EP1060988B1 - Method and device for making and applying a flexible heat-shrinkable hood on palletized load - Google Patents

Description

Technical field of the invention

The invention relates to a method and a device for shaping and removing a heat-shrinkable flexible cover on a palletized load, said cover being constituted by a bellows sheath. The packaging of Palletized shrink-wrapped loads have taken off with the appearance of the bellows sleeve for presenting the film in reel, of build a waterproof cover by welding and cutting transverse, to mechanize the opening of this cover by spreading the four ends of the bellows of the sheath.

State of the art

Most known machines have an opening device of the sheath placed above the palletised load, the latter being introduced according to an automated sequential cycle in the machine via a roller or chain conveyor.

In these machines, an unwinding coil of the heat-shrinkable sheath is placed on the ground, and its axis extends parallel to the carrier of transfer of the palletised load. The unrolled sheath rises vertically along of the machine to position its opening at about three to four meters from the ground . The operation of positioning the sheath when replacing the coil, constrains the operator to manually insert the sheath into the rolls of the opening system. This painful operation, as are also the maintenance interventions of the opening device of the sheath, imposes the presence gateways and access ladders that increase the size and cost of the installation.

Another type of machine unrolls the sheath vertically, from of a coil on the ground, and transfer horizontally by opening on all its height the section of welded sheath, positioning it above the palletised load.

Such an arrangement is suitable for low height loads, but is not applicable to pallet loads of two to 2.5 meters height that are common in the industry; the opening of the sheath, which can reach three meters in length is virtually impossible in this configuration, and the machine would require a height of about six meters, this which is often incompatible with the height of buildings intended to accommodate these facilities.

Finally, a third type of machine is used to date; it comprises a coil of film placed on the ground near a mechanism of opening, welding and cutting the film. The sheath is presented with its opening arranged at the top, and a shaper is held inside the sheath for ensure accurate positioning and ensure sufficient pre-opening.

A gripping arm pinches the sheath at the four ends of the bellows, and unrolls vertically from bottom to top; after realizing the welding and cutting of the fitted cover, the gripping arm is animated of a movement of opening, rising and rotation to come to style the palletised load placed nearby.

EP-A-92922 discloses a machine for removing a soft cover on a palletized load. The unwinding roll of the film plastic cover is not placed on the floor, but is attached to the upper frame of the machine. The film stored on the reel is already welded at regular intervals to constitute closed funds, and furthermore includes transverse cutting lines to obtain bags of fixed volumes. There is no no automatic opening mechanism of the sheath.

Object of the invention

The object of the invention is to improve the shaping process and removal of the heat-shrinkable cover, avoiding the presence of bridges and access ladders for adjusting and servicing mechanical members, and facilitating the installation of the sheath during the reel change.

• disposer la gaine sur une bobine de stockage placée sur un dévidoir au voisinage du sol,
• dérouler la gaine à partir du dévidoir, en la maintenant en position verticale avec les soufflets sollicités en écartement par un organe positionneur,
• enrouler une partie de la gaine sur un rouleau accumulateur solidarisé à un bras de transfert d'un robot de préhension,
• couper la gaine à une longueur prédéterminée et souder la partie médiane de la gaine au moyen d'une soudeuse pour obtenir une housse à fond étanche,
• et transférer la housse enroulée sur le rouleau accumulateur vers un poste de dépose sur la charge.

The steps of the process according to the invention consist in:

• arrange the sheath on a reel placed on a reel near the ground,
• unwinding the sheath from the reel, keeping it upright with the bellows solicited by a positioning member,
• winding a portion of the sheath on a storage roller secured to a transfer arm of a gripping robot,
• cut the sheath to a predetermined length and weld the middle part of the sheath with a welder to obtain a tight bottom cover,
• and transfer the wrapped cover on the accumulator roll to a dispensing station on the load.

The unwound part of the cover is opened during the transfer phase to the removal station. The cover is kept open at all four angles the quadrangular end unwelded during the unwinding phase of said sheath around the accumulator roller intervening during the movement of descent for placement without friction on the palletised load.

The method consists in presenting, from a coil on the ground, the sheath welded by a welder equipped with a cutting device placed near the sheath coil. All the mechanical parts are on the ground, and the ergonomics of the sheath placement station when changing the reel is optimized because this intervention becomes very fast. Cross weld the sheath is made in masked time, well before the opening of the cover, and is very resistant when opening the cover after cooling. In its production standby position of up to a few minutes or several hours, the internal volume of the sheath is protected by welding and prevents any penetration of ambient dust; this advantage is particularly important in glass factories where packaged products must imperatively be isolated from this dust because they are not washed when they are filled.

• une bobine de stockage de la gaine,
• des moyens de soudage et de coupe de la gaine pour constituer ladite housse,
• un mécanisme d'écartement de la gaine pendant le mouvement de descente vers la charge,
• un rouleau accumulateur motorisé sur lequel est enroulée une partie de la gaine maintenue par une pince de retenue,
• et un bras de transfert du rouleau accumulateur entre une première position d'enroulement et de coupe de la gaine, et une deuxième position de dépose de la housse sur la charge palettisée.

The gripping robot of the shaping and dispensing device according to the invention comprises:

• a storage coil of the sheath,
• means for welding and cutting the sheath to form said cover,
• a mechanism for spacing the sheath during the downward movement towards the load,
• a motorized storage roller on which is wound a portion of the sheath held by a retaining clip,
• and a transfer arm of the accumulator roll between a first winding and cutting position of the sheath, and a second position of removing the cover on the palletized load.

The transfer arm is mounted in horizontal translation on a slide, which is movable in vertical translation along a fixed frame. The mechanism distance from the sheath is equipped with four rockers equipped with gripping of the rolled sheath in the first position, and opening of said sheath in the second position.

According to one characteristic of the invention, a movable deposition arm in the vertical direction, is arranged under the pendulums, and is provided with fingers of conformation and pinching for the recovery of the sheath at four angles when of removal on the load.

A hot air shrink frame is disposed above the removal arm and is likely to move in the vertical direction by allowing the internal movement of the rockers when the removal arm grasps the sheath for setting up on the load.

The gripper robot can when transferring the cover over of the palletised load, rotate 90 ° with respect to a vertical axis. This possibility of the machine allows, from a double or triple post coil, to avoid much more difficult rotation, palletized loads having a load section relative to the direction of travel of the carrier, incompatible with the stresses width / bellows of the sheath; this case is common in the liquid food market where the size of pallets are 1000 x 1200 mm and 1000 x 600 mm on the same line of production. The length of the load on the conveyor is 1200 or 600 mm; and the second format is usually rotated 90 ° under the machine, the largest face of the load being parallel to the axis of the conveyor and parallel to the axis of the coil.

Brief description of the figures

• FIG. 1 shows a schematic view of the shaping device and depositing a heat-shrinkable flexible cover according to the invention, the load palletized being being transferred under the hulling station;
• Figure 2 shows the next step during the descent movement of the cover around the load 1 palletized;
• FIGS. 3, 4.1, 4.2, 4.3 and 5 show the different phases of gripping and winding the film by the robot, before the transfer to the post of hooding;
• FIG. 6 is a plan view of the gripper robot in position A winding and cutting the cover, then in the B position of removal on the palletized load after vertical and horizontal transfer;
• Figure 7 is an identical view of Figure 6 of an alternative embodiment;
• Figure 8/1 shows the filling station with an air shrink frame hot 19;
• FIG. 8/2 shows a detail of FIG. 8.1, the load 1 being placed on the carrier equipped with a lifting table for shaping a fold shrink film under the load laying plane;
• FIG. 8/3 is an identical view of FIG. 8/2 of a variant of FIG. realization, in which the load is placed on a pallet handling, with the interposition of a sheet of plastic material between the load and the palette.

Description of a preferred embodiment

In FIG. 1, the palletized load 1 is being transferred under the filling station, and is supported by a chain or roller table. coil 4 for storing a sheath or heat-shrinkable cover 2 is placed at ground level, on a reel next to a frame 7 of a gripping robot R. The gusseted sheath 2 is folded flat after winding on the spool 4, then is then unrolled and held in a vertical position with the bellows solicited in opening by a positioner member 6. A heat-sealing connection 5 of the sheath 2 is placed on the positioner member 6.

A welder 15 is composed of two moving jaws moving horizontally and symmetrically with respect to the positioner member 6.. upper portion of the welder 15 has a linear cutter 16 consisting of an actuating cylinder and a straight cutting blade.

The gripper robot R comprises a transfer arm 8 carried by a slide 30 movable in vertical translation on the frame 7, a roller 9 motorized accumulator equipped with an internal clamp 10, and a system of rockers 11 each provided with four gripping rollers 12. The spacing of the rockers 11 is provided by two pneumatic cylinders associated with hydraulic clamps and gear sectors 14 allowing for synchronized movement of pendulums 11.

A removal arm 18 of the cover 2 can also slide the along the frame 7, and carries four fingers 17 of conformation and pinching of the sheath 2. During the supply of the load 1, the cover beforehand made, is kept open by the rockers 11 above the post padding. The removal arm 18 is in the recovery position of the cover by the fingers 17.

The storage coil 4 of the heat-shrinkable sheath 2 is in waiting on the reel; and the sheath 2 unwound is maintained centered by the organ positioning positioner 6 for separating the bellows. The welder 15 performed the transverse heat-sealing of sheath 2, which rests on the body positioner 6 by accurately holding the sheath 2 on hold.

Detail A of Figure 1 is a cross section of sheath 2 very little open; detail B of Figure 1 is a cross section of the cover in open position.

Figure 2 represents the next step, during the movement of down the cover around the palletized load 1. The fingers 17 of the arm of 18 hold the cover open, and the gripping rollers 12 of the balances 11 ensure the open state continuously to limit the friction of the film 2 against the upper corners of the palletized load 1.

In this step, the accumulator roller 9 is motorized in the direction of unwinding, and the retaining clip 10 is open to release the area gripping film 2 at the heat seal 5. After the release of the gripping zone of the accumulating roller 9, the gripping rollers 12 deviate to release the cover, allowing the continuation of its movement descent until the coming in support on the palletized load 1.

During the step illustrated in FIG. 3, the removal arm 18 of the cover is at the end of the downhill run. The handling table of the palletised load 1 can be equipped with a lifting device 32 to optimize the positioning of the cover at the base of the support pallet. Exceeded of the sheath 2 is generally intended to be plated under the lower plane of the pallet during the retraction phase of the film, in order to secure the load 1 and the support pallet.

As soon as the cover has left the gripping rollers 12, the arm of transfer 8 of the gripper robot R is animated with a first movement of horizontal translation of, then a second downward movement of to prepare the cover for the next pallet. The height of this pallet and the corresponding length of the cover, is measured by via an ancillary measuring device. The pendulums 11 are found in the close state during this transfer phase.

An opening is formed in the accumulator roller 9 to position the gripping zone of the heat seal 5 in the retaining clip 10 after indexing by rotating the roller 9. In this step, the gripping rollers 12 are spaced apart on both sides of the positioner member 6, and the heat-sealing 5 is taken in the clamp 10.

In FIG. 4/1, the gripper robot R is positioned to allow the introduction of the gripping rollers 12 of the rockers 11 between the bellows of sheath 2. Figure 4/2 is a horizontal section in the plane of the rollers of 12, and FIG. 4/3 shows the gussets of the sheath 2 pinched by the gripping rollers 12. The deposition arm 18 is returned to the position initially raised, and is ready for a new hulling operation.

FIG. 5 represents the step of welding and cutting of the sheath 2 after its winding around the accumulator roller 9, and the vertical displacement of the transfer arm 8 up. As soon as the jaws of the welder 15 are brought closer to one another to perform heat sealing 5, the cut is made by moving the knife 16 .The gripping robot R then transfers the cover above the filling station without waiting for the end of the cycle welding.

During the horizontal translation phase of the transfer arm 8 above the overshoot station, the rockers 11 are actuated to the discarded state for ensure the opening of the unwelded part of the cover.

The return of the gripper robot R in the position of FIG. fingers 17 of the deposition arm 18 to grasp the cover at the four ends of the gussets spread. At the same time, the palletized and hung load 1 is evacuated by the transfer table, and a new load is introduced under the machine.

Figure 6 is a plan view of the gripper robot R in position A winding and cutting the cover, then in the position B of removal on the load 1 palletized after vertical and horizontal transfer to position the cover open over the load 1. This case corresponds to a load 1 transferred onto the conveyor 3, the length of the pallet being in the direction of the carrier 3.

FIG. 7 is an identical view of FIG. 6 in the case of a load transferred on the conveyor 3, the length of the pallet being perpendicular to the direction of the carrier's progress. In this case, the robot R rotates 90 ° during its transfer movement from position A to position B.

It should be noted that FIGS. 1 to 7 represent only the phase of the retraction phase of the heat-shrinkable film being carried out on a downstream station of the overpack machine. The rates of a machine according to Figures 1 to 7 can reach 200 palletized loads per hour; in place palletised loads, it is possible to directly cover any other type of products, for example household appliances.

Figures 8/1 to 8/3 show a complete machine making the houssage and the retraction on the same post. A hot air shrink frame 19 is positioned above and moving parallel to the drop arm 18 of the sheath 2. The balances 11 opening of the gripper robot R come position the open part of the cover inside the shrink frame 19 to allow the removal arm 18 to seize it and then cover the charge. The cover being deposited on the load 1, the frame 19 provides the retraction heat-shrink film by blowing horizontally a jet of hot air against the film 2 according to two distinct cycles:

In Figure 8/2, the load 1 is placed on the carrier 3 which is equipped of a lifting table allowing the shaping of a fold of the film retracted under the laying plan of the load. The removal arm 18 sets up the cover 2 after raising the load 1, and the retraction frame 19 retracted in first place the lower part of the cover, then the vertical faces of the cover during the gradual ascent.

Figure 8/3 shows the case of a cover 2 placed on a load 1 it even placed on a pallet of handling 21. A sheet of plastic material 20 is interposed between the load 1 and the pallet 21 support. The removal arm 18 remains in the low position, and the four fingers 17 ensure the positioning of the cover. The retraction frame 19 retracts the film 2 from top to bottom, thus retracting the lateral faces first, is positioned in the lower part above of the removal arm 18 to retract the cover at the height of the plane top of the pallet 21. The cover and the overflowing external part to the film format pallet are sealed to each other under the effect of heat. The removal arm 18 then disengages downwards or laterally to finish the retraction of the bottom of the cover. This case of application is common during packaging of fillers made of glass containers, for example bottles, the envelope formed to be watertight on the six faces of the charge. Retraction from bottom to top, as in the previous case, would seal in the sealed cover after heat sealing, a volume of air that would interfere with the stability of the load normally packaging.

The rates for the type of machines according to figures 8.1 to 8.3 can be to reach 120 palletized loads per hour, with a small footprint.

Claims (10)

1. Process for shaping and placing a heat-shrinkable flexible pallet cover on a palletized load (1), said pallet cover being formed by a gusseted sleeve, characterized by the following steps:

   arranging the sleeve (2) on a storage reel (4) placed on an unwinder close to the ground,

   unwinding the sleeve (2) from the unwinder, keeping the sleeve in the vertical position with the gussets urged to the spread open position by a positioning means (6),

   winding a part of the sleeve (2) onto an accumulating roller (9) securedly fixed to a transfer arm (8) of a handling robot (R),

   cutting the sleeve at a predetermined length and welding the middle part of the sleeve (2) by means of a welding machine to obtain a pallet cover with a tightly sealed bottom,

   and transferring the pallet cover wound on the accumulating roller to a pallet covering station for placing on the load (1).
2. Process according to claim 1, characterized in that the non-wound part of the pallet cover is open during the transfer phase to the pallet covering station.
3. Process according to claim 1 or 2, characterized in that the pallet cover wound horizontally onto the accumulating roller (9) undergoes a pivoting movement through a quarter-turn during the transfer phase to the pallet covering station.
4. Process according to one of the claims 1 to 3, characterized in that the pallet cover is kept open at the four corners of the non-welded quadrangular end during the unwinding phase of said sleeve around the accumulating roller (9) taking place during the downward movement for fitting without friction on the palletized load (1).
5. Device for shaping and placing a heat-shrinkable flexible pallet cover on a palletized load, said pallet cover being formed by a gusseted sleeve (2), which is placed on a palletized load (1) by means of a handling robot (R) comprising:

   a storage reel (4) of the sleeve (2),

   means for welding and cutting the sleeve to form said pallet cover,

   and a separating mechanism for keeping the sleeve spread open during the downward movement towards the load (1),

   characterized in that the handling robot (R) comprises in addition:

   a motor-driven accumulating roller (9) whereon there is wound a part of the sleeve held by a securing grip (10),

   and a transfer arm (8) of the accumulating roller (9) between a first position for winding and cutting the sleeve and a second position for placing the pallet cover on the palletized load (1).
6. Device according to claim 5, characterized in that the transfer arm (8) is mounted with horizontal translation on a slide (30), which slide is movable in vertical translation along a fixed frame (7), and that the separating mechanism of the handling robot (R) can pivot through 90° depending on the positioning of the support pallet on the transporter (3).
7. Device according to claim 5 or 6, characterized in that the sleeve separating mechanism is equipped with four members (11) provided with rollers (12) for gripping the wound sleeve in the first position and for opening said sleeve in the second position.
8. Device according to claim 7, characterized in that a placing arm (18), movable in the vertical direction, is arranged under the members (11) and is equipped with shaping and gripping fingers (17) to take up the sleeve (2) at the four corners when the latter is placed on the load (1).
9. Device according to claim 8, characterized in that a hot air retraction frame (19) is arranged above the placing arm (18) and is able to move in the vertical direction enabling internal movement of the members (11) when the placing arm (18) picks the sleeve (2) up to place the latter on the load (1).
10. Device according to claim 9, characterized in that the hot air retraction frame (19) becomes active for retraction as soon as the sleeve (2) is positioned by the placing arm (18) either in the upward direction after said arm has been removed or in the downward direction with the sleeve being held by said arm until the end of retraction of the bottom part of the sleeve.

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