Movable platform, overhead traveling vehicle system, and method for vertically moving overhead traveling vehicle

A moving carriage that moves an overhead travelling vehicle that has been unloaded to the ground, includes a frame including travelling wheels, elevating mechanisms provided at a plurality of locations on the frame along a longitudinal direction of the frame, a track for an overhead travelling vehicle, the track being supported by the elevating mechanisms so as to be lifted and lowered and being configured to allow the overhead travelling vehicle to be transferred to and from another track, and a synchronizing mechanism that synchronizes the elevating mechanisms to lift and lower the track by the same or substantially the same amount.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a moving carriage for use in an overhead travelling vehicle system.

2. Description of the Related Art

With an overhead travelling vehicle system, an overhead travelling vehicle travels along a travelling track provided in an overhead space. In this respect, in order to load the overhead travelling vehicle onto the travelling track or unload the overhead travelling vehicle from the travelling track to the ground, it has been known that a portion of the travelling track is configured to be freely separated from and connected with the other portions of the travelling track and is lifted and lowered between the ground and the height position of the travelling track by a lifter (JP Utility H5-82734, JP 2001-278575).

On the ground, the overhead travelling vehicle is stored and placed on a moving carriage, and the moving carriage includes a short track for an overhead travelling vehicle and this track supports the overhead travelling vehicle. Here, it is convenient if the overhead travelling vehicle can be transferred with ease between moving carriages, but it is difficult to align the heights of the tracks provided to the moving carriages. For this reason, the overhead travelling vehicle is transferred between the moving carriages via a lifter. In this case, however, the lifter is used for a purpose different from its intended purpose, which is to lift and lower the overhead travelling vehicle between the ground and an elevated place.

SUMMARY OF THE INVENTION

Preferred embodiments of the present invention lift and lower a track provided to a moving carriage with ease while keeping the track horizontal.

A moving carriage according to a preferred embodiment of the present invention is a moving carriage that moves an overhead travelling vehicle that has been lowered to the ground and includes a frame including travelling wheels; elevating mechanisms provided at a plurality of locations on the frame along a longitudinal direction of the frame; a track for the overhead travelling vehicle, the track being supported by the elevating mechanisms so as to be lifted and lowered and being configured to allow the overhead travelling vehicle to be transferred to and from another track; and a synchronizing mechanism configured to synchronize the elevating mechanisms so as to lift and lower the track for an overhead travelling vehicle by the same or substantially the same amount.

According to another preferred embodiment of the present invention, an overhead travelling vehicle system includes a moving carriage including a frame including travelling wheels; elevating mechanisms provided at a plurality of locations on the frame along a longitudinal direction of the frame; a track for the overhead travelling vehicle, the track being supported by the elevating mechanisms so as to be lifted and lowered and being configured to allow the overhead travelling vehicle to be transferred to and from another track; and a synchronizing mechanism configured to synchronize the elevating mechanisms so as to lift and lower the track for the overhead travelling vehicle by the same or substantially the same amount; a travelling track provided at an elevated place and along which the overhead travelling vehicle travel; an overhead travelling vehicle; a lifter configured to lift and lower the overhead travelling vehicle between the travelling track and the ground in a state in which the overhead travelling vehicle is supported by a track configured to be connected with the travelling track; and another moving carriage including another frame with travelling wheels and another track for the overhead travelling vehicle, wherein the another frame is configured to support the another track at a fixed height. In the present specification, the descriptions related to a moving carriage also directly apply to the lifting/lowering direction of an overhead travelling vehicle system and an overhead travelling vehicle.

Further, a method for lifting and lowering an overhead travelling vehicle according to another preferred embodiment of the present invention is a method for lifting and lowering an overhead travelling vehicle that has been lowered to the ground, while keeping the overhead travelling vehicle horizontal, including a step for providing the above-described moving carriage; a step for transferring an overhead travelling vehicle to the track for an overhead travelling vehicle; and a step for lifting and lowering the elevating mechanisms in synchronization by the same or substantially the same amount by the synchronizing mechanism.

According to various preferred embodiments of the present invention, the height of the track may be adjusted such that the track is lifted and lowered by the same or substantially the same amount at its front and rear of the carriage. Thus, it is easy to transfer the overhead travelling vehicle, for example, between moving carriages. Moreover, a plurality of front and rear elevating mechanisms are synchronized by the synchronizing mechanism, and thus the height of the track may be adjusted while keeping the track horizontal. The moving carriage according to various preferred embodiments of the present invention may be used, for example, as a maintenance carriage to perform maintenance on an overhead travelling vehicle. The overhead travelling vehicle is transferred from a moving carriage that does not include any elevating mechanisms for a track and maintenance is performed on the overhead travelling vehicle. After maintenance, the overhead travelling vehicle is transferred to the moving carriage that does not include any elevating mechanisms for a track and is stored there.

Preferably, each of the elevating mechanisms provided at the plurality of locations includes a shaft extending across the frame in a width direction of the moving carriage; a member to which the track for an overhead travelling vehicle is attached and which is pivotably connected with the shaft; and an axis pivotably supported by the frame and disposed eccentrically relative to the center of the shaft, a driving member configured to pivot the axis is further provided in one of the plurality of elevating mechanisms, and the synchronizing mechanism includes a link or a chain configured to connect the plurality of shafts. Pivoting the axis that is disposed eccentrically relative to the center of the shaft enables the shaft and the track to be lifted and lowered. Further, since the shaft extends across the frame, the track may be lifted and lowered by the same amount at both sides of the frame in the width direction. Then, when the front and rear shafts are connected by a link member, the track and the link member constitute a parallel link, and thus the track may be lifted and lowered by the same or substantially the same amount at the front and rear of the moving carriage. Instead of providing the link member, it is also possible to lift and lower the track by the same or substantially the same amount at the front and rear of the moving carriage by connecting the front and rear shafts by a chain such that the front and rear shafts pivot at the same rotating angle. To achieve these results, the track may be lifted and lowered by the same amount by a single driving member, while supporting the track, for example, at four locations at the front, rear, left, and right of the moving carriage. Note that when no shaft is provided, driving members such as ball screws are provided at the left and right of the moving carriage in the width direction. However, the height adjustment becomes troublesome, and it is difficult to lift and lower the track at its left and right sides uniformly.

Particularly preferably, the track for an overhead travelling vehicle includes a connecting member for connection with a track of another moving carriage. This allows the tracks of moving carriages to be connected when the overhead travelling vehicle is transferred between the moving carriages. Accordingly, when the overhead travelling vehicle is transferred between the moving carriages, there will not be situations where the tracks of the moving carriages become separated by the downward force due to gravity from the overhead travelling vehicle, where impact is exerted on the overhead travelling vehicle due to a gap between the tracks, and the like.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The following describes preferred embodiments for carrying out the present invention. The scope of the present invention is based on the claims, and is intended to be determined in accordance with the understanding of a person skilled in the art with reference to the description of the present invention and related art in the field of the present invention.

FIGS. 1 to 6show a moving carriage2and an overhead travelling vehicle system60according to a preferred embodiment of the present invention. In each of the drawings, reference numeral2denotes a moving carriage, which is used to carry and move an overhead travelling vehicle10that has been unloaded from a travelling track61inFIG. 6to the ground. As shown inFIGS. 1 and 2, for example, four caster wheels5are attached to a frame4of the moving carriage2, and a track6that supports the overhead travelling vehicle10is supported by the frame4, for example, at four locations at the front, rear, left, and right. The overhead travelling vehicle10includes, for example, a pair of front and rear bogie carriages12, supports the overhead travelling vehicle body15by rods13, and a travelling roller14of each bogie carriage12is supported by the track6. Note that the structure of the overhead travelling vehicle10is unrestricted.

The moving carriage2includes, for example, a pair of front and rear elevating mechanisms, and the front and rear elevating mechanisms lift and lower the track6in synchronization while keeping the track6horizontal. Each elevating mechanism includes a shaft20, and the shaft20extends laterally across the frame4in the width direction of the moving carriage2. As used herein, the “front-rear direction” is the longitudinal direction of the moving carriage2and also is the direction in which the moving carriage2travels, and the “width direction” is a direction orthogonal to the longitudinal direction in a horizontal plane and is the short side direction of the moving carriage2. Bearings21and22such as spherical bearings are provided at left and right ends of each shaft20, and the bearings may be of any type. Each bearing21is fixed to a supporting member31for the track6, and the bearing22is fixed to the frame4. Additionally, the front and rear shafts20are connected by, for example, a pair of left and right link members23via the plate24. Reference numeral25denotes a central rod of the shaft20. The central rod25is supported by the bearing21, and the bearing21supports the track6via the supporting member31shown inFIG. 2. Further, the plate24is attached pivotably to the central rod25. The shaft20or the plate24is provided with an eccentric rod26, which is eccentric relative to the center of the shaft20, and the eccentric rod26is supported by the frame4via the bearing22. The shaft20, the bearings21and22, the plate24, and the rods25and26constitute an elevating mechanism.

FIG. 3shows the members disposed in the neighborhood of the shaft20. The eccentric rod26is provided at a position eccentric to the central rod25of the shaft20. Here, in order to increase the amount of eccentricity, the eccentric rod26is attached to the plate24that is fixed to the central rod25, rather than being attached directly to the shaft20. Rotating the shaft20about the eccentric rod26results in a change in the height of the central rod25, which also results in a change in the height of the track6. Then, the shaft20pivots by the same pivoting angle at the left and right ends, and thus the track6is lifted and lowered without being tilted in the left-right direction. Additionally, the link members23allows the front and rear elevating mechanisms to be lifted and lowered by the same amount within the range of mechanical errors.

Reference numeral28denotes a driving member. The driving member28is attached to the frame4, and includes a handle30whose rod is provided with a worm, and a worm, gear29shown inFIG. 4. Upon rotation of the handle30, the worm gear29is pivoted by the worm and acts as a speed reducer for the rotation of the handle30. Since the handle30is not rotated by the worm gear29, it also acts as a stopper.

The track6is divided into left and right sections in the width direction, and the divided sections are connected with each other, for example, by a beam32. Further, when the moving carriage2is connected to other moving carriages, including, for example, transporting carriages64shown inFIG. 6, it is preferable to connect the tracks for an overhead travelling vehicle with each other. Therefore, connecting members34, each of which includes an engaging member such as a hook35, are pivotably provided, for example, at four locations at the front, rear, left and right of the track6, and the engaging members are connected with engaging members, such as pins, that are provided on the tracks of the other moving carriages. Note that the pins or the like may be provided on the connecting members34. Any member may be used as the connecting members as long as it connects the track of the moving carriage2with the tracks of the other moving carriages.

The overhead travelling vehicle10supported on the track6may be moved using a travelling roller14. Thus, for example, a stopper38is removably latched to the plate37that is attached to the beam32. Setting the stopper38causes the overhead travelling vehicle10to be locked as shown inFIG. 2, and removing the stopper causes the overhead travelling vehicle10to be unlocked. Preferably, the track6is provided with openings39such that maintenance of the overhead travelling vehicle, such as the replacement of the travelling roller14, may be performed.

FIG. 4shows elevating mechanisms for a track6according to the present preferred embodiment. Rotating the handle30causes the worm of the handle30to rotate, which in turn causes rotation of the worm gear29meshing with the worm and such that a single eccentric axis26pivots. Pivoting of the eccentric axis26causes the central axis25of each shaft20to be lifted and lowered symmetrically at the left and right ends. The track6and the link member23constitute a parallel link, with the supporting member31and the plate24disposed therebetween. Accordingly, the front and rear shafts20rotate in synchronization, and the track6is lifted and lowered while being kept horizontal at its front, rear, left, and right. In this way, the height of the track6is adjusted.

Although the link member23is used to synchronize the front and rear shafts20in the preferred embodiment, it is also possible to use a chain. Such an example is shown inFIG. 5. Reference numeral40denotes a chain connecting the front and rear shafts20with each other, and a pair of left and right chains are provided. Reference numeral41denotes a sprocket that meshes with each chain40. Here, when one of the shafts pivots, the other shaft also pivots at the same pivoting angle due to the presence of the chain40, and as a result, the synchronization between the shafts20is maintained.

FIG. 6shows an overhead travelling vehicle system60according to the present preferred embodiment. Reference numeral61denotes a travelling track, which is provided in the overhead space in a clean room, for example, and a plurality of overhead travelling vehicles10travel along the travelling track. A lifter62is connected with a portion of the travelling track61, and the lifter62lifts and lowers a track connected with the travelling track61between the ground and the overhead space, thus lifting and lowering the overhead travelling vehicles10between the overhead space and the ground. A plurality of transporting carriages64and moving carriages2according to the present preferred embodiment are disposed on the ground. The transporting carriages64are used to store the overhead travelling vehicles10, and tracks to support the overhead travelling vehicles are supported by a frame equipped with caster wheels or the like.

The lifter62finely adjusts the height of the overhead travelling vehicles, and thus, the overhead travelling vehicles are smoothly transferred, for example, between the moving carriage2and the transporting carriage64, and between the moving carriage2and the lifter62. Then, maintenance or the like is performed on a moving carriage2to which an overhead travelling vehicle has been transferred from the lifter62. During this time, the overhead travelling vehicle is fixed using, for example, the stoppers38shown inFIG. 2. After completion of maintenance or the like, the moving carriage2is connected with a transporting carriage64, and their tracks are connected by the connecting member34. Then, the stopper38is removed so as to cause the overhead travelling vehicle to be transferred to the transporting carriage64and stored there. The elevating mechanism of the present preferred embodiment may be provided on the track of the transporting carriage64, but this is inefficient because the number of the transporting carriages64is greater than that of the moving carriages2. Although the moving carriage2is used as a carriage for maintenance in this preferred embodiment, the use of the moving carriage2is not limited to maintenance. Further, the eccentric rod26may be pivoted by a motor or the like instead of the handle30.

The above preferred embodiment has the following advantageous effects.

Pivoting the handle30causes the shaft20connected with the driving member28to be lifted and lowered, and at this time, the shaft is lifted and lowered by the same or substantially the same amount at its left and right sides. The front and rear shafts20are connected by the link member23, and thus are lifted and lowered in synchronization. Accordingly, a total of four locations, namely, the left and right ends of the front and rear shafts20are lifted and lowered by the same lifting and lowering amounts. Thus, the track6is lifted and lowered while being kept horizontal at its front, rear, left, and right.

The connecting member34allows the track of the transporting carriage64to be connected with the track6of the moving carriage2.

The stopper38allows the overhead travelling vehicle10to be fixed to the track6.

LIST OF REFERENCE NUMERALS