DESCRIPTION

The present invention refers to an improved apparatus for the separation of agricultural or vegetable products that are joined to each other through relative connecting appendages, such as petioles, stems, stalks, etc., as for example cherries, small clusters of cherry tomatoes, etc., that have been previously picked and that normally arrive joined in small bunches or that are still connected to each other through the relative stems, in particular in the case of cherries.

It is well known that such vegetable products are cultivated on an industrial scale to be marketed through the networks of the large-scale retail trade. In order to be prepared for such use, said products must normally go through suitable treatment and processes, such as washing, separation from each other when they occur in bunches, clusters, etc., weighing, sizing, sorting on the basis of predefined characteristics such as colour, degree of ripeness, etc.

In general, these sorting operations are widely known and easily carried out without particular problems when the vegetable products reach the sorting systems and are loaded on it piece by piece, as is the case with apples, pears, melons, etc.

On the other hand, if these products are still bunched together, one of the first operations to be carried out on them is naturally to separate them.

Thus, when it is necessary to process agricultural products that are intrinsically joined in bunches or clusters, such as for example cherries, green beans, etc., it is evident that to singularize the produce (it is assumed that this term is well known to a reader who is an expert in the field), it is essential to eliminate any vegetable elements, such as stems, stalks, and petioles that originally keep said vegetable products bunched together.

For this purpose, there are various widely known processes and systems used to separate said groups of products into single products, that is, separated from each other.

Hereafter will be considered those systems that are used to separate said clusters exclusively by cutting said stems, stalks, etc., with rotating blades.

Later in the present description, specific reference will be made to cherries, but it is implicit that what is illustrated applies without any reserve or limitation to any other type of product having similar characteristics of occurring in bunches, clusters, etc.

Various known documents and patents illustrate different processes and means suitable to performs said operation of cutting the stems, such as for example:

US 5,050,492; US 3,1 15,169; FR 2 672 776; ES 2241 465; FR 2 892 053.

The majority of such patents perform the cut by carrying the clusters to be processed/cut by means of moving belts, on which the clusters are often piled up in disorderly heaps.

The solution with moving belts, although simple to apply, does not however ensure that the cutting of the stems will be carried out in a regular manner, and particularly at a point removed from the knot joining the stems; this also occurs if the stems in the clusters are overlapped on the belts, due to the fact of being loaded on the belts in a haphazard and unguided manner.

This causes a serious problem in the field: in fact, it is widely observed that, in order to ensure a more pleasing and attractive presentation for the average consumer, it is essential that the stems of such products, for example cherries, be cut at a point nearest to the point or node connecting the stems, so as to avoid the very undesirable effect that some stems are too short, while other stems remain needlessly connected through a V-shaped connecting point.

Practically, this happens if the transportation and cutting means neglect the essential fact that the length of the stems can vary, even considerably, from one lot of product to another.

Moreover, the use of the same system, be it of belt type or flat conveyor type, to carry clusters of different characteristics to the cutting area, almost always generates the problem described above.

US Patent 7,033,631 B1 discloses an apparatus suitable to carry the clusters to be separated to a cutting area having a plurality of rotating blades, where the individual clusters are sent on a plurality of upward sloping ramps of triangular cross section, so that the clusters overlap each other in a suitable manner in which the part of the stem that arrives at the point of intersection with the blade is naturally the closest part to the point that joins the stems.

Moreover, the height of said ramps can be adjusted to suit the average length of the stems of the lot of product to be separated.

However, this solution presents some serious drawbacks; in fact the movement of the clusters toward the rotating blades is obtained by means of a continuous shaking on the inclined support plane on which the clusters to be cut are placed, and this shaking is harmful for the products, especially in the case of delicate produce, due to their rubbing against the plane itself.

The continuous shaking of the inclined support plane also requires a suitable mechanism with a motor to which are connected cam elements, and, as is well known, the production of an alternative movement of a rigid structure with respect to another rigid structure entails a greater complexity of construction of all the drive and control devices.

Finally, as can be appreciated from Fig. 9 of the above-mentioned US 7,033,631 B1 patent, the inclination of the ramp 46 is substantially constant, apart from the end section 48, which has an inclination slightly different from the inclination of the initial section; and these inclinations of said ramp 46 are invariable, that is, they cannot be modified to suit the length of the stem; this causes an inefficient adjustment of the cutting operation because, as is shown in said Fig. 9, with short stems the cherries can reach a position on the ramp 46 such as to become detached from the vibrating plane 38, and thus their movement toward the rotating blades will obviously be hindered, or even prevented.

It would therefore be desirable, and is the main objective of the present invention, to realize a type of automatic system for cutting the stems of the clusters of vegetable products that makes it possible to cut said stems in the area of the point of connection, without encountering the problems described above.

This objective is achieved through an apparatus built and operating in accordance with the accompanying claims.

Characteristics and advantages of the invention will be evident from the following description, given by way of example and without limitations, with reference to the enclosed drawings, wherein:

• figure 1 illustrates an external perspective view from a diagonal position of an apparatus according to the invention.

• figures 2, 3 and 4 illustrate respective schematic and enlarged views, similar to fig. 1 , of respective operating arrangements of an individual cutting module of an apparatus according to the invention; • figures 2A, 3A and 4A illustrate respective views in lateral plane projection of a portion of an apparatus according to the invention, corresponding respectively to the arrangements of figures 2, 3 and 4;

• fig. 5 illustrates a simplified perspective view from above of a portion of the apparatus shown in fig. 1 , seen from a point ahead of the axis of rotation of the rotating blades;

• fig. 6 illustrates a view similar to fig. 5, but with a single enlarged portion and from a viewpoint nearer to the axis of rotation of the rotating blades;

• fig. 7 illustrates a view of the portion of fig. 5, seen in a diagonal perspective from above but from a viewpoint behind the axis of rotation of the rotating blades;

• fig. 7A shows an enlargement of a lateral part of the portion of the apparatus of fig. 7;

• fig. 8 illustrates a plane view from above of the portion of the apparatus of figures 5-7A;

• fig. 9 illustrates a front plane view of the apparatus of figures 5-7A;

• fig. 10 illustrates an aligned lateral plane view of a detail of the apparatus of the above figures 5-7A;

• fig. 1 1 illustrates a basic schematic diagram of a manner of operation of the invention;

• fig. 12 illustrates a simplified geometrical schematic diagram of the basic manner of operation of the invention, as seen in a lateral flat projection.

* * * *

With reference to the figures, an apparatus for cutting the stems of clusters of vegetable products, in particular cherries, comprises in general:

- a support structure with a frame with two parallel horizontal side members 1 A, 1 B defining between them a substantially flat surface "S", typically rectangular; said surface "S" is a purely geometrical definition, and does not identify any material means, as will become clear in the description;

- a plurality of cutting modules 2A, 2B, 2C, 2D, 2E, that are substantially identical to each other and each provided with a common rotating shaft 32A, 32B, 32C, 32D, 32E, ... ; said rotating shafts being parallel to each other and arranged above said surface "S", and therefore are in succession, so as to be able to intercept practically all of the clusters of products carried by the underlying table.

Said cutting modules are identical and therefore, for the sake of simplicity, only one of them will be described hereafter, for example module 2C (see fig. 2), it being understood that the relative explanation extends to all the other modules.

In general, the description and the claims will refer sometime to a single element, and sometime to a number of similar elements; since said cutting modules are substantially similar, and since each cutting module includes a plurality of rotating blades and relative associated elements, in particular the relative ramps and the means suitable to modify their position, that are similar or identical, it remains likewise understood that the reference to a single one of such modules, or to a single one of said means or blades extends successively and obviously to all the other modules and other means or blades, as is shown clearly in the enclosed figures.

Said rotating shafts are arranged above the conveying means that cover said surface "S", which conveying means are suitable to carry the produce placed on them toward said rotating blades.

Said module 2C is equipped with:

- a plurality of rotating blades 1 1 , 12, 13, 14, arranged in fixed positions along its length;

- a plurality of positioning ramps 1 1 -1 , 12-1 , 13-1 , 14-1 , in which each of said ramps is arranged in a position corresponding to a respective rotating blade;

- said ramps having an elongate shape in the direction of movement of said conveying means and noticeably flattened and oriented vertically;

- the respective upper edge of which is oriented downward toward said conveying means, with an inclination such that the height of said edges increases in the direction of the respective blade, arranged above said conveying means;

- so that the clusters of produce placed on said conveying means are carried toward said ramps whose upper edge set at an acute angle, respectively 1 1 -2. 12-2, 13-2, ... (fig. 10), determines the point of intersection of the stems of each cluster that is intercepted by the relative blade.

To be precise, each ramp is aligned with the respective blade, and is arranged in its lower area; in order to allow the ramp to carry the clusters of produce toward the respective blade, said ramp is provided in its upper part with a respective recess 1 1 -3, 12-3, 13-3, 14-3 of a size suitable to accommodate the relative blade 1 1 , 12, 13, 14, .... In this manner, the clusters of vegetable products are carried toward said ramps, each of which intercepts a single cluster at a time and lifts the relative stem, which straddles the ramp, and thus, continuing on its movement, is intercepted by the relative blade and cut at the corresponding point on the respective edge.

Also, as essential element for the functioning of the invention, the transportation and movement of said conveying means is attained as follows:

With reference to figure 9, said conveying means include a table formed by a plurality of parallel grooves 20, 21 , 22, 23, 24, 25, ... arranged horizontally and substantially orthogonal to said rotating shafts.

Said grooves are reciprocally separated by respective raised portions 20-A, 21 - A, 22-A, the set of said grooves and relative raised portions is typically formed by a continually moving conveying belt.

This moves in a direction parallel to said grooves 20, 21 , 22, 23, 24, 25 and relative raised portions, and thus moves orthogonally to said rotating shafts.

In addition, each ramp is superimposed on a respective groove and is inclined and aligned with respect to the latter, so that the projection of each of said ramps with respect to the relative groove is aligned with the same groove; in particular, the position of the tip 1 1 -P, 12-P, 13-P, 14-P, ... (see fig. 2) of said ramps is set at an optimal height H1 from the top surface of the respective groove, as shown in fig. 10.

Since, in fact, most of the vegetable products, in particular cherries, that are joined in one cluster, come to be inside the same groove, it is evident that the operation of cutting the stems is more effective and productive if the cutting blades, and therefore the relative ramps, are centred and aligned within respective ones of said grooves.

In fact, the task of performing the cutting of substantially all the stems relies on the fact of having not only one cutting module, but a plurality of cutting modules 2A, 2B, 2C arranged in succession, one downstream of the next, with respect to the direction of movement of the table formed by said grooves alternated with respective raised portions.

The operation of the apparatus described here is as follows: the various clusters are set down and distributed with known means and manners on said table formed by the various grooves 20, 21 , 22, 23, 24, 25, ... and the relative raised portions 20-A, 20-B, 20-C, 20-D, ....

With the movement of said conveyor toward said ramps and rotating blades, the products reach the position of said ramps, and due to the dragging movement to which said stems are subjected they are intercepted by respective ramps and are thus naturally captured and lifted, by effect of the dragging movement, up to where they reach the relative rotating blade, which cuts them exactly at the upper edge of the relative ramp.

Thus is achieved a first objective of the invention, which consists of carrying the various clusters to the cutting station without subjecting them to vibrations, shaking, etc., which would naturally damage them.

However, as already mentioned, the situation described above yields optimum results only if the distance of the upper edge of the ramp from the bottom of the adjacent groove is substantially similar to the height of the stem or, more precisely, to a length of the stem such that, considering also the size of the fruit, the knot of the stem positions itself exactly, or almost exactly, at the height of the upper edge of the ramp.

In fact, if this condition does not occur, and if for example the stem is longer, it may happen that the ramp could fail to catch and lift the knot, because the knot positions itself naturally on the ramp itself; in this situation, the blade reaches the stem, and then cuts it in a position far from the knot, which would be decidedly unhelpful and undesirable.

Another serious shortcoming found in similar machines already present and operating on the market, consists of the fact that, although they are built with a plurality of cutting modules, each of which is fairly similar in principle to the cutting modules 2A, 2B, 2C, 2D, 2E, ... of the present invention, these machines require however that, when it is necessary to modify the height or the inclination of the ramps, it is also necessary to operate:

- not only one by one the mechanisms/devices that regulate the height of each of said cutting modules, that is, the height of the respective rotation shaft on said table,

- but also to adjust the devices that modify the inclination of the ramps relative to each rotating shaft of the respective cutting module.

This operation, although straightforward and easy, is still extremely time- consuming from the productive point of view, as it requires interrupting the processing of the products and intervening manually and sequentially on each cutting module.

From the economical point of view, this situation is unacceptable both because it forces a machine shut-down that can sum up to a few hours, which is intolerable when it is necessary to process fresh, delicate and prized produce in very short times, and because of the burden of the maintenance and operating times that must be expended to adjust, one by one, the position of the individual cutting modules.

To overcome these serious disadvantages, the improvements hereunder teach the implementation of such means as make it possible to adjust as desired the height of the ramp over the underlying table (grooves and raised portions), and at the same time to also adjust the height of the relative rotating shaft, so that the relationship between the shaft, and therefore the relative rotating blades, and the relative ramps, is substantially constant or almost so, with such a procedure and means as make it possible to adjust the height of all the cutting modules automatically and all at the same time, in a single operation, so that all the cutting modules are adjusted to a new operating condition.

It is clearly evident that such means and the relative operating procedure allows a dramatic reduction of the times that were previously required to adjust the machine; this is so evident that it will not be specified further.

For the purpose hereof, and referring to the figures, a mobile structure is provided:

- formed substantially with a geometry similar to the geometry of said support structure 1 A, 1 B, and comprising two parallel horizontal side members 5-A, 5-B (see figures 1 , 2 and 3),

- overlying said support structure;

- said mobile structure being connected to said fixed structure through a plurality of movable arms, ideally only four arms 6, 7, 8, 9 (fig. 1 );

- each of which is connected (fig. 2A) with one of its ends 6A to a position in said side member 1 A, and with the respective other end 6B to a respective position of the side member 5-A belonging to said mobile structure, wherein said ends 6A, 6B relative to a specific arm 6 are arranged on different vertical straight lines r, t.

Thus, if such configuration is replicated, with identical measurements, for both side members of both said mobile structure and said fixed structure, the configuration illustrated in fig. 1 is obtained.

In practice, each lower side member of the fixed structure is connected to the overlying side member of the mobile structure through two similar pairs of separate arms 7 and 8, 9.

Thus a construction of a "parallelogram" type is provided, so that said mobile structure becomes suitable to move with respect to said fixed structure by means of a movement that will be defined hereunder as "translational motion following a rotating path".

In fact, the mobile structure rotates effectively around predefined points of the fixed structure, due to its being pivoted on said arms 6, 7, 8 and 9, but also due to the "rhombus" shaped structure that is formed:

- by to two arms 6, 7 placed substantially on the same vertical plane between a pair of fixed and mobile side members 1 A and 5-A;

- and by to the portions of the same side members included:

- between the pivot points 6A, 7A located on the side member 1 A, and similarly between the pivot points 6B, 7B (these are shown in fig. 1 1 ) relative to the side member 5-A.

However, figure 1 1 clearly illustrates the geometrical situation described above, referred to only the side members 1 A and 5-A.

If the upper structure comprising the side members 5-A and 5-B is lifted (through known means that are not included in the invention), then, as shown schematically in fig. 1 1 , said same upper side members 5A and 5B are displaced with a translational motion, because they are always parallel to each other, but also with a rotatory motion, because the mobile arms remain hinged on the respective pivot points on the fixed lower structure.

We have thus explained the meaning of the "translational motion following a rotatory path" defined above.

Besides, this is the typical movement of any structure in the shape of a parallelogram.

In short, given the configuration illustrated herein, it becomes possible to lift the mobile structure, with respect to the fixed structure, and in particular the side members 5-A, 5-B with a translational motion following a rotatory path.

Moreover, said ramps are connected to the two upper side members 5-A and 5- B of the upper mobile structure, so that its lifting also automatically generates the partial lifting of the relative ramps, however without having the position of the respective points increasing or decreasing its vertical distance from the underlying groove, although it may happen that the horizontal position of the same points is modified.

The manner of this connection is explained below.

Naturally, it becomes necessary that the lifting or lowering of the ramps does not cause any problem with the respective blades, which must not be brought to interfere with the ramps themselves, and in any case the reciprocal distance and geometry of the ramp and the respective blade must be respected.

As a result, the axes "X" of the rotating shafts must also be made integral, in the same sense just explained, with said side members.

For this purpose, and with reference to figures 2A, 3A and 4A, said shafts 32A, 32B, 32C, 32D, 32E, ... are mounted on the two upper side members 5-A and 5-B through normal connecting devices, here represented (figures 6, 7, 7A) by two brackets 40, 41 for the shaft 32C.

For what concerns the ramps relative to this cutting module and to said shaft 32C, mechanical connecting means are arranged which comprise, for each cutting module, a connecting pole 50 pivoted, at one end 51 , on a fixed position of said support structure, and in effect to the lower side member 1 A, and with the other end 52 on a first mechanical linking element 53 secured to an auxiliary shaft 55, which is in turn secured to one or more second mechanical linking elements 54 (see in particular figures 7 an 7A) connected to the respective rotating shaft 32-C in a manner that will be explained hereunder.

With particular reference to figures 2B, 2C and 7A, said auxiliary shaft 55 is a non-rotating shaft, arranged parallel to the respective rotating shaft 32C, and engaged at one end 55A with the first mechanical connection 53.

The second mechanical linking element 54 is engaged, at one of its ends 54A, with said shaft 55, and at the other end 54B, with said rotating shaft 32C, in a manner that will be described hereunder.

In addition, on the same auxiliary shaft 55 are fastened integral thereto a plurality of arms 56A, 56B, 56C, 56D, all of which support respective ramps 1 1 -1 , 12-1 , 13-1 , 14-1 , ... at one of their respective lower ends.

It should be immediately made clear that said devices connecting said auxiliary shaft 55 to said mechanical linking elements 53 and 54 and to said arms 56A, 56B, 56C, 56D, ... are such that the shaft 55 is non capable of rotating, about its own axis, with respect to said linking elements and ramps, so that ultimately said types of connecting devices translate into through holes arranged on said linking elements 53 and 54 and arms 56A, 56B, 56C, 56D, which through holes are traversed by said same auxiliary shaft 55, which however is not capable of rotating with respect to them. Finally, the type of connection of said second linking element 54 with said end 54B on the rotating shaft 32C is a rotating connection, naturally in the sense that said shaft 32C traverses in a suitable through hole said end 54B of said second linking element 54, but it can rotate about its own axis, and thus said through hole in said end 54B works as a means that maintains only a definite geometrical position between the linking element 54 itself and the axis of rotation of the shaft 32C, but evidently not between the same linking element 54 and the shaft 32C.

And thus said second linking element 54 is suitable to rotate - only marginally however, as will be explained later - about its respective shaft 32C.

Given the configuration of the elements and devices involved, and comparing together the three figures 2A, 3A and 4A, which show the upper side member 5-A in the two extreme positions of minimum distance and maximum distance, and in an intermediate position, it follows that if the upper side members 5-A and 5-B are lifted, the respective rotating shafts 32-A, 32-B, 32-C are also automatically lifted, and the latter also pull upward the second connecting element 54, which yanks up the respective auxiliary shaft 55, which in turn pulls upward the relative arms 56A, 56B, 56C, which finally also yanks up the relative ramps.

However, due to the fact that said shaft 55 is not free but is connected at its end 55A to the first linking element 53, which is connected to said connecting pole 50, which is in turn connected to the lower side member with the pivot point 51 , it follows that said mechanical linking elements, and therefore said ramp, are not only lifted but also rotated.

Without entering into a rather complex and not essential geometrical discussion, it suffices to note that said ramps, said mechanical linking elements, said mobile arms, their points of application on the respective structures, said jointed arms must be dimensioned, positioned and joined to each other so that the lifting of said mobile structure, exemplified by the upper side members 5-A and 5-B - with respect to said fixed structure - causes the translational-rotatory motion which naturally entrains an equivalent movement in the axes of the respective rotating shafts, because the latter are connected to said upper mobile structure - which includes said side members 5-A and 5-B - by said brackets 40, 41 .

The translational-rotatory motion of said rotating shafts 32-C causes the lifting of the respective second linking elements 54, which drag said auxiliary shaft 55 and also the arms 56-A, 56B, 56-C, so that the tips of the respective ramps - which are connected to said arms - maintain substantially the same height separation H1 on the respective groove, while instead the inclination of said ramps changes with said translational movement following a rotatory path (see fig. 1 1 ).

A person skilled in the field is perfectly capable of imagining and defining the necessary dimensions; only for greater clarity, fig. 12 gives an extremely simplified schematic view of the devices involved, that have been described in the two conditions of minimum and maximum distance between the side members of the two structures, the fixed one and the mobile one.

In said schematic are shown, in particular:

- the upper side member 5-A in the two said positions;

- the axis "X" of the rotating shaft in the two corresponding positions;

- the mechanical connections 53, 54, in the two corresponding positions, in which the position of maximum distance defined above is identified with: 53, 53A and 54, 54A, respectively;

- the connecting pole 50, in the two corresponding positions 50 and 50A;

- and finally the relative ramp, that here for greater convenience will be identified in the two corresponding positions 71 and 72.

Since it is desired that the tip 1 1 -P of the ramp 71 -72 maintain a constant and definite height H1 with respect to the underlying groove, it will be sufficient to dimension the devices involved so as to achieve such condition.

The operation of the improved apparatus described above is as follows: when the height of the ramps is to be changed, the upper mobile structure is lifted from the fixed structure by known means of conventional type.

By the effect of such lifting, said mobile structure is moved upward, but with a movement of "parallelogram" type as explained above.

Said movement of the upper structure also entrains with it, through said brackets 40, 41 , the corresponding rotating shaft 32C, which entrains in turn the mechanical linking elements 54, 53 and the auxiliary shaft 55 interconnected between them.

Since the first linking element 53 is connected, through the pin 52, to the connecting pole 50 which is in turn pivoted at the other end 51 to the lower fixed structure, it follows that the effect of the mechanical connections described, combined with the lifting of the upper structure (side members 5-A and 5-B) causes the lifting of the stem 50. A comparative examination of the positions of the devices described above, as can be seen in the figures 2A, 3A, 4A, where figures 2A and 4A show the two end positions that can be reached by the upper mobile structure, indicates that lifting of the upper mobile structure causes the lifting of the connecting pole 50, and since this is connected to the pin 51 , said lifting of the relative end 52 causes the clockwise rotation of the pole itself 50, and thus, through said connections 53, 54 and the shaft 55, also the rotation of the arm 46-A, 46-B, 46-C, ... and of the respective ramp 1 1 -1 .

However, as the movement of said ramp 1 1 -1 is a complex movement, resulting from the combination of the movement of parallelogram type of the upper mobile structure and of the rotatory movement of the mechanical connections 53, 54, and also of the auxiliary shaft 55 about the shaft 32-C, which is in turn connected to the upper mobile structure, the final effect on the ramp 1 1 -1 is its clockwise rotation which, with a suitable sizing of the devices involved, can generate an increase, with reference to figure 12, of the inclination of the ramp from one position 71 to another position 72.

It will also be evident that figures 3A, 4A, 5A, although they illustrate only the three cutting modules that include the three rotating shafts 32A, 32B and 32C, also apply to all the other cutting modules, not shown in said figures, since all the cutting modules are engaged in a manner identical to those of said upper structure, naturally apart from their position with respect to the latter.

All said devices involved can therefore ensure that, with easy applications of geometrical type, said ramp and therefore in particular its upper edge are inclined so as to be at a greater height, thus making it possible to process clusters having stems of different lengths, without resulting in negative consequences:

- on the reciprocal positioning between the ramp and the relative rotating shaft, and thus the relative rotating blade;

- nor on the height of the tip of the ramp itself on the respective raised portion, on which are straddled the clusters of products that are brought there to be intercepted and lifted and finally cut by the relative blade.

The basic objective of the invention is thus easily and effectively achieved: since all the cutting modules are connected and supported by the two side members 5-A and 5-B it is in fact possible, with the means and manners illustrated above, to adjust in a single and simple operation all the cutting modules, each of them connected with the relative blades and also with the relative ramps. In fact, it will be sufficient to lift or to lower with a single operation the position of the mobile structure, and thus according to the invention also the two side members 5-A and 5-B that are part of it, to achieve the basic objective of the invention of being capable of adjusting, in a single operation, not only the inclination of all the ramps of all the cutting modules supported by said mobile structure, but also all the rotating shafts and the relative blades.

It will be evident to a person skilled in the field that the devices and the lifting/lowering modes and the relative control of said mobile structure are methods completely within the area of expertise of said person, and therefore they will not be specified further.

Finally, with reference to figures 7A and 10, it has been found suitable and advantageous that each of said ramps 1 1 -1 , 12-1 , 13-1 , ... has, on the respective upper edge 1 1 -2, 12-2, 13-2, a respective groove 1 1 -3, 12-3, 13-3, ... suitable to accommodate the lower edge of the respective rotating blade 1 1 , 12, 13, ....

In fact, this characteristic makes it possible that between the blade itself and the respective upper edge of the respective ramp there will be a corresponding acute angle within which is automatically inserted and pushed the stem to be cut, so that said stem cannot escape by slipping off from under the blade, and so that (see fig. 10) the cutting angle "t" between the radius "R" that connects the axis "X" of the rotating shaft and the point of virtual interference "C" between the cutting perimeter of the blade 1 1 and the profile of the respective upper edge 1 1 -2 of the corresponding ramp 1 1 -1 is sufficiently high, and at any rate greater than 90 °.