JP4318167B2 - Forklift cargo handling assist device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides a forklift loading assist for controlling the forklift so that the loading fork of the forklift is straight with respect to the load when the three-way stacker forklift places the load N on the fixed station or picks up the load from the fixed station. Relates to the device.
[0002]
[Prior art]
A technique in which a forklift type automatic guided vehicle travels autonomously while detecting a guide wire embedded in a floor surface of an automatic warehouse or the like is well known. As shown in FIG. 6, a watch pointed at an arrow R by an unmanned transport vehicle V traveling upward in the drawing along the guide line Y at a location where guide lines X and Y extending vertically and horizontally intersect. It may turn 90 ° around and turn around. Immediately after this turn, the automated guided vehicle V does not necessarily travel straight along the guide line X exactly. This is because the trajectory in which the automatic guided vehicle V actually turns is somewhat out of order with respect to the steering control of the wheel T based on the program due to the slight slip of the wheel T and the slight unevenness of the floor surface.
[0003]
For this reason, when there is a fixed station S1 immediately after turning, an unmanned transport vehicle is used when carrying a cargo handling operation such as placing the cargo N on the stationary station S1 or scooping up the cargo N existing here with the cargo fork F. The cargo handling fork F of V may not go straight to the luggage N of the fixed station S1. Therefore, immediately before carrying out the cargo handling work, attempts have been made to correct the posture of the automated guided vehicle V by retreating it or to shift the cargo handling fork F in the vehicle width direction. Techniques relating to this are disclosed in the following patent documents.
[0004]
[Patent Document 1]
Japanese Patent Laid-Open No. 2003-63790 [0005]
[Problems to be solved by the invention]
However, temporarily retracting the automatic guided vehicle V is time consuming. In addition, as described above, it is possible to make the cargo handling fork F coincide with the position of the load N only by shifting the load handling fork F in the vehicle width direction. I can't do it.
[0006]
Furthermore, when the fixed station S2 is located on the side of the automatic guided vehicle V immediately after turning, the automatic guided vehicle V is inclined with respect to the fixed station S2. If the automatic guided vehicle V is a three-way stacker forklift, the cargo handling fork F is turned 90 ° (rotating operation), and then the cargo handling fork F is advanced (shifted) toward the fixed station S2. If the cargo handling operation is performed as it is, the cargo N is placed obliquely at the fixed station S2 as illustrated, or the cargo N placed at the stationary station S2 cannot be picked up by the cargo handling fork F. The above problem is remarkable immediately after the turn, but the same thing occurs due to the unevenness of the floor surface even in the automatic guided vehicle V that continues straight along the guide line X.
[0007]
An object of the present invention is to provide a cargo handling assist device capable of correcting the attitude of a cargo handling fork so as to cancel the deviation of the attitude of the automatic guided vehicle.
[0008]
[Means for Solving the Problems]
According to the present invention, a mast is raised on a chassis that is guided by a guide line and autonomously travels, and an elevating carriage that is supported by the mast so as to freely move up and down rotates the cargo handling fork with respect to the chassis. Is a forklift loading assist device that allows the fork tip of the loading fork to reach a loading position defined on the side of the chassis by shifting the vehicle in the vehicle width direction. A chassis direction detecting means for detecting a tilt angle that tilts, a rotation angle detecting means for detecting a turning angle at which the cargo fork is turned with respect to the chassis, and a shift distance of the lifting carriage in the vehicle width direction. a shift amount detection means for detecting, to cancel out the inclination angle of the chassis, which is detected by the undercarriage direction detecting means, based on said inclination angle of said chassis Information useful calculates the origin position of the fork tips of the fork, and calculates a shift distance of the cargo handling fork of the turning angle and the elevation carriage required to move the fork tip of the cargo handling fork to the handling position from the home position Processing means; and control means for controlling the rotation operation and the shift operation of the cargo handling fork according to the turning angle calculated by the information processing means and the shift distance;
It is characterized by providing.
[0009]
In the cargo handling assist device according to the present invention, the chassis direction detection means may be two magnetic guide sensors that are arranged respectively in front of and behind the chassis and detect a relative position of the guide line in the vehicle width direction. Further, the rotation angle detection means and the shift amount detection means may be encoders that code the turning angle of the cargo handling fork and the shift distance of the lifting carriage, respectively.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIGS. 1 and 2, the forklift 1 according to the present embodiment is configured such that a mast 3 is raised on a chassis 2 of an automatic guided vehicle that is guided by a guide line X and autonomously travels, and can be raised and lowered to the mast 3. The supported lifting / lowering carriage 4 is placed on the chassis 2 such that the cargo handling fork 6 with the fork tip 5 protruding forward in the traveling direction of the chassis 2 is directed toward the vehicle width direction of the chassis 2 indicated by the arrow W. The fork tip 5 of the cargo handling fork 6 is made to reach the cargo handling position determined on the side of the chassis 2 by performing a rotation operation for turning the cargo fork 6 and shifting the cargo handling fork 6 in the vehicle width direction. It is.
[0011]
A cargo handling assisting device 10 schematically shown in FIG. 3 is mounted on the forklift 1. The features thereof are chassis direction detection means 7 and 8 for detecting an inclination angle θ at which the chassis 2 is inclined with respect to the guide line X, and a rotation that detects the turning angle at which the cargo fork 6 is turned in the vehicle width direction. An angle detection means 9; a shift amount detection means 11 for detecting a shift distance of the elevating carriage 4 in the vehicle width direction; an information processing means 12 for calculating a turning angle of the cargo handling fork 6 and a shift distance of the elevating carriage 4; The control means 13 and 14 for controlling the rotation operation of the fork 6 and the shift operation of the cargo handling fork 6 are provided.
[0012]
The forklift 1 shown in FIG. 4 is a three-way stacker forklift. The mast 3 is provided with a hydraulic cylinder not shown in the drawing in order to raise and lower the elevating carriage 4. The elevating carriage 4 includes a base plate 41 having two rack gears 40 fixed in a horizontal posture on the front surface, and a main body portion 42 for supporting the cargo handling fork 6. The main body 42 has two drive sources such as a hydraulic motor not shown in the figure, and a pinion that meshes with the rack gear 40 is provided in one of the drive sources, and the rack gear 40 is driven by driving the pinion. It moves (shifts) with the cargo handling fork 6 along. The other drive source rotates a rotating shaft e coupled to the base of the cargo handling fork 6 to turn the cargo handling fork 6 with respect to the chassis 2.
[0013]
The rotation axis e is a fulcrum about which the cargo handling fork 6 turns. The middle point of each of the fork tips 5 of the two cargo handling forks 6 is indicated by the symbol f in the figure. In the following description, the direction from the rotation axis e to the midpoint f is the direction of the cargo handling fork 6. Further, since the interval between the two cargo handling forks 6 is an arbitrarily determined matter, this interval is ignored and the positions of the two fork tips 5 are identified with the midpoint f.
[0014]
The information processing means 12 is mainly composed of a CPU and a memory unit as shown in FIG. The memory unit records a control program that can be read by the CPU in a timely manner, and further records a stop position of the chassis 2 arbitrarily determined on the guide line X and a coordinate value of the cargo handling position related to the cargo handling fork 6 as a database. Is. This cargo handling position coincides with the midpoint f in FIG.
[0015]
For example, in the case of placing a load N in a loaded state on a pallet (not shown) in a fixed station S installed on the side of the guide wire X, the pallet or load N supported by the cargo handling fork 6 So as not to protrude from the fixed station S, the cargo handling fork 6 is protruded to the side of the chassis 2. Alternatively, if the load N is already placed in the fixed station S, the fork tip 5 reaches the back of the pallet or the load fork 6 is moved to the side of the chassis 2 until the fork tip 5 passes through the pallet. Stick out. The position of the fork tip 5 of the cargo handling fork 6 in such a state is the cargo handling position. This position is substantially constant regardless of the position or posture of the chassis 2.
[0016]
The chassis direction detecting means 7 and 8 are two magnetic guide sensors respectively disposed at the front and rear portions of the chassis 2 with a predetermined interval in the direction (front and rear) in which the chassis 2 travels. Although these are well-known techniques and are not shown in the figure, a plurality of induction coils are arranged in a row in the vehicle width direction, and one of the plurality of induction coils is one of the induction wires X located immediately below it. By detecting a magnetic field formed in the surroundings, a detection signal is sent as a predetermined voltage. The other induction coils that do not detect the magnetic field are in an off state without sending a detection signal.
[0017]
Since the voltage value of the detection signal when each induction coil detects the induction wire X is set differently, the information processing means determines which induction coil detects the induction wire X by this voltage value. 12 can be discriminated. Accordingly, since the position where the chassis direction detecting means 7 and 8 are attached to the chassis 2 is determined from the beginning, which of the induction coils of the chassis direction detecting means 7 and 8 detects the induction wire X. Based on this, the information processing means 12 can calculate the inclination angle θ of the chassis 2.
[0018]
Since the rotate angle detection means 9 and the shift amount detection means 11 are both well-known techniques and are not specifically shown, they encode and output the displacement of the fork tip 5. For example, the rotate angle detecting means 9 is an encoder that detects the angle at which the cargo handling fork 6 turns and transmits it to the information processing means 12. The shift amount detection means 11 is an encoder that detects the distance that the fork tip 5 has moved in accordance with the shift operation of the cargo handling fork 6 and transmits it to the information processing means 12.
[0019]
The control means 13, 14 are solenoid valves that open and close based on commands from the information processing means 12, and increase / decrease or block the hydraulic pressure supplied to the drive source described as the explanation of the lift carriage 4. Further, the information processing means 12 may directly control driving or stopping of the pump motor 15 that generates hydraulic pressure.
[0020]
Next, control of the cargo handling assistance device 10 based on the calculation of the information processing means 12 will be described with reference to FIGS. 1 to 3.
[0021]
That is, the position of the fork tip 5 protruding forward in the traveling direction from the lifting carriage 4 located in the middle of the width direction of the chassis 2 in a state where the chassis 2 is straight along the guide line X (θ = 0) is determined. Yes. If the cargo handling fork 6 in such a neutral position is turned by 90 ° so that the fork tip 5 faces sideward, the fork tip 5 is directed straight to the cargo handling position. However, as described in the prior art, since the chassis 2 is inclined with respect to the guide line X (θ ≠ 0), the loading fork at the neutral position according to the direction and magnitude of the inclination angle θ. The position of the fork tip 5 of 6 also moves. The moved position is calculated as the origin position by the information processing means 12.
[0022]
The above origin position coincides with the middle point f in FIG. 1 and is recorded as a coordinate value in the memory unit of the information processing means 12 immediately before the cargo handling operation is performed. However, when the cargo handling operation is not performed, the cargo handling fork 6 does not necessarily have to stand by at the neutral position, and it is sufficient if the information processing means 12 can recognize the initial position of the cargo handling fork 6 as a reference for starting control. Therefore, the elevating carriage 4 may be shifted in advance to one side in the vehicle width direction, or the cargo handling fork 6 may be swung in advance. In the following, for convenience of explanation, it is assumed that control is executed based on the neutral position.
[0023]
The information processing means 12 calculates values of the turning angle of the loading fork 6 and the shift distance of the lifting carriage 4 that are necessary to actually move the loading fork 6 from the origin position calculated as described above to the loading position. . Further, the information processing means 12 appropriately operates the control means 13 and 14 in accordance with the calculated value to control the rotation operation and the shift operation of the cargo handling fork 6 respectively. As a result, as shown in FIG. 2, since the cargo handling fork 6 can be directed straight with respect to the load N, even if the chassis 2 is inclined with respect to the guide line X, as shown in FIG. Can be in a straight posture with respect to the fixed station S.
[0024]
Accordingly, when the fixed station S is of a widespread type in which a pair of correction guides 17 for guiding the luggage N inward are arranged on both sides of the conveyor 16 as illustrated in FIG. In addition, as the baggage N is represented by an imaginary line, the bag N is not inclined so as to straddle the pair of correction guides 17. It slides down reliably from between the pair of straightening guides 17 to the upper surface of the conveyor 16.
[0025]
Further, when the load N is slightly deviated in the traveling direction of the chassis 2, the load handling assisting device 10 cannot completely correct such a position shift. However, as described above, a pair of correction guides are provided on both sides of the fixed station S. If each 17 is arranged, there will be no inconvenience such as the load N dropping out of the fixed station S or the load collapse.
[0026]
It should be noted that the present invention can be implemented in a mode in which various improvements, modifications, and variations are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention.
[0027]
【The invention's effect】
According to the loading assist device for a forklift according to the present invention, since the information processing means can recognize the position (origin) of the tip of the fork on the basis of the inclination angle at which the chassis tilts with respect to the guide line, For example, when placing on a fixed station or when picking up luggage from the fixed station, the chassis tilts with respect to the guide line, and further, the chassis approaches the fixed station due to the tilt of the chassis. The origin position of the cargo handling fork can be calculated each time even if it is too far or too far away. The value of the turning angle of the loading fork and the shift distance of the lifting carriage required to move the loading fork from the position of the fork tip recognized by the information processing means to the loading position where the loading fork actually loads Is calculated by the information processing means.
[0028]
Since the cargo handling assist device can control the rotation operation and the shift operation of the cargo handling fork according to the calculated value, the cargo handling fork can be directed straight to the load regardless of the posture of the chassis. Therefore, in the conventional technology, a technical problem such as a combination of a rotation operation in which the loading fork simply turns 90 ° and an operation in which the loading fork is moved forward by a predetermined distance, in other words, the chassis is guided. There is no inconvenience that the handling fork is also inclined with respect to the load as it is inclined with respect to the line.
[0029]
Furthermore, according to the material handling assist device according to the present invention, the chassis direction detection means is the two magnetic guide sensors arranged at the front and rear of the chassis, so that the relative vehicle in which each magnetic guide sensor detects the guide wire. The tilt angle at which the vehicle body tilts with respect to the guide line based on the position in the width direction, whether the position is different in the left or right direction in the vehicle width direction with respect to the guide line, and the distance between the two magnetic guide sensors Can be calculated. In addition, if the existing forklift is provided with two magnetic guide sensors, the existing forklift can be used as long as the detection signal sent from the magnetic guide sensor is directly input to the information processing means of the cargo handling assistance device. The cargo handling assisting device can be easily mounted with almost no additional work.
[0030]
Furthermore, according to the cargo handling assist device of the present invention, the rotation angle detection means and the shift amount detection means are encoders that encode the turning angle of the cargo handling fork and the shift distance of the lifting carriage, respectively. There is an advantage that it can be easily attached to an existing forklift with little modification.
[Brief description of the drawings]
FIG. 1 is a plan view showing a traveling process of a forklift equipped with a cargo handling assist device according to an embodiment of the present invention.
FIG. 2 is a plan view showing a loading / unloading process of a forklift equipped with a loading / unloading assisting device according to an embodiment of the present invention.
FIG. 3 is a block diagram showing a configuration of a cargo handling assistance apparatus according to an embodiment of the present invention.
FIG. 4 is an overall perspective view of a forklift equipped with a cargo handling assist device according to an embodiment of the present invention.
FIGS. 5A and 5B are a plan view and a sectional view showing a fixed station and a loaded state of a load according to the embodiment of the invention.
FIG. 6 is a plan view showing a traveling process of a conventional forklift.
[Explanation of symbols]
1: Forklift 2: Chassis 3: Mast 4: Lifting carriage 5: Fork tip 6: Handling fork 7, 8: Chassis direction detecting means 9: Rotating angle detecting means 10: Loading support device 11: Shift amount detecting means 12: Information processing Means 13, 14: Control means X: Guide line θ: Inclination angle

Claims (1)

A mast is set up on a chassis that is guided by a guide line and autonomously travels, and an elevating carriage that is supported by the mast so as to be movable up and down rotates the loading fork with respect to the chassis, and the loading fork is moved to the vehicle width. A forklift load assisting device that allows the fork tip of the load handling fork to reach a load handling position defined on a side of the chassis by shifting in a direction,
A chassis direction detecting means for detecting an inclination angle at which the chassis is inclined with respect to the guide line;
A rotation angle detecting means for detecting a turning angle at which the handling fork is turned with respect to the chassis;
Shift amount detecting means for detecting a shift distance of the elevating carriage in the vehicle width direction;
In order to cancel the tilt angle of the chassis detected by the chassis direction detecting means, the origin position of the fork tip of the loading fork is calculated based on the tilt angle of the chassis, and the fork tip of the loading fork is moved from the origin position to the cargo handling position. An information processing means for calculating a turning angle of the cargo handling fork and a shift distance of the elevating carriage necessary for moving to a position ;
Control means for controlling a rotation operation and a shift operation of the cargo handling fork according to the turning angle calculated by the information processing means and the shift distance;
A forklift load assisting device characterized by comprising:

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