Home Forums General Discussion Technical Questions Doors drift open on a Dover DMC

Hi, we've got this side opening car, where when the doors close,and there are no further calls, and dcl is activated, (and pinch torque ceases), the doors just drift back open about 2", until the control sees dcl change states again, then it powers close again. This process repeats until it faults out.

Gravity wants to pull the drive arm vertical, which pulls the doors open. Looked for a slanted track, and dished belts.

Operator is an HD85

Are these types supposed to have pinch torque, when there is no demand?

No some don't...

You're probably out of adjustment mechanically...

Thanks!

I'm looking at it right now. Hangar track seems titled. Gonna put a level on it.

I had the same problem. I mechanically plummed everything, but still had drift open. There is no door squeeze while car has no demand. Door stops on Dcl. I ended up putting magnets between the door close mech stop on the door oper drive sheave. Worked perfectly. Did have to readj. doors a touch, but worked great.

Vic it sounds like the PDO is not square but sometimes these things can't be found. It may be easier to just fit a door spring to the operator. Its shaped like a crocodiles jaw opening with the top tip over a little. You attach a roller to the car door and when the door is fully closed the roller is in that little tip over to hold the door shut. If you want i can send an attachment with a drawing showing what i mean. You could also attach a spirator as well.

check bearing in the operator, i have had them go bad and some odd stuff start to happen.

Belts may be loose, otherwise operator is not mechanically setup correctly.

Wow, thanks guys! Great answers...

I adjusted everything as best as I could, got the doors to stay shut. But then they were banging the strike! Did a door learn run, still banging. Increased close slowdown distance, increased final distance, decreased close force at all positions, etc, etc, in other words tried tweaking each and every adjustment available in the close direction that could possibly keep the doors from slamming shut. Tried multiple learn runs, tweaked adjustments ad infinitum. No luck... Never had a DMC do this before, we have always been able to adjust them. In fact on this operator, the open adjustments respond as you would expect, no problem getting the open fine tuned.

It's just like the door operator had no ability to slow the doors down, once they were set in motion, no matter what adjustments were made. I concluded that the door board didn't have the ability electrically to slow the doors in the close direction, once they had been accelerated.

Will try a new board tomorrow, if available.

Does this car have a Safe edge? It could be the cam that retracts the edge and the heel of the clutch that is causing the doors to drift open. Adjust the roller to stop on the flat spot of the cam, plus angle the cam to force the doors to the close direction.

When your doors are completely closed, how close is the operator arm to the top of the shaft on the bullwheel? you should have about 1/8" of shaft showing above the arm. If the arm is below the shaft, the door will drift open. If you shortened the stroke, and increased the length of the arm, you will close in about 120 degrees of bullwheel movement. You should be using about 270 degrees of bullwheel motion.

This was a contributing factor to the open drift. Thanks.
The safe-edge retractor and clutch retractor work off the same roller. Takes a lot of force to accomplish that. So we made sure it was fully on the flat spot, plus we tilted the flat spot slightly, just to make sure it wouldnt kick open.

Hmm, ok. I'll take a look at that!
Thanks for the info!

Going out with the new board today.
I still think the board is bad. Because regardless, even if there is some mechanical issue, you should still see some effect in the adjustments, but there was none at all. Even going to extremes, close adjustments could not keep the door from slamming the strike. The only close adjustment that had any effect at all was the overall close speed. But if that was turned down low enough to reduce the slam, then the close speed was at a snails' pace, and not acceptable. It shouldn't be this way. The close slowdown distance should have at least SOME kind of effect on the close, even if there is a concurrent mechanical problem. So the evidence still points to the board, although there might needs be additional mechanical work to be done.

I have encountered this problem and the remedy, at least for me was to replace the door belts then do a door learn.

Funny you should mention this..had one that did the same thing would not change the operation no matter what i did to slow it down..when i was ready to give up..just cleared the clc and door system.logs..and soon i was done and the doors were opening/closing nice and smooth...