JPH0229599B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fork lifting device.

Conventionally, when lifting a fork to a predetermined lifting height position for loading or unloading in an unmanned forklift, the lifting height position is stored in advance in a storage device and the lifting height data stored in the storage device is used. The height of the fork was now controlled.

However, there is no problem when loading and unloading the same load and at the same location, but if the size of the load changes or the height of the loading platform changes, the data will be stored in the storage device. It was not possible to raise the fork based on the data obtained. In such cases, the data must be changed or the program must be changed each time, and there is a problem in that the data cannot be easily corrected.

This invention was made in order to solve the above-mentioned problems, and its purpose is to adjust the fork lift height at any time according to changes in the height of the cargo, the height of the receiving platform, or the height of the shipping platform. The object of the present invention is to provide a fork lifting device that allows data to be easily and easily set.

An embodiment of a fork lifting device for an unmanned forklift embodying the present invention will be described below with reference to the drawings.

In FIG. 1, a body frame 2 of an unmanned forklift 1 is connected to an outer mast 4 via a bearing tube (not shown) attached to the axle of a front wheel 3 on the front side.
is supported so that it can tilt forward and backward. The tail cylinder 5 has its base end rotatably connected to the front upper surface of the vehicle body frame 2, and the tip of the piston rod 5a of the tail cylinder 5 is rotatably connected to the outer surface of the outer mast 4. has been done. Therefore, when the piston rod 5a of the tail cylinder 5 is retracted when the outer mast 4 is in the vertical position shown in FIG.
is tilted to the rear position, and conversely, when the piston rod 5a is moved forward, the outer mast 4 is tilted forward.

The lift cylinder 7 is fixedly installed inside the rear part of the outer mast 4, and the tip of the piston rod 7a is attached to the inner mast 8, which is attached to the inside of the outer mast 4 so as to be movable up and down, as shown in FIGS. 2 and 3. It is fitted and fixed to a connecting member 9 fixedly provided on the upper part of the rear surface. As shown in FIG. 2, inside the inner mast 8, a lift bracket 10 is mounted so as to be movable up and down by a pair of upper and lower rollers 11. 14
is attached.

Further, as shown in FIG. 3, a mounting block 15 is fixed to the rear surface of the inner mast 8 between the connecting member 9 and the upper tie beam 8a of the inner mast 8, and a chain wheel 16 is attached to this block 15 as a support shaft. It is rotatably supported by 17. The mounting bracket 18 attached to the upper part of the lift cylinder 7 and the lift bracket 1
Both ends of the lift chain 20 are connected to mounting fittings 19 attached to the rear edge of the lift chain 20, and the intermediate portion is hung on the chain wheel 16.

Therefore, when the piston rod 7a of the lift cylinder 7 is driven in the vertical direction, the inner mast 8 and the chain wheel 16 are moved up and down, and the fork 14 is moved twice as much as the inner mast 8 via the lift chain 20. Moves up and down at speed. At this time, the chain wheel 16 is rotated in proportion to the amount of movement of the lift chain 20, that is, the amount of movement of the fork 14.

In FIG. 3, a support arm 21 is fixed to the rear surface of the inner mast 8, and a lifting height detection device 22 consisting of a rotary encoder is attached to the tip attachment portion 21a of the support arm 21. The input shaft 22a of this lifting height detection device 22 is connected to the chain wheel 1.
6 and said lift cylinder 7
As a result, the fork 14 is moved up and down, and the chain wheel 16 is rotated forward and backward in proportion to this movement. On the other hand, in conjunction with this, the input shaft 2 of the lift height detection device 22
2a is also reversed. And this input shaft 22a
The lifting height detecting device 22 outputs a signal for detecting the lifting amount and lifting height position of the fork 14 based on the rotating direction and rotating amount.

A micro switch 23 is attached to the lower end of the outer mast 4, as shown by the broken line in FIG. The micro switch 23 is turned on. In this embodiment, fork 14
When the robot reaches a height position of 30 cm (height position in running posture), the dock 24 is activated by the micro switch 23.
is turned on, and the micro switch 23 outputs an on signal.

As shown in FIG. 1, on the outer surface of the outer mast 4, first and second stage number sensors 26 and 27, each of which serves as a load detection sensor and is comprised of a light emitting diode and a phototransistor, are adjustable in angle toward the front and upward. installed on. Of the loads W1, W2, and W3 loaded in front, 2
The presence or absence of the same cargoes W2 and W3 is detected by irradiating light onto the cargoes W2 and W3 in the third and third tiers and receiving the reflected light with a phototransistor.

In addition, a front distance sensor 28 consisting of a light emitting diode and a phototransistor is provided at the center position of the lower front side of the vehicle body frame 2, as shown by the broken line in FIG. is now being detected.

In this embodiment, a receiving coil 29 and a transmitting coil 30 are provided on the lower surface of the vehicle body frame 2, and the receiving coil 29 is a station coil (not shown) disposed on the traveling path of the forklift.
The transmitting coil 30 receives various command signals transmitted from the ground station control device installed in the control room through the station coil, and transmits various command signals to the ground station control device through the same station coil. It is beginning to be transmitted. A pick-up coil (not shown) for detecting a track line placed on the travel path at a predetermined position on the lower surface of the vehicle body frame 2
are provided, and the unmanned forklift 1 can travel on the travel path based on the detection of these pickup coils.

Next, the electric circuit of the fork lifting device of the unmanned forklift will be explained.

In FIG. 4, a fork lift control circuit 31 receives a command signal SG1 from the ground station control device via an interface 32. Same signal SG1
In response to this, the fork elevation control circuit 31 executes arithmetic processing operations for the elevation control of the fork 14 according to a preset program. The fork lift control circuit 31 receives the on signal from the micro switch 23 and the detection signal from the lift height detection device 22 through the interface 32.
Input via . When the fork lift control circuit 31 receives the ON signal, it sets the content of the counter built in the control circuit 31 to 30 (meaning the lift height value of the fork 14 is 30 cm), and at the same time sets the content of the counter built in the control circuit 31 to 30 (meaning the lift height value of the fork 14 is 30 cm). The fork 14 adds or subtracts the contents of the counter based on the detection signal of
Calculate the lift height position.

Further, the fork elevation control circuit 31 includes the first and second step number sensors 26 and 27 and the front distance sensor 2.
A detection signal from 8 is input via the interface 32. Based on these signals, the control circuit 31 determines the presence or absence of the loads W1, W2, W3 and the number of loads.

The cargo height setting device 33, the receiving platform height setting device 34, and the shipping platform height setting device 35 are each constituted by a digital switch in this embodiment, and are provided at predetermined positions of the unmanned forklift 1. The cargo height setting device 33 is for setting the height H1 for one piece of cargo, including the height of the pallet P.
Data on the height H1 is output to the first gate circuit 36. The receiving platform height setting device 34 sets the receiving platform height H2 provided at the cargo loading position during cargo loading work.
The height H2 data is output to the second gate circuit 37. The shipping platform height setter 35 is used to set the height H3 of the shipping platform provided at the loading position during loading operation, and transmits the data of the same height H3 to the third gate circuit 3.
Output to 8.

First, second, third gate circuits 36, 37, 3
Reference numeral 8 is configured to receive an on signal from the fork lift control circuit 31 via an interface 32, and the heights are outputted from each of the setting devices 33, 34, and 35 based on the on signal. The data of H1, H2, and H3 are outputted to the fork control circuit 31 via the interface 32.

Then, when the fork lift control circuit 31 receives the data of the cargo height H1 from the cargo height setting device 33 via the first gate circuit 36, the data and the first and second stage number sensors 26, 27 and the number of loads based on the detection signal from the front distance sensor 28, the lift height value H of the fork 14 for loading or unloading is calculated. Also, when the control circuit 31 inputs the gator of the receiving platform height H2 from the receiving platform height setting device 34 via the second gate circuit 37, it determines the lifting height value of the fork 14 when loading the cargo on the receiving platform. Calculate H. Also, the same control circuit 31
is the lift height value of the fork 14 when picking up the cargo placed on the shipping platform when the data of the receiving platform height H3 from the shipping platform height setter 35 is inputted via the third gate circuit 38. Calculate the value of H.

Then, the fork lift control circuit 31 sends a fork lift drive control signal to the lift cylinder drive circuit 39 in order to raise the fork 14 to the calculated lift height value H, that is, to drive the lift cylinder 7.
Output to. The drive circuit 39 drives the lift cylinder 7 in response to the signal to raise the fork 14 to a lifting height H.

Next, the operation of the fork lifting device in the unmanned forklift constructed as described above will be explained.

First, as shown in Figure 1, the load W is loaded in three tiers.
A case will be described in which the cargo picking operations 1, W2, and W3 are performed. Now, the command signal from the ground station controller
When the unmanned forklift 1 reaches a position in front of the loads W1, W2, W3 and stops based on the SG1, as shown in FIG. Detect loads W1, W2, and W3. Each sensor 2
Based on the detection signals 6, 27, and 28, the fork control circuit 31 determines that the loads W1, W2, and W3 are stacked in three stages.

Meanwhile, at the same time, the fork lift control circuit 31 operates the interface 32 based on the command signal SG1, that is, based on the command to carry out the cargo picking operation.
An on signal is output to the first gate circuit 36 via the baggage height setting device 33, and data on the baggage height H1 from the baggage height setting device 33 is input. The control circuit 31 determines a lifting height value for lifting the fork 14 to the insertion position of the third tier pallet P based on the data of the cargo height H1 and the fact that the cargoes W1, W2, and W3 are stacked in three tiers. H
Perform the calculation (=H1×2). Next, after setting the calculation result in a register provided in the fork lift control circuit 31, the control circuit outputs a drive control signal to the lift cylinder drive circuit 39 in order to lift the fork 14 to the lift height value.

The lift cylinder drive circuit 39 drives the lift cylinder 7 to raise the fork 14 in response to this drive control signal.

At the same time as the fork rises, a detection signal is input from the lift height detection device 22 to the fork lift control circuit 31 via the interface 32. Based on this detection signal, a counter in the fork elevation control circuit 31 performs a counting operation to count the elevation position of the fork 14 at that time.
Then, the fork lift control circuit 31 sends a lift cylinder drive circuit 39 to stop the fork 14 when the contents of the counter match the contents of the register, that is, when the fork 14 reaches the insertion position of the third pallet P. A drive control signal for stopping the fork 14 is output. The lift cylinder drive circuit 39 immediately stops driving the lift cylinder 7 in response to this signal.

Next, when the third stage load W3 has been picked up and the second stage load W2 is to be picked up, the second stage number sensor 27 does not output a detection signal, so the fork lift control circuit 31 Based on the detection signals from the first stage number sensor 26 and the front distance sensor 28, it is determined that the loads W1 and W2 are stacked on two stages. Based on the height H1 data and the fact that the loads W1 and W2 are stacked in two stages, the control circuit 31 determines the lifting height H (=H1× Perform the operation result of 1) and set it in the register in the same way as above. Similarly to the above, the fork lift control circuit 31 outputs a drive control signal to the lift cylinder drive circuit 39 to lift the fork 14 to its lifting height and then stop it.

In this way, in this embodiment, the luggage height setting device 33
The data of the cargo height H1 set in and the first and second
Based on the detection signals of the stage number sensors 26 and 27,
The fork 14 can be immediately raised to a raised position for picking up cargo. Furthermore, when the height of the cargo is changed, the fork lift control circuit 31 calculates the fork lift height position based on the height data and adjusts it using the cargo height setting device 33.
4 is designed to raise the height of the cargo height H1. Therefore, when carrying out cargo picking operations with various cargo heights, it is easy to do so by simply changing the height data H1 using the cargo height setting device 33. fork 1
4 can be lifted to a predetermined lifting height position.

In this embodiment, the case of cargo unloading work has been explained, but in the case of cargo loading work, the data of the cargo height H1 of the cargo height setting device 33 and the first
Based on the detection signals from the second stage number sensors 26 and 27, the fork lift control circuit 31 calculates the lift height position at the fork storage position, and sends a drive control signal to the lift cylinder drive circuit 39 based on the calculation result. Output. Therefore, similarly to the above, the fork 14 is accurately and reliably lifted to the lifted position for loading cargo.

Also, when storing cargo on a predetermined loading platform,
In addition, when picking up a load from a predetermined shipping platform, the fork lift control circuit 3
1 outputs an ON signal to the second or third gate circuit 37, 38 based on the command signal SG1, and sets the height H2 from the receiving table height setter 34 or the shipping table height setter 35, Or output H3 data. Based on these data, the fork lift control circuit 31 drives the lift cylinder drive circuit 39 to lift the fork to a high position for depositing the cargo on the receiving platform or to a high position for picking up the cargo from the shipping platform. Outputs a control signal.

In this case, even if the height of the receiving platform or the height of the shipping platform is changed, the loading platform height setter 34 and the shipping platform height setter 35 are used, respectively.
By adjusting the data of the receiving platform height H1 and the data of the shipping platform height H3 respectively, the lifting height position of the fork 14 for loading or unloading can be easily adjusted in the same manner as described above. Can be changed and controlled.

Note that the present invention is not limited to the above-described embodiment; for example, digital switches are used for each of the baggage height setting device 33, the receiving platform height setting device 34, and the shipping platform height setting device 35, but instead of this, digital switches may be used. It may also be implemented by changing to a rotary switch or other data setting device.

As described in detail above, the present invention includes a cargo height setting device, a receiving platform height setting device, and a shipping platform height setting device that can change and set the lifting height of the fork as appropriate, and based on the height setting device. Since the fork is lifted to a predetermined lifting height position based on the output data, even if the height of the cargo, the height of the receiving platform, or the height of the shipping platform changes, the height setting device By simply modifying the height data individually, the fork can be automatically raised to an optimal lifting height position in accordance with the changes. Also, the height of the luggage,
Since a height setting device is provided according to changing factors such as the height of the receiving table and the height of the shipping table, the height can be easily set as appropriate.

In addition, since the tier sensor is placed diagonally above and in front of the outer mast, there is no need to judge the presence or absence of a load when the inner mast is raised compared to a case where the tier sensor is placed on the inner mast. , it is possible to significantly shorten the work cycle of unmanned forklifts and improve work efficiency.

[Brief explanation of drawings]

Fig. 1 is a side view of an unmanned forklift embodying the present invention, Fig. 2 is a side sectional view showing the fork installation state, Fig. 3 is an enlarged front view showing the installation state of the lifting height detection device, and Fig. 4 The figure is an electrical block circuit diagram of the fork lifting device. Unmanned forklift...1. Lift cylinder...
...7, Fork...14, Lift height detection device...2
2. Micro switch...23, First and second stage sensor...26, 27, Direction sensor...2
8. Fork lift control circuit...31, Cargo height setting device...33, Receiving platform height setting device...34, Shipping platform height setting device...35, First, second, third gate circuits ...36, 37, 38, lift cylinder drive circuit...39.

Claims (1)

[Scope of Claims] 1. A lift cylinder drive circuit that drives and controls a lift cylinder that moves the fork up and down, and first and second cylinders that are respectively provided above and below the outer mast and are oriented diagonally upward forward. , a lifting height detection device that detects the lifting height position of the fork, a cargo height setting device that can change and set the cargo height data as appropriate, and a receiving platform height that can change and set the receiving platform height data as appropriate. A setting device, a shipping platform height setting device that can change and set the shipping platform height data as appropriate, and a shipping platform height setting device that determines the number of stages of cargo based on the detection results of each of the above-mentioned tier number sensors at the time of arrival, and uses the determination result and the loading platform height. A predetermined fork lifting height position is calculated based on the receiving table height data of the cargo height setting device and the cargo height data from the cargo height setting device, and at the time of shipment, the cargo height is A predetermined fork lifting height position is calculated based on the determination result, the shipping platform height data from the shipping platform height setting device, and the cargo height data from the cargo height setting device. , a fork elevation control that compares the calculated lifting height position with detection data from the lifting height detection device and outputs a drive control signal to the lift cylinder drive circuit for raising the fork to the same lifting height position; A fork lifting device consisting of a circuit and.