Overhead hoist transfer apparatus

An overhead hoist transfer (OHT) apparatus, comprising:

• a rail module including a main rail and a first rail, wherein the rail module defines a turning path that extends from the main rail to the first rail;
• and
• a differential overhead trolley being movably disposed on the rail module and including:
• a walking mechanism including two differential wheels arranged on two opposite sides thereof and a driving unit that is connected to the two differential wheels, wherein, when the differential overhead trolley is moved from the main rail to the first rail along the turning path, the driving unit drives the two differential wheels to forwardly roll on the first rail at different rolling velocities;
• and
• a carrying body connected to the walking mechanism and hung on the rail module;
• wherein the rail module includes a second rail and defines a straight path that extends from the main rail to the second rail, and wherein, when the differential overhead trolley is moved from the main rail to the second rail along the straight path, the driving unit drives the two differential wheels to forwardly roll on the second rail by the same rolling velocity;
• wherein the rail module includes:
• a first supplementary rail assembled to the first rail;
• and
• a first switching mechanism connected to the first supplementary rail, wherein the first switching mechanism is configured to drive the first supplementary rail to move between a first initial position and a straight position;
• wherein, when the first supplementary rail is at the first initial position, the first supplementary rail corresponds in position to the first rail, and wherein, when the first supplementary rail is at the straight position, a portion of the first supplementary rail is arranged at the straight path and is located between the main rail and the second rail;
• wherein the first switching mechanism includes:
• a first servomotor assembled to the first rail;
• a first linear guideway assembly connecting the first supplementary rail and the first rail;
• and
• a first linkage member connecting the first servomotor and the first linear guideway assembly, wherein the first servomotor is configured to drive the first supplementary rail through the first linkage member so as to move the first supplementary rail along the first linear guideway assembly between the first initial position and the straight position.

An overhead hoist transfer (OHT) apparatus, comprising:

• a rail module including a main rail and a first rail, wherein the rail module defines a turning path that extends from the main rail to the first rail;
• and
• a differential overhead trolley being movably disposed on the rail module and including:
• a walking mechanism including two differential wheels arranged on two opposite sides thereof and a driving unit that is connected to the two differential wheels, wherein, when the differential overhead trolley is moved from the main rail to the first rail along the turning path, the driving unit drives the two differential wheels to forwardly roll on the first rail at different rolling velocities;
• and
• a carrying body connected to the walking mechanism and hung on the rail module;
• wherein the rail module includes a second rail and defines a straight path that extends from the main rail to the second rail, and wherein, when the differential overhead trolley is moved from the main rail to the second rail along the straight path, the driving unit drives the two differential wheels to forwardly roll on the second rail by the same rolling velocity;
• wherein the rail module includes:
• a first supplementary rail assembled to the first rail;
• and
• a first switching mechanism connected to the first supplementary rail, wherein the first switching mechanism is configured to drive the first supplementary rail to move between a first initial position and a straight position;
• wherein, when the first supplementary rail is at the first initial position, the first supplementary rail corresponds in position to the first rail, and wherein, when the first supplementary rail is at the straight position, a portion of the first supplementary rail is arranged at the straight path and is located between the main rail and the second rail;
• wherein the rail module includes:
• a second supplementary rail assembled to the second rail;
• and
• a second switching mechanism connected to the second supplementary rail, wherein the second switching mechanism is configured to drive the second supplementary rail to move between a second initial position and a turning position;
• wherein, when the second supplementary rail is at the second initial position, the second supplementary rail corresponds in position to the second rail, and wherein, when the second supplementary rail is at the turn position, a portion of the second supplementary rail is arranged at the turning path and is located between the main rail and the first rail.