Rail inspection device and rail inspection system

1. A rail inspection device used in an article transport facility comprising: travel rails forming a pair which are installed such that the travel rails in the pair are spaced apart from each other along the lateral width direction; a ceiling transport vehicle that travels along the travel rails; and a guide rail provided at a higher position than the travel rails to allow a travelling direction of the ceiling transport vehicle to be changed at a branching point, and configured to inspect an installed state of a first travel rail which is one of the travel rails in the pair and the guide rail, the rail inspection device comprising:

a carriage having wheels configured to roll on the travel rails and configured to travel along the first travel rail and the guide rail;

a first roller supported by the carriage to be smoothly movable along the lateral width direction and configured to roll in contact with a side surface of the first rail;

a second roller supported by the carriage to be smoothly movable along the lateral width direction and configured to roll in contact with a side surface of the second rail;

a first position sensor fixedly mounted to the carriage and configured to detect a position, along the lateral width direction, of an outer surface of the first roller;

a second position sensor fixedly mounted to the carriage and configured to detect a position, along the lateral width direction, of an outer surface of the second roller; and

at least one rotation sensor provided to the carriage and each configured to detect a rotation angle of one of (a) one of the wheels, (b) the first roller, and (c) the second roller,

wherein the first position sensor is fixedly mounted to the carriage so that the first position sensor faces a portion of the outer surface of the first roller symmetrically opposite the portion of the outer surface of the first roller in contact with the side surface of the first rail, and

wherein the second position sensor is fixedly mounted to the carriage so that the second position sensor faces a portion of the outer surface of the second roller symmetrically opposite the portion of the outer surface of the second roller in contact with the side surface of the second rail.

2. The rail inspection device as defined in claim 1 , further comprising:

a recording portion configured to record, as inspection result information, one of (a) obtained data obtained by the first position sensor and the second position sensor and (b) processed data obtained by processing the obtained data (a), and one of (c) obtained data obtained by the at least one rotation sensor and (d) processed data obtained by processing the obtained data (c), such that the obtained data (a) or the processed data (b) is associated with the obtained data (c) or the processed data (d).

3. The rail inspection device as defined in claim 2 ,

wherein the recording portion records, as the inspection result information, information on a distance between the first travel rail and the guide rail along the lateral width direction at each inspection position, based on a distance between the first travel rail and the guide rail along the lateral width direction calculated from obtained data obtained by the first position sensor and the second position sensor and on a position of the carriage along a direction along which the travel rails extends as an inspection position calculated from obtained data obtained by the at least one rotation sensor.

4. The rail inspection device as defined in claim 1 ,

wherein a centering mechanism is provided to the carriage and is configured to center the carriage with respect to a center position between the travel rails in the pair along the lateral width direction.

5. A rail inspection system comprising:

the rail inspection device as defined in claim 1 ;

one or more recording portions at least one of which is configured to record, as inspection result information, one of (a) obtained data obtained by the first position sensor and the second position sensor and (b) processed data obtained by processing the obtained data (a), and one of (c) obtained data obtained by the at least one rotation sensor and (d) processed data obtained by processing the obtained data (c), such that the obtained data (a) or the processed data (b) is associated with the obtained data (c) or the processed data (d); and

a determining portion configured to determine a presence or non-presence of an abnormal condition in an installed state of the first travel rail and the guide rail based on the inspection result information.

6. The rail inspection system as defined in claim 5 , wherein the abnormal condition in the installed state includes variations in manufacturing accuracy of at least one of the first travel rail and the guide rail, and variations in installing accuracy of the first travel rail and the guide rail, and

wherein the determining portion: obtains a graph that represents a relationship between data that originate from the at least one rotation sensor and data that originate from the first position sensor and the second position sensor, based on the inspection result information; and makes a distinction between variations in the manufacturing accuracy and variations in the installing accuracy based on a shape of the graph if it is determined that an abnormal condition exists in the installed state.

7. A rail inspection device used in an article transport facility comprising: travel rails forming a pair which are installed such that the travel rails in the pair are spaced apart from each other along the lateral width direction; and a ceiling transport vehicle that travels along the travel rails, and configured to inspect an installed state of a first travel rail which is one of the travel rails in the pair and the second travel rail which is the other of the travel rails in the pair, the rail inspection device comprising:

a carriage having wheels configured to roll on the travel rails and configured to travel along the travel rails in the pair;

a first roller supported by the carriage to be smoothly movable along the lateral width direction and configured to roll in contact with a side surface of the first travel rail;

a second roller supported by the carriage to be smoothly movable along the lateral width direction and configured to roll in contact with a side surface of the second travel rail;

a first position sensor fixedly mounted to the carriage and configured to detect a position, along the lateral width direction, of an outer surface of the first roller;

a second position sensor fixedly mounted to the carriage and configured to detect a position, along the lateral width direction, of an outer surface of the second roller; and

at least one rotation sensor provided to the carriage and each configured to detect a rotation angle of one of (a) one of the wheels, (b) the first roller, and (c) the second roller,

wherein the first position sensor is fixedly mounted to the carriage so that the first position sensor faces a portion of the outer surface of the first roller symmetrically opposite the portion of the outer surface of the first roller in contact with the side surface of the first travel rail, and

wherein the second position sensor is fixedly mounted to the carriage so that the second position sensor faces a portion of the outer surface of the second roller symmetrically opposite the portion of the outer surface of the second roller in contact with the side surface of the second travel rail.