Centrifugal clutch 18 is provided to mechanically couple power source 12 to work device 14 as the speed of input 15 of work device 14 increases to a predetermined speed wherein the need for the torque and speed conversion provided by non - grounded multi - stage transmission 22 become less necessary 离心式离合器18设为随着工作装置14的输入15的速度增加到预定速度时将动力源12与工作装置14机械连接，此时逐渐不再需要非搭铁多级变速器22提供的扭矩和速度转换。
