Machine for making, filling and sealing bags

Claim 1

In a machine for making, filling and sealing bags, the latter being obtained from a band of material which is heat-sealable in the usual manner, and filling them with liquid, pulverulent, or granular and other noncoherent products, which comprises an operating structure extending in the vertical direction and including base, a vertical mandrel tube on said base and a profiling collar disposed around said mandrel tube to form a drawing device, means for supporting a reel of heat-sealable material and for conveying said material from top to bottom through the aforesaid annular space between said profiling collar member and said mandrel tube, folding said material in tubular form around and along said vertical mandrel tube with two longitudinal edges superimposed, metering means for a product to be packed disposed above the vertical mandrel tube, advancing means below said profiling collar member and in contact with the said mandrel tube for pulling said band downwards along said vertical mandrel tube, heat-sealing means disposed along said mandrel tube for the heat-sealing of the said superimposed longitudinal edges of the band and below said mandrel tube transversely to the tube of heat-sealable material thus obtained, and means adapted to operate said heat-sealing means in a cyclic phase, the improvement wherein said advancing means and the said heat-sealing means for heat-sealing transversely to the tube of heat-sealable material are associated with support means controlled by continuous motion operating means below the said vertical mandrel tube, the advancing means comprising two sector members having cylindrical surfaces and contrarotating tangentially to a plane containing the axis of descent of the said tube of heat-sealable material, the said continuous motion operating means comprising a cyclic differentiator device, said cyclic differentiator device comprising a first gear having helically inclined teeth meshing with a loose gear having corresponding teeth and of greater axial dimension forming part of said continuous motion operating means, a cam member fixed to said first gear, and a second gear, the said first gear and the said cam member being slidably keyed on the shaft on which the said second gear is keyed, a roller carried loose by fixed support means being engaged in the operating groove of said cam member.