JP3690716B2 - forklift - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a forklift, and more particularly to a forklift that performs a cargo handling operation in a rack passage disposed in a warehouse or the like.
[0002]
[Prior art]
FIG. 4 is a diagram showing how this type of forklift performs a cargo handling operation in a warehouse.
In the figure, 1 is a forklift, 2 is a mast that is raised and lowered during a cargo handling operation, 3 is a pair of mast guide rollers that are rotatably provided on both sides of the mast 2, and 4 and 5 are racks that store luggage, 6 Is a path between the racks 4 and 5, and 7 is a frame of the rack.
[0003]
When taking out a load from the racks 4 and 5 or storing a load in the racks 4 and 5, the forklift 1 is moved into the passage 6 and travels to a predetermined position. In this case, as shown in FIG. 5, since the mast guide roller 3 rotates in contact with the frames 7 of the racks 4 and 5, the forklift 1 is guided by the mast guide roller 3 and travels straight in the passage 6. . When the predetermined position is reached, the mast 2 is raised, and a cargo handling operation for taking out the luggage from the shelves of the racks 4 and 5 and storing the luggage on the shelves is performed.
[0004]
By the way, in the forklift that performs the cargo handling work in the rack passage as described above, the height of the mast 2 at the time of raising and lowering may be 8 to 10 m. In this case, the stability of the vehicle body becomes a problem. The balance in the front-rear direction of the vehicle body can be relatively easily ensured by installing a counterweight. However, regarding the balance in the left-right direction, it is difficult to secure the balance because the width of the vehicle body is narrow compared to the width of the front and rear, and it is difficult to obtain sufficient stability even if the dimensions of the wheel base and tread are changed It is. For this reason, conventionally, the load when carrying out the cargo handling operation at high lift is limited to a certain level or less.
[0005]
[Problems to be solved by the invention]
However, as can be seen from FIG. 5, as long as the forklift 1 performs a cargo handling operation in the rack path 6, the forklift 1 is attached to the rack 4 by the contact between the mast guide roller 3 and the frames 7 of the racks 4 and 5. There is no risk of falling sideways with 5 as a support. On the other hand, when the forklift 1 is outside the passage 6, there is no support, but it is not necessary to raise the mast 2 to the position of high elevation outside the passage.
[0006]
Nevertheless, in the past, assuming that the mast has been raised to the elevated position outside the rack passage, the cargo handling load has been limited as described above to ensure safety. Therefore, there is an unreasonable fact that the load in the cargo handling operation in the rack passage that does not need to be restricted is restricted.
[0007]
The present invention solves the above-described problems, and provides a forklift that does not unnecessarily limit the loading load in the rack passage and can ensure safety even outside the rack passage. It is an issue.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is provided with a sensor that detects a rack that exists in the vicinity of the mast guide roller, and when this sensor detects a rack, the mast is allowed to rise to a higher height. If no rack is detected, the mast is not allowed to rise.
[0009]
In this way, when the forklift is in the rack passage, the rack is detected by the sensor, so the mast can be raised to the elevated position, but if the forklift is outside the rack passage, Is not detected, the mast cannot be raised to the elevated position. Therefore, there is no possibility that the vehicle body rolls over due to the mast rising outside the rack passage, so that it is not necessary to limit the load of the cargo handling operation in the high lift state.
[0010]
In the present invention, it is preferable to mount the sensor alongside the mast guide roller on the mounting plate for the mast guide roller fixed to the mast from the viewpoint of simplifying the structure and ensuring the detection of the rack. In order to protect the sensor, it is preferable to provide a sensor cover that covers the sensor. Furthermore, it is preferable to use an ultrasonic sensor that is not easily affected by dust or the like.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a plan view of a mast guide roller portion of a forklift according to the present invention, FIG. 2 is a front view thereof, and FIG. 3 is a side view thereof. In the figure, 2 is a mast, 3 is a mast guide roller, and these are provided on the forklift in the manner shown in FIG. A mounting plate 8 is fixed to the mast 2 by a fixing member 9 such as a bolt, and a mast guide roller 3 is mounted on the mounting plate 8 so as to be rotatable about a shaft 16 and a sensor 12 is mounted on the mast guide. It is mounted side by side with the roller 3.
[0012]
A sensor cover 10 covers the sensor 12 and is fixed to the mounting plate 8 by a fixing member 11 such as a bolt. The sensor 12 is an ultrasonic sensor, and is attached to the base 15 of the mounting plate 8 by a bracket 14 as shown in FIG. 4 and 5 are racks, and 13 is a reinforcing frame of the mounting plate 8.
[0013]
In the above configuration, when the forklift is in the path of the rack, the racks 4 and 5 exist in the vicinity of the mast guide roller 3 as shown in FIGS. Therefore, the ultrasonic beam B emitted from the sensor 12 is reflected by the racks 4 and 5 and received by the sensor 12, and the sensor 12 detects that the racks 4 and 5 are in the vicinity of the mast guide roller 3.
[0014]
When the sensor 12 detects the racks 4 and 5, the detection signal is sent to a control unit (not shown), and the control unit performs control so as to allow the mast 2 to rise to an elevated height. Accordingly, by lifting the mast 2 to the uplift position, a cargo handling operation is performed in which the luggage is taken out from the shelf at the high position of the rack and the luggage is stored in the shelf.
[0015]
On the other hand, when the forklift is outside the path of the rack, since the racks 4 and 5 do not exist in the vicinity of the mast guide roller 3, the sensor 12 does not receive the reflected wave of the ultrasonic beam and the rack is not detected. In this case, the control unit performs control so as to prohibit the mast 2 from rising to a higher elevation. As a result, the mast 2 cannot be raised to the elevated position even if the operation is performed outside the rack passage.
[0016]
In this way, the mast 2 is allowed to rise to a higher height only when the forklift is in the passage, and when the forklift is outside the passage, the mast 2 is prevented from being raised to a higher height. Stability can be maintained, and dangers such as rollover can be avoided. Therefore, it is not necessary to limit the load when carrying the cargo handling work at a high lift in the passage, and the degree of freedom of work can be increased.
[0017]
When the forklift is outside the aisle, when the driver performs an operation to raise the mast to the elevated position without knowing it, an indication that raising to the elevated height is prohibited is displayed on the driver's seat display section. May be displayed. Or you may make it alert | report with an alarm sound or an audio | voice instead of this.
[0018]
Further, even if the elevation to the high lift position is prohibited, the rise to the middle lift height or the low lift height may be allowed if necessary. Furthermore, a means such as a release switch for canceling the prohibition of mast elevation may be provided in the case where it is necessary to raise the mast exceptionally outside the passage.
[0019]
In the embodiment described above, since the sensor 12 is mounted on the mounting plate 8 of the mast guide roller 3 along with the mast guide roller 3, it is not necessary to prepare a separate member for mounting the sensor 12, and the structure is simple. This can reduce costs. Further, since the sensor 12 is disposed in proximity to the mast guide roller 3, the racks 4 and 5 can be reliably detected.
[0020]
Moreover, in the said embodiment, since the sensor cover 10 which covers the sensor 12 is provided, the sensor 12 can be protected from a fallen object, dust, etc., and damage and deterioration can be prevented.
[0021]
Further, in the above embodiment, since an ultrasonic sensor is used as the sensor 12, it is possible to avoid malfunction due to clouding of the lens even in a dusty place as compared with the case where a photoelectric sensor is used. , Improve reliability. However, the sensor of the present invention is not limited to an ultrasonic sensor. A photoelectric sensor may be used as long as it is not used in a bad atmosphere such as dust, and other magnetic sensors, limit switches, etc. may be used. Is also possible.
[0022]
【The invention's effect】
According to the present invention, the stability of the vehicle body is ensured regardless of the inside or outside of the rack by providing a rack detection sensor and allowing the mast to rise to a higher height only when the sensor detects the rack. Therefore, there is no load limitation in the work in the rack passage, and the degree of freedom of the cargo handling work can be increased.
[Brief description of the drawings]
FIG. 1 is a plan view of a mast guide roller portion of a forklift according to the present invention.
FIG. 2 is a front view of the same.
FIG. 3 is a side view of the same.
FIG. 4 is a diagram illustrating a state in which a forklift performs a cargo handling operation in a warehouse.
FIG. 5 is a diagram showing a state in which a forklift is traveling in a rack passage.
[Explanation of symbols]
1 forklift 2 mast 3 mast guide roller 4 rack 5 rack 6 passage 8 mounting plate 10 sensor cover 12 sensor

Claims (4)

A forklift that lifts and lowers the mast in the path of the rack and performs a cargo handling work, wherein a mast guide roller that contacts the rack in the path and guides the running of the forklift is provided on the side of the mast. A sensor for detecting a rack existing in the vicinity of the mast guide roller in the passage is provided, and when the sensor detects the rack, the mast is allowed to rise to a higher height, and the sensor detects the rack. A forklift characterized by prohibiting the mast from rising to a higher height if not. The forklift according to claim 1, wherein a sensor is attached to a mounting plate for a mast guide roller fixed to the mast along with the mast guide roller. The forklift according to claim 2, further comprising a sensor cover that covers the sensor. The forklift according to claim 1, 2 or 3, wherein the sensor is an ultrasonic sensor.

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