Patent ID: 6684608
Filing Date: 2004-02-03
Classification: B68G

Abstract:
A method of manufacturing a spring unit for use in mattresses, spring upholstered furniture and the like, in which said spring unit comprises a continuous coil spring contained within a sleeve of strong, yet flexible material wherein the method comprises the steps of:i) providing a folding attachment device having oppositely inclined spaced planar walls which converge from a feed end to an outlet end, said inclined walls being interconnected at one pair of edges by a support plate; said device further having a guide bar spaced from said support plate extends between said walls at said feed end; ii) feeding said material through a gap between said support plate and said guide bar to ensure that said material does not buckle or crease as it is drawn through said folding attachment device; iii) simultaneously drawing said flexible material and said coil spring through said folding attachment device from said feed end to said outlet end with said spaced walls acting to fold said material over said coil spring and to apply a substantially uniform compressive force to said coil spring; and iv) joining overlapping edges of said flexible material together at a joining station to form said sleeve and complete said spring unit as said material and said coil spring are drawn through said outlet end.