METHOD OF FORMING A SHEET METAL CUP WITHOUT A MANDREL

摘要

The invention comprises a method of forming a sheet metal cup without using a mandrel. A cup shaped blank (10) is first produced having a relief (11) on a rim (12) or outer circumference. The blank (10) is clamped in the spinning machine. The relief (11) controls and facilitates the bending process, creating a uniform curve at a predetermined bending point. During the rolling process, a forming roller (20) is engaged with rim (12), and is moved progressively parallel with an axis of rotation (A-A). As the forming roller (20) moves, the rim (12) is progressively bent from an orientation normal to an axis of rotation to a position parallel to the axis of rotation. The fully formed rim (12) can then be punched to accommodate a bearing or shaft. This allows a small radius pulley to be formed without use of a mandrel.