[TheForge] Krause/Nazel type air hammer

[Jerry Frost]

Well, I've spent half a dozen hours surfing the patent servers, scratching
my head over the drawings and coming to some "early" opinions.

My first opinion is: The US Patent and Trademark web site is a pain to try
searching, you have to know the exact name and or patent #. If I knew that
much I wouldn't be searching their site. Of course I may just not know how
to search the site but followed the directions as well as I could. <sigh> On
the up side they offer pretty complete drawings and text.

My second opinion is: http://ep.espacenet.com/ is an easy server to search
but you have to order the text. Another limitation is how far back it'll
retrieve info, 1926 was as early as I got results for but it was a first
try. <grin>

Anyway, I used "espacenet" to locate the patent # then the US patent server
to retrieve reasonably complete drawings and text. I'm not looking for
dimensioned drawings and specs as I'm trying to grasp the concepts being
used.

Now for opinions about self contained power hammers, the valving and some
hypotheticals on what and how I'd do it. All opinions gladly open for
dispute. <grin>

Many of the control valving schemes are very similar to the drawings Steve
sent. They're needlessly complicated in my opinion and most would require a
mill in addition to a lathe unless you REALLY like hand work.

The Massey Hammer Patent # 707246  Aug.19/1902 has a much simpler valving
scheme and looks quite a bit like Mike's Alldays and Onions valve. There are
some differences in the shape and type of relief springs but essentially I
"think" they work the same way.

Mike, the next time you have the Alldays and Onions untarped would you mind
looking up it's patent number? The US patent server goes back to 1795 so
should have some drawings.

The Beche Hammer Patent # 788876 May 02/1905 has the simplest valving scheme
I've seen so far. However it has about the most complex ram shapes I ran
into too. A lot of it's valving is piston port rather than the spring relief
the other hammers use.

All of them use the same funky rotary valves though and I can certainly see
why folks are adapting to spool valves. It's NOT because they WANT to make
them on a lathe, it's because you CAN make them with a lathe. The rotary
valves would require a mill or much file work.

Okay, so far my opinion is defined by my experience. (what else? <grin>) Use
the SIMPLEST system that will do the job. KISS. The Beche has the simplest
looking valving but the Massey's is only just a bit more complicated and it
has much simpler porting and pistons.

I think I came up with an even simpler valve scheme with only three
positions to: retract, run and clamp. Strength/speed would depend on treadle
position. A single blow would be a matter of foot speed. Okay, so it's not
perfect. However, the valves are really simple sliders. Basically they're a
round bar with areas ground away. They slide in a vlave body with only two
ports per slider. I'll try making some clean sketches and see if I can talk
the wife into letting me use her scanner.

Regardless, I can certainly see why almost anything but the rotating valves
is preferable to folk without a real machine shop.

One last idea to toss out here. We all know the Kinyon style hammer's work
well, the only real downside is having to have enough compressor to make it
go, especially for larger weight hammers. The self contained hammers solve
the forehead wrinkling (for me) problem of a recipricating ram by simply
using compressed air as a "drive" train to convert a crank shaft's motion
into the piston's motion. Big gain is cushion and controllability not
available in a mechanical.

How about we combine the two? Instead of trying to figure out a reasonable
way to make these valves at home we simply make the master cylinder into a
compressor with a couple flap valves, feed it to a small reservoir and use
it to power a Kinyon controlled ram? One of the real beauties of the Nazel
et,al. hammers is low pressure air. High volume low pressure air is much
easier to come up with than high pressure low volume air. The only mods to
the Kinyon valving necessary is enlarging them to carry the volume.

Using my calculator watch I found: 8.49" dia. master cylinder feeding a 6"
dia. ram cylinder with 15 psig air develops 424 lbs of force. This should
drive 100-200 lbs of ram pretty well, regardless of the vlaving scheme. This
sounds pretty darned attractive to me so I started thinking "how to"
thoughts.

First I think I'd use aluminum for the master cylinder, piston and as many
of the valve bodies as possible to shed excess heat. don't know if it'd be a
good idea for the ram cylinder and certainly not the hammer ram itself.
There are a number of reasons to make the master cylinder from aluminum:
It's easy to machine. It's light so there'll be less stress on the cranking
mechanism. It'll shed the heat of compressing air well. I'm sure there are
more pros I haven't thought of and I can't think of many cons.

Seeing as we're working with low pressure high volume air we have a lot of
leeway designing the master cylinder, the larger it's diameter the shorter
we can make it's stroke and make enough air. The shorter the stroke, the
faster the cycle rate. Fast is good. Right? We can make it go slower with
treadle control. A shorter stroke also means we can gear the motor down and
perhaps get away with a smaller motor. Not having 3 phase power within a
quarter million dollars of my place I'll be using a gas or diesel engine
driven hydraulic motor to run the thing. (if I ever find time to build one.
<sigh>)

Well, it's bed time and I think I've tossed enough stuff out for one night.

Frosty
------------------------
If it ain't forged
it ain't real.
Wrought iron is.
The FrostWorks

Meadow Lakes, AK.