Shulou(Shulou.com)11/24 Report--

If there is no battery in the period, how can the mechanical watch keep time accurately? (above) We introduced the clockwork that provides power in the mechanical watch, the gear that slows down the speed of the winding box, the escapement that controls the rotational speed, and the pendulum wheel group that provides accurate travel time frequency. (medium) period does not have the battery, how can the mechanical watch run time accurately? (middle) We introduced the splint for fixing the parts, the pawl to prevent the clockwork from being reversed, the gear and the day-counting function to drive the rotation of the second hand to the minute hand. But it also leaves a big question-how to wind up and set the date and time without opening the watch case? In this issue, we start with turning the handle to solve this problem.

First of all, let's take a look at the crown (the head of the handle) and the rod attached to it. This crown is the main interface for operating mechanical watches.

The crown is installed on the outside of the case and is in direct contact with the user. The handle has a square section, which is equipped with two parts-the vertical wheel and the clutch wheel:

The vertical wheel has a circular hole, so it can rotate easily on the handle. The square hole of the clutch wheel fits the square structure of the handle, which makes it can only rotate with the crown:

Let's put these parts together. I temporarily hid the date ring to prevent it from blocking our view:

Notice that on the back of the watch, the vertical wheel engages with the crown gear. In order to be able to turn the vertical wheel, we have to let the clutch wheel push it tightly-I marked this thrust with a blue arrow in the picture below. The shapes of the adjacent faces of the vertical wheel and the clutch wheel fit, and if we turn the crown now, they will lock each other. Finally, we can turn the crown gear by turning the crown clockwise and drive the rest of the winding mechanism.

If we rotate the crown counterclockwise, the vertical wheel and crown gear will be stuck by the pawl and the clutch wheel will be pushed away along the shape of the adjacent face. This safety mechanism ensures that even if the crown is twisted in the wrong direction, the movement will not be damaged.

It seems that we have achieved the goal of winding up by turning the crown. But there is a small problem to be solved-we need an external force that can push the clutch wheel toward the vertical wheel.

And, at some point, we want to achieve other goals by turning the crown. In addition to winding up, we should also be able to adjust the date and time independently. We will switch these three functions by pushing the crown to different positions. Let's build such a switching device. First, install the calibration rod and the setting rod:

Now, if we pull the crown out or push in, the two rods will rotate around their fulcrum and drive each other in an extremely complex way:

A positive view of the push-pull crown if it is shown with other parts, it will be difficult to see how they work, so let's hide the irrelevant parts. Notice how the two rods lock each other when pushing and pulling the crown:

From the back perspective, a groove in the push-pull watch crown handle locks the small rod on the setting rod, so that the push-pull crown can drive the setting rod. The other rod above it also pushes and hooks the calibrator so that the crown drives the calibrator together.

At present, this mechanism has not worked well, so we have to add the setting wheel to the small pole above the calibration rod:

The setting wheel can rotate freely on the pole. If we pull out the crown now, we can see that the setting wheel will engage the upper needle dividing wheel:

By turning the setting wheel, we can set the time of the mechanical watch, but in order to turn the wheel, we have to slide the clutch wheel so that it pushes the setting wheel so that the rotation of the crown is transmitted to the setting wheel through the clutch wheel:

This presents a challenge-we need to change the position of the clutch wheel according to different working modes so that it engages the vertical wheel when winding up, and meshes the setting wheel when setting the time. This is about to bring out the clutch lever:

In the close-up below, you can see that the clutch rod just fits the groove on the clutch wheel, so when the clutch rod rotates around its fulcrum, it will give the clutch wheel a push inward or outward to make it slide. As for how the clutch lever is driven, it is because setting the lever will push it when we pull the crown.

We are about to finish this small turnstile mechanism, but there are only three small details left. First of all, we have to secure these parts-there is nothing yet to prevent them from falling off from their carefully arranged position. Second, when the crown is pulled out, there is no special clasp to fix it-we may unconsciously push it to change the mode of operation when we rotate the crown. Finally, when we fully push the crown in to switch back to the winding mode, we want the clutch rod to reliably return to its original position. This requires the setting of a positioning lever, which can achieve these three goals:

The positioning rod is locked to the main splint by screws to prevent other parts from falling off. Its various "arms" and "legs" can also hold down the parts. Let's take a look at how setting the positioning rod solves the other two problems, and notice the three small grooves I pointed out with the gray arrow:

When we push and pull the crown, the small rod on the setting rod will buckle into one of the three grooves. In order to jump to a different groove, the rod must bend the long arm of the positioning rod, which creates the tension to push the rod into the nearest groove. In the end, we have three positions that balance the forces on all the parts-once locked, we don't have to worry about accidentally switching the working mode when turning the crown.

Finally, with regard to the setting of the positioning rod, there is a small part of it tightened on the clutch rod at the other end, and I pointed out its position with a gray arrow:

When the clutch rod rotates, the shrapnel of the metal can easily turn the clutch rod back. When the crown is in date or time mode, the setting rod will prevent the clutch rod from bouncing back, but once we return to the upper winding mode, the shrapnel of the positioning rod will turn the clutch rod back, thus sliding the clutch wheel back.

In fact, there is an amazing design, but it is hidden from a flat point of view. If you have a good memory and do not have a battery in the middle, how can a mechanical watch keep an accurate time? (middle) at the beginning of the chapter on pawls, we put a small lever on the main splint before installing the splint on the winding box, and then continue to talk about how to use pawls to prevent the winding from being reversed.

The considerate editor knows that most of you have forgotten, so put the picture again on the short end of this small lever to fit the groove of the clutch wheel, and when we pull out the crown and drive the clutch wheel, the small lever will turn:

When the lever turns to the bottom, it will rub against the pendulum wheel, making it impossible to move-which will stop the watch. As a result, when we pull the crown to the bottom and enter the time setting mode, the stop lever will hinder the swing of the pendulum wheel and stop the watch. In English, there is a word "hacking" to describe this action. Therefore, when we set the time, the second hand will not rotate itself at the same time, which helps to improve the accuracy of the calibration time.

Let's put all the parts together and see again how the whole shank mechanism works. When the crown is completely pushed, its rotation will drive the clutch wheel, then the vertical wheel, then the crown gear, then the ratchet and wind up:

When the crown is fully pulled out, its rotation drives the clutch wheel, setting the wheel, the dividing wheel, the clockwheel, and the tube hidden inside the clockwheel. (review, the wheel tube allows us to set the time without being stuck by pawls that prevent the winding from being reversed.)

Finally, when the crown is pushed to the middle, we enter the date setting mode. But in order to achieve this goal, we still need to add an additional sun wheel, let's put it in a small groove in the main splint:

Note that the sun wheel can slide up and down the grooves. If we pull the crown to the middle and turn it, we can turn the sun wheel, and it can hook the teeth inside the date ring. The date locator spring ensures that we can lock the date ring in a valid position:

Personally, I think this whole rotating mechanism is a mechanical miracle. These complex and collaborative components are arranged in an extremely organized manner, and each part can assume multiple roles. The old pocket watch is wound with a single button, and its crown is only used to set the time, but now it represents getting rid of the winding button, so the whole mechanism is also called keyless mechanism (keyless works). With only a few carefully designed parts and a crown, we can control the different setting functions of the table. Before moving on to the next chapter, let's install the minute hand and fasten the splint to protect the remaining parts:

We are nearing the completion of the watch movement. The last part to be installed allows the watch to wind up automatically while we are walking.

Automatic winding mechanism when a person wears a watch to move his arm, the spatial orientation of the watch will constantly change on this day. Even when walking, the watch swings slightly relative to the ground. Generally speaking, all the energy used to move the watch is wasted, but the automatic winding mechanism will try to capture some of the energy to tighten the main winding.

To understand how it works, we have to attach the whole automatic winding mechanism to the watch. Its main part is a counterweight that can rotate freely around the center. When the counterweight rotates, it drives a series of gears, and the last gear engages with the ratchet, thus tightening the winding in the winding box:

It is very important that the counterweight can rotate freely. In the following picture, I will rotate the space orientation of the watch, and gravity will always drag the counterweight below, which makes the counterweight rotate relative to the rest of the watch:

Recalling the winding mechanism we discussed in the medium term, you may remember that the ratchet can only turn in one direction, because the pawl is intended to prevent the main winding from reversing spontaneously. However, the counterweight can swing back and forth, which usually means that any gear transmission connected to it will also rotate in both directions.

However, if you look back at the automatic winding mechanism, you will find something special-turning the counterweight back and forth, the output gear will only rotate in one direction. I put a little black spot on the gear so you can see more clearly:

To understand what happened, let's first look at all the parts involved in this mechanism:

When the counterweight rotates, the green gear attached to the bottom of the counterweight drives two blue gears. Most of this part is similar to the splint-fixed gear set we have seen before. However, as you may have guessed, the secret of this one-way transmission lies in the double combination of yellow and blue gears. Let's see how they combine:

The blue gear can rotate freely on the yellow gear, while the fish rod can rotate around the hole in the blue gear. Notice that there is a special shape inside the yellow gear. In the following picture, I removed the center of the blue gear so that you can see what's going on inside.

When you turn the blue gear counterclockwise, the fish rod just slips through the inside of the yellow gear. And when you turn the blue gear clockwise, one of the fish rods will jam the yellow gear and drive it. This wonderful mechanism transfers the power of the blue gear to the yellow gear in one way.

The self-winding mechanism has two such gears-one drives the output wheel when it rotates clockwise and the other drives the output wheel when it rotates counterclockwise. In the image below, you can see what happens when you turn the gear attached to the counterweight. In order for you to see more clearly, I removed the irrelevant parts:

Notice my highlighted pair of yellow and blue gears, which are the ones that really receive power directly from the counterweight gear and pass it on to the output gear. Only one pair of such gears is "activated" at the same time-the other pair is either idling or acting as an intermediary to change the direction of rotation to ensure that the output gear is always wound in the right direction.

Relative to the gear attached to the counterweight, the output gear rotates very slowly, so it takes a lot of arm swing to wind it up completely. However, at the time of the day, the automatic winding mechanism usually ensures that the wind-up has enough energy.

The true size of the mechanical watch in all the illustrations so far, we have magnified the parts many times for easy observation, but in the last picture below, you will eventually find that all the parts are actually very small.

The rounded rectangle around the mechanical watch represents the size of a credit card-if you have one at hand, you can compare it on the screen. I hope this will make you realize how small the true size of the parts we have introduced is.

Conclusion in the 1970s, mechanical watches began to be replaced by quartz watches. The quartz watch is timed by the electron count of vibrating quartz crystals. With the development of technology, the watches worn by Volkswagen rely more and more on digital circuits. The modern smartwatch bears some resemblance to the original watch only in appearance and position.

Mechanical watches are not as accurate as electronic watches. They are more vulnerable and need regular maintenance. Despite these defects, these equipment show us the subtlety of mechanical engineering. By skillfully using miniature gears, levers and springs and combining them organically, a mechanical watch has changed from a cold part to a living life.

Author: Ciechanowski

Translation: herding sheep

Revision: depth

This article comes from the official account of Wechat: Institute of Physics, Chinese Academy of Sciences (ID:cas-iop), author: Ciechanowski

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