WO1997042077A1 - Improvements to self-contained sacking machines - Google Patents

Abstract

One of the improvements consists in setting up between the sack forming station (1) and the sack filling station (3) an intermediary station (2) at a distance from the sack filling station (3) substantially smaller than the distance existing between the filling station and the closing station (4) so that during the transfer of the sacks (8) by the carriage (9) said sacks arrive at the sack filling station (3) within a time substantially shorter than the time required for the transportation to the other stations, thus allowing a much longer time for the filling phase. Another improvement consists in providing a welding mechanism in order to reinforce the extremities of the sack after each has been filled and closed. Another improvement consists in providing the sacking machine with a sack conforming unit intended to break up the continuous tubular band from which said sacks are obtained and to close them by welding the lower extremity of each of the sacks, all of which being carried out in optimum conditions so that the sacks are capable of withstanding the filling phase coming immediately after.

Description

 IMPROVEMENTS INTRODUCED IN AUTONOMOUS SALTING MACHINES

D E S C R I P C I Ó N

OBJECT OF THE INVENTION

The present invention is in the field of autonomous bagging machines, capable of forming, filling and closing the bags, and more specifically the invention focuses on a series of improvements with which the performance of this type is enhanced. of machines, while improving their functionality.

Specifically, one of the improvements consists in placing an intermediate or waiting station between the bag forming station and the filling or packaging station, which requires that the transfer of the bag from that intermediate station to the filling station be considerably less than the time used in the transfer between any of the other stations of the machine.

Another improvement focuses on a welding mechanism with which considerable reinforcement is achieved at the two ends of the bag, in order to provide greater mechanical resistance at the bases of the bag, that is, in the weakest areas since It deals with closed areas by welding.

Another improvement consists of a studied and advantageous shaping group of the bags, being favored the operation of the machine and the final result in the bagging operation itself. The type of machines in which the improvements of the invention are applicable are those for the packing of bulk products, both granular and powdery, such as cattle feed, fertilizers, plastic pellets for industrial processes, glazes for ceramics, etc. .

BACKGROUND OF THE INVENTION

Various types of bagging machines are known which use as a raw material a tubular body, of a heat-weldable plastic nature, of indefinite length, supplied in coil, with folds or side bellows, in which basically three operating sets are established, a bag-forming assembly , which conveniently fragments the continuous coil while establishing the closure of the lower extremity of each unit or bag, a filling mechanism that supplies each bag with the corresponding dose of the product in question, and a closing mechanism that, after said filling , conveniently close the bag in conditions of shipment or storage thereof.

In this regard, it is worth mentioning the German patent DE-4,314,711, which describes a device for filling and closing bags, previously formed from a continuous coil or band, in which each bag or unit is picked up by the area near its mouth, by means of tweezers that turn the bag 90 °, that open it and place it under the filling mechanism, after which and by another 90 ° turn, the bag reaches a closed station, located on top of a conveyor belt, where the bag is deposited, after closing, in a perfectly vertical position, to prevent a possible and abrupt lateral tilting of the bag, in its impact on the conveyor belt, causes the opening of the same, through the newly made and still hot welding.

US 4,510,736 shows another machine of this type, in which a first carrier stage of the bottom of the bag stands out, in which drive nozzles, a filling stage and a bag closing stage participate, in accordance with the basic general scheme referred to above. Also in this case the bags must be placed completely vertical so that the closing weld does not suffer and can be damaged by the product pressure itself.

In German patent 2,614,270 a bag filling machine appears, which has been specially designed for the specific case in which such bags are considerably wide, also having the purpose of maintaining their verticality. In this case there are also the basic steps mentioned above for filling the bag or bag and closing it, with cooling of the weld, and with the particularity that under the filling stage there is a mechanical button that compacts the contents of the bag .

US Patent 5,448,879 shows another solution in terms of a bag forming machine.

Finally, in the European patent EP 0 516 979, a process for manufacturing, filling and closing bags is described, in which consequently the three basic functional stages that constitute the common denominator of the vast majority of machines of this type are given , which has been mentioned before, but the implementation of the procedure according to this patent implies the participation of extremely complex mechanisms that have a very negative impact on both the cost of the machine and its subsequent maintenance.

On the other hand, the type of bags referred to above, being obtained from a continuous tubular band with bellows or lateral folds, presents a problem of closing both for its lower extremity and for its upper extremity, consisting in that the corresponding welds transversal, which in an intermediate and majority sector of the bag exclusively affect the two walls of the bag, abruptly affect, at its ends, the four partitions that originate the folds or bellows of such side walls, so that on each line of said welding, three sections are established, one intermediate and two ends, the latter two times thicker than the intermediate section, which means weakening points for such welding, in correspondence with the junction points between said three sectors. In addition, these side bellows of the bag, intended to open during filling thereof, cannot do so in their extreme zones, since they are prevented by transverse closing welds, defining in such extreme areas permanent folds to which it would be desirable not to access the material to be bagged, for a better general configuration of the bag after its filling and definitive closure.

In order to solve this problem, it is known to fix the two halves of each bellows to the corresponding side walls of the bag, in the extreme areas of the sack, by means of welds that affect small triangular areas. However, the solutions adopted so far to achieve such welds, either are structurally very complex, or have a negative impact on the productivity of the machine, increasing the time corresponding to each operating cycle of the same.

In any case, the aforementioned machines are provided with dragging means for continuous tubular band, welding means to establish the closure of the bottom of each of the bags, and cutting means to make the following bags independent, offering the aforementioned machines different solutions in this regard. , which all have, as a common denominator, an extraordinary structural complexity that has a negative impact, both on the manufacturing costs of these machines, and on subsequent maintenance costs. In addition, in this type of bagging machines the filling of the bags is carried out immediately after the formation of the bags, so that sometimes the welding constitutive of the bottom closure of the bag, because it has not cooled sufficiently, is not able to receive the load of product that it carries out in the bag.

DESCRIPTION OF THE INVENTION

The improvements that the invention proposes solve in a fully satisfactory manner the above-mentioned problem, allowing high productive rates, with a simple, and consequently economic, structure for bagging machines.

In accordance with the above, to achieve high production, of the order of 1,200 bags / hour, this means that the machine has 3 seconds for each of its different operational phases.

In the bag forming station and considering a welding time of 1.5 seconds, perfectly reasonable, plus an additional 1.2 seconds for measuring the length of the bag, the time required is 2.7 seconds, which obviously remains for Below the available time.

The same is not the case with the bag filling station since, as is known, the use of bags with side folds or bellows, which should not be opened during handling, is imposed every day, since otherwise it would be problematic recover them again, keeping the bag well presented, to which we must also add the growing demand for corner welds in the corners of the bag, which obliges to keep the aforementioned folds during the whole process of manufacturing, filling and closing the bag. This means a significant reduction in the section available as "inlet" of the product in the bag, which means a longer filling time, in addition to the fact that, due to savings in packaging material, correct presentation of the bag and good stability of this in the pallets, a good settlement of the product in the sack is required, for which the use of a knocking or compactor mechanism that in turn also "consumes" extra time is planned.

It follows from the foregoing that, in order to maximize the quality of the packaging, obviously at the expense of the time supplied to this operation, the dead time involved in transferring the bag from the bag must be reduced to the maximum. conformation station to the filling station.

Well, according to one of the improvements of the invention this is achieved by using an intermediate or waiting station, very close to the packaging station, so that each bag, instead of passing directly from the station of conformation to the packing station, it passes first to this intermediate station, whereby the transfer from said intermediate station to the filling station requires considerably less time.

According to another of the characteristics of the invention in this intermediate station a pre-opening maneuver of the bag is carried out, with the collaboration of a clamp provided with suction cups, so that the possible initial opening difficulty offered by the bag Due to the residual effects of the cutting maneuver, it is canceled in this intermediate station, the opening of the sack being carried out, in the subsequent filling station, practically instantaneously, collaborating with such maneuver, together with the suction cup set corresponding to said filling station, a transverse displacement in the direction of approach, of the clamps that hold the bag.

According to another of the improvements that are recommended, the car for transferring the bags between the different constituent stations of the machine adopts a U-shaped configuration of lateral branches oriented towards the exit of the machine, so that it offers a totally diaphanous space in the whole area of transfer of the bags, since the lateral fixing clamps of the latter only emerge towards the inside of the lateral branches of the carriage in those moments when they close over the sacks.

According to another of the improvements of the invention, in said carriage three sets of clamps are established of which the two extreme sets are rigidly connected to said carriage, while the intermediate game is mounted through guides and with a movement of floating character, specifically through two lateral pneumatic cylinders, which act as mere elastic elements with which a stop cooperates with the machine bed, conveniently facing the filling station, so that in front of the carriage path, fixed, which determines a fixed path also for the extreme jaws, between the forming station and the intermediate station, on the one hand, and between the filling station and the closing station, on the other, the route between the intermediate station and the filling station is much shorter so that the filling operation can be started earlier, that is to say with a greater use of the available space corresponding to each cycle.

According to another of the characteristics of the invention, a compacting element is established under the filling station and associated with the support frame of the evacuation conveyor belt, which strikes on the base of the bag improving the filling conditions thereof.

According to another of the characteristics of the invention, it is envisioned that an approach sensor for said clamp is established in the sacks closing station, specifically in the mobile arm of the welding clamp, which allows detecting the absence of sack, the existence of a fold in the sack mouth, the existence of product residues in said mouth that damage the closure, or any other type of anomaly that can be detected by an abnormal dimension in the thickness of the sack mouth.

According to another aspect of the invention, the machine in which the improvements are applicable also incorporates a welding mechanism for bag reinforcement, which is precisely intended to ensure that triangular welding at the ends of the bellows of each bag is carried out quickly. , simple and effective.

For this, and more specifically, the welding mechanism that is recommended, according to another of the improvements of the invention, is intended to be established between the feeding station and the bagging station of the machine, so that the welding of reinforcement of said sacks are carried out prior to their shaping, specifically on the continuous band, before fragmentation thereof. At the exit of this corner welding mechanism there is a cooling device and centering of the continuous band.

Specifically, the welding mechanism is structured by means of two heads capable of regulating their mutual distancing, in order to adapt it to different bag widths, each of these heads having a guide plate as a guide in the soldier destined to stay in the fold or corresponding bellows of the continuous tubular band, penetrating to the bottom of said bellows, in order to conveniently independent all sectors thereof, while on both sides of this guide sheet the clamps of the welding jaw, which after each unitary displacement of the continuous tubular band are closed against the intermediate guide plate causing simultaneous welding of the marginal areas of the lower end of a sack and the upper end of the immediately following sack, specifically by a unique trapezoidal weld that, in the subsequent bag-forming station, will be fragmented by its midline, one of its two halves becoming part of a bag and the other of the next bag, as previously stated. On both sides of this piece or sheet metal guide that has to withstand the high temperatures of the warming of the heads, there are also similar guide plates between which the bag passes through in its formation, sheets that have holes made through which they pass through the welding pieces, thereby achieving that when the welding parts are removed, once the welding operation of the corners has been carried out, the material of the bag is retained without being dragged by gluing on the welding parts.

The closing of these welding clamps, in each welding phase proper, can be carried out by any appropriate conventional means, such as pneumatic pistons, for which purpose the arms of each clamp will be mounted with the possibility of transverse displacement on the corresponding head , for synchronized approach or distance to the intermediate guide plate.

The machine also includes as another one of the improvements some means or forming group that solves a series of problems originating in conventional machines of this type referred to in the background section of the invention. To do this and more specifically, the forming group that is recommended is structured from a pair of tangent rollers, one drag and another presser, the first one driven by a motor reducer and through an encoder that allows controlling the rotational movement thereof will be determined to determine a continuous dimensionally accurate tubular band drag according to the size of the bag to be obtained, while the press roller is pivotally mounted on end arms and is manually detachable from the drag roller with the collaboration of an eccentric can be operated by means of a lever.

The support chassis of these rollers, drag and presser, constitutes in parallel the support means for a pair of tilting reinforcements, each of them supporting the corresponding welding and cutting mechanisms, both reinforcement being synchronized and contrasted, by means of respective connecting rods, through an eccentric driven in turn by a pneumatic cylinder, so that the drive in a certain direction of the piston of said cylinder causes the approximation of the welding and cutting jaws, while the displacement in the opposite direction causes their separation.

As a complement to the structure described and in order to ensure optimum safety in the determining welding of the bottom of each bag, it is provided that under the aforementioned cutting and welding mechanism, at the lower level of the machine, a deflector plate is established that directs the bottom and closed edge of the sack towards a pair of blowing nozzles, elongated in correspondence with the width of the sack, a fixed, although of adjustable positioning, and the other swingarm to approach the first, by means of the actuation of a pneumatic cylinder, so that once the welding corresponding to the lower extremity of a sack has been located at the level of the blowing nozzles, these are they approach each other by exerting their cooling action on both sides of the bag and achieving a fast consistency of their welding, by cooling it.

Since these types of machines are capable of forming and filling sacks of different dimensions, it is provided that the length of the aforementioned blow nozzles is adequate to the maximum width foreseen for said sacks, and that at the same time the blower mechanism in its set is adjustable in height, in order to positionally adjust said blow nozzles to the height of each type of bag. In this sense, the support of the aforementioned blow nozzles is mounted on the chassis of the machine through vertical guides, and has a spindle or similar transmission means for lifting / lowering it, operated from a steering wheel, through a mail or any other suitable means of transmission, so that by manually acting on said flywheel the working level for the blower nozzles can be established, suitable, as previously mentioned, at any bag size.

DESCRIPTION OF THE DRAWINGS

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, a set of drawings is attached as an integral part thereof, with an illustrative character tive and not limiting, the following has been represented:

Figure 1 shows a schematic representation in side elevation of an autonomous bagging machine made in accordance with the improvements object of the present invention, which appears in a retraction limit situation for the car.

Figure 2.- Shows a schematic plan representation of the assembly represented in the previous figure.

Figure 3.- Shows a representation similar to that of Figure 1, in the initial phase of advancement for the bag transfer car.

Figure 4.- Shows a plan view of the assembly represented in the previous figure.

Figure 5.- Shows, again according to a representation similar to that of figure 1, the same set of said figure in the limit of advance for the transfer carriage.

Figure 6.- Shows a plan view of the assembly represented in the previous figure.

Figure 7 shows a representation similar to that of Figure 1 in the retraction phase for the carriage, that is to say in the phase of return to the position of said Figure 1 to complete the operating cycle of the machine.

Figure 8.- Shows a plan view of the assembly represented in the previous figure. Figure 9.- Shows a schematic representation in cross section of the machine, at the level of the filling station.

Figures 10 and 11.- They show two details in perspective of the machine, which help to better understand its general structure.

Figure 12 shows a schematic representation in side elevation of the same autonomous bagging machine provided with the welding mechanism for the reinforcement of bags subject to another of the improvements of the present invention.

Figure 13.- Shows a partial and plan schematic representation of the continuous tubular band constituting the raw material for forming the bags, just as said tubular band leaves the welding mechanism represented in the previous figure.

Figure 14.- Shows a front elevation detail of said welding mechanism.

Figure 15.- Shows a plan view of it.

Figure 16.- Shows a perspective view of the same welding mechanism, conveniently coupled to a bagging machine, represented only partially.

Figure 17.- Shows a schematic representation in side elevation of a bag forming group for bagging machines, made in accordance with Another improvement of the invention.

Figure 18.- Shows a plan view of the assembly represented in the previous figure.

Figure 19.- Shows a detail in perspective of the same set represented in the two previous figures.

Figure 20.- Shows a side elevational view of the cooler that collaborates with the actual conformator represented in the three previous figures.

Figure 21.- Shows a front elevation and sectional view of the assembly of the previous figure.

Figure 22.- Shows, finally, a perspective view of the assembly represented in the two previous figures.

PREFERRED EMBODIMENT OF THE INVENTION

In view of these figures it can be seen how an autonomous packaging machine made in accordance with the improvements of the invention is structured based on a bag forming station (1), an intermediate or waiting station (2), a station filling (3) and a closing station (4).

In the bag forming station (1) and as is conventional, the continuous tubular band (5) is fragmented at regular intervals, depending on the expected height for the bags, and welded to lower said bags, by means of a pair of welding and cutting heads (6), under which it is placed a first pair of support clamps (7) for the bag (8) already formed, pair of pliers (7) immovably mounted on a carriage (9), in charge of transferring the bags (8) from the training station (1) to the intermediate (2), filling (3) and closing (4) stations.

This carriage (9), which, as can be seen perfectly in Figure 2, adopts a U-shaped configuration, leaving the transfer space for the bags (8) completely transparent, is driven by a motor-reducer (10) that acts on a eccentric (11) and a connecting rod (12) that transmit to said carriage (9) an alternative longitudinal movement, whose magnitude of advance, and consequently of recoil, is exactly coincident with the distance between the bag forming station (1) and the intermediate station (2), and with the distance between the filling station (3) and the closing station (4), while the distance between the intermediate station (2) and the filling station (3) is considerably smaller.

To absorb this dimensional difference, while the pair of tweezers (7) with which the transfer is made from the bag forming station (1) to the intermediate station (2), as well as the pair of jaws (13) with which is carried out the transfer of the bags from the filling station

(3) to the closing station (4) are fixed, the pair of tweezers (14) with which the transfer is made from the intermediate station (2) to the filling station (3) is slidably mounted on guides on the carriage (9) with floating character, specifically associated with the rod (15) of a pneumatic cylinder (16), which acts as a spring or elastic element that allows free displacement of the carriage (9) once the pair of pliers (14) has been faced with the filling station (3), in a limit situation defined by a stop (17) on which said pair of pliers impacts (14) and that, consequently, is operatively facing the filling station (3), as seen especially in Figure 3.

The intermediate or waiting station (2), not only has the purpose of substantially shortening the path that the bag (8) must make, in each operating cycle, in its advance to the filling station (3), but also to facilitate the opening from the mouth of the bag (8), for which purpose said intermediate or waiting station (2), in addition to being assisted by the pair of floating jaws (14), has a clamp (18), operable by a pneumatic cylinder ( 19) and provided with suction cups (20) that acting on the walls of the sack, at the level of the mouth of the sack, perform an opening prior to the definitive opening in the filling station (3), by means of the suction cups (21) existing in this station.

In addition and as seen especially in Figure 9, the jaws (14) that move the bag to the filling station (3) are complemented at the height of the filling stage with other jaws (29) that are associated with the filling mouth and that are susceptible to transverse displacement, actuated by respective pneumatic cylinders, so that they make an approach movement that collaborates with the suction cups (21) for an optimal opening of the mouth of the sack (8) and, consequently, to optimal conditions for filling it.

In the improvement of the filling conditions of the bag (8) also collaborates a compactor element (22), located under said bag (8) in the vertical corresponding to the filling station (3), which strikes on the base of the bag to achieve the repeatedly cited compacting effect. As shown in broken lines in Figure 1, the compactor element (22) has a height-adjustable positioning, to adapt it to the dimensions of each type of bag (8), a regulation that is carried out simultaneously with that of the belt evacuation (23), for which purpose both elements are mounted on a common chassis.

Finally and in relation to the closing station (4), the mobile arm (24) of the welding clamp (25), actuated by the corresponding and classic cylinder (26), has a rear extension (27) for act on an approach sensor (28), as observed especially in figure 5, so that said sensor (28) detects exactly the spacing of the welding clamp (25), which must be the one corresponding to the thickness of the mouth of the bag and which, as previously stated, allows to detect a failure of the bag feeding, by absence thereof, a fold in the mouth of the bag determining a defective closure thereof, or any other type of anomaly detectable depending on of the variation of said thickness of the mouth of the bag with respect to the corresponding and pre-established magnitude.

According to the described structure, the operation of the machine is evident in view of Figures 1 to 8.

Specifically, figures 1 and 2 samples show the zero point, from which each cycle begins operating the machine, in which a sack (8) is in the sack-forming station (1), a second sack (8) is in the intermediate station (2), a third sack (8) is found in the filling station (3) and a fourth bag is in the closing station (4), while other bags are already completely closed on the evacuation conveyor belt (23). With the start of the operating cycle, specifically with the setting of the gearmotor (10), the carriage (9) advances by dragging the first of the aforementioned bags to the intermediate or waiting station, while a new bag conforms in the forming station (1), the second bag being directed towards the filling station (3), its bottom or lower extremity impacting on the compactor element (22), causing an inflection in said bottom that prevents product access to the lower corners of the bag, improving its conformation in the filling phase, while the third bag, which was already full, passes to the closing station (4), and the fourth and last bag, existing in said station closure, is dragged by the conveyor belt (23). At the end of the carriage advance phase (9) the intermediate station (2) is in the pre-opening phase of the corresponding bag opening, the filling station (3) carries out the filling of the bag, which has been able to start previously, thanks to the shortest route required by said bag between the intermediate station (2) and the filling station (3), and the last bag (8) has been closed at the last station (4). Then all the clamps (7), (13) and (14) open simultaneously and the carriage (9) returns to the initial position, the one shown in figure 1, to start a new operating cycle.

According to another improvement, the machine includes also a welding mechanism for reinforcing the bags, a mechanism that both as a whole and in detail is the one represented in figures 12 to 16, said welding mechanism being referenced in general with (30), which as has been said previously It is applicable to an autonomous bagging machine that uses as a raw material a continuous tubular band in the form of a coil (31), which is supplied by a feeder materialized in a pair of support arms (32), tilting with the collaboration of cylinders (4 ), to favor the maneuver of loading and lifting of the coil (31), coil on which a driving roller (34) is established, assisted by the corresponding motor-reducer (35), responsible for carrying out the unwinding of said band continuous tubular, for which said roller (34) is also mounted on a tilting arm (36) assisted by another cylinder (37).

The coil (31) supplies the continuous band to a feeding station (38), from which said band passes to the welding mechanism (30), and from here to a station (39) for cooling the welding and centering the forming sheet of the bags, being that station (39) formed by a series of rollers between which it runs in a winding path that facilitates the two tasks indicated, on the one hand the cooling of the weld and on the other the centering of the sheet, subsequently passing to the bag forming station (1), in which the operations of fragmentation of the continuous band and closing of the lower extremity of the bag are carried out, placing a carriage (9) under this forming station (1) responsible for sequentially moving the bags (8) to the filling station (2) and finally to a closing station thereof, from where they are evacuated, as said in advance

Well, the welding mechanism (30) and as seen especially in Figures 14 and 15, is constituted from a chassis (40) intended to be in solidarity with the machine frame, chassis (40) to which a spindle is integral (41), double, that is to say with two sectors of opposite threads, on which respective nuts (42) are mounted, which, when manually operated on a flywheel (43) that ends one of the ends of the double spindle (41), are they approach each other or distance themselves, depending on the direction of rotation supplied to said steering wheel (43).

To each of the nuts (42) a support (44) is integral to which a head (45) is integral, so that two conveniently facing heads (45) participate in the mechanism, each provided with them, at a medium level, a fixed guide plate (46), so that both guide plates are coplanar as shown in figure 15, these plates being intended to be housed respectively in the side bellows of the continuous tubular band of that the bags have to be obtained, acting as separators during the welding phase of said bellows, which is carried out with the collaboration, in each of the heads (45), of a clamp (47), provided with electro-heating resistors (48) of isoscelic trapezoidal configuration, which mounted with the possibility of transverse displacement on the corresponding head (45), are capable of throttling the corresponding marginal zone of the continuous tubular band, against the inter-guide plate mean (46), during the welding phase, or separating to allow the free passage of said band to a new work area on the same. As side guide plates, two sheets (49) are arranged with grooves, through which the welding heads pass through, used as guiding elements and impeding the welding heads themselves from dragging the formed material of the bag.

Specifically, in the detail of Figure 13, where the continuous tubular band has been referenced with (5), it is observed how at the level of what the cutting line (50) that makes the adjacent bags independent from then becomes, they are established, at the ends of this imaginary line (50), two welding areas (51), with the same trapezoidal configuration as the electro-heating resistors (48), so that each of these welding areas (51) will be fragmented into two after the independence and conformation of the bags, one of the two halves belonging to the bottom of a bag, while the other half corresponds to the mouth of another.

This partial throttling of the mouth of the bag does not at all hinder the subsequent filling thereof at the station (3), but nevertheless a perfect symmetry is achieved between the base of the bag and the mouth of the bag, which makes when the bag is closed present its ends formally and structurally identical.

The machine also includes, as one of the improvements, a bag forming mechanism or group, structured from a drag roller (52), assisted by a pressing roller (53), receiving the drag roller (52), through a transmission belt (54) or other similar element, the generator movement by a motor (55), with its corresponding reducer, said motor being controlled by an encoder that allows to regulate at will and with all precision the rotary movement of the drag roller (52) and, consequently, the magnitude of the continuous tubular band constituting the raw material for obtaining the sacks , which is carried forward in each operating cycle corresponding to the formation of one of said sacks. The pressing roller (53) is established between a pair of tilting arms (56), mounted on a tilting axis (57), said arms (56) being laterally movable for the necessary separation of the pressing roller (53) from the dragging roller. (52), in the initial maneuver of coupling the continuous tubular band, by means of an eccentric (59) which can be operated manually by means of a small lever (59) located on the front of the machine.

The chassis (60), support of the rollers (52) and (53), is in turn the support (61) for a funnel (62) that conveniently channels the continuous tubular band towards the cutting and welding area thereof , obviously said funnel (62) being located in the vertical corresponding to the plane of tangency between both rollers (52) and (53).

To the chassis (60), through upper axles (63), a pair of reinforcements (64) that frames the rollers (52) and (53) and the funnel (62) are swiveled together, finishing each of these reinforcements (64), by its lower extremity, in a tamper (65) acting on the corresponding side of the bag, an electrosoldering head which in figure (1) was referenced with (6), one of them in a blade (66) and the other in a sufridera (67), so that when the armor (64) is closed against each other, the first thing Acting are the rammers (65), conveniently fixing the continuous tubular band, and then the blade (66) that makes the closed bag independent in the previous operating cycle of the mechanism, and the electrosoldering heads (6) that close the bag or sack immediately following .

The tilting movement of the reinforcements (64) is achieved with a cylinder (68), preferably pneumatic, which acts on an eccentric (69) provided with two radial appendages (70) and (71) to which two connecting rods are articulated ( 72) and (73) that act simultaneously and in contrast to the aforementioned tilting armors (64), to achieve approximation or distancing movements between them.

While in the described welding and cutting mechanism, the one represented in figures 17 to 20, the maneuver of independence of a sack and closing by welding of the bottom of the next one is being carried out, at a lower level a consolidation operation is taking place of the closing weld of the immediately previous sack, that is to say of the sack that is becoming independent by cutting, for which in this lower zone the mechanism represented in figures 20 to 22 is established, consisting of a baffle plate (74) that directs the lower end of each bag to a pair of blower nozzles (75-75 '), both of adjustable positioning, the first one corresponding to the lower end of the deflector plate (75), fixed, while the second (75' ) is substantially distance from the first and is mounted on an arm (76), tilting at its midpoint (67) and which at its opposite end to the nozzle itself (75 ') receives the ac actuation of a pneumatic cylinder (78) with which the approach of the nozzle (75 ') to the nozzle (75) is carried out, once the bottom of the bag has reached the blowing zone.

These nozzles (75-75 '), as observed especially in Figure 20, are affected by a longitudinal pipe (79) for air passage, from which a plurality of outlets (80) conveniently directed towards the sack weld emerge .

As a complement to the structure described and in order to allow a height adjustment for it, allowing its adaptation to different bag sizes, the support (81) of said structure is mounted with the possibility of vertical displacement on guides (82) conveniently in solidarity with a chassis (83), which can be the chassis (60) of the machine, also collaborating with said support (81) a spindle (84) that by its free end and through a pulley (85) or similar, with the contest of the corresponding belt (86), it receives the movement of the pulley (87) of a steering wheel (88) also established on the chassis itself (83), so that acting in one direction or another on the steering wheel (88 ), the spindle (84) causes the lifting or lowering of the support (81) and, consequently, the adaptation of the deflector plate (74) and the blower nozzles (75-75 '), to the level adopted by the lower end of the sack, where its welding is located, in function ón of the planned length for it.

Claims

 R E I V I N D I C A C I O N E S ia.- Improvements introduced in autonomous bagging machines, of the type that use a continuous tubular band with side folds or bellows, as raw material for forming the bags, and in which a first bag-forming station is established , where the fragmentation of said continuous band and the welding of the bottom of each of said sacks occurs, a filling station for said sacks and a closing station after which the filled and closed sacks are evacuated by means of a conveyor belt, collaborating with these stations a lower carriage, of alternative movement, which intermittently transfers the bags from one station to another station, characterized in that between the bag forming station (1) and the filling station (3) thereof, it incorporates an intermediate waiting station (2), with the particularity that said intermediate station (2), which is distanced from the training station n of bags (1) exactly the same magnitude as the filling station (3) is of the closing station (4), is considerably closer to said filling station (3), in order to limit the transfer time of the bag to said filling station, at the expense of an increase in the time the machine devotes, in each cycle, to the filling operation itself; a welding mechanism for reinforcement of the bags being provided, provided previously to the bag forming station (1), including in the bag forming station itself a special forming group intended to fragment the continuous tubular band from the which the bags are obtained and close by welding the lower limb from each of them. 2 ^ .- Improvements introduced in autonomous bagging machines, according to claim 1, characterized in that the carriage (9) that carries out the transfer of the bags (8) between the different stations (1), (2), (3) and ( 4) has a pair of fixed jaws (7), for transfer of each bag (8) from the bag forming station (1) to the intermediate station (2), with another pair of fixed jaws (13) for transfer of the bags (8) from the filling station (3) to the closing station (4), and with a pair of floating and guided jaws (14), for transfer of the bags (8) from the intermediate station or of waiting (2) to the filling station (3), these clamps or jaws (14) being associated with a pneumatic cylinder (16), in function of elastic support element of said clamps, with which a stop (17) collaborates. ), operatively located in the vertical of the filling station (3), so that in the intermediate phase of the movement of advance of the carriage (9), before it reaches the end of its travel and when the movable jaws (14) face the filling station (3), such jaws stop, against the elastic tension of the cylinder ( 16), allowing the immediate start of the filling phase. 3a.- Improvements introduced in autonomous bagging machines, according to claim 1 ^§ , characterized in that a clamp (18) provided with suction cups (20) that are made in said intermediate station (2) is established in the intermediate or waiting station (2). a pre-opening phase of the sack mouth (8), prior to the definitive opening of the sack, at the filling station (3), by the suction cups (21) of said station, having also provided that in correspondence with the filling stations are associated with two jaws (29) that can be transverse in the direction of approach, to facilitate the maneuver of opening the bag (8). 4th.- Improvements introduced in autonomous bagging machines, according to previous claims, characterized in that the transfer carriage (9) adopts a U-shaped configuration, with its lateral branches oriented towards the exit of the machine, that is, towards the evacuation conveyor belt (23), so that said car makes the location and transfer space of the bags (8) completely transparent, from the training station (1) to the closing station (4). 5a.- Improvements introduced in autonomous bagging machines, according to previous claims, characterized in that in the vertical corresponding to the filling station (3) and at the lower level, a compactor element (22) is established on which the lower extremity of the bag rests (8) before and during the filling thereof, and hitting the base of said sack (8) to improve the filling conditions. 6a.- Improvements introduced in autonomous bagging machines, according to claim 1, characterized in that the closing station (4) has, specifically in the tilting arm (24) of its welding clamp (25), with a subsequent extension (27) intended to act on an approach sensor (28), which allows detecting any anomaly in the station caused by an approximation level between the welding heads (25) different from the preset, either by absence of sack, by an unwanted fold of its embouchure or by any other cause 7a.- Improvements introduced in autonomous bagging machines, according to claim 1, characterized in that the welding mechanism for bag reinforcement is constituted from a chassis (40), intended to be in solidarity with the machine frame, chassis (40) to which a double spindle (41) is integral, with two coaxial sectors of opposite threads, on which respective nuts (42) are mounted that approximate or distance depending on the direction of rotation supplied to the spindle (41) by a steering wheel (43 ) of manual actuation or by any other appropriate actuator means, with the respective nuts (42) supporting (44) for two heads (45) facing each other, in each of which a guide plate (46) participates, which makes the sufridera times of the welding mechanism, intermediate, destined to engage in the corresponding lateral fold or bellows of the continuous tubular band constituting the sack, and each suffering guide plate (46) being framed Ada by the arms of a welding clamp, movable synchronously and by any appropriate means, in the sense of approach or distance with respect to the intermediate and fixed guide plate, preferably constituted by two lateral guide plates (49) that carry a hole through which the soldier pliers penetrate. 8a.- Improvements introduced in autonomous bagging machines, according to claim 7a, characterized in that the welding mechanism (30) for bag reinforcement is located in correspondence with the bag forming station (1), so that said mechanism acts on the continuous tubular band (5), before it is divided into segments corresponding to the respective sacks, being as a subsequent stage to the welding equipment and before entering the sack forming stage followed by a stage (39) where the weld produced is cooled and the sheet is focused on its development, said stage being formed by a winding path achieved by the passage of said sheet through rollers. 9a.- Improvements introduced in autonomous bagging machines, according to claims 7a and 8a, characterized in that the welding pliers (48) adopt a trapecial configuration and act on the continuous tubular band (5) in correspondence with the imaginary transverse lines (50) in which the fragmentation will take place by cutting said band, the welds (51) being placed on the ends of such lines (50), each welding being of trapecial configuration and originating after the passage of the continuous tubular band (5) through the bag forming station (1), two triangular welds, one for the mouth of a bag and another for the bottom of the bag immediately following. 10 .- Improvements introduced in autonomous bagging machines, according to the 7th claims, 8a and 9a, characterized in that the welder mechanism reforzaraiento bags, is of reduced length, allowing entry and exit of the sheet of that stage can be carried out by Simple manual introduction. Improvements in autonomous lia.- bagging machines, according to claim 1, wherein the group forming bags is formed from an entraining roller (52) and a pressing roller (53), the first of which receives the movement of a motor-reducer group (55), through a suitable transmission and controlled by an encoder that allows the magnitude of said movement to be adapted to the specific length of each type of bag, while the pressing roller is suspended from a pair of tilting arms (56) and is separable from the drag roller (52), for initial coupling of the continuous tubular band (5), by means of an eccentric (58) acting directly on at least one of said arms (56) and to which a hand-operated lever (59) is integral. 12a.- Improvements introduced in autonomous bagging machines, according to claim 11 ^§ , characterized in that two reinforcements (64) are articulated jointly to both the said rollers and articulated rollers (52) and presser (53). to a funnel (62) of downstream channeling of the continuous tubular band (5), such tilting reinforcements constituting, through its lower end, the movable support means for the cutting blade of the continuous tubular band, provided in the heads of welding (6) thereof, as well as for a pair of rammers (65) that conveniently stabilize said continuous tubular band (5) during the cutting and welding phase. 13a.- Improvements introduced in autonomous bagging machines, according to claims lia and 12a, characterized in that the tilting reinforcements (64) support the cutting and welding mechanisms, are operated simultaneously and in contrast to a cylinder (68), preferably pneumatic, acting on an eccentric (69) provided with a pair of radial extensions (70) and (71), opposed, to which articulated connecting rods (72) and (73) are articulated they relate said eccentric with the tilting reinforcements (64), so that the tilting in one direction of the eccentric (69) causes the approximation of the reinforcements (64), and their tilting in the opposite direction the separation thereof. 14a.- Improvements in autonomous bagging machines, according to claim 11, characterized in that in the corresponding vertical to the funnel (62) guiding to the continuous tubular band (5) and lower level of the machine, a deflector plate is established ( 74) which leads the lower extremity of the sack towards a pair of blowing nozzles (75-75 '), one fixed and the other tilting, capable of adopting a position of marked distancing for free passage of the lower extremity of the sack, and a subsequent Approach position during the blow phase of welding. 15a.- Improvements introduced in autonomous bagging machines, according to claim 14a, characterized in that said blowing nozzles (75-75 ') are adjustable positioning, and the tilting nozzle (75') is operable by means of a pneumatic cylinder (78) . 16a.- Improvements introduced in autonomous bagging machines, according to claim 14a, characterized in that each blower nozzle (75-75 ') has a longitudinal duct (79) of air insufflation, from which a plurality of outlets or nozzles themselves arise. (80) oriented towards the welding line that closes each bag inferiorly. 17a.- Improvements introduced in autonomous bagging machines, according to claims 14a to 16a, characterized in that the blowing group is established on a support (81), vertically movable on guides (82), also vertical, that relate the support (81) to a chassis (83), while a spindle (84 ) that, by means of an appropriate transmission (86) it is related to a hand-operated steering wheel (88), so that through said steering wheel (88) the support (81) is height-adjustable, to adjust the level of the nozzles blowers (75-75 ') at different bag sizes.