forklift

Abstract

To provide a forklift with a simple structure capable of adjusting positions of a pair of forks in a longitudinal direction when the pair of forks extends rightward or leftward.SOLUTION: A forklift F comprises: a travel device 1 capable of advancing straight in a longitudinal direction; a pair of forks 2A, 2B extending in a first horizontal direction H1 and provided at an interval in a second horizontal direction H2; an area sensor 6 capable of detecting an object positioned in preset areas; and a sensor controller 7A configured to control the area sensor 6 to cause the area sensor 6 to scan limited areas AB to AE located in a direction in which the forks 2A and 2B extend, which are defined as the preset areas; and a travel controller 7B configured to control the travel device 1, when the second horizontal direction H2 is the longitudinal direction, to cause the travel device 1 to advance straight in the longitudinal direction on the basis of a detection result of the area sensor 6, so as to adjust positions of the forks 2A, 2B in the second horizontal direction H2.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a forklift truck in which the positions of a pair of forks are adjustable. [Background technology]

[0002] Patent Document 1 describes a forklift truck equipped with a traveling device that travels on a road surface, a pair of forks extending horizontally, and a rotation device (electric motor) that rotates the pair of forks around a rotation axis extending vertically. A forklift truck equipped with such a configuration can extend the forks to the right or left of the traveling device, so that a load supported by the forks can be placed on the right or left of the traveling device, and a load located on the right or left of the traveling device can be picked up with the forks.

[0003] However, when placing or picking up a load, the traveling device stops at a predetermined position, but the forks may deviate from the desired position. Specifically, for example, when the forks ascend along a mast extending in the vertical direction, the mast may tilt due to the load acting on the forks, causing the pair of forks extending to the right or left to deviate in the front-to-rear direction from the desired position. For this reason, there has been a demand for a device that allows the position of the forks to be adjusted in the front-to-rear direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-112212 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide a forklift truck that can adjust the position of a pair of forks in the front-to-rear direction with a simple configuration when the pair of forks are extending to the right or left. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the forklift of the present invention is characterized by comprising: a traveling device that can move straight in a forward and backward direction and travels on a road surface; a pair of forks that extend in a first horizontal direction and are spaced apart in a second horizontal direction perpendicular to the first horizontal direction; an area sensor that can detect objects located in a predetermined area by scanning the area; a sensor control unit that controls the area sensor to scan a limited area on the tip side of the forks that is located in the direction in which the pair of forks extend as the area; and a traveling control unit that controls the traveling device and, when the second horizontal direction is the forward and backward direction, adjusts the position of the pair of forks in the second horizontal direction by moving the traveling device straight in the forward and backward direction based on the detection result by the area sensor.

[0007] Preferably, the sensor control unit causes the area sensor to scan a pair of fork tip side areas spaced apart in the second horizontal direction as the areas.

[0008] Furthermore, when placing a load supported by the pair of forks, it is preferable that the sensor control unit causes the area sensor to scan the fork tip area located outside the pair of forks in the second horizontal direction as the area.

[0009] Furthermore, it is preferable that when the pair of forks pick up a load, the sensor control unit causes the area sensor to scan the fork tip area located inside the pair of forks in the second horizontal direction as the area.

[0010] Furthermore, it is preferable that the sensor control unit causes the area sensor to scan multiple areas with different ranges in a predetermined order, and the driving control unit calculates the driving distance for moving the driving device straight forward and backward based on an ordinal number indicating the area in which the object is detected.

[0011] It is also preferable that the device further includes a rotation device that rotates the pair of forks around a rotation axis extending vertically, and that the area sensor is configured to rotate together with the pair of forks around the rotation axis. [Effects of the Invention]

[0012] According to the present invention, it is possible to provide a forklift truck that can adjust the positions of a pair of forks in the front-to-rear direction with a simple configuration when the pair of forks are extending to the right or left. [Brief explanation of the drawings]

[0013] [Figure 1] 1A is a side view of a forklift according to an embodiment of the present invention, and FIG. 1B is a plan view of the forklift. [Figure 2] FIG. 2A is a block diagram showing a schematic configuration of a forklift according to the embodiment, and FIG. 2B is a plan view of forks and an area sensor provided in the forklift. [Figure 3] 1A to 1C are plan views of a forklift. [Figure 4] 10(A) and 10(B) are schematic diagrams showing the ranges of a plurality of preset areas. [Figure 5] 10(A) and 10(B) are schematic diagrams showing the ranges of a plurality of preset areas. [Figure 6] 10 is a flowchart of a fork position adjustment process when a load is placed. [Figure 7] 10 is a flowchart of a fork position adjustment process when picking up a load. [Figure 8]10A and 10B are plan views of the fork and the area sensor, showing a state in which the area sensor detects at least one of the support posts of the rack and a load placed on the rack. [Figure 9] 10(A) and 10(B) are plan views of the fork and the area sensor, showing a state in which the partition wall of the pallet is detected by the area sensor. DETAILED DESCRIPTION OF THE INVENTION

[0014] An embodiment of the present invention will be described with reference to the drawings. Note that the front-rear direction X, the left-right direction Y, and the vertical direction Z, indicated by arrows in the drawings, are linear directions that are perpendicular to each other. Also, a first horizontal direction H1 (hereinafter referred to as the "H1 direction") and a second horizontal direction H2 (hereinafter referred to as the "H2 direction") indicated by arrows in the drawings are linear directions that are perpendicular to each other and parallel to a horizontal plane.

[0015] 1(A) and 1(B), the forklift F according to this embodiment is an unmanned three-way stacking truck, and is equipped with a traveling device 1, a pair of forks 2A and 2B, a lifting device 3, a shifting device 4, a rotating device 5, an area sensor 6, and a control device 7. The forklift F performs a load placing operation in which a load M supported by the forks 2A and 2B is placed in a predetermined location, and a load retrieval operation in which the forks 2A and 2B retrieve the load M from the predetermined location.

[0016] The traveling device 1 is configured to be able to travel straight in the forward / backward direction X, estimates its own vehicle position, and autonomously travels on a road surface along a predetermined traveling route to a predetermined target point. That is, the traveling device 1 includes a position estimation device that estimates the own vehicle position, a steering device that steers based on the own vehicle position and the traveling route, and a braking device that brakes to stop traveling.

[0017] The forks 2A, 2B (hereinafter referred to as "forks 2") are claws that extend in the H1 direction and are spaced apart in the H2 direction. The forks 2 are configured to support a load M by being inserted into the load M. Hereinafter, in the H1 direction in which the forks 2 extend, the fork base end direction D1 approaching the rotation axis R described below will be referred to as the "D1 direction," and the fork tip direction D2 moving away from the rotation axis R will be referred to as the "D2 direction." Furthermore, in the H2 direction in which the forks 2 are lined up, the fork right direction D3 facing to the right when viewed from the D1 direction toward the D2 direction will be referred to as the "D3 direction," and the fork left direction D4 facing to the left when viewed from the D1 direction toward the D2 direction will be referred to as the "D4 direction."

[0018] The lift device 3 moves the forks 2 in the vertical direction Z relative to the traveling device 1 (i.e., raises and lowers the forks 2). The lift device 3 also moves the shift device 4, the rotation device 5, and the area sensor 6 in the vertical direction Z together with the forks 2.

[0019] The shift device 4 moves the fork 2 in the left-right direction Y relative to the traveling device 1. That is, the shift device 4 can move the fork 2 in the left-right direction Y while the traveling device 1 is stopped from traveling. The shift device 4 also moves the rotation device 5 in the left-right direction Y together with the fork 2.

[0020] The rotation device 5 rotates the forks 2 around a rotation axis R extending in the vertical direction Z. When the rotation device 5 rotates the forks 2, the H1 direction in which the forks 2 extend and the H2 direction in which the forks 2 are aligned change.

[0021] The area sensor 6 is configured to be able to detect an object located in a predetermined area (hereinafter referred to as "set area A") by scanning the set area A with laser light. Specifically, the area sensor 6 projects infrared laser light in one horizontal direction, changes the direction of the laser light projection by a predetermined angle, and repeats the above-mentioned laser light projection to one-dimensionally scan the set area A in the horizontal direction. When an object is present in the direction of the laser light projection, the area sensor 6 receives the laser light reflected by the object, and calculates the direction and distance (i.e., the position of the reflection point) of the laser light based on the received laser light, using the area sensor 6 as a reference point. Then, when the reflection point of the laser light is included in the set area A, the area sensor 6 outputs a signal indicating that an object located in the set area A has been detected.

[0022] The area sensor 6 is provided so as not to protrude from the traveling device 1 in the left-right direction Y. In this embodiment, the area sensor 6 is provided on the center line CL of the fork 2 in the H2 direction. The area sensor 6 is also provided below the fork 2 so that the laser light is not blocked by the load M.

[0023] The control device 7 controls the traveling device 1 and the shift device 4 based on the detection result by the area sensor 6. As shown in FIG. 2(A), the control device 7 is made up of a sensor control unit 7A, a traveling control unit 7B, and a shift control unit 7C.

[0024] The sensor control unit 7A controls the area sensor 6 to scan areas AA to AE (see FIG. 2B for all of these) as the set area A. Specifically, the sensor control unit 7A controls the area sensor 6 to scan areas AA, AB, and AC when the forklift F is performing a loading operation, and controls the area sensor 6 to scan areas AA, AD, and AE when the forklift F is performing a loading operation. As shown in FIG. 2B, the area AA is configured to include an area located inside the fork 2 (i.e., in the D4 direction from fork 2A and in the D3 direction from fork 2B). The areas AB to AE are limited areas on the fork tip side located in the direction in which the fork 2 extends, and are configured to include an area located in the D2 direction from the fork 2. The areas AB and AC are areas scanned before the loading operation, and are a pair of areas located outside the fork 2 (i.e., in the D3 direction from fork 2A or in the D4 direction from fork 2B) and spaced apart in the H2 direction. Areas AD and AE are scanned before the loading operation, and are a pair of areas located inside the fork 2 and spaced apart in the H2 direction. The sensor control unit 7A changes the range of areas AB to AE by switching between multiple areas AB to AE, which will be described later.

[0025] When the H2 direction is the front-rear direction X (i.e., when the fork 2 faces right or left), the traveling control unit 7B adjusts the position of the fork 2 in the H2 direction by controlling the traveling device 1 based on the detection result by the area sensor 6. Specifically, the traveling control unit 7B calculates the traveling distance by which the traveling device 1 travels straight in the front-rear direction X as the position adjustment amount for moving the fork 2 in the H2 direction, and adjusts the position of the fork 2 in the H2 direction by causing the traveling device 1 to travel by that traveling distance.

[0026] When the H2 direction is the left-right direction Y (i.e., when the fork 2 faces forward), the shift control unit 7C adjusts the position of the fork 2 in the H2 direction by controlling the shift device 4 based on the detection result by the area sensor 6. Specifically, the shift control unit 7C determines the shift operation amount for operating the shift device 4 as the position adjustment amount for moving the fork 2 in the H2 direction, and operates the shift device 4 by that shift operation amount to adjust the position of the fork 2 in the H2 direction.

[0027] A method for adjusting the position of the fork 2 according to the orientation of the fork 2 will be described with reference to Figure 3. Figures 3(A) and (B) show the forklift F when the H2 direction is the front-rear direction X, and Figure 3(C) shows the forklift F when the H2 direction is the left-right direction Y.

[0028] 3A shows a state in which the fork 2 extends to the right. In this state, the traveling control unit 7B moves the fork 2 in the direction D3 by moving the traveling device 1 straight backward, and moves the fork 2 in the direction D4 by moving the traveling device 1 straight forward.

[0029] 3(B) shows a state in which the fork 2 extends leftward. In this state, the traveling control unit 7B moves the fork 2 in the direction D3 by moving the traveling device 1 straight forward, and moves the fork 2 in the direction D4 by moving the traveling device 1 straight backward.

[0030] 3(C) shows a state in which the fork 2 extends forward. In this state, the shift control unit 7C operates the shift device 4 to move the fork 2 in directions D3 and D4.

[0031] The plurality of pre-set areas AB to AE will be described with reference to Figures 4 and 5. Figure 4(A) shows the 1st to 31st areas AB1 to AB 314B shows a schematic diagram of a plurality of areas AC, 1st to 31st areas AC1 to AC 31 5A shows a schematic diagram of a plurality of areas AD, 1st to 31st areas AD1 to AD 31 5B shows a schematic diagram of a plurality of areas AE, 1st to 31st areas AE1 to AE 31 4 and 5 show a position that is a predetermined distance (for example, about 1350 mm) away from the area sensor 6 in the D2 direction. In addition, in FIGS. 4 and 5, the 4th to 30th areas AB4 to AB 30 ,AC4~AC 30 ,AD4~AD 30 ,AE4~AE 30 The symbols indicating the difference are omitted.

[0032] As shown in Figure 4(A), the first area AB1 extends from the area sensor 6 in the directions D2 and D3, and includes an area located in the D3 direction from the fork 2A in order to detect an object located in the D3 direction in a location facing the fork 2. The second to 31st areas AB2 to AB 31 is configured to be an area obtained by expanding the first area AB1 in the D3 direction by 10 mm on the reference line SL.

[0033] As shown in Figure 4(B), the first area AC1 extends from the area sensor 6 in the directions D2 and D4, and includes an area located in the D4 direction from the fork 2B in order to detect an object located in the D4 direction facing the fork 2. The second to thirty-first areas AC2 to AC 31 is configured to be an area obtained by expanding the first area AC1 in the D4 direction by 10 mm on the reference line SL.

[0034] As shown in FIG. 5A, the first area AD1 extends from the area sensor 6 in the directions D2 and D3, and is located inside the fork 2 in the direction H2 to detect an object located in a position facing the fork 2. The second to 31st areas AD2 to AD31 is configured to be an area obtained by expanding the first area AD1 in the D4 direction by 10 mm on the reference line SL.

[0035] As shown in FIG. 5B, the first area AE1 extends from the area sensor 6 in the directions D2 and D4, and is located inside the fork 2 in the direction H2 to detect an object located in a position facing the fork 2. The second to thirty-first areas AE2 to AE 31 is configured to be an area obtained by expanding the first area AE1 in the D3 direction by 10 mm on the reference line SL.

[0036] The flow of the fork position adjustment process performed by the forklift F when placing a load will be described with reference to FIG. The fork position adjustment process shown in FIG. 6 is started when the fork 2B is supporting the load M and the place where the load M should be placed is separated from the area sensor 6 by a predetermined distance in the H1 direction.

[0037] 6, the sensor control unit 7A causes the area sensor 6 to scan the area AA (step S1) and determines whether an object is detected in the area AA (step S2). If an object is detected in the area AA (step S2: YES), the forklift F determines that an obstacle that prevents the load M from being placed is present, and ends the fork position adjustment process without operating the traveling device 1 and the shift device 4, and stops the load placement operation.

[0038] On the other hand, if no object is detected in area AA (step S2: NO), the sensor control unit 7A causes the area sensor 6 to scan area AB (step S3) and also causes the area sensor 6 to scan area AC (step S4). That is, the areas AB and AC are scanned simultaneously.

[0039] In step S3, the sensor control unit 7A controls the area sensor 6 to scan a plurality of areas AB with different ranges in a predetermined order to detect an object located in the direction D3 opposite the fork 2, thereby expanding the range of the area AB in the direction D3. Specifically, the sensor control unit 7A controls the area sensor 6 to scan the areas AB in order from the first area AB1, and also controls the area sensor 6 to scan the areas AB in the "N"th area AB. N If an object is detected in area AB after "N+1" N+1 ~AB 31 In other words, when an object is detected in one area AB, the scanning in step S3 is terminated in order to reduce the time.

[0040] In step S4, the sensor control unit 7A controls the area sensor 6 to scan a plurality of areas AC having different ranges in a predetermined order to detect an object located in the direction D4 opposite the fork 2, thereby expanding the range of the area AC in the direction D4. Specifically, the sensor control unit 7A controls the area sensor 6 to scan the areas AC in order from the first area AC1, and also controls the area sensor 6 to scan the areas AC in the "N"th area AC. N If an object is detected in area AC after "N+1", N+1 ~AC 31 In other words, when an object is detected in one area AC, the scanning in step S4 is terminated in order to reduce the time.

[0041] Next, the cruise control unit 7B or the shift control unit 7C determines whether an object has been detected in either area AB or AC in steps S3 or S4 (step S5). Furthermore, if an object has been detected in either area AB or AC (step S5: YES), the cruise control unit 7B or the shift control unit 7C determines whether an object has been detected in the first area AB1 or AC1 (step S6).

[0042] If no object is detected in either area AB or AC (step S5: NO), the forklift F performs a load placement operation by placing the load M in a location opposite the fork 2 without adjusting the position of the fork 2 in the H2 direction.

[0043] Also, if an object is detected in the first area AB1, AC1 (step S6: YES), the travel control unit 7B or the shift control unit 7C operates the travel device 1 or the shift device 4 so that the fork 2 moves by a predetermined amount in order to increase the distance in the H2 direction between the detected object and the fork 2 and area sensor 6 (step S7).

[0044] Specifically, if an object is detected in the first area AB1 while the forks 2 are facing right, the traveling control unit 7B operates the traveling device 1 so that the forks 2 move a certain amount in the direction D4 (i.e., forward). Also, if an object is detected in the first area AC1 while the forks 2 are facing right, the traveling control unit 7B operates the traveling device 1 so that the forks 2 move a certain amount in the direction D3 (i.e., backward).

[0045] Furthermore, if an object is detected in the first area AB1 while the forks 2 are facing left, the traveling control unit 7B operates the traveling device 1 so that the forks 2 move a certain amount in the direction D4 (i.e., backward). Furthermore, if an object is detected in the first area AC1 while the forks 2 are facing left, the traveling control unit 7B operates the traveling device 1 so that the forks 2 move a certain amount in the direction D3 (i.e., forward).

[0046] Furthermore, if an object is detected in the first area AB1 while the forks 2 are facing forward, the shift control unit 7C operates the shift device 4 to move the forks 2 a certain amount in the direction D4 (i.e., leftward). If an object is detected in the first area AC1 while the forks 2 are facing forward, the shift control unit 7C operates the shift device 4 to move the forks 2 a certain amount in the direction D3 (i.e., rightward).

[0047] As described above, after the forks 2 are moved by a certain amount in the H2 direction by the travel control unit 7B or the shift control unit 7C in step S7, the forklift F repeats step S3 and subsequent steps.

[0048] If an object is detected in either area AB or AC (step S5: YES), and if an object is not detected in the first area AB1 or AC1 (step S6: NO), the travel control unit 7B or the shift control unit 7C calculates the position adjustment amount of the fork 2 (step S8).

[0049] Specifically, when an object is detected in both areas AB and AC, the driving control unit 7B or the shift control unit 7C calculates "D" (unit: mm), which is a position adjustment amount with the D3 direction being the positive direction, based on the ordinal numbers indicating the areas AB and AC where the object was detected, according to the following (Equation 1). Note that "A" in (Equation 1) is the ordinal number of the area AB where the object was detected, and "B" in (Equation 1) is the ordinal number of the area AC where the object was detected. For example, if no object is detected in the first to fourth areas AB1 to AB4, but an object is detected in the fifth area AB5, "A" is "5."

number

[0050] Furthermore, when an object is detected only in area AB, the driving control unit 7B or the shift control unit 7C calculates "D" (unit: mm), which is a position adjustment amount with the D3 direction as the positive direction, based on the ordinal number indicating area AB where the object is detected, according to the following (Equation 2). Note that "A" in (Equation 2) is the ordinal number of area AB where the object is detected, and "X" in (Equation 2) A " is the ordinal number of the target area. For example, if the target is to detect an object in the fifth area AB5, "X A " is "5".

number

[0051] Furthermore, when an object is detected only in area AC, the driving control unit 7B or the shift control unit 7C calculates "D" (unit: mm), which is a position adjustment amount with the D3 direction as the positive direction, based on the ordinal number indicating area AC where the object is detected, according to the following (Equation 3). Note that "B" in (Equation 3) is the ordinal number of area AC where the object is detected, and "X" in (Equation 3) B " is the ordinal number of the target area. For example, if the target is to detect an object in the fifth area AC5, "X B " is "5".

number

[0052] Then, the traveling control unit 7B or the shift control unit 7C operates the traveling device 1 or the shift device 4 so that the fork 2 moves by the position adjustment amount "D" calculated in step S8 (step S9).

[0053] Specifically, when the position adjustment amount "D" is calculated as a positive number while the fork 2 is facing right, the traveling control unit 7B operates the traveling device 1 so that the fork 2 moves in the D3 direction (i.e., backward). On the other hand, when the position adjustment amount "D" is calculated as a negative number while the fork 2 is facing right, the traveling control unit 7B operates the traveling device 1 so that the fork 2 moves in the D4 direction (i.e., forward).

[0054] Furthermore, when the position adjustment amount "D" is calculated as a positive number while the fork 2 is facing left, the traveling control unit 7B operates the traveling device 1 so that the fork 2 moves in the D3 direction (i.e., forward). When the position adjustment amount "D" is calculated as a negative number while the fork 2 is facing left, the traveling control unit 7B operates the traveling device 1 so that the fork 2 moves in the D4 direction (i.e., backward).

[0055] Furthermore, when the position adjustment amount "D" is calculated as a positive number while the fork 2 is facing forward, the shift control unit 7C operates the shift device 4 to move the fork 2 in the D3 direction (i.e., rightward). When the position adjustment amount "D" is calculated as a negative number while the fork 2 is facing forward, the shift control unit 7C operates the shift device 4 to move the fork 2 in the D4 direction (i.e., leftward).

[0056] As described above, after the position of the fork 2 in the H2 direction is adjusted by the travel control unit 7B or the shift control unit 7C in step S9, the forklift F sets the location opposite the fork 2 as a load placement location and places the load M there.

[0057] Next, the flow of the fork position adjustment process performed by the forklift F when picking up a load will be described with reference to FIG. The fork position adjustment process shown in FIG. 7 is started when the load M to be picked up by the forks 2 and the area sensor 6 are spaced apart by a predetermined distance in the H1 direction.

[0058] 7, the sensor control unit 7A causes the area sensor 6 to scan the area AA (step S11) and determines whether an object is detected in the area AA (step S12). If an object is detected in the area AA (step S12: YES), the forklift F determines that an obstacle is present that prevents the forklift F from picking up the load M, and ends the fork position adjustment process without operating the traveling device 1 and the shift device 4, and stops the load picking operation.

[0059] On the other hand, if no object is detected in area AA (step S12: NO), the sensor control unit 7A causes the area sensor 6 to scan area AD (step S13) and also causes the area sensor 6 to scan area AE (step S14). That is, the areas AD and AE are scanned simultaneously.

[0060] In step S13, the sensor control unit 7A controls the area sensor 6 to scan a plurality of areas AD with different ranges in a predetermined order to detect an object located in a position opposite the fork 2, thereby expanding the range of the area AD in the direction D4. Specifically, the sensor control unit 7A controls the area sensor 6 to scan the areas AD in order from the first area AD1, and also controls the area sensor 6 to scan the areas AD in the "N"th area AD. N If an object is detected in Area AD after "N+1" N+1 ~AD 31 In other words, when an object is detected in one area AD, the scanning in step S13 is terminated in order to reduce the time.

[0061] In step S14, the sensor control unit 7A controls the area sensor 6 to scan a plurality of areas AE having different ranges in a predetermined order to detect an object located in a position opposite the fork 2, thereby expanding the range of the area AE in the direction D3. Specifically, the sensor control unit 7A controls the area sensor 6 to scan the areas AE in order from the first area AE1, and also controls the area sensor 6 to scan the areas AE in the "N"th area AE. N If an object is detected in area (N+1) or later, N+1 ~AE 31 In other words, when an object is detected in one area AE, the scanning in step S14 is terminated in order to reduce the time.

[0062] Next, the traveling control unit 7B or the shift control unit 7C calculates the position adjustment amount of the fork 2 (step S15). Specifically, the traveling control unit 7B or the shift control unit 7C calculates "D" (unit: mm), which is the position adjustment amount with the D3 direction being the positive direction, based on the ordinal numbers indicating the areas AD and AE where the object was detected, according to the following (Equation 4). Note that "A" in (Equation 4) is the ordinal number of the area AD where the object was detected, and "B" in (Equation 4) is the ordinal number of the area AE where the object was detected. For example, if no object was detected in the first to fourth areas AD1 to AD4, but an object was detected in the fifth area AD5, "A" is "5."

number

[0063] Then, the traveling control unit 7B or the shift control unit 7C operates the traveling device 1 or the shift device 4 in the same manner as in step S9 described above so that the fork 2 moves by the position adjustment amount "D" calculated in step S15 (step S16).

[0064] Furthermore, the travel control unit 7B or the shift control unit 7C determines whether or not an object is detected in the first area AD1, AE1 in steps S13, S14 (step S17). If an object is not detected in the first area AD1, AE1 (step S17: NO), the forklift F ends the fork position adjustment process and performs a load pick-up operation to pick up the load M from a location opposite the forks 2.

[0065] On the other hand, if an object is detected in the first area AD1, AE1 (step S17: YES), the forklift F repeats step S13 and subsequent steps. In this way, by repeating step S13 and subsequent steps, the edge of the object is reliably detected. That is, for example, if an object is detected in the first area AD1 in step S13, the edge of the object may be located in the direction D3 from area AD1. In this case, when the fork 2 and area sensor 6 move in the direction D3 in step S16, the scan in step S13 is performed again, and it is found that no object is detected in the first area AD1, but the edge of the object is located in the second and subsequent areas AD2 to AD 31 Since the object is detected in either direction, the edge of the object in the D3 direction is reliably detected.

[0066] Next, a specific example of the operation of the forklift F when placing a load will be described with reference to Figure 8. Figures 8(A) and (B) show the state at the start of the fork position adjustment process, with the traveling device 1 stopping its travel at a position where the rack support 11 and the area sensor 6 are separated by a predetermined distance in the H1 direction. The rack is a platform for storing loads M, and has a shelf (not shown) that supports the loads M, and a support 11 that is a vertical member extending in the vertical direction Z that supports the shelf.

[0067] 8A shows a state in which an object is detected in only one of the areas AB and AC. Specifically, FIG. 8A shows a state in which no object is detected in the first and second areas AB1 and AB2, and a support pole 11 is detected in the third area AB3, and the first to 31st areas AC1 to AC 31In this case, the position adjustment amount of the fork 2 is calculated according to (Equation 2). A If "D4" is preset to "5" (i.e., the fifth area AB5 is the target area), "D=-20" is calculated as the position adjustment amount. Therefore, the traveling device 1 or the shift device 4 moves the fork 2 by 20 mm in the D4 direction. In this way, the fork 2 moves so that the support 11 is positioned in the target area, and it becomes possible to place the load M at a predetermined distance from the support 11.

[0068] FIG. 8B shows a state in which an object is detected in both areas AB and AC. Specifically, FIG. 8B shows a state in which an object is detected in the first to eleventh areas AB1 to AB 11 No object is detected in the 12th area AB 12 In this state, load N placed on the rack is detected, and no object is detected in the 1st to 9th areas AC1 to AC9, and no object is detected in the 10th area AC 10 shows a state in which the support 11 is detected. In this case, "D=10" is calculated as the position adjustment amount of the fork 2 according to (Equation 1). Therefore, the traveling device 1 or the shift device 4 moves the fork 2 by 10 mm in the D3 direction. In this way, the fork 2 moves so that the center line CL is positioned at the midpoint between the support 11 and the load N, and it becomes possible to place the load M at an equal distance from the support 11 and the load N.

[0069] Next, a specific example of the operation of the forklift F when picking up an item will be described with reference to Figure 9. Figures 9(A) and (B) show the state at the start of the fork position adjustment process, with the traveling device 1 stopped in a position in the H1 direction where the item M is separated by a predetermined distance from the area sensor 6. The item M is a pallet carrying an object to be transported, and has a pair of insertion openings 21A, 21B into which the forks 2 are inserted, and a partition wall 22 separating the insertion openings 21A, 21B.

[0070] 9A and 9B show a state in which the partition wall 22 is detected in the areas AD and AE. Specifically, FIG. 9A shows a state in which no object is detected in the first to fourth areas AD1 to AD4, one edge of the partition wall 22 is detected in the fifth area AD5, and the first to fourteenth areas AE1 to AE 14 No object was detected in the 15th area AE 15 indicates a state in which the other edge of the partition wall portion 22 is detected. In this case, "D=50" is calculated as the position adjustment amount of the fork 2 according to (Equation 4).

[0071] FIG. 9B shows the first to eleventh areas AD1 to AD 11 No object is detected in the 12th area AD 12 In the state where one edge of the partition wall portion 22 is detected, and the first to twenty-first areas AE1 to AE 21 No object was detected in the 22nd area AE 22 indicates a state in which the other edge of the partition wall portion 22 is detected. In this case, too, "D=50" is calculated as the position adjustment amount of the fork 2 according to (Equation 4).

[0072] 9(A) and 9(B), the traveling device 1 or the shift device 4 moves the forks 2 by 50 mm in the D3 direction. In this way, even when picking up loads M with partitions 22 of different widths in the H2 direction, the forks 2 move so that the center line CL is positioned at the center of the partitions 22, making it possible to properly insert the forks 2 into the insertion openings 21A and 21B.

[0073] In this embodiment, the following effects are obtained. (1) The sensor control unit 7A causes the area sensor 6 to scan a limited area AB-AE (the area toward the tip of the fork) located in the direction D2 along which the fork 2 extends. When the direction H2 (second horizontal direction) is the fore-and-aft direction X, the travel control unit 7B adjusts the position of the fork 2 in the H2 direction by moving the travel device 1 straight in the fore-and-aft direction X based on the detection results of the area sensor 6. This configuration detects an object located in the limited area AB-AE, which simplifies the process for detecting an object compared to a configuration that detects an object by scanning the entire perimeter. By detecting an adjacent object (the rack support 11 and load N) facing the fork 2, the position of the fork 2 can be adjusted so that the load M is placed in an appropriate position away from the support 11 and load N. Furthermore, by detecting an object (load M) facing the fork 2, the position of the fork 2 can be adjusted so that the center of the load M is located on the center line CL of the fork 2. Therefore, when the fork 2 extends to the right or left (that is, when the H2 direction is the front-rear direction X), the position of the fork 2 in the front-rear direction X can be adjusted with a simple configuration.

[0074] (2) The sensor control unit 7A causes the area sensor 6 to scan a pair of fork tip areas (i.e., areas AB and AC or areas AD and AE) spaced apart in the H2 direction. This configuration further simplifies the process for detecting an object compared to a configuration in which the entire area located in the D2 direction in which the forks 2 extend is scanned.

[0075] (3) When placing the load M supported by the forks 2, the sensor control unit 7A causes the area sensor 6 to scan the fork tip side area (i.e., areas AB and AC) located outside the forks 2 in the H2 direction. With this configuration, it is possible to detect an object adjacent to the location facing the forks 2.

[0076] (4) When the forks 2 pick up the load M, the sensor control unit 7A causes the area sensor 6 to scan the fork tip side area (i.e., areas AD and AE) located inside the forks 2 in the H2 direction. With this configuration, it is possible to detect an object located in a position facing the forks 2.

[0077] (5) The traveling control unit 7B calculates the distance traveled by the traveling device 1 in the forward / backward direction X based on the ordinal number indicating the area where the object was detected. This configuration makes it possible to determine the distance traveled by the traveling device 1 in the forward / backward direction X without calculating the distance from the area sensor 6 to the object in the H2 direction.

[0078] (6) The area sensor 6 is configured to rotate together with the fork 2 around the rotation axis R. With this configuration, the area scanned by the area sensor 6 can be automatically changed by the rotation device 5 rotating the fork 2.

[0079] The present invention is not limited to the above-described embodiment, and the above configurations can be modified. For example, the following modifications can be made, or the following modifications can be combined to make the present invention.

[0080] The arrangement of the area sensors 6 may be changed as appropriate as long as the laser light emitted and received by the area sensors 6 is not blocked by the load M. The number of area sensors 6 may also be changed as appropriate. For example, the area sensor for detecting an object adjacent to the location opposite the forks 2 and the area sensor for detecting an object located at the location opposite the forks 2 may each be different sensors.

[0081] The present invention may be applied to forklifts other than three-way stacking trucks, for example, lateral stacking trucks or side forklifts. [Explanation of symbols]

[0082] 1 Running gear 2A, 2B fork 3 Lifting device 4 Shift device 5 Rotating device 6 Area Sensor 7 Control Device 7A Sensor control unit 7B Travel control unit 7C Shift control unit F Forklift M,N load R rack X Anteroposterior direction Y left / right direction Z vertical direction D1 Fork base end direction D2 Fork tip direction D3 Fork right D4 Fork left H1 1st horizontal direction H2 2nd horizontal direction AA Area AB,AB1~AB 31 Area (fork tip area) AC, AC1~AC 31 Area (fork tip area) AD, AD1~AD 31 Area (fork tip area) AE, AE1~AE 31 Area (fork tip area) CL center line SL Reference Line

Claims

1. A traveling device that can move straight forward and backward and travels on a road surface; a pair of forks extending in a first horizontal direction and spaced apart in a second horizontal direction perpendicular to the first horizontal direction; an area sensor capable of scanning a predetermined area to detect an object located in the area; a sensor control unit that controls the area sensor to scan a limited fork tip side area located in the direction in which the pair of forks extend, as the area; a travel control unit that controls the traveling device and, when the second horizontal direction is the front-rear direction, adjusts the position of the pair of forks in the second horizontal direction by moving the traveling device straight in the front-rear direction based on the detection result by the area sensor, the area sensor is disposed so as to move vertically together with the pair of forks and to be positioned below the pair of forks, When placing a load supported by the pair of forks, the sensor control unit causes the area sensor to scan a fork vicinity area that is limited to an area closer to the area sensor than the fork tip side area and includes an area located inside the pair of forks when viewed from above, and when no object is detected in the fork vicinity area, causes the area sensor to scan the fork tip side area that is located outside the pair of forks in the second horizontal direction. A forklift characterized by:

2. A traveling device that can move straight forward and backward and travels on a road surface; a pair of forks extending in a first horizontal direction and spaced apart in a second horizontal direction perpendicular to the first horizontal direction; an area sensor capable of scanning a predetermined area to detect an object located in the area; a sensor control unit that controls the area sensor to scan a limited fork tip side area located in the direction in which the pair of forks extend, as the area; a travel control unit that controls the traveling device and, when the second horizontal direction is the front-rear direction, adjusts the position of the pair of forks in the second horizontal direction by moving the traveling device straight in the front-rear direction based on the detection result by the area sensor, the area sensor is disposed so as to move vertically together with the pair of forks and to be positioned below the pair of forks, When the pair of forks pick up a load, the sensor control unit causes the area sensor to scan a fork vicinity area, which is limited to an area closer to the area sensor than the fork tip side area and includes an area located inside the pair of forks when viewed from above, and when no object is detected in the fork vicinity area, causes the area sensor to scan the fork tip side area located inside the pair of forks in the second horizontal direction. A forklift characterized by:

3. The sensor control unit causes the area sensor to scan a pair of the fork tip side areas spaced apart in the second horizontal direction as the areas.

3. The forklift according to claim 1 or 2.

4. the sensor control unit causes the area sensor to scan the plurality of areas having different ranges in a predetermined order; The travel control unit calculates a travel distance for causing the traveling device to travel straight in the forward / backward direction based on an ordinal number indicating the area in which the object is detected.

3. The forklift according to claim 1 or 2.

5. The apparatus further includes a rotation device that rotates the pair of forks around a rotation axis that extends in a vertical direction, The area sensor is configured to rotate around the rotation axis together with the pair of forks.

3. The forklift according to claim 1 or 2.

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