Author Topic: Moving rod  (Read 2033 times)

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aukirko

• Beginner
• Posts: 5
Moving rod
« on: June 06, 2010, 04:57:39 PM »
I want to make a rod move back and forth horizontally. I want to keep it as simple as possible also. I have absolutely no clue how to achieve this. I have only been able to find things about everything spinning not having something move in a specific direction. I want to activate the movement just using a switch.

Here is an image I made in MSPaint real quick to kind of show what I want.
http://img688.imageshack.us/f/electricarm.jpg/

waltr

• Supreme Robot
• Posts: 1,944
Re: Moving rod
« Reply #1 on: June 06, 2010, 05:06:53 PM »
What diameter?
How long?
How far does it need to move?
How fast does it need to move?
Can the rod rotate as it moves linearly or not?
Is there any force, resistance to the motion?

aukirko

• Beginner
• Posts: 5
Re: Moving rod
« Reply #2 on: June 06, 2010, 05:47:39 PM »
What diameter?
How long?
How far does it need to move?
How fast does it need to move?
Can the rod rotate as it moves linearly or not?
Is there any force, resistance to the motion?

Sorry I have no idea where my tape measure is.

The diameter of the rod is about a quarter of an inch. And 3in long. Weight is about 33g.

Needs to move 1.25in

I want to move back and forth about 15 times per second.

Can not rotate as it moves linearly.

It needs to hit and open valve that has about a 10 or 15lb spring.

vinito

• Full Member
• Posts: 101
Re: Moving rod
« Reply #3 on: June 06, 2010, 05:57:34 PM »
for 15 cps, I'd make that rod operate as a plunger in a solenoid.
You could either buy or scavenge one (out of an old pinball machine, doorbell or dozens of other things), or if you did the math you could wind your own. It's just a simple spool of wire - the tricky thing would be figuring out the number of winds for the wire gage and voltage you want it to operate at.

Anyway, it would just slide to one side when voltage was applied, then a spring would slip it back to "rest" position.
Layman's terms. I'm no expert.

aukirko

• Beginner
• Posts: 5
Re: Moving rod
« Reply #4 on: June 06, 2010, 06:15:52 PM »
Yeah I have a sleeve/cylinder for the rod already. The rod also has orings on it that I lube to help it slide. Just need to get it down and back some how. I thought of using another spring to get it back to the position.. but still not sure how to get it down it using a switch.
« Last Edit: June 06, 2010, 06:18:25 PM by aukirko »

vinito

• Full Member
• Posts: 101
Re: Moving rod
« Reply #5 on: June 06, 2010, 07:14:16 PM »
Alternatively, rather than making your rod into a solenoid you could buy one which has enough travel for your application and just push your rod with the solenoid plunger. That would probably be cake.

aukirko

• Beginner
• Posts: 5
Re: Moving rod
« Reply #6 on: June 06, 2010, 07:36:38 PM »
You have a link to anything that would help me out with making it into a solenoid? Or have an example of something so I can figure how to rig it together. Not sure how I would get a plunger to make it work.

waltr

• Supreme Robot
• Posts: 1,944
Re: Moving rod
« Reply #7 on: June 06, 2010, 08:05:24 PM »
For a periodic motion I'm thinking of a crank wheel and connecting rod, reverse of a steam engine. Drive the wheel with a gear motor and the connecting rod moves the plunger rod.
A cam may also work.

Soeren

• Supreme Robot
• Posts: 4,672
Re: Moving rod
« Reply #8 on: June 06, 2010, 09:17:50 PM »
Hi,

Needs to move 1.25in

I want to move back and forth about 15 times per second.

It needs to hit and open valve that has about a 10 or 15lb spring.
This equates to 900 RPM and assuming a distance from center of a rotating "wheel" of 5/8" it will need a torque of at least 154 ozf-in (if I didn't screw up on the math).
If it is possible to change the spring to a softer one, you can make do with a less powerfull motor.

If this is for a paint ball gun (?), you need to consider how much runtime you need and how large a battery you wanna drag around.

If you describe the actual purpose, perhaps some other (less power hungry) means could perhaps be found, but it's difficult without that knowledge.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Engineering is based on numbers - not adjectives

aukirko

• Beginner
• Posts: 5
Re: Moving rod
« Reply #9 on: June 10, 2010, 10:57:56 PM »
Hi,

Needs to move 1.25in

I want to move back and forth about 15 times per second.

It needs to hit and open valve that has about a 10 or 15lb spring.
This equates to 900 RPM and assuming a distance from center of a rotating "wheel" of 5/8" it will need a torque of at least 154 ozf-in (if I didn't screw up on the math).
If it is possible to change the spring to a softer one, you can make do with a less powerfull motor.

If this is for a paint ball gun (?), you need to consider how much runtime you need and how large a battery you wanna drag around.

If you describe the actual purpose, perhaps some other (less power hungry) means could perhaps be found, but it's difficult without that knowledge.

Yes it is for a paintball gun. Right now, I just want to get it functional, then I can worry about the rest of it later.
« Last Edit: June 10, 2010, 11:03:45 PM by aukirko »

little-c

• Robot Overlord
• Posts: 186
Re: Moving rod
« Reply #10 on: June 11, 2010, 03:04:08 AM »
internal combustion engine or steam trains have a mecanical method of converting horizontal motion to rotational motion. just switch where the power is applied. look for a diagram on google images.

one alternative. might be cheeper/less power hungry.

Gertlex

• Supreme Robot
• Posts: 761
• Nuclear Engineer · Roboticist
Re: Moving rod
« Reply #11 on: June 28, 2010, 07:21:09 PM »
Ok, so this doesn't fit "simple," but it is a fun mechanism:  Peaucellier Cell

http://en.wikipedia.org/wiki/Peaucellier_cell

Also requires that the motor rotate back and forth over and over.  So it might be a major challenge to get the speed you want with anything but best hardware....
I

• Full Member
• Posts: 64