What mechanism should I use to convert sliding a motion to 45 degree rotation. 1

[MiniG1]

I am looking for mechanism ideas, examples or feedback on how I should convert the sliding motion of a part to the 45 degrees rotation of another one (see picture).

I have a "slider" of an undetermined shape that can move freely along the x+ axis. The slider is to be pushed by a human finger. I have another "pivot" part that can rotate around the z axis. A spring forces this part to go back to POSITION 1 at rest. I want to be able to force a rotation of this part by 45 degrees (POSITION 2) when a x+ motion is applied on the slider. When the slider is released, I want to the pivot part and the slider to go back to POSITION 1.

I am open to change the shape and/or mechanism for both parts, as long as what is described above is respected. The slider would be stuck in a rail / cannot move along the y nor the z axis. The diameter of the pivot part is ~6mm and the sliding motion would only be of a few mms (~2mm). The parts would be made of zinc alloy.

Thanks

 

[GregLocock]

what you have drawn will work in the absence of friction and wear but you are obviously unhappy with it probably for good reason. I'd expect the slider to jam in the guides, it needs to be longer. I'd expect the bottom left corner of the slider to dig into the cam, it needs to be radiused .

Cheers

Greg Locock


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[IRstuff]

What stops it from over rotating?

Why not something like below? The movement is self-stopping as the other side bottom out on the moving block to limit the motion to 45 degrees.

TTFN (ta ta for now)
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[MacGyverS2000]

Big problem with that cam, IR... you'll constantly hear "wocka wocka wocka" all day long

Dan - Owner

http://www.Hi-TecDesigns.com

 

[robyengIT]

Google : "ingenious mechanisms for designers and inventors - Jones" Vol 1 - Vol 2 - Vol 3 - Vol 4 (free download)

 

[IRstuff]

"you'll constantly hear "wocka wocka wocka" all day long"

Then, you'll know it's working ;-) ; my current dishwasher is too quiet, requiring me to go the washer to hear if it's still washing.

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

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[hydtools]

I would add a pinned link between the two and eliminate the slidy contact between the pusher and cam.

Ted

 

[GregLocock]

Then you get to design a pinned joint as well, but I must admit a conrod was my first thought. Of course, since we don't know what the environment is, or what the volumes are, or if this is for a toy or a medical device, it's all a bit airy-fairy.

Cheers

Greg Locock


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[hydtools]

Integral rack and gear features could work, too. Could all be cast. We don't know what other function, if any, the cam piece has.

Ted

 

[hendersdc]

Another option would be to reverse the spring, wrap a cable or belt around the cam, and attach the end to the slider.

 

[MiniG1]

Thanks for all the responses. The overall mechanism is about ~20mm length x 8mm height and should be as simple as possible, to reduce the number of parts and weight. It is to be used as part of a larger ratchet mechanism. The cam piece is actually part to a ~30 mm tube, positioned along the z axis on my drawings. The pawl of the ratchet mechanism would be positioned at the center of the tube. My goal is to prevent the pawl from touching the ratchet wheel when a x+ slide motion is applied (wheel can move freely). When released, the pawl goes back on the wheel and is "locked" in place.

Cheers!

 

[chicopee]

Put a wheel at the end of the slider.