You wear a watch every day, but have if you were asked “how do automatic watches work?” would you know? Well, that’s what we are here to answer today. Let’s get to it.
What Is An Automatic Watch?
An automatic watch winds itself automatically. Another word for automatic is mechanical. So another way to put it is it winds mechanically.
Now, when we say a watch winds itself automatically, this does not mean it does so in a literal sense of the word. An automatic watch simply gets its energy from the wearer’s movements.
When Did The Automatic Mechanical Movement Start?
The question of who invented the automatic watch movement is disputed even till today. Some people say it was Hubert Sarton in the year 1778. Others say it was Abraham-Louis Perrelet in 1777. Notwithstanding, the automatic winding can be traced back to several centuries ago.
The automatic watch movement was incorporated for the first time into a watch by a French inventor named Pierre Joseph de Rivaz. This happened in the 18th century. Much later, the movement was again perfected by a man named John Harwood in the early part of the 20th century.
It was Harwood who was from Bolton near Manchester in England who developed the first watch with automatic winding. His system used a weight that swung back and forth through a 130-degree angle in tune with the movement of the wearer’s wrist.
Rolex watch manufacturers improved Harwood’s system for the famous Oyster Perpetual. They achieved this by mounting a semicircular weight in the center of the movement where it would rotate through a 360-degree angle.
Rolex also increased the amount of energy stored in the mainspring in order to provide 35 hours of reserve power. Modern automatic mechanical watches have a power reserve which ranges from 30 hours to a one month period.
Please note that every movement has a different power reserve.
Even though the first automatic watch appeared on the scene as early as the 18th century, they stayed a niche item until they became popular in the 20th century. This new method of wearing a wristwatch took it from the safety of a pocket to the constant movement of being worn on a wrist. Finally, the time had arrived for the automatic watch movement to have its leap forward.
Before we go into how an automatic watch works, let’s look at the components of an automatic watch. This way, you won’t get lost when we start mentioning watch parts when explaining the mechanism.
Components Which Enable The Automatic Watch Movement
The rotor is a weight that is shaped like a semi-circle and is mounted on the movement. It is also referred to as the oscillating weight.
The rotor swings through a 360-degree angle because of the movements of the watch while it’s worn on the wrist. A series of gears enable the movement of the rotor which winds the mainsprings supplying the watch with mechanical energy.
2. Reverser Mechanism
This mechanism is placed in between the gears and the rotor. It allows the rotor to wind the mainspring in whichever direction it needs to turn.
There are many reverser mechanisms with the best known being the pawl winding system. It comprises two wheels each which comprise a bottom and a top disc.
The discs are connected by a spring less sprawl which unclicks one wheel and then the other wheel depending on the rotation direction.
The crown is a wheel or a button located on the outside of the watch case. When it’s pushed in, the crown can be turned in order to manually wind the mainspring. When the crown is pulled out, it can be turned in order to set the hands of the watch.
This is a coiled metal strip that stores energy when it’s wound up. It gradually releases this energy as it unwinds. The energy is then transferred via the movement of the gears.
5. Gear Train
The gear train is a series of gears that transfer energy from the mainspring to the escape wheel.
This is the part of the wristwatch which divides the time into equal fractions. At consistent intervals, the escape wheel releases the energy which is supplied by the gears to the lever.
Synthetic ruby pallets placed on the lever help to reduce any friction between the lever and the escape wheel as they come into contact with each other. The ticking sound you’re probably familiar with is actually the sound of these pallets striking the teeth of the escape wheel.
This kind of escapement is known as a Swiss level escapement and it is widely used even today.
In recent years, many improvements have been made to the escapement often building on the qualities of modern materials e.g. silicon.
7. Balance Wheel
This is the regulating component of a wristwatch and is often known as the heart of the movement. This is because it beats between 5 and 10 times a second.
The balance spring is assembled with the balance wheel. Every time the balance wheel swings in a particular direction, the in and out movement of the balance spring brings it back to its center position.
These are synthetic and hard stones made up of aluminum oxide and corundum. The jewels are fixed at high friction points such as the center of a wheel which is constantly rotating. This is to reduce the wear and rubbing caused by the movement.
In the early watch movements, the jewels which were used were real rubies. Today as a result of the expensive price of rubies and new processes, watch movements use synthetic jewels.
These artificial jewels actually don’t have any color but they are tinted red in order to make them more attractive. They are also tinted red to serve as a reminder of the original precious stone.
How Do Automatic Watches Work?
There are 6 stages required in order for an automatic watch to count time and drive the hands which displays the hours, minutes and seconds on the dial. These are explained below:
Step 1: Wrist Movement Turns The Rotor
When you wear an automatic watch and swing your arms, this motion causes the rotor in the watch to turn. The rotor then winds the mainspring but it does this through some gears also found in the watch.
But notice something. Automatic watches still come with a crown, right? Well, this is because automatic watches, though self-winding, can also be wound manually using the crown.
Step 2: Gears Move The Energy To The Escapement
The gears we talked about in the first step that winds the mainspring, they generated energy from all that turning and transfer the energy to the escapement.
Step 3: Escapement Provides Energy To Balance The Wheel
From step 3, the escapement now moves this energy to the balance wheel at regular intervals.
Step 4: Balance Wheel Oscillates
Now, in an automatic watch is a lever which comes with pallets. These pallets then begin to push the balance wheel first one way, and then the other way. By doing this, the balance wheel oscillates using the energy generated by the mainspring in step 1 and provided in bits by the escapement.
Step 5: Gear Train Drives The Watch’s Hands
Now, as the balance wheel swings, each swing causes the geartrain to advance by a specific amount. On a watch, the hands are mounted on the gears. So, the movement of the geartrain, in turn, causes the hands to move.
Step 6: The Watch’s Hands Turn On The Dial
Finally, you see the hands turn on the dial.
Should You Wind Your Automatic Watch Manually?
Not every automatic watch has the option to be manually wound so it all boils down to the watch movement. If your automatic watch should ever stop ticking, you may need to shake it a little to kick start the gears into motion again.
However, a lot of modern watch movements allow you to wind your wristwatch by hand. This is a useful option to have especially if you don’t move your watch frequently or you don’t wear it very often.
If you’re not sure if you should wind your automatic watch manually by hand regularly, there’s no need to worry because it will depend on the movement of the watch.
Your watch manufacturer would have provided this information if you’re not sure. Generally speaking, the less you depend on winding your automatic watch by hand manually, the slower the components will wear out.