WO2022112256A1

WO2022112256A1 - Cutting tool and portable agricultural machine comprising said cutting tool

Info

Publication number: WO2022112256A1
Application number: PCT/EP2021/082697
Authority: WO
Inventors: Roberto Caraceni; Stefano FIORANI
Original assignee: Rost Srl
Priority date: 2020-11-25
Filing date: 2021-11-23
Publication date: 2022-06-02

Abstract

A cutting tool (100) comprising: a central hub (1) with an axis of rotation (X); a plurality of blades (3, 4) disposed around the central hub (1) in equidistant position from the central hub (1); wherein said plurality of blades (3, 4) comprises removal blades (3) and penetrating blades (4) disposed in alternate position and equally spaced from each other angularly; and a frame (2) that is integral with the central hub (1) and connects the blades (3, 4) to the central hub (1); the peculiarities of the cutting tool (100) are that: each blade (3, 4) consists in a plate comprising sharp edges (31, 41, 10 32, 42); a beveled/rounded corner (S1) is provided between two adjacent sharp edges (31, 32) of the removal blade (3); and a sharp corner (S2) is provided between two adjacent sharp edges (41, 42) of the penetrating blade (4) in adjacent position.

Description

DESCRIPTION

CUTTING TOOL AND PORTABLE AGRICULTURAL MACHINE COMPRISING SAID CUTTING TOOL

The present patent application for industrial invention relates to a cutting tool and to a portable agricultural machine comprising said cutting tool.

The sector of reference is the one of agricultural machines used for tilling or for breaking up the clods of earth in order to prepare the seedbed for 5 sowing.

Powered cultivators are known on the market, which are used for breaking up the soil or for creating small furrows in the ground.

The powered cultivators of the prior art consist in a machine provided with a supporting frame equipped with wheels for movement, with a handlebar 10 for holding and guiding the machine and with a motor.

Tools that rotate around a horizontal axis perpendicular to the traveling direction of the powered cultivator are mounted on the supporting frame. More precisely, said rotary tools are mounted on a horizontal shaft operated by said motor. Each tool comprises identical blades that project radially from the 15 horizontal shaft and penetrate the ground during the rotation of the horizontal shaft.

Said blades usually have a warped shape.

Similar powered cultivators are operated by a user who pushes them from behind and guides them while holding his hands on the handlebar.

20 These powered cultivators are impaired by drawbacks and limitations.

A first limitation concerns the fact that such tools do not allow to effectively break up clods of soil.

In addition, because of their shape, the blades of the tools are subject to a high friction against the ground, resulting in a high wear of the blades and in a 25 high stress of the motor that operate the shaft from which the blades radially project.

In particular, if the ground is particularly dry and hard, during the impact of the blades on the ground, stresses and bending forces are generated on the blades which tend to ruin and wear the blades over time, consequently requiring the replacement of the tool itself. Moreover, the resisting force against blades is discharged directly on the motor that operates the horizontal shaft, causing failures, or even in the worst case, the breakage of the motor. As a result, it will be necessary to replace the motor. It is easy to understand how such powered 5 cultivators are extremely unreliable and expensive.

A further limitation that impairs the powered cultivators of the prior art concerns the fact that their maneuverability is compromised and limited. In particular, it is extremely complicated to follow a curved trajectory in order to get around fixed obstacles, such as trees, poles and the like. In view of the above, it 10 is not possible to work the soil in a homogeneous way.

US6364030B1 describes a blade assembly for installation on a shaft of a light duty agricultural equipment for tilling the soil (such as a power tiller, powered cultivators, or the like). The blade assembly comprises a first blade disc and a second blade disc coaxially mounted to the first blade disc. Each 15 blade disc comprises an annular portion suitable for being mounted on the shaft of the agricultural equipment and a set of teeth that extend radially from the annular portion. The teeth of each blade assembly are of two types and are alternated with each other. Specifically, the teeth comprise:

- first teeth comprising a laterally folded end portion;

20 - second teeth comprising a front edge having a concave or convex curvilinear portion.

Said blade assemblies work the ground in two different ways during the rotation of the shaft of the agricultural equipment thanks to the provision of different types of teeth. However, said blade assembly is not efficient because 25 the teeth can only break up the soil by penetrating and cutting the ground without moving or turning the ground over.

CN106612643A describes an implement for agricultural equipment comprising an annular plate suitable for being mounted on a shaft of the agricultural equipment and knives or machetes that extend radially from the 30 annular plate. Said knives or machetes are of two types so as to impact differently on the ground. Also in this case, the tool is inefficient and unable to work the soil properly because the knives or machetes penetrate and cut into the soil without moving and turning the soil over.

GB312800A describes a tool for agricultural equipment comprising a 35 central hub suitable for being mounted on a shaft of the agricultural equipment from which digging teeth and cutting blades extend radially. Such a tool allows only for digging and cutting the soil without moving or turning the soil over.

The purpose of the present invention is to overcome the drawbacks of the prior art by devising a cutting tool for an agricultural machine, capable of 5 effectively breaking up the clods of earth with minimum wear.

A further scope of the present invention is to devise a cutting tool such that the agricultural machine provided with it has a lower energy consumption than the powered cultivators or rotary tillers of the prior art.

A further scope of the present invention is to devise an agricultural 10 machine comprising said tool, which is extremely easy to move so as to reach any point of the ground, bypassing any obstacle.

These purposes are achieved according to the invention with the features listed in the appended independent claim 1 .

Advantageous embodiments appear from the dependent claims.

15 The cutting tool according to the invention is defined by claim 1.

For the sake of clarity, the description of the cutting tool according to the invention is continued with reference to the appended drawings, having only an illustrative and non-limiting value, wherein:

Fig. 1 is an axonometric view of the cutting tool according to the 20 invention;

Fig. 2 is a front view of the cutting tool of Fig. 1 ;

Figs. 3 and 4 are views of the removal blade and of the penetrating blade of the cutting tool of Fig. 1 ;

Fig. 5 is a schematic axonometric view of an agricultural machine 25 according to the invention comprising the cutting tool of Fig. 1 ;

Fig. 6 is an axonometric view of the cutting tool and of the second end of the supporting rod, detached from each other, in such a way as to show the weed cutting assembly.

With reference to Figs. 1 and 2, a cutting tool according to the invention 30 is described, which is collectively indicated with reference numeral (100).

The cutting tool (100) comprises:

- a central hub (1) having an axis of rotation (X);

- a plurality of blades (3, 4) arranged perimetrically about the central hub (1) and all equidistant from the central hub (1); - a frame (2) which is integral with the central hub (1) and connects said central hub (1) to said plurality of blades (3, 4).

The number of blades (3, 4) is preferably comprised between eight and sixteen.

5 The plurality of blades (3, 4) comprises removal blades (3) and penetrating blades (4). The removal blades (3) and the penetrating blades (4) are alternated and equally spaced around the frame (2) angularly.

Each blade (3, 4) consists of a plate and comprises a longitudinal axis (Y3, Y4) and sharp edges (31 , 41 32, 42)

10 The frame (2) consists in a star-shaped frame including a plurality of supporting arms (20), one for each blade (3, 4), which project radially from the central hub (1) and each one being provided with a longitudinal axis (V). Each supporting arm (20) comprises a first end (2a) connected to the central hub (1) and a second end (2b) whereon one of said blades (3, 4) is disposed.

15 Preferably, said first end (2a) is welded to the central hub (1) whereas the second end (2b) is butt welded to said blade (3, 4). More precisely, each blade (3, 4) lies on a plane orthogonal to the longitudinal axis (V) of the supporting arm (20) to which it is connected.

With reference to Figs. 2, 3 and 4, the differences between the removal 20 blades (3) and the penetrating blades (4) can be visually appreciated.

In particular, each removal blade (3), which is shown in detail in Fig. 3, has a rounded/beveled corner (S1 ) between two adjacent sharp edges (31 , 32).

Instead, each penetrating blade (4), which is shown in detail in Fig. 4, has a sharp corner (S2) between two adjacent sharp edges (41 , 42).

25 In particular, the plate of the blade (3, 4) has a rectangular shape and comprises two longitudinal sharp edges (31 , 41) and two transverse sharp edges (32. 42).

With reference to the removal blade (3), said beveled/rounded corner (S1) is disposed between two adjacent sharp edges (31 , 32), with a radius of 30 curvature greater than 15 mm.

With reference to the penetrating blade (4), said sharp corner (S2) at 90° is disposed between two adjacent sharp edges (41 , 42).

Each blade (3, 4) is mounted on the supporting arm (20) centrally and comprises a portion that protrudes from one side of the supporting arm (20) and 35 the other portion that protrudes from the other side of the supporting arm (20). Preferably, as shown in Fig. 2, the longitudinal axis (Y3, Y4) of each blade (3, 4) is:

- incident with respect to a plane orthogonal (O-O) to the axis of rotation (X) of the central hub (1); and

5 - oblique with respect to the axis of rotation (X) of the central hub (1).

Always with reference to Fig. 2, advantageously, the longitudinal axis (Y3, Y4) of each blade (3, 4) is inclined at an angle (a) with respect to the plane orthogonal (0-0) to the axis of rotation (X) by a value between 5° and 10°.

When it impacts and penetrates into the ground, the penetrating blade 10 (4) cuts and breaks up the soil, whereas the removal blade (3) acts as a shovel that collects and carries away the earth crushed by the previous penetrating blade (4).

So, first the penetrating blade (4) penetrates and breaks up the clods and the soil, and immediately after the removal blade (3) removes the soil in 15 order to leave new free ground for the next penetrating blade (4) that is about to impact on the ground. Therefore, by removing the soil, the removal blade moves and turns the soil that has been broken up previously.

Such a continuous penetration and removal action of the soil makes it possible to work and turn over the soil more efficiently and better than in the 20 prior art with tools provided with blades that are all identical, or with knives that cut the soil along a direction orthogonal to the axis of rotation of the hub.

Advantageously, holes or openings (F) are provided on the blades (3, 4) in order to discharge the soil and the material during the impact of the blades (3, 4) on the soil.

25 With reference to Fig. 5, a further object of the present invention is a manual agricultural machine (MA) comprising:

- an agricultural tool (100) as described above;

- a supporting rod (5) comprising a first end (5a) including a handle section (50a) suitable for being held by a user, and a second end (5b) on which

30 the cutting tool (100) is mounted in projecting position;

- driving means, not shown in the appended figures, for driving the cutting tool (100) about the axis of rotation (X) of the central hub (1).

The supporting rod (5) has a longitudinal axis (Y) and comprises handles (N) on the handle section (50a) that are suitable for being held by a user to 35 support and operate the agricultural machine (MA) manually. The cutting tool (100) is mounted with its axis of rotation (X) perpendicular to the longitudinal axis of the supporting rod (5).

Said driving means comprise:

- a shaft (A), disposed on the second end (5b) of the supporting rod (5);

5 said shaft (A) protrudes laterally and perpendicularly with respect to the longitudinal axis (Y) of the supporting rod (5) and is solidly connected to the central hub (1);

- operating means for moving the shaft (A).

The driving means comprise an actuator, preferably an electric motor, 10 powered by a battery, arranged in the proximity of the handles (N) in order to be operated by the user, and a transmission that connects the actuator to the shaft of the driving means to rotate the shaft (A) and operate the cutting tool.

Transmissions and/or reduction gears can be positioned between said motor and said shaft (A) to transmit the motion from the motor to the shaft (A).

15 Advantageously, the supporting rod (5) comprises a protective wing (AP) that protrudes externally from the supporting rod (5) and acts as a shield for the user by intercepting dirt, stones, grass, and the like that are forcefully discharged by the cutting tool (100) when the soil is worked.

The actuating means can be operated manually by the user by means of 20 buttons and levers disposed on the handle section (50a) and operatively connected to the actuator (motor).

Preferably, said driving means are configured in such a way that said cutting tool (100) can be moved in two different directions of rotation, i.e. clockwise and counterclockwise.

25 Moreover, said driving means are configured in such a way that said cutting tool (100) can be rotated at an angular speed comprised between 360 s and 18007s, namely one revolution per second and five revolutions per second.

With reference to Fig. 6, advantageously, said agricultural machine (MA) comprises a cutting assembly (G) comprising at least two blades (81 , 82) 30 cooperating with each other, of which:

- at least one fixed cutting blade (81) that is disposed on the second end (5b) of the supporting rod (5) and extends toward the cutting tool (100), and

- at least one movable cutting blade (82) that is disposed on the frame (2) of the cutting tool (100) and extends towards the second end (5b) of the

35 supporting rod (5). In particular, in the preferred embodiment of the invention, said cutting assembly (G) comprises two fixed cutting blades (81) and two movable cutting blades (82).

Each fixed cutting blade (81) is spaced apart by a distance (d1) from the 5 axis of rotation (X) of the central hub (1), i.e. by a distance (d1) from the axis of the shaft (A).

The movable cutting blades (82) are spaced apart by a distance (d2) from the axis of rotation (X) of the central hub (1).

Preferably, the difference between the distance (d1) and the distance 10 (d2) has a modulus value of less than 0.2 cm.

In this way, during the rotation of the cutting tool (100), the movable cutting blades (82) pass in the vicinity of the fixed cutting blades (81), cutting any weeds or the like that are wound and tangled around the shaft (A) to which said central hub (1) is integrally connected. More precisely, when the movable 15 cutting blade (82) passes in proximity of the fixed cutting blade (81), it essentially performs a scissor-like action by cutting the weeds and the like that are entangled around the central hub (1).

It should be noted that, for the purpose of achieving the objectives pursued by the invention, it is irrelevant whether the movable cutting blades (82) 20 have a higher or lower distance (d2) than the distance (d1) of the fixed cutting blades (81).

Otherwise said, during the movement of the cutting tool, the movable cutting blades (82) can define a circular trajectory that contains the two fixed cutting blades (81) and a circular trajectory that is contained between the two 25 fixed cutting blades (81).

Again with reference to Fig. 6, the fixed cutting blades (81) are obtained on a plate (P) provided with a central hole crossed by the shaft (A) to which the central hub (1) is connected. Said plate (P) acts as a shelter to protect the various mechanical parts from the weeds, the mud and other elements that get 30 tangled around the shaft (A), between the cutting tool (100) and the second end of the supporting rod.

For working the soil and breaking up the clods of earth, it is therefore necessary to operate the actuator of the driving means in order to drive the cutting tool (100) in rotation. The user can move the supporting rod (5) as desired in order to tilt the central hub (1) and thus modify the inclination of the blades (3, 4) on the ground.

As mentioned above, after starting the rotation of the cutting tool (100), 5 the penetrating blades (4) and the removal blades (3) blades act on the ground, penetrating and removing the soil continuously.

The applicant discovered that the alternation of the penetrating action and of the removing action given by the blades (3, 4) increases the efficiency of the cutting tool (100) and of the agricultural machine (100) as a whole 10 compared to the machines of the prior art (powered cultivators and power tillers), since it allows for breaking up the soil in a better way compared to the machines of the prior art, also consuming less energy than the machines of the prior art provided with the conventional tools of the prior art.

In particular, the applicant performed experimental tests, comparing the 15 output of the agricultural machine provided with the cutting tool (100) according to the invention with a machine of the prior art provided with tools with identical blades.

From the experimental tests, the applicant discovered that when using the agricultural machine provided with the cutting tool (100) according to the 20 invention, the power consumption values are reduced by approximately 20 - 25 % compared to those of the machines of the prior art.

These power absorption values were obtained and validated through tests performed out on different types of soil.

Furthermore, it was shown that the configuration of the tool according to 25 the invention, wherein the blades (3, 4) are mounted on the supporting arms (20) of the frame (2) significantly reduces the resistance exerted on the blades (3, 4) by the ground and therefore reduces the stress on each blade (3, 4) and consequently the wear of the blades (3, 4) and the failures of the actuator.

Finally, it is important to point out that, since the supporting rod (5) of the 30 cutting machine is supported and is moved manually by the user, the cutting tool (100) can be more or less inclined easily, reaching any point on the ground and bypassing any fixed obstacle, such as bushes, trees or poles.

Numerous variations and detailed modifications may be made to the present embodiment of the invention, which are within the scope of a person skilled in the art, still falling within the scope of the invention as expressed by the appended claims.

Claims

1) Cutting tool (100) comprising: a central hub (1 ) with an axis of rotation (X); a plurality of blades (3, 4) disposed around the central hub (1) in equidistant position from the central hub (1); wherein said plurality of blades (3, 5 4) comprises removal blades (3) and penetrating blades (4) disposed in alternated position and equally spaced angularly; and

- a frame (2) that is integral with the central hub (1) and connects the blades (3, 4) to the central hub (1); characterized in that:

10 each blade (3, 4) consists in a plate comprising sharp edges (31 , 41 , 32,

42); wherein a beveled/rounded corner (S1) is provided between two adjacent sharp edges (31 , 32) of the removal blade (3); and wherein a sharp corner (S2) is provided between two adjacent sharp 15 edges (41 42) of the penetrating blade (4).

2) The cutting tool (100) of claim 1 , wherein said plate of the blade (3, 4) has a rectangular shape and comprises two longitudinal sharp edges (31 , 41) and two transverse sharp edges (32, 42).

3) The cutting tool (100) of claim 1 or 2, wherein said frame (2) 20 comprises a plurality of supporting arms (20), one for each blade (3, 4); each supporting arm (20) protrudes radially from said central hub (1) and comprises a first end (2a) connected to the central hub (1), and a second end (2b) provided with one of said blades (3, 4).

4) The cutting tool (100) of claim 3, wherein each blade (3, 4) lies 25 on a plane orthogonal to a longitudinal axis (V) of the supporting arm (20).

5) The cutting tool (100) of any one of the preceding claims, wherein the beveled/rounded corner (S1) between two sharp edges (31 , 32) of the removal blade (3) has a radius of curvature higher than 15 mm.

6) The cutting tool (100) according to any one of the preceding 30 claims, wherein the sharp corner (S1) between two sharp edges (41 , 42) of the penetrating blade (4) is a 90° corner.

7) The cutting tool (100) of any one of the preceding claims, wherein each blade (3, 4) has a longitudinal axis (Y3, Y4) that is: - incident with respect to a plane (O-O) orthogonal to the axis of rotation (X) of the central hub (1); and

- oblique with respect to the axis of rotation (X) of the central hub (1).

8) Agricultural machinery (MA) comprising:

5 - a cutting tool (100) according to any one of the preceding claims; a supporting rod (5) comprising a first end (5a) provided with a handgrip section (50a) suitable for being held by a user, and a second end (5b) where said cutting tool is mounted in projecting position; driving means for driving the central hub (1) of the cutting tool 10 around its axis of rotation (X); said driving means comprising a shaft (A) disposed on the second end (5b) of the supporting rod (5) that projects laterally from the supporting rod (5) and is integrally fixed to the central hub (1); operating means for operating the shaft (A).

9) The agricultural machinery (MA) of claim 8, comprising a cutting 15 assembly comprising at least two cooperating blades, namely at least one fixed cutting blade (81) disposed on the second end (5b) of the supporting rod (5) that extends towards the cutting tool (100), and at least one mobile cutting blade (82) disposed on the frame (2) of the cutting tool (100) that extends towards the second end (5b) of the supporting rod (5); said at least one mobile 20 cutting blade (82) passing in the vicinity of said at least one fixed cutting blade (81) during the rotation of the cutting tool (100), in such a way to cut the weeds entangled around the shaft (A).

10) The agricultural machinery (MA) of claim 9, wherein said at least one fixed cutting blade (81) has a distance (d1) from the axis of rotation (X) of

25 the central hub (1); wherein said at least one mobile cutting blade (82) has a distance (d2) from the axis of rotation (X) of the central hub (1); wherein the difference between the distance (d1) and the distance (d2) has a value in modulus lower than 0.2 cm.