From falls screw jack's thread non-self-locking action, is loaded with the brake.
自降螺旋千斤顶的螺纹无自锁作用，装有制动器。
2
The ordinary screw jack depending on the thread self-locking action support heavy item, the structure is simple, but the transmission efficiency is low, the return trip is slow.
普通螺旋千斤顶靠螺纹自锁作用支持重物，构造简单，但传动效率低，返程慢。
3
Safe and reliable: joint design, taking into account the friction on the screw and self Bowl gravity, so that a reliable self-locking joint capabilities.