Cutting device with an alternating rotation cutting cutter

Abstract

Cutting device (1) comprising: - a cutting cutter (2) elongated around a main axis (20) and comprising at least one right-hand cutting tooth with a right-hand cutting edge oriented for clockwise cutting, and at least one left-hand cutting tooth with a left-hand cutting edge oriented for counterclockwise cutting; - a motorized drive device (3) comprising a mechanism for alternating the direction of rotation to drive the cutting cutter (2) in rotation alternately clockwise with a first angular amplitude and counterclockwise with a second angular amplitude. This cutting device has applications, including but not limited to, wood cutting, whether for pruning, trimming, or logging. Abstract figure: Figure 1

Description

Title of the invention: Cutting apparatus with a cutting cutter with alternating rotations. Technical field

[0001] The invention relates to a cutting device.

[0002] It relates more particularly to a cutting device comprising a cutting cutter and a motorized drive device which is mechanically coupled to the cutting cutter to drive it in rotation.

[0003] The invention finds application for the cutting and machining of wood, whether for pruning, trimming and logging work, and for carpentry and cabinetmaking work such as routing, grooving and chamfering. Previous technique

[0004] In the field of wood cutting, it is generally known to use chain saws, which are certainly functional, but which have drawbacks in terms of weight, size, energy consumption, chain lubrication requirements, and recurring problems with guide bar jamming. For at least these reasons, chain saws are impractical for work at height, on ladders, or using poles.

[0005] It is also known, for example from documents DE3818174A1, EP0240103A2 and FR2495435A1, to employ a cutting device comprising a cutting cutter and a motorized drive device that rotates the cutting cutter around its axis, where the cutting cutter has one or more cutting edges, all oriented for cutting in a single direction of rotation. Thus, in operation, the motorized drive device rotates the cutting cutter in this single direction of rotation, so that the cutting edge(s) perform their cutting function.

[0006] However, this type of cutting device has several disadvantages, the main one being that the cutting cutter, which is not mechanically guided and constrained against the wood, tends to creep laterally on the wood, making the cut difficult or even ineffective. Summary of the invention

[0007] An object of the invention is to provide a cutting device comprising a cutting cutter and a motorized drive device, which makes it possible to limit, or even prevent, the cutting cutter from creeping laterally, in order to allow a straight and penetrating cut.

[0008] To this end, the invention proposes a cutting device comprising: - a cutting cutter that is elongated around a main axis and comprises a cutting portion and a coupling portion, and - a motorized drive device which is mechanically coupled to the coupling portion of the cutting cutter to drive this cutting cutter in rotation around the main axis; said cutting device being characterized in that: - the cutting portion of the cutter comprises at least one right-hand cutting tooth with a straight cutting edge oriented for cutting in the clockwise direction of rotation of the cutter, and at least one left-hand cutting tooth with a left-hand cutting edge oriented for cutting in the counterclockwise direction of rotation of the cutter; and in that - the motorized drive device incorporates an alternating rotation direction reversal mechanism to drive the cutting cutter in rotation alternately clockwise with a first angular amplitude and counterclockwise with a second angular amplitude.

[0009] Thus, the invention proposes rotating the cutting cutter alternately in one direction and then the other, this cutting cutter being adapted for cutting in both directions of rotation thanks to its at least one right-hand cutting tooth and its at least one left-hand cutting tooth. As a result, the cutting cutter will not creep laterally and will easily penetrate the wood, cutting directly along a straight cutting groove, without deviating, following the direction of a slight penetration force for operator guidance.

[0010] In summary, this cutting device is based on the principle of alternating rotations of the cutting cutter, and therefore on cuts according to alternating directions of rotation.

[0011] A first aspect of this cutting device is therefore the geometry of the cutting cutter, with at least one cutting tooth on the right whose right cutting edge engages the cutting of a wood chip when the cutting cutter rotates clockwise (also called right rotation), and with at least one cutting tooth on the left whose left cutting edge engages the cutting of a wood chip when the cutting cutter rotates counterclockwise (also called left rotation).

[0012] The cutting edges of each of the cutting teeth may be straight and parallel to the main axis, or be wound in a helix with a pitch that is more or less large, for example twice the diameter of the cutting cutter.

[0013] A second aspect of this cutting device is the kinematics of the motorized drive device which ensures the cutting cutter is driven by alternating its rotation to the right (clockwise) then to the left (counterclockwise), and again to the right then to the left, and so on until the cutter stops. rotation. The rotation speed of the cutting cutter and the power of the motorized drive device can directly depend on the cutting parameters in the wood, hardness and length of the cut, which are related to the dimensions of the cutting cutter (diameter and length).

[0014] According to one possibility, the reciprocating motion of the cutting cutter is a sinusoidal rotational motion alternating in one direction and then the other. Also, the rotational speed of the cutting cutter follows a sinusoidal curve whose amplitude alternates between positive (which corresponds to a clockwise rotation) and negative (which corresponds to a counterclockwise rotation).

[0015] According to one characteristic, the first angular amplitude and the second angular amplitude are equivalent.

[0016] Thus, the angular amplitude is the same for both directions of rotation of the cutting cutter, to promote symmetry or regularity in the cut.

[0017] According to one possibility, the first angular amplitude and the second angular amplitude are each greater than or equal to 360 degrees.

[0018] Thus, the cutting cutter makes at least 1 complete turn with each rotation, for efficiency in cutting and speed.

[0019] According to another possibility, the first angular amplitude and the second angular amplitude are each less than or equal to 1440 degrees.

[0020] Thus, the cutting cutter makes a maximum of 4 complete turns, to avoid a deviation in the cut while allowing the wood chips to be expelled, which can in fact be easily extracted by centrifugal force, thus avoiding the generation of a jam.

[0021] According to another possibility, the first angular amplitude and the second angular amplitude are each between 540 and 1080 degrees.

[0022] Thus, the cutting cutter makes between 1.5 and 3 turns with each rotation, which is advantageous for obtaining a high cutting speed and expelling wood chips.

[0023] In a particular embodiment, the right cutting edge and the left cutting edge have the same cutting radius.

[0024] Advantageously, the cutting cutter includes at least one cutting height limiter having a limiting radius less than the cutting radius.

[0025] The function of this cutting limiter is to limit the height of the wood chips, this height being at most equal to the difference between the cutting radius and the limiting radius. For example, this difference can be on the order of 0.5 to 1.5 millimeters, or even between 0.6 and 1.0 millimeter.

[0026] In a particular embodiment, at least one cutting tooth on the right and at least one cutting tooth on the left have the same clearance angle between 6 and 20 degrees, and for example 15 degrees.

[0027] According to one possibility, at least one cutting tooth on the right and at least one cutting tooth on the left have the same cutting angle between 15 and 40 degrees.

[0028] According to one feature, at least one cutting tooth on the right and at least one cutting tooth on the left each have a front cutting face delimiting a front zone, and an opposite dorsal face delimiting a dorsal zone.

[0029] The cutting face of at least one right-hand cutting tooth corresponds to the cutting edge face when the cutter rotates clockwise, and the cutting face of at least one left-hand cutting tooth corresponds to the cutting edge face when the cutter rotates counterclockwise. These two cutting faces define the frontal area in which the wood chips are collected.

[0030] According to another possibility, the right cutting edge and the left cutting edge are angularly offset around the main axis by an opening angle between 90 and 270 degrees.

[0031] Thus, the right cutting edge and the left cutting edge can be offset by half a turn (opening angle of 180 degrees), or be offset by a quarter turn (opening angle of 90 or 270 degrees) or be between these two positions; these opening angles being advantageous for good penetration into the wood of the active tooth (the one that cuts) without hindrance from the inactive tooth (the one that does not cut).

[0032] According to a first variant, the opening angle is between 120 and 180 degrees.

[0033] In this first variant, at least one cutting height limiter may be located in the frontal area, which, as a reminder, is delimited by the two frontal faces.

[0034] According to one possibility, the at least one cutting height limiter comprises two cutting height limiters which are angularly offset around the main axis at an angle of 90 degrees and equidistant from the right cutting edge and the left cutting edge, respectively.

[0035] According to a second variant, the opening angle is 90 degrees.

[0036] In this second variant, at least one cutting height limiter may be located in the dorsal area.

[0037] According to one possibility, the at least one cutting height limiter comprises two cutting height limiters which are angularly offset around the main axis at an angle of 90 degrees and equidistant from the right cutting edge and the left cutting edge, respectively.

[0038] In one embodiment, the right cutting edge and the left cutting edge are straight and parallel to the main axis.

[0039] Alternatively, the right cutting edge and the left cutting edge are helical around the main axis.

[0040] In a particular embodiment, at least one cutting tooth on the right and at least one cutting tooth on the left are one piece with the cutting cutter.

[0041] In one embodiment, the cutting cutter comprises a central shaft centered on the main axis and cutting modules mounted end to end on the central shaft and rotationally coupled to this central shaft, where each of these cutting modules comprises at least one right-hand cutting tooth and / or at least one left-hand cutting tooth.

[0042] Thus, it is possible to manufacture cutting modules and then mount them on the central shaft to form the cutting cutter; each of the cutting modules fitting onto the central shaft and comprising one or more cutting teeth.

[0043] In a first variant, each of the cutting modules includes at least one right-hand cutting tooth and at least one left-hand cutting tooth.

[0044] Thus, each cutting module can cut in the clockwise direction of rotation and in the counterclockwise direction of rotation.

[0045] In a second embodiment, the cutting modules comprise several right-hand cutting modules, each comprising at least one right-hand cutting tooth (and no left-hand cutting teeth), and several left-hand cutting modules, each comprising at least one left-hand cutting tooth (and no right-hand cutting teeth), and the right-hand cutting modules are mounted alternately with the left-hand cutting modules

[0046] Thus, each right-hand cutting module can only cut in the clockwise direction of rotation, and each left-hand cutting module can only cut in the counterclockwise direction of rotation. In this second variant, it is therefore preferable for the cutting modules to be short, for example with lengths less than or equal to 10 millimeters, or even less than or equal to 5 millimeters.

[0047] According to one possibility, each of the cutting modules comprises several straight grooves, parallel to the main axis and extending over the entire length, of which at least one straight groove receives a cutting tooth on the right or left which protrudes axially from the cutting module and at least one straight groove which partially receives at least one cutting tooth on the left or right of an adjacent cutting module.

[0048] Thus, the rotational coupling between the cutting modules is achieved by means of the engagement of a cutting tooth of one cutting module inside a straight groove of at least one other cutting module.

[0049] In a particular embodiment, the motorized drive device comprises a rotary motor driving a drive shaft in rotation in a single motor direction, and the mechanism for alternating the direction of rotation comprises an eccentric system driven in rotation by the drive shaft and converting the rotation of the drive shaft into an oscillating rotary motion of an oscillating rocker arm, which oscillating rocker arm having a toothed section which is in mesh with a pinion integral with the cutting cutter.

[0050] Thus, the motorized drive device uses the rotary motor which rotates in a single direction of rotation, and the alternating rotation direction reversal mechanism allows this single-direction rotation to be converted into alternating rotations to the right (clockwise) and to the left (counterclockwise) of the oscillating rocker and therefore of the cutting cutter.

[0051] This mechanism advantageously allows for high rotational speeds for the cutting cutter, at least 5000 rpm. The ratio between the toothed section of the oscillating rocker arm and the pinion fixed to the cutting cutter makes it possible to set a multiplication ratio so that each oscillation of the oscillating rocker arm is converted into given first and second angular amplitudes, for example between 1.5 and 4 revolutions of the cutting cutter, in one direction and the other.

[0052] According to one feature, the eccentric system comprises a toothed wheel meshing with the drive shaft, either directly or via a reducer or multiplier, and a connecting rod having a first end articulated on the toothed wheel and a second end articulated on the oscillating rocker arm.

[0053] According to one feature, the motorized drive device includes a flywheel coupled to the motor shaft; in order to reduce vibrations and improve cutting accuracy.

[0054] According to one feature, the motorized drive device includes a variator for varying the rotational speed of the motor shaft, in particular to allow the speed to be gradually increased at start-up, manually or automatically, up to a variable nominal speed following an acceleration ramp.

[0055] Advantageously, the rotary motor is an electric motor, such as, for example, a brushless DC electric motor. The cutting device may optionally include an electric battery powering the rotary electric motor, thus forming a portable power tool. Brief description of the drawings

[0056] Other features and advantages of the present invention will become apparent from the following detailed description, including non-limiting examples of implementation, with reference to the accompanying figures in which:

[0057] [Fig-1] is a schematic view of a cutting device with a pole telescopic;

[0058] [Fig.2] is a schematic view of a cutting device with a handle;

[0059] [Fig.3] is a schematic cross-sectional view of a cutting cutter equipped with a cutting tooth on the right and a cutting tooth on the left whose cutting edges are straight, during a rotation to the right (in a clockwise direction);

[0060] [Fig.4] is a schematic cross-sectional view of the cutting cutter of [Fig.3], during a left rotation (in a counterclockwise direction);

[0061] [Fig.5] is a schematic cross-sectional view of another cutting cutter having a cutting tooth on the right and a cutting tooth on the left whose cutting edges are straight, during a right-hand rotation (clockwise);

[0062] [Fig.6] is a schematic cross-sectional view of another cutting cutter having a cutting tooth on the right and a cutting tooth on the left whose cutting edges are straight, during a right-hand rotation (in a clockwise direction);

[0063] [Fig.7] is a schematic view of two cutting cutters comprising stacked cutting modules;

[0064] [Fig.8] is a schematic view of a cutting cutter equipped with a cutting tooth on the right and a cutting tooth on the left whose cutting edges are helical;

[0065] [Fig.9] is a schematic zoomed view of the tip of the cutting cutter of [Fig.8];

[0066] [Fig. 10] is a schematic view of a motorized drive device equipped with a mechanism for alternating the direction of rotation.

[0067] [Detailed description of several embodiments of the invention]

[0068] With reference to Figures 1 and 2, a cutting device 1 comprises: - a cutting cutter 2 which is elongated around a main axis 20 and which comprises a cutting portion 21 and a coupling portion 22; and - a motorized drive device 3 which is mechanically coupled to the coupling portion 22 of the cutting cutter 2 to drive this cutting cutter 2 in rotation around the main axis 20.

[0069] With reference to [Fig. 10], the motorized drive device 3 incorporates an alternating rotation direction reversal mechanism 30, disposed inside a housing 31 and designed to drive the cutting cutter 2 in rotation alternately in a clockwise direction SI around the main axis 20 with a first angular amplitude and in a counterclockwise direction S2 with a second angular amplitude, which is equivalent to the first angular amplitude.

[0070] The first angular amplitude and the second angular amplitude are each greater than or equal to 360 degrees (i.e. 1 turn) and less than or equal to 1440 degrees (i.e. 4 turns), and for example between 540 (1 and a half turns) and 1080 degrees (i.e. 3 turns).

[0071] Thus, the motorized drive device 3 ensures a drive of the cutting cutter 2 by alternating its rotation in the clockwise direction SI on the first angular amplitude (between 1 and 4 turns on the right) then in the counterclockwise direction S2 on the second angular amplitude (between 1 and 4 turns on the left), and again on the right then on the left, and so on until the rotation stops.

[0072] The cutting portion 21 of the cutting cutter 2 comprises at least one right-hand cutting tooth 23 having a right-hand cutting edge 230 oriented for a clockwise cut S1 of rotation of the cutting cutter 2, and at least one left-hand cutting tooth 24 having a left-hand cutting edge 240 oriented for a counterclockwise cut S2 of rotation of the cutting cutter 2.

[0073] The right cutting edge(s) 230 and the left cutting edge(s) 240 have the same cutting radius, illustrated by a cutting circle Cl centered on the main axis 20.

[0074] Thus, the cutting cutter 2 has a unique configuration with one or more right-hand cutting teeth 23 and one or more left-hand cutting teeth 24, each equipped with corresponding cutting edges 230, 240, allowing cutting in both directions of rotation SI, S2 of the cutting cutter 2. Furthermore, the motorized drive device 3 allows rotation of the cutting cutter 2 alternately in both directions SI, S2, with equivalent angular amplitudes in both directions. This configuration offers high flexibility and efficiency in cutting operations.

[0075] In the embodiments of Figures 3 to 7, the cutting teeth 23, 24 are straight and parallel to the main axis 20, so that their respective cutting edges 230, 240 are also straight and parallel to the main axis 20.

[0076] In the embodiments of Figures 8 and 9, the cutting teeth 23, 24 are helical and wrap around the main axis 20, so that their respective cutting edges 230, 240 are also helical around the main axis 20.

[0077] According to a first embodiment, the cutting teeth 23, 24 are monobloc with the cutting cutter 2, as in the example illustrated in Figures 8 and 9, with cutting teeth 23, 24 which can be obtained by machining.

[0078] According to a second embodiment, the cutting teeth 23, 24 are attached and fixed to a shaft 25, as in the examples illustrated in Figures 3 to 6. This fixing of the cutting teeth 23, 24 to the shaft 25 can be achieved by welding, brazing, crimping or gluing.

[0079] In a particular embodiment, the cutting cutter 2 comprises a single right-hand cutting tooth 23 extending over the entire length of the cutting portion 21, and a single left-hand cutting tooth 24 extending over the entire length of the cutting portion 21.

[0080] In another particular embodiment, the cutting cutter 2 comprises several right-hand cutting teeth 23 extending over different sections of the cutting portion 21, and several left-hand cutting teeth 24 extending over different sections of the cutting portion 21. Between two adjacent or successive sections of the cutting portion 21, the right-hand cutting teeth 23 can be aligned or angularly offset, and similarly the left-hand cutting teeth 24 can be aligned or angularly offset.

[0081] In a particular embodiment illustrated in [Fig.7], which is a so-called modular or composite embodiment, the cutting cutter 2 comprises: - a central shaft 26 centered on the main axis 20 and which is rotationally fixed with the coupling portion 22 (for example by being monobloc with it); and - cutting modules 27 mounted end to end on the central shaft 26 and rotationally coupled to this central shaft 26, so that the motorized drive device 3 ensures a drive of the central shaft 26 and the cutting modules 27.

[0082] Each of these cutting modules 27 is tubular and comprises a sleeve-shaped body 270, and further comprises at least one right-hand cutting tooth 23 and / or at least one left-hand cutting tooth 24 integral with the sleeve 270. Thus, the cutting modules 27 are stacked around the central shaft 26, one after the other, and are driven in rotation with the central shaft 26. These cutting modules 27 thus together form the cutting portion 21.

[0083] One advantage of this modular or composite design is the significant reduction in the production cost of the cutting portion 21 of the cutting cutter 2, thanks to the multiplication of small, simplified cutting modules 27 that are easy to machine or mass-produce. It also allows the length of the cutting cutter 2 to be easily adjusted by selecting a longer or shorter central shaft 26 and adapting the number of cutting modules 27 accordingly.

[0084] In a first embodiment of this modular or composite design, each of the cutting modules 27 comprises at least one right-hand cutting tooth 23 and at least one left-hand cutting tooth 24, and for example comprises one right-hand cutting tooth 23 and one left-hand cutting tooth 24. Between two adjacent or successive cutting modules 27, the right-hand cutting teeth 23 may be aligned or angularly offset, and similarly the left-hand cutting teeth 24 may be aligned or angularly offset. Thus, each of the cutting modules 27 is capable of performing a clockwise cut S1 and a counterclockwise cut S2.

[0085] In a second embodiment of this modular or composite structure, the cutting modules 27 comprise: - several straight cutting modules, each supporting at least one right-hand cutting tooth 23 and no left-hand cutting teeth 24, and - several left-hand cutting modules, each supporting at least one left-hand cutting tooth 24 and no right-hand cutting teeth 23.

[0086] In this second mode, the right-cutting modules are mounted alternately with the left-cutting modules, i.e., a right-cutting module, then a left-cutting module, then a right-cutting module, then a left-cutting module, and so on. In this second mode, the cutting modules 27 preferably have the same length (measured along the main axis 20), and this length is advantageously less than or equal to 20 millimeters, or even less than or equal to 15 millimeters.

[0087] In the two embodiments illustrated in [Fig.7], the central shaft 26 terminates in a thread 260 onto which a cap nut 261 is screwed for tightening the stack of cutting modules 27 against an opposite shoulder 262; the first of the cutting modules 27 coming against this shoulder 262. The cap nut 261 is a locking nut suitable for preventing loosening during rotation in contact with the wood, and it can alternatively be replaced by a different clamping system fulfilling the same clamping and locking functions or by a pin system.

[0088] In the embodiment of [Fig.7](a) on the left, the cutting teeth 23, 24 of the cutting modules 27 extend axially from the respective sleeves 270, so as to be cantilevered to bear against a bearing face provided on the adjacent sleeve(s) 270, in order to transmit the rotational torque from one cutting module 27 to the other, whether in the clockwise direction SI and in the counterclockwise direction S2.

[0089] In the embodiment of [Fig. 7](b) on the right, the sleeves 270 of the cutting modules 27 are coupled in pairs by respective tenon / mortise joints 272, angularly offset from the cutting teeth 23, 24 which do not protrude axially from the respective sleeves 270. The first of the cutting modules 27 is also coupled to the coupling portion 22 by a tenon / mortise joint 273.

[0090] Regarding the conformation of the cutting teeth 23, 24, referring to [Fig.3]: - the cutting tooth or each right 23 and the cutting tooth or each left 24 have the same clearance angle Al between 6 and 20 degrees, and for example 15 degrees; - each cutting tooth on the right 23 and each cutting tooth on the left 24 have the same cutting angle A2 between 15 and 40 degrees, and for example 30 degrees; - the right cutting edge 230 and the left cutting edge 240 are angularly offset around the main axis 20 according to an opening angle A3 between 90 and 270 degrees.

[0091] In the example in Figures 3 and 4, the opening angle A3 is 90 degrees, while in the examples in Figures 5 and 6, the opening angle A3 is 180 degrees.

[0092] Referring to [Fig.4], the cutting tooth on the right 23 and the cutting tooth on the left 24 each have a front cutting face 231, 241 delimiting a front zone 28, and an opposite dorsal face 232, 242 delimiting a dorsal zone 29.

[0093] Furthermore, the cutting cutter 2 includes at least one cutting height limiter having a limiting radius less than the cutting radius; this limiting radius being symbolized by a limiting circle C2.

[0094] In the example of Figures 3 and 4, the at least one cutting height limiter comprises two cutting height limiters 40 formed of two heels located in the dorsal area 29, and which are angularly offset around the main axis 20 at an angle of 90 degrees and at respective equidistances from the right cutting edge 230 and the left cutting edge 240.

[0095] In the example of [Fig.5], the at least one cutting height limiter comprises two cutting height limiters 41 formed of two heels located in the front area 28, and which are angularly offset around the main axis 20 at an angle of 90 degrees and at respective equidistances from the right cutting edge 230 and the left cutting edge 240.

[0096] In the example of [Fig.6], the at least one cutting height limiter comprises a single cutting height limiter 42 formed of a heel located in the front area 28, and which is equidistant from the right cutting edge 230 and the left cutting edge 240.

[0097] In the examples of Figures 5 and 6 where the opening angle A3 is 180 degrees, when one of the cutting teeth is active (i.e. it notches the wood and forms a chip 100; the cutting tooth on the right 23 in the illustrated examples), at the same time, the inactive cutting tooth positioned at 180° and intended to cut in the other direction of rotation (the cutting tooth on the left 24 in the illustrated examples), will automatically disengage from the wood, and thus will not be able to cause the active cutting tooth to bottom out, which will engage the cut with the height of the chip 100, this height of the chip 100 being limited in the cut by the chip height limiter 41 or 42 arranged at 90° in front of the active cutting tooth.

[0098] In the example of Figures 3 and 4, where the opening angle A3 is 90 degrees, the configuration of the two cutting edges 230, 240 at 90° to each other and on the same cutting circle Cl allows that, when one of the cutting teeth is active (i.e., it is notching the wood and forming a chip 100; the right-hand cutting tooth 23 in the example illustrated in [Fig. 3]), at the same time, the inactive cutting tooth positioned at 90° and intended to cut in the opposite direction of rotation (the left-hand cutting tooth 24 in the example illustrated in [Fig. 3]) disengages from the cutting diameter. This disengagement of the inactive cutting tooth is caused by the cutting force from the motor torque of the motorized drive device 3, and thus does not allow limit the cutting depth of the active cutting tooth. In this case, the chip height 100 is limited in the cut by the chip height limiter 40 located at 90° to the rear of the active tooth, which has a radius smaller than the cutting radius.

[0099] With reference to Figures 1 and 2, the motorized drive device 3 comprises a rotary motor 32 mounted on the housing 31. In the version of [Fig.1], a telescopic pole 51 is mounted on this housing 31, while in the version of [Fig.2], a handling handle 52 is mounted on the housing 31.

[0100] With reference to [Fig. 10], the rotary motor 32 drives a drive shaft 33 in rotation in a single direction S3, with a motor speed that can be on the order of 20,000 to 40,000 rpm. A flywheel can be coupled to the drive shaft 33 to ensure smooth operation and to balance the reciprocating sinusoidal motion of the mechanism, thereby limiting vibrations and reducing energy consumption.

[0101] The alternating rotation direction reversal mechanism 30 comprises an eccentric system 34 driven in rotation by the drive shaft 33 and converting the rotation of the drive shaft 33 into an oscillating rotary motion of an oscillating rocker 35, and this oscillating rocker 35 is coupled in rotation with the coupling portion 22 of the cutting cutter 2.

[0102] In a particular embodiment, the eccentric system 34 comprises a toothed wheel 36 meshing with the drive shaft 33, either directly or via a reducer or a multiplier. It is also possible to provide a gear reducer with a reduction ratio from 1 to 1 / 10

[0103] The eccentric system 34 also includes a connecting rod 37 having a first end 371 articulated on the toothed wheel 36 and a second end 372 articulated on the oscillating balance 35. Thus, the drive shaft 33 drives the toothed wheel 36 in rotation and the connecting rod 37 makes a reciprocating movement so that its second end 372 makes the oscillating balance 35 oscillate which pivots successively to the right and to the left. In the illustrated example, the oscillating balance 35 makes a half-rotation of 90 degrees to the right on the descent of the connecting rod 37, then a half-rotation of 90 degrees to the left on the ascent of the connecting rod 37. Thus, the amplitude of the oscillations of the oscillating balance 35 is 90 degrees, but it can be greater and for example be between 90 and 120 degrees.

[0104] The oscillating rocker arm 35 is rotationally coupled with the coupling portion 22 of the cutting cutter 2, and more specifically the oscillating rocker arm 35 has a toothed section which meshes with a pinion 38 fixed to the coupling portion 22. The ratio between the toothed section of the oscillating rocker arm 35 and the pinion 38 makes it possible to obtain a multiplication ratio, for example, between 6 and 8, in order to allow the oscillating rocker arm 35, in its oscillation, to 90 degrees (or even 120 degrees) to obtain on the pinion 38, and therefore on the cutting cutter 2, an alternating rotation of 2 turns to the right then 2 turns to the left.

[0105] According to an advantageous option, the motorized drive device 3 includes a variable speed drive for varying the rotational speed of the motor shaft 33. For example, this variable speed drive will stabilize the cut and prevent kickback during startup. Indeed, at startup, the rotational speed can be increased gradually and automatically until it reaches a nominal speed, following an acceleration ramp, the duration of which can be programmed by the operator, for example, from 0.3 to 1 second.

Claims

Demands

1. Cutting device (1) comprising: - a cutting cutter (2) which is elongated around a main axis (20) and which has a cutting portion (21) and a coupling portion (22), and - a motorized drive device (3) which is mechanically coupled to the coupling portion (22) of the cutting cutter (2) to drive this cutting cutter (2) in rotation around the main axis (20); said cutting device (1) being characterized in that: - the cutting portion (21) of the cutting cutter (2) comprises at least one right-hand cutting tooth (23) provided with a right-hand cutting edge (230) oriented for a cut in a clockwise direction (SI) of rotation of the cutting cutter (2), and at least one left-hand cutting tooth (24) provided with a left-hand cutting edge (240) oriented for a cut in a counterclockwise direction (S2) of rotation of the cutting cutter (2);and in that - the motorized drive device (3) incorporates an alternating rotation direction reversal mechanism (30) to drive the cutting cutter (2) in rotation alternately clockwise (S1) with a first angular amplitude and counterclockwise (S2) with a second angular amplitude.;

2. Cutting apparatus (1) according to claim 1, wherein the first angular amplitude and the second angular amplitude are equivalent.

3. Cutting apparatus (1) according to claim 1 or 2, wherein the first angular amplitude and the second angular amplitude are each greater than or equal to 360 degrees.

4. Cutting apparatus (1) according to any one of the preceding claims, wherein the first angular amplitude and the second angular amplitude are each less than or equal to 1440 degrees.

5. Cutting apparatus (1) according to claims 3 and 4, wherein the first angular amplitude and the second angular amplitude are each between 540 and 1080 degrees.

6. Cutting apparatus (1) according to any one of the preceding claims, wherein the right cutting edge (230) and the left cutting edge (240) have the same cutting radius.

7. Cutting device (1) according to claim 6, wherein the cutting cutter (2) comprises at least one cutting height limiter (40; 41; 42) having a limiting radius less than the cutting radius.

8. Cutting apparatus (1) according to any one of the preceding claims, wherein at least one right-hand cutting tooth (23) and at least one left-hand cutting tooth (24) have the same clearance angle (Al) between 6 and 20 degrees.

9. Cutting device (1) according to any one of the preceding claims, wherein at least one right-hand cutting tooth (23) and at least one left-hand cutting tooth (24) have the same cutting angle (A2) between 15 and 40 degrees.

10. Cutting apparatus (1) according to any one of the preceding claims, wherein at least one right-hand cutting tooth (23) and at least one left-hand cutting tooth (24) each have a front cutting face (241) delimiting a front zone (28), and an opposite back face (242) delimiting a back zone (29).

11. Cutting apparatus (1) according to any one of the preceding claims, wherein the right cutting edge (230) and the left cutting edge (240) are angularly offset around the main axis (20) by an opening angle (A3) between 90 and 270 degrees.

12. Cutting apparatus (1) according to claim 11, wherein the opening angle (A3) is between 120 and 180 degrees.

13. Cutting device (1) according to claims 7, 10 and 12, wherein at least one cutting height limiter (41; 42) is located in the front area (28).

14. Cutting device (1) according to claim 13, wherein the at least one cutting height limiter comprises two cutting height limiters (41) which are angularly offset around the main axis (20) at an angle of 90 degrees and equidistant respectively from the right cutting edge (230) and the left cutting edge (240).

15. Cutting apparatus (1) according to claim 10, wherein the opening angle (A3) is 90 degrees.

16. Cutting device (1) according to claims 7, 10 and 15, wherein at least one cutting height limiter (40) is located in the dorsal area (29).

17. Cutting device (1) according to claim 16, wherein the at least one cutting height limiter comprises two cutting height limiters (40) which are angularly offset around the main axis (20) at an angle of 90 degrees and equidistant respectively from the right cutting edge (230) and the left cutting edge (240).

18. Cutting apparatus (1) according to any one of claims 1 to 17, wherein the right cutting edge (230) and the left cutting edge (240) are straight and parallel to the main axis (20).

19. Cutting apparatus (1) according to any one of claims 1 to 17, wherein the right cutting edge (230) and the left cutting edge (240) are helical about the main axis (20).

20. Cutting device (1) according to any one of claims 1 to 19, wherein at least one right-hand cutting tooth (23) and at least one left-hand cutting tooth (24) are integral with the cutting cutter (2).

21. Cutting apparatus (1) according to any one of claims 1 to 19, wherein the cutting cutter (2) comprises a central shaft (26) centered on the main axis (20) and cutting modules (27) mounted end to end on the central shaft (26) and rotationally coupled to this central shaft (26), wherein each of said cutting modules (27) comprises at least one right-hand cutting tooth (23) and / or at least one left-hand cutting tooth (24).

22. Cutting device (1) according to claim 21, wherein each of the cutting modules (27) comprises at least one right-hand cutting tooth (23) and at least one left-hand cutting tooth (24).

23. Cutting apparatus (1) according to claim 21, wherein the cutting modules (27) comprise several right-hand cutting modules, each comprising at least one right-hand cutting tooth (23), and several left-hand cutting modules, each comprising at least one left-hand cutting tooth (24), and the right-hand cutting modules are mounted alternately with the left-hand cutting modules.

24. Cutting apparatus (1) according to any one of the preceding claims, wherein the motorized drive device (3) comprises a rotary motor (32) driving a drive shaft (33) in rotation in a single motor direction (S3), and the alternating rotation direction reversal mechanism (30) includes an eccentric system (34) driven in rotation by the motor shaft (33) and converting the rotation of the motor shaft (33) into an oscillating rotary motion of an oscillating rocker arm (35), which oscillating rocker arm (35) having a toothed section which is in mesh with a pinion (38) integral with the cutting cutter (2).

25. Cutting apparatus (1) according to claim 24, in which the eccentric system (34) comprises a toothed wheel (36) meshed with the drive shaft (33), either directly or via a reducer or multiplier, and a connecting rod (37) having a first end (371) articulated on the toothed wheel (36) and a second end (372) articulated on the oscillating rocker arm (35).

26. Cutting apparatus (1) according to claim 24 or 25, wherein the motorized drive device (3) comprises a flywheel coupled to the motor shaft (33).

27. ​​Cutting device (1) according to any one of claims 24 to 26, wherein the motorized drive device (3) includes a variator for varying the rotational speed of the motor shaft (33).

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