1st bot

just a rough drawing please

Picture of my home-made actuator on profile. I also use 2 large springs from the motor bracket to the lifting arm either side of the bolts to help it start up easier with a few feathers on the end!

Hope it helps someone

http://images.ibsys.com/2003/1126/2665390_200X150.jpghttp://images.ibsys.com/2003/1126/2665390_200X150.jpg this is probably the best type of jack to use, they are easy to disasemble and the pitch of the thread is pretty good, but its probably better to add a gear reduction in unless your using a window wiper motor, then it will be fine.

ok so is the silver circle the pivot grant on your home made thingy? do you have a pic of the entire construction?

Hi grant , In the pic on y our profile did you just make the entire thing buy yourself or did you dismanlte a car jack ?

Mark- The silver circle on the yellow lifter part is the pivot for the arm, but the silver bit on the motor/thread just joins the thread to the motor via pins and weld on the thread.

Alister-yes i made the whole thing myself, we used the car jack for the wiper motor on the pit as it is a much larger pitched thread and so would not give a large enough reduction on the gold motor and so it would be too fast and not lift enough. i just bought a length of toughned steel threaded bar(M8 although M10 is probably better for other lifters)

So does it work like this-

The motor is fixed down put is allowed to pivot round. As the motor turns, the screw pulls the one side of the pivot down and the motor pivots up?

i think you have the rite idea but not too sure. The back end of the motor mount is held but able to pivot, the lifting arm pivots just above where the thread attatches. and so when the motor screws the thread in, the arm goes up, and the motor pivots slightly from the back.

Ok, Im finally getting around to making my own linear actuator but Im wondering if anyone knows where I can get some hollow tube with walls about 2-3mm thick, and with a tapped 8mm thread down the inside hollow bit, so that a length of threaded rod can fit in it. Is it likely to be available in garden centre/DIY shops or is it something which may have to be custom made?

Many thanks,
Jamie

erm, i cant see that being sold on the shelf so it would most likely have to be custom made. what size thread are you looking at? and how long does the tube need to be?

I see a new job coming up.

Lenny, I can make all you need, as the stuff from a DIY isnt what you can use.

Just email me the plans, and well talk about it trough Email or MSN

using normal threaded bar isnt a good idea, the thread is to fine and will lock up easily.

Thanks for the replies.
Grant: The size of thread Im using is 8mm. The maximum length of the tube would be around 250mm

Alan: I wondered if that might be the case, its just the threaded rod is all Ive got as Im still getting round to buying a car jack thread (moneys currently an issue), plus the normal threaded bar fits into my drill motor driveshafts (I had to tap them because I botched the modification process and ended up cutting off the threaded axle that was already on the drill :))

Mario: Thanks for the offer - itll take me a couple of days to get round to doing some plans, Im tied up with some stuff just now. I dont have/cant work CAD but I could draw them as accurately as possible in Appleworks and save them as a JPEG if this would be ok for a set of plans.

Many thanks,
Lenny

Normaly it would work Lenny, just send it over and discus work.

Lenny
You could go to a scrapyard and get an old car jack, look for a box/square type thread your probably get it for next to nothing or even for nothing especially if you tell them its for building a robot. It will also have the correct size threaded attachment to go up a down the thread. Thats what we ended up using in Rampage.

Ian
Team Rampage

Thanks for that Ian, I might try that now that Im on holiday.

Mario: I sent you an email regarding the custom parts, hope you got it OK, if not let me know, and Ill send it again.

also lenny, if you use normal high tensile thread (which will be perfectly fine if well greased) then you will not need a complely threaded tube. just get someone to weld a tube on the end of a nut as that create less friction and easier to make!

Im planning on building a chassis out of some sort of box section metal and i was wondering if i should use steel hollow square or aluminium hollow square? and what kind of sizes?

Id suggest that you use steel......( and Im basing the sizes on your previous posts stating that your hoping to build a heavy ) ... either box or angle with a 3mm wall.

So box section 25mm x 25mm x 3mm ..... or 50mm x 50mm x 3mm equal angle.

NOT ALUMINIUM for your first attempt at welding!

no this is for a feather (i know im really confusing)

or what about construction entirely from polycarb?

You have 3 choices here:

A monocoque? (spelling please):
Literally meaning 1 shell in old french. Basically the posh term to mounting everything to the armour and base panels. Used often in feathers to improve armour.

A chassis. A frame and supporting structure used to hold everything to and to hold the armour in place. Weightly but has slightly more reliability.

or

a combination of the above.

If youre thinking of using polycarbonate for a shell, I recommend metal panels over the edges. you only have to see terrorhurtzs S5 battle for an answer...

Oh and Woody: Why would he post a heavyweight construction in the featherweight section???

ok peeps id like to get started now on my robot. Im thinking of buying some 6mm polycarb then plating that with metal sheets. How do i work with polycarb i.e. hold it together? I might upgrade to a box steel chassis when i get the funding. I know ewans had some success with this so i was wondering if he could help

If anything mark i would have thought that a steel box chassis would have been cheaper than polycarbonate unless you are getting the poly cheap. nuts and bolts are probably the best way to hold it together.

mark, see http://www.micro-maul.co.uk/micro-maul%281%29.htmlhttp://www.micro-maul.co.uk/micro-maul%281%29.html
you can use thick polycarbonate sheets (of 10mm +) to make a chassis. You just have to tap it together. Dont have any exposed polcarbonate edges though as they will get caught on by a spinner and can shatter.

ok thanks all. I can get upto 6mm polycarbonate cheap but i suppose thats not enough. Anyone know any suppliers apart from plastics plus

Technobots sell loads of polycarb.

I bought a few various panels from Rob Jones. They were various lengths and widths, averaging 400*400 (mm).

http://www.robotstuff.freehomepage.com/catalog.html>http://www.robotstuff.freehomepage.com/catalog.html

Other than that, I could only recommend Technobots. Usual URL.

is the 6mm stuff thick enough?

oh yeah if in doubt double it up and make 12mm

k thanks

bolting it together will be interesting though, i doubt you could tap it being so thin hense u will have to make brackets and bolt it together that way

nvm ill find a way

I think 6mm Polycarbonate is good enough, provided you dont intend on taking on magmotored and astroflight powered spinners.

I dont know about taping it Gary, I aint got round to that bit yet!!!!

as armour its fine, im using it on top of my featherweight. But as a structural material I am not so sure. I have never been a huge fan since I saw what typhoon 2 did to the 30mm of polycarb on the back of hammerhead 2!

Ok well its just if i use polycarb it gets around having to borrow a welder or getting someone to
do it for me. Might stick with steel

why weld?

Was it biohazard that never used a welder? I cant remember but there was some successful american robot that bolted everything together.

Its up to yourself though

I know Biohazard used screws mainly - almost 700 of the suckers...

ok thanks

If your taking on any decent spinner 6mm Steel is a minimum for top end survival or 4mm stainless steel.

Aussie bot Cobra uses 6mm steel and has survived many battles with the Magmotor powered titanium bar spinner Jolt.

If your short on weight 5mm 5083 aluminium with a possible layer of 3mm polycarb should stand up well.