TREADMILLMOBILE
Treadmillmobile
The concept of this project is so stupid you'd think that it must have come to me in a dream, but it didn't. Sometimes I just can't resist temptation. Somebody was giving away a free *broken* treadmill that apparently had been critically wounded as it flew from the back of a pick-up truck into the ditch at 60 mph. So with a free treadmill in hand, the question was what to do with it? A big chunk of garbage that has a DC motor rated for a couple horses, a speed controller and a track. With it being winter and snowy and all that, the 'treadmillmobile' idea kept popping back in my head, probably becuase I couldn't come up with anything better. With no more than an idea and this sketch, I began building; what did I have to loose?
What I Got
Mr treadmill had gotten banged up a bit when it flew into that ditch. The handles were bent and loose, tread didn't seem to have much power and it made some funny noises. I spent a couple of hours having a look at the system to see what was in there. The main problem was that the track was pulling to one side and rubbing on the frame due to a broken tensioning device. I tightened some bolts, added a sheet metal screw to repair the busted track/tread tension device and adjusted the track tension. After this work and some fresh batteries for the display, mr treadmill seemed to work just fine. Motor has RPM of about 5500 at maximum speed controller output voltage of 94 VDC. The DC motor is rated at 2.25 HP at 120 Volts with an intermittent rating and rated at 1.3 HP for continuous duty at 94 VDC. So now I had a perfectly fine working treadmill, ready for testing. I'm not much of a runner, so I decided to test out the operation of the treadmill under load by riding my electric RAZOR scooter (also rescued from the trash) on it at max speed. Well it turns out my scooter can just barely keep up with the treadmill, but it's somewhat tricky to stay on top of that thing. After confirming the treadmill was in fact in perfect working order, I hesitated to proceed in chopping it up for a likely failed project. But what the hell else am I gonna do with a treadmill?
Chopping Block
Next step was to figure out how to make the track as close to the ground as possible so that it had its best chance at propelling the treadmillmobile. As it stood, the track rode about 6" from the floor due to the motor housing and all that crap. Well that's not going to work because the bottom of the track ain't no where near the ground. But, since this treadmill was able to 'fold-up' for storage, I was able to rotate the motor housing and controls mostly out of the way of the top side of the track. With a potential solution to the debacle, I began to chop off all that unnecessary crap like track guards and everything else that keeps the moving parts from being exposed during normal operation. Next, I detached the wiring harness from the control panel and pulled the wires down through the handles. Then I chopped off the frame and handles with the angle grinder and ground it down as close to the track pass line as possible.
Reassembly
I carved up some of the plastic paneling I had removed to cover up the exposed motor and motor controller electronics to protect them from things like snow and the hands of little kids. I rewired up the control panel and zip tied up all the loose and hanging excess wiring from the distillation of the treadmill. The treadmill manufacturer did such a good job of warning picures like 'no babies on treadmill' and 'don't fall off' I decided to cut out the warnings from the scraps and glue them to the treadmillmobile.
Wooden Base and Power Seat
Well if I'm gonna ride this thing I need a friggin' seat. I cut out a baseboard of 1/2" plywood (raided from the construction dumpster down the street) and some angle iron (found in the creek) for supports. This particular treadmill has an 'incline' feature that allows the user to make the running more difficult by increasing the angle of the treadmill. The incline feature used a reversable AC motor, gearhead, rack and pinion and cam. I though for a while to come up with a way to use this device to steer the treadmillmobile with no success. So I decided to convert the incline feature to an adjustable power seat back. I think this is a nice feature. Might as well be comforatable before taking the ride of death.
Modifying the Track Path
With as much material chopped off as possible, the track still did not extend beyond the drive motor secondary pulley. After some thoughts of increasing the track thickness with glue and wood planks to enable it to clear the motor pulley, Pinkston came up with the idea of putting idler rollers between the frame and track to push the track down further. So I ordered 6 sets of nylon rollers assembled on aluminum channel for $3/Ea from the surplus center to do the job. These rollers basically just ram the belt down past the rest of the frame by about 1.5". I used 3 sets of rollers on each side of the treadmillmobile.
Test Drive
Ok, here it is. All construction is complete and all systems are in working order. Two horses under the hood, power seat adjusted, no way to steer or stop, and a 100 ft orange extension cord hanging out the ass end back to the garage. Well as it turns out there is really no need to turn or stop, because the treadmillmobile can hardy take off by itself, let alone with someone on board. With the belt tension required to keep the main drive roller from slipping (with me on board); there is so much friction induced on the system that the power controller craps out on 'current limit' at about 1000W. So either I need to find a way to employ a nip roller to grip the track without putting craploads of excess friction on the rest of the system or I need to build a better power controller. Overall I would grade the success of this project with F for friggin' garbage, but the power seat gets an A.Sissy-Girl Power Controller
The sissy-girl power controller I'll call SG for short is seriously insufficient for this ride. Max DC output voltage was 85Volts, max current about 11amps. Waveforms of no load and 'current limit' loads below.
Future Upgrades for the Treadmillmobile
-a way to steer around obstacles like cars would be nice-Headlights-so I cars can see me a comin'
-an air horn-so old ladies can clear out of the sidewalks I'm racing on
-on board gasoline backed AC power generator
DISCLAIMER
The author assumes no liability for any incidental, consequential or other liability from the use of this information. All risks and damages, incidental or otherwise arising from the use or misuse of the information contained herein are entirely the responsibility of the user, have a nice day!
Last updated: 01/13/08
Copyright 2007, Greg Miller
https://www.angelfire.com/80s/sixmhz/treadmillmobile.html