Mowing machine

Abstract

To provide a control means which does not add a vibration sensor, does not limit the kind of a prime mover, automatically detects an abnormal vibration state generated in a machine body by the defect or the like of a cutting blade, and stops the cutting blade.SOLUTION: In a radio-controlled mower including a reaping device (4) provided with a rotary blade (3) on a front-rear central belly portion (2) of a machine body (1), a motor (5) for rotationally driving the rotary blade (3), a reaping blade clutch (6) capable of turning on and off transmission to the rotary blade (3), and an acceleration sensor (7) for detecting front-rear and left-right inclinations of the machine body (1), control is performed to stop rotation of the rotary blade (3) when the acceleration sensor (7) detects an abnormal vibration state of the machine body (1).SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to the control of a radio-controlled grass cutter for cutting grass, weeds, etc. [Background technology]

[0002] A remote-controlled mower is known from the past, as disclosed in Patent Document 1. This remote-controlled mower allows the operator to remotely operate the mower from a safe location, and is said to eliminate the need for the operator to actually stand on the slope while working, eliminating the risk of tipping over or falling off the slope, and eliminating the risk of the rotating mower blade hitting pebbles or other foreign objects that could hit the operator's eyes or body.

[0003] Furthermore, as disclosed in Patent Document 2 below, a lawnmower equipped with a blade abnormality detection unit is known. This lawnmower is said to automatically detect and alert those around it if an abnormality such as a chipped blade occurs in the blade, or to automatically stop the blade motor, thereby increasing the durability of the lawnmower. Here, when the blade, which rotates at high speed due to the blade motor, breaks, vibrations are generated due to imbalance in the rotation. Therefore, methods using a vibration sensor for the blade abnormality detection unit and techniques for detecting vibrations based on fluctuations in the current in the blade motor have been disclosed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2011-142900 [Patent Document 2] Patent Publication No. 2016-158594 Summary of the Invention [Problem to be solved by the invention]

[0005] In the case of remotely controlled brush cutters, such as those described in Patent Document 1, the operator must operate the mower from a distance, making it difficult to detect obstacles such as stones in the work area. This increases the likelihood of the blade coming into contact with an obstacle and breaking off, compared to when the operator is close to the mower. Breaking off the blade, which rotates at high speed, can cause imbalance and vibration, potentially damaging components of the mower or causing solder cracks in electronic components, leading to malfunctions. Furthermore, operators who are far from the mower may have difficulty noticing abnormal vibrations, potentially delaying the decision to stop the rotation of the blade.

[0006] However, when the lawnmower configuration described in Patent Document 2 is applied to a grass mower, there are inconveniences such as the need to install a new vibration sensor and the method of driving the cutting blade being limited to a motor.In particular, with regard to the method of driving the cutting blade, unlike lawnmowers, engine-powered grass mowers are the mainstream in terms of output, durability, etc., so it is desirable that the abnormality detection means can also be applied to engine-powered models.

[0007] Based on the above, the problem that the present invention aims to solve is to provide a control means that does not require the installation of a new vibration sensor, can use any type of prime mover to drive the blade, and automatically detects abnormal vibration conditions caused by damage to the blade, etc., and stops the blade. [Means for solving the problem]

[0008] The invention described in claim 1 is a radio-controlled grass cutter equipped with a cutting device 4 having a rotary rotary blade 3 mounted on the front-to-rear central abdomen 2 of the machine body 1, a prime mover 5 that drives the rotary rotary blade 3 to rotate, a cutting blade clutch 6 that transmits power to the rotary rotary blade 3 and enables cutting, and an acceleration sensor 7 that detects the tilt of the machine body 1 in the front-to-rear and left-to-right directions, and is configured to control the rotation of the rotary rotary blade 3 to stop when the acceleration sensor 7 detects an abnormal vibration state of the machine body 1.

[0009] Furthermore, when the acceleration sensor 7 detects an abnormal vibration state, the motor 5 is stopped, or the blade clutch 6 that turns on and off the rotary drive to the rotary blade 3 is turned off, or both are performed. [Effects of the Invention]

[0010] According to the invention of claim 1, in a wirelessly controlled brush cutter equipped with a harvesting device 4 equipped with a rotary rotary blade 3 on a central abdominal portion 2 in the front and rear of the machine body 1, a prime mover 5 that rotates and drives the rotary rotary blade 3, a cutting blade clutch 6 that transmits power to the rotary rotary blade 3 and enables cutting, and an acceleration sensor 7 that detects the tilt of the machine body 1 in the front, rear, and left and right directions, the machine body is configured so that if the acceleration sensor 7 detects an abnormal vibration state of the machine body 1, it will perform control to stop the rotation of the rotary rotary blade 3, so that the acceleration sensor 7 that has conventionally been installed on the machine body 1 can detect abnormal vibration and automatically stop the rotation of the rotary rotary blade 3 without providing a separate vibration sensor. In addition, the type of prime mover 5 is not limited and it could be an engine, for example.

[0011] According to the invention of claim 2, when the acceleration sensor 7 detects an abnormal vibration state, the engine 5 is stopped, or the cutting blade clutch 6, which turns on and off the rotational drive to the rotary blade 3, is disengaged, or both are performed. Therefore, for example, if an engine is used for the engine 5, stopping the engine makes it easier for the operator to recognize the occurrence of abnormal vibration. Alternatively, in a brush cutter that is driven by the engine 5, not stopping the engine allows the machine body 1 to quickly evacuate after the occurrence of abnormal vibration. Alternatively, by performing both of these controls, safety can be further improved. [Brief explanation of the drawings]

[0012] [Figure 1] Left side view of a radio-controlled brush cutter. [Figure 2] FIG. 10 is a side view showing the mowing deck mounting configuration using parallel links. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. 4 is a plan view showing a belt transmission mechanism of the blade shaft. [Figure 6] FIG. [Figure 7] FIG. 4 is a partial plan view showing the mechanism of the blade clutch. [Figure 8] FIG. 1 is a block diagram of a radio-controlled brush cutter showing the control system. [Figure 9] FIG. 1 is a block diagram showing a portion of an abnormal vibration detection system. [Figure 10] 1 is a flowchart of an abnormal vibration detection system. DETAILED DESCRIPTION OF THE INVENTION

[0013] A wirelessly controlled brush cutter according to one embodiment of the present invention will be described with reference to the drawings. This wirelessly controlled brush cutter is equipped with a pair of left and right crawlers 9 mounted on a frame 8 forming a machine body 1. A travel motor M for driving the travel crawlers 9, a transmission case 10, and a drive sprocket 64 are mounted at the rear end of the frame 8. A control box 12 containing a control unit 11 for controlling the travel and mowing of the machine body 1 is attached to the frame 8 above the travel motor M. A reaping device 4 is mounted in the front-rear center 2 between the left and right crawlers 9, approximately in the center of the machine body 1 from front to rear. The reaping device 4 is suspended via a parallel link mechanism 14 at four points on the front and rear sides by a lifting cylinder 13, allowing for adjustable elevation. An engine base 15 is mounted above the reaping device 4. An engine E is mounted on the front of the upper surface of the engine base 15. An alternator 16, a fuel tank 17, a traction battery 18, and other components are located behind the engine E. A guard pipe 19 is provided above the frame 8, connecting the front and rear ends of the frame 8 in an arch-like shape, and a resin cover 20 is attached to the guard pipe 19 to cover the control box 12, fuel tank 17, etc. The machine 1 is wirelessly controlled using a proportional controller 21, and various lever operations enable the machine 1 to travel and turn, start and stop the engine E, and engage and disengage the blade clutch 6. The controller 21 is also equipped with a monitor 22, which can display information about the machine 1, etc.

[0014] The reaping device 4 has a vertical blade shaft 24 rotatably mounted in the center of the reaping deck 23, a mowing blade 25 attached to the lower end of the blade shaft 24, and mowing blades 26 pivotally supported at both ends of the mowing blade 25. A mowing blade pulley 27 having a V-belt groove is attached to the upper end of the blade shaft 24 on the upper side of the reaping deck 23. Also, a counter shaft 28 is erected in the vertical direction above the reaping deck 23 at a position rearward of the blade shaft 24, and a counter pulley 29 having upper and lower two-stage V-belt grooves is rotatably attached to the counter shaft 28.

[0015] The engine E has a drive shaft 30 that protrudes vertically below the engine base 15, and an engine pulley 31 with two V-belt grooves, one above the other, is attached to the drive shaft 30. The alternator 16, located behind the engine E, also has a generator shaft 32 that protrudes vertically below the engine base 15, and a generator pulley 33 with a V-belt groove is attached to the generator shaft 32. For power generation transmission, a generator belt 34 is looped between the upper V-belt groove of the engine pulley 31 and the V-belt groove of the generator pulley 33, providing a constant transmission tension. When the engine E is started, the alternator 16 rotates to generate electricity and charge the traction battery 18. For reaping transmission, a counter belt 35 is looped between the lower V-belt groove of the engine pulley 31 and the upper V-belt groove of the counter pulley 29, providing a constant transmission tension. When the engine E is started, the counter pulley 29 rotates. A cutting belt 36 is stretched between the V-belt groove at the lower stage of the counter pulley 29 and the cutting blade pulley 27, and a tension pulley 37 is provided on the rotating outer periphery of the cutting belt 36 to tension and relax the cutting belt 36, thereby enabling power transmission from the counter shaft 28 to the blade shaft 24 to be switched on and off.

[0016] The cutting blade clutch 6 has a pivot shaft 38 provided on the upper side of the cutting deck 23 and to the left rear of the counter shaft 28 in the vertical direction, and a clutch arm 39 that pivotally supports a tension pulley 37 is pivotally attached to the pivot shaft 38. One end of a clutch wire 40 is connected to the clutch arm 39, and the other end is connected to an operating arm 41. The operating arm 41 is rotatably attached around an arm shaft 42 provided on the frame 8 and is connected to a cutting cylinder 43 that is electrically extended and retracted. In addition, a brake arm shaft 44 is provided on the upper side of the cutting deck 23 and to the rear of the cutting blade pulley 27 in the vertical direction, and a brake arm 46 equipped with a brake shoe 45 that fits into and slides in the V-belt groove of the cutting blade pulley 27 to brake the rotation of the blade shaft 24 is pivotally attached to the brake arm 44. One end of a brake wire 47 is connected to the brake arm 46, and the other end is connected to the operating arm 41.

[0017] When the cutting blade clutch 6 is engaged, the cutting cylinder 43 is pushed out, causing the operating arm 41 to rotate from the off-cut position b to the on-cut position a and pull the clutch wire 40. Pulled by the clutch wire 40, the clutch arm 39 rotates about the pivot shaft 38 against the elastic force of the spring 48, causing the tension pulley 37 to tension the cutting belt 36 and switch the cutting transmission into the engaged state. Further, the pushing operation of the cutting cylinder 43 causes the operating arm 41 to rotate from the brake-on position f to the brake-off position e and pull the brake wire 47. Pulled by the brake wire 47, the brake arm 46 rotates about the brake arm shaft 44 against the elastic force of the spring 49, causing the brake shoe 45, which is fitted and pressed against the V-belt groove of the cutting blade pulley 27, to move outward, releasing the braking force.

[0018] Furthermore, when the cutting blade clutch 6 is switched off, the cutting cylinder 43 is contracted, causing the operating arm 41 to rotate from the cutting-on position a to the cutting-off position b, and also from the brake-off position e to the brake-on position f. The elastic force of the spring 48 causes the clutch arm 39 to rotate about the pivot shaft 38, and the tension pulley 37 moves away from the cutting belt 36, becoming relaxed and disengaging power. The elastic force of the spring 49 also causes the brake arm 46 to rotate about the brake arm shaft 44, which engages and presses the brake shoe 45 into the V-belt groove of the cutting blade pulley 27, applying the brake and braking the blade shaft 24. As described above, the cutting belt 36 smoothly switches on and off the cutting power transmission.

[0019] The engine base 15 is equipped with rolling shafts 50 at the center of the left-right width at the front and rear ends. The rolling shafts 50 are fitted and supported on support metals 52 provided at the left-right center positions of horizontal rails 51 at the front and rear of the frame 8, allowing the engine base 15 to rotate freely left and right. Furthermore, a trapezoidal bracket 53 is formed at the rear end of the engine base 15, and a tilt cylinder 54 is attached between the bracket 53 and the frame 8. The tilt cylinder 54 extends and retracts based on the forward / backward / left-right tilt angle of the aircraft body 1, allowing the engine base 15 to rotate left and right.

[0020] The control box 12 is a housing that houses the control unit 11, which is composed of an arithmetic unit 55, a signal processing unit 56, a storage device 57, a travel control device 58, an acceleration sensor 7, a communication device 59, etc. The control unit 11 is electrically connected to the engine E, the cutting cylinder 43, the driving battery 18, the driving motor M, etc., so that it can control the travel of the machine 1, the start and stop of the engine E, and the engagement and disengagement of the cutting blade clutch 6. In addition, an external terminal communication device 60 that is electrically connected to the control unit 11 is attached to the top surface of the control box 12. The external terminal communication device 60 can wirelessly send and receive signals to and from an external terminal 61 such as a smartphone. For example, it is possible to display malfunction information about the machine 1 on the screen of the external terminal 61 and control the machine 1 by operating the external terminal 61.

[0021] The arithmetic device 55 acquires information from the storage device 57, the travel control device 58, and the acceleration sensor 7 via the signal processing device 56, and performs processing to calculate the state of the machine 1 and determine abnormalities. The signal processing device 56 controls the calculations for the arithmetic device 55, controls the input and output of information to the arithmetic device 55, the storage device 57, and the communication device 59, and controls input from the acceleration sensor 7. Here, the arithmetic device 55 and the signal processing device 56 may be integrated into one device. The storage device 57 stores control programs for the travel of the machine 1, the reaping transmission, etc. It can also store information from the arithmetic device 55 and the acceleration sensor 7. The travel control device 58 drives the travel motor M by commands sent via the arithmetic device 55 based on input signals from the operation of the controller 21 or the external terminal 61.

[0022] 9 is a partial block diagram of a system for detecting abnormal vibrations in this embodiment. The acceleration sensor 7 outputs accelerations in the front-to-back, left-to-right, and up-to-down directions of the aircraft 1. In the figure, X indicates the front-to-back direction of the aircraft 1, Y indicates the left-to-right direction, and Z indicates the up-to-down direction. X1 and X2 indicate the raw data and noise-removed data in the front-to-back direction of the aircraft 1, Y1 and Y2 indicate the raw data and noise-removed data in the left-to-right direction of the aircraft 1, and Z1 and Z2 indicate the raw data and noise-removed data in the up-to-down direction of the aircraft 1.

[0023] The raw data in each direction output from the acceleration sensor 7 is averaged by the computing device 55, and the state of the machine body 1 is detected based on the averaged data. Specifically, the machine body 1's forward / backward and left / right tilt is detected based on the acceleration in the forward / backward and left / right directions, and whether the machine body 1 is inverted is detected based on the acceleration in the up / down direction. Based on the detected tilt of the machine body 1, the tilting cylinder 54 is extended and retracted to rotate the engine base 15 left and right, thereby maintaining the engine E's mounting position vertically or below the allowable tilt angle of the engine E when mowing on slopes. In particular, this embodiment uses a wet sump engine for the engine E. Wet sump engines use a pump to suction oil collected in an oil pan at the bottom of the engine for internal lubrication. However, if the engine tilts, the oil becomes unevenly distributed and cannot be suctioned, which can lead to engine seizure. Therefore, although the maximum continuous operating angle is typically 20 to 25 degrees, the above-described configuration allows even a wet sump engine to mow on slopes of 30 degrees or more. Furthermore, by transmitting the detection result of the tilt of the machine body 1 to the controller 21 or the external terminal 61 and displaying it on the screen of the monitor 22 or the external terminal 61, the operator can perform the mowing work while checking the tilt of the machine body 1 at hand. Furthermore, the computing device 55 may be configured to notify the operator when it detects a preset angle. For example, if the travel limit angle of the machine body 1 is 45 degrees, and the machine body 1 tilts to 45 degrees or to 40 degrees, which is close to the travel limit angle, the machine body 1 may be deemed to be in danger of tipping over, and the traveling of the machine body 1 may be temporarily stopped, or the operator may be notified by the LED lamp 62 or buzzer 63 provided on the machine body 1, or by a display on the screen of the monitor 22 or the external terminal 61. With these configurations, mowing work on slopes using remote control can be performed safely.

[0024] Meanwhile, the processor 55 determines whether abnormal vibration is occurring in the machine body 1 based on noise-removed data obtained by filtering raw data output from the acceleration sensor 7. In this embodiment, if the processor 55 determines abnormal vibration in the machine body 1, it controls the engine E to stop, which also stops the blade shaft 24. Furthermore, the abnormality is notified to the operator by an LED lamp 62 or a buzzer 63 provided on the machine body 1, or by a display on the screen of the monitor 22 or external terminal 61. In this embodiment, the driving of the engine E charges the traveling battery 18 via the alternator 16. Even if the engine E stops, power is supplied from the traveling battery 18 to rotate the traveling motor M forward and reverse, driving the traveling crawler 9, thereby enabling electric travel. Therefore, the machine body 1 can be temporarily evacuated without restarting the engine E, and after inspection or repair, grass cutting work can be resumed.

[0025] Alternatively, when the computing device 55 determines abnormal vibration in the machine body 1, the computing device 55 may control the engine E to be stopped and the blade clutch 6 to be disengaged, thereby stopping the rotation of the blade shaft 24. In this case, the cutting cylinder 43 is contracted, and the brake shoe 45 is engaged and pressed against the V-belt groove of the cutting blade pulley 27, thereby applying the brake, thereby quickly stopping the blade shaft 24. Furthermore, in a brush cutter that can be driven by the engine E, there is no need to restart the engine E when the machine body 1 is evacuated for inspection or repair. Alternatively, when the computing device 55 determines abnormal vibration in the machine body 1, the computing device 55 may control the engine E to be stopped and the blade clutch 6 to be disengaged. In this case, since the engine E is stopped, the buzzer 63 is more audible to the operator, helping the operator to recognize the occurrence of an abnormality. In addition, the blade shaft 24 can be quickly stopped, minimizing damage to various parts caused by abnormal vibration.

[0026] Furthermore, by using averaged data to detect the tilt angle of the vehicle 1 and data that has had noise removed by a filter circuit to detect abnormalities, both tilt angle detection and abnormal vibration detection can be performed with high accuracy. Using averaged data alone makes it difficult to distinguish between an increase in tilt angle and the occurrence of abnormal vibration when attempting to detect abnormal vibration, and there is a risk of mistaking the tilt angle for an abnormal vibration even though abnormal vibration is occurring. On the other hand, using data that has had noise removed by a filter circuit to detect the tilt angle of the vehicle 1 is inaccurate, resulting in problems such as inappropriate rotation control of the engine base 15 or a tilt angle that is significantly different from the actual value displayed on the monitor 22, etc.

[0027] FIG. 10 is a flowchart showing the abnormality detection process in this embodiment. In step ST1, which is the starting point of this flowchart, the cutting blade clutch 6 is engaged. In step ST2, the arithmetic unit 55 acquires raw data output from the acceleration sensor 7 and noise-removed data that has passed through a filter circuit. In step ST3, the arithmetic unit 55 averages the raw data. In step ST4, the arithmetic unit 55 calculates the inclination of the machine body 1 using the averaged data. If in step ST5 the inclination of the machine body 1 is less than the travel limit angle, it is determined that travel can continue, and the process returns to step ST2. If the inclination of the machine body 1 is greater than the travel limit angle, in step ST6 it is determined whether the noise-removed data is within a predetermined range between a positive threshold UL and a negative threshold LL. If the noise-removed data is detected within the range between the positive threshold UL and the negative threshold LL, it is determined that abnormal vibration is not occurring and that the inclination of the machine body 1 has actually exceeded the travel limit angle. In step ST7, travel is temporarily stopped, and then in step ST8 the operator is notified of the abnormal inclination angle. On the other hand, if noise-removed data is detected outside the range between the positive threshold UL and the negative threshold LL in step ST6, it is determined that abnormal vibration is occurring, engine E is stopped in step ST9, and then the operator is notified of the occurrence of abnormal vibration in step ST10.

[0028] The positive threshold UL and negative threshold LL used to determine the noise-removed data may be set to a level that allows for detection of abnormal vibrations that may occur in the brush cutter. For example, data output from the acceleration sensor 7 is collected while mowing in a location where normal mowing operations are performed, and then data output from the acceleration sensor 7 when abnormal vibrations are occurring in the mower body 1 is collected. The positive threshold UL and negative threshold LL are then set to values ​​that are a predetermined amount larger in absolute value than the peak value of the data output during normal mowing operations and that allow for the determination of abnormal vibrations. Furthermore, the accuracy of abnormal vibration detection can be improved by controlling the system so that abnormal vibrations are determined when noise-removed data is detected outside the range of the positive threshold UL or negative threshold LL a predetermined number of times or more within a predetermined time. Additionally, the data monitoring period used for determination is not limited to a predetermined time, and may be replaced by frequency. [Explanation of symbols]

[0029] 1 aircraft 2 Anteroposterior central abdomen 3 Rotary blade 4 Reaping device 5. Prime Mover 6 Blade clutch 7 Acceleration Sensor

Claims

1. A wirelessly controlled grass trimmer comprising a cutting device (4) with a rotary blade (3) mounted on the front-to-rear central abdomen (2) of a machine body (1), a prime mover (5) that drives the rotary blade (3) to rotate, a cutting blade clutch (6) that transmits power to the rotary blade (3) and enables cutting, and an acceleration sensor (7) that detects the tilt of the machine body (1) in the front, rear, left and right directions, characterized in that the acceleration sensor (7) controls the rotary blade (3) to stop rotating when it detects an abnormal vibration state of the machine body (1).

2. 2. The wireless-controlled grass trimmer according to claim 1, wherein, when the acceleration sensor (7) detects an abnormal vibration state, the motor (5) is stopped, or the power transmission to the rotary blade (3) is turned on and the cutting-enabled blade clutch (6) is disengaged, or both of these are performed.

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