PSN-L Email List Message

Subject: Re: Short period spring vertical lower pivot question
From: Robert Thomasson rlthomasson@.........
Date: Mon, 13 Jul 2009 22:36:59 +0300


Meredith, there was an extra "r" typo in your myelectric.info link.  The
corrected  link is below (I think)

http://www.myeclectic.info/SeismoPivots/seismopivots.htm




On Mon, Jul 13, 2009 at 10:05 PM, meredith lamb wrote:

> Hi all,
>
> BACKGROUND PIVOT:  Chris Chapman's newer horizontal designs with his lower
> pivot being a boom end flat that is pivoting on a mast mounted
> ball bearing seems to be a very ideal, reliable and much more stable
> "standard pivot" for those of us endeavoring  to make a commonly used home
> brew horizontal seismometer.  It was studied in 2008 by him, Charles Patton
> and Brett Nordgren and briefly described by the web paper:
> http://www.myeclectric.info/SeismoPivots/seismopivots.htm   and had many
> other PSN description emails in that time period.
>
> The question that comes up from all this is whether such a lower pivot/s
> could be ~ reliably used in a home brew short period vertical
> spring seismometer?  I note no reference to such a trial; but that doesn't
> exclude that someones hasn't already experimented with such?
> This excludes known boom mounted balls on a mast flat.  The size/weight of
> the seismometer mass in mind is similar to that of the AS1.
>
> I would also assume that it is likely necessary to have any such balls
> mounted on the side of a mechanical support/s to fix the spring opposition.
>
> It would necessitate two such pivots for maintaining vertical positional
> reliability...i.e.; the "boom" would need to be "T" shaped to constrain
> its otherwise undesirable lateral movement with only one pivot.
>
> Meredith Lamb
>
>
>
>
>
>
>
>
>
>
>
Meredith, there was an extra "r" typo in your myelectric.info link.=A0 The corrected=A0 link is below=
 (I think)

http://www.myeclectic.info/SeismoPivots/seismopivots.htm



On Mon, Jul 13, 2009 at 10:05 PM, me= redith lamb <paleoartifact@.........> wrote:
Hi all,
=A0
BACKGROUND PIVOT:=A0 Chris Chapman's newer horizontal designs with= his lower pivot being a boom end flat that is=A0pivoting on a mast mounted=
ball bearing seems to be a very ideal, reliable and much more stable &= quot;standard pivot" for those of us endeavoring=A0=A0to make a common= ly used=A0home
brew horizontal seismometer.=A0 It was studied in 2008 by him, Charles= Patton and Brett Nordgren and=A0briefly described by the web paper:=A0 http://www.myeclectric.info/SeismoPivots/seismopivots.htm= =A0=A0 and had many other PSN description emails in that time period.
=A0
The question that comes up from all this is whether such a lower pivot= /s could be=A0~ reliably used=A0in a home brew short period vertical
spring seismometer?=A0 I note no reference to such a trial; but that d= oesn't exclude that someones hasn't already experimented=A0with=A0s= uch?
This excludes known boom mounted balls on a mast flat.=A0 The size/wei= ght of the seismometer mass in mind is similar to that of the AS1.
=A0
I would also=A0assume that it=A0is likely=A0necessary to have any such= balls mounted on the side of a mechanical support/s to=A0fix the spring op= position.
=A0
It would necessitate two such pivots for=A0maintaining vertical positi= onal reliability...i.e.; the "boom"=A0would need to be "T&qu= ot; shaped to constrain
its otherwise undesirable lateral movement with only one pivot.=A0
=A0
Meredith Lamb
=A0
=A0
=A0
=A0
=A0
=A0
=A0
=A0
=A0
=A0


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