amt 4 pole cush drive coupling part number?

[duke1]

hi all can anyone please tell me the part number or where i can find it out,sunrise medical parts list is stupid and it seems not to list the cush drive coupling at all that i can find.
even tried amt website but just has motors no gearbox parts,i know i bought a pair some time ago but cannot find invoice for part number.
any help be great
ps slot type not d type
pps happy new year all!

[rover220]

Don't think you'll find a chair manufacturer selling the cush as a spare part.

[Burgerman]

https://www.aliexpress.com/item/32968110279.html

Theres more than 1 size. Measure!

[martin007]

What function do these screws perform?
With what tool are these screws handled?

[Burgerman]

Those are blanking plugs to bung up the hole where there is no output shaft. They are oil seals on the opposite side, if a shaft is protruding. They are not reusable. You would remove with hammer and screwdriver to get to and replace a bearing/shaft. And replace with new.

[duke1]

https://www.aliexpress.com/item/32968110279.html

Theres more than 1 size. Measure!

hi bm thanks for reply,mine is 27mm x 15mm approx as its hard to measure correct due to the swelling of the rubber part pushing cases apart somewhat,i could see only the size you linked to,is there anywhere else you know of? seems wrong the manufacturers do not sell the cush drive seperate,its like saying you need a new gearbox when the clutch goes on a car,cheers

[Burgerman]

The problem is that motor manufacturers dont generally sell to individuals They sell to industry. In bulk. In batches with the correct motor type, pole count, voltage, with brake at 12 or 24V, with cable length and specific plug/connector, and with a specific gearbox type, ratiom gear material, and motor coupling/cush drive rubber. As a UNIT built to spec for a particular order.

They are not geared up for stock, storage, sales to the public, or distribution etc. So the chair manufacturer has only normally the full thing as a part number to sell. Brushes frequently, and occasionally brake unit complete or drive wheel adapter hub may be available too.

And generally if used normally with hovercraft programming the whole unit wears out together. So parts are pretty pointless. But if you are not "a normal user" you will eat brushes, motor coupling/cush drives and possibly break gearboxes frequently. I know I always do.

You can get motor couplings on occasion from AMT direct if you buy a minimum order. That was 12 from memory... And may get some from other motor manufacturers if lucky. Mostly they are not interested.

You can REPAIR them before they fail though. Theres a thread here somewhere showing what I do. Then they dont fail. It involves sleeving them with steel tube before they fail.

Basically WHILE NEW remove from motors, sleeve in stainless steel tube , squeeze together in vice. And if not tight, use epoxy. Then file and clean up - not done here yet. They fail by splitting and expanding.

See here. I have the T shirt.

[Burgerman]

This happens on EVERY make of motor.

Here is how to repair if you cant do the above BEFORE they fail. But you need CLOSE FITTING HARD STEEL to do the Z thing below. Or that will eventually fail too.

15 year old or more page. That was last updated in 2009... https://www.wheelchairdriver.com/powerchair-fault.htm

[martin007]

Those are blanking plugs to bung up the hole where there is no output shaft. They are oil seals on the opposite side, if a shaft is protruding. They are not reusable. You would remove with hammer and screwdriver to get to and replace a bearing/shaft. And replace with new.

I understand.
My powerchair's engines don't have those caps.
My powerchair have a lot of (>20) years.
I thought the holes were to supply grease to the set.
Do those caps have a technical name?


Taking advantage of the topic I will ask another question.
What are the reinforced clamps that attach the motor to a tube of the powerchair structure technically called?

[Burgerman]

Most dont use those - they are part of the wheelchair. Most rehab modern chairs bolt to a flat plate or to a suspension part.

Those bearing blaking plates are available from bearing suppliers. And also oil seals in the same sizes.

Like this https://www.farrellbearings.co.nz/shop/ ... K72-9.html
They tap in with a hammer. Destroyed usually on removal.

[martin007]

Does anyone know the technical name of these clamps?

[Burgerman]

There are many variations. They have a part number designated by the wheelchair manufacturer. They are similar to saddle clamps. But are not called anything in particular.

[steves1977uk]

For those that are interested what's inside an AMT gearbox, here's a pic of one being disassembled...

And ready for rebuild...

This was a set where the manual gearbox release lever was seized in drive mode on both gearboxes. So my ex-RAF friend said he would see if he could fix that issue and do a rebuild of them.

Steve

[duke1]

For those that are interested what's inside an AMT gearbox, here's a pic of one being disassembled...

amt gearbox 1.jpg

And ready for rebuild...

amt gearbox 2.jpg

This was a set where the manual gearbox release lever was seized in drive mode on both gearboxes. So my ex-RAF friend said he would see if he could fix that issue and do a rebuild of them.

Steve

interesting thanks,may i ask where you find the gears?i can find bearings and seals ok but drawn a blank on the gears and ive got about 6 gearboxes and motors i could refurbish nice having a friend with engineering experience to call on. stay healthy

[martin007]

may i ask where you find the gears?

I also await the answer.

[Burgerman]

I doubt he did. Even pro rebuilders use the old ones. No choice. They are not easily available.

[steves1977uk]

My friend is re-using the current gears that were in there as it would be very hard to find replacements.

Steve

[martin007]

What kind of fat do you use exactly?

[Burgerman]

Grease?
Lithium grease as used in wheel bearings. In this case red and tacky grease.

https://www.amazon.co.uk/Lucas-Oil-1057 ... B0068C5WD4

[duke1]

My friend is re-using the current gears that were in there as it would be very hard to find replacements.

Steve

ok its one of them things,i have a friend whom runs an engineering shop and he was saying they have a thing they call spray build that they are currently using to restore worn camshafts from cars some how it adds a new layer of metal and some lazer thing makes sure its correct dimensions and balanced,one wonders if such could be used to restore gears? not that i would go that far it likely costs loads even if it works, i have a policy of zero waste and will happily sit and dismantle the whole bunch of motors and pick the best bits and put some spare motor sets together ready for the next breakdown!good luck with yours,stay well.

[Burgerman]

Rebuilt motors, even done profesionally are just a clean, paint, clean up commutator, set of brushes, new bearings and MAYBE motor connector. At best they are only really any good as a spare on the shelf in case of urgent need.

They do not replace the gears, the motor shafts inc the commutator. They dont replace the magnets which lose power over time. Or the casings etc. So at best they are refreshed some. But will not be as good as new or as efficient.

Personally I think that if its possible to buy a set of new ones at a sensible price its a better way to go. They will have less backlash, less vibration, and better efficiency, and last longer before they wear out. At least in the UK the price tends to be similar.

[ex-Gooserider]

I also believe (BM doesn't...) that if cost is an issue, the best way to deal w/ a motor issue is to look for used ones - ideally from one of the chair junkyard dealers on eBay... It is a bit of a gamble, but given that most folks are driving in hovercraft mode, and that any dealer that relies on his reputation score is unlikely to knowingly sell junk, it can be a reasonable way to go...

Even better if you can find one is to get an entire used chair of the right model - often costs less than just the motors, and gives you lots of other spares as well...

ex-Gooserider

[Burgerman]

Of course it depends on the motors you buy.

I just bought a set of 8mph 4 pole motors. They appear as new. These are worth buying.

See below.

[Burgerman]

But you would NOT want a 1 year old set of motors that I had used!

All "work" and all are knackered and removed because of noise, exess backlash, vibration, or bad performance. Non were more than 18 months old.

[ex-Gooserider]

True, I probably would not want a set of YOUR motors, given the way you describe beating the crap out of them....

OTOH, most people are driving chairs w/ stock programming and being a lot gentler on them in general.... I don't see a lot of problem in purchasing motors that came from "grandma's" chair that might be a few years old but were just used to go slowly around her house and maybe to the doctors....

Odds of getting gently used parts are probably better in the US as well, going from what I see described on the forums here.... It seems like a lot of the UK users do a lot of mileage outside in their chairs because distances to things are less, and gas, etc. is expensive... In the US distances are generally greater so most US users seem to get in a vehicle to go much of anywhere outside their homes...

ex-Gooserider

[Burgerman]

In the US distances are generally greater so most US users seem to get in a vehicle to go much of anywhere outside their homes...

Thats true. Things are close together, so in summer theres seldom need to drive anywhere. Plus we go to the pub at night. Well I used to do every night for 20 years. Beer and many flaming black sambucas with coffee beans and driving back home not wise

And we spend millions on damned rock salt to make sure our wet pavements and roads are as corrosive as humanly possible which really helps ruin motors. And vehicles. And shoes, carpets and everything else.