| 摘要 |
<p>A horizontal packaging machine for wrapping and sealing articles with flexible films comprises, a servo control system for maintaining synchronism between the finwheel drive (14), the in-feed conveyor (3) and the cut-off knife assembly (9) so that proper registration of the graphic art work on the packaged article is achieved. The finwheels (8,15) are driven by D.C. motor (13) whose armature windings are connected to the ouput of a servo amplifier (10). A master tachometer (20) driven by the horizontal wrapper's drive motor (see 6) provides a voltage which is directly proportional to the angular velocity of that drive motor. The output from the master tachometer (20) is passed through a calibrating network and into a first input (19) of the servo amplifier circuit (10). A second tachometer (16) is coupled to the finwheel shaft and produces a feedback signal proportional to the angular velocity of the finwheels (15). The feedback signal is applied to the second input (18) of the servo amplifier (10) and functions to control the D.C. current driving the finwheel drive motor (13). The system also includes a digital logic network (80,81) which senses a reference mark (70a) on the film from which the package is formed along with the rate at which the end-seal cutting blade is rotating (see 87 to 89) to produce a supplemental or vernier control signal for adjustment of the rotational speed of the finwheel (15).</p> |
