• Uncategorized

    Board Layout Of Mechanical Watches

    The overall skeleton of the mechanical watch movement is the layout of the splint and the circuit. The history of mechanical watches has gone through hundreds of years. Whether it is pocket watches or later pocket watches, and today’s popular watches, there is no particularly large difference in the level of movement design. The difference is that the overall size of the movement is gradually reduced, and the required performance of the movement is also gradually improved. What is more critical is that with the rapid development of science and technology, numerical control technology has made the manufacture of movement parts from difficult to easy. So many more mechanical functions that were not possible before can now be implemented. Then it is the splint that I want to talk about for the complex movement function, and the layout of the classic splint in the movement also reflects the skills of the watchmaking masters.
    Classification of board layout
        The circuit layout of the movement is also very particular. At present, there is a relatively simple idea to classify, which is to divide the movement according to the position of the two wheels that mesh with the barrel wheels in the original drive train. The basic transmission forms are center two-wheel type (two wheels in the center of the movement) and partial two-wheel type (two wheels off the center of the movement). These two types of transmission can be further subdivided according to the actual needs of the movement design, and both have their own advantages and disadvantages. As far as the center two-wheel type is concerned, its advantages are that the overall structure of the movement is compact, and the design and The processing difficulty is relatively simple; the disadvantage is that the space utilization ratio of the plane and the axial direction of the movement is relatively low; for the off-center two-wheel type, its advantages just make up for the former disadvantage, and the space utilization ratio of the movement plane and axial comparison High, which provides favorable conditions for improving the overall performance of the movement. The disadvantage is that the design and processing are more difficult.
    Classic board Lepine and Savonette
       These two movement-named circuit boards started with pocket watches. The main feature of the Lepine board layout is that the movement aligns the head, the small second hand with the center of the movement at three points, which is what we often call the 9 o’clock small second hand; and the main feature of the Savonette board layout is the movement The second hand is at a 90-degree right angle with the center of the movement at three o’clock, which is what we often refer to as the small 6 o’clock second hand. Today, the two classic board layouts are from the two movements ETA6497 and ETA6498. The positioning of the board layout is mainly from the initial positioning of the movement design. The so-called positioning is the way in which the seven parts mentioned above are laid out, which will directly determine the board layout of the plywood. Because the initial positioning of these two movements is a pocket watch movement, the overall size is relatively large, the maximum diameter of the movement reaches 37.2mm, in addition, the functions of these two movements are relatively single and belong to the most basic movement, based on this Design concept The core of the movement adopts the most two-wheeled tone. At the same time, the basic seven parts of the movement also have their own relative position relationship. Why do you say that? The answer is that this transmission form itself has determined that the two wheels that directly mesh with the motive box wheel are at the center of the movement.

       Then the first determination of the initial design is the position of the prime mover. This part determines that the winding system is also determined, but the two belong to a close relationship. The winding wheel of the winding system will be directly connected to it. The upper ratchet of the prime mover meshes. Then the difference between these two movements is that the position of the small second hand is determined, so the transmission gear train needs to be arranged according to the position of the second wheel. The second wheel is at the center and the second wheel is at 9 o’clock or 6 o’clock. Position, in order to add a three-wheel between the second wheel and the second wheel to achieve the transmission ratio and the direction of gear rotation. At the same time, the other side of the second wheel is connected with the escapement and the vibration system. This completes the main drive chain. Already formed. This transmission method is also called a direct-pass movement, which is more popular in the design of tourbillon movements. We can see that whether it is the Lepine board circuit at the 9 o’clock second wheel or the Savonette board circuit at the 6 o’clock second wheel, the support of the main drive chain is fixed through three plywood (the main drive chain’s The lower support is located on the base plate of the movement). These three plywoods can be called bar splints (support of the original drive train and the upper bar system) and upper splints (support of the drive gear train) according to the different parts of the main transmission chain of the movement. ) And pendulum splint (support of the vibration system), in fact, there is a splint hidden under them called a fork splint (support of the escapement), this splint is specifically for the key component of the escapement-the escapement fork Set.
    ETA 2892 movement board
       This movement is recognized by major brands as a movement that can be mounted on high-end mechanical watches. Its main feature is that the overall size of the movement is small and relatively thin. ETA2892 circuit layout According to its movement diagram, we can see that it belongs to a typical two-wheeled type, more precisely a three-wheeled output type. The so-called three-wheeled output means three-wheeled and displayed The ETA6497 and ETA6498 we talked about are direct transmission, which means that the box wheel is directly connected to the display system. This movement is set at the center of the big three hands, so the second wheel must be positioned at the center of the movement. That is to say, the three wheels are connected to both the display system and the second wheel. The side is also the escapement and balance spring system, so the complete main drive chain is connected. The plywood used in each part of the main drive chain of this movement is exactly the same as the three plywoods mentioned earlier, and the fork plywood cannot be ignored. A domestic-made movement also uses a three-wheel output transmission chain, but because the positions of the prime mover and the speed control system are based on the overall needs of the movement, the layout of the transmission gear train between them is also required. After some consideration, the shape of the splint and the arrangement of the support holes also need to be more determined.

    ETA2892 movement chart

    Domestic movement chart
    German table three quarters road
       The board circuit structure of the movement is mainly determined by the transmission form according to the design needs. The three plus one splint structure is also the most commonly used splint layout mode, but some well-known brands are unique in order to highlight the brand’s unique design in the movement. The basic idea of ​​rearranging the circuit board of the movement is to disassemble or integrate it, or even to disrupt it. We may have seen that the assembly surface of the movement has been set with many splints, and each component of the transmission chain has been A piece is set and then fixed by screws; there is the well-known German three-quarter plywood board layout, which has formed the symbol of a German local brand. Its board design philosophy is exactly the same as the one we mentioned earlier. The splint and the upper splint generally exist independently due to the peculiarities of the fork splint and the swing splint.

    Langer three-quarter splint movement

    Langer three-quarter splint movement
    Author’s comment: Behind the mechanical watch is always the most important place for many watch fans. Historically, the layout of the splint road behind many classic mechanical watch works can be the finishing touch for master watchmakers. As far as the major well-known brands are concerned, behind each watch, the distinctive characteristics of the brand itself will be revealed, so that every fan who has experienced it will never forget it. That reveals a pleasing plywood road, accompanied by high-quality finishing and polished handicraft.