A History of Mechanical Clocks
A clock is defined as an instrument to measure, keep, and indicate the time. Clocks are one of humanity’s oldest inventions and they meet a need to measure intervals that are shorter than natural units of say, a day, lunar month, or year. Many devices operating under several physical processes have been used over the centuries, however traditionally the term ‘clock’ was reserved for striking clocks only, anything else was called a timepiece. Nowadays the term ‘clock’ refers to any device for measuring and displaying the time and they have seen some innovations.
Water clocks have been covered in our previous article so we thought it best to start with the advent of newer technology and therefore begin with mechanical clocks. The first mechanical clocks were designed in the early 14th century with the invention of the verge escapement mechanism, a type of escapement which is common to many timepieces. Further mechanisms would later be designed such as spring-driven clocks, pendulum clocks, and electric clocks, all of which brought their own style, which we will cover below:
Early Mechanical Clocks
Designed in Europe sometime between the late 13th and early 14th century early mechanical clocks made use of an escapement device to regulate the release of power through a timekeeping device. Whereas early clocks relied on water power it is thought early mechanical clocks made use of power derived from falling weights and this power release may have been controlled by oscillating mechanisms such as bell-ringing or alarm devices.
The invention of the verge escapement made the development of all mechanical clocks possible whereas previously time was measured by a continuous process, such as the shift of sand, or flow of water, it now became of process of measuring oscillations in the controlled release of power, for example as seen in the later developed pendulum clock.
Early mechanical clocks were used for signaling and notification, such as the timing of services and public events, and modeling the solar system. Many simple clocks were installed in towers and did not require faces or hands – they simply announced the hours or intervals between events. More complicated clocks, however, did have faces and hands.
Spring Driven Clocks
As mentioned the escapement of a clock was of significant importance to their development and clockmakers soon found the escapement was an important factor in the clock’s accuracy. Building clocks became a technical challenge, and many mechanisms were designed, including the spring-driven clocks which appeared in the 15th century. Technical challenges had to be overcome to keep the rate at which the clock moved constant as the spring ran down.
A crucial development to the spring-driven clock was the development of a spiral balance spring in the 17th century. Known as a hairspring, this device controlled the oscillating speed of the escapement. This revolutionised clocks as it allowed the development of timepieces on a much smaller scale when innovators were able to use the design successfully in pocket watches.
Pendulum clocks were invented just prior to the spiral balance spring, in the mid 17th century. Based on the idea that a swinging bob could regulate the motion of a time-telling device this clock required mathematical calculations to determine how pendulum length related to time. With a pendulum length of 99.4cm determined to equate to 1 second of movement, the first pendulum clock was made. These clocks were popularised by the longcase clock, better known as a grandfather clock.
Originally designed in the early 19th century, early electric clocks made use of batteries and an electric current to power a motor or electromagnet so as to wind a mainspring. ‘Electromechanical clocks’ would be the term given to clocks that used a mixture of either AC or DC current to rewind the spring or raise the weight mechanism for an otherwise mechanical clock. Later, electrical clocks would be designed which would use the oscillations of either the AC power source, a tuning fork, or quartz crystal to measure time.
Where quartz has been used as the timekeeping device these clocks were known as quartz clocks, in the same way that we now have quartz wristwatches. Science has taken things even further now by using atoms on an atomic level as the oscillation device, measurable with advanced technology. These clocks, known as atomic clocks, are the most accurate we have to date and deserve their own article to be published later. Just for an idea though, an atomic clock can be accurate within a few seconds over a trillion years!
We hope you enjoyed this article on the history of clocks. Stay with us for more at Boutique Von Burg.