robot grabbing a can. where to find rack gears?

[SpEdwin]

im kinda running out of ideas on how to approach this. basically my meccano robot has a forklift and i was going to attach a claw on it at the front to grab a can off the ground. the problem is the claws i find online are either to small or too big. (too big because the robot will learn forward from vex robotics, too small that it wont be able to grab the can from sparkfun's mk2 claw). so i thought of trying to make my own mechanism to grab the can and i came across this http://www.youtube.com/watch?v=mJaHWXf5ks0 but i have no idea where i can find rack gears of reasonable size. i dont want to pay a considerable amount just for shipping from america just to get rack gears as well :'( 

any ideas on how to approach?? or where i could find rack gears?? 

[Kris]

I'm poetry sure you can make them at the space with laser cutter.
(hand waves) shouldn't be too hard.
Not sure how durable they would be though

SpEdwin <edwin...@gmail.com> wrote:

im kinda running out of ideas on how to approach this. basically my meccano robot has a forklift and i was going to attach a claw on it at the front to grab a can off the ground. the problem is the claws i find online are either to small or too big. (too big because the robot will learn forward from vex robotics, too small that it wont be able to grab the can from sparkfun's mk2 claw). so i thought of trying to make my own mechanism to grab the can and i came across this http://www.youtube.com/watch?v=mJaHWXf5ks0 but i have no idea where i can find rack gears of reasonable size. i dont want to pay a considerable amount just for shipping from america just to get rack gears as well :'( 

any ideas on how to approach?? or where i could find rack gears?? 

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[Matt Joyce]

There was a pretty simple grab in a recent post a about homebrew projects in China.

Was a simple worm screw and a handful of gears.  Struck me as a 3d printable approach.

M

On 12 May 2013 13:51, "SpEdwin" <edwin...@gmail.com> wrote:

im kinda running out of ideas on how to approach this. basically my meccano robot has a forklift and i was going to attach a claw on it at the front to grab a can off the ground. the problem is the claws i find online are either to small or too big. (too big because the robot will learn forward from vex robotics, too small that it wont be able to grab the can from sparkfun's mk2 claw). so i thought of trying to make my own mechanism to grab the can and i came across this http://www.youtube.com/watch?v=mJaHWXf5ks0 but i have no idea where i can find rack gears of reasonable size. i dont want to pay a considerable amount just for shipping from america just to get rack gears as well :'( 

any ideas on how to approach?? or where i could find rack gears?? 

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[Ada Lim]

On Sun, May 12, 2013 at 1:51 PM, SpEdwin <edwin...@gmail.com> wrote:

any ideas on how to approach?? or where i could find rack gears?? 

What gear will it be mating with?

(for that robot, I'd lasercut.)

 

[Edwin Guo]

i have no experience in cad drawings so im not sure about the 3D print approach. but i might try find premade sketches and print it out as an option  

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[Edwin Guo]

that depends on the rack gear if i find one. worst case i can always find lego pieces. hahahaha 

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[ada]

On May 12, 2:58 pm, Edwin Guo <edwin.g...@gmail.com> wrote:
> i have no experience in cad drawings so im not sure about the 3D print
> approach. but i might try find premade sketches and print it out as an
> option

find the pressure angle of the gear that you're mating with.
find the tooth pitch / module.

draw little trapezoids of the appropriate size.

project them.

see http://www.cage-gear.com/spur_gear_calculations-1.htm

if you're really stuck i can whip up some openscad. but i suggest
that you try it first; if you can program you can make these.