Block and tackle balance problem

A professional from Wake Forest, NC says:
I've seen a lot of discussions on your site that mention the patent number 5.737.877, but none of them offer the right solution. I've got the same patent number, and your 850 system is close, but not exact. The issue is the MIDDLE plastic part on the existing block & tackle (first photo).

On the 850, the string starts at the top and goes down, but on the patent number 5.737.877 system, the string starts at the middle piece and goes up to a metal piece that gets attached directly to the frame with a screw.

Anything that works for that? Otherwise, we have to use the old parts and the windows still have issues.

Also, the string isn't long enough on the 850 to substitute for the 5.737.877 block & tackle. (see last photo showing (3) different versions of patent 5.737.877).

Do you have something that substitutes for that middle piece?

User submitted photos of window balances.
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Paul from SWISCO responded:
Thank you for posting. Patent numbers aren't the best thing to go on when identifying your hardware. Patent numbers tend to cover a wide variety of parts. That said, I think our Series 850 is a good place to start.

I think the differences you note are only because your hardware is broken. Your cord looks longer only because the cord on the Series 850 wraps around the pegs a few times. The middle piece also looks the same to me. I would carefully examine the Series 850 and try to visualize what your balances would look like if they were not broken.
A contractor from Wake Forest, NC says:
Hey, Paul. Thanks for the reply!

Unfortunately that's not correct. We just used some of your 850 balances to try and substitute for these, and I can vouch they are not the same at all.

The balances are similar in that they have the same shoe, and sting at the end with a small metal eye piece. But all the issues I am writing you about are directly from experience with the 850 balances, trying to substitute for what is shown in the pictures.

So to restate, on the 850, I can verify that:
--the string is shorter than the pictured balances
--the string starts at the top on the 850, and needs to start at the middle plastic piece (as it does on the existing balances)
--there is no middle plastic piece on the 850, but it is needed to substitute for the existing balances
--the top plastic piece on the 850 is not needed (but is easily removed) to replace these balances.

We ended up having the re-use the middle pieces from the existing balances and remove the string from the new 850. So the 850 balances are not a good replacement, but there is no replacement on your site that works as far as I can tell.

I may be able to send you parts to get you a sample, but I may not because we have to reuse the parts since you don't have a replacement.
A contractor from Wake Forest, NC says:
As a follow up, we just heard from the customer that none of the windows are working, because we had to use parts from the old window, since the 850 isn't the correct balance kit.

I think the crux of the matter is that piece in the middle, that is broken on all these original balances for which I can't find the replacement part (photo #1 in my first post). Any idea if you have that part or not?

A contractor from Wake Forest, NC says:
I'll make a site visit to see what we can determine in regard to why they aren't working and get back to you on this.

Also, it may be that the middle piece is the same, but without the string starting at the middle piece, the 850 block & tackle won't work correctly. The string needs to extend up from the middle piece and only up to the end metal "eye" loop, which is installed directly to the frame with a screw. You can see the top end of the block & tackle in the attached photo.

Again, we'll do a site visit and determine if we can give you better feedback on this.

A contractor from Wake Forest, NC says:
I might have to have you delete this discussion and start over once I check behind our guys! Thanks for your patience.

Anyway, I found the old parts in the trash, and you may be right about the middle part being the same. I'm looking into what was done and why the widows aren't working. Perhaps I'll be proved wrong here very soon (hopefully so).

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Paul from SWISCO responded:
Ah, I see. Thank you for the updates! The problem with these old balances is that they aren't even made anymore, so if the Series 850 isn't a match I'm not sure what else to suggest. Even our stock has a limited supply. Let me know what you come up with and we can work from there!
A contractor from Wake Forest, NC says:
Paul, the more we look at it, the more we think you are right. We're finding that the ones that we thought were good, may actually be broken as well.

So to sum it up, there may not be a single good block & tackle in the whole house, even though some of the windows are still operating (somehow).

I think your post steered us down the right path, and the 850 will be the closest match, AND the middle piece is the same piece as the original.

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Paul from SWISCO responded:
Great! It can get confusing when there's not an undamaged balance to refer to. When these things break, everything kind of goes all over the place. Hopefully you will be able to get the Series 850 to work!
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