JPH036189Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention is an automatic pruning machine equipped with an endless saw blade that ascends spirally around a tree trunk to automatically prune the trunk. This invention relates to an automatic control device for an automatic pruning machine that automatically avoids problems caused by the cutting of an endless saw blade chain into a branch.

[Prior Art] An automatic pruning machine has been proposed as a device for pruning tall trees instead of using human power. The automatic pruning machine includes, for example, a frame body and a plurality of support wheels for attaching the main body of the device so that it can freely rotate around the tree trunk;
An internal combustion engine as a prime mover fixedly installed in the main body of the device, a drive belt that receives power transmitted from the internal combustion engine via a transmission shaft and a speed reducer, and moves the frame body vertically while rotating around the trunk of the tree. , a chain guide bar protruding in the length direction of the tree trunk at the upper position of the automatic pruning machine, and an endless saw blade chain (hereinafter simply referred to as chain). When an automatic pruning machine with such a configuration is installed at the bottom of a tree, the chain slides under the power of the internal combustion engine, and the drive belt operates, moving upward around the tree trunk and spiraling on its own. The tree progresses in a straight line, and as it progresses, pruning is performed using a chain.

[Problems to be solved by the invention] Even with the above-mentioned chain-type automatic pruning machine, which is less prone to digging into branches than the circular saw type or reamer type, it is difficult to cut the tip of the branch during pruning. When this is done, there is a risk that the chain will dig into the branch.
Here, tip cutting refers to a situation where the tip of the chain guide bar with a small effective cutting width hits a branch while moving, and the chain at the tip cuts the branch. In this case, the phenomenon of biting into the branch is likely to occur. . When the chain bites into the branch in this way, the output shaft of the internal combustion engine and the sprocket shaft of the chain are connected via the centrifugal clutch mechanism, which consists of the clutch body and the clutch outer ring. There is a risk of slipping between the parts, causing problems such as overheating and abnormal wear of various parts.

The purpose of the present invention is to effectively solve the above-mentioned problem by automatically releasing the chain from cutting into the branch when the chain gets stuck in the branch due to tip cutting during pruning. Another object of the present invention is to provide an automatic control device for an automatic pruning machine that automatically controls the rotational speed of an internal combustion engine when the release cannot be performed, and avoids problems without bothering the user.

[Means for Solving the Problems] The automatic control device for the automatic pruning machine according to the present invention detects the locked state of the chain by using a clutch outer ring rotation sensor when the chain bites into a branch due to tip cutting or the like and becomes locked. First, the device that raises and lowers the pruning machine body is controlled by an up/down signal output circuit, and the pruning machine is lowered for a certain period of time to release the pruning machine. If it is not possible to release the centrifugal clutch, the motor control signal output circuit controls the rotational speed of the motor, including stopping it, to a rotational speed at which the centrifugal clutch is disengaged.

[Example] An example of the present invention will be described below with reference to the drawings.

First, an overview of the automatic pruning machine to which the present invention is applied will be given. As shown in FIG. 2, the automatic pruning machine 100 includes:
A frame body 1 that can be closed so as to embrace the tree trunk T to be pruned, and pulleys 2 and 3 are installed on one side of the frame body 1 (the front side in the figure) so as to be inclined with respect to the length direction of the tree trunk T. An endless drive belt 4 that is rotatably provided and in contact with the surface of the tree trunk T;
An internal combustion engine 7, such as a small air-cooled two-stroke gasoline engine, which is attached to the frame body 1 and serves as a prime mover that rotationally drives the pulley 2 via a transmission shaft 5, a speed reducer, and a rotational direction converter 6; It has a plurality of support wheels 8 which are rotatably attached at an angle to the tree trunk and cooperate with the endless drive belt 4 to hold the tree trunk T and move the frame 1 up and down while spirally turning around the tree trunk T. .

Further, a chain guide bar 9 is provided upward from the top of the frame body 1 in parallel with the tree trunk T and protrudes in the length direction of the tree trunk T while maintaining a constant interval, and an endless saw blade chain 10 is slid around the bar 9. Mounted so that it can run. The chain 10 is driven by the internal combustion engine 7 via a transmission mechanism including a centrifugal clutch mechanism. The centrifugal clutch mechanism consists of a clutch body connected to the output shaft 11 of the internal combustion engine 7 and a clutch outer ring 26 connected to a chain drive sprocket (not shown). When the chain 10 bites into a branch, the sliding motion of the chain 10 is locked, causing slippage between the clutch body and the clutch outer ring.

The automatic pruning machine 100 includes a control circuit unit 12
As will be described later, this control circuit unit 12 controls the operation of the rotational direction converter 6 under predetermined conditions to change the rotational direction of the endless drive belt 4 in a predetermined procedure to operate the automatic pruning machine 100. In addition to moving up and down, in this embodiment, the power switch (not shown) for the internal combustion engine 7 is automatically turned off to stop the operation of the internal combustion engine, if necessary. That is,
Acts as an automatic control device. This automatic control operation of the control circuit unit 12 is carried out on the basis of the output signal (clutch signal) of the clutch outer ring rotation sensor 14, which makes it possible to determine the rotation period of the internal combustion engine 7.

Control circuit unit 12 with reference to FIG. 1 showing the basic overall configuration and FIG. 6 showing a specific circuit example.
A circuit for realizing an automatic control device according to the present invention included in the present invention will be described. This circuit includes an oscillator 13 that outputs a clock pulse (1Hz), a clutch outer ring rotation sensor 14 that outputs a clutch signal S1,
An initial state detection circuit A consisting of an internal combustion engine rotation period detection circuit (hereinafter referred to as a period detection circuit) 15 and an initial counter 16, a down counter 17, a down signal holding circuit 18, and an up signal generation and holding circuit 1.
9, three AND gates 20, 21, 22, and one OR gate 23, a down/up signal output circuit B, a stop counter 24, and one
It consists of a stop signal output circuit C consisting of an AND gate 25. A clock pulse from the oscillator 13 is supplied to an initial counter 16, a down counter 17, a down signal holding circuit 18, an up signal generation and holding circuit 19, and a stop counter 24. A clutch signal S1 from the clutch outer ring rotation sensor 14 is supplied to a period detection circuit 15, a down counter 17, and a stop counter 24.

The clutch outer ring rotation sensor 14 is, as shown in FIG. It is a contact sensor. The peripheral wall 26a of the clutch outer ring 26 is formed with two holes or recesses 26b at symmetrical positions. The electromagnetic pickup coil 27 has an iron core 27a connected to the clutch outer ring 2.
A permanent magnet 27b is disposed perpendicularly to the outer surface of the peripheral wall 26a of the iron core 27a.
Coils 27c are provided around each iron core 27a. According to this mounting relationship, when the clutch outer ring 26 is rotating as shown by the arrow in FIG.
As shown in FIG. 5A, when the hole 26b passes near the inner end of the iron core 27a, the magnetic field lines 28 change and a waveform signal 29 is generated in the clutch signal S1, and as shown in FIG. 5B, only the peripheral wall 26a is generated. No waveform signal is generated when the In this way, the waveform signal 2 generated periodically from the output terminal of the coil 27c of the electromagnetic pickup coil 27 when the clutch outer ring 26 is rotating.
A clutch signal S1 containing 9 is output. In this embodiment, two waveform signals 29 are generated when the clutch outer ring 26 rotates once. On the other hand, when the chain 10 bites into a branch and a locked state occurs, the centrifugal clutch slips and the clutch outer ring 26 stops rotating.As a result, the waveform signal 29 is no longer generated, and the clutch signal S1 becomes a non-signal state.

In the initial state detection circuit A, the rotational speed of the internal combustion engine is controlled by the centrifugal clutch so that the chain slides normally so that the automatic control device does not operate during idle rotation. For example, this is a circuit that sets the down/up signal output circuit B and the stop signal output circuit C to the active state when the engine speed reaches 7000 rpm or more, and the automatic control device operates when it is not necessary, such as immediately after starting the internal combustion engine 7. can be prevented.

As shown in FIG. 6, the period detection circuit 15 includes flip-flops F ₁ , F ₂ , resistors R ₁ , R ₂ ,
It consists of R ₃ , capacitor C ₁ , and npn type transistor T _r1 . The clutch signal S1 from the clutch outer ring rotation sensor 14 is transmitted through diodes _D1 , _D2 , npn transistor _Tr2 , resistors _R4 , _R5, and NOT gate 3.
The signal is adjusted by a signal adjustment circuit 31 consisting of 0 to form a rectangular pulse as shown in FIG. 7, and is supplied to flip-flops F ₁ , F ₂ , etc. In the period detection circuit 15, the waveforms of each part of the circuit in FIG. 6 generated by the clutch signal supplied from the NOT gate 30, namely, the node P ₁ , the output Q ₁ ,
The waveforms of Q ₁ , Q ₂ , and ₂ are as shown in FIG. As is clear from FIG. 7, as the rotational speed of the internal combustion engine 7 increases, the pulse period of the clutch signal becomes shorter, and when the rotational speed reaches a predetermined 7000 rpm,
It becomes impossible to charge the capacitor _C1 to a predetermined level, and as a result, ₂ is held at L (low level), making it possible to detect that the rotational speed of the internal combustion engine has exceeded 7000 rpm. The output ₂ obtained in this way is the initial counter 1
given to 6.

In more detail, the initial counter 16 is composed of a counter 32, an OR gate 33, an AND gate 34, and a NOT gate 35, as shown in FIG. A required low level signal is input to the counter 32 from a circuit 37 consisting of a resistor R ₆ , a capacitor C ₂ , a diode D ₃ and a NOT gate 36 via an OR gate 33 and an AND gate 34 . is input. When the output ₂ is H (high level), the output of the counter 32 is kept at L, and when the rotational speed of the internal combustion engine 7 reaches 7000 rpm and the output ₂ becomes L, the counter 32 starts counting clock pulses, and when t After a second, the output is set to H. In this way, the rotation speed of the initial counter 16 is 7000 rpm.
A high level signal is output t seconds after reaching the above value.

In the down/up signal output circuit B, while the clutch signal containing periodic square pulses is input from the NOT gate 30, the down counter 17 clears the count amount by this clutch signal. No counting operation is performed. When the clutch signal becomes non-signal, the clock pulses are counted and the output is set to H after _t1 seconds.

More specifically, the down signal holding circuit 18 includes a flip-flop _F3 , a counter 38, and a NOT
It is composed of a gate 39 and an OR gate 40. The output of the AND gate 20, into which the outputs of the counters 17 and 32 are input, is supplied to the flip-flop _F3 via the NOT gate 39, and when the output of the AND gate 20 is H, the counter 38 is counted by one output of the flip-flop _F3 . While maintaining the enable state, the other output is given to the OR gate 23 as a down signal. When the counter 38 is set to the countable state as described above, the counter 38
counts the clock pulses given from the oscillator 13, sets its output to H after _t3 seconds, and sets the output given to the OR gate ₂₃ of flip-flop F3 via the OR gate 40 to L. In this way, the down signal holding circuit 18 holds the down signal for _t3 seconds.

To be more specific, the up signal generation and holding circuit 19 includes a flip-flop _F4 and a counter 4.
1 and an OR gate 42. One output of the flip-flop _F3 is a flip-flop
When the down signal disappears, one output of _the flip-flop _F4 holds the counter 41 in a countable state, and the other output is applied to the AND gate 22 as an up signal. When the counter 41 is set to a countable state as described above, the counter 41 counts the clock pulses given from the oscillator 13, sets its output to H after _t4 seconds, and outputs the clock pulse to the OR gate 42.
AND gate 22 of flip-flop F ₄ through
Let L be the output given to . In this way, the up signal generation and holding circuit 19 generates an up signal and holds it for _t4 seconds.

Stop counter 2 of stop signal output circuit C
4 does not perform the required counting operation while the clutch signal containing periodic square pulses is input from the NOT gate 30 because the count amount is cleared by this clutch signal. When the clutch signal becomes non-signal, it starts counting clock pulses and sets its output to H after _t2 seconds. Also
A drive circuit consisting of a resistor _R7 and an npn transistor _Tr3 is provided on the output side of the AND gate 25.

In addition, in FIG. 6, AND gates 20, 21,
22, 25, and OR gate 23 are the same as those shown in FIG. 1, so they are given the same reference numerals. Also
The output of NOT gate 36 is a flip-flop
It is given to the reset terminals of F ₂ , F ₃ , and F ₄ .

Next, the operation of the device of the present invention will be explained based on FIGS. 1, 2, and 3. The automatic pruning machine 100 is attached to the lower part of the tree to be pruned, and the internal combustion engine 7
When started, power is applied to the chain 10 via the output shaft 11, clutch mechanism, and chain drive sprocket, and the chain 10 slides around the bar 9, and also moves the transmission shaft 5, reducer, rotational direction converter 6, and pulley 2. The endless drive belt 4 rotates through the automatic pruning machine 10.
0 begins to climb on its own along the tree trunk T while turning. At this time, the rotational state of the clutch outer ring 26 is detected by the clutch outer ring rotation sensor 14, and a clutch signal consisting of a pulse signal is supplied to the circuit of the automatic control device in the control circuit unit 12. However, the rotational speed of the internal combustion engine 7 is
When the speed is lower than 7000rpm at which the motor starts sliding normally, the circuit is not set to the active state, and when the speed reaches 7000rpm or higher, this is detected by the period detection circuit 15.
After t seconds after this detection, the output of the initial counter 16 transitions from L to H, and the AND gates 20, 21,
22 and 25 are opened to set the circuit to the active state.

While the automatic pruning machine is smoothly performing the pruning operation, there is substantially no slippage between the clutch body and the clutch outer ring in the clutch mechanism. Therefore, the clutch signal supplies periodic pulses to the circuit so that no circuit action occurs.

When a wedge condition occurs between the chain 10 and a branch due to a tip cutting phenomenon or the like, the chain 10 becomes locked. Due to this lock state, chain 1
The clutch outer ring 26, which had been rotating together with the clutch outer ring 26, stops rotating, and continuous slipping occurs between the clutch outer ring and the clutch body, which continues to be driven by the internal combustion engine 7. The stopped state of the clutch outer ring 26 is detected when the clutch signal S1 becomes non-signal. When the clutch signal becomes non-signal, the down counter 17 and the stop counter 24 start counting operations. t Down counter 17 after ₁ second
The output becomes H, and the down signal is passed to AND gate 2.
0, the OR gate 23, and the AND gate 21. This down signal activates the rotation direction changer 6, reverses the rotation direction of the endless drive belt 4, and lowers the automatic pruning machine 100.
The down signal output from the down counter 17 disappears when the chain 10 comes off the branch and resumes sliding, and the clutch outer ring rotation sensor 14 outputs a periodic pulse again. But AND gate 2
The zero output is also supplied to a down signal holding circuit 18, by which the down signal is held for _t3 seconds, during which time the automatic pruning machine continues to descend.

The down signal from the down signal holding circuit 18 is _t3
When the signal disappears after a second, the up signal generation and holding circuit 19 generates an up signal and holds it for _t4 seconds. This up signal is outputted via the AND gate 22 to operate the rotation direction changer 6,
The direction of rotation of the endless drive belt 4 is reversed again and the automatic pruning machine is raised. In this way, chain 10
If the chain gets stuck in a branch, the automatic pruning machine 100 is automatically lowered, and when the chain 10 comes off the branch, it is raised again, thereby automatically releasing the stuck state. .

If the jamming state cannot be released by the above-mentioned digging release operation, that is, if it cannot be lowered even if a down signal is generated, the stop counter will be reset t ₂ seconds after the jamming state occurs. The output of 24 changes from L to H, and a stop signal is output. This stop signal is outputted via the AND gate 25 and turns off a power switch (not shown) for the internal combustion engine 7.
As a result, the operation of the internal combustion engine 7 is automatically stopped. In the above case, it is set so that t ₁ <t ₂ .

In addition, for the purpose of eliminating the trouble of restarting the internal combustion engine, the stop signal may be used as a control signal to lower the rotational speed of the internal combustion engine to an idling speed below the rotational speed at which the centrifugal clutch disengages, and the design is free. It is.

[Effects of the invention] As explained above, according to the invention, an automatic pruning machine is equipped with a sensor that detects the stopped state of the clutch outer ring when the chain bites into a branch due to the tip cutting phenomenon, etc., and an automatic pruning machine. The clutch mechanism is equipped with an automatic control device consisting of a circuit that automatically releases the jamming by moving the machine up and down, and a circuit that controls the rotation speed of the prime mover to below the rotation speed at which the clutch disengages when it cannot be released. This prevents overheating and abnormal wear of various parts due to slippage, eliminates the need for manual release work by the operator when a wedge occurs, and also prevents damage to the machine body.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram showing the overall configuration of an automatic control device according to the present invention, and FIG. 2 is a partially cutaway side view schematically showing an automatic pruning machine to which the present invention is applied.
Fig. 3 is a timing chart showing the operation of the automatic control device, Fig. 4 is a configuration diagram of the clutch outer ring rotation sensor, Fig. 5 is a diagram of the signal generation principle of the clutch outer ring rotation sensor, and Fig. 6 is a diagram of the automatic control device. Specific circuit example diagram,
FIG. 7 is a timing chart showing output waveforms of each part of the initial state detection circuit. In the drawing, 2 and 3 are pulleys, 4 is an endless drive belt, 6 is a speed reducer and rotation direction changer, 7 is an internal combustion engine, 9 is a chain guide bar, 10 is an endless saw blade chain, 12 is a control circuit unit, 13 14 is an oscillator, 14 is a clutch outer ring rotation sensor, 26 is a clutch outer ring, 27 is an electromagnetic pickup coil, A
1 is an initial state detection circuit, B is a down/up signal output circuit, and C is a stop signal output circuit.

Claims (1)

[Scope of utility model registration request] An automatic pruning machine including a prime mover, an endless saw blade chain operated by the power thereof, and a device for raising and lowering the saw blade while rotating around a tree trunk, wherein a centrifugal clutch transmits the power from the prime mover to the endless saw blade chain. a clutch outer ring rotation sensor that detects rotation or stoppage of the clutch outer ring and generates a clutch signal; an oscillator that generates a clock pulse; and a clutch outer ring rotation sensor that inputs the clutch signal and the clock pulse to detect whether the endless saw blade chain has cut into a branch. A down/up signal output circuit outputs a down signal and an up signal for raising and lowering the branching machine body, respectively, and a down/up signal output circuit receives the clutch signal and the clock pulse and outputs a branching signal from the down/up signal output circuit. The automatic pruning device is characterized by comprising a prime mover control signal output circuit that outputs a prime mover control signal that causes the rotational speed of the prime mover to be lower than the rotational speed at which the centrifugal clutch is disengaged when the cutting machine body cannot be lifted or lowered and the biting cannot be released. Machine automatic control device.