Patent ID: 8307520
Filing Date: 2012-11-13
Classification: B21D,E05D,Y10T

Abstract:
1. A manufacturing method of a shaftless hinge, which is characterized in that it comprises the following steps: (1) punching a flat strip material to form a plurality of blanks, each of said blanks comprises two hinge plates, wherein a first hinge plate is located on a first side of each blank and a second hinge plate is located on a second side of each blank, and then punching the flat strip material to form shaft bush sections with projections on the first hinge plates and thereafter punching the flat strip material to form shaft bush sections without projections on the second hinge plates; (2) curling the shaft bush sections with projections on the first hinge plates first to form shaft bushes whereupon each of the shaft bushes has an extension section formed by the projections and having a substantially cylindrical shape and an outer diameter of d; and then folding the first and the second hinge plates of each blank towards each other so that the substantially cylindrical extension sections of the curled shaft bushes on the first hinge plates are positioned near to the respective shaft bush sections without projections on the second hinge plates; (3) curling the shaft bush sections without projections on the second hinge plates so that shaft bushes are formed; each of the shaft bushes formed by the shaft bush sections without projections has an inner diameter of D and D≧d; and the shaft bushes on the second hinge plates also encloses the respective extension sections of substantially cylindrical shape in Step (2).