摘要 |
To provide for uniform pressure, under predetermined conditions, of application of closure sealing jaws for a bag making machine, to close thermoplastic tubular foils, a hydraulic pressure element (7;26,28) applies the pressure of a pressure jaw (1) against another (2), with the foil interposed; the hydraulic pressure is sensed by a transducer (11), converted into an electrical signal and compared with a command set signal (22), any error or deviation being fed back in a closed loop to a servo positioning valve (13,15) to thereby set the hydraulic pressure with which the movable jaw (1) is applied against a fixed jaw (2) in accordance with commanded value.
|