Hi All,

 

Here are links to a couple pictures of the latest incarnation of my
continuing experiment in recycling.
http://mit.midco.net/rpratt/images/Vertical.JPG    I started with optical
position sensing and moved to different coil and damping configurations.
The upper spring attachment is adjustable over about 4" in out up down. The
attachment to the carbon fiber boom was also initially adjustable but is now
in place for the current 2.68 second period.  I have experimented with
periods of 1 to 4.5 seconds.  I cast the lead mass which has the vertical
damping vane integral and a brass bolt threaded into it for fine balance
adjustments. http://mit.midco.net/rpratt/images/CoilDamp.JPG  Damping is
adjustable by turning the damping magnets on threaded attachment bolts to
set the gap between the 2 sides.  I tried a knife edge pivot and found it
basically worthless so now have a flex pivot in compression.  The main frame
is 3/16" by 1 1/2" steel angle brazed together.  The magnet has an extension
to the center pole into the coil and the outer pole face is removed to
prevent shortcut of field below the coil.  

 

I like the steel angle construction for simplicity and quick assembly.  I
like the damping system as the force lines are not offset and damping is
easily tuned to a fine level and not easily bumped out of adjustment.  The
damping system is also fixed to the frame so it does not pick up separate
vibrations.  The solenoid type coil set up is very sensitive.  The change
from knife edge to flex is a must for anyone contemplating construction.  In
the future I may try the optical position system as a feedback loop but it
did not compare in sensitivity to the coil. 

 

I realize I don't have a laboratory instrument here but in the past I have
loaned my horizontal to local schools and learned lessons about durability.
This instrument works, is durable for hands on and is easy to move and
adjust.  Total cost is basically that of the spring.

 

Randy 

 

 

 

Randall L. Pratt

Youth for Understanding Area Representative














Hi =
All,

 

Here are links to a =
couple
pictures of the latest incarnation of my continuing experiment in
recycling.  http://mit.midco=
..net/rpratt/images/Vertical.JPG
   I started with optical position sensing and moved to
different coil and damping configurations.  The upper spring =
attachment is
adjustable over about 4" in out up down. The attachment to the =
carbon
fiber boom was also initially adjustable but is now in place for the =
current
2.68 second period.  I have experimented with periods of 1 to 4.5
seconds.  I cast the lead mass which has the vertical damping vane
integral and a brass bolt threaded into it for fine balance adjustments. =
http://mit.midco=
..net/rpratt/images/CoilDamp.JPG
 Damping is adjustable by turning the damping magnets on threaded
attachment bolts to set the gap between the 2 sides.  I tried a =
knife edge
pivot and found it basically worthless so now have a flex pivot in =
compression. 
The main frame is 3/16" by 1 1/2" steel angle brazed =
together. 
The magnet has an extension to the center pole into the coil and the =
outer pole
face is removed to prevent shortcut of field below the coil.  =


 

I like the steel =
angle
construction for simplicity and quick assembly.  I like the damping =
system
as the force lines are not offset and damping is easily tuned to a fine =
level
and not easily bumped out of adjustment.  The damping system is =
also fixed
to the frame so it does not pick up separate vibrations.  The =
solenoid
type coil set up is very sensitive.  The change from knife edge to =
flex is
a must for anyone contemplating construction.  In the future I may =
try the
optical position system as a feedback loop but it did not compare in
sensitivity to the coil. 

 

I realize I =
don’t have
a laboratory instrument here but in the past I have loaned my horizontal =
to
local schools and learned lessons about durability.  This =
instrument works,
is durable for hands on and is easy to move and adjust.  Total cost =
is
basically that of the spring.

 

Randy =


 

 

 

Randall L. Pratt

Youth for Understanding Area =
Representative