Easy Gantry Crane Lift Conversion

The beauty of a gantry crane is the beam overhead, and the clear access for lifting things.  To make them more useful, telescoping legs put the top beam at a height appropriate for the job — in your garage, or outside, or wherever.  One of the challenges is moving that beam up and down to meet the tasks.  Perhaps especially when the crane is purposefully modular for mobility.  How can you lift and lower that gantry crane beam to meet the needs of the moment?

We’ve seen some pretty cool ways.  Some are simple, some more complicated.  I’ve seen sketchy (violating common sense like this on Crane Safety).  For more crane ideas, check out the Customer Stories.

All along, some of you have asked for our recommendations.  What can we say?  Up till now, our way has been brute force, with 2 people.  Speaking of sketchy, I have done it by myself, but I don’t suggest it.

The Brute Force Gantry Crane Lift

The Gantry Cranes of our DIY Plans don’t come with a means of elevating the main beam.  The focus is minimal components for making the crane mobile.  They are intentionally on the lighter side of industrial – not huge capacity, but certainly not lightweight.

Crane Lift by Brute ForceSo, How do you raise the main beam on your Gantry Crane?

This image shows how we often do it.  The 2×4 (wood board) is the right length so one person can lift it, and the other can insert the pin.  Do one side, then the other.  It actually works pretty smooth and quick.  That said, the process does take 2 people — at least one of which that can heft the crane.

Going down is just the opposite.  Not a big deal.

Oh, but make sure you’re on the protruding bolt ends or something with the 2×4 so it won’t slip.

So, what if you don’t have 2 people?  Or what if you need to do it in a more controlled way?  After all, the technique with the 2×4 relies on brute force.

These are the questions customers are asking.  So, we’re asking them too.  Fortunately, we now have a solution.  It’s not an add-on as some have requested, but if you’re building a new gantry crane, this easy lift is a great conversion to accomplish the task.

Looking At The Possibilities

This field has been plowed a lot of different ways.  Here is what some of our customers have done.
Hydraulic Gantry Crane Lift

  1. Lifting the legs by hand.  It takes a few strong hands, but this technique works.  I’ve done it with my crane plenty of times.
  2. Set it once and leave it.  From a few customers with gantry cranes, that seems to be a theme, but not always.
  3. Hydraulic cylinders.  Adding some long reach hydraulic cylinders or jacks to the legs is a nice way to lift.  It is not quick, up, but certainly can be smooth and controlled.

I like the example in the image.  The cylinders lift the gantry crane smooth and easy with air over hydraulics.  This customer uses Air from his compressor, instead of hand pumping the jacks.

Because of ram length, the rams only lift so far.  To go up or down more, the clamp on the upper leg must move.  It’s a good idea, but does require some extra steps for large top beam movements.

Threaded Lift

  1. Another customer explained something similar, but with a long piece of treaded rod.  Drive it with a drill or air wrench, because that’s a lot of turning to go all the way up.  The image here shows the concept.

I like this too.  It’s pretty cheap, pretty easy, and not too bulky or heavy.  Just make sure the rod is stout or it will bend, because it extends a long way.  Using grease will make it messy, but dry, the internal threads will wear.  This too, may be better with lifting in a couple steps, using a moving clamp like above.

Side Note.

We did the engineering for this design with a threaded rod.  The threaded rod is a column, so the size depends on how far you need to lift.  Here is what we found.

First, calculations are based on lifting 150# (1/2 of the top beam weight + trolley and chain-fall), a full 3.5 feet lift, using a threaded rod (Class B7), configured like in the image.  Note this needs a pocket in the upper leg receiver (dark pink in the image) to guide the top end.

Calculations show that a 7/8″ or greater diameter is required for safety at 3.5′ extension.  For lifts shorter than 2.5 ft, the 3/4″ threaded rod will work fine.

(OK, for those of you that like the nitty-gritty engineering detail, a 3/4″-10 (coarse thread) is on the verge (may or may not fail) at 3.5′ lift.  A 3/4″-16 fine thread is marginal.  Calculations say a 7/8″ threaded rod (coarse or fine thread) is best for this application.)

If you try this, make sure you go up a little on one side, then some on the other side, back and  forth so the top beam does not get too far out from horizontal.

So, that’s where we’ve been mentally.  And, (I have to say) with many other hair-brained ideas.  We won’t get into those.

Then, this next solution appeared.

A Better Gantry Crane Top Beam Lift

The new approach makes use of a very controlled mechanical advantage.  The hand winch.  One winch attaches to each lower leg with the cable going into the leg.  Crank the winch, and the leg will extend.  That will, of course, lift the top gantry crane beam.  Stop at a place where the hitch pin holes align, then insert the pin.  Do that for both sides, and that’s it.

The winches are for height adjusting only.  Do not use the crane without the hitch pins securely in place.  The hitch pins hold the weight that the crane lifts, not the hand winch.  Once the pin is in, release the winch pressure, and the crane capacity is the same as defined in the crane plans.

This method is nice because it does not require “steps” as it lifts the beam.  In other words, it does not require going up a bit, then stopping to move clamps, then going up some more.  The winch is always there, so the release is just the opposite to lower the beam.

Yes, it would be nice to have just one winch to lift both sides, however, the extra parts make it impractical.

This approach is not a retro-fit for an existing gantry crane, unless the lower leg is simply replaced.  It is, however, a great way to build a new gantry crane with the lift.

Some Caveats

Crane Leg and WinchWith every idea, there are trade-offs.  Added function usually requires more parts, for instance.  Here are some more things to consider with this winch lift approach.

Advantages
  1. Lift the beam with just one person.  Do a little on one side, then move to the other, and back and forth.
  2. Relatively low forces required to change the beam height.  Just crank.
  3. The winches are easily strong enough to lift the gantry crane top beam with a trolley or chain fall or other lifting mechanisms.  (Hold the trolley, however, or it will roll from side to side.)
  4. With 2 people cranking simultaneously, the beam can go all the way up (or down) and stay horizontal.
  5. Mechanical hand winches are simple, devices that don’t require other facilities — like air or electricity.  You can put power motors on if you wish, but the basic mechanical design is just simple.
  6. Normal function of the crane is the same.  Load capacity does not change.  Beam height, max and min, does not change.  It is still mobile for rolling around the shop, too.
  7. The concept is simple, and universal for the Mechanical Elements gantry cranes.  New plans will convert any of the current Gantry Cranes in our Shop Tools Department.
  8. Most of the added parts are Off-The-Shelf.  True, some parts are cut from standard steel stock, but most of the components are available in a few days from McMaster.com
Disadvantages
  1. Adding this function is pretty easy when building the crane.  It does not retrofit, however.  If you want it for an existing crane, you will need to build new lower legs.
  2. Because there are more parts, the project will cost more.
  3. The added function adds weight, which makes the crane less mobile.  Also, with the upper leg connecting to the lower leg (via the cable), it is harder to take apart for transport.  The top beam can still come off, but the leg sections should stay together.
Considerations (Not really disadvantages, but things to know.)
  1. Remove any load before lifting.  (This is not different than the standard crane.)  The gantry crane upper beam cannot lift when the crane is holding a load.
  2. A trolley will roll from side to side as the top gantry beam lifts, so you must hold it or tether it for lifting.  (Again, not different than the standard crane.)
  3. With one person, the beam will not stay horizontal when it is moving up.  Lift one side a little, then lift the other.  Of course, while going back and forth, you don’t need the hitch pins, as the winch will hold it.  Pins must be in place before lifting a load.
  4. The winch ratchet increments may not hold the upper legs perfectly at the point to insert the hitch pins.  It may require holding the winch between ratchet steps to insert the pins.

The above lists are not exhaustive, but that should give a good picture.

How To Make The Conversion

Our new Gantry Crane Lift Plans are not an Add-On, rather, a Conversion, because it changes things from the original plans.  The Conversion Plans are separate to avoid confusion, because not everyone will want the winch lift.  Also, some people with an existing crane will want just the conversion.

Converting is pretty simple.  For a new crane build, just choose your crane, then buy the Conversion Plans with it.  Those 2 sets will explain everything you need to build an awesome gantry crane with a pretty cool top beam lifting mechanism.

If you already have a gantry crane build from our plans, you will need to build new lower legs to get the new lift function.  The Upper Leg can easily modify, but the lower is significantly different.  Also, the wheel assemblies can simply transfer to the new Lower Leg.

Good Luck With Your Gantry Crane, Beam Lift Project !!

Full Gantry Crane Model

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