Active and passive dual grass cutter overload release mechanism

Abstract

The application discloses a kind of active and passive dual grass cutter overload disengaging mechanism, it is related to the technical field of grass cutter, including tool seat and control rod, tool seat is used to drive motor output shaft and grass cutter transmission connection, and it can remove the transmission state of drive motor output shaft and grass cutter when grass cutter hits hard obstacle, the grass cutter of the present application adopts external sheet structure, the blade of two grass cutters is symmetrically arranged, and can cut tough weeds;One end of control rod is connected with the tool seat, and the other end is connected with servo motor, the servo motor can drive the control rod to drive the tool seat to move to set position, for changing the transmission state of drive motor output shaft and grass cutter.The present application can cut tough weeds, and when grass cutter hits hard obstacle, it can be disengaged from the transmission state of drive motor, to avoid damage to tool seat and drive motor etc..

Description

Technical Field

[0001] This invention relates to the field of lawnmower technology, and in particular to an overload release mechanism for a dual active and passive mowing blade. Background Technology

[0002] Electric lawnmowers operate in complex environments. Hard objects such as bricks and stones hidden in dense grass often collide with the mowing blades. When the blades rotate at high speed and suddenly strike obstacles exceeding the blades' cutting capacity, such as stones, concrete blocks, or steel bars, irreversible damage can occur to the blades, the blade holder, the output shaft, and even the motor at the rear. The shattered fragments can also cause injury to people in the vicinity.

[0003] Traditional soft-tipped lawnmowers (mowing ropes) can avoid damage to the blade holder from impacts with obstacles, but their cutting power is insufficient to handle dense and tough weeds; while centrifugal blades are prone to failure to launch properly, rendering them unusable. Therefore, there is an urgent need for a device that can cut dense and tough weeds while avoiding damage to the blade holder, motor, and other components from impacts with obstacles such as rocks. Summary of the Invention

[0004] The purpose of this invention is to provide an overload disengagement mechanism for a dual active and passive lawnmower blade to solve the problems existing in the prior art. This mechanism is capable of cutting tough weeds and disengaging from the drive motor when the lawnmower blade hits a hard obstacle, thus avoiding damage to the blade holder and drive motor.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] This invention provides an overload release mechanism for a dual active and passive lawnmower blade, comprising:

[0007] The blade holder is used to connect the output shaft of the drive motor and the grass cutter. It can also disengage the drive motor output shaft and the grass cutter when the grass cutter hits a hard obstacle. The present invention adopts an externally mounted blade-shaped grass cutter with two blades symmetrically arranged, which can cut tough weeds.

[0008] A control lever has one end connected to the blade holder and the other end connected to a servo motor. The servo motor can drive the control lever to move the blade holder to a set position, thereby changing the transmission state of the output shaft of the drive motor and the grass cutter.

[0009] Optionally, the knife seat comprises a knife seat sleeve, one end of the knife seat sleeve is open, the other end is internally provided with a wall, an outer gear disc is fixedly arranged on the wall, the end of the knife seat sleeve provided with the outer gear disc is provided with a through hole, the output shaft of the driving motor is drivingly connected with an adapter shaft, the adapter shaft is arranged in the through hole of the knife seat sleeve, and one end of the adapter shaft in the knife seat sleeve is fixedly provided with an inner gear disc, the inner gear disc and the outer gear disc can be drivingly connected in meshing mode; the outer wall of the open end of the knife seat sleeve is fixedly connected with the grass cutting knife; the inner gear disc and the outer gear disc are drivingly connected in meshing mode, so that the grass cutting knife is controlled to cut grass by the driving motor, when the grass cutting knife hits hard obstacles such as stones, the grass cutting knife and the outer gear disc fixedly arranged thereon stop instantaneously, and the inner gear disc continues to maintain a high-speed movement trend; when the torque transmitted by the engagement surface of the inner gear disc and the outer gear disc exceeds a set value, the outer gear disc and the knife seat sleeve are pushed to move towards the driving motor, the passive disengagement of the outer gear disc from the inner gear disc is realized, and the driving motor is prevented from being damaged.

[0010] Optionally, the open end of the knife seat sleeve is internally provided with an elastic member, the position of the elastic member can be adjusted along the axial direction of the knife seat sleeve, and one end of the elastic member is in abutment with the end face of the end of the inner gear disc away from the adapter shaft, so that the inner gear disc and the outer gear disc are provided with meshing pressure.

[0011] Optionally, the adjustment disc is further provided, the outer wall of the adjustment disc is provided with external threads, the inner wall of the knife seat sleeve is provided with internal threads, the adjustment disc is arranged in the knife seat sleeve and is in threaded connection with the knife seat sleeve, and the elastic member is located between the adjustment disc and the inner gear disc; a hexagonal hole is arranged at the central position of the adjustment disc, the adjustment disc can be rotated by an external adjustment rod or the like, the adjustment disc can be moved towards or away from the inner gear disc along the inner wall of the knife seat sleeve, the elastic member can be compressed, and the function of adjusting the passive disengagement torque can be realized.

[0012] Optionally, the elastic member is a spring.

[0013] Optionally, the outer wall of the end of the knife seat sleeve away from the grass cutting knife is annularly provided with a limiting groove, an axial limiting device is sleeved in the limiting groove, the axial limiting device can rotate relative to the knife seat sleeve, one end of the axial limiting device is fixedly connected with the control rod, the control rod can drive the axial limiting device to drive the knife seat sleeve to move synchronously in the axial direction; the axial limiting device does not rotate with the knife seat sleeve during the operation of the grass cutting knife, when the servo motor drives the control rod to move up and down, the axial limiting device can drive the knife seat sleeve to move up and down, and then the inner gear disc and the outer gear disc are disengaged or meshed, and the active control of the meshing state of the inner gear disc and the outer gear disc can be realized.

[0014] Optionally, the servo motor is arranged at the end of the driving motor away from the cutter sleeve, and the motor shaft of the servo motor is arranged perpendicularly to the output shaft of the driving motor; the motor shaft of the servo motor is fixedly connected with an eccentric wheel, the outer end surface of the eccentric wheel is movably connected with an L-shaped plate through an eccentric connecting rod, one end of the L-shaped plate is connected with the control rod, and the other end of the control rod is hingedly connected with the axial limiting device.

[0015] Optionally, the axial limiting device comprises two symmetrically arranged half circular rings, and the two ends of each half circular ring are fixedly provided with an extension rod; after the two half circular rings are abutted and clamped in the limiting groove, the two extension rods on the same side can abut; and the two extension rods on the same side are hingedly connected with one end of the control rod.

[0016] Optionally, the outer tooth disc and the inner tooth disc are both annularly provided with inclined teeth.

[0017] Optionally, the motor shaft of the servo motor is fixedly connected with the center of the eccentric wheel, and the eccentric connecting rod is fixedly arranged on the outer side end surface of the eccentric wheel; when the eccentric connecting rod is farthest away from the cutting blade in a straight line, the outer tooth disc and the inner tooth disc are disengaged from meshing transmission; when the eccentric connecting rod is closest to the cutting blade in a straight line, the outer tooth disc and the inner tooth disc are locked and always in a meshing state; and when the eccentric connecting rod is between the maximum and minimum straight-line distances from the cutting blade, the inner tooth disc and the outer tooth disc are in a free state, and the meshing state is passively adjusted according to whether the cutting blade hits a hard obstacle.

[0018] The present application has the following technical effects relative to the prior art:

[0019] In the present application, the cutter holder is connected with the output shaft of the driving motor and the cutting blade, the motor output shaft is connected with the inner tooth disc, the cutting blade is fixed with the outer tooth disc, the outer tooth disc is meshed with the inner tooth disc, and the meshing pressure is provided by the elastic member. The control rod is driven by the servo motor, and the meshing state of the inner tooth disc and the outer tooth disc is actively controlled and sensed by adjusting the state of the control rod. During the mowing operation, the control rod is in a free state. The motor output shaft transmits torque to the cutting blade through the inner and outer tooth discs for mowing operation, and when the cutting blade encounters a hard obstacle, the inner and outer tooth discs are disengaged, thereby passively releasing the meshing state, and damage to the blade and the driving motor is avoided. BRIEF DESCRIPTION OF DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings described in the following only constitute some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0021] Figure 1 It is the perspective view of the active and passive double grass cutter overload disengagement mechanism of the application;

[0022] Figure 2 It is the front view of the active and passive double grass cutter overload disengagement mechanism of the application;

[0023] Figure 3 It is the bottom view of the active and passive double grass cutter overload disengagement mechanism of the application;

[0024] Figure 4 It is the schematic diagram of the inner tooth disc, outer tooth disc and grass cutter after installation of the application;

[0025] Figure 5 It is the A-A section schematic diagram of the application; Figure 4

[0026] Figure 6 It is the schematic diagram of the knife seat sleeve of the application;

[0027] Figure 7 It is the schematic diagram of the internal structure of the knife seat sleeve of the application;

[0028] Figure 8 It is the schematic diagram of the inner tooth disc structure of the application;

[0029] Figure 9 It is the schematic diagram of the inner tooth disc, outer tooth disc and spring cooperation of the application.

[0030] In the figure: 1-knife seat sleeve, 2-control rod, 3-grass cutter, 4-driving motor, 5-servo motor, 6- eccentric wheel, 7-eccentric connecting rod, 8-inner tooth disc, 9-outer tooth disc, 10-spring, 11-adjusting disc, 12-adapter shaft, 13-limiting groove, 14-axial limiting device, 15-L-shaped plate. DETAILED DESCRIPTION

[0031] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0032] The purpose of the application is to provide an active and passive double grass cutter overload disengagement mechanism to solve the problems in the prior art, which can cut tough weeds and disengage from the driving motor when the grass cutter hits a hard obstacle, thereby avoiding damage to the knife seat and driving motor.

[0033] ​In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0034] The present application provides a kind of active and passive double grass cutter overload disengagement mechanism, refer to Figures 1-9 As shown, including tool holder and control rod 2, tool holder includes tool holder sleeve 1, tool holder sleeve 1 one end opening, the other end inside wall fixed ring is equipped with outer gear disc 9, tool holder sleeve 1 is equipped with outer gear disc 9 one end opening has through-hole, the output shaft of driving motor 4 is transmission connection with adapter shaft 12, one of the embodiments, adapter shaft 12 one end opening has adapter shaft hole, strip slot is opened in the inner wall of adapter shaft hole, the output shaft of driving motor 4 is fixedly inserted in adapter shaft hole, and the fixed insertion wedge in strip slot, realize the fixation of output shaft and adapter shaft 12;Adapter shaft 12 is inserted in the through-hole of tool holder sleeve 1, and the one end of adapter shaft 12 in tool holder sleeve 1 is fixedly provided with inner gear disc 8, inner gear disc 8 and outer gear disc 9 can be engaged transmission connection;The outer wall of the opening end of tool holder sleeve 1 is fixedly connected with grass cutter 3;The present application inner gear disc 8 and outer gear disc 9 are engaged transmission connection, so as to pass through driving motor 4 transmission torque control grass cutter 3 mowing, when hitting hard obstacles such as stone, grass cutter 3 and with its fixed outer gear disc 9 stops momentarily, inner gear disc 8 continues to maintain high-speed movement trend, the torque transmission of inner and outer gear disc joint surface exceeds the set value, outer gear disc 9 and tool holder sleeve 1 will be pushed to the direction of driving motor 4 movement, inner and outer gear disc slip, realize the passive overload disengagement of outer gear disc 9 and input end inner gear disc 8, so as to avoid damaging driving motor 4.

[0035] In order to make the present application inner gear disc 8 and outer gear disc 9 can be normal engagement transmission, and then drive grass cutter 3 to work, therefore need to provide a meshing pressure for inner gear disc 8 and outer gear disc 9, the present application adopts the mode of fixing a spring 10 on the inner wall of the opening end of tool holder sleeve 1 to realize this function, one end of spring 10 abuts with the end face of inner gear disc 8, the other end is fixedly connected with tool holder sleeve 1, and then provides the meshing force for inner gear disc 8 and outer gear disc 9, the position of spring 10 can be adjusted along the axis direction of tool holder sleeve 1, so as to change the size of meshing force, when spring 10 moves outward and is fixed, the spring force of spring 10 to inner gear disc 8 is small, the meshing force of inner gear disc 8 and outer gear disc 9 is small, which is suitable for cutting soft grass, when hard obstacles are encountered, grass cutter 3 cannot cut smoothly, the load of driving motor 4 exceeds the limit value, inner gear disc 8 and outer gear disc 9 can timely disengage from the meshing state, play a protective role.When spring 10 moves close to inner gear disc 8 and is fixed, the spring force of spring 10 to inner gear disc 8 is large, so that the torque of disengagement of inner gear disc 8 and outer gear disc 9 is larger, which is suitable for cutting weeds with toughness, and inner gear disc 8 and outer gear disc 9 are not disengaged during cutting weeds with toughness, when hard obstacles such as stone are encountered, inner gear disc 8 and outer gear disc 9 are passively disengaged, play a protective role.

[0036] The outer tooth disc 9 and the inner tooth disc 8 are both provided with bevel gears, and the two are connected through the bevel gears, one end surface of the bevel gears is a bevel surface, and the output torque T satisfies the condition

[0037]

[0038] At this time, the slip requirement is met, the inner tooth disc 8 and the outer tooth disc 9 are disengaged, the driving motor 4 drives the inner tooth disc 8 to continue to rotate, and the outer tooth disc 9, the cutter seat sleeve 1 and the mower blade 3 stop running, thereby playing a protection role. Wherein, R is the radius of the inner tooth disc 8 or the outer tooth disc 9, θ is the bevel angle of the bevel gear, F is the spring 10 pressure, and μ is the friction coefficient.

[0039] In a preferred embodiment, one end of the bevel gear of the outer tooth disc 9 and the inner tooth disc 8 of the application is a bevel structure, and the other end surface is a vertical cross-section structure. Whether the control rod 2 is in the free or locked position, the driving motor 4 can be reversely rotated to realize braking, and the mower blade 3 will not be disengaged, thereby ensuring reliable braking in any case.

[0040] In order to more flexibly adjust the spring 10 pressure, in a specific embodiment of the application, an adjusting disc 11 is specially designed. The main body of the adjusting disc 11 is a disc structure with a hexagonal hole in the center. A vertical flange is arranged around the edge of the disc. An outer thread is arranged on the outer wall of the vertical flange. An inner thread is arranged on the inner wall of the cutter seat sleeve 1. The adjusting disc 11 is placed into the cutter seat sleeve 1 from the opening end. The outer thread of the adjusting disc 11 is threadedly connected with the inner thread of the cutter seat sleeve 1. The spring 10 is located between the adjusting disc 11 and the inner tooth disc 8. The adjusting disc 11 can be rotated by an adjusting rod or an adjusting wrench inserted into the hexagonal hole, so that the adjusting disc 11 moves towards or away from the inner tooth disc 8 along the inner wall of the cutter seat sleeve 1, the compression of the spring 10 is realized, the spring 10 pressure is changed, and the function of adjusting the passive disengagement torque is realized.

[0041] In addition to the passive disengagement of the inner tooth disc 8 and the outer tooth disc 9 when the mower blade 3 encounters an obstacle, the application can also realize active overload disengagement or locking of the engagement of the inner tooth disc 8 and the outer tooth disc 9. In order to realize this function, a limiting groove 13 is arranged around the outer wall of the cutter seat sleeve 1 away from the mower blade 3. An axial limiting device 14 is sleeved in the limiting groove 13. The axial limiting device 14 can rotate relative to the cutter seat sleeve 1. The axial limiting device 14 is fixedly connected with one end of the control rod 2. The control rod 2 can drive the axial limiting device 14 to drive the cutter seat sleeve 1 to move synchronously in the axial direction. The axial limiting device 14 does not rotate with the cutter seat sleeve 1 when the mower blade 3 is working. When the servo motor 5 drives the control rod 2 to move up and down, the axial limiting device 14 can drive the cutter seat sleeve 1 to move up and down, thereby disengaging or engaging the inner tooth disc 8 and the outer tooth disc 9, and realizing active control of the engagement state of the inner tooth disc 8 and the outer tooth disc 9.

[0042] The setting form of the control rod 2 and the servo motor 5 is not specifically limited, and a cylinder structure can also be arranged at the other end of the control rod 2, the cylinder rod is arranged in parallel with the output shaft of the driving motor 4, the control rod 2 is pulled up and down by the cylinder, and the control of the up and down movement of the control rod 2 and the cutter sleeve 1 can also be realized, and a displacement sensor is arranged on the cylinder, and the position of the cutter sleeve 1 can be sensed. In order to control the inner tooth disc 8 and the outer tooth disc 9 more accurately, in a preferred embodiment, the servo motor 5 is arranged at the end of the driving motor 4 away from the cutter sleeve 1, and the motor shaft of the servo motor 5 is arranged in perpendicular to the output shaft of the driving motor 4; the motor shaft of the servo motor 5 is fixedly connected with the eccentric wheel 6, the motor shaft of the servo motor 5 is fixedly connected with the center of the eccentric wheel 6, the eccentric wheel 6 is fixedly provided with the eccentric connecting rod 7 on the outer end surface, the outer end surface of the eccentric wheel 6 is movably connected with one end surface of the L-shaped plate 15 through the eccentric connecting rod 7, the other end surface of the L-shaped plate 15 is movably connected with one end of the control rod 2, and the other end of the control rod 2 is hingedly connected with the axial limiting device 14. In this embodiment, in a virtual coordinate axis established with the plane where the eccentric wheel 6 is located, the position where the eccentric connecting rod 7 is located at the lowest end is 270°, the position where the eccentric connecting rod 7 is located at the highest end is 90°, and the positions where the eccentric connecting rod 7 is located at the horizontal two ends are respectively 180° and 0°. When the eccentric connecting rod 7 is located at the position of 270°, the control rod 2 is located at the lowest end, the inner tooth disc 8 and the outer tooth disc 9 are locked, and are always in the meshing state, the outer tooth disc 9 is fixed at the position combined with the inner tooth disc 8 by the control rod 2, the forced power output of the system can be realized, so as to meet the operation requirements in special conditions (such as shrubs, reeds and the like), when the servo motor 5 controls the rotation of the eccentric wheel 6, the control rod 2 connected with the eccentric connecting rod 7 is locked at the upper stop point when the eccentric connecting rod 7 is located at the position of 90°, at this time, the cutter sleeve 1 is raised, the lower tooth disc and the upper tooth disc are in the disengaged state, the driving motor 4 cannot drive the mower blade 3 to work, and the outer tooth disc 9 is lifted to the disengaged position by the control rod 2, so that the active disengagement output can be realized, and the motor starting under the condition of large load is facilitated. In this way, the meshing state of the inner tooth disc 8 and the outer tooth disc 9 can be actively adjusted.

[0043] When the servo motor 5 is not locked and the eccentric wheel 6 is freely rotated between 270° and 90°, the inner tooth disc 8 and the outer tooth disc 9 are in the free state. During the mowing operation, the control rod 2 is in the free state, the output shaft of the driving motor 4 transmits the torque to the mower blade 3 through the inner and outer tooth discs 9 to perform the mowing operation, at this time, whether the obstacle is encountered, the meshing state of the inner tooth disc 8 and the outer tooth disc 9 is passively controlled. When the mower blade 3 suddenly hits the obstacle (such as a stone) during high-speed rotation, the mower blade 3 and the outer tooth disc 9 fixed therewith are instantaneously stopped. The inner tooth disc 8 continues to maintain the high-speed movement trend. When the torque transmitted through the inner and outer tooth disc 9 interfaces exceeds the T value in the above formula, the outer tooth disc 9 will be pushed to move in the direction of the driving motor 4, and the disengagement with the input end inner tooth disc 8 is realized.

[0044] The application further has a sensing device, an angle sensor is arranged on the eccentric wheel 6, the engaging state of the inner tooth disc 8 and the outer tooth disc 9 is perceived by monitoring the position of the eccentric wheel 6, after the disengagement occurs, the control rod 2 moves together with the outer tooth disc 9, pushes the eccentric wheel 6 to rotate from 270o to 90o, the disengagement state can be known by the angle position of the eccentric wheel 6. At the same time, the characteristic current change of the load of the driving motor 4 occurs, that is, the current appears a characteristic fluctuation with a frequency f of

[0045] f=N*n / 60, the second feedback is given to the system, and the disengagement state of the inner tooth disc and the outer tooth disc is further determined, wherein N is the real-time rotating speed of the driving motor, and n is the tooth number of the inner tooth disc or the outer tooth disc, and the tooth numbers of the inner tooth disc and the outer tooth disc are equal. When the inner tooth disc and the outer tooth disc are engaged, the current is uniform or consistent with the load change. When the inner tooth disc and the outer tooth disc are disengaged (the inner tooth disc and the outer tooth disc slip), the load current will fluctuate with the characteristic frequency due to the jumping of the inner tooth disc teeth, the driving motor is provided with a sensing device and a controller, and the fluctuation can be captured by the driving motor controller, so that the system obtains the feedback and knows that the inner tooth disc and the outer tooth disc are disengaged.

[0046] In another embodiment, in order to adjust the tool holder sleeve 1 more stably, the axial limiting device 14 is designed as two symmetrical half circular rings, the two ends of the half circular rings are fixedly provided with extension rods, after the two half circular rings are abutted and clamped in the limiting groove 13, the two extension rods on the same side can abut; the two extension rods on the same side are hingedly connected with one end of the control rod 2, the two control rods 2 are symmetrically arranged and can synchronously adjust the tool holder sleeve 1.

[0047] The principle and implementation mode of the application are described by using specific examples in the application, and the above embodiment is only used to help understand the method and core idea of the application; meanwhile, according to the idea of the application, the specific implementation mode and application range can be changed by the person skilled in the art. In conclusion, the content of the specification should not be understood as the limitation of the application.

Claims

1. A dual-mode (active and passive) lawnmower overload release mechanism, characterized in that, include: The blade holder is used to connect the output shaft of the drive motor and the lawn mower, and it can disengage the drive motor output shaft and the lawn mower when the lawn mower hits a hard obstacle. A control lever, one end of which is connected to the blade holder and the other end of which is connected to a servo motor, the servo motor can drive the control lever to move the blade holder to a set position, thereby changing the transmission state of the output shaft of the drive motor and the grass cutter; The blade holder includes a blade holder sleeve, one end of which is open, and an external toothed disc is fixedly ringed on the inner wall of the other end. A through hole is formed at the end of the blade holder sleeve with the external toothed disc. An adapter shaft is connected to the output shaft of the drive motor. The adapter shaft passes through the through hole of the blade holder sleeve, and an internal toothed disc is fixedly mounted at the end of the adapter shaft located inside the blade holder sleeve. The internal and external toothed discs are capable of meshing and transmission. The grass-cutting blade is fixedly connected to the outer wall of the open end of the blade holder sleeve. The servo motor's motor shaft is fixedly connected to an eccentric wheel, and the outer end face of the eccentric wheel is movably connected to an L-shaped plate via an eccentric connecting rod. The servo motor's motor shaft is fixedly connected to the center of the eccentric wheel, and the eccentric connecting rod is fixedly mounted on the outer end face of the eccentric wheel. When the straight-line distance between the eccentric connecting rod and the mower blade is at its maximum, the outer and inner sprockets are disengaged and there is no meshing transmission. When the straight-line distance between the eccentric connecting rod and the mower blade is at its minimum, the outer and inner sprockets are locked and always in a meshing state. When the straight-line distance between the eccentric connecting rod and the mower blade is between the maximum and minimum ends, the inner and outer sprockets are in a free state, and the meshing state is passively adjusted according to whether the mower blade hits a hard obstacle.

2. The active and passive dual-mode lawnmower overload release mechanism according to claim 1, characterized in that, An elastic element is fixedly provided on the inner wall of the open end of the tool holder sleeve. The position of the elastic element can be adjusted along the axial direction of the tool holder sleeve, and one end of the elastic element abuts against the end face of the inner gear plate away from the adapter shaft.

3. The active and passive dual-mode lawnmower overload release mechanism according to claim 2, characterized in that, It also includes an adjusting disc, which has an external thread on its outer side wall and an internal thread on its inner side wall. The adjusting disc is located inside the tool holder sleeve and is threadedly connected to the tool holder sleeve. The elastic element is located between the adjusting disc and the internal toothed disc.

4. The active and passive dual-mode lawnmower overload release mechanism according to claim 2, characterized in that, The elastic element is a spring.

5. The active and passive dual-mode lawnmower overload release mechanism according to claim 1, characterized in that, The outer wall of the blade holder sleeve away from the grass cutter is provided with a limiting groove. An axial limiting device is sleeved in the limiting groove. The axial limiting device can rotate relative to the blade holder sleeve. The axial limiting device is fixedly connected to one end of the control rod. The control rod can drive the axial limiting device to move the blade holder sleeve synchronously along the axial direction.

6. The active and passive dual-mode lawnmower overload release mechanism according to claim 5, characterized in that, The servo motor is located at the end of the drive motor away from the tool holder sleeve, and the motor shaft of the servo motor is arranged perpendicular to the output shaft of the drive motor; the L-shaped plate is connected to one end of the control rod, and the other end of the control rod is hinged to the axial limiting device.

7. The active and passive dual-mode lawnmower overload release mechanism according to claim 5, characterized in that, The axial limiting device includes two symmetrically arranged semicircular rings. Extension rods are fixed at both ends of the semicircular rings. After the two semicircular rings are engaged and locked in the limiting groove, the two extension rods on the same side can abut against each other. The two extension rods on the same side are hinged to one end of the control rod.

8. The active and passive dual-mode lawnmower overload release mechanism according to claim 1, characterized in that, Both the external and internal toothed discs are provided with beveled teeth.

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