WRAPPING MACHINE FOR SINGLE OR GROUPED AND/OR STACKED PRODUCTS, IN PACKS OF THERMOPLASTIC MATERIAL OBTAINED FROM FILM UNWOUND FROM A REEL AND RELATED OPERATING METHOD
There is described a machine for packaging products in tubular wrappings of thermoplastic material obtained from continuous film unwound from a reel, equipped with a double transverse heat-sealing and intermediate cutting assembly that, with a horizontal translation movement, accompanies the pack that the assembly is closing the trailing end of to be unloaded while it is simultaneously closing the leading end of the tubular wrapper of the future pack that the heat-sealing and cutting assembly, also due to the presence thereon of pressers and counter-pressers, extracts from a tube-forming and longitudinal heat-sealing mandrel and that, by the same assembly, is separated from the pack upstream with a transverse cut. At the end of its active movement, the transverse heat-sealing and cutting assembly opens and with a horizontal movement in the opposite direction to and at a higher speed than the preceding one returns to the cycle start position, upstream of a new pack already filled and ready to be heat sealed at the trailing end and accompanied to be unloaded, repeating the cycle described. The transverse heat-sealing and cutting assembly is aided by a conveyor that supports and advances the packs being formed and those finished and separated, and that is equipped with a gap with variable geometry, which opens during the active horizontal movement of the same assembly and closes during the reverse horizontal movement of the same assembly.
The present application claims priority to PCT International Application No. PCT/IB2016/054007 filed on Jul. 4, 2016, which application claims priority to Italian Patent Application No. 102015000032736 (UB2015A002063) filed on Jul. 10, 2015, the entirety of the disclosures of which are expressly incorporated herein by reference.
STATEMENT RE: FEDERALLY SPONSORED RESEARCH/DEVELOPMENTNot Applicable
BACKGROUNDThe invention relates to a machine for wrapping single or grouped and/or stacked products, particularly paper or nonwoven products, for sanitary or other uses, in packs of thermoplastic material obtained from a film unwound from a reel and concerns the operating method of this machine.
It should be noted that the terms “upstream” and “downstream” used hereinafter relate to the direction of feed of the packs.
As state of the art closest to the invention, filed in the international class B65B63/02, the U.S. Pat. No. 4,679,379, filed in 1983 by the same inventor of the present patent application, is cited. This document describes a packaging machine equipped with a horizontal hollow mandrel, of the type in the shape of a sailor neck tie, to one end of which there is fed a continuous sheet or film of thermoplastic material, unwound from a reel, which proceeding towards the opposite end of the mandrel, is formed in a tube with overlapping and heat-sealing of its longitudinal edges and that, upon delivery from the same mandrel, is closed transversely by a transverse static assembly that, on command, carries out a prior gusseting operation on the opposite sides of the same tubular wrapping and that on the gusseted portion of the same tube carries outs two transverse heat seals and an intermediate cut, to close the trailing end of the pack filled and formed in the previous cycle, to close the leading end of the future pack to be formed and to separate the completed pack from the one being formed. Upstream of the tube-forming mandrel of the packaging film there is provided a loading station of the products to be packaged, for example toilet rolls, absorbent paper for kitchen or other uses, packs of napkins or hand towels, also in nonwoven, where these products are grouped together and/or stacked to form a bundle that is preferably subjected to slight pressure in transverse direction and that after this step has a cross section of a shape and width slightly less than the internal cross section of said hollow mandrel on the outside of which said tubular wrapping slides, gusseted and closed at the leading end. In correct phase, a pusher is activated to eject the bundle from said loading station, slide it along said hollow mandrel and, at the exit thereof, push it against the closed leading end of the tubular wrapping, causing this wrapping to advance and, while it exits from the hollow mandrel, become engaged by the bundle, which due to the previous slight transverse compression to which it was subjected in said loading station and due to its elastic memory, expands slightly and closely engages the portion of tubular package ejected from the mandrel and which with this is supported by conveyor means below. The pusher ends its active movement downstream of the mandrel and slightly downstream of the transverse heat-sealing and cutting assembly, which is in open position, after which the same pusher reverses its movement and returns to the cycle start position, to free the loading station and allow repetition of a new operating cycle. In sequence, the lateral gusseting means of the portion of tubular wrapping positioned between the trailing end of the bagged bundle and the discharge mouth of the tube-forming mandrel are activated, followed by activation of the transverse heat-sealing and cutting assembly, which carries out closing of the trailing end of the filled pack, which closes the leading end of the pack being formed and still to be filled, after which said assembly opens slightly to release the heat seals and allow action thereon of optional blower cooling means positioned on the same assembly, which in sequence opens fully to allow repetition of a new operating cycle, while the pack produced is moved away by the conveyor that supports it. When a new operating cycle is repeated, said transverse heat-sealing and cutting assembly must be fully open to allow the tubular pack to advance pushed by the product inserted therein by the pusher that carries out its active operating movement. To prevent the heat seal of the leading end of the tubular pack being filled from yielding under the thrust of the product in the bagging step and therefore prevent the pack from tearing and bursting, also due to the air that is compressed by the product when it advances in the tubular pack closed longitudinally and at the leading end, in the current state of the art it is possible to act as follows:
a) to ensure effective cooling of the heat seal of the leading end of the tubular pack, the idle times between one operating cycle and the next are extended;
b) the product is inserted into the tubular pack being formed and closed at the leading end, at slow speed, to allow the air that remains trapped in the front part of the pack to escape by passing between product and pack. Just as the previous solution, this solution unavoidably limits the operating speed and consequently the productivity of prior art packaging machines.
BRIEF SUMMARYThe invention intends to overcome these and other limits of the prior art, to produce reliable packaging machines with high hourly production rates, with the idea of a solution according to the appended claim 1) and to the subsequent dependent claims, for which the transverse heat-sealing and cutting assembly is provided with pressers upstream and downstream of the heat-sealing means, so as to firmly clamp the film before, during and after the step of carrying out the transverse heat seals. In combination with said pressers, the same transverse heat-sealing and cutting assembly is movable in the pack forming direction, first closed and moving away from said tube-forming mandrel and then open and in the opposite direction, to return to the cycle start position for repetition of a subsequent operating cycle. The tubular pack can now advance along the tube-forming mandrel drawn by the new double transverse heat-sealing and cutting assembly with pressers, as a result of which it is possible:
1. to produce strong and efficient heat seals, with the times required to ensure proper implementation thereof, as these heat seals are carried out in the forming and filling step of each subsequent tubular pack, while the transverse heat-sealing and cutting assembly is closed and moves away from the mandrel;
2. while the new tubular pack advances drawn by the transverse heat-sealing and cutting assembly with pressers, which has heat sealed the leading end of the new pack, has closed the trailing end of the pack of the previous cycle and is accompanying this latter to be unloaded, the same new pack can be filled rapidly by said pusher, as the presser downstream of this transverse heat-sealing and cutting assembly mechanically isolates the transverse heat seal of the leading end carried out on the new pack, so that this transverse heat seal is not stressed by insertion of the product into the new tubular pack and by thrust of the air trapped in the same pack and positioned in front of the product, also because in this step it is possible for the pusher to insert the product into the new pack with a relative speed that allows slow and progressive backward discharge of the air that is compressed upstream of the product;
3. during its movement away from the tube-forming mandrel, the transverse heat-sealing and cutting assembly has all the time required to carry out its main transverse heat-sealing and cutting operations and, in the last part of the same movement, it also has time to open the heat sealers slightly and allow action of the means for natural or forced cooling of the transverse heat seals carried out, while the film upstream and downstream is held by the pressers at all times to prevent even minimum stress on the same transverse heat seals;
4. the return movement to the cycle start position of the transverse heat-sealing and cutting assembly, after it has been opened, overlaps the return movement at the same speed of the pusher for bagging the product and, after this return step, a pack filled and ready for closing of the trailing end is already positioned downstream of the transverse heat-sealing and cutting assembly.
It is evident how with the new solution according to the invention, packaging machines that are more reliable and faster than those of the prior art can be produced.
Further characteristics of the invention, and the advantages deriving therefrom, will be more apparent from the following description of a preferred embodiment thereof, illustrated purely by way of non limiting example in the figures of the eight accompanying drawings, wherein:
From
In
Downstream of the mandrel 1, at a short distance from the outlet 201 thereof, there is provided the innovative assembly 13 that carries out the double transverse heat seal and the intermediate cut on the pack and that, according to the invention, after closing on the vertical plane, is operated first with a horizontal movement away from the same mandrel 1, to accompany the pack in the transverse heat-sealing and cutting step and then, after opening on the vertical plane, is translated horizontally in the opposite direction to the preceding one, to return to the initial starting position illustrated with a continuous line in
In order to perform said horizontal translation movement B, as also illustrated in the details of
The assembly 13 comprises two elements 113′ and 113″ parallel to and opposite each other, positioned on a common ideal vertical plane, transverse to the longitudinal direction of the ideal plane 5 of advance of the packs, the lower 113″ of which is positioned under this plane 5 at the start of each cycle, while the upper element 113′ is raised and at a distance from the plane 5 that allows the packs cyclically exiting from the mandrel 1 to pass below without interference. In the active operating step, the elements 113′, 113″ are moved towards each other with a self-centring movement on the common ideal vertical plane, so as to meet approximately at half the height of the packs to be closed. To allow the machine to produce packs of different height, the position in height of the support and guide means of said elements 113′ and 113″ can be adjusted simultaneously, without adjusting the related distance at rest. For this purpose, as illustrated in
Fixed to the inner sides of the aforesaid vertical slides 23 with supports 29 and 30 that respectively support them by the lower end and by an intermediate area, are vertical guide rods 31, with a round section, sliding on which, with the interposition of recirculating ball bearings, are sleeves 32 and 33, the lower of which 32 slides between said supports 29, 30 and supports the end of the lower transverse heat-sealing and cutting element 113″, while the upper sleeves 33 slide above the supports 30 of the respective rods 31 and support the ends of the upper transverse heat-sealing and cutting element 113′. In
From
From the details of
In
From
With reference to
The assembly 13 must be able to carry out simultaneously, on the portion of tubular pack on which it is pressed transversely, the parallel heat seals ST2 for the pack already filled and to be closed at the trailing end, the parallel heat seal ST1 for the following pack still to be filled with product, the intermediate cut that produces the edges B2, B1 and the mutual separation of the packs and to carry out punching to form the opening G acting as handle.
From
The lower element 113″ of the assembly 13 as shown in
Moving the elements 113′ and 113″ of the transverse heat-sealing and cutting assembly 13 towards each other in parallel, as shown in
If the machine is to produce packs C2 as shown in
In
In the subsequent step illustrated in
While the assembly 13 moves to the right, as illustrated in
From
In sequence, as illustrated in
As illustrated in
It is understood that the description refers to a preferred embodiment of the invention, to which numerous variants and modifications can be made, all without departing from the guiding principle of the invention, as described, illustrated and as claimed below.
In the claims, the references indicated in brackets are purely indicative and do not limit the scope of protection of these claims.
Claims
1. A wrapping machine for wrapping individual or grouped and/or stacked products, in packs of thermoplastic material of the type comprising a hollow horizontal mandrel to the loading end of which there is fed a continuous film of thermoplastic material, unwound from a reel, which proceeding towards the unloading end of this mandrel, is formed in a tube with overlapping and mutual heat-sealing of its longitudinal edges by heat-sealing means and which exits from the same mandrel in the form of a tubular wrapping, which is closed transversely by an assembly positioned downstream of the same mandrel and which, on the portion of the tubular wrapping previously gusseted by folders, carries out two transverse heat seals and an intermediate cut, filled and formed in the previous cycle, to close the leading end of the following pack and to separate the completed pack from the one being formed, and which comprises upstream of said mandrel and aligned longitudinally therewith, a loading station of the products to be packaged, grouped and/or stacked and compressed in transverse direction and which upstream of this station comprises aligned longitudinally, a pusher that, on command, transfers the product or products from the loading station into the tubular pack produced by said mandrel, passing through this latter for the whole of its length and beyond, characterised in that the parallel and opposed elements that form said assembly for carrying out the double transverse heat seal and the intermediate cut, are equipped upstream with respective pressers and counter-pressers to firmly clamp in transverse direction the portion of gusseted wrapping on which this assembly, on command, is closed, the same assembly being mounted on a main carriage with horizontal movement and operated by motion means to be able in correct phase to be moved away from the tube-forming mandrel to follow the completed pack during heat sealing of the trailing end and to extract from the mandrel a new portion of tubular wrapping into which in correct phase said pusher inserts a product to form said subsequent pack, there being provided means such that said main carriage is returned rapidly to the initial position moved towards the mandrel, to be arranged downstream of the new pack already filled and to be closed at the trailing end, a motorized conveyor being provided to support the packs being formed downstream of said mandrel and the upper branch of this conveyor being guided on parallel rollers supported rotatingly by said main carriage and being guided in a zigzag path on further rollers supported by a secondary carriage sliding horizontally on command on the same main carriage, all so as to form at said double transverse heat-sealing and intermediate cutting assembly a gap inside which the lower element of said assembly is normally housed and this gap being opened by the movement in one direction of said secondary carriage, to allow freedom of action of this lower element and the same gap, when engaged by said lower element, being closed by the movement of said secondary carriage in the opposite direction, so that said conveyor correctly supports the packs being formed during the return movement of said main carriage.
2. The wrapping machine according to claim 14, wherein the main carriage that carries said double transverse heat-sealing and cutting assembly, is equipped laterally with slides that slide on pairs of rectilinear and horizontal guides fixed longitudinally to the side panels of the portion of base plate of the same machine and these side panels also support, parallel to said pairs of guides, toothed belts closed in a loop and guided on respective end pulleys, a pair of which is interconnected by a transverse shaft in turn connected to a motion assembly with electric motor that rotates in two directions and of the type with electronic speed and phase control, the two side panels of the main carriage being connected to a branch of said two toothed belts, by means of clamps, to receive therefrom the necessary rectilinear reciprocating movement with the necessary acceleration and deceleration ramps.
3. The wrapping machine according to claim 1, wherein the support means of the two parallel and opposed elements that form said double transverse heat-sealing and cutting assembly, are mounted on respective vertical slides positioned inside the side panels of the main carriage that support said slides with guide means, each slide being equipped with a protruding intermediate appendage, with a lead screw that cooperates with a vertical screw, in turn connected to a three-way bevel gearbox, the vertical way of which acts on said screw, while one of the horizontal ways connects the same screw of a slide to that of the slide of the opposite side, which will be served by a two-way bevel gearbox, while the third horizontal way of said gearbox is connected to a motion assembly, with electric motor that rotates in two directions and preferably of the type with electronic speed and phase control, to allow the automatic or semi-automatic adjustment of the position in height of the transverse heat-sealing and cutting assembly when the height of the packs to be produced varies.
4. The wrapping machine according to claim 34, wherein fixed to the inner sides of said vertical slides with supports that respectively support them by the lower end and by an intermediate area, are vertical guide rods, with a round section, sliding on which, with the interposition of recirculating ball bearings, are sleeves if the lower of which slides between said supports and supports the end of the lower transverse heat-sealing and cutting element, while the upper sleeves slide above the upper supports of the respective rods and support the ends of the upper transverse heat-sealing and cutting element, the sleeves of each said rod being fixed by means of respective clamps to the opposite branches of toothed belts guided on a pulley supported adjustably by the upper end of each rod and on a toothed pulley supported by the lower end of each said vertical slide and the same lower pulleys are connected to each other by a synchronizer shaft, in turn connected to a motion assembly with electric motor that rotates in two directions and preferably of the type with electronic speed and phase control, which transmits to the opposed elements of the transverse heat-sealing and cutting assembly the movements for total or partial closing or total or partial opening, with the necessary acceleration and deceleration ramps.
5. The wrapping machine according to claim 1, wherein the pressers positioned upstream and downstream of the upper element of the double transverse heat-sealing and cutting assembly, are stressed in downward extension by respective counter springs so that when they are at rest, the lower edges with rounded profile of the same pressers are suitably spaced from each other by the lower operating surface of the same upper element while the lower element of the same assembly comprises with arrangement on a common horizontal ideal plane, counter means opposite said upper pressers which, similarly to these counter means are produced or machined so as to have a high coefficient of friction in contact with the tubular wrapping of film that forms the packs and that exits from said tube-forming mandrel, all so that, also in combination with the action of said counter springs said wrapping of film is able to be firmly clamped between these pressers and the respective counter means both when said elements are thrust against each other to carry out the two transverse heat seals and the intermediate cut for which they are responsible, and when these elements are close to each other but with the transverse heat-sealing and intermediate cutting means raised by the respective counter means, to free and cool the heat sealed and cut portions of wrapping.
6. The wrapping machine according to claim 2, wherein said secondary carriage that supports the zigzag guide rollers of the upper branch of the conveyor, is equipped laterally with horizontal and longitudinal guides sliding on slides fixed on the top of a cross member, in turn fixed with its ends to the side panels of the main carriage, this cross member supporting rotatingly and in a cantilever fashion, a pair of screws parallel to each other and to said guides and these screws cooperate with respective lead screws, integral with appendages of the secondary carriage, and these screws being operated by a motion assembly flanged to said cross member and operated by an electric motor that rotates in two directions and optionally also of the type with electronic phase control.
7. A method for wrapping single or grouped and/or stacked products, in packs of thermoplastic material obtained from film unwound from a reel, with a machine according to claim 1, with a transverse heat-sealing and cutting assembly equipped with pressers and counter pressers upstream and downstream of the transverse heat-sealing and cutting means, to be able to firmly clamp the tubular pack of film during the step of carrying out the transverse heat seals and in which the same transverse heat-sealing and cutting assembly is movable in the pack forming direction, first closed and moving away from the tube-forming mandrel and then open and in the opposite direction, to return to the cycle start position for repetition of a subsequent operating cycle, all so that advance of the tubular wrapping along the tube-forming mandrel can take place drawn by the same double transverse heat-sealing and cutting assembly with pressers, characterised in that with this assembly it is possible to carry out in the forming and filling step of each subsequent tubular pack, while the transverse heat-sealing and cutting assembly is closed and moves away from the mandrel and also characterised in that the return movement to the cycle start position of the transverse heat-sealing and cutting assembly, after it has been opened, overlaps the return movement at the same speed of the pusher for bagging the product and, after this return step, a pack filled and ready for closing of the trailing end is already positioned downstream of the transverse heat-sealing and cutting assembly.
8. The method according to claim 7, characterised in that while the new tubular pack advances and is drawn by the transverse heat-sealing and cutting assembly with pressers, which heat seals the leading end of this new pack, closes the trailing end of the pack of the previous cycle and is accompanying this latter to be unloaded, the same new pack can be filled rapidly by the designated pusher, as the presser downstream of this transverse heat-sealing and cutting assembly, mechanically isolates the transverse heat seal of the leading end carried out on the new pack, so that this transverse heat seal is not stressed by insertion of the product into the new tubular pack and by thrust of the air trapped in the same new pack and positioned in front of the product, also as in this step it is possible for the pusher to insert the product into the new pack with a relative speed that allows slow and progressive backward discharge of the air that is compressed upstream of the same product and against the leading end of the new pack.
9. The method according to claim 7, wherein during the active movement away from the tube-forming mandrel, the double transverse heat-sealing and cutting assembly, is given all the time required to carry out its main heat sealing and cutting operations and, in the last part of the same active movement, to open the heat sealers and the cutting means slightly to free the transverse heat seals and allow action of the means for natural or forced cooling of these heat seals, while the wrapping of the packs upstream and downstream is held at all times by the pressers, which prevent even minimum stress on said transverse heat seals.
10. The method according to claim 7, characterised in that in the initial step of its operating cycle, the double transverse heat-sealing and cutting assembly can be closed only partially on the gusseted tubular wrapping and in this partially closed condition can be moved slowly away from the tube-forming mandrel so as to move towards the pack downstream and compress it longitudinally, after which the same assembly is fully closed and increases its speed of movement to carry out the double transverse heat sealing and intermediate cutting steps for which it is responsible.
Type: Application
Filed: Jul 4, 2016
Publication Date: Mar 7, 2019
Inventors: Stefano Cassoli (Casalecchio Di Reno, Province of Bologna), Marco Cassoli (Casalecchio Di Reno, Province of Bologna), Paolo Cassoli (Casalecchio Di Reno, Province of Bologna)
Application Number: 15/743,041