Les, I think some of the others may answer this better than me, but I =
would suspect this would act the same as other sensors:
The movement of the earth resulting from an earthquake, will move the =
entire apparatuses, and the room it is in. However the mass at the ends =
of the inverted T will move less, relative to the sensor and the room it =
is in.
Ted
----- Original Message -----=20
From: Les LaZar=20
To: psn-l@.................
Sent: Saturday, December 15, 2007 5:01 PM
Subject: Re: Anniversary clock spring
How would a seismic wave, passing by an inverted T torsional balance, =
impart any torsional motion to the horizontal bar and the masses? Just =
wondering.
Les LaZar
----- Original Message -----=20
From: Connie and Jim Lehman=20
To: psn-l@.................
Sent: Saturday, December 15, 2007 2:56 PM
Subject: Re: Anniversary clock spring
Ted--there is some neat physics in the inverted T torsional balance. =
The increase of period with increased masses added makes for a nice =
graph in a physics lab, and there are related aspects of interest. =
Perhaps stability would be a big problem, but set it up with a damping =
mechanism, and give it a try. Seasons Greetings Jim Lehman
----- Original Message -----=20
From: tchannel1@...............
To: psn=20
Sent: Saturday, December 15, 2007 1:40 PM
Subject: Anniversary clock spring
Hi Folks, This is an observation and a question. I have an =
Anniversary clock, perhaps also called a 500 day clock, as you only need =
to wind it once a year, or so. I know very little about clocks, but =
have worked on a few clock movements and escapements. I have some old =
clocks which are 8 day movements. I wondered why the big difference in =
power consumptions, and spring properties between the two types.
The 8 day movements use a short pendulum which is maybe 1/2 second =
natural period. The anniversary clock has a short spring, instead of a =
pendulum, which is like a flat thread. This spring is fixed at the top =
and has four masses, brass balls on the free end. One period of this =
spring is about 8 seconds. The mass in motion, twist the thread like =
spring, until the power of the spring stops the mass, and swings it in =
the opposite direction. A different coiled mainspring then add a kick =
to the mass and the cycle repeats.
Always looking for different ways to obtain a 20 second period, I =
took a band saw blade, cut it and suspended it from my shop ceiling. It =
now hangs similar to the thread like movement spring of the anniversary =
clock. At the bottom of the 72" band saw blade, I attached a 36" =
yardstick. This now looks like an inverted "T". I added a mass to =
both ends of the yardstick. I twisted the spring and released it. I =
found it rotated back and forth and it period was about 8 seconds. I =
keep adding equal mass to both end of the yardstick, and the period was =
24 seconds.
The yardstick seems to always come to rest at the same point, as =
the spring wants to untwist.
My question: Has anyone tried this approach? If so, could =
anyone direct me to more information about it on the internet?
Thanks, Ted
Les, I think some of the =
others may=20
answer this better than me, but I would suspect this would act the same =
as other=20
sensors:
The movement of the earth resulting =
from an=20
earthquake, will move the entire apparatuses, and the room it is =
in. =20
However the mass at the ends of the inverted T will move less, relative =
to the=20
sensor and the room it is in.
Ted
----- Original Message -----
From:=20
Les=20
LaZar
Sent: Saturday, December 15, =
2007 5:01=20
PM
Subject: Re: Anniversary clock=20
spring
How would a seismic wave, passing by =
an inverted=20
T torsional balance, impart any torsional motion to the horizontal bar =
and the=20
masses? Just wondering.
Les LaZar
----- Original Message -----
From:=20
Connie and=20
Jim Lehman
Sent: Saturday, December 15, =
2007 2:56=20
PM
Subject: Re: Anniversary =
clock=20
spring
Ted--there is some neat physics in =
the inverted=20
T torsional balance. The increase of period with increased =
masses=20
added makes for a nice graph in a physics lab, and there are related =
aspects=20
of interest. Perhaps stability would be a big problem, but set =
it up=20
with a damping mechanism, and give it a=20
try. Seasons=20
Greetings Jim Lehman
----- Original Message ----- =
From:=20
tchannel1@............ =
To: psn
Sent: Saturday, December =
15, 2007=20
1:40 PM
Subject: Anniversary clock=20
spring
Hi Folks, This is an observation and a question. I =
have an=20
Anniversary clock, perhaps also called a 500 day clock, as you =
only need=20
to wind it once a year, or so. I know very little =
about=20
clocks, but have worked on a few clock movements and=20
escapements. I have some old clocks which are 8 day=20
movements. I wondered why the big difference in power=20
consumptions, and spring properties between the two types.
The 8 day movements use a short pendulum which is =
maybe 1/2=20
second natural period. The anniversary clock has a =
short=20
spring, instead of a pendulum, which is like a flat =
thread. =20
This spring is fixed at the top and has four masses, brass balls =
on the=20
free end. One period of this spring is about 8=20
seconds. The mass in motion, twist the thread like =
spring,=20
until the power of the spring stops the mass, and swings it in the =
opposite direction. A different coiled mainspring =
then add=20
a kick to the mass and the cycle repeats.
Always looking for different ways to obtain a 20 second period, =
I took=20
a band saw blade, cut it and suspended it from my shop =
ceiling. It=20
now hangs similar to the thread like movement spring of the =
anniversary=20
clock. At the bottom of the 72" band saw blade, I attached a =
36"=20
yardstick. This now looks like an inverted "T". =
I added=20
a mass to both ends of the yardstick. I twisted the spring =
and=20
released it. I found it rotated back and forth and it =
period=20
was about 8 seconds. I keep adding equal mass to both end of =
the=20
yardstick, and the period was 24 seconds.
The yardstick seems to always come to rest at the same =
point, as=20
the spring wants to untwist.
My question: Has anyone tried this approach? =
If so,=20
could anyone direct me to more information about it on the=20
internet?
Thanks,=20
Ted
=