| 摘要 |
<p>1507085 Adjusting package length BAKER PERKINS HOLDINGS Ltd 1 Nov 1976 [12 Nov 1975] 46763/75 Heading B8C [Also in Divisions B5 and F2] A wrapping machine comprises a tube former for forming a web into a tube, an adjustable speed web-feeding mechanism, a conveyer for feeding articles into the former, crimping dies to seal the tube transversely between the articles, adjustable modulating means for matching the speed of the dies and the speed of advance of the tube during formation of the transverse seals, and an adjustable mechanism for driving the dies so that they will form, at will, seals at every revolution of a drive-shaft (30), or every 2nd, 3rd, ... nth revolution, the adjustable mechanisms for driving the web and dies together allowing a wide range of package lengths to be produced. The modulating means may be a cyclically variable drive as in Specification 1,420,471 and be used to drive the dies or the web-feeding means which comprise rollers which longitudinally seal the tube. The dies may be rotary dies. The adjustable mechanism comprises a clutch 32 which drives the dies through one revolution for each or for each nth revolution of the clutch driving shaft (30). This shaft carries a plate 34 carrying a pivoted latch 35 which is normally biased by a spring 35A into engagement with a flange 36 on the output shaft of the clutch. However, when a trip plate 37 engages the latch as shown the latch moves out of driving engagement with the flange 36. The plate is held in the trip plate engaging position by a lever 45 until a ratchet 40 depresses the lever. The ratchet is moved forward by one tooth for each revolution of the driving shaft 30 by a pawl 39 mounted on an eccentric 42 of a cam-shaft 38 driven from the shaft 30. Movement of the trip plate 37 to its release position also raises the pawl 39 allowing the ratchet 40 to be moved back by a spring 43 to a starting point determined by an adjustable stop 44.</p> |
