Patents Assigned to Pyramid Manufacturing Company--a division of Precorp
  • Patent number: 4172529
    Abstract: The specification discloses a crane including a base having a boom pivotally supported at one end from the base. The opposite end of the boom is adapted for receiving the load to be carried by the crane. A mast and upper tension member system are affixed to the top surface of the boom, supporting the load receiving end of the boom so that the boom structure is relieved of bending moments. Hydraulic cylinders are connected between the base and the boom for elevating and lowering the boom. In one embodiment the upper tension member system includes a spring and dampener which serves to cushion dynamic overloads during operation of the crane. In another embodiment a counterweight is hingedly attached to the end of the boom supported from the base. The weight of the counterweight is borne by a cable which joins into the upper tension member system.
    Type: Grant
    Filed: July 31, 1978
    Date of Patent: October 30, 1979
    Assignee: Pyramid Manufacturing Company--a division of Precorp
    Inventor: John F. Bryan, Jr.