It is known in the art to mix the ingredients of concrete so as to obtain a pourable and curable concrete mixture. Most common- ly the ingredients are premixed in a factory and then transported to the construction site. A huge disadvantage of this method is that high costs are involved for transporting the total amount re quired for a job, since the total required amount is always trans ported in at least two rides so as to ensure that the total amount required for the job is delivered as closely as possible. Hence, even when the total amount required is less than can be transport ed in a single ride, still two rides are applied. Transport costs thus comprise a considerable part of the total costs involved for delivering concrete to a construction site.

An unsatisfactory solution consists of a so-called volume mixer, comprising an integrated concrete mixer wherein ingredients are mixed manually to produce a curable concrete mixture.

A disadvantage of this known vehicle is its unsuitability for accurate measuring of the ingredients. As a result, both the exact composition of the concrete mixture and the total amount thereof cannot be predicted or ensured.

The invention aims at providing an improved vehicle of the kind mentioned in the preamble.

The invention further aims at providing a vehicle that allows to accurately predict the amount of concrete produced.

The invention also aims at providing a vehicle that allows for an exact composition of the concrete mixture produced.

Furthermore, the invention aims at providing a vehicle making it no longer necessary to apply at least two rides when delivering a curable concrete at a construction site.

So as to obtain at least one of the above mentioned aims, the invention provides a vehicle as mentioned in claim 1. This vehicle has the advantage that the amounts of individual ingredients can be weighed accurately thus producing a concrete mixture that ex actly matches the recipe.

It has also shown that the vehicle according to the present invention saves costs. For, the vehicle can take more ingredients than are absolutely required for a specific job, to the construc tions site. Then, the exact amount of concrete required for the job is produced. The remaining ingredients can be kept in the ve hicle for another job. More in particular, the vehicle can drive to another job directly after finishing the present job without the need to firstly go to a premix factory as is necessary accord ing to the state of the art, even when the next job requires a different concrete composition. Furthermore, unlike concrete manu factured in a factory, no waste remains. Such synergistic effect is a surprising and advantageous effect.

The invention therefore relates to a vehicle for producing a curable concrete mixture, comprising a vehicle chassis with transport means and ingredient containers for containing concrete ingredients, wherein the ingredient containers are suspended by means of load cells. This vehicle has the advantage that the amount of the ingredients are exactly known when they are removed from the ingredient containers for producing the concrete mixture. Since load cells allow an automated dosing of the ingredients, as known to a person skilled in dosing techniques, the vehicle ac- cording to the present invention provides significant advantage compared to the available state of the art.

Preferably, the vehicle comprises a frame carried by said chassis, wherein the ingredient containers are suspended with re spect to the frame by means of load cells. Such embodiment pro- vides advantage in that the frame can be developed such that every load cell has an optimum position with respect to the item that has to be weighed, for example each ingredient container.

As a matter of fact, the load cells are preferably connected to a central processing unit for providing a signal depending on the load exerted by the container and optional ingredients there in, for calculating a weight of said container and said optional ingredients. Such centrally processed information thus can be used for determining how much ingredient is removed from the container to, for example, a mixer for mixing said ingredient with other in gredients. The central processor may be used for dosing and mixing said several ingredients in an automated way.

A simple embodiment is obtained with a vehicle comprising a frame with a bottom side near the vehicle' s chassis and a top side away from said chassis, the ingredient containers being suspended from the frame's top side.

According to a further preferred embodiment of the vehicle according to the present invention, said vehicle having a bottom side near the vehicle's chassis, transport means for ingredients derived from any of the ingredient containers are provided at the vehicle's bottom side. Such allows the ingredients to be simply removed from the containers into or onto the transport means by gravity. In the present invention, the transport means may for ex ample consist of a conveyor type transporter for transporting the ingredients from the container towards a mixer for mixing ingredi ents received from multiple containers.

It is also preferred in the vehicle according to the present invention that the transport means are suspended by means of load cells. This allows for an additional weighing of the ingredients. For example, the load cells weighing the transport means may have an optimum weighing range that is less than that of the ingredient containers, allowing for a more accurate weighing of the ingredi- ents in the transport means. In addition, the mixing means may have load cells as well, so as to be able to perform a weighing of the mixing means both during mixing and after removing said contents of the mixing means after transferring the contents (the curable concrete mixture) to the construction site.

Analogously to the ingredient container, it is also preferred that the vehicle comprising a frame carried by said chassis, wherein the transport means are suspended with respect to the frame by means of load cells. The same advantage is obtained as indicated above with respect to the ingredient container.

In addition to that embodiment, it is preferred that the transport means are suspended independently from the ingredient containers . Such embodiment allows for an accurate measurement of the amounts of ingredients removed from the ingredient container and into the transport means. Thus, a very accurate composition of the curable concrete mixture is obtained.

As indicated above, it is preferred that the vehicle also comprises mixing means for mixing ingredients from at least two ingredient containers. As a consequence, a complete curable mix ture can be produced that can be used as such at a construction site. After driving the vehicle to the constructions site the re quired amount of curable concrete can be produced at the construc- tion site and applied as required in an exact amount. Additional rides therefore are not required.

It is, analogous, to the ingredient container and the transport means, preferred that the mixing means in the vehicle according to the invention are suspended by means of load cells, preferably suspended by means of load cells with respect to a frame connected to the vehicle's chassis. Such allows for an exact weighing of ingredients and a possibility to check if all ingredi ents as dosed from the container into the transport means are ac tually received by the mixing means, as well as the possibility to exactly weigh the amount of curable concrete available in the mix ing means and added to the construction site.

Since the ingredients should not be influenced by weather, and neither the weight of the contents of the containers, it is preferred that the vehicle according to the present invention com- prises a cover at its top side. The ingredients thus keep dry, adding to a correct amount of ingredients when composing a con crete mixture. Also, the cement maintains its intended character istics .

According to another embodiment, the present invention re- lates to a method for loading a vehicle as mentioned above, the method comprising the steps of positioning the vehicle on a weigh bridge, and weighing the vehicle before and after adding an ingre dient to an ingredient container, to determine the amount of in gredients added to said ingredient container. This adds an addi- tional certainty in the amount of ingredients loaded into the ve hicle' s ingredient containers, in addition to the weight obtained from the information provided by the load cells weighing the con- tainers .

In such method, it is especially preferred that adding the ingredients to the ingredients containers is performed as fast as possible so as to save time. In that case, since ingredients that are added to an ingredients container may comprise more than a single component, the method may comprise the step of loading an ingredient container with a premixed composition of ingredients. The loading station were the vehicle is loaded may be a so-called intelligent loading station weighing the components in a correct amount and composition and adding same to the ingredient container of the vehicle.

According to a still further embodiment, the present inven tion relates to a method of use of a vehicle according to the in vention as described above, comprising the steps of removing in- gredients from at least one container onto a transport means while weighing said at least one container and said transport means.

Such method applying a double weighing procedure adds in an accu rate mixing of ingredients and a curable concrete mixture that ex actly fulfils the recipe.

In addition to the step of weighing at the transport means, it is preferred even more that the method comprises the steps of removing at least cement, aggregates and water from ingredient containers and mixing same. Other ingredients may be added, like superplasticizer and a multiplicity of aggregates, like sand, peb- bles and gravel in any kind and amount useful the concrete mix ture .

Finally, in the method according to the invention it is pre ferred that it comprises the step of mixing said ingredients by means of a mixer provided on the vehicle, yielding an easy way to produce a curable concrete mixture.

Hereafter, the invention will be further described by means of a drawing. The drawing shows in:

Fig. 1 a view of part of a vehicle according to the present invention.

For ease of understanding the figure, not all parts that are required for a practical embodiment have been shown. Fig. 1 shows a perspective view of a part of a vehicle for producing a curable concrete mixture. More in particular, the drawing shows a frame 1 to which ingredient containers 2, 3, 4, 5, 6 for containing concrete ingredients and transport means 7, 8 are connected. The ingredient containers 2, 3, 4, 5, 6 are suspended by means of load cells 9.

For example, ingredient container 4 may comprise Portland ce ment, whereas containers 5 and 6 may contain fly ash and blast furnace cement, respectively. It will be clear to a skilled person that these contents are exemplary only and not limiting to the in vention. The containers may comprise other ingredients, depending on the concrete to be manufactured. Furthermore, containers 2 and 3 may for example contain sand and water, respectively.

In the non-limiting embodiment of Fig. 1, the frame 1 con sists of uprights 10 and horizontal beams 11, as well as a few slanting beams 12. As a result, a stiff and safe constructions is obtained, suitable for carrying the ingredient containers 2, 3, 4, 5, 6 and their contents as well as transport 7, 8 and mixing means 13.

Ingredients are removed from the ingredient containers 2, 3, 4, 5, 6 onto a transport means 7, 8 through openings at a bottom of the containers. The containers are provided with a controllable output valve (not shown) that preferably is controlled by a cen tral processing unit. The central processing unit also preferably receives data from the load cells such that it is fed with data regarding the amount of ingredient removed from each container and the time each output valve is opened. The central processing unit therefore is able to accurately determine the amount of each in gredient removed from the containers. The transport means 7 transport the ingredients to a mixer. The mixer may be a batch- type mixer or a continuous mixer. An unexpected effect of the pre sent invention, more in particular of the fact that load cells are provided at the transport means and at the individual containers and that a central processing unit is used for controlling the containers, transport means and mixer, is that a continuous mixer can be used for producing a continuous curable concrete mixture at a continuous high quality that exactly meets preprogrammed speci- fications. The continuous high quality is novel in the art.

The ingredients from the several ingredient containers are mixed by a mixer 13. The mixer is positioned at an end section of the vehicle. After leaving the mixer 13, the ingredients are transported through an auger 14, optionally comprising paddles or the like static mixing means, for additional mixing so as to main tain an optimum mixture that is delivered in an optimum condition to the construction site.

The invention also relates to all combinations of features described here independently of each other.

The invention is not limited to the embodiments as mentioned above and as shown in the drawing. The invention is limited by the claims only.