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I've had this three ton gantry crane for a number of years using it frequently. It is physically too large, (18' width) to move efficiently by oneself as it likes to "crab" due to both weight and width. It rolls very easily once it gets going with stopping a problem at times when loaded. With a diesel truck engine hanging from the hoist, it's almost impossible to push it across a smooth concrete floor without assistance although it's mounted on very easy rolling casters.I was thinking a couple of weeks ago how nice it would be to make this thing drive itself. I picked up a hydraulic pumping unit from ebay along with a couple small "Char-Lynn" hydraulic motors from a friend. Also acquired was a small D03 series hydraulic manifold with a pair of 120VAC tandem center electro-hydraulic valves. Needing a set of wheels to provide transfer of the motor torque to the floor, I purchased a couple industrial tires and rims from the local farm supply outlet. After heading into town and picking up some sprockets, chain, and a few shaft collars to connect the hydraulic motors to the wheels, this is kinda what I came up with when it was all mounted up.This setup worked well when the crane did not have a load hanging from it, and gave good control. However, when a one ton load was hanging from the hook, the crane did not have enough tractive effort from lack of enough downforce on the rubber tires to propel itself. The tires would readily spin in either direction but the crane refused to move.SlobPurveyor of intimate unparalleled knowledge of nothing about everything.Oh yeah, also an unabashed internet "Troll" too.....
Reply:A little futher thought applied and the resolution was quite simple with just an adjustable downforce bolt welded into a carrier:The crane now moves effortlessly with a load hanging. It also exibits excellent braking action as the hydraulic valve spools are dampened so they don't slam shut. I have to rig up a joystick affair within an enclosure to operate this and give the ability to steer by allowing one valve to open while the other remains closed for steering either direction. Should be able to get a little of this done tonight after work as I'm thinking everything needed is at the shop. Been a good little project so far and should prove to be quite useful.SlobPurveyor of intimate unparalleled knowledge of nothing about everything.Oh yeah, also an unabashed internet "Troll" too.....
Reply:How are you controlling the motors now? How much weight are you placing on the crane while moving it? Finally, are you thinking about using solid tires to support more weight without compressing as much?Looks good."I thank God for all the freedoms we've got in this country, I cherish even the right to burn the flag, but I'll tell you what, we've also got the right to bear arms and if you burn my flag I'll shoot you"-Johnny Cash
Reply:Hi there, the most I've had hanging on it is a 3350# Caterpillar engine moving it with the tires. The tires carry no weight as the original casters supporting the weight are still mounted up. These tires simply drive the unit. I've not been operating the valves electrically as they can be operated manually also. Jumper wires will make the valves work and the joystick fashion will ease the operation considerably. Right now I can stand next to the manifold and using small screwdrivers operate the valves driving the crane fore, aft, left, and right at will. It will be a lot easier once the electrics are incorporated. I'll probably post up more tomorrow for progress.Thanks,Last edited by Slob; 07-28-2014 at 11:55 AM.SlobPurveyor of intimate unparalleled knowledge of nothing about everything.Oh yeah, also an unabashed internet "Troll" too.....
Reply:That's great ...Way better than pushing it aroundBacked my CATMA over your CARMA oops clusmy me  What would SATAN do ?? Miller Trailblazer 302 AirPakMiller Digital Elite  Optrel Welding HatArcair K4000Suitcase 12RC / 12 VSHypertherm PM-45Rage 3 sawRusty old Truck
Reply:Thanks for the complements guys. You are very correct in necessity is the mother of invention. I no longer have employees and only use the shop to play in and at times miss the help on my projects which are always large. I have to come up with a way to do things by my lonesome and with plenty of time to think, it's either be dangerous, or productive.Spent some time this afternoon locating both a joystick controller, and a medium sized "Hoffman" enclosure. After punching a couple holes in the enclosure and stringing some wiring, all works well. Forward with the joystick drives both wheels forward. Pull the joystick to the rear and both wheels drive rearwards. The joystick moved to the left spins the right wheel forward while precluding the left from moving. To the right and the opposite takes place. By the time some sealtite flexible conduit tied everything together it doesn't look too awful bad. This is not a proportioning joystick, nor are the valves so no variance to flow rates. The valves are dampened on both the opening, and closing so the ramp up in hydraulic flow to the motors is controlled. The crane operates with very little "jerk" when starting, or stopping. I will adjust the operating pressure relief valve to barely perform the task needed which appears to be about 900psi indicated. At idle there is 370psi indicated which is a little high and a byproduct of using small DO3 series hardware. I can go to 3Kpsi, but really no need. With a seven gallon reservoir capacity the unit will run a long time before the hydraulic oil reaches improper elevated operating temperature, hence no cooler. I'll need to fashion some type of guarding for the wheels and drive chain assembly's as open as they are can do some harm down the road I'm certain. Most likely will form something up with radius corners to keep from ripping pants and shins open. Also putting some thought to installing the joystick into as small as possible enclosure as this one is a bit unwieldy to hold in your hands and operate. It is however all that could be rounded up on short order. My memory of junk saved through the years isn't what it used to be......Here's a few photos of the mounted manifold block, valves, conduit runs, and joystick controller. Hope it meets approval:Last edited by Slob; 07-28-2014 at 09:54 PM.SlobPurveyor of intimate unparalleled knowledge of nothing about everything.Oh yeah, also an unabashed internet "Troll" too.....
Reply:Genius!I like it!Very often run into the same problem as you, No Helper!
Reply:Too cool.   I am always modifying things so I can be more productive by myself.   Well thought out.Miller BobcatHarris cutting outfitMiller spectrum 625 plasmaVariety of shopmade tools
Reply:That's very impressive and very useful.  Great job.