There is centrifugation to bump brake mechanism's of pearl lawn mower, the brake mechanism that the pearl was bumped in the above -mentioned centrifugation that is equipped with of band pulley is by multiunit centrifugal slider (27), pearl (28) are bumped in the centrifugation, centrifugation spout (30), the centrifugation stop piece (29) constitute, the pearl was bumped in the centrifugation brake mechanism except that with establish wave form concave arc (32) on job card dish (31) on output shaft (203) take the location stop the effect, the centrifugation is stopped piece (29) and output shaft (203) and job card dish (31) and has been total to to stop and stops acting on, centrifugal slider (27) are die -casting aluminium, centrifugal slider's (27) entad direction earlier the mould pressing of die -casting aluminum component go out two pits again the tight fit pressure equipment go into two steel centrifugations and bump pearl (28). The wave form of wave form concave arc (32) on job card dish (31) is one section that equiangular spiral is also called to the pressure angle logarithmic spiral that equals the characteristic everywhere, or cube curved a section of utensil buffering collision characteristic. Strengthened insurance and brake effect, it is fast and accurate, spare part has still been saved, the cost is reduced.