Vacuum wheel with separate contact and vacuum surfaces

A support table for supporting and transporting a substrate, the table comprising:

• a plurality of pressure ports that are distributed across a surface of the table;
• a plurality of vacuum wheels, each of the vacuum wheels being mounted to the table such that an end of each of the vacuum wheels extends beyond the table surface, each vacuum wheel comprising:
• a fixed conduit that is connectable to a suction source;
• at least one vacuum surface on a circumference of the vacuum wheel, the vacuum surface including a plurality of vacuum openings that are distributed around the circumference, such that rotation of the wheel causes the vacuum openings of said plurality of vacuum openings to successively fluidically connect to the fixed conduit such that, when suction is applied by the suction source to the fixed conduit, the suction is applied to one or more of said plurality of vacuum openings that are currently fluidly connected to the fixed conduit;
• and
• at least one contact surface on the circumference of the vacuum wheel, said at least one contact surface being adjacent to and extending outward beyond the vacuum surface such that, when the suction is applied to said one or more of said plurality of vacuum openings, the substrate is drawn toward the vacuum surface, so as to contact said at least one contact surface without contacting the vacuum surface, and so as to apply a friction force between said at least one contact surface and the substrate to transport the substrate when the wheel rotates.

A support system for supporting and transporting a substrate, the system comprising:

• a plurality of idler wheels whose axes of rotation are parallel to one another;
• a plurality of vacuum wheels whose axes of rotation are parallel to the axes of rotation of the idler wheels, each vacuum wheel comprising:
• a fixed conduit that is connectable to a suction source;
• at least one vacuum surface on a circumference of the vacuum wheel, the vacuum surface including a plurality of vacuum openings that are distributed around the circumference, such that rotation of the wheel causes the vacuum openings of said plurality of vacuum openings to successively fluidically connect to the fixed conduit such that, when suction is applied by the suction source to the fixed conduit, the suction is applied to one or more of said plurality of vacuum openings that are currently fluidly connected to the fixed conduit;
• and
• at least one contact surface on the circumference of the vacuum wheel, said at least one contact surface being adjacent to and extending outward beyond the vacuum surface such that, when the suction is applied to said one or more of said plurality of vacuum openings, the substrate is drawn toward the vacuum surface, so as to contact said at least one contact surface without contacting the vacuum surface, and so as to apply a friction force between said at least one contact surface and the substrate to transport the substrate when the wheel rotates.