Method for stiffening a thin metal plate and board with stiffening edges produduced thereby

摘要

The procedure consists of making a series of parallel folds (11,12,13,14,15) in the edge of the sheet (10), the last of which is formed by a perforated line (70). The free edge of the sheet is tucked inside the recessed edge (20) formed by the first and second folds to form a hollow rigid frame member.