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Automatic Stop Watch – The History and How it Works

An automatic stop watch (or “mechanical stop watch”) is a watch that makes use of automatic mechanisms in determining time passage, in opposite to quartz stopwatches which functions electronically. Automatic stopwatches are driven by “mainsprings” and its force is transmitted in a range of gears to upgrade the balance wheel.

Similar to quartz stopwatches, the mechanical ones can be quite accurate depending on the manufacturer. However, the automatic stop watch can be expensive. Mechanical stopwatches are often worn as a visual attribute, accessory or simply a statement of individual style.

The Automatic Stop Watch Was Born

Peter Henlein is considered as the father of mechanical stopwatches. He was the first person to invent the “Nuremberg Egg” and “Pocket Watch”. Although both were invented in 1510, it was only in the 19th century when they were introduced.

The 1960s became a significant decade for production of stopwatches, since this was where the Quartz Revolution took place. Back then, all timepieces were deemed mechanical. Early creations meanwhile were appallingly imprecise – like a good quality watch can vary for about 15 minutes per day.

The method of “Modern Precision” (a few seconds for each day) was not attained by any timepiece until John Harrison invented his own Marine Chronometer in 1760. Modern Precision was only attained later in 1854 when Watcham Watch Co. pioneered the industrialization of manufacturing mechanical stopwatches.

How the Automatic Stop Watch Works

The mechanical automatic stop watch is considered a “mature technology”, and all ordinary timepiece movements have the same parts as that of the quartz ones.

The spiral-like mainspring powered by the stopwatch is attached inside the cylindrical barrel. The latter has a “gear teeth” found on the exterior part and turns the “center wheel” once every hour. The center wheel on the other hand controls the “third wheel”. The “fourth wheel” drives both the third and center wheel.

In quartz stopwatches, the “second hand” is located in the 6 o’clock position. Here, the fourth wheel is geared to rotate once per minute and the second hand is directly attached to the wheels’ arbour.

The fourth wheel also drives the “escape wheel”, which are alternately attached on two opposite arrows called “pallets”. The pallet is located within the pallet lever which automatically operates back and forth. The lever’s end part has a “fork” which triggers the “impulse pins” on the balance wheel’s shaft. Every time the balance wheel swings towards its center position, the automatic stop watch’s lever unlocks – releasing one tooth of the wheel.