Process for packing stacked items and enabling handling by a fork-lift truck

Abstract

 A process comprising a first stage consisting in arrang­ing items in the form of a substantially parallelepiped stack (2) wherein at least the bottom layer (3) is narrower than the others, so as to form a pair of steps, and wherein, between the aforementioned bottom layer and the others, there is placed a sheet (5) of a first meltable material; a second stage wherein a first strip (10) of a second heat-­shrinkable material is wound about the four surfaces of the stack perpendicular to a first vertical plane, so as to form a first continuous loop; a third stage wherein a second strip (15) of the aforementioned second material is wound about the four surfaces of the stack perpendicular to a second vertical plane perpendicular to the aforemen­tioned first vertical plane, so as to form a second loop; a fourth stage wherein the assembly so formed is heated, so as to at least partially melt the aforementioned strip and sheet material and seal the free ends of the same; a fifth stage wherein the strip portions overlapping the aforementioned steps are deformed permanently in such a manner as to adhere to the surfaces of the same; and a sixth stage wherein the assembly so formed is cooled for shrinking the material and so forming the package.

Description

[0001] The present invention relates to a process for packing stacked items and enabling handling by a fork-lift truck. Stacked items are usually packed and handled on pallets having openings into which are inserted the arms of a fork-lift truck.

[0002] The stack formed on the pallet is usually packed in rudi­mentary manner, very often using no more than strips of deformable material, for ensuring the pack is held firmly together on the pallet during handling.

[0003] Such packing involves a number of drawbacks. Firstly, it requires the use of a pallet which, being fairly expen­sive, must be salvaged for further use. Secondly, it in­volves additional work for transporting and storing the pallets, which further increases running cost. Thirdly, the volume of the package so formed is greater than that of the component items stacked on the pallet.

[0004] The aim of the present invention is to provide a process for packing stacked items and enabling handling by a fork-­lift truck, which process involves none of the aforemen­tioned drawbacks associated with the use of pallets.

[0005] A further aim of the present invention is to provide a process for packing stacked items and enabling handling by a fork-lift truck, which process dispenses with the use of pallets, and provides for packaging which is sub­stantially indeformable during normal handling and stor­age.

[0006] A further aim of the present invention is to provide a packing process of the aforementioned type whereby the packed items are sealed in substantially airtight manner. With these aims in view, according to the present inven­tion, there is provided a process for packing stacked items and enabling handling by a fork-lift truck, charac­terised by the fact that it comprises at least a first stage consisting in arranging the said items in the form of a substantially parallelepiped stack wherein at least the bottom layer is narrower than the others, so as to form a pair of steps, and wherein, between the said bottom layer and the others, there is placed a sheet of a first meltable material, the size of the said sheet being slightly greater than the stack resting on the same, so as to produce free end portions of the said sheet; a second stage wherein a first strip of a second heat-­shrinkable material is wound about the four surfaces of the said stack perpendicular to a first vertical plane, so as to form a first continuous loop; a third stage wherein a second strip of the said second material is wound about the four surfaces of the said stack perpendi­ cular to a second vertical plane perpendicular to the said first vertical plane, so as to form a second loop; the width of the said strips being slightly greater than that of the lateral surfaces of the said stack about which they are wound, so as to produce free overlapping strip end portions; a fourth stage wherein the assembly so formed is heated, so as to at least partially melt the said strip and sheet material and so seal the said free ends of the same; a fifth stage wherein the said strip portions over­lapping the said steps are deformed permanently in such a manner as to adhere to the surfaces of the same; and a sixth stage wherein the assembly so formed is cooled for shrinking the said material and so forming the pack­age.

[0007] The process according to the present invention will be described, by way of example, with reference to the accom­panying drawings showing schematic views of the basic stages involved, and in which :

Fig.s 1 and 2 show two perpendicular side views of the stack formed in the first stage of the process;

Fig.s 3 and 4 show a further two perpendicular side views of the stack during the second stage of the process;

Fig.5 shows a side view of the package during the third stage of the process;

Figs. 6 and 7 show sections along lines VI-VI and VII-VII respectively of parts of the package produced in the third stage shown in Fig.5;

Fig.8 shows the operations performed on the package during the fourth stage of the process;

Fig.s 9 and 10 show the operations performed in the fifth stage of the process.

[0008] The process according to the present invention provides for packing stackable items indicated schematically by 1 in the accompanying drawings and usually packed on pall­ets, e.g. sacks of powdered material, building materials or any products which may be stacked one on top of the other.

[0009] As shown schematically in Fig.s 1 and 2, in the first stage of the process, the said items 1 are arranged in the form of a substantially parallelepiped stack 2 wherein at least the bottom layer 3 is narrower than the others, so as to form a pair of steps 4 as shown in Fig.2. Between the said bottom layer 3 and the rest of stack 2, there is placed a sheet 5 of meltable material, the size of the said sheet being slightly greater than that of stack 2 resting on top of it, so as to produce free end portions 5a.

[0010] In the second stage of the process shown in Fig.s 3 and 4, a first strip portion 10 is wound about the four stack surfaces 6, 7, 8 and 9 perpendicular to a first vertical plane, in such a manner as to form a first continuous loop. As shown in Fig.s 1 and 3, the said second stage is conveniently performed by moving stack 2 towards strip 10, which is stretched between two reels 11 and 12 off which the strip material is fed. As stack 2 is moved to­wards strip 10, which may be performed in any appropriate manner, strip 10 is wound about three of the said four surfaces, i.e. surfaces 6, 7 and 9. Application of strip 10 on to the said fourth surface 8 is performed by means of a pair of bars 13 which, as shown in Fig.3, are brought together, commencing from the position shown by the dotted line, so as to exert pressure on surfaces 14 of strip 10 and so feed it off reels 11 and 12 and on to the said sur­face 8 of stack 2.

[0011] The said bars 13 conveniently also provide for sealing and cutting strip 10 for producing the said continuous loop. For this purpose, the said bars 13 may be provided with an internal resistor for heating and so melting lo­calized portions of strips 10, and appropriate means for cutting the same subsequent to sealing. The said sealing operation is performed on both the ends of strip 10 for forming the said continuous loop, and at the same time, on the ends of strip 10 fed off reels 11 and 12 (Fig.1) in preparation for the next stack.

[0012] In the third stage of the process shown in Fig.5, a second strip portion 15 of the same material is wound about the four stack surfaces perpendicular to a second vertical plane perpendicular to the said first vertical plane, so as to form a second continuous loop. The four surfaces about which the said second strip portion 15 is wound are surfaces 7 and 9 (to which the said first strip portion 10 has already been applied) and surfaces 16 and 17 (Fig.5). The said second strip portion 15 is applied as already described in connection with strip portion 10, i.e. by moving stack 2 towards strip 15, as shown in Fig.5. Between the said second and third stages, stack 2 is conveniently turned 90° about its vertical axis or, alternatively, fed at a 90° angle to its previous travel­ing direction, so as to present surfaces 16 and 17 sub­stantially parallel with the plane of strip 15 at the start of the third stage.

[0013] In both the second and third stages, the width of strip portions 10 and 15 is slightly greater than that of sur­faces 6, 7, 8, 9, 16 and 17 about which they are wound, so as to produce overlapping free end portions 17a. At the end of the third stage, therefore, there is formed a stack 2 of items 1 enclosed inside the two continuous loops formed by strip portions 10 and 15. The free ends 17a of strips 10 and 15 overlap as shown in Fig.6 sec­tion, whereas ends 5a of sheet 5 are turned into contact with strip portions 10 and 15. Furthermore, as shown in Fig.7, steps 4 are bridged by strip portions 18 which as yet are detached from surfaces 19 and 20 of steps 4 to produce a cavity 21.

[0014] In the fourth stage shown in Fig.8, the assembly produced in the third stage is heated so as to at least partially melt the material of strips 10 and 15 and sheet 5 and so seal free end portions 5a and 17a. The fourth stage may be performed using the equipment shown in Fig.8, which substantially comprises a number of hot gas generators 25, each supported on one side of a four-sided frame 26, for directing a number of hot gas jets on to assembly 27 consisting of stack 2 of items 1 and the two continuous loops formed from strips 10 and 15, and located in the center of frame 26. Each of the said generators may con­veniently comprise a gas burner 28 and a blower, e.g. cen­trifugal blower, 29. Provision may obviously be made for heating means other than those described herein.

[0015] For heating assembly 27 in the fourth stage, frame 26 may be moved vertically up and down on pillar 30.

[0016] Needless to say, generators 25 may be arranged in any man­ner for directing gas jets on to predetermined portions of assembly 27.

[0017] In the fifth stage of the process shown in Fig.s 9 and 10, hot gas jets 31 are directed on to bridge portions 18, as shown in Fig.9. Such localized heating combined with the pressure of the jet results in permanent deforma­tion of bridge portions 18, which thus adhere to surfaces 19 and 20 of steps 4 as shown in Fig.10. Mechanical thrust means of any type may be provided for improving the grip of bridge portions 18 on surfaces 19 and 20.

[0018] In the sixth stage of the process (not shown), assembly 27 is cooled for shrinking strip portions 10 and 15 and so forming the package. The said cooling stage may be per­formed by simply allowing assembly 27 to cool in air, or using appropriate cooling means for accelerating the pro­cess.

[0019] The nature of the material of strips 10 and 15 is such that, when cooled, it shrinks considerably for firmly binding items 1 of stack 2 inside the said continuous loops.

[0020] The resulting package clearly provides for effective air­tight sealing and protection of items 1 by virtue of all the overlapping end portions of strips 10 and 15 being sealed together. Perforated strips may, however, be em­ployed, should air circulation inside the package be re­quired. Furthermore, the wrapping formed about stack 2 by the said first and second strips 10 and 15 presents substantially the same form as the surfaces defining stack 2. This applies not only to major surfaces 6, 7, 8, 9, 16 and 17, but also to surfaces 19 and 20 of steps 4 which, with the package resting on an appropriate support­ing surface 33, form longitudinal channels 32 (Fig.10) enabling handling of the package by a fork-lift truck in exactly the same way as on a pallet. By virtue of the mechanical resistance provided by the two continuous loops formed by strips 10 and 15, the resulting package may be handled and stored normally with no risk of distortion. Sheet 5 between bottom layer 3 and the rest of stack 2 provides for increasing the mechanical resistance of the assembly, by virtue of free end portions of 5a of sheet 5 being sealed to strips 10 and 15, and sheet 5 itself being firmly sealed to the walls of the package, thus enabling it to resist even severe tensile stress in the sheet 5 plane. For certain applications, however, sufficiently strong packages may be formed using the process according to the present invention, but with no need for sheet 5. The process according to the present invention may obvious­ly be performed on-line in fully automatic manner. Fur­thermore, the equipment required is extremely straightfor­ward and, therefore, low-cost.

[0021] To those skilled in the art it will be clear that changes may be made to the stages in the process as described and illustrated herein without, however, departing from the scope of the present invention.

[0022] For example, the top layer of stack 2 may be narrower than the others, as opposed to bottom layer 3 in the example shown, with no change in the basic stages of the process.

Claims

1) - A process for packing stacked items (1) and enabling handling by a fork-lift truck, characterised by the fact that it comprises at least a first stage consisting in arranging the said items in the form of a substantially parallelepiped stack (2) wherein at least the bottom layer (3) is narrower than the others, so as to form a pair of steps (4), and wherein, between the said bottom layer and the others, there is placed a sheet (5) of a first meltable material, the size of the said sheet being slightly great­er than the stack resting on the same, so as to produce free end portions (5a) of the said sheet; a second stage wherein a first strip (10) of a second heat-shrinkable material is wound about the four surfaces (6, 7, 8, 9) of the said stack perpendicular to a first vertical plane, so as to form a first continuous loop; a third stage wherein a second strip (15) of the said second material is wound about the four surfaces (7, 9, 16, 17) of the said stack perpendicular to a second vertical plane per­pendicular to the said first vertical plane, so as to form a second loop; the width of the said strips being slightly greater than that of the lateral surfaces of the said stack about which they are wound, so as to produce free overlapping strip end portions (17a); a fourth stage wherein the assembly so formed is heated, so as to at least partially melt the said strip and sheet material and so seal the said free ends of the same; a fifth stage wherein the said strip portions (18) overlapping the said steps (4) are deformed permanently in such a manner as to adhere to the surfaces (19, 20) of the same; and a sixth stage wherein the assembly so formed is cooled for shrinking the said material and so forming the package.

2) - A process as claimed in Claim 1, characterised by the fact that the said fifth stage is performed by direct­ing hot gas jets on to the said portions of the said strips.

3) - A process as claimed in Claim 1, characterised by the fact that the said fifth stage is performed using mechanical thrust means for exerting predetermined press­ures on the said strip portions.

4) - A process as claimed in one of the foregoing Claims, characterised by the fact that the said second and third stages are performed by moving the said stack towards a strip (10) of the said second material stretched between two reels (11, 12) off which the said strip (10) is fed and wound about three (6, 7, 9) of the said four surfaces of the said stack, and by applying the said strip (10) on to the said fourth surface (8) of the said stack by means of a pair of bars (13) which are brought together so as to apply pressure on a surface (14) of the said strip (10) and so feed it off the said reels (11, 12).

5) - A process as claimed in Claim 4, characterised by the fact that the said bars (13) also provide for sealing and cutting the said strip for producing the said first and second continuous loops; said sealing operation also providing for sealing the free ends of the strips fed off the said reels.

6) - A process as claimed in one of the foregoing Claims, characterised by the fact that, between the said second and third stages, the said stack is turned 90° about its vertical axis.

7) - A process as claimed in one of the foregoing Claims, characterised by the fact that the said fourth stage is performed by directing a number of hot gas jets on to the said assembly.

8) - A process as claimed in Claim 7, characterised by the fact that the said jets are produced by means of a first set of hot gas generators (25); and that, during the said fourth stage, the said generators are moved in relation to the said assembly for directing the said jets on to the said surfaces of the same.

9) - A process as claimed in one of the foregoing Claims, characterised by the fact that the said fifth stage is performed by directing hot gas jets from a second set of hot gas generators on to the strip portions (18) overlap­ping the said step (4).

10) - A process as claimed in Claim 8 or 9, characterised by the fact that the generators in the said first set are supported on a four-sided frame (26) enclosing the said assembly (27) and designed to move vertically on a sup­porting pillar (30); and that the said generators in the said second set are located beneath the surface (33) sup­porting the said assembly (27).

Drawing