The object of the invention is a tank construction in a bulk cargo transportation system consisting of a lorry and trailer, in which revolving cylindrical tanks equipped with parallel interior spirals are supported longitudinally on the chassis of the lorry and trailer, the tanks including opposite cones with openings, the first cone being longer having a greater reduction when compared to the other, and in which system the tanks are arranged to be placed one after the other by pushing the long cone of the first tank into the larger opening of the second tank in which case by rotating the tanks the mass of the cargo moves from the first tank to the second one.

For simplicity and clarity a bulk cargo of concrete and its handling is referred to in this application, but the tank construction and method in accordance with the invention can equally well be applied to the transportation, mixing, preparation and storage of other kinds of bulk cargoes. Other bulk cargoes of this kind can be, for example, liquid bulk cargoes, grain, fertilizer, feedstuffs, sand, crushed rock, salt, and cement. Here the cone and end of the cone forming part of the tank refers more precisely to truncated cones, in which the point of truncation generally forms the opening of the tank. The forms of the ends of the cones may also deviate from an exactly geometrical conical surface.

Nowadays concrete is mainly made in separate concrete sta- tions, from which it is transported ready-made by road to the point of use. At the point of use the concrete is either transferred directly to the casting place or else to a suitable storage silo, from which it is used gradually.

One problem with the present system is that only relatively small amounts of concrete can be brought by road, lorries cannot be used for the longer term storage of ready-mixed or dry concrete, because on account of their cost they must be

continuously in use and when using the present storage facilities at working sites the more varied handling and preparation of bulk concrete is not possible.

Tank car systems applicable to railway use, in which rotatable tanks are connected to one another longitudinally, are known from patent publications US 3,567,190, CH 497,961, and EP 240594. In these each tank has a pointed funnel at one end, which is pushed into the next tank through a larger opening. When each tank is rotated, the bulk cargo is pushed into the next tank by an internal spiral, provided the direction of rotation is correct. In road vehicle use, particularly in concrete distribution, systems of this kind are of very little use. In particular the tank on the lorry cannot be filled and emptied by means of the through-flow system, because there is no empty space in front of the tank for the opening. Tanks must be able to be filled by other principles than the aforementioned through- low principle. In general, in road vehicle use considerably more varied use is demanded than is possible with the tank systems presented in the aforementioned publications.

The intention of the invention is to remove the aforementioned problems and to show a new tank construction that permits varied methods of handling the bulk cargo, it is easily emptied and filled and in this way is very well suited to the temporary storage and preparation of bulk concrete.

The characteristic features of the invention are referred to in the Patent Claims.

The tank construction to be situated on the lorry or trailer includes a cylindrical rotatable tank with a horizontal axis. One end of the tank has a conical form on the end of which is a filling/emptying opening, the tank being essentially additionally equipped with an internal spiral that extends from end to end of the tank to mix the mass within and to empty and fill the tank. In accordance with the invention, the

filling/emptying opening in the conical end includes a pipe¬ like interchangeable point, advantageously made as a conical cover, the broader end of which is dimensioned such that it fits the conical end the narrower end of the interchangeable point being essentially smaller than the filling/emptying opening.

Advantageously the trailer tank is arranged as a through-flow tank in such a way that there are conical ends at both ends of it, which act as filling and emptying openings always depending on the direction of rotation, because as the tank rotates the spiral running round the inside mixes the mass in the tank and directs the mass to one or other end of the tank, depending on the direction of rotation of the tank.

Advantageously an interchangeable point in accordance with the invention includes suitable locking elements and the conical end includes counter-elements, in which case the interchangeable point can be locked to the conical end in order to rotate with the tank structure. Suitable bolts, hinges, hooks, or other locking devices may be used as locking elements and counter elements. What is essential is that the interchangeable point is made to remain in place as an extension of the filling/emptying opening when the tank revolves and the mass flows through the interchangeable points. Inside the interchangeable points a spiral construction is arranged to correspond to that in the tank, in which case when the tank is being emptied liquid can also flow efficiently out of the opening of the interchangeable points.

In one adaptation of the invention, a jointed funnel component is arranged at at least one end of the tank structure for filling the tank when the interchangeable point is not in place. On the other hand, the funnel component acts as a shut- off element, against which the concrete mass for example, can be mixed.

A suitable cover, by means of which the filling/emptying opening of the conical end can be absolutely tightly closed, can also be used as a shut-off element.

Because the chassis of the lorry and trailer have suspension, it is advantageous if there are locating elements between them to keep the opposing conical ends at the same height.

An advantage of the invention when compared with known tech- niques is that it makes it possible to handle the bulk cargo in various ways. By means of the tank construction large amounts of bulk cargo can be transported, it is easy to use, to fill, and to empty, it can be used as a temporary store for various kinds of bulk cargo and it is easy to use in restricted spaces such as building sites, mines, and similar places.

In what follows the invention is explained in detail by referring to the accompanying illustrations, in which one tank structure in accordance with the invention is shown.

Figure 1 shows a tank trailer and the rear end of the lorry Figure 2 shows a trailer and the use of its tank when transferring a bulk cargo Figure 3 shows a trailer tank seen from in front

The first tank structure is formed by a cylindrical tank 3 which is supported by bearings and is able to rotate on top of the chassis 2 of a trailer 1, both ends 4, 5 of which tank have conical ends 6, 7 and a flange 8 that surrounds the filling/emptying openings at their points. Spiral 9 runs from end to end inside the tank.

An interchangeable point 10 consisting of a conical cover is attached by means of a locking element 11 to the flange 8 of the conical end 6 of the other end 4 of the tank. A spiral 18 is arranged inside the interchangeable point 10 as a corresponding continuation of spiral 9. Interchangeable point

10 can also be alternatively attached to flange 8 of the conical end 7 of the other end 5 of the tank structure. This is, however, an unusual method of use. It is much more usual to have to attach the interchangeable point 10 to the corresponding conical end 15 of the lorry, which is explained later in greater detail.

In the case shown in the drawing the rear end 3 of the tank is closed with the filling funnel 12, which is supported by an arm resting on the articulated chassis 2 and is operated by means of a hydraulic cylinder 13. The filling funnel 12 includes a rubber gasket that presses against flange 8, and permits their mutual rotation.

When end 5 is closed by the filling funnel 12 tank 3 can be rotated in such a way that the mass inside it presses against the filling funnel 12 and thus the mass can be mixed, thus possibly preventing it from hardening too soon. When it is wished to remove the mass from the tank the direction of rotation is reversed, when the mass discharges through the interchangeable point 10 or by raising the filling funnel 12, when the mass is made to discharge into the lower funnel 14, to which a channel can be attached to direct the mass.

The conical end 15 of the tank 19 of lorry 16 also has available a lower funnel 14 and filling funnel 12 as well as its operating cylinder 13, the manner of use of which is the same as in trailer 1.

The front of the chassis of trailer 1 includes a pin 23, which forms, together with the guide collar 24 situated at the rear of the chassis of the lorry 16, locating elements to keep the conical ends 6 and 15 on the same line. The penetrating interchangeable point 10 of the conical end 15 then rotates centrally. This situation is shown in Figure 2. Here the filling funnel 12 is first raised, after which the lorry 16 can reserve to connect with the trailer 1. In this way the

lorry 16 can fetch concrete from the trailer 1, which cannot be driven right up to the building site.

Interchangeable point 10 includes a rubber flange gasket 22, which during the transfer operation is pressed against flange 17 of the conical end 15. This prevents completely any leak of the concrete mass. Usually the mass does not try to leak, if both tanks are rotated.

It is extremely important that the interior spirals 9 of the tanks 3 and 9 extend up to the flanges 8, even though they are reduced in height at the ends, and that the interchangeable point 10 also includes a spiral 18. By means of this, liquids, especially tank washing water are emptied completely.

It is often advantageous at work sites if trailer 1 can be left at the building site as a temporary store. The inter¬ changeable point 10 must then be turned and attached to the tank 19 of the lorry 16, by means of which tank 3 of trailer 1 can be filled. By using existing equipment tank 19 of the lorry 16 can be emptied into tank 3 in only 6 minutes, which allows great efficiency in the trips of the lorry 1.

The front of the chassis of the trailer 2 includes an in- terchangeable point lifting and locating device 21, which is shown in greater detail in Figure 3. Lifting arm 26 is sup¬ ported by vertical beam 25 around which it runs and up which it is raised. Turning support 27, by means of which the interchangeable point 10 can be supported while turning is further jointed to this around the vertical axis.

Above the invention is described in detail by referring to one advantageous structural solution. The various adaptations of the invention can, however, be varied in accordance with the inventive idea delimited by the accompanying Patent Claims.