Thread: More Scrapyard Finds !

Hi Guys, From a very wet and windy UK.

Whilst risking catching a cold and getting very wet from near horizontal rain, I went nosing around in my local scrap yard. One of the chaps in the workshop there was busy stripping a tread mill. Unfortunately I didn't get there soon enough to grab the motor, before he had gone at it with a big hammer and chisel to get it off the frame, bending the motor drive shaft in the process.

I did manage to grab the elevating motor and drive mechanism, which came out by removing two clevis pins an cutting the power feed cable. I did note the motor voltage marked on the control PCB, before I left. The whole thing cost me a fiver (£5).

The motor, an Italian made one, runs at 2000 to 4000 rpm, driving an acme screw with a nylon nut on it. There is some wear on the screw and nut, far too much to make the screw useful on a machine. However the motor is virtually silent. It drives a worm and nylon gear wheel, the wheel is supported by two beefy ball races, one on either side of the gear and the whole lot is fastened to the worm. The far end of the worm runs in a nylon sleeve.

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Elevating motor, worm and nut mechanism.

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These two pictures show both ends of the acme screw. You can see signs of wear on the screw and at the support end.

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This is the nylon nut. You can see from the angle of the screws the damage caused by a big hammer. These screws held the arm which pushed the treadmill bed.

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Last a picture of the label on the motor. I've written the voltage on the label.

Anyway for what I've got in mind for this bit of salvage the wear and backlash wont matter, but that is a project for a little later.

Whatever you're building, take note of the duty cycle. It's not exactly a heavy hitter.

Hi there, thanks for your warning, point taken.

I agree 40% duty cycle is not a lot ! However the motor itself is marked 24 Volts DC and for my application will only be run from a car battery long enough to push out a step and then back sometime later, I'm not going to fret about it.

I made an electric drill motor step year before last and it was as noisy as could be ! It could wake the dead at fifty yards. I intend to replace the drive assembly with this elevating motor and drive mechanism, in the hope that it wont be as loud. Plus the fact that I have to take it off the van anyway, because a stone chip got in under the limit switch at the back and wrecked the switch.

Hi Guys,

I will post pictures of the step when I take it off the van. The weather is too bad at the moment for crawling about underneath it.

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This is the drawing of the drill motor mounting. It seems to be the epicyclic gearbox on the motor that makes most noise. All the other drawings that I have are the DFX files.