turn a press of a button or pulling into a rotation? 2

[xuzigemov]

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.

 

[SwinnyGG]

Dial indicators work using a (very small, very precise) rack and pinion. The arrangement is simple- rack teeth are cut on the spindle and the pointer is connected to the pinion either directly or through a reduction.

To turn a shaft 360 degrees from a button press is certainly physically possible. The short stroke of a button press, along with the low force you'd have available due to ergonomic concerns, means the force available as a torque output from your pinion will be small.

If that meets your needs, then your design can be very simple.

 

[rb1957]

yes, it's easy to convert translation motion into rotational ... consider a spiral groove on the shaft of the pin ... the pin is pushed and the body rotates.
google "rotational push pins". another solution is having the pin drive the tangent of the rotation.

Magnitudes and constraints could make this difficult.

another day in paradise, or is paradise one day closer ?

 

[xuzigemov]

Thanks guys.


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.

 

[rb1957]

you want to convert rotational to translational movement. ok, I think the same spiral idea works ... rotate it and it should drive a translation.

another day in paradise, or is paradise one day closer ?

 

[IRstuff]

Perhaps a drawing is in order. It sounds to me like you want a button that's in "any orientation" relative to a dial, and you want a 5-mm depression of the button to result in a 360° rotation of said dial.

Seems to me, if that's the case, that bicycle controls that use steel cables to actuate gear shifts and brakes could be worth studying.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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[Compositepro]

Throttle or choke cables used in old cars and lawn mowers will do what you want. A wire is pushed or pulled though a sleave, which then moves a crank lever on a shaft, so the shaft turns.

https://www.google.com/search?q=cho...HSZWBz0QsAR6BAgGEAE&biw=1426&bih=768&dpr=1.25

I was pretty surprised when I first open the hood on a Honda fit that I bought for my daughter and there was no throttle cable.

 

[MintJulep]

I was probably not clear in my OP.

No, you weren't.

And your follow-up didn't improve things.

 

[rb1957]

guys, his 2nd post revises the problem to converting rotational movement into translational (the opposite of his original post, as I and others read it).

he also seems to have the dial mounted on a uni-ball (for whatever reason). I still think a spiral groove in the dial will work for him ... with a flex cable (to account for the uni-ball).

another day in paradise, or is paradise one day closer ?

 

[BUGGAR]

"...........so would take a while to explain."

Please feel free to take the time.

 

[xuzigemov]

Okay:

https://www.youtube.com/watch?v=mpk4KtWQqOc

 

[btrueblood]

So, according to your video, you want a dial to remain motionless regardless of how an appended knobby thing is twiddled?

 

[MintJulep]

So you are designing a device to introduce errors into measurements?

 

[SnTMan]

So, according to your video, you want a dial to remain motionless regardless of how an appended knobby thing is twiddled?

Easily done, eh

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[rb1957]

maybe he'll record the indication before moving the "knobby thing" and maybe he'll calibrate with the "knobby thing" in different positions (if only to know that it does translate the same in different orientations).

another day in paradise, or is paradise one day closer ?

 

[drawoh]

xuzigemov,

Is this to be a mechanical device
If I push a button 5mm and a dial rotates 360[°], that dial had better be small, light and low friction. Otherwise, the button forces will be very high. Usually, mechanical actuators activate mechanisms that multiply the force, and reduce the actuated distance. I pull a lever one foot (300mm), and some clamp moves a quarter inch (6mm).

Maybe this is a good application for an electric actuator.

--
JHG

 

[MacGyverS2000]

Are you looking to place a mechanical pushbutton at the end of a ball/socket joint, where the socket portion attached to the dial indicator can rotate around the ball joint 260 degrees?

If so, WTH for? If not, my guess is as good as everyone else's...

Dan - Owner

http://www.Hi-TecDesigns.com

 

[3DDave]

For what it's worth:

https://www.youtube.com/watch?v=Rp6D3YTx7iU

"WHAT MAKES IT WORK? #18 "How a Dial indicator Works" tubalcain"

Any tubalcain video is an interesting one.

 

[IRstuff]

I think the bicycle or choke cable concept is the only go-path available. However, if you are actually trying to measure a change in position, the accuracy will suck, compared to what the dial indicator can actually do under normal conditions.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

https://www.youtube.com/watch?v=BKorP55Aqvg

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