JP2780014B2 - Transport carriage fork control method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention
It is equipped with two forks to carry out from a shelf of an automatic warehouse and carry it into a predetermined position, so that small loads are carried in and out with one fork, and large loads are carried in and out with two forks. And a method of controlling a fork of a transport carriage.

[0002]

2. Description of the Related Art FIG. 8 is a view showing a structural example of a transport carriage having two forks. As shown in the drawing, the transport carriage 10 includes a carriage frame 11, and a front fork 12 is provided above the carriage frame 11 in a forward direction of the transport carriage 10 and a rear fork 13 in a backward direction. A driving mechanism having a rotating shaft 14 for transmitting the driving force of a driving motor 16 to the rotating shaft 1 and a rotating shaft 1 for transmitting the driving force of a driving motor 17 to the rear fork 13
5 is provided. In addition, 1
Reference numeral 8 denotes a clutch that connects the rotating shafts 14 and 15 of both drive mechanisms. Although not shown, the transport carriage 10 having the above structure is provided on a stacker crane of an automatic warehouse or a traveling cart for carrying in / out a load.

In the transport carriage 10 having the above structure,
Small load W in width direction (running direction of transport carriage 10)
1. When loading / unloading W1, as shown in FIG.
When the clutch 18 is released, the front fork 12 and the rear fork 13 are operated independently of each other, and when loading or unloading a large load W2, the clutch 18 is connected in advance as shown in FIG. The motor 16 and the drive motor 17 are started via separate inverters, respectively, and the front fork 1 is driven.
The second and rear forks 13 were operated independently, and the clutch 18 was released at the time of deceleration, and the front fork 12 and the rear fork 13 were positioned at the respective fork ends or the center.

[0004]

However, the above-described method for carrying in and out the load W2 having a large width has the following disadvantages. (1) When the two motors are driven while the clutch 18 is connected via two separate inverters, the inverter load is offset due to the difference in the fork operating torque of the front fork 12 and the rear fork 13, When an attempt is made to cause a speed difference between the front fork 12 and the rear fork 13, the inverter is likely to be abnormal.

(2) When the clutch 18 is released at the time of deceleration, the load W on the front fork 12 and the rear fork 13
2 plays a role of a clutch, and in this state, when the fork on one side with a light load stops early or at the center, the fork on the side stopped by the operation of the remaining fork is pulled and overruns. , Fork displacement occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a method for controlling a fork of a transport carriage which eliminates the above-mentioned problems and does not cause a fork deviation due to an inverter abnormality or a fork overrun. The purpose is to:

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention comprises two forks which are arranged side by side, carry a load to a predetermined position and carry it out of the predetermined position; Two motors for driving the two motors, two inverters for supplying drive power to the two motors, and two drive mechanisms for transmitting the respective driving forces of the two motors to the forks; And a clutch for connecting the two drive mechanisms, wherein a small load in the width direction is carried in and out by one fork, and a large load in the width direction is carried in and out by two forks. When a large load in the width direction is carried out at a predetermined position, the clutch is released, two inverters are operated, and two motors are started by each of the inverters. Of Each of the forks is independently moved forward, and when each of the forks reaches a predetermined position for lifting the load, the positioning of each of the forks is stopped. Thereafter, the two forks are raised by a predetermined amount, and the clutch is connected during that time. The load is lifted, and then one of the two inverters is operated, the two motors are activated by the one inverter, and the two forks are simultaneously retracted by the two motors, and a predetermined When the positioning is stopped at the position and a large load in the width direction is carried in to a predetermined position, the clutch is connected, one of the two inverters is operated, and two motors are started by the one inverter, The two motors simultaneously move forward the two forks, and when each of the forks reaches a predetermined position where the load is delivered, the two forks are positioned and stopped,
Thereafter, the load is lowered by a predetermined amount, the clutch is released, the two inverters are operated to start the two motors, and the two motors independently drive the two forks. It is characterized by performing control to retreat and stop positioning at a predetermined position.

[0008]

According to the present invention, as described above, when a large load in the width direction is carried out at a predetermined position, the clutch is released and the two motors are activated via the two inverters, respectively. Operate the two forks independently,
When each of the forks reaches the predetermined position for lifting the load, the positioning of each fork is stopped, so that the two forks are aligned at the predetermined position for lifting the load, then the clutch is connected, and the load is raised by raising the two forks. Is normally placed on the two forks. Thereafter, one of the two inverters is operated, two motors are started via the one inverter, and the two forks are simultaneously retracted by the two motors. The inverter load does not shift due to the difference in torque, and the inverter does not become abnormal. Further, when the fork reaches a predetermined position on the transport carriage, the two motors are stopped and both forks are stopped at the same time. There is no overrun and no fork displacement.

Further, when a large load in the width direction is carried into a predetermined position, the clutch is connected, one of the two inverters is operated, and two of the two inverters are operated.
Since two motors are started and two forks are simultaneously operated by the two motors, the inverter load is not biased due to a difference in fork torque, so that the inverter does not become abnormal and the fork reaches the load delivery position. Then, the one inverter is stopped, the two motors are stopped, and both forks are stopped at the same time.
No fork displacement occurs. When each of the forks reaches a predetermined position at which the load is delivered, the two forks are stopped in position, and then the load is lowered by a predetermined amount. Thereafter, the clutches are released to operate the two inverters. The two motors are activated by the two invars, respectively, and the two forks are independently retracted and positioned and stopped at predetermined positions, so that the two forks are aligned at predetermined positions.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. 3 to 5 are views showing the operation of the fork when a load is carried out at a predetermined position according to the fork control method of the present invention, and FIG. 3A is a plan view. Figure (b) is a side view. The structure of the transport carriage of the present invention is the same as that of FIG.

When a large load W2 in the width direction is carried out at the predetermined position, first, as shown in FIG.
, And the two drive motors 16 and 17 are started via the respective inverters, and the two drive motors 16 and 17 are started.
Then, the front fork 12 and the rear fork 13 are independently advanced as shown by dotted lines. When the front fork 12 and the rear fork 13 reach the predetermined positions for lifting the load W2, the positioning stops. This allows the front fork 12
And the rear fork 13 are aligned and stopped at a predetermined position.

Thereafter, as shown by a dotted line in FIG. 4, the front fork 12 and the rear fork 13 are simultaneously raised by a predetermined amount (actually, the carriage 10 is raised) to lift the load W2.
In the meantime, the clutch 18 is connected, two drive motors 16 and 17 are started via one inverter, and the front fork 12 and the rear fork 1 are driven by the two drive motors 16 and 17.
The two forks 3 are simultaneously retracted to the positions shown by the dotted lines in FIG. 5, and the positioning is stopped at a predetermined position (center position) of the carriage 10.

Although not shown when the load W2 is carried into a predetermined position, the clutch 18 is connected, and one drive activates the two drive motors 16 and 17 so that the two drive motors 16 and 17 are activated. The front fork 12 and rear fork 13
The forks 12 and 13 are simultaneously moved forward, and when the front and rear forks 12 and 13 reach a predetermined position where the load W2 is delivered, the forks 12 and 13 are positioned and stopped.
Is lowered by a predetermined amount, the clutch 18 is released and the two drive motors 16 and 17 are activated via separate inverters.
At 7, the forks of the front fork 12 and the rear fork 13 are respectively independently retracted and stopped at a predetermined position (center position) of the carriage 10.

FIG. 6 is a diagram showing a fork drive circuit for implementing the fork control method of the transport carriage. N
FB1 and NFB2 are no-fuse breakers and I
n1 and In2 are inverters, Mg1, Mg2,
Mg3 and Mg4 are electromagnetic switches respectively, 16 is a drive motor for a front fork, 17 is a drive motor for a rear fork,
19 is a running motor.

FIG. 7 is a diagram showing the position of the fork and the arrangement of each sensor. As shown in the figure, a front fork left end limit switch LS1 is arranged at the front fork left end position, a front fork center zone sensor PH is arranged at the front fork center position, and a front fork right end limit switch LS2 is arranged at the front fork right end position. A rear fork left end limit switch LS5 is disposed at the rear fork left end position, a rear fork left center limit switch LS3 and a rear fork right center limit switch LS4 are disposed at the rear fork center position, and a rear fork right end limit switch LS6 is disposed at the rear fork right end position. You. And the respective limit switches LS1 to LS
S6 and sensor PH are front fork 12, rear fork 13
Activated when has reached that position.

Next, the fork control operation of the transport carriage of the present invention will be described in detail with reference to FIGS. 1 and 2 and with reference to FIGS. FIG. 1 is a diagram showing a flow of an operation of unloading a large load W2. First, the clutch 18 is released (step ST1). The release of the clutch 18 is a release confirmation operation of the clutch 18 when the clutch 18 is already released. Next, the electromagnetic switch Mg1,
Mg3 is released (step ST2), and the electromagnetic switch Mg is released.
2. Inject Mg4 (step ST3). Subsequently, the inverters In1 and In2 are operated (step ST4), and the drive motors 17 and 16 are activated by the two inverters In1 and In2, respectively. As a result, the rear fork 13 and the front fork 12 independently move forward.

The rear fork left end limit switch LS5 operates to determine whether the rear fork 13 has reached the left end position (step ST5).
n1 is stopped (step ST6), and at the same time, the front fork left end limit switch LS1 is operated, and the front fork 1
2 is determined to have reached the left end position (step ST
7) If yes, stop inverter In2 (step ST8). Then, the front and rear forks 12, 13
Are determined to have reached the leftmost position (step ST
9) If yes, the front and rear forks 12, 13 are raised (actually, the transport carriage 10 is raised) (step ST10).

During the ascent, the clutch 18 is engaged (step ST11), the electromagnetic switch Mg4 is opened (step ST12), and the electromagnetic switch Mg3 is turned on (step ST13). It is confirmed that the front and rear forks 12, 13 have reached the upper level (step ST14), and the ascent / descent is stopped (step ST15). Next, the inverter In1 is operated (step ST16), and the one inverter In1 is operated.
To start the two drive motors 16 and 17, and simultaneously retreat the front and rear forks 12 and 13.

Subsequently, the rear fork right center limit switch LS4 is operated, and the rear fork 13 is moved to the transport carriage 1.
0 (Step ST17), stops the inverter In1 (Step ST18), activates the front fork central zone sensor PH, and confirms that the front fork 12 has reached the central zone (Step ST17). ST1
9), the unloading operation is completed. If the front fork 12 does not reach the central zone in step ST19, it is determined that the fork sensor is abnormal (step ST20), and abnormal processing is performed (step ST21).

FIG. 2 is a diagram showing a flow of an operation of loading a large load W2. First, the clutch 18 is engaged (step ST31). The connection of the clutch 18 is a connection confirmation operation of the clutch 18 when the clutch 18 is already connected. Subsequently, the electromagnetic switches Mg1, Mg4
Is opened (step ST32), and the electromagnetic switches Mg2, M
g3 (step ST33), and the inverter In1
Is driven (step ST34). Thereby, the two drive motors 16 and 17 are simultaneously activated by one inverter In1, and the forks 12 and 13 loaded with the load are simultaneously advanced.

It is confirmed that the rear fork left end limit switch LS5 is operated and the rear fork 13 has reached the rear fork left end position (step ST35).
Is stopped (step ST36). Next, the front and rear forks 12, 13 are lowered (actually, the transport carriage 10 is lowered) (step ST37). During this downward movement, the clutch 18 is released (step ST38), and the electromagnetic switch Mg3 is released.
Is opened (step ST39), and the electromagnetic switch Mg4 is turned on (step ST40). Front and rear forks 12, 13
Has reached the lower level (step ST4).
1), lifting is stopped (step ST42).

Subsequently, the inverters In1 and In2 are operated (step ST43). Thereby, the drive motor 17,
Each of 16 is activated by each of the inverters In1 and In2, and causes the rear fork 13 and the front fork 12 to retreat independently by the drive motors 17 and 16, respectively. Next, the rear fork right center limit switch LS4 is operated, and it is confirmed that the rear fork 13 has reached the center of the carriage 10 (step ST44).
(Step ST45), the front fork center zone sensor PH is activated, and it is confirmed that the front fork 12 has reached the center zone (Step ST46), and the inverter In2 is stopped (Step ST47). It is confirmed that the rear front forks 13 and 12 are at the center of the carriage 10 (step ST48), and the loading of the load W2 is completed.

The operations shown in FIG. 1 and FIG. 2 are performed by an arithmetic processing unit such as a microcomputer provided in a control unit (not shown) to transmit various data such as output signals of the limit switches LS1 to LS6 and the front fork central zone sensor PH. Executed with reference.

In the above embodiment, the front and rear forks 12,
13 has been described as moving to the left, it is of course possible to move to the right, in which case the front fork right end limit switch LS2 and the rear fork right end limit switch L
S6, referring to the output signals of the rear fork left center limit switch LS3 and the front fork center zone sensor PH.

[0025]

As described above, according to the present invention,
In a transport carriage having two forks, an excellent effect of being able to provide a fork control method that does not cause a fork deviation due to an inverter abnormality or a fork overrun is obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a flow of an operation of carrying out a wide load in a fork control method of the present invention.

FIG. 2 is a diagram showing a flow of an operation of loading a wide load in the fork control method of the present invention.

FIG. 3 is a diagram showing an operation of a fork when a load is carried out at a predetermined position in the fork control method of the present invention, and FIG.
Is a plan view, and FIG. 2B is a side view.

FIG. 4 is a view showing an operation of a fork when a load is carried out at a predetermined position according to the fork control method of the present invention, and FIG.
Is a plan view, and FIG. 2B is a side view.

FIG. 5 is a diagram showing an operation of a fork when a load is carried out at a predetermined position according to the fork control method of the present invention, and FIG.
Is a plan view, and FIG. 2B is a side view.

FIG. 6 is a diagram showing a fork drive circuit.

FIG. 7 is a diagram showing a fork position and each sensor arrangement.

FIGS. 8A and 8B are diagrams showing an example of the structure of a transport carriage having two forks. FIG. 8A shows the case of loading and unloading a narrow load, and FIG. 8B shows the loading and unloading of a narrow load. Are shown below.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Conveyance carriage 11 Carriage frame 12 Front fork 13 Rear fork 14 Rotation shaft 15 Rotation shaft 16 Drive motor 17 Drive motor 18 Clutch 19 Travel motor

Claims (1)

(57) [Claims] 1. Two forks arranged side by side for carrying a load to a predetermined position and discharging the load from the predetermined position;
Two motors for driving each of the two forks, two inverters for supplying driving power to the two motors, and a drive 2 for transmitting the driving force of each of the two motors to each of the forks. It has a drive mechanism and a clutch for connecting the two drive mechanisms, and a small load in the width direction is carried in and out by one fork, and a large load in the width direction is carried in and out by the two forks. A method for controlling a fork of a transport carriage, wherein when a large load in the width direction is carried out from the predetermined position, the clutch is released, the two inverters are operated, and the two motors are respectively activated by the inverters. At the same time, the two forks are independently advanced by the two motors, and when each of the forks reaches a predetermined position for lifting the load, the forks are positioned and stopped. Stop, and then raise the two forks by a predetermined amount, connect the clutch in the meantime, lift the load, and then operate one of the two inverters. When the two motors are started, the two motors simultaneously retract the two forks, stop the positioning at a predetermined position, and connect the clutch when carrying a large load in the width direction to the predetermined position. Operating one of the two inverters, starting the two motors with the one inverter,
The two motors simultaneously advance the two forks, and when each of the forks reaches a predetermined position for transferring the load, stop positioning the two forks, and then lower the predetermined amount for transferring the load, In the meantime, the clutch is released, and then the two inverters are operated to start the two motors respectively with the inverters, and the two motors independently retract the two forks, respectively. And controlling to stop the positioning at a predetermined position.