The present invention is in regard to a machine and a method for the assembly of pallets.

In particular, the present invention concerns a machine for assembling pallets which allows a high output of pallets for each operator employed, extensive operational flexibility in terms of the type and dimensions of the pallets to be assembled and the automation of certain steps of the assembly.

The machine and the method according to the present invention are also designed to allow the unloading of a pallet complete with nailing in an automatic way, e.g. through the use of programmable manipulators or robots.

DESCRIPTION OF THE PRIOR ART

In the Italian patent n. 102015000015283, in the name of the same Applicant, a semiautomatic machine and a method are described for the assembly of pallets, the aforementioned machine and the aforementioned method having several advantages such as operational flexibility and productivity.

In the Italian patent n. 102018000008549, in the name of the same Applicant, improvements to the machine of the previous patent are described, in particular with regard to the support frame of the parts that make up the pallet.

The machines described in these patents ensure excellent performance in terms of high productivity and quality of the end product, but the need is felt to increase automation in the assembly of pallets, improving the unloading phase of the pallet completed by the machine for pallet assembly.

OBJECTS OF THE INVENTION

One object of the present invention is to improve the state of the art.

Another object of the present invention is to provide a machine and method that allow for quick assembling of pallets by increasing automation in pallet assembly.

This purpose is achieved thanks to the fact that in the machine according to the present invention the preparation and nailing of the pallet take place in different areas with respect to the area where the unloading of the finished pallet takes place, thanks to this, in addition to the automatic assembly of the pallet, it is also possible to automate pallet unloading, e.g. through the use of programmable manipulators or robots.

According to an aspect of the present invention, a machine for the assembly of pallets according to claim 1 is presented.

According to another aspect of the invention, a method for the assembly of pallets according to claim 13 is provided.

Further advantageous characteristics are described in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the present invention will be best understood by anyone skilled in the art from the following description and accompanying drawings, provided by way of non-limiting example, wherein: figure 1 illustrates a perspective view of the machine for the assembly of pallets according to the present invention; figure 2 is a schematic sectional view of a variant of the machine for the assembly of pallets as referred to in figure 1; figures 2a and 2b illustrate a schematic sectional view of other versions of the machine for the assembly of pallets as referred to in figures 1 and 2; figure 3 is a schematic plan view of the machine for the assembly of pallets as referred to in the previous figures: figure 4 is a front view of a group of the machine for the assembly of pallets according to the present invention; figure 5 is a schematic sectional view of a portion of the pallet being nailed and of part of the machine according to the present invention; and figure 6 is a schematic perspective view of a detail of the machine and of the pallet during a nailing step.

EMBODIMENTS OF THE INVENTION

The figures illustrate a machine for the assembly of pallets, generally indicated by the reference 1, which essentially includes a support structure 2, formed for example by a lattice of welded tubes, so as to obtain a stable and sturdy structure.

As can be seen in figures 1 and 3, the support structure 2 includes at least one nailing area 3, arranged in the centre of the machine 1, at least one pallet preparation area 4 for the orderly positioning of the parts that will form the pallet by an operator 25 and at least one unloading area 5 of the pallet; the pallet preparation and unloading areas are located on the sides of the nailing area 3, so as to be separated from each other, to allow the pallet unloading area 5 to be isolated with protectors in the event that there is a programmable manipulator or robot 26 for unloading completed pallets.

Indicatively, the pallet preparation area 4 has the same front width dimensions as the pallet unloading area 5, that is, these areas 4, 5 have a front width dimension slightly greater than the maximum dimension of a pallet mounted on a support frame, the nailing area 3 also has a front width dimension similar to that of the other areas 4, 5 or, depending on the type of relative movement necessary for nailing the pallet, it can have larger dimensions.

Overall, the machine for the assembly of pallets 1, according to the present invention, has a front dimension slightly greater than the maximum dimension of three pallets mounted on a support frame.

In this description, if a component or means is defined as “front”, it is meant that it acts starting from the front of the machine 1, i.e. from the side on which the operator 25 and the programmable manipulator or robot 26 are positioned and act during the assembly and unloading of a pallet, while in the case in which a component or means is defined as “rear”, it means that it acts starting from the back of the machine, i.e. from the side opposite to that on which the operator 25 and the programmable manipulator or robot 26 are positioned and act during the assembly and unloading of a pallet.

In the figures, the pallet preparation area 4 is located to the right of the nailing area 3, while the pallet unloading area 5 is located to the left of the nailing area 3, although, naturally, the two positions can be exchanged; what does matter is that the two areas 4, 5 are well separated from each other.

The support structure 2 includes a front portion 2b which has a lying plane and a specific dimension and which extends according to the front width of the machine 1, the lying plane of this front portion 2b is slightly inclined backwards with respect to the vertical, e.g. with an inclination of about six to about ten degrees with respect to the vertical.

This inclination of the front portion 2b helps the preparation of the pallet parts by the operator 25. In fact, the operator 25 who is facing the pallet preparation area 4 can comfortably insert the pallet parts without having to bend forward.

The machine 1 includes, in the front portion 2b, at least two mobile frames 6a, 6b for assembling pallets of any type; the aforementioned mobile frames 6a, 6b are horizontally slidable in the support structure 2 throughout the front width of the machine 1.

According to a version not shown of the present invention, the machine 1 can include a number of frames 6a, 6b even greater than two, e.g. three or four frames.

In figure 1, the frame 6a located in the pallet preparation area 4 is illustrated complete with the parts of a pallet 60 to be nailed, while the frame 6b located in the nailing area 3 is illustrated schematically as an outline only to better highlight the parts of the machine 1 which are located behind the frame 6b; however, frame 6b should also be understood as including all the parts of a pallet to be nailed. For the sliding of the frames 6a, 6b, the support structure 2 includes an upper guide element 7, equipped with upper driving means 8, and a lower guide element 9, equipped with lower driving means 10.

Each guide element 7, 9 has two sliding elements which, in the version of figure 1, include a rail arranged on the front side and another rail arranged on the rear side of the respective guide element 7, 9.

Figure 2 illustrates, in a schematic section, a variant of the version of the machine 1 of figure 1; there are two upper longitudinal guides and two lower longitudinal guides, arranged parallel to each other at a short distance; associated with each upper and lower guide is a frame 6a, 6b which can slide along these guides.

More in detail, the support structure 2 includes two upper guide elements 7a, 7b and two lower guide elements 9a, 9b. The aforementioned guide elements are positioned one above the other, are independent and fixed to the support structure 2; furthermore, the sliding guides 7a, 7b, 9a, 9b include respective rails. In this version, the mobile frame 6a, which is in an advanced position with respect to the mobile frame 6b, slides on the outermost guides 7a and 9a, while the mobile frame 6b slides on the innermost guides 7b and 9b. Next to each sliding guide 7a, 7b, 9a, 9b there are their respective driving means 8a, 8b, 10a, 10b.

In the version of figure 1, the frame 6a comprises at the top wheels or sliding pads 11, 12 inserted in the front rail of the upper guide element 7 and at the bottom, wheels or sliding pads 13, 14 inserted in the front rail of the lower guide element 9.

Similarly, the frame 6b comprises at the top wheels or sliding pads 15, 16 inserted in the rear rail of the upper guide element 7 and at the bottom wheels or sliding pads 17, 18 inserted in the rear rail of the lower guide element 9.

Also in the version of figure 2, the frame 6a comprises at the top wheels or sliding pads 11, 12 inserted in the rail of the upper guide element 7a and at the bottom wheels or sliding pads 13, 14 inserted in the front rail of the lower guide element 9a.

As illustrated in figure 2, the second frame 6b includes at the top wheels or sliding pads 15, 16 inserted in the rail of the respective upper guide element 7b, this guide 7b being located just below the guide 7a. At the bottom, the second frame 6b includes wheels or sliding pads 17, 18 inserted in the rail of the respective lower guide element 9b, this guide 9b being located just below the guide 9a.

In both versions, the frames 6a, 6b can move independently of each other throughout the front width of the support structure 2, going from the pallet preparation area 4 to the pallet unloading area 5, passing through the nailing area 3.

The independent motion ability of the mobile frames 6a, 6b is ensured by the fact that they are located on parallel staggered planes and that each mobile frame 6a, 6b has its own independent motorization; the staggered parallel planes of the mobile frames 6a, 6b are substantially parallel to the lying plane of the front portion 2b.

As can be seen in figure 1 the upper 8 and lower 10 driving means include an upper rack 19 and a lower rack 20; for the movement of the mobile frames 6a, 6b, an upper toothed wheel 21 with a vertical axis which engages in the upper rack 19 and a lower toothed wheel 22 with a vertical axis which engages in the lower rack 20 are also provided. The toothed wheels 21, 22 are connected to each other by a rotary shaft 23 to motor means 24, the aforementioned motor means 24 can be, for example, an asynchronous electric motor for each frame 6a, 6b.

Also in the version of figure 2, the upper 8a, 8b and lower 10a, 10b driving means to drive the frames 6a, 6b, can include two upper racks and two lower racks (not shown in figure 2) with their respective upper vertical axis toothed wheels that engage with the upper racks and their respective lower vertical axis toothed wheels that engage with the lower racks (not shown in figure 2).

Also in this version, the toothed wheels are driven by motor means 24 arranged on the frames 6a, 6b (not shown in figure 2), similar to those of the version in figure 1.

The motor means 24 allow a controlled movement of the frames 6a, 6b.

In particular, in the nailing area 3, the frames 6a, 6b move horizontally by a step corresponding to the position of the parts of the pallet to be nailed; furthermore, through the motor means 24, the frames 6a, 6b are positioned in the pallet preparation area 4 where an operator 25 can prepare the parts that will form the pallet, and in the pallet unloading area 5 where the finished pallet is unloaded.

It should be borne in mind that the driving means now described for the controlled displacements of the frames 6a, 6b in the horizontal direction are only an example of embodiment and that in any case, within the scope of the present invention, any type of driving means is included capable of carrying out the aforementioned controlled displacements of the frames 6a, 6b.

In figure 3, a plan view shows the machine 1 for the assembly of pallets wherein the operator 25 can be seen in the pallet preparation area 4 and the programmable manipulator or robot 26 in the pallet unloading area 5.

The pallet unloading area 5, where the programmable manipulator or robot 26 is located, is equipped with protections 27 which completely isolate the programmable manipulator or robot 26 from the operator 25.

In the nailing area 3, the machine 1 includes at least one nailing group 27a for a plurality of front nailing means 29 and one or more possible rear nailing means 30; the nailing group 27a includes at least one vertical nailing upright 28. As illustrated in figures 1 and 2, in the nailing group 27a, the vertical upright 28 is inserted into an auxiliary frame 28a in a sliding manner in a first horizontal direction, indicated by the arrows X (figures 1 and 2), for this movement in the first horizontal direction X first guides 28b and first displacement means (not shown) are provided. More specifically, the vertical upright 28 can be displaced in the horizontal direction X, parallel to the front portion 2b of the support structure 2, to obtain special types of nailing to be specified hereinafter, this movement is obtained via first displacement means which can be, for example, of the toothed wheel and rack type, or of another type capable of creating a linear motion.

In turn, the auxiliary frame 28a is inserted in a sliding manner, via second guides 28c, with respect to the central part 2c of the support structure 2 along a second horizontal direction, indicated by the arrows Y (figures 1 and 2), perpendicular to the first direction X; the auxiliary frame 28a is driven along the second horizontal direction Y, by means of second displacement means (not shown), with respect to the central part 2c of the support structure 2.

The second displacement means of the auxiliary frame 28a are used to adapt the position of the nailing means 29, 30 with respect to the staggered planes of the frames 6a, 6b - in these frames 6a, 6b the pre-assembled pallet 60 is located to be subjected to nailing - and include devices (not shown) capable of producing a linear movement, for example fluid-dynamic, compressed air or oil jacks, or electric jacks, or means similar to the first displacement means, of the toothed wheel and rack type, or even another type.

The displacement of the auxiliary frame 28a along the second horizontal direction Y is approximately in the order of magnitude of 20-40 cm and corresponds to the distance of the staggered planes of the mobile frames 6a, 6b; it should be noted that, in this case, the auxiliary frame 28a therefore has two operating positions to allow for the nailing of the pallet via the nailing means 29, 30.

The aforementioned two operating positions are: a front position, closer to the lying plane of the front portion 2b, and a rear position further away from the lying plane of the front portion 2b, so as to adapt to the staggered planes of the mobile frames 6a, 6b. According to a version of the present invention not shown, the number of mobile frames could be even greater than two, for example three arranged on three staggered planes and, in this different case, the auxiliary frame 28a would have three nailing operating positions.

When the auxiliary frame 28a has finished moving along the second horizontal direction Y and is in an operational nailing position, it rests or is blocked on specific abutment portions (not shown) located in the central part 2c, such abutment portions increasing the stability of the auxiliary frame 28a during the pallet nailing operations. The auxiliary frame 28a can be fixed to the abutment portions by means of locking means, for example latches, or kept resting on the abutment portions through the continuous action of the second displacement means.

Ultimately, the front nailing means 29 and the rear nailing means 30 which are located on the vertical upright 28 are movable according to the two horizontal directions X, Y with respect to the support structure 2 to adapt to the different types of nailing and the positions of the staggered planes of the mobile frames 6a, 6b.

Another version of the present invention is illustrated in Figure 2a; in this version the main difference is that the movement along the second horizontal direction Y, necessary to adapt the position of the nailing means 29, 30 with respect to the staggered planes of the frames 6a, 6b, is obtained through a displacement of the same frames 6a, 6b.

In this version of the present invention, the auxiliary frame 28a and the second displacement means are missing, so the vertical upright 28 can carry out displacements with respect to the support structure 2 only in the first direction X.

For this reason, the first guides 28b of the upright 28 slide directly on the support structure 2.

To obtain a displacement along the second horizontal direction Y, there are third displacement means which include a mobile subframe 70, substantially shaped like a frame, equipped with third guide means 71.

Furthermore, the mobile subframe 70 includes the upper guide elements 7a, 7b and the lower guide elements 9a, 9b, with these guide elements carrying in turn the at least two frames 6a, 6b.

The third guide means 71 are positioned above and below the mobile subframe 70 and are directly fixed to the support structure 2 with the possibility of sliding with respect to the latter, in this way they enable the displacement of the mobile subframe 70 along the second horizontal direction Y and consequently also the displacement of said at least two mobile frames 6a, 6b along the second horizontal direction Y.

As for the previous version, the displacement along the aforementioned second horizontal direction Y is approximately in the order of magnitude of 20-40 cm and corresponds to the distance of the staggered planes on which the mobile frames 6a, 6b are located.

A further version of the present invention is illustrated in Figure 2b; in this version the main difference is that the displacement along the second horizontal direction Y, necessary to adapt the position of the nailing means 29, 30 with respect to the staggered planes of the frames 6a, 6b, is obtained through fourth displacement means allowing a displacement of at least one of the at least two frames 6a, 6b in the second horizontal direction Y.

The fourth displacement means comprise mobile supports 80 for one of the mobile frames 6a, 6b; in particular, in the embodiment illustrated in figure 2b, the frame 6b is equipped with mobile supports 80, for example made with telescopic elements. The mobile supports 80 allow the mobile frame 6b to be displaced, i.e. moved forward towards the front portion, along the second horizontal direction Y by a distance of approximately 20-40 cm which, as mentioned, corresponds to the distance of the staggered planes of the mobile frames 6a, 6b.

Thanks to the mobile supports 80, the frame 6b can move on the same plane as the frame 6a and therefore the vertical upright 28 can directly nail the pallet located on this frame without having to move along the second direction Y.

Alternatively, the mobile supports could be applied to the mobile frame 6a, or the mobile supports could be applied to both mobile frames 6a, 6b. Also in this version of the present invention the auxiliary frame 28a and the second displacement means are missing. Therefore, the vertical upright 28 can move with respect to the support structure only along the first direction X, with the first guides 28b of the upright 28 directly sliding on the support structure 2.

An advantage provided by the versions illustrated in figures 2a and 2b is that, thanks to the displacement of the frames 6a, 6b in the second direction Y, the frame 6a or 6b on which the operator is loading the pallet parts can be positioned closer to the operator, thus improving working conditions.

The front nailing means 29 are designed to insert nails or staples starting from a first side or front of a pre-assembled and non-nailed pallet, while the rear nailing means 30 are designed to insert nails or staples starting from a second side or rear of a preassembled, non-nailed pallet.

Furthermore, the rear nailing means 30 act as an opposite band to the front nailing means 29 with respect to a pre-assembled and not yet nailed pallet. Furthermore, the rear nailing means 30 act and insert nails, pins or staples in the same direction, but opposite with respect to the front nailing means 29.

The front nailing means 29 and any rear nailing means 30 are movable in a third substantially vertical direction, indicated by the arrows Z (figures 1 and 2); for this purpose each nailing means 29, 30 includes a vertical driving means (not shown) which vertically displaces, with respect to the main structure of the vertical upright 28, the aforementioned nailing means 29, 30 according to the direction indicated by the arrows Z.

In the example of figure 1 there are seven front nailing means 29 and three rear nailing means 30; considering having to create a four-layer type of pallet with seven strips and three crosspieces for the load base, or pallet cover, and three boards for the lower support of the pallet, the seven front nailing means 29 match the seven strips of the pallet cover and the three rear nailing means 30 match the three lower support boards. The four-layer pallet referred to in the examples includes, starting from the top of the pallet: a cover made up of seven strips fixed to three underlying crosspieces that extend perpendicularly to the strips (first and second layer); nine blocks, i.e. three equidistant blocks for each of the three crosspieces (third layer); three boards that extend parallel to the cover strips (fourth layer).

However, it should be considered that the frame 6a, 6b can also be used for pallets of different shape and composition without departing as a result from the scope of the present invention.

In the example illustrated in the figures, the vertical driving means of the nailing means 29, 30 have the function of regulating the vertical position of the nailing means so as to be in the right position on the pallet to carry out nailing based on the dimensions, shape and type of nailing required for the pallet itself.

Based on the type of nailing on the pallet, for example, when double nailing staggered in an oblique direction is required, the vertical driving means can displace the nailing means 29, 30 along the third vertical direction Z by a given vertical height, while for the horizontal displacement, the vertical nailing upright 28 can move along the first horizontal direction X by a given horizontal value; the combination of the two vertical and horizontal displacements allows the required movement to be obtained for double nailing in an oblique direction.

The aforementioned vertical driving means can move along the third vertical direction Z the nailing means 29, 30 all together, or each nailing means 29, 30 can be moved independently by a respective vertical driving means.

This situation can occur, in particular, when the nailing means are fewer than the number of vertical positions in which nailing is to be carried out on the pallet; in this case, each nailing means 29, 30 must move vertically individually or in groups according to the vertical direction Z, to cover all the positions of the pallet on which nailing is to be carried out in the vertical direction.

As regards the positions in the horizontal direction, to cover all the positions of the pallet in the horizontal direction X on which nailing should be carried out, these displacements are carried out in an indirect manner via the displacement of the mobile frame 6a or of the mobile frame 6b.

Once the operator 25 has finished preparing the pallet parts on one of the mobile frames 6a, 6b in the pallet preparation area 4, the mobile frame 6a, 6b can move to the nailing area 3.

The horizontal displacement of the mobile frame 6a, 6b occurs by carrying the pallet to be nailed and aligning a first vertical row of parts of the pallet to be nailed with the nailing means 29, 30; the latter, therefore, carry out nailing of the parts of the pallet along the aforementioned vertical line; during this phase the mobile frame 6a, 6b stops and waits for the nailing of the parts to be completed; then, the mobile frame 6a, 6b moves, positioning the pallet and aligning a subsequent vertical row of parts to be nailed with the nailing means 29, 30.

The horizontal displacements of the mobile frame 6a, 6b continue in successive steps until all the vertical rows of the parts of the pallet 60 are subjected to nailing, i.e. nailing of all the parts of the pallet 60 is complete.

There may be cases in which the pallet 60 to be assembled is particularly wide and consequently so is the related mobile frame 6a, 6b on which the parts of the pallet are located. The pallet preparation area 4 may be insufficient to completely contain the mobile frame 6a, 6b, which obviously has the dimensions necessary to contain the preassembled pallet to be nailed.

Therefore the mobile frame 6a, 6b goes beyond the preparation area 4 of the pallet into the nailing area 3; furthermore, the same problem could occur for the pallet unloading area 5, also in this case the mobile frame 6a, 6b could go beyond the aforementioned area 5 into the nailing area 3.

It would therefore be necessary to widen the pallet preparation area 4 and the pallet unloading area 5, but this would lead to the consequence of having to increase the overall front width dimensions of the machine 1.

To avoid this problem, the vertical nailing upright 28, which is normally found substantially in the centre of the nailing area 3, can move to a position outside the centre of the area 3, towards the right or towards the left as the case may be, to allow it to accommodate the part of the frame 6a, 6b that goes beyond the pallet preparation area 4 or the pallet unloading area 5.

Thanks to this measure, the machine 1 can also accommodate frames 6a, 6b of larger dimensions than the respective pallet preparation area 4 and the pallet unloading area 5, without increasing the dimensions of the machine 1 itself.

In figure 4, by way of a non-limiting example, a mobile frame 6a, 6b for the assembly of pallets according to the present invention is shown; this frame substantially corresponds to that of the Italian patent no. 102018000008549 in the name of the same Applicant.

Naturally, the aforementioned mobile frame 6a, 6b is only an example embodiment and in any case, within the scope of the present invention, any type of frame capable of accommodating the parts of a pallet for subsequent nailing can be included.

The frame 12 includes a moulding frame 31, formed for example by horizontal elements or horizontal tubular elements 32 and vertical elements or vertical tubular elements 33 connected to each other, for example, in a substantially rectangular shape, and transverse groups 34 which are arranged substantially horizontally and are adjustable in the vertical direction because during the preparation of the pallet they act as support for the boards and support for the blocks that form the pallet.

The number and position of the transverse groups 34 is a consequence of the number of boards on the pallet, so if the number of boards were greater than three, the transverse groups 34 should also be in the same number as the number of boards, i.e. greater than three; similar considerations can also be made for the other parts of the pallet, such as the blocks, the crosspieces and the strips.

On each vertical tubular element 33 there is a vertical guide 35 and a rack 36; the transverse groups 34 have at the ends slides sliding on the vertical guides 35 and two first toothed wheels 37, each of which engages with a rack 36; the two toothed wheels 37 are connected to each other via a first shaft 38; the two toothed wheels 37 are rotated by a gearmotor 39.

Maintaining a substantially horizontal orientation, the position of the transverse groups 34 is therefore adjustable in height through the simultaneous rotation of the two toothed wheels 37 which are engaged on the two racks 36.

Furthermore, since the gearmotor (29) can be provided with an automatic brake, for example of the electromagnetic type, once the vertical position of the transverse group 34 necessary for the formation of the pallet has been reached, this position is maintained by the automatic locking of the gearmotor brake 39.

Each transverse group 34 also includes a shelf 40, equipped with substantially vertical rear supports 41. In the example illustrated in figure 4 there are two supports 41 for each shelf 40, the supports 41 allow the pallet boards to be positioned on the shelves 40 with sufficient safety to prevent the risk of the boards falling to the rear.

In front of the shelf 40, the transverse group 34 includes supports 42 for the blocks of the pallet to be assembled, in the example of the mobile frame 6a, 6b there are three blocks for each board of the pallet to be assembled, i.e. nine blocks, consequently the supports 42 are three for each transverse group 34, i.e. in total there are nine supports 42.

It should be noted that the three supports 42 of the lower transverse group 34 are protruding to a greater extent (in the direction of the second horizontal direction Y) so as to allow the positioning of the cover crosspieces in front of the blocks.

The supports 42 are arranged in the same position as the blocks of the pallet to be assembled and are fixed to a horizontal beam movable in a vertical direction via a series of actuators 44 and in particular, each beam 43 is connected to two actuators 44 arranged near the ends of the beam 43 itself, these actuators 44 can raise or lower the beam 43, with the supports 42, for example by a few centimetres. To obtain a synchronized movement of the two ends of the beam 43, two synchronization mechanisms 45 are provided, arranged at the two ends of the beam 43.

Each synchronization mechanism 45 includes a section of rack 46, arranged vertically and fixed to a support frame 37 of the transverse group 34, the actuator 44 also being fixed to this frame 47, and a second toothed wheel 48 which in turn is placed on and fixed to a second connecting shaft 49 for the two synchronization mechanisms 45 arranged at the ends of the beam 43; the shaft 49 is inserted on two supports 50, for example two rolling bearings, fixed to the beam 43, the aforementioned supports 50 allowing the rotation of the shaft 49.

Each rack 46 is therefore locally fixed because it is connected to the support frame 47 of the transverse group 34, while the toothed wheels 48 with the shaft 49 and the supports 50 are connected to the beam 43 which is raised and lowered based on the command to the actuators 44.

Front-back adjustment means are also provided (not shown) to adjust the shelf 40 with the supports 41 in a front-back direction.

This adjustment is used to adapt the frame 6a, 6b, with the related supports and rests, to pallets of different thicknesses or different transverse dimensions; by “front-back direction” it is meant a direction transverse or orthogonal to a vertical direction, in use, as well as transverse or orthogonal to a direction from one side to the other of the frame 6a, 6b or to the horizontal direction X of displacement of the vertical upright 28. The frame 6a, 6b also includes supports 51 which are used to support the strips which will form the pallet cover.

The supports 51 are arranged on the sides of the pallet being formed, and on each side the group of supports 51 is fixed to a fourth rotatable vertical shaft 52 which is connected to a respective actuator 53.

In this specific case, the actuator 53 is of the linear type and activates the rotation of the shaft 52 via a lever and connecting rod mechanism.

Obviously, rotary actuators, e.g. a gearmotor, could also be used to turn the shaft 52.

It should also be noted that the displacement of the supports 51 in front of the crosspieces of the pallet to be assembled, which in the example occurs with a rotation, could be obtained in a different way, for example with a shifting of the supports 51, which would initially be located on the sides and outside the footprint of the pallet being prepared, then they would be shifted to in front of the crosspieces of the pallet to be assembled, in this latter case the shaft 52 which carries the supports 51 would be transversally shiftable rather than rotatable. The number and position of the supports 51 are determined by the number and position of the strips of the pallet to be assembled, and therefore the supports 51 can be added or removed from the shaft 52 and their height position can also be adjusted.

The operator 25 places the strips on each support 51; the support 51 includes at a first end an adjustable attachment 51a for the shaft 52, an arm 51b, and at the second end a small flat surface 51c for supporting the pallet strip to be assembled.

Therefore, once the supports 51 have been prepared in the working position, the operator 25 can quickly and easily arrange all seven strips, or the number of strips required for the pallet to be assembled, on the flat surfaces 51c of the supports 51.

When the nailing of the parts of the pallet is completed, a command will be applied to cause the supports 51 to move out of the footprint of the pallet to allow the pallet to be unloaded from the frame 6a, 6b.

At the end of the pallet preparation, the operator 25 closes two doors 54 above the parts of the pallet, each of which doors has a vertical bar 55 which rests on the strips of the pallet to be assembled, exerting moderate pressure through elastic return means (not shown) which act on the doors 54.

In this way, the doors 51 ensure that the parts of the pallet, in particular the strips of the pallet to be assembled, not yet nailed, remain in the desired position for the subsequent nailing operation.

Since the loading base or pallet cover can also be assembled at an earlier stage, e.g. be already made up of three crosspieces and seven strips nailed together, the operator 25 can simply place the cover with the three crosspieces, or the number of crosspieces required for the pallet to be assembled, on the lower supports 42; in this case, the supports 51 are not necessary and can be removed.

Figure 5 shows a schematic sectional view of a portion of the pallet being nailed and of part of the machine 1.

The following can be observed: a four-layer pallet 60 in the nailing phase, some front nailing means 29, one of which inserts nails or pins 61 while the other inserts staples 62, a rear nailing means 30 which inserts nails or pins 61, and an abutment means 30a. According to what is also illustrated in detail in figure 6, the abutment means 30a enables the machine 1 to carry out nailings that are closed or riveted at the rear.

For this purpose, the vertical upright 28 includes at the rear at least one abutment means 30a which moves vertically by means of respective movement means on the main structure of the vertical upright 28 in a coordinated manner with the respective front nailing means or more than one means 29.

The matching means 30a has the function of closing or riveting the nails or pins inserted by the front nailing means 29 into the parts of a pallet supported by a frame 6a, 6b.

As already mentioned above, on the rear part of the vertical upright 28 there are also rear nailing means 30 which, in the example illustrated in figure 5, insert nails or pins 61 of a specific type suitable for penetrating the blocks of the pallet 60.

Naturally, the abutment means 30a are staggered or staggerable with respect to the rear nailing means 30.

The operations to obtain the assembly of a pallet by means of the machine 1 according to the present invention are described below.

Initially, the operator 25, who is in the pallet preparation area 4, neatly arranges the parts of the pallet 60 in one of the mobile frames 6a, 6b, optionally the loading base or pallet cover can be assembled previously, so the operator 25 can load this already assembled part directly into the mobile frame 6a, 6b.

Naturally, by loading the loading base or pallet cover already assembled previously, the preparation times of the pallet parts on the mobile frame 6a, 6b are shortened.

When the operator 25 has finished preparing the parts of the pallet 60 they will provide a preparation end signal and the frame 6a, 6b is then displaced from the pallet preparation area 4 to the nailing area 3. It should be noted that the nailing area 3 is separated from the pallet preparation area 4, therefore another frame 6b or 6a can be positioned in the pallet preparation area 4, allowing the operator to prepare the parts of another pallet 25.

In the nailing area 3, the vertical upright 28 is normally located in the centre of this area 3; however, the vertical upright 28 can also be positioned on one side of the area 3 to facilitate the disengagement of the pallet preparation area 4 or of the pallet unloading area 5.

Once the vertical upright 28 is in the working position, the mobile frame 6a, 6b can be displaced, bringing the pallet into alignment with the first nailing position, i.e. close to the centre line of the first crosspiece, with the front nailing means 29 and the rear nailing means 30. If the number of nailing means 29, 30 is sufficient to carry out all the front and rear nailings necessary for the pallet, then the mobile frame 6a, 6b can be moved, via the respective driving means, bringing the pallet into alignment with the next or second nailing position.

Possibly, if double nailings staggered in an oblique direction are provided, the vertical upright 28 can move along the first horizontal direction X of the horizontal dimension required and the vertical driving means can move the nailing means 29, 30 of the vertical dimension required along the third vertical direction Z.

Even if the front nailing means 29 and the rear nailing means 30 are smaller in number than the vertical positions on which to carry out the nailing, the vertical driving means can move the nailing means 29, 30 by the required vertical height.

Nailing continues in successive steps until all the vertical rows of the parts of the pallet are subjected to nailing, i.e., ultimately, until the nailing of all the parts of the pallet 60 is complete.

Then the frame 6a, 6b is displaced, via the respective movement means, from the nailing area 3 to the pallet unloading area 5.

In this pallet unloading area 5, the programmable manipulator or robot 26 can automatically pick up the completed pallet 60 from the frame 6a, 6b; thanks to the presence of the protections 27, the programmable manipulator or robot 26 is isolated from the operator 25 who can work in the pallet preparation area 4 without risk.

Optionally, the removal of the completed pallet 60 from the frame 6a, 6b can also take place manually.

Therefore, once freed from the pallet 60, the empty frame 6a, 6b can return to the pallet preparation area 4.

In the meantime, in the pallet preparation area 4, the operator 25 has prepared on the frame 6b, 6a the parts for a new pallet 60 to be nailed.

When the first empty frame 6a, 6b coming from the pallet unloading area 5 and passing through the nailing group 27a located in the nailing area 3 has returned to the pallet preparation area 4, then the second frame 6b, 6a loaded with the parts for a new pallet 60 to be nailed can move to the nailing area 3; before this displacement of the second frame 6b, 6a towards the nailing area 3, the auxiliary frame 28a must shift, along the second horizontal direction Y, by the dimension prescribed for the position of the nailing means 29, 30 to the different plane of the second frame 6b, 6a and to allow the actual passage of the second frame 6b, 6a through the nailing group 27a, i.e. through the vertical nailing upright 28.

The required displacement dimension along the second horizontal direction Y for the auxiliary frame 28a substantially corresponds to the distance of the staggered planes of the frames 6a, 6b.

It should be noted that the auxiliary frame 28a can move along the second horizontal direction Y only when both mobile frames 6a, 6b are in the pallet preparation area 4, and in this regard the machine 1 includes a safety device which ensures that the position of the mobile frames 6a, 6b is for both in the pallet preparation area and which, consequently to the positioning of both mobile frames 6a, 6b in the pallet preparation area 4, provides enabling for the shifting of the auxiliary frame 28a.

Similarly, for the versions shown in figures 2a and 2b, the second frame 6b or 6a loaded with the parts for a new pallet 60 to be subjected to nailing can move to the nailing area 3 only when the displacement occurs along the second horizontal direction Y of the mobile subframe 70 or when the displacement occurs in the second horizontal direction Y of the mobile supports 80.

It has thus been seen how the invention achieves the intended purposes.

Thanks to the separation of the pallet preparation area 4 from the pallet unloading area 5 a remarkable improvement is obtained compared to known solutions which did not allow the use of a programmable manipulator or robot for unloading the finished pallet, because said programmable manipulator or robot would have been in the same area where the operator worked, causing obvious safety issues.

Despite the separation of the pallet preparation area 4 from the unloading area 5, the overall dimensions of the machine 1 remain compact.

Furthermore, a machine in accordance with the present invention has driving components such as to guarantee high versatility and adaptability for the creation of even very diversified pallets; thanks to the automation of pallet unloading, the productivity of the machine is further improved.

The present invention has been described according to preferred embodiments, but various equivalent versions are possible still within the scope of the appended claims.