Help with a device like a salad spinner

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Discussion Overview

The discussion revolves around designing a simple mechanical device that spins in response to a downward force, akin to a salad spinner or plunger-style spinning top. Participants explore the requirements for the mechanism, including compactness and the need for all components to fit within a circular casing. The conversation includes technical challenges, design ideas, and clarifications regarding the project's constraints.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Homework-related

Main Points Raised

  • One participant describes the need for a mechanism that translates a downward force into rotational motion, emphasizing simplicity and compactness.
  • Several participants inquire about the specifics of the design, including whether all mechanisms must be contained within the circle and the nature of the downward force.
  • There are requests for diagrams, both 2-D and 3-D, to better understand the proposed mechanism and its components.
  • Participants suggest various analogies and examples, such as a plunger or a yoyo, to clarify the design concept.
  • One participant expresses confusion about how the proposed design differs from existing plunger-powered spinning tops.
  • Another participant questions how the action of pushing something towards the center would not interfere with the spinning edge of the disk.
  • There is a discussion about the necessity of a plunger in the design and whether it is a strict requirement.
  • One participant mentions the need for the creation to be novel, which adds to the complexity of the project.
  • Concerns are raised about the lack of specific constraints typically found in design projects, leading to skepticism about the project's requirements.

Areas of Agreement / Disagreement

Participants express various viewpoints regarding the design requirements and mechanisms, with no consensus reached on the specifics of the design or the necessity of certain components. The discussion remains unresolved with multiple competing ideas and clarifications ongoing.

Contextual Notes

Participants note the absence of a formal rule sheet for the project, which may contribute to the uncertainty in defining the design constraints. The discussion includes references to the need for a novel creation, which complicates the design process.

SaabGuy
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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
 
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Welcome to PF.

Is this project for schoolwork?

Can you show us your work so far on this project?
 
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.
 
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?
 
SaabGuy said:
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?
 
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?
 
bob012345 said:
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
 
SaabGuy said:
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.
 
berkeman said:
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
SaabGuy said:
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
bob012345 said:
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
SaabGuy said:
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
bob012345 said:
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
SaabGuy said:
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
berkeman said:
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!
 
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  • #18
SaabGuy said:
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?
 
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  • #19
bob012345 said:
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
SaabGuy said:
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
SaabGuy said:
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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