Radio Control/Foot Pedal Foundry Hoist Prototype

Here is a quick and dirty video look at my recently installed wireless (no pendant) variable speed hoist. It replaces a chainfall that was somewhat cumbersome as it required at least one hand to operate, the hand chain you pulled on wanted to drag across the mold, and chainfall don’t have a smooth motion as they tend to ratchet and that stresses unsupported sand in the mold. In the video I am only lifting an 85 pound mold and flask in the “high gear” setting on the drill motor. I am confident it will manage 300 pound molds just fine especially in low gear.

The drill motor turns the worm gear hoist.

I used an inexpensive 3-channel RC control to run the servo that depresses the trigger on the drill motor. I use a simple hook stick to push and pull the slightly modified direction selector.

I used a 2” nylon strap on the hoist as it spools smootly where cable can snap as a loop lobs over a previously coiled loop on the hoist drum.

BTW, I said “solenoid” when I meant say “servo”





On some of my larger mold it is very nice to have both hands free to steady a cope or drag section while lifting it on an off the other flask section.

Denis

 

That's beautiful in a Rube Goldberg sort of way and I mean that as a compliment. Tell me that the steel that's all hooked to up top works as a trolley too, lie to me if you have to.

 

Thank you!

No need to Lie (though I would have ;-) ) that piece of 3/8 by 5" by 24" steel connects to two barn door steel wheel trucks that ride in the barn door channel and allow the rig to traverse left and right.

I intend to soon put a little servo on the direction selector on the drill motor and control it via another channel on the RC radio controller via a foot button on the foot pedal box. I wanted to be sure the concept was right before going the whole nine yards.

The reason I used the battery-operated drill motor is I did not want the motor to be tethered to a cable. It could have been done, certainly. But it would not have been as clean as this setup. One battery charge will make a whole lot of lifts.

Denis

PS: I see my fingers are a bit bloodied. That is not due to foundry work per se. I had just had my weed wacker and gas hedge trimmer out doing battle with the blackberries. Where I live, if you don't chop them back a couple times a year at least, they will literally overgrow houses and barns. And their thorns are devilishly sharp. Nice eating for a couple weeks in the Fall, though.

 

Where there is a will, there is a way! Neato!
It does look like something created during an apocalypse.

 

Well, Jason, necessity did dictate the design. The criteria were
1) Reasonable cost
2) NO pendant----foot pedal
3) Variable speed
4) Adequate power to easily lift 300-400 pound mold
5) Traverses to allow setting the flask/mold on the floor for transport to the pouring area.
6) No abrupt start/stop and no roughness of lifting action
7) Safe---worm gear style hoist won't run away.
Denis

 

You got a E-stop on that thing n case the controls go nuts? You've got a nice set-up but sh*t happens. Hope for the best, but plan for the worst and all that.

Don

 

Good point.

That would be the drill motor’s for/rev and lock button right now. Once this setup passes “probation,” making a more formal E-stop would not be too hard. This drill motor will becom dedicated to the hoist instead of being one of its many duties as is the case now. So putting an easily accessible emergency interruptor into its power circuit should not be difficult and would be a good idea.

Denis

 

I made a video (of sorts since I had no one to do the recording) today at the molding bench. In it I am using the foot control hoist and I also show a bit about putting a fairly large and detailed sodium-silicate-bound core into the mold. I find the hoist to be quite powerful and easy to use. I really like having both hands free to manipulate the mold while assembling or splitting it. So far the hoist has functioned flawlessly and is very smooth, a huge improvement over the chain fall I was using.

My apologies for my confusing use of cope and drag as at times the mold is inverted and what may look like cope is in fact the drag.


Also, I tried using a soft artists watercolor brush to apply extra graphite to the face of the core shown. Quick eyes will note that the back of the core is much lighter in color than the metal side. That is due to the graphite. We’ll see tomorrow what difference that makes. The sand for the core includes 5 percent sea coal as is.

The strong back for the core is shown in its most recent iteration. The back is slightly narrower than the core as that allows better visualization of the lineup of the core with the print. It is a vast improvement over the simpler wood back with cruder handles and greater breadth that I had been using.

 

Since the foot pedal control is proving its practicality, I think it is time to harden it a bit against the inevitable bumps and bruises it is likely to encounter in my molding area. Perhaps other guys are more careful. Anyway I wanted to prevent damage from relatively small item falling onto the plastic housing that contains the radio. So, I cut up some bar, angle iron, and 1/4" plexi and made a "roll-cage " for the control. It will not fully resist a 50 pound casting falling on it, but the errant hammer or flask should not smash the control unit. I can still access the setup controls on the unit should I need to and the display is still visible.







Denis

 

I've got a machine at work that runs on a 24VDC motor. I use a speed controller which is several feet away and is currently wired to the motor. I would like to use something like your RC controller and get rid of the wire. I tried a wireless LED light dimmer a couple of times which worked great-until it didn't. I gave up and just wired it. Is your controller a good choice for my application? It doesn't need to be a multiple channel controller, although I could use forward and reverse and of course speed control, so maybe it does.

Turn your sound off if you decide to watch.



The motor in the video has been replaced with a more robust and less noisy one.
This is a prototype of something I am considering refining and putting on the market. I run the heck out of this thing at work. Controls are not my strong point so I thought I would throw this out there.

Pete

 

Petee,

I think what I would do would be to use the RC controller, a servo to turn a potentiometer that would adjust the voltage to you motor via a pulse width modulator. That may sound complicated, but it is really quite simple.

First generate 24V DC power using a 120AC to 24V DC power supply which are cheap and very available on eBay or Amazon. This one puts out a half horse (much more than you need) and costs 21 Dollars.


Then take the current supplied and run it through a PWM like this

https://www.amazon.com/Dafurui-Upgr...v+pulse+width+modulator&qid=1587926535&sr=8-7

Use the RC controller and a servo to turn the potentiometer that adjusts the voltage output from the PWM.

I have a couple tools that I have used PWM's and power supplies to power DC motors and get infinite variable speed. Works very nicely. I used the drill motor on my lift as I wanted no power lines to the lift motor. The battery on the drill supplies plenty of power for my application.

There is nothing technical or difficult about wiring up the PWM, servo, or controller---sort of voltage in voltage out on the PWM.

Servos are available in a great variety and could be coupled directly to the potentiometer on the PWM. If you know an RC enthusiast or go to a hobby shop, they could help you get started if you need that assist.

The three-channel I used was the most basic one available and had good general ratings from the model RC people. So, it plus some sort of servo that the controller can drive would work well.

I've been very happy with my setup. Being wireless makes it so much more convenient to use.

If this message doesn't make good sense, I'm happy to discuss via phone or whatever.

Denis

 

The RC controller was like this

https://www.amazon.com/GT3B-2-4G-Fl...rds=flysky+3+channel+rc&qid=1587927305&sr=8-6

You will need to get batteries for the RC Controller and the receiver that hooks up to the servo. I use Lipos. I did make a modification to the power supply of the controller that is commonly recommended.

Here is a video discussing the the power supply modification---also pretty straightforward.



Denis

 

I jsut came across this remote controlled VFD unit that just might be better for you: https://www.amazon.com/Acogedor-Controller-Frequency-Durability-conditioners/dp/B07NQFG7LM

I would not doubt there are better setups yet. But for me and my setup, the no wires to the hoist either for power or control were important factors. If you can live with power cords to the driven unit, that opens up additional possibilities.

Denis

 

Thanks for your responses Denis. That looks like a pretty simple setup when it's all said and done but it has me rethinking the whole process. My ultimate goal would be to ship the machine to the customer, cash his check and never hear from him again. And the fewer components involved, the better my chances of that are. I know for certain that when I push a button and the machine doesn't turn on, the sooner I can find the problem and implement the remedy the better it is for me and everyone around me. The wire is a bit of an inconvenience but it reduces the components to 12 ft of wire, the oversized wall wart, and the control board with a potentiometer. It also adds details to the build like terminal ends, jacks, etc, but I think the wire is going to be the way to go on this one. Folks in the trade expect cords anyway so I think the extra cost and additional components involved in going wireless would be more than is needed.
There's a lot to think about in this whole project and being able to bounce stuff like this off of others is a great benefit, so thanks for taking the time to explain it.

Pete

 

Pete,

My first reply was, indeed, directed at more of a personal build of item you would use, build, and maintain. But, then I got to thinking about the for sale aspect—-simple and bullet proof has to win over elegance. I would never try to piece together something like my hoist for general sale.

I see there are starting to be some wireless variable speed DC motor controls on the market.

https://www.amazon.com/uniquegoods-Controller-Adjustable-Reversible-Reversing/dp/B01MCYHQRZ?th=1

Of course, you have to wonder about the build quality of such items. But, still it is nice to see options developing.

Denis

 

I saw that item on my way down the rabbit hole last night. I also found myself on Arduino forums, Raspberry Pi, and others, and found myself embracing the wire options once again. It also reminded me that there are some smart and enterprising people out there.
Again I wasnt sure what was available out there. The little on/off fob gadget in my video was about 3 bucks and consists of the fob and that little receiver. That's it. It was about 3 bucks on ebay listed as an led light dimmer. Maybe I cooked it, or maybe it was worth less than 3 bucks I dont know but in any event it was wishful thinking.
Thanks again for answering my questions.

Pete

 

Let me preface this rant with the statement that I am NOT a Safety Nazi.

As a former industrial electrician and current controls engineer with 40+ years total experience, the idea of fabri-cobbling something together for my own use doesn't faze me at all. Professionally I deal with controlling dangerous stuff all the time. That includes stuff that can crush, burn, go boom, or just generally not play nice with others. However the idea of making something like that for sale to others scares the BeeJeezuz outta me, and it should scare anybody else that's planning on making and selling a potentially dangerous product.

I'm gonna paraphrase AvE here:

We as a group are fairly easy-going, and our buddies are fairly easy-going. We know what's safe to do, what's not safe to do, and that stove's will burn us, etc.... If your buddy asks you to do something for him, you'll generally do it. That might even include building something for him that is potentially dangerous, because you know he's fairly careful and won't do anything stupid with it. However, will his wife be as easy-going when she's looking at a body with a bloody furrow where the face used to be, when he was using something that you built?

Think about your liability before you think about building something for sale. I don't know how much liability insurance my employer carries for each of us engineers, but with some of the work we do it's probably a butt-load. When you think about building a widget for sale that could potentially hurt somebody, you've got to think about how much are you willing to lose if somebody sues you. Because if somebody gets hurt it's practically guaranteed you WILL get sued. One of the first things I learned in my engineering law course was that in a lawsuit, the first rule is SUE EVERYBODY! (Somebody will probably pay just to get you out of their hair.)

For a long time I was planning on building an overhead trolley type hoist in the garage on my property. Then I got to thinking that if I sell this property and the next guy gets hurt using that hoist I'd be liable. Now I'm not thinking about the hoist so much, or let's say I'm at least planning on removing the hoist when I leave.

Thus Endeth the Rant for the day,
Don

 

True that!! I work at an airport and I got sued when a 727 pilot messed up his crosswind calculations and slid off the side the runway under icy conditions resulting in considerable damage to his landing gear. My involvement in this, several minutes prior to the incident, I called the tower to report that I believed the anemometer (wind speed indicator) was not working properly due to icing and suggested that they shouldn't rely on the readings, this information was relayed to the pilot prior to landing but it seems he chose to discount it and use the faulty readings instead. I endured many hours of some rather unpleasant discovery sessions with multiple hostile lawyers but eventually, the suit against me was withdrawn however not until I agreed not to counter-sue.

 

Rocco:

Regarding your experience with that lawsuit. What do you think your experience would have been like if you had just installed that anemometer, or worse yet designed AND installed the system?

That's what I'm talking about, and that's what building and selling a widget for this hobby is like. My hat's off to the people that do it, mine just aren't that big and brassy for me to try it. (Is there really any aspect of this hobby that WOULDN'T give the hard-core safety Nazis a stroke?) I'm just saying that you need to think long and hard about your liability before you actually do it.

The thing that scares me about this radio control system is what's going to happen if the transmitter/receiver pair loses communication? I know you can set up the better RC systems to do a couple of things. They can maintain last position, which is not really a good idea when you're moving a crucible full of molten metal at the time. Or you can have them go to a failsafe position, which you better set up to be the off position for the hoist. But you are still left with a hot, full, crucible in mid-air. What do the cheaper RC systems do, and do they do the same thing every time? I don't know, but are you willing to bet your and possibly your families future on it?

Don

 

Don,

A couple thoughts here before we get too concerned about liability.

No one has suggested they should or intend to sell a remote-controlled hoist. No one has suggested or even, so far as I know, thought about using it for hot metal. It lifts sand over my molding bench and auxiliary molding bench table next my molding bench. If it loses control, at worst 250 pounds of sand and mold drops onto my bench. Most likely it would just stall out at its uppermost travel or slowly unspool it’s lifting web. I do not make a practice of having any part of my body on my bench under the mold.

Pete is considering making a very low power laminate roller using relatively low-power motor. I’ll trust as he explores control systems for his roller he has thought about safety and liability.

For me, having a convenient, robust, hands-free hoist has made my operation safer as I have better control over my mold since both hands can aid in positioning it. I learned at a young age working as a raw stock handler in heavy industry how and why to stay out from under heavy (in that job routinely many tons of steel angle, bar, channel, or plate) loads. Hopefully, anyone who wishes to incorporate a similar hoist strategy, will use common sense.

Denis