Method of manufacturing lampshades and apparatus for performing the method

A method of manufacturing a lampshade from a heat-formable sheet material comprising the steps of:

• providing a former and support assembly including a first former part centred on an axis and having a first annular peripheral bead concentric with said axis and of a first diameter;
• providing a second former part having a second peripheral annular bead at a location spaced from said first bead along said axis and of a substantially greater diameter, wherein said first and second beads face in opposite directions along said axis, and wherein said first former part is hollow and has a peripheral wall extending to an open mouth defined by said first annular bead, said peripheral wall converging conically in the direction towards said axis and away from said second annular bead, and terminating in said first annular bead;
• providing first heating means operable in the region of said first peripheral bead and second heating means operable in the region of said second peripheral bead;
• providing first forming means associated with said first former part;
• providing second forming means associated with said second former part;
• forming a blank of sheet material into the form of a hollow frusto-conical body having first and second peripheral edges providing a narrower and a wider end respectively of said body, and having other edges extending from said first peripheral edge to said second peripheral edge;
• temporarily connecting regions of said other edges of the blank together to hold the blank in shape;
• fitting the blank onto said former and support assembly so that a first marginal edge portion at said narrower end of the frusto-conical body projects beyond said first annular peripheral bead and a second marginal edge portion at said wider end of the frusto-conical body projects beyond said second annular peripheral bead;
• producing relative movement, along said axis, between said former and support assembly and said first heating means to bring said first heating means adjacent said first marginal edge portion;
• heating said first marginal edge portion by said first heating means;
• producing relative axial movement between said former and support assembly and said first forming means to fold the heated and softened first marginal edge portion around said first annular peripheral bead;
• producing relative axial movement between said former and support assembly and said second heating means to bring said second heating means adjacent said second marginal edge portion;
• heating said second marginal edge portion by said second heating means;
• producing relative axial displacement between said second forming means and said assembly to fold the heated and softened second marginal edge portion around said second annular peripheral bead;
• cooling said first and second marginal edge portions;
• displacing said first and second displaceable forming means away from said first and second former parts, respectively;
• breaking said temporary connection of said regions of said other edges of the blank;
• extracting said first and second former parts from the sheet material to leave pockets in the regions formerly occupied by said peripheral beads;
• and
• inserting, into at least one of said pockets, a complementary part of a mounting frame.