parbuckle screw松紧螺丝
parbuckle e单绳作的双折吊锁;单绳做的双折吊索;套拉索
N（名词） a rope sling for lifting or lowering a heavy cylindrical object, such as a cask or tree trunk 套拉索
V（动词） to raise or lower (an object) with such a sling 用套索升降物体