牵引座 meaning in English

fifth wheel

Fith wheel lead for calculation of mass distribution
质量分配用牵引座前置距
Motor vehicles - fifth wheel coupling pins - strength test
汽车半挂车牵引座牵引销强度试验
Fifth wheel lead for calculation of length
长度计算用牵引座前置距
Height of coupling face
牵引座结合面高度
Specification for clearance dimensions and fifth wheel positions for tractors and semi - trailers
拖拉机和半挂车的间隙尺寸和牵引座的位置规范