JOINING DEVICE OF COLLAR-LIKE SHEET IN WATERPROOF SHEET AND JOINING METHOD THEREFOR

PROBLEM TO BE SOLVED: To provide a device capable of joining a collar-like sheet with a waterproof sheet smoothly and securely without deforming the waterproof sheet even when a joining machine is brought into contact with the waterproof sheet. SOLUTION: This joining device is used to join a collar-like sheet 3 for partitioning a clearance between an outer peripheral face of a segment 2 and an inner peripheral face of a waterproof sheet 4 forward and backward with the cylindrical waterproof sheet 4 provided so as to surround the outer peripheral face of the segment 2. As a device for backing up the joint work of the collar-like sheet 3, a backing lever 6 provided with a backplate which has a curved face like circular arc along the outer peripheral face of the segment 2 and suppresses the deformation of the waterproof sheet 4 to the tail plate 1 side by bringing it into contact with an outer peripheral face of the waterproof sheet 4, a contact part 6c which is continuous with the backplate and comes into contact with an inner peripheral face of a tail plate when the backplate is brought into contact with the outer peripheral face of the waterproof sheet 4, and a handle 6b which is continuous with the contact part 6c and grips the backplate 6a is provided.