[TheForge] treadle hammer design (was: treadlehammeranvils)

[Mike Linn]

In general terms balance =3D control, imbalance =3D force.

mike


At 04:20 PM 1/24/03 -0500, you wrote:
>Marc,
>
>First, without regard to the "why" question, it is my observation based=20
>upon real tests that a see-saw hammer is slow.  "Experimental observation."
>
>Now, let's see what we're comparing.  No question that putting one 25-lb=20
>child on each end of a see-saw will result in a balance, or weightless,=20
>condition.  But how fast does a see-saw move?  Ever see one move real fast?
>
>To get motion out of it at all, there would have to be some degree of=20
>IMbalance when the hammer was at the anvil.  The opposite weight would=20
>have to provide a return force.
>
>(As I mentioned earlier, this can be done by using a see-saw bent downward=
=20
>at the pivot point.  Hence lowering the hammer is lifting the weight, and=
=20
>they are out of sync. so there WILL be a return force by the time the=20
>hammer hits the anvil.)
>
>The problem is that if that is a SMALL force (because most of the=20
>counterweight is still balancing the hammer) the acceleration will be low,=
=20
>and the hammer will not move fast.  It's not that it couldn't be MOVED=20
>fast, it's that there isn't the force to do it.
>
>Remeber that we're comparing this to a spring.  By the time we strike the=
=20
>anvil with the ram of a treadle hammer, the spring is stretched a good=20
>deal and provides a snappy return force.  Unfortunately WE really provide=
=20
>that force in stretching the spring in the first place =AF that's the=20
>problem we're trying to fix here.  The ram is NOT at "near-zero" gravity=20
>when it hits the ram.  It's at a substantial NEGATIVE "gravity" (=3D spring=
=20
>force).
>
>Did I make that clear?
>
>BTW, for the two 25-lb weights to add to 50 in effect, it would be=20
>essential to have zero slop in your pivot bearings and all other=20
>links.  Otherwise at best you'd get a dead-blow hammer of 50 lb total.
>
>Bruce
>NJ

         Michael Linn
       Artist Blacksmith
      McCalla, Alabama
       AFC Webmaster
http://afc.abana-chapter.com=20