DESCRIPTION

Technical field

The invention relates to a centrifugal distributor for granular products such as fertilizers and the like and a deflector for a centrifugal distributor. Such distributors are better known in the agricultural field by the term "centrifugal spreader"; both terms will be used interchangeably in the following description. Technological background

These distributors are generally fitted with one or two discs which are provided with a set of launching blades and which are rotated at high speed about a respective vertical axis. The product to be distributed is dispensed in a metered manner and can be adjusted at each disc in order to be launched in a broadcast manner as a result of the centrifugal force applied to the granules. The deflector is mainly used to distribute granular products at the field border, limiting and preferably avoiding the scattering of product beyond the confines of the field.

The central deflectors (that is to say, ones intended for double-disc distributors) currently commercially available are produced from two screens which, when they are brought into an operating position, that is to say, positioned between the two discs, partially wrap around the scattering discs. The operator, where applicable, lowers the two screens so as to partially intercept the fertilizer launched by the discs.

The mechanism which allows the deflector to be raised and lowered towards and away from the operating position is generally constructed with an articulated parallelogram system or with a hinge type movement system.

In accordance with the type of fertilizer, the working width and the distance from the border, it becomes necessary to adjust the deflector by modifying the position and/or the formation of the two screens so as to increase or decrease the portion of fertilizer intercepted and deflected.

Different adjustment systems are typically used to this end. An example is brought about by extending or shortening the extent of the screens so as to enclose a sector of the launching circumference to a greater or lesser extent. Alternatively, the screens are provided with end flaps, the position of which with respect to a fixed portion of the respective screen is adjustable.

W02016/108196A1 describes a deflector group comprising a support frame, to which there are connected fixed deflector fins and adjustable deflector fins. The fixed deflector fins are rigidly connected to the support frame while the adjustable deflector fins are fixed in rotation to the support frame. A control plate is movable with respect to the support frame in a translation direction in order to control the rotation of the adjustable deflector fins.

In another known solution, the two screens are connected to each other so as to be able to freely vary the angle between them.

Finally, there is also known a central deflector which is formed by two channellike screens, inside which a movable adjustment flap is placed.

Therefore, all these known systems are based on a rotation of the deflector screens or a translational movement thereof. They have one or more of the following disadvantages. Firstly, they very often involve undesirable dimensions and projections in the rear portion of the distributor, including as a result of the fact that the adjustment path of the movable portions of the screens has to be relatively high in order to be able to provide a significant and effective adjustment. In some cases, this makes it necessary for the deflector to be able to be positioned in a non-operating position (for example, inverted with respect to the operating position) so as to require a substantial operation in order to bring it into operation. Furthermore, these systems are not suitable for remote adjustment which can be carried out by means of actuators. Finally, the adjustment which can be obtained is imprecise and not accurate.

Description of the invention

An objective of the invention is to provide a centrifugal distributor for granular products, such as fertilizers and the like, which is structurally and functionally configured to at least partially overcome one or more of the disadvantages set out with reference to the cited prior art. A primary object of the invention is to provide a distributor of the type mentioned above which allows accurate adjustment of the throttling control at the field border. Furthermore, an object of the invention is to be able to automate this adjustment by means of actuators. In a first aspect thereof, therefore, the present invention refers to a centrifugal distributor for granular products, such as fertilizers and the like, comprising:

- at least one distributor disc which is rotated about a vertical axis and which is provided with a set of launching blades for the granular product,

- a deflector for distribution at the field border which is movable away from and towards an operating position,

- the deflector advantageously comprises for each disc a respective screen which is arranged, in the operating position, closely behind a circumferential portion of the respective disc at the exterior of the path of the set of launching blades in order to intercept the launch path of the granular product at the circumferential portion and/or to redirect it in accordance with a deflected launch path. Preferably, the screen includes a movable set of blades but even more preferably it includes a fixed set of blades and at least one movable set of blades which can be adjusted with respect to the fixed set of blades in order to vary the deflected launch path. In one aspect of the invention, the movable set of blades of each screen can be positioned with respect to the deflector and in particular with respect to the corresponding fixed set of blades in accordance with a roto-translational adjustment path.

In a second aspect of the invention, the deflector comprises at least a first plate and a second plate which are connected in a guided manner in order to move one in translation with respect to the other. Preferably, the movable set of blades is secured to both the plates in at least two spaced-apart locations by means of a respective pin. In a preferred embodiment, each pin is engaged in pairs of first and second channels which are formed in the plates and define incident and intersecting cam profiles so as to define a unique position for each pin as the relative position of the first plate varies with respect to the second plate.

Brief descriotion of the drawings

The features and advantages of the invention will be better appreciated from the following detailed description of a preferred though non-limiting embodiment thereof which is illustrated by way of non-limiting example with reference to the appended drawings, in which:

- Figure 1 is a perspective view of a detail of a centrifugal distributor according to the invention;

- Figure 2 is a schematic plan view of the distributor of Figure 1 adjusted for distribution in an open field; - Figure 3 is a schematic plan view of the distributor of Figure 1 adjusted for distribution at a field border;

- Figures 4A, B and 5A, B are schematic views of a detail of the distributor of the preceding Figures and the respective position of the fixed and movable set of blades thereof in two different adjustment positions;

- Figures 6, 6A and 7, 7A are perspective views of a detail of the distributor of the preceding Figures and the respective position of the fixed and movable set of blades thereof in two different adjustment positions.

Preferred embodiments of the invention

In the Figures, there is generally designated 10 a centrifugal distributor for granular products including a pair of discs 1, 2 which are each provided with a respective set of launching blades 4. The discs are rotated in a counter- rotating manner (that is to say, with a direction counter to each other) about a respective vertical axis XI, X2 by a respective motorization system, for example, a gearbox, hydraulic motors or electric motors or the like.

There is provided between the discs a deflector device 3 which is constructed according to the present invention. The deflector 3 is movable away from and towards an operating position which is depicted in Figures 1, 2 and 3. When the deflector 3 is in a non-operating position, however, it is remote from the discs 1, 2 in such a position that the operation of the centrifugal distributor is not influenced thereby.

The movement between the two positions is obtained by means of an articulated parallelogram mechanism 11 with at least one pair of connecting rods 11a, b which are hinged, at one side, to a fixed support 12 and, at the opposite side, to a movable support 13. A linear actuator 14, such as an electrical, hydraulic or pneumatic actuator or an actuator with rotation, is used to move the parallelogram 11 away from and towards the operating position, for example, by controlling by means of a handle 16 the rotation of one of the pairs of connecting rods 11a, b with respect to the hinging location, respectively.

The fixed support is anchored to a frame 17 of the distributor while the movable support 13 is anchored to a first plate 18 of the deflector by means of, for example, screw type or bolt type connections 19. The first plate 18 is therefore fixed with respect to the movable support, drawing the entire deflector 3 during the movement away from and towards the operating position.

With reference to the embodiment of Figure 7, a second plate 20 is superimposed on the first plate 18 and is slidingly guided thereon, for example, by means of a set of guides which is formed by two or more channels 24 (four in the exemplary case in point), which are preferably rectilinear and parallel with respect to each other.

Respective guide pegs 25 which are fixed to the first plate 18 are slidingly engaged in the channels 24. It may be observed that the channels 24 are present at a rate of a pair for each disc. With reference to the embodiment of Figure 6, however, an additional channel 21 is engaged by a screw which can be manoeuvred by means of a knob 23 and which serves to frictional ly block by clamping the two plates on each other.

An additional plurality of channels 26a, b, c and 27a, b, c, the formation and progression of which will be better explained below, are formed in the first plate 18. It may be observed for the time being that in reality this involves two rows of three channels, which are curvilinear, one row for each disc, the first row having a specularly symmetrical progression with respect to the second row. A corresponding pair of rows of three channels 28a, b, c and 29a, b, c are arranged on the second plate 20. Corresponding channels, that is to say, ones relevant to the adjustment of the same disc and cooperating with each other in pairs, are denoted with the same indices a, b, c in relation to the pairs of channels 26 and 28 and the pairs 27 and 29.

These pairs of corresponding channels both receive the same guide roller or pin 30a, b, c and 31a, b, c which acts as a cam follower as indicated below.

With reference to the embodiment of Figure 7A, the guide pins 30a, b, c and 31a, b, c are fixed with a predetermined relative arrangement to respective directed elements which are formed by first brackets 32, to which there is further fixed a movable set of blades 33 of the deflector 3. The movable set of blades 33 preferably comprises two (or more) sections 33a, b which are preferably angled with respect to each other so as to define a concavity which faces the respective disc. It is further envisaged that these sections extend as a single curvilinear profile.

The deflector 3 further comprises a second bracket 35 which supports a fixed set of blades 36 which is also preferably in two sections 36a, b which are angled with respect to each other (or at the limit having a curvilinear profile) with concavity facing the respective disc.

The movable and the fixed sets of blades therefore constitute for each disc a respective screen which is generally designated 40 and which is arranged, when the deflector 3 is in an operating position, closely behind a circumferential portion of the respective disc outside the path of the set of launching blades in order to intercept the launch path of the granular product at the circumferential portion and/or to redirect it in accordance with a deflected launch path. The deflector 3 is used to distribute granular material near the field border B, as illustrated in the embodiment of Figure 3. While, under operating conditions in the open field, both the discs 1, 2 are supplied and carry out a scattering of the granular material with a launch sector S of approximately 180°, therefore intersecting in the superimposition zone, in the distribution at the field border B only a single scattering disc is supplied and the tractor which carries or pulls the distributor 10 is driven along the boundary of the field border B or a short distance therefrom, within the field involved. The supplied disc is the disc directed towards the interior of the field being worked. In this case, the deflector 3 constitutes a barrier which is able to intercept the launch sector S reducing it to approximately 90° in order to prevent the granular material which is distributed from becoming lost beyond the field border B.

The movable set of blades 33 can be moved with respect to the corresponding fixed set of blades 36 in order to vary the extent of the concerned launch sector S of each disc. The adjustment path is such as to vary in a decreasing or increasing manner the extent of the screen 40 in the direction of the circumferential portion of the launch sector S of the corresponding disc. Since the movable set of blades 33 is retained on the first plate 18 and second plate 20 by means of the respective first bracket 32 by using the pins 30a, b, c with both the respective corresponding channels 26a, 28a - 26b, 28b - 26c, 28c, respectively, this results in the movable set of blades, as a result of a linear translation of the plates 18, 20 one on the other and with a suitable profile of the channels, being able to be positioned with respect to the corresponding fixed set of blades 36 in accordance with a roto-translational adjustment path.

In order to promote the relative movement between the guide pins 30a, b, c and 31a, b, c and the respective pairs of channels and therefore to prevent blockages of the device, it is preferable for at least one pair of the corresponding channels which are engaged by the same pin and preferably a single pair of channels, to be engaged by the respective pin with a radial play which is less than the radial play between the respective other pins and the respective pairs of channels. In this manner, a single pair of channels and relevant pin bring about the relative movement of the movable set of blades 33 and the remaining pairs of channels and relevant pins are limited to acting as a support and positional constraint between the plates 18, 20.

In some embodiments, each set of guide pins 30a, b, c and 31a, b, c comprises a main pin which is designated 30b and 31b, respectively, and two secondary pins which are designated 30a, c and 31a, c, respectively.

Preferably, the secondary pins 30a, c and 31a, c only have the objective of supporting the deflector and guiding it in accordance with the channels of the first plate 18 to the extent that the channels of the second plate 20, in the region of the secondary pins, are preferably much wider than the respective pins. More particularly, the channels of the second plate 20 have such dimensions as to receive the respective secondary pins 30a, c and 31a, c with radial play greater than the radial play between the primary pins 30b and 31b and the respective pairs of channels.

While it is possible that all the pins and the respective pairs of channels contribute to guiding the movable set of blades 33, this solution is preferable because it limits the occurrences of friction and reduces the possibility of jamming during the adjustment of the movable sets of blades.

Since the relative translational movement of the first plate 18 and second plate 20 is linear, it is possible to obtain as a result of the formation of the channels, a roto-translational movement of the movable plates 33 with extreme efficiency of adjustment (the movable set of blades will intercept to a greater or lesser extent, in accordance with the adjustment imposed, the path of the set of launching blades) still with a relatively modest respective movement of the plates. This fact advantageously allows the dimensions of the deflector 3 to be limited and makes it possible for the actuation to be both manual and mechanized. In particular, with reference to the embodiment of Figure 6, it is possible to carry out the manual adjustment of the deflector, for example, by means of a handle 43 which is applied to an extension piece 42 of the second plate. Alternatively, with reference to the embodiment of Figure 7, it is possible to carry out the mechanized adjustment of the deflector, for example, by means of a linear actuator 41 which is interposed between a fixed portion of the deflector, for example, the first plate 18, and the extension piece 42.

It will be observed that the path of the channels 26, 27, 28 and 29 (a, b, c) is selected so as to obtain the maximum free opening possible by making the movable set of blades 33 carry out a movement so as not to strike, under any conditions, whether operating or non-operating conditions, the members of the distributor, particularly during the movement from the operating position to the non-operating position, and vice versa. The path of the channels, the extent thereof and the dimensions of the movable set of blades 33 is designed to ensure the possibility of adjusting the deflector even when it is in a nonoperating position.

Furthermore, the dimensions, position and path of the channels and the respective guide pins are selected so that the forces generated by the interference between the channels and the pins are orientated with such angles as to allow the movement of the deflectors and relevant sets of blades.

In this manner, the adjustment path is such as to vary in a decreasing or increasing manner the extent of the screen 40 in the direction of the circumferential portion of the corresponding disc, intercepting it to a lesser or greater degree, respectively.

The deflector 3 is adjustable because the discharge "range" of the fertilizer from the disc varies on the basis of the type of granular material distributed and the working width imposed on the machine. Therefore, in order to seek to minimize the quantity of fertilizer which leaves the field and at the same time to fertilize as far as the boundary of the field border B, in accordance with the working conditions there is a need to cover to a greater or lesser extent the disc which is being supplied.

The deflector is preferably adjustable continuously in accordance with the work requirements. However, there is provision for it to be able to be adjustable via discrete positions which are predetermined. With reference to the embodiment of Figure 6, in order to promote the adjustment, there is positioned closely behind the channels 24 a graduated scale 46 which, as a result of the effect of an indicator 47, displays the throttling of the launch sector S imposed.

The fixed set of blades 36 is made necessary by the dimensions because there is physically not enough space to construct the deflector provided only with sets of movable blades. For this reason, a selection has been made for combining fixed sets of blades and movable sets of blades although the use of one set of blades which is exclusively movable has not been excluded.

The adjustment of the sets of movable blades 33 takes into account the "ballistic" properties of the material distributed, such as the specific mass, the shape of the granules, the tendency to drift and the circumstances in which it is distributed, for example, the presence of wind, atmospheric events, etc.