| 摘要 |
A device for welding bags in a heat-sealable plastic material comprising two transverse welding parts (18, 18) carried by respective mobile support elements (20, 20) and means for driving the motion of said support elements, comprising at least, for each of said welding elements (18,18), a rotation drive shaft (26), a train-holder element (28) connected integrally to said drive shaft (26) to rotate together with the latter, a fixed cogged sun wheel (30) integral with the support structure (17), a first cogged planet wheel (32) integral with said element for supporting the welding part (20) and connected freely rotatingly around its own axis to said train-holder element (28) and driven to rotate by the latter, and a second intermediate cogged planet wheel (34) attached to said train-holder element (28) freely rotatingly around its own axis and driven to rotate by the latter. The intermediate planet wheel (34) meshes on said fixed cogged sun wheel (30) and with the first cogged planet wheel (32) of the shaft (20) holding the welding part (18) in such a way that, following rotation of said drive shaft (26), each welding part (18) is driven to perform circular trajectories, always remaining turned in the same direction.
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