Patent ID: 8821428

Claim:
A traction apparatus that impresses a desired traction force to a body to be pulled, the traction apparatus comprising: a traction mechanism that includes a harness coupled to the body to be pulled, a rope having a first end attached to the harness, and a take-up drum attached to a second end of the rope and impressing the traction force on the body to be pulled by taking up the rope; a first pulley that engages, at a predetermined wrapping angle, the rope to which the traction force is impressed by being taken up by the take-up drum, a rope load being impressed to the first pulley from the rope; a coupling plate that rotatably holds the first pulley, the rope load being impressed to the coupling plate from the rope via the first pulley; a load sensor plate that holds the coupling plate at a first end portion thereof, the rope load being impressed to the load sensor plate from the rope via the first pulley and the coupling plate; an outer frame that fixes a second end portion of the load sensor plate; a load cell adhered to a surface of the load sensor plate, the load cell detecting an amount of strain of the load sensor plate caused by the rope load; and a rotation mechanism that rotates the outer frame in agreement with a take-up position of the rope on a take-up surface of the take-up drum, the first pulley rotating in accordance with rotation of the outer frame.