Patent ID: 6129226
Filing Date: 2000-10-10
Classification: B66C,E21B

Abstract:
A self propelled mini hoist comprising:a mobile hydraulically driven self propelled vehicle having a carriage supported by four wheels;vehicle controlling means mounted to the rear portion of the carriage;a cutout aperture defined in the front portion of the carriage therein, for use by the operative to align the mini hoist over a well bore;a boom assembly integrally mounted on the vehicle, the assembly including:a rectangularly constructed open support frame,a pair of elongate hollow boom chassis, a lower boom chassis and an upper boom chassis,the lower boom chassis having a top end and a bottom end, the bottom end pivotally mounted to the support frame thereof,the upper boom chassis having a distal end and a lower end;a hydraulic double acting main lift cylinder interconnecting between the frame and the lower porton of the lower boom chassis, for imparting the initial lifting force to the booms;an articulation assembly having means for pivotally connecting the lower end of the upper boom chassis to the top end of the lower boom chassis, the pivotally connecting means comprising:hydraulically double acting articulation cylinders, an upper cylinder having one end fixedly attached to the upper surface of the upper boom chassis, a lower cylinder having one end fixedly attached to the lower surface of the lower boom chassis,a pair of spaced apart parallel plates forming a bracket housing, the plates supporting four shaft assemblies for rotation therewith, the plates having suitable clearance holes for rotatably supporting two boom shaft assemblies and two cylinder shaft assemblies, the cylinder shaft assemblies disposed exteriorly of the boom shaft assemblies,each cylinder shaft assembly pivotally connecting the other ends of the upper and lower cylinders,the boom shaft assemblies pivotally connecting the upper boom chassis with the lower boom chassis,whereby upon response to the lifting action of the main cylinder the articulation cylinders are adapted to react such that the distal end of the upper boom will raise perpendicularly upwards;four parallel outriggers mounted approximately at each corner of the boom assembly for stabilizing the mini hoist during the pulling stage, the two front outriggers positioned forward of the cutout aperture of the vehicle, thereby maintaining the center of gravity within the confines of the hoist;a hydraulic winch assembly mounted to the upper portion of the upper boom chassis, the winch assembly having means for connecting to well pipe;a support beam extending vertically upwards from the frame, one end of the beam integral with the frame, the other end of the beam having a channel defined therein, for supporting the lower boom chassis in the collapsed stage; andboom assembly controlling means mounted to the front of the hoist, for allowing the operative to manipulate the boom assembly while visually observing the extension and retraction of the booms,whereby the operative can maneuver the mini hoist to a position overlying the well bore, the well bore thereby within the front outriggers such that the well pipe can be raised vertically.