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 =
doesn't add much.

     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
  especially the adjustable period (amazing)!    It "reads" to =
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.html
Take=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 =
doesn't add=20
    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
    

    

    =