Apparatus for manufacturing lampshades

摘要

A lampshade is manufactured from heat deformable sheet material by forming a blank of the sheet material, in the shape of a sector of an annulus, into a hollow truncated cone having upper and lower peripheral edges. The overlapping edges of the blank are welded or bonded together and the blank supported by an apparatus which engages the interior of the conical blank, which apparatus includes an upper former for engagement with the interior surface of the blank adjacent the upper edge thereof and a lower support, releasably supporting a stiffening ring around its periphery, for example magnetically, so that upper marginal edge portion of the blank projects beyond the upper former and so that the lower marginal edge portion of the blank projects beyond the stiffening ring supported by the lower support. Heating means heat the marginal edge portions and upper and lower die members engage the heated and softened marginal edge portions to fold or roll the deformable sheet material respectively around the edge portion of the upper former around the stiffening ring supported by the lower support and thereafter hold the formed edge portions in place until the material has cooled. The edge portion of the upper former has the form of a rounded beads so that the edge portion of the material deformed therearound has the form of an incompletely closed cavity or pocket. The edge portion of the material deformed around the stiffening ring forms a pocket retaining the stiffening ring. The workpiece is removed from the apparatus after retracting the lower support inwardly from the stiffening ring. A mounting bracket having a peripheral ring is fitted with the peripheral ring being pushed into the cavity or pocket at the upper edge of the blank.