JPS59133802A - Remote controller - Google Patents

Abstract

PURPOSE:To prevent the formation of dangerous state which an operator can not anticipate in crane operation by allowing a remote control function to be automatically suspended when a potentiometer circuit for setting or feedback is broken or short circuited. CONSTITUTION:When wire snapping is generated between the slider of a potentiometer 1 and a power source Vdd, a relay Ry2 is put into non-excited state, and a contact r2 is opened, and supply of voltage to the emitters of transistors 14 and 15 is suspended, and solenoid valves 7 and 8 are opened. Therefore, a piston 2 is positioned at a neutral position, and transfer of a hydraulic cylinder 27 is suspended. The contact r1 of a relay R1 is opened with a delay of 0.5sec. by the aid of a delayed timer 18, after the contact r2 is opened, and a solenoid valve 8 is closed to cut-off the working oil supplied by a hydraulic pump P. Thus, remote-control function is automatically suspended, and the formation of dangerous state can be avoided.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a remote control device that stops the remote control function when a setting or feedback potentiometer is disconnected or short-circuited.

Conventional remote control devices, such as crane remote control devices, control the operation of the crane, i.e. the position of the winch,
A setting potentiometer provided corresponding to each hydraulic cylinder for controlling specifications such as boom extension and contraction, boom raising and lowering, and boom rotation, and a setting potentiometer provided corresponding to the setting potentiometer and connected to the hydraulic cylinder. A directional control valve that controls the amount of operating oil to be supplied and switches the direction.Equipped with a pilot hydraulic cylinder that fully drives the pilot hydraulic cylinder, and a feedback potentiometer that detects the piston position of the pilot hydraulic cylinder, and a potentiometer output for setting and feedback. The comparative output is used to control the moving direction and moving speed of the hydraulic cylinder via the pilot hydraulic cylinder and the direction switching valve.

However, when using the conventional remote control device as described above,
Even if the setting or feedback potentiometer is disconnected or short-circuited, the hydraulic cylinder is controlled by the setting and feedback potentiometer outputs, and the hydraulic cylinder is moved in a direction unexpected by the operator at an unexpected speed. This has the disadvantage that the tip of the hook or boom may hit surrounding objects, creating a dangerous situation.

The present invention has been conceived and set forth above.

The purpose of the present invention is to provide a remote control device that eliminates the above-mentioned drawbacks by automatically stopping the remote control function when a potentiometer for use or feedback or its lead wire is disconnected or short-circuited. do.

The present invention will be explained below using examples.

FIG. 1 is a block diagram showing a remote control device according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing an example of the safety circuit shown in FIG. 1.

This embodiment exemplifies the case of a remote control device that remotely controls an on-vehicle crane, and includes a setting potentiometer L that is biased to return to a neutral position by a spring when no external force is applied to the slider, and a crane drive means. The pilot hydraulic cylinder 2 constitutes a part of the hydraulic cylinder 2. The crane driving means includes a hydraulic cylinder 27 that directly controls the crane, and a directional control valve 25 that controls the direction and amount of supply of operating oil to both chambers of the hydraulic cylinder 27 by the piston position of the pilot hydraulic cylinder 2.

Reference numeral 26 denotes a manual lever for controlling the directional switching valve 25 by manual operation.

4 is a key switch that turns on and off the voltage of the on-vehicle storage battery 3. The output voltage of the key switch 4 is supplied to the potentiometer 1 via a power switch 5 which controls the power supply voltage supply to the crane remote control device. The pilot hydraulic cylinder 2 includes a normally closed solenoid valve 6 that supplies operating oil from a pump P (not shown) to the pilot hydraulic cylinder 2;
Normally open solenoid valves 7 and 8 and pilot hydraulic cylinder 2
A foot check potentiometer 9 detects the positions of the two pistons in the cylinder, and a solenoid valve 7 selectively directs operating oil from the solenoid valve 6 into one chamber Sl of the pilot hydraulic cylinder 2 or to the solenoid valve 8. The control oil from the solenoid valve 7 is selectively guided into the other chamber S2 of the pilot hydraulic cylinder 2 or into the oil tank R (not shown) by the solenoid valve 8, and the potentiometer 9 is equipped with a power switch. 5 output voltage VDD is applied.

The output voltage of potentiometer 1 is applied to resistor 8,
The voltage across resistor R8 is supplied to voltage follower 10, and the output voltage of potentiometer 9 is applied to resistor R9.
The voltage across resistor R9 is supplied to voltage follower 11.

The crane remote control device includes a differential amplifier 12 to which the output voltage of the voltage follower 10 is supplied as one input voltage and the output voltage of the voltage follower 11 is supplied as the other input voltage, and the output voltage of the voltage follower 10. A neutral position detector 13 that detects that the voltage is within a predetermined range that includes the midpoint voltage of the potentiometer 1, and a differential amplifier 1.
The output voltage of transistor 14 or /
and a logic operation circuit 16 that drives transistors 14 and 15 and controls transistors 14 and 15 to be off according to the output voltage of neutral position detector 13.
4 excites the solenoid valve 7 with its output, and the transistor 15 is configured to excite the solenoid valve 8 with its output.

On the other hand, the output voltage of the storage battery 3 outputted via the key switch 4 is supplied to the emitters of the transistors 14 and 15 as a power supply voltage, and the output voltage of the storage battery 3 outputted via the key switch 4 is It is supplied to the solenoid valve 6.

Below, the output voltage of potentiometer 1 is ■IN1 The output voltage of potentiometer 9 is VF1 Voltage follower 10
The output voltage of the voltage follower 11 is indicated by V engineering N', and the output voltage of the voltage follower 11 is indicated by ■F'. Output voltage VIN"Output voltage VIN'
, the output voltage ■Fz and the output voltage ■F'.

In one embodiment of the invention, a safety circuit 17 is also provided, to which the output voltage of the voltage follower 10 and the output voltage of the voltage follower 11 are supplied.

The safety circuit 17 includes diodes D1 to D as shown in FIG.
4 and bias current supply resistors ``1'' and ``2'' select the larger output voltage and the smaller output voltage of the output voltage VIN' of the voltage follower 10 and the output voltage ■F' of the voltage follower 11. Selection circuit 19
and a voltage divider circuit 20 which is made up of resistors R3 to R5 and divides the voltage VD'D output from the power switch 5, and the output voltage of the voltage divider circuit 20 is supplied as a reference voltage and the output voltage of the selection circuit 19. It is equipped with a window controller 21 consisting of oven collector type comparators C1 and C2 to which is supplied as a comparison voltage, and a transistor 22 which is driven by the output of the window comparator 21 and fully drives the relay Ry2. contact r2
is a key switch that supplies the emitters of transistors 14 and 15; it is configured to turn on and off the output voltage of transistor 4.

The selection circuit 19 connects the output chamber/pressure VIN' of the voltage follower 10 to the connection point between the cathode of the diode D1 and the anode of the diode D2, and connects the voltage follower 11 to the connection point of the anode of the diode D3 and the cathode of the diode D4.
The output voltage ■F' is supplied, and the larger voltage of voltages VIN' and ■F' is output from the connection point between the cathode of the diode D2 and the cathode of the diode D3, and compared to the inverting input terminal of the comparator C1. Supplied as voltage, diode D1
The smaller of the voltages VIN' and vF is output from the connection point between the anode of the diode D4 and the anode of the diode D4, and the comparator C
It is supplied as a comparison voltage to the non-inverting input terminal of No. 2.

The sum of the divided voltages applied to resistors R4 and R5 is supplied to the non-inverting input terminal of comparator C1 as a reference voltage A, and the sum of the divided voltages applied to resistor R5 is supplied to the inverting input terminal of comparator C2. The divided voltage is supplied as the reference voltage vB.

The comparator C1 is provided with a holding circuit 23 consisting of a series circuit of a diode D5 and a resistor R6 connected between the non-inverting input terminal and the output terminal of the comparator C1.
2 is provided with a holding circuit 24 consisting of a series circuit of a diode D6 and a resistor R7 connected between the non-inverting input terminal and the output terminal of the comparator C2.

Further, in one embodiment of the present invention, a delay timer 18, for example, is provided for a predetermined period of time after the voltage supplied to the emitter of the transistor 14.15 via the contact r2 is cut off. The output contact r1 is configured to cut off the voltage supplied to the solenoid valve 6 with a delay.

In addition, each of the above components includes a storage battery 3, a key switch 4,
It goes without saying that, except for the power switch 5, the components are provided in accordance with the controlled specifications of the crane.

In addition, in the above, the resistor R constituting the voltage dividing circuit-20
3. The resistance value of 几4 and R5 is the reference voltage of comparator C1■
H becomes slightly higher than the high voltage output of the voltage follower 10.11 when the potentiometer 1.9 is in normal condition. The output voltage VIN' of the voltage follower 1O111 in the normal state of 9 is set to be slightly lower than the low voltage output of ■F'.
The resistance value of the resistor R8 connected to the input terminal of the voltage follower 10 is set to be much larger than the sum of the resistance value of the potentiometer 1 and the resistance value of one resistor connected to the power supply side of the potentiometer 1. Also voltage follower 1
The resistor R9 connected to the input terminal No. 1 is also set in the same manner.

In a practical example of the present invention configured as described above, when the potentiometers 1 and 9 are normal, the output voltages VIN and ■F' of the potentiometers 1 and 9 output through the voltage followers 10 and 11 Both are voltages between the reference voltage .H of the comparator C1 and the reference voltage vL of the comparator C2. Therefore, the output of the window comparator 21 is at a high potential, and the transistor 22
is controlled to be on. As a result, relay Ry2 is energized and the output voltage of storage battery 3 is supplied to the emitters of transistors 14 and 15 via key switch 4. On the other hand, the delay timer 18 is activated by the output voltage of the key switch 4 through the contact r2.
Since the solenoid valve 6 is controlled to be on, the solenoid valve 6 is excited, and the operating oil pressurized by the hydraulic pump P is supplied via the solenoid valve 6. In this state, potentiometer 1
By operating the υ pilot hydraulic cylinder 2, the crane can be remotely controlled via the hydraulic cylinder 27.

Now, if the set point of the potentiometer 1 is within a predetermined range that includes the midpoint position, the output voltage of the potentiometer 1 will be within the predetermined voltage range that includes the midpoint voltage, and the neutral position detector 13 will generate an output, and the logic Arithmetic circuit 16 controls transistors 14 and 15 to turn off. Therefore, solenoid valves 72 and 8 are de-energized. As a result, both electromagnetic valves 7 and 8 become open. For this reason (
The two pistons of the pilot hydraulic cylinder 2 are in a free state and are at the midpoint position (by the action of the return spring of the directional control valve 25). In this state, the positions of the two pistons can be controlled by operating the manual lever 26.

If the slider of potentiometer 1- is within a predetermined range sandwiching the midpoint position, operate the slider of potentiometer to set the output voltage V-N of potentiometer 1 to a high value, and the differential amplifier The input voltage of 12 is VIN'>
VF', and the logic operation circuit 16 controls only the transistor 14 to be in the on state. Therefore, solenoid valve 7
is excited and the valve is closed. On the other hand, the solenoid valve 8 is not energized and is in an open state. As a result, the operating oil from the hydraulic pump P is guided to the chamber S1 side of the pilot hydraulic cylinder 2 via the solenoid valve 6, and the oil from the chamber S2 side is guided to the oil tank R via the solenoid valve 8, and the oil from the chamber S2 side is guided to the oil tank R via the solenoid valve 8. The two people move to the right in Figure 1. The movement of the two pistons to the right causes the directional control valve 25 to change the direction of the operating oil to the hydraulic cylinder 27, and the hydraulic cylinder 27 is driven to the right in FIG. Further, the moving speed of the hydraulic cylinder 27 in the rightward direction is proportional to the amount of deviation of the slider of the potentiometer 1 from the midpoint position. On the other hand, two pistons
By moving to the right side, the output voltage of the potentiometer 9 increases, and when the voltage vF=VIN, the logic operation circuit 16
controls transistors 14 and 15 to be on.

As a result, the solenoid valves 7 and 8 are closed, and the positions of the two pistons are locked.

For this purpose, the piston of the hydraulic cylinder 27 moves to the right at a speed corresponding to the slider position of the potentiometer 1, as described above. This movement of the piston of the hydraulic cylinder 27 allows the slider of the potentiometer 1 to be released when the crane reaches the draft position, and the slider of the potentiometer 1 returns to the midpoint position. When the slider of the potentiometer 1 returns to the midpoint position, the midpoint position detector 13 detects this,
As described above, the two pistons are returned to the midpoint position by the output of the neutral position detector 13. When the two pistons return to the neutral position, the operating oil to the hydraulic cylinder 27 is cut off, and the piston position of the hydraulic cylinder 27 is maintained at the position immediately before the two pistons return to the neutral position.

Conversely, if the output voltage VIN of the potentiometer 1 is set low, VIN'< vF/, and the logic operation circuit 16 controls only the transistor 15 to be in the on state. Therefore, the solenoid valve 7 is in a de-energized state and in an open state, and the solenoid valve 8 is energized and in a closed state.

As a result, the operating oil from the hydraulic pump P is guided to the chambers S1 and S2 of the pilot hydraulic cylinder 2 via the solenoid valves 6 and 7. Piston 2A on chamber SL side
The area of the pressure receiving part of the piston on the side of chamber S2 and the area of the pressure receiving part of the two pistons on the side of chamber S2 are set at a ratio of 1:2.
When the operating oil is introduced, the two pistons move to the left in Fig. 1. As the two pistons move to the left, the direction switching valve 25 switches the direction of operating oil to the hydraulic cylinder 27, and the hydraulic cylinder 27 is driven to the left in FIG. Also, the hydraulic cylinder 27. The speed of movement of the potentiometer 1 in the left direction is proportional to the amount of deviation of the slider of the potentiometer 1 from the midpoint position. On the other hand, due to the movement of the two pistons to the left, the output voltage of the potentiometer 9 decreases, and when it reaches the voltage VF'``vIN', the logic circuit 16
controls transistors 14 and 15 to be on.

When the voltage reaches VF""VIN', the positions of the two pistons are locked as in the case described above. As a result, the piston of the hydraulic cylinder 27 moves to the left at a speed corresponding to the slider position of the potentiometer 1. Hydraulic cylinder 27
If the slider of potentiometer 1 is released when the crane reaches a predetermined position due to this movement to the left side of The piston stops at the position just before the two pistons return to the neutral position.

Next, for example, the slider of potentiometer 1 and the power supply V
When a disconnection occurs between the voltage follower 10 and the DD, the input voltage V of the voltage follower 10 decreases due to the presence of one resistor R8.
IN becomes the ground potential. Therefore, since ■IN'(-0)<VF', the selection circuit 19 supplies ■F' as a comparison voltage to the comparator C1, and supplies VIN'(-0) as a comparison voltage to the comparator C2. However, the output voltage F' of the potentiometer 9 output from the voltage follower 11 does not exceed the reference voltage vH, but the output voltage MIN' (=O) of the voltage follower 10 does not exceed the reference voltage v.
It is lower than L. Therefore, the output of the comparator C2 becomes approximately the ground potential, and the transistor 22 is controlled to be in an off state. As a result, relay Ry2 becomes de-energized, contact r2 is opened, voltage supply to the emitters of transistors 14 and 15 is stopped, and remote control by potentiometer 1 is disabled. That is, since the supply of voltage to the emitters of transistors 14 and 15 is stopped, solenoid valves 7 and 8 are brought into a non-energized state and are forced into an open state. As a result, the two pistons become free, and due to the action of the return spring of the directional control valve 25, the positions of the two pistons become the midpoint position, the movement of the hydraulic cylinder 27 is stopped, and the output of the potentiometer 1 is changed. The piston 2A of the servo hydraulic cylinder 2 does not move, and the piston of the hydraulic cylinder 27 also stops moving.

In addition, since the contact r2 is opened, the υ contact r2
The set time of delay timer 18 (05
seconds), relay Ry1 becomes de-energized and contact r
1 is released. As a result, the solenoid valve 6 becomes de-energized and closes, cutting off the operating oil from the hydraulic pump P.

The reason why the closing time of the solenoid valve 6 is delayed by υ compared to the opening time of the solenoid valves 7 and 8 is as follows.

When the emitter voltage of the transistors 14 and 15 is cut off and the solenoid valves 7 and 8 are opened, the force of the return spring of the directional control valve 25 attempts to return the two pistons to the neutral position. When the solenoid valve 6 is closed at the same time as the valve 8 is opened, the chamber S of the pilot hydraulic cylinder 2
Because the solenoid valve 6 is closed, no oil flows inside the chamber S1 or the chamber S2, resulting in negative pressure inside the chamber S1 and the chamber S2. Therefore, there is a possibility that the two pistons will not return to the midpoint position immediately and the crane will continue to operate7.
5; Yes. To avoid this phenomenon, the closing of solenoid valve 6 is delayed by 0.5 seconds from the opening timing of solenoid valves 7 and 8, and
This is to prevent negative pressure inside the room S2 and inside the room S2.

Also, when the output voltage of comparator C2 becomes ground potential, the resistor R
Feedback is applied to the non-inverting input terminal of comparator C2 via resistor R6, and at the same time, feedback is applied to the non-inverting input terminal of comparator C1 via resistor R6. Therefore, the potential at the non-inverting input terminal of the comparator C2 becomes 1 zero potential at tt, which is maintained lower than the potential at the inverting input terminal. Further, the potential of the inverting input terminal of the comparator C1 is held lower than the potential of the non-inverting input terminal. This is a state in which the holding function is activated, and the holding function is not released unless the -transformer power switch 5 is turned off and the power supply voltage VDD of the comparators C1 and C2 is once made zero.

If a wire breaks between the slider of the potentiometer 1 and the ground, the input voltage VIN of the voltage follower 10 will be equal to the resistance value Ra of the resistor 1, the power supply end of the potentiometer 1, and the slider. The resistance value Rb between
The voltage ■DD applied to the resistor R8 when the output voltage ■DD of the power switch 5 is divided by the resistance value RC of the resistor R8! (l
C/(Ra+Rb+R6).

Here, since the resistance value Rc of the resistor R8 is set to be sufficiently larger than Ra+Rb, the input voltage VIN of the voltage follower 10 becomes higher than the output voltage vF of the potentiometer 9 and the reference voltage 2H. Therefore, the output voltage VIN' of the voltage follower 10 is higher than the output voltage ■F' of the voltage follower 11, and is also higher than the reference voltage ■H.
Output voltage of voltage follower 1o■■N' is selection circuit 1
The output voltage vF' of the voltage follower 11 is selected by a selection circuit 19 and supplied to the comparator C2 as a comparison voltage. However, in this case, as described above, since the comparison voltage of the comparator C1 is higher in potential than the reference voltage VH, the output voltage of the comparator C1 becomes the ground potential. Therefore, relay Ry
2 becomes de-energized and the voltage to the emitters of transistors 14 and 15 is cut off, making remote control impossible.

Furthermore, relay Ry1 becomes de-energized with a delay of 0.5 seconds.

Therefore, the same effect occurs as in the case where there is a disconnection between the slider of the potentiometer 1 and the power supply VDD as described above. In addition, resistors R are connected to the non-inverting input terminals of comparators C1 and C2.
6 and 7, respectively, and the potential at the non-inverting input terminal of the comparator C2 becomes lower than the potential at the inverting input terminal, reaching the holding state.

Furthermore, although the above description has been made using the example of a disconnection on the potentiometer 1 side, VH<VIN', not limited to disconnection, but also when a short circuit occurs on the potentiometer 1 side.
Or (2) When L>VIN', it is detected by the window comparator 21 and operates in the same manner as above.

In addition, the same applies to the potentiometer 9 side, such as wire breakage and
Or due to short circuit etc. Va<VF', t or ■L>VF
When this happens, it is detected by the window comparator 21 and acts in the same way as on the potentiometer 1 side.

As explained above, according to the present invention, it is detected that the output voltage of the setting potentiometer or the feedback potentiometer is outside a predetermined range,
This detection output cuts off the power supply voltage to the transistor that controls the piston position of the pilot hydraulic cylinder, so when the setting potentiometer or feedback potentiometer is disconnected or short-circuited, the remote control is automatically activated. The remote control function of the device is stopped, which has the effect of avoiding a dangerous situation.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a circuit diagram showing an embodiment of the safety circuit according to the present invention. 1 and 9: Potentiometer, 2: Pilot hydraulic cylinder, 4: Key switch, 5: Power switch, 6.7 and 8: Solenoid valve, 10 and 11: Voltage follower, 12: Differential amplifier , 14 and 15
・Transistor, 16 ・Logic operation circuit, 17...
Safety circuit, 18...Delay timer, 19 Selection circuit, 20
...Divider pressure circuit, 21 Window comparator, 25 Directional switching valve, 27 Hydraulic cylinder, Ryl and Ry2
Relay, rl and r2・Relay contact, C1 and C2... Comparator, R8 and R9・Resistor. Patent applicant: Diesel Equipment Co., Ltd., patent attorney, Nobuo Sunako

Claims (2)

[Claims] (1) A first potentiometer constituting the operation side, a pilot hydraulic cylinder that controls the piston position of the hydraulic cylinder that drives the driven body via a directional control valve, and a first potentiometer that detects the piston position of the pilot hydraulic cylinder. 2 potentiometer, a solenoid valve that controls the introduction of operating oil into the pilot hydraulic cylinder, and a detection method that detects a difference between the output voltage of the first potentiometer and the output voltage of the second potentiometer. and a transistor that is driven to drive the solenoid valve, the output voltage of the first potentiometer or the output voltage of the second potentiometer falls outside a predetermined range. A remote control device comprising a safety circuit comprising a detection means for detecting this, and a cutoff means driven by the direction of the detection means and cut off the supply voltage to the transistor. (2) The detection means includes a first resistor to which the output voltage of the first potentiometer is applied, a second resistor to which the output voltage of the second potentiometer is applied, and a second resistor to which the first reference voltage is applied. A window comparator consisting of a first comparator and a second comparator to which a second reference voltage having a lower potential than the first reference voltage is applied; selects the higher voltage of the second voltage applied to the resistor and supplies it to the first comparator as a comparison voltage, and selects the lower voltage of the first voltage and the second voltage; 2. The remote control device according to claim 1, further comprising a selection circuit for supplying the reference voltage to the second comparator as a comparison voltage.