JP2003341993A - Control device for forklift - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent deterioration of work efficiency, cargo collapse, or damage to a pallet. <P>SOLUTION: As a fork is lowered by action of a lift cylinder, this control means 45 stops the action of the lift cylinder to temporarily stop lowering of the fork when it determines that the fork is lowered to a prescribed position (at 10 cm from the ground) based on output of a lift height detection sensor 51. Simultaneously, for releasing locking to the pallet by a pallet lock means, it controls a motor 31, and drives a power cylinder 30 to turn a rear end part of a lock bar upward, thereby locking to the pallet is released. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a forklift control device including pallet locking means for pressing a lower deck board of a pallet into which a fork is inserted to lock the pallet.

[0002]

2. Description of the Related Art Conventionally, an order picking track is constructed as shown in FIG. 11, for example. That is, FIG.
As shown in FIG. 1, the order picking truck 101 includes a vehicle main body 103, a mast device 105 standing upright in a substantially central portion of the vehicle main body 103, and a mast device on which a worker provided at a rear portion of the vehicle main body 103 is placed. A driver's cab 109 having a lift base 107 that moves up and down along 105, and a pair of forks 111 attached to the lower part of the lift base 107.
It is composed by.

A lock bar 113 is rotatably provided near the fork 111, and when the fork 111 is inserted into the pallet 115, the lock bar 113 presses the lower deck board of the pallet 115 at the same time. The upper deck board of the pallet 115 is pressed by the fork 111, so that the pallet 115 is locked.

Therefore, even when an operator moves from the cab 107 to the pallet 115 to perform work, the pallet 115 can be firmly fixed and the pallet 1 can be fixed.
It is possible to prevent the fifteen of the forks 111 from slipping off, and it is possible to safely work on the pallet 115.

By the way, when the fork 111 is inserted into the pallet 115, the tip of the lock bar 113 is rotated downward and locked.
As shown in FIG. 2, the pallet detection sensor 117 and the landing detection sensor 119, which are magnetic sensors, the power cylinder 121, the motor 123 that drives the rod of the power cylinder 121, and the both-end moving positions of the rod of the power cylinder 121 are detected. The lock bar 113 is rotated by the pallet locking means including the input / output detection sensors 125 and 127 composed of magnetic sensors and the control means 129 composed of a microcomputer for controlling these.

At this time, a magnet is embedded at the base side of the lock bar 113, and a landing detection sensor 119 is arranged above the pallet detection sensor 117. The pallet detection sensor 117 and the landing detection sensor 119 are provided on the lock bar 113. The magnetism is detected by the proximity of the magnet and reacts, and the horizontal state of the lock bar 113 is known by the reaction of the pallet detection sensor 117.

The lock bar 113 has a pallet 115.
In the state in which the lock bar 113 is locked, the magnet of the lock bar 113 is rotated to a position higher than the landing detection sensor 119. Therefore, the reaction of the landing detection sensor 119 causes the pallet 115 to land and the lock bar 1
It can be seen that the tip of 13 has returned to the state of being rotated downward by a predetermined angle.

Further, a magnet is also embedded in the rod of the power cylinder 121, and the input / output detection sensors 125, 12 are provided.
No. 7 detects the magnetism due to the proximity of the magnet of the rod and reacts, and it is understood that the reaction of the entrance detection sensor 125 indicates that the rod of the power cylinder 121 is in the housed state. It can be seen that the tip end of the lock bar 113 is extended and rotated downward.

Then, the fork 111 is moved to the pallet 115.
Pallet detection sensor 1 when it is inserted into the
When the 17 and the entrance detection sensor 125 react, the control means 1
The motor 123 is controlled by 29 to rotate the tip of the lock bar 113 downward, and the pallet 115 is automatically locked.

On the other hand, when the landing detection sensor 119 and the ejection detection sensor 127 react with the fork 111 inserted in the insertion port of the pallet 115, the control means 129 determines that the pallet 15 has landed, and the lock bar. The motor 123 is controlled to rotate the tip of the 113 upward, and the pallet 115 is automatically unlocked.

[0011]

However, the pallet 11
As described above, the unlocking of No. 5 is performed by the landing detection sensor 1
19 and the pallet 1 based on the reaction of the output detection sensor 127
Since it is a condition that 15 landings are detected,
After the picking work is completed, the fork 111 is moved to the pallet 11
In the case of pulling out from No. 5, the fork 111 can be pulled out from the pallet 115 only after the landing of the pallet 115 is detected and the lock is released, which causes a problem that work efficiency is lowered.

Further, while the lock release of the pallet 115 is not completed, the fork 111 is forced to the pallet 1 by force.
When trying to pull out from 15, the pallet 115 travels while being dragged, which may cause collapse of the load or, in the worst case, damage of the pallet 115.

It is therefore an object of the present invention to reduce work efficiency and prevent load collapse and pallet damage.

[0014]

In order to achieve the above-mentioned object, the present invention provides a forklift truck comprising pallet locking means for pressing the lower deck board of the pallet in which the fork is inserted to lock the pallet. In the control device, a lift detection sensor that detects the position of the fork that moves up and down, and the pallet lock when the lift detection sensor detects that the fork has moved down to a predetermined position. Release control means for controlling the release of the lock of the pallet by means (claim 1).

According to this structure, the release control is performed when the fork moves downward while the pallet is locked by the pallet locking means and the lift detection sensor detects that the fork has moved down to a predetermined position. The means unlocks the pallet by the pallet locking means.

Therefore, since the pallet is unlocked by the unlocking control means before the pallet is completely landed, it is not necessary to wait for the unlocking after the pallet is completely landed in order to pull out the fork from the pallet. Also, there is no reduction in work efficiency.

At this time, if the height detected by the lift detecting sensor is set at the lowest position, for example, about 10 cm from the ground, the pallet is unlocked when it is almost landed or slightly floated from the ground. Therefore, as in the past, even if the pallet has landed, the operator will not pull out the fork from the pallet while the lock is not completely released, and the load will collapse. It is possible to prevent the pallet from being dragged and damaged.

Further, according to the present invention, stop control means for stopping the downward movement of the fork when the downward movement of the fork to the predetermined position is detected by the lift detecting sensor, and the downward movement restarting operation. And a restart operation means for restarting the downward movement of the fork, which is stop-controlled by the stop control means, based on an operation (claim 2).

According to this structure, the stop control is performed when the fork moves downward while the pallet is locked by the pallet locking means and the lift detection sensor detects that the fork has moved down to a predetermined position. Since the lowering of the fork is stopped by the means, the operator can recognize that the fork has moved down to a predetermined position by stopping the fork.

Further, even when the lowering of the fork is stopped by the stop control means, the lowering of the fork is restarted by the operation of the restart operation means, and at the same time, the pallet locking is performed by the release control means based on the operation of the restart operation means. The pallet is unlocked by the means. Therefore, the pallet is clamped even at a predetermined low lift position, and as a result, it is possible to prevent the load from collapsing and the pallet from being dragged and damaged.

Further, according to the present invention, the execution start timing of the lock release control of the pallet by the release control means is set when the downward movement of the fork to the predetermined position is detected by the lift detection sensor, or A switching operation means is provided for performing switching setting at any time when the fork reaches the lowermost movement position based on the operation of the restart operation means (claim 3).

According to this structure, when the lift detection sensor detects the downward movement of the fork to the predetermined position,
Although the pallet lock control is performed by the release control means, the execution start timing of the lock release control is switched and selected by the switching operation means when the fork reaches the lowest position based on the operation of the restart operation means. The pallet unlocking control by the unlocking control means is not executed at the time when the fork is moved down to the predetermined position, but is started when the fork reaches the lowest position.

Therefore, depending on the work situation, the execution start timing of the lock release control of the pallet by the release control means is either when the fork moves down to a predetermined position or when the fork reaches the lowest position. It can be selected at the operator's discretion.

The present invention further comprises a pallet detection sensor for detecting that the fork has been inserted into the pallet, and the stop control means causes the pallet detection sensor to detect the pallet into which the fork is to be inserted. When it is not detected, the stop control of the fork is not performed (claim 4).

According to this structure, when the pallet is not detected by the pallet detection sensor, the stop control means does not need to perform stop control of the fork.
Fork stop control is not performed, and unnecessary control can be omitted.

According to the present invention, the forklift is
It is characterized by being an order picking truck in which a driver's cab is integrally raised and lowered together with the fork (claim 5). According to such a configuration, it is possible to provide an order picking truck that can automatically unlock the pallet.

[0027]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A first embodiment in which the present invention is applied to an order picking truck will be described with reference to FIGS. However, FIG. 1 and FIG. 2 are perspective views of the order picking truck as seen from diagonally rear and diagonally forward, respectively, and FIG.
4 and 5 are other right side views and operation explanatory views, respectively, FIG. 6 is a block diagram of a control system, and FIGS. 7 and 8 are operation explanatory views.

As shown in FIGS. 1 and 2, the order picking truck 1 according to the present embodiment is provided with a mast device 10 at the center thereof, and along this mast device 10, an operator's cab for boarding an operator. 3 is movably supported. A pair of forks 2 is fixed to the rear side of the vehicle body of the driver's cab 3, and a motor for driving the vehicle is provided on the opposite side of the fork 2, that is, in front of the vehicle body.
A drive unit 11 including a hydraulic motor that drives a device for cargo handling is arranged, and a fence-shaped head guard 12 is provided above the driver's cab 3 for operator protection. Further, a handlebar 13 is provided on the front left portion of the cab 3, and an operating device 18 including an accelerator for moving the vehicle body in the front-rear direction and a switch for raising and lowering the cab 3 and the fork 2 is provided on the right front portion. Has been. Further, a substantially U-shaped safety bar 14 for protecting the operator is provided above the driver's cab 3, and a brake pedal 16 is provided on the floor surface of the operator's cab 3 (the upper surface of the pedestal 4).

Next, the structure of the pallet locking means will be described with reference to FIGS. This pallet lock means 2
No. 0 has its drive part housed in a flat pedestal 4 below the cab 3, and a lock bar 21 for locking the pallet projects from the front plate 17 of the pedestal 4 in parallel with the fork 2. . The lock bar 21 is formed in a substantially L shape facing each other in a plan view, the base portion is bolted to a plate-shaped bracket 23, and the entire shape of the two lock bars 21 is formed in a substantially U shape. It is in a state.
In addition, an inclined portion 22 that is inclined downward toward the tip is formed at the upper part of the tip of each lock bar 21. The end portion of the bracket 23 is supported by a shaft 26 horizontally provided on the pedestal 4 so as to be vertically rotatable, whereby the lock bar 2
1 is vertically swingable around a shaft 26.

A power cylinder 30 as a driving means for the lock bar is arranged in the pedestal 4 in the longitudinal direction of the vehicle body. A rod 32 of the power cylinder 30 is attached to an end of the power cylinder 30. Motor 31
It can be expanded and contracted through a gear (not shown) by normal rotation and reverse rotation. Further, on both sides of the power cylinder 30, there are provided an input detection sensor 28 for detecting a state in which the rod 32 is housed and an output detection sensor 29 for detecting a state in which the rod 32 is extended. The entrance detection sensor 28 and the exit detection sensor 29 are composed of, for example, magnetic sensors.

A link body 34 is connected to the tip of the rod 32 via a shaft 36, and a lower end of the link body 34 is pivotally connected to a shaft 35 supported by the pedestal 4.
Further, one end of a damper 40 is rotatably connected to a center of the link body 34 by a shaft 37, and the other end of the damper 40 is connected to a protrusion 27 provided on the upper surface of the bracket 23 and the shaft 4.
It is rotatably connected via 1. This damper 40
As described below, absorbs the force applied to the lock bar 21 when the pallet 6 is locked, and a coil spring is arranged inside.

Now, as shown in FIG. 4, the power cylinder 3
When the rod 32 of 0 is stored, the link body 3
4 is located on the left side of the figure with the shaft 35 as the center, and the damper 40 connected to the link body 34 is urged to the left side. As a result, the bracket 23 and the lock bar 21 swing counterclockwise around the shaft 26, and the lock bar 21 maintains a horizontal state in which the lock bar 21 is at the same vertical position as the fork 2 in a side view. In this state, when power is applied to the motor 31 and the rod 32 of the power cylinder 30 extends, the link body 34 is urged rightward in the figure about the shaft 35 as shown in FIG. By urging the damper 40 to the right, the bracket 23 swings clockwise about the shaft 26. That is, as shown by the solid line, the lock bar 21 swings clockwise about the shaft 26, and the top surface of the lower deck board of the pallet 6 is pressed or pressed against the bottom surface of the tip of the lock bar 21, The lock bar 21 locks the pallet 6.

On the contrary, by reversing the direction of the voltage applied to the motor 31, the rod 32 of the power cylinder 30 is reversed.
By storing the link body 34, the link body 34 rotates leftward about the shaft 35, and the damper 40 also interlocks leftward.
The bracket 23, that is, the lock bar 21 rotates counterclockwise about the shaft 26 and returns to the horizontal state.

Further, the pallet locking means 20 has a structure shown in FIG.
Further, as shown in FIG. 8, a sensor is provided as a detection means for detecting the operation of each part. Rock bar 2
A magnet (member marked in black in the figure) 42 is provided on the back of the bracket 23 that fixes 1 and a magnetic sensor that outputs a detection signal by turning on (or off) by the magnetic force of the magnet 42. Pallet detection sensor 4
3 and a landing detection sensor 44 are provided respectively. As shown in FIGS. 7A and 7B, the lock bar 21
7 is provided with a pallet detection sensor 43 that is turned on by a magnet 42 when the machine is in a horizontal state.
As shown in (c), a landing detection sensor 44 is provided which is turned on by the magnet 42 when the tip of the lock bar 21 turns downward by a predetermined angle.

FIG. 6 is a block diagram of the control system of the pallet lock means 20. Signals from the pallet detection sensor 43 and the landing detection sensor 44 are input to the control means 45 composed of the MPU, and the control means 45 drives the motor 31 to the normal position. By reversing, the rod 32 of the power cylinder 30 is expanded and contracted to lock and unlock the pallet 6 by the lock bar 21. Further, the entrance detection sensor 28 and the exit detection sensor 29
The signal from the detection signal from is input to the control means 45.

Further, as shown in FIG. 6, a lift detection sensor 51 is provided for detecting that the fork 2 has moved down from the lowest position to a predetermined position of a predetermined height. The output of the sensor 51 is also taken into the control means 45. Here, for example, when the lowermost moving position is when the fork 2 is in contact with the ground, the position 10 cm from the ground is set to the above-mentioned predetermined position.

As a specific example of the lift detection sensor 51, a limit switch is installed at a position 10 cm from the ground, and the contact of the limit switch is turned on when the fork 2 moves down to a position 10 cm from the ground. You can set it to. Further, the lift of the fork 2 may be detected from the driving amount of the lift cylinder that lifts the fork 2, and in this case as well, any sensor that can detect that the fork 2 has moved down to a position 10 cm from the ground is used. It may be a contact type or a non-contact type. Furthermore,
The lift of the fork 2 may be detected from the amount of rotation of the motor that drives the lift cylinder.

By the way, when the fork 2 moves down due to the operation of the lift cylinder, when the control means 45 judges that the fork 2 has moved down to a position 10 cm from the ground based on the output of the lift detection sensor 51, the control means 45 lifts the lift. The operation of the cylinder is stopped to stop the lowering of the fork 2 temporarily, and the motor 31 is controlled to unlock the pallet 6 by the pallet locking means 20 to control the power cylinder 3
0 is driven to rotate the rear end of the lock bar 21 upward. The downward movement stop processing of the fork 2 by the control means 45 as described above corresponds to the stop control means in the present invention, and the lock release processing corresponds to the release control means in the present invention.

Further, as shown in FIG. 6, a downward movement resuming switch 53 is provided as a resuming operation means for resuming the downward movement of the fork 2, and control is performed based on the operation of the switch 53 by the operator. The lowering of the fork 2 is restarted by the means 45. The lower movement of the fork 2 at this time is
Although it is stopped when it reaches the lowermost moving position, in order to eliminate the impact at the time of landing of the pallet 6 during that time, it is controlled so as to move downward more slowly than the normal liftdown speed.

Next, the locking operation of the pallet 6 by the pallet locking means 20 will be described with reference to FIG. 7, and then the unlocking operation will be described. First, FIG.
As shown in (a), when the fork 2 is inserted into the pallet 6 while keeping the lock bar 21 in the horizontal state, as shown in FIG.
The tip of 1 is inserted into the pallet 6. At this time, the lock bar 21 is in a state in which the inclined portion 22 formed on the upper portion thereof projects upward from the upper surface of the fork 2, and the position of the lock bar 21 at this time is referred to as a first position. When the fork 2 is further inserted, the inclined portion 2 of the lock bar 21
When the upper surface of 2 hits the end surface of the upper deck board 6a of the pallet 6, the lock bar 21 inclines downward depending on the inclination angle of the inclined portion 22.

Then, as shown in FIG. 7C, when the entire inclined portion 22 of the lock bar 21 enters the pallet 6, the fork 2 completely enters the pallet 6. The position of the lock bar 21 at this time is referred to as a second position. As the lock bar 21 rotates downward from the first position to the second position, the position of the magnet 42 rotates clockwise from the position of the pallet detection sensor 43. As a result, the output of the pallet detection sensor 43 changes from on to off, and the power cylinder 30 is driven according to this output change.

That is, the pallet detection signal from the pallet detection sensor 43 is input to the control means 45, and at the same time, it is determined by the signals from the input detection sensor 28 and the output detection sensor 29 that the rod 32 of the power cylinder 30 is not output. Then, the control means 45 determines that the rod 32 has not come out (extended). Control means 45 receiving these signals
Rotates the motor 31 forward, for example, to rotate the power cylinder 30.
The rod 32 of the lock bar 2 is extended as described above.
Rotate 1 further down. With the rod 32 of the power cylinder 30 extended, the tip of the lock bar 21 presses or presses the upper surface of the lower deck board 6b of the pallet 6. As a result, the pallet 6 is locked by the lock bar 21. At the same time, the rod 3 of the power cylinder 30
By detecting the signal of the output detection sensor 29 which detects that 2 is output, it is determined that the lock bar 21 has locked the pallet 6, and the motor 31 is stopped. The position of the lock bar 21 at this time is referred to as a third position.

FIG. 7 (d) shows a state in which the fork 2 is lifted after the lock bar 21 is brought into contact with the lower deck board 6b as described above, and the pallet 6 is lifted by the fork 2. . Since the magnet 42 is separated from the pallet detection sensor 43 and the landing detection sensor 44, the pallet detection sensor 43 and the landing detection sensor 44 are turned off, and the control means 45 receives a release signal to be described later by both of these off signals. Until that time, the power cylinder 30 is controlled so that the lock bar 21 keeps the pallet 6 locked. Further, when the fork 2 is inserted into the pallet 6 and is locked by the lock bar 21 after the pallet 6 is detected, and the pallet 6 is lifted by the fork 2 as the fork 2 rises, the damper 40 slightly extends,
The elastic force keeps the lock on the pallet 6.

In this way, the fork 2 is moved to the pallet 6
The magnet 42 provided on the side of the lock bar 21 that swings downwards via the inclined portion 22 when inserted into the pallet swings to detect the pallet 6 by the pallet detection sensor 43, thereby driving the pallet locking means 20. The pallet 6 is automatically locked by the lock bar 21. Therefore, when the operator rides on the pallet 6 to carry out the cargo handling work, the pallet 6 is completely locked by the lock bar 21, so that the pallet 6 is not in an unstable state and the work is performed safely. be able to. Moreover, since the locking operation of the pallet 6 is automatically performed, the operator (worker) does not forget to lock the pallet 6 and can prevent an accident.

Next, the unlocking operation of the pallet locking means 20 will be described. In FIG. 8A, the pallet 6 is locked by the lock bar 21 and the pallet 6 is locked by the fork 2.
It shows a state in which the cargo is being lifted by lifting up. In this state, the lock bar 21 is biased in the direction shown by the arrow in the figure, and the magnet 42 is disengaged from the landing detection sensor 44, so both the landing detection sensor 44 and the pallet detection sensor 43 are in the off state.

Then, as shown in FIG. 8B, when the fork 2 is lowered onto the placing portion 47 such as a shelf or the ground (floor surface) to place the pallet 6, the fork 2 is placed on the upper deck of the pallet 6. By lowering from the ceiling surface of the board 6a, the position of the shaft 26 of the lock bar 21 also moves downward. Therefore, the lock bar 21 is compressed by the damper 40 so that the shaft 2
Rotate counterclockwise about 6 by angle α1. The rotation of the lock bar 21 causes the position of the magnet 42 to rotate to the position of the landing detection sensor 44, and the magnet 4
2, the landing detection sensor 44 is turned on.

The landing detection sensor 44 ON signal and the rod 32 output detection sensor 29 ON signal are input to the control means 45, and the control means 45 reverses the motor 31, for example, to rotate the rod 32 of the power cylinder 30. And the lock bar 21 rotates to a horizontal state as shown in FIG. 8C, whereby the pallet 6 is unlocked. The lock bar 21 is naturally in a horizontal state (unlocked state) when the rod 32 of the power cylinder 30 is stored. When the insertion detection sensor 28 that detects that the rod 32 of the power cylinder 30 has been inserted is turned on, the control means 45 recognizes that the lock is released.

Thus, when the pallet 6 is inserted into the fork 2, the lock bar 21 presses the lower deck board 6b to lock the pallet 6. Then, when the fork 2 is raised thereafter, the upper deck board 6a of the pallet 6 is pressed and supported from the inside of the pallet 6 by the upper surface of the fork 2 and the lower deck board 6b by the lock bar 21, respectively. It is locked more firmly.

Then, the operator restarts the downward movement switch 5
3 is operated, the operation of the lift cylinder is restarted by the control means 45, the downward movement of the fork 2 which has been stopped and controlled is resumed, and when the fork 2 reaches the lowermost movement position,
The operation of the lift cylinder is stopped, the lowering of the fork 2 is completely stopped, the fork 2 is separated from the upper deck board 6a of the pallet 6, and the fork 2 can be easily pulled out from the pallet 6.

Therefore, according to the first embodiment, when the pallet 6 is unlocked, the fork 2 can be pulled out from the pallet 6 without waiting for the pallet 6 to be completely landed. It is not necessary to wait until the pallet 6 is completely landed and then unlocked in order to pull out the pallet 6 as in the conventional case, and it is possible to prevent the work efficiency from being lowered.

Further, the fork 2 is at a predetermined position (1 from the ground).
If the pallet 6 is almost landed or slightly floated from the ground when it is moved down to a position (0 cm), the pallet 6 does not land and the operator remains locked as in the conventional case. It is possible to prevent the fork 2 from being pulled out from the pallet 6 and prevent the load from collapsing or the pallet 6 to be dragged and damaged.

Further, the control means 45 causes the fork 2 to move to a predetermined position (1 from the ground based on the output of the lift detection sensor 51).
When it is determined that the fork 2 has moved down to the 0 cm position), the control means 45 stops the operation of the lift cylinder and temporarily stops the lowering of the fork 2.
By stopping, the operator can easily recognize that the fork 2 has moved down to a predetermined position near the ground. Moreover, if the downward movement restart switch 53 is operated in this state,
The downward movement of the fork 2 can be resumed until the pallet 6 is completely landed.

In the present embodiment, the case where the downward movement resuming switch 53 is provided as the resuming operation means has been described. However, instead of the downward movement resuming switch 53, a lift switch for a normal lift down operation is also used. I do not care.

Further, in this embodiment, the lowering of the fork 2 is stopped when the fork 2 moves down to a predetermined position. It is not necessary to provide the motion restart switch 53 either. In short, at least the lock of the pallet 6 may be automatically released when the fork 2 moves down to a predetermined position.

(Second Embodiment) A second embodiment of the present invention will be described with reference to FIGS. 9 and 10. However, FIG. 9 is a block diagram of the control system, and FIG. 10 is an operation explanatory diagram.
Since the basic configuration of the order picking truck 1 in this embodiment is almost the same as the contents described in the first embodiment, the following description will be made mainly with reference to FIGS. 1 to 3 and mainly different from the first embodiment. The points to do will be described.

In this embodiment, as shown in FIG. 9, a changeover switch 55 as a changeover operation means is provided, and this changeover switch 55 indicates the execution start timing of the lock release control of the pallet 6 by the control means 45. Detection sensor 51
Based on the output of the fork 2 predetermined position (10 cm from the ground
Position), or when the fork 2 reaches the lowermost position based on the operation of the downward movement restart switch 53. Is capable of selecting at which timing the pallet 6 is unlocked, and this point is largely different from the first embodiment.

Then, as shown in the flow chart of FIG. 10, when the pallet 6 is lifted down while the pallet 6 is locked by the pallet lock means 20, the fork is detected by the control means 45 based on the output of the lift detection sensor 51. It is determined whether 2 has moved down to a predetermined position (10 cm from the ground) (S1), and the result of this determination is NO.
If so, this determination is repeated until the determination result becomes YES, and if the determination result becomes YES, the changeover switch 55
Based on the operation of, when the fork 2 moves down to a predetermined position, it is determined whether or not the unlocking of the pallet 6 is immediately started (S2).

If the decision result in the step S2 is YES, the changeover switch 55 is changed over so as to start execution of the unlocking control of the pallet 6 at the time when it is detected that the fork 2 has moved down to the predetermined position. Therefore, the control means 45 immediately controls the motor 31 to drive the power cylinder 30, the rear end of the lock bar 21 is rotated upward, and the pallet 6 is unlocked (S).
3) After that, the operation ends.

On the other hand, if the decision result in the step S2 is NO, the fork 2 is operated based on the operation of the downward movement restart switch 53.
When the fork 2 moves down to the lowermost moving position, the motor 31 is controlled when the fork 2 moves down to the lowermost moving position. The power cylinder 30 is driven, the rear end of the lock bar 21 is rotated upward to unlock the pallet 6 (S4), and then the operation ends.

Therefore, according to the second embodiment, the execution start timing of the lock release control of the pallet 6 is set when the fork 2 moves down to a predetermined position or when the fork 2 reaches the lowest position. The operator can select which one to use, and the lock release timing of the pallet 6 can be selected according to the work situation.

As another embodiment of the present invention, in the first or second embodiment described above, the fork 2 is inserted by the pallet detection sensor 43 which detects that the fork 2 is inserted in the pallet 6. When the desired pallet 6 is not detected, even if the fork 2 moves down to a predetermined position (10 cm from the ground), the control means 45
Therefore, the stop control of the fork 2 may not be performed.

In this way, when the pallet detection sensor 43 does not detect the pallet 6, it is not necessary to perform the stop control of the fork 2 by the control means 45, so the stop control of the fork 2 is not performed, and unnecessary control is omitted. You can

Further, in each of the above-described embodiments, the forklift is explained as the order picking truck 1. However, the forklift to which the present invention can be applied is not particularly limited to the order picking truck.

The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention.

[0065]

As described above, according to the invention described in claim 1, since the lock of the pallet is released by the release control means before the landing of the pallet completely, the fork can be pulled out from the pallet. As described above, it is not necessary to wait for the lock to be released after the pallet is completely landed, and the work efficiency can be reduced.

Further, if the height detected by the lift detection sensor is set to the lowest position, for example, about 10 cm from the ground, the pallet is unlocked when it is almost landed or slightly floated from the ground. Therefore, as in the past,
Even if the pallet is landed, the operator will not pull out the fork from the pallet while the lock is not completely unlocked, and the load will collapse or the pallet will be dragged and damaged. Can be prevented.

According to the second aspect of the present invention, the fork is moved downward while the pallet is locked by the pallet locking means, and the lift detection sensor detects that the fork has moved to a predetermined position. Then, since the stop control means stops the lowering of the fork, the operator can recognize that the fork has moved down to a predetermined position by stopping the fork.

Further, even if the downward movement of the fork is stopped by the stop control means, the downward movement of the fork is resumed by the operation of the resuming operation means, and at the same time, the pallet locking is performed by the release control means based on the operation of the resuming operation means. Since the lock of the pallet is released by the means, the pallet is clamped even at a predetermined low lift position, so that it is possible to prevent the load from collapsing and the pallet from being dragged and damaged. .

According to the third aspect of the invention, the execution start timing of the pallet lock release control by the release control means is set according to the work situation when the fork is moved down to a predetermined position or the fork is moved. It becomes possible for the operator to select one of the positions when the bottom position is reached.

According to the fourth aspect of the invention, when the pallet is not detected by the pallet detection sensor, the stop control means does not need to perform stop control of the fork. It is possible to omit various controls.

According to the invention described in claim 5, it is possible to provide an order picking truck which can automatically unlock the pallet.

[Brief description of drawings]

FIG. 1 is a perspective view of an order picking track according to a first embodiment of the present invention as seen obliquely from the rear.

FIG. 2 is a perspective view of the order picking track according to the first embodiment of the present invention as seen obliquely from the front.

FIG. 3 is a partial plan view of the first embodiment of the present invention.

FIG. 4 is a right side view of another part of the first embodiment of the present invention.

FIG. 5 is a diagram illustrating another part of the operation in the first embodiment of the present invention.

FIG. 6 is a block diagram of a control system in the first embodiment of the present invention.

FIG. 7 is an operation explanatory diagram according to the first embodiment of the present invention.

FIG. 8 is an operation explanatory diagram according to the first embodiment of the present invention.

FIG. 9 is a block diagram of a control system in a second embodiment of the present invention.

FIG. 10 is a flow chart for explaining the operation in the second embodiment of the present invention.

FIG. 11 is a side view of a conventional example.

FIG. 12 is a block diagram of a conventional example.

[Explanation of symbols]

1 Order picking truck Two forks 3 cab 6 pallets 20 Pallet locking means 21 Rock Bar 30 power cylinder 31 motor 43 Pallet detection sensor 45 Control means (release control means, stop control means) 51 Lifting height detection sensor 53 Downward restart switch (restart operation means) 55 Changeover switch (changeover operation means)

Claims (5)

[Claims] 1. A forklift control device comprising pallet lock means for locking a pallet by pressing a lower deck board of the pallet into which the fork is inserted, and a lift for detecting the position of the fork that moves up and down. A detection sensor; and a release control means for releasing and controlling the lock of the pallet by the pallet locking means when it is detected by the lift detection sensor that the fork has moved down to a predetermined position. Forklift control device characterized by being 2. A stop control means for stopping the downward movement of the fork when the downward movement of the fork to the predetermined position is detected by the lift detection sensor, and an operation for restarting the downward movement. The forklift control device according to claim 1, further comprising: a restart operation unit that restarts the downward movement of the fork that is stop-controlled by the stop control unit. 3. The execution start timing of lock release control of the pallet by the release control means when the downward movement of the fork to the predetermined position is detected by the lift detection sensor, or the restart operation means. 3. The forklift control device according to claim 2, further comprising switching operation means for performing switching setting when the fork reaches the lowest position based on the operation of. 4. A pallet detection sensor for detecting that the fork has been inserted into the pallet, wherein the stop control means includes:
The forklift control device according to claim 2, wherein stop control of the fork is not performed when the pallet into which the fork should be inserted is not detected. 5. The control device for a forklift according to claim 1, wherein the forklift is an order picking truck in which a driver's cab is integrally raised and lowered together with the fork.