JPH02147600A - Freight tilt correcting device for automatic forklift - Google Patents

Abstract

PURPOSE:To obtain the correcting device for the tilt of a freight on an automatic forklift with which the loading efficiency onto a container, etc. whose height is restricted can be improved by using a tilt detecting means. CONSTITUTION:A control part 52 operates a selector valve 53 for lift and a selector valve 54 for tilt on the basis of the signal inputted into a receiving means 51 and controls the height of a fork 5 and controls the tilt in the longitudinal direction of the fork 5. A freight 10 is transported to a prescribed position, and the fork 5 is inserted under the fright 10 by the advance of an automatic forklift 1. Then, loading operation is carried out, confirming the lift state of the freight 10 by a transmission means 40 and a receiving means 51. At first, the fork 5 is raised by the elevation of a lift cylinder 6, and then the front part of the fork 5 is deflected, and the front side of the freight 10 is grounded onto the ground 11. In this state, only the rear side of the freight 10 is lifted up from the ground 11, and when the lift quantity becomes equal to a set value, the rise of the lift cylinder 6 is suspended. When the rise of the lift cylinder 6 is completed, it is judged if the lift quantity is equal to the prescribed value or not.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an automatic forklift that automatically performs cargo handling, and particularly to correction of the tilt of a load in an automatic forklift that can perform cargo handling with the cargo held horizontally. Regarding equipment.

[Conventional technology]

As prior art related to the present invention, for example, JP-A-57
-170397 and JP-A-59-82299 are known. The former discloses a method of controlling the horizontal portion of the fork to be horizontal with respect to the vehicle body according to the load of the fork.

The latter is equipped with a tilt detection sensor on the fork that detects the inner wall of the hole in the pallet, and when the fork is inserted into or removed from the hole in the pallet, the posture of the fork is controlled so that it does not hit the hole in the pallet, thereby improving the safety of cargo handling operations. Discloses a device for improving sexual performance.

[Problem to be solved by the invention]

By the way, when loading cargo into an international standard marine container using an automatic forklift, it is necessary to allow for a dead space between the cargo and the ceiling wall of the container due to the longitudinal inclination of the cargo. In other words, it is necessary to secure extra space in the height direction for the slope of the cargo. Therefore, the height of the cargo is limited by the amount of dead space, resulting in a problem that the loading efficiency (load storage capacity) into the container or the like is reduced.

In order to eliminate the occurrence of tilting of the load in the longitudinal direction, it is necessary to keep the fork of the forklift horizontal, but this fork has a cantilever structure, and the weight of the load,
The amount of deflection varies depending on the position of the center of gravity, and it is difficult to handle the load while ensuring it is horizontal.In other words, with conventional equipment, the horizontal posture of the fork can be controlled by controlling the angle of the mast that supports the fork. Because of this, it is not possible to accurately detect the amount of deflection of the fork itself.
The cargo is handled in a forward or backward leaning position, which leads to a reduction in loading efficiency as described above.

Another option is to install a sensor on the fork to detect the distance between the underside of the fork and the floor to keep the fork parallel to the floor, but temporary pallets normally used for cargo handling operations do not have floorboards. In many cases, it is not possible to deal with such cases.

The present invention focuses on the above-mentioned problem, and makes it possible to reliably correct the load placed on the fork to a horizontal state regardless of the deflection of the fork, thereby improving the efficiency of loading onto containers etc. with height restrictions. The purpose of the present invention is to provide a load tilt correction device for an automatic forklift truck that can be used in an automatic forklift truck.

[Means to solve the problem]

The device for correcting the tilt of a load in an automatic forklift according to the present invention in accordance with this object includes a tilt detection means for detecting the tilt of the load placed on the fork of the automatic forklift on the ground side, and a signal from the tilt detection means for detecting the tilt of the load placed on the fork of the automatic forklift. A transmitting means for transmitting data to an automatic forklift is provided, and the automatic forklift is provided with an inclination correcting means for receiving a signal from the transmitting means and correcting the inclination of the load horizontally based on the signal.

[Effect]

In the load tilt correction device for an automatic forklift configured in this way, the degree to which the load itself is tilted is detected by the first-round detection means provided on the ground side. The signal detected by the inclination detection means is transmitted from the transmission means provided on the ground side to the automatic forklift. The automatic forklift receives the signal from the transmitting means and controls the fork so that the load is leveled by the tilt correcting means.

In this way, the present invention detects the inclination of the load itself and controls the fork until the load is actually horizontal, so there is no need to consider the deflection of the fork, and it is possible to ensure that the load is level. Cargo handling becomes possible.

〔Example〕

Below, at in the automatic forklift according to the present invention
A preferred embodiment of the fz tilt correction device will be described with reference to the drawings.

First Embodiment FIGS. 1 to 8 show a first embodiment of the present invention. In FIG. 3, 1 indicates an automatic forklift. There is a mast 3 in front of the front wheels of the automatic forklift 1.
A pair of forks 5 are supported on the mast 3 via a plate 4. The plate 4 is suspended by a chain 9 supported by a rod 6a of two lift cylinders (path shown), and the fork 5 is moved up and down by the expansion and contraction of the rod 6a of the lift cylinder. The mast 3 is connected to the vehicle body 8 via the tilt cylinder 7.
As the tilt cylinder 7 expands and contracts, the mast 3 moves forward (around) or behind (around) the vehicle body 3.

1 and 2 show a state in which a load 10 is placed on the fork 5. In this case, the cargo 10 is stacked in three tiers. On the flat ground 11 side where the automatic forklift 1 is stopped, an inclination detection means 12 for detecting the inclination of the load 10 placed on the fork 5 of the automatic forklift 1 in the front-rear direction is provided. The inclination detection means 12 is located between the left fork 5 and the right fork 5, and most of it is buried underground. The tilt detection means 12 includes a front detection section 20 and a rear detection section 30. The front side detection unit 20 detects the ground 1 on the front side of the cargo 10.
1 to the lower surface of the cargo 1O, and the rear side detection unit 30 detects the lifting height from the ground 1 on the rear side of the cargo 1O.
1 to the bottom surface of the cargo 10 is detected.

4 and 5 show the front detection section 20. FIG.

The front detection section 20 includes a detection rod 21, a holding case 22,
Spring 23, detection dowel 24, proximity sensor 25.26.27
It consists of The detection iron 21 has a top portion 21a formed in the shape of a truncated quadrangular pyramid, and a lower portion 21b formed in the shape of a rod. The top portion 21a and the lower portion 21b are slidably held in a concave holding case 22 fixed to the ground side. A spring 23 that pushes up the detection rod 21 is inserted through the lower part 21b of the detection rod 21, so that the top part 21a comes into contact with the lower surface of the cargo 10. Further, in the lower part 21b of the detection rod 21,
A stopper portion 21c is provided to prevent the top portion 21a from protruding more than necessary from the ground 11.

A detection rod 24 is attached below the stopper portion 21c of the detection rod 21. On the outer periphery of the detection dowel 24,
Proximity sensors 25, 26, and 27 are provided, and these are turned on and emit a signal when the distance from the detection sensor 24 reaches a certain value.

The proximity sensors 25, 26, and 27 are arranged at predetermined intervals in the vertical direction, and the proximity sensor 25 located at the top is for detecting the lifting end, and the proximity sensor 26 located below it is for detecting the optimum lifting height. It is for detection. Furthermore, the proximity sensor 27 located below is used for detecting the lower end.

Although the front detecting section 20 has the above-described configuration, the rear detecting section 30 also has a structure similar to the front detecting section 20, so a description thereof will be omitted.

A transmitting means 40 for transmitting a signal from the inclination detecting means 12 to the automatic forklift 1 is provided on the ground 11 side. That is, each proximity sensor of the front side detection part 20 and the rear side detection part 30 of the inclination detection means 12 is connected to the transmission means 40, and the lift height of the front side and the rear side on the lower surface of the cargo 10 is determined via the transmission means 40. In this embodiment, the transmitting means 40 is constituted by an optical communication device, but is not limited to this, for example, a wireless device, for guiding the automatic forklift. It may be configured by other means, such as a device using a guide wire.

The automatic forklift 1 is provided with a tilt correction means 50 that receives a signal from the transmission means 40 and corrects the tilt of the load 10 horizontally based on this signal. (As shown in FIG. 7, the correction means 50 includes a receiving means 51,
It is composed of a control section 52, a lift switching valve 53, and a tilt switching valve 54.

As shown in FIG. 1, the receiving means 51 is attached to the side surface of the vehicle body 8 of the automatic forklift 1 and is located between the front wheels 18 and the rear wheels 19. The receiving means 51 receives the optical signal from the transmitting means 40, and the transmitting means 40
It is also composed of optical communication equipment.

That is, in this embodiment, from the transmitting means 40 to the receiving means 5
Signal input to 1 is performed without contact. Control unit 52
operates the lift switching valve 53 and the tilt switching valve 54 based on the signal input to the receiving means 51 to control the height of the fork 5 and the inclination of the fork 5 in the front-rear direction. It looks like this.

The tilt switching valve 54 is connected to a hydraulic pump 56 that is rotationally driven by a morph 55, as shown in FIG. A relief valve 57 is connected to the discharge side of the hydraulic pump 56 to adjust the pressure of oil fed under pressure to the tilt cylinder 7. The lift cylinder 6 is also connected to the discharge side of the hydraulic pump 56 via a lift switching valve 53 having a configuration similar to the tilt switching valve 54.

Next, the operation of the first embodiment will be explained using the flowchart of FIG. 8.

The mass, product [10] is conveyed to a predetermined position by a cliff means such as a conveyor or a forklift (not shown). Thereafter, as the automatic forklift 1 moves forward, the fork 5 is inserted below the stack [10], and in this state, the automatic forklift 1 temporarily stops.

Next, the transmitting means 40 and the receiving means 51 transmit the cargo 1.
First, as shown in step 61, when the fork 5 is raised by raising the lift cylinder 6, the front part of the fork 5 is deflected, and the front side of the cargo 10 is lowered to the ground 11. remains in contact with. That is, in this state, only the rear side (the side facing the forklift) of the load 1O is lifted from the ground 11, and the lifting of the lift cylinder 6 is stopped when the lifting height reaches the set value.

The amount of lift is detected by the proximity sensor 25 detecting the detection dog 24.

When the lifting of the lift cylinder 6 is completed, the process proceeds to step 62, where it is determined whether the lift amount is a predetermined value. In this case, if the lift amount exceeds the predetermined value, the process proceeds to step 63, where the rod of the lift cylinder 6 is contracted and the fork 5 is slightly lowered. Conversely, if the lifting height is less than the predetermined value, the process proceeds to step 64, where the rod of the lift cylinder 6 is raised, and the fork 5 is raised slightly.

If it is determined in step 62 that the amount of lift of the fork 5 is the predetermined value, the process proceeds to step 65, where the tilt cylinder 7 performs a tilt up. That is, the mast 3 is tilted backward by the tilt cylinder 7, and the tip of the fork 5 is moved upward. When the tilt-up is performed, the front wheels 18 of the automatic forklift 1 gradually bend due to the weight of the cargo 10, and the lifting height of the front side of the cargo 10 reaches the set value. The amount of lift is detected by the proximity sensor of the rear detection section 30 detecting the detection dog. In this state, the front wheel 1 due to the change in the center of gravity
Due to the elastic deformation of the load 8, the lifting height of the rear side of the load 10 described above decreases.

When the tilt-up is completed, the process proceeds to step 66, where it is determined whether the lift amount is a predetermined value. In this case, if the lift amount exceeds the predetermined value, the process proceeds to step 67, where the tip of the fork 5 is slightly lowered by the operation of the tilt cylinder 7. Conversely, if the lift amount is less than the predetermined value, the process proceeds to step 68, and the tilt cylinder 7
As a result of this operation, the tip of the fork 5 is slightly lifted.

In this state, the cargo 10 is tilted backwards, so proceed to step 69, perform further lift amplification, and confirm again with the proximity sensor that the lifting height on the rear side of the cargo IO has reached the set value. At this point, the final lift amplifier is completed. Next, the process proceeds to step 70, where the cargo 10 is tilted down until the amount of lift on the front side reaches a set value. If it is determined in step 71 that the lifting height of the front side of the cargo 10 and the lifting height of the rear side of the cargo 10 are the same, then the cargo 10
is now in a horizontal state, and the leveling work is completed. Here, if the amount of lift on the front side and the amount of lift on the rear side of the cargo 10 are not the same, the process returns to step 61 and the above-described routine is repeated again.

When the leveling work of the cargo 10 by this device is completed, the automatic forklift l automatically travels along the guide line (illustrated path) buried in the traveling road surface and stops at the entrance of the container (illustrated path) to be loaded. . Then, the load rt110 is aligned with the container by the lift cylinder 6, and the load 10 is carried into the container by the advance of the automatic forklift 1. In this case, since the cargo 10 is in a horizontal state, there is no need to provide a dead space between the cargo and the ceiling wall of the container as in the conventional case when the cargo is carried in at an angle. In other words, the cargo height can be increased by the amount of extra space required.
Loading efficiency into containers can be increased.

Second example FIG. 9 shows a second embodiment of the invention.

The second embodiment differs from the first embodiment only in part of the tilt detection means and tilt correction means, and the other parts are the same as the first embodiment. By assigning reference numerals, the explanation of the corresponding parts will be omitted, and the different parts will be explained.

In the first embodiment, in order to correct the inclination of the load in the longitudinal direction, the inclination detection means was arranged in the longitudinal direction of the automatic forklift l, but in this embodiment, in order to correct the inclination of the load 10 in the left and right direction. , the inclination detection means 12 are arranged in the left-right direction of the automatic forklift (1).

Furthermore, in this embodiment, the side shift control means 80 of the automatic forklift 1 is also used as a method for horizontally correcting the inclination of the load 10 based on the signal from the inclination detection means 12. That is, if the weight of the cargo 10 is biased to one side and the cargo 10 is tilted due to this, the entire pair of forks 5 are moved in the left-right direction by the side shift control means 70, so that the cargo 10 is tilted to one side. It is designed to correct the slope of.

Note that even if a lift cylinder that raises and lowers the left and right forks 5 independently is used, it is possible to correct the horizontal inclination of the cargo 10 based on the signal from the inclination detection means 12.

Furthermore, in each of the above embodiments, a plurality of proximity sensors are used as the inclination detection means, but a configuration may also be adopted in which a differential transformer or the like that continuously detects the amount of lift is used.

C Effects of the Invention] As explained above, when using the load tilt correction device in the automatic forklift according to the present invention, on the ground side,
A tilt detecting means for detecting the tilt of a load placed on the forks of an automatic forklift, and a transmitting means for transmitting a signal from the tilt detecting means to the automatic forklift are provided, and the automatic forklift receives the signal from the transmitting means and transmits the signal. Since the inclination correcting means for correcting the inclination of the cargo horizontally based on the signal is provided, it becomes possible to load the cargo into a container or the like in a horizontal state regardless of the deflection of the fork.

As a result, there is no need to provide extra space between the cargo and the ceiling wall of the container in case the cargo is brought in at an angle, and the height of the cargo can be increased accordingly. . Therefore, the efficiency of loading onto containers etc. can be improved, and logistics costs can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a side view showing cargo handling using a load tilt correction device in an automatic forklift according to a first embodiment of the present invention, FIG. 2 is a plan view of FIG. 1, and FIG. FIG. 4 is a sectional view of the inclination detection means in FIG. 1, FIG. 5 is a plan view of FIG. 4, FIG. 6 is a control system diagram of the device in FIG. 1, and FIG. 7 is a perspective view of an automatic forklift. FIG. 8 is a flowchart showing the flow of control in the device shown in FIG. 1; FIG. 9 is a plan view of a load tilt correction device for an automatic forklift according to a second embodiment of the present invention. , is. l...Automatic forklift 5...Fork 6...Lift cylinder 7...Tilt cylinder lO...Load 12... Tilt detection means 40... Transmission means 50... Tilt correction means 51... Receiving means 52... Control section 53... Lift switching Valve 54... Cutting pulp for tilting Figure 3

Claims (1)

[Claims] 1. Provided on the ground side with a tilt detection means for detecting the tilt of a load placed on the fork of an automatic forklift, and a transmission means for transmitting a signal from the tilt detection means to the automatic forklift, and the automatic forklift has: A load tilt correction device for an automatic forklift, characterized in that the load tilt correction device for an automatic forklift is provided with tilt correction means for receiving a signal from the transmitting means and correcting the tilt of the load horizontally based on the signal.