ES2252617T3 - PACKING MACHINE WITH TWO OPPOSITE COILS AND CORRESPONDING PACKING PROCEDURE. - Google Patents

Abstract

Packaging machine of the type comprising at least one pair of opposing stretch film dispensing units (3a, 3b), mounted in rotation-translation around a load (C) to be packed, the stretch film coming from the first unit attached to the film from the second unit at least during a packing stage, characterized in that it further comprises a splicing device (4) suitable for intercepting, on the axis of rotation, the portions of film that extend between the load (C) and the opposing film dispensing units (3a, 3b) to separate them and to restore the continuity of the film parts that extend between the opposite units and the film parts from the packed load.

Description

Packing machine with two opposite coils and corresponding packing procedure.

The present invention relates to a machine of packing and the corresponding packing procedure, in particular to a packing machine provided with two coils opposite.

As is known from the prior art, the Packaging machines are machines suitable for packing a load with a plastic film, usually a stretchable film. He Cargo packing is produced by establishing a movement relative rotation-translation between a coil of stretchable film and said load: under normal conditions, this it can be produced by keeping the load fixed and moving the coil to its around or by combining the rotation of the load with the translation of the coil parallel to the axis of rotation of said load.

It is also known in the prior art that One of the most important problems in this area is to control the release point of the film on the load to be pack, both at the beginning and at the end of the operation of packed. In fact, on the one hand, the free end of the movie must adhere to the load in the initial phase of the packaging and, for other part, in the final phase of the packaging, the end of the film  it must be fixed to the load, cut and fixed again.

These operations according to the prior art, are performed by means of a complex gripping device that is suitable for grabbing the end of the film, and carrying it on the load, hold it in position until it is blocked by next layers of film, join it (for example, by welding) to the final packaging and then separate it from said packaging.

In order to perform this operation, the grip device is very complex and high cost, both for its manufacturing as for its maintenance.

In addition, to be able to intervene in the film that adheres to the side of the load, the gripping device must move from a lateral position to a position where intercepts the area near the load, leading to problems of Security for its users.

For all of the above, it is desirable Avoid using this kind of device.

Another problem concerns the performance of packaging machines, which is limited by the speed of rotation maximum (of the coil or of the load) that can be realized so that the Machine work normally. In fact, in the loading version swivel, for speeds higher than typical 15 turns / minute, unbalancing pairs are produced whose cause is the unavoidable eccentricity of the load while in the version of rotating coil, for speeds greater than 40-50 turns / minute, high effort occurs inertial and the so-called "parachute effect" is generated on the stretch film, which compromises the stability of the packed.

In addition, it should also be noted that the maximum nominal speed cannot be reached in a very short time because considerable inertial masses are involved. For the therefore, part of the performance is also lost due to initial / final transients.

For the above, it would be desirable have a packaging machine that provides greater amount of film per lap, so that the performance, although within the speed tolerance range of packed.

WO 00/53497 discloses an apparatus film packaging according to the preamble of claim 1, and comprising two or more packing heads. The movie is undergoes independent traction from each head and joins a point of a load by the respective grab units and It is then packed around said load. The movie is provides at high speed per lap but it still You need a plurality of gripping devices.

Therefore, an object of the present invention It is a multi-head packing machine with a simpler construction.

These objectives are achieved through a packing machine as described, in its characteristics essential, in the attached claim.

According to other aspects of the invention, a joining device according to claim 5 and a method of packing the cargo according to claim 7.

Other features and advantages of the machine according to the invention will become more clearly apparent from of the following detailed description of an embodiment preferred, given by way of example and illustrated in the drawings Attachments, in which:

Figure 1 is a plan view of one form of embodiment of the invention;

Figure 2 is a front elevation view of the embodiment of Figure 1, in which the units dispensers are elevated;

Figure 2A is a sectional view taken at along line II-II of Figure 1;

Figure 3 is a view similar to that illustrated in Figure 2, with the packaging machine running;

Figure 4 is a longitudinal section view of a preferred embodiment of the splicing device according to the invention;

Figure 5 is a sectional view taken at along the V-V line of Figure 4;

Figures 6A and 6B are plan views and in side elevation, respectively, of the cutter cup mounted on the device illustrated in Figure 4;

Figures 7 to 18, marked with A, are partial views in longitudinal section of the illustrated device in Figure 4 during the different stages of knotting; Y

Figures 7 to 18 marked with B, are partial views from the bottom of the illustrated device in Figure 4, during the different stages of knotting.

A packing machine is illustrated in Figure 1 by way of example. It comprises two vertical support columns 1a and 1b on which is mounted, in a portable way, a annular structure 2, which is designed to support and guide the Stretch film dispensing units during rotation. An annular bearing race, located in the structure, is positioned so that it surrounds a load C to be packed. These elements will not be described in more detail since they belong to the prior art known to those skilled in this field.

According to the invention, in the annular structure 2 two dispensing units are placed facing each other, a stretchable film P continuously extending between one unit 3a to the other unit 3b (as can be seen in Figure 2). The dispensing units are composed, in a manner known per se , by a shelf that rotatably supports a coil of stretch film B and a plurality of cooperating cylinders of a pre-stretching unit.

Since the film P extends between one and another unit, along the diameter of the annular structure, is possible to attach it to the top of the load C without using a gripping device to manipulate a free end of the movie.

The operation of the machine, according to the invention, is carried out in such a way that the load C moves to a position corresponding to the axis of rotation a-a ', when the annular structure 2 is fully in position high. In this situation, the P movie, which extends to the along the diameter of ring 2, it does not intercept load C; for the therefore, it is possible to provide that the two dispensing units 3a and 3b They are already spinning.

Then the structure is lowered cancel 2 until the film is deposited on top of load C; at this time, the P film is seized so natural and maintained by the upper edges of load C, which Makes the actual packing start.

Since the points of application of the film are two at a time, it is possible to set a packing step higher (provide the ratio V / R, where V = speed of vertical translation of the ring and R = rotation speed of the dispensing unit around the load) than when using a single coil, because packing cohesion is also obtained due to the partial overlap of the two opposite passing lines of the stretch film (see Figure 3).

In summary, this allows to increase the productivity and thus achieve a first objective of the invention. He  fact that the two coils of stretch film are continuously joined, according to the previous view, immediately from the beginning does not require that the packing cycle be initiated from a coil stop condition and prevents further loss of productivity due to the initial transitory.

In addition, since the coils are located a versus another, the machine has balanced masses, which implies in less effort and can be supported by one more structure light

The possibility of doubling almost productivity, in relation to prior art machines, it can be leverage to get "standard" results in terms of film dispensed per unit of time, but reducing the rotation speed of the dispensing units, with the consequently greater reduction of effort and offering a advantageously lighter and more economical structure. In addition, a lower rotation speed results in a parachute effect reduced on the film, thus improving the quality of packed.

As can be deduced, once the packed, the film should be separated from the load and return to initial continuous conditions. For this purpose, according to the invention, a splicing device 4 located by over the load.

Due to the fact that the film extends to along the diameter of the annular structure 2, it is very easy determine, at the center of rotation, a single junction point of film in which the splicing device has to be placed.

It follows from the above that the device for splicing 4 can avoid the use of complicated or other probes Location and grip elements of the film.

According to a preferred embodiment of the invention, the splicing device 4 is mounted, on the axis of rotation a-a ', on a frame 5 placed by above the annular structure 2. The frame is mounted, so transferable, in columns 1a and 1b (Figure 2A). For example, him ring 2 and frame 5 can both be mounted on respective support shelves coupled with a fixed chain 6 common (only a part of which is illustrated in Figure 2A). During the lifting stage, the frame 5 rests on the part upper of the annular structure 2. Once reached the height desired, a suitable ratchet 7 prevents relative movement between the frame 5 and the chain 6, so that the splicing device 4 in position despite possible ring drops 2.

The splicing device 4 must be suitable to join the two ends of the film that come from the load, once the packing operation is finished, separating them from the respective coils and rejoining the free ends of the two coils to restore the initial conditions.

This operation can be performed with different techniques, for example by welding, gripping, stapling, glued, etc. It will be illustrated below, with reference to the Figures 4 to 18B a preferred embodiment of said splicing device

Figure 4 illustrates in detail a splicing device in a preferred embodiment. It consists of a housing and support structure 10, in which they are provided a main grip element 11 and a pair of secondary grips 12a and 12b, which are located in position opposite relative to the main gripping element 11. The structure housing has a protective housing 10a at its end bottom, from which several grip elements protrude.

Secondary grabs 12a and 12b are mounted on fifth wheel means 13 that allow its rotation concentric in relation to the main gripping element 11. The fifth wheel means 13 are designed to rotate, with angles of rotation of ± 180 °, by means of a driving element 14 and a transmission chain 14a (Figure 5).

Secondary grips have pins of grip 15a and 15b that can be moved by actuators 16a and 16b, inside small hollow cylinders 17a and 17b.

The main grip element 11 is composed by a main grip pin 18 that can slide, by means of an actuator A1, inside a hollow cylinder or pin 19 which, in one piece with the A1 actuator, can slide, to its instead, within an inner lining 20 by means of a second A2 actuator.

A cutting cup 21 is also joined together in solidarity with the structure of the inner lining 20, in a concentric position relative to the main grip element 11. Said cutting cup 21 is clearly illustrated in Figures 6A and 6B and consists of cylindrical protective walls 21a, interrupted by windows in which cutting blades 21b are mounted in opposite facing edges.

The combination of grip operations of the four actuators 16a, 16b, A1 and A2, together with the rotation alternating of the two secondary grabs is suitable for get a knot in the stretch film, which separates you from the load and form another junction node to start a new cycle of packed. This operation is illustrated in detail below.

The splicing device moves in the proximity of the upper part of the load C; initially the secondary grip pins 15a and 16b are removed inwards (that is, not protruding from the lower profile of the housing 10a), while the main gripping element 11 is in its position completely removed. In this way, the two coils, while turning and rising vertically, some also apply turns (2 or 3) of stretch film on the outer surface of cylinder 19 and then rise further up before stopping In this situation, which is illustrated in Figure 7A, two parts of the film move upward from the load C, pack the cylinder 19 in a plurality of turns and at then it moves up in the direction of the respective coils B.

At this point, the cylinder 19 rises until the turns of the film are flush with the mouth of the inner lining 20. The grip pin is lowered 18, being provided with a grip flange 18a and then made turn the coils around the axis a-a ' to apply at least one additional round of film below the previous ones (Figure 8A).

At this point, also the grip pins 15a and 15b of the secondary grips are lowered and the P film is packed around them at a certain angle suitable to ensure a good retention effect once it is Close the gripper element again (Figure 9B).

Until now, the film always goes through under the profile of the housing 10a and the cutting cup 21.

Subsequently, the grip pins 15a and 15b are closed and, during this fixing operation, drag and Nozzle the film P. Since the grip plane of the pins 15a and 15b is located at a higher level than the profile bottom of the housing 10a and the cutting cup 21, the film P, stretched on a cord, it moves inside the windows of the cutting cup 21 (see Figures 10A and 10B). At the same time, also the central grip element 18 fixes the last turn of the P film applied against the edge of the cylinder 19.

At this point, the actuator 14 is operated to the two secondary grip pins rotate according to the arrows G (Figure 11B).

As soon as an angle of 30º is covered, the two parts of the film that extends between the central pin and the two secondary pins intercept the two cutting blades 21b, thus obtaining the corresponding cut (Figure 12B): in this cutting stage, the film from the packed C load (whose ends remain hanging from the center grip pin) it separates the two parts of film from the two reels (which remain seized and held by the two pins secondary).

Then the cylinder 19, together with the grip pin 18, between which the last round of the film, rise integrally throughout the inner lining 20, displacing the last turn of the film inside and above the previously applied turns: in this way, you get an untreated knot that, also doing use of the elasticity of the material of the turns, establishes a stable bond between the two ends of the film coming from the packed C load (Figure 13B).

Meanwhile, the two secondary pins have completed a 180º rotation in the direction of arrow G.

Subsequently, the main pin 18 and the cylinder 19 are again subject to descent (Figure 14A) to be able to apply some new turns (2 or 3) of stretch film by a new rotation of the two coils. Then it perform the described step again with reference to Figures 9 and 10; that is, the cylinder 19 rises until the layers are pushed against the edge of the inner lining 20 while it is made Lower pin 18 through a small section. A part of the film held by secondary grips is packed over this last section of the pin, forming at least one half turn; this situation is obtained by means of a rotation inverted approximately 180º (in the direction of arrow G ') of the two grip pins 15a and 15b (Figure 15B). The last rotation is possible, even though the film cord is set at both ends, due to the high elasticity of the film. In this counter-rotation, there is no risk of that the film is cut by the blades 21b because, in this direction of rotation, the cutting cup 21 has a function protective

Next, the grip pin 18 is raised and the last half turn between the flange 18a and the mouth of the cylinder 19. The ends of the film that are still attached by the secondary pins they can be free (Figure 16B) and the A2 actuator is actuated again to make a knot - identical to the one described above - also among the latter turns (Figures 17a and 17b). In this way, the continuity of the film that extends between the coils opposite (Figure 18B), so that the initial conditions are restored to perform a new packing cycle.

A person skilled in the art will clearly appreciate that the splicing device described above and said procedure should not be construed as limiting the invention, but only represent one of his accomplishments preferred.

By means of a splicing device generic, according to the teachings of the invention, it is possible to join the free ends of the film to the packed load, unused complicated palpation devices or grip systems that they should move, in a transversal sense, in relation to the packing machine, thus achieving a new objective settled down.

In addition, the central position of the device for splicing allows it to be incorporated into other equipment useful for the packaging, for example a so-called "small press" for unstable loads.

The specific splicing device, illustrated in the preferred embodiment, allows preferably join the ends of the film by its knotting; This technique is much more reliable and less unstable than the traditional welding technique, thus becoming a new advantage of the invention.

Claims (10)

1. Packaging machine of the type comprising at least one pair of opposing stretch film dispensing units (3a, 3b), mounted in rotation-translation around a load (C) to be packaged, the stretch film being suitable of the first unit attached to the film from the second unit at least during a packing stage, characterized in that it further comprises a splicing device (4) suitable for intercepting, on the axis of rotation, the portions of film that extend between the load (C) and the opposing film dispensing units (3a, 3b) to separate them and to restore the continuity of the film parts that extend between the opposite units and the film parts from the packed load. 2. Machine according to claim 1, wherein said splicing device (4) is suitable for cutting said parts of film and to knot its free ends. 3. Machine according to claims 1 or 2, in which said dispensing units (3a, 3b) comprise at least a coil of stretchable plastic film (B) and a unit of pre-stretched and are mounted to rotate in a annular bearing race structure (2), being able to perform a translation movement with respect to the load (C) along the axis of rotation. 4. Machine according to claim 3, wherein said splicing device is mounted on a frame that can carry out a translation movement vertically (5) suitable to support the annular raceway structure (2), but that can be decoupled from said structure and locked to along the vertical direction. 5. Splicing device intended for intercept and join the parts of film that extend between two opposite coils in a packing machine according to the claim 1, comprising a main central grip element (11), constituted by a grip pin (18) that can slide inside of a hollow cylinder (19) which in turn can slide inside a inner lining (20), and a pair of secondary grips (12, 12b), located in opposite positions in relation to the element of main grip (11) and suitable for fully pivoting around the longitudinal sliding axis of said element of main grip (11) to perform knot sequences in said part of plastic film. 6. Device for splicing according to claim 5, further comprising blade means (21b) disposed between said main grip element (11) and said secondary grips (12a, 12b) and suitable for intercept and cut said film at a specific stage of said knotting sequence 7. Packaging procedure a load, in which at least a couple of opposing stretch film dispensing units (3a, 3b), performs a rotational and translational movement around the load (C) to obtain a series of turns of packaging of the film, characterized in that the film from the first unit is attached to the film from the second unit at least before and during the packing operation of the load, then being separated after the packing operation and assembled before Start of the next packing operation. 8. Packaging procedure according to claim 7, wherein the pair of dispensing units (3a, 3b) rotates before the start of the packing operation, in a position such that the set of the two units and the film that stretches between them does not interfere with the load when this last one is introduced into the packing machine on the rotation axis of said pair of dispensing units. 9. Packing procedure according to claims 7 or 8, wherein, at the end of the operation of packed, the two ends of film coming from the load and directed towards the dispensing units (3a, 3b) are cut and gathered to restore the continuity of the film between two dispensing units and between the two ends coming from The packed cargo. 10. Packing procedure according to claim 9, wherein said joining stage intended for restore the continuity of the film, involves the knotting of The ends of the movie.