A lifting and shoring jack assembly includes a main support assembly having a main column, a jack screw slidably mounted within the main column, and a jack nut engaged with the jack screw and bearing on the end of the main column. A load plate mounted at the free end of the jack screw facilitates...http://www.google.fr/patents/US5680732?utm_source=gb-gplus-shareBrevet US5680732 - Lifting and shoring jack assembly
