Uni-strut hoist

[dagnew]

This is my first project post. I would like to share a few pictures of my recently completed overhead hoist project. It spans from one mezzanine to the other so some of the larger infrequently used tools can be moved up there to free up floor space of. The Harbor Freight hoisting unit is rated for 1300 pounds and is the weakest link of the assembly. The 20 foot lengths of P5001 Uni-strut was found on Craigslist from a warehouse demo. Both the trolleys (rollers) and Simpson strong-tie hangers were purchased on eBay.

Enjoy,
Dan

 

[gregtwojeeps]

That is some serious looking trolley work, nice job. So, how much load do you figure it will handle in transit safely ?

 

[ADSR]

Wow! That's awesome and took some real planning!

 

[Nowater]

Where did you, or how did you find the allowable loads for the Uni-strut? You have double unistrut that is then welded to more double unistrut--was there a specification to match on the weld? Thanks.

 

[Steevo]

That is an awesome job on that Unistrut bridge crane.
I really like the design a lot.
When I was in the unfinished stage with all trusses exposed inside, I was planning something very similar. I was going to run it the length of my shop at ceiling level, and had even started buying parts, when I found out that my trusses were not rated for the load, even if I spread it across all of them equally.

 

[akdiesel]

dagnew

You found some nice pieces of strut. That is a heavy duty and well thought out system.
I would like to only add one thing... And that is your max load limit seems a bit high. The strut is more than rated and evenly distributed but the week point to me appears to be the Simpson nails and location. The whole beam system is not seeing the load but maybe four or five of the trusses.

 

[kent_323is]

First, nice job on the construction, and implementation of this.
That said, and echoing some of the others, I am a bit leery of putting a 1300 lb load on that. Did you do any calcs or have it reviewed by a structural engineer?
You may want to consider doing some proof load testing by lifting incrementally heavier loads just a few inches off the ground, and the measuring deflection of the beams, joists and connections, and inspecting each connector carefully. You should do this in several points, middle of cross beam, end of cross beam, and then with cross beam centered between joists, and the centered at one joist.
I would hate to see you trying to lift something too heavy and pull the roof down on yourself, or have one of the connectors give way.
I would also agree with akdiesel that at max only 4 or 5 trusses are seeing the load at any one time, which will decrease the allowable load.
Typically crane systems have a safety factor of at least 4, which means the allowable loads on each of those connectors shoul be divided by 4.
I don't know that the harbor freight crane is the weak point....

Let us know the results of your testing and feedback from a structural engineer.

Again, looks nice tho. Some more pics of the garage would be good too, looks like a nice one!

 

[bad_idea]

I like it.

 

[saceone]

I like it too. Isn't it awesome when function meets form!

 

[dagnew]

Re: Unistrut hoist

Thanks for all the comments and concerns. I will try to answer your questions.

Each trolley is rated at 600 pounds at 30 feet/minute.

Unistrut has a general engineering catalog online that lists capacities of each type. The doubled P5001 Unistrut seen in the picture is needed to span the 6-1/2 foot spread and support the intended load capacity. The factory spot welds their P5001 Unistrut. The previous owner had welded the P5000 Unistrut together to create the P5001. I just repeated the staggered welds. I've seen the factory spot welds and am sure the current assembly is stronger.

The Simpson hangers and supplied hardened screws are rated at 1800 pounds. I agree they won't hold that much with the screws so close to the edge, but each one won't even be subjected to 1/2 of that.

You are correct, the hoist is not the weak link. I should have said that 1300 pounds is the capacity of the system. The joists/trusses are on 24 inch centers and the larger sliding assembly is 36 inches wide to span 1-1/2 joist bays. The roof is designed to support my intended load. That being said; for piece of mind, I don't plan on using it if there's a foot of snow on the roof.

I do plan on checking deflection under load and will inspect the connections as you suggested. I have engineered drawings for the roof and it's capacities.

Thanks again for the positive support and concerns.

Dan

 

[kent_323is]

Dan,
Good to hear that it sounds like you've done your homework on this one. Nice implementation, with the proper design to keep everyone safe.
Now let's see some pictures of it in action!

Kent

 

[1/2 Cup]

Now that's a top idea, well done.

 

[sunsation288]

wow nice work !!!
well done sir