JPH0640239Y2 - Automatic lift control system for cargo handling vehicles - Google Patents

Description

TECHNICAL FIELD The present invention relates to an automatic lifting control device for a cargo handling vehicle such as a forklift.

Conventional technology and its problems Conventionally, lift detectors such as rotary encoders that continuously detect the lift of attachments of forklifts, and attachments are automatically detected until the lift detected by the lift detector reaches the required target lift. 2. Description of the Related Art There is known an automatic lifting control device having a lifting control means for lifting or lowering the moving body to stop it.

When the attachment is automatically raised or lowered by such an automatic lifting control device, it is necessary to immediately stop the attachment when a dangerous situation occurs.

It is an object of the present invention to provide an automatic lift control device for a cargo handling vehicle that can immediately stop the attachment when a dangerous situation occurs when the attachment is automatically raised or lowered. .

The automatic lifting control device for a cargo handling vehicle according to the present invention is a manual lifting control lever for manually raising and lowering an attachment supported by an outer mast of the cargo handling vehicle, and a manual lifting control operation. A lever operation detector for detecting that the lever has been operated to the up or down side, a target lift input means for inputting information about the target lift, and a manual lift control operation lever, which are separately provided. Information about the target lift was input by the automatic lift control start signal input means for inputting the automatic lift control start signal, the lift detector for continuously detecting the lift of the attachment, and the target lift input means. After that, when the dynamic lift control start signal is input by the automatic lift control start signal input means, the attachment is automatically attached until the lift detected by the lift detector reaches a predetermined target lift. In the case where automatic lifting control means for manually raising or lowering and stopping, and automatic lifting control by the automatic lifting control means are being performed, the lever for operating the manual lifting control is operated by the lever operation detector. It is characterized in that it is provided with a means for stopping the automatic lifting control by the automatic lifting control means when it is detected that it has been operated.

Embodiment FIG. 1 shows the overall construction of an automatic lift control device for a forklift. The automatic lifting control device is mounted on the hydraulic circuit (2) of the lift cylinder (1) and the outer mast, and lifts the attachments such as forks and container hangings (when the inner mast is at the lowest position. A rotary encoder (3) for detecting the height displacement of the inner mast with respect to the outer mast, an origin detection switch (4) attached at a predetermined height position of the outer mast, and a predetermined height position of the outer mast, respectively. The first to third lift confirmation switches (5), (6), (7), and the mast for detecting the forward tilted state of the mast (the tilted state in which the upper end of the mast is located forward of the lower end). Forward tilt detection switch (8), lever operation detection switch (10) (11) for detecting that the lift operation lever (9) has been operated from the neutral position to the upside or downside, engine speed Pedal depression detection switch (13) for detecting that the accelerator pedal (12) has been depressed until the number of revolutions reaches the maximum torque, the control panel (14), and a control device (15) for controlling each of the above devices. ) Is provided.

Switches (4) to (8), (10) (11) and (13)
As such, a limit switch, a proximity switch, or the like is used. The origin switch (4) turns on when the lift is, for example, 535 mm, and the first lift confirmation switch (5) detects the lift, for example.
It turns on at 1905 mm, the second lift confirmation switch (6) turns on at a lift of 4215 mm, and the third lift confirmation switch (7) turns on at a lift of 5475 mm. The mast forward tilt detection switch (8) is attached, for example, so that the mast is turned on when the mast is in the neutral (vertical) state and the backward tilted state, and is turned off when the mast is tilted forward or vice versa. For example, one of the lever operation switches (10) and (11) is turned on when the lever (9) is tilted upward, and the other is turned on when the lever (9) is tilted downward. Attached to. The pedal depression switch (13) is attached so as to be turned on based on the operation of the accelerator pedal, for example, when the engine speed is equal to or higher than the maximum torque.

The lift cylinder (1) is connected to the main pump (22) and the tank (23) via a lift valve (21). The main pump (22) is driven by an engine (not shown) whose rotation speed is controlled by the accelerator pedal (12). The lift valve (21) includes a raising pilot port (U) and a lowering pilot port (D). When pressure oil is supplied to the raising pilot port (U), the pump (22) moves to a cylinder ( 1), and when pressure oil is supplied to the descending pilot port (D), the cylinder (1) is switched to a position where it is connected to the tank (23). And the opening degree at each switching position is
It is controlled by the hydraulic pressure supplied to each port (U) (D).

The lift pilot port (U) of the lift valve (21) is connected to the solenoid valve for automatic raising (25U) and the solenoid valve for manually raising (26U) via the shuttle valve (24) for lowering. The pilot port (D) is connected to an automatic lowering solenoid switching valve (25D) and a manual lowering solenoid switching valve (26D) via a shuttle valve (27). The solenoid valves (26U) (26D) for manual ascent and descent are normally in the open position, and these solenoids have a-contact (2
It is connected to the control device (15) via 8). The solenoid valves (25U) (25D) for automatic raising and lowering are normally in the closed position, and these solenoids have a-contact (29).
Is connected to the control device (15) via.

Solenoid selector valve for manual raising or lowering (26U) (26D)
In accordance with the operation of the lift operation lever (9), pressure oil is sent from the lift valve control pump (30). The automatic raising electromagnetic switching valve (25U) is connected to the lift valve controlling pump (30) via the raising electromagnetic pressure reducing valve (31U) controlled by the control device (15). The automatic lowering electromagnetic switching valve (25D) is connected to the lift valve control pump (30) via the lowering electromagnetic pressure reducing valve (31D) controlled by the control device (15).

FIG. 2 shows the operation panel (14). On the upper surface of the operation panel (14), there are a display (40) and a display (40) for displaying the desired lift (specified lift) of the attachment or the current lift (actual lift) of the attachment. An indicator light (41) indicating that the actual lift height is displayed, an indicator light (42) indicating that the designated lift height is displayed on the display (40), and a numeric keypad for inputting the designated lift height ( 43), 7 lift selection keys (44) for specifying the storage location in the RAM (62) (see FIG. 3) when storing the specified lift in advance, and for specifying the stacking level of the container (50), a memory key (51) used for storing a specified lift, a memory recall key (52) used for recalling the stored specified lift, and for performing a lift control by designating the number of container stages Enter the designated container key (53) and designated lift into the numeric keypad (43). Lifting control key (54), start key (55) and cancel key (56) used when lifting control is performed by calling from the force or RAM (62).
Is provided. An emergency stop key (57) and its reset key (58) are provided on the side surface of the operation panel (14) for forcibly turning off the a contacts (28) (29) and holding the state. . Further, the operation panel (14) is provided with a buzzer (59) (see FIG. 3). Illuminated switches are used as the lift selection keys (44) to (50), the memory key (51), the memory recall key (52), the container designation key (53), and the lift designation key (54). .

FIG. 3 shows an electrical configuration of the automatic lifting control device. Automatic lift control system, central processing unit (CPU) (60)
Controlled by. The CPU includes a ROM (61) for storing the program and a RAM (62) for storing various data. The CPU (60) includes a lift detection unit (63), a lift confirmation unit (64), a lever operation detection unit (65), an accelerator pedal depression detection unit (66), a mast forward tilt detection unit (67), and an operation. The section (68) and the lift valve control section (69) are connected via the bus (70).

The lift detection section (63) includes a rotary encoder (3), a counter (71) that counts output pulses of the encoder (3) and outputs an actual lift signal, an origin switch (4), and an origin switch (4). A reset signal generation circuit (72) that outputs a counter reset signal based on a detection signal, and a lift origin detection circuit (73) that outputs a lift origin detection signal based on the detection signal of the origin switch (4). There is.
The lift confirmation section (64) includes first to third lift confirmation switches (5) to (7) and detection circuits (74) to (76) connected to the switches (5) to (7). It is configured. The lever operation detection section (65) has a lever operation detection switch (1
0) (11) and a detection circuit (77) connected to both switches (10) (11). The accelerator pedal depression detection unit (66) includes a pedal depression detection switch (13) and a detection circuit (7) connected to the switch (13).
It is composed of 8). The mast forward tilt detector (67)
The mast forward tilt detection switch (8) and a detection circuit (79) connected to the switch (8).

The operation section (68) includes a keyboard (80) having keys on the operation panel (14) and an interface circuit (81) thereof, a display (40), a buzzer (59) and a drive circuit (82) thereof. ing. The lift valve control section (69) includes a pressure reducing valve opening command signal creating circuit (83) and a pressure reducing valve switching circuit (8
4) and the outputs of these circuits (83) (84)
Constant / current amplifier (85) that outputs control signals for the pressure reducing valve (31U) or pressure reducing valve (31D), and automatic / manual switching that controls on / off of the a contacts (28) and (29) It consists of a circuit (86). Constant current amplifier (8
5) Inside the rising pressure reducing valve (31U) and lowering pressure reducing valve (31U)
There is an ascending side a-contact (85U) and a descending-side a-contact (85D) for switching between D) and ON / OFF of both contacts (85U) (85D) by the pressure reducing valve switching circuit (84). Is controlled.

FIG. 4 shows the contents of the RAM (62). In RAM (62), E is used as a lifting table for container stages.
1, Elias for storing desired lift E2, soft start operation command pattern memory area E3, soft stop operation command pattern memory area E4, operation command pattern creating area E5, used as an automatic lift stop flag Elijah
E6, first to third lift confirmation switches (5) (6) (7)
Areas E7 to E9 for respectively storing the lifts h1, h2, and h3 corresponding to the above, and an area E10 for storing a lift confirmation allowable value δ are provided. E1 used as a container stage-compatible lift table, operation command pattern memory area E3 for soft start, operation command pattern memory area E4 for soft stop, first to third lift confirmation switches (5)
(6) Areas E7 to E9 storing the lifts h1, h2 and h3 respectively corresponding to (7) and an area E10 storing the lift confirmation allowance δ may be provided in the ROM (61). .

Use the keys (44) to (5
There are first to seventh storage locations e11 to e17 corresponding to 0).
The storage locations e11 to e14 store the lifts of the attachments suitable for loading the containers with the height of 8 feet and 6 inches on the fifth to second stages, respectively, and the storage locations e15 to e17 are stored in the storage locations e15 to e17. Has the attachment lifting heights suitable for loading the containers of 9 feet and 6 inches in height from the fourth stage to the second stage.

The area E2 has first to seventh memory locations e21 to e27 corresponding to the keys (44) to (50).

In the area E3, an operation command pattern for gradually increasing the speed at the time of starting / lowering the attachment, that is, at the time of starting / lowering the attachment, the pressure reducing valve (as the difference ΔH (set value) between the designated lift and the actual lift is reduced ( 31U) (3
A pattern that increases the opening of 1D) is stored in advance.

In the area E4, the pressure reducing valve (as the operation command pattern, that is, the difference ΔH (absolute value) between the designated lift and the actual lift when the attachment lift is stopped is gradually reduced in order to gradually reduce the speed when the attachment lift is stopped. 31U) (31D)
A pattern in which the opening degree V of V is reduced is stored in advance. The area E5 is used to create an operation command pattern based on the difference between the designated lift and the actual lift and the patterns stored in the areas E3 and E4 in the attachment raising process and the attachment lowering process described later. .

Elias E6 has a location used as a cancel key operation flag F1 indicating that the cancel key (56) has been turned on.
e61, a place e62 used as a lever operation flag F2 indicating that the lever (9) has been operated, a place e63 used as a mast forward tilt flag F3 indicating that the mast is in a forward tilted state, and an accelerator pedal (12) Location e64 used as a pedal non-operation flag F4 indicating that the pedal is not depressed, location e65 used as an emergency stop key operation flag F5 indicating that the emergency stop key (57) is turned on, and the first lift Location used as the first lift abnormality flag F6 that indicates that the lift error exceeds the allowable value in the lift confirmation based on the confirmation switch (5)
e66, a place e67 used as a second lift abnormality flag F7 indicating that the lift error exceeds the allowable value in the lift confirmation based on the second lift confirmation switch (6), and the third lift In the lift confirmation based on the confirmation switch (7), there is a place e68 used as the third lift abnormality flag F8 indicating that the lift error exceeds the allowable value.

The lifts h1 to h3 are stored in advance in the areas E7 to E9. In addition, the allowable value δ used in the elevation confirmation is stored in advance in the area E10.

In this automatic lifting device, the first lifting control process for automatically moving the container to a predetermined stack height, the second lifting control for automatically moving the attachment to the lifting height input by the ten-key (43). Lifting control processing, RAM in advance
A third lift control process of storing one of the lifts stored in the storage locations e21 to e27 of (62) and automatically moving the attachment to the stored lift, a predetermined lift To
A lift storage process for storing in a predetermined storage location e21 to e27 of the RAM (62) is performed.

With reference to FIG. 2, the operation of the driver for executing each of the above processes will be described.

At any time, the indicator light (41) and the container designation key (53) are lit, and the actual lift is displayed on the display (40), which is in the input waiting state. When designating the first lift control process, first, the content designating key (53) is pressed, the desired stacking stage is designated by the lift selection keys (44) to (50), and the accelerator pedal (12) is selected. After depressing (however, pedal depression is not necessary when descending), then press the start key (55). By this operation, the indicator light (41) is turned off and the indicator light (42) is lit, and the display (40) displays the lifting height corresponding to the designated stacking stage. Lifting selection keys (44) ~ (50)
Of these, keys (44) to (47) are for containers with a height of 8 feet 6 inches, key (44) is in the 5th row, key (45) is in the 4th row, and key (46). Is the third row, key (47)
Is for designating the second stage respectively. Also,
Keys (48) to (50) are for containers with a height of 9 feet and 6 inches. Key (48) is the 4th stage, key (49) is the 3rd stage, and key (50) is the 2nd stage. Each of the keys (44) to (47) is provided with a letter indicating that the eye is to be designated. For example, 8 feet 3 high
When moving an inch container to the height of the 4th level, press the content specification key (53) and then the lift selection key (4
Press 5) and press the start key (55). As a result, the first lifting control process is executed and the container is moved to the height of the fourth stage. Then, when this process ends, the buzzer (59) is driven and the state returns to the input waiting state.

To specify the second lift control process, first press the lift specification key (54), enter the desired lift using the numeric keypad (43), and then depress the accelerator pedal (12). , If you are descending, do not press down the pedal) and press the start key (55). By this operation, the indicator light (41)
Is turned off and the indicator light (42) is turned on, and the input lift is displayed on the display (40). Further, the second elevation control process is executed, and the attachment is moved to the input elevation. Then, when this process ends, the buzzer (59) is driven and the state returns to the input waiting state.

When designating the third lift control processing, first, the lift specification key (54) is pressed, the memory recall key (52) is pressed, and the memory location () is selected by the lift selection keys (44) to (50). e21 to e27)
Specify, and depress the accelerator pedal (12) (however, in the case of descending, pedal depression is not necessary), and then press the start key (55). By this operation, the indicator light (41) is turned off and the indicator light (42) is turned on, and the lift height recalled from the designated storage location is displayed on the display (40). Also,
The third lift control process is executed, and the attachment is moved to the lift stored in the designated storage location. Then, when this process ends, the buzzer (59) is driven to return to the input waiting state. After the first to third lift control processes are started, the indicator light (42) is turned off, the indicator light (41) is turned on, and the actual lift is displayed on the display (40). .

Lifting height setting key (54) when setting the lifting memory processing
Press, enter the desired lift with the numeric keypad (43),
Press the memory key (51), set the memory location (e21 to e27) using the lift selection keys (44) to (50), and press the start key (5
5) Press. By this operation, the indicator light (41) is turned off and the indicator light (42) is turned on, and the input lift is displayed on the display (40). In addition, the lift height storage process is executed, and the input lift height is stored in the designated storage location. Then, when the processing is completed, the buzzer (59) is driven to enter the input waiting state.

If the cancel key (56) is pressed during each of the above operations, the operations up to that point are canceled. Also, while the attachment is moving,
When the emergency stop key (57) is pressed, the a contacts (28) (29)
Is switched from on to off and the attachment is stopped. At this time, the indicator lights (41) (42) and all the illuminated keys (44) to (54) blink. To release the emergency stop state, press the reset key (58).

FIG. 5 shows the overall processing procedure (automatic lift control processing) in the CPU. When the power is turned on, a lift origin passing request is displayed (step (101)). This display is performed by randomly displaying numerical values on the display (40) and blinking the indicator light (41). Seeing this display, the driver manually operates, that is, operates the operation lever (9) to move the attachment up and down. When it is detected that the predetermined reference position of the inner mast has passed the origin based on the detection signals of the lift origin detection switch (4) and its detection circuit (73) (step (10
2)), the counter (71) is reset, and a lift display program for displaying the actual lift is started at a cycle of 125 ms (step (103)). Further, the input waiting state is entered, the actual lift is displayed on the display (40), and the indicator light (41) and the container designation key (53) are turned on (step (104)). Then, the input of the key information and the vehicle state information is accepted (step (10
Five)). The vehicle state information includes a lift origin detection signal, a lift confirmation detection signal, a lever operation detection signal, an accelerator pedal depression detection signal, a mast forward tilt detection signal, and the like.

When the lever operation detection signal is input, the process returns to step (104) and remains in the input waiting state. When the emergency stop key (57) is pressed, the a contacts (28) (29) are held off, and the display (all illuminated switches (44) to (54) and instructions indicating the emergency stop is displayed. The lights (41) and (42) blink (step (106)). When the reset key (58) is pressed (step (107)),
The emergency stop state is released, and the process returns to step (105) to enter the input waiting state.

Also, during key input, the type and order of the input keys are checked. Then, the designated process is discriminated and executed (step (108)). When the first lift control processing is designated, the lift corresponding to the stage designated by the switches (44) to (50) is stored in the RAM (62) at the storage location e11 to
The lift height read from e17 is compared with the actual lift height, and the attachment raising or attachment lowering processing is executed according to the comparison result. When the second lift control process is designated, the lift input by the ten key (43) is compared with the actual lift, and the attachment raising or attachment lowering process is executed according to the comparison result. . When the third lifting control process is designated, the RAM (6) designated by the switches (44) to (50) is designated.
The lift height is read from the storage locations e21 to e27 in 2), and attachment raising or attachment lowering processing is executed according to the result of comparison between the lift height and the actual lift height. When the lift storage process is designated, the lift inputted by the ten key (43) is stored in the storage locations e21 to e27 of the RAM (62) designated by the switches (44) to (50). . Upon completion of each of these processes, the process returns to step (104) and waits for input.

FIG. 6 shows the overall procedure of the attachment lifting process in each of the first to third lifting control processes, and FIG. 7 shows the automatic lifting monitoring program that is periodically activated in the attachment lifting process. High monitoring processing procedure,
The figure shows the procedure of the attachment raising speed control processing by the attachment raising speed control program activated in the attachment raising processing.

Referring to FIG. 6, first, the automatic contact / manual switching circuit (86) turns on the a-contacts (28) (29) and the solenoid drive current changes the switching valve (25U) (25D) (26U).
By being sent to the solenoid (26D), the automatic raising and lowering switching valves (25U) (25D) are opened and the manual raising and lowering switching valves (26U) (26D) are closed. . That is, the switching valve (25U) (25D) (26U) (26
D) is automatically switched (step (111)).

Then, the attachment ascending speed control program is started up, and after the flags F1 to F8 are all cleared, the automatic elevation monitoring program is started up at a cycle of 50 ms (step (112)). After that, it waits until the attachment rising speed control processing by the attachment rising speed control program is completed (step (113)).

Referring to FIG. 7, in the automatic elevation monitoring process, first, the input of key information and vehicle state information is accepted (step (151)). Then, based on the input key information and vehicle state information, whether the cancel key (56) is turned on, whether the operation lever (9) is operated, whether the mast is in the forward leaning state, Whether the accelerator pedal (12) is not depressed,
It is sequentially checked whether or not the emergency stop key (57) is turned on. (Steps (152), (154), (156), (158),
(160)). If the cancel key (56) is turned on, the cancel key operation flag F1 is set (step (153)), and if the operation lever (9) is operated, the lever operation flag F2 is set (step (155). )),
If the mast is leaning forward, the mast leaning flag F3 is set (step (157)), and if the accelerator pedal (12) is not depressed, the accelerator pedal non-operating flag F4 is set (step (157)). 159)), the emergency stop key operation flag if the emergency stop key (57) is turned on.
F5 is set (step (161)).

Next, it is checked whether or not the first lift confirmation switch (5) is turned on (step (162)), and if it is turned on,
Proceed to step (163), and actual lift and its switch (5).
The difference ε with the lift (h1) corresponding to is calculated (step (163)). Then, it is checked whether or not the calculated difference ε is larger than the allowable value δ (step (164)), and if ε> δ, the corresponding lift error detection flag F6 is set (step (165)), The automatic elevation monitoring process ends. ε ≦
If δ, F6 is not set and the automatic elevation monitoring process ends.

When the first lift confirmation switch (5) is not turned on in the step (162), it is checked whether or not the second lift confirmation switch (6) is turned on (step (16)
6)). Then, if the second lift confirmation switch is ON, the difference ε between the actual lift and the lift (h2) corresponding to the switch (6) is calculated (step (163)), and the calculated ε is δ. It is determined whether or not it is larger than the above (step (164)),
If ε> δ, the lift error detection flag F7 is set (step (165)), and the automatic lift monitoring process ends.
If ε ≦ δ, F7 is not set and the automatic height monitoring process ends.

In the step (166), if the second lift confirmation switch (6) is not on, it is checked whether or not the third lift confirmation switch (7) is on (step (16
7)). If the third lift confirmation switch (7) is on, the actual lift and the lift (h3) corresponding to the switch (7)
Is calculated (step (163)), and it is determined whether the calculated ε is larger than δ (step (16)).
4)), if ε> δ, the lift error detection flag F8 is set (step (165)), and the automatic lift monitoring process ends. If ε ≦ δ, F8 is not set and the automatic height monitoring process ends.

Referring to FIG. 8, in the attachment ascending speed control process, first, the difference ΔH (absolute value) between the designated lift and the actual lift is obtained, and this ΔH and the areas E3 and E4 of the RAM (62) are determined. An operation command pattern for the valve opening V with respect to ΔH is created based on the soft start and soft stop operation command patterns stored in (step (131)). Next, the ascending side a contact (85U) provided in the constant current amplifier (85) is turned on (step (1
32)).

After this, it is checked whether or not any of the flags F1 to F8 is set (step (133)). If none of F1 to F8 is set, the difference ΔH between the designated lift and the actual lift is calculated (step (134)). And
A valve opening degree V (ΔH) corresponding to the calculated difference ΔH and the difference ΔH calculated based on the pattern created in the step (131) is obtained, and a signal corresponding to the valve opening degree V (ΔH) is obtained. Is sent to the valve opening command signal creation circuit (83) and the contact (85
A current having a value corresponding to the valve opening degree V (ΔH) is output to the pressure reducing valve (31U) via U) (step (135)).
After this, wait for 24 msec (step (136)). During this waiting, the attachment rising speed control program is in a waiting state. This waiting state is used for executing the elevation display program or the automatic elevation monitoring program.

When 24 msec has elapsed, it is judged whether or not the actual lift has reached the specified lift (step (137)), and if not, the process returns to step (133). If all the flags F1 to F8 are not set, steps (134) to (137) are executed again.
Is processed. In this way, step (13
3) to (137) are repeatedly executed, and when the actual lift reaches the specified lift (YES in step (137)), the a contact (85U) is turned off (step (138)), and then the attachment rises. The speed control process ends. As a result, the attachment is stopped at the designated lift.

In the step (133), among the flags F1 to F8,
If even one is set, the constant current amplifier (85) reduces the valve opening V by a predetermined value ΔV.
8ms after the output current of is controlled (step (139))
Wait (step (140)). After this, it is checked whether or not the valve opening V is less than or equal to zero (step (141)). If V is not less than or equal to zero, the process returns to step (139) and the valve opening is set to a predetermined value. The output current of the constant current amplifier (85) is controlled again so as to be further reduced by ΔV. And after waiting 8ms (step (14
0)), it is again checked whether or not V ≦ O, and if it is not V ≦ O, the process returns to step (139). In this way, steps (139) to (141) are repeatedly executed, and step (14)
When V ≦ O in 1), the process proceeds to step (138), where the contact (85U) is turned off.

Therefore, when any one of the flags F1 to F8 is set in step (133), that is, when the cancel key (56) is pressed while the attachment is rising, the operation lever (9) is operated. When the mast is tilted forward, when the accelerator pedal (12) is returned, when the emergency stop key (57) is pressed, or when the lift confirmation switches (5) to (7) are pressed. At the time of turning on, when the difference between the actual lifting height and the lifting height corresponding to the turned-on switches (5) to (7) exceeds the allowable value δ, step (13
9) ~ (141) causes the attachment to be soft stopped. After the contact (85U) is turned off, the attachment rising speed control process ends.

In the first to third lift control processes, the accelerator pedal (12) is not depressed or the accelerator pedal (12) is not depressed enough (the engine speed is lower than the maximum torque speed). If the start key (55) is pressed as is, the accelerator pedal operation flag F4 is set in the first automatic elevation monitoring process after the attachment ascending speed control process is started. Therefore, in such a case, in the attachment ascending speed control process, steps (133) to (137) are executed for a minimum time of less than 1 second, and then step (133).
Since the answer is YES, the attachment will not be raised. That is, in this case, the pressure oil is not actually sent to the lift valve (21), and the start of the lift control process is substantially prohibited. With the mast tilted forward or the operating lever (9) being operated, press the start key (5
The same applies when you press 5).

When the attachment raising speed control process is completed, referring to FIG. 6, the periodic activation of the automatic elevation monitoring program is stopped (step (114)). Then, it is judged whether or not the emergency stop key operation flag F5 is set (step (115)), and if it is set, the a contact (28)
(29) is turned off and the switching valve (25U) (25D) (26U) (2
6D) is switched to the manual side (step (117)).
If flag F5 is not set (step (11
5) NO), it is determined whether the operation lever (9) is in the neutral position (step (116)), and if it is in the neutral position,
If the switching valve (25U) (25D) (26U) (26D) is switched to the manual side (step (117)) and it is not in the neutral position, wait until it reaches the neutral position, then switch valve (25U) (25D) )
(26U) and (26D) are switched to the manual side (step (117)).

Next, of the flags F1 to F8, it is determined whether only the accelerator pedal non-operation flag F4 is set (step (118)). If only the flag F4 is set, the key information and the vehicle Input of state information is accepted (step (119)). Then, based on the entered key information and state information, the cancel key (5
The on / off state of 6), the on / off state of the emergency stop key (57), and whether or not the operation lever (9) is operated are sequentially examined (steps (120) to (122)). If the cancel key (56) is on (YES in step (120)), the emergency stop key (57) is on (YE in step (121).
S) and when the operation lever (9) is operated (YES in step (122)), the attachment raising process ends.

If the cancel key (56) and the emergency stop key (57) are off and the operating lever (9) is not operated (NO in steps (120) to (122)), the accelerator pedal (12)
Is checked (step (12
3)), if the accelerator pedal (12) is depressed,
Returning to step (111), the attachment raising process is executed again. In step (123), if the accelerator pedal (12) is not depressed, the buzzer (59) is driven to make an accelerator pedal depression request (step (124)), and then the above step (114). In step (125), it is checked whether or not 5 seconds have elapsed since the start of the automatic elevation monitoring program was stopped. If 5 seconds has not elapsed, step (11
Returning to step 9), the processes of steps (120) to (124) are executed. Then, steps (121) to (122) result in NO, and if YES in step (123), the process returns to step (111).
The attachment raising process is executed again. Even if NO in steps (121) to (122), N in step (123)
If it is O, the processes of step (119) to step (125) are repeated, and if it is determined in step (125) that 5 seconds have elapsed, the attachment raising process ends.
Further, when the processes of steps (119) to (125) are repeatedly performed and the answer of step (120), (121) or (123) becomes YES, the attachment raising process also ends. In other words, if the accelerator pedal (12) is once returned while the attachment is rising, the attachment raising speed control is performed by steps (133), (139), (140) (141) and (138). Although the processing is completed, within 5 seconds, the driver does not press the cancel key (56) and the emergency stop key (57) and does not operate the operation lever (9), and again the accelerator pedal ( 1
If you step 2), the attachment raising process is executed again and the attachment is raised.

FIG. 9 is a time chart showing the execution state (R) of each program, the waiting state (W), and the pause state (S) due to periodic activation in the attachment raising process. As for the priority of each program, the attachment elevation control program has the highest priority, the automatic elevation monitoring program has the second highest, the fork elevation program has the second highest, and the elevation display program has the lowest priority.

First, the steps (11
After 1) to (112) are executed, the attachment raising program goes into a waiting state. And step (112)
Causes the attachment ascending speed control program to be activated, and the automatic elevation monitoring program to be cyclically activated, whereby the attachment ascending speed control program is executed, and a 24 ms waiting state is entered in step (136). Then, when 24 ms elapses, the processes after step (137) of the attachment rising speed control program are executed. Therefore, the attachment rising speed control program repeats execution and waiting for 24 ms.

The automatic lift monitoring program is activated every 50 ms, but its priority is lower than that of the attachment ascending speed control program, so it is executed only when the attachment ascending speed control program is in the waiting state.

In addition, the lift display program is activated in a 125 ms cycle, but since it has the lowest priority, it is executed only when both the attachment ascent speed control program, the automatic elevation monitoring program, and the attachment ascent program are in the waiting state. .

When the attachment rising speed control program ends,
The process after the step (114) of the attachment raising program is executed, and the process of step (114) ends the automatic elevation monitoring program.

FIG. 10 shows an attachment lowering processing procedure by the CPU (60). First, switching valve (25U) (25D) (26U)
(26D) is switched to the automatic side (step (20D
1)), then, the attachment descending speed control program is started up, and after the flags F1 to F8 are all cleared, the automatic lift monitoring program is started up in a cycle of 50 ms (step (202)).

The attachment descending speed control processing and the attachment ascending speed control processing are almost the same, and in step (132) of the attachment ascending speed control processing, the descending side contact (85D) is turned on instead of the ascending side contact (85U). Point and rising contact (85U) at step (138)
The description will be omitted because the descending side contact (85D) is turned off instead of the above, and the point that the process proceeds to step (134) even if only the accelerator pedal non-operation flag F4 is set in step (138). . Further, the automatic elevation monitoring process is the same as the automatic elevation monitoring process in the attachment raising process, and therefore its description is omitted.

When the attachment descending speed control process is completed, the periodic activation of the automatic elevation monitoring program is stopped (step (204)). Then, it is judged whether or not the emergency stop detection flag F5 is set (step (205)), and if it is set, the a contacts (28) (29) are turned off and the switching valve (25U). (25D) (26U) (26D) is switched to the manual side (step (207)). If the flag F5 is not set (NO in step (205)), it is determined whether the operation lever (9) is in the neutral position (step (206)), and if it is in the neutral position, the switching valve (25U) (25
D) (26U) (26D) is switched to the manual side (step (207)), and if it is not in the neutral position, wait until it reaches the neutral position before switching valves (25U) (25D) (26U) (26D) ) Is switched to the manual side (step (207)).

In the above automatic lift control device, by designating the desired container stack using the lift selection keys (44) to (50), the lift corresponding to the stack is automatically set. For this reason, the operation in the high-loading work of containers becomes very easy.

Further, the rotary encoder (3) when the lift confirmation position is detected by the lift confirmation switches (5) to (7).
The lift detected by and the lift at each lift confirmation position are compared, and if the deviation between the two exceeds a predetermined allowable value δ, the automatic lift control is stopped, so the rotary encoder The attachment (3) does not rise or fall to the stroke end of the cylinder due to the failure. Therefore, it is possible to prevent the attachment from being raised or lowered beyond the limit, and to prevent the forklift from falling and the load from colliding with the ground.

Further, when it is detected by the lever operation detection switches (10) and (11) that the operation lever (9) is operated to the up side or the down side, the automatic lift control is stopped, so the automatic lift operation is stopped. When you want to stop the attachment for the purpose of avoiding the occurrence of dangerous situations,
By customary operation such as operating the operating lever (9),
The attachment can be stopped. For this reason,
The danger situation can be avoided promptly.

When the mast forward tilt detection switch (8) detects that the mast is in the forward tilt state, if the automatic lift control is being executed, the operation is stopped and the automatic lift control is being executed. Otherwise, the start of the automatic lift control is prohibited, so that the forklift can be prevented from tipping over due to the automatic lift control when the mast is leaning forward.

Furthermore, when the accelerator pedal (12) is not depressed until the engine speed reaches the maximum torque speed, the automatic lift control prohibits and cancels the automatic lift control. Sometimes it is possible to prevent the engine from stopping due to insufficient torque.

Effect of the Invention In the automatic lifting control device for a cargo handling vehicle according to the present invention, when the automatic lifting control is performed by the lifting control means, the lever operation detector moves the manual lifting control operation lever up or down. When it is detected that the vertical operation has been performed, the automatic lifting control by the lifting control means is stopped. Therefore, during automatic lift control, when it is desired to stop the attachment for the purpose of avoiding a dangerous situation, the attachment can be stopped by a customary operation such as operating the manual lift control operation lever. Therefore, it is possible to quickly avoid the occurrence of a dangerous situation.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an overall schematic configuration of an automatic lift control device for a forklift, FIG. 2 is a plan view showing the appearance of an operation panel, and FIG. 3 is an electrical configuration of the automatic lift control device. Block, Fig. 4 is a diagram showing the contents of RAM, Fig. 5 is a flowchart showing the overall processing procedure by the CPU, and Fig. 6 is a CP.
FIG. 7 is a flow chart showing an attachment raising process procedure by U, FIG. 7 is a flow chart showing an automatic elevation monitoring process procedure in an attachment raising process by CPU, and FIG.
FIG. 9 is a flowchart showing the attachment raising speed control processing in the attachment raising processing by the CPU,
FIG. 10 is a time chart showing the execution of each program in the attachment raising process, a waiting state and a sleep state by periodic activation, and FIG. 10 is a flowchart showing the attachment lowering process by the CPU. (3) ... Rotary encoder (lift height detector), (44) ~
(50)… Lifting height selection key (container stacking number specification key),
(60) ... CPU, (61) ... ROM, (62) ... RAM.

Claims (4)

[Scope of utility model registration request] Claim: What is claimed is: 1. A manual lift control lever for manually raising and lowering an attachment supported by an outer mast of a cargo handling vehicle, and the manual lift control lever is operated to a rising side or a descending side. Lever operation detector for detecting the fact that it has been operated, the target lift input means for inputting information on the target lift, and the manual lift control operation lever, which is provided separately and inputs the automatic lift control start signal. Automatic lift control start signal input means, lift height detector that continuously detects the lift of the attachment, automatic lift control start signal input after the target lift information is input by the target lift input means When the dynamic lift control start signal is input by the means, the attachment is automatically lifted or lowered to stop until the detected lift of the lift detector reaches a predetermined target lift. When the automatic lift control is being performed by the dynamic lift control means and the automatic lift control means, it is detected by the lever operation detector that the manual lift control operation lever has been operated to the up or down side. An automatic lift control device for a cargo handling vehicle, which is provided with means for stopping automatic lift control by the automatic lift control means at times. 2. A mast forward tilt detector for detecting that the outer mast is in a forward tilt state, and in the case where automatic elevation control is performed by the elevation control means, the outer mast is detected by the mast forward tilt detector. Mast forward leaning detection in a case where it is detected that the vehicle is leaning forward, when the automatic lifting control means stops the automatic lifting control and when the automatic lifting control means does not perform the automatic lifting control. The utility vehicle registration claim 1 provided with means for prohibiting the automatic lifting control by the automatic lifting control means when it is detected by the container that the outer mast is tilted forward. Automatic lifting control device in. 3. A detection for detecting that an attachment raising / lowering drive pump for generating an oil pressure for raising and lowering the attachment is driven by an engine and the engine speed is equal to or lower than the maximum torque. vessel,
When the automatic lift control by the automatic lift control means is being performed, when the detector detects that the engine speed has become less than or equal to the maximum torque speed, the automatic lift control means performs automatic lift control. When the means for stopping the high control and the automatic lifting control by the automatic lifting control means are not performed, when the detector detects that the engine speed is equal to or lower than the maximum torque speed, The automatic lift control device for a cargo handling vehicle according to claim 1, further comprising means for prohibiting the automatic lift control by the automatic lifting control means. 4. The automatic lifting control means, when loading a container or the like with a high load, a lift of an attachment suitable for loading work on each level of at least the second level or more from the bottom is previously set for each level. The stored storage means, the loading stage number designation key provided for the lifting height for each stage stored in the storage means, and the lifting stage for the number of stages designated by the loading stage designation key stored in the storage means The cargo handling work according to any one of claims 1 to 3, further comprising: means for raising or lowering the attachment to stop until the detected lift of the lift detector reaches a high height. Automatic lift control system for cars.