Patents Assigned to R. A. Hanson Co., Inc.
  • Patent number: 4324539
    Abstract: A concrete pressure monitoring device in an apparatus for continuously forming an elongated monolithic concrete structure within a prepared excavation. The device includes a pressure sensitive membrane exposed to wet concrete between a bottom surface of the excavation and an inner form member of the apparatus. The membrane covers an open end of a fluid filled housing so that variations in concrete pressure adjacent the membrane will flex the membrane to cause displacement of fluid within the housing. A remote indicator responsive to displacement of fluid within the housing is operatively connected to the housing to indicate the concrete pressure variations.
    Type: Grant
    Filed: May 3, 1979
    Date of Patent: April 13, 1982
    Assignee: R. A. Hanson Co., Inc.
    Inventor: Richard W. Hanson