Sealing cutting mechanism

Claim 1

A sealing-cutting mechanism for use in a bag-making machine for manufacturing bags from thermoplastic material of tubular, flexible stock comprising: an elongated knife mounted for vertical reciprocal travel into and out of a mating recess; a sealing bar adapted for vertical reciprocal travel onto a support in proximity to said knife and recess; and an actuating and controlling mechanism operatively connected to said knife and sealing bar comprising a substantially horizontal knife support, a pair of spaced apart vertical rods of which a vertical rod is secured at its upper end to each end of said knife support and slidably mounted in a machine frame for vertical reciprocal travel, a crank-lever pivotally connected to the lowermost end of each vertical rod and keyed onto a common shaft journaled for rotation through the machine frame, whereby said rods are interconnected, and a hydraulic piston-cylinder operatively connected to said crank-lever, whereby said knife can be raised or lowered by actuation of said piston-cylinder; a substantially horizontal sealing bar support, an elongated arm supporting each end of said bar support pivotally mounted at one end on a machine frame, a pair of elongated rods of which an elongated rod is connected at its upper end to each free end of the elongated arm, a second crank-lever pivotally connected to the lowermost end of each elongated rod and keyed onto a common sleeve journaled for rotation through the machine frame, whereby said elongated rods are interconnected, and a cam follower operatively connected to said second crank-lever for transmitting the rotary motion of a cam to a reciprocal vertical motion of the sealing bar.