US Patent 7213784 Plastic bobbin and a method of manufacturing such a bobbin

A bobbin (1) of plastic has a cylinder (2) and, formed integrally therewith, circumferential end flanges (3) and is made of a U-shaped channel. Each end flange (3) consists of a plurality of spaced-apart, essentially radial flange elements (4) which are distributed along the circumference of the cylinder (2). In a method of manufacturing such a bobbin, a U-shaped channel is made by injection moulding. The U shaped channel is given such a shape that its side walls consist of a plurality of spaced-apart wall elements which are distributed along the length of the channel. The channel is bent to form the cylinder (2) and its ends are connected with each other in this bent position.