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Connecting Link; 3/8" Chain

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DAVIDSTECKER

DAVIDSTECKER

Mechanical
Mar 23, 2005
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I had this posted over at the gear and pulley group, but didn't get any replies so I thought I'd try this group.
I'm looking for a full strength rated connecting link for 3/8" Grade 100 chain that will fit in the pockets of this chain wheel.
This is for a close loop system for moving carts though an assembly line.
I'm making the drive with the chain wheel and the customer is somehow making the connection, I assume by welding a link that they have cut and welded back into place.
The Figure 8 connectors are too big for this application.
In the marine industry we use Stud Link chain and there are Kenter links that work with the windlass, but that type of chain starts at 3/4".
I've been looking PEWAG chain and accessories, but they only go down to 22mm.
Any leads would be greatly appreciated.
Best regards, David
 
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I know of great options up through 1/4", btu 3/8" in interesting.
What is wrong with a pin break tool, just push a pin most of the way out and then make up the chain and push it back in.
What does Diamond sell for this application?

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, consulting work welcomed
 
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EdStainless, What you are describing sounds like instructions for Roller Chain.
I'm working with Coil chain used for lifting and such.
2022-01-06_09.10.23_ukgw90.jpg
2022-01-06_09.10.23_ukgw90.jpg
 
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Same problem as previous requests - the only way to get the strength on Grade 100 chain is to have solid welded links. Alignment pins, bolt holes, screw holes, any holes of any kind to join pieces will drop the strength of the joining link too far unless the section of the link can be far larger than the base link. Which with that drum/wheel, it cannot be.

Were it possible the chain makers would sell them. Buy chain in 100 ft or 500 pound increments and buy links to make whatever length you wanted. That the chain makers don't do that is evidence they can't. That no one else that makes such links makes what you want suggests is isn't possible - this is not rocket science. Either fitting into that space or producing one that is affordable (Perhaps someone has a $1000 maraging steel link) is eliminating the item from the market.

Design a chain wheel that will work with available links or set up an operation for welding chain loops for your customers.
 
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Does the chain slip if a figure-8 connector goes across the windlass, or do the remaining links keep enough grip to let it pass? Or are there issues with the larger connector link allow lateral slip that "de-rails" the chain?

I doubt you will find any information about joining Gr 100 chain, it's an alloy steel and welding it would ruin the temper adjacent to the weld and lower the strength - no stateside manufacturer is going to help, because they make OSHA/ANSI/etc. compliant products that must meet strength and safety standards. It sounds like your customer is making it work, probably because they don't really need the full strength of the Gr 100 chain, but it has better fatigue and wear resistance, and breaking the welded link occasionally is just par for the course for them?
 
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3DDave
I have welders in house that I know would have no problem welding a link back together, but we also have equipment to follow a weld procedure.
The end users that I have been supplying re-placement machines to have somehow manage to make the connection for a long time now, the pocket wheel is from another company that they have been using for years also.
We are mainly in the marine business, but somehow one of our capstans turned out to be a good replacement for the manufactured home business, so I'm on a learning curve, as I've been approached to supply complete systems for new plants.
I'd rather not rely on a field weld making the connection.
For Stud link anchor chain, a Kenter Link is our go to for linking shots of chain.
I was speaking to an engineer from the chain company the other day about them making a continuous loop, but they are limited to 50' and I'm looking for 400'.
 
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LittleInch, right idea, but the 2,700# WWL is way below the 8,800 of the chain.
Based on what they have given me for weight, I calculated a pull of about 7,600#

btrueblood, as this is a new market that seems to have found us, I haven't been able to experiment with the pocket wheel that they have been using.
I've just been buying it from the guy that has been supplying them for many years.
This drive system is in many of their plants, so I'm trying to stay with what they have since they first came to me for replacement parts.
The engineer at the chain company thinks he recalls a company that does make what I'm looking for, but he needs to see if he can locate the source he saw.
Thank you for your input.
Keep it coming.
Best regards, David
 
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btrueblood, they only have enough room to stretch out that much to get all of the twist out. At the end users place, they do.
I believe that the links are heat treated just as soon as they are welded, it's been awhile since I've watched video.
The massive Stud link process is amazing.

3DDave, Hence my search for the mythical chain link. LOL
In house we have many welders with unlimited thickness NAVSEA / AWS welding certificates.
This assembly is kept above 300deg for the next 3 months of welding after the root passes have been X-rayed.
Love the new induction heaters.

2022-09-12_13.28.39_daiuiu.jpg
2022-09-12_13.28.39_daiuiu.jpg
 
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hendersdc, Yes, they are 100% rated, yet too big for the pocket wheel.
Since I first posted this, I have designed a sliding hook that I can use with another type of chain fitting, but the system will oscillate back and forth instead of continuously run in one direction as they do now.
Unfortunately, this adds about $23,000 to the cost.
 
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1. It seems that this is not an overhead lifting application
2. Have you made chain pull calcs - is this thing over-spec'ed
3. Can you upsize chain and reduce chain grade to reach an acceptable link strength
chain_oa8fve.jpg

4. Can you get lower-rated links and load test
link_g4ypcu.jpg
 
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DavidStecker said:
Based on what they have given me for weight, I calculated a pull of about 7,600#
Click to expand...

Perhaps you should share your calculation.

In thread725-498176 last September you provided a link to this video, showing the pull chain at 3:52.

Rolling resistance:
Fr = c W

where

Fr = rolling resistance or rolling friction (N, lbf)

c = rolling resistance coefficient - dimensionless (coefficient of rolling friction - CRF)

I see two chains and eight wheels, or one chain pulling four wheels.

So:
7,600/4 = 1,900 pounds pull per wheel.

Let's just for fun imagine that c=1.

That would mean that each wheel is supporting 1,900 pounds. 1,900 * 8 = 15,000 pounds.

Does that pallet weigh 15,000 pounds? I don't think so, but it might.

But, look at the typical values for c.

The largest c in the table is 0.4, and that's for car tires on loose sand. Hardly your case.

All the other values are much much less. I don't see a great match for the wheel/tire in the video, so let's see what happens with "truck tire on asphalt" c=0.01.

Does a pallet weigh 1,500,000? No way!

Let's guess that a pallet weighs 50,000 pounds. I think that's pretty conservative. With c=0.01 and two chains, that's a pull force needed of 500 pounds.

Are they pulling 15 pallets at once?

It just doesn't seem possible that 7,600 pounds of pull is needed.
 
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DVD and MintJulep,,
I have two of these projects going right now, the first actually measured the starting, (750#) and running pulls (350#) with a scale.
The other is based on an estimated weight of the modules.
The calculation I use is for moving railroad cars which has other derating variables to account for rail bed and temperature.
The second project has 18 modules, the estimated weight I was given is between 40,000 to 56,000 per module.
I compared the actual to the calculated and I'm think that I'm right on the money for the loads.
6,600# to 7,650#
The machine is capable of generating 36,000# at start up.
As I mentioned before, currently I'm stuck with the pocket wheel at this time.
How the customer is currently making the connection I do not have the detailed process, but I'm assuming they are welding.
As the manufacture, I can't leave it up to them.
Again, thank you for your input.
Best regards, David
 
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