TECHNICAL FIELD

The present invention relates to a spread unit for spreading granular material . In particular, the present invention relates to a spread unit for spreading anti- icing granular material to be distributed on extended surfaces such as, e.g., pavings in general, street surfaces, parking lots, harbour and airport areas, to which ^ the following disclosure will explicitly refer without however being less general.

BACKGROUND ART

The use of spread units is known for spreading anti-icing granular material, each comprising a hopper container, accommodating a mass of such material and having a lower opening, a spread device and a feed conveyor adapted to receive the material flowing out from said opening and to move it towards the spread device.

The known units of the above-described type are not very satisfactory, especially concerning the distribution uniformity of the anti-icing material.

The above disclosure is essentially attributable to the particular embodiment of known feed conveyors, which discontinuously feed the material, in some cases, due to the friction that is generated between the material and the fixed parts of the conveyor and, in other cases, due to the inevitable deformation of components of the conveyor itself under the weight of the material in the container.

Moreover, in both cases, many of the parts forming the conveyors wear out in relatively short time.

DISCLOSURE OF INVENTION

The object of the present invention is to make a spread unit, which allows the above-mentioned problems to be solved in a simple and cost-effective manner.

According to the present invention, a spread unit is made for spreading granular material; the unit comprising a collection compartment for said granular material, a lower outlet opening for the exit of the granular material from said collection compartment, conveying means adapted to receive said granular material flowing out from said lower outlet opening and feed it in a longitudinal direction; said conveying means comprising a fixed support surface arranged below said compartment and in a position facing said outlet opening to support the material contained in said compartment, transporting means to feed the material arranged on said fixed support surface in said longitudinal direction, and belt dosing means arranged downstream of the fixed support surface and of said opening in said longitudinal direction and adapted to receive the material arranged on said fixed support surface .

Preferably, in the above-mentioned unit, said dosing means comprise a mobile transport surface movable in said longitudinal direction and is substantially coplanar with said fixed support surface; said conveying means moving said material on said mobile transport surface.

Preferably, said transport means and said mobile surface also translate in said longitudinal direction at the same translation speed.

BRIEF DESCRIPTION OF THE DRAWING

The invention will now be described with reference to the accompanying drawing, which shows a perspective view having parts removed for clarity of a preferred, non- limiting embodiment of a spread unit for spreading granular material made according to the dictates of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

In the accompanying figure, numeral 1 indicates a spread unit for spreading granular material as a whole, such as for example an anti-icing saline substance, on an extended surface 2 such as e.g. a paving in general, a street surface, a parking lot, a harbour or airport area, etc.

The unit comprises a frame 3 adapted to be connected, for example to a self-propelled unit 4 (partially shown) , and a container 5 for the granular material and supported by frame 3.

Container 5 comprises a front frontal wall 6, a rear frontal wall 7 and two side walls 8 (only one of which is seen in the accompanying drawing) , which converge towards each other and downwards to define, with the frontal walls 6, 7, an outlet 9 which is elongated in a longitudinal direction A.

Again with reference to the accompanying figure 1, unit 1 also comprises a disk spreader 10, in itself known and not described in detail, for distributing the granular material over the above-mentioned extended surface 2, and a conveyor and dosing assembly 11 for feeding the material in the longitudinal direction A and generating a homogeneous and continuous flow of material towards spreader 10.

The conveyor and dosing assembly 11 comprises a blade conveyor 12, which extends in a facing position and basically for the entire length of opening 9, for supporting - without deforming it - the material housed in container 5 and gradually flowing out from opening 9, and a belt dosing device 13 arranged downstream of conveyor 12 in the material feed direction A and on the side of opening 9, for receiving the material from the blade conveyor 12 and sending it to spreader 10.

The blade conveyor 12 comprises a flat rigid wall 14 facing opening 9 and stably connected to frame 3 so as to close opening 9, and a blade catenary 15 for translating the granular material deposited on wall 14 in the longitudinal direction A.

Catenary 15 comprises two drag chains 16, which are transversally distanced from each other and are wound ringwise on end roller deviating bodies 16, 18 having respective toothed mesh pulleys of the respective drag chains 16. The pulleys are keyed onto end sections of respective shafts 16a, 18a, which are arranged at longitudinal parts opposite to wall 14 and rotatably about respective axes 16b and 18b, which are parallel to each other and to wall 14 and are orthogonal to direction A.

In the particular embodiment described, shaft 16a is motorised and is arranged downstream of the frontal wall 7 in an inlet 10a of spreader 10.

Catenary 15 further comprises a plurality of blades 19, which are orthogonal and integrally connected to the chains 16 to slidingly cooperate with the upper surface 14a of wall 14 and feed the material past the frontal wall 7 through an opening or passageway 20 obtained in the frontal wall 7.

Again with reference to the accompanying figure, the dosing device 13 comprises a flexible belt 21, which is conveniently made of polymeric or other similar material, which is wound ringwise about a longitudinal pair of end deviating rollers 23 and 24, which are parallel to each other and to the axes 16b, 18b of the shafts 16, 18. Of the rollers 23 and 24, roller 23 is keyed onto the intermediate section of shaft 16a between the related toothed pulleys, while roller 24 is arranged below and substantially at the frontal wall 7 or at passageway 20. The rollers 23 and 24 divide belt 21 into a delivery branch 21a and a return branch 21b; the delivery branch 21a is substantially coplanar to the upper surface 14a of wall 14, to which it is conveniently joined by a plate portion 26, and is arranged tangent to blade 19 to define, with the blades 19, some pockets 27 housing predefined masses of material.

Since catenary 15 and belt 21 are coupled to the same shaft 16a in angularly fixed positions, the , delivery branch 21a and the blades 19 translate in direction A at the same speed whereby the related speed is null between the delivery branch 21 and the blades 19, and the volume of pockets 27 is constant.

According to a variant not shown, catenary 15 is not coupled to shaft 16a but is wound about a motorised return shaft of it, again parallel to shaft 18 and arranged upstream of roller 24 and independent from roller 24. Therefore, catenary 15 and belt 21 of the dosing device 13 may be controlled independently from each other, so as to feed the material at different speeds in direction A, depending on the position of the material .

Again with reference to the accompanying figure, the dosing device 13 also comprises a crushing assembly 29 arranged in a position facing the delivery branch 21a of belt 21, for crushing the material being fed in conjunction with belt 21 and arranged between the blades 19.

It is apparent from the above that the particular embodiment of the described conveyor assembly 12 allows, the material contained in container 5 to be fed, but especially accurately dosed, whatever the level of the material inside container 5 and, therefore, a continuous and uniform flow to be sent towards inlet 10a of spreader 10.

The above is essentially subsequent to the fact that the weight of the material housed inside container 5 is basically only supported by the rigid wall 14 arranged below outlet 9 of container 5, while the dosing device 13, which extends past the outlet opening 9 of container 5 supports definitely less weight with respect to: the one supported by the fixed wall 14, and specifically, only the weight of the material fed by catenary 15.

It should also be noted that the weight supported by the dosing device 13 does not vary as the quantity of material housed in container 5 varies, thus the material is always fed under the same load or stress conditions and this, associated -with the lack of related motion with catenary 15, makes it possible to feed a constant flow of material.

In view of the above-mentioned reasons, it is then possible to make a belt 21 and hence a dosing device 13 having an extremely contained longitudinal, length with respect to the blade conveyor and hence a unit having an overall longitudinal size which is comparable with the one of known embodiments and, therefore, usable on existing vehicles without the need for structural modifications to be made to the vehicles themselves.

From the above it is apparent that modifications or variants may be made to described unit 1, without departing from the scope of protection defined by the independent claim.

In particular, the blade conveyor or the dosing device 13, of which belt 21 may be made with materials other than the one described, may be constructionally different from the ones described by way of example.

Spreader 10 may also be different from the one described.