JPH0624684A - Load detection device for overhead traveling vehicle - Google Patents

Abstract

PURPOSE:To more accurately judge whether or not a gripping mechanism of an overhead traveling vehicle is gripping a load. CONSTITUTION:The device is provided with an opening/closing sensor 25 which is turned on when a gripping mechanism is in a closing state and proximity switches 24 which are turned on when a load is engaged with a chucking member of the gripping mechanism. When the proximity switches 24 and the opening/ closing sensor 25 are all turned on, a relay 46 is closed and a signal indicating that the load is being gripped by the gripping mechanism is outputted. Accordingly, an overhead traveling vehicle is prevented from conducting conveying action without a load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an overhead traveling vehicle which is installed in an automated warehouse or the like and travels along a ceiling rail, and more particularly to a device for detecting that the overhead traveling vehicle is holding a load.

[0002]

2. Description of the Related Art Conventionally, as an automatic warehouse, one having an overhead traveling vehicle is known, and the overhead traveling vehicle conveys a bucket by grasping and suspending a bucket containing a silicon wafer or the like. The gripping mechanism provided on the overhead traveling vehicle grips and lifts the bucket at a predetermined position. In this state, the overhead traveling vehicle travels while being guided by rails provided on the ceiling, and conveys the bucket to a predetermined position. Whether the gripping mechanism is gripping the bucket is determined by the open / closed state of the gripping mechanism, that is, it is determined that the gripping mechanism is gripping the bucket when the gripping mechanism is in the closed state.

[0003]

However, according to the configuration in which the presence / absence of a load is determined only by the open / closed state of the gripping mechanism, if the load is gripped even when the gripping mechanism is closed without the load. As a result of the determination, the overhead traveling vehicle executes a predetermined transport operation for the luggage. The present invention has been made for the purpose of providing a luggage detection device capable of more accurately determining whether or not a grasping mechanism is grasping a luggage.

[0004]

A luggage detection device for an overhead traveling vehicle according to the present invention comprises means for detecting a closed state of a gripping mechanism, and means for detecting that a luggage is engaged with the gripping mechanism. The closed state detecting means detects the closed state of the gripping mechanism,
Further, it is characterized in that it is provided with means for judging that the load is gripped by the gripping mechanism only when the engagement detecting means detects the load.

[0005]

The present invention will be described below with reference to illustrated embodiments. FIG. 1 shows an example of the configuration of the overhead traveling vehicle 11. Overhead traveling vehicle 1
The main body 12 of No. 1 travels while being guided by rails 13 provided on the ceiling, and an elevating table 14 is provided below the main body 12. The elevating table 14 is suspended from the main body 12 by four steel belts 15, and the steel belts 15 are raised or lowered by winding or releasing the steel belts 15. Two gripping mechanisms 21 are provided on the lower surface of the lifting table 14. These gripping mechanisms 21 grip and suspend a bucket (luggage) 31 containing, for example, a silicon wafer. The lift table 14 is provided with a motor (not shown) that drives the gripping mechanism 21, a luggage detection circuit (not shown) that determines whether or not the bucket 31 is gripped, and the like.

FIG. 2 shows the bucket 31. The bucket 31 has a box shape, and a pair of flanges 32 that can be engaged with the gripping mechanism 21 of the overhead traveling vehicle 11 are formed at the upper end portion. Each flange 32 is provided with a hole 33 into which the positioning pin 23 (FIG. 3) of the gripping mechanism 21 is fitted.

FIG. 3 shows a state in which the flange 32 of the bucket 31 is placed on the chucking member 22 of the gripping mechanism 21. The chucking member 22 is a flat plate and is fixed to the tip of an arm 29 extending downward from the elevating table 14 (FIG. 1). A flange 32 is provided on the chucking member 22.
The positioning pin 23 fitted in the hole 33 of the
A proximity switch 24 is provided which detects when two are engaged. The output signal of the proximity switch 24, that is, the signal indicating whether or not the flange 32 of the bucket 31 is engaged, is input to the package detection circuit 41 (FIG. 4) described later.
Further, a signal indicating the open / closed state of the chucking member 22 of the gripping mechanism 21 is also input to the luggage detection circuit 41.

FIG. 4 shows a package detection circuit 41, which is connected to a drive circuit 43 of a motor 42 which drives the chucking member 22 to open and close. The drive circuit 43 is connected to the first and second steel belts 15a and 15b of the four steel belts, and a voltage of 15V is applied via the steel belts 15a and 15b. That is, the motor 42 is rotated by the application of this voltage to open / close the chucking member 22.

On the other hand, the luggage detection circuit 41 is connected to the second, third and fourth steel belts 15b, 15c and 15d, and these steel belts 15b, 15c and 15d are connected.
A voltage of 24 V is applied via the. Package detection circuit 41
Has a DC / DC converter 44, a logic circuit 45, and a relay 46. The DC / DC converter 44 is the second
And 2 via the third steel belts 15b, 15c
A voltage of 4V is applied, and this is transformed into 5V and output. The logic circuit 45 is applied with a voltage of 5V and a voltage of 24V by the DC / DC converter 44, and as described later, closes the relay 46 when a predetermined condition is satisfied. The contacts of the relay 46 are connected to the third and fourth steel belts 15d, and when closed, 2
A voltage of 4V is applied.

FIG. 5 shows the structure of the logic circuit 45. The logic circuit 45 detects whether or not the gripping mechanism 21 is gripping the bucket 31. The logic circuit 45 includes four proximity switches 24 provided on the gripping mechanism 21 of the lift 14 (FIG. 1) and the chucking member 2 of the gripping mechanism 21.
The open / close sensor 25 for detecting the open / closed state of No. 2 is connected. The proximity switches 24 and the open / close sensors 25 are connected to the photocouplers 51 to 55, respectively, and when the proximity switches 24 and the open / close sensors 25 are turned on, the corresponding photocouplers 51 to 55 are turned on. . For example, when the open / close sensor 25 is turned on, the photo coupler 55 is turned on. Photo coupler 51-55
A voltage of 24 V is applied to the photodiode.

The photocouplers 51 to 55 are AND gates 5.
6 and the output end of the AND gate 56 is connected to the photocoupler 57. The AND gate 56 outputs an ON signal when all of the photocouplers 51 to 55 are turned on, whereby the photocoupler 57 is turned on. The photodiode of the photo coupler 57 is DC
The voltage of 24V is applied to the phototransistor of the photocoupler 57, which is connected to the / DC converter 44. The photocoupler 57 is connected to the fixed iron core side of the relay 46 and applies a voltage of 24 V to the relay 46 when in the ON state, whereby the relay 46 is closed.

That is, it is detected that the four proximity switches 24 are on and the bucket 31 is engaged with the gripping mechanism 21, and the open / close sensor 25 is on and the gripping mechanism 21 is closed. When it is detected that
The relay 46 is closed. As a result, a signal indicating that the bucket 31 is gripped by the grip mechanism 21 is output to the control unit (not shown) of the overhead traveling vehicle 11. Therefore,
In the control unit of the overhead traveling vehicle 11, the bucket 31 is mounted on the lift base 14
The predetermined carrying operation for the bucket 31 is performed only when it is engaged with, and it is possible to reliably prevent the carrying operation from being performed without a load as in the conventional case.

As described above, in the present embodiment, a signal indicating that the bucket 31 is gripped by the gripping mechanism 21 is transmitted via the four steel belts 15 suspending the lifting table 14 from the main body. It is possible to output to 12, and it is possible to more accurately determine whether or not the gripping mechanism 21 is gripping the bucket 31 without making a large change to the existing overhead traveling vehicle.

The configuration of the logic circuit 45 is merely an example, and various circuit configurations can be adopted. It goes without saying that the luggage carried by the overhead traveling vehicle 11 is not limited to the bucket 31.

[0015]

As described above, according to the present invention, it is possible to more accurately determine whether or not the gripping mechanism is gripping a load, and it is possible to reliably prevent an erroneous conveyance operation.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of an overhead traveling vehicle to which an embodiment of the present invention is applied.

FIG. 2 is a perspective view showing a bucket.

FIG. 3 is a cross-sectional view showing a state in which the flange of the bucket is placed on the chucking member of the gripping mechanism.

FIG. 4 is a circuit diagram showing a schematic configuration of a package detection circuit.

FIG. 5 is a circuit diagram showing a configuration of a logic circuit.

[Explanation of symbols]

 11 Overhead traveling vehicle 21 Grasping mechanism 24 Proximity switch 25 Opening / closing sensor 31 Bucket (luggage) 41 Luggage detection circuit 45 Logic circuit 46 Relay

Claims (1)

[Claims] 1. An overhead traveling vehicle for gripping and transporting a load by a gripping mechanism, said means for detecting a closed state of the gripping mechanism, and means for detecting that the load is engaged with the gripping mechanism. The closed state detection means detects the closed state of the gripping mechanism,
And a means for determining that the luggage is gripped by the gripping mechanism only when the engagement detection means detects the luggage, the luggage detection device for an overhead traveling vehicle.