## PSN-L Email List Message

Subject: Re: Crossed wire mass pendulum signal extension/s
From: tchannel1@............
Date: Sat, 20 Sep 2008 08:06:45 -0600

```Hi Folks,  This is one approach I have not tried.  =
http://www.phy.mtu.edu/~suits/PH3110/pendulums.html
Has anyone built one, as a mock up to see the results?
If someone would suggest some dimensions, I would like to try it, to see =
how it would work and the period possible.
Ted
----- Original Message -----=20
From: meredith lamb=20
To: psn-l@.................
Sent: Friday, September 19, 2008 9:24 PM
Subject: Re: Crossed wire mass pendulum signal extension/s

Hi Charles,

The X-suspension sounds most interesting; especially the adjustable =
period (amazing)!    It "reads" to be ~ similar to the=20
crossed wire pendulum at this URL below; but different; with the =
adjustable mass in between the plates, and, both plates are
"X" suspended. =20

http://www.phy.mtu.edu/~suits/PH3110/pendulums.html

Take care, Meredith

On Fri, Sep 19, 2008 at 12:43 PM, Charles Patton =
wrote:

Meredith,
We're (Brett, Chris and I) putting the finishing touches on a white =
paper on pivots with spreadsheet calculations of actual locus points, =
errors, etc. that shortly I'll put up on a web site.  It includes your =
pivot that I'm calling the X-roll.  It's problem is that it doesn't have =
an easy way of obtaining long periods except the use of  force feedback =
at which point I would argue that the lever arm extension probably =

I toss out an alternate idea.  The paper will include the equations =
for something I'm calling the X-suspension that comes from work on LIGO. =
It's essentially two flat plates suspended with crossed wires and a =
mass attached to the lower plate and adjusted in height between the the =
plates. This can be set for any period.  It would have the property you =
mention, so a lever arm attached to the bottom plate and extended away =
from the bottom would magnify the movement.  I haven't done it yet, but =
it seems to me that although for the LIGO work they used flat flexures =
with traditional clamps, the scheme is very amenable to use of rolls and =
wire or bands for very low friction.  I think it could be accomplished =
with 3 bands minimum, but 4 equal width bands would make construction =
easier and very high Q.

Regards,
Charles Patton

Hi Folks,  This is one approach I =
have not=20
tried.  http://www.phy.mtu.edu/~suits/PH3110/pendulums.html
Has anyone built one, as a mock up to =
see the=20
results?
If someone would suggest some =
dimensions, I would=20
like to try it, to see how it would work and the period =
possible.
Ted

----- Original Message -----
From:=20
meredith lamb
To: psn-l@..............
Sent: Friday, September 19, =
2008 9:24=20
PM
Subject: Re: Crossed wire mass =
pendulum=20
signal extension/s

Hi Charles,The X-suspension sounds most =
interesting;=20
be ~=20
similar to the crossed wire pendulum at this URL below; but =
different;=20
with the adjustable mass in between the plates, and, both plates =
are"X"=20
suspended.  http://www.phy.mtu.edu/~suits/PH3110/pendulums.htmlTake=20
care, Meredith
On Fri, Sep 19, 2008 at 12:43 PM, Charles =
Patton <charles.r.patton@........> wrote:
Meredith,We're=20
(Brett, Chris and I) putting the finishing touches on a white paper =
on=20
pivots with spreadsheet calculations of actual locus points, errors, =
etc.=20
that shortly I'll put up on a web site.  It includes your pivot =
that=20
I'm calling the X-roll.  It's problem is that it doesn't have =
an easy=20
way of obtaining long periods except the use of  force feedback =
at=20
which point I would argue that the lever arm extension probably =
much.

I=20
toss out an alternate idea.  The paper will include the =
equations for=20
something I'm calling the X-suspension that comes from work on LIGO. =

It's essentially two flat plates suspended with crossed wires =
and a=20
mass attached to the lower plate and adjusted in height between the =
the=20
plates. This can be set for any period.  It would have the =
property you=20
mention, so a lever arm attached to the bottom plate and extended =
away from=20
the bottom would magnify the movement.  I haven't done it yet, =
but it=20
seems to me that although for the LIGO work they used flat flexures =
with=20
traditional clamps, the scheme is very amenable to use of rolls and =
wire or=20
bands for very low friction.  I think it could be accomplished =
with 3=20
bands minimum, but 4 equal width bands would make construction =
easier and=20
very high Q.Regards,Charles Patton

=

```