Improvements in electrically heated presses for bonding ends of belts

摘要

1,039,898. Seaming non-metallic sheet material. IRA STEPHENS Ltd. June 4, 1965 [June 10, 1964], No. 24014/64. Heading B5K. The ends of a belt B of thermoplastics material to be bonded together are chamfered or overlapped and clamped between metal plates D, D1 and inserted into an electrically heated press A, the plates D, D1 being of greater length than the width of the press A to extend outside the press with the extending portions of the plates heat insulated to prevent heat from the press affecting the belt on each side of the bond. The press A comprises electrically heated pressing members a, a4 mounted, respectively, on a base a1 and on a screw rod a5 or rods loosely mounted in the member a4 and engaging a tapped hole or holes in an arm a3 on a pillar a2, Fig. 3 (not shown), on the base a1. The ends of the belt B are chamfered and laid together with a layer of paste of the material of the belt therebetween, e.g. polyvinyl chloride or nylon paste, and are clamped between the plates D, D1 by screws d spaced at a distance apart greater than the width of the press A. The plates D, D1 each comprise a channel-shaped metal body and have rods d1 of heat insulating material, e.g. asbestos, bolted into the ends thereof with the lower surfaces of the rods aligned with adjacent plate surfaces to prevent heat from the press travelling along the belt beyond the bond. The belt B is clamped to an angle bracket C bolted to the plate D by arms c secured by bolts and wing nuts c1. A thermometer may be housed in a groove in the plate D1. A sheet of nylon coated with polytetrafluoroethylene may be inserted between each side of the belt B and the adjacent plate D, D1. The assembly is positioned in the press A, as shown, and the member a4 is screwed down to apply pressure and bonding effected. The press A may be provided with a watercooled jacket or, after bonding, the plates with the belt clamped therebetween may be transferred to rest on a trough through which cold water is circulated to cool the bond. To join the ends of a two-ply belt, Fig. 4 (not shown), the plies 1, 2 are separated at the ends and equal portions of each ply are removed and the edges of both plies are bevelled. Adhesive is applied to the overlapping ends and they are inserted between the plates D, D1.