How does a mechanical alarm clock work

How does a mechanical watch actually work?

What goes on in the mechanical clockwork

Regardless of whether you are a lover or collector or even the master himself - a look into a mechanical clockwork is always fascinating. What actually happens there and how does the clock know what time it is?

The assemblies of a mechanical watch: winding, drive, gear train, escapement, balance and hand train

A mechanical clockwork consists of several assemblies. Firstly, this includes - the Elevator: Energy is supplied to the clockwork via it, without which it would otherwise not run at all. An adjusting device connected to the elevator is also used to set the time. In the case of the wristwatch, both are carried out via the well-known crown.
Second - the drive: He is responsible for providing the mechanical energy supplied by the elevator to operate the clockwork. In a wristwatch, this is a spring in a barrel.

Third - the movement or gear train: It is a gear that transfers the energy between the drive and the escapement. The escapement - fourth - in turn slows down the movement. As its name suggests, it "inhibits" the uncontrolled and unrestrained flow of the movement and converts the rotational energy transmitted from the barrel via the movement into a periodic cycle. Fifthly, this periodic cycle is regulated by the Balance: So it is responsible for how exactly the clockwork works, i.e. how the clock works.

Sixth - that Handwork: It translates the movement of the movement into the movement of the hands and thus ensures that the time is correctly displayed on the dial.

Where does the power required in a mechanical clockwork come from?

If you turn the crown of a mechanical wristwatch, the barrel is moved via a winding shaft, the winding wheels, and a ratchet wheel. A shaft, called a spring core, rotates in it and tensions the mainspring. This then provides the energy for the clockwork. The aforementioned ratchet wheel, together with a spring and a pawl, the so-called ratchet, ensures that the energy in the barrel is stored.

On the other hand, the spring transfers the energy stored in it to the gear train via the externally toothed barrel. In its basic version, the gear train consists of three wheels - the Minute wheel, one Third wheel and the Second wheel.

When the gear train is running, the speed of rotation of the wheels increases from the barrel gearing to the seconds wheel, while the force (torque) decreases.

How is power transmitted in the clockwork?

The gear train - also known as the movement - is an assembly that is present in every mechanical clockwork. It is responsible for the transmission of the power from the energy storage device - in a wristwatch that is the barrel - to the regulator - in the wristwatch the escapement with the swinging balance wheel. The movement is made up of several gear stages, each of which consists of a gear - usually a spur gear with more than 20 teeth - and a drive - usually with fewer than 20 teeth. Two gears are almost never in direct contact with one another; instead, one gear engages in a drive. This construction is stable, since the drives are milled from one piece together with the shaft, and saves space, since the individual gears can be arranged spatially one above the other instead of just linearly behind one another. The meshing conditions must be calculated based on the frequency of the balance-wheel spiral system, and the number of teeth of the individual wheels must be selected so that each wheel has the desired rotational frequency, since the gear train is also transformed into the pointer train, i.e. to display the time.

The movement consists of a minute wheel, third wheel and second wheel with their respective drives. But it actually starts with the gearing on the barrel, which engages in the minute wheel drive. Hence the term "drive" for the gear "driven" by the cogwheel. The shaft of the first wheel in the drive protrudes far beyond the movement, namely up to the dial, and here bears the minute hand. The minute wheel meshes with the pinion of the third wheel. This gear stage - arranged between the minute and seconds wheel - has no display function, but is used to transmit power, change speed and change direction. There is a "fast" translation. The speed from the minute to the second wheel increases, the torque decreases. Since the following second wheel, like the minute wheel, must turn clockwise, the third wheel also serves as a directional rectifier. The third wheel engages in the drive of the third wheel in the gear train, the fourth wheel. This rotates once a minute and defines the second, regardless of whether a second hand is on its shaft or not. If a second hand is attached directly to the shaft of the second wheel, one speaks of a direct second (small second). To display the second from the center of the movement (central second), another translation is required, usually via the third wheel. The seconds display is then no longer in the direct power flow of the gear train and one speaks of the indirect second. The fourth wheel engages in the drive of the escape wheel. The escape wheel gear has a certain special position. His instinct is still part of the work. The wheel with its special toothing, its step-by-step movement and its interaction with the anchor is already part of the escapement.

What does the escapement do in the mechanical movement?

The gear train is followed by the parts of the inhibition With Escape wheel and anchor. Some people still consider the escape wheel to be part of the gear train, but it has a certain special position because, through its step-by-step movement, it "inhibits" the gear train in the uncontrolled process and is therefore to be regarded as part of the inhibition. The escapement ensures that the gear train runs at exactly the same speed as the time with seconds, minutes and hours must be displayed on the dial, i.e. an hour is exactly an hour and not just 50 minutes. And this now happens as follows:
At the end of the gear train, the fourth wheel drives the escape wheel, which is blocked by an anchor. Ultimately, however, the pressure from the gear train becomes so great that a tooth of the escape wheel pushes past the anchor. The armature receives an impulse which it passes on to the balance wheel. This impulse sets the balance wheel in motion. At the same moment the anchor, which can move back and forth like a seesaw, blocks the escape wheel again. The balance, for its part, swings out, but then becomes hers spiral braked and withdrawn. When it is back at zero, it moves the armature again. This releases the escape wheel and at the same time sends the next impulse to the balance wheel. This now swings out in the opposite direction. The "game" starts all over again. Balance and inhibition are also called Oscillation system of the clockwork and are responsible for ensuring that the wheelwork runs at a precisely defined speed. But we still don't know what time it is.

The time is displayed in the clockwork from the gear train

For the display of the time that is Handwork responsible. Let's go back to the minute wheel: it is part of the wheel train, but its shaft extends to the dial, where the minute hand, just like the wheel in the clockwork, turns around itself exactly once an hour, thus indicating the minute. But that is not enough to display the exact time. Therefore, the minute wheel engages in a change wheel, which reduces the number of revolutions to one twelfth and thus to that of the hour wheel. On the hour wheel sits the pointer of the same name, which usually circles the dial twice a day or once every twelve hours. The second hand is sometimes driven directly by the second wheel of the movement. Because of the step movement of the escape wheel, it also rotates in the same way. His small steps are a symbol of a mechanical watch. Only the pointer mechanism makes the work of the clockwork visible on the dial and the clock thus becomes a time measuring device. It is located directly under the dial and is set from the outside, namely via the crown.

When the crown is pulled into the pointer position, a clutch separates the flow of power between the gear train and the pointer train and enables the hands to be adjusted without damage. Often, based on the pointer mechanism or the minute wheel, additional wheels or entire gear chains are driven for additional functions, such as a 24-hour display, a date or even an entire calendar including the moon phase, striking mechanisms or alarm clock. The functional expansion of the watch involves so-called complications, if several of them are found in a watch, one speaks of a major complication. MaRi

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