The Many Variants of the Maytag "Chime Actuator"

[lowefficiency]

Anyone happen to know the logic behind Maytag's revisions of the "Chime Actuator" in the dryers (DE/DG 806, DE/DG 808, others?) over the years?

The overall bracket arrangement seems to have been designed around a simple bent wire with a screw & nut. Later on, a molded flexible plastic part (nylon?) replaced the wire, and at some point after that (possibly for the -808 dryer?), it was modified to use a metal rivet type of striker, which was curiously designed to be loose with about 0.15" (about 4mm) of back and forth slop.

The bent metal wire seams dead simple, both in design time and in materials/manufacturing. I know plastic injection molding is very cheap at scale, but it also seems like the automated wire bending machine already in use could have churned out a lifetime supply of chime actuators in short order - enough to make the R&D, particularly the mold making, not worth it for a redesign.

So was there some other goal in mind here, possibly changing the characteristics of the ring itself?

Photos of each style attached, the wire one from the early DG806 I parted out, the plastic+screw which recently failed from fatigue in my late-production DE806, and the plastic+rivet bell from an unknown assembly I picked up on eBay... labeled as a Samsung part of all things! (There may be additional variations as well - that's just what I know of.)

 

[qsd-dan]

No idea why the change took place but I think I have the "Lets Talk Service" document that notates the change. I'll rummage around for it and see if it gives an explanation. My guess is that the newer plastic design is quicker and easier to replace. I've replaced the old wires style using an NOS one and it still took 10 minutes or so of tweaking in order to hit the bell properly without getting hung up or sticking.

 

Last year, the plastic chime broke on my DE808 dryer but I had a spare assembly from a DE806 using the older wire/nut design and I adapted it to work. I prefer the older design as it seems to hold up better and fabricating the wire is an easier fix now that the plastic assembly has long been obsoleted and parts have completely dried up. Later on, I found one (or 2) spare NOS plastic chime assemblies in my stash while organizing it. It would sure be nice to find someone with a printer or ability to repop those using my NOS as a template. Some Maytag dryers into the mid 90's were still using a mechanical chime.

 

[a806de806]

Just wondering if you would be will to part with any of your chime activators?

Let me know, would love to hear it chime again.

 

[lowefficiency]

>> It would sure be nice to find someone with a printer or ability to repop those using my NOS as a template.

That's what I'm thinking I might do, since I also still have one (but just one) chime actuator that hasn't broken yet, and of course have no idea how many fatigue cycles it has seen before I got it. But it's still in good shape for measurements. It would probably take some testing & fiddling to replicate the right amount of flexibility without inhibiting the solenoid pull, but still have it be stiff enough to return to position. It's hard to know if it's worth the effort, when the alternative is to just... bend a wire?

I'm thinking the rivet* style unit might have been an attempt to allow the bell to still ring even if the solenoid doesn't pull *quite* fast enough for the striker to swing the full distance? Or perhaps it could have helped prevent double or multiple rings during a single solenoid pull from a rebound off of the bell? Another theory I have is that it limits the volume of the bell ring, since the initial bell surface displacement would only be from the moving mass of the pin, not the moving mass of the pin plus the pull force of the solenoid...

(* does anyone know the technical term for the smooth pin with a press-fit end? It might not actually be a rivet, that's just the best analogy I could think of to describe it...)

 

[lowefficiency]

Ok, here we go!

This ultimately took quite a bit more work than expected... the plastic Maytag part's functionality was clearly compromised by the need to fit in a mechanism designed for the wire striker. The tolerances gave it a very short flex zone (which concentrates stresses and ultimately limits the lifespan), and the shape of the solenoid plunger cutout was prone to mechanical binding part way through the travel, in a way that only really worked because the solenoid strength could flex the plastic enough to overcome it. Interestingly, the bell strike is also off-axis, which was apparently necessary to clear the existing mounting bracket. If the striker is moved to be more in line with the bell centerline, it will hit on the brackets of earlier machines.

So I didn't make it very far before deciding that duplicating the part exactly based on measurements was not the right way to go. My new design has ~2.7x the length of the flex zone, greatly increasing the bend radius to reduce stress, and a solenoid slot that is lengthened, shifted, and flared so that the plunger can pull without binding even at full travel. It took a few tries to get the thicknesses right, so that the actuator strikes instead of whips, but still has enough flex in the non-hinged part of the arm to allow over-travel (essential to ensure that the striker doesn't impede the switch pull that ends the cycle). I also used a bit more plastic, increasing the height of the flex zone and letting the mount wrap over the top of the metal bracket so less twisting force is applied to the half-depth bridge through the slot.

It seems to work fine - but my print is in PETG and I have some concerns about it softening with the internal temps the dryer cabinet will see. Specifically, a dry cycle could "heat soak" it enough to soften the plastic, then the sharp pull of the solenoid could be enough to permanently deform it. So I'm considering this an experiment. I'll let you know how it goes.

 

[DADoES]

 
Yay!

 

[qsd-dan]

Very impressive!

 

[lowefficiency]

Three days in and all is well so far. It's nice to hear the chime again!

 

[qsd-dan]

Start selling these here or on Ebay, there's a market for them.

 

[rodknock95]

Exciting

I would definitely buy a couple. Mine is broke now and sounds like the doorbell on the movie "The Money Pit"

Blaze
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