JP6631461B2 - forklift - Google Patents

Description

  The present invention relates to a forklift.

  Patent Literature 1 discloses a forklift for transporting a loaded pallet. The forklift described in Patent Literature 1 detects the position of a flat pallet from a captured image. Then, the position of the fork is corrected based on the detected position of the flat pallet.

JP 2010-189130 A

  By the way, a forklift sometimes stacks post pallets. The post pallet includes a mounting table on which a load is placed and a plurality of columns. When stacking the post pallets, the posts of the post pallets supported by the forks are stacked on the posts of the post pallets already placed. At this time, if the placed post pallet is tilted, the columns cannot be stacked, and the post pallets may not be stacked.

  An object of the present invention is to provide a forklift capable of stacking post pallets.

  A forklift for solving the above-mentioned problem is a forklift for stacking a post pallet including a mounting table on which a load is mounted and a plurality of columns, and a forklift stacked on the first post pallet placed. A fork supporting the second post pallet, a two-dimensional range finder provided at the tip of the fork, and measuring a distance from the first post pallet at each of a plurality of irradiation angles; When stacking the second post pallet, the first post pallet with respect to the vehicle width direction of the forklift based on the distance from at least two of the plurality of columns to the two-dimensional distance meter and the irradiation angle. And a control unit for calculating the inclination and the center position.

  According to this, the inclination of the first post pallet with respect to the vehicle width direction of the forklift and the center position can be calculated from the distance to the at least two columns and the irradiation angles measured by the two-dimensional rangefinder. The body of the forklift is tilted according to the inclination of the first post pallet, and the second post pallet can be stacked in a state where the center position and the center of the body of the forklift are aligned. Thereby, the inclination of the first post pallet with respect to the vehicle width direction is corrected, and the column of the second post pallet can be stacked on the column of the first post pallet. Therefore, the post pallets can be stacked.

  Regarding the forklift, the first post pallet includes the four columns, and the control unit is located on the forklift side when stacking the second post pallet on the first post pallet. The inclination of the first post pallet with respect to the vehicle width direction of the forklift and the center position may be calculated from the distance between the two columns and the two-dimensional distance meter and the irradiation angle.

According to this, it is easy to calculate the inclination and the center position of the first post pallet.
The forklift is provided with at least two sensors for detecting whether the second post pallet is in contact with the fork, and the control unit is configured to lower the fork supporting the second post pallet. When all the sensors no longer detect that the second post pallet is in contact with the fork, all the columns of the second post pallet are stacked on the columns of the first post pallet. May be determined.

  When stacking the second post pallet on the first post pallet, the fork is lowered after the second post pallet supported by the fork is moved directly above the first post pallet. At this time, when all the columns of the second post pallet are stacked on all the columns of the first post pallet, the second post pallet moves away from the fork. Will not detect that it is in contact with If at least one strut of the second post pallet is not loaded, the lowering of the fork lowers the second post pallet. Thus, at least one sensor detects that the second post pallet is in contact with the fork. Thereby, the control unit can determine whether or not the second post pallet is stacked on the first post pallet based on the detection result of the sensor.

  In the forklift, when raising the fork, the control unit may detect the height of the column by determining whether or not a distance to the column can be measured by the two-dimensional distance meter.

  According to this, when the fork is raised, the height of the column of the first post pallet can be detected. The control unit can raise the fork supporting the second post pallet according to the height of the column in the first post pallet. Therefore, an excessive rise of the fork and an insufficient rise of the fork are suppressed.

  Regarding the forklift, the controller controls the distance from the two-dimensional distance meter to at least two of the plurality of columns when the rake for supporting the second post pallet on the fork, and the irradiation angle. The inclination and the center position of the first post pallet with respect to the vehicle width direction of the forklift may be calculated.

  According to this, it is suppressed that the second post pallet is scooped in an inclined state.

  According to the present invention, post pallets can be stacked.

The schematic side view of a forklift. (A) is a sectional view of a fork, and (b) is a plan view of the fork. (A)-(c) is schematic which shows the movement of the fork when stacking a post pallet. FIG. 9 is a diagram for explaining a method of calculating the inclination of the first post pallet. The figure which shows the effect | action of a forklift. (A) is a perspective view showing the relationship between the sensor and the second post pallet when some of the columns of the second post pallet are not stacked on the columns of the first post pallet; FIG. 4C is a plan view showing the relationship between the sensor and the second post pallet when some of the columns of the post pallet are not stacked on the columns of the first post pallet; (D) is a sectional view taken along line dd of (b).

Hereinafter, an embodiment of a forklift will be described.
As shown in FIG. 1, the forklift 10 includes a vehicle body 11 and a cargo handling device 12 provided on the vehicle body 11. The forklift 10 includes a pair of reach legs 13 extending in a direction away from the vehicle body 11. Each reach leg 13 is provided with a front wheel 14. A rear wheel 15 is provided on the vehicle body 11. In the present embodiment, the rear wheels 15 serve as steering wheels and driving wheels.

  The cargo handling device 12 includes a two-stage mast 17. The mast 17 includes an outer mast 18 and an inner mast 19. The cargo handling device 12 includes a lift cylinder 20 connected to the inner mast 19. The cargo handling device 12 includes a reach cylinder 22 connected to the mast 17. The lift cylinder 20 and the reach cylinder 22 are hydraulic cylinders. The inner mast 19 moves up and down by supplying and discharging hydraulic oil to and from the lift cylinder 20. The mast 17 moves along the reach leg 13 so as to approach and separate from the vehicle body 11 by supplying and discharging hydraulic oil to and from the reach cylinder 22.

  The forklift 10 includes a pair of forks 23 and a lift bracket 24 for fixing the forks 23 to the mast 17. The fork 23 and the lift bracket 24 move up and down as the inner mast 19 moves up and down.

  The forklift 10 includes a hydraulic pump 25 that supplies hydraulic oil to each of the cylinders 20 and 22, and a cargo handling motor 26 that drives the hydraulic pump 25. The forklift 10 includes a traveling motor 27 that drives the rear wheel 15. The forklift 10 includes a control device 28 mounted on the vehicle body 11. The control device 28 as a control unit includes a storage unit 29 in which a program for controlling the forklift 10 and the like are stored. The forklift 10 of the present embodiment is an unmanned forklift that performs a traveling operation and a cargo handling operation based on a command from a higher-level control device (not shown) and a program stored in the storage unit 29.

  As shown in FIG. 2A, the forklift 10 includes a two-dimensional distance meter 31. The two-dimensional distance meter 31 of the present embodiment is a laser range finder. The two-dimensional distance meter 31 irradiates laser light while changing the irradiation angle in the horizontal direction. The two-dimensional distance meter 31 detects the distance to the target object from the reflected wave with respect to the emitted laser light. Specifically, a distance to a measurement point, which is a portion of the object that is irradiated with the laser light, is measured. The two-dimensional distance meter 31 outputs the measured distance to the control device 28 in association with the irradiation angle.

  One of the two forks 23 includes a storage section 33 in which the two-dimensional distance meter 31 is stored. The accommodating portion 33 is provided at the tip 23 a of the fork 23. The accommodating portion 33 is open at the tip of the fork 23. The housing portion 33 is closed by a closing member 34 made of a material through which laser light is transmitted. Thus, the two-dimensional distance meter 31 is located at the tip 23 a of the fork 23.

  As shown in FIG. 2B, the forklift 10 includes four sensors 40 on the upper surface of the fork 23. Two sensors 40 are provided for each fork 23. The sensor 40 of the present embodiment is a limit sensor that is turned on by contact and turned off by contact release. The sensor 40 outputs a detection result to the control device 28.

  As shown in FIG. 1, the forklift 10 stacks the post pallets 50 in the loading place F. The post pallet 50 includes a mounting plate 51 having a rectangular plate shape having long sides and short sides, and four columns 52. The load 55 is mounted on the mounting table 51.

  The four columns 52 are provided near corners of the mounting table 51, respectively. The column 52 includes a column 53 and a pedestal 54 having a larger sectional area in a direction perpendicular to the axial direction than the column 53. The pedestal 54 is provided at one end of the pillar 53. The columns 52 are provided so as to protrude from both sides of the mounting table 51. The post pallet 50 is arranged so that the pedestal 54 is located below. When stacking the post pallets 50, the post pallets 50 are stacked so that the columns 52 overlap each other.

  Hereinafter, the post pallet 50 already placed in the loading place F will be described as a first post pallet 50A, and the post pallet 50 stacked on the first post pallet 50A will be described as a second post pallet 50B. 3 to 6 schematically show the forklift 10.

  As shown in FIG. 3A, when stacking the second post pallet 50B on the first post pallet 50A, the control device 28 is between the columns 52 of the second post pallet 50B, and The rear wheel 15 is controlled so that the fork 23 is inserted into a region below the mounting table 51. In the present embodiment, the fork 23 is inserted between the columns 52 having a long interval, that is, between the columns 52 arranged along the long side of the mounting table 51 among the plurality of columns 52.

  When the fork 23 is inserted between the columns 52, the distal end 23a of the fork 23 projects outside the second post pallet 50B in plan view. Further, each sensor 40 provided on the fork 23 is located in the vicinity of each column 52 on the second post pallet 50B (for example, right next to each column 52). That is, the four sensors 40 are provided corresponding to the four columns 52, respectively.

  The control device 28 raises and lowers the fork 23 by controlling the supply and discharge of hydraulic oil to and from the lift cylinder 20. Then, the upper surface of the fork 23 supports the lower surface of the mounting table 51. Thus, the fork 23 supports the second post pallet 50B.

The control device 28 controls the rear wheel 15 to move the forklift 10 to a position near the first post pallet 50A.
As shown in FIG. 3B, the control device 28 controls the supply and discharge of the hydraulic oil to and from the lift cylinder 20 to raise the second post pallet 50B higher than the first post pallet 50A. The control device 28 moves the second post pallet 50B to a position directly above the first post pallet 50A by controlling the supply and discharge of hydraulic oil to and from the reach cylinder 22.

  As shown in FIG. 3C, the control device 28 controls the supply and discharge of the hydraulic oil to and from the lift cylinder 20 so that the support post 52 of the first post pallet 50A is attached to the support post 52 of the second post pallet 50B. The fork 23 is lowered to a position below the position where 52 contacts. The control device 28 pulls out the fork 23 from between the columns 52 of the second post pallet 50B by supplying and discharging the operating oil to and from the reach cylinder 22, and ends the stacking.

  When stacking the second post pallets 50B on the first post pallets 50A, the control device 28 of the present embodiment tilts the first post pallets 50A in the vehicle width direction and the center position in the vehicle width direction. Is calculated. Similarly, the control device 28 calculates the inclination of the second post pallet 50B with respect to the vehicle width direction and the center position with respect to the vehicle width direction at the time of scooping in which the second post pallet 50B is supported by the fork 23. That is, the control device 28 calculates the inclination of the placed post pallet 50 in the vehicle width direction and the center position in the vehicle width direction. The inclination of the first post pallet 50A with respect to the vehicle width direction is an inclination on a plane (on a horizontal plane).

  The calculation of the inclination and center position of the first post pallet 50A and the calculation of the inclination and center position of the second post pallet 50B are performed by the same control. For this reason, the first post pallet 50A and the second post pallet 50B are collectively referred to as a post pallet 50, and the detection of the inclination and the center position of the post pallet 50 will be described.

  In the following description, “front”, “rear”, “left”, and “right” are “front”, “rear”, “left”, and “right” with respect to the forklift 10. That is, the direction in which the forklift 10 moves forward is “front”, and the direction in which the forklift 10 moves backward is “rear”.

  As shown in FIG. 4, when the forklift 10 moves to the vicinity of the post pallet 50, one of the two columns 52 located rearward is a first column 52 </ b> A, and the other is a second column 52 </ b> B. I do. In the present embodiment, for the sake of convenience of description, in a state where the post pallet 50 is tilted, the post 52 located at the rear is replaced with the first post 52A, and the post 52 located at the front of the first post 52A. The second support 52B is used. The first column 52A and the second column 52B are two columns of the four columns 52 located on the forklift 10 side.

  The two-dimensional distance meter 31 irradiates laser light while changing the irradiation angle in the horizontal direction. Among the plurality of irradiation angles, there are irradiation angles at which the laser beam hits each column 52 and irradiation angles at which the laser beam does not hit each column 52. When the laser beam does not hit the column 52, the two-dimensional distance meter 31 cannot measure the distance. Alternatively, a significantly longer distance is measured as compared with the case where the laser beam hits each of the columns 52. For this reason, the control device 28 can grasp the distance to the column 52 and the angle (irradiation angle) with the column 52 from the distance measured by the two-dimensional rangefinder 31.

  The laser beam emitted from the two-dimensional rangefinder 31 hits the four columns 52. The control device 28 recognizes that there are four columns 52 by the reflected waves from the four columns 52. The control device 28 according to the present embodiment is configured such that, based on the distance between the two pillars 52 located at the rear of the four pillars 52, that is, the first pillar 52A and the second pillar 52B, and the irradiation angle, the post pallet is used. The slope of 50 is calculated.

In this embodiment, the state where the laser light is irradiated to the right is the irradiation angle of 0 degree (reference). Hereinafter, an example of calculating the inclination of the post pallet 50 will be described.
Each of the columns 52A and 52B has a plurality of portions to be irradiated with the laser beam. Of the irradiation angles at which the laser beam shines on the first support 52A, the portion where the laser beam shines when the irradiation angle is the largest is defined as a measurement point A. Of the irradiation angles at which the laser beam shines on the second support 52B, a portion where the laser beam shines when the irradiation angle is the smallest is defined as a measurement point B. A point at which an auxiliary line extending in the left-right direction (vehicle width direction) from the measurement point A and an auxiliary line extending in the front-rear direction from the measurement point B intersects with each other. A line segment connecting the measurement point A and the measurement point B is a line segment AB, a line segment connecting the measurement point B and the intersection point C is a line segment BC, and a line segment connecting the intersection point C and the measurement point A is a line segment CA And

  Here, the line segment CA is a line segment extending in the left-right direction, and the line segment AB is a line segment connecting the column 52A and the column 52B. When the post pallet 50 is not inclined with respect to the vehicle width direction, that is, when the post pallet 50 and the forklift 10 are not inclined, the struts 52 are arranged in the left-right direction. A line segment extending to That is, the line segment AB and the line segment CA overlap (become the same line segment). On the other hand, when an inclination occurs between the post pallet 50 and the forklift 10, the line segment AB inclines according to the inclination of the post pallet 50. As a result, the angle between the line segment CA and the line segment AB becomes the inclination θ of the first post pallet 50A with respect to the vehicle width direction.

  The control device 28 obtains a distance L1 to the measurement point A and an irradiation angle θ1 when the laser beam irradiates the measurement point A from the distance measured by the two-dimensional rangefinder 31. Further, the control device 28 obtains a distance L2 to the measurement point B and an irradiation angle θ2 when the measurement point B is irradiated with the laser beam.

  The control device 28 calculates the length b of the line segment BC. The length b can be obtained from the following equation (1).

d1 is a dimension in the front-rear direction between the two-dimensional distance meter 31 and the first support 52A. d2 is the dimension in the front-rear direction between the two-dimensional distance meter 31 and the second support 52B. d1 can be obtained from the following equation (2). d2 can be obtained from the following equation (3).

Next, the control device 28 calculates the length a of the line segment AB. The length a can be obtained from the following equation (4).

Next, the control device 28 calculates the inclination θ from the following equation (5).

The control device 28 determines that the post pallet 50 is inclined with respect to the vehicle width direction by the angle of the inclination θ obtained from the equation (5). Further, the control device 28 determines that the position that bisects the length a is the center position P of the post pallet 50 in the vehicle width direction.

  Further, when raising the fork 23 supporting the second post pallet 50B, the control device 28 detects the height of the column 52 of the first post pallet 50A from the distance measured by the two-dimensional distance meter 31. ing. When the fork 23 is located below the upper surface of the column 52 of the first post pallet 50A, the laser beam emitted from the two-dimensional rangefinder 31 hits the column 52. When the fork 23 rises above the upper surface of the column 52 of the first post pallet 50A, the laser beam stops hitting the column 52. When the laser beam no longer hits the column 52, the distance is no longer measured by the two-dimensional rangefinder 31. Alternatively, an extremely long distance is measured as compared with the case where the laser beam hits the support 52. The control device 28 raises the fork 23, and when the distance is no longer measured by the two-dimensional distance meter 31, or when the distance measured by the two-dimensional distance meter 31 exceeds a predetermined threshold, The height of the fork 23 at this time is defined as the height of the column 52 of the first post pallet 50A. The threshold value is set to a value larger than the distance measured by the two-dimensional distance meter 31 when the laser beam hits the support 52. Therefore, the control device 28 can detect the height of the column 52 of the first post pallet 50A depending on whether or not the distance to the column 52 can be measured by the two-dimensional distance meter 31. The controller 28 raises the fork 23 from the detected height until the lower surface of the column 52 of the second post pallet 50B reaches a position slightly higher than the upper surface of the column 52 of the first post pallet 50A.

  When lowering the fork 23 and stacking the second post pallet 50B on the first post pallet 50A, the control device 28 checks whether the second post pallet 50B has been stacked normally. Confirm.

  When the fork 23 supports the second post pallet 50B, the lower surface of the mounting table 51 is in contact with the upper surface of the fork 23. Each sensor 40 is turned on by contact of the lower surface of the mounting table 51. Each sensor 40 is turned off when the contact between the lower surface of the mounting table 51 and the upper surface of the fork 23 is released. Therefore, the sensor 40 detects whether or not the second post pallet 50B is in contact with the fork 23.

  When all the posts 52 of the second post pallet 50B are stacked on the posts 52 of the first post pallet 50A, the upper surface of the fork 23 moves away from the lower surface of the mounting table 51. On the other hand, as shown in FIG. 6A and FIG. 6B, of the columns 52 of the second post pallet 50B, only some columns 52 are stacked on the columns 52 of the first post pallet 50A. In this case, the mounting table 51 also descends as the fork 23 descends. More specifically, as shown in FIG. 6C and FIG. 6D, of the mounting table 51 of the second post pallet 50B, the support 52 stacked on the support 52 of the first post pallet 50A. Is separated from the fork 23, and a portion separated from the support 52 stacked on the support 52 of the first post pallet 50A is lowered together with the fork 23. For this reason, when only some posts 52 of the second post pallet 50B are stacked on the posts 52 of the first post pallet 50A, some of the sensors 40 are turned on and some of the sensors 40 are turned off. Become.

  If all the posts 52 of the second post pallet 50B are not stacked on all the posts 52 of the first post pallet 50A, all the sensors 40 are kept on when the fork 23 is lowered. Therefore, when the control device 28 detects that all the sensors 40 are turned off when the fork 23 is lowered, it is determined that the second post pallet 50B has been normally stacked on the first post pallet 50A. to decide.

  When the at least one sensor 40 is maintained on when the fork 23 is lowered, the control device 28 controls the at least one support 52 of the second post pallet 50B to support the support 52 of the first post pallet 50A. It is determined that the fork 23 has not been loaded, and the lowering of the fork 23 is stopped.

Next, the operation of the forklift 10 will be described.
When stacking the second post pallets 50B, the control device 28 detects the inclination θ of the first post pallets 50A. As shown in FIG. 5, the control device 28 controls the rear wheels 15 so that the vehicle body 11 is inclined by the same angle as the inclination θ with respect to the vehicle width direction. The control device 28 controls the rear wheels 15 so that the center position of the vehicle body 11 in the vehicle width direction matches the center position P of the first post pallet 50A. From this state, by stacking the second post pallets 50B on the first post pallets 50A, the columns 52 of the second post pallets 50B are stacked on the columns 52 of the first post pallets 50A.

  In addition, when the second post pallet 50B is scooped, the control device 28 detects the inclination θ of the second post pallet 50B. The control device 28 controls the rear wheels 15 so that the vehicle body 11 is inclined at the same angle as the inclination θ with respect to the vehicle width direction. The control device 28 controls the rear wheels 15 so that the center position of the vehicle body 11 in the vehicle width direction coincides with the center position P of the second post pallet 50B. By scooping the second post pallet 50B from this state, the second post pallet 50B is prevented from being supported by the fork 23 while being inclined with respect to the vehicle width direction.

Therefore, according to the above embodiment, the following effects can be obtained.
(1) The control device 28 calculates the inclination θ and the center position P of the first post pallet 50A with respect to the vehicle width direction from the distance from the two-dimensional distance meter 31 to each of the columns 52A and 52B and the irradiation angle. . When stacking the second post pallets 50B, the rear wheels 15 are controlled in accordance with the inclination θ and the center position P of the first post pallets 50A. In addition, the center of the vehicle body 11 is aligned with the center position P of the first post pallet 50A. By stacking the second post pallets 50B on the first post pallets 50A in this state, the columns 52 of the second post pallets 50B can be stacked on the columns 52 of the first post pallets 50A. That is, the post pallets 50 can be stacked.

  (2) The two-dimensional distance meter 31 is provided at the tip 23a of the fork 23. The tip 23 a of the fork 23 projects outside the post pallet 50 when inserted between the columns 52. For this reason, by providing the two-dimensional distance meter 31 at the tip portion 23a of the fork 23, it is possible to suppress the laser beam from hitting the support posts 52 of the second post pallet 50B. Therefore, it is easy to detect the distance from the first post pallet 50A.

  (3) The forklift 10 includes a sensor 40 on the upper surface of the fork 23. When lowering the fork 23 supporting the second post pallet 50B and all the sensors 40 are turned off, the controller 28 normally stacks the second post pallet 50B on the first post pallet 50A. Judge that Therefore, the sensor 40 can detect whether or not the post pallets 50 are stacked.

  (4) The control device 28 detects the height of the column 52 of the first post pallet 50A when raising the fork 23. The control device 28 can raise the fork 23 in accordance with the height of the column 52 of the first post pallet 50A. Therefore, it is possible to prevent the fork 23 from rising excessively or insufficiently raising the fork 23.

  (5) The controller 28 calculates the inclination θ and the center position P of the second post pallet 50B with respect to the vehicle width direction at the time of scooping. Therefore, the second post pallet 50B is suppressed from being supported by the fork 23 while being inclined with respect to the vehicle width direction.

  (6) The inclination θ and the center position P of the first post pallet 50A with respect to the vehicle width direction are calculated from the two columns 52 located on the forklift 10 side among the four columns 52. Therefore, it is easy to calculate the inclination θ and the center position P of the first post pallet 50A with respect to the vehicle width direction.

Note that the embodiment may be modified as follows.
The controller 28 only needs to detect the inclination θ and the center position P of the first post pallet 50A, and does not have to detect the inclination θ and the center position P of the second post pallet 50B during the scooping.

  The control device 28 does not have to detect the height of the column 52 of the first post pallet 50A. In this case, for example, the control device 28 may raise the fork 23 to a predetermined height, or store the number of post pallets 50 placed in the loading area F, and adjust the fork 23 according to this number. The height to raise may be determined.

○ At least two sensors 40 may be provided.
O The sensor 40 may not be provided. In this case, a member other than the sensor 40 may detect that the second post pallet 50B has been normally stacked on the first post pallet 50A. Further, it is not necessary to detect that the second post pallet 50B is normally stacked on the first post pallet 50A.

The two-dimensional distance meter 31 may be provided on at least one of the forks 23, and may be provided on both of the forks 23.
The two-dimensional distance meter 31 may use an ultrasonic wave as long as it can measure the distance to the object at each irradiation angle.

-The forklift may be a forklift operated by a passenger (manned forklift).
The post pallet 50 may have three or more columns 52. Then, the inclination and center position of the post pallet may be detected from two of the plurality of columns. At this time, it is preferable to detect the inclination and the center position of the post pallet from the two columns located on the forklift 10 side.

  In the case where the number of columns is eight, that is, in the case of a post pallet in which one column is added between the four columns 52 of the post pallet 50 of the embodiment, of the three columns located on the forklift 10 side, The inclination and center position of the post pallet can be detected from any two columns. The inclination of the post pallet can be calculated from the inclination of any two columns by the same calculation method as in the embodiment. When the center position of the post pallet is calculated from the center column of the three columns and one of the columns adjacent to the column, the center position is calculated using the inclination. The storage unit 29 stores, in advance, the relationship between the center position of the post pallet and the columns. The control device 28 calculates the inclination of the post pallet, and calculates the center position of the post pallet from the calculated inclination. That is, in the case where the center position is calculated by using a pillar whose center position of the post pallet does not match the center position of the pillars, the center position can be calculated by using the inclination. Note that the same calculation can be performed for a post pallet having a number of columns other than eight.

The inclination and center position of the post pallet 50 may be calculated from the two pillars 52 located in front of the four pillars 52.
The inclination and center position of the post pallet 50 may be calculated from three or more columns 52 among the plurality of columns 52.

  The sensor 40 may be a sensor other than the limit sensor. For example, a sensor that detects whether or not the second post pallet 50B is in contact with the fork by measuring the distance to the second post pallet 50B may be used.

  In the embodiment, an example of calculating the inclination of the post pallet 50 from the distance to each of the columns 52A and 52B and the irradiation angle has been described, but which direction is used as the reference (0 degree) of the irradiation angle, The inclination can be calculated in various modes depending on whether the auxiliary line is assumed. For this reason, the inclination may be calculated in a manner different from the embodiment.

  The measurement point A may be a portion where the laser beam irradiates at any irradiation angle as long as the laser beam irradiates the first support 52A. For example, the measurement point A may be a portion irradiated with the laser beam when the irradiation angle is smallest among the irradiation angles of the laser beam of the first support 52A. The measurement point B may be a portion irradiated with the laser beam at any irradiation angle as long as the irradiation angle irradiates the second support 52B with the laser beam. For example, the measurement point B may be a portion where the laser beam shines when the irradiation angle is the largest among the irradiation angles where the laser beam shines on the second support 52B.

  DESCRIPTION OF SYMBOLS 10 ... Forklift, 23 ... Fork, 23a ... Tip part, 28 ... Control device (control part), 31 ... Two-dimensional distance meter, 40 ... Sensor, 50 ... Post pallet, 50A ... 1st post pallet, 50B ... 2nd Post pallet, 52... Support, 52A... First support, 52B.

Claims (5)

A forklift for stacking a post pallet including a mounting table on which a load is mounted and a plurality of columns,
A fork for supporting a second post pallet stacked on the first post pallet placed thereon;
A two-dimensional distance meter that is provided at a tip of the fork and measures a distance from the first post pallet for each of a plurality of irradiation angles;
When stacking the second post pallet on the first post pallet, the distance from at least two of the plurality of columns to the two-dimensional distance meter and the irradiation angle from the vehicle width direction of the forklift And a control unit for calculating the inclination of the first post pallet with respect to the first post pallet and the center position. The first post pallet comprises four of the columns,
The control unit is configured to, when stacking the second post pallet on the first post pallet, determine a distance between the two columns located on the forklift side and the two-dimensional distance meter, and an irradiation angle. The forklift according to claim 1, wherein the inclination of the first post pallet with respect to the vehicle width direction and the center position are calculated. At least two sensors for detecting whether the second post pallet is in contact with the fork,
The controller, when lowering the fork supporting the second post pallet, if all the sensors do not detect that the second post pallet is in contact with the fork, The forklift according to claim 1 or 2, wherein it is determined that all the columns of the second post pallet are stacked on the columns of the first post pallet.   The said control part detects the height of the said support | pillar based on whether the distance to the said support | pillar can be measured by the said two-dimensional distance meter, when raising the said fork, The any one of Claims 1-3. A forklift according to one of the preceding claims.   The controller controls a distance between at least two of the plurality of columns to the two-dimensional distance meter and a vehicle width of the forklift based on an irradiation angle when the rake for supporting the second post pallet on the fork. The forklift according to any one of claims 1 to 4, wherein a tilt of the first post pallet with respect to a direction and a center position are calculated.