WO2008118078A1

WO2008118078A1 - Method and device for manufacture of a loading pallet made of metal

Info

Publication number: WO2008118078A1
Application number: PCT/SE2008/050312
Authority: WO
Inventors: Claes NORDSTRÖM
Original assignee: CROSSBORDER TECHNOLOGIES AB
Current assignee: CROSSBORDER TECHNOLOGIES AB
Priority date: 2007-03-27
Filing date: 2008-03-19
Publication date: 2008-10-02
Anticipated expiration: 2009-09-27
Also published as: SE0700777L

Abstract

The present invention relates to a method for manufacture of a loading pallet (1) made of metal, which pallet comprises a framework of bars serving as support legs, load bearing bars and stabilising and stiffening bars. The method involves the bars being formed from metal strip rolled to the shape of profiled sections which are thereafter cut to lengths which depend on the size of the pallet (1) being manufactured, a number, which depends on the pallet size, of each type of bar, whose length depends on the pallet size, being fixed in predetermined positions relative to one another in a fixture which likewise depends on the pallet being manufactured, and the bars being riveted together at predetermined points at which the bars abut against one another. The device used in the manufacture comprises partly a fixing station (5), provided with a fixture, which depends on the size of the pallet (1) being manufactured, to make it possible to place and fix in the fixture a number, which depends on the pallet size, of each type of bar, whose length depends on the pallet size, in predetermined positions relative to one another, and partly a riveting station (6) for riveting the bars together at predetermined points at which the bars abut against one another.

Description

Method and device at manufacture of a loading pallet of metal

Background to the invention The present invention relates to a method for manufacture of a loading pallet made of metal, which pallet comprises a framework of bars serving as support legs, load bearing bars and stabilising and stiffening bars. The present invention also relates to a device for use in the manufacture of a pallet made of metal.

The manufacture of pallets made of metal is known. Such pallets and a way of making them are described in, for example, SE-B-450 245. That method involves the constituent bars of the pallet being joined together by welding. A problem with welding is that not every kind of metal can be welded or that the strength and durability of the resulting finished pallet is not optimum. Another problem is that known arrangements for manufacture of pallets made of metal are difficult to reset to different pallet sizes.

Brief summary of the invention

An object of the present invention is therefore to propose for the manufacture of loading pallets made of metal, a method which is quick and easy to carry out in a short time on all kinds of metals, metal alloys and combinations of metals and results in a strong and durable pallet. The method is characterised in that the bars take the form of metal strip rolled to the shape of profiled sections which are thereafter cut to given lengths which depend on the size of the pallet being manufactured, that a given number, depending on pallet size, of each type of bar, whose length depends on the pallet size, are fixed in predetermined positions relative to one another and that the bars are riveted together at predetermined points at which the bars abut against one another. Riveting also makes it possible to dispense with expensive and difficult rust protection treatment of the pallets.

Another object is that the device for use in the manufacture of loading pallets made of metal should be of simple construction, easy to work with and easy to reset for the manufacture of pallets of different sizes. The device should also be able to work quickly. The device is characterised in that it comprises partly a fixing station so configured that after the rolling of metal strip to the shape of profiled sections intended to constitute said bars and after the cutting of said sections to given lengths depending on the size of the pallet being manufactured, it allows the placing therein of a given number, depending on pallet size, of each type of bar, whose length depends on the pallet size, in predetermined positions relative to one another, and partly a riveting station for riveting the bars together at predetermined points at which the bars abut against one another.

Other objects and advantages of the invention will be apparent to one skilled in the art from studying the attached drawings and the detailed description set out below of preferred embodiments.

Brief description of the drawings

Fig. 1 is a schematic plan view of a simple version of a device for use in the manufacture of loading pallets made of metal; Fig. 2 is a schematic plan view of a more advanced further development of the device according to Fig. 1 ;

Fig. 3 depicts in perspective view a loading pallet manufactured by applying the method and the device according to the invention;

Figs. 4 and 5 are side views of parts of the pallet according to Fig. 3; Fig. 6 is a perspective view of a version of part of a bar serving as a support leg for the loading pallet; and

Fig. 6a is a view in section through a detail of Fig. 6.

Detailed description of preferred embodiments of the invention Figs. 1 and 2 thus depict schematic plan views of various versions of a device used in the manufacture of loading pallets 1 made of metal, which pallets comprises a framework of various kinds of bars. Thus pallets 1 manufactured according to the present invention comprise bars serving as support legs 2, load bearing bars 3 and stabilising and stiffening bars 4 (see Figs. 3, 4 and 5). The bars 2, 3, 4 are made from metal strip which is rolled in a conventional manner to an elongate profile. The resulting profiled sections may be identical for the various types of bars or be of different shapes depending on their intended use. The sections are thereafter cut to lengths which depend on the size of the pallet 1 being manufactured. A certain standard size of loading pallets has been internationally agreed for suitable dimensioning of, for example, trucks and other equipment for the handling of pallets and to ensure that pallets of a certain size and certain dimensioning cope with certain loads, but alternatively it is also possible to apply the method and the device according to the present invention to manufacturing specially ordered pallets, i.e. pallets of any desired size. After being cut to length, the bars 2, 3, 4 are fixed in predetermined positions relative to one another for subsequent joining together of the bars. To this end, the device according to the invention comprises a fixing station 5 so configured as to allow the placing therein of a given number, which depends on the size of the pallet 1 being manufactured, of each type of bar 2, 3, 4, whose length depends on the pallet size. To this end, the bars 2, 3, 4 of various types and/or lengths are brought from stock supply stations 14 in the vicinity of the fixing station 5.

According to the invention, the fixing of the various bars 2, 3, 4, which vary in number and length and possibly also in shape, is preferably effected by using a fixture (not depicted), i.e. the fixing station is provided with such a fixture. The bars 2, 3, 4 are joined together at a riveting station 6 by being riveted together at predetermined points at which the bars abut against one another.

In a preferred pallet version depicted in Figs. 3, 4 and 5, the bars serving as support legs 2 and the load bearing bars 3 run parallel with one another and the stabilising and stiffening bars 4 run transversely both to the bars serving as support legs and to the load bearing bars. To achieve this layout, the bars are placed in a corresponding manner in the fixture at the fixing station 5, followed by the bars serving as support legs 2 and the load bearing bars 3 being riveted at the riveting station 6 to the stabilising and stiffening bars 4 at predetermined points at which said bars serving as support legs and said load bearing bars abut against said stabilising and stiffening bars. In the version depicted, each bar of the respective type is also provided in a conventional manner with at least one intermediate portion 2a, 3a, 4a, two web portions 2b, 3b, 4b running substantially perpendicular to the intermediate portion, and one or more, preferably two, outer portions 2c, 3c, 4c which run outwards from the web portions and are substantially parallel with and displaced relative to the intermediate portion. Accordingly, the fixture is so configured that the bars serving as support legs 2 and the load bearing bars 3 in the fixture abut, via the intermediate portion 2a and 3a respectively and/or the outer portion or portions 2c and 3c respectively, against the outer portions 4c of the respective stabilising and stiffening bars 4. Thereafter the bars serving as support legs 2 and the load bearing bars 3 can, at the riveting station 6, be riveted to the stabilising and stiffening bars 4 at predetermined points in said portions 2a, 2c, 3a, 3c, 4c thereof. To facilitate the manufacture of the bars serving as support legs 2 and make it possible for the finished loading pallet 1 to be stationary with good friction on any substrate via them, the bars serving as support legs comprise a middle portion 7 and two end portions 8 and 9 each connected to the respective end of the middle portion and having substantially the same profile shape (see Fig. 6). The end portions 8, 9 of the bars serving as support legs 2 are cut to predetermined lengths, while the middle portions 7 are cut to a length which depends on the size of the pallet 1 being manufactured, i.e. the end portions 8, 9 are always of the same length irrespective of the size of the pallet being manufactured, whereas the length of the middle portions 7 varies with pallet size. The mutual length of the end portions 8, 9 may nevertheless vary, as illustrated in Fig. 6. Said portions 7, 8, 9 are joined together, while at the same time parts of the end portions 8, 9 are bent upwards. In the preferred version depicted, the end portions 8, 9 are joined together with the middle portion 7 by being inserted in the latter, which is followed by at least one "gill" 10 being stamped out or punched up through parts of the middle portion and the respective end portion (Fig. 6a) which have been brought together. The device according to the invention also comprises a conveying device 1 1 for moving the fixture with bars 2, 3, 4 in direction A from the fixing station 5 to the riveting station 6. To this end, the conveying device 11 may be configured in any advantageous manner, e.g. it may comprise a conveyor belt with the fixture placed on top of the belt or comprise an industrial robot which carries the fixture, and is therefore not further described here. The conveying device 11 may be controlled manually or automatically.

The riveting station 6 to which the fixture with bars 2, 3, 4 comes after the movement from the fixing station 5 comprises one or more riveting machines 12 for joining the bars together. In the version depicted, the riveting machine or machines 12 is/are adapted to being moved in directions B and C and to riveting the bars 2, 3, 4 together at various points in the longitudinal or transverse direction of the pallet 1 being manufactured, depending on the size of said pallet, in the depicted version with a whole standard-size pallet in the transverse direction of the pallet. The riveting machine or machines 12 is/are preferably controlled automatically with a view to optimum joining together of the bars 2, 3, 4 by riveting. Control is thus effected in such a way that the riveting machine or machines 12 in the version depicted is/are moved in direction B transversely across the pallet 1 being manufactured, from one longitudinal side of the pallet to the other. The movement is effected to a number of predetermined points which depends on the width of the pallet 1 being manufactured and hence on the number of bars 2, 3, 4 in the pallet. At each point, one or more rivet heads are thereafter moved on the respective riveting machine in a vertical direction (direction C) to and from contact with the bars 2, 3, 4 for riveting together thereof. The number of repeats of the procedure of movement in the longitudinal or transverse direction of the riveting machine or machines 12 across the pallet 1 being manufactured, and of movement in the vertical direction of the rivet head or heads of the respective riveting machine, depends on the width and/or length of the pallet being manufactured. Between said movements, the conveying device 11 is also used to effect a movement of the fixture with bars 2, 3, 4 in the transverse or longitudinal direction of the pallet 1 being manufactured until the joining together by riveting has been effected at all the predetermined points at which the bars 2, 3, 4 abut against one another. Alternatively, the fixture with bars may be moved by the conveying device 11 in directions B and C and the riveting machine or machines may be stationary or both the machines and the fixture with bars may be movable in said directions.

Depending on the size of the pallet 1 being manufactured, the riveting machine or machines 12 and/or the fixture with bars 2, 3, 4 are with advantage also moved various distances in the longitudinal or transverse direction of the pallet, and/or the fixture with bars 2, 3, 4 is moved various distances in the transverse or longitudinal direction of the pallet. Pallets 1 of various sizes may also be riveted together, in cases where there are at least two riveting machines 12, their mutual spacing being set in the transverse or longitudinal direction of the pallet being manufactured (direction D) before the riveting machines and/or the fixture with bars begins to be moved in the longitudinal or transverse direction of the pallet for the joining together by riveting.

As indicated above, the device according to the invention also comprises a control unit 13 for controlling preferably at least the riveting machine or machines 12 (including the rivet heads) and/or the conveying device 11 (see Fig. 1) or alternatively, in its most expanded form (see Fig. 2), for controlling the riveting machine or machines 12, the conveying device 11 and any other feed and conveying arrangement 15, industrial robots 16 etc. in order, for example, to place bars 2, 3, 4 in the fixture and take away finished pallets 1. In the version depicted, the control unit 13 is so configured that when it has caused the conveying device 11 to move the fixture with bars 2, 3, 4 from the fixing station 5 to the riveting station 6, it alternately causes the riveting machine or machines 12 to move in the longitudinal and transverse direction of the pallet 1 being manufactured and the conveying device to move the fixture with bars in the transverse or longitudinal direction of the pallet being manufactured. The control unit 13 also makes it possible to cause the riveting machine or machines 12 to move various distances in the longitudinal or transverse direction of the pallet 1 being manufactured and/or the conveying device 11 to move the fixture with bars 2, 3, 4 various distances in the transverse or longitudinal direction of the pallet. The purpose of this is to make it possible to manufacture pallets 1 of various sizes. Where there are at least two riveting machines 12 (or three riveting machines as in Fig. 2), the control unit 13 is so configured that it regulates the mutual spacing of the riveting machines in the transverse or longitudinal direction of the pallet 1 being manufactured according to the size of the pallet. The control unit 13 may also be so configured as to apply to the conveying device 11 the same pattern of movement as it applies to the riveting machine or machines. This may be effected either simultaneously with or instead of the control of the riveting machine or machines.

It will be obvious to one skilled in the art that the method and the device according to the present invention can be modified and altered within the scopes of the claims set out below without departing from the idea and objects of the invention. Thus the pallets may not only be of various sizes and hence comprise various numbers of bars of various kinds arranged in various ways but also comprise bars with profile shapes other than those depicted, and the points at which the bars abut against one another and are accordingly riveted together may vary. The configuration of the fixing and riveting stations and of the fixture, the riveting machines, the conveying device and the control unit may likewise vary within the scope of the invention.

Claims

Claims:

1. A method for manufacture of a loading pallet (1 ) made of metal and comprising a framework of bars serving as support legs (2), load bearing bars (3) and stabilising and stiffening bars (4), characterised in that the bars (2, 3, 4) are formed from metal strip rolled to the shape of profiled sections which are thereafter cut to lengths which depend on the size of the pallet (1 ) being manufactured, that a number, which depends on the pallet size, of each type of bar (2, 3, 4), whose length depends on the pallet size, are fixed at predetermined positions relative to one another in a fixture which likewise depends on the size of the pallet being manufactured, and that the bars (2, 3, 4) are riveted together at predetermined points at which the bars abut against one another.

2. A method according to claim 1 , characterised in that the bars (2, 3, 4) for the pallet (1 ) are placed in the fixture in such a way that the bars serving as support legs (2) and the load bearing bars (3) run parallel with one another and the stabilising and stiffening bars (4) run transversely to the bars serving as support legs and the load bearing bars, and that the bars serving as support legs (2) and the load bearing bars (3) are riveted to the stabilising and stiffening bars (4) at predetermined points at which said bars serving as support legs and said load bearing bars abut against said stabilising and stiffening bars.

3. A method according to claim 2, in which each bar (2, 3, 4) of the respective type is provided with at least one intermediate portion (2a, 3a, 4a), two web portions (2b, 3b, 4b) running substantially perpendicular to the intermediate portion, and one or more, preferably two, outer portions (2c, 3c, 4c) which run outwards from the web portions and are substantially parallel with and displaced relative to the intermediate portion, characterised in that the bars serving as support legs (2) and the load bearing bars (3) are placed in the fixture with the intermediate portion (2a, 3a) and/or the outer portion or portions (2c, 3c) abutting against the outer portions (4c) of the respective stabilising and stiffening bars (4), and that the bars serving as support legs (2) and the load bearing bars (3) are riveted to the stabilising and stiffening bars (4) at predetermined points in said portions (2a, 2c, 3a, 3c, 4c) thereof

4 A method according to any one of claims 1 -3, characterised in that profiled sections intended to constitute the end portions (8, 9) of the bars serving as support legs (2) are cut to predetermined lengths, that profiled sections intended to constitute the middle portions (7) of the bars serving as support legs (2) are cut to lengths which depend on the size of the pallet (1 ) being manufactured, and that cut profiled sections intended to constitute the end portions (8, 9) and middle portions (7) of the bars serving as support legs (2) are joined together while at the same time parts of the end portions are bent upwards

5 A method according to claim 4, characterised in that the end portions (8, 9) of the bars serving as support legs (2) are cut to two different lengths and that an end portion of each length is joined to a respective middle portion (7) 6 A method according to claim 5, characterised in that the end portions (8, 9) and middle portions (7) of the bars serving as support legs (2) are joined together by at least one gill (10) being punched up through parts of the middle portion and the respective end portion which have been brought together

7 A method according to any one of claims 1-6, characterised in that the bars (2, 3, 4) for the pallet (1) being manufactured are riveted together by the fixture with the bars placed in it being moved (A) to a riveting station (6) with one or more riveting machines (12) and by the riveting machine or machines being thereafter activated

8 A method according to claim 7, characterised in that the bars (2, 3, 4) for the pallet (1 ) being manufactured are riveted together by the riveting machine or machines (12) and/or the fixture with bars being moved (B, C) and riveting the bars together at various points in the longitudinal or transverse direction of the pallet being manufactured, and by the fixture with bars being moved (A) in the transverse or longitudinal direction of the pallet being manufactured between movements of the riveting machine or machines and/or of the fixture in the longitudinal or transverse direction of the pallet being manufactured

9. A method according to claim 8, characterised in that pallets (1 ) of various sizes are assembled by riveting by the riveting machine or machines (12) and/or the fixture with bars being moved (B) various distances in the longitudinal or transverse direction of the pallets being manufactured and/or by the fixture with bars (2, 3, 4) being moved (A) various distances in the transverse or longitudinal direction of the pallets being manufactured between the movements of the riveting machine or machines and/or of the fixture with bars in the longitudinal or transverse direction of the pallet being manufactured.

10. A method according to claim 9, characterised in that pallets (1 ) of various sizes are assembled by riveting by the mutual spacing of at least two riveting machines (12) being set in the transverse or longitudinal direction of the pallet being manufactured (D) before the movement (B) of the riveting machines and/or the fixture with bars in the longitudinal or transverse direction of the pallets being manufactured commences.

11. A device for manufacture of a loading pallet (1 ) made of metal and comprising a framework of bars serving as support legs (2), load bearing bars (3) and stabilising and stiffening bars (4), characterised in that the device comprises partly a fixing station (5) so configured that after the rolling of metal strip to the shape of profiled sections intended to constitute said bars (2, 3, 4) and after the cutting of said sections to given lengths depending on size of the pallet (1) being manufactured, it allows the placing therein of a given number, depending on the pallet size, of each type of bar, whose length depends on the pallet size, in predetermined positions relative to one another, and partly a riveting station (6) for riveting the bars (2, 3, 4) together at predetermined points at which the bars abut against one another.

12. A device according to claim 11 , characterised in that the fixture is so configured that the bars serving as support legs (2) and the load bearing bars (3) in the fixture run parallel with one another and in such a way that the stabilising and stiffening bars (4) in the fixture run transversely to the bars serving as support legs and the load bearing bars, and that the riveting station (6) is so configured that the bars serving as support legs (2) and the load bearing bars (3) are riveted to the stabilising and stiffening bars (4) at predetermined points at which said bars serving as support legs and said load bearing bars abut against said stabilising and stiffening bars.

13. A device according to claim 12, in which each bar (2, 3, 4) of the respective type is provided with at least one intermediate portion (2a, 3a, 4a), two web portions (2b, 3b, 4b) running substantially perpendicular to the intermediate portion, and one or more, preferably two, outer portions (2c, 3c, 4c) which run outwards from the web portions and are substantially parallel with and displaced relative to the intermediate portion, characterised in that the fixture is so configured that the bars serving as support legs (2) and the load bearing bars (3) in the fixture abut, via the intermediate portion (2a, 3a) and/or the outer portion or portions (2c, 3c), against the outer portions (4c) of the respective stabilising and stiffening bars (4), and that the riveting station (6) is so configured that the bars serving as support legs (2) and the load bearing bars (3) are riveted to the stabilising and stiffening bars (4) at predetermined points in said portions (2a, 2c, 3a, 3c, 4c) thereof. 14. A device according to any one of claims 11-13, characterised in that the device also comprises a conveying device (11 ) for moving (A) the fixture with bars (2, 3, 4) from the fixing station (5) to the riveting station (6).

15. A device according to claim 14, characterised in that the conveying device (11 ) is also configured for moving (B, C) the fixture with bars (2, 3, 4) for riveting together of the bars at various points in the longitudinal or transverse direction of the pallet being manufactured.

16. A device according to any one of claims 11-15, characterised in that the riveting station (6) comprises one or more riveting machines (12).

17. A device according to claim 16, characterised in that the riveting machine or machines (12) is/are configured for being movable (B, C) and for riveting the bars (2, 3, 4) together at various points in the longitudinal or transverse direction of the pallet (1 ) being manufactured, and that the conveying device (11 ) is configured for moving (A) the fixture with bars (2, 3, 4) in the transverse or longitudinal direction of the pallet (1 ) being manufactured.

18. A device according to claim 17, characterised in that the device also comprises a control unit (13) for controlling the movements of the riveting machine or machines (12) and the conveying device (11 ).

19. A device according to claim 18, characterised in that the control unit (13) is so configured that, when it has caused the conveying device (11 ) to move (A) the fixture with bars (2, 3, 4) from the fixing station (5) to the riveting station (6), it alternately causes the riveting machine or machines (12) and/or, via the conveying device, the fixture with bars to move (B) in the longitudinal or transverse direction of the pallet (1) being manufactured, and the conveying device to move (A) the fixture with bars in the transverse or longitudinal direction of the pallet being manufactured. 20. A device according to either of claims 18 and 19, characterised in that the control unit (13) is so configured that, depending on the size of the pallet (1 ) being manufactured, it causes the riveting machine or machines (12) and/or, via the conveying device, the fixture with bars (2, 3, 4) to move (B) various distances in the longitudinal or transverse direction of the pallet being manufactured and/or, depending on pallet size, it causes the conveying device (11 ) to move (A) the fixture with the bars (2, 3, 4) various distances in the transverse and/or longitudinal direction of the pallet being manufactured.

21. A device according to claim 20, characterised in that the riveting station (6) comprises at least two riveting machines (12) and that the control unit (13) is so configured that it sets (D) the mutual spacing of the riveting machines in the transverse or longitudinal direction of the pallet (1 ) being manufactured according to the size of the pallet being manufactured.