forklift

Abstract

To provide a forklift with a simple structure capable of reducing a dimension in a lateral direction, as well as, adjusting positions of forks in the lateral direction when a load is placed at a place facing the forks.SOLUTION: A forklift F comprises: a pair of right and left forks 2R, 2L; a side shift device 4 for moving the forks 2R, 2L in a lateral direction Y; an area sensor 5 provided so as not to protrude in the lateral direction Y from a vehicle body and capable of detecting an object located in preset areas; and a sensor controller 6A configured to control the area sensor 5 to cause the area sensor 5 to scan a right area RA located on a right side of the forks 2R, 2L and a left area LA located on a left side of the forks 2R, 2L, which are defined as the preset areas; and a shift controller 6B configured to control the side shift device 4 on the basis of a detection result of the area sensor 5, so as to adjust positions of the forks 2R, 2L in the lateral direction Y.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a forklift truck in which the position of the forks can be adjusted in the left-right direction. [Background technology]

[0002] Patent Document 1 describes a forklift equipped with a pair of left and right forks, a side shift cylinder (side shift device) that moves the forks left and right, and a cargo handling control device that controls cargo handling. The cargo handling control device is equipped with a pair of left and right laser distance sensors that detect the distance to an object located ahead, and controls the side shift cylinder based on the detection values ​​of the laser distance sensors. In other words, the side shift cylinder moves the pair of forks left and right based on the object detection results obtained by the laser distance sensors.

[0003] However, in the configuration of Patent Document 1, it was necessary to increase the distance between the pair of left and right laser distance sensors so that the laser light emitted and received by the laser distance sensors would not be blocked by the load supported by the forks. This meant that the size of the forklift in the left-right direction could not be reduced, which caused the inconvenience of hindering the forklift's travel through narrow passages. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 7156174 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 reduce the left-right dimension and that allows the position of the forks to be adjusted left-right with a simple configuration when placing a load opposite the forks. [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 vehicle body that travels on a road surface; a pair of forks that extend in the front-to-rear direction and are spaced apart in the left-to-right direction; a side shift device that moves the pair of forks in the left-to-right direction; an area sensor that is arranged so as not to protrude from the vehicle body in the left-to-right direction and is 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 right area located to the right of the pair of forks and a left area located to the left of the pair of forks as the area; and a shift control unit that controls the side shift device based on the detection result by the area sensor to adjust the position of the pair of forks in the left-to-right direction.

[0007] In addition, it is preferable that the range of the right area is changeable, and the sensor control unit controls the area sensor to expand the range of the right area to the right in order to detect the object located to the right of the location opposite the pair of forks.

[0008] In addition, it is preferable that the sensor control unit causes the area sensor to scan multiple right areas with different ranges in a predetermined order, and the shift control unit calculates the amount of movement of the pair of forks in the left-right direction based on an ordinal number indicating the right area in which the object is detected.

[0009] In addition, it is preferable that the range of the left area is changeable, and the sensor control unit controls the area sensor to expand the range of the left area to the left in order to detect the object located to the left of the location opposite the pair of forks.

[0010] In addition, it is preferable that the sensor control unit causes the area sensor to scan multiple left areas with different ranges in a predetermined order, and the shift control unit calculates the amount of movement of the pair of forks in the left-right direction based on an ordinal number indicating the left area in which the object is detected. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a forklift truck that can reduce the left-right dimensions and that allows the position of the fork in the left-right direction to be adjusted with a simple configuration when placing a load opposite the fork. [Brief explanation of the drawings]

[0012] [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] FIG. 10(A) is a schematic diagram showing the ranges of a plurality of right areas that have been set in advance, and FIG. 10(B) is a schematic diagram showing the ranges of a plurality of left areas that have been set in advance. [Figure 4] 10 is a flowchart showing a flow of a side shift process performed by the forklift according to the embodiment. [Figure 5] FIG. 10 is a plan view of the forklift and the rack, showing an example of a state in which an object located in the right area is detected. [Figure 6] FIG. 10 is a plan view of a forklift and a rack, showing an example of a state in which objects located in the right area and the left area are detected. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the present invention will be described with reference to the drawings. Note that the front-rear direction X, left-right direction Y, and up-down direction Z indicated by arrows in the drawings are linear directions that are perpendicular to one another.

[0014] 1(A) and 1(B), the forklift F according to this embodiment is an unmanned reach forklift, and includes a vehicle body 1, a pair of forks 2R, 2L, a lift device 3, a side shift device 4, an area sensor 5, and a control device 6. The forklift F transports a load M supported by the forks 2R, 2L, and performs load placement work by placing the load M in a predetermined location.

[0015] The vehicle body 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 travel route to a predetermined target point. That is, the vehicle body 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 travel route, and a braking device that brakes to stop the vehicle from traveling.

[0016] The pair of forks 2R, 2L are claws that extend in the front-rear direction X and are spaced apart in the left-right direction Y. The forks 2R, 2L are inserted into a pair of insertion holes (not shown) of the load M to support the load M.

[0017] The lift device 3 moves the forks 2R, 2L in the vertical direction Z (i.e., raises and lowers the forks 2R, 2L) relative to the vehicle body 1. The lift device 3 also moves the side shift device 4 and the area sensor 5 in the vertical direction Z together with the forks 2R, 2L.

[0018] The side shift device 4 moves the pair of forks 2R, 2L in the left-right direction Y relative to the vehicle body 1 without changing the distance between the forks 2R, 2L. In other words, the side shift device 4 can move the forks 2R, 2L in the left-right direction Y while the vehicle body 1 is stopped. In addition, the side shift device 4 moves the area sensor 5 in the left-right direction Y together with the forks 2R, 2L.

[0019] The area sensor 5 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 5 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 5 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 5 as a reference point. Then, when the reflection point of the laser light is included in the set area A, the area sensor 5 outputs a signal indicating that an object located in the set area A has been detected.

[0020] The area sensor 5 is provided so as not to protrude from the vehicle body 1 in the left-right direction Y. In this embodiment, the area sensor 5 is provided between the pair of forks 2R, 2L and on the left-right center line CL of the forks 2R, 2L. The area sensor 5 is also provided below the forks 2R, 2L so that the laser light is not blocked by the load M.

[0021] The control device 6 controls the side shift device 4 based on the detection result by the area sensor 5. As shown in Fig. 2(A), the control device 6 is made up of a sensor control unit 6A and a shift control unit 6B.

[0022] The sensor control unit 6A controls the area sensor 5 to scan the set area A, which includes a central area CA, a right area RA, and a left area LA (see FIG. 2(B) for all of these), which are areas on the tip side of the forks 2R and 2L (i.e., areas facing the forks 2R and 2L). As shown in FIG. 2(B), the central area CA is an area located between the forks 2R and 2L. The right area RA is an area located to the right of the forks 2R and 2L. The left area LA is an area located to the left of the forks 2R and 2L. The sensor control unit 6A changes the range of the right area RA by switching between multiple right areas RA, which will be described later, and changes the range of the left area LA by switching between multiple left areas LA, which will be described later.

[0023] The shift control unit 6B adjusts the positions of the forks 2R, 2L in the left-right direction Y by controlling the side shift device 4 based on the detection results of the area sensor 5. Specifically, when an object is detected in at least one of the right area RA and the left area LA, the shift control unit 6B determines the amount of movement of the forks 2R, 2L in the left-right direction Y, and operates the side shift device 4 so that the forks 2R, 2L move by that amount.

[0024] A plurality of right areas RA and left areas LA that are set in advance will be described with reference to Fig. 3. Fig. 3(A) shows the 1st to 31st right areas RA1 to RA 31 3B shows a schematic diagram of a plurality of left areas LA, 1st to 31st left areas LA1 to LA 31 3. The reference line SL in FIG. 3 indicates a position spaced a predetermined distance (for example, 1350 mm) forward from the area sensor 5. In FIG. 3, the 4th to 30th right areas RA4 to RA 30 and left area LA4~LA 30 The symbols indicating the above are omitted.

[0025] As shown in FIG. 3A, the first right area RA1 extends forward and to the right of the area sensor 5, and includes an area to the right of the right fork 2R in order to detect an object located to the right of the location facing the forks 2R and 2L. 31 is configured to be an area obtained by expanding the first right area RA1 by 10 mm to the right on the reference line SL.

[0026] As shown in FIG. 3B, the first left area LA1 extends forward and to the left of the area sensor 5, and includes an area to the left of the left fork 2L in order to detect an object located to the left of the location facing the forks 2R and 2L. 31 is configured to be an area obtained by expanding the first left area LA1 by 10 mm to the left on the reference line SL.

[0027] The flow of the side shift process performed by the forklift F will be described with reference to FIG. The side shifting process shown in FIG. 4 is started when the forks 2R, 2L are supporting the load M and the area sensor 5 is spaced a predetermined distance from the place where the load M should be placed in the front-rear direction X.

[0028] As shown in FIG. 4, the sensor control unit 6A causes the area sensor 5 to scan the central area CA (step S1), and determines whether or not an object has been detected in the central area CA (step S2).

[0029] If an object is detected in the central area CA (step S2: YES), the forklift F determines that there is an obstacle that prevents the load M from being placed, terminates the side shifting process without operating the side shift device 4, and stops the load placement operation. In this case, the forklift F notifies the manager of the presence of an obstacle using an alarm device (not shown) (for example, an acoustic device that emits sound, a light-emitting device that emits light, or a communication device that communicates with an external device).

[0030] If no object is detected in the central area CA (step S2: NO), the sensor control unit 6A causes the area sensor 5 to scan the right area RA (step S3) and also causes the area sensor 5 to scan the left area LA (step S4). That is, the right area RA and the left area LA are scanned simultaneously.

[0031] In step S3, the sensor control unit 6A controls the area sensor 5 to scan a plurality of right areas RA with different ranges in a predetermined order in order to detect an object located to the right of the location facing the forks 2R and 2L, thereby expanding the range of the right area RA to the right. Specifically, the sensor control unit 6A controls the area sensor 5 to scan the right areas RA in order from the first right area RA1, and also controls the area sensor 5 to scan the right areas RA in order from the "N"th right area RA. N If an object is detected in the "N+1"th or later right area RA N+1 ~RA 31 In other words, when an object is detected in any right area RA, the scanning in step S3 is terminated in order to reduce the time.

[0032] In step S4, the sensor control unit 6A controls the area sensor 5 to scan a plurality of left areas LA with different ranges in a predetermined order in order to detect an object located to the left of the location facing the forks 2R and 2L, thereby expanding the range of the left area LA to the left. Specifically, the sensor control unit 6A controls the area sensor 5 to scan the left areas LA in order from the first left area LA1, and also controls the area sensor 5 to scan the left areas LA in order from the "N"th left area LA. N If an object is detected in the "N+1"th or later left area LA N+1 ~LA 31 In other words, when an object is detected in any left area LA, the scanning in step S4 is terminated in order to reduce the time.

[0033] Next, the shift control unit 6B determines whether an object is detected in either the right area RA or the left area LA (step S5). Furthermore, if an object is detected in either the right area RA or the left area LA (step S5: YES), the shift control unit 6B determines whether an object is detected in the first right area RA1 or left area LA1 (step S6).

[0034] If no object is detected in either the right area RA or the left area LA (step S5: NO), the forklift F performs a load placement operation by placing the load M in a location opposite the forks 2R, 2L without operating the side shift device 4.

[0035] Also, if an object is detected in the first right area RA1 or left area LA1 (step S6: YES), the shift control unit 6B operates the side shift device 4 to move the forks 2R, 2L by a certain amount in order to increase the distance between the detected object and the forks 2R, 2L in the left-right direction Y (step S7).

[0036] Specifically, when an object is detected in the first right area RA1, the shift control unit 6B detects an object in the second and subsequent right areas RA2 to RA 31 The side shift device 4 is operated so that the forks 2R, 2L move leftward by a preset amount so that an object is detected in one of the first left area LA1. Also, when an object is detected in the first left area LA1, the shift control unit 6B moves the forks 2R, 2L leftward by a preset amount so that an object is detected in one of the second and subsequent left areas LA2 to LA. 31 The side shift device 4 is operated so that the forks 2R, 2L move to the right by a preset amount so that an object is detected by either of the above. After the forks 2R, 2L have moved in this way in step S7, step S3 and subsequent steps are repeated.

[0037] If an object is detected in either the right area RA or the left area LA (step S5: YES), and if an object is not detected in the first right area RA1 or left area LA1 (step S6: NO), the shift control unit 6B calculates the movement amount of the forks 2R and 2L (step S8). 31 and the second and subsequent left areas LA2~LA 31 When an object is detected in either of the above, the amount of movement of the forks 2R and 2L is calculated.

[0038] Specifically, when an object is detected in both the right area RA and the left area LA, the shift control unit 6B calculates "D" (unit: mm), which is the amount of movement with the right being the positive direction, based on the ordinal numbers indicating the right area RA and left area LA in which the object was detected, according to the following (Equation 1). Note that "R" in (Equation 1) is the ordinal number of the right area RA in which the object was detected, and "L" in (Equation 1) is the ordinal number of the left area LA in which the object was detected. For example, if no object is detected in the first to fourth right areas RA1 to RA4, but an object is detected in the fifth right area RA5, "R" is "5."

number

[0039] Furthermore, when an object is detected only in the right area RA, the shift control unit 6B calculates "D" (unit: mm), which is a movement amount with the right being the positive direction, based on the ordinal number indicating the right area RA where the object is detected, according to the following (Equation 2). Note that "R" in (Equation 2) is the ordinal number of the right area RA where the object is detected, and "X" in (Equation 2) R " is the ordinal number of the target area. For example, if the target is to detect an object in the fifth right area RA5, "X R " is "5".

number

[0040] Furthermore, when an object is detected only in the left area LA, the shift control unit 6B calculates "D" (unit: mm), which is the amount of movement with the right being the positive direction, based on the ordinal number indicating the left area LA where the object was detected, according to the following (Equation 3). Note that "L" in (Equation 3) is the ordinal number of the left area LA where the object was detected, and "X" in (Equation 3) L " is the ordinal number of the target area. For example, if the target is to detect an object in the fifth left area LA5, "X L " is "5".

number

[0041] Then, the shift control unit 6B operates the side shift device 4 so that the forks 2R, 2L move by the movement amount calculated in step S8 (step S9). After the side shift device 4 operates in this manner, the forklift F sets the place opposite the forks 2R, 2L as a load storage area and places the load M there.

[0042] Next, a specific example of the operation of the forklift F will be described with reference to Figures 5 and 6. Figures 5 and 6 show the state at the start of side shifting processing, in which the vehicle body 1 stops traveling at a position where the rack R and the area sensor 5 face each other at a predetermined distance, and the area sensor 5 is positioned above the beam 12.

[0043] The rack R shown in Figures 5 and 6 is a table for storing loads M and includes support columns 11R and 11L, a beam 12, and a sub-beam 13. The support columns 11R and 11L are vertical members extending in the up-down direction Z. The beam 12 is a horizontal member extending in the left-right direction Y and connects the pair of left and right support columns 11R and 11L. The sub-beam 13 is a horizontal member extending in the front-rear direction X and connects the pair of front and rear beams 12. The beam 12 and sub-beam 13 function as shelves that support the loads M.

[0044] 5 shows a state in which an object is detected in only one of the right area RA and the left area LA. Specifically, FIG. 5 shows a state in which no object is detected in the first and second right areas RA1 and RA2, and a support pillar 11R is detected as an object in the third right area RA3, and the first to 31st left areas LA1 to LA 31 In this case, the movement amount of the forks 2R and 2L is calculated according to (Equation 2). R If "D = 5" is preset (i.e., the fifth right area RA5 is the target area), then the calculated movement amount is "D = -20". Therefore, the side shift device 4 moves the forks 2R, 2L 20 mm to the left. In this way, the forks 2R, 2L move so that the support 11R is positioned in the target area, and it becomes possible to place the load M at a predetermined distance from the support 11R.

[0045] 6 shows a state in which an object is detected in both the right area RA and the left area LA. Specifically, FIG. 6 shows the first to eleventh right areas RA1 to RA 11 No object is detected in the 12th right area RA 12 In the state where load N is detected as an object in the 1st to 9th left areas LA1 to LA9, no object is detected in the 10th left area LA 10 1 shows a state in which the support pillar 11L is detected as an object. In this case, according to (Equation 1), the movement amount of the forks 2R, 2L is calculated as "D=10". Therefore, the side shift device 4 moves the forks 2R, 2L by 10 mm to the right. In this way, the forks 2R, 2L move so that the left-right center line CL is positioned at the midpoint between the support pillar 11L and the load N, making it possible to place the load M at an equal distance from the support pillar 11L and the load N.

[0046] In this embodiment, the following effects are obtained. (1) The area sensor 5 is disposed so as not to protrude from the vehicle body 1 in the left-right direction Y. This configuration allows the forklift F to have a small dimension in the left-right direction Y so that it can travel through narrow passages. The sensor control unit 6A controls the area sensor 5 to scan a right area RA located to the right of the forks 2R and 2L and a left area LA located to the left of the forks 2R and 2L. The shift control unit 6B controls the side shift device 4 based on the detection results of the area sensor 5 to adjust the positions of the forks 2R and 2L in the left-right direction Y. This configuration allows for detection of an object adjacent to a location facing the forks 2R and 2L in the limited right area RA and left area LA. This simplifies the process for detecting an object compared to, for example, a configuration that scans the entire area in front of the forks 2R and 2L to detect an object. Therefore, when placing a load M in a location facing the forks 2R and 2L, an expensive configuration with high computing power is not required, and the position of the forks 2R and 2L can be adjusted with a simple configuration.

[0047] (2) The sensor control unit 6A controls the area sensor 5 to expand the range of the right area RA to the right. With this configuration, if an object is detected early in the right area RA, scanning of the right area RA can be terminated, thereby shortening the scanning time.

[0048] (3) The shift control unit 6B calculates the amount of movement of the forks 2R, 2L in the left-right direction Y based on the ordinal number indicating the right area RA where the object was detected. With this configuration, the amount of movement of the forks 2R, 2L in the left-right direction Y can be determined without calculating the distance from the area sensor 5 in the left-right direction Y to the object detected in the right area RA.

[0049] (4) The sensor control unit 6A controls the area sensor 5 to expand the range of the left area LA to the left. With this configuration, if an object is detected early in the left area LA, scanning of the right area RA can be terminated, thereby shortening the scanning time.

[0050] (5) The shift control unit 6B calculates the amount of movement of the forks 2R, 2L in the left-right direction Y based on the ordinal number indicating the left area LA where the object was detected. With this configuration, the amount of movement of the forks 2R, 2L in the left-right direction Y can be determined without calculating the distance from the area sensor 5 in the left-right direction Y to the object detected in the left area LA.

[0051] 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.

[0052] The location of the area sensor 5 may be changed as appropriate as long as it does not protrude from the vehicle body 1 in the left-right direction Y. For example, the area sensor 5 may be provided to the right of the right fork 2R or to the left of the left fork 2L. The location of the area sensor 5 may also be changed as appropriate as long as the laser light is not blocked by the load M. The area sensor 5 may be provided above the forks 2R and 2L. [Explanation of symbols]

[0053] 1 Vehicle body 2R,2L fork 3 Lifting device 4 Side shift device 5 Area Sensor 6. Control device 6A Sensor control unit 6B Shift control section F Forklift M,N load R rack X Anteroposterior direction Y left / right direction Z vertical direction CA Central Area CL Left and right center line LA, LA1~LA 31 Left Area RA, RA1~RA 31 Right Area SL Reference Line

Claims

1. A vehicle body that runs on a road surface; a pair of forks extending in the front-rear direction and spaced apart in the left-right direction; a side shift device that moves the pair of forks in the left-right direction; an area sensor that is provided so as not to protrude from the vehicle body in the left-right direction and that is 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 right area located to the right of the pair of forks and a left area located to the left of the pair of forks as the areas; a shift control unit that adjusts positions of the pair of forks in the left-right direction by controlling the side shift device based on a detection result by the area sensor, The range of the right area is changeable, The sensor control unit controls the area sensor to expand the range of the right area to the right in order to detect the object located to the right of the location facing the pair of forks. A forklift characterized by:

2. the sensor control unit causes the area sensor to scan the right areas having different ranges in a predetermined order; The shift control unit calculates a movement amount for moving the pair of forks in the left-right direction based on an ordinal number indicating the right area where the object is detected.

2. The forklift according to claim 1.

3. A vehicle body that runs on a road surface; a pair of forks extending in the front-rear direction and spaced apart in the left-right direction; a side shift device that moves the pair of forks in the left-right direction; an area sensor that is provided so as not to protrude from the vehicle body in the left-right direction and that is 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 right area located to the right of the pair of forks and a left area located to the left of the pair of forks as the areas; a shift control unit that adjusts positions of the pair of forks in the left-right direction by controlling the side shift device based on a detection result by the area sensor, The range of the left area is changeable, The sensor control unit controls the area sensor to widen the range of the left area to the left in order to detect the object located to the left of the location facing the pair of forks. A forklift characterized by:

4. the sensor control unit causes the area sensor to scan the plurality of left areas having different ranges in a predetermined order; The shift control unit calculates a movement amount for moving the pair of forks in the left-right direction based on an ordinal number indicating the left area where the object is detected.

4. The forklift according to claim 3.

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