METHOD AND APPARATUS FOR CUTTING STEMS OR SPEARS OF PLANTS

Abstract: A method for cutting stems or spears of plants, wherein the stems or spears of plants are cut by two sets of blades being moved in relation to each other. The improvement is in that the relative motion of the two sets of blades resulting in cutting the stems or spears of stems is a continuous translatory or rotational motion. An apparatus for cutting stems or spears of plants, wherein two sets of blades being moved in relation to each other are provided. The improvement is in that at least one of the two sets of blades (1, 2; 12, 13) is connected to a drive causing a continuous translatory or rotational relative motion of the two sets of blades (1, 2; 12, 13).

Description: METHOD AND APPARATUS FOR CUTTING STEMS OR SPEARS OF PLANTS Field of the Invention The invention relates to a method for cutting stems or spears of plants, wherein the stems or spears of plants is cut by two sets of blades being moved in relation to each other. The invention also relates to an apparatus for cutting stems or spears of plants, wherein two sets of blades being moved in relation to each other are provided. Background of the Invention For cutting the stems or spears of plants or for iawn-mowing, a lot of cutter machines got previously known. However, all of them realize one of two main principles used fur cutting plants. In the one, the moving blades are pressed against a stationary counter blade, and in the second, the moving blades cut the plant without any counter blade. According to the first principle, the moving blades are driven by an alternating motion and these machines are called alternating cutters whilst, according to the second, by rotational motion and the latter machines are called rotary cutters . The alternating cutters use the principle of shearing between the moving blades and the stationary blades. For this, the stems or spears will be moved and bent sideways and, in de¬ pendency of the speed of the cutter apparatus, forwards and, finally pressed against the stationary blades. Therefore, the average speed of the moving blades must not be smaller thar. 1,2 to 2 times the moving. speed of the apparatus . — __ - As it is clear, the average blade speed can not be increased above a reasonable limit which has its ground in the ever changing speed of the alternating motion and the loads borne in the alternating parts and in their driving elements . Ne- vertheless, this kind of alternating motion exerts a conside¬ rable amount of energy. All these factors result in a maximal working speed of e. g. 8 km/h when the counter blades are stationary and 12 to 14 km/h when the counter blades are also moved in opposite direction to the movement of the first set of blades. In addition, fingers guiding the stems or spears in between the blades can only be used on stationary blades and when both sets of blades are moving they must be aban¬ doned. This further deteriorates the quality of cutting and, at the same time, increases the danger of breakdown or demo- lition of the known apparatusses, not to speak about the more complicated construction and the higher energy consumption. With alternating cutters, also the working width can not be increased beyond a given limit. When the blade beam is too long, it can not follow the unevennesses of the ground and the loads will also be too great. On the other hand, the stems or spears will be cut with rota¬ tional cutters without any counter blades, only by the εtrik- ing impact of the blades rotated with a quite high speed. The blades pivotally jointed on the periphery of a drum or disk are held in direction of the radius by the centrifugal force and they cut the stems or spears when the drum or disk is rotated with high rotational speed not smaller than e. g. 80 m/s. For this, an rpm. of at least 3000 is required. More than one rotor can be used and with this, the working width can be increased. However, the working speed of the apparatus can not greater than e. g. 18 km/h but for this speed, ex¬ tremely great amount of energy is consumed by the apparatus. Essence of the Invention A main object of the invention is to provide a method and an apparatus for cutting stems or spears of plants, with which the quality of cutting as well as the working speed of the cutters can be increased with lower energy consumption as with the conventional apparatusses. A further object of the invention is to provide a simpler construction and more flexible application possibilities than with the conventional apparatusses. According to the improvement of the method in this invention, the relative motion of the two sets of blades resulting in cutting the stems or spears of stems is a continuous transla- tory or rotational motion. In a preferred realization of the invention, the plants being cut are simultaneously gathered. It is also preferable in this invention, when the motion resulting in cutting the stems or spears of stems is produced by individual drives. The drives can be powered by electri¬ city. According to the improvement of the apparatus in this inven¬ tion, at least one of the two sets of blades is connected to a drive causing a continuous translatory or rotational rela¬ tive motion of the two sets of blades. In a preferred embodiment of this invention, one of the two sets of blades is stationarily fixed to a housing of the ap¬ paratus. Therein, fingers can be attached to the blades being stationarily fixed to the housing as extensions of the blades . In another preferred embodiment, the moving blades are fixed on a disk being connected to a rotational drive. In this pre¬ ferred embodiment, the blades being stationarily fixed are arranged in a half—circle facing a direction of movement of the apparatus, and tips of moving and stationary blades are on the same diameter. In another preferred embodiment, the stationary blades have triangular forms, and an acute angle of the triangles are ever increasing when departing from a middle axis of the apparatus. Therein, the stationary blades can be arranged symmetrically to the middle axis of the apparatus. In still another preferred embodiment, the blades being moved are fixed on an endless longitudinal support element guided by at least two pulleys, at least one of which is connected to a rotational drive. It is also a preferred embodiment, wherein the blades being moved are pivotally jointed to each other like members of a chain and said chain is guided by at least two pulleys, at least one of which is connected to a rotational drive. In a further preferred embodiment, the blades have two cutting edges. Therein, the stationary blades can have two parallel cutting edges. In another preferred embodiment, the moving blades and the stationary blades have identical forms. In still another preferred embodiment, more than one cutting units are arranged side by side on a common support of the apparatus. It is also a preferred embodiment, wherein the apparatus or the cutting units have their own energy source and motor device connected to the energy source. Therein, the energy source is at least one accumulator and, preferably, solar cells. Finally, in a preferred embodiment of the invention, the ap- paratus or the cutting units are attached to an outer driving means moving, at the same time, the apparatus, too. Short Description of the Drawings Other objects and details will be described hereinafter with reference to the accompanying drawings. In the drawing, Figs. 1 to 7 show schematic plan views of several preferred embodiments of the apparatus in this invention, Fig. 8 is a cross section according to line VIII-VIII in Fig. 7, Fig. 9» shows a preferred embodiment during operation in plan view, Fig. 10 is a cross section along line X-X in Fig. 9, Fig. 11 illustrates a side elevational view of a further preferred embodiment, and Fig. 12 is a plan view of the embodiment in Fig. 10. Detailed Description of the Preferred Embodiments As it is shown in Fig. 1 , the apparatus has two set of blades for cutting the stems or spears of the plants, namely moving blades 1 and stationary blades 2. From among moving blades 1, only one is shown in Fig. 1, the other are indicated by in- terrupted lines. In this embodiment, the axes of adjacent mo¬ ving blades 1 has 30 to each other. Nevertheless, the number of moving blades 1 can be varied depending on the application purpose of the apparatus. Stationary blades 2 are in this example fixed on a disk 3 being driven rotationally. On the tips of stationary blades 2, fingers 4 are fixed for guiding the stems or spears . Moving blades 1 and stationary blades 2 have two cutting edges 5, 6 and 7, 8. Cutting edges 5 > 6 of moving blades 1 are parallel to each other, whilst cutting edges 7, 8 of stationary blades 2 include an acute angle to each other. Thus, stationary blades 2 have triangular form and are ar¬ ranged symmetric-ally in respect to a middle axis 9. The acute angle between cutting edges 7, 8 are the greater the further stationary blade 2 is away from middle axis 9 - Fingers 4 are arranged as extensions of stationary blades 2 in the direction of moving the apparatus when it f nctions. As it is clear from the drawing, stationary blades 2 are ar¬ ranged in a half-circle facing this direction of movement. Outer edges or tips of moving blades 1 and stationary blades 2 are on the same diameter which, at the same time, deter¬ mines the working width of this preferred embodiment of the apparatus in this invention. In operation, when the apparatus is moved in direction of fingers 4, the stems or spears of the plants to be cut will be divided into bands and guided in between moving blades 1 and stationary blades 2. The width of the so formed bands corresponds to the distance between adjacent fingers 4. Thereafter, when disk 3 is rotated in clockwise direction, the stems or spears will be cut by cutting edge 6 of moving blades 1 and cutting edge 7 of stationary blades 2. The dis¬ tance between adjacent fingers 4 will, at the same time, de¬ termine the measure of bending the stems or spears as well as the length of the stems or spears remaining on the stubble-field after cutting. Therefore, the distance between adjacent fingers 4, the length and the number of moving blades 1 and stationary blades 2 should be determined according to the needs of a given application. As an average, twelve moving blades 1 can be applied as is shown in Fig. 1. For cutting shorter plants, the number of moving blades 1 and stationary blades 2 as well as of fingers 4 should be increas ed . The speed of moving blades 1 should be at least 1 m/s. The direction of rotation can altered when the cutting edge 6 and 7 get edgelesε. Disk 3 will now be rotated in counter¬ clockwise direction and cutting edge 5 and 8 will cooperate. The preferred embodiment in Fig. 2 differs from the previous one in the number and shape of stationary blades 2. As men- tioned above, not only for stationary blades 2 but for moving blades 1, too, the number of them can be increased as neces¬ sitated by the application of the apparatus. Accordingly, an angle 10 of moving blades 1 in respect to each other may vary. In Fig. 3, a preferred embodiment is shown wherein, deter¬ mined by the given task to be solved, only one direction of rotation as shown by an arrow 11 is allowed. This reflects in the shape and non-symmetrical arrangement of stationary blades 2. With this, the optimal shear can be maintained with all cooperating cutting edges 6 and 7 - Two sets of cutting blades are used in the preferred embodi¬ ments as shown in Figs. 4 and 5- In the first one, rotational blades 12 as well as counterblades 13 also rotating but in reverse direction are provided. In this example, blades 12 and counterblades 13 as well as the disks holding them have identical forms which result in a quite simple manufacture of the apparatus . In Fig. 5, blades 12 have triangular forms and counterblades 13 have a shape being similar to the form of moving blades 1 in Fig. 1. Nevertheless, the number of blades 12 and counter- blades 13 can be different, thus, the angle between blades 12 may differ from an angle 14 between ad acenτ counterblades In sense of the invention, the blades can be moved not only by a rotational but also by a translatory motion. This illus¬ trated with a preferred embodiment in Fig. 6, wherein moving blades 1 are attached to each other by pivotal joints 15 like members of an endless chain. This chain is guided by pulleys 16 and 17 round and round, and at least one of pulleys 16, 17 are rotationally driven. With this, moving blades 1 are for¬ warded with a continuous and uniform translatory motion, and they cooperate with stationary blades 2 fixed to the housing of the apparatus. An endless supporting belt or chain can also be used onto which moving blades 1 can be fixed. In this case, fingers 4 (Fig. 1) can also be applied on stationary blades 2. In. this case, too, two identical sets of blades can be provi¬ ded both of them being rotationally driven but in opposite directions. Therein, of course, fingers 4 can not be used. In both cases, blades move translatoryly in respect to each other when cutting the stems or spears of the plants. These translatory motions can also be reversed when the blades get edgeless . Fig. 7 illustrates an embodiment wherein four cutting units 18 as shown in Fig. 1 are mounted on a holding frame 1 side by side. With this, the working width of the apparatus can be increased. Each cutting unit can have its own individual driving means 20 having an electric, hydraulic or pneumatic motor. In another realization, cutting units 18 can be con- nected to a common source of mechanical energy of e. g. a greater working machine such as a tractor. In frame 19, a certain vertical dislocation of cutting units 18 is possible, and with this, the unevennesses of the ground can be followed, thus, the main hindrance against increasing the moving width is eliminated. Of course, any other pre- ferred embodiment can be mounted on frame 19 as a cutting unit 18. In Fig. 8, a cross section on line VIII-VIII in Fig. 7 is shown. On the bottom, it is closed by a slide shoe 21. Sta¬ tionary blades 2 with fingers 4 are arranged in a room closed on the upper side by a cover 22. To driving means 20, disk 3 holding moving blades 1 is connected. In Fig. 9 , the moment of cutting the stem of a plant 23 is illustrated. Moving blades 1 bend it to a certain amount and presses it against stationary blades 2 and, thus, it will be sheared. Thereafter, the cut plant 23 drops through frame 19 on the field and remains there until it will be collected. Using the principles of this invention, a quite simple lawn- mower can be constructed, a preferred embodiment of which is shown in Figs 10 and 11. It has two cutting units 18 formed as the embodiment shown in Fig. 1. Units 18 have moving blades 1 and stationary blades 2 with fingers 4. Moving blades 1 of each unit 18 is driven by a separate electric motor 24 but in opposite directions as shown by arrows 25 and 26. Motors 24 covered by conical housings 27 are fed from two accumulators 28 arranged under a cover 29- The lawn-mower has wheels 30 as well as hand lever 31 for being moved. To accu¬ mulators 28, a charger 32 and, also, solar cells 33 for energy supply can be provided. Under solar cells 33, a grass box 3 for collecting the cut grass is arranged. When accumulators 28 are charged by charger 32 or solar cells 33 and the cutting height is determined by adjusting wheels 30, moving blades 1 of respective cutting units 18 will be rotated in opposite directions. The grass cut as described previously will be gathered between conical housings 27 and forwarded to grass box 34. The experiments with the solution in this invention have proven that the energy consumption is 5 to 10 times smaller than with the conventional cutters. For the embodiment as shown in Figs. 10 and 11 and having a working width of about 50 cm and a working speed of 3 to 4 km/h, e. g. , the energy demand can be ' reduced to smaller than 300 W. With this, accu¬ mulators 28 supply a sufficient amount of energy and sman¬ power electric motors 24 can be used. The beneficial effects of such kind of a lawn—mower is obvious to the environment.

Claims: Claims : 1. A method for cutting stems or spears of plants, wherein the ste s or spears of plants is cut by two sets of blades being moved in relation to each other, c h a r a c ¬ t e r i z e d in that the relative motion of the two sets of blades resulting in cutting the stems or spears of stems is a continuous translatory or rotational motion. 2. A method as claimed in Claim 1, wherein the plants being cut are simultaneously gathered. 3 - A method as claimed in Claim 1 or 2, wherein the mo¬ tion resulting in cutting the stems or spears of stems is produced by individual drives. 4. A method as claimed in Claim 3, wherein the drives are powered by electricity. 5. An apparatus for cutting stems or spears of plants, wherein two sets of blades being moved in relation to each other are provided, c h a r a c t e r i z e d in that at least one of the two sets of blades (1, 2; 12, 13) is connec¬ ted to a drive causing a continuous translatory or rotational relative motion of the two sets of blades (1, 2; 12, 13). 6. An apparatus as claimed in Claim 5, wherein one of the two sets of blades (1, 2; 12, 13) is stationarily fixed to a housing of the apparatus. 7. An apparatus as claimed in Claim 6, wherein fingers (3) are attached to the blades (2) being stationarily fixed to the housing as extensions of the blades (2). 8. An apparatus as claimed in any of Claims 5 to 7, wherein the moving blades (1) are fixed on a disk (3) being connected to a rotational drive. 9. An apparatus as claimed in Claim 8, wherein the blades (2) being stationarily fixed are arranged in a half-circle facing a direction of movement of the apparatus, and tips of moving and stationary- blades (1, 2; 12, 13) are on the same diameter. 10. An apparatus as claimed in Claim 9, wherein the sta¬ tionary blades (2, 13) have triangular forms, and an acute angle of the triangles are ever increasing when departing from a middle axis (9) of the apparatus. 11. An apparatus as claimed in Claim 10, wherein the sta¬ tionary blades (2) are arranged symmetrically to the middle axis (9) of the apparatus. 12. An apparatus as claimed in any of Claims 5 to 7, whereixi the blades (1) being moved are fixed on an endless longitudinal support element guided by at least two pulleys (16, 17), at least one of which is connected to a rotational drive. 13. An apparatus as claimed in any of Claims 5 to 7, wherein the blades (2) being moved are pivotally jointed to each other like members of a chain and said chain guided by at least two pulleys !6, 17), at least one of which is con- nected to a rotational drive. 14. An apparatus as claimed in any of Claims 5 to 13, wherein the blades (1, 2; 12, 13) have two cutting edges (5 to 8). 15- An apparatus as claimed in Claim 14, wherein one of the blades (1; 13) have two parallel cutting edges (5, 6). 16. An apparatus as claimed in any of Claims 5 to 14, wherein the moving blades (1; 12) and the stationary blades (2; 13) have identical forms. 17. An apparatus as claimed in any of Claims 5 to 16, wherein more than one cutting units (18) are arranged side by side on a common holding frame (19) of the apparatus. 18. An apparatus as claimed in any of Claims 5 to 17, wherein the apparatus or the cutting units (18) have their own energy source and motor device connected to the energy source . 19- An apparatus as claimed in Claim 19 . wherein the ener¬ gy source is at least one accumulator (28) and, preferably, solar cells (33). 20. An apparatus as claimed in any of Claims 5 to 17, wherein the apparatus or the cutting units (18) are attached to an outer driving means moving, at the same tine, the appa¬ ratus .

Inventors: SULLER ATTILA, TOTH ARPAD, SULLER, ATTILA, TOTH, ARPAD
Applicants: SULLER ATTILA, TOTH ARPAD, SULLER, ATTILA, TOTH, ARPAD
Application year: 1989
Main classification: A01D34
IPC codes: A01D34