JPH0729119Y2 - Automated guided vehicle - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application The present invention relates to a low-lift transport vehicle that performs unmanned operation while detecting an obstacle in front of the traveling direction.

B. Outline of the Invention In the automated guided vehicle of the present invention, the loading fork is connected to the main body frame provided with the drive steering wheel so as to be able to move up and down.
This fork is provided with a driven wheel that is always in contact with the floor surface to roll even when the fork is moved up and down, and the drive steering is set so as to travel along a guideway formed on the floor surface. By providing an obstacle sensor capable of detecting an obstacle in front of the traveling direction with a control device for controlling the operation of the wheels, this automatic guided vehicle automatically travels along the guideway and conveys an object. Is carried by the fork while being floated and held, and when an obstacle sensor detects an obstacle ahead in the traveling direction, control such as stop is performed, and it is safe and efficient and unmanned without damaging the conveyed object. Realize transportation.

C. Conventional technology Forklifts have been widely used as cargo-handling vehicles, and in recent years, unmanned forklift trucks that perform cargo-handling work unmanned have also been developed.

On the other hand, a so-called low-lift type transfer vehicle, which is not as versatile as a forklift as a cargo handling vehicle, but is suitable for handling a pallet or the like on the floor level has been developed. This is a loading fork with a limited lift of about 100 to 200 mm, and a driven wheel that is attached to the lower side of the tip of this fork via a vertical position adjusting mechanism such as a jack and is always in contact with the floor and rolls. In addition, a pallet or the like on the floor level is slightly lifted with a fork and conveyed on the floor surface as it is.

D. Problems to be Solved by the Invention A forklift has a complicated structure such as a mast that raises and lowers the fork and a tilt mechanism that tilts the mast, and the fork makes complicated movements during cargo handling work. Therefore, the forklift is generally expensive, and a complicated control device is required to unmanned the forklift, so that the unmanned forklift is very expensive to manufacture. On the other hand, a low-lift type transport vehicle does not require a mast for raising and lowering a fork, which is required in a forklift, and its tilt mechanism, and because of its simple structure it can be downsized and can be manufactured at low cost. Although it has advantages, conventionally, an unmanned version of this low lift type carrier has not been developed.

Particularly in this unmanned operation, there is a problem of how to realize a safe and efficient transport that prevents collision with an obstacle in front of the traveling direction and does not damage the transport. there were.

E. Means for Solving the Problems An automatic guided vehicle according to the present invention comprises a main body frame, driving steerable wheels mounted on the main body frame for driving rotation and steering operation, and a loading unit that is vertically movable to the main body frame. Fork, a driven wheel that is rotatably connected to the fork and rolls on the floor surface, and is provided between the driven wheel and the fork, and the driven wheel is always in contact with the floor surface. Adjusting mechanism for adjusting the distance between the driven wheel and the fork according to the ascending / descending amount of the fork, and controlling the operation of the drive steering wheel so that the fork can travel along a guideway formed on the floor surface. In a low-lift type automatic guided vehicle equipped with a control device for controlling a vehicle, an obstacle sensor for detecting an obstacle in front of the traveling direction and sending a signal to the control device is provided on the main body frame via an arm. It is an feature.

F. Action The drive steered wheels provided on the main body frame operate while being controlled by the control device for the drive steered wheels, and the automatic guided vehicle travels along the taxiway formed on the floor surface. Further, in this automatic guided vehicle, a transported object located in the middle of the guideway is pulled up by a loading fork connected to the main body frame, transported while holding it, and finally placed at a place where it should be transported. During the raising and lowering of the conveyed object and the traveling of the conveyed object, the driven wheel provided on the fork is always in contact with the floor surface by the adjusting mechanism or is in a state of rolling while contacting the floor surface, and the fork is always supported on the floor surface. ing. Further, when there is an obstacle ahead in the traveling direction during traveling, an obstacle sensor provided on the main body frame via an arm detects the obstacle and sends a signal to the control device to perform necessary control.

G. Embodiment Hereinafter, an embodiment of the present invention will be specifically described with reference to the drawings.

FIG. 1 is a perspective view showing the inside of a low lift type automatic guided vehicle according to an embodiment of the present invention with a part thereof seen through, and FIG. 2 is a side view showing the lift mechanism of the fork. In this example, the left side in FIG. 2 will be described below as the front of the automatic guided vehicle.

This low-lift type automated guided vehicle 10 has a fork 12 for loading mounted on a rear portion of a main body frame 11 so as to be vertically movable. The fork 12 is composed of two fork parts 13 extending horizontally rearward for carrying a load, and a mounting part 14 which is vertically erected at the front end part of the fork part 13, as shown in FIG. Body frame by mounting section 14 as shown
It is linked to 11. That is, the mounting portion 14 of the fork 12
A pair of left and right support links 15 pivotally attached to the upper portion of the main body frame 11 are pivotally attached to the upper part of the main frame 11, and a pair of left and right drive links 17 pivotally attached to a bracket 16 protruding from the lower surface of the main body frame 11. The fork 12 is pivotally attached to the lower portion of the fork 12 by a pin 18, and the fork 12 can be moved up and down on the main body frame 11 by a four-joint link mechanism constituted by this.

A pair of left and right fork lifting hydraulic cylinders 19 are vertically oriented between the support link 15 and the drive link 17, and the cylinder and the rod mount the main body frame 11 and the fork 12, respectively. The brackets 20 and 21 are provided so as to project from the portion 14, respectively. Therefore, when the hydraulic cylinder 19 is extended and driven, the fork 12 moves up with respect to the main body frame 11, while when the hydraulic cylinder 19 is shortened, the fork 12 moves down with respect to the main body frame 11 as in the state of FIG. Here, the forks 12 are kept parallel to each other at their ascending ends and descending ends by the action of the aforementioned link mechanism.

On the other hand, a rear wheel 22 as a driven wheel is provided on the lower surface of the front end (rear end) of the fork portion 13. These rear wheels
Reference numeral 22 denotes a driven wheel that is rotatably supported around a horizontal axis that is perpendicular to the longitudinal direction of the fork portion 13.
In each case, a pair is provided. The pair of rear wheels 22 are pivotally supported by the connecting plate 23, and the driven link 24 pivotally attached to the connecting plate 23 is pivotally attached to the lower surface of the fork portion 13 by the pin 25, so that the rear wheel 22 is moved. It has been connected to. Further, a pull rod 27 is pivotally attached to the driven link 24 by a pin 26 located below the pin 25,
The other end of the pull rod 27 is pivotally attached to the drive link 17 by a pin 28 located above the pin 18.

Thus, as shown in FIG. 2, when the fork 12 is in the lowered position, the driven link 24 is in a tilted state, and the rear wheel 22 supports the tip of the fork portion 13 in the lowered position. On the other hand, when the fork 12 is lifted to the raised position by the hydraulic cylinder 19, the drive link 17 is rotated counterclockwise as shown by an imaginary line in FIG.
Is pulled, whereby the driven link 4 is rotated clockwise as shown by an imaginary line in FIG. As a result, the distance between the rear wheel 22 and the upper surface of the fork portion 13 increases, and the rear wheel 22 can support the tip portion of the fork portion 13 in the raised position. That is, the driven link 24 constitutes an adjusting mechanism of the fork portion 13 with respect to the rear wheel 22, and the front end of the fork portion 13 can be supported by the rear wheel 22 regardless of whether the fork 12 is in the ascending or descending position. ing.

As shown in FIG. 1, front wheels 29, which are driving steered wheels, are arranged on the main body frame 11. That is, the body frame
A steering shaft 30 is rotatably supported on the vertical shaft 11 and a support base 31 is attached to the lower portion of the steering shaft 30 so as not to be rotatable about the shaft and movable in the axial direction. A front wheel 29 is rotatably supported below the support base 31 about a horizontal axis. Further, a spring support 32 is provided on the steering shaft 30 in a protruding manner, and a compression coil spring 33 is interposed between the spring support 32 and the support base 31 to urge the support base 31 downward. As a result, the front wheels 29 are pressed against the running floor surface.

A traveling drive motor 34 and its drive gear 35 are mounted on the support 31, and the front wheels 29 are rotationally driven in the forward and reverse directions by the operation of the drive motor 34. On the other hand, a gear 36 is fixed to the steering shaft 30, and a drive pinion of a steering motor 37 supported by the main body frame 11 is provided.
38 meshes with this gear 36,
By operating 37, the steering shaft 30 can be rotated via the drive pinion 38 and the gear 36, and the front wheels 29 can be steered.

Auxiliary wheels 39 each having a caster function are attached to the main body frame 11 on both left and right sides of the front wheel 29.

Further, the main body frame 11 is equipped with an electric hydraulic power unit 40 that operates the hydraulic cylinder 19 described above.
Further, the fork 12 is equipped with a battery 41 that drives the hydraulic power unit 40, the drive motor 34, and the steering motor 37 described above, and the weight of the battery 41 reduces the time required to lower the fork 12 when there is no load. I am trying to

Further, a bracket 42 is attached to a support base 31 supporting the front wheel 29 in front of the front wheel 29, and a forward movement sensor 43 is mounted on the bracket 42 at a symmetrical position with respect to the front wheel 29.
Are fixed respectively. On the other hand, rearward travel sensors 44 are fixed to the front end portions (rear end portions) of the two fork portions 13 of the fork 12 located behind the rear wheel 22. These sensors 43 and 44 detect a taxiway laid in advance on the traveling floor surface, and a control device (not shown) that controls the steering motor 37 in accordance with the output signals of these sensors 43 and 44 is a main body frame 11 It is installed in. The first
In the figure, 45 is an operator console panel for operating the control device, 46 is a power key switch, and 47 is a mode changeover switch.

Various sensors such as an optical type, a magnetic type, and an electromagnetic type can be used for the sensors 43 and 44 in relation to the taxiway laid on the running floor. For example, a pickup coil is used as each of the sensors 43 and 44, and an electric wire that is buried under the running floor and allows a low-frequency current to flow is used as a guideway, and the sensors 43 and 44 are positioned in the magnetic field formed by this current. Therefore, the method of utilizing the induced voltage induced therein is preferably used.

That is, as shown in FIG. 3, when a low-frequency current is passed through the electric wire 50 buried in the taxiway 49 formed on the running floor 48,
A magnetic field 51 is formed concentrically with the outer periphery of the electric wire 50.
If the pickup coils, which are the sensors 43 and 44, are positioned in this magnetic field 51, an induced voltage is generated there. If the electric wire 50 is present in the center of the left and right sensors 43 and 44, the same induced voltage is generated in the left and right sensors 43 and 44, but if they are deviated, a potential difference occurs in the left and right sensors 43 and 44. Therefore, the steering motor 37 is operated in accordance with this potential difference, and the front wheels 29
When the vehicle is steered, the transport vehicle 10 can travel unmanned along the taxiway 49.

In this way, the automatic guided vehicle 10 travels on the traveling floor surface 48 along the guideway 49. However, if any obstacle is present in the forward direction of travel during traveling, the transportation work will be seriously hindered. Therefore, the front portion of the main body frame 11 of the automatic guided vehicle 10 is provided with the above-described bracket 42 as a bumper that can absorb the impact caused by contact with an obstacle or the like and can eliminate the obstacle to some extent. On the other hand, when moving in reverse, the tip of the fork 12 moves in advance, but it is difficult to pick up and hold the conveyed object, so the tip of the fork 12 should be provided with the bumper as described above. Can not. For this reason, an obstacle sensor for detecting an obstacle in front of the traveling direction is provided in the automatic guided vehicle 10, particularly when the vehicle is moving backward.

That is, as shown in FIG. 1 and FIG.
A base end portion of an arm 52 that is protruded upward and that is bent rearward of the main body frame 11 is fixedly provided at 11. An obstacle sensor 53 for detecting an obstacle behind the tip of the fork 12 when moving backward is provided at the tip of the arm 52.
A sensor holder 54 to which is attached is provided. For example, in FIG. 2, an example of a region 55 that can be detected by the obstacle sensor 53 of this embodiment is shown by hatching. Also obstacle sensor
53 is connected to the control device (not shown) that controls the operation of the front wheels 29, and when this obstacle sensor 53 detects an obstacle, an output signal is sent to the control device, and the unmanned guided vehicle 10 Necessary measures such as stop, deceleration or alarm are executed.

By the way, in this embodiment, in order to detect an obstacle when moving backward, the obstacle sensor 53 is provided above the rear of the tip of the fork 12.
The arm is placed via the arm 52.In addition to this, the tip part is the main frame so that obstacles can be detected even when moving forward.
11 Another obstacle located above the front of the main body frame 11 or the arm 52 is attached to the main body frame 11, and an obstacle sensor capable of detecting an obstacle in front of the main body frame 11 at the tip portion.
53 may be attached.

H. Effect of the Invention According to the automatic guided vehicle of the present invention, the automated guided vehicle that automatically travels along the guideway formed on the floor surface and transports the transported object while holding it with the fork is located in the forward direction. By providing an obstacle sensor that outputs a signal for detecting an obstacle and executing necessary control such as stopping, the unmanned conveyance can be performed more safely and efficiently, and the collision with the obstacle can be performed. It is possible to prevent the occurrence of damage or the like on the conveyed object.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an automatic guided vehicle according to the present invention in a partially transparent manner, FIG. 2 is a side view showing a fork lift mechanism of this embodiment, and FIG. It is a schematic diagram showing a principle. In the drawing, 11 is a body frame, 12 is a fork, 13 is a fork portion, and 14
Is a mounting portion, 15 is a support link, 16 is a bracket, 17 is a drive link, 19 is a hydraulic cylinder, 22 is a rear wheel (driven wheel), 23 is a connecting plate, 24 is a driven link, 27 is a pull rod, 29 is a front wheel ( Driving steering wheel), 30 is a steering shaft, 34 is a drive motor for traveling, 37 is a steering motor, 41 is a battery, 42 is a bracket, 43 and 44 are sensors, 48 is a traveling floor surface, 4
Reference numeral 9 is a guide path, 50 is an electric wire, 52 is an arm, 53 is an obstacle sensor, and 54 is a sensor holder.

Claims (1)

[Scope of utility model registration request] 1. A main body frame, drive steerable wheels mounted on the main body frame for driving rotation and steering operations, a loading fork connected to the main body frame so as to be movable up and down, and rotatably connected to the fork. A driven wheel that rolls on the floor surface, and the driven wheel that is provided between the driven wheel and the fork, and that follows the lifted amount of the fork so that the driven wheel always contacts the floor surface. Low-lift type unmanned conveyance including an adjusting mechanism that adjusts the distance between the driving wheel and the fork, and a control device that controls the operation of the drive steered wheel so that the drive wheel can travel along a guideway formed on the floor surface. In the vehicle, an unmanned guided vehicle is provided with an obstacle sensor that detects an obstacle in front of the traveling direction and sends a signal to the control device via the arm.