GearHeads Forum

Hi:

  To place images, there is a "additional options " button below your message. Click it and a browse button will appear so
you can attach an image ( or 4)..

  I used a spring, because the ring of brass pins are always under tension from the CT spring, and the trigger can happen at any angle
so long as the two platforms are spinning in reverse direction with the bottom turning cw. Alway hard to explain these things ,,
which is why I hope to be able to allow simulations of mechanisms like this one. Kinetic triggering can be so nonintuitive that
Id like ot have a tool where I can play with shapes and how they interact as they spin .. might help creativity some.

Art

OK Art, gotcha. I get the jist of your engine. They are hard to describe, but here goes....

Here are pics of my unfinished project. The upper (inner) pawl is lifted by magnets glued to small dowels inserted in the outer wheel. They are adjustable, hence the extra holes. In the pic in the following post you can see the outer pawl catching the ratchet as the magnets lift the inner pawl. Gravity drops both pawls. The magnets are placed opposite the heavier end of the arm, to get the most from the back swing.

A couple more.....

Sorry for the huge pics, again, I don't know what I'm doing...... :-\

Huge pics are fine, I liek them that way, allows me to zoom in on detail.

You work as I do, experimentation, changes, more experimentation till it works. I
respect the process. I too tend to work that way, though the new bat was drawn and
conceived on paper, its the first one that was. Scimitar was seat of pants with many variations
whicgh is why the drawings and such are piced together. Im hoping the bat is better
able to be documented.

  Good work, keep it up..

Art

Art, I was thinking that David Roy's pawl is shaped to avoid slipping off it's pin. If you wanted to eliminate that spring you could sand the end of your pawl....

these pics show the wheel coming to rest, reversing position, and starting again.

Sorry posting when you replied....Thanks for your comments. Your seat of the pants design of scimitar is the reason I'm here!

Im not so sure that would work for this design..because of the way I designed the action of the trigger
it needs that spring to pull it back in just to eliminate the possability fo runaway ratchet.. but we'll see, that design
may see many changes as I piece things together..

Ill post videos as it starts to run.. if it starts to run..

Art

Ah, I see. I imagine the 4 lb. spring would make things get moving pretty quick. I accidentally bought a 4.5 lb. constant force (not torque) spring the other day. I have been wondering if it would work. I'm glad to hear yours does. I'll have to draw mine out it's 40" length to use it though. I've been trying to think of ways to incorporate it into a design. I imagine something like hiding the coiled end on a spool behind a faux flower pot (flat against the wall) and building a hollow flower stem to hide the rest of the spring,then a flower designed wheel like "Zinnia"on top. I'd wind a string on the Zinnia spool and attach it to the free end of the spring.

Or maybe the tail of some creature.

It's amazing once these machines get in your head, how much time you spend thinking about them !

The original bat used a constant force spring, I thought it was constant torque, so I
spooled it that way. Worked fine.. but the guys at Vulcan spring told me it was wrong and
may wear out prematurely

Art

That's interesting. The spring I bought is rated at 25,000 uses as compared to constant torque springs rated at 2500. I wonder how much it will be affected? Did you back wind your spring, or wind in the springs natural direction? Had you noticed a difference in lifespan on your creation?

I would love to be able to wind it, it being compact really leaves a lot of options.

I hope you don't mind the questions Art, I appreciate your time.

Eric

This spring is a bit of a monster