Team Bodge Job

[Bodge Job]

This is my new topic/diary thing, as the old one was filled with rubbish.

I haven't really done any work in a while, and as i cant make any of the major events this year im going to slowly work though upgrades, and all the little things I want to do to it that I think would help.

I have given up on Bruiser 2, as to much is wrong with it, after rushing it for the camps. So I have started work on Bruiser (1).

I am planing to fit an electric axe/hammer to bruiser which should sit on the top nicely, and be removable, for when it gets smashed to pieces. At first I will be using a gimpson motor, and 4:1 reduction though chain (stolen from the rotting remains of bruiser 2) but I may change that to 1 or 2 speed 900 size motors with 2 stage reduction, depending on weight and its effectiveness.

The second main upgrade is the drive, I will be improving the mounts to hopefully reduce how often the gear boxes break, The gear ration will be changed from 36:1 to 24:1, to increase the speed, along with the battery being changed from a 12 volt lead acid, to an 18 volt LiPo or NiMh, this will obviously increase the speed further, and increase the amount of current available to the robot, so it should have slightly better acceleration, and pushing power. This theoretically should increase speed by 225%, which should mean the robot can go a new top speed of 11mph (with an allowence for losses) which should make the robot more competitive.

Other upgrades will include wheel protection from and back, and a shampfered back top edge, so it can drive when on the axe mounts, and improved electronics.



[attachment=1:3rf9hbrh]Photo0236.jpg[/attachment:3rf9hbrh]


[attachment=0:3rf9hbrh]Photo0238.jpg[/attachment:3rf9hbrh]

[Bodge Job]

little to no work on the bot, just tested the robot on a 24:1 gear ratio as the last one broke at 36:1, but that broke too! may change it to 2 speed 900 size motors (stolen from bruiser 2) and use them, but i don't know if they would have enough power to self right at the small 5:1 ratio, what do people think?

here is the video on Ben's build diary, http://www.fightingrobots.co.uk/thre...688#post440688
thanks ben!

[Ellis]

Speed 900 clones at 5:1 would most likely not even move the axe properly (rule of thumb), let alone self right. They definitely have the power, but only after a lot more reduction would you see the sort of power you're getting from the current setup (the 120-180:1 ratios the 550s are running should say it all, you need a lot more than 5:1!)

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Next step, I'd say, is try and either get a normal drill in there or a larger drill. You can have the torque limiter still in place, which should help take up a lot of the stresses. If it is the pins on the gearbox shafts that are coming loose and letting the gears strip then there are quite straight forward solutions to that.

[Bodge Job]

now thats a good idea, i didnt think about the torque limiter on drills, that could work! i think i have a small drill motor free so i could set that up and try that, thanks!

[RogueTwoRobots]

If you want to save a bit on space, just go with the traditional grub-screw fitting on the drill instead of having the whole torque limiter setup in place. You can still have the torque limiting just by screwing the grubs down a little less than what you would for drive. It'll take a bit of trial and error though to find the sweet spot between having enough torque to swing the axe but limited enough to slip once you've hit something.

[Bodge Job]

yeah, thanks, i think it would be best to try it with the torque limiter first, as i think it would be eaiser to test, and get the torque right, but if i have to i will change it to that, i just think it would be good if i could make adjustments without taking the whole thing apart.

thanks though its a good method to fall back on

[Bodge Job]

found the problem with the latest motor damage (ii had presumed it was the gears stripping causing it to spin, but instead it turns out the gear on the motor has come loose). And ive never had this before. The gears are only pushed on like the some of the older drill motors i first bought, rather than the later ones i got which had the flat.

Was wondering if there was a way I could reattach it on well? as if i try another motor i fear the same thing is probably going to happen with the stress of the motor? there appears to be glue one some of the motors gears probably to help with the push fit, but if that wasn't strong enough, how do you think i should attach it?
could attempt to glue again with the torque limiter and see if that prevents it, or could i somehow weld them together?
what do you think as im unsure, or should i just do a few tests?

[Ellis]

If you have any old motors with the flat, use one of those? If not, we have had success with a drive motor by crimping the motor shaft (by which I mean hitting it with something very hard and sharp to misshape it), repressing the gear onto the now slightly distorted (be careful not to bend) shaft, and using a decent two-part metal glue. Can't remember how many fights our fix did, 10 or so, with no problems. :]

[Bodge Job]

yeah problem is its a different gear so doesn't fit the shafts with the flat. i may try welding it first, and then grinding it flat as i think that will be pretty strong (and i dont have any desent two part glue atm) will practive on an old burnt out motor first though and if that fails ill buy some glue.

[plargen]

i guessing you have a tig set if your gonna try welding it