Hoist / trolley Chucks

restore49 · Sep 11, 2020

Just another way to move from shelf to machines. VW rear wheel bearing and two serpentine belt idlers. Lifted and moved my fat ass so should be fine for 100lbs. Can not figure how to correct orientation of last picture?? Bob

dalmatiangirl61 · Sep 11, 2020

I read description, and looked at the pics, still not understanding what you are doing, please elaborate.

Garwood · Sep 11, 2020

dalmatiangirl61 said:
I read description, and looked at the pics, still not understanding what you are doing, please elaborate.

Looks like he's got a shop under a concrete upper floor with pan deck ceiling so he attached a VW wheel bearing to channel and attached with a couple small concrete anchors. Then he made a tube inside a tube thing with rollers and hung a hoist on the end.

restore49 · Sep 11, 2020

Correct - 4 - 3/8" drop in toothed anchors rated at 2000lbs each I hope. Will be able to pluck vises and chucks from a shelf swing into place and lower - was limited on space between 3 machines in a circle.

restore49 · Sep 11, 2020

The turnbuckle was to compensate for any deflection - wanted to keep the chuck rolling towards the base not depending on the stop.

DDoug · Sep 12, 2020

Barn door track with the trolley is less "bodging", and work just fine.

john.k · Sep 12, 2020

Risky part is the concrete connection...are anchors good for 20/200/or 2000lb?.....is the concrete sound ?......Sudden failure of concrete,the stuff doesnt bend ,it just breaks.

restore49 · Sep 12, 2020

Needed to be able to clear objects at 34" and extend to 45" to reach furthest lathe spindle with chuck - so Barn door track would not work - this will slide like a greased pig with 150lbs hanging. In theory the anchors are good for 2000lbs each - the concrete is my only concern???. Not clever enough to figure the load on the VW bearing hanging 250lbs at the full 44" extension ( hope it is less than 2000lbs spread over 4 anchors)? Bob

drcoelho · Sep 12, 2020

Yikes, cantilevered off concrete ceiling.....not something I would recommend.....

john.k · Sep 12, 2020

Or stand near while in use.

Garwood · Sep 13, 2020

restore49 said:
Needed to be able to clear objects at 34" and extend to 45" to reach furthest lathe spindle with chuck - so Barn door track would not work - this will slide like a greased pig with 150lbs hanging. In theory the anchors are good for 2000lbs each - the concrete is my only concern???. Not clever enough to figure the load on the VW bearing hanging 250lbs at the full 44" extension ( hope it is less than 2000lbs spread over 4 anchors)? Bob

You have a 44" lever there to pop those anchors out.

I think the math would show you are way beyond capacity of those anchors.

drcoelho · Sep 13, 2020

It's not just pull down stresses in play here, there are sideways stresses on the anchors due to the cantilever effect, I don't believe those anchors have 2000 lb strength when confronted with varying sideways stresses. Just seems like a very dangerous and risky scheme, and could possibly undermine the concrete ceiling over time as well.

OP should consider a proven solution like a bridge crane or similar, mounted on floor.

john.k · Sep 13, 2020

If such a scheme was essential ,then I would drill right thru the concrete floor,through bolt, and place a plate on the top surface to spread the force of the bolts ......The OPs design relies on the tensile strength of concrete ,a risky thing to do,even if within theoretical limits.

drcoelho · Sep 13, 2020

john.k said:
If such a scheme was essential ,then I would drill right thru the concrete floor,through bolt, and place a plate on the top surface to spread the force of the bolts ......The OPs design relies on the tensile strength of concrete ,a risky thing to do,even if within theoretical limits.

Agreed, plates on top/bottom would be better, but I would engage a mechanical engineer to do an analysis and would also want to know the exact spec of the concrete.

I_AM_MACHINE · Sep 13, 2020

Garwood said:
You have a 44" lever there to pop those anchors out.

I think the math would show you are way beyond capacity of those anchors.

250 pounds working on a 44" lever arm (need to divide the 44" by twelve to get into feet) yields 917 foot pounds. Typical code crane load LRFD (load and resistance factor design) criteria I believe is 1.6 for crane loads. 917 foot pounds multiplied by 1.6 equals just under 1500 pound, divided by four fasteners equals 375 pounds per fastener. If, (and that's a big if), as the OP stated, the fasteners are rated at 2000 pounds each, that's a factor of safety of 5.33, so he's probably ok. Having said that, I would not stand under it...

Kevin

drcoelho · Sep 13, 2020

I_AM_MACHINE said:
250 pounds working on a 44" lever arm (need to divide the 44" by twelve to get into feet) yields 917 foot pounds. Typical code crane load LRFD (load and resistance factor design) criteria I believe is 1.6 for crane loads. 917 foot pounds multiplied by 1.6 equals just under 1500 pound, divided by four fasteners equals 375 pounds per fastener. If, (and that's a big if), as the OP stated, the fasteners are rated at 2000 pounds each, that's a factor of safety of 5.33, so he's probably ok. Having said that, I would not stand under it...

Kevin

But that's a static load. This thing is moving all over the place, causing stresses in multiple directions....those fasteners are being pulled down and side to side IN CONCRETE! Might hold for first year of its life, then might pull out anytime after that!

Cole2534 · Sep 14, 2020

I_AM_MACHINE said:
250 pounds working on a 44" lever arm (need to divide the 44" by twelve to get into feet) yields 917 foot pounds. Typical code crane load LRFD (load and resistance factor design) criteria I believe is 1.6 for crane loads. 917 foot pounds multiplied by 1.6 equals just under 1500 pound, divided by four fasteners equals 375 pounds per fastener. If, (and that's a big if), as the OP stated, the fasteners are rated at 2000 pounds each, that's a factor of safety of 5.33, so he's probably ok. Having said that, I would not stand under it...

Kevin

I think you have missed the boat here. You attempted to convert a moment load to tension but they're not compatible in this case because the fasteners are not evenly loaded. The one(s) in the back are in compression, ie not helping at all, and the ones in the front (toward the jib) are not much more heavily loaded.

We do agree though, this isn't something anyone would put their name on.

Simple, worst case-
If you assume a 6" bolt circle with 4 holes and the 250lb load 44" from the center with the load 45 deg from the axis of an opposing pair (so if your bolts are at 12, 3, 6, 9:00, your load is at 1:30 or 4:30). The forward holes, toward the jib, are 2.12" from center, as are the rear bolts. It's probable that the front bolts will see stress before the rear, and so now you have 2 bolts holding 250lbs against a 44:2.12 leverage ratio. That'd yield about 2600lbs each. Depending on the design of the base plate, and how rigid it is, one could feasibly put the full load on a single fastener at a 44:3 ratio or about 3670#.

As one case imagine, broad rigid base becomes very important.

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