Connection rail for a rail transport apparatus

1. A rail transport apparatus, comprising:

a rail including a first major rail, a second major rail;

a connection rail connecting the first major rail and the second major rail, the connection rail having a length extending in an extending direction and a width spanning between a first side of the connection rail and an opposite second side of the connection rail;

a first direction control guide on the first side of the connection rail extending to the first major rail in the extending direction of the connection rail;

a second direction control guide on the second side of the connection rail, the second direction control extending to the second major rail in the extending direction of the connection rail in a manner not overlapping with the first direction control guide;

a transport vehicle supported and guided by the rail for travelling along the rail, the transport vehicle including a plurality of roller units, each roller unit having a first roller positioned at a first end on a first side of the roller unit configured to be guided by the first direction control guide, and a second roller positioned at a second end on a second side of the roller unit opposite the first side of the roller unit and configured to be guided by the second direction control guide; and

a forward shift guide configured to guide the roller units as the transport vehicle travels in a forward direction from the first major rail to the second major rail,

wherein the forward shift guide is configured to guide each roller unit of the roller units to a position at which the second roller is guided by the second direction control guide after a guiding operation of the first roller of the roller unit by the first direction control guide is released,

wherein each of the roller units are movable to shift in a width direction of the connection rail,

wherein the first roller is guided by the first direction control guide only when the roller unit is shifted to the first side of the connection rail, and the second roller is guided by the second direction control guide only when the roller unit is shifted to the second side of the connection rail, and

wherein the forward shift guide is positioned on the connection rail and configured to forcibly shift the first roller and the second roller.

2. The rail transport apparatus according to claim 1 ,

wherein the forward shift guide intersects an axis of the first direction control guide extending in the extending direction of the connection rail,

wherein the forward shift guide extends to a a location for abutting on the first roller when the second roller is at the position at which the second roller is guided by the second direction control guide, and

wherein the forward shift guide has a forward-shift abutting surface configured to abut on and guide the first roller.

3. The rail transport apparatus according to claim 2 , wherein a shape of the forward-shift abutting surface in a guiding direction is a sine curve shape.

4. The rail transport apparatus according to claim 2 , wherein a shape of the forward-shift abutting surface is configured such that a velocity of the roller unit, in the width direction of the connection rail, guided by the forward shift guide and traveling at a constant velocity in the extending direction of the connection rail first increases with a constant acceleration, keeps a constant velocity for a time period after reaching the constant velocity, and decreases with the constant acceleration after the time period has passed.

5. The rail transport apparatus according to claim 1 , further comprising a reverse shift guide positioned on the connection rail and configured to guide the roller unit to a position at which the first roller of the roller unit is guided by the first direction control guide, after a guiding operation of the second roller of the roller unit by the second direction control guide is released, when the transport vehicle travels on the rail in a reverse direction from the second major rail to the first major rail.

6. The rail transport apparatus according to claim 5 ,

wherein the reverse shift guide intersects an axis of the second direction control guide extending in the extending direction of the connection rail,

wherein the reverse shift guide extends to a location for abutting on the second roller when the first roller is at the position at which the first roller is guided by the first direction control guide, and

wherein the reverse shift guide has a reverse-shift abutting surface configured to abut on and guide the second roller.

7. The rail transport apparatus according to claim 6 , wherein a shape of the reverse-shift abutting surface in a guiding direction is a sine curve shape.

8. The rail transport apparatus according to claim 6 , wherein a shape of the reverse-shift abutting surface is configured such that a velocity of the roller unit, in the width direction of the connection rail, guided by the reverse shift guide and traveling at a constant velocity in the extending direction of the connection rail first increases with a constant acceleration, keeps a constant velocity for a time period after reaching the constant velocity and decreases with the constant acceleration after the time period has passed.