the weld the movement of sheet material through flow line b is reinitiated and a shearing means f which is actuated by signaling means e to sever the ribbon cluster to which a grip member has been welded from the continuous sheet material sheet stock storage rack a may comprise any suitable framework 33 within which thermoplastic sheet stock rolls 34 may be positioned for free rotation thermoplastic sheet stock 32 is thus freely withdrawable from any given sheet stock roll 34 ribbon cluster forming line b comprises a series of rollers some are tensioning rollers like 36 38 40 and 42 to maintain the sheet stock flowing through the line taut and some are pairs of powered rollers like rollers 48 50 58 62 and 72 74 by which sheet stock material is drawn through the ribbon cluster forming line b and properly position for ultrasonic welding to a grip member 9 forming line b contains a ribbon cutting wheel 46 and teflon cutting block 44 which forms the means through which sheet stock 32 is drawn and cut into a plurality of individual ribbon members power is supplied directly to rollers 48 58 and 72 in a manner which is responsive to and coordinated with the operations of ultrasonic welding means d a power transmission means g comprising an electric motor 52 which through drive change 52b drives an air clutch 54 which by belt 54a drives an in out gear box 55 from which through appropriate chain drives 55a power is supplied to rollers 48 58 and 72 powered rollers 48 58 and 72 are preferably of rubber or other resilient composition having a high coefficient of friction rollers 48 and 72 are mounted in frictional engagement with rollers 50.