WO1980002268A1

WO1980002268A1 - Load-bearing,torsionally rigid metal platform

Info

Publication number: WO1980002268A1
Application number: PCT/NO1980/000015
Authority: WO
Inventors: M Birkeland
Original assignee: M Birkeland
Priority date: 1979-04-20
Filing date: 1980-04-21
Publication date: 1980-10-30
Also published as: NO791329L; NO145049B; EP0027119A1; NO145049C

Abstract

A load-hearing, torsionally rigid metal platform, preferably a loading platform for vehicles, consisting of laterally adjacent metal sections, preferably extruded Al-sections provided with co-operating longitudinal coupling devices. The sections (1) have a U-shaped cross-section comprising two parallel flanges (2, 3) and an intermediate web (4) and are coupled with the aid of the said coupling devices (5, 6) which are of insertion and swing type and snap type respectively, with the opening of one section facing web (4) of the other section so as to produce parallel, closed channels (7) since the upper and lower flanges (2, 3) of the section constitute upper and lower faces of the platform and extend in the longitudinal direction of the platform. The said snap coupling devices comprising beads (10) and recesses (11) are coupled with the aid of e.g. bolts, pins (12) arranged in line with holes (13, 14) in beads (10) and recesses (11), respectively, the said pins being inserted from the open side of the Al-section when assembling the sections to a metal platform. By a special design of the insertion and swing coupling devices it is brought about that excessive sliding friction between the various components of the coupling devices does not occur during the actual insertion and swinging operation effected when two U-shaped sections have to be coupled. The loading platform produced is relatively lighter than a loading platform produced of closed sections.

Description

LOAD - BEARING, TORSIONALLY RIGID METAL PLATFORM

The present invention relates to a loading platform for vehicles consisting of metal sections, preferably extruded aluminium sections, arranged next to one another and provided with co-operating longitudinal coupling devices.

Loading platforms of the initially stated type have been previously developed and marketed by the applicant, whereby it has proved possible to reduce the weight of the loading platform construction in such a way as to enable the payloads to be increased and the operating revenue from the goods vehicle to be augmented. The said reduction in weight of loading platform constructions is brought about owing to the fact that with a self-supporting, torsionally rigid loading platform it is not necessary to make use of longitudinal support beams. As a result the loading platform frame normally provided in conjunction with tiltable loading platforms may be omitted since the self-supporting, torsionally rigid loading platform can be mounted direct on the chassis of the vehicle, possibly with the aid of hinges and detachable coupling devices so as to enable backwards tilting and possibly lateral tilting. The hydraulic tilt rams with lift arms, if any, are generally arranged on the vehicle chassis with the centre part of the loading platform designed in such a way that lifting and tangential forces act centrally on the loading platform. It is the intention of the present invention to produce a load-bearing torsionally rigid metal platform or loading platform which can be easily constructed from identical metal sections, preferably extruded Al-sections, whereby the sections can be coupled with the aid of coupling devices provided on the latter and can be locked especially safely to one another with the aid of bolts, pins etc. located in aligned holes in two adjacent sections and gradually tightened as the sections are coupled.

A further object of the invention consists in providing a section for the construction of loading platforms which can be produced more simply than the previously applied closed sections, inasmuch as use is made of an open section. When extruding open Al-sections use can be made of Al-alloys having higher tensile strength and a better surface quality than can be used when extruding closed sections. This is due to the fact that when extruding open sections the extruding die is not provided with an internal pin.

According to the invention the above is achieved with the aid of the features stated in the characteristics of the subsequent main claim and subordinate claims, i.e. use is made of sections arranged in the longitudinal direction of the loading platform and having a U-shaped cross-section, the said sections being coupled to one another in such a way that the opening of one section faces the base or web of an adjacent section and held together by means of co-operating coupling devices provided on the sections. Owing to the design of the sections and the provision of the coupling devices stated in the claims a lighter, more reliable and cheaper product subject to smaller tolerances is achieved than if corresponding closed sections are produced by extruding Al-alloys.

The invention is described in greater detail below with reference to the drawing, where figure 1 shows a cross-section of a loading platform consisting of a number of laterally arranged U-shaped sections with coupling devices, and figure 2 shows an alternative design of the coupling devices on that side of the sections which constitutes the load deck of the loading platform.

Figure 1 shows a cross-section of a loading platform consisting of a number of U-shaped sections 1 arranged next to one another as mentioned above, with U-shaped edge sections 22, which serve to regulate the width of the loading platform to a maximum permissible width (2.5 m) before securing the lateral edge sections with the aid of bolts or pins, possibly by welding the upper flanges 23 and possibly the lower flanges 24 at 26.

Section 1 has a U-shaped cross-section comprising upper and lower parallel flanges 2, 3 and an intermediate web 4. The sections are coupled to one another with the aid of upper and lower coupling devices 5, 6, with the opening of one section facing web 4 of the adjacent section and so on throughout the entire width of the loading platform. The coupling devices 5 of the upper section flanges 2 comprise a projection 8 at the free edge of the flange which co-operates, at the base of flange 2, with a recess 9 (groove) of an adjacent section 1. Projection 8 is at a lower level than the surface of flange 2 so as to give rise to a step 15 and an inclined face 16. The outer side edge 19 of the projection and the rear side edge 20 form parts of a circular cylindrical surface with the axis situated in the corner between step 15 and the inclined face 16. The recess 9 at the base of flange 2 is shaped as a semi-circular groove open to the top and with a semi-circular cross-section, the opening of which is halfways covered by a projection 18 from the base of flange 2. The said projection has an inclined edge 18 the inclination of which faces in the opposite direction to that of the inclined face 16 of projection 8. The radius of the semi-circular groove 9 is complementary to the radius in the cylindrical face of which the front and rear edges 19» 20 of projection 8 form parts.

When joining two adjacent sections 1 projection 8 is inserted into groove 9 so that the front edge 19 of the projection abuts the bottom of the groove since the flanges 2 of the sections are at an angle to one another. Then the one section 1 with projection 8 is swung downwards, with the fulcrum defined by the corner 21 which roughly adjoins the lower limit of the inclined edge 18 of projection 17. One section is turned in relation to the other section until the flanges 2 are aligned with one another, in which position the step or face 15 of projection 8 is located, at the base of flange 2, against the lower face of projection 17 and the outer limiting edge of the semi-circular groove 9 abuts the underside of the other flange 2 while the front and rear edges 19, 20 of projection 8 come to rest against the semi-circular walls of the circular groove 9. As a result the sections are locked in respect of one another both in the transverse and vertical directions. The inclined faces 16, 18, which are so designed as to enable the above insertion of projection 8 into the recess 9, now constitute a Y-shaped groove in the upper surface of the sections. During the last phase of the said swinging down of one section the coupling devices 6 at the lower flanges 3 of the sections are caused to engage since they are designed as snap devices comprising an upward facing bead 10 at the free end of flange 3 and a complementary recess 11 at the base of flange 3.

The said snapping process is enabled by the fact that the flanges 2, 3 are to some extent mutually resilient owing to the material and the dimensions of the material used. Recess 11 and bead 10 of the lower flange 3 are so adapted in relation to the coupling devices at the upper flange 2 that the upper flanges 2 are aligned with one another and constitute a level plane whereas the lower flanges 3 are also aligned with one another and constitute a level plane. The sections 1 are accordingly fixed in relation to one another, and the lower snap connector of coupling device 6 can be subsequently reinforced by fitting bolts, which are introduced from the open side of one section and down into the aligned holes 13, 14 provided in recess 11 and bead 10. Use may be made of threaded bolts and nuts which are tightened from the underside, or preferably of huck type pins which are prestressed with the aid of a special tool and secured by means of a locking sleeve clamped firmly about the stem of the pin which is provided with annular beads. Using these pins it is possible to achieve, according to the pin prestress and the mutual spacings, a friction and compression joint between the sections of snap coupling 6, which corresponds to every material.

With a loading platform composed of the said sections 1 in the above manner a self-supporting torsionally rigid loading platform is achieved, which is, in addition, relatively lighter than a corresponding loading platform produced of closed sections since the adjacent walls of two such sections are replaced by a single wall, i.e. web 4 of the loading platform according to the invention, it being possible to make the said web 4 relatively thinner than the total thickness of the two adjacent walls in the closed sections while maintaining an equally large resistance against buckling stresses.

In the design of coupling devices 5, 6 it has proved possible to arrive at a shape which facilitates the production of the extrusion tool, and this applies especially to the coupling devices 5, where there are only two cylindrical faces 19, 20 on projection 8 which must match the semi-cylindrical faces in groove 9. It is accordingly simpler to produce a tool enabling the extrusion of a section with the two said faces 19 and 20 instead of a semi-cylindrical face co-operating with the semi-cylindrical face in groove 9.

Fig. 2 of the drawing shows an alternative design of the coupling devices 5. It will be seen that the outer and rear edge faces 19, 20 of projection 8 consist of level planes which, when the coupling devices engage one another, abut corresponding faces 19', 20' in recess 9. The outer and rear edge faces 19, 20 of the projection must in this case be designed in such a way as to ensure that, during mutual rotation of the coupling devices 6 about the fulcrum in corner 2| between step 15 and the inclined face 16, they do not come into contact with the inner face of the recess before the last phase of the said mutual rotary movement when the coupling devices are caused to engage one another. As a result no sliding friction arises between the various components of the coupling devices during the actual insertion and swinging operation which takes place when two U-shaped sections are to be coupled. This is an important advantage by comparison with insertion and swinging type coupling devices where the projection and the recess have complementary semi-circular cross-sections and where the semicircular faces slide on one another during the above mutual swinging motion.

If long U-sections having e.g. a length of 5 - 6 m and used to construct a loading platform are to be joined in the above manner it will be possible, with coupling devices of the latter type, for very large frictional forces to occur at the mating semi-circular faces, which will be apt to make the assembly of the U-sections difficult, and in the worst case may entirely prevent the above swinging movement owing to possible inaccuracies such as may occur when extruding long sections of this type.

By designing the coupling sections 5 as shown in figure 1 the above disadvantage is largely eliminated since the projection 8 has only two mating faces, i.e. the outer and rear edge faces 19, 20, which form parts of a circular cylindrical face. With this design it is possible to insert, when coupling the sections, the projection into the recess at a certain angle to the latter, whereafter the final swing of the coupling devices in relation to one another takes places with relative ease since friction, if any, arises only between the said edge faces 19, 20 and the cylindrical face of the recess. The said friction between faces 19, 20 of projection 8 and the circular face of recess 9 is entirely eliminated in the alternative embodiment of coupling devices 5 shown in figure 2 and discussed above.

When a torsionally rigid loading platform of the type discussed above is mounted on a moving e.g. on uneven ground such as a building site, the loading platform will be exposed to torsional stresses since the loading platform mountings in the chassis of the vehicle will be subject to a certain relative movement owing to the said torsional stresses. In such a case it may be advantageous to permit a certain torsion of the loading platform itself, which can be achieved by making the holes 13, 14 in the U-shaped sections somewhat larger than the diameter of the pins or bolts used. This enables a certain relative mobility between the U-shaped sections in their longitudinal direction whereby the loading platform follows to a certain extent possible distortions of the vehicle chassis when driving on uneven ground.

The above can also have some significance if the loading platform according to the invention is used as a tilting platform, with the platform secured to the chassis of the vehicle by means of four hinges capable of disengagement, so as to enable tilting to either side and to the rear, depending on which hinges are removed.

If the vehicle stands on uneven ground with its chassis somewhat distorted, the loading platform will, if it is entirely torsionally rigid and once two hinges have been removed, be supported only at three of the hinge points since owing to the said distortion of the vehicle chassis the loading platform will be lifted from the fourth hinge point. If one now changes one's mind and decides not to proceed with the tilting, the fourth hinge cannot be secured since owing to the said distortion the half hinges are at a distance from one another. In such a case the vehicle must be driven on to even ground so that the half hinges of the fourth hinge are brought together whereupon the hinge pin can be inserted.

If the loading platform is so designed that it can be torsionally deformed to some extent as described above the loading platform will in the latter case retain its torsional deformation since the U-shaped sections will have moved slightly in relation to one another without the half hinges of the fourth hinge separating. In this case it will again be possible to secure the hinge without having to drive the vehicle on to level ground.

Claims

Patent Claims

1. A load-bearing, torsionally rigid metal platform, preferably a loading platform for vehicles, consisting of laterally adjacent metal sections, preferably extruded Al-sections, provided with cooperating longitudinal coupling devices, c h ar act e r i s e d in that the sections (1) have a U-shaped cross-section comprising two parallel flanges (2, 3) and an intermediate web (4) and are, with the aid of the said coupling devices (5, 6) coupled together with the opening of one section facing web (4) of the other section so as to produce parallel, closed channels (7) of as such known type and where the upper and lower flanges of the sections (2, 3) constitute upper and lower faces of the platform extending in the longitudinal direction of the platform, and that the coupling devices (5) of the upper flange (2) of section (1) consist of a projection (8) at the free edge of the flange which is at a lower level in relation to the upper face of flange (2) so as to form a step (15) with the inclined face (16) and of a recess (9) at the base of flange (2) co-operating with projection (8), the said recess (9) consisting of a groove open towards the top, with a projection (17) at the base of flange (2) and at the same level as the latter projects inward over the opening of the groove since edge (18) of projection (17) is at an angle to the inclined face (16), and that the outer and rear edge faces (19, 20) of projection (8) abut mating faces (19', 20') in groove 9 when the coupling devices (5) are swung so as to engage one another about an axis of rotation located at the corner (21 ) between step (15) and inclined face (16) and that the coupling devicess (6) of the lower flange (3) of the section consist of as such known snapping devices comprising a bead (10) on the inside of the flange at the free edge of the latter and a complementary recess (1) at the base of the flange the said snapping devices (10, 11 ) being secured in as such known manner when the sections are coupled, with the aid of e.g. bolts, pins etc. (12) arranged in aligned holes (13, 14) in beads (10) and recesses (11), respectively.

2. A load-bearing, torsionally rigid metal platform in accordance with claim 1 , c h a r a c t e r i s e d i n that the recess (9) is supported at its outer half hy web (4).

3. A load-bearing torsionally rigid metal platform in accordance with claim 1, ch ar ac t e r i s e d i n that the recess (9) is supported at its centre part by web (4).

4. A load-bearing torsionally rigid metal platform in accordance with claim 1, ch ar ac t e ri s e d in that the recess (9) has a semi-circular cross-section and that the projection (17) protrudes halfways inwards over the opening of the groove, such that the lower limit of edge face (18) of projection (17) is located at the centre of the projection's semi-circular form and that the outer and read edge faces (19_> 20) of projection (8) form parts of a circular cylindrical face with its central axis in corner (21 ) between step (15) and inclined face (16) and with its diameter complementary fo the semi-circular shape of recess (9).

5. A load-bearing torsionally rigid metal platform in accordance with claim 1, ch ar a c t eri s e d i n that the diameters of holes (13, 14) are larger than the diameters of the bolts, pins etc. used so as to permit a certain distortion of the metal platform when the latter is subjected to torsional stresses.