Taken with a Canon T3I and Canon 60mm Macro
gear ratios are chosen to convert the time counted by the escape wheel into minutes and hours. For a 30 tooth, 60 second escape wheel a 60:1 ratio is needed to count 60 minutes for one hour. Then to count 12 hours, a 12:1 ratio is needed. Below, the 9:78 and 13:90 gear train produces a 60:1 ratio. Note that the intermediate ratios are not integer values. It may seem more intuitive to choose a train with a 15:1 followed by a 4:1 to get 60:1, but a gear train with non-integer ratios will produce more even wear on the teeth over the lifetime of the clock. I wrote a program to search all gear combinations over a given set of restrictions to produce the values shown below. It took less than 60 seconds to search about 2 million combinations and was written in Java.
A gear is a rotating machine part having cut teeth, or cogs, which mesh with another toothed part in order to transmit torque. Two or more gears working in tandem are called a transmission and can produce a mechanical advantage through a gear ratio and thus may be considered a simple machine. Geared devices can change the speed, torque, and direction of a power source. The most common situation is for a gear to mesh with another gear; however, a gear can also mesh with a non-rotating toothed part, called a rack, thereby producing translation instead of rotation.
How a Pendulum Works:
A pendulum is made up of a string or solid rod with a weight attached to the end. Pendulums are designed in such a way that once they are moved, they will continue to swing for a long period of time. Gravity is the force that keeps the pendulum moving. Pendulums are often used in clocks because it takes the same amount of time for it to swing in one direction as it does for it to swing in the other direction. The amount of time it takes for a pendulum to swing from one side to the other and back again is called a �period.� A pendulum whose period is 4 seconds takes 2 seconds to swing to the left and 2 seconds to swing back to the right.
How a Mechanical Clock Works:
Mechanical clocks tell time using gears. They have two important parts: a mainspring and a pendulum. Mechanical clocks are wound with a key, and this tightens the mainspring. As the mainspring unwinds, its energy turns gears which cause the hands to move. The pendulum keeps time and ensures that the gears move at the right pace: second by second. Instead of a mainspring, some mechanical clocks have weights that pull the gears at the right pace. Mechanical clocks do not need electricity to operate. They can run off of the energy generated by their springs and weights.