Author Topic: Shoot A Ball From A Tube  (Read 914 times)

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Frogn!pple

• Beginner
• Posts: 3
Shoot A Ball From A Tube
« on: December 23, 2010, 11:41:56 PM »
Greetings all!

I'm new to this area of things and I know what I want, but I don't know the names of anything so it's hard to buy stuff. I'm also open to suggestions.

Basically what I want to do is spring load a heavy (relatively) ball into a plastic tube (PVC) against a plate (or end cap) which is guided via small diameter rod running through the center of the ball. The purpose of this is to load the ball and then shoot it from the PVC barrel. What I need is an obstruction at the end of the barrel such that I can push a button, clearing the obstruction, and the ball will shoot out because of the loaded spring. Sounds like it could be a solenoid or an arrangement thereof that serves as the obstruction. I also need to know a simple way to trigger the release of the ball remotely. Thank you for your ideas and suggestions.

T0110100101101101K

• Jr. Member
• Posts: 34
Re: Shoot A Ball From A Tube
« Reply #1 on: December 24, 2010, 05:52:31 PM »
It sounds like you do have a basic knowledge of one solution.  A solenoid could be used to create the controlled obstruction.

What are yo trying to build?  To be honest, without sharing more purpose about your project, it sounds risky for someone to want to help out.
A robot could do my job...

Frogn!pple

• Beginner
• Posts: 3
Re: Shoot A Ball From A Tube
« Reply #2 on: December 24, 2010, 11:39:02 PM »
LoL. If I were making an item purposed for hurting someone, I think advertising it on the internet would be a mistake. I want to make a really neat top. Normally when you spin it it goes soley based on how hard you spin it. What intend to do is make use of manipulating the item's moment of inertia. Moment of inertia equals radius squared multiplied by its mass and a contant based on the shape. The top will start out with a relatively large moment of inertia, and then shift to a smaller one when the mass shoots towards the center of the item. Once its moment of inertia has decreased, because the momentum is conserved, its speed must increase- so the top will spin even faster. Best part is that the speed doesn't increase linearly, but exponentially. Is that what you were looking for?

T0110100101101101K

• Jr. Member
• Posts: 34
Re: Shoot A Ball From A Tube
« Reply #3 on: December 25, 2010, 10:11:45 PM »
Glad to hear nobody will get impaled by a spinning top!

It does sound like a cool project.   I imagine something like a figure-skater.

I think I understand your device description now.  Depending upon the size of the “ball” you are talking about, I believe the specifications of your options could vary significantly.

Again, I can see a solenoid working as a frontal obstruction, but what do you imagine will work to compress the spring and ball behind the obstruction?  Have you considered more of a bow spring design with a trigger release device?

For remote activation, IR will probably work well. I bet you will want to be within line-of-sight to watch the marathon top in action anyway.
A robot could do my job...

Frogn!pple

• Beginner
• Posts: 3
Re: Shoot A Ball From A Tube
« Reply #4 on: December 26, 2010, 12:35:10 AM »
Hmph. I didn't think of that. I like it. I really would appreciate the names of some common components which could achieve this goal, I'm sure whilst browsing the area of those items I'll stumble upon ones of a bigger size or get a different idea. But for right now, I just need to get started. Thanks for the ideas!

walkercreations

• Full Member
• Posts: 90
Re: Shoot A Ball From A Tube
« Reply #5 on: December 26, 2010, 10:14:16 AM »
Depending on your base platform you could make an air powered canon using a paintball gun air canister that would adapt to the application. There are plenty of plans on the internet for making them. They are along the lines of a potato canon. From those plans you could either up or down scale them according to your needs.
« Last Edit: December 26, 2010, 10:16:50 AM by walkercreations »
Peter Walker
Fruitland, MD USA

Soeren

• Supreme Robot
• Posts: 4,672
Re: Shoot A Ball From A Tube
« Reply #6 on: December 27, 2010, 05:38:44 AM »
Hi,

Basically what I want to do is spring load a heavy (relatively) ball into a plastic tube (PVC) against a plate (or end cap) which is guided via small diameter rod running through the center of the ball. The purpose of this is to load the ball and then shoot it from the PVC barrel. What I need is an obstruction at the end of the barrel such that I can push a button, clearing the obstruction, and the ball will shoot out because of the loaded spring. Sounds like it could be a solenoid or an arrangement thereof that serves as the obstruction. I also need to know a simple way to trigger the release of the ball remotely. Thank you for your ideas and suggestions.
I'm not sure I got the whole picture of what you want to do, or how you want to do it while the top is spinning, but you'd find it easier to use a cylinder shape (rather than a sphere), as you can then lock and release with a much less obstruction.
Terms like "relatively" heavy isn't engineering terms and relative measures needs a frame of reference (which you don't provide) anyway, so please add numbers.

For shifting the mass, perhaps look at 3 springloaded arms hinged on the main structure in one end and with weights in their free ends. That would be much easier to "reload" and to engage.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?