Cutting apparatus having a milling cutter with alternating rotations

Abstract

The invention relates to a cutting apparatus (1) comprising: - a milling cutter (2) that is elongate about a main axis (20) and comprises at least one right cutting tooth provided with a right cutting edge oriented to cut in a clockwise direction of rotation, and at least one left cutting tooth provided with a left cutting edge oriented to cut in an anticlockwise direction of rotation; - a motorised drive device (3) comprising a mechanism for alternately reversing the direction of rotation in order to rotate the milling cutter (2) alternately in the clockwise direction with a first angular amplitude and in the anticlockwise direction with a second angular amplitude. This cutting apparatus can be used, in a non-limiting manner, for cutting wood, whether for pruning, trimming or logging tasks.

Description

[0001] DESCRIPTION

[0002] TITLE: Cutting device with an alternating rotation cutting cutter

[0003] [Technical field]

[0004] The invention relates to a cutting device.

[0005] It relates more specifically 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.

[0006] 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.

[0007] [State of the art]

[0008] In the field of logging, chain saws are commonly used. While certainly functional, they have drawbacks in terms of weight, bulk, energy consumption, chain lubrication requirements, and recurring problems with guide bar jamming. For at least these reasons, chain saws are impractical for working at height, on ladders, or using poles.

[0009] 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, so that the cutting edge(s) perform their cutting function.

[0010] 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.

[0011] [Summary of the invention]

[0012] One aim 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.

[0013] To this end, the invention proposes a cutting device comprising:

[0014] - a cutting cutter that is elongated around a main axis and comprises a cutting portion and a coupling portion, and

[0015] - 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:

[0016] - 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

[0017] - 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.

[0018] Thus, the invention proposes rotating the cutter alternately in one direction and then the other, this 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 cutter will not creep laterally and will easily penetrate the wood, cutting directly along a straight groove without deviating, following the direction of a slight penetration force for operator guidance.

[0019] 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.

[0020] 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).

[0021] The cutting edges of each of the cutting teeth can 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.

[0022] A second aspect of this cutting device is the kinematics of the motorized drive system, which drives the cutter by alternating its rotation clockwise and counterclockwise, then clockwise and counterclockwise again, and so on until it stops. The cutter's rotational speed and the power of the motorized drive system can be directly adjusted according to the cutting parameters in the wood, such as the hardness and length of the cut, which are related to the cutter's dimensions (diameter and length).

[0023] According to one possibility, the reciprocating motion of the cutting cutter is a sinusoidal rotational motion alternating in one direction and then the other. Therefore, the rotational speed of the cutting cutter follows a sinusoidal curve whose amplitude alternates between positive (corresponding to a clockwise rotation) and negative (corresponding to a counterclockwise rotation).

[0024] According to one characteristic, the first angular amplitude and the second angular amplitude are equivalent.

[0025] Thus, the angular amplitude is the same for both directions of rotation of the cutting cutter, to promote symmetry or regularity in the cut.

[0026] According to one possibility, the first angular amplitude and the second angular amplitude are each greater than or equal to 360 degrees.

[0027] Thus, the cutting cutter makes at least 1 complete turn with each rotation, for efficiency in cutting and speed.

[0028] According to another possibility, the first angular amplitude and the second angular amplitude are each less than or equal to 1440 degrees.

[0029] 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.

[0030] According to another possibility, the first angular amplitude and the second angular amplitude are each between 540 and 1080 degrees.

[0031] Thus, the cutting cutter makes between 1.5 and 3 revolutions with each rotation, which is advantageous for achieving a high cutting speed and removing wood chips. In a particular design, the right and left cutting edges have the same cutting radius.

[0032] Advantageously, the cutting cutter includes at least one cutting height limiter having a limiting radius less than the cutting radius.

[0033] This cutting limiter's function 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.

[0034] 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.

[0035] 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.

[0036] According to one characteristic, 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.

[0037] The cutting face of at least one right-hand cutting tooth corresponds to the leading face of the cut when the cutter rotates clockwise, and the cutting face of at least one left-hand cutting tooth corresponds to the leading face of the cut when the cutter rotates counterclockwise. These two cutting faces define the frontal area where the wood chips collect.

[0038] 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.

[0039] 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).

[0040] According to one variant, the opening angle is between 120 and 180 degrees.

[0041] In this first variant, at least one cutting height limiter can be located in the front zone, which, as a reminder, is delimited by the two front faces. According to one possibility, the at least one cutting height limiter comprises two cutting height limiters that are angularly offset around the main axis at an angle of 90 degrees and equidistant from the right and left cutting edges, respectively.

[0042] According to a second variant, the opening angle is 90 degrees.

[0043] In this second variant, at least one cutting height limiter can be located in the dorsal area.

[0044] 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.

[0045] In a design, the right cutting edge and the left cutting edge are straight and parallel to the main axis.

[0046] Alternatively, the right cutting edge and the left cutting edge are helical around the main axis.

[0047] In a particular embodiment, at least one cutting tooth on the right and at least one cutting tooth on the left are integral with the cutting cutter.

[0048] 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.

[0049] 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.

[0050] 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.

[0051] Thus, each cutting module can cut in the clockwise direction of rotation and in the counterclockwise direction of rotation.

[0052] In a second variant, the cutting modules comprise several right-hand cutting modules, each with at least one right-hand cutting tooth (and no left-hand cutting teeth), and several left-hand cutting modules, each with at least one left-hand cutting tooth (and no right-hand cutting teeth). The right-hand cutting modules are mounted alternately with the left-hand cutting modules. 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. In this second variant, it is therefore preferable for the cutting modules to be short, for example, with lengths of 10 millimeters or less, or even 5 millimeters or less.

[0053] 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.

[0054] Thus, the rotational coupling between the cutting modules is achieved by engaging a cutting tooth of one cutting module inside a straight groove of at least one other cutting module.

[0055] In a particular embodiment, the motorized drive device includes a rotary motor driving a drive shaft in rotation in a single motor direction, and the alternating reversal mechanism of the direction of rotation includes 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.

[0056] 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 right (clockwise) and left (counterclockwise) rotations of the oscillating pendulum and therefore of the cutting cutter.

[0057] 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 attached to the cutting cutter allows for a multiplication ratio to be set 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 rotations of the cutting cutter, in one direction and then the other.

[0058] According to one characteristic, the eccentric system includes 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.

[0059] 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.

[0060] 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.

[0061] Advantageously, the rotary motor is an electric motor, such as a brushless DC motor. The cutting attachment may optionally include a battery powering the rotary motor, thus forming a portable power tool.

[0062] [Brief description of the figures]

[0063] Other features and advantages of the present invention will become apparent from the detailed description below, along with non-limiting examples of implementation, made with reference to the accompanying figures in which:

[0064] [Fig 1] is a schematic view of a cutting device with a telescopic pole;

[0065] [Fig 2] is a schematic view of a cutting device with a handle;

[0066] [Fig 3] is a schematic cross-sectional view of a cutting cutter with a cutting tooth on the right and a cutting tooth on the left whose cutting edges are straight, during a right-hand rotation (clockwise);

[0067] [Fig 4] is a schematic cross-sectional view of the cutting cutter in Figure 3, during a left rotation (in a counterclockwise direction);

[0068] [Fig 5] is a schematic cross-sectional view of another cutting cutter equipped with a cutting tooth on the right and a cutting tooth on the left whose cutting edges are straight, during a right-hand rotation (clockwise);

[0069] [Fig 6] is a schematic cross-sectional view of another cutting cutter equipped with a cutting tooth on the right and a cutting tooth on the left whose cutting edges are straight, during a right-hand rotation (clockwise);

[0070] [Fig 7] is a schematic view of two cutting cutters comprising stacked cutting modules; [Fig 8] is a schematic view of a cutting cutter with a cutting tooth on the right and a cutting tooth on the left whose cutting edges are helical;

[0071] [Fig 9] is a schematic zoomed view of the tip of the cutting cutter in Figure 8;

[0072] [Fig 10] is a schematic view of a motorized drive device equipped with a mechanism for alternating the direction of rotation.

[0073] [Detailed description of several embodiments of the invention]

[0074] With reference to Figures 1 and 2, a cutting device 1 comprises:

[0075] - 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

[0076] - 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.

[0077] With reference to Figure 10, the motorized drive device 3 incorporates an alternating rotation direction reversal mechanism 30, arranged 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.

[0078] 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).

[0079] 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 to the right) then in the counterclockwise direction S2 on the second angular amplitude (between 1 and 4 turns to the left), and again to the right then to the left, and so on until the rotation stops.

[0080] The cutting portion 21 of the cutting cutter 2 comprises at least one right-hand cutting tooth 23 with a right-hand cutting edge 230 oriented for a clockwise cutting direction SI of the cutting cutter 2's rotation, and at least one left-hand cutting tooth 24 with a left-hand cutting edge 240 oriented for a counterclockwise cutting direction S2 of the cutting cutter 2's rotation. The right-hand cutting edge(s) 230 and the left-hand cutting edge(s) 240 have the same cutting radius, illustrated by a cutting circle Cl centered on the main axis 20.

[0081] 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 the cutting cutter 2 to rotate alternately in both directions SI, S2, with equivalent angular amplitudes in both directions. This configuration offers high flexibility and efficiency in cutting operations.

[0082] 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.

[0083] 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.

[0084] 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.

[0085] 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 carried out by welding, brazing, crimping or gluing.

[0086] In a particular embodiment, the cutting cutter 2 includes 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.

[0087] 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. In a particular embodiment illustrated in Figure 7, which is a so-called modular or composite embodiment, the cutting cutter 2 comprises:

[0088] - a central shaft 26 centered on the main axis 20 and which is rotationally fixed to the coupling portion 22 (for example, by being a single unit with it); and

[0089] - cutting modules Tl mounted end to end on the central shaft 26 and coupled in rotation 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.

[0090] Each of these cutting modules Tl is tubular and comprises a sleeve-shaped body 270, and it further comprises at least one right-hand cutting tooth 23 and / or at least one left-hand cutting tooth 24 integral(s) with the sleeve 270. Thus, the cutting modules Tl are stacked around the central shaft 26, one after the other, and are driven in rotation with the central shaft 26. These cutting modules Tl together thus form the cutting portion 21.

[0091] One advantage of this modular or composite design is the significant reduction in the production cost of the cutting portion 21 of the cutter 2, thanks to the increased use of small, simplified cutting modules Tl, which are easy to machine or mass-produce. It also allows for easy adjustment of the length of the cutter 2 by selecting a longer or shorter central shaft 26 and adjusting the number of cutting modules Tl accordingly.

[0092] In a first embodiment of this modular or composite design, each cutting module Tl 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 Tl, 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 cutting module Tl is capable of performing a clockwise cut SI and a counterclockwise cut S2.

[0093] In a second mode of this modular or composite implementation, the Tl cutting modules include:

[0094] - several straight cutting modules, each supporting at least one right-hand cutting tooth 23 and no left-hand cutting teeth 24, and

[0095] - several left-hand cutting modules, each supporting at least one left-hand cutting tooth 24 and no right-hand cutting teeth 23.

[0096] In this second mode, the right-cutting modules are mounted alternately with the left-cutting modules, i.e., one right-cutting module, then one left-cutting module, then one right-cutting module, then one left-cutting module, and so on. In this second mode, the cutting modules Tl 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.

[0097] In the two embodiments illustrated in Figure 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 Tl against an opposite shoulder 262; the first of the cutting modules Tl comes to rest 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 be replaced alternatively by a different clamping system fulfilling the same clamping and locking functions or by a pin system.

[0098] In the realization of Figure 7(a) on the left, the cutting teeth 23, 24 of the cutting modules Tl extend axially beyond 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 Tl to the other, whether in the clockwise direction SI and in the counterclockwise direction S2.

[0099] In the embodiment shown in Figure 7(b) on the right, the sleeves 270 of the cutting modules T1 are coupled in pairs by respective tenon / mortise joints T1, angularly offset from the cutting teeth 23, 24, which do not protrude axially from the respective sleeves 270. The first of the cutting modules T1 is also coupled to the coupling portion 22 by a tenon / mortise joint 273.

[0100] Regarding the conformation of the cutting teeth 23, 24, referring to Figure 3:

[0101] - each cutting tooth on the right 23 and each cutting tooth on the left 24 have the same clearance angle Al between 6 and 20 degrees, and for example 15 degrees;

[0102] - 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;

[0103] - 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. In the examples 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.

[0104] Referring to Figure 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.

[0105] 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.

[0106] 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.

[0107] In the example of Figure 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.

[0108] In the example of Figure 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.

[0109] In the examples in Figures 5 and 6 where the opening angle A3 is 180 degrees, when one of the cutting teeth is active (i.e. it cuts 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.

[0110] In the example shown in Figures 3 and 4, where the opening angle A3 is 90 degrees, the configuration of the two cutting edges 230 and 240, positioned at 90° to each other and on the same cutting circle Cl, allows that when one of the cutting teeth is active (i.e., when it is notching the wood and forming a chip 100; the right-hand cutting tooth 23 in the example shown in Figure 3), the inactive cutting tooth, positioned at 90° and designed to cut in the opposite direction of rotation (the left-hand cutting tooth 24 in the example shown in Figure 3), simultaneously disengages from the cutting diameter. This disengagement of the inactive cutting tooth is caused by the cutting force from the torque of the motorized drive device 3, and thus does not 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 less than the cutting radius.

[0111] 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 Figure 1, a telescopic pole 51 is mounted on this housing 31, while in the version of Figure 2, a handling handle 52 is mounted on the housing 31.

[0112] Referring to Figure 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.

[0113] The alternating reversing mechanism of the direction of rotation 30 includes 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 arm 35, and this oscillating rocker arm 35 is coupled in rotation with the coupling portion 22 of the cutting cutter 2.

[0114] In a particular embodiment, the eccentric system 34 includes a toothed wheel 36 meshing with the drive shaft 33, either directly or via a reducer or multiplier. It is also possible to provide a gear reducer with a reduction ratio from 1 to 1 / 10.

[0115] The eccentric system 34 also includes a connecting rod 37 having a first end 371 articulated on the gear wheel 36 and a second end 372 articulated on the oscillating balance wheel 35. Thus, the drive shaft 33 rotates the gear wheel 36, and the connecting rod 37 moves back and forth so that its second end 372 causes the oscillating balance wheel 35 to oscillate, pivoting successively to the right and to the left. In the illustrated example, the oscillating balance wheel 35 completes a half-rotation of 90 degrees to the right as the connecting rod 37 moves down, and then a half-rotation of 90 degrees to the left as the connecting rod 37 moves up. Thus, the amplitude of the oscillations of the oscillating balance wheel 35 is 90 degrees, but it can be greater and, for example, be between 90 and 120 degrees.

[0116] 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 allows a multiplication ratio, for example, between 6 and 8, in order to allow the oscillating rocker arm 35 in its 90-degree (or even 120-degree) oscillation to obtain on the pinion 38, and therefore on the cutting cutter 2, an alternating rotation of 2 turns to the right and then 2 turns to the left.

[0117] According to an advantageous option, the motorized drive unit 3 includes a variable speed drive for adjusting the rotational speed of the motor shaft 33. For example, this 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 whose duration can be programmed by the operator, for example, from 0.3 to 1 second.

Claims

DEMANDS 1. Cutting apparatus (1) comprising: - 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); 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) having a right-hand cutting edge (230) oriented for cutting in a clockwise direction (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 cutting 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 (SI) with a first angular amplitude and counterclockwise (S2) with a second angular amplitude.

2. Cutting device (1) according to claim 1, in which 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 device (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 device (1) according to any one of the preceding claims, in which 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, in which 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 cutting tooth on the right (23) and at least one cutting tooth on the left (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 device (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 device (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 device (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, in which 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 device (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 reversal mechanism of the direction of rotation (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 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) in mesh 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 device (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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