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#### Inigo Montoya

• Jr. Member
• Posts: 18
##### Noob advice on forklift mechanism.
« on: October 04, 2012, 03:37:51 PM »
I am a noob building a robot vehicle.  My strengths include excellent design and cad skills (so far mostly limited to home construction).  Moderate level of programming knowledge.  Moderate mechanical and electronic troubleshooting experience.  I am handy around a wrench and know which end of a digital multimeter is which.  I have no specific robotics skills, so this is a grand adventure.

I have built a wooden mock up of my wheels on rail robot, and the rail system.  It resembles a train locomotive, but the rails are on the sides as opposed to below.  I am now in the process of designing the first functioning mechanical prototype, and I seek general mechanical design advice from people who are far more experienced than me.

The question:  I am designing a forklift style mechanism attached to my robot, attached to the robot wheels, for the purpose of raising and lowering the robot.  I have some vague ideas of how to proceed in designing the mechanism which I will share, and I would like input on whether or not this is a good idea, or if there are better, simpler and/or cheaper ways to go about solving this design problem.  I don't want to spend too many resources following a design idea that might not work out.

The specifics:  The robot is a cube 13" on a side.  The rails the robot will drive on sit on either side of it, with 3/4" clearance on either side, and it drives on 2" wheels.  These wheels need to have a vertical range of motion of 11", so that the robot can raise and lower itself much like an Olympic gymnast on parallel bars, thus the forklift style mechanism.  Also, in future builds, the wheels will need to retract so that they can be flush with the shape of the robot, but I save this for a future problem to be solved.  I suspect the robot will weigh at most 4-5 kilos.

The design so far:  I am considering a threaded rod on either side, passing through a horizontal bar that is attached to the wheels.  A continuous rotational servo attached to the frame, and connected to the threaded rods by gears or chain, will rotate the threaded rods to cause the wheel assembly to move up and down.  Is this a good idea?  Is there an easier way I am not seeing because of my nonexistent experience in robot mechanics, or should I continue in this direction?

Any input would be very valuable to me.

Thanks a lot!
Inigo