Flipper components

[jamesb]

you would need the following:-
a car tyre compressor - £5 from any good car supplies shop like motormania.

a buffertank - eg. a coke bottle, or a coil of pneumatic pipe. Whipper used pipe to great effect.

a valve - available lots of places, including me.

a ram, same as above.
pressure switches.... not really needed if you do it right.

the system can be done for as little as £30.
e-mail me if you need more info, and ill let you know what i have in stock.

Ill have a think about Ewans suggestion of writing a guide unless someone has already done one.

e-mail me (profile) Im a CNC machinist and make hyrdrulic fittings in 316 stainless and high nickel alloys.

cheers
kenny

[jamesb]

eh? when did that happen?

Ok on my profile is a basic diagram that I used in Turbine 3 (and now used by Mini Hurts)

The diagram shows a standard compressor setup working with a 5/2 valve to fire and retract the ram. However a 3/2 valve could be used in place for single action.

I WOULD strongly suggest the use of a pressure switch. Wire up your compressor so when you plug in your removable link your compressor activates. Then set your pressure switch to a desirable pressure (such as 10bar) the pressure is usually settable via a small screw on the top of the pressure switch. When the pressure has built up in your buffer tank and pipe work the pressure switch will turn off your compressor automatically via a relay (the Pressure switch does not have the strength to do this on its own, so the use of a relay will stop the switch burning out). The point in this is so you don€™t have to be constantly thinking about topping up your pressure during a battle, it can all be done automatically.

For a buffer tank I would suggest a Blow torch butane tank, as these bottles have been easily tried and tested up to 18bar by myself and weight very little. For the adaptor for the buffer you can strip down the plastic blowtorch handle and inside you will find a machined piece of aluminium. Un-screw the blow torch end and you should have a 1/8th BSP hole, witch you can put standard fittings into (available from http://www.technobots.co.ukwww.technobots.co.uk)
As for the butane in the tank, before you take the handle apart just use it as a standard blowtorch and let the gas burn off. (Its the safest and most environmentally friendly method When you are SURE all the gas has gone put a drill bit through the one way valve in the top of the butane tank. This is so that you can easily pass gas into and out of the butane bottle for use as a buffer in your robot. Screw the machined aluminium handle back on with a 1/8th BSPx6mm(or whatever size pipe your using) T stud. The 2 pipes coming from the T stud can now go, A) to your compressor and B) to your valve.

Then as you probably know the pipe or pipes from your valve can go to your ram. (A Q.E.V from http://www.technobots.co.ukwww.technobots.co.uk will speed up the extension time of your ram allot)

I would suggest an electronise 2way relay to fire your valve. Or if you can€™t afford that I glued a micro switch to a servo for a short while. Witch worked just as well, but you will get a small delay between your T/X and the actual firing of your valve.

I hope this helps someone. If you have any more questions regarding compressor powered pneumatics send me an e-mail.

Sorry I can€™t supply an accurate wiring diagram of the relays and switch etc, it€™s been a long time since I built Turbine 3

[geoff]

David,
Before you get carried away with your buffer tank idea please read below...Especialy 8.3, 8.4 & 8.6.. Are you sure what you are planning can comply?

Geoff.

Extract from FRA build rules (29/11/05)
8.1.
Pneumatic systems should use one of the following gases: Carbon Dioxide [CO2] , Air, Argon [Ar] or Nitrogen [N2]. Other inert gases may be used but consult with event organisers for acceptability first. (The only gas routinely available from organizers of U.K. events for refilling purposes is CO2).
8.2.
The maximum pressure at any point within a pneumatics system shall not exceed 1000 psi (68 bar).
8.3.
The compressed gas shall be stored in a commercially manufactured gas cylinder of appropriate design, specification and certification. Except where the maximum storage pressure is less than 50 psi (3.4 bar). N.B. Some events may have further restrictions on bottle sizes/weights used please contact the event organiser for clarification
8.4.
The gas cylinder must incorporate a burst disc or pressure relief valve with a relieving pressure of 190 bar. Exemptions from this requirement are where the manufacturer or manufacturers agent fills the gas cylinder and applies an integrity seal / wrapping, or the storage pressure is less than 50 psi (3.4 bar). Event organisers may wish to check integrity seals prior to their use.
8.5.
Gas cylinders charged to pressures of greater than 50 psi must incorporate an isolation valve that can be operated from outside of the robot.
8.6.
Gas cylinders that do not incorporate a valve (for example: the gas is released as soon as the cylinder is screwed into it€™s mating pneumatic connection) such as found on disposable welding bottles and €˜fizzy drinks€™ machines must have an additional remote isolation valve accessible from outside the robot.

Geoff. These rules apply only to the storage bottles, not the buffertanks.

The buffertanks will not be charged outside the arena.
Also, the PRD mandatory in any pneumatic system will make sure the buffertanks, valves and rams are not pressurised above their rated working pressure.

Otherwise the system is not allowed.

8.1 = The bottle WAS storing butane, But the Butane would be removed to store the compressed air from the compressor.

8.2= impossible to get a compressor strong enough to go over 1000psi in a feather.

8.3= Myself and DTK used similar bottles no prob on 10bar (think DTK ran 16bar infact)

8.4= Its 10bar = 140psi. However I agree YES a 11bar PRV should be used. Also i dont believe a buffer tank has ever been required to have a Burst disc, Reseviours only i believe.

8.5= Dump valve, goes without saying.

8.6= please explain the need of an isolation valve for a LP buffer tank.

[jamesb]

from my point of view, having made only about 10 of these, the cheapest way to make a nice flipper is.....

£5 compressor. these get to anywhere between 100psi and 150psi before the pressure causes heat backup and the compressor cannot go any further with the pressure. it is in effect self regulating, crude, but it works.

to save more cost, trial and error at home with small diameter holes will limit pressure further, aim for 50psi to avoid the need for prds, although event organizers have been known to allow compressors without prds

pipe buffertank, a long coil of the pipe going to the ram acts as a buffertank, and is light, cheap and very effecive, as proven by whipper.

valve, a single acting valve is fine, easily picked up for £10, and will flow enough gas to make a nice flipper.

a cheap plastic ram from the £1 shop is a large diameter, long stroke solution, but having tested them dont go higher than 50psi. you have a ram alex, so no worries.

finally, bungee return, dont need an exhuaust valve if you have a leaky ram (like to £1 shop one) or drill a 1mm hole in the ram.

cheap, easy, and SAFE!!!

e-mail me for info, i have most of this in stock, and beware overly expensive advise. A lot of money is wasted in this sport following other people, when there are better/cheaper/simpler/safer ways of doing things.

oeps, double

(Message edited by maddox on February 26, 2006)

and if i posted half the grief i get from people on msn for giving advice, this thread would be twice the size. Dont know why i bother half the time.

Just a reminder, if you dont have 10 years engineering experience, 5 years practical fighting robot experience, 9 GCSEs, & alevels, an HNC in health and safety, with NEBOSH certification, a degree in mechanical engineering, nearly 200 satified customers with over 50 machines built, a 100% safety record, £1,000,000 personal liability insurance against accidents, bad service, and advice, (and a lot more common sense than many of the people I know,) then please sit back down and dont snap at me on msn then log off so i cant reply.

end of rant.