The history of Time keeping
(Collected from various sources on the internet)
The first real means of telling time with clocks appear to have been devised by the Egyptians. By 2100 BC, they had invented a means to divide the day into 24 hours. They used sundials or shadow clocks to measure the time of day. The Sundial indicates the time of day by the positioning of the shadow of some object on which the sun's rays fall. The shadow clock consists of a straight base with a raised crosspiece at one end. A scale with time divisions is inscribed on the base. The clock is set east-west and is reversed at midday.
By 1500 BC, the Egyptians had found a more accurate way to tell time. This method was the water clock, (also known as a clepsydra). This clock uses the steady dripping of water from a vessel to drive a mechanical device that tells the time. These clocks were used for nearly 3,000 years and grew more and more sophisticated. Water clocks were designed that rang bells, moved puppets and even caused mechanical birds to sing! (Now you know where a cuckoo clock came from.)
As you may know, all mechanical clocks must have some source of energy, be it a falling weight, a spring, a battery or even an atom. What ever method, it must be carefully designed and regulated in order for the clock to be accurate. The earliest mechanical clocks used a weight to drive it.
The first major advance in clock construction occurred in Europe during the 14th century. It was found that the speed of a falling weight could be controlled by using a oscillating horizontal bar attached to a vertical spindle with two protrusions on it which acted like escapements, (cliff like ridges). When the protrusions meshed with a tooth of a gear driven by the weight, it momentarily stopped the revolving wheel and weight. These oldest type of mechanical clocks can still be seen in France and England.
Although fairly accurate, these clocks were dramatically improved by the introduction of the pendulum. The pendulums swinging ensures that the protrusions move the gears wheels tooth by tooth while the motion of the protrusions keeps the pendulum moving. It was improved further by the Englishmen Robert Hooke who invented the anchor or recoil escapement. This improved the functioning of the gear train. Infact, this method is still used today. The greatest benefit of this method was that it allowed for very long pendulums with a swing of one second. The out growth of this invention was the walled pendulum clock where the weights and pendulum are completely enclosed in a case. Of course, most people are very familiar with these clocks with the most common being the 'Grandfather Clock'.
Near the end of the 15th century, the spring had begun to replace the weight in some clocks. This advancement allowed for clocks which could be carried. One problem with a spring clock is that the escapement mechanism must always be operated with a constant force. The problem was that as the spring unwound, it lost power. To solve this, the stackfreed was introduced. This is an extra spring that works against the motion when the watch is fully wound.
During the 16th and 17th centuries the need for accurate clocks while sailing across the oceans arose. While springs made clocks portable, they were not accurate for long periods. Hooke realized that a spring would not be affected by the ship's motion as a pendulum would, but the available mainspring devices were not accurate enough for long periods of time until 1675, when the balance wheel, a very thin spiral hairspring (separate from the mainspring) whose inner end was secured to the spindle of a rotatable balance and whose outer end was fixed to the case of the timepiece. The spring stored or released energy during the rotation of the balance. John Harrison's chronometer no. 4, was in error by only 54 seconds after a sea voyage of 156 days.
The balance wheel, hairspring, and mainspring, together with the anchor escapement, or improved escapements, still make up the basics of even todays modern watches. Introduction of jewels as bearings have further improved on this basic system. Watches run by small batteries were introduced in the 1950s. The balance of such an electric watch is kept in motion electromagnetically by a coil that is energized by an electronic circuit. The modern electronic watch is driven by a quartz crystal, which is made to vibrate at its natural frequency. The latest digital quartz watches display time in numbers, using LEDs (light-emitting diodes) or an LCD (liquid-crystal display).
The latest invention to tell time and by far the most accurate are atomic clocks, which measure time in terms of the oscillations of cesium, nubidium, hydrogen, or other elements. Such clocks may be accurate to within 1 second in many thousands or even millions of years.
While our history is not as long as that of the clock, Theisen Clock & Novelty has a commitment to and a history of courteous service, quality craftsmanship and prompt delivery.