[AT] Clark Airborne Dozer(now grounds) (Long)

[Francis Robinson]

--On Friday, January 04, 2008 12:44 AM -0600 Ralph Goff <alfg at sasktel.net> 
wrote:

> I've heard a similar theory in which a chain is dragged from the axle of
> a  combine to eliminate the build up of static electricity. This was
> supposed  to keep dust from sticking to the cab windows. Its an
> interesting idea but I  have never gotten around to actually trying it
> out.
> I"ve also never used a ground chain for any of the tractor belt work done
> on  this farm and I don't recall my Dad ever trying it either. I have
> never seen  any indication of static electricity build up and I am about
> as susceptible  to electric shocks as anyone can be. The worst is in our
> dry winter weather  when every time I get out of a vehicle I get a real
> jolt of static when I  touch the metal door frame.
>
> Ralph in Sask.


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


	Hi Ralph:

	Its finally warming up here a little. Maybe 40 today and 60 by early next 
week with a low of 50.   :-)   We are often well below zero during this 
time period.
	I dragged a short piece of chain from the steering axle of my old Gleaner 
all of the time I had it and from my old Deere 45 before that. I can't 
really say if it helped or not. The concept was supposedly started by guys 
that attached a short chain so it was easy to hook up if they got stuck 
without crawling underneath in the mud. They then claimed that it helped 
keep the glass a lot cleaner. Also a few guys reported getting zapped when 
touching the combine when they were standing on the ground and the 
separator was running. I don't believe I ever got zapped by a combine.
	I also don't recall ever getting zapped by a tractor running a belt driven 
machine. I was about 12 when I read about using a ground for belt work and 
just started doing it. One place it was discussed was in the old 4-H 
tractor maintenance project. I would think that as long as the machine 
being driven was making metallic contact with the ground that any charge 
would be discharged there. Our hay blower was in ground contact and also 
staked down with steel stakes. I would suspect that stuff like the dry hay 
moving through the metal pipes would be as likely as anything to build a 
static charge. Not only could that "maybe" feed back to the rubber tired 
tractor but I suppose it could also generate an ignition spark in a dust 
filled environment. My buzz saw is also in metallic contact with the ground 
and is also staked down with steel stakes. About the only thing I can think 
of off of the top of my head that might be not grounded in use would be a 
threshing machine on rubber tires and just chocked in place. Again the 
larger chance of generating a static charge might be from the material 
moving through the machine especially through the straw blower pipe. That 
also could be a bad place for a spark but I don't remember ever hearing of 
a straw pile burning unless it was from the sparks from a steam engine.
	Static is a funny thing. I have a primary filter in my furnace that is a 
plastic foam material that builds a static charge from the air passing 
through it and that charge is what causes it to catch the dust in the air. 
The attraction is quite strong and even though the foam is rather open 
celled it fills up with dust pretty quickly.
	Anyone that is into woodworking to the point of having dust collection 
systems probably knows about static build-up in plastic dust collector 
piping. In most shops a ground wire is ran either inside or outside of the 
pipe (it doesn't seem to matter which) to drain off the static charge 
caused by the air moving through the plastic piping. Metal piping systems 
are usually self grounding and not as prone to build a charge as plastic. 
There supposedly has never been a reported case of a fire or explosion in a 
home shop setting from the static but a number of guys have been zapped 
silly...   :-)   In industrial settings I understand that there have been 
fires and explosions and that most insurance companies require grounding of 
such systems.
	When I got married about 45 years ago I was working in a plastics factory 
working with rolls of plastic film and we were zapped constantly, sometimes 
hundreds of times a day. While most people worked in the same department 
and often at the same machine for their entire term of employment with the 
company they had decided to try something different with me. Since I had 
good mechanical skills and could learn about any job quickly I was declared 
a "Utility man" (actually some days I was declared a lot more than that) 
;-)   and I was to learn almost all of the jobs done in the plant. Many of 
the bag making machines, especially the ones used for making the larger 
bags used "static bars" which I do not claim to understand as details of 
their innards was never really explained to me. They consisted of an outer 
brass shell which was a tube of about 1" diameter. The tube had a row of 
closely spaced maybe 3/4" holes down one side. Inside of the tube was a 
brass rod with a row of little sharp spikes like little lightning rods. 
That tube was mounted so that it ran as close as possible to the moving 
plastic film with the holes down toward the film. A heavily insulated small 
wire ran to a "black box" filled with all manner of components that I 
didn't recognize and on the bottom of the box was one or two sockets that 
held a 220 volt light bulb to serve as a ballast. As the machine operated 
the bulb(s) flickered and fluttered depending on the amount of static in 
the film. It was not there for operator protection but rather to prevent 
the static charged film from clinging together and jamming the machine. We 
also used a "tinsel" that was about 5/8" in diameter that looked like gold 
Xmas tree tinsel but was metal. We would often tie it across the moving 
film letting it slide on the surface and grounding it to the metal frame of 
the machine. Some of the guys would tie a piece of it around one ankle and 
let a foot of it drag on the concrete floor or tie a longer piece to the 
machine frame. I personally never felt that it did much good grounding 
people. In another department we unwound roll film onto big adjustable 
reels to cut it into various lengths up to around 10'. That old equipment 
was pretty crude and the rolls of film had a steel arbor shaft mounted 
through them and and were sat in simple notches in an oak 4" X 4" as 
bearings. There were crude metal collars used to keep the shafts in 
position lengthwise, one collar on each side of the oak support held by big 
square headed set-screws. The lower support was all steel and big bolts 
held the oak to the steel. As the film unrolled the head of the setscrew 
passed within about an inch and a quarter of one bolt head. With many rolls 
of film (mostly polyethylene) the static was so bad that a huge spark would 
jump from the setscrew to the bolt head every revolution. I got zapped "a 
LOT" in that department.   :-)
	Back in the 1950's most cars with vinyl seats had a little rubber ground 
strap hanging down underneath dragging on the ground an inch or two. The 
one on our 1952 Ford was about an inch wide and maybe 14" long with a clamp 
to hold it to the center of the car frame. I remember that it had a yellow 
lightning bolt printed on it and I believe it had fine wires molded into 
the rubber. I had several cars with those on them later. They did help but 
didn't always make a ground. I believe that J. C. Whitney still sells them.
Probably more than you wanted to know...   :-)


Footnote: It seems that under the right circumstances the human body is 
capable of holding a pretty good static charge for sometime after a lot of 
getting zapped. Diana soon learned not to kiss me when I got home until we 
had touched hands first to let the spark happen there. I must also confess 
to occasionally abusing the use of that charge when feeling playful... 
;-)




--
"farmer"


Francis Robinson
Central Indiana, USA
Robinson at svs.net