JPS5930363B2 - Work equipment lifting control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for lifting and lowering a working machine such as a tractor. The working machine is raised and lowered, and when lowered, the working machine is automatically stopped at the hydraulic control lever position.

A tractor is equipped with a hydraulic system for lifting and lowering the work equipment at the rear of the machine, and the hydraulic system is used to raise and lower the work equipment. Conventionally, the position control valve is operated using a hydraulic control lever, and the switching operation of the position control valve is controlled by the hydraulic control lever. Since the hydraulic system is controlled through the The disadvantage is that the control lever must be operated to the up position to raise the working machine, and then the transmission lever must be operated to the reverse position, making operation extremely complicated.

Moreover, if the hydraulic control lever is operated each time in this way, there is also the disadvantage that when the hydraulic control lever is returned to the lowered position, the set position changes and the plowing depth varies.

The present invention has solved these conventional problems, and its features include a control lever for setting the lifting and lowering position of the work equipment, a feedback mechanism linked to the lifting and lowering of the work equipment, and a hydraulic pump. A position control valve is provided between the hydraulic system for lifting and lowering the work equipment, and the position control valve includes an unload valve that returns hydraulic fluid from the hydraulic pump, a control lever,
a biloft valve that controls the unload valve in such a way as to close the unload valve during a lifting operation and open the unload valve in conjunction with a feedback mechanism when the work equipment is raised to a control lever setting position; , a work equipment elevation control device including a check valve that returns hydraulic fluid from a hydraulic system when a control lever is lowered and closes in conjunction with a feedbank mechanism when the work equipment is lowered to a control lever setting position;
Separately from the control lever, a switch for raising and lowering the work equipment is provided, and a solenoid valve for raising, which closes when the switch commands to raise, is connected in series with the unloading valve, so that it closes when the switch commands to raise and opens when commanding to lower. The point is that a solenoid valve is connected in series with a check valve.

Hereinafter, the present invention will be described in detail with reference to the illustrated embodiments.
In the figure, 1 is a tractor body, which has front wheels 2 and rear wheels 3.

4 is the engine, 5 is the hood, 6 is the instrument panel, 7 is the steering wheel, and 8 is the driver's seat.

Reference numeral 9 denotes a hydraulic system for lifting and lowering a working machine, which is mounted on the rear part of the tractor body 1 and has a pair of lift arms 10.

Reference numeral 11 denotes a rotary device, which is attached to the rear of the tractor body 1 via a three-point linkage mechanism 12 and can be raised and lowered by a lift arm 10 of a hydraulic device 9 via a lift rod 13.

14 is a push button switch for raising and lowering the working machine, and is attached to the instrument panel 6.

FIG. 2 shows the hydraulic system of the hydraulic device 9, and 32 shows the hydraulic system of the hydraulic device 9.
A position control valve that controls the position of a pilot valve 15.
, an unload valve 16, and check valves 17 and 18, the pilot 15 of which is operatively connected to the interlocking rod 19, and the reed check valve 11 is operatively connected to the interlocking rod 19.

Both ends of the interlocking rod 19 are connected to a hydraulic control lever 22 and a feedback lever 23 that rotate around a support shaft 20.21, and the feedback lever 23 is connected to a hydraulic arm 25 of the hydraulic device 9 via a feedbank rod 24. connected.

26 is a hydraulic pump, and 27 is a relief valve.

28 is a solenoid valve for ascending, and 29 is a solenoid valve for descending. These solenoid valves 28 and 29 are both normally open types, and are connected in series to the unload valve 16 and check valve 11, respectively.

Reference numeral 30 denotes a limit switch for detecting the lifting of the working machine, which is operated by the lift arm 10.

Next, the operation of the above configuration will be explained with reference to the electrical circuit diagram shown in FIG.

Normally, the solenoid valves 28 and 29 are in the open state, and when the hydraulic control lever 22 is operated from the solid line position to the two-dot chain line position, the spool of the pilot valve 15 slides in the direction of arrow C via the interlocking rod 19. Byront pressure is applied to the unload valve 16, and the unload valve 16 closes.

Therefore, the hydraulic oil from the hydraulic pump 26 is transferred to the position control valve 3.
2 to the hydraulic device 9, which operates in the upward direction and lifts the rotary device 11 with the lift arm 10.

When the hydraulic device 9 operates in the upward direction, the feedback rod 24 is pressed in the direction of arrow b, and the feedback lever 2
The counterclockwise rotation of 3 pulls back the spool of the pilot valve 15 in the direction of arrow C via the interlocking rod 19, so the unload valve 16 opens and the hydraulic device 9 closes to the rotary device 1.
Stop with 1 lifted.

When the hydraulic control lever 22 is returned to the solid line position from this raised state, the feedback lever 23 has already been rotated counterclockwise, so the spool of the check valve 17 slides in the direction of the arrow d via the interlocking rod 19. the check valve 1
7 is opened, and the hydraulic oil in the hydraulic system 9 flows through the check valves 11 and 7.
It is returned via the electromagnetic valve 29, the hydraulic device 9 operates in the downward direction, and the rotary device 11 descends.

When lifting the a-tally device 11 when reversing the tractor, etc., the hydraulic control lever 22 is held at its set position and the push button switch 1 provided on the instrument panel 6 is pressed.
Press 4 to issue a climb command.

Then, the relay (51-R□, which is an abbreviation of R1 at address 51, and the same shall apply hereinafter) in the electric circuit shown in Figure 3 is energized,
Since the a contact 52-R is turned on, the relay 52-R3 is energized, the a contacts 53-R3, 55-R3 and 56-R3 are turned on, and both the solenoid valves 28 and 29 are closed.

Therefore, hydraulic oil from the hydraulic pump 26 is supplied to the hydraulic device 9, and the a-tally device 11 is raised as described above.

At this time, if the hydraulic control lever 22 remains in the lowered position, when the hydraulic device 9 moves upward, the feedback rod 24
The upward movement of the hydraulic device 9 is fed back to the interlocking rod 19 via the feedback lever 23, and the spool of the check valve 17 slides in the direction of arrow d, opening the check valve 17. Since the connected electromagnetic valve 29 is in the closed state, the hydraulic device 9 continues its upward movement.

When the rotary device 11 rises to the upper limit due to the operation of the hydraulic device 9, the limit switch 30 is turned on, the relay 54-R2 is energized, and the b contact 55-R2 is turned off, so the solenoid valve 28 is opened and the hydraulic device 9 stops the rise.

At the same time, the a contact 57-R2 turns on, but the a contact 57-R
1 is off and Rin-57-R is not excited, so
By turning on the b contact 52-R4, the relay 52-R3 maintains the excited state, and the solenoid valve 29 remains closed.

When the tractor completes reversing, etc., and presses the push button switch 14 to issue a descending command, ! JL'-51-R.

is excited, and the a contacts 52-R1 and 57-R1 are turned on.

At this time, since the a contact 57-R2 is in the on state as described above, ') V-57-R is excited, and the b contact 52-R4
is turned off, V-52-R3 is demagnetized, and the a contact 56
-R3 is turned off, so the solenoid valve 29 is opened.

When the solenoid valve 29 is opened, the check valve 17 is in the open state as described above, so the hydraulic oil in the hydraulic device 9 is released through the check valve 17 and the solenoid valve 29, and the hydraulic device 9 is opened. Operating in the downward direction, the rotary device 11 descends.

At this time as well, the downward movement of the hydraulic device 9 is caused by the feedback rod 2.
4. Feedback is sent to the check valve 17 via the feed bank lever 23 and the interlocking rod 19, so the check valve 17 closes at the position set by the hydraulic control lever 22, and the hydraulic device 9 moves downward at that position. stop.

The reed rotary device 11 returns to the position before being raised.

As described in detail in the embodiments above, in the present invention, a rising solenoid valve is connected in series to the answer valve, and a descending solenoid valve is connected in series to the check valve, and these solenoid valves are operated by a rising command and a descending command from a switch. Therefore, when necessary, the hydraulic control lever system can be left as it is and the working machine can be raised or lowered by switch operation, making Q-operation very easy when the tractor moves backward or turns.

It is also equipped with a control lever for setting the lifting and lowering position of the work equipment, a feed bank mechanism that is linked to the lifting and lowering of the work equipment, and a position control valve interposed between the hydraulic pump and the hydraulic device for lifting and lowering the work equipment. The control valve consists of an unload valve that returns hydraulic oil from the hydraulic pump, and an unload valve that closes when the control lever is raised and operates in conjunction with the feed bank mechanism when the work equipment has risen to the control lever set position. Check the pilot valve that controls the unload valve to open, return the hydraulic oil from the hydraulic system when the control lever is lowered, and close it in conjunction with the feed bank mechanism when the work equipment descends to the control lever set position. including valves,
A solenoid valve is connected in series to the unloading valve and the lowering check valve, and each solenoid valve is controlled to open and close using a switch, and when the work equipment is lowered, the switch is only operated, and the control lever is not operated. The working machine always returns to the position before being raised, so positional fluctuations and accompanying changes in plowing depth Q can be prevented, and stable work can be performed.

In addition, it is only necessary to add a solenoid valve and a switch to a conventional control device with a position control function, so the conventional control device can be used as is, and it can be very easily adopted for conventional control devices. Can be done.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, with FIG. 1 being an overall side view, FIG. 2 being a circuit diagram of the hydraulic system, and FIG. 3 being a circuit diagram of the electrical system. 1... Tractor body, 9... Hydraulic system, 14...
Push button switch, 15...Pilot valve, 16...Unload valve, 17...Check valve, 22...Hydraulic pressure control lever, 28...Solenoid valve for ascending, 29...Solenoid valve for descending , 32...Position control valve.

Claims (1)

[Claims] 1 Equipped with a control lever for setting the lifting and lowering position of the work equipment, a feed bank mechanism linked to the lifting and lowering of the work equipment, and a position control valve interposed between the hydraulic pump and the hydraulic device for lifting and lowering the work equipment, The control valve consists of an unload valve that returns the hydraulic oil from the hydraulic pump, and an unload valve that closes the unload valve when the control lever is raised and unloads in conjunction with the feed bank mechanism when the work equipment has risen to the control lever set position. Check the pilot valve that controls the unload valve to open the valve, return the hydraulic oil from the hydraulic system when the control lever is lowered, and close it in conjunction with the feedback mechanism when the work equipment descends to the control lever set position. In a work equipment lift control device including a valve, a switch for commanding the work equipment to go up and down is provided separately from the control lever, and a solenoid valve for raising that closes when the switch commands a raise is connected in series with an unloading valve, and the lift command of the switch is A work machine elevation control device characterized in that a descending solenoid valve that closes when commanded and opens when descending command is connected in series with a check valve.