Grandfather Clocks, Mechanical Clocks

Grandfather Clocks for Home

Grandfather Clocks and Mechanical Clocks

People have been keeping track of time throughout the ages using everything from hourglasses to sundials. (See ‘Grandfather Clock History’) To continue with the progress of mechanical clocks, we will retrace some of our steps from the previous article, ‘The History of the Grandfather Clock.’

Between 500 and 1500 A.D. (The Middle Ages-The 6th to 16th centuries – Europe) progress in timekeeping was limited. Sundials were placed above doorways, but could only be used on sunny days. Are you ready for this? Pocket sundials were developed. In the 10th century, sundials could identify tides and take into account changes of the seasons.

“Galileo was first credited with the discovery that a pendulum could be used to keep time. This led to Dutch scientist Christiaan Huygens developing the first pendulum clock, the prototype for the grandfather clock.” In the 1300’s, bulky mechanical clocks began to appear in the towers of several large Italian cities. Keep in mind that these early mechanical clocks were the predecessors of Grandfather Clocks. These mechanical clocks kept time for more than 300 years. Of course, there were variations and improvements along the way.

These ancestors of Grandfather Clocks had a basic problem. The time it took for the swinging (oscillation) of the pendulum (See A Pendulum Clock article: Part 1 – 3), which is part of the escapement mechanism (See Grandfather Clock Terms). The force behind the movement and friction played a large role in the accuracy of these clocks. Similarly, to the early water clocks, these early mechanical clocks were difficult to regulate.

Accurate Mechanical Clocks and Grandfather Clocks:

Again, “Galileo was first credited with the discovery that a pendulum could be used to keep time. This led to Dutch scientist Christiaan Huygens developing the first pendulum clock, the prototype for the grandfather clock.” (1656) Galileo Galilei studied the motion of the pendulum as early as 1582; his designs were never built.
Huygens’ The pendulum clocks (Mechanical Clocks / Grandfather Clocks) of Huygens’ were accurate to 1 minute a day. Ultimately, he improved on his design to reduce errors to less than 10 seconds a day!
William Clement introduced further improvements. He built pendulum clocks with an improvement over the verge escapement (1671), the anchor escapement (recoil escapement). There was less motion in the swing of the pendulum.
George Graham (1721) improved the mechanical pendulum clock’s accuracy down to a variation of 1 second per day. This was accomplished by balancing the length of the pendulum’s length with changes in temperature.
John Harrison (See ‘Grandfather Clocks, Famous Clockmakers… ) advanced Graham’s “temperature compensation techniques,” adding new means for reducing friction even further. In 1761 he had built a marine chronometer, which kept time on board a rolling ship to about one-fifth of a second a day.
In 1889 Siegmund Riefler’s clock had a nearly ‘drag’ free pendulum. This pendulum clock’s accuracy was a hundredth of a second a day. His work develop into the standard for many astronomical observatories.
The free-pendulum principle was launched by R. J. Rudd (1898) inspiring the further advancement of many more free-pendulum clocks.
A free-pendulum clock (W. H. Shortt clock) was demonstrated in 1921. The Shortt clock was far superior to the Rudd clock and became the ‘supreme timekeeper in many observatories.’ The Shortt clock had two pendulums, one being the slave, and the other a master pendulum. The slave pendulum drives the clock hands; it also gives the master pendulum a gentle push to maintain the motion of the master pendulum. This relieves the master pendulum of its previous duties of any mechanical tasks, thus improving accuracy.