Transport apparatus

A transport apparatus for transporting a carriage base, comprising:

• a body;
• a fork having a shape extending from the body, the fork having one portion supported by the body and another portion protruded from the body, the fork is insertable into the carriage base and extractable from the carriage base, the fork being inserted into the carriage base when transporting the carriage base using the transport apparatus;
• a lifter including one or more links;
• a controller configured to control at least the lifter;
• a primary rotatable structure mounted at a front end portion of the fork via the lifter, a relative position of the primary rotatable structure with respect to the fork is changeable using the lifter;
• an auxiliary rotatable structure mounted at least at one rotatable structure-attaching position of the fork closer to a front end portion of the fork compared to the primary rotatable structure along an insertion direction or another rotatable structure-attaching position of the fork closer to a rear end portion of the fork compared to the primary rotatable structure along an extraction direction of the fork, the auxiliary rotatable structure is settable at a position where the lowest point of the auxiliary rotatable structure is lower than the lowest point of the primary rotatable structure when the fork is lowered using the lifter;
• and
• a step detector, disposed at least at one detector-attaching position of the fork closer to the front end portion of the fork compared to the auxiliary rotatable structure along the insertion direction or another detector-attaching position of the fork closer to the rear end portion of the fork compared to the auxiliary rotatable structure along the extraction direction of the fork, the step detector detects a step structure formed in the carriage base,
• wherein the controller lowers the fork using the lifter in response to a detection of the step structure by the step detector.