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Nick
Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
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Have a look at the refills for Paslode and similar nail guns. they are part-way between the size of a soda bulb and a refill tank and are designed for a secure coupling and workplace abuse.
To make a project like this work quickly, using at least some of an original nail gun makes sense, like the gas tank, regulator, valve, igniter, etc.
I would be worried about the possibly higher pressures developed from driving an assembly with way more inertia. Beefing up the cyclinder, piston and seals makes sense, as does a pressure release valve for when the lifter gets stuck. You might also need a silencer on the exhaust port...
Having a lifter or flipper that has a few hundred shots between refills would be way cool - best of luck with the project.
_________________
Australian 2015 Featherweight champion
UK 2016 Gladiator champion
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Fri Aug 06, 2004 12:58 pm |
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DavidM
Joined: 07 Jul 2004
Posts: 41
Location: Victoria, Australia, Earth, Milky Way Galaxy
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Top speed, never measured it, but about jogging pace, faster than walking but you could sprint faster. Riding it, the speed was comfortable, of course if it was faster that would be an advantage. I used to ride it through the office, a top speed it was an accident waiting to happen.
How did it feel, on the good side the speed control with the friction drive was good, even in the rain (a bit of slippage). The steering could have been better, using a scotch T-hinge achieved a quick and inexpensive build, but most people found it a bit difficult until the scooter was going - mind you once you have used it a couple of times your balance improves and starts are not a problem.
One thing the picture doesn't really show is with the removal of a bolt at the steering hinge the handle bars fold down/back - this is essential for stowing it and moving it around in say the boot of a car. A complete accident in design but a goodie.
Issues with the scooter:
It used hard wheels that are cross sectionally flattened. I could 'round' the cross section off on a lathe but never got around to it. It was like having car tires on a motorcycle. Bad for leaning into corners.
Inflatable tires were available but not for the diameter I used which was determined for the friction drive ratio, so larger diameter tires would have limited the speed unless the drive wheel was increased, at the time my goal was two weekends for the build, so hard tires with bearings it was.
No suspension, a little hard, especially where I lived at the time, the tram tracks! ______/\_______/\______ if you know what I mean.
Battery/range etc.. The 17.5 Ah I didn't actually own (why it doesn't have one today), so I made sure I didn't discharge them too far. A conservative guess a couple of kilometers flat, better with boost/coast driving. Never went further than about a kilometer myself.
Brakes, it didn't have any, Spockie mentioned regen braking which is a good idea, because of the friction drive nature you could vary the braking by pressure on the pedal. But a bike brake or similar is really needed to stop in a hurry, regen will only slow you down.
Wiring keep it short - the battery to motor wiring was only 20 cm or so, I used a relay to switch the power, and really heavy cable (with a 17.5 Ah battery the Vdrop on the wiring can be quite large and limits the max speed). I used a button on the handle bars to switch the motor on and off, alternatively a microswitch on the pedal would have been a better idea, just switching the motor on before the friction drive wheel comes in contact with the rear wheel.
The motor got warm but not excessively hot.
Regardless it was fun to scoot around on, having the lights and blinkers were useful in the area where I lived and gave it a bit of character.
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"Limitation shows the Master."
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Mon Aug 30, 2004 1:10 pm |
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