Method of manufacturing lampshades and apparatus for performing the method

摘要

A lampshade is manufactured by forming a sector-shaped blank (10) of heat deformable sheet material, into a hollow truncated cone having upper and lower peripheral edges. The overlapping edges (12) of the blank are fixed together. An apparatus includes an upper former (22) for engagement with the interior surface of the conical blank and a lower support (86), releasably supporting a stiffening ring (90) around its periphery, for example magnetically, so that the upper and lower marginal edge portions of the blank projects respectively beyond the upper former (22) and beyond the stiffening ring (90) supported by the support (86). Heating means (30,58) heat the marginal edge portions and upper (32) and lower (61) die members engage the heated and softened marginal edge portions to fold or roll the deformable sheet material respectively around the edge portion (25) of the upper former and around the stiffening ring (90) supported by the lower support (86) and thereafter hold the formed edge portions in place until the material has cooled. The edge portion of the material deformed around the stiffening ring (90) forms a pocket retaining it. The workpiece is removed from the apparatus after retracting the lower support (86) inwardly from the stiffening ring (90). A mounting bracket (14) is fitted, with its peripheral ring (16) being pushed into the cavity or pocket at the upper edge of the lampshade.