Sliding door torsion spring balance, balance Springs under heavy load calculation software design of torsion spring, bringing the balance to their best. Selected import 60si2Mn spring torsion spring materials steel, ensuring service life more than 80,000 cycles. Overhead door balancing shaft to ? 25.4 solid round steel, balance shaft equipped with torsion spring break protection device, this device is able to balance torsional spring break, prevent the door fall upgrade for aluminum columns-rope the rope pulley wheel.