Shop Potential modification of Shop Crane for parallel feet

[Dabbler]

@StevSmar I looked at modifying my shop crane, and felt a build from scratch might give a better outcome. So I have begin assembling piles of cheap steel to fabricate from. I originally thought an adjustable width would make storing smaller, and make it more versatile, but the extra structure makes it very heavy, complicated, and compromises rigidity.

I don't have your CAD skills, and prolly my specs will be different from yours, but I've been thinking along these lines for a couple of years (I take forever to get my projects started). I took 3 years to design my gantry crane, a year to build it, and I've been improving it ever since!

you might consider using the upright, boom, cylinder and some of the steel as kit parts and build your crane from scratch using them. Just a thought.

 

[wmetfab]

Something that might add safety, add weight at the bottom to lower the CG
Respectfully

 

[PaulL]

Generally speaking, I am alone when I move things.

Wiser words I've raraely heard spoken. When I'm alone I can avoid rushing things, avoid cutting corners, avoid straining, and I know where *all* the fingers and toes are.
Anything too heavy for one man to move is pretty much by definition too heavy for more than one man to move.

 

[StevSmar]

Nice work on the cad

My Wanna-Be CAD designer bows down... Wow...

Thanks for the praise. CAD is my "Something to do in front of the TV when my wife is watching a show I'm not interested in". I get lots of practice.

If you use your original design, but add two more crosswise receiver tubes (going left to right so to speak) beside the first set, you could have your width adjustment vary a lot more, with much longer tubes to start with.

That's a great idea! I bet it will most probably eliminate the need for any "in-out" extensions.

...Generally speaking, I am alone when I move things.

I've demonstrated that this is probably not a good idea for me... There have been a few times where my actions have occurred faster than my common sense. So a safety watch is beneficial for me, even if I physically do the work myself.

I find it easier to lift things up onto blocks that are higher than the legs, then put the hoist into position, move the machine, lower back onto the blocks, and then from there back to the floor...

I think why I'm set on having the feet parallel is that I'm annoyed at how much of a pain the original shop crane splayed legs were. Even if my Mill stand is on blocks, I'll still have difficulty "threading" the feet in.

...you might consider using the upright, boom, cylinder and some of the steel as kit parts and build your crane from scratch using them....

That's what I'm hoping to do and I think the next version (posted below) accomplishes this.

Something that might add safety, add weight at the bottom to lower the CG
Respectfully

That's a good suggestion. Even moving the lathe (without the stand) it was very easy to get the lathe swinging (while unwisely moving it across patio stones without plywood down....).

 

[StevSmar]

This is the latest iteration, the feet are fixed at 1000mm apart and cannot be moved back or forward, though they still can still swing up for storage using the original scheme.
For this version I won't have to buy very much material:
- Blue=existing parts/material.
- Green=material on hand.
- Red= material to purchase (looks pink in the above).

I had the model for the Stand and Mill, so I thought I better insert them to see if I even have enough vertical travel. It will be tight...

In above the front wheels are moved in so the pins can be inserted from the inside. I doubt I'll ever do that so if this gets built maybe I'd move the front wheels out a bit. The front wheels are only for storage however, so maybe they're good as is?

This version does have some issues though:
- With the boom extension in the 1 metric ton position, the cranes feet will foul the wall. So this means I probably won't be able to move the Mill and Stand as one piece. I should probably be separating the Mill from the Stand when making major moves around the shop anyway... So maybe this is not an issue.
- I'll likely need to remove the Mill head to put the Mill onto the stand. I think I can work around that though.

This version is definitely a lot less complicated than the first version I posted.

 

[StevSmar]

If you use your original design, but add two more crosswise receiver tubes (going left to right so to speak) beside the first set, you could have your width adjustment vary a lot more, with much longer tubes to start with.

I REALLY liked your suggestion, so I drew it up to see what it would look like. Much better than my first design.

This is with the feet moved together as close as they can be (600mm in my model):

And then the feet moved out to what I would guess is the maximum width:

Above has about 250mm of inner tube slid into the outer tube:

I don't know if that's a reasonable amount of overlap thats required for structural stability, but with 250mm you end up with about 49.8" between the feet:

The existing feet look like they're long enough:

This design definitely satisfies most of my original requirements:
- The feet can be moved in and out, with a range of 600mm to 1320mm (24" to 52"). 600mm so I can get behind my lathe. 52" so I can straddle a 48" pallet.
- The feet can be moved backwards, so the crane can get closer to loads that are up against a wall.
- It can be pulled apart into pieces which are somewhat flat, so that when it's not in use I can pull it apart and store it under my desk or shelf.

I think I'm still leaning towards the design where the feet are fixed at 1000mm apart and the existing swing up capability is used. I'll mull over it and decide- this will likely be a fall project so I've got a bit of time to make the decision.

 

[Dabbler]

My original design featured this design, but if you put it through strain analysis (I don't have FEA), you find that the forces twist the sliding tubes... a lot. Square tubung is vulnerable toi twisting loads, weakening them considerably. I settled on multiple fixed receiver tubes at varying distances away from the upright mast.

 

[djberta]

Stev Smar, love your cad. The Last design looks the most versatile for sure. If you’re worried about the 250mm not supporting enough you could put plate top and bottom to reinforce that section, at the same time the casters can mount off the plate. Inside the tubing you can weld some reinforcing. Even a decent fitting price of angle will help and in this case it would not have to be very long. Drill holes in the tubing then weld the reinforcing to the tubing and clean up. Also you could add another set of casters on the ends of the legs and this would add support.