Patents Assigned to Fru-Con Construction Corporation
  • Patent number: 4616958
    Abstract: An expansible mandrel for use in driving or withdrawing tubular piles has lengthwise sections which are subjected to expanding forces in a plurality of zones spaced lengthwise of the interior of the mandrel to establish their pile-gripping relationship. The pile-entering relationship of the sections is re-established by a series of transversely spaced pairs of assemblies spaced lengthwise of the mandrel with each pair between adjacent zones. Each assembly includes, in the disclosed embodiment, two coil springs each of which is confined in a tube. The tubes are spaced apart lengthwise of and are secured to one mandrel section. The proximate ends of the tubes back the springs.
    Type: Grant
    Filed: November 13, 1984
    Date of Patent: October 14, 1986
    Assignee: Fru-Con Construction Corporation
    Inventor: Nicholas H. Werthessen