Ideas for a self-tilting mechanism

[Quark62]

TL;DR

Looking for ideas for a mechanism that would enable powered wheels to conform to the contour of an object

Hello,

I would like to ask for ideas for a tilting mechanism for a machine that shoots out odd-shaped objects.

These objects are quite large (about 50-100 kg each), are rolled around on castor wheels, and have slightly different contours.

Here’s a sketch of the machine and the object:

As of now, here is how the machine would work:

Method 1, using a powered tilting mechanism:

1.Prior to the placement of the object, the powered wheels would be tilted to an angle that would fit the contour of the object using some powered mechanism
2.The object will be moved in between the powered wheels.
3.The powered wheels will then rotate and the object will be shot out.
4.After the object leaves, the powered wheels would tilt back to their “neutral” position.
5. The above will be repeated for another object, which could have a slightly different contour.

Method 2, using a self-tilting mechanism:

1.The object will be forced in between the powered wheels. During the process, the powered wheels would automatically tilt to conform to the surface of the object, with the help of a "self-tilting" mechanism.
2.The object will then be shot out
3.After the object leaves, the powered wheels would tilt back to their “neutral” position.
4. The above will be repeated for another object, which could have a slightly different contour.

I expect the angle of tilt of the wheels to be small, at about +/- 1.5 deg from their “neutral” position.

Let me know if you have ideas for the tilting mechanism for either method!

 

[DaveC426913]

I'd like a little more detail on this before trying to give an intelligent response:

What are all these odd-shaped objects? How different are they?
Where are they being shot out to? Anywhere?
How much do they mass?Here is a suggestion for a solution:
What if the traction wheels were on the bottom? All your odd-shaped objects presumably have a bottom.

 

[Baluncore]

Use a round section like a motorcycle tyre.
Use low pressure with a large soft contact patch.

 

[berkeman]

Welcome to PhysicsForums.

machine that shoots out odd-shaped objects

100 kg each

That's a pretty heavy object to be "shooting out". What acceleration and what velocity are you trying to achieve? Or do you really mean "pushing forward a meter or two" instead?

 

[anorlunda]

It sounds like a baseball pitching machine scaled up to shoot mining rail cars.

 

[berkeman]

It sounds like a baseball pitching machine scaled up to shoot mining rail cars.

Reminds me of the Mentor party where you used your quad to launch us with the Human Slingshot. It was nice of @Evo to volunteer to go first!

 

[Lnewqban]

How are the wheels powered?
What are the required torque or pushing force, and angular speed of those wheels?
What is your idea about imposing enough friction or normal forces?

 

[DaveC426913]

4.After the object leaves, the powered wheels would tilt back to their “neutral” position.

Explain why this step is necessary (i.e. why you include it as a given).

Why not simply have the wheels under tension with a spring that defaults them to a minimum separation, rather than a maximum separation?

• The wheels are at minimum separation when there is no payload pushing through.
• As a payload gets pushed through, this forces the traction wheels out, while providing an optimal tension on the payload.
• Once the payload is shot out, of course the wheels snap back to closed position again.

Explain why this would not work.

 

[Quark62]

I'd like a little more detail on this before trying to give an intelligent response:

What are all these odd-shaped objects? How different are they?
Where are they being shot out to? Anywhere?
How much do they mass?Here is a suggestion for a solution:
What if the traction wheels were on the bottom? All your odd-shaped objects presumably have a bottom.

Hi @DaveC426913, thanks for your thoughts :)

Here are some clarifications:

- these odd-shaped objects are actually some stage props that we'd like to use for a performance. They're mostly of the same shape, but with slight differences in the slope angle

- to clarify, "pushed out to a certain distance" as @berkeman has mentioned would be a more accurate description. We haven't decided on how fast they should be moved, and we'd like to figure out how much traction we can give the objects first, and how to design that tilting mechanism to deliver that traction

 

[Quark62]

How are the wheels powered?
What are the required torque or pushing force, and angular speed of those wheels?
What is your idea about imposing enough friction or normal forces?

As of now, we're thinking the wheels could be powered by some large electric motors, in a similar fashion as those baseball pitching machines.

Hmm yeah eventually we'd need to get down to making calculations involving torque to size those motors

Friction would definitely be a concern. I think @Baluncore's suggestion on using low pressure is good

 

[DaveC426913]

- these odd-shaped objects are actually some stage props that we'd like to use for a performance. They're mostly of the same shape, but with slight differences in the slope angle

This sounds like a formula for disaster. Uncontrolled 50-100kg objects being fired out on stage like from a tennis ball gun. If you're lucky, you'll only injure performers, not audience members.

My advice - and my prediction - of the solution you will settle on: manual labour.

 

[Quark62]

This sounds like a formula for disaster. Uncontrolled 50-100kg objects being fired out on stage like from a tennis ball gun. If you're lucky, you'll only injure performers, not audience members.

My advice - and my prediction - of the solution you will settle on: manual labour.

Yep we'll make sure to control for a slow and safer speed.

Manual labour is definitely an option, but we'll like to see if we can automate it.

Hmm I'm thinking of a car suspension like system. The reason why we'd like for the wheels to return to a "neutral" position is so that they'd be ready to accept the next payload

 

[anorlunda]

I agree with @DaveC426913 . In fact, I'm reminded of the famous last words from WKRP

"As God is my witness, I thought turkeys could fly."

 

[jrmichler]

As of now, we're thinking the wheels could be powered by some large electric motors, in a similar fashion as those baseball pitching machines.

Hmm yeah eventually we'd need to get down to making calculations involving torque to size those motors

This is going at backwards. The right way:

1) Define what you are pushing out.
How large - smallest and largest.
How heavy - lightest and heaviest.
How strong - can they be gripped between wheels without getting squashed?
2) Define how hard they need to be pushed.
Are they sliding across the floor, or rolling on wheels?
How far?
Do they skid to a stop? Or getting stopped somehow?
3) What is the rate?
One object every few minutes?
Multiple objects per second?
Somewhere in between?
4) What are the timing requirements? Does each object have to be pushed out exactly at a certain time...
Plus or minus a millisecond?
Somebody saying "OK, go!"
Somewhere in between?
5) At least one more question that I did not think of.

THEN we can actually help you.

 

[anorlunda]

What @jrmichler said engineers call "requirements before design".

Requirements say what you need to accomplish.
Design says how you plan to do what's required.

You OP with the wheels, is saying how without first saying what.

 

[Stormer]

This is going at backwards. The right way:

1) Define what you are pushing out.
How large - smallest and largest.
How heavy - lightest and heaviest.
How strong - can they be gripped between wheels without getting squashed?
2) Define how hard they need to be pushed.
Are they sliding across the floor, or rolling on wheels?
How far?
Do they skid to a stop? Or getting stopped somehow?
3) What is the rate?
One object every few minutes?
Multiple objects per second?
Somewhere in between?
4) What are the timing requirements? Does each object have to be pushed out exactly at a certain time...
Plus or minus a millisecond?
Somebody saying "OK, go!"
Somewhere in between?
5) At least one more question that I did not think of.

THEN we can actually help you.

He is not asking for calculations, he is asking for a mechanical mechanism. So no those answers are not needed.

I am thinking that a solution is a second set of wheels that is freewheeling and on the same frame as the rotating wheels So the first set of wheels are used to align the second set of rotating "launching wheels" before the object reaches it. And then the joint can be spring loaded to get back to neutral position.

 

[Baluncore]

He is not asking for calculations, he is asking for a mechanical mechanism. So no those answers are not needed.

Why do you try to censor others suggestions?

What gives you such confidence that you have the only correct interpretation of the thread?

Do you really believe you can read the OPs mind?