How many stones are there in a military watch? Gems of Time

Hour stones

Stones is a term used to refer to watch parts made from precious stones, synthetic or, less commonly, natural. A good quality mechanical wristwatch has 15-17 jewels: two pallets, one pulse on the pulse balance roller, two each - bearings and supports on the balance axis, anchor, second and intermediate wheels, etc. More expensive watches have a larger number of jewels . The use of pallets, impulse stones, trunnion supports and axles made of artificial ruby ​​reduces energy loss 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 that serve as radial or axial supports; stones that help transmit force or movement; multiple jewels (such as 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 that cover stone holes, but are not an axial support; stones that support watch parts (for example, drum, transmission 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 points //-VII. The number of stones to a certain extent determines the quality of the watch. Wristwatches without additional devices have 15-17 jewels, with additional devices 21-23 jewels, and in some complex designs up to 29 jewels. The number of stones in the wristwatch K-2609 (see Fig. 129) is 19. The use of ruby ​​stones in watches is due to the fact that when transmitting very small moments to the running wheel, and then to the balance, friction losses in the transmitting pairs should be minimal ; for example, on the axis of the drum of the same wristwatch, when the spring is fully wound, the moment is 8.56 N-mm, and the moment on the axis of the running wheel at i = 3600 is only 0.002 N-mm, i.e. the overall efficiency of the transmitting pairs is = 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 0.08 in some cases. In table 24 shows the types of stones normalized by GOST "7137-73.

The type of stones STs, STsBM and SN are used for the axle journals of the central wheel and subsequent axles, including the axis of the anchor fork; type of stones SS, NP and N - 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 a double balance roller. STs2M type stones are used in the supports of the central tribe.

In high-precision and 1st class watches, four balance stones are used in the anchor fork assembly. Stones are made with working surface roughness of 11-13 classes and a dimensional tolerance of 0.005-0.01 mm. The overall dimensions of the stones are very small. Ruby has high hardness, but also increased fragility. Diamond tools are used to process it. In table 25 shows the clearance values ​​of the mating parts.

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

The stones are used to make pallets, impulse stones, as well as supports for the journals of the tribes and axles.

Watch stones can retain lubricant for a long time, ensuring stable operation of the watch mechanism. The watch mechanism uses stones of various shapes and sizes: applied, through, pallets, pulsed (ellipses).

Overlay stones are used as thrust bearings to reduce friction in supports. They are placed on both sides of the balance axis. Sometimes overhead stones are also used as thrust bearings for the axles of an anchor fork, anchor tube, etc. Through stones of various shapes are used as bearings for the journals of axles and tubes. The journals of the tribes and axles of the wheel system and the travel mechanism, as a rule, have a supporting shoulder, so there is a cylindrical polished hole for them in the through stones.

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

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

The pallets of the anchor fork are also made from artificial ruby. The pallets have the shape of a rectangular prism. According to the angle formed by the impulse plane and the base plane, they are divided into input pallets with a more obtuse angle and output 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 cross-section in the form of a cut ellipse. In a watch, it interacts the balance with the anchor fork.

In watches with a conventional kinematic scheme, as a rule, from 15 to 17 stones are used. Changing the kinematic scheme and introducing various additional devices in watches increases the number of stones; in some designs it reaches 29 or more.

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

Regardless of the brand of mechanical watch, be it an expensive “Oris” or an ordinary “Poljot”, any wristwatch contains watch stones.

In turn, the number of stones in a watch mechanism is one of the main criteria that speaks about the quality of a 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 stones located inside the watch, and not in the external decorative inlay, the British call watch stones “jevels” - precious stones. So, what is the connection between the quality of a watch mechanism and the number of stones it contains, what is their function and why are they considered precious?

Precious stones in watches are not used to decorate the product, as, for example, they decorate Parker fountain pens and ballpoint pens. Any master watchmaker, without hesitation, will answer that stones in watches are needed to reduce the coefficient of friction between parts, which helps to increase the wear resistance of the entire watch mechanism. This is precisely the wording 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 watches with rubies in the mechanism were made by the famous English watchmaker - George Graham (1673-1751) - at the beginning of the 18th century, he was the first to realize that by reducing the coefficient of friction, high quality could be achieved. By the way, it was he who came up with the idea of ​​a free anchor escapement mechanism, which is still used in watches throughout his life. watchmaker produced more than 3,000 pocket watches, which embodied the most advanced ideas of the watchmaking craft of that time. In all his watches, starting from 1725, the axles, impulse rollers and pallets were made only from ruby.

However, it cannot be said that today watch stones are used exclusively to reduce friction in the watch mechanism. 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 feasibility of using precious stones as bearings for watch mechanisms?

The fact is that the diameter of the axle trunnions of pocket and wrist watches is very small (about 100 microns). From the school physics course it is known that the force of pressure has a direct dependence 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 supports. Plus, the stone is not subject to corrosion, and its polished surface retains its properties much longer than metal.

Today, artificial ruby ​​is an ideal material for making watch stones. This is justified by the fact that this material has high wear resistance, great hardness, can be easily processed, which is very important, it can be polished with very high quality. Artificial ruby ​​also has an excellent wettability coefficient, which allows it to hold watch oil on the surfaces without loss, ensuring minimal wear of rubbing surfaces and uninterrupted operation of the entire watch mechanism. In addition, over time, artificial ruby ​​not only does not oxidize the lubricant, but does not even cause the slightest change in its properties.

Depending on the purpose of watch stones, several types are distinguished: applied, pallet, impulsive and through.

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

The shape of the pallet stone 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 impulse plane and the base plane. The exit pallets have a sharper angle than the entry pallets.

To transfer the interaction from the balance to the anchor fork, impulse stones are used. In cross-section, they represent 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 axle of the tribe and the axles of the wheel system. Through stones with a spherical hole are used for balance axle journals. The 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 most consumers choose watches based on the number of stones, use watch stones in the mechanism inappropriately (for example, placing them around the automatic winding rotor, etc.) just to write an impressive number on the dial. No matter how prestigious the manufacturer's brand, be it Rado or Orient, the number of jewels in a watch must correspond to the number of axles.

TECHNICAL REASONS

The important parts of a mechanical watch are mainly those that move, that is, the gears, balance and regulator. In earlier times, the pivot points of these parts rotated directly into holes drilled into two thick brass sheets separated by posts. To make assembly and repair easier, the top plate was later replaced with individual elements called "panels".

The lower copper plate (called the "base plate") was drilled with small holes into which the ends of the rotating rods rested. These holes also contained small oil spouts that allowed oil to flow into the holes to lubricate the friction points of the turns. Over time, they had to be cleaned, because... the resulting combination of oil and dust formed an abrasive substance that acted like sandpaper, slowly filing away the softer base of the plate and to some extent even the harder steel rods. With prolonged use, the abrasive action of the oil dust mixture, working in concert with the turning action of the centers, made the holes oval. In this case, the clock would start to run erratically and eventually stop.

These observations led watchmakers to look for a material that was stronger and would resist more wear from the centers. The material they settled on was ruby, second only to diamond in hardness.

A LITTLE HISTORY

The use of ruby ​​takes us back to 18th century England (the cradle of qualitative timekeeping), where watchmakers first had the idea of ​​using small ruby ​​balls to support centers of balance. The technique of processing ruby ​​was invented by a Swiss optician and astronomer, Nicholas Fatio, who sailed to England in the hope of implementing his invention. He tried to obtain a "royal privilege" for his technique, but Fatio did not receive it and as a result, other skilled workers began producing rubies for watches.

In those days, these stones were second-rate, not popular in the jewelry trade. The technique of precision processing of rubies gave the British watchmaking industry excellence for some 20 years. After this, French watchmakers such as Abraham-Louis Breguet brought the techniques of the English masters to France. This was the beginning of the end of the British monopoly.

For many years, this relatively expensive, labor-intensive technique limited production exclusively to very high-quality and expensive watches. Slowly, the making of these watches became more industrialized, and their parts more accessible to other aspects of watchmaking.

Creation of Synthetic Rubies:

top picture - creating elongated pear-shaped parts of an artificial crystal.

bottom picture - The pear-shaped pieces are cut using a diamond cutting tool. The slices are then cut in half, into squares and circles measuring 0.3 to 0.5 mm in thickness and 1.15 to 2.55 mm in diameter.

SYNTHETIC RUBIES

A further decrease in price accompanied the creation of synthetic rubies based on a method developed in 1902 by Auguste Verneuil, a professor at the Paris Conservatoire of Arts and Crafts. In fact, synthetic rubies, just like their natural counterparts, are corundum, that is, transparent aluminum oxide.

In the industrial counterfeiting process, the main constituent alumina (aluminum oxide) is subjected to a series of operations, that is, refining, heating, alloying and crystallization, which results in pear-shaped pieces of artificial ruby. Chromium oxide is added to produce the red color of natural rubies.

Large-scale ruby ​​production allowed the creation of large quantities of synthetic stones that were more uniform in quality than those found in nature. The jewelry trade takes the majority of these stones. In watch making, the cost of rubies came mainly from labor (training needed) as the cost of raw materials was relatively low. Having said this, it must be noted that approximately 90% of the ruby ​​is destroyed and only the remaining 10% is usable for watches.

COMMERCIAL TRICK?

In the public's mind, the idea that a watch contains jewelry gives it a certain added prestige value. Manufacturers were quick to exploit this belief and began adding unnecessary stones to increase the price of their products. The term "upjeweling" was an American term coined to refer to this dubious practice, which was quite common in the US at the time. Until it was canceled by US Customs authorities, who rejected "upjeweled" imports from entering the country. There are some people who suggest that their real motives may have been less noble and that it was simply a kind of camouflage protectionism for the American watch industry.

Today, Swiss watchmakers no longer use this dubious practice, and their advertising is not based on the number of jewels in the movement. The total number of rubies, i.e. "gem decoration", may change. In simple manual mechanical watches, the number of jewels varies from a minimum of 14 to a maximum of 19. In automatic or more complex watches, the number of rubies is higher. One day, someone started a rumor that a repairman had stolen rubies from a watch and replaced them with copper parts. This is a completely unfounded myth. For a watchmaker to remove rubies and replace them would require a lot of effort and would certainly not be worth his time, given that artificial rubies cost a few cents.

To sum it all up, the presence of ruby ​​stones in a watch is of course a factor that adds to the quality of the watch. They are essential for the long-term and correct functioning of a good quality watch.

material taken from the site http://www.europastar.com/

Stones in a watch mechanism are used to stabilize friction and increase the service life of contacting elements.

The source of energy in any watch mechanism is a spring, which in appearance resembles a flat steel band. When the watch is wound, it curls and absorbs energy. The second end of the spring band is attached to the drum, which transmits energy to gears that create a wheel system that provides energy transfer. The speed of rotation of the gears is controlled by the presence of a trigger mechanism, consisting of many moving elements mounted on the axles.

Any mechanism that includes rotating axes needs to minimize the friction of the moving elements against the base. The less friction there is, the longer the watch can run without winding and the longer the parts will last. Any other mechanism could use bearings, but watches use the same stones. They are not afraid of wear and corrosion, and the polished surface of the stone remains perfectly smooth and clean for a long time. In addition, watch stones extend the life of the mechanism, since the friction of the stone on the metal does not affect the condition of the mechanism as much as the friction of two metal elements.

The impulse stone, which is installed on the pendulum and constantly strikes the horn of the anchor fork, deserves special attention. The impulse stone must be particularly wear-resistant.

What stones are used in the watch mechanism?

Only manufacturers of premium products use natural diamonds and rubies in their watches, and then usually only in limited editions or in models made to order. Mostly the stones in watches are artificial sapphires and rubies. Some watch manufacturers, such as Seiko, even have separate divisions that specialize only in preparing watch stones. By the way, artificial stones cope even better with their tasks, since they have a more uniform structure and do not contain impurities.

Number of jewels in watch

It’s worth clarifying right away that if one watch has 17 stones and another 40, this does not mean that the second is 2 times better than the first. In a watch with self-winding and three hands, a maximum of 25 jewels can be installed; it will not be possible to install more, even with a great desire. A larger number of stones are used only in watches with chronographs and other complex movements. However, some manufacturers, trying to attract the attention of the buyer, deliberately install stones in places where they are not needed.

Modern manufacturers of mechanical watches use stones for four purposes:

• Through (accept radial loads in axial supports).
• Overhead (reduce friction at the ends of the axles).
• Impulsive (transmit energy to balance).
• Pallets (ensure normal operation of the anchor fork).

The basis of any wristwatch is through stones, of which there must be at least twelve. Each through stone has a small recess intended for watch oil. The generally accepted standard indicates that a watch must have at least 17 jewels, although in recent years there has been a clear trend towards the use of 21 jewels, which has a positive effect on the wear resistance of movements.

Swiss watch mechanism- this is the holy of holies of mechanical watches, where entry to the uninitiated is strictly prohibited. There are many myths associated with the use of stones in watch calibers. For example, it was previously believed that the number of stones affected the quality of the ride. Is this really so and why these stones are called precious - we will try to clarify in today’s article. The main question lying on the surface remains the role of stones in mechanisms. After all, there is not a single marking without indicating the number of stones inside the caliber.

Every watchmaker will answer without hesitation that stones in watches are needed to stabilize friction and reduce the degree of wear of the contacting surfaces of the mechanism. The NIHS 94-10 standard on the function of stones in movements was adopted in Switzerland in 1965.

Clock mechanism and mineral bearings

The watch mechanism is designed in such a way that its main axes are constantly under load: the mainspring forces them to rotate, and the spiral regulator restrains this rotation. The balance support bears the most work: in addition to the reciprocating movements, a rather weighty balance is attached to it. The junction of the axis with the platinum - the stationary part of the mechanism - is subject to strong friction, and to stabilize it in Swiss watch design special bearings are used.

It is known that the coefficient of friction of hardened steel and ruby ​​is exactly the same as when paired with steel and brass. Why do watchmakers use precious minerals in the mechanisms of Swiss watches? The axle journals that fit into the bearing are very small in diameter, measuring only one hundred microns. Therefore, watch stones are needed rather to increase the durability of the axle supports in the mechanism, where reducing friction is a natural solution to the problem. The advantages of stone over metal are obvious: it does not oxidize or corrode, and a polished stone surface will retain its shape longer. The stones cope better with the load from impacts on the horns of the anchor fork and with the pressure of the protrusions of the anchor wheel.

George Graham, the founder of the Graham watch manufactory, was the first to use precious stones in a watch mechanism. In 1713, Graham invented the free anchor escapement, which is still used today. Graham is responsible for the creation of more than three thousand pocket watches, all of which contain ruby ​​bearings. Since 1725 it was possible in caliber.

Rubies in watches and their optimal quantity

Rubies in watches located inside the mechanism depending on the functions. In the usual three-hander, the optimal number of ruby ​​stones reaches seventeen. Sometimes the design approach makes it necessary to replace some of the stones with brass bearings, and in this case the true number of stones is written in the characteristics of the watch. Each additional complication adds a number of jewels to the movement.

There are many curious cases when the number of stones is several times greater than the required number. For example, markings that include fifty, eighty, or even one hundred stones cause confusion among the buyer. Much does not mean good. This move is misleading for beginners. All stones that are actually used in the mechanism of a Swiss watch are called functional. All other stones on the caliber perform a decorative function, which do not fit into the standard markings accepted throughout the world.

Where are stones not needed? In quartz watches. The only moment of load on the wheel train occurs during the rotation of the stepper motor. Due to the virtual absence of mechanical movement in quartz watches, wear is almost completely prevented. Therefore, if the characteristics of a quartz watch indicate the number of one, two stones or without stones, this does not mean anything terrible. Those manufactories that are of very high quality without a single stone.

Mechanical Swiss watches for two centuries were made with real ruby ​​stones inside the mechanisms. The situation changed when in 1902 the technology for growing artificial rubies was invented. This turn of history largely made it possible to produce watches en masse. Nowadays, natural minerals are used very rarely, because artificial stones are more reliable and easier to process than natural ones. Of course, the realization that the watch caliber contains natural rubies brings great aesthetic pleasure. But the use of synthetic stones does not diminish the value of real watch masterpieces.