[TheForge] Treadle Hammer Springs

[Bruce Freeman]

I suppose you could.  It would have to be heavy enough not to stretch too much when you first step on it, yet light enough that it will stretch a bit to absorb the shock.

But if the treadle stops at the floor level, I don't think it's all that much shock on the leg.  If it stops significantly above the floor, maybe that's the problem.

Another issue is the linkage ratio.  The Grasshopper uses a 2:1 ratio - 1" of treadle motion gives 2" of hammer motion - a mechanical DISadvantage.  That may mitigate the shock somewhat.  It may not be possible to use such a ratio on other hammers due to the fact that it would increase the force against the leg.

Bruce
NJ

>>> wmullett at bright.net 3/21/2007 12:20 PM >>>
Bruce,

Your the wiz-bang at the mechanics of these.  Since most of the real force of hammering comes from the inertia of the hammer, why couldn't you use a heavy spring on the treadle connection to the head that will reduce the impact to your leg.

The Chinese use split bamboo sledge hammers for that reason.  They kind of act like a wet noodle when they swing them.
---------------
From: Bruce Freeman <freemab222 at yahoo.com>
Date: Tue Mar 20, 8:58 PM
To: Sponsored by ABANA <theforge at mailman.qth.net>
Subject: Re: [TheForge] Treadle Hammer Springs

Do you have any way of adjusting WHERE this stop
occurs?  It would probably be less jarring if it
stopped at the floor - where the leg is fully
extended.  (Another feature of the Grasshopper.)
<Grins and polishes nails on lapel.>

Bruce

--- Marc <marc at ironringforge.com> wrote:

> Actually, Bruce, the part of the treadle hammer that
> bothers my knees
> the most is the sudden stop when the blow hits the
> work. My leaf spring
> cushions that blow very nicely.
> 
> The spring tension affects my own energy level much
> more than my knees.
> I find I can draw out some good size stock pretty
> quickly, but I'm
> pretty winded after a while. I think using your
> half-spring idea would
> help quite a bit there, and I;m anxious to try it
> out.
> 
> --Marc
> 
> 
> On Sun, 2007-03-18 at 19:12 -0700, Bruce Freeman
> wrote:
> > Middle aged knees... I know about those.  I
> sometimes
> > wonder whether it's worse to exercise or not to
> > exercise!
> > 
> > Build a Grasshopper and you'll have NO spring
> tension
> > working against your leg!
> > 
> > Bruce
> > NJ
> 
> 
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