Patent ID: 6250485
Filing Date: 2001-06-26
Classification: B66F

Abstract:
An articulated boom assembly comprising:a lower boom, an upper boom aligned in spaced parallel relation to the lower boom, said lower boom and said upper boom located as side-by-side booms in a collapsed stored position, said booms having adjacent articulation ends, a common pivot support located between and connected to said articulation ends with the booms freely pivoting on a common axis, an articulation link unit having a common connector pivotally mounted on said common pivot support between said articulation ends of said booms and pivoting on said common axis and extending outwardly thereof and having an upper boom connector located in alignment with said upper boom in said stored position and a lower boom connector located in alignment with said lower boom in said stored position, an extendable and retractable lower boom positioning unit including a lower hydraulic cylinder unit having a cylinder with a closed end connected to said lower boom and having a piston rod extending outwardly of the opposite end of said cylinder and connected to said lower boom connector of said link unit in said stored position and operable to pivot said link unit on said common pivot support, an extendable and retractable upper boom positioning unit including an upper hydraulic cylinder unit having a cylinder with a closed end connected to said upper boom and having a piston rod extending outwardly of the opposite end of said cylinder and connected to said upper boom connector in said stored position and operable to pivot said link unit on said common pivot support, said common pivot support and said upper boom connector and said lower boom connector forming a triangular support with said positioning units and said booms substantially aligned with each other in said stored position, whereby said upper hydraulic cylinder unit and said lower hydraulic cylinder unit are independently and separately operable to pivot said link unit and are conjointly operable to pivot said link unit and said operation of said upper and lower hydraulic cylinder units positions said upper boom relative to said lower boom from said stored position,and wherein said link unit includes at least first and second one-piece triangular plates having aligned apexes, said common boom connector and said upper boom connector of said lower boom connector are secured to and join said plates at each apex of the plates, each connector includes a pivot member with parallel axes, andwherein said common boom connector includes a shaft unit, said shaft unit includes an upper boom shaft connected to the upper boom and a lower boom shaft connected to the lower boom, one of said shafts being a tubular shaft and extending over the other of said shafts and being pivotal on said other of said shafts, and said link unit including a tubular shaft connecting said first and second plates and with said tubular shaft of said link unit pivotally mounted on said first named tubular shaft between said booms.