Hemming apparatus

A hemming apparatus comprising:

• a lower anvil on which a work having a peripheral part comprising a plurality of superposed sheet materials to be hemmed is placed with the aid of conveying means, said lower anvil being secured to a frame,
• an upper anvil secured to the foremost end of a movable body disposed slidable along a guide member secured to said frame to support said peripheral part of said work from above, said upper anvil being adapted to move from its inoperative position after the work is placed on the lower anvil,
• a presser of which base end is operatively connected to the uppermost end of a piston rod of a first hydraulic cylinder disposed on the frame, said presser being adapted to support the peripheral part of the work from the lower side by displacement of the uppermost end of the piston rod,
• a link arm of which one end is operatively connected to the lowermost end of a piston in a second hydraulic cylinder secured to the frame, a shaft mounted to the middle of said link arm and mounted to the frame, at least one of said link arm and said shaft being turntable relative to the frame,
• a preliminary bending punch operatively connected to the link arm at a position located in the proximity of said one end thereof so as to be slidable relative to the frame to primarily preliminarily bend the peripheral part of the work by displacement of the foremost end of said preliminary bending punch, and
• a main bending punch disposed slidable relative to the frame and operatively connected to the link arm at an opposite end thereof to secondarily bend the peripheral part of the work by displacement of the foremost end of said main bending punch, said preliminary bending punch and said main bending punch being located on said link arm so that an extended and retracted position of said second cylinder results in a sequential bending of said work and the formation of a hem on said work by said punches.