| 摘要 |
A method is disclosed for bending a band (4) of sheet metal to give the band (4) a helical shape, and an apparatus (10) is also disclosed for actuating the method. The method comprises steps of: supplying a band (4) of sheet metal shaped as an open ring; abutting a first portion (3) of the band (4) with a first abutting surface (2); exerting a pressure on a radial second portion (19) of the band (4), such that a part of the band (4) comprised between the first portion (3) and the radial second portion (19) assumes a shape alike to a portion of helix. The step of abutting the first portion (3) of the band (4) comprises blocking the band (4). The pressure exerted on the radial second portion (19) is obtained: by contacting the radial second portion (19) of the band (4) by means of a second abutting surface (6), and thereafter rotating the second abutting surface (6) by a first angle and in a predetermined first direction (D1 ) such that the part of the band (4) comprised between the first portion (3) and the radial second portion (19) assumes a shape alike to a portion of helix. |
