EP0070549A1 - Apparatus for continuously wrapping a palletized load with a stretch cling-film - Google Patents

Abstract

Machine for applying wrapping film to a loaded pallet has a reel of film supported on a trolley which travels around the pallet on a course fixed by a guide rail which is engaged by the inboard wheels of the trolley. The trolley axles are splayed to suit the radius of the guide rail track. Used for applying windings of self-adherant stretch film to pallet loads of varying size. The mechanical trolley and its guidance system is simple and reliable to construct and operate. No energy is employed in supporting and turning the loaded pallet, unlike turntable-based wrapping machines.

Description

The subject of the present invention is a process for continuously wrapping a palletized load with a self-adhesive stretch film.

The invention further relates to an apparatus for carrying out the method.

It is known that many types of goods are shipped after being placed on pallets. In most cases, this shipping method requires that the goods be completely wrapped both to protect them from the weather and to prevent their dispersion.

A type of apparatus is known for developing palletized loads or also groups of goods implemented manually, with notable losses of time.

A wrapping machine is also known, which comprises a solid base on which a table can be turned, the loading plane of which is a short distance from the ground. On the fixed frame of the machine rises a structure in which a reel of stretchy and self-adhesive type film can move vertically. In this machine, the palletized load is therefore placed above the ground and can then rotate around its own vertical axis while unwinding like a ribbon the film of the reel which has a fixed axis of rotation.

The latter type of installation has given good results in use, in particular when it is inserted into a packaging line. On the other hand, it is difficult to move because of its high weight; and its cost is quite considerable.

According to a subsequent installation already known, a drive unit moves the assembly which wraps the film around the material to be wrapped. In this installation, the drive unit is guided by means of a plasse in the form of a painted strip and, at the limit, it is also guided by hand. The optical guide means as has been provided, however, does not prevent the unit from accidentally leaving said bent; in addition, as a whole the installation is very expensive, both to order and for its maintenance.

Finally, the tensile force to which the film is subjected, for avoid moving it from the said route, is strictly limited to the weight of the unit itself, as well as to the grip of the wheels on the ground.

Also, the mechanical guidance system provided for the same installation requires the presence of a groove, which is executed in the ground or else a mechanical guide which is installed above the ground and between which penetrate an axis which, in the form of a feeler. , controls the orientation of the unit's wheels so that the same follows the planned pattern.

Besides its very high taste, it follows that with the installation in question it is necessary to carry out the operation of wrapping the film always at the same point.

The object of the present invention is to provide a method and an apparatus, which is autonomous, efficient and light in its construction, and which lends itself well to use, both in large and in small industry, due to the its simplicity, its low cost and its great flexibility of use.

According to the invention, this object is achieved by the fact that the carriage, actuated by a motor and carrying the reel of stretch film is guided, in its circular movement by means of a guide assembly which is supported on the ground itself, the guide assembly further having a flat conformation and such to be easily passable by a lifting means of transport.

Advantageously, this coil performs a vertical movement, upward and downward in synchronism with the advance of the carriage actuated by a motor.

The apparatus for carrying out the process is characterized in that from the base of the carriage rises a first column for the cyclic displacement in vertical direction of the coil, along said column the coil being movable by means of 'a support, mounted cantilevered relative to said column; the coil being preferably oriented radially with respect to the column, and in the direction of the palletized load, and that the said vertical displacement of the coil and the displacement along a circular trajectory of the sout trolley adjustable independently of one another and actuated by separate groups of motors arranged on the base of the carriage.

For clarity, the accompanying drawings represent a preferred non-limiting embodiment of the subject of the invention.

• la fig. 1 est une vue schématique en plan, montrant la disposition de l'ensemble de l'appareillage vis à vis de la charge palettisée,
• la fig. 2 représente schématiquement une vue en plan de l'appareil tournant autonome,
• la fig. 3 est une élévation fron xale partielle de l'appareil tournant,
• la fig. 4 est la section I-I indiquée sur la fig. 1,
• la fig. 5 représente schématiquement une portion de coupe radiale d'un appareil suivant l'invention, avec prise de courant et guidage axial de l'appareil en position supérieure.

More specifically:

• fig. 1 is a schematic plan view, showing the arrangement of the whole apparatus with respect to the palletized load,
• fig. 2 schematically represents a plan view of the autonomous rotating device,
• fig. 3 is a partial frontal elevation of the rotating apparatus,
• fig. 4 is section II indicated in fig. 1,
• fig. 5 schematically represents a radial section portion of an apparatus according to the invention, with socket and axial guidance of the apparatus in the upper position.

The apparatus shown in the figures comprises a carriage consisting of a base 1, provided, from below, with a first set of wheels T1 in the front part, on the right in Figure 2, and a second set of wheels T2 in the rear part.

In the tread of the internal wheels 2, 3 a groove 2 ′, 3 ′ has been dug while the tread of the external wheels 4, 5 is cylindrical and smooth. In addition, the wheels 3, 4 and 5 are mounted idly while the internal and rear wheel 2 is keyed onto its shaft 6 which is motor. The wheels are preferably made of synthetic plastic, known in the trade under the name of "Vulkollan".

Advantageously, the extensions of the two axles T1 and T2 overlap at point C, this point coinciding with the center of an annular base AC better described below. Said point C is furthermore at the intersection with the ground of a vertical axis passing approximately at the center of a palletized load PZ.

In addition to the drive wheel 2 is pinned on the shaft 6 a pinion 7 actuated by an electric geared motor group 8 (300 Watts, 24 volts) via a pinion 9 and a chain 10.

On the side of the train of the front wheels T1, on the base 1 of the carriage is fixed a series of two batteries 11, superimposed, of 12 volts each, to supply the said gearmotor group 8 and another gearmotor group 12 the latter provided with a possibility of reversing its movement.

Still in the front portion, far enough from the rear wheel train T2 is disposed a first column 13, along which is movable, in an upward axial movement or descending, a sleeve assembly 14 provided with a support 15 making it possible to mount on it a coil 16 whose vertical axis 16 'is parallel to the axis of the column 13.

Preferably the reel 16 is oriented radially inwards, relative to the column 13, so that the angle α made by the film during unwinding with the palletized load is always the smallest passible.

Due to the tension F of the film during unwinding with the reel, or relatively during winding on the palletized load, there follows a torque on the reel itself, relative to column 13. This torque is balanced by a second column 17, via a support 15 secured to the coil support 16 already mentioned.

The periodic upward and downward movement of the coil, and this preferably in synchronism with the advance of the device on the annular base AC, is controlled by the electric geared motor group 12 whose operation is reversible. On its drive shaft is mounted a grooved pulley 19 for winding and unwinding a traction element 20, for example a belt or chain.

By means of a return pulley 21 mounted at the top of the first column 13, the other end of the chain is joined with the guide sleeve 14, or respectively with the support 15 of the reel 16.

The amplitude of the coil travel in the vertical direction is determined by microswitches 22, 23.

On the said series of batteries 11 is superimposed a box 24, containing all the electrical control members which we will not describe further.

The planar annular base AC of FIG. 1 can be crossed by any lifting means. It consists of a ring 25, of steel strip and of a guide rail 26 obtained from a soft iron profile of preferably circular or rectangular section, itself shaped as a ring, and which is fixed to the base itself, for example by electrical welding.

The base can be made in one piece or be made up of several annular segments.

• - autonomie des mouvements, l'unité d'emballage pouvant fonctionner hors de tout bâtiment et de son système d'alimentation électrique.
• - possibilité de retirer le chariot de sa base annulaire, aucune liaison électrique n'existant entre les deux. On peut par exemple utiliser le même chariot sur plusieurs bases successives, de rayons de courbure différents. Un simple réglage de convergence des essieux non représenté suffisant à cette adaptation.
• - sécurité d'emploi, en particulier en ce qui concerne l'électrocution du personnel, étant donné que les tensions employées sont faibles.
• - utilisation de l'énergie avec meilleur rendement, ce qui est bien connu en ce qui concerne les propriétés des moteurs de traction à courant continu.
• - faible coût de réalisation d'un appareil selon l'invention.
• - faible coût d'entretien du matériel, ceux-ci entrant dans l'ordre de grandeur des frais d'entretien des batteries pour les chariots élévateurs ou véhicules automobiles de l'entrepise (hors la partie mécanique).

According to a preferred form of the invention, the motors for controlling the rotational and vertical movements are DC motors, powered by battery, which offers the following advantages:

• - autonomy of movement, the packaging unit being able to operate outside any building and its power supply system.
• - possibility of removing the carriage from its annular base, no electrical connection existing between the two. One can for example use the same carriage on several successive bases, of different radii of curvature. A simple adjustment of convergence of the axles not shown sufficient for this adaptation.
• - job security, in particular with regard to electrocution of personnel, given that the voltages used are low.
• - use of energy with better efficiency, which is well known with regard to the properties of DC traction motors.
• - low cost of producing an apparatus according to the invention.
• - low maintenance cost of the equipment, these being part of the order of magnitude of the battery maintenance costs for forklifts or motor vehicles of the company (excluding the mechanical part).

Furthermore, the apparatus produced according to the invention has great trajectory security, given that the guidance by the annular base AC is positive and that there is no risk of the carriage leaving in the workshop of 'a rectilinear movement.

According to another embodiment, the electric motors are supplied by the network. In this case, from the upper end of the columns 13 or 17 extends radially inward, that is to say in the direction of a vertical axis passing through the center C, a b.ras provided with a socket friction current (fig. 5) which has just fed in the center of the installation.

It is further planned in this embodiment to give up the function of guiding the annular base AC by making an AR arm serving simultaneously as a socket outlet and means for guiding the whole apparatus in rotation, by moving the center of rotation of the assembly upwards at C 'for this purpose and fixing it, for example, on a wall or a column.

Finally, provision is made to replace, at the user's convenience, the electric motors with internal combustion engines.

It is understood that various modifications can be made to the invention described and illustrated above according to a preferred embodiment without departing from the scope of this invention.

Claims (10)

1. Method for continuously wrapping a palletized load or a set of objects grouped under a stretch and self-adhesive film, load which is placed on the ground and in the center of a circular guide path on which moves, following a circular trajectory , a carriage actuated by motors and carrying a reel of stretch film, the said film unwinding in a direction such that it continuously envelopes the palletized load, characterized in that the carriage, actuated by a motor (8) and carrying the reel (16) of stretch film is guided in its circular movement by means of a guide assembly (25, 26) which rests on the ground itself, the guide assembly further having a flat conformation and such to be easily passable by a lifting means of known type of transport. 2. Apparatuspour execution of the method according to claim 1, comprising a carriage with a base which is supported by two sets of wheels dant axes converge towards the center of the guide assembly (25, 26), characterized in that that from the base (1) of the carriage rises a first column (13) for the cyclic displacement in the vertical direction of the coil (16), along said column the coil being movable by means of a support (15), mounted cantilevered with respect to said column (13); the reel (16) being preferably oriented radially with respect to the column (13) and in the direction of the palletized load, and that the said vertical movement of the reel and the movement along a circular trajectory of the carriage are adjustable independently of one of the other and powered by separate motor groups (8, 12) and arranged on the very base of the carriage. 3. Apparatus according to claims 1 and 2, characterized in that the first column (13), for the displacement in the vertical direction of the coil (16), is located in the front part of the carriage and at the same time far from the train rear wheels (T2). 4. Apparatus according to claim 2, characterized in that the wheels (2, 3) of the carriage, located inside or closest to the center of gyration C of the carriage are provided with grooves (2 ', 3') in which penetrate a guide (26) integral with the flat base (25), for movement along a circular path of the carriage. 5. Apparatus according to claims 1 e 2, characterized in that parallel to the first column (13), for vertical guide of the overhang support (15) of the coil (16), on the carriage is provided a second column (17) to absorb and to compensate for the torque due to the unwinding and application of the film to the load. 6. Apparatus according to claim 2, characterized in that the cyclic movement up and down the coil (16) is controlled by a motor-reducer assembly (12) having a reversible movement; on the motor shaft of said assembly being fixed a pulley (19) for winding and for unwinding a traction element (20) for raising the reel (16), being further provided a return pulley (21), applied to the first column (13). 7. Apparatus according to claim 1, characterized in that the extent of movement of the coil (16) in the vertical direction is adjustable by means of microswitches (22, 23). 8. Apparatus according to claim 1, characterized in that the assembly for guiding the carriage is constituted by a ring which is in planar and circular form (25), on the upper face of said ring being integral with a profile (26 ) for guiding along a circular trajectory of said carriage. 9. Apparatus according to claims 1 and 7, characterized in that the displacement and planar guide assembly (AC) is composed of a plurality of segments. 10. Apparatus according to claims 4, 7 and 8, characterized in that at least the internal wheels (2, 3) of the carriage are provided with grooves (2 ', 3') on their circumference, and that the wheels, guided by the said profiles (6) and by means of the grooves (2 ', 3') at the same time adhering against the flat base (25).

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