JP3046593B1 - Control device for lifting device - Google Patents

Abstract

Abstract: PROBLEM TO BE SOLVED: To improve the reliability of lifting / lowering and opening / closing operations of a lifting platform. SOLUTION: An elevation hydraulic cylinder 4 for rotating the parallel link and an opening / closing hydraulic cylinder 40 for opening and closing the platform, which are provided in an elevation device having a vehicle side and an elevation platform side connected by a parallel link, are controlled. In this case, the power of the power unit 50 that supplies hydraulic oil to the lifting hydraulic cylinder 4 or the opening / closing hydraulic cylinder 40 via the solenoid valves 61 and 63 and the pressure of the hydraulic piping connected to the lifting hydraulic cylinder 4 are reduced. And a first pressure switch PS1 for detecting the pressure.
In 1, the ascent / descent position in the elevating operation of the platform is detected, and the supply of hydraulic oil to the elevating hydraulic cylinder 4 is stopped.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a lifting device for lifting and lowering a lifting platform for loading and unloading cargo, etc.
The present invention relates to a control device for a lifting device that has improved reliability of opening / closing operation (preventing damage to a hydraulic cylinder for opening / closing).

[0002]

2. Description of the Related Art Conventionally, this type of lifting apparatus is mounted on the rear part of a lorry. The lifting platform is set in a horizontal state (parallel to the floor of the lorry), and a cargo or the like is placed on the platform to raise or lower the platform. In addition, loading and unloading of cargo and the like to and from a truck truck is performed. Also,
When the platform is not used, the platform is closed upright from a horizontal position.

[0003]

By the way, in an elevating device having a structure in which a parallel link mechanism is rotated by an elevating hydraulic cylinder to elevate the elevating platform, it has been conventionally known that the platform is located at an ascending limit position of the elevating operation. Since there is no function to automatically stop the power unit that detects and supplies hydraulic oil to the hydraulic cylinder for lifting, while the operator keeps pressing the lifting switch, the electric motor in the power unit idles with heavy load and wastes power. In addition to consumption, there is a problem that a load is imposed on the electric motor.

In the case of a mechanism in which the opening / closing platform is opened / closed by a hydraulic cylinder for opening / closing, when the lifting / lowering operation is performed in a state where the load of the cargo on the platform is directly applied to the hydraulic cylinder for opening / closing, the platform is opened / closed. There is a problem that an excessive force is applied to the opening / closing hydraulic cylinder which has only enough operating force to cause damage to the opening / closing hydraulic cylinder, and it is necessary to prevent such a situation beforehand.

[0005] A first object of the present invention is to solve the above problems,
An object of the present invention is to provide a control device for a lifting device, which improves the reliability of lifting and lowering operations of a lifting platform.

A second object of the present invention is to detect that the platform has reached the upper limit position of the elevating operation and automatically stop the power unit, thereby eliminating unnecessary power consumption of the battery and extending the life of the motor. It is an object of the present invention to provide a control device for a lifting device which can be realized.

A third object of the present invention is to prevent the opening and closing hydraulic cylinder for opening and closing the lifting platform from being damaged by the application of an excessive force due to the load on the platform to the opening and closing hydraulic cylinder. It is an object of the present invention to provide a control device for a lifting device.

[0008] Other objects and novel features of the present invention will be clarified in embodiments described later.

[0009]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a method for connecting a vehicle side and a lift platform side.
Parallel links, said platform horizontal state or
Support the platform with the tip of the platform lowered.
And horizontal and inclined switching stopper is rotated the parallel link
Lifting hydraulic cylinder for raising and lowering the platform
And an opening and closing hydraulic cylinder for opening and closing the platform
And the hydraulic cylinder for lifting and lowering or the hydraulic cylinder for opening and closing
To supply hydraulic oil to the
Power unit and a control electric circuit for controlling the hydraulic circuit.
In a control device for a lifting device for controlling a lifting device provided with a road , the hydraulic circuit includes a hydraulic oil of the power unit.
The delivery side hydraulic piping on the delivery side and the lifting / lowering hydraulic cylinder side
A first solenoid valve for connecting a hydraulic pipe,
Connect the piping to the hydraulic piping on the opening / closing hydraulic cylinder side.
Through a second solenoid valve and the first or second solenoid valve
The lifting hydraulic cylinder or the opening / closing hydraulic cylinder
Hydraulic oil is inserted into the hydraulic piping to return to the power unit.
A third solenoid valve, a first pressure switch for detecting the pressure of a hydraulic pipe on the hydraulic cylinder side for lifting and lowering ,
Second pressure for detecting the pressure of the hydraulic piping on the hydraulic cylinder side
And a control electric circuit , wherein the control electric circuit comprises:
When the pressure switch operates at a predetermined pressure or higher, the
Detecting the ascent limit position in the ascent / descent operation of the platform,
The power supply to the power unit is stopped, and the lifting hydraulic pressure is reduced.
The supply of hydraulic oil to the cylinder is stopped, and the second pressure switch is turned off.
Switch is above a predetermined pressure and the load on the platform is
Detecting that it is applied to the opening / closing hydraulic cylinder
In the state, disconnect the down switch at the relay contact and
Transition from platform opening / closing operation to lifting / lowering operation is prohibited.
Stops and the second pressure switch is turned off when the pressure is lower than a predetermined pressure.
The platform load is applied to the opening / closing hydraulic cylinder.
The relay connection is not detected.
Connect the down switch at the point
It is characterized in that it can be moved up and down.

[0010]

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a control device for a lifting device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a hydraulic circuit diagram according to an embodiment of the present invention, FIG. 2 is an electric circuit diagram, and FIGS. 3 to 6 show a mechanism portion of an elevating device.

First, the lifting device shown in FIGS. 3 to 6 will be described. In these figures, a rotating shaft 3 is supported by a lifting device frame 2 fixed to a chassis 1A of a lorry 1, and the rotating shaft 3 is rotated by a lifting hydraulic cylinder 4 mounted in the frame 2. It is designed to be driven. The rotating side plate 5 is fixed to both sides of the rotating shaft 3, and the base end of the main arm 6 is pivotally mounted (rotatably mounted) on the rotating side plate 5 with a pin 7. A base end of a sub arm 8 that forms a parallel link with the main arm 6 is pivotally connected to the frame 2 with a pin 9. The distal end of the main arm 6 is pivotally connected to the lower end of the vertical link body 10 with a pin 11, and the distal end of the sub arm 8 is pivotally connected to the upper end of the vertical link body 10 with a pin 12. A connecting rod 1 having a length adjusting function is provided between the main arm 6 and the rotary side plate 5.
The main arm 6 also rotates together with the rotary side plate 5 when the rotary side plate 5 rotates.

The elevating platform 20 has a vertical reinforcing member 22 fixed to the back side of an upper plate member 21. As shown in FIG. FIG.
As shown in FIGS. 5 and 6 in which the inside of the frame Q is enlarged, the mounting portion 23 includes an end surface 24 substantially perpendicular to the upper plate 21 and a bracket 25, and is fixed to the upper plate 21 and the reinforcing member 22. The bracket 25 is pivotally attached to the upper end of the vertical link body 10 by the pin 12 together with the tip of the sub arm 8.

The vertical link body 10 has a substantially triangular shape with a wide intermediate portion, and has a horizontal / inclination switching stopper 30. That is, the pivot 31 of the horizontal / inclination switching stopper 30 is rotatably mounted within a predetermined angle range near the vertex of the intermediate portion of the vertical link body 10, and the switching handle 32 is fixed to the pivot 31 of the horizontal / inclination switching stopper 30. 5 and 6, the stopper 30 can abut against the end face 24 of the mounting portion 23 in the solid line position of the handle 32.
The lifting platform 20 is moved by the vertical link body 10 in FIG.
It can be supported horizontally as indicated by the solid line. Also, handle 32
When the stopper 30 is rotated to the virtual line position, the stopper 30 is disengaged from the end surface 24 on the mounting portion side, and the tip end side of the lifting platform 20 is slightly inclined as shown by the virtual line R in FIG. Become.

An opening / closing hydraulic cylinder 40 is mounted between an intermediate portion of the vertical link body 10 and a reinforcing member 22 on the lifting platform 20 side.
By extending the zero piston rod, the lifting platform 20 can be closed upright as shown by the symbol S in FIG.

On the other hand, as shown in the hydraulic circuit diagram of FIG. 1, a lifting hydraulic cylinder 4 for driving the lifting platform 20 up and down, and a platform opening and closing the lifting platform 20 from a horizontal state to a vertical state to a closed state. Power unit 5 to supply hydraulic oil to
0 is installed on the vehicle side of the truck. The power unit 50 includes an oil tank 51, a pump 53 for sending hydraulic oil in the oil tank 51 to a hydraulic pipe 52, a motor (electric motor) 54 for driving the pump 53,
4 is provided with a power unit operating relay Mg for energizing 4 and an electromagnetic switching valve 55 for returning the operating oil of the hydraulic pipe 52 to the oil tank 51. The voltage of the battery power supply E of the lorry 1 is supplied to the motor 54 via the relay Mg.

The hydraulic pipe 52 and the hydraulic cylinder 4 for raising and lowering
Is connected through a solenoid on-off valve 61 to a hydraulic pipe 60 connected to the hydraulic pipe 60. The hydraulic pipe 52 and the hydraulic pipe 62 connected to the opening / closing hydraulic cylinder 40 are connected to the electromagnetic on-off valve 6.
3 are connected. The lifting platform 2 is provided between the solenoid on-off valve 63 and the on-off hydraulic cylinder 40.
A flow control valve 65 with a check valve at the time of opening 0 and a flow control valve 66 with a check valve at the time of closing are inserted. Further, a pressure switch P for detecting the pressure of a hydraulic pipe 60 connecting the lifting hydraulic cylinder 4 and the electromagnetic switching valve 61 is provided.
S1 is installed. The pressure switch PS1 has a normally open contact (on when the pressure is equal to or higher than a predetermined value) and has a pressure of 210 kg / c.
m ² or more, it is turned on, and the lifting platform 2
A rising limit state of 0 is detected. A hydraulic pipe 6 connecting the opening / closing hydraulic cylinder 40 and the electromagnetic opening / closing valve 63
A pressure switch PS2 is provided to detect the pressure of the second pressure. The pressure switch PS2 has a normally open contact (ON when the pressure is equal to or higher than a predetermined value), is turned on when the pressure is 3 kg / cm ² or higher, and the load of the lifting platform 20 is directly applied to the opening / closing cylinder 40. Is detected.

In the electric circuit for controlling the hydraulic circuit shown in FIG. 2, the voltage of the battery power source E of the lorry 1 is increased through a key switch KSW, a fuse FS, an up push button switch SWup, a down push button switch SWdn, and an open / close push button switch. SWoc. Pressing only the up push button switch SWup raises the elevating platform 20; pressing only the down push button switch SWdn lowers the up / down platform 20; pressing both the up push button switch SWup and the open / close push button switch SWoc raises and lowers the platform. 2
The closing operation of “0” is instructed to be an opening operation by pressing both the down push button switch SWdn and the open / close push button switch SWoc. CR1, CR2, CR3, CR
Reference numerals 4 and CR5 denote relays and their contacts, a is a solenoid (electromagnetic coil) of the electromagnetic on-off valve 61, b is a solenoid of the electromagnetic on-off valve 63, and c is a solenoid of the electromagnetic switching valve 55 in the power unit. Also, D1 to D1
2 is a diode.

Next, the operation of the above embodiment will be described. In the running state of the lorry 1 (when the lifting device is not used), the hydraulic circuit is in the state of FIG. 1, and the electric circuit of FIG.
Is in the off state, the hydraulic cylinder 4 for elevating and lowering extends the most and pivots the main arm 6 to the ascending limit position, and the hydraulic cylinder 40 for opening and closing also extends most and the lifting platform 20 Rotate to the vertical state as
The rear opening of the bed 1B of the truck 1 is closed.

When the vehicle is stopped, the key switch K
After turning on the SW, if both the down push button switch SWdn and the open / close push button switch SWoc are pressed (on),
The electromagnetic on-off valve 63 in the hydraulic path of the on-off hydraulic cylinder 40 is opened, and the electromagnetic switching valve 55 in the power unit 50 is opened.
, The hydraulic oil in the opening / closing hydraulic cylinder 40 is returned to the oil tank 51 in the power unit 50, and the elevating platform 20 is gradually opened horizontally from a vertically closed state. At this time, the horizontal / inclination switching stopper 3 on the vertical link body 10 side is used.
0 abuts on the end surface 24 of the mounting portion 23 of the lifting platform 20 (when the platform is set horizontally) or until the side edge of the vertical link body 10 abuts on the end surface 24 (when setting the inclination of the platform: R in FIG. 3). Position) The opening / closing hydraulic cylinder 40 is contracted.

As described above, if the end surface 24 of the mounting portion 23 on the lifting platform 20 side is supported by the vertical link body 10 side, the opening / closing hydraulic cylinder 40 and the electromagnetic switching valve 63
The pressure of the hydraulic piping 62 between them is sufficiently less than 3 kg / cm ² ,
The pressure switch PS2 is turned off. As a result, the relay CR3 is in the excited state, and by pressing the down push button switch SWdn, the electromagnetic switching valve 61 of the hydraulic path of the lifting hydraulic cylinder 4 is opened and the electromagnetic switching valve 55 in the power unit 50 is opened. The hydraulic oil in the lifting hydraulic cylinder 4 is opened and the oil tank 51 in the power unit 50 is opened.
To the lowering operation of the lifting platform 20,
By holding down the down push button switch SWdn, the lifting platform 20 can be landed.

The mounting portion 2 on the lifting platform 20 side
3 is not supported on the vertical link body 10 side (for example, although the horizontal / inclination switching stopper 30 is set so that the platform is not in contact with the end surface 24 of the mounting portion 23 on the vertical platform 20 side, the vertical platform is set. 2
When the platform is insufficiently opened, for example, when 0 is opened horizontally, the pressure of the hydraulic pipe 62 between the opening / closing hydraulic cylinder 40 and the solenoid on-off valve 63 becomes 3 kg / cm ² or more,
The pressure switch PS2 is turned on, the relay CR5 is excited, and the normally closed contact of CR5 is opened.
Is in the non-excited state, the electromagnetic open / close valve 61 of the hydraulic path of the lifting hydraulic cylinder 4 cannot be opened even if the downward push button switch SWdn is pressed, and the lowering operation of the lifting platform 20 cannot be shifted. This makes it possible to prevent the accident that the opening / closing hydraulic cylinder 40 is damaged by performing the lifting / lowering operation while the load of the load on the lifting platform 20 is applied to the piston rod of the opening / closing hydraulic cylinder 40.

When the lifting push button switch SWup is pressed from the landing state of the lifting platform 20, the relay Mg in the power unit 50 is excited, and the electromagnetic switching valve 61 of the hydraulic path of the lifting hydraulic cylinder 4 is opened. By supplying the hydraulic oil from the power unit 50 to the cylinder 4, the lifting platform 20 can be raised to the ascending limit position corresponding to the floor height of the carrier 1B. Such a lifting operation between the height of the platform of the lifting platform 20 and the ground makes it possible to execute cargo loading.

After reaching the ascending position of the lifting platform 20, the pressure switch PS1 becomes 210 kg / cm ² or more and changes to the ON state, the relay CR2 is turned ON, and C
When the normally closed contact of R2 opens, the relay Mg in the power unit 50 is turned off, and the operation of the power unit 50 stops. As a result, power loss when the operation of the motor 54 in the power unit 50 is continued can be eliminated, and damage to the motor 54 can be avoided. In addition, damage to the loading platform caused by the lifting platform 20 being continuously pressed against the loading platform 1B can be reduced.

After reaching the ascending position of the lifting platform 20, if both the push-up switch SWup and the open / close push-button switch SWoc are pressed, both the relay CR1 and the relay CR2 are excited.
Operates, the electromagnetic on-off valve 63 in the hydraulic path of the opening / closing hydraulic cylinder 40 opens, hydraulic fluid is supplied to the opening / closing hydraulic cylinder 40, and the elevating platform 20 is in a vertically upright closed state (reference S in FIG. 3). Becomes

The hydraulic circuit including the power unit 50 and the control electric circuit can be appropriately modified as long as the required operation of the lifting platform 20 can be realized.

Although the embodiments of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited to the embodiments and various modifications and changes can be made within the scope of the claims. There will be.

[0029]

As described above, the control device for a lifting device according to the present invention comprises: a power unit for supplying hydraulic oil to a lifting hydraulic cylinder or an opening / closing hydraulic cylinder via an electromagnetic valve; And a first pressure switch for detecting a pressure of a hydraulic pipe connected to the hydraulic cylinder. Supply of hydraulic oil to the power unit can be stopped, wasteful operation of the power unit can be avoided, power consumption of the on-board battery can be reduced, motor idling in the power unit can be prevented, and the life of the power unit can be extended.

Further, since the second pressure switch for detecting the pressure of the hydraulic pipe connected to the opening / closing hydraulic cylinder is provided, it is detected that the load of the platform is applied to the opening / closing hydraulic cylinder. In the state where
The transition from the opening / closing operation of the platform to the lifting / lowering operation can be prohibited, and it is possible to prevent the piston rod of the opening / closing hydraulic cylinder from being damaged due to excessive force being applied.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit in an embodiment of a control device for a lifting device according to the present invention.

FIG. 2 is a circuit diagram of a control electric circuit of a hydraulic circuit.

FIG. 3 is a side view of the lifting device.

FIG. 4 is a front view of the lift device with the lift platform closed.

FIG. 5 is an enlarged side view showing a vertical link body of the lifting device, a lifting platform (in a closed state), and a mounting portion of an opening / closing hydraulic cylinder.

FIG. 6 is an enlarged front view of the same.

[Explanation of symbols]

DESCRIPTION OF REFERENCE NUMERALS 1 lorry 1A chassis 1B carrier 2 frame 3 rotating shaft 4 lifting hydraulic cylinder 5 rotating side plate 6 main arm 8 sub arm 10 vertical link body 20 lifting platform 30 horizontal / tilt switching stopper 32 handle 40 opening / closing hydraulic cylinder 50 power unit 51 oil tank 53 Pump 54 Motor 55 Solenoid selector valve 61, 63 Solenoid on / off valve CR1, CR2, CR3, CR4, CR5, Mg Relay PS1, PS2 Pressure switch SWup Up push button switch SWdn Down push button switch SWoc Open / close push button switch

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60P 1/44

Claims (1)

(57) [Claims] (1 ) The distance between a vehicle side and a lifting platform (20) side is defined.
Parallel links to connect and the platform in horizontal state
Or, support the platform with the tip of the platform lowered.
A horizontal / tilt switching stopper (30), a hydraulic cylinder (4) for lifting and lowering the platform by rotating the parallel link, a hydraulic cylinder (40) for opening and closing the platform, and a hydraulic cylinder (40) for opening and closing the platform . Hydraulic cylinder or open
Operates via hydraulic circuit including solenoid valve in closing hydraulic cylinder
The power unit (50) for supplying oil and the hydraulic circuit are controlled
In the lift device control device for controlling the lift device including a control electric circuit for controlling the hydraulic circuit, the hydraulic circuit is configured to transmit hydraulic fluid of the power unit (50).
Hydraulic pipe (52) and the hydraulic cylinder for lifting
A first solenoid valve for connecting to a hydraulic pipe (60);
The hydraulic piping (52) and the hydraulic piping (6
2), a second solenoid valve connecting the first solenoid valve and the first or second solenoid valve.
The lifting hydraulic cylinder or the opening / closing oil via a magnetic valve
Hydraulic system for returning hydraulic oil from the pressure cylinder to the power unit
A third solenoid valve inserted into the pipe, a first pressure switch (PS1) for detecting the pressure of a hydraulic pipe (60) on the lifting hydraulic cylinder side, and a hydraulic pipe (62) on the opening / closing hydraulic cylinder side. )
A second pressure switch (PS2) for detecting the pressure of the first pressure switch.
The platform moves up and down by operating above the pressure
The ascent of the power unit is detected and the power unit
To stop the power supply to the hydraulic cylinder
The supply is stopped, and the second pressure switch is turned on when the pressure exceeds a predetermined pressure.
Home load is applied to the opening / closing hydraulic cylinder
That the relay (CR3) contacts
Open / close operation of the platform by disconnecting the down switch
From the second pressure switch to the second pressure switch.
The platform load is lower than the predetermined pressure.
Detected that it has not been applied to the closing hydraulic cylinder
In the state, the contact of the relay (CR3) makes the down switch
A lifting and lowering device control device, wherein the lifting and lowering operation of the platform is enabled .