Re: [SergentEng] Couplers sticking open

James Koretsky


This is quite timely actually, as I spent labor day weekend assembling and installing Sergent Type E's from the bulk packs on some TOFC cars, ready for use at a show coming up in Syracuse, NY in November.

I had one that was sticking open, and wouldn't close without some serious force. I found just like you, that there was a little piece on the arm that I hadn't cut off (I wasn't checking this at all, as most of the ones that I'd assembled were perfect), so it wouldn't go back in letting the ball drop, without some brute force. I put the coupler aside and disassembled it later on with some acetone and was able to trim it off, and file at and clean it up, and I made sure to make sure that I didn't cut too much off, then filed the rest off.

Since I bought some Optivisors through my Eye Doctor, assembling these couplers has been a breeze and operation has been perfect. The optivisor are perfect for finding any tiny pieces of flash that need to be removed.

Thanks for your solution, should I remove too much, I'll look at what you did to resolve.


----- Original Message -----
From: "Ryan Harris ryan.harris@... [SergentEng]" <SergentEng@...>
To: SergentEng@...
Sent: Wednesday, September 16, 2015 7:53:13 PM
Subject: [SergentEng] Couplers sticking open

Back when the discussion started about the coupler manufacturing
problems I looked through my couplers to see if I was affected. It turns
out that while I had a few bad actors among the hundreds(!) of couplers
I had assembled, none of my problems could be attributed to the
design/manufacturing flaws that were brought to light.

After playing around with some of these couplers it finally occurred to
me what was causing the problems I have been having of the coupler
locking in the open position. On my problem couplers, when the knuckle
is opened the ball is able to fall behind the knuckle tab and get
trapped behind/slightly under the tab, which locks the coupler open and
prevents the ball from being raised by the magnet or by gravity if the
coupler is turned upside down. If I force the knuckle open just a bit
more, the ball can return to the raised position and the knuckle closes
freely again.

When I assembled these couplers (the plain Es purchased in packs of 144
and the lower shelf and double shelf Es in packs of 6), I noticed some -
very few, in fact - of the knuckle castings had a little extra material
on the end of the tab away from the knuckle itself. This extra material
had to be removed and apparently I wasn't as careful as I could have
been in removing it. I inadvertently made the knuckle tab a bit too
short, which has the effect of allowing the knuckle a greater opening
range of motion. This extra swing allows the ball to get trapped behind
as I described above.

The simple solution to this problem is to replace all the offending
knuckles. Frankly that's a bit of a pain, especially on those cars where
the installation was a little difficult (I'm talking about you,
Intermountain covered hopper kits) or where I've weathered everything
and don't relish the thought of damaging the finish of the car. For
those cars I have devised a solution that involves me cutting a small
slice of 0.030" styrene square rod and glue it into the slot that the
knuckle tab moves through at a point farthest away from the knuckle.
This limits the opening range of the knuckle by a small amount, but by
just enough to prevent the ball from falling behind the tab.

Anyway, I'm glad to have finally found not only the cause of this
problem but also a solution.

Ryan H
Fort Worth, TX

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