Design Challenge: Improve Paint Booth Hooks

I would make the hook with a quick connect clamp, something like this

...but with this mechanism

...and keep it covered with a plastic sleeve...

....or you could use a twist lock coupling setup....use an air ratchet to attach and remove ...this would be a two step process of installing the fitting on the tank, and then twist locking the hook assembly on...

....or this and a fitting with a hole in it...

Well... we already screw on the hook. That's what I'm trying to eliminate; screwing something on. It would address the ergonomic factor, but I don't think a two step process would be any faster than the one step of screwing on the hook. Thanks for the suggestion, but I don't think that's the answer.

There may be no good solution, but I thought I'd throw it out there. You never know if someone will have that light bulb turn on above their head.

You could weld a tab on the opposite side and just cap the threads....?

No, I can't alter the tank itself. That would also add a significant bit to the cost of the tank. I can absorb the one-time cost of altering the hooks since only a few hundred are constantly being reused. But adding a cost to each of the hundreds of thousands of tanks per year would be prohibitive.

I would think about slicing a section of the female threaded portion in a way that allows the tank to be placed into the threads .. and then the cut away piece replaced and secured with a boot to hold the works together.

tough one.. simple, but tough

You and lyn might have something there. That was actually my first thought; some kind of clam shell arrangement Although... if it were a straight thread, it might work. I might be worried since it is a tapered pipe thread, and there would only be 1/2" of engagement. On the biggest 92 lb. tanks, that might be unreliable. There is also the issue of it getting a layer of powder coat each time. Still, I haven't completely eliminated the concept.

What if you split the female section in half and used a sliding sleeve to lock it around the male portion. Sleeve up, female coupling opens enough to accommodate the male part. Sleeve down, locked onto the male part.

Details are sketchy otherwise.

Assume it's electrostatic, hand sprayed?

Wait a minute... Did.??. nah

You could split a coupling and weld a loop on it, and use a quick clamp...

Sorry. Never mind.

Bye.

Drill a hole in the fitting,,,insert pin into clevis yolk on end of hanger...

I was thinking along a similar line.

How to keep the male thread clean?

Will machining time (or increased piece expense) match or exceed that already being spent on the existing routine?

I don’t suppose the vessels have a skirt on the other end, do they?

Unfortunately, drilling holes through the fitting would affect the seal between the threads on the tank fitting, and the eventual plumbing that would be attached to that fitting. This is a pressure tank.

If the tank can withstand a vacuum would it be possible to make a rubber suction cup on the end of the rod and branch this off to a vacuum pump. Let air pressure do the job. Alternatively make a 3 jaw chuck that grips the top of the neck when supplied with air pressure. It could be designed to activate when placed over the neck. Incorporate the mechanism into the suspending rod. Paint them a pretty blue and away you go.

These hang inside a paintbooth, getting powdercoated; hundreds at a time, then continue down a hanging conveyor to the next station. Under the suction cup would be left unpainted. And I can't have it "powered" in any way since a continuous line of these travel a long way throughout the plant. But thanks for the suggestion.

What about a rubber olive with a long compression cylinder and eccentric lever cam at the top.

Like the thing you attach to the valve on a car tyre to inflate it, but, with a much longer cylinder (to avoid cam getting painted).

Does this make sense, or do I need to draw something?

I'm not really sure how those work, inside. I'd have to research that a bit. But... I believe the cam would get painted. Currently, after the many powder coats on each hook, after it gets to a thickness of 3/8" to 1/2", we throw them in the furnace to burn it all off periodically. I don't believe that assembly could survive that. But I will look into this type of mechanism. There might be something there.

Thanx.

If the rubber compression element was at the end of a long tube and the guts could be pulled out, then the outer tube could go to the furnace for burnout and the guts could be reinserted. Alternatively, the outside of the tube could be coated with conformal silicon release coating and the OD of the tube could be mechanically stripped of powder coating.

That was almost a good solution, but the 3 hole sizes are 5/8", 3/4" and 1". Too big for any detent pins on that list.

It's worth further consideration. I gave my thoughts and concerns in reply to jesW55

Yes!

jesw55 and you suggested what I remembered from long ago, just couldn't verbalize it or find an example.

I've never seen this before. I kind of think I understand the concept. I'll have to look into this. It seems like the threads would get painted, though. It goes through an automatic, electrostatic powdercoat booth.

This might be a possibility. Although the fact that it's a tapered pipe thread... I wonder if that would be an issue.

Good Day to you.

Option 1:

Have you considered a pipe coupling sawed (split vertically) with hanger bracket (tee?) welded to one half. Then use a rubber clamp to secure (see below). Paint buildup on the rubber should flake off with flexure, should not matter on the split coupling which would cover the tank threads from the paint.

Option 2: another type of split coupling with quick release:

Option 3: quick release clamp like Tri-Clover makes. This sanitary one is hand spring opened, it will be lighter on clamping power if the wing nut is not used to secure the assembly.

Option 4: expansion plug into tank fitting with tee handle to tighten (this would require a separate sleeve to cover the threads unless the plug was slotted to slip over and extend both inside and outside the pipe but would still require multiple turns to secure and loosen so I'm not sure if this would be any better than the threaded pipe).

Regards.

You could make an expanding 4 finger metal ribbed assembly with a inverted wedge shaped insert, so that when the insert was pulled outward the grips expanded and when pushed in, the grips release....the teeth would need to be hardened steel and the wedged insert could be directly attached to the hook, that way as long as there was weight on the assembly the grip would hold, and likewise when the weight was otherwise supported the grip would release...

This concept was my first thought. Wasn't quite sure how to pull it off. Now, seeing yours, I was envisioning the wedge being more like the shape of a golf tee, and having the hollow tube that it went through, having four legs by cutting it twice in a cross pattern. Pulling the tapered tee up into the tube, by applying weight, would spread four the prongs. The tube with the prongs would have to be resilient, to keep coming back to original shape after the inner golf tee was pushed back down. Perhaps I could make the pronged tube from some type of inexpensive engineering plastic. Possibly nylon. The whole thing is basically like an expanding anchor bolt. Does that make sense? I don't have any teeth though. What are the teeth doing?

A limiting factor that must be taken into consideration, is the rubber diaphragm inside the tank, that is right up against the hole in the tank. It's a complete cup shaped rubber lining that covers the entire half dome of the end of the tank. It will push in a little bit... maybe half inch to 3/4". I have to be very careful to not risk damaging that lining in any way.

The four arms could have a spring clip around them about midway, and machined to fit together tight and have a ring though the top portion with a hole in the middle for the shaft of the 'golf tee' expander shaft....the teeth on the bottom outer portion of the arms would be to grip the inside of the pipe wall...I think about 3/16" clearance would be enough between the pipe wall and the grip assembly....maybe a piece of foam rubber on the bottom of the wedge....

NOT TO SCALE

NOT TO SCALE OR PROPORTION

How about a cup with a strong magnet welded to the hook. The cup covers the threads and opening while the magnet holds the assembly to the hook. It just needs to be a strong enough magnet.

This might not be easy to make. But, how about something like a chuck on a brace or a collet like on a Dremel moto-tool, but instead of having to tighten it by screwing it down, it could have a couple of quick-release levers on it? The collet would clamp down on the tank nipple. It could be threaded to not damage the threads.

You didn't mention how the electrostatic charge is applied. Does this hook need to have electrical contact to the tank? Or is just the powder-coat charged?

"You didn't mention how the electrostatic charge is applied. Does this hook need to have electrical contact to the tank? Or is just the powder-coat charged?"

Good answer question.

Something like a logger's-tong that auto-grips the log for dragging? that'll work. It's a lot simpler than my idea.

I just noticed jesw55 suggested something similar, but I think you could do without any ID threads. The steel threads of the tank would bite into the HDPE.

How about a braided-wire tube, like for pulling cable (Chinese finger puzzle)? Just slip it on, and slip it off. But, I have no idea if the coating will make it stop working. Maybe it will flake off by flexing it, maybe it won't.

Look up "Folding Impeller" for design ideas. Used in production or lab environments. It is a toggle attached to a rod that fits through a small opening then pivots outward to mix material in the container. In your application it would simply toggle closed, insert through hole, allow to toggle open and support the tank from the inside.

Yes, I thought of that. That's a great idea... until I remembered the rubber diaphragm that lines the entire half dome of that end of the tank, inside. So you can't really go past the bottom of the fitting, into the tank. The rubber flexes a little, but not enough to have those impeller blades have enough room to unfold. That rubber lining shoots down several concepts that would otherwise work.

I would use a spring loaded scissors type arrangement with a shield cup or just a piece of un-threadded tube stock to cover the outer threads. squeeze the scissors so they are skinny, insert into neck and release and the scissors open up again inside to support the tank.

Or a rod through a tube that is split on the end or hinged so you can push the rod in to push the mechanism in, then pull only the rod to expand it inside and hang it. To release push the rod in and pull the tube.

Or make a lever-action stop-cock like a test plug for plumbing, and add a shield to it for the threading.

I'd look at a push button release ball detent pin that fits the ID of the port into the tank. Add a silicon rubber cup fixed on the shaft that pushes over the threads and a silicon rubber boot over the pushbutton.

In use, push the button and insert the pin. check the coverage on the threads and release the button. Hang, spray and when done, push the button and pull the silicon rubber cup off the threads while removing the pin.

Final step, send me much money.

Yeah, same concept. Quick and easy. Squeeze, insert, release and expand, viola!

I started to respond to this and say what I siad above to someone else who suggested this. That they didn't come in sizes big enough. But... I spoke too soon. They do indeed come in sizes that would fit a 3/4", 1/2" and 1" hole, which are the three sizes of fittings that I have. This might actually work! Have to buy a couple and test them out. One of the problems is that at the largest sizes, I can only find them in SS, which may make them prohibitively expensive. But I'll have a look!

I am considering a provisional design using a pneumatic expanding mandrill with an integral pilot operated check valve. A hand held air gun with a rubber tipped nozzle is pressed onto one valve port and triggered to expand the mandrill and another port to contract it. The non return valve locks in the air and keeps the mandrill expanded while it passes through the oven. But I need to check how much the trapped air will increase in pressure in the elevated oven temperatures, if the seals are suitable and to get a handle on the costs. What temperature does the powder coating oven operate? What are the internal diameters, internal grip length and respective weights of the three sizes of vessel? What quantities are required? If the shaft of the hanger is covered in silicon rubber will a silicon boot which is slid down to cover the mandrill, valve and external tank thread peel powder paint off the shaft covering as it is slid back to disconnect the hanger?

How about a simple and cheap toggle? All metal, one hole for the bolt holding just the toggle piece with a movable cup to protect the threads. Link the cup to the toggle with one piece of wire and the cup acts as a "toggle on toggle off" handle as well. Easily made and dirt cheap.

Re:- peeling the powder coat off, years ago i had some parts plated in Niflor which is a nickel/PTFE composite coating. We had the assembly with these powder coated & found that you could peel the coating off of the plating by hand.

Do the flats beneath the threads on the neck have to be powder coated? Can something grip below them and hold the tank? A cup that has a through-hole for a hitch pin clip that is inserted (after the cup is put over) and slid under the flats.

fill a balloon with water sit on the threads remove after painting -- just the right amount of water and right size balloon -- or condom

Separate the threaded collar from the hook.

Apply and remove the collars using a battery powered drill; fast on and off, eliminating ergo issues.

Use double-ended hooks to hang collared tanks for coating.

....or just use robots....

How does that help hold the tanks?

Wanted to give y'all an update on the results of this design challenge. Had some excellent out of the box creativity with all your suggestions. But I did end up going with something Nigh first suggested, and then Jfalt also, independently I believe, suggested. It's the push button ball detent pin. I machined a shallow groove just inside the opening of the adapter, just deep enough for the 2 balls to pop into and lock in place. When the button is pushed, it releases easy as pie. Still have a bit of design work to do, to be able to protect from powder coat, certain areas, but that looks promising, too.

Anyway, thanx to all for your ideas. I will post a photo of the final product once it's all beta tested and part of our production line