JPH0527437Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a forklift truck, and in particular, a load proximity detection method for detecting when a load on the fork is sufficiently close to an object ahead in the direction of travel of the truck. Regarding equipment.

BACKGROUND OF THE INVENTION Forklift trucks are used to transport cargo and perform cargo handling operations. There are two types of forklift trucks: ordinary forklift trucks that are driven by a driver, and unmanned forklift trucks that are driven unmanned by a predetermined guidance system.

When loading cargo into a container sequentially using these forklift trucks, it is desirable to load the front wall of the container, the frontmost cargo, and each cargo in close contact with each other in the front and rear direction without any gaps in order to increase loading efficiency. . However, it is not easy to know with certainty whether the load on the fork has made contact with the front wall of the container or with a previous load. Therefore,
There have been cases where loading work has been carried out with a gap remaining between the front wall of the container and the cargo at the front end, or between each cargo, and the cargo at the rear cannot fit into the container and the work has to be restarted.

Therefore, a forklift truck equipped with a backward detection device as described in Japanese Patent Application Laid-Open No. 61-282298 has been developed. This means that when the forklift truck reaches the unloading position and the load on the fork hits a stationary wall in front (e.g. the front wall of a container) or the load, the entire load is pushed back to the rear relative to the fork. This activates the left and right backward detection positions to stop the forklift truck. According to this detection device, when loading cargo into a container, it becomes possible to load the cargo without gaps in the front and rear directions.

Problems that the invention aims to solve: However, when loading cargo into a container, etc., even if the cargo on the fork hits the cargo in front or the front wall, it may not move backward, and the backward detection position does not operate. However, there was a problem that cargo could not be loaded properly. For example, in a child forklift truck of a parent and child forklift truck, the driving force of the drive wheels is smaller than that of a normal forklift truck, and its own weight is also smaller.
When a load comes into contact with a front wall or the like, the drive wheels may stop rotating or slip, causing the forklift truck itself to no longer move forward, and the load may not slide on the forks.

In addition, there are cases in which the load has low strength relative to its weight, and cannot be pressed against the load in front of the load so strongly that it slides on the fork.

In this way, even if the cargo does not slide on the fork and collision with the cargo in front cannot be detected depending on the backward detection position, the cargo can be loaded into a container etc. by touching each other or bringing them sufficiently close together. This was done with the aim of obtaining a cargo proximity detection device that makes it possible to do this.

Means for solving the problem To this end, the cargo proximity detection device according to the present invention has the following features:
(a) A first sensor installed at the tip of the fork to detect the distance to the object in front; (b) A second sensor installed at the proximal end of the fork to detect the distance to the cargo on the fork. (c) cargo dimension setting means for setting the longitudinal dimension of the cargo; and (d) the detection value X of the first sensor, the setting value L of the cargo dimension setting means, the detection value Y of the second sensor, and the first When the relationship α≧X+W−(L+Y) is established between the distance W in the front-rear direction between the sensor and the second sensor and the preset tolerance α, the cargo on the fork will strike the front object within the tolerance. and determining means for determining that the distance is close to each other.

Functions and Effects According to the detection device configured as described above, since the distance W between the first sensor and the second sensor is set in advance, the operator can calculate the longitudinal dimension L of the load to be loaded onto the fork. When set by the dimension setting means, the determination means determines whether or not α≧X+W−(L+Y) is established between these and the detection value X of the first sensor and the detection value Y of the second sensor. It is determined whether the upper cargo has approached the front wall or a front object such as cargo to a distance within tolerance. If this determination result is affirmative, the cargo can be loaded with almost no gaps in the front-rear direction if unloading is performed by the driver's operation or automatically.
At this time, even if the load is not loaded at the correct position on the fork, or if the load shifts position while the forklift truck is running, the second sensor detects the loading position of the load. By doing so, the distance between the cargo and the object in front is detected and it is determined whether the two are close, allowing the driver to more accurately determine whether or not to unload the cargo. can be judged. Even if the dimensions of the cargo in the front and back directions are different,
Even if the loading position of the cargo on the fork is not constant, the cargo can be loaded at appropriate intervals within the same tolerance range. Therefore, it is possible to reliably load a predetermined amount as planned, and it is possible to improve volumetric efficiency.

Further, a plurality of first sensors are installed in the width direction of the forklift truck, a second sensor is provided corresponding to each first sensor, and the determination means is used to determine each of the plurality of sets of the first sensor and the second sensor. In that case, it becomes possible to detect the degree of parallelism between the front surface of the cargo and the rear surface of the object in front.
It becomes possible to more accurately determine the state of proximity to the object in front.

Embodiment Next, an embodiment of the present invention will be described based on the drawings.

FIG. 1 is a diagram showing a case where the load proximity detection device of the present invention is installed in a parent-child forklift truck (hereinafter abbreviated as parent-child forklift).
In the parent and child forklift, a parent forklift 10 and a child forklift 11 are separable, and the child forklift 11 is remotely controlled by the parent forklift 10 to carry cargo into a container.

In the figure, 12 is the body of the parent forklift 10, with the front wheels serving as driving wheels 14 and the rear wheels serving as steering wheels 16. A balance weight 18 is provided at the rear of the vehicle body 12, and a head guard 20 is provided above. At the front of the vehicle body 12, cargo handling devices such as an outer mast 22, an inner mast (not shown), and a lift bracket are provided. The inner mast is guided in the vertical direction by the outer mast 22 via rollers, and this inner mast further guides the lift bracket. A finger bar 26 is attached to the lift bracket via a side shift attachment 24.
is attached to the finger bar 26, and the child forklift 11 is detachably attached to the finger bar 26. When the inner mast is raised by the operation of the lift cylinder, the lift bracket, finger bar 26 and child forklift 11 are raised integrally by the chain. The lower end of the outer mast 22 is attached to the vehicle body 12 so as to be rotatable about one axis, and the operation of the tilt cylinder 30 causes the cargo handling equipment including the outer mast 22 to be tilted forward or backward. Further, by operation of a side shift cylinder (not shown), the finger bar 26 and the child forklift 11 are side-shifted in the left-right direction of the vehicle body 12 with respect to the lift bracket.

The child forklift 11 is usually called a low lift, and is described in, for example, Japanese Utility Model Application No. 60-90297. The child forklift 11 includes a main body portion 36 consisting of a front portion 32 and a rear portion 34, a backrest 38, and a fork 40 for loading cargo A. Child forklift 11 fork 40
is raised and lowered by a lifting mechanism 42 provided between the backrest 38 and the front part 32 of the main body part 36. The elevating mechanism 42 is composed of links, hydraulic cylinders, and the like. Rear part 3 of child forklift 11
A drive wheel 44 that also serves as a steering wheel is attached to the fork 4, and an elevating wheel 46 is attached to the tip of each fork 40. The lifting wheel 46 is a fork 40
It is designed so that it can be moved in and out of the fork 40 as it goes up and down.

Each mechanism of the child forklift 11 is operated by oil pumped from the parent forklift 10 side. As is clear from Figure 1,
A hose 48 that supplies oil to each mechanical part of the child forklift 11 is connected between the parent forklift 10 and the child forklift 11. The hose 48 is adapted to be wound up by a hose reel 52 attached to a strut 50 of the parent forklift 10. In this embodiment, six hoses 48 are connected to the rear part 34 of the child forklift 11, and each hose 48 passes over the head guard 20 of the parent forklift 10 and connects to three hose reels 52.
It's like it's being wound up. These mechanisms are operated by a joystick controller of the parent forklift 10, and their speeds are controlled by operating the accelerator of the parent forklift 10.

As shown in FIG. 2, first sensors 54 and 56 are attached to the tips of the forks 40 of the child forklift 11, respectively. The first sensors 54 and 56 use ultrasonic waves to detect objects such as the front wall of a container or an obstacle in front of the child forklift 11 in the traveling direction, and in the illustrated example, the cargo B loaded in the container 60 of the truck 58. and the first sensor 54,
This is to detect the distance to 56.

Also, the back crest 3 of the child forklift 11
Second sensors 62, 64 are attached to both sides of 8 in correspondence with the first sensors 54, 56. The second sensors 62, 64, like the first sensors 54, 56, use ultrasonic waves to detect the backrest 38 and fork 4.
This is to detect the distance from the rear end of the cargo A on the 0.

The main body portion 36 of the child forklift 11 is provided with a computer 66 shown in FIG. An input device 68 is connected to the computer 66 for inputting the dimension L of the cargo A, the allowable error α, and the like. The input device 68 constitutes the cargo size setting means of the present invention. The computer 66 has an I/O port 70, a CPU 72, a ROM 74,
It consists of RAM 76 and a bus 78 connecting them. The ROM 74 stores control programs including the unloading routine shown in the flowchart of FIG. 4, and the distance W between the first sensors 54, 56 and the second sensors 62, 64.
And these L, W, α, the first sensor 54,
56 and the value of the distance X detected by the second sensor 62,
Between the value of distance Y detected by 64, α≧X+W
It is determined whether -(L+Y) holds true.
As a result of the determination, if the above formula holds true, the drive wheels 44 of the child forklift 11 are controlled to stop the movement of the child forklift 11, and the lifting mechanism 42 is caused to unload the load. If the above formula does not hold true, the child forklift 11 is stopped from running, and then an alarm device 80 such as an alarm or alarm lamp is used to notify the operator of the abnormality. That is, in this embodiment, the first sensors 54, 56 and the second sensors 62, 64
and a computer 66 serving as a determining means constitute a cargo proximity detection device.

Next, the operation will be explained.

The child forklift 11 is transported to the truck 58 by the parent forklift 10 with the cargo A loaded on the fork 40. When the child forklift 11 is positioned within the container 60 of the truck 58, the finger bar 26 of the parent forklift 10 is lowered and the child forklift 11
is removed, the backrest 38 is raised, and the elevating wheels 46 are made to protrude below the fork 40, making it possible to travel inside the container 60.

While the child forklift 11 travels within the container 60, the computer 66 executes the unloading routine shown in FIG.

In step S1 (hereinafter simply referred to as S1; the same applies to other steps), it is determined whether the child forklift 11 has collided with a forward object such as a load B or an obstacle. This determination is made based on the fact that the oil pressure of the hydraulic motor that drives the drive wheels 44 has risen above a set value, or that the elevator wheels 46 have stopped rotating even though a forward command has been issued. be able to. If the child forklift 11 is moving forward, the judgment result is NO.
Until the child forklift 11 stops.
S1 is repeated. If the child forklift 11 collides with the object in front, the judgment of S1 becomes YES and S2
is carried out, and the detected value of the distance X between the cargo B and the first sensors 54, 56 is fetched from the first sensors 54, 56 and stored in the RAM 76 of the computer 66. At the same time, the detected value of the distance Y between the cargo A and the second sensors 62, 64 detected by the second sensors 62, 64 is also stored in the RAM 76. These detected values X, Y, the length L of the cargo A input from the input device 68 and the allowable error α,
The first sensor 54, 5 stored in the ROM 74
6 and the distance W between the second sensors 62 and 64 to S3
A determination is made as to whether α≧W+X−(L+Y) holds. And left and right fork 4
If the judgment result is YES at 0,
It is determined that the cargo A on the child forklift 11 is in close contact with the cargo B in a normal state, the child forklift 11 is stopped in S4, and unloading of the cargo A is started in S5. That is, the lifting mechanism 42 is operated, the fork 40 is lowered, and the cargo A is lowered onto the floor of the container 60. In this way, cargo A can be stacked behind cargo B without any gaps.

On the other hand, if the above equation does not hold true for either the left or right side of the forklift 40, the result of the determination in S3 becomes NO, and in S6 the child forklift 11
is stopped, and the alarm device 80 notifies the operator of the abnormality in S7. In this case, it is desirable to provide an alarm device for each of the left and right forks 40. Thereby, the operator can determine which side of the load A collided with the load B or the obstacle, and can either move the child forklift 11 backwards to reload the load, or load the load A at the correct position on the fork 40. You can take measures such as fixing the problem.

Although one embodiment of the present invention has been described above, the determination means may be constructed of an electronic circuit including an arithmetic unit, a comparator, etc. instead of a computer.

In addition, in this embodiment, when the load on the fork comes into contact with the load in front, the determination means is made to make a determination, but the forklift is run while making the determination, and the load in front is The forklift may be stopped when it is determined that the forklift has approached. In this way, the cargo on the fork can be loaded behind the fork with a small gap without coming into contact with the cargo in front.

Furthermore, the cargo proximity detection device of the present invention can be installed not only in parent-child forklifts but also in ordinary manned forklifts and unmanned forklifts. In that case, it is also possible to detect that the cargo has collided with an obstacle or the like and has shifted.

Further, the number of the first sensor and the second sensor is not limited to two sets, but a plurality of sets may be provided, or only one set may be provided.

In addition, various modifications based on the knowledge of those skilled in the art,
The invention can be implemented in improved ways.

[Brief explanation of the drawing]

Fig. 1 is a front view showing a state where a parent-child forklift equipped with a cargo proximity detection device according to an embodiment of the present invention is loading cargo into a container. Fig. 2 is a plan view showing a child forklift of the parent-child forklift. Fig. 3 is a block diagram showing the cargo proximity detection device of this embodiment, and Fig. 4 is a flow chart showing a program for controlling unloading of the device in Fig. 3. 10... parent forklift, 11... child forklift, 40... fork, 54, 56... first sensor, 62, 64... second sensor, 66...
Computer.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A forklift truck is provided with a forklift truck that travels with a load loaded on a front cargo handling device equipped with a fork, and the load on the fork is a forward object in the forward direction of the forklift truck. A cargo proximity detection device detects that the fork approaches the fork to a distance within a tolerance, the first sensor being provided at the tip of the fork and detecting the distance to the forward object, and the proximal end side of the fork. a second sensor provided on the fork for detecting the distance to the load on the fork; a load size setting means for setting the longitudinal dimension of the load; and a detection value X of the first sensor and the load size setting means. The relationship α≧W+X−(L+Y) is established between the set value L, the detected value Y of the second sensor, the distance W in the front-rear direction between the first sensor and the second sensor, and the preset tolerance α. and determining means for determining that the load on the fork has approached the forward object to a distance within the tolerance. (2) a plurality of the first sensors are provided at a distance in the width direction of the forklift truck;
The second sensor is provided corresponding to each of the plurality of first sensors, and the determination means makes the determination regarding each of the plurality of sets of first sensors and second sensors. Detection device according to item 1.