What part do i need

[boyardee12]

Well im new at this and i am building a robot for this competition and i need to lift a box that weighs around 5lbs and i was think of making a forklif but i don't know what i need to make it go up

 so like do i need a chain (to make the platform that the item will go on rise up and down) or do i need something like tracks and i need some kind of motor to right?

[airman00]

any website or something?


All you need is a motorized lever , like a seesaw (except motorized)

Forklift requires a rack and pinion gears

[Trumpkin]

yep you do need a motor don't use a servo unless you wanna spend big $. i would not do a forklift (very complicated). if I were you i would use windshield wiper motors because they have reasonable torque and are cheap. here is a CAD of my arm design

[airman00]

windshield wiper motors are over kill 

just look for motors with the torque you need , there are PLENTY out there for cheap

[Trumpkin]

windshield wiper motors are over kill

5 lb box is pretty hefty. and you can get windshield wiper motors at surplus stores with no shipping costs. although it may be hard to get a big enough battery, you would have to use lead acid batteries.

[boyardee12]

so are these  lhttp://www.vexlabs.com/vex-robotics-advanced-gear-kit.shtml  Rack and pinion pack seem right? I cant seem to  find them anywhere else cheaper.

[airman00]

so are these  lhttp://www.vexlabs.com/vex-robotics-advanced-gear-kit.shtml  Rack and pinion pack seem right? I cant seem to  find them anywhere else cheaper.

lego also has

I built a forklift once with my friend's lego mindstorms a year ago

but ed1380 said soemwhere else that forklifts use a piston ( though rack and pinion works as well)

[boyardee12]

o yea does anyone has a diagram or something of how a fork lift works? I already tried google but didn't find none.

Also im not sure if i can get underneath the box to lift it up so i was thinking instead of a platform/forks i could something like a gripper. However the thing is the box im picking up is 30x30x30 cm is also the box the robot has to fit in at the begining. there for i would have to make it contract then expand. Do you guys think that this is overdo?

[airman00]

o yea does anyone has a diagram or something of how a fork lift works? I already tried google but didn't find none.

Also im not sure if i can get underneath the box to lift it up so i was thinking instead of a platform/forks i could something like a gripper. However the thing is the box im picking up is 30x30x30 cm is also the box the robot has to fit in at the begining. there for i would have to make it contract then expand. Do you guys think that this is overdo?

why not have a bar on a fulcrum , kinda like a catapult that goes up slowly. Pick up the box that way

[boyardee12]

can you elaborate on that idea more?

And sorry i forgot to post some details the box doesn't have a top or bottom so it not really a box. Also i need to pick this "box" up and put it over items.

[airman00]

Bottom part slides under box . Motor turns the lever at the fulcrum point( so you don't need a downwards force)

[Admin]

o yea does anyone has a diagram or something of how a fork lift works? I already tried google but didn't find none.

you didn't try very hard . . . very first result for 'forklift' says hydraulics . . .
http://images.google.com/images?sourceid=navclient&ie=UTF-8&rls=DGUS,DGUS:2006-11,DGUS:en&q=forklift&um=1&sa=N&tab=wi

why not do a pulley system, and just wrap the string around the motor shaft?

[boyardee12]

I can't use hydraulics system but i was asking for a more internal diagram since im a beginner  anyways im actually not in need of of one anymore i got a different design

[paulstreats]

Why not attach a long bolt to a motor/servo output shaft and have a nut slide up and down it when it turns?  if the linear parts are connected to the nut, this will also move up and down.