Grandfather Clocks for Home

How Grandfather Clocks Work

In my article ‘Grandfather Clock Functionality’, I began the discussion with two internal workings of Grandfather Clocks, the Pendulum, and Escapement Mechanisms. These are an active part of the beautiful chimes as well as the timekeeping.

I would like to delve further into the internal workings of Grandfather Clocks, and all mechanical clocks as well.

“As I have discussed in another article, some of the earlier long case clocks (Grandfather Clocks) had a pendulum arch of 100 degrees. Long pendulums with such wide swings were in large open clocks usually displayed outside. With the invention and use of the anchor escapement mechanism was able to reduce the pendulum swing radius to 4 to 6 degrees. The introduction of longcase or grandfather clocks is due to the invention of the anchor escapement mechanism.” From ‘Grandfather Clock Functionality’

As you can see, longcase Grandfather Clocks are connected to both the anchor escapement and the functioning of the Pendulum.

The functioning of the Pendulum in Grandfather Clocks is much more complicated than I first thought. (Perhaps you could care less, but it is rather interesting.)

“Most of these clocks had short pendulums to be contained within a case. As advances were made in escapement mechanisms, clockmakers were able to use longer pendulums, which had slower “beats,” but maintained the shorter swing radius. These needed less power to keep going. They had less friction and wear in the movement, and were more accurate.” From ‘Grandfather Clock Functionality’

These changes came with the deadbeat escapement mechanism, as and improvement over the anchor escapement. Are you beginning to see how historical improvements and the mechanics Grandfather Clocks work together?

The Pendulum and Longcase Grandfather Clocks

Today, I went back over my notes on the the Pendulum as a mechanism in Grandfather Clocks, which brought me to the ‘Gravity Pendulum.’

The simple gravity pendulum was initially aggrandized, ignoring its deficiencies. It is a weight (which is otherwise called a ‘bob’ – See ‘Grandfather Clock Terms’) on the end of a cord/rod (having no substance), and is suspended from a pivot/fulcrum (on which an object turns/pivots; specifically a metal pointed pin or short shaft in machinery, as at the end of an axle). This model assumes that the pendulum swings freely in the longcase of Grandfather Clocks, and that there is no friction, which is impossible. We will get to friction and drag later.

When the gravity pendulum in Grandfather Clocks is given a push (power source / chain drive) from its center or resting position, there is a restoring natural force exerted upon the pendulum, gravity. As the pendulum swings, gravity is exerting force to return the pendulum to its original position of equilibrium. The restoring force combined with the actual mass (size, weight, shape) of the pendulum results in oscillation. The pendulum swings back and forth to and past the point on equilibrium. (Oscillation is the swing back and forth.) The period of time it takes for a pendulum in Grandfather Clocks to swing back and forth both is dependent upon the length of the Pendulum.

Galileo Galilei (See ‘Grandfather Clocks, Famous Clockmakers’) discovered (in the early 1600s) that the regular swing of a pendulum was useful in timekeeping. It remained the world’s most accurate timekeeping technology until the 1930s.

“Galileo had the idea for a pendulum clock in 1637, and it was partly constructed by his son in 1649, neither lived to see their idea in operation. The Pendulum Clock, invented in 1656 by Dutch scientist Christiaan Huygens, and patented the following year, was inspired by investigations of pendulums by Galileo Galilei beginning around 1602.” From ‘A Pendulum Clock’

Much later this clock was named one of the many beautiful Grandfather Clocks.

Pendulums are used to regulate pendulum clocks, which are Grandfather Clocks / mechanical clocks. They can also be found in scientific instruments such as seismometers. They have been utilized in measuring the acceleration of gravity in geophysical surveys. (Gravity differs at differing points on the earth’s surface.)

In actuality, the pendulums in our Grandfather Clocks are subject to mechanical friction and air drag, so the amplitude of their swings declines over time and space.

All the following factors are considered in the calculations for the oscillation of the pendulum:

Air density

Humidity

Heat

Mass of the string/cord/strap/tube

The size and shape of the bob

How the bob is attached to the string

Flexibility and stretching of the string

Motion of the support

Types of metals used in the construction of the mechanical parts

Local gravity

The Pendulum in longcase Grandfather Clocks is a harmonic oscillator. For more information that is specific to this area, review the article ‘A Pendulum Clock’ and review Harmonic Oscillator in ‘Grandfather Clock Terms’.

I great deal of mathematical study and experimentation went into the ultimate creation of Grandfather Clocks.

There is more to come in the next week or two on How Grandfather Clocks Wrok. As I review all my notes and other article, I will publish more on this new updated article on the ‘How Grandfather Clocks Work’. This current section will be updated and the following sections will be added: The Accuracy of Pendulums as Timekeepers, Reasons for the Pendulum Size and Shape, and ‘Pendulums in Mechanical Clocks’.

At the end of the full article, you will find a listing of resources for locating the information I discovered on ‘How Grandfather Clocks Work’. I find that my local Reference Librarian is a reliable help in ferreting out information on Grandfather Clocks. In addition, Wikipedia is a good place to start.

Have a Great Day!