GB1048151A - Earth boring derrick - Google Patents

Abstract

1,048,151. Mobile jib cranes. OHIO BRASS CO. Jan. 29, 1964 [Jan. 30, 1963], No. 3826/64. Heading B8B. [Also in Division E1] A derrick used for earth boring comprises a pedestal 14 adapted to be mounted on a vehicle 10, a boom 12 pivoted for movement in a vertical plane and adapted to carry a boring tool 30, and boom operating means 18 to swing the boom in the plane and to exert a substantially uniform force on the tool in boom positions both above and below a horizontal plane passing its pivotal axis 16. Fluid operated piston and cylinder units 18 are pivoted to the pedestal at 46 and to the boom at 50, the arrangement being that the angle X (Fig. 4, not shown) of the unit to the boom remains substantially constant. The boom may be pivoted in a generally horizontal plane by fluid motor means, has telescopic sections 22, 26 moved by a piston and cylinder unit 27, and has a head sheave assembly 28 comprising a reel driven through reduction gearing by a fluid motor 28a. The tool 30 is pivoted at 33 to a collar 32 which may be fixed to either section of the boom. The boom and tool may be stowed above the vehicle (Fig. 2, not shown) and a jack 19 stabilizes the vehicle during operation of the boom.