2
$\begingroup$

I have a basic design of two arms which need to be brought together. But I tried the design using a test setup and it did not work successfully. Here is a diagram of my design - enter image description here

What I observed is that arm 2 moves up before arm 1. I want both of them to move towards each other to cause a compression, and away from each other to cause expansion. Is there any way in which that could be achieved using minimal design requirements?

$\endgroup$
2
  • $\begingroup$ Have the arms connected with gears at their pivot. $\endgroup$ – Solar Mike Apr 3 '20 at 12:28
  • $\begingroup$ @SolarMike: That's the same solution I was thinking of. Even if short and sweet it belongs in an answer, not a comment. $\endgroup$ – feetwet Apr 3 '20 at 13:26
2
$\begingroup$

I can think of two options:

1) have the arms connected by gears at the pivot point - when one is moved so will the other, in fact one could be fixed...

2) connect the arms with a threaded rod (needs left & right hand threads) and use a pulley to rotate the rod - then the arms will move according to the pitch of the thread - actually 1 turn will move twice the pitch.

$\endgroup$
3
  • $\begingroup$ in both these cases, how will the rotation in any one direction, cause the arms to move in opposite directions? Could you explain that? Thanks $\endgroup$ – blazingcannon Apr 3 '20 at 13:48
  • $\begingroup$ Think of a pair of calipers, some have a threaded rod (with left & right hand threads) which means they open and close with rotation of the rod. With gears if one move then the other moves... $\endgroup$ – Solar Mike Apr 3 '20 at 13:52
  • $\begingroup$ Thanks a lot! Makes sense, but just be sure, it will cause both the arms to move right? I.e none of the arms are stationary, because I want it to compress a material kept in the middle equally on both the opposite faces. $\endgroup$ – blazingcannon Apr 3 '20 at 14:03
2
$\begingroup$

There are many ideas which have worked for different gears

like this drafting compass with a threaded shaft and a roller:

drafting compas

And this pantograph.

.

pantograph

-

$\endgroup$
0
$\begingroup$

You could try 2 bar linkages, it's basically what you're already trying but without a pulley and unequal displacement.

$\endgroup$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.