Jib cranes range in size from hundreds of pounds to tens of tons. They are known for long boom arms and swiveling or rotational capability. They are widely used in industry to load freight and move equipment. Their greatest visibility may well be on the docks where freighters are loaded and unloaded. This is a homemade portable unit that allows engine removal from vehicles, lifts and moves heavy furniture and equipment, and enables loading heavy items onto pickup trucks.
The unit has a 6-foot high vertical boom with a 4-foot horizontal boom. The vertical boom is welded to a 4-foot wide boom that forms the base of a "U" with two 4-foot horizontal legs. This U-shaped frame is parallel to the ground and has four heavy-duty swivel wheels to allow easy rolling mobility. A 2-foot handlebar with grips is connected to the vertical boom at chest level so the operator can push and pull the unit up to the load. Lifting is performed by an 800-pound capacity handle winch with an automatic brake. Steel pulleys with 5/8-inch bores, bushed with oilite bearings, riding on ½-inch steel bolts at the end of the lifting boom supports the steel cable from the winch, which is mounted on the vertical boom arm.
All of the steel tubing used in the unit is 3-inch by 3-inch 3/16-inch thick square steel tubing. The vertical and horizontal booms are 5 and 4 feet long respectively. The legs are 4 feet long. They are welded to two 4-foot-wide sections of the tubing welded together to bolster the most critical section of the crane, since this double-beam transmits considerable torque to the legs from the vertical boom arm. All critical joints are further reinforced with welded rectangular 3/16-inch thick steel gusset plates 3 inches wide. Six of these should be 9 inches long and two should be 6 inches long. Four of the 9-inch-long pieces should be drilled in the corner quadrants, 1 inch in on a 45-degree line from the corners for the pulley bolts. Choose heavy swivel casters with threaded stem tops and weight capacities of at least 600 pounds each. Match the caster tops with 1/4-inch thick weld plates 5 inches longer than the caster top disk that have a bolthole to match the caster stem at one end (not centered).
Use 1/8-inch type 6013 rods to weld all joints. Grind the welds where gusset plates go flat. This is fine since 6013 rods produce welds with penetration into the space between pieces. When the gusset plates are welded on, the joint will be staggered with contiguous material on two levels and extremely strong. Weld the caster plates on tops of the ends of the legs. Chip and brush all welds with a stiff rotary wire wheel in a high-speed drill. Inspect the welds for well-defined continuous beads. Clean and paint the entire frame. Bolt the casters to the plates. Bolt the pulleys into the top boom gussets where they protrude from the top. Finally, use U-bolts to attach the winch to the vertical boom at about waist height. Put a keying bolt through the winch into the frame. Extend the winch cable over the two pulleys and hang the hook. The winch is now ready for use.
