JPS634061Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a remote control device for a hydraulic crane.

(Prior Art) In general, when remotely controlling crane operations such as boom hoisting, boom extension/retraction, hoisting and lowering, and left/right rotation in a mobile hydraulic crane, it is necessary to remotely control operation speed as well as operation selection. is necessary.

Conventionally, as a remote control device for hydraulic cranes,
JP-A-51-108181 discloses that a variable relief valve is provided in the pressure oil supply circuit of a hydraulic actuator, and the relief setting pressure of this variable relief valve is adjusted using a mechanical push-pull cable. Remote control of the actuation speed of the actuator is described.

(Problem to be solved by the invention) However, in the configuration in which the relief setting pressure of the variable relief valve is remotely controlled using a mechanical push-pull cable as described above, it is difficult to ensure reliable operation using the cable. In addition to mechanical problems and the problem of requiring a large operating force, there is also a problem that the distance over which remote control is possible is limited.

The purpose of the present invention is to provide a remote control device for a hydraulic crane that allows a worker to easily accelerate and decelerate the crane operation with one hand without being limited by the remote control distance. be.

(Means for Solving the Problems) According to the present invention, as shown in the drawing, the hydraulic oil supply and discharge circuits 3 and 4 connected to the hydraulic pump 1 and the hydraulic oil tank 2 are equipped with a boom hoisting cylinder 5 and a boom telescoping cylinder. 7. Hoisting motor 6 and swing motor 8
Solenoid valves 9 to 12 for operation selection are inserted in oil passages formed by connecting hydraulic actuators for crane operation in parallel, respectively, and the hydraulic pump 1
A relief valve is provided in the oil passage 19 that bypasses the discharge side to the hydraulic oil tank 2 so as to control the discharge side hydraulic pressure of the valve, and is configured to remotely control the switching operation of the operation selection solenoid valve and the set pressure of the relief valve. In the remote control device for a hydraulic crane, the relief valve includes a proportional solenoid relief valve 20, and the operation selection solenoid valves 9 to 12
The operation terminal device 44 is provided with a plurality of operation selection switches 46 to 49 connected to each of the solenoids of the proportional solenoid relief valve 20, and a control potentiometer 51 connected to the solenoid of the proportional solenoid relief valve 20. The device 44 has a handle portion 53 that can be held with one hand, and the axis of the handle portion is located above the handle portion 53 so that the plurality of operation selection switches 46 to 49 can be operated with the thumb of the one hand gripping the handle portion 53. A trigger 60 for operating the potentiometer 51 is provided on the lower side of the handle portion 53 so that it can be operated with the other finger of the one hand, and an operating terminal Device 44 and operation selection solenoid valves 9 to 1
A cable 52 for electrically connecting the operation selection solenoid valves 9 to 12 and the proportional solenoid relief valve 20 is pulled out from the end of the handle portion 53 of this operation terminal device and connected to the operation selection solenoid valves 9 to 12 and the proportional solenoid relief valve 20. It is characterized by being connected.

(Function) According to the remote control device for a hydraulic crane according to the present invention having the above-described configuration, an operator working at a location away from the crane body and the vehicle body can operate the handle portion 53 of the operating terminal device 44 with one hand. Hold it and press the operation selection switch 4 with the thumb of this one hand.
6, 47, 48, or 49 to select an operation and start operations such as raising and lowering the boom, hoisting and lowering the load, extending and retracting the boom, and turning right and left. After that, the potentiometer 51 is turned off by pulling the trigger 60 with the other finger.
, thereby opening the solenoid relief valve 20.
By sequentially increasing the current flowing through the solenoid coil from zero, the pressure of the hydraulic oil in the hydraulic oil supply pipe 3 can be smoothly increased.
By controlling the pressure of hydraulic oil according to the state of boom extension and contraction, the speed of crane operation can be smoothly accelerated and decelerated.

(Example) The present invention will be explained below with reference to the drawings.

Figure 1 shows the basic configuration of the hydraulic circuit of the remote control device according to the present invention.
is a hydraulic pump driven by the engine of the crane truck, 2 is a hydraulic oil tank mounted on the crane truck, 3 is a hydraulic oil supply pipe connected to the discharge side of the hydraulic pump 1, and 4 is connected to the hydraulic oil tank 2. Hydraulic oil discharge pipes 5, 6, 7 and 8 that return hydraulic oil are connected to hydraulic oil supply and discharge pipes 3 and 4 through operation selection solenoid valves 9, 10, 11 and 12, respectively, to oil line 1.
5a, 15b, 16a, 16b, 17a, 17b
and 18a, 18b show the boom hoisting cylinder, hoisting motor, boom telescoping cylinder, and swing motor connected in parallel, and the solenoids of operation selection solenoid valves 9, 10, 11, and 12 are connected in parallel. 11b and 12a, 12b, respectively.

Further, a return bypass oil passage 19 is provided to bypass between the discharge side of the hydraulic pump 1 and the hydraulic oil tank 2 in the above-mentioned hydraulic circuit, and a proportional solenoid relief valve 20 is provided in this bypass oil passage 19.

An example structure of this proportional solenoid relief valve 20 is shown in FIG. In the proportional solenoid relief valve shown in FIG.
A main spool 23 is provided slidably in the axial direction, and a pressure chamber 25 defined by a land 24 provided on the main spool 23 has a port 26 connected to the discharge side hydraulic oil supply pipe 3 of the hydraulic pump 1. A discharge port 27 connected to the hydraulic oil tank 2 is provided, and the main spool 23 is biased by a spring 28 so that the valve operating end 29 of the main spool 23 is always seated on the main valve seat 30 at the discharge port 27. A small hole 31 is provided in the land 24 to pass through it in the axial direction so that the pressure chamber 25 communicates with the upper chamber 32.
is connected to the pilot valve section 3 by the pilot oil passage 33.
A pilot spool 38 is provided in the valve chamber 37 which is connected to the port 35 of No. 4 and communicates with the hydraulic oil tank 2 via the discharge port 36.
9 is provided with a solenoid coil 40, and this coil 4
0 is movable within the magnetic field of the coil magnet 41, and the pilot spool 38 is configured to be pressed against the valve seat 42 with a pressing force proportional to the strength of the current flowing through the coil 40.

The operation of controlling the hydraulic pump discharge pressure, and therefore the hydraulic pressure in the hydraulic oil supply pipe 3, by the proportional solenoid relief valve configured as described above will be explained as follows.
The hydraulic pressure in the hydraulic oil supply pipe 3 generated by the hydraulic pump 1 passes through the port 26 of the main valve section 21, the pressure chamber 25, and the pore 31 to the upper chamber 32, and further passes through the pilot oil line 33 and port 35 to the pilot. Valve part 34
If the hydraulic pressure is lower than the pressure at which the pilot spool 38 is pressed against the valve seat 42, the pilot spool 38 remains seated on the valve seat 42.
The pressure that communicates with the upper chamber 32 through the above-mentioned pore 31 is maintained, so that the pressure chamber 25 and the upper chamber 32
The oil pressure within the chamber is balanced, and the main spool 23 is lightly pressed against the main valve seat 30 by the force of the spring 28, and the pressure chamber 25
The flow of hydraulic oil from the tank to the tank is sealed. Therefore, due to the continuously rotating hydraulic pump 1, its discharge pressure, and therefore the oil pressure in the hydraulic oil supply pipe 3, continues to rise.

In this way, the oil pressure in the hydraulic oil supply pipe 3 increases, and as a result, the oil pressure acting on the pilot spool 38 through the pilot oil line 33 moves the pilot spool 38 generated by the current flowing through the coil 40 to the valve seat. 42, this oil pressure pushes the pilot spool 38 away from the valve seat 42, thereby releasing oil pressure into the tank 2 through the port 36, so that the upper part of the main valve body 21 The pressure in the side chamber 32 decreases,
The port 27 to the tank 2 is opened by pushing up the main spool 23 by the oil pressure in the chamber 25 and pulling the main spool 23 away from the main valve seat 30. In this way, a pressure proportional to the current flowing through the solenoid coil 40 can be maintained in the hydraulic oil supply pipe.

As described above, by sequentially increasing the current flowing through the solenoid coil 40 from zero, the oil pressure within the hydraulic oil supply pipe 3 can be sequentially increased, and the current flowing through the solenoid coil 40 can be increased to a required current. By controlling the coil current to a desired value, the oil pressure at the pump discharge port can be controlled to a desired value in proportion to the coil current.

In carrying out the present invention, the proportional solenoid type relief valve is not limited to the structure described above, and any suitable electro-hydraulic proportional control valve known in the art may be used.

Figure 3 shows the above-mentioned operation selection solenoid valves 9 and 1.
0, 11, 12 and an electric circuit for controlling the proportional solenoid relief valve 20, 43 is a crane main body and vehicle body side circuit, and 44 is an operating terminal device. 45 is a power source such as an automobile storage battery provided on the crane body; 46, 47, 48, and 49 are operation selection solenoid valves 9, 10, 1;
1, 12 solenoids 9a, 9b, 10a, 10
a crane operation selection switch that controls the current to b, 11a, 11b, 12a, and 12b; 50 is a transistor that controls the current value to the proportional solenoid relief valve 20; and 51 controls the output current of the transistor 50. potentiometer, 5
Reference numeral 2 denotes a multi-core cable that connects the crane main body, the car body side circuit 43, and the operation terminal device 44. For example, it is preferable to use a chloroprene-clad cap tire cable, and the length of the cable is determined according to the convenience of crane operation. For example, a length of 5 to 10 meters is sufficient.

The potentiometer 51 in the electric control circuit described above applies the storage battery voltage to both ends of its resistance winding, and generates a desired voltage by adjusting the position of the brush. This brush voltage is applied to the transistor 5
0 to the base electrode of the transistor and generates a large current from the emitter electrode of the transistor with an output voltage equal to the base voltage and thus the brush voltage of the potentiometer. In the illustrated example, the transistor has a voltage amplification factor of 1
It is used as a current amplifier. The hydraulic pressure at the pump outlet can be adjusted and set to a value proportional to the output voltage of the transistor (voltage and current are proportional) by means of a proportional solenoid relief valve.

Therefore, by manipulating the brush position of the potentiometer, the oil pressure at the pump discharge port can be adjusted to any desired value, and thereby the operating speed of each operation of the crane can be adjusted to any desired value.

4 and 5 show an example of an operating terminal device, which has a handle portion 53, a switch plate 54, and a potentiometer housing portion 55.
4, there are four crane operation selection switches 46, 47 corresponding to each of the four types of crane operation.
48 and 49 are arranged in one row, and the storage part 5
A speed control trigger 60 is provided on a shaft 59 of a sector gear 58 that meshes with a small gear 57 fixed on a rotating shaft 56 of a potentiometer 51 provided in the potentiometer 5, protruding from the lower side of the handle portion 53. 60 is pulled against the spring force of the spring 61 to rotate the sector gear 58 and rotate the potentiometer 51.
is connected to the sliding contact of the potentiometer 51, and a cab tire cable 52 is connected to the handle portion 53.
is inserted to connect the operating terminal device 44 to the crane main body and the vehicle body side electric circuit 43 as described above.

According to the remote control device configured as described above, an operator working at a location away from the crane main body and vehicle body holds the operating terminal device 44 in his hand and selects the operation selection switch 46, 47, 48 or 49.
After operating the trigger 60, the hydraulic The speed of the crane operation described above can be controlled by increasing the pressure of the hydraulic oil and controlling the pressure of the hydraulic oil according to the up-and-down state of the boom, the presence or absence of a load, its size, and the state of extension and contraction of the boom.

Figure 6 is a graph plotting data obtained as a result of experiments on the relationship between pump discharge port oil pressure and swing speed under various working conditions, and (A) shows boom retraction, 75°, and no load , (B) is boom retracted, horizontal;
(C) shows the boom extended, horizontal, no load; (D) shows the boom extended, horizontal, and 500Kg lifted.
Figure 7 shows the relationship between the pump discharge port oil pressure and the hoisting speed (4 lines) at various hanging loads of 0, 0.2 tons, and 0.5 tons.
This data is a plot of data obtained as a result of experiments for 1.0 tons, 1.0 tons, and 1.5 tons.

(Effects of the invention) According to the invention, crane work can be remotely controlled safely and smoothly without being practically limited by the distance from the crane, and the operator can select and speed the crane operation with just one hand. Control can be performed easily and smoothly, and therefore, economical effects can also be obtained, such as being able to perform the slinging work of a suspended load from a crane by one person.

[Brief explanation of the drawing]

Fig. 1 is a hydraulic circuit diagram of a remote control device according to the present invention, Fig. 2 is a schematic sectional view of a proportional solenoid relief valve used in the hydraulic circuit shown in Fig. 1, and Fig. 3 is a diagrammatic sectional view of a proportional solenoid relief valve used in the hydraulic circuit shown in Fig.
The figure is an electric control circuit diagram of the remote control device, FIG. 4 is a plan view of the operating terminal device, and FIG. 5 is the same as in FIG.
A cross-sectional view along the line, FIG. 6 is a graph showing the relationship between pump discharge port oil pressure and swing speed, and FIG. 7 is a graph showing the relationship between pump discharge port oil pressure and hoisting speed. DESCRIPTION OF SYMBOLS 1...Hydraulic pump, 2...Hydraulic oil tank, 3...Hydraulic oil supply pipe, 4...Hydraulic oil discharge pipe, 5...Boom hoisting cylinder, 6...Hoisting motor, 7...Boom telescopic cylinder, 8...Swivel motor, 9, 10, 11, 12
...Solenoid valve for operation selection, 19...Return bypass oil path, 20...Proportional solenoid valve, 40...Solenoid coil, 43...Crane body and vehicle body side circuit, 44...Terminal device for operation, 45...Power supply, 46,
47, 48, 49... Crane operation selection switch, 50... Transistor, 51... Potentiometer, 52... Cable.

Claims (1)

[Scope of utility model registration request] A hydraulic actuator for crane operation such as a boom hoisting cylinder, a boom telescoping cylinder, a hoisting motor, and a swing motor is connected in parallel to the hydraulic oil supply/discharge circuit connected to the hydraulic pump and hydraulic oil tank, and each oil path is used for operation selection. A solenoid valve is inserted, and a relief valve is provided in an oil passage that bypasses the discharge side to the hydraulic oil tank so as to control the discharge side hydraulic pressure of the hydraulic pump, and a relief valve is provided in an oil passage that bypasses the discharge side to the hydraulic oil tank, and controls the switching operation of the operation selection solenoid valve and the relief valve. In a remote control device for a hydraulic crane configured to remotely control a set pressure of A selection switch and a control potentiometer connected to the solenoid of the proportional solenoid relief valve are provided in the operating terminal device, and the operating terminal device 44 has a handle portion 53 that can be held with one hand, and a plurality of control potentiometers are provided. Operation selection switches 46 to 49 are disposed on the upper side of the handle part in a substantially horizontal line in a direction perpendicular to the axis of the handle part so that the switches 46 to 49 can be operated with the thumb of one hand holding the handle part 53; An operating trigger 60 of 51 is provided on the lower side of the handle so that it can be operated with the other finger of the one hand, and the operating terminal device is electrically connected to the operation selection solenoid valve and the proportional solenoid relief valve. A remote control device for a hydraulic crane, characterized in that a cable 52 for controlling the operating terminal device is drawn out from the end of the handle portion of the operating terminal device and connected to the operation selection solenoid valve and the proportional solenoid relief valve.