Trailer prop operating structure

摘要: In a trailer prop, combination of jackscrew and nut for raising lowering the prop including an immovable vertically extending helical type having double start screw structure with pair elements, each element lower downward facing lifting face being directed inwardly generally perpendicular to toward vertical axis provide efficient work by engagement complementary upward first thread face, upper retracting at far less than ninety degrees eliminate tendency overhaul or vibrate down when engaging second distance between faces clearance space non-engaging screw.