Most people are probably familiar with Leonardo hammer cams. But I'd like to make a motor-powered hammer that swings more like this (apologies for the crude diagram): enter image description here

The hammer would fall due to gravity, then get dragged along the ground on its way back up.

Of course, this diagram does not work, because the hammer on the way up needs to make a >= 90 degree angle with the wheel radius in order to fall (step 2), but needs to collapse to < 90 degrees in step 4 in order to drag along the ground.

Is this doable with simple, hardware store components?

  • $\begingroup$ Why do this - the link shows a system that uses much less energy ie the distance the hammer has to be moved. $\endgroup$ – Solar Mike Apr 27 at 6:40
  • $\begingroup$ it’s for an art project $\endgroup$ – neptune Apr 27 at 16:29
  • $\begingroup$ Have look at the motion here : youtu.be/n-2YN_Ak9eE $\endgroup$ – Solar Mike Apr 27 at 17:58
  • $\begingroup$ This is called a flail. It is often just a head on a length of chain fixed to a wheel.flail mower, excavator flail, tank flail $\endgroup$ – Phil Sweet Apr 27 at 18:00
  • $\begingroup$ @Solar Mike yes that's exactly the motion I would love to recreate $\endgroup$ – neptune Apr 27 at 18:30

It may work if you modify the legs of the handles properly and possibly allow a bit of vertical play in the axis of the wheel.

Just as an alternative you can put the hammer passing straight through a spring loaded sleeved hole in the disk. here is a sketch.


enter image description here

  • $\begingroup$ Ah ok, just to clarify by "ally vertical play" -- you mean when the hammer is dragged on the ground, another motor raises the wheel? If so that makes sense. Can you explain a bit more what you mean by having a spring loaded sleved hole in the disk? $\endgroup$ – neptune Apr 27 at 6:25
  • $\begingroup$ I draw a sketch later. But if you could imagine just a straight long handle passing through a drilled bushing with pre loaded spring to give it a jerk at the right moment. I will modify my answer. I meant allow not Ally. Sorry. $\endgroup$ – kamran Apr 27 at 6:45
  • $\begingroup$ Would love to see a sketch, thank you $\endgroup$ – neptune Apr 27 at 16:37
  • $\begingroup$ @neptune, I added my sketch. hope it clarifies my point. $\endgroup$ – kamran Apr 27 at 18:36

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