METHOD AND APPARATUS FOR PRODUCING SPACERS OR BLOCKS PRIMARILY FOR USE IN LOAD PALLET STRUCTURES

Abstract: A method and apparatus for producing spacers or blocks preferably for use in pallet structures as supporting elements for the deck and/or as blocks between load deck and stringers, said blocks consisting of sleeves made from sheet metal. An elongate, substantially rectangular sheet metal blank (11) is fed into a nip (7) formed by at least two corrugated rolls (1, 2) with its main plane inclined to the plane passing through the axes of the rolls. The front end (17) of the blank (11) is fixed in a groove (12) in the surface of the roll (1). When the rolls (1, 2) are rotated, the blank (11) is shaped in the roll nip (7) and is rolled on to the roll (1). After the rolls (1, 2) have rotated at least one revolution, the ready-shaped block is withdrawn or pushed from the roll (1) in an axial direction.

Description: Method and apparatus for producing spacers or blocks primarily for use in load pallet structures The present invention relates to a method and apparatus for producing spacers or blocks primarily for use in load pallet structures, as supporting element for the load deck and/or as blocks between load deck and stringers, the blocks consisting of sleeves made from sheet metal. Spacers or blocks of this type, which are incorporated in pallet structures are already described in a published Swedish patent application. The invention according to the latter relates to a method of manufacturing pallets by machine and a pallet manufactured according to the method, said pallets being provided with a deck supported by spacers or blocks and/or stringers. The blocks and/or stringers are preferably combined with fastening means for joining the blocks to the deck, this process taking place in a compression and joining station, the pressing together of deck and blocks taking place in a roll nip under a pressure of sufficient magnitude for causing the blocks to penetrate into the load deck, at least with its upper portion, to a depth such that fixation against rotation of the blocks in relation to its fixed position against the load deck is obtained.. Since a pallet is a product which is mass produced today, it is essential that the manufacture of the blocks included in a pallet can be manufactured efficiently, cheaply and at high speed. The present invention has the object of providing a method of producing spacers or blocks of the type mentioned in the introduction. What is essentially distinguishing for the invention here is that an elongate, substantially rectangular sheet metal blank is fed into a nip formed by at least two corrugated rolls, with its main plane inclined to the plane passing through the axes of the rolls, that the front edge of the blank is fixed at the surface of one roll, that the rolls are subsequently caused to rotate at least one revolution simultaneously as the blank is given a corrugated configuration on its passage through the nip substantially corresponding to the configuration of the corrugations on the rolls, that after fixation of the front edge of the blank against the surface of one roll, and after shaping in the roll nip, the blank is brought into engagement against said surface and accompanies the direction of rotation of the roll until the blank has assumed its sleevelike shape on the roll and that the block is then withdrawn or pushed from the roll in an axial directio . The present invention also has the object of providing an apparatus for carrying out the above-mentioned method, essentially distinguishing for this apparatus being that it includes at least two opposing, corrugated rolls, the corrugations of which are arranged for meshing and are at a pre-determined distance from each other to make a roll nip for shaping a sheet metal blank, said distance between the corrugations of the surfaces being somewhat larger than the thickness of the sheet metal to be shaped. By reason of the invention the production of spacers or blocks preferably for use in pallet structures can take place efficiently and economically. The rate of production is as high as 20-30 sleeves per minute. This is feasible, inter alia since the corrugation and circular bending of the block takes place at the same operation. Furthermore, riveting the overlapping portions of the sheet is carried out during the actual shaping of the block. Since a riveting method is used, galvanized sheet can also be used, which is to be preferred because of the many advantages of this material in relation to untreated or painted sheet metal. O PΓ The invention will now be described in detail with reference to the appended drawings, on which Figure 1 schematically illustrates a perspective view of an apparatus for carrying out the method in accordance with the invention. Figure 2 is a side view of the apparatus illustrated in Figure 1, Figure 3 illustrates in a side view how the shaping of the sheet metal blank takes place with the apparatus illustrated in figures 1 and 2, and Figure 4 is a side view of an alternative embodiment of a sleeve, shaped and riveted together with the aid of an apparatus in accordance with the invention. Figure 1 schematically illustrates a suitable apparatus for carrying out the method in accordance with the present invention, this apparatus comprising two shaping rolls 1 and 2, each mounted in a bearing housing 3 and 4, respectively. Rotation of the rolls 1 and 2 may be provide with the aid of gears 5, 6 driven by a means not illustra¬ ted in the Figure. The surfaces of the rolls 1 and 2 are corrugated and together form a roll nip 7, the rolls being spaced from each other so that the corrugations or teeth 8, 9, constituting the surfaces of the rolls 1, 2 do not come into contact with each other. By each of the rolls 1, 2 having its own bearing housing 3, 4 the spacing between the rolls can easily be regulated by shims or spacers 10 between the housings, which consequently affects the spacing between the rolls 1 and 2. A preferred spacing between the teeth or corrugations 8, 9 of the rolls is one which is somewhat greater than twice the thickness of the sheet metal blank 11 which is to be shaped. In its surface between two adjacent teeth 8 one roll 1 is formed with an axial groove 12 of a width substantially corresponding to the thickness of the sheet metal. The groove 12 is intended for locating the front edge 17 of the sheet 11 before the sheet is fed into the roll nip 7. The groove 12 extends along the entire length of the roll 1 in its axial 0 P1_ direction, right out to its free end so that the sheet 11 shaped between the rolls can be withdrawn axially from the roll 1. The tooth or corrugation 8 adjacent the groove 12 is formed with two axial grooves 13, 14 intended to co-act with hard metal pins 15, 16 projecting from the opposing roll 2 for riveting together the overlapping portions of the sheet metal blank 11. As will be seen in principle from Figure 3, an elongate, substantially rectangular sheet metal blank 11 is advanced with its main plane inclined to the plane through the axes of the rolls into the nip formed by the two corrugated rolls 1 and 2. The long sides 19, 20 of the blank 11 which extend in the advancing direction as the blank is advanced towards the nip 7, and after shaping the block form its end edge portions are conventionally formed with a sawtooth¬ like contour before the blank 11 is advanced into the nip 7. After the front edge 17 of the blank 11 has been located in the groove 12, the rolls 1, 2 are caused to rotate at least one revolution, whereby the blank 11 during its passage through the nip 7 is given a corrugated configura¬ tion substantially corresponding to the form of the corrugations or teeth 8, 9 on the rolls 1, 2. After shaping in the nip 7 the blank 11 surrounds the roll 1. In con¬ junction with the front edge 17 of the blank 11 being rotated one revolution, this edge being overlapped by the rear edge 18 of the blank 11, the overlapping portions are riveted together with the aid of the hard metal pins 15 and 16, which deform the sheet metal and impress it into the grooves 13, 14 in the roll 1. An impression in the sheet metal also takes place at the front edge 17 directly after the start of rotation of the roll 1, and due to this so-called pre-impression of the sheet metal, better riveting of the rear edge 18 is achieved than would other¬ wise be the case. After the rolls 1 and 2 have rotated at least one revolution, and the riveting has been accomplished, the block is withdrawn or pushed from the roll 1 with the aid of suitable means not illustrated in the figures. Should a cross-sectional shape other than round be desired, e.g. oval, this can be achieved by a subsequent mechanical compression of the block between compression jaws 21, 22 which are arranged for urging against each other with the aid of hydraulic cylinders 23, 24.

Claims: Claims 1. Method of producing spacers or blocks preferably for use in pallet structures as supporting elements for the deck and/or as blocks between load deck and stringers, said blocks consisting of sleeves made from sheet metal, c h a r a c t e r i z e d i n that an elongate, sub¬ stantially rectangular sheet metal blank (11) is advanced into a nip (7) formed by at least two corrugated rolls (1, 2) with its main plane inclined to the plane passing through the axes of the rolls (1, 2) that the front edge (17) of the blank (11) is fixed at the surface of one roll (1) that the rolls (1, 2) are subsequently caused to rotate at least one revolution simultaneously as the blank (11) is given a corrugated configuration at its passage through the nip (7) formed by the rolls (1, 2) , this configuration substantially corresponding to the shape of the teeth or corrugations (8, 9) or the rolls (1, 2) that by the fixation of the front edge (17) of the blank (11) against the surface of the roll (1) the blank (11) is brought into engagement against said surface after shaping in the roll nip (7) , and accompanies the roll (1) in its rotational direction until the blank (11) has assumed its sleeve-like shape on the roll (1) , and that the block is subsequently withdrawn or pushed from the roll (1) in an axial direction. 2. Method as claimed in claim 1, c h a r a c t e r¬ i z e d i n that the front edge (17) of the blank (11) engaging against the surface of the roll (1) overlaps by a pre-determined distance the rear or trailing edge (18) of the blank (11) after the roll (1) has rotated one revolution, before the block is removed from the roll (1) . 3. Method as claimed in claim 2, c h a r a c t e r¬ i z e d i n that the portion of the blank (11) , IJU EA OMPI engaging against the roll (1) and constituting the overlap of the rear edge (18) in relation to the front edge (17) , is fastened to the front edge portion by riveting with the aid of hard metal pins (15, 16) projecting from the surface of the opposing roll (2) after the rolls (1, 2) have rotated at least one revolution and immediately before the block is removed from its roll (1) . 4. Method as claimed in claim 1, c h a r a c t e r¬ i z e d i that the long sides (19, 20) of the blank (11) which extend in the advancing direction of the blank (11) when it is fed into the roll nip (7) and which, after shaping of the block form its end edge portions, are formed conventionally with a sawtooth-like contour before the blank (11) is advanced into the roll nip (7) . 5. Method as claimed in claim 3, c h a r a c t e r¬ i z e d i n that in riveting the overlapping portion, portions of the blank (11) engaging against the roll (1) are pressed into axial grooves (13, 14) arranged in the surface of the roll (1) , impression taking place with the aid of the hard metal pins (15, 16) projecting from the second opposing roll (2), said grooves (13, 14) coinciding with the location of the pins (15, 16) when the rolls (1, 2) rotate. 6. Apparatus for carrying out the method in accordance with any of the preceding claims, c h a r a c t e r¬ i z e d i n that it includes at least two opposing corrugated rolls (1, 2), the corrugations or teeth (8, 9) of which are adapted for meshing with each other on rotation, without the surfaces of the rolls (1, 2) coming into contact but being at a pre-determined distance from each other for the formation of a roll nip (7) for shaping a sheet metal blank (11) , said distance between the corrugations or teeth of the surfaces being somewhat 0 P1 larger than the thickness of the sheet metal blank (11) which is being formed. 7. Apparatus as claimed in claim 6, c h a r a c t e r¬ i z e d i n that the roll (1) has its surface formed with an axial groove (12) for locating the front edge (17) of the blank (11) before the blank is fed into the roll nip (7) and during the whole of the shaping procedure, said groove (12) extending right out to the free end of the roll (1) . 8. Apparatus as claimed in claim 6 or 7, c h a r a c ¬ e r i z e d i n that the rolls (1, 2) are disposed spaced from each other at a distance greater than double the material thickness of the blank (11) which is to be shaped. 9. Apparatus as claimed in any of claims 6-8, ' c h a r a c t e r i z e d i n that the roll (1) having the axial groove (12) has at least one further axial groove (13, 14) at a pre-determined distance from the first groove (12) , the latter groove or grooves being intended to co-act with at least one hard metal pin (15, 16) projecting from the opposing roll (2) for riveting together the overlapping portions of the blank (11), said other axial groove (13, 14) being situated in the surface of the roll and extending axially a short distance behind the first axial groove (12) in the rotational direction of the roll (1) . 10. Apparatus as claimed in claim 9, c h a r a c t e r¬ i z e d by two axial grooves (13, 14), for co-action with two hard metal pins (15, 16) projecting from the opposing roll (2) , being adapted in the surface of the first roll (1) on a corrugation or tooth (8) adjacent the first axial groove (12) which fixes the front edge (17) of the blank UH), both axial grooves (13, 14) being situated at a spacing from each other falling within the spacing between the overlapping front edge (17) and rear edge (18) in the periphery of the block.

Inventors: WAHLSTROEM OLLE LENNART WALFRI, WAHLSTROEM, OLLE, LENNART, WALFRID
Applicants: HAMMARBERG LARS, HAMMARBERG, LARS
Application year: 1984
Main classification: B65D19
IPC codes: B21D15, B65D19