JPH0276504A - Lift controller for ground operating machine - Google Patents

Abstract

PURPOSE:To prevent accidental movement by locking the machine so as not to be driven to rise upward, even when the switch is operated upward, once the actual height is detected higher than the upper limit position. CONSTITUTION:At start, the actual height of the machine by the lift sensor 15 is compared with the lifting limit of the setter 20 in the computing unit 21 and judged in the unit 27 whether the lifting movement of the machine should be locked or not, and only in the case when locking is needed, the lifting movement of the machine is locked. This locked state is automatically unlocked by detecting the relationship between the actual height of the machine by the operation of the switch 18 and the lifting limit position, thus it is not troublesome for the operator. Thus, wrong operation can be detected and locking can be done, when needed, and there is no troubles that the lock must be released, every time when the engine is started.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a land-based work machine (hereinafter simply referred to as a working vehicle) such as a low tiller that is attached to the rear of a traveling vehicle such as a tractor (hereinafter simply referred to as a vehicle). The present invention relates to a lifting control device for a working machine (referred to as a machine), and particularly to a lifting control device for a working machine that prevents the working machine from unexpectedly descending when the engine is started.

(Prior Art) In general, the above-mentioned lifting control device for work equipment has an automatic control function that controls the height position of the work equipment to follow a preset lifting target value, and a height position control function that controls the height position of the work equipment to follow a preset lifting target value. Equipped with manual control function to adjust.

In a work machine having such a control function, if the automatic control function is selected when starting the engine, if the engine is started in this state, depending on the positional relationship between the lifting target value and the current height of the work machine, Unexpected lowering movements may occur.

As a technology to prevent the above unexpected operation,
A ground-based work machine as shown in Japanese Patent No. 8-26928 has been proposed.

The work machine is provided with a lock mechanism that disables the work machine from moving up and down when either the automatic control function is selected or the engine rotational speed is below a predetermined value. Then, when the automatic control function is selected, the engine rotational speed is in an operating state higher than the scheduled value, and the lift operation means is manually operated and a lift command is issued, the lock mechanism is released. Then, the work equipment can be raised and lowered.

(Problem to be solved by the invention) The above-mentioned conventional technology has the following problems.

In other words, with conventional work equipment, there is a lock mechanism that disables the work equipment even when it is considered unlikely to cause unexpected movement based on the positional relationship between the target elevation value of the work equipment and the current height position. Therefore, there is a problem in that an operation procedure must be performed to release this locking mechanism at the start of the lifting/lowering operation. In addition, the unlocking is performed manually, and there is a problem in that it is troublesome for the operator.

An object of the present invention is to solve the above-mentioned problems and to provide a lifting control device for a ground-based working machine that has a control function that automatically activates and automatically releases a locking mechanism that disables lifting of the working machine. It is about providing.

(Means and effects for solving the problem) In order to solve the above problems, the present invention detects the positional relationship of the current height of the work machine with respect to the ascent limit position of the work machine when the engine is started. means, and when the detection means detects that the current height is higher than the raising limit position, a locked state is formed in which the working machine is not driven to rise or fall even if the lift operation switch is operated to the rise side. and a means for releasing the locked state by operating the operating switch to the lowering side and lowering the working machine below the upper limit position.

In the present invention having the above configuration, when the engine is started, the current height of the work equipment is first compared with the ascent limit position, and it is determined whether or not it is necessary to form a lock state that disables the work equipment's vertical movement. A judgment is made. Therefore, a locked state is formed only when necessary, making it impossible to raise and lower the working machine. In addition, the locked state of the lifting operation can be determined automatically by detecting the relationship between the current height position and the lifting limit position of the work equipment and according to the detection result, so that the operator does not have to bother. Nor.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 8 is a side view of the traveling working vehicle of the present invention, and FIG. 9 is a perspective view showing the main parts of the working machine and the coupling mechanism section connected to the rear part of the traveling working vehicle.

In the figure, a working machine 3 such as a tillage rotor is connected to a vehicle 1 via a connecting mechanism 2.

The work machine 3 is connected to the vehicle 1 via a three-point lifting link mechanism consisting of a top link 4 and a pair of left and right lower links 5 and 6. Further, a hydraulic actuator 7 and lift arms 8 and 9 driven by the actuator tough are attached to the vehicle 1 side.

Lower links 5.6 and lift rods 10.1 respectively
When the hydraulic actuator 7 expands and contracts, the lift arms 8 and 9 swing, and the working machine 3 moves up and down.

A horizontal sensor 12 is provided on the vehicle 1, and a lift rod 1
1 is provided with a hydraulic actuator 13 that expands and contracts the rod 11 and a stroke sensor 14 that detects the amount of expansion and contraction of the lift rod 11.

Then, the stroke sensor 14 monitors the amount of expansion and contraction according to the degree of inclination of the vehicle 1 detected by the horizontal sensor 12 so that the work equipment 3 is held horizontally with respect to the ground even if the vehicle 1 rolls. At the same time, the hydraulic actuator 13 can be driven and controlled.

The lift arms 8 and 9 are provided with a foot sensor 15, which is constituted by a rotary potentiometer that detects the lift angle thereof, and the lifting and lowering of the working machine 3 can be controlled in accordance with the sensor output.

On the other hand, on the working machine 3 side, a pillar 16 is provided which traces the ground and whose opening degree θ changes depending on the depth of tillage when the working machine 3 is in the working position. The opening degree θ of the pillar 16 is detected via a rod 17A by a pillar sensor (angle sensor) 18A composed of a rotary potentiometer, and according to the sensor output, the hydraulic actuator 7 is driven to set the tilling depth. It is possible to control the plowing depth by keeping it at a certain value.

The vehicle 1 is provided with an operator's seat 17, and an operation switch 18 for manually controlling the raising and lowering of the working machine 3 is provided next to the seat.

−7= of the working machine 3 depending on the position of the operation switch 18 The operation will be explained with reference to FIGS. 5 and 6.

FIG. 5 is a diagram showing the contact configuration of the operation switch 18, FIG. 6(a) is a front view of the conductive slide member, and FIG. 6(b) is a side view of the same. In the same figure, the operation switch 18 can be tilted about the axis 34 and can be operated to positions A, B, C, D, and N. The lever positions of the operation switch 18 when moved to the A, B, C, D and N positions are - dotted chain lines 18a, 18b, 18c, 18ds 18
It is indicated by n.

The contact portion 28 of the operation switch 18 includes three contact members 30 and 31 that are electrically insulated and arranged separately.
．． 32, a conductive slide member 29 that is provided at the lower end of the operation switch 18' and slides linearly on the contact member in the direction of arrow 51, and is always in contact with the stud portion 29a of the slide member 29. , and a common contact member 33.

The slide member 29 is provided on a slide block 52 having electrical insulation properties, and includes conductive stud members 29 as 29 bs 29 c exposed on the surface of the slide block 52 and the slide block 52. embedded in the stud members 29a, 2.
The lead wires 29d and 29e electrically connect the 9bs 29c.

The slide block 52 is configured such that the protrusion 53 of the operation switch 18 is engaged with a recessed portion on the back surface thereof, and when the operation switch 18 is tilted about the central axis 34, it is guided by a guide member (not shown). Slide linearly in the direction of arrow 51.

The dogleg-shaped portion at the bottom of FIG. 5 indicates the position of the lead wire of the slide member 29 corresponding to the operating position of the operating switch 18.

When the operation switch 18 is tilted to the A position, the first contact portion 30 and the common contact member 33 are connected by the slide member 29. When the operation switch 18 is in the B position, the first contact member 30, the third contact member 32, and the common contact member 3
3 is connected.

When the operation switch 18 is in the N position, the third contact member 32 and
The common contact member 33 is connected, the second contact member 31 and the third contact member 32 are connected to the common contact member 33 at the C position, and the second contact member 31 and the common contact member 33 are connected at the D position. is connected.

In this way, A-D and neutral The contact structure is such that five operation areas at point N can be selected.

Further, the operating switch 18 is configured to return to the N position when the operator's hand is released from each of the A, B, C, and D positions.

Depending on the operating position of the operating switch 18, the working machine 3 operates as follows.

The working machine 3 is not raised or lowered when the operation switch 18 is in the N position, lowered in the A and B positions, and raised in the C and D positions. No matter which position the operation switch 18 is moved,
When the operator releases the switch 18, it returns to the N position.

Incidentally, in the A and D positions, the lifting and lowering of the work implement 3 does not stop even if the switch 18 returns to N. That is, once the operating switch 18 is operated to the A position, the work implement 3 descends to the lower limit value, and when the operation switch 18 is operated to the D position, it rises to the upper limit value and then stops.

When the operation switch 18 is moved to positions B and C, the work implement 3 is lowered or raised as long as the operation switch 18 remains at the position.

An example of a control device for extending and retracting the hydraulic actuator 7 in response to a signal output according to the operating position of the above-mentioned operating switch 18 and a detection signal of the lift sensor 15 will be shown below.

FIG. 1 is a block diagram of such a control device.

In the same figure, the work equipment 3 detected by the lift sensor 15
The current height position (current lift value) is determined by the lift deviation calculation unit 2.
1 and is input to the downward deviation calculation section 23.

The ascent deviation calculation unit 21 detects the deviation of the current lift value from the ascent limit position data of the working machine 3 set in the ascent limit value setter 20, and the magnitude of both data.

On the other hand, in the descending deviation calculation section 23, the descending limit value setting device 22
The deviation of the current lift value from the descending limit position data of the working machine 3 set in , and the magnitude of both data are detected.

The upper limit value setter 20 and the lower limit value setter 22
The setting value is set by operating a setting knob (not shown).

The deviation is read into the lift change amount setting section 35, and the deviation is used to control the lowering valve 2 that expands and contracts the hydraulic actuator 7.
6 and the lift valve 27 to determine the on-time duty ratio (hereinafter simply referred to as on-time).

The descending valve 26 and the ascending valve 27 are opened and closed according to scheduled on and off times within a preset period. If the ON time of the valves 26 and 27 within the cycle is short, the valves 26 and 27 operate intermittently, and the average lifting speed of the work implement 3 becomes slow.

On the other hand, when the on time is long, the valves 26 and 27
The work machine 3 operates almost continuously, and the average lifting/lowering speed of the working machine 3 becomes faster. When the on time reaches its maximum, continuous lifting and lowering operation will occur.
The lifting speed of the working machine 3 becomes maximum.

The on time corresponding to the lift change amount is stored in the calculation table of the on time duty ratio storage section 24. Examples of calculation tables are discussed below with respect to FIG.

In the A position judgment section 36, (lowering limit value - current lift value)
Based on the positive and negative signs of the calculation result, it is determined whether the work implement 3 is located above or below the lowering limit position.

In the B position judgment section 37, (ascent limit value - lift limit value)
Based on the positive and negative signs of the calculation result, it is determined whether the work implement 3 is located above or below the ascent limit position.

According to the judgments of the position judgment sections 36 and 37, the on-time for lowering or the on-time for ascending according to the lift change amount is read from the on-time duty ratio storage section 24 into the valve selection drive section 25. The valve selection drive unit 25 opens and closes the ascending valve 27 and the descending valve 26 in accordance with the read on time, and causes the hydraulic actuator 7 to expand and contract.

The engine rotation detection section 34 detects whether or not the engine is rotating.

Data indicating the operation position of the operation switch 18, detection data of the engine rotation detection section 34, and data of the judgment result of the B position judgment section 37 are input to the lowering protection section 38, and based on the data, the lift change amount is determined. From the “0” storage unit 39 to the on-time duty ratio storage unit 24, the lift change amount “
0" is input.

Lift change amount “0” from the lift change amount “0” storage unit 39
is input as data to the on-time duty ratio storage section 24, and the on-time based on the data is output to the valve selection drive section 25. The lift change amount "0" becomes effective in priority to the lift change amount set in the lift change amount setting section 35 based on the upward deviation.

As a result, the ascending valve 27 and the descending valve 26 are driven according to the valve-on time based on the lift change amount "0". That is, when the lift change amount is "0", the on time is "O" and the work implement 3 is not raised or lowered.

Even when the operation switch 18 is moved to the neutral position N,
The lift change amount “0” is stored in the on-time duty ratio storage unit 24.
The data in the memory 39 is manually input, and the working machine 3 does not move up or down.

FIG. 7 shows an example of a calculation table showing the relationship between the on-time and the amount of change in lift. A calculation table based on the relationship diagram is stored in the on-time duty ratio storage section 24. In the figure, the horizontal axis is the amount of change in lift, and the vertical axis is the on-time.

The relationship between the on time and the lift change amount is shown by a curve S. When the lift change amount is larger than the dead zone P, the valve 26, 27 is turned on for the on time that corresponds to the relationship of the lift change amount and the corresponding curve S. It is operated on.

The on time increases until the lift change amount reaches M.
The valves 26 and 27 are intermittently turned on according to the on time, and when the lift change amount is M or more, the valves 26 and 27 are turned on intermittently according to the on time.
The on-operations of 27 and 27 are continuous.

Once the on-time is determined according to the calculation table shown in the figure, the deviation from the rising or falling limit value (=
When the lift change amount) is large, the proportion of time that the hydraulic actuator 7 is driven becomes large, and the lifting speed of the work implement 3 becomes faster. When the amount of change in lift is small, the proportion of time during which the hydraulic actuator 7 is driven becomes small, and the lifting speed of the working machine 3 becomes slow.

Therefore, when the deviation becomes smaller and the position of the work equipment 3 approaches the raising or lowering limit value, the raising or lowering speed of the work equipment 3 becomes slower, and shocks and overruns occur when the work equipment 3 stops. It can be prevented.

Although the calculation table shown in FIG. 7 is prepared for ascending and descending purposes and stored in the storage unit 24, the same table may be used for both ascending and descending purposes.

Next, the control flow of this embodiment will be explained in detail with reference to the flowchart of FIG.

In the flow described below, no matter which position of the operation switch 18 is moved from A to D, the flow when the switch 18 is operated to the neutral position N is first executed, and then the operation switch 18 is moved to each position of the switch 18. The corresponding operations are configured to be performed.

First, in step S1, the ascending limit value and descending limit value of the working machine 3 are converted into values corresponding to the lift sensor.

In step S2, the lift sensor 1
The difference (rise deviation) from the current lift value detected in step 5 is calculated. - In step S3, the difference (descent deviation) between the lowering limit value and the current lift value detected by the lift sensor 15 is calculated.

In step S4, it is determined whether or not the ascent limit value is greater than the current lift position. If the determination is affirmative, the process proceeds to step S5, where the ascent position flag is set to "1". If the determination in step S4 is negative, the process moves to step S6 and the ascending position flag is set to "0".

In step S7, it is determined whether the lowering limit value is greater than the current lift value, and if the determination is affirmative, the process proceeds to step S8, where the lowering position flag is set to "1". If the determination in step S7 is negative, the process moves to step S9 and the descending position flag is set to "0".

Through the above processing, the position of the working machine 3 with respect to the above-mentioned upward limit value or downward limit value can be determined based on the state of the upward position flag or downward position flag.

In other words, when the work equipment 3 is located above the upper limit value, both the upper position flag and the lower position flag are set to "
0", and when the work equipment 3 is located below the lower limit position, both the up position flag and the lower position flag are "1". Also, when the work equipment 3 is located at the lower limit position If it is located between the limit position, the ascending position flag is "1" and the descending position flag is "0".

Depending on the operating position of the operating switch 18, the working machine 3 is controlled to move up and down as follows.

First, the flow when the operation switch 18 is in the neutral position N will be explained.

When the operation switch 18 is in the neutral position N, it is determined whether the operation switch 18 is in the position C (step 51).
0) and whether or not the operation switch 18 is in position B (step 511) are both negative, and the process proceeds to step 512.

In step S12, the fine adjustment down flag is set to "0".

In step S13, it is determined whether the working machine 3 is ascending or descending. Since the operating switch 18 is in the neutral state, the determination in step S13 is negative, and the process proceeds to step S14, where the stop flag is reset.

In step S15, the value "0" is set in the lift change amount setting section 35.
” is stored.

In step S16, in order to determine whether or not the operation switch 18 is located at the D position, the rise flag is determined. When the operation switch 18 is in the N position, the rise flag is "0".

In step S17, the position of the operation switch 18 is D.
The determination as to whether or not this is the case is determined to be negative, and the process proceeds to step 818.

In step 818, in order to determine whether the operating switch 18 is located at position A, the lowering flag is determined. When the operation switch 18 is in the N position, the lowering flag is "0#".

In step S19, the position of the operation switch 18 is A.
The determination as to whether or not this is the case is determined to be negative, and the process proceeds to step S19.

In step S25, a downward protection process is performed according to a flow described later.

In step 82B, the on-times of the descending valve 26 and the ascending valve 27 are calculated. Since the lift change amount is set to "0" in step S15, the ON time is "0" according to the calculation table shown in FIG.

Therefore, when the operation switch 18 is in the neutral position N, the work implement 3 is not raised or lowered.

As explained above, when the operation switch 18 is in the N position, the lift change amount setting section 35 is set to the lift change amount "0", so the valve on time becomes "0" and the lift valve 27 and None of the lowering valves 26 are turned on, and the work implement 3 is maintained at its current height.

When the operation switch 18 is switched from the N position to the A position, in the first cycle of processing, step SIO
The judgments and operations from 818 to 818 are performed in the same way as when the operation switch 18 is in the N position.

The judgment in step S19 is affirmative, and step S20
Proceed to. In step S20, the descending flag is set and the ascending flag is cleared.

In step S21, the downward deviation is stored in the lift change amount setting section 35.

In step S22, the state of the lowered position flag is checked to determine the position of the working machine 3.

If the lower position flag is "1", the process advances to step S23, and the rising valve flag is set to "1"; if the lower position flag is "0", the process advances to step S24, where the rising valve flag is set to "0". is set. Depending on the state of the ascending valve flag, it is determined which of the ascending valve and descending valve the on-time is to be calculated.

In other words, the descending flag position "1" indicates that the work equipment 3 is below the descending limit position indicated by the descending limit value, so the ascending valve flag is set to "1" to prepare for ascending, and the descending flag position is “0” means that the work equipment 3 is above the lowering limit position indicated by the lowering limit value.
Set the ascending valve flag to "0" to prepare for descending.

The valve-on time calculation in step 826 is performed according to the flowchart shown in FIG. 4, and the rising valve flag is “
Depending on whether the flag is "1" or "0", it is determined whether the falling on time or the rising on time is calculated (step 5261).

If the rising valve flag is “0”, the falling on time calculation is performed (step 8262), and the rising valve flag is “0”.
1″, the rise on time is calculated (step 5
26.3). The on-time calculation is performed based on the calculation table shown in FIG.

Processing from the second cycle onward when the operation switch 18 is in the A position, and when the operation switch 18 is in the A position to N
In the case of returning to the position, the processing up to step S12 is performed in the same manner as described above. In the process of the second cycle, if the work machine 3 is still descending, step S13
The determination becomes affirmative, and the process proceeds to step S27, where it is determined whether the rising flag or the descending flag is set.

Since the descending flag is set in step S20,
It is determined that step S27 is affirmative, and the process proceeds to step 828, where a stop flag is set.

Since the descending flag was set in step S20 of the previous process, the determination of the descending flag in step 318 is "1", and step S19 is skipped.

Thereafter, the processing up to step 826 is executed in the same manner as described for the flow of the first cycle.

In this way, once the operating switch 18 is moved to the A position and then returned to the N position, the lowering operation of the work implement 3 continues until the lift change amount becomes "0".

If the operation switch 18 is in position D, step S16
The steps up to this point are executed as explained above. The determination in step S17 is affirmative, and the process proceeds to step S29, where the ascending flag is set and the descending flag is cleared.

In step S30, the lift change amount setting unit 35 stores the lift deviation calculated in step S2.

In step S31, a raised position flag for determining the position of the working machine 3 is determined. If the ascending position flag is "1", the ascending valve flag is set to "1" (step 53).
2) If the flag is “0”, set the descending valve flag to “0”.
” (step S33).

Since the descending flag is cleared in step S29,
The determination result in step S18 is "0" and step S18 is determined.
Proceed to step 19.

Since the operation switch 18 is in position D, step S1
9 is negative, steps 820 to S24 are skipped, and the process proceeds to steps S25 and 826.

In step 326, the valve-on time is calculated based on the lift change amount set in step S30. The lift valve 27 operates according to the on-time, and the work implement 3 rises. The process when the operation switch 18 is returned from the D position to the N position is the same as the process when the operation switch 18 is returned from the A position to the N position, so a description thereof will be omitted.

If the operation switch 18 is in position B, step S
The determination of ll is affirmative, and the process advances to step S34, where the rise flag is cleared.

Since the operation switch 18 is operated to another position via the N position, the stop flag is cleared in the process at the N position (step 514), and therefore the determination result in step S35 is "0". , proceed to step 836.

At step 836, the fine adjustment down flag is set to "1". The fine adjustment lowering flag allows it to be determined whether the operation switch 18 is operated to position B or not.

In step S37, the downward deviation is stored in the lift change amount setting section 35.

In step 838, in order to determine the position of the work equipment 3,
The lowering position flag is determined. The lowering position flag is “
If, in step S39, the ascending valve flag is set to "1" and the descending position flag is 0", then
In step S40, the rising valve flag is set to "0".

The rise flag is set to "0" when the operation switch 18 passes through the N position, and the rise flag is set to "0" when the operation switch 18 passes through the N position.
4 is also cleared, so the determination in step 816 becomes "O" and the process advances to step S17. Operation switch 1
8 has been operated to position B, the determination in step S17 is negative and the process proceeds to step 818.

Like the up flag, the down flag is also set to "0" when the operation switch 18 is operated to the N position, so the determination result in step S18 is "0", and the process proceeds to step S19.

Since the operation switch 18 is in position B, the determination in step S19 is negative, and the lowering protection process in step S25 and the valve-on time calculation in step 826 are performed.

If the operation switch 18 is in position C, step S
The determination of IO is affirmative, and the descending flag is cleared in step S41.

Since the stop flag was cleared in step S14, it is determined to be "0" in step S42, and the stop flag is determined to be "0" in step S42.
Proceed to step 3.

In step S43, the lift deviation is stored in the lift change amount setting section 35.

In step S44, in order to determine the position of the work equipment 3,
The ascending position flag is determined. The ascent position flag is “
1”, the rising valve flag is set to “1” in step S45, and if the lowering position flag is “0”, the rising valve flag is set to “0” in step S46.
” is set.

Thereafter, as in the case where the operation button 18 is B, the processing up to step 326 is performed.

Note that while the operation switch 18 is being operated to the A position and descending,
Or, if the operating switch 18 is switched from position A to position C or from position D to position B while the operating switch 18 is moved to position D and is being raised, the work equipment 3 will be forced to move up or down. It can be stopped automatically.

For example, if the operation switch 18 is in position A and is descending, if you switch the operation switch 18 to position C,
The determination in step S10 is affirmative, and the process proceeds to step S41, where the descending flag is cleared. Before switching the operation switch 18 from position A to position C, the stop flag is set in step 52g, so the determination result in step S42 is "
1'', the process moves to step S15, and the lift change amount setting section 35 is set to the lift change amount "0".

After step S15, processes from steps S16 to S26 are executed, and in step 82B, the valve-on time is calculated, but since the lift change amount is "0" in step S15, the valve-on time is "O". , work equipment 3
The descent of is stopped.

Next, the fall protection process in step S25 will be explained with reference to the flowchart in FIG.

If the lift limit value setting knob is operated while the engine is stopped and the lift limit value has moved to a position lower than the current lift value of the work equipment 3, start the engine and turn the operation switch 18 to C. Or, if you try to raise the work equipment 3 by moving it to position D, the work equipment 3 will descend, following the lift limit value set at a lower position than the current lift value, contrary to the operator's will. .

The lowering protection process is a control for preventing such a lowering operation of the work implement 3 on the wrong side.

First, in step 5251, it is determined whether the engine is stopped. If the engine is stopped, the process advances to step 5252, where the lowering protection flag is set to "1".

When the engine is started, the determination in step 5251 becomes negative and the process moves to step 5253.

In step 5253, the falling protection flag is determined. Since the lowering protection flag is set to '1' while the engine is stopped, the process advances to step 5254.

In step 5254, the elevated position flag is determined. If the current lift value is greater than the ascent limit value, that is, if the current lift position is above the ascent limit position, the ascent position flag is "0" and step 5254
The process then proceeds to step 5255.

In step 5255, a determination of the falling flag is performed.

The lowering flag is set to "1" when the operation switch 18 is operated to the A position to lower the working machine 3. If the descending flag is set to "1", the process returns to the main routine (step 526), and if the descending flag is set to "0", the process proceeds to step 5256.

In step 5256, the fine adjustment down flag is determined. The fine adjustment lowering flag becomes "1" when the operation switch 18 is operated to position B to lower the working machine 3.
is set. If the fine adjustment down flag is set to "1", the process returns to the main routine (step 526).
If the fine adjustment down flag is set to "0", the process advances to step 5257.

In step 5257, the lift change amount setting means 28 is set to “
0'' is set.

When "0" is set in the lift change amount setting section 35 in step 5257, the lift change amount set in step 5257 is given priority over the lift change amount set in the lift change amount setting section 35 before the descent protection process. The amount of change “0” is valid.

Therefore, after the downward protection process, the step 82
At B, the valve-on time is calculated according to the amount of change in lift, so the work implement 3 is not raised or lowered. In other words, a locked state of the vertical movement is established.

When the descending flag and the fine adjustment descending flag are set to "1", that is, the operation switch 18 is pressed to A or B.
If you try to lower the work equipment 3 by operating it to the position, step 5257 is skipped as described above, so the lift change amount set before the descent protection process is valid. Then, the working machine 3 is lowered.

Work equipment 3 until the current lift value falls below the lift limit value.
When the flag is lowered, the raised position flag becomes "1", and the process moves from step 5254 to step 8258.

In step 8258, the falling protection flag is set to "0". When the falling protection flag is set to "0", the determination result in step 5253 becomes "0", and step 8
254 to 5257 and chip 5258 are skipped.

- Once the descent protection flag is set to "O", the descent protection flag will not change to "1" until the engine is stopped. Therefore, depending on the descent protection process, the lift change amount will not become "0".

That is, after operating the operation switch 18 to the lowering side, when the work equipment 3 descends until the current lift value becomes lower than the upper limit value, the locked state is released and the unlocked state is maintained until the engine stops. be done.

As described above, according to the present embodiment, the positional relationship between the current lift value and the lift limit value of the work equipment 3 is determined using the lift position flag, and according to the determination result, the lifting/lowering operation is performed only when necessary. A lock condition has been formed that disables the

In other words, if the lift limit value is lower than the current lift value, the work equipment 3 will descend against the operator's will even if the operation switch 18 is operated to the upward side. If so, a locked condition is formed.

On the other hand, even in the above positional relationship, when the operation switch 18 is operated to the lowering side, the locked state is not formed;
The work machine 3 is lowered according to the worker's will.

After the working machine 3 is lowered below the ascent limit position, the locked state is automatically released.

(Effects of the Invention) As is clear from the above description, according to the present invention, the following effects can be achieved.

(1) If you accidentally touch the setting knob while the engine is stopped and set the ascent limit position lower than the current height of the work equipment, It can be detected by comparing the set value of the ascent limit position and the current height position of the work equipment at the time of startup.

Based on this detection result, it is possible to create a lock state that disables the work equipment from moving up or down, so the work equipment will no longer be forced to descend even if the operating switch is tilted to the upward direction. .

(2) Since a state of erroneous operation can be detected by comparing the set value of the ascent limit position and the current height position of the working machine, a locked state can be created only when necessary. Therefore, there is no need to perform a troublesome operation to release the lock each time the engine is started, and the operation can be simplified.

(3) The locked state can be released by simply tilting the operation switch toward the lowering side, so the operation is easy.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a control device showing one embodiment of the present invention, FIGS. 2, 3 and 4 are flow charts showing the operation of the present invention, FIG. 5 is a contact configuration diagram of an operation switch, and FIG. Figure 6(a) is a front view of the conductive slide member, Figure 6(b)
) is a side view of Fig. 6(a), Fig. 7 is a diagram of the relationship between on time and lift change amount, Fig. 8 is a side view of the traveling work vehicle, and Fig. 9 is a side view of Fig. 6(a).
The figure is a perspective view showing a connecting portion of a traveling work vehicle and a work machine. 1... Traveling vehicle, 3... Ground work equipment, 7, 13...
・Hydraulic actuator, 15... Lift sensor, 18
...Operation switch, 20...Rise limit setting device, 21
... Ascent deviation calculation unit, 22... Falling limit value setting device,
23...Descent deviation calculation unit, 24...On time duty ratio storage unit, 25...Valve selection drive unit, 26...
- Downward valve, 27... Upward valve, 34... Engine rotation detection section, 35... Lift change amount setting section, 36
...A position judgment section, 37...B position judgment section, 38.
...Descent Protection Department, 39...Lift change amount "0" Memory Department Agent Patent Attorney Michito Hiraki and 1 other person Figure 2 (Part 3) SE, ＼ 宕 郎 Figure 6 (b) m ■

Claims (2)

[Claims] (1) An ascent limit value setter that sets the ascent limit position of the work equipment, a descent limit value setter that sets the descent limit position, and the deviation between the current height of the work equipment and the said ascent limit position detected by the sensor. an ascent deviation calculation section that calculates the deviation between the current height and the descent limit position, and a descent deviation calculation section that calculates the deviation between the current height and the descent limit position; and a valve selection that selects one of the descending deviations calculated by the descending deviation calculating section and operates either the rising valve or the descending valve of the hydraulic actuator for lifting and lowering the work equipment in the direction to eliminate the deviation. A lift control device for a ground-based working machine having a drive unit, when the engine is started, means for detecting the positional relationship of the current height of the working machine with respect to the lift limit position; Means for forming a locked state in which the work equipment is not driven to rise or fall even if the lifting operation switch is operated to the upward side when it is detected that the current height is at the upper level, and when the operating switch is operated to the downward side. means for detecting that the work equipment is lowered by temporarily releasing the locked state in response to the detection result of the detecting means; After the working machine has been lowered until the current height of the machine is below the ascent limit position, the above-mentioned lock state is continued to be released until the engine is stopped. Lifting control device for work equipment. (2) The means for forming the locked state is a means for setting the lift change amount, which is basic data for setting the on-time duty ratio of the ascending valve and descending valve to "0", to "0". The elevation control device for a ground-based working machine according to claim 1.