Insertion mechanism, a caulking mechanism and an insertion/caulking device

A caulking mechanism for caulking upper ends of bent portions of flanges in order to fasten an L-shaped corner piece inserted into corner portions of concave outward flanges formed on open edges of a duct having a rectangular cross section comprising:

• a caulking plate movable forward and backward in a horizontal direction relative to the duct;
• a caulking claw which opens toward the duct into an L-shaped form and can contact with upper ends of bent portions of flanges of the duct integrally mounted at one end of the caulking plate;
• the l-shaped opening having an angle which is larger than 90.degree.;
• and
• the other end of the caulking plate being connected to and interlocked with a drive actuator through a drive force transmitting mechanism.

A corner piece insertion/caulking mechanism for inserting an L-shaped corner piece into corner portions of concave outward flanges formed on open edges of a duct having a rectangular cross section and for caulking upper ends of bent portions of the flanges comprising:

• vertically swingable push arms having a pressure member at one end thereof for serving as an insertion mechanism;
• a caulking plate having an L-shaped caulking claw at one end thereof and movable forward and backward relative to the duct for serving as a caulking mechanism;
• an actuator which extends in a first stage and a second stage and retracts for serving as a drive actuator;
• a drive force transmitting mechanism having a cam mechanism for swinging the push arms of the insertion mechanism when the actuator extends in said first stage;
• and
• a mechanism for advancing the caulking plate when the actuator extends in said second stage.