[TheForge] ALT Treadle Hammer Springs

[Peter Fels And Phoebe Palmer]

Jeffrey Polaski wrote:
> Now that I read the message, I see I wasn't clear. I'm not sure what
> they are called, but I was thinking of the big bag-type shocks, not the
> regular car air-shocks.

Shocks per-se sort of defeat the intended use. The bladders are, 
in effect, compression springs but the object here is to have a 
smooth, efficient, frictionless way to make the hammer tup 
gravity neutral...and the truck bladder doesn't sound all that good.
But a tightly inflated rubber ball in place of a compression 
spring might work. There's more than one way to use air for a 
spring and it'd be valuably valveable.
Looking at some independent front suspensions with their double A 
arms moving in parallel and their supplied spring and mounts ,has 
me wondering if we aren't neglecting a ready-made treadle hammer 
mechanism?
Yeah, you'd wanna take off the shock absorber....pf
  Those might work, too, but I'd think they would
> wear out fairly fast. 
If you consider that 1/4 of the vehicle is riding on that shock, 
and how many times a second it goes up and down at freeway 
speeds, You'll see that wear isn't going to be a big factor in a 
TH application...pf
> 
> Jeff Polaski
> 
> 
> 
> -----Original Message-----
> From: theforge-bounces at mailman.qth.net
> [mailto:theforge-bounces at mailman.qth.net] On Behalf Of Jeffrey Polaski
> Sent: Tuesday, March 20, 2007 1:02 PM
> To: artgawk at thegrid.net; Sponsored by ABANA
> Subject: RE: [TheForge] ALT Treadle Hammer Springs
> 
> Just thinking out loud... does anyone know if anyone has used air shocks
> off a semi truck/trailer? I bet those things would make great springs.
> They'd certainly be easy to adjust.  I'd hate to pop one, though --
> you'd have to make some sort of cover to keep hot metal away from it. 
> 
> Jeff Polaski
> 
> -----Original Message-----
> From: theforge-bounces at mailman.qth.net
> [mailto:theforge-bounces at mailman.qth.net] On Behalf Of Peter Fels And
> Phoebe Palmer
> Sent: Tuesday, March 20, 2007 12:52 AM
> To: Sponsored by ABANA
> Subject: Re: [TheForge] ALT Treadle Hammer Springs
> 
> Neat idea Paul!
> One could use a big hairy old cylinder for the guides and it's 
> piston for the tup.
> The only problem i can see would be overcoming piston ring friction.
> Having gone that far, might as well add a pressure release valve 
> to the treadle...grin...pf
> 
> paul wrote:
>> Some years ago while bench forging, the blacksmith equivalent of bench
> 
>> racing in gearhead circles, I suggested that an air spring might be a 
>> good way to replace the springs in a treadle hammer. Steve White of
> UMBA 
>> had a treadle hammer that used a 6" or 8" steel pipe for the backbone
> of 
>> the hammer. Since the pipe was sealed at both ends it made a perfect
> air 
>> reservoir. The idea was to use an air cylinder in place of the spring,
> 
>> and connect that to reservoir with a volume about 100 times as large
> as 
>> the displacement of the air cylinder. When the system is inflated to a
> 
>> sufficient pressure to raise the hammer, the force to move the hammer 
>> would not change much on the down stroke, as the volume of the air 
>> reservoir is many times that of the cylinder. Steve reported that it 
>> worked. I don't know if he is still using this system, but it might be
> 
>> worth considering. By supplying the reservoir with a small air
> regulator 
>> you can adjust the force required to move the hammer head, and by 
>> diddling the ratio of the two, cylinder to reservoir, you can alter
> the 
>> increase of force that is required to move the hammer throughout its 
>> range to suit.
>>
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