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[SergentEng] Coupler not working properly

Rob Barker
 

this sounds like a problem from a batch of couplers produced two or three years ago.    Frank's been good at replacing them (I had a few bad ones myself.)    First question I'd ask is are these new couplers or older ones you've recently assembled?

Rob Barker
Sydney Australia

PS search archives for stuck open

On Wed, Oct 25, 2017 at 4:54 AM, Edwardsutorik@... [SergentEng] <SergentEng@...> wrote:
 

Over on the Atlas Rescue Forum, several people wrote about a (Sergent) coupler problem.  I quote one of them:


"I can close it with a magnet but it should close on its own without using a magnet looks like the metal ball bearing i blocking it, the knuckle should move that ball up into the upper part of the coupler but its jamming and wont budge."


Several of us either said or hinted that they screwed up assembly.


A couple of days ago, I put a coupler together and experienced the same problem.  I had read the topic previously, so I was very careful about what and where I filed metal.  I DID NOT remove any metal that changed the working surfaces except to gently smooth them.


Anyway, I've just spent some time examining this coupler.  What's happening is the ball is falling from its raised position, partially or completely, behind the knuckle piece.  When this happens, the knuckle cannot be closed.  If one then puts the magnet above the coupler, the knuckle CAN be closed.  This is exactly what the other guys described.


It would appear that the knuckle may be opening a bit too far, thus allowing the ball to drop down.  I did not remove ANY metal in the locations that would control this.


I was about to report my experience back to the Atlas Rescue Forum, but I thought I would stop here first, in case someone can supply additional (helpful) information.



Ed


Edward Sutorik







Edward Sutorik
 

Rob,

It appears my response to your post didn't (yet) show up.  I'll try again.

The couplers are roughly two years old.  They're EC87K.  I've got two packages of six that I was intending on working on.  I've only assembled the one, as it seems wise to put assembly on hold for awhile.

It's good to hear that the bad ones are being replaced.  I'd sure like to hear more about that.  From Frank.  As in:  the protocol.

I did read through the "stuck open" archives, and it appears none of it relates to my problem.  Or perhaps "our" problem, as I mentioned others appear to be having a problem, also.

I look forward to a solution to this problem.

Thanks for the guidance,


Ed

Edward Sutorik

Rob McLear
 

Ed

Rob is correct if they are two years old there is every chance that they were part of the faulty batch that Frank had problems with.  There a problem with the hole in the coupler, it appeared that the mold over time had elongated the hole in the coupler which allowed the ball to move incorrectly.   Frank to his credit replaced all of mine that had been faulty and then took a bit of time to fix the issue with the mold.

I suggest that you get in touch with Frank, explain what has happened and you should get a positive response.   As far as I know there is no way to fix the problem.   When it happened to me I thought I was going nuts as I had assembled about 200 of these before then.  But no it wasn't me it was a fault in the mold, I had something like 15 of these that would not work no matter what I did.

I have over 400 cars equipped with these now and have assembled another 100 waiting to go on to future purchases.   My choice now is the narrow shank with the Accurail coupler box I find that this is an excellent way to mount a good looking coupler on resin cars, and where I can on RTR equipment.   I keep stock on hand for drop in replacements if I can't use the Narrow's both normal shank and short shank couplers.   I would not give up on my Sergents for anything.

Just my 2c worth.

Rob McLear
Kingaroy
Austraila

Edward Sutorik
 

Rob,

I do remember the problem you describe.  I thought the coupler hole elongation problem was just with the "fancy" couplers.  Mine/ours are the type E.

I'm also not seeing how an elongated hole would cause the steel ball to drop behind the coupler knuckle casting.  

I look forward to Frank discussing the matter.

Ed

Edward Sutorik  

Frank Sergent
 

Hi Ed,
 
I looked back to see when you placed your last order. I’m not aware of any type of casting problems that existed in that time period. I think the best way to diagnose this is for you to send me your bad couplers and let me dissect them. Don’t go crazy on packing materials. A plain envelope with the couplers taped to a piece of paper usually works just fine and is cheap to mail. Send to Sergent Engineering, 7620 Crestland Rd. Knoxville, TN 37938. I can get them headed back to you in a week or less.
 
Thanks,
Frank
 

Sent: Wednesday, October 25, 2017 11:44 PM
Subject: Re: [SergentEng] Coupler not working properly
 
 

Rob,

 
I do remember the problem you describe.  I thought the coupler hole elongation problem was just with the "fancy" couplers.  Mine/ours are the type E.
 
I'm also not seeing how an elongated hole would cause the steel ball to drop behind the coupler knuckle casting. 
 
I look forward to Frank discussing the matter.
 
Ed
 
Edward Sutorik 

Edward Sutorik
 

Frank,

Thanks for getting back to me.  I'll do that.  I've got 5 more from this package and 6 from an unopened one.  I think it would make sense to finish out the next 5 or 11 and see if it happens again and/or how often.

But I'll definitely send 'em back so you can check them out.  Well, it ain't "them" yet, only "it".  We'll see.


Ed

Edward Sutorik

Tim L
 

Good to see Frank make an appearance. I tried emailing a few times
yonks ago without any reply.

Just something else to check if you haven't already is to see if the
tang on the bottom half is bent. I had this same ball locking trouble a
couple of times with the diecast couplers until Frank got me sorted.
I was assembling the couplers so that the two halves were assembled
tight to each other at the tang. When the tang is bent this means that
the coupler head is not tight and this was allowing some extra movement
of the knuckle which would then suffer the stuck open problem.
Assembling so the two halves of the head are tight (there might be a
slight gap of the two halves at the tang) usually cures the problem.

Tim
Land of OZ

On 27/10/2017 12:50, Edwardsutorik@... [SergentEng] wrote:
Frank,
Thanks for getting back to me.  I'll do that.  I've got 5 more from this package and 6 from an unopened one.  I think it would make sense to finish out the next 5 or 11 and see if it happens again and/or how often.
But I'll definitely send 'em back so you can check them out.  Well, it ain't "them" yet, only "it".  We'll see.
Ed

Edward Sutorik
 

Update:

I assembled 11 more couplers.  All worked fine.  I had what I consider are a couple of assembly insights, and did things a little differently.

I decided to disassemble ole number 1 myself 'cause now I'm a x-pert!

I did notice that #1 had a wee bit of vertical play on the knuckle.  Not much, maybe a couple of thou.  But noticeably more than all the others.

When I opened 'er up, I found a wee bit of flash at the edge of the lower "ball catching" hole.  Whether that was the problem or not, the flash had to go.  So it went.  That particular flash cleaning is, by the way, a part of my new assembly method; as there was flash in that location on some of the other couplers.

I reassembled the coupler and the primary problem was gone.  So was the vertical play.  The knuckle now closes when it's s'posed to.

It was still a little funny, though, in that the knuckle now wasn't enthusiastic for opening.  Using a magnet, it would work.  But the upside down trick didn't.  I put a little graphite inside.  Wiggled things around.  Removed most of the graphite.  Coupler's now happy.

So it looks like Frank won't be getting my coupler to examine.  But he WILL be getting an order in awhile.


Ed

Edward Sutorik