WO2016185362A1

WO2016185362A1 - Machine and method for assembling pallets

Info

Publication number: WO2016185362A1
Application number: PCT/IB2016/052829
Authority: WO
Inventors: Roberto TALOZZI
Original assignee: Talozzi Roberto
Priority date: 2015-05-15
Filing date: 2016-05-16
Publication date: 2016-11-24
Also published as: EP3294509A1; ITUB20150824A1; EP3294509B1

Abstract

A machine (10) for assembling pallets (1) has a support structure (11) equipped with at least one frame (12) for the preparation of the parts of a pallet (1) for assembly, and comprises a mobile upright (13) slidably connected with the support structure (11) and laterally mobile; the upright (13) is equipped with nailing guns (14) that are vertically movable, at least one gun of which is arranged at the front ar.d at least one other gun of which is arranged at the rear to simultaneously nail, or with a slight time delay, the front part and the rear part of the parts of the pallet (1) prepared on the frame (12); the frame (12) is substantially vertical or is slightly tilted back with respect to the vertical, morevore the frame (12) is made so as to help resting the parts (2-6) of the pallet (1) and also a subsequent comfortable withdrawal; a method for assembling pallets made by the machine is also provided.

Description

"MACHINE AND METHOD FOR ASSEMBLING PALLETS" .

TECHNICAL FIELD OF THE INVENTION

The present invention concerns a machine and a method for assembling pallets.

In particular, the present invention concerns a semi^¬ automatic machine for assembling pallets that allows high production of pallets per worker involved.

STATE OF THE ART

Currently, there is increasing use, for loading, lifting and moving various goods, of flat bases on which the goods are rested, such bases are able to be moved through forklift trucks and are called pallets. Pallets consist of planks placed on top of cross members or blocks that leave free spaces for the introduction of the forks of the forklift trucks.

Pallets can be made completely from wood, even if the blocks can be made from plastic, and the various parts of the pallet are nailed together with zinc-plated metallic elements, for example nails, pins, fasteners, etc .

Figures 1 and 2 illustrate perspective views of a pallet of the common type wholly indicated with 1.

In this case, the pallet is formed from four layers, starting from the top, there is a series of planks 2 on which the load to be transported is rested, the planks 2 are in turn fixed to three cross members 3 that extend perpendicular to the planks 2 themselves.

The planks 2 and the cross members 3 form the load base or cover 4 of the pallet 1.

Under the cover 4 there are the blocks 5, which in the illustrated example are three for each cross member 3 and therefore are nine in total.

Finally, under the blocks 5 there are three boards 6 that extend parallel to the planks 2 of the cover .

As stated above, the space between the boards 6 and the loading base, determined by the blocks 5, makes it possible to slot in the equipment for lifting and moving the pallet with its load; generally, the aforementioned equipment consists of forks mounted for example on a forklift truck or a similar vehicle.

According to a known technology, the manual assembly of the pallet provides to form, the cover 4 by nailing the planks 2 with the cross members 3, to position the ^'blocks 5 in a reference frame, to fix the cover 4 to the blocks 5 by nailing from the upper side, then inverting the pallet and nailing the boards 6 to the blocks 5 from the lower side.

The manual assembly takes a lot of time and is also very tiring since the worker must support the weight of the nailing gun during all of the nailing operations of the pallet .

For automatic assembly very complex machines are used that operate in a similar manner to manual assembly and that in any case require the presence of two workers for arranging the parts that make up the pallet, since these parts must be rested on both sides of an advancing and formation line of the pallet.

Such machines for automatic assembly are expensive, being complex they also require laborious maintenance, and nevertheless do not obtain high productivity, requiring the presence of two workers.

It should be noted that during processing the two workers also have break times, having to wait for the nailing of the parts that make up the pallet before being able to arrange the parts that make up the next pallet .

PURPOSES OF THE INVENTION

A purpose of the present invention is to improve the state of the art.

Another purpose of the present invention is to provide a machine and a method that allow quick assembly of pallets with high productivity per worker employed.

Such a purpose is obtained thanks to the fact that the machine according to the present invention is able to carry out nailing simultaneously on both sides of the pallet, i.e. it has at least one nailing means arranged at the front and at least one nailing means arranged at the back of the pallet that is being assembled.

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

According to another aspect of the invention a method for assembling pallets according to claim 10 is provided .

The machine according to the present invention, having the possibility of moving, vertically and horizontally, the at least one nailing means arranged at the front and the at least one nailing means arranged at the rear, manages to obtain a high nailing speed even with only two nailing means.

Another purpose of the present invention is to provide a machine and a method for assembling pallets that are flexible, so that they can be easily adapted to different types of pallet.

Moreover, the adaptation to different types of pallet takes place in a short time period thanks to simple adjustment mechanisms.

Yet another purpose of the present invention is to provide a machine that is cost-effective to manufacture and to maintain. The machine according to the present invention is built in a simple and strong manner to allow operations without interruptions.

Thanks to the aforementioned simple and strong construction, the machine according to the present invention does not substantially require ordinary maintenance, nor extraordinary maintenance, and moreover all of the parts do not require lubrication.

Further advantageous characteristics are described in the dependent claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The characteristics of the present invention will become clearer to those skilled in the art from the following description and from the attached boards of drawings, given as a non-limiting example, in which:

figures 1 and 2 are two perspective views, front and rear, of an example of a common pallet;

figure 3 is a front view of the machine for the assembly of pallets according to the present invention;

figure 4 is a perspective view of part of the machine for assembling pallets according to figure 3, during its operation;

figures 5 to 13 illustrate an assembly sequence of a pallet on a machine according to the present invention; figure 14 is a perspective view of a detail of the machine for assembling pallets according to figures 3 and 4 ; and

figure 15 is a section view of the detail according to the previous figure.

EMBODIMENTS OF THE INVENTION

Figures 1 and 2 illustrate a common pallet that is used frequently for transporting goods, the structure of which has already been described previously in relation to the state of the art.

In the following description reference will be made to such a type of pallet, but it should be considered that the assembly machine and method according to the present invention can be used to assemble pallets even with different structures.

Figures 3 and 4 illustrate a machine for assembling pallets according to the present invention, which is wholly indicated with reference numeral 10.

The machine 10 essentially comprises a support structure 11 in which frames 12 for the assembly of pallets 1 are housed, and a mobile upright 13 that is equipped with a plurality of nailing means 14.

More specifically, in the case illustrated in figures 3 and 4, the support structure 11 of the machine 10 houses two frames 12 for the assembly of pallets 1. Thanks to this, while the machine 10 proceeds with the nailing of the parts of a pallet 1 preassembled beforehand on a first frame 12, the worker can prepare the parts of another pallet on a second frame 12.

According to a non-illustrated version of the present invention, the machine 10 can have a number of frames 12 even greater than two, for example three or four frames 12.

This can be useful for increasing the productivity of the machine using two or more workers to prepare on the frames 12 the parts of respective pallets ready for nailing .

If, on the other hand, due to a particular configuration of the pallet, or because the nailing means 14 do not allow high speeds and the operation of the nailing means 14 to complete a pallet takes a relatively long time, then a single worker can prepare the parts of the pallet even on two or more frames 12.

It should be noted that the machine 10 according to the present invention is thus flexible and can be modular with more frames 12 slaved by a single upright 13 with the nailing means 1 .

The best productivity is thus obtained from each worker without long waiting times or idle times.

It should also be noted that the overall dimensions of the machine according to the present invention are small and are in length slightly greater than the dimensions in length of two pallets, in height slightly greater than the size in height of a pallet arranged vertically, and in width slightly greater than the size in height of a pallet arranged vertically slightly tilted backwards. In other words, the machine is a little more bulky than two pallets (in the case with two frames 12).

Going back to the example illustrated in figures 3 and 4, the nailing operation of a pallet, through the mobile upright 13 with the means 14, requires a comparable time to the preparation of the parts of the pallet 1 on a frame 12 by a single worker.

In this example, it is therefore sufficient for the machine 1 to comprise a first frame 12 with a pallet previously assembled, the pallet then being completed by the nailing means 14, and a second frame 12 in which the parts of the pallet 1 are prepared by a single worker while the nailing operations in the pallet that is located on the first frame 12 are carried out.

Thereafter, when the means 14 have completed the nailing into the pallet on the first frame 12 and the worker has finished the preparation of the parts of the second pallet, the worker moves onto the first frame 12, controls the unlocking of the frame and extracts the finished pallet 1.

Meanwhile, the upright 13 moves on the second frame 12 and starts the nailing operation on the second pallet. The worker, having extracted the finished pallet 1, can proceed to prepare the parts of a new pallet on the first frame 12.

Thus, alternatively on the first and on the second frame 12, the worker prepares the parts of a respective pallet while the machine 10, through the upright 13 with the nailing means 14, completes the pallet on the frame 12 in which the parts of the pallet have been previously prepared by the worker.

As illustrated in figures 3 and 4, the support structure 11 comprises a front portion 15 in the form of a framework inside which the frames 12 for the assembly of the pallets 1 are fixed.

The front portion 15 is slightly tilted backwards with respect to the vertical, for example with an inclination of about from six to ten degrees with respect to the vertical.

Since it is tilted backwards, the front portion rests at the rear on two support legs 16 for resting the entire machine 10 on the ground.

The front portion 15 and the support legs can be connected by a rectangular base 17, and in turn the base 17 comprises support feet (not illustrated) , at least one of which has an adjustment in order to level the machine 10.

The front portion 15 comprises one or more upper horizontal cross members 18, one or more lower horizontal cross members 19, and at least two uprights 20, 21 that connect the cross members 18, 19.

The upper horizontal cross members can be made with H- shaped profiles, the uprights 20, 21 can be of the tubular type, for example with a square or rectangular section, and the lower cross members 19 can again be Pi- shaped profiles.

Alternatively, all of the elements that form the front portion can be tubes.

In any case, the constructive- elements that form the support structure 11, including the legs 16 and the base 17, are sized so as to define a very rigid structure. At the base of the machine 10 a conveyor belt 46 (figures 3, 4 and 14, 15) can also be found, which serves to feed certain parts that form the pallet 1.

The frames 12 are fixed to the support structure 11 with the same inclination as the front portion 15, this inclination backwards with respect to the vertical allows a more secure support of the parts that the worker will insert into the frame 12 to make up the pallet .

Thanks to the vertical or substantially vertical position of the frames 12, the preparation of the parts of the pallet by the worker is made easier.

Indeed, the worker is positioned in front of the frame 12 and can easily insert the parts on the frame itself without having to lean over the frame itself.

Figures 5 to 13 illustrate a preparation sequence of the parts of a pallet on a frame 12.

Hereafter, specific reference will be made to the assembly of a pallet 1 of the type illustrated in figures 1 and 2, i.e. a four-layer pallet in which, starting from the top, there is:

a cover 4 formed from seven planks 2 fixed to three underlying cross members 3 that extend perpendicular with respect to the planks 2 (first and second layer) ;

nine blocks 5, i.e. three equally spaced blocks 5 for each of the three cross members 3 (third layer) ; three boards 6 that extend parallel to the planks 2 of the cover 4 (fourth layer) .

It should however be considered that the frame 12 can also be used for pallets of different shape and composition without for this reason departing from the scope of the present invention. According to what is illustrated in figure 5, the frame 12 comprises a framework 22, formed for example from tubular elements, a bottom wall 23 and a series of horizontal shelves 24.

The position of the shelves 24 can be adjusted in height. Regarding this, two racks 25 can be provided attached to the wall 23 and two toothed wheels 26 can be provided arranged at the ends of the shelf 24.

By rotating together - for example through a connection shaft (not illustrated) - the two toothed wheels 26 that are engaged on the two racks 25, it is possible to move in height the position of the shelves 24, whilst maintaining their horizontal position.

When the desired position in height has been reached, the shelves 24 are fixed to the wall 23, or to the framework 22, through locking means (not illustrated) . The shelves 24 act as a support for the three boards 6 according to what is illustrated in figure 6.

It should be considered that the number and the position of the shelves 24 is a consequence of the number of boards 6, therefore if the number of boards were more than three, the shelves 24 should also be in equal number to that of the boards, i.e. more than three.

The frame 12 comprises rests 27 for the blocks 5, and since in the example of the pallet of figures 1 and 2 there are three blocks 5 for each board 6, i.e. nine blocks 5, there are also three rests 27 for each shelf 23, i.e. in total there are nine rests 27.

The rests 27 are arranged in the same position as the blocks 5 and are fixed to a horizontal beam 28 that is movable in the vertical direction through a series of linear actuators 29.

In particular, each beam 28 is connected to two actuators 29 arranged near to the ends of the beam 28 itself, these actuators being able to lift or lower the beam 28, with the rests 27, by a few centimetres.

For each beam 28 there are also means for maintaining the horizontal position that can be made practically with a scissor mechanism 30, whereas the actuators 29 can be double-acting pneumatic cylinders.

Thanks to the scissor mechanism 30, the beam 28 can move in height remaining horizontal and parallel to itself without jamming. Of course, the means for maintaining the horizontal position of the beam 28 can also be made in other ways.

For example, the two actuators 29 can be of the controlled actuation type and made the same and uniform with each other. Practically each of the two actuators 29 can comprise a screw jack actuated by an electric motor that moves in synchrony with the electric motor of the other jack.

Other types of actuation, arranged at the ends of the beam 28 with the same and uniform movements to each other, can be made for example with toothed wheels and racks.

Initially (see figure 6) , the beam 28 with the rests 27 is in lowered position to allow the worker to rest the boards 6 more easily on the respective shelves 24, then upon command by the worker, the actuators 29 lift the beam 28; the condition relative to the beam 28 in raised position is illustrated in figure 7.

It has to be noted that once the pallet is complete, a command will be carried out which shall bring back the beam 28 in the lowered position in order to allow to remove the pallet from the frame 12.

Each of the rests 27 for the blocks 5, comprises two side walls 31, 32 that thus constitute a seat for each block 5.

A first side wall 31 is fixed, having the function of a reference for the position of the block 5, whereas the second side wall 32, equipped with a respective actuator 33, is movable so as to stop the block 5 in a predetermined position as a function of the pallet that is being prepared.

The wall 32 can be in two positions: a first position in which the seat is wider, to allow easier insertion of the block 5 by the worker and a closed position, wherein the wall 32 rests on the block 5 so that the position is determined with precision.

The wall 32 is actuated, upon command of the worker, by means of the respective actuator 33, which for example can be made with a double-acting pneumatic cylinder, but of course can also be any other type of actuator suitable for the purpose.

The worker can comfortably withdraw the blocks 5 by taking them from the conveyor belt 46 which is at the base of the machine 10 and on which the blocks 5 themeselves are fed and can be found.

Figure 8 illustrates a preparation step of the pallet in which the worker has already positioned the blocks 5 on the rests 27 in front of the boards 6, and the movable walls 32 are in the position in which the seat is wider; in figure 9 the walls 32 are closed and rested on the blocks 5, so as to precisely define their position.

The position of the block 5 is therefore defined by the position of the walls 31 and by the subsequent movement of the wall 32 that places the block 5 in contact with the wall 31. Based on the geometry of the pallet that is being assembled, the position can be adjusted just as the number of seats for the blocks 5 can also be varied. Each group formed by the rest 27 , the side walls 31, 32 and the actuator- 33, can be added, or removed from the beam 28, and the position of the group can also be adjusted in the longitudinal direction with respect to the beam 28 to adapt to different types and sizes of pallet .

Even in this case, once the pallet is complete, a command will be carried out which will cause the walls 32 to move in the position in which the seat is wider, thus freeing the blocks 5 in order to allow to remove the pallet from the frame 12.

Figure 10 illustrates a further preparation step of the parts of the pallet 1; in this step, the worker inserts the cross members 3 that are rested vertically on the three lowest rests 27, for this purpose the rests 27 in lowest position are provided to be longer so as to allow the positioning of the cross members 3 in front of the blocks 5.

In a subsequent step, illustrated in figure 11, the worker moves, in front of the cross members 3, some supports 34 that are used to support the planks 2 that will form the cover 4 of the pallet 1.

As can also be observed from figure 5, the supports 34 are arranged at the sides of the pallet that is forming, and on each side the group of supports 34 is attached to a rotary vertical shaft 35 that is connected to a respective actuator 36.

In this specific case, the actuator 36 is of the linear type and actuates the rotation of the shaft 35 through a lever and connecting rod mechanism.

Of course, in order to rotate the shaft 35 rotary actuators could also be used, for example a geared motor .

It should also be noted that the movement of the supports 34 in front of the cross members 3, which in the embodiment illustrated in the figures takes place with a rotation, could be obtained in a different way, for example with a translation of the supports 34, which would initially be at the sides and outside the bulk of the pallet being prepared, then would be translated in front of the cross members 3, in this last case the shaft 35 that carries the supports 34 would be able to translate transversally instead of rotary.

The number and the position of the supports 34 is determined by the number and by the position of the planks 2, and therefore the supports 34 can be added or removed from the shaft 35 and their position in height can also be adjusted.

In the illustrated example, since there are seven planks 2, there are also seven supports 34. In a subsequent step, illustrated in figure 12, the worker rests the planks 2 on each support 34. The support 34 comprises at a first end an adjustable attachment 37 for the shaft 35, an arm 38, and at the second end a small resting plane 39 for the plank 2.

Therefore, once the supports 34 have been placed in work position, the worker can quickly and easily place all seven planks 2, or the number of planks provided for the pallet in formation, on the resting planes 39 of the supports 34.

Even in this case, once the pallet is complete, a command will be carried out which will move the supports 34 out of the bulk of the pallet in order to allow to remove the pallet itself from the frame 12.

Figure 13 illustrates the last preparation step of the pallet 1. In this step the worker closes above the pallet two wings 40, which each have a vertical rod 41 that rests above the planks 2 exerting a moderate pressure thereupon through elastic return means- (not illustrated) that act on the wings 40.

In this way, the wings 40 ensure that the parts, in particular the planks 2, not yet nailed of the pallet remain in the desired position for the subsequent nailing operation.

It should be noted that, for safety reasons, the closing of the wings 40 can also provide an approval for the subsequent nailing operation. In other words, without the closing of the wings 40 it is not possible to carry out the nailing and the mobile upright 13 does not move. Once the preparation of the pallet on one of the frames 12 is complete, the worker can command the nailing of the pallet that takes place completely automatically, and at the same time the worker can move on to another of the frames 12 to prepare another pallet.

The nailing operation of the pallet takes place through the nailing means 14 that are carried by the mobile upright 13.

The mobile upright 13 is slidably supported and can move horizontally with respect to the support structure 11. In particular, there are motor means that allow a horizontal lateral displacement in the two directions of the mobile upright 13, as indicated by the arrow F in figures 3, 4 and 14.

According to a version of the present invention, illustrated in greater detail in figures 4 and 13, the aforementioned motor means comprise a geared motor (not illustrated) that sets two toothed wheels 42 in rotation, said toothed wheels being an upper toothed wheel and a lower toothed wheel connected together by a shaft 43, which are engaged with two racks 44 also one upper and one lower.

Possibly, each of the two toothed wheels 42 can be set in rotation by a respective geared motor or electric motor, which are in turn synchronised with each other through electronic means, like for example rotation sensors of the encoder type and means for controlling the electric motor.

Since the two wheels 42 move in synchrony with each other, i.e. with the same speed and rotation angle, it is always ensured that the vertical position of the upright 13 is maintained with a fluid movement and without jamming.

Of course, for the lateral displacement of the upright 13 it is also to use different types of motor means, without departing from the scope of the present invention. For example, instead of the toothed wheels and the racks it is possible to use manoeuvring screws with relative mother screws arranged on the mobile upright .

In the version of the present invention illustrated in figures 3, 4, 14 and 15 the mobile upright 13 comprises three nailing means 14 in the front part and two nailing means 14 in the rear part.

However, without departing from the scope of the present invention, the number of nailing means 14 can also be different, both due to the type of pallet to be assembled, and to obtain certain results in terms of nailing speed.

The upright 13 also comprises vertical movement means (not illustrated) , to move the nailing means 14 vertically according to the direction indicated by the arrows H in figures 3, 4 and 14. The aforementioned vertical movement means can move the nailing means 14 vertically all together or each nailing means 14 can be moved independently by a respective vertical movement means .

In the case in which the vertical movement means move the nailing means 14 all together, then means are also provided for adjusting the distance between one nailing means 14 and the other.

In this way, it is always possible to adjust and adapt to the distances of the various parts of the pallet.

Each nailing means 14 reaches the necessary nailing position on the pallet, thanks to the combination of the horizontal displacement of the upright 13 and the vertical displacement provided by the vertical movement means that are in the upright 13 itself.

Figure 15 illustrates a section of the upright 13 in which it is clear that it comprises front and rear nailing means 14 that move together and that allow the nailing to be carried out on both sides of the pallet. In section, the upright 13 surrounds the support structure 11 with the cross members 18, 19 and the frame 12, and therefore comprises a hinged rear portion 131, 132, which can be open or locked through hooking means 133 to gain better access to the rear part of the support structure 11 and of the upright 13, for example for reasons of maintenance, repairs, etc.

Each nailing means 14 can comprise a nailing gun for a certain type of nail.

For example, one of the nailing means 14 arranged at the front and one of the nailing means 14 arranged at the rear in the upright 13 can insert nails or pins that are suitable for penetrating through the blocks 5.

The other nailing means 14 can insert fasteners that are suitable for the connection of the parts of the pallet of lesser thickness, i.e. for the connection of the planks 2 with the cross members 3.

It should be noted that, in the example pallet 1 illustrated in the figures, at the rear the boards 6 are connected only to the blocks 5 and therefore a single nailing means 14 may be sufficient for the insertion of nails or pins.

The second nailing means 14 illustrated in the figures can be provided for the assembly of pallets of a different type with elements of lesser thickness to be connected together. Moreover, the second nailing means 14 can also act as an alternative to the first nailing means 14 in the case of failure, malfunction and in the case in which the fixing elements are finished and it is not wished to interrupt the work cycle to fill the loader with the fixing elements.

Again considering the example pallet 1 illustrated in the figures in which in the front part there are parts of high thickness, such as the blocks 5 to be fixed with the cross members 3 and the planks 2, which thus need to be fixed with nails of a certain length, and parts of lesser thickness, such as the cross members 3 and the planks 2 to be fixed together, so that these parts need to be fixed with fasteners, it is necessary to provide at least two nailing means 14 one of which is suitable for inserting nails and the other is suitable for inserting fasteners.

In the example illustrated in the figures, there is also a third nailing means 14 suitable for the insertion of fasteners, because this makes it possible to decrease the assembly time of the pallet, especially in the case in which the pallet comprises a cover with a large number of planks, for example seven planks or nine planks. The three front nailing means 14 can simultaneously fix three crossing points of the parts of the pallet: a crossing point with a block 5 to be fixed to a cross member 3 and to a plank 2, and two crossing points to be fixed to a cross member 3 and to a plank 2.

For this purpose, the distance between the three front nailing means 14 must be adjusted in a manner corresponding to the distance between the planks 2.

According to the present invention, at the same time in which the nailing takes place on the front side, the rear nailing means 14, or where provided the two rear nailing means 14, can carry out the nailing on the rear side .

For this purpose, it should also be noted that the bottom wall 23 of the frame 12 comprises a series of openings 45 (figure 5) at the rear parts to be connected, i.e. at the crossing point of each block 5 with a board 6, which in the illustrated example are nine in number like the blocks 5.

In this way there is no need to flip over the pallet that is being assembled, and therefore eliminating the time that would have been necessary to flip it.

According to a version of the present invention, in order to promote the stabilization of the parts of the pallet the nailing on the front parts takes place slightly in advance with respect to the nailing of the rear part, for example such a time difference can add up to about two tenths of a second.

In the case of the pallet illustrated in figures 1 and 2, and with the mobile upright 13 comprising three front nailing means 14 and a rear nailing means 14, the nailing sequence takes place in the following way.

The upright 13 is arranged at the first nailing position, i.e. near to the middle of the first cross member 3, such a position is indicated in figure 13 with the broken line I.

The three front nailing means 14 that as stated above have been adjusted to a distance apart corresponding to the distance apart of the planks 2, proceed with the simultaneous nailing of three planks 2 at three points: starting from the top, the first point is located where there is the first block 5, the first cross member 3 and the first plank 2, the second and the third point are located in the respective crossing points of the first cross member 3 with the second and the third plank 2.

At the same moment, or with a slight time delay, the rear nailing means 14 proceeds with the nailing at the crossing point of the first board 6 with the first block 5.

The group of three front nailing means 14 and the rear nailing means 14 moves to the next three front crossing points and to the second rear crossing point.

Again starting from the top the points are: the fourth front point is located where there is the second block 5, the first cross member 3 and the fourth plank 2, the second and the third point are located in the respective crossing points of the first cross member 3 with the fifth and the sixth plank 2; at the rear the nailing means 14 proceeds with the nailing in the crossing point of the second board 6 with the second block 5, also in this case the rear nailing means 14 proceeds with the nailing simultaneously or with a slight time delay.

Therefore, the group of three front nailing means 14 and the rear nailing means 14 move to the last front crossing point, i.e. the seventh point starting from the top, and to the last or third rear crossing point.

In this step, at the front the nailing of the seventh plank 2 with the first cross member 3 and with the third block 5 takes place, and at the rear the nailing in the crossing point of the third board 6 with the third block 5 takes place, and also in this last case the rear nailing can take place simultaneously or with a slight time delay.

Once the nailing sequence on the first line I has ended, the upright 13 thus moves to the second nailing position, i.e. near to the middle of the second cross member 3, such a position being indicated in figure 13 with the broken line II.

The nailing sequence on the second line II takes place in a totally analogous manner to the nailing sequence that took place on the first line I.

It should be considered that possibly to avoid a pointless movement of the group of three front nailing means 14 and the rear nailing means 14 the nailing can start from the bottom since the aforementioned groups is already at the bottom.

Finally, once the nailing sequence on the first line II has ended, the upright 13 thus goes to the third nailing position, i.e. near to the middle of the third cross member 3, such a position being indicated in figure 13 with the broken line III.

In this case, since the end of the previous nailing sequence took place with the group of three front nailing means 14 and the rear nailing means 14 at the top, the nailing sequence will start again from the top exactly like in the nailing sequence on the first line I .

Therefore, it should be noted that the nailing operation for a pallet with the characteristics illustrated in figures 1 and 2 takes place with three movements of the upright 13 at the three nailing lines I, II, III and with three movements of the group of three front nailing means 14 and the rear nailing means 14, for each of the three nailing lines I, II, III.

As already stated above, the time necessary for the nailing according to the nailing sequence just illustrated corresponds to the time that the worker takes to prepare a pallet on a second frame 12.

In the case of different shaped pallets, the number of front and rear nailing means can be varied in a corresponding manner, as can the nailing sequence.

Once the pallet 1 is complete, the unlocking of the pallet from the frame 12 is actuated, the beam 28 will then return in the lowered position, the walls 32 move in the position in which the seat is wider and the supports 34 move out of the bulk of the pallet, thus also causing the opening of the wings 40, that way the worker is able to comfortably remove the pallet 1 from the frame 12.

The frame 12 allows then to easily place the elements forming the pallet 1 and subsequently also to free the pallet 1 from the frame 12 for an easy withdrawal of the pallet itself.

Therefore a considerable improvement is obtained compared to the known solutions which required a lateral or lower outlet of the frame forming and supporting the pallet and a subsequent opening of the frame itself.

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

The present invention has been described according to preferred embodiments, but equivalent variants can be conceived without departing from the scope of protection offered by the following claims.

Claims

1. Machine (10) for assembling pallets (1) comprising a support structure (11) equipped with at least one frame (12) for preparing for the assembly of the parts of a pallet (1), and a mobile upright (13) slidably connected with the support structure (11) and laterally movable through motor means, which is equipped with nailing means (14) for the nailing of the parts (2-6) of the pallet (1) prepared on the at least one frame (12), said parts comprising planks (2), blocks (5) which form the intermediate part of the pallet, cross members (3) and boards (6), wherein said at least one frame (12) is substantially vertical or is slightly tilted backwards with respect to the vertical, and wherein said mobile upright (13) comprises at least one nailing means (14) arranged at the front and at least one nailing means (14) arranged at the rear to simultaneously, or with a slight time delay, nail the front part and the rear part of said at least one pallet (1) characterized in that said at least one frame (12) comprises rests (27) on which to rest the blocks (5), and in that said rests (27) are fixed to a height-movable beam (28) of the frame (12), so as to facilitate the insertion of the parts forming the pallet and also the subsequent withdrawal of the pallet (1) once the pallet itself is complete.

2. Machine for assembling pallets according to claim 1, comprising at least two frames (12) for the preparation for assembly of the parts of a pallet (1) ·

3. Machine for assembling pallets according to claim 1 or 2, wherein said at least one frame (12) comprises adjustable shelves (24) for supporting boards (6) that constitute the lower part of the pallet (1).

4. Machine for assembling pallets according any one of the previous claims, wherein said rests (27) are adjustable in the longitudinal direction with respect to said beam (28) .

5. Machine for assembling pallets according to any one of the previous claims, wherein each of said rests (27) comprises two side walls (31, 32) that thus constitute a seat for each block (5) .

6. Machine for assembling pallets according to any one of the previous claims, wherein each of said rests (27) arranged in lower position are provided to be longer so as to allow the positioning of cross- members (3) in vertical position in front of the blocks (5), said cross members (3) constituting an upper part of the pallet (1).

7. Machine for assembling pallets according to any one of the previous claims, wherein said at least one frame (12) comprises supports (34) on which to rest planks (2) that constitute the upper part of the pallet (1) .

8. Machine for assembling pallets according to any one of the previous claims, wherein said at least one nailing means (14) arranged at the front and at least one nailing means (14) arranged at the rear are vertically movable with respect to said mobile upright (13).

9. Machine for assembling pallets according to any one of the previous claims, comprising a conveyor belt (46) which is at the base of the machine (10) and on which the blocks (5) are fed and can be found.

10. Method for assembling a pallet (1) formed by parts (2-6), said parts being planks (2), blocks (5), which form the intermediate part of the pallet, cross members 3 and boards (6), comprising the steps of:

preparing the parts (2-6) of the pallet (1) for assembly on a frame (12) provided with portions to receive said parts,

carrying out the nailing of the parts of the pallet (1) prepared on the at least one frame (12) through nailing means (14) arranged on a mobile upright (13) ,

wherein said preparation of the parts of the pallet (1) for assembly takes place on a frame (12) that is substantially vertical or is slightly tilted back with respect to the vertical, so as to promote the insertion of the parts of the pallet (1) on said frame (12), and wherein

said nailing of the parts of the pallet (1) takes place at the front and at the rear simultaneously, or with a slight time delay, between the front part and the rear part of said at least one pallet (1) characterized in that said frame (12) comprises rests (27) on which to rest blocks (5), which are height-movable, so as to facilitate the insertion of the parts forming the pallet and also for the subsequent withdrawal of the pallet (1) once the pallet itself is complete.

Method for assembling pallets according to claim 11, wherein the preparation of the parts of the pallet (1) for assembly takes place on a first frame (12), whereas the nailing of the parts of the pallet (1) takes place, through nailing means (14) arranged on a mobile upright (13), in a time substantially similar to the time of the preparation of the parts of said pallet (1) for assembly.