Patent ID: 7181945

Claim:
An apparatus for forming a first semi-manufacture pulley having an inner hub and an outer hub forming portion, comprising: a first rotating device for rotating a plate working piece along with a first spindle, the first rotating device including the first spindle rotatably installed at a center thereof, a first centering pin, that is elevated in the first spindle, for guiding an opening of the plate working piece to settle the plate working piece at a predetermined position, a supporting block around an upper end of the first spindle, and a supporting ring around the supporting block for supporting an edge of the plate working piece placed on an upper surface of the supporting block; a first supporting device having a first supporting pin rotatably positioned at an upper portion of the first rotating device arranged to ascend and descend along the first rotating device, the first supporting device including a first upper mandrel ring located at a lower end of the first supporting pin to extend through the opening of the plate working piece for pressing an upper end of the first centering pin, while pressing an edge of the opening of the plate working piece with the step portion formed on the lower end of the outer peripheral surface thereof in order to fix the plate working piece; a first pressing means having a first pressing roller for pressing an upper surface of the plate working piece inwardly so as to form the inner hub of the first semi-manufactured pulley around the first upper mandrel ring; a second rotating device including a second spindle rotatably positioned at a center thereof, a second lower mandrel ring at an upper end of the second spindle and having an annular projection on an upper surface thereof to be inserted in a region defined by the inner and outer hubs of the first semi-manufactured pulley, and a second ejecting pin positioned in the second lower mandrel ring to ascend and descend along the second lower mandrel ring, for settling and releasing the first semi-manufactured pulley, the second rotating device being arranged for causing the first semi-manufactured pulley to rotate with the second spindle; a second supporting device rotatably positioned at an upper portion of the second rotating device to ascend and descend along the second rotating device and having a second upper mandrel ring at a lower end thereof far fixing the first semi-manufactured pulley by pressing an inner region of the outer hub of the first semi-manufactured pulley; and a second and third pressing means of the apparatus respectively having a second pressing roller and a third pressing roller for sequentially pressing an edge of the first semi-manufactured pulley inwardly to form a convex bead portion.