自动车钩连接中心线位置应当是甲、乙两车钩连挂时的公切线。即当甲、乙两车钩连挂时,两钩舌的纵、横坐标轴相吻合的交点,就是30°相切于两纵横坐标轴的基准点o(见图1)。但是,新颁布的GB 4952—85《自动车钩连接轮廓》标准中,对车钩连接中心线位置的标注不够明确。若标准本身不能准确表达车钩连接中心线位置,这将直接影响到计算车辆两车钩连接中心线之间的距 Automatic coupler connection center line position should be A, B two hooks when hanging public tangent. That is, when A and B are hooked, the intersection point of the two knuckles’ longitudinal and abscissa axes coincides with the reference point o (see Figure 1) tangent to the two longitudinal axes at 30 °. However, the newly promulgated GB 4952-85 “automatic coupler connection profile” standard, the location of the coupler connection centerline is not clear enough. If the standard itself can not accurately express the location of the coupler centerline, this will have a direct impact on the calculation of the distance between the centerline of the coupler and the coupler