US Patent 9789355 Portable escalator

A portable escalator includes a frame, a stair caterpillar, a driving device and a braking device. The driving device includes a motor, a chain-sprocket unit and a belt-pulley unit. The motor includes a mandrel and is connected to the frame. The chain-sprocket unit is connected to the stair caterpillar. The belt-pulley unit includes two pulleys and a belt. The first pulley is connected to the mandrel. The second pulley is connected to the chain-sprocket unit. The belt is provided on the first and second pulleys so that the motor is operable to drive the stair caterpillar through the belt-pulley unit and the chain-sprocket unit. The braking device is connected to the mandrel so that the braking device is operable to stop the mandrel.