I just have a basement home shop. Nothing big or industrial. But I still have to move heavy things. Recently I wrote about a modular tube dolly I built to move things inside the shop. That still leaves the problem of getting things off a truck or trailer. So I built a gantry a few years ago. My original design had height-adjustable legs so I could get the beam low enough to actually roll into my shop. After awhile it became apparent that there wasn't any real use in that feature, and since it limited the beam height it was actually counterproductive. Also, my driveway isn't flat. It slopes sideways about 2" over 10 feet, enough to make a heavy item want to roll sideways in a frightening manner. So my first mod was to add a crossbar with leveling feet. Next I decided to go to Mk. III. This time I upgraded the casters to some really substantial ones that came out of Boeing Surplus years ago. The wheels are 4x8" and each caster is rated for 3500 pounds. The original casters cost me $36 apiece and were rated for 800 pounds. These cost me just about that same price.
The second improvement made in the spring of 2015 is the addition of a rain shield over the chain hoist. It rains quite a bit here in the Seattle area, and I'd rather keep the rain off my hoist. It's just folded up from 23 gauge sheet metal, pop riveted and caulked. It hangs from the trolley.
The final improvement was to lengthen the legs from 70" to 120". Now I can get the hook up to 13 feet, plenty of height. A trailer with a bed 5' wide plus the width of the wheels and fenders rolls under it easily.
I'm very pleased with this little crane. The investment in money and time have been well returned.
Two questions I get are what size is the beam and how did I put it together? The beam is 4" wide and 8" tall I-beam, 8lb 4oz per foot. I used an 18 foot Genie lift in the erection.
Here she is, ain't she a beauty? Note the leveling feet made from 1.25" allthread with 8x8x5/8" foot plates.
Thanks for reading!