| 摘要 |
In packaging machines using heat-sealable wrapping material it is important that the heat-sealing mechanism operates in synchronism with the rest of the machine under satisfactory sealing conditions. A control device for sealing bars (14, 15; 40, 41) disposed opposite one another is provided which reciprocates the bars (14, 15; 40, 41) towards and away from one another in phase with the packaging machine operation. The bars (14, 15; 40, 41), or a lever mechanism or mechanical linkage, have arms (16, 17; 54, 54a, 59, 59a) pivotted by integral pins (18, 19; 55, 55a, 56, 56a) with eccentric axes: second pins (19; 56, 56a) are pivotted on the frame and first pins (18; 55, 55a) are rotatable about the axis (80; 70) of the second pins (19; 56, 56a) on movement of arms (16, 17; 55, 54a, 59, 59a) in the closing, sealing phase. At least one pin (18; 56a) has an integral arm (31; 59a) acting on pneumatic means (32; 61) by rotation of first pin (18; 55, 55a) about second pin (19; 56, 56a) to control sealing pressure applied by sealing bars (40, 41) as they are closed. |
