Turn the press of a button or pulling into a rotation?

  • Thread starter xuzigemov
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  • #1
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Here's some basic mechanical engineering question for you guys.

How can one turn a press of a button (or pulling) into a rotation?

My goal is to be able to have the button in any orientation and position and still be able to rotate a dial 360 degrees when fully pressed/pulled by 5mm. I suspect this can be made with few springs and strings.

I think what happens inside mechanical dial indicators and hook weight scales is the clue, sadly any disassembly video or article I saw doesn't go into detail or talks about electric ones which lack the most important part I think.


I could go on to explain the actual device I'm trying to build but it involves computer vision and more components so would take a while to explain and complicate stuff.
 

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  • #3
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Thank you.

I was probably not clear in my OP.
When I said "My goal is to be able to have the button in any orientation and position and still be able to rotate a dial 360 degrees when fully pressed/pulled by 5mm.". What I meant to say I want to be able to rotate my button, attached to a ball socket joint. Only solution here to me seems one involving a string.
 
  • #4
berkeman
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When I said "My goal is to be able to have the button in any orientation and position and still be able to rotate a dial 360 degrees when fully pressed/pulled by 5mm.". What I meant to say I want to be able to rotate my button, attached to a ball socket joint. Only solution here to me seems one involving a string.
Hmm, could you Upload a sketch? That would probably help us in visualizing what you are wanting to do. You can use the Upload button in the lower right of the Edit window to Upload a PDF or JPEG copy of your sketch. Thanks.
 
  • #5
Averagesupernova
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So your dial is in a fixed orientation and whatever you push or pull can be in any orientation?
 
  • #7
berkeman
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Was the dial meant to move with each switch motion, or just the pressing motion?
 
  • #8
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Just the pressing
 
  • #9
berkeman
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Just the pressing
So in the animation, the dial should have rotated 360° when the button was pressed at the end? You might be able to accomplish that with pneumatics or hydraulics, or even still the rack and pinion mechanism. The lower end of the rack would be attached to the outside of the spherical bearing that encloses the ball at the top of the switch end.
 
  • #10
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The lower end of the rack would be attached to the outside of the spherical bearing that encloses the ball at the top of the switch end.
Sounds very interesting but not sure I follow. Can you rephrase this please?
 
  • #11
berkeman
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Sounds very interesting but not sure I follow. Can you rephrase this please?
Sure. In your animation, the rotation of the switch into different positions should not rotate the dial. Have the upper part of the switch be a spherical ball encased in a spherical shell that is the outer surface of the smooth bearing (ball in socket). The bottom end of the sphere is open enough to allow the switch to be tilted to each side as you show in the animation.

A vertical rack is attached to the top of the spherical surface, and engages a pinion gear near the center of the dial (maybe including an extra gear to step-up the linear motion to a full dial rotation). When the switch is pressed upward, that displaces the spherical shell and rack upward linearly, which rotates the pinion gear. The rack is spring loaded downward, so when the upward pressure on the switch is released, the switch and sphere+rack return to the full downward position.
 
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  • #12
Averagesupernova
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I'm confused. The video you linked to is an edge finder or something very similar which is used in machining. If you want it to move the dial only when pushed in, that would be a simple dial indicator. But you have a requirement that allows for moving the orientation of the button/plunger into any position and be able to accurately move the dial which is fixed? Is this correct?
 
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  • #13
berkeman
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But you have a requirement that allows for moving the orientation of the button/plunger into any position and be able to accurately move the dial which is fixed? Is this correct?
Oh, maybe I misunderstood then. @xuzigemov -- do you want the dial to move if the switch is pushed to the side, and then is pushed in somehow? That would require the hydraulic approach, I think.
 
  • #14
CWatters
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Perhaps you can use hydraulics?

Here in the UK you can buy remote pushbutton for operating the flush of a WC. They connect to the valve using a plastic tube that allows you to position the push button anywhere and in an orientation within say 2m of the flush valve.

Likewise you can get hydraulic brakes for bicycles.

Edit: I see Berkman best me to it.
 
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  • #15
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Never used hydraulics for my own projects. Only things worrying me is fear of leakage or contamination of liquid especially after prolonged use. I have a feeling some sort of spring setup with a rope/string could replace hydraulics tube if needed?

My actual device is not really a dial indicator but it works identically. It actually has a barcode marker instead of a dial that tells a computer vision camera how much the button was pressed based on the rotation of the marker relative to another fixed marker on the device.
 
  • #16
berkeman
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My actual device is not really a dial indicator but it works identically. It actually has a barcode marker instead of a dial that tells a computer vision camera how much the button was pressed based on the rotation of the marker relative to another fixed marker on the device.
Can you just use a linear potentiometer and read that with your computer directly? Seems a lot simpler.

Or is this for a schoolwork project where you are required to use that round-about way of getting the linear displacement information?
 
  • #17
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Yes, a sensor on the device itself requires external power or battery on the device. Like this it can provide info wirelessly without power.
 
  • #18
Averagesupernova
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My first question has still not been answered.
 
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  • #20
berkeman
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Thread is closed temporarily.

@xuzigemov -- check your Private Messages and please respond to the message I left you yesterday. Thank you.
 

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