[TheForge] ALT Treadle Hammer Springs

[Richard Maynard]

I'm intrigued by this. Impressed as I am by the Grasshopper I am drawn to 
something cheaper, simpler and easier - I'd rather spend time forging than 
making tools! I think for me a treadle hammer's main use is to replace a 
striker so I can use fullers etc. single handed.

 Is it possible that a largish air cylinder could provide 'guides' for the 
hammer? In which case maybe something like the renderings I've uploaded to 
the Photoaccess site could work. Look in the 'air spring hammer concept' 
album. Probably needs some tweaking to the linkage lengths etc. - but what 
do people think?

Cheers,

 Rich M.
----- Original Message ----- 
From: "Jerry Frost" <frosty at customcpu.com>
To: <artgawk at thegrid.net>; "Sponsored by ABANA" <theforge at mailman.qth.net>
Sent: Wednesday, March 21, 2007 5:59 PM
Subject: Re: [TheForge] ALT Treadle Hammer Springs


>I have a little experience with pneumatic accumulators (spring analogs) and 
>don't have an idea how well they'd work on a TH.
>
> A shock absorber defeats the purpose, they're intended to damp rebound and 
> you want your hammer head to rebound.
>
> A pneumatic accumulator doesn't need to be heavy at all, there is a local 
> car wash that uses them instead of garage door springs and they're 3" PVC. 
> The garage doors feel a little odd but lift easily enough.
>
> In theory pneumatic accumulators will replace mechanical springs in any 
> linear application. In practice they don't do so well where they see a lot 
> of movement as developed heat alters their action. A few years ago the 
> head guy at Heavy Duty decided to replace the relief springs on the belly 
> blades with a gas over hydraulic accumulator system. A belly blade used in 
> a city needs to be able to give when you catch an obstacle like a high 
> manhole, drop drain, etc. If there's no give in the blade they tend to get 
> torn off doing considerable damage to all involved. Anyway, the gas over 
> hyd accumulators worked okay for a while but after they got hot you 
> couldn't lift them fast enough to avoid problems. They'd SHOOT down but 
> creap up.
>
> A little experimentation would answer the question regarding TH 
> applications.
>
> Frosty
> -------------------------------
> If it ain't forged
> it ain't real.
> Wrought iron is.
> The FrostWorks
>
> Meadow Lakes, AK.
>
> http://www.artmetalradio.com/
>
> From: "Peter Fels And Phoebe Palmer" <artgawk at thegrid.net>
>
>
>>
>>
>> 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
>>>
>
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