The march of technology can be seen in Mankind's quest to mark time. Throughout most of history, it was sufficient to see the general position of the sun in the sky during the day, or the position of the Big Dipper at night.
to a as . The on the of . to the hour and to hour the 's .
Ancients who were meticulous enough to want more invented the sun dial and tracked the shadow cast by a rod as the sun crossed the sky. The rate that a candle burned downward, drops of water from a water clock, or the grains of sand passing through the throat of an hour glass were improvements that worked on cloudy days.
The first mechanical clocks were invented in Medieval Europe; clever arrangements of gears and wheels that were made to turn by weights pulled downward by the force of gravity. They became common in churches and monasteries to call the faithful to prayers. They could strike bells but only had an hour hand and could gain or lose up to a half an hour per day.
No clock in existence, up through 1656, could measure short intervals of time accurately, or could possibly be relied on to tell time to the minute.
In the 1590's the Italian scientist Galileo measured the speed of falling bodies using his own pulse rate. His studies disproved the physics of Aristotle that had held for the previous eighteen centuries. His work laid the foundation for Isaac Newton's later laws of motion. As a teenager in 1582 Galileo had noticed the swinging chandeliers in a cathedral. It seemed to him that
Revision as of 23:07, 4 April 2012
This blog follows a project to build a legacy pendulum clock as an inspiration to engineering students. The case is modeled on the form of Georgia Tech's "Tech Tower" administration building. The highly visible clockwork mechanism inside this case includes actions to gong on the hour and to chime the quarter-hour with phrases from the school's "Rambling Wrech" fight song.
Tech Tower is the inspiration for the clock case. Early 2D and 3D modeling efforts are shown. Note that the pendulum and the full height of the clock case are not yet included.
This is a first full height view of the intended clock. Compared to the prior images, the scale of the case is shrunk to 75% so the escape wheel pallets are centered in the arch window behind the TECH lettering. The clock dial is at 64" up from the floor. The peak of the roof is at 108" (9-feet). Note this view shows using the image of the GT seal on the swinging pendulum bob.
Jim and Larry at the Royal Observatory in Greenwich, England in October 2006
Early 2D work on the regulator gear train (click on image to enlarge view)
Front view of the early regulator gear train and frame development
Early side view of the regulator gear train and frame
Early isometric view of the regulator gear train and frame
Early isometric view of the regulator gear train with front frame pieces removed
Close-up of the escape wheel area
Close-up of the great wheel area
The GT seal, planned to be used on the pendulum bob
Escape wheel laser cut profile (approx. 6" diameter)
72 tooth 10 DP gear laser cut profile (7.2" pitch diameter)
"Rambling Wreck" chime timing chart
1st Qtr = "I'm a rambling wreck"
2nd Qtr = "I'm a rambling wreck from Ga. Tech"
3rd Qtr = "I'm a rambling wreck from Ga. Tech and a hell of an engineer"
4th Qtr = "Rambling, gambling hell of an engineer" GONG, GONG, GONG, ...
An initial gear train layout (milled gears)
Prototype milled gears and escape wheel (for high-end clock)
Laser cut acrylic gear (low-end development work)
Early gear mesh prototype (masking tape holds frame together)
YouTube link http://www.youtube.com/watch?v=itsAtmS8PZA&feature=youtu.be
YouTube link to an animation http://www.youtube.com/watch?v=5fhZmld2q0A&feature=youtu.be
Early investigations into the chiming and gonging linkages