JP2890350B2 - Overhead traveling car - Google Patents

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 that moves a lifting table up and down to transfer a conveyed article to and from the ground, and holds the conveyed article to travel.

[0002]

2. Description of the Related Art An overhead traveling vehicle is used which travels along a rail suspended from a ceiling and transfers a conveyed product to and from a station on the ground. The overhead traveling vehicle stops just above the station on the ground, lowers the elevator, and transfers the articles by the article holding mechanism provided on the elevator.

[0003]

When an overhead traveling vehicle handles a plurality of types of conveyed products, the level at which the elevating platform stops lowering when receiving the conveyed products may be different because the sizes of the conveyed products are different. In such a case, the type of the conveyed object placed on the ground station is transmitted to the overhead traveling vehicle, and the control device of the overhead traveling vehicle selectively determines the level at which the elevator is stopped according to the type of the conveyed object. Was. According to such a method, the control of the overhead traveling vehicle becomes complicated, and it takes time and effort to rewrite data.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide an overhead traveling vehicle capable of handling a plurality of types of conveyed articles without a complicated control structure.

[0005]

In order to achieve the above-mentioned object, the present invention provides a method in which a pair of chucking claws reach a chucking level at which a gripped portion on an upper portion of a conveyed object can be gripped while the elevator is lowered. A grasped portion detection means arranged to detect a grasped portion, and a descent of the elevating platform is stopped when the grasped portion detection means detects the grasped portion. An overhead traveling vehicle is provided with a lifting drive means for lowering the lifting platform to the king level.

[0006]

The present invention has the above-described structure, and has the following effects.

In the overhead traveling vehicle according to the present invention, when the overhead traveling vehicle stops traveling and lowers the elevating platform, if the gripped portion detecting means does not detect the gripped portion, the lowest chucked transported material among the handled transported objects. Lower the platform to the king level. Thereby, chucking of the conveyed object having the lowest chucking level can be performed. When the gripped portion detecting means detects the gripped portion, the lowering of the elevator is stopped. Since the chucking claw has reached the chucking level at which the gripper at the upper part of the conveyed object can be gripped when the gripper detection means detects the gripper while the lift platform is descending, the chucking at this level is the lowest. It is possible to chuck a transported product other than the transported product having the king level.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiment shown in the drawings will be described below.

FIG. 1 is a front view showing an elevator unit of an embodiment of an overhead traveling vehicle according to the present invention.

In FIG. 1, an elevator 1 is raised and lowered by lifting and lowering belts 2 and 2 by a lifting mechanism provided on an overhead traveling vehicle (not shown). A pair of chucking claws 3 and 3 are provided on the lower surface of the lift 1 so as to move toward and away from each other. The guides 4, 4 are respectively guided by guide poles 5, 5 erected at a station on the ground, thereby adjusting the horizontal position of the elevator 1.

On the ground station, wafer cassettes 6a or 6b of different sizes, which are to be transported, are placed. Each of the wafer cassettes 6a and 6b is provided with a pair of gripped portions 7a and 7b at an upper portion thereof. Each of the gripped portions 7a, 7b has a size and a shape corresponding to the chucking claws 3, 3, respectively. The wafer cassette 6a is the smallest transported object handled by the overhead traveling vehicle of the present embodiment, and the gripped portion 7a is at the lowest level as compared with the gripped portions of other transported objects.

A light emitting device 8 is mounted on one of the chucking claws 3 and a light receiving device 9 is mounted on the other, so that the light receiving device 9 can receive the optical axis L emitted from the light emitting device 8. It has become. The light receiver 9 is connected to a lifting mechanism of the lifting table 1. The light emitting device 8 and the light receiving device 9 are mounted slightly above the horizontally projecting portions of the chucking claws 3, 3. When the chucking claws 3, 3 are at a height capable of gripping the gripped portion 7, The optical axis L is shielded by the gripped portion 7.

Next, the operation of this embodiment will be described. The overhead traveling vehicle stops right above the station to receive the conveyed product, and then operates the drive mechanism to lower the elevator 1. The lift 1 descends while being guided by the guides 4 and 4 and the guide poles 5 and 5.

At this time, the light emitting device 8 emits the optical axis L, and the light receiving device 9 receives the optical axis L. Also, chucking claws 3,
3 are mutually open. When the small wafer cassette 6a is placed in the station, the optical axis L emitted from the light emitting device 8 is not interrupted, and the elevator 1 descends to the preset lowest level and stops. This level is a level corresponding to the wafer cassette 6a. Then, the chucking claws 3, 3 are closed like 3a, 3a, and the lifting table 1 is raised to hold the wafer cassette 6a.

A large wafer cassette 6b is set in the station.
When is placed, when the elevator 1 is lowered,
Before reaching the preset lowest level, the optical axis L is blocked by the gripped portion 7b. When the elevating mechanism of the elevating platform 1 stops the lowering of the elevating platform 1 when the optical axis L is cut off, the chucking claws 3b, 3b are moved to the wafer cassette 6b.
Is located at a height where the gripped portion 7b can be chucked. When the chucking claws 3, 3 are closed at this position and the elevating platform 1 is raised, the wafer cassette 6b can be held.

As described above, according to the overhead traveling vehicle of this embodiment, it is possible to determine the stop position of the lift platform without requiring a complicated control mechanism, and to cope with conveyed objects of different sizes.

The embodiments of the present invention have been described above.
It is needless to say that the present invention is not limited to the above-described embodiments, and can be appropriately modified and implemented within the scope of the present invention.

[0018]

As described above, according to the overhead traveling vehicle according to the present invention, the stop position of the lift platform can be adjusted so as to correspond to a plurality of types of conveyed objects without a complicated control mechanism. Can be determined.

[Brief description of the drawings]

FIG. 1 is a front view showing an elevator unit of an embodiment of an overhead traveling vehicle according to the present invention.

[Description of Signs] 1 Lifting platform 2, 2 Belt 3, 3 Chucking claw 6a, 6b Wafer cassette 7a, 7b Gripped portion 8 Light emitting device 9 Light receiving device L Optical axis

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B66C 13 / -15/06

Claims (1)

(57) [Claims] 1. A grasped portion detection device arranged to detect a grasped portion when a pair of chucking claws reach a chucking level at which a grasped portion above a conveyed object can be grasped while the lifting platform is lowered. And lifting drive means for stopping the lowering of the elevator when the gripper detection unit detects the gripper, and lowering the elevator to the lowest chucking level of the handling conveyed when not detecting. Overhead traveling car.