.
展开▼
