Help with a device like a salad spinner

  • Thread starter SaabGuy
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  • #1
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I would like to discuss a simple mechanical system for a project of mine. Here it is if anyone can solve it:
Allow me to explain what is required. The circle needs to spin via a downward force represented by the black arrow. The red arrow is the direction the downward force needs to be translated to. Think of it as a push salad spinner or a plunger spinning top. And just like those two objects, once the downward force is released, the circle keeps spinning, and continued application of downward force increases the speed of the circle (just like a salad spinner or plunger style spinning top). The rules are:
- The mechanism has to be extremely simple and compact
- Be able to fit in your pocket
- The parts all have to be inside the circle


Screen Shot 2021-09-03 at 10.31.39 AM.png
 

Answers and Replies

  • #2
berkeman
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Welcome to PF.

Is this project for schoolwork?

Can you show us your work so far on this project?
 
  • #3
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It is for a school related project, it's a very open project. I have been trying to think of the mechanism that would allow the desired movements. I'm posting on here to see if there is anyone who has experience and would know off the top of their head how to do it.

Thanks.
 
  • #4
berkeman
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I'll move your thread to our schoolwork forums then. And for schoolwork projects especially, you are expected to show lots of work before we can offer tutorial help. Can you say how each of the example mechanisms that you mentioned would need to be modified to work in this project?
 
  • #5
bob012345
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It is for a school related project, it's a very open project. I have been trying to think of the mechanism that would allow the desired movements. I'm posting on here to see if there is anyone who has experience and would know off the top of their head how to do it.

Thanks.
Do you mean literally that everything must be inside the circle, there is no mechanism outside and the force must be downward? What kind of size is this to be? Do you have a first attempt at a solution or at least an idea?
 
  • #6
berkeman
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Also, so far your simple diagram is 2-D. Can you post a 3-D sketch of how the plunger relates to the spinning thing? What resists the downward force on the plunger?
 
  • #7
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Do you mean literally that everything must be inside the circle, there is no mechanism outside and the force must be downward? Do you have a first attempt at a solution or at least an idea?
Correct, everything is to be inside of the circle, no mechanisms outside of the circle. The force must be downwards, or to be more specific, towards the centre of the circle.
Here is a crude diagram of something that may work.
1630683952733.png
 
  • #8
bob012345
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Correct, everything is to be inside of the circle, no mechanisms outside of the circle. The force must be downwards, or to be more specific, towards the centre of the circle.
Here is a crude diagram of something that may work.
View attachment 288533
But then wouldn't the plunger, if that's what you use, be at least partly outside? Please draw the circle in relation to the mechanisms? Is it more like a circular case with a certain thickness? Is it flexible or deformable? Thanks.
 
  • #9
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Also, so far your simple diagram is 2-D. Can you post a 3-D sketch of how the plunger relates to the spinning thing? What resists the downward force on the plunger?
I have been trying to learn Fusion360, I will try my best to provide a 3D sketch. But for the time being, I am thinking of a simple gear system that will spin the outer circle. I just can't piece it fully together in my head.
 
  • #10
bob012345
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I have been trying to learn Fusion360, I will try my best to provide a 3D sketch. But for the time being, I am thinking of a simple gear system that will spin the outer circle. I just can't piece it fully together in my head.
A simple paper sketch would be fine for now.
 
  • #13
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But then wouldn't the plunger, if that's what you use, be at least partly outside? Please draw the circle in relation to the mechanisms? Is it more like a circular case with a certain thickness? Is it flexible or deformable? Thanks.
To reword the question: Take a plunger style spinning top, rotate the plunger 90 degrees and place it inside the spinning top. Now what mechanism will translate the force of pressing down on the plunger to spinning the spinning top. Difficult question I know! lol. Need to think outside the box on this one.
 
  • #14
bob012345
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To reword the question: Take a plunger style spinning top, rotate the plunger 90 degrees and place it inside the spinning top. Now what mechanism will translate the force of pressing down on the plunger to spinning the spinning top. Difficult question I know! lol. Need to think outside the box on this one.
I'm sure we have ideas but what can you think of? Also, how big is the device and must there be a plunger? Is that part of the rules?
 
  • #15
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I'm sure we have ideas but what can you think of? How big is the device? Also, must there be a plunger? Is that part of the rules?
Pocket size, no plunger, that was simply an example. The core of the idea here is to just get a circle spinning from pushing something towards the center of the circle, all on one axis.
 
  • #16
berkeman
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Pocket size, no plunger, that was simply an example. The core of the idea here is to just get a circle spinning from pushing something towards the center of the circle, all on one axis.
How does the action of pushing something not interfere with the spinning circumference/edge of the disk?
 
  • #17
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How does the action of pushing something not interfere with the spinning circumference/edge of the disk?
I'm still trying to figure that out. But I do enjoy talking about it and thinking it through!
 
  • #18
bob012345
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I'm still trying to figure that out. But I do enjoy talking about it and thinking it through!
Do you have an official rule sheet from this project you can share with us?
 
  • #19
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Do you have an official rule sheet from this project you can share with us?
No I do not, just that it has to be a novel creation... Hence the difficulty. But I feel like such a device does exist, it does not seem enormously complex..
 
  • #20
bob012345
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No I do not, just that it has to be a novel creation... Hence the difficulty. But I feel like such a device does exist, it does not seem enormously complex..
I think you will come up with something but it really has to be your idea. If we just tell you what to do it won't help your education.
 
  • #21
berkeman
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No I do not, just that it has to be a novel creation...
That's a little hard to believe for me. In my design classes in University, the project definitions (even for very creative projects) did have several constraints to them. What class is this for?
 

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