Article transport facility

1. An article transport facility comprising:

an article transport vehicle configured to transport an article; and

a delivery device configured to be a delivery destination of the article transported by the article transport vehicle,

wherein the article transport vehicle comprises:

a traveling cart configured to travel;

an elevation unit configured to be raised and lowered relative to the traveling cart; and

a transfer device mounted on the elevation unit,

wherein the elevation unit is raised and lowered between a traveling height that is a reference height during traveling of the traveling cart, and a transfer height for transfer of the article with the delivery device by the transfer device,

wherein the transfer device comprises:

a holder configured to hold the article; and

a self-propelled cart configured to support the holder and travel,

wherein the self-propelled cart comprises:

a wheel; and

a wheel drive source configured to drive the wheel,

wherein the self-propelled cart travels along a traveling path provided on the elevation unit and the delivery device,

wherein the delivery device comprises:

a positioning portion configured to position the elevation unit while the elevation unit is at the transfer height; and

a delivery-side guide configured to guide travel of the self-propelled cart along the traveling path,

wherein the elevation unit comprises an elevation-side guide configured to guide travel of the self-propelled cart along the traveling path,

wherein the elevation-side guide is arranged in such a manner as to be continuous with the delivery-side guide while the elevation unit is positioned by the positioning portion

wherein the delivery device further comprises an elevation guide configured to guide the elevation unit such that the elevation unit is positioned by the positioning portion during raising or lowering of the elevation unit to the transfer height, and

wherein the elevation guide includes at least one guiding surface configured to contact the elevation unit to correct displacement of the elevation unit.

2. The article transport facility according to claim 1 ,

wherein the transfer height is set lower than the traveling height, and

wherein the elevation guide is provided such that a guide start position, at which guiding of the elevation unit by the elevation guide starts, is higher than an upper end of the delivery-side guide.

3. The article transport facility according to claim 1 ,

wherein the delivery-side guide and the elevation-side guide are each a gear rack, and

wherein the wheel comprises a pinion gear configured to mesh with the gear racks.

4. The article transport facility according to claim 3 ,

wherein:

the gear racks are arranged in such a manner as to extend in a traveling path direction that is parallel with the traveling path,

tooth surfaces of the gear racks are arranged in such a manner as to face one side in a width direction orthogonal to the traveling path direction in a vertical view along an up-down direction,

the pinion gear is supported in such a manner as to rotate about an axis extending in the up-down direction,

the self-propelled cart further comprises a guide wheel supported in such a manner as to rotate about an axis extending in the up-down direction, and

the guide wheel is arranged in such a manner as to rotate along back surfaces of the gear racks, the back surfaces facing another side in the width direction.

5. The article transport facility according to claim 1 ,

wherein:

the transfer device further comprises a connection wiring configured to connect the elevation unit and the self-propelled cart,

the connection wiring has a first portion that is fixed to the self-propelled cart,

the connection wiring has a second portion different from the first portion, the second portion fixed to the elevation unit, and

the first portion and the second portion are separated by a distance along the connection wiring that corresponds to a length of a traveling range of the self-propelled cart along the traveling path.

6. The article transport facility according to claim 1 ,

wherein the elevation unit further comprises a restriction mechanism configured to change in state between a restricting state in which movement of the self-propelled cart is restricted while the self-propelled cart is at a predetermined position set on the elevation unit, and a non-restricting state in which movement of the self-propelled cart is not restricted, and

wherein the state of the restriction mechanism is changed with use of upward and downward movement of the elevation unit.