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, TedHow would a seismic wave, passing by an = inverted T=20 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 LehmanSent: Saturday, December 15, = 2007 2:56=20 PMSubject: Re: Anniversary clock=20 springTed--there is some neat physics in = the inverted T=20 torsional balance. The increase of period with increased masses = added=20 makes for a nice graph in a physics lab, and there are related aspects = of=20 interest. Perhaps stability would be a big problem, but set it = up with a=20 damping mechanism, and give it a=20 try. Seasons=20 Greetings Jim Lehman----- Original Message -----From:=20 tchannel1@............ =To: psnSent: Saturday, December 15, = 2007 1:40=20 PMSubject: Anniversary clock = springHi 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 to=20 wind it once a year, or so. I know very little about = clocks, but=20 have worked on a few clock movements and escapements. I = have=20 some old clocks which are 8 day movements. I wondered = why the=20 big difference in power consumptions, and spring properties between = the two=20 types.
The 8 day movements use a short pendulum which is maybe 1/2=20 second natural period. The anniversary clock has a short = spring,=20 instead of a pendulum, which is like a flat thread. This = spring=20 is fixed at the top and has four masses, brass balls on the free = end. =20 One period of this spring is about 8 seconds. The = mass in=20 motion, twist the thread like spring, until the power of the spring = stops=20 the mass, and swings it in the opposite direction. A = different=20 coiled mainspring then add a kick to the mass and the cycle=20 repeats.
Always looking for different ways to obtain a 20 second period, I = took a=20 band saw blade, cut it and suspended it from my shop ceiling. = It now=20 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 a=20 mass to both ends of the yardstick. I twisted the spring and = released=20 it. I found it rotated back and forth and it period was = about 8=20 seconds. I keep adding equal mass to both end of the = yardstick, and=20 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, = Ted