the hand - operated tensioning and welding apparatus for thermoplastic bands includes a clearance control lever pivotable in a frame , a combined control lever pivotably supported on the clearance control lever and being coupled via an overrunning coupling to a tensioning roller also supported for rotation on the clearance control lever and cooperating with a tensioning bed which is formed on the upper surface of a movable clamping member . a crank arm is supported for rotation about the axis of the combined control lever and cooperates with a delayed action coupling to drive via a linkage a movable heating element for heating the overlapping portions of the thermoplastic band , and further to drive a press ram for compressing the heated band portions and to a cutting device for severing the welded band from a supply roll .