double postin time!

i layed out some things on paper and did a few sketches and knocked up some quick cads of it here.

http://photobucket.com/albums/v357/Cobrarobotics/Beta%20Max/?action=view&current=pinchy.jpg

3mm aluminium linkages, 5mm jaws, 10mm poly drill mounts 8mm diameter jaw pivots drilled out to 4mm. jaws should open up to 160mm fully opened and close all the way to shut. i figure it should weigh dead on 1kg not including the frame. so thats abit worrying, yet amazing that the drill and stuff could fit into that much weight.

im looking at changing the motor over to a smaller 6v jaycar one and really considering getting rid of the gearbox case all toghether and sanwhiching the ring gear in between the two lexan plates.. that should ditch alot of weight.

now ill try give you a bit of a randown as to how it works. basically the two linkages bolt to the jaws and to the bottom of the drill mount. and that little jack is bolted to the back of the robot.. the drill itself moves back and foward pulling and pushing the jaws shut. i cant concieve a lighter way to do the crushing mechanism, so ill work from there

as for the frame, nfi, theres about 1lb to do that in according to the weight table, so thats going to be a great challenge indeed.

if i shoved a brushless in there, some maxons and a lipoly i reckon that would be one awesome teeny bot.
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Glen the trouble with mounting the ring gear in some poly will be that you still some how need to suport the shaft bush and also the thrust bearing on the front inles you can replace it with a ball bearing but the smalests non specialised bearig i have found that fits that shaft size would add heaps more weight than the gear box and bush ..you wil also need bolts or something to hold the poly together ina sandwich fashion so that will add weight also ...

the designs got some rod holding the two poly pieces together included now so thats not a problem, i was thinking i might be able to cut down that big long bush thats in the D part of the gearbox at the end and press that into the poly?
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many many things to say now so stay put lol...

i sat down till almost 3am playing around with the design to get some good weight savings and effectiveness into it and heres how its changed.

the drill actuator ive pretty well got worked out. here it is as it stands -

http://photobucket.com/albums/v357/Cobrarobotics/Beta%20Max/?action=view&current=DSC01878.jpg

what the plan is, is that ill remake a custom motor mount out of 6mm polycarb. there will also be another 10mm polycarb plate ahead of the ring gear, with 4 bolts passing through the two plates to clamp it all together. ill cut down the bushing and press it into the front mount too, and the thrust bearing will be bored into the 10mm im pretty sure of. i want to lathe off the majority of the shaft to 8mm and put the threaded rod all the way down the shaft so its much shorter.

the actuator now goes the other way around so the shaft sticks out the front of the claws. there will be a spike ground onto the end of the shaft too so hopefully some impaling action will go on the little jack will also pull the jaws shut with the linkages bolted inside the pivot this time (its outside in the last cad). should be way more robust. its much smaller at least.

not sure how size is with the other beetleweights (c'mon tell me now ) but the jaws open to 200mm and shut to 0mm as well as pulling inwards (into the spike as luck would have it).

with the insanely cut down drill and what not the total weight is 1kg almost on the dot. leaving about 350g to go for a frame, thatll be an interesting endeavour. fibreglass is looking good for it tho. but the weight of the drill includes the 250g motor, the 6v one should be about 200g
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

plenty of little robot work.

that gearbox needed making. i think if it works it would make a kickass addition to a featherweights drive as it really cuts down the length a lot and also makes them far lighter.

but heres how it goes now with the two 6mm plates. kinda looks like the whyachi ones . theres going to be 4x m3 bolts that pass through them and the holes are tapped in one plate so i dont have to waste any weight on nuts and excessive bolt length. also got to get a a spade bit for the bushing and then the thrust bearing from nick and all will be fine.

http://photobucket.com/albums/v357/Cobrarobotics/Beta%20Max/?action=view&current=DSC01880.jpg

that weighs about 300-350g or so with the big drill motor on, so well pleased.
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

got the front plate all ready to drill out for the "crenelations" (is that where there called?) in the ring gear, so the length is about 3mm shorter now and a teeny bit lighter with the holes.

had a thought with all the screwdriver usage... wondering if a cordless screwdrier has the internals the same as the drill? as in can you remove them and the shafts?

thinking the screwdrivers will be much smaller and lighter and have a higher gear ratio for better crushness. and the smaller shafts on them would do me good.
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http://www.youtube.com/user/HyzerGlen - Videoooozzz

i seem to remember the screwdriver gearboxes ring gear is molded into the outta case.

apart from that they are pretty similar

great, reckon i could grab a look at one on the weekend?

might be a really easy way to get alot of the weight out of the robot. i think those are much smaller in diameter too arent they? might let me remove a hell of a lot of weight from the gearbox itself and the mountings and thigns

ecccellent.
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http://www.youtube.com/user/HyzerGlen - Videoooozzz

no worries, I have an already pulled apart one I will bring along.

just to lazy to go find it tonight

lol i hear that, this hot weather totally sucks, in regards to making me want to do stuff...
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http://www.youtube.com/user/HyzerGlen - Videoooozzz

no im just lazy

got the thrust bearing, it couldnt have been designed for it any better... PERFECTION.

got a glimpse of the screwdriver gearbox, exactly the same as a drill but there are more teeth on the ring gear and the main teeth are less tall. seems to be the same diameter. ill stay with the drill for now, not sure about all that plastic.

sisters pilfered the camera so when it gets back i can take some pics
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http://www.youtube.com/user/HyzerGlen - Videoooozzz

couldnt find too many things to do with the robots so the beetleweight got some over unnessecary work lol.

i mated up a 400 size motor onto the gearbox instead of the 9.6v drill motor. saved some size and weight by doing so. i was going to use a 6v motor and over volt it 1.2v but i figure i can only get 10 amps worth of power out of the batteries and the motor can easy draw that being undervolted so this will do fine... and better yet i dont have to spend any money on it

also took some time to press in bushings into the plastic gears, why? because i can

http://photobucket.com/albums/v357/Cobrarobotics/Beta%20Max/?action=view&current=DSC02036.jpg

http://photobucket.com/albums/v357/Cobrarobotics/Beta%20Max/?action=view&current=DSC02039.jpg

weight is around about 350g with the motor. so ive seriously shed some weight from this thing. good good
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http://www.youtube.com/user/HyzerGlen - Videoooozzz

well woke up today and was supposed to go to my brother in laws wedding party or something.... but i got up at like 12 again and they where all gone lol. gotta love them sleep ins.

woodzillas as done as itll get till i get more bolts and cobras scheduled in for monday so i thought id put a little time into the beetleweigt, just so it wasnt totally neglected.

i figured that the crusher motor on the little one is dead weight still. the only thing that could power it with full current would be some full C size nicads. so i de-scaled that down to something more realistic.

drill gearbox complete with p9004 motor awww how cute..



the shaft on the motor is about 1mm smaller in diameter than the inside hole of the gear. so i needed to get a piece of scrap 6mm aluminium, put a 2mm hole in it, pressed that on, then lathed it down to the right size and then the gear pressed on nicely over that. works perfect. also had to remake the face plate of the motor.

i figure if i can get 105kg power from a 200g motor in woodzilla, then this 50g motor can do 25-30kg or so. thatll be plenty for a beetleweight. and i want to make the design more efficient. at the moment in woodzilla the rod gets forced back into the gearbox which aint good. might use cables or some such to pull it the jaw down, will need to put more thought into it.

but the total weight of the gearbox is 250g. down from 550g which is a success in my books
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

http://glen.botclips.net/beetleweights/BM.wmv

just a bit of a flashback there..... i whacked my old videos into one and archieved it... if you like safety and stuff you probably dont want to watch the last part lol seriously.
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz