Building a feather hammer, seeking inspiration

[daveimi]

There are the usual suspects, little hitter, no toy etc, can you think of any more I can ponder at to get an idea of how they go together? I already have most of it planned just interested to see how others have done it.

[Mega Masher]

How about that new one being built by robochallenge

[daveimi]

oh cool not seen that yet!

[Revsmin]

It depends whether you're looking to use an electric motor or pneumatics. LH3 & Basher use pneumatics, No Toy, Onyx & RoboChallenge's build use electric motors.

[RogueTwoRobots]

There's a collection of photos of Onyx during the build on my Photobucket: http://s31.photobucket.com/user/ayrs...?sort=3&page=1

Quite a few pictures of the axe mechanism with one of the bulkheads removed showing how it's set up. Essentially it's just an electric motor with a 9-tooth sprocket on it (for both the drill motor and scooter motor) running through a chain to a 45-tooth sprocket on the axe.

There's a 12mm shaft that goes through the bulkheads. This is a live shaft (meaning it rotates when the axe rotates) and there are 12mm needle roller bearings pressed into the bulkheads. The 45-tooth sprocket is held onto the shaft with two M5 grub screws at a 90° angle and it has two M10 bolts going through it that bolt on to the axe arm.

So motor turns the chain which turns the 45-tooth sprocket which is directly connected to the axe and wham

Still got a few kinks to iron out (partly with the weapon, mostly with the robot/chassis) but when it works it works well. It's the simplest way to do it, especially compared to Grant's high quality cam-based version, and it doesn't cost a huge amount either. The scooter motor is about £40, and all the chain and sprockets, bearings, shaft and bolts can be bought from Technobots for not too much either.

[daveimi]

Thats so awesome thank you will have a look at all the pictures!! Reaching that point where I'm bored of building drill powered pushers and fancy something a bit scarier. I suppose it's all part of the evolution of being a robot builder. Thank you for steering me in the right direction. Are the sprockets and chains etc available on technobots and so on?

[daveimi]

Sorry I meant to ask does your robot hammer have enough torque to self right? And is that a 300W ish scooter motor?

Have you seen Mangi from the states?

[adz600]

Even much lower powered motors for the axe will self right, No toy uses mfa 48/50w axe motors they are 700 size high torque low revs, it will fire the axe on one motor but not self right , I use twin motors for reliability and reduced stress on parts, I also run the motors undervolted in no toy due to the controller but when tested on 22.2v it was amazingly powerful but the wheel drive motors couldn't take the strain. Don't be to narrow minded on motor options but as Jamie says scooter motors work great and can be found for just over £20 , if using scooter motors I would also just use there sprockets and chain assembly also just for ease of building. good luck but one tip here start low on voltage and work up if not you can cause major damage to the chassis or drives before you have even really used it. adam

[adz600]

http://s1323.photobucket.com/user/ad...d39f1.mp4.html

6s lipo test

[daveimi]

That's really cool Had a look on ebay and you can get the chains, sprockets and motors and stuff on ebay from lecky scooters. When you're putting the chains together do you just use a chain splitter and so on?

I will start at sort of 12V and work up probably.

[Mega Masher]

Sorry to go off topic here, but, jamie, are you bringing onyx to the champs?
Yep, you use a chain splitter. It was in someones build diary about a week ago I think