Why stones are needed in watches. What are "stones" and why are they needed in hours

watch stones

Stones is a term used to refer to watch parts made from precious stones, either synthetic or, more rarely, natural. Wrist mechanical watch good quality have 15-17 jewels: two pallet ones, one - impulse on the impulse balance roller, two each - bearings and supports on the balance axis, anchor, seconds and intermediate wheels, etc. More expensive watches have more stones. The use of pallets, impulse stones, trunnion supports and artificial ruby ​​axles reduces energy losses due to friction and wear of parts.

Watch stones are divided into two groups according to their purpose:

• 1. Functional - if they serve to stabilize friction or reduce the wear rate of contacting surfaces of parts. Functional stones include:

stones with holes serving as radial or axial supports; stones that contribute to the transmission of power or movement; several jewels (e.g. ball clutches for a winding mechanism) combined into one functional jewel, regardless of the number of jewels.

• 2. Non-functional - decorative stones. These include: stones covering stone holes, but not being an axial support; stones that serve as a support for watch parts (for example, a drum, gear wheel, etc.)

When marking, only the number of functional stones or functional stone supports is indicated. Watch stones are made from artificial ruby.

Ruby stones serve as supports (bearings) for the rotating axes of //-VII points. The number of stones to a certain extent determines the quality of the watch. Wristwatches without additional devices have 15-17 stones, with additional devices 21-23 stones, and in some complex designs up to 29 stones. The number of stones in the wrist watch K-2609 (see Fig. 129) is 19. The use of ruby ​​stones in watches is due to the fact that when transferring very small moments to the running wheel, and then to the balance, friction losses in the transmission pairs should be minimal ; for example, on the axis of the drum of the same wrist watch when the spring is fully loaded, the moment is 8.56 N-mm, and the moment on the axis of the road wheel at i = 3600 is only 0.002 N-mm, i.e. the overall coefficient useful action transmission pairs tbshch = 0.84 or one gear pair r\ = 0.96.

Of all minerals and metals, ruby ​​has the lowest coefficient of friction (paired with steel), equal to 0.12-0.15. During operation, this coefficient becomes even smaller, reaching in some cases 0.08. In table. 24 shows the types of stones normalized by GOST "7137-73.

The type of stones STs, STsBM and SN is used for trunnions of the axis of the central wheel and subsequent axles, including the axis of the anchor fork; type of stones SS, NP and H - for the balance unit, anchor and running wheel; type of stones P and PV - pallets of entry and exit of the anchor fork and type of stones I - impulse stone of double balance roller. Stones of the STs2M type are used in the supports of the central tribe.

In watches of increased accuracy and 1st class, four balance stones are used in the anchor fork assembly. The stones are made with the roughness of the working surfaces of the 11th-13th grade and the tolerance for dimensions of 0.005-0.01 mm. The dimensions of the stones are very small. Ruby has high hardness, but also increased brittleness. For its processing, a diamond tool is used. In table. 25 shows the gaps of the mating parts.

This material has high hardness and wear resistance, is well processed, can be polished. Artificial ruby ​​stones do not oxidize or decompose watch oil. In addition, this material has a beautiful appearance.

Stones are used to make pallets, impulse stones, as well as supports for pins of tribes and axles.

watch stones long time can retain grease, ensuring stable operation of the watch movement. Stones are used in clockwork various shapes and sizes: overhead, through, pallets, impulse (ellipses).

Laid on stones are used as thrust bearings to reduce friction in the supports. They are placed on both sides of the balance axis. Sometimes overhead stones are also used as thrust bearings for the axles of the anchor fork, anchor tribe, etc. Through stones of various shapes are used as bearings for the pins of axles and tribes. The trunnions of the pinions and axles of the wheel system and the travel mechanism, as a rule, have a support shoulder, therefore, in through stones they have a cylindrical polished hole.

The trunnions of the balance axis, which commits a large number of vibrations (432,000 vibrations per day), do not have a shoulder, therefore, in through stones, the hole for them is not cylindrical, but rounded, the so-called olivage (Fig. 22, d). ???

All through stones have a special recess, an oiler, in which watch oil is held. To prevent the stones from splitting, when pressing in through stones, a bullet-shaped lead-in chamfer is performed. The pressing force increases gradually.

Anchor fork pallets are also made from artificial ruby. Pallets have the shape of a rectangular prism. According to the angle formed by the momentum plane and the base plane, they are divided into entry pallets with a more obtuse angle and exit pallets with a less obtuse angle. The lead-in chamfer of the exit pallet is against the rest plane, and the lead-in chamfer of the entry pallet is on the rest plane.

An impulse stone (ellipse) is a cylindrical pin with a section in the form of a cut ellipse. In watches, it carries out the interaction of the balance with the anchor fork.

In watches with a conventional kinematic scheme, as a rule, from 15 to 17 jewels are used. The change in the kinematic scheme and the introduction of various additional devices in the watch increases the number of jewels, in some designs it reaches 29 or more.

Watch stones as a criterion for the quality of a watch mechanism

Regardless of brand mechanical watch, whether it's an expensive "Oris" or an ordinary "Flight", there are hour stones in any wrist watch.

In turn, the number of stones in the watch mechanism is one of the main criteria that speaks about the quality of the watch. The significance of this factor is also confirmed by the fact that information about the presence of stones is usually displayed on the watch dial. Moreover, although we are talking about about the stones that are inside the clock, and not in the outer decorative inlay, the British call watch stones "jevels" - gems. So, what is the connection between the quality work of a watch mechanism and the number of stones in it, what is their function and why are they considered precious?

Precious stones in watches are by no means used to decorate the product, as, for example, they adorn feather and ballpoint pens parker. Any master watchmaker, without hesitation, will answer that the stones in the watch are needed to reduce the coefficient of friction between the parts, which helps to increase the wear resistance of the entire watch mechanism. It is this wording that is indicated in the NIHS 94-10 standards, which were adopted in 1965 in Switzerland by the Normes de l "industrie Horloge Suisse organization. Although the first watch with rubies in the mechanism was made by the famous English watchmaker - George Graham (1673-1751) - as early as the beginning of the 18th century, he was the first to guess that by reducing the coefficient of friction, one could achieve High Quality. By the way, it was he who in 1713 came up with the idea of ​​a free escapement mechanism, which is still used in watches. Throughout his life, the watchmaking maestro has made more than 3,000 pocket watches, which embodied the most advanced ideas of watchmaking craft of that time. In all his watches from 1725 onward, axles, impulse rollers and pallets were made only from ruby.

However, it cannot be said that today, watch stones are used solely to reduce friction in the movement. After all, the coefficient of friction between hardened steel and a watch stone is approximately equal to the coefficient of friction between brass and steel. What is the expediency of using precious stones as bearings for watch movements?

The fact is that the diameter of the trunnions of the axes of pocket and wrist watches is very small (about 100 microns). It is known from the school physics course that the pressure force is directly dependent on the area of ​​the contacting surfaces. As a result, we can make a logical conclusion that watch stones are used not only to reduce friction, but also to preserve the axial bearings. Plus, the stone is not subject to corrosion, and its polished surface retains its properties much longer than metal.

To date artificial ruby- an ideal material for the manufacture of watch stones. This is justified by the fact that this material has high wear resistance, high hardness, excellent processing, which is very important, it can be polished very high quality. The artificial ruby ​​also has an excellent wettability coefficient, which makes it possible to keep watch oil on the planes without loss, ensuring minimal wear of rubbing surfaces and uninterrupted operation of the entire watch mechanism. In addition, the artificial ruby ​​not only does not oxidize the lubricant over time, but does not even cause the slightest change in its properties.

Depending on the purpose of watch stones, there are several types of them: overhead, pallets, impulsive and through.

The hemispherical surface of the overlay stones helps to reduce friction in the supports. As a rule, this type of stones is used as thrust bearings.

The shape of the stone "pallet" is a rectangular prism. This kind of watch stone is divided into input pallets and output pallets. Their purpose can be determined by the angle formed by the momentum plane and the base plane. Pallets have more than sharp corner than the input pallets.

To transfer the interaction from the balance to the anchor fork, impulse stones are used. In section, they are an incomplete ellipse, made in the form of a cylindrical pin.

Through stones come with cylindrical and spherical holes. A stone with a cylindrical hole is used as a bearing for the trunnion of the tribe and the axles of the wheel system. Through stones with a spherical hole are used for trunnions of balance axes. Main Feature of all through stones is the presence of an oiler - a special circular recess for holding watch oil.

In electronic-mechanical watches, depending on the complexity of the mechanism and the presence of additional devices (calendars, a separate stopwatch, etc.), 17 or more stones are used. However, some manufacturers, knowing that the majority of consumers choose watches by the number of stones, it is inappropriate to use watch stones in the mechanism (for example, they place them around the self-winding rotor, etc.) only to write an impressive number on the dial. No matter how prestigious the manufacturer's brand is, be it Rado or Orient, the number of jewels in a watch must match the number of axles.

Remember, back in childhood, we looked at father's or grandfather's wristwatches, on which the model, brand and number of stones were indicated. I have always been intrigued by the question - what are the stones in the watch for? And if they are also precious, then the watch itself became a family most valuable relic. We have grown up, but still this question can still excite. To understand this, you need to understand the work of the clock and what the notorious pebbles mean by themselves.

Stones in watches

"15 jewels" in the watch - what does it mean?

Let's figure it out first what are stones in a mechanical watch? So, watch stones are indispensable parts, sapphires or rubies are most often used, for durable work and less wear resistance of the product. These are bearings that stabilize the friction of parts in contact with each other. Usually 15-17 jewels are used per watch. Such a set is only in standard movements, expensive models have a much larger amount of jewelry in their composition.

In turn, they can be divided into:

1. Functional. These are the ones that are designed to work in the mechanism, provide durability and reduce friction between parts.
2. non-functional. Pebbles for decor. They have no connection with the axle supports, they can serve to hide stone holes.

On the dial, they usually write the first option, that is, the number of functional crystals.

How do mechanical watches work?

To understand this issue in more detail, you need to know how mechanical watches work. Any specialist knows what precious parts are for. Let's understand the issue in a simpler language.

The watch is powered by a special spring that looks like a flat steel band.

When you start the mechanism, the spring compresses and stores the energy that it transfers to the drum. The latter, rotating, passes it to the gears. Gears forming a special wheel system, rotate gradually, without wasting all the energy at once. How does this happen?

This problem is dealt with trigger mechanism. It completely controls the operation of the gears and prevents them from rotating randomly. At the head of this system is a balance regulator. Why is he needed? And in order for the wheel to rotate at a certain speed in one direction and the other.

Stones in clockwork

Functionality and work of stones

The stone in the watch is used instead of the bearing. The mechanism works on rotating parts that have their own axes. Each of them experiences tension from two sides, from balance regulator and from the spring. Everywhere there is a process of friction. To minimize it and reduce wear, bearings are needed. That's just their function and perform the stones.

What is the advantage of such unusual, but such necessary details?

Artificial or precious materials do not wear out or corrode

If they are properly sanded and processed, they will be smooth and clean all the time. They increase service life rotating parts. By the way, stones are not only used in watches. There are also impulse stones in pendulums.

Luxury in watches: jewels and their quantity

Now many are disappointed. natural ruby or diamond stones are very rare. Usually only limited and expensive production models are found with such a unique set. The most common is corundum, a crystalline mineral that has its own special structure of synthetic ruby ​​or sapphire.

mineral corundum

Such a mineral is also excellent affects wear resistance. Some stones are much better than natural ones. This means that synthetic material is better, more uniform and better due to the purity of the product.

How many jewels are in the watch? Many people are interested in this question. It is worth remembering that product quality does not depend on the number of stones.

For a good and durable watch, 15-20 stones are enough

It is simply pointless to put more than 25 stones in the mechanism. If the information from the manufacturer indicates the presence of 35 stones, for example, then this is no longer a simple three-hand mechanism.

Swiss models are very rubies are often used. The same question immediately arises - why do we need ruby ​​stones in mechanical watches and why are they good?

ruby stones

Mechanical Swiss Watches throughout its history, they were made only with rubies, moreover, natural ones. Everything changed only in 1902. It was at that moment that the technological explosion» - a method was created for growing artificial stones. There are mechanisms where they are not used. These are quartz products. It doesn't matter how many stones were used. It has its own system of work, which consists only in a single wheel gear. Only at that moment does the transfer of energy take place. IN quartz watch 1-2 can be involved ruby stone, but this does not mean that the integrity of the mechanism is violated. You can find out what time it is without them.

The use of crystals and precious materials in watch mechanisms has long been overgrown with myths and legends. But having understood this issue, you understand that there was nothing supernatural and complicated. Just need look deeper, to the very heart of the watch – to its mechanism.

15/04/2003

Stones are probably the most intriguing part of the watch mechanism. Why is their number always marked on the watch case or dial?

Stones are probably the most intriguing part of the watch mechanism. Why is their number always marked on the watch case or dial? Why do the British call them precious (jewels) and how much do they cost? What role do they play in the mechanism? Does their quantity affect the quality and cost of the watch itself? And these are just surface questions.

When asked why stones are needed in watches, any specialist will answer without hesitation: “To stabilize friction and reduce the degree of wear of the contact surfaces of the mechanism.” This is how the function of stones is indicated in the NIHS 94-10 standard, adopted in 1965 by the Swiss organization NIHS (Normes de l'industrie Horloge Suisse). Let's try to figure out what this means.

The stone sharpens the trunnion
If at least in general terms to imagine the work of the clockwork, it becomes clear that its main axes must be under constant voltage: on the one hand, the force of the mainspring presses on them, forcing them to rotate, and on the other hand, the speed of their rotation is restrained by the balance-spring regulator. The balance support experiences almost the greatest load throughout the mechanism. Not only does this axis perform reciprocating movements at high speed, but the balance itself is also fixed on it - a weighty thing.

The trunnions, with which the axles are in contact with the platinum and bridges of the mechanism, are made as thin as possible in order to reduce friction in the axle bearings and the energy consumption of the spring to overcome it. In any mechanism, a bearing is installed with a rotating axis and a fixed frame (platinum) to stabilize friction.

So, watch stones are usually used as bearings or thrust bearings for axle pins. In fact, it cannot be said that the stones are used to reduce friction in the axle bearings. And in principle, the coefficient of friction in a pair of hardened steel - ruby ​​​​(diamond) is approximately equal to the coefficient of friction of hardened steel paired with brass. Why then use jewels as bearings?

As mentioned above, wrist and pocket watch pins have a very small diameter - 100 microns. And it is known that the pressure force directly depends on the area of ​​the contacting surfaces. Thus, watch stones are designed not so much to reduce friction as to increase the durability of axle bearings in watches. In addition, the stones do not corrode, and by grinding the stone, you can get a perfect and long-term clean surface.

In addition to supports, stones are used in two more places that are subject to intense impact. Pallets are made from them, fastened on the shoulders of the anchor fork, and an impulse stone. Again - only a very strong mineral can withstand the pressure of the escape wheel teeth and impacts on the anchor fork horns.

It is not surprising that watch stones became a real godsend for watchmakers in the 18th century, when the era of pocket watches began. The mechanisms became so small that the parts under the pressure of the mainspring quickly became unusable.

The first watch with precious stones in the mechanism was produced in 1704. But the idea of ​​using them in such unusual quality belonged to the great English watchmaker George Graham (George Graham 1673-1751), who became famous for the invention in 1713 of the free anchor escapement mechanism, which is most common in our time. During his lifetime, Graham created over 3,000 pocket watches, and in all of them, since 1725, the axles, pallets and impulse roller are made of ruby.

Where are the stones
Since we figured out exactly what the stones are for, let's see what shape they should have, the types of stones and where exactly in the watch they serve.
Watch stones can be of the following types:
through
invoices
pallets
impulse

Through stones are the basis of watches. There are 12 of them in the classic 17-jewel movement. They perceive radial loads in the axle bearings. Some of them have cylindrical or olive (rounded) holes. All through stones have a special recess - an oiler that can hold watch oil.

Overhead stones are designed to reduce friction on the end surfaces of the axles. They are installed, as a rule, on the balance and axles of high-speed wheels. In quartz watches, thrust bearings are sometimes not placed at all.

The optimal number of stones in a simple mechanical watch with a side hand is 17. They are usually located as follows:

Balance support - 4 (2 through and 2 overhead)
Impulse stone (ellipse) - 1 Idle wheel axle - 2
Pallets - 2 Escape wheel axle - 2
Anchor fork axle - 2 Central pinion - 2
Axis of the second wheel - 2

Sometimes manufacturers, for design reasons, remove some of the stones: they put the stone only on the lower support of the central wheel, and press the brass bearing into the upper one, being guided by the fact that it has less pressure. In this case, it will honestly be written on the clock: 16 stones. Well, if the watch has a central second hand, there is no need for a second axis and the number of jewels is reduced to 15. Naturally, various additional devices and dials - calendar, stopwatch, automatic winding can increase the number of jewels.
IN Lately modern mechanisms use 21 stones: two pairs of stones are also placed at the ends of the axles of the anchor and third wheels, overhead stones are placed.

Industry versus nature
Until the beginning of the 20th century, real gems were found in pocket watches both inside the mechanism and, as a decoration, on the case. Everything changed when, in 1902, the technology of growing artificial sapphires and rubies was invented, which made it possible to increase the production of watch movements many times over. Watches have become a commodity. Now natural rubies are practically not used in watches. From a technical point of view, grown crystals are more stable in their properties and more predictable in processing. The only aspect by which real stones are still considered better than artificial ones is aesthetic.

A lot - not a little?
If in the previous section the typical species and the classical arrangement of stones were described, now let's see what deviations from the accepted norm are more common.

In principle, it is clear that the number of jewels in a watch depends on the number of axles. If, for example, a chronograph has additional dials with second hands, then it would be nice to protect the trunnions of their axes with stones, the same is the case with the repeater axis. However, when you come across such markings as “50 stones”, “83 stones” or even “100 stones”, bewilderment arises: how and why were they stuffed there ?!

In watchmaking, there is such a thing as “non-functional” or “decorative” stones - they can, for example, close an ugly hole in the circuit board or simply decorate the mechanism - if back cover transparent. But, according to the standard adopted throughout the world, only the number of functional stones is indicated on the marking. At least on all watches made after 1965. What is the point then?

The fact is that the concept of "functionality" is quite extensible. Someone thinks that the stones set for a smoother running of the calendar disk are not functional. But they really reduce friction, and much more. In conventional mechanisms, a force of 20-25 grams per millimeter is required to set the disc in motion. And the stones allow you to reduce this effort by half, which means significantly reduce the load on the mechanism. Isn't it functional, say, for ultra-thin or complex mechanical watches, which, in addition to the chronograph, also have moon phase indicators, power reserve and other functions?

True, there are quite funny examples. For example, the American company Waltham has released a watch on... 100 stones. 17 stones in them were in their rightful places, and the remaining 83 were placed around the circle of the self-winding rotor. At the same time, it turned out that 84 holes were drilled on the circumference, and one of them remained gaping with emptiness - the manufacturers did not want to exceed the round figure. The course of the rotor, hung with stones, was, of course, smoother, but this effect could be achieved due to fewer stones.

Or another example: a watch by a Swiss manufacturer, which, out of modesty, did not indicate its name, but proudly placed the marking “41 stones” on the lid. As you can see in the photo, 16 of these stones are inserted into the drum wheel, apparently to keep it from rubbing against the mainspring. Friction is, of course, reduced, but in a rather wasteful way. Although if people bought these watches just because of the number of stones indicated on the case, it is difficult to call them completely “non-functional”.

Another "extreme" is a watch without stones, because they are, in general, not needed in quartz movements. The wheel gear of the quartz mechanism is loaded only at the moment when the stepper motor turns. And in this case, since there is practically no tension in the axles, the only thing that is needed to reduce friction and prevent wear on parts is to make the surfaces as light as possible. Therefore, the boards and wheels of quartz watches are often made of plastic altogether.

And the coefficient of friction of steel axles on plastic or plastic on plastic is very low. Therefore, functionally in a quartz watch, stones are needed only in one place - the support of the rotor of a stepper motor. This is the only axle under tension. So the marking on a quartz watch “2 stones”, “1 stone” (if it is placed only under the lower trunnion) or even “0 stones” (No jewels) does not mean at all that you have been cheated of something. Happiness is not in stones.