Abstract: A stretch mounting unit includes a unit body detachably mounted on a stretcher, a drive device attached to the unit body for providing an output, a center shaft for receiving the output of the drive device, a coupling that couples the drive device and the center shaft for transmitting the output of the drive device to the center shaft, a roller pressed on the center shaft to produce torque, a carrier swingably disposed on the center shaft, a pair of wheels rotatably mounted on the carrier and rotated by the torque of the roller, and a friction clutch provided rotatably on the center shaft and associated with the carrier for swinging the carrier until one of the pair of wheels touches the ground.