RU2376224C2 - Cardboard tray - Google Patents

Abstract

FIELD: packing industry. ^ SUBSTANCE: method for making of leg for tray includes the following stages: cutting of slots in side surface of polygonal cardboard pipe for cutting of stiffening walls, creases are made by impression in side surface of cardboard pipe for folding of stiffening walls, stiffening walls are folded to separate bearing sections of leg into chambers. Grooves are arranged in side surface of cardboard pipe. Grooves pass parallel to desired direction of loading. Cutting of slots, impression of creases and grooves making is realised simultaneously. Installation for making of tray legs comprises the following components: pipe processing machine for cutting of slots and impression of creases in side surface of polygonal cardboard pipe. Installation also comprises folding machine for folding of stiffening walls along creases and creation of bearing sections of tray leg. ^ EFFECT: easier manufacturing, transportation and higher stability, protection against moisture. ^ 16 cl, 33 dwg

Description

The present invention relates to the field of transport pallets serving for the transport of goods. Pallets are used so that transported goods can be loaded, for example, with forklifts.

In the prior art, various possibilities are known for replacing standard wood pallets with pallets of cardboard material. Cardboard pallets have the advantage that the recipient can send them for recycling. Also, due to their low weight, such pallets are increasingly used since they are lighter than wooden pallets and, therefore, are associated with lower transportation costs.

From the utility model DE 20103902 U1, a pallet made of smooth cardboard or corrugated cardboard is known having legs, which consist of several runners running parallel and at a distance from each other, made in one piece with the upper plane. When folded, the runners have a triangular or quadrangular section.

From DE 19523492 A1, a pallet is known in which cores from paper, carpet rolls or rolls of similar materials are used as load-bearing elements, wherein the roll cores are arranged in two layers on top of each other and perpendicular to each other.

Finally, a pallet system consisting of a flat upper plane provided with tubular skids is known from WO 95/25672. Skids are folded from flat cardboard. To reinforce the runners, separate rectangular reinforcing elements are placed in them, consisting, for example, of wound or cellular cardboard material.

Cardboard pallets from the prior art have various disadvantages due to their low strength or stability, manufacturing complexity, material consumption and large transport volume for sending the pallet itself. In addition, well-known cardboard pallets are susceptible to water and moisture due to the capillary action of the cardboard material.

Therefore, there is a need for a pallet that would be easier to manufacture, would have higher stability, would require less or cheaper material, would be better protected from moisture and water, and would be easier to transport itself. In addition, there is a need for a method for manufacturing such a pallet and an apparatus for manufacturing such pallets.

The above problems are solved, and the above requirements are satisfied by means of the foot for the pallet according to claim 1, the pallet according to claim 11, the method for manufacturing the legs of the pallet according to 14, the installation for the manufacture of legs of pallets according to claim 21, and the method for manufacturing the pallet according to claim 32.

The aforementioned problems, in particular, are solved by means of a pallet leg containing a cardboard tube of polygonal cross section, the cardboard tube having open sections providing a transverse passage through the pallet legs and closed bearing sections, each of the closed bearing sections being divided by stiffness walls into several chambers wherein the stiffening walls are formed by the side walls of the cardboard pipe folded inward.

Such a pallet leg can be made quickly and simply from a polygonal cardboard tube. Since the source material is a pipe that only needs to be processed, it is not necessary to manufacture and assemble additional cardboard elements. The reinforcements of the bearing sections are formed only by the cardboard material available in the cardboard tube. This ensures a completely waste-free production of pallet legs. The tubular starting material is also particularly stable, since it does not have bonding spots, obvious seams, etc., and it is preferably wound in one piece. In addition, due to the separation of the bearing sections by the stiffening walls, a stable and, on the other hand, very light structure, stable even under high loads, appears.

In one preferred embodiment, the cardboard tube consists of wound layers of paper or wound layers of recycled paper. By winding the paper layers, a particularly high strength is achieved, even when using recycled paper. The use of recycled paper reduces material costs.

Cardboard and paper mills have machines of a fixed working width, so that by the production of paper or cardboard of a certain width, side cloths constantly accumulate. With mass changes, transitional webs also arise, which also accumulate as waste. These secondary or transitional webs are usually sent back for recycling. This is associated with high costs for the paper mill, as rolls of side and transition sheets are too compact for direct processing. Therefore, they are unwound or sawed at high cost.

Since only narrow paper or cardboard strips with a width of 70-140 mm are required for winding cardboard tubes according to the invention, side and transitional webs that accumulate in the production of paper in the form of waste can easily be directed to appropriate use. Wider side and transitional webs should be cut into strips of the required width, which is possible without problems in a paper mill. Since by-products are almost non-sellable goods, they can be purchased very cheaply, if not for nothing, which significantly reduces the cost of material on the legs of pallets.

Preferably, the cardboard tube has a quadrangular or octagonal cross-sectional shape. Due to this shape, the leg of the pallet forms an even supporting surface for the upper plane of the pallet and a flat surface of contact with the floor, so that the resulting loads can be distributed over a large area.

In another preferred embodiment, the cardboard tube consists of a cardboard material reinforced with liquid glass. Hardening a cardboard tube with liquid glass gives the cardboard tube made from it a particularly high strength. In addition, liquid glass as a hardening or adhesive material is very cheap, since its cost is about 1/3 of commonly used adhesives. Additionally, liquid glass does not emit toxic fumes when cured in air. Additionally, the cardboard tube after hardening is protected from water and moisture, so that the pallet can also be used outdoors.

Preferably, the closed portions of the legs of the pallet have side walls provided with grooves extending substantially parallel to the load direction. Grooves or corrugations strengthen the side walls of the bearing sections in comparison with a flat surface and increase the strength in longitudinal bending. The grooves can also turn into each other, resulting in a wavy shape.

Preferably, the closed areas are divided into three or four chambers, respectively. Further, the individual chambers of the closed areas are preferably of the same shape. The shape and number of chambers to a decisive extent determine the stability of the pallet. Advantageously, the closed chambers can, in addition to compressive forces due to the weight of the load, also absorb transverse forces, which often arise during transportation and loading of the pallet.

In another preferred embodiment, the stiffening walls are folded along beams extending parallel to the load direction. Bigi facilitate accurate folding of the stiffness walls. Since the bigi extend in the direction of the load, the stiffening walls stand vertically inside the bearing sections and therefore transmit the arising compressive forces to the floor surface in the direction of the main load.

Preferably, the stiffening walls of the closed portion are superficially glued together. The bonding of the stiffening walls significantly increases the bearing capacity of the bearing sections, since the bonding places can transmit shear forces between the stiffening walls.

Preferably, the cardboard tube has solid upper and lower walls, the side walls folded inwardly glued to the upper and lower walls. The solid upper and lower walls of the pallet foot serve as spacing elements and reinforcements of the bearing sections.

Further, it is preferable that the closed sections have at least one side window for connecting the legs of the pallet with a transverse brace.

In particular, the aforementioned problems are also solved by means of a pallet containing a substantially flat, even upper plane and at least two legs according to any one of paragraphs. 1-11. By adding a suitable upper plane, such as wood, metal or cardboard, together with the legs, a complete pallet is obtained, which is adapted to the specific application.

Preferably, the upper plane also consists of cardboard or recycled cardboard. Thus, a completely recyclable cardboard pallet was created.

In another preferred embodiment, the legs of the pallet are glued to the upper plane parallel to each other.

Preferably, the pallet further comprises at least one transverse brace connected to the legs of the pallet and extending perpendicular to them. Due to this transverse brace, the stability of the pallet is maximally increased, so that the thickness of the material of the upper plane can be reduced. For example, the thickness of a relatively expensive upper plane with the same bearing capacity can be reduced by about 50%. Due to this, a cost reduction of up to 20% is achieved.

The cross brace can, if necessary, be used or not used, so that an individually configurable pallet system is created.

Preferably, the transverse brace is made of the same cardboard pipe as the legs of the pallet. Thus, the same machine for winding cardboard tubes can be used.

Further, the above-mentioned problems are also solved by a method of manufacturing a leg for a pallet, comprising the following steps:

1. Cutting out slots in the lateral surface of a cardboard pipe for cutting stiffness walls;

2. Big embossing in the lateral surface of a cardboard pipe for folding stiffening walls;

3. Folding the stiffness walls to separate the bearing sections of the pallet leg into the chambers.

Thanks to the method according to the invention, the advantages described above with respect to the legs of the pallet are also achieved.

In one preferred embodiment, the method further includes the following steps carried out before other steps:

1. Winding endless cardboard pipe from paper or cardboard layers;

2. Cutting the endless cardboard pipe to the desired length to form a separate cardboard pipe.

Thus, in a manner based on a paper source material, a pallet leg of a certain length and a certain strength and bearing capacity is made. The winding stage can be varied to obtain different wall thicknesses of the cardboard tube and, due to this, also different bearing capacity of the pallet leg.

Preferably, the method further includes the step of making grooves in the lateral surface of the cardboard tube, the grooves extending substantially parallel to the desired direction of loading. Grooves or corrugations reinforce the lateral surface of the cardboard pipe.

Preferably, the steps of cutting down the slots, embossing the bigs and making the grooves are carried out simultaneously. Thus, the manufacturing time of the pallet leg is reduced.

In another preferred embodiment, the method further includes the step of impregnating the cardboard tube with liquid glass. Preferably, the paper strip from which the cardboard tube is wound is passed through an adhesive unit, with one side of the paper strip spreading over the entire surface with liquid glass. The use of water glass as an adhesive and hardening agent is possible only because immediately after the winding process a pressing, embossing and die-cutting process is carried out. Due to the pressing of the pipe, absolute bonding is achieved, which with traditional winding is achieved only through costly additional processing using high-quality adhesives. In particular, the winding of a cardboard pipe can occur at a significantly higher speed than in traditional methods, since possible air bubbles between the glued paper webs are extruded by pressing the pipe.

In another preferred embodiment, the method includes the step of pressing and heating the cardboard tube to harden it without bubbles. Preferably, the pressing and heating step is carried out simultaneously with the cutting and embossing step. When pressed, the fibers of the cardboard are preserved, and the surface of the cardboard is smoothed, as a result of which the leg of the pallet has less moisture absorption. Further, due to heating, the drying time of the pallet legs is reduced so that immediate further processing can be carried out. With normal drying, it would take up to 2 weeks.

Preferably, the method includes the step of applying adhesives to portions of the stiffening walls to adhere the latter to each other.

Further, the aforementioned problems are also solved by means of a pallet leg making apparatus comprising a processing machine for cutting slots and embossing bigs in the side surface of a polygonal cardboard tube and a folding machine for folding stiffening walls along the big and forming bearing sections of the pallet leg.

Thanks to this installation, the legs of the pallet can be made of cardboard tubes quickly and cost-effectively. The installation can work fully automatically, so that a large number of pallet legs can be produced at low cost per unit of production.

Preferably, the apparatus further comprises a winding machine for manufacturing an endless cardboard pipe and a cutting device for cutting an endless cardboard pipe in order to obtain a cardboard pipe of the desired length.

In another preferred embodiment, the processing machine comprises an internal tool that can be inserted into the cardboard tube with the possibility of its radial expansion and fit to the inner wall of the cardboard tube.

Preferably, the inner tool has interchangeable machining surfaces for creasing, embossing, and punching or cutting. The machining surfaces of the internal tool can thus be easily replaced during wear.

Preferably, the inner tool may comprise at least one electric heating element. Due to the electric heating element, the inner tool can be heated to facilitate the solidification of the soaked liquid glass and, thus, the wet cardboard tube. A cardboard tube is thus “baked” or pressed in a mold.

In another preferred embodiment, the processing machine comprises external tools that include interchangeable die cutting tools for cutting openings in the side surface of the cardboard pipe and interchangeable embossing tools for embossing the bigs in the side surface of the cardboard pipe. Due to the interaction of external and internal tools, the cardboard tube is compressed so that air is squeezed out between the paper layers of the cardboard tube and optimal adhesion of the paper webs is achieved.

Preferably, the external tool further comprises interchangeable embossing tools for making grooves.

Further, it is preferable that the installation includes an edge trimmer for cutting longitudinal slots in the side surface of the cardboard tube.

Preferably, the folding machine comprises vacuum suction cups for bending stiffening walls from the side surface of the cardboard tube to the outside. Vacuum suction cups are placed on the cut-out sections of the side walls of the cardboard pipe and a vacuum is applied so that the stiffness walls can be captured and simply bent outward.

Preferably, the folding machine comprises rotary grippers driven by an electric motor for folding the stiffening walls into the supporting sections of the cardboard tube. After bending the stiffening walls by means of vacuum suction cups, rotary grippers can be used to fold the stiffening walls back into their desired shape.

Preferably, the rotary grips are rotatable by means of stepper motors and pneumatic movement up and down.

The problem of taking up a lot of space for transporting the finished pallet is solved by the method of manufacturing the pallet, which includes the following steps in the following sequence:

1. The formation of preforms from a polygonal cardboard pipe;

2. Sending preforms to end users;

3. Fastening the preforms on a suitable upper plane by the end user.

Since the last step of the method is carried out only by the end user, a relatively bulky pallet arises only at this moment. Preforms take up little space when sending to the end consumer, so shipping costs are low. A truck can usually accept 800 empty pallets corresponding to the largest Euro pallets. When sending preforms in a truck, about 8,000 individual systems can be transported, which the end user then collects on site.

Preferably, the preforms are the legs of the pallets or the transverse braces, then the final consumer needs to decide which upper plane to use for him - from wood, plastic or cardboard. Further, depending on the transported cargo, he has freedom with respect to the number of preforms required. For example, instead of three legs for light loads, only two legs per pallet can be used, which means material savings of about 30% per pallet. The final consumer can further decide, depending on the load, whether he should use lateral braces or not.

In another preferred embodiment, the method includes the step of delivering the upper plane to the final consumer. Thus, the end user receives a complete set of pallets.

Preferably, the pallet according to the invention, with the same dimensions, has its own weight of about 3.5 kg compared with a wood pallet of about 11 kg. Therefore, women can also handle these pallets. In addition, gas processing prescribed for export supplies may disappear, resulting in a further reduction in production costs.

Below are described drawings depicting preferred embodiments of the present invention. In the drawings represent:

- figure 1: the pallet according to the invention in three dimensions in a first preferred embodiment with legs according to the invention;

- figure 2: two side views of a preferred embodiment of the legs, and the upper side view shows the bigi, and the lower one is the slots;

- figa-3E: horizontal sections of the bearing sections of the preferred legs of the pallet, and shown various options for folding the stiffness walls;

- figure 4: a horizontal section of a pipe processing machine for processing cardboard pipes;

- figure 5: cross section of the external tool of the preferred pipe processing machine;

- Fig.6: three-dimensional view of an external tool;

- Fig.7: a longitudinal section of an internal tool of a preferred pipe processing machine;

- Fig: axial cross section of a preferred cardboard pipe and the inner tool of the preferred pipe processing machine;

- Fig.9: a cross section of a section of a pipe processing machine showing a cardboard pipe, external tools, an internal tool and a trimming device;

- figure 10: three-dimensional view of a cardboard pipe with an internal tool and a preferred edge trimmer;

- 11: at the top is a top view of a folding tool of a folding machine, and below is a side view of a folding tool and a stiffening wall of a cardboard pipe;

- Fig: rotary capture in contact with the stiffness wall;

- Fig: side view and eight top views of a preferred embodiment of the legs of the pallet to explain the process of folding the stiffness walls;

- Fig: view of a preferred embodiment of the installation for the manufacture of legs of the pallet;

- Fig.15: side view of the installation of Fig.14;

- Fig.16: the second embodiment of the pallet, side view, and in addition to the legs of the pallet also used transverse braces;

- Fig: top view of the assembly diagram of the pallet, which uses three legs and six transverse braces;

- Fig. 18: side view of a cardboard pipe equipped with big and slots;

- Fig: end section of the transverse brace in three-dimensional form;

- FIG. 20: cross section of a cross brace.

Below with reference to the drawings, preferred embodiments of the present invention are described in detail.

Figure 1 shows the pallet 1, consisting of a substantially flat, even upper plane 50 and three legs 10, preferably mounted under the upper plane 50. Three legs 10 are preferably used, the legs 10 being parallel to each other. Two legs are fixed on the edge of the upper plane 50, and one leg 10 is fixed in the middle of the upper plane 50. The fixing can be carried out in various ways, however, it is preferable to glue the legs 10 to the upper plane 50.

Depending on the application of the pallet 1 and the maximum load, only two legs or more than three legs can also be used.

The legs 10 consist essentially of a solid cardboard tube 11 of a polygonal section. In Fig.1 shows a cardboard pipe 11 of a square section, and Fig.8-15 - an octagonal section. Of course, six or more carbon sections are also possible, however, however, the contact surfaces of the legs 10 to the upper plane 50 must be even so that the legs can be firmly glued to the upper plane 50.

Leg 10 in FIG. 1 has three closed bearing sections 30, preferably rectangular in shape, and two open sections 20 between the bearing sections 30. The open sections form a transversal, i.e. transverse, passage through the legs, so that the pallet can also be taken in the transverse direction with a fork of a forklift truck.

The leg 10 has a continuous upper wall 16, with which the leg 10 is glued to the upper plane 50, and a solid lower wall 14, which connects the bearing sections 30 at a distance from each other, increasing the stability of the legs 10.

Each leg 10 is made of a cardboard tube 11 of a polygonal section, which can be a specially wound cardboard tube or a cardboard tube that occurs as a waste in the manufacture of paper or cardboard. Preferably, recycled or waste paper of side sheets or transitions is used for winding the cardboard tube, which can preferably be impregnated or covered with liquid glass before winding to give the subsequent leg 10 increased strength.

Water glass is commercially available as potassium water glass (potassium silicate K ₂ SiO ₃ ) or as sodium water glass (sodium silicate Na ₂ SiO ₃ ) and is a syrupy solution of sodium silicate or potassium silicate in water. Liquid glass is cured in air and serves as an inorganic binder, which gives the cardboard tube 11 and leg 10 increased strength and moisture resistance. Liquid glass is used as a component for bonding, hardening and moisture protection of the legs of the pallet. Moisture protection can be further enhanced if the legs of the pallet are immersed in liquid glass 20-30 mm from their lower side or completely. Due to the accuracy of cutting, liquid glass cannot penetrate into the bearing sections 30.

Figure 2 shows how the cardboard tube 11 is equipped with bigs 36 and slots 38 for making legs 10. The top view of figure 2 shows the side wall of the polygonal cardboard tube 11 with subsequently bearing sections 30 and stiffening walls 32, folded from the side wall cardboard pipe 11. Next, a top view in FIG. 2 shows the bigi 36 indicated by dashed lines made in the cardboard pipe 11 to facilitate folding of the stiffening walls 32 along these bigi 36.

The bottom view in figure 2 shows the slots 38, necessary for cutting or cutting walls 32 of rigidity from the side walls of the cardboard pipe 11.

In order to strengthen the bearing sections 30 of each leg 10 and to increase its bearing capacity, the sections of the side walls of the cardboard pipe 11 are folded into the bearing sections 30 as walls 32 of stiffness. As a result, several chambers 34 respectively appear inside the pipe in the region of the bearing sections 30.

Preferred examples of the shape of such chambers 34 and preferred folding patterns are shown in FIGS. 3A-3E. They show horizontal sections of the bearing section 30. The surface-interlocking sections of the stiffening walls 32 are preferably glued together, which significantly enhances the reinforcing effect. For gluing the walls 32 of stiffness between each other and with the upper 16, lower 14 and side walls 17 of the legs can be used conventional adhesive for paper, hot melt adhesive, etc. Preferably, liquid glass is also used for this.

The gap between the stiffening walls 32 shown in FIGS. 3A-3E serves only to explain the corresponding folding pattern and is actually not visible or not so noticeable.

Figure 3 shows the first folding option, in which the stiffening walls 32 are folded inwards along the three bigs 36, forming a cross-shaped stiffness structure inside the closed section 30, the stiffening walls passing along the symmetry lines of the closed section 30. Due to this, the closed section in Fig. 3A divided into four chambers 34, essentially the same size.

FIG. 3B also shows the crosswise arrangement of the stiffening walls 32, however, however, one stiffening wall is not double.

On figs shows a variant in which two oblong chambers are formed, and one chamber is partially divided in the middle by the stiffening walls.

3D shows a variant in which the stiffening walls 32 form three closed chambers 34 located in the longitudinal direction of the legs 10. This embodiment, due to the large overlapping portions of the stiffening walls 32, provides a very good reinforcing effect.

The same applies to the embodiment of FIG. 3E, moreover, by bending the two ends of the stiffness walls 32 to the side wall, more uniform reinforcement of the bearing sections 30 occurs.

Of course, other folding patterns are possible, as the cut-out side walls 32 of the cardboard pipe 11 can be bent inside the bearing sections 30 to form several chambers 34.

Figure 4 shows a horizontal section of a processing machine 110 for a pipe. In this embodiment, the machine 110 consists of two internal tools 111 and two external tools 114, which by means of hydraulic cylinders 130 can be moved in the direction of the internal tools 111 for pressing, embossing, creasing and cutting of the cardboard pipe 11. The internal tools 111 are introduced laterally into the pipe 11 and by means of two pressure cylinders 140 open. After expansion, the inner wall 18 of the cardboard tube 11 abuts against the outer side of the inner tool 111.

Figure 5 shows a detail of the external tool 114 and two pressure cylinders 130. In Fig.6, the external tool 114 is shown in three-dimensional form. Figures 5 and 6 show that the actual tools 115, 116, 117 of the external tool 114 are made of elongated profiled elements screwed to a solid carrier plate. Thus, the tools 115, 116, 117 of the external tool 114 are made, if necessary, with the possibility of replacement.

The external tool 114 comprises cutting tools 115 for making slots 38 in the lateral surface of the cardboard pipe 11, embossing tools 116 for making bigs in the lateral surface of the cardboard pipe 11, and embossing tools 117 for making grooves 39 to reinforce the lateral surface of the cardboard pipe 11. Embossing tools 117 preferably rounded on its machining surface, so that a slight undulation of the lateral surface of the cardboard tube 11 occurs, but sharp edges are not formed that could to rampage over the break.

7 is a longitudinal sectional view of an inner tool 111, explaining how a cardboard tube 11 can be radially expanded in the tool 111. To this end, the inner tool 111 comprises a pressure cylinder 140 that moves the wedge-shaped element 141 configured to enter between two also wedge-shaped elements 142. During this entry process, the wedge-shaped elements 142 diverge in parallel. The expansion of the inner tool 111 is limited by two stops 143, so that the cardboard tube 11 only tightly pulls on the inner tool, but does not break.

On Fig shows a cross section of the inner tool 111 and the cardboard pipe 11. In particular, Fig.8 shows the electric heating elements 113, which provide heating of the inner tool. Thus, the hardening process of the cardboard tube soaked with liquid glass can be accelerated or even completely completed. The cardboard pipe 11 is “baked” in a machine 110 at a temperature of 80-120 ° C. In this case, air possibly enclosed between the paper layers is squeezed out. In addition, FIG. 8 shows interchangeable machining surfaces 112 corresponding to the machining tools 115, 116, 117 of the outer tool 114. The machining surfaces 112 can also be replaced if necessary.

Fig. 9 shows a cross-section of a pipe-processing machine 110, four external tools 114 being used here, so that all four sides of the cardboard pipe 11 can be machined. To make longitudinal slots for the walls of rigidity, the machine is equipped with cutting tools 118 that run longitudinal pipes in the cardboard pipe 11 cut through the walls 32 stiffness.

Figure 10 shows a three-dimensional view of an example of a cutting tool 118, and it can be moved in the direction of the inner tool 111 by means of two pressure cylinders 130. Next, figure 10 shows another variant of the grooves 39 S-shaped. The slot 38 obtained by the cutting tool 118 is also shown symbolically.

In the process of embossing, the solid upper 16 and lower 14 walls also acquire embossing (not shown), which increases the stability of both walls, in particular from deflection. Due to embossing, the walls 32 of the stiffness are fixed from the inside and possibly do not require bonding with each other. In addition, the support surface of the leg 10 on the cover plate 50 is reduced, as a result of which better adhesion can be achieved due to the higher pressing force. In this case, glue consumption can be reduced.

Additionally, due to such embossing, the surface of the support on the floor is reduced, so that moisture absorption is further reduced. In addition, damage to the pallet is prevented when picked up by a loader, since its wheels are sent to the provided free spaces due to the convexity of the cardboard wall. This embodiment also provides the use of a pallet in automatic transport paths, as well as storage and retrieval in automatic multi-tier warehouses.

11, a top view is shown at the top and a bottom view of a folding device 127 of a folding machine 120 for folding stiffening walls 32 is shown. The folding machine 120 comprises folding devices according to the number of stiffness walls 32. In the exemplary embodiment described herein, these are twelve folding devices 127.

The folding device 127 consists of two rotary grippers 122, 123, also shown in detail in FIG. 12. The rotary grippers 122, 123 can be mounted on the edge of the stiffening wall 32 to fold the stiffening wall 32 along its bigs 36. To do this, the rotary grips 122, 123 are installed with the possibility of pneumatic movement up and down to grasp the edge of the stiffness wall 32.

The folding device 127 further comprises two memory stepper motors 124, 125, which rotate the rotary grippers 122, 123. The left stepper motor 124 rotates the entire folding device 127, and the right 125 rotates the rotary disk 126, which contains the rotary grab 123 and appropriate pneumatics for moving up and down.

Using such folding devices 127 and vacuum suction cups 121, the folding process of all the walls 32 of the stiffness of the foot 10 of the pallet proceeds automatically and simultaneously. The folding process as an example is shown in FIG. 13 in steps 2-8.

At the very top of FIG. 13, again, as an example, a cardboard tube 11 cut out and provided with bigi 38 is shown. Steps 1-8 are shown in a plan view.

Before the folding process, glue is applied to the bonded sections of the stiffening walls 32.

In step 1, suction cups 121 are applied to the cut-out side walls 32 of the cardboard pipe 11 and a vacuum is created to suck the side walls 32. In step 2, the suction cups 121 are turned outward and the stiffening walls 32 are folded outward, i.e. from the cardboard pipe 11. In step 3, the rotary grippers 122, 123 are put on the edges of the stiffening walls 32 and the rotary grippers 122, 123 are pneumatically moved down. The pivoting grips are indicated in FIG. 13 by black or white circles. At the same time remove the suction cups 121 and eliminate the vacuum.

In step 4, the outer rotary grips 122 are rotated, resulting in a first folding along the first big 36. In step 5, the outer rotary grippers are deleted, i.e. move up, and rotate the middle rotary grips, if you wish to carry out the second folding.

In step 6, all swing captures are removed by pneumatically lifting them. In step 7, the stiffening walls 32 are automatically folded by means of a folding device inside the bearing sections 30 due to external pressure, as indicated by arrows.

Finally, in step 8, the remaining tabs 37 are folded down and up and glued to the stiffening walls 32.

On Fig shows a top view of the installation 100 for the manufacture of legs 10 of the pallet. Installation 100 includes a winding machine 150, which winds the winding paper 13 into an endless cardboard tube 12 of a polygonal section. Preferably, the endless cardboard tube 12, and thus also the cardboard tube 11, has 5-20 layers of paper depending on the required load bearing capacity of the leg 10. Thus, a wall thickness of 3-5 mm is obtained, which, thanks to a special manufacturing method, can be thinner than traditionally made cardboard tubes having at the same strength a wall thickness of 12-15 mm. The wrapping paper of the endless cardboard tube before winding by means of the glue-aggregate unit in the winding machine 150 is coated on one side with liquid glass.

The endless cardboard tube 12 is discharged from the winding machine 150 and cut into cardboard tubes 11 of the desired length using a cutting device 160. The preferred length of the cardboard pipe is 11 1.4 m.

After cutting, the cardboard tube 11 falls on the first belt conveyor 170. From there, it is transported to the second belt conveyor 180, as indicated by arrows. The second belt conveyor transports the cardboard tube 11 to the respective processing lines. On Fig, only the first processing line is fully shown, and the second is only indicated, however, other processing lines can also be attached at the top.

At the height of the first processing line, the cardboard tube 11 is transferred from the second belt conveyor 180 to the pipe receiver 200 by means of the ejector 185. When the receiver 200 overflows, cardboard tubes 11 at the end of the conveyor belt 180 are placed in a store (not shown). Cardboard tubes 11, if necessary, can be transferred again from the additional drive 190 to the second belt conveyor 180.

From the drive 200, the cardboard tubes 11 are seized by a suction cup with the first transport sprocket 210 and transferred to the pipe processing machine 110. For this purpose, the transport sprocket 210 moves up and rotates 180 °. The vacuum is then removed, and the cardboard tube 11 falls into the pipe processing machine 110. After that, the transport sprocket 210 again returns to its original position.

In the pipe-processing machine 110, the processing of the cardboard pipe 11 begins. The six pressure cylinders 130 on the right and left move to the locked position, the cardboard pipe 11 being only slightly held but not compressed. Then, internal tools 111 are gradually introduced into the cardboard tube 11 by means of toothed conveyors 145. At the same time, the upper pressure cylinder 135 (FIG. 15) is gradually lowered down on the other toothed conveyor 146. The toothed conveyors 145, 146 are blocked to exert sufficient response force for the respective pressure cylinders 140, 135. The pressure cylinders 130, 135, 140 are hydraulically or pneumatically pressurized and move to the operating position. In this position, in the lateral surface of the cardboard tube 11, all bigi 36, slots 38 and grooves 39 are simultaneously executed. At the same time, the material of the cardboard tube 11 is compressed so strongly that air is squeezed between the paper webs. Then or pre-activate the electric heating elements 113 of the inner tool 111, as a result of which the latter is heated, and the cardboard tube 11 is dried and thereby hardens.

After the cardboard tube 11 has hardened or after partial hardening, the pressure cylinders 130, 135, 140 and the gear conveyors 145, 146 are returned to their original position.

The cardboard tube finally cut and equipped with bigamia 36 and grooves 39 is transferred from the pipe processing machine 110 to the folding machine 120 by means of a second transport sprocket 220. The necessary folding processes are carried out on it, as described in detail above.

The legs 10 of the pallet are now ready, and they are sent through a third conveyor belt connecting all the available processing lines to a drive (not shown).

Then the legs 10 can be glued with a suitable upper plane 50 into the pallet 1. It is preferable, however, to carry out this last installation step not directly after the manufacture of the legs 10, but only at the end user. For this, the finished legs 10 are sent to the final consumer separately from the upper planes 50. The final consumer can then carry out the final installation (gluing, joining, stitching, etc.). Thus, transport volume is minimized, and transport costs for sending a pallet are minimized.

Of course, the pallets can also be finally mounted directly by the manufacturer of the legs 10 if the end user does not want to carry out the installation.

On Fig shows another preferred embodiment of the pallet 1. In this embodiment, between the legs 10 are inserted transverse braces 300, further increasing the stability of the pallet 1.

The transverse braces 300 consist, like the legs 10, of a wound cardboard pipe 11. The desired cardboard pipe can be made on the same winding machine 150 as the pipe 11 for the legs 10. Of the cardboard pipe 11 of the desired length by cutting, creasing and embossing can be made respectively two transverse braces 300.

On Fig shows a side view of a cardboard pipe 11 with embossed, longitudinally extending bigy 304 and cut openings 302. Slots 302 divide the cardboard pipe 11 into the upper 305 and lower 306 halves, forming transverse braces 300. When cutting openings 302, the ends of the cardboard pipe are simultaneously cut. (not shown) for the subsequent formation of the pins 310 shown in Fig. 19.

As shown in cross section in FIG. 20, the side surfaces of the cardboard tube halves 305, 306 are folded inwardly along the bigs 304, doubling the thickness of the side walls of the U-shaped transverse brace 300. Then, trunnions 310 are formed at the ends of the transverse braces 300, bending double outwards side walls.

To connect the legs 10 with the transverse braces 300 legs 10 are provided on their bearing sections 30 with side windows 22, which are also cut down (Fig. 16). When assembling the pallet with transverse braces 300, the trunnion 310 is inserted into the side windows 22 of the legs 10 and, if necessary, glued with liquid glass. In this case, the open side of the U-shaped transverse brace 300 points upward in the direction of the upper plane 50 and is adjacent to it with its upper edge.

The manufacture of transverse braces 300 is carried out similarly to the manufacture of legs 10 in an appropriate installation. The transverse braces 300 by means of a processing machine 110 are also pressed, cut, scored and grooved in one operation, if desired. Then, on the folding machine 120, folding of the side walls and trunnions 310 is carried out.

List of Reference Items

1 - pallet

10 - pallet leg

11 - cardboard tube

12 - endless cardboard tube

13 - paper layers

14 - bottom wall

16 - upper wall

17 - side wall

18 - inner wall

20 - open sections of a cardboard pipe

22 - side window

30 - closed bearing sections of the cardboard pipe

32 - stiffening walls

34 - cameras

36 - bigi

38 - slots

39 - grooves

50 - top plane

100 - installation

110 - pipe processing machine for cardboard pipes

111 - internal tool

112 - machining surfaces

113 - electric heating element

114 - external tools

115 - cutting tools

116 - big embossing tools

117 - groove embossing tools

118 - edge trimmer

120 - folding machine

121 - vacuum suction cups

122 - rotary captures

127 - folding device

130 - pressure cylinder

135 - pressure cylinder

140 - pressure cylinder

141 - wedge-shaped inner element

142 - wedge-shaped outer element

143 - emphasis

145 - gear conveyor

146 - gear conveyor

150 - a winding machine for winding cardboard pipes

160 - cutting device

170 - first belt conveyor

180 - second belt conveyor

185 - ejector

190 - second stacker of cardboard tubes

200 - first cardboard tube stacker

210 - first transport sprocket

220 - second transport sprocket

230 - third belt conveyor

300 - cross brace

302 - slot

304 - Bigi

305-upper half

306 - lower half

310 - axle

Claims (16)

1. A method of manufacturing a leg (10) for a pallet (1), comprising the following steps:
cut the slots (38) in the lateral surface of the polygonal cardboard pipe (11) to cut out the stiffness walls (32),
embossing is performed on the bigi (36) in the lateral surface of the cardboard pipe (11) for folding the stiffness walls (32)
folding the stiffness walls (32) to separate the bearing sections (30) of the legs (10) into the chambers (34),
grooves (39) are formed in the lateral surface of the cardboard tube (11), the grooves (39) extending substantially parallel to the desired direction of loading,
cutting of slots (38), embossing of bigs (36) and grooves (39) are carried out simultaneously. 2. The method according to claim 1, further comprising the following steps carried out before other steps:
wrap endless cardboard tube (12) from paper or cardboard layers,
cut the endless cardboard tube (12) to the desired length to form a separate cardboard tube (11). 3. The method according to claim 1, wherein the cardboard tube (11) is impregnated with liquid glass. 4. The method according to claim 3, in which the cardboard tube (11) for its solidification without bubbles is pressed and heated. 5. The method according to claim 1, in which glue is applied to sections of the walls (32) of rigidity for gluing the latter together. 6. Installation (100) for the manufacture of legs (10) of the pallet, containing:
a) a pipe processing machine (100) for cutting slots (38) and embossing bigs (36) in the lateral surface of a polygonal cardboard pipe (11),
b) folding machine (120) for folding the walls (32) of stiffness along the bigs (36) and the formation of bearing sections (30) of the leg (10) of the pallet. 7. Installation according to claim 6, which further comprises:
a) a winding machine (150) for the manufacture of an endless cardboard pipe (12),
b) a cutting device (160) for cutting an endless cardboard pipe (12) in order to obtain a cardboard pipe (11) of the desired length. 8. Installation according to claim 6 or 7, in which the pipe-processing machine (110) contains an internal tool (111) for insertion into the cardboard pipe (11) with the possibility of its radial expansion and fit to the inner wall (18) of the cardboard pipe (11). 9. The apparatus of claim 8, wherein the inner tool (111) has interchangeable machining surfaces (112) for creasing, embossing, or punching. 10. Installation according to claim 8, in which the internal tool (111) contains at least one electric heating element (113). 11. Installation according to claim 6 or 7, in which the pipe processing machine (11) contains external tools (114), which include interchangeable cutting tools (115) for cutting openings (38) in the lateral surface of the cardboard pipe (11) and interchangeable embossing tools (116) for making bigos (36) in the lateral surface of the cardboard tube (11). 12. Installation according to claim 11, in which the external tools (114) contain interchangeable embossing tools (117) for making grooves (39). 13. Installation according to claim 6 or 7, comprising edge cutters (118) for cutting down longitudinally extending slots (38) in the lateral surface of a cardboard pipe (11). 14. Installation according to claim 6, in which the folding machine (120) contains vacuum suction cups (121) for bending stiffness walls (32) outward from the side surface of the cardboard tube (11). 15. Installation according to claim 6, in which the folding machine (120) has rotary grippers driven by an electric motor (122, 123) for folding the stiffening walls (32) into the bearing sections (30) of the cardboard tube (11). 16. The apparatus of claim 15, wherein the rotary grippers (122, 123) are rotatable by step electric motors (124, 125) and pneumatically move up and down.

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