This invention relates to automotive vehicles having a slideable side door and more particularly to a drive mechanism for a power operated slideable side door. 
U.S. Pat.  No.  5,316,365 granted to Howard W. Kuhlman and Jeffrey K. Joyner May 31, 1994 discloses a passenger van that has a slidable side door.  The door is supported on and slideable in three tracks.  A module for power operation of the door is mounted inside the van adjacent to the center track that supports and guides the rear of the door.  The module includes a front cable and a rear cable.  The front cable is attached to a front cable drive pulley, then extends through a front cable roller guide assembly and is then attached to a roller assembly.  The rear cable is attached to a rear cable drive pulley then extends through a rear cable roller guide assembly, and is then attached to the roller assembly.  The front and rear cable drive pulleys are driven by a reversible electric motor that is driven in one direction to open the sliding door and in the opposite direction to close the sliding door. 
U.S. Pat.  No.  4,932,715 granted to Hans Kramer Jun. 12, 1990 discloses a passenger van that has a slidable side door that is opened and closed by a mechanism that includes a roller carriage in a track.  The roller carriage and hence the side door is driven by an endless round cable that travels in a closed loop with a strand or portion of the cable being disposed in the track and attached to the roller carriage.  The cable is driven by a driving roller which is turn is driven by an electric motor via an electromagnetic clutch.  The electric motor is reversible so that the cable is driven in one direction to open the side door and in an opposite direction to close the side door.  See also U.S. Pat.  No.  5,168,666 granted to Soushichi Koura et al Dec. 8, 1992; and U.S. Pat.  No.  6,081,088 granted to Hidenori Ishihara et al Jun. 27, 2000. 
Copending Patent Application Ser.  No.  09/867,863, filed May 30, 2001, discloses a drive mechanism for power operation of a slideable side door of an automotive vehicle that is characterized by a roller assembly that includes a clutch for clamping onto a flexible drive member that is driven in a loop by a reversible electric motor.  To open the side door, the clutch is engaged and the flexible drive member is driven in the loop in one direction.  To close the side door, the flexible drive member is driven in the opposite direction.  See also copending Patent Application Ser.  No.  09/978,908, filed Oct. 16, 2001. 
This invention provides a drive mechanism for power operation of a slideable side door of an automotive vehicle, such as a passenger van. 
In one aspect, the drive mechanism has a flexible drive member trained to travel in a loop so that an upper portion of the loop and a lower portion of the loop that travel in opposite directions are disposed in a track juxtaposed a roller assembly that is attached to the side door.  A drive mechanism is operatively connected to the flexible drive member to drive the flexible drive member in the loop, and a cinch mechanism is mounted on the roller assembly for connecting the roller assembly to the flexible drive member selectively.  The cinch mechanism has an upper clutch for engaging the upper portion of the flexible drive member to drive the side door in one direction, and a lower clutch for engaging the lower portion of the flexible drive member to drive the side door in an opposite direction.  Thus the side door can be opened and closed without any need for a reversible electric motor to reverse the travel direction of the flexible drive member. 
In another aspect, the drive mechanism has a flexible drive member that is a round cable of uniform diameter and a cinch mechanism for connecting the roller assembly to the round cable of uniform diameter.