Bagmaking apparatuses

Claim 2

Apparatus according to claim 2, wherein said lower Conveyor comprises, interposed between its belts, metal T-section bars having a low coefficient of friction with respect to the flattened tube and having, at the level of the conveying surface of said lower conveyor, a plane face, and wherein the driving roller of the upper conveyor comprises toroidal rings made of a material having a high coefficient of friction with respect to the flattened tube, these rings being disposed such that, when the driving roller brings the rest of the conveying surfaces adjacent to each other, these rings urge the flattened tube against the T-section bars, and exert a supplementary traction on the tube.

Claim 3

Apparatus for making bags from a flattened tube of synthetic material, having, along one of its edges, a longitudinal slit closed along its entire length by a seam formed by mated male and female fastener elements provided in the neighborhood of this slit and carried respectively by the two lips of the slit, said apparatus comprising: a supply for supplying, with an intermittent advance, said flattened tube; a cutting device receiving said flattened tube for effecting, during each stop of the advance of the tube, a transverse cut severing, from said one edge of the tube, the complementary fastener elements and the tube along only a portion of its width; a first welding device for effecting, during each stop of the advance of the tube, a first transverse weld of the walls of the tube, in line with each cut, along the rest of the width of this tube; a separation device for separating from the tube, during each stop of the advance of said tube, the tube element delimited by said cuts and welds; an opening device for opening, by a determined angle, the severed ends of the complementary fastener elements at one side of each tube element; a guiding device for threading a slider onto the thus opened ends of the complementary fastener elements along the longitudinal direction of said seam, and for moving this slider along the fastener considered by a distance greater than the length of the slider; and a second welding device for effecting second transverse welds, in line with said first transverse welds thus joining together the severed portions of each tube element, wherein said opening device comprises two vacuum fingers carried by pivoting arms for engaging the walls of a tube element along the surfaces which are adjacent both to the complementary fastener elements and to a severed side of the tube element, and for then opening these walls from each other, together with the ends of the fastener elements, by said determined angle.

Claim 4

Apparatus according to claim 4, wherein said opening device comprises an element in the form of a wedge presenting said determined angle and adapted to be inserted between the opened walls of the tube element for opening the complementary fastener elements along a length greater than the length of a slider.

Claim 5

Apparatus according to claim 4, wherein said opening device comprises means for directing a jet of air towards the interior of the tube element between the opened walls.

Claim 6

Apparatus for making bags from a flattened tube of synthetic material, having, along one of its edges, a longitudinal slit closed along its entire length by a seam formed by mated male and female fastener elements provided in the neighborhood of this slit and carried respectively by the two lips of the slit, said apparatus comprising: a supply for supplying, with an intermittent advance, said flattened tube; a cutting device receiving said flattened tube for effecting, during each stop of the advance of the tube, a transverse cut severing, from said one edge of the tube, the complementary fastener elements and the tube along only a portion of its width; a first welding device for effecting, during each stop of the advance of the tube, a first transverse weld of the walls of the tube, in line with each cut, along the rest of the width of this tube; a separation device for seParating from the tube, during each stop of the advance of said tube, the tube element delimited by said cuts and welds; an opening device for opening, by a determined angle, the severed ends of the complementary fastener elements at one side of each tube element; a guiding device for threading a slider onto the thus opened ends of the complementary fastener elements along the longitudinal direction of said seam, and for moving this slider along the fastener considered by a distance greater than the length of the slider; and a second welding device for effecting second transverse welds, in line with said first transverse welds, thus joining together the severed portions of each tube element further, comprising a positioning and orientating device for presenting to said opening device each tube element coming from said separation device, so that said opening device can carry out its work.

Claim 7

Apparatus according to claim 7, wherein said device for positioning and orientating the tube elements comprises: a plate on which the separation device successively projects the tube elements, flat and along a determined direction parallel to the fastener elements of the tube element; first advancing means for advancing a tube element along that direction towards a first barrier which borders the plate perpendicularly to said direction and which is removable; second advancing means for advancing a tube element towards a second barrier which borders the plate parallel to said direction; and detection means disposed along said barriers for starting the action of the second advancing means when a tube element abuts against the first barrier by its severed and welded side, these detection means cutting off the action of the second advancing means when this tube element abuts against the second barrier by its side comprising the fastener elements and actuating the opening device which carries out its work on the severed side of the tube element which bears against the first barrier.

Claim 8

Apparatus according to claim 8, wherein said first advancing means comprise nozzles projecting jets of air onto the tube element, and wherein said second advancing means comprise a roller rotating about an axis parallel to said direction and projecting slightly above the plate, between this plate and the second barrier.

Claim 9

Apparatus according to claim 8, wherein said detection means comprise flux emitters and flux receivers respectively disposed on opposite sides of the plane of the plate with a spacing permitting the passage of a tube element.

Claim 10

A mechanism for forming bags with pressure-closable releasably interlocking elements extending along one edge with sliders for the elements from a continuous tube of plastic material having lips along a first longitudinal edge of the tube and an interlocking element carried by each lip comprising; means forming a transverse cut in the tube laterally severing the tube from said longitudinal edge through said elements, means separating the lips and the elements at the cut edge, means moving a slider over the separated elements and positioning the slider at a location spaced inwardly from the cut edge, and means sealing the edges of the layers formed by said cut after said slider is apaced inwardly.

Claim 11

A mechanism in accordance with claim 11 including means forming a second transverse cut from the longitudinal edge opposite the first edge and sealing the edges of the layers at said second cut prior to moving the slider over the lips.