| 摘要 |
1528696 Self-locking nuts and bolts HORACE DEAL HOLMES 6 Oct 1976 [25 Nov 1975 8 Oct 1975] 41577/76 Heading F2H A locking screw thread which is intended to be free-running relative to the thread of a co-operating member until a predetermined axial load is applied thereto comprises a sloping ramp section 16, 17, or 126 at the thread root, which ramp is inclined to the thread longitudinal axis by an angle such that the ramp takes up approximately half the maximum standard manufacturing tolerance between the thread and the co-operating member's thread in a distance equal to the length of the ramp (0À020 inch) in the axial direction. In Figs. 3-5, a buttress thread on a bolt 11 and a matching buttress thread in a nut 15 both have ramps 17, 16 at their roots. In the unloaded, Fig. 3, condition, the threads are free-running. As the nut is tightened, contact of the thread crests 23, 19 with the adjacent ramps 16, 17 takes up the radial play between the nut and bolt, which prevents loosening of the nut until a positive unscrewing torque is applied. The ramp may be provided on the nut thread or the bolt thread only. The ramp may be incorporated in other thread forms, e.g. Fig. 9, such as ISO threads. |
