Patent ID: 6161816
Filing Date: 2000-12-19
Classification: B66F

Abstract:
A pantagraph-type jack comprising a pair of lower arms disposed in an upward divergent shape and swingably connected at lower ends thereof to a pedestal, a pair of upper arms disposed in a downward divergent shape and swingably connected at upper ends thereof to a load receiving base, upper ends of said lower arms and lower ends of said upper arms being connected to each other through first and second connecting shafts, respectively, and an externally threaded rod rotatably but axially non-movably supported on said first connecting shaft and threadedly engaged with a threaded bore provided in said second connecting shaft, whereinsaid externally threaded rod is formed into a hollow shape, and external threads of said externally threaded rod are provided with a tapered portion formed in a convergent shape over a given light-loaded area from a tip end on the side of said second connecting shaft.