Constant force escapement and jumping seconds mechanism in watches

Abstract

This invention relates to a constant-force escapement and jumping seconds mechanism for a watch, belonging to the field of mechanical watch technology. The mechanism is integrated onto a constant-force seconds wheel and includes a constant-force seconds wheel gear shaft (1), a constant-force seconds wheel plate (2), and a constant-force spring (5) connecting the two. A locking mechanism consisting of an S-shaped planetary gear support (6), an end-face gear (7), a planetary gear shaft (8), a constant-force escapement wheel (9), and a locking stone (10) periodically controls the constant-force seconds wheel gear shaft (1) to perform a fixed-angle stepping motion, enabling the seconds hand mounted on the constant-force seconds wheel gear shaft (1) to achieve a jumping seconds function. Simultaneously, the constant-force seconds wheel gear shaft (1) ensures that the constant-force spring (5) maintains a constant elastic potential energy within a one-second cycle. Driven by the constant-force spring (5), the constant-force seconds wheel plate (2) outputs energy to the escapement system with a constant torque. Through the above mechanism, this invention effectively solves the problem of timekeeping accuracy caused by the decay of the mainspring torque and simultaneously realizes the jumping seconds display function.

Description

Technical Field

[0001] This invention relates to a constant force escapement and jumping seconds mechanism for watches. Background Technology

[0002] In traditional watchmaking, power is transmitted from the mainspring barrel through a gear train to the escapement system, which then transmits it to the balance wheel and hairspring system. This power output is not uniform. When the mainspring is fully wound, the torque is strong, and the balance wheel and hairspring receive a lot of energy. As the mainspring is about to unwind, the torque is weak, and the balance wheel and hairspring receive less energy. The balance wheel and hairspring will have a higher amplitude when receiving strong torque than when receiving weak torque. Theoretically, the period of the balance wheel and hairspring's oscillation is independent of the amplitude, but in reality, different amplitudes directly affect the period of the balance wheel and hairspring system. This error is called isochronism error in watches. The decay of the mainspring torque is the primary cause of isochronism error.

[0003] In 15th-century Europe, watchmakers invented the fusée-and-chain transmission system to solve this problem. This system, through a clever set of conical pulleys and a chain mechanism, achieved automatic power compensation and is one of the earliest "constant force" or "equal torque" devices in the history of mechanical engineering. The device consists of a load-balancing tow wheel, a chain, and a barrel. The load-balancing tow wheel is pagoda-shaped, with continuous spirals of varying radii on its surface. The two ends of the chain are wound around the barrel and the load-balancing tow wheel, respectively. When the mainspring is fully wound, the chain connects to the part of the tow wheel with the smallest radius; when it is nearly empty, it connects to the part with the largest radius. This achieves a constant torque on the mainspring through the lever principle (torque = force × lever arm). However, due to the height of the tow wheel and the difficulty of manufacturing the chain, it is no longer practical in modern watchmaking.

[0004] In a watch, the seconds wheel shaft and the seconds wheel plate are rigidly connected (by riveting), and the entire assembly of the seconds wheel shaft and the seconds wheel plate is usually referred to as the seconds wheel. In a watch movement, the seconds wheel follows the balance wheel and hairspring, moving once per beat (half a cycle in a lever escapement) or one cycle (one cycle in an impact chronometer escapement), depending on the escapement mechanism. The second hand is usually directly mounted on the seconds wheel shaft, so its movement is the same as the seconds wheel, moving once every half cycle or one cycle. This type of second hand display is called a sweeping second hand. For example, in a watch using a lever escapement with a frequency of 18000 vib / h (2.5 Hz), the escapement wheel moves once every half cycle, so the second hand appears to move once every 0.2 seconds, or 5 times per second. Summary of the Invention

[0005] This invention addresses the impact of mainspring torque variations on watch accuracy. The constant-force escapement of this invention solves the problem of mainspring torque decay affecting the oscillation period of the balance wheel and hairspring system. This invention uses a constant-force escapement system on the seconds wheel to divide the mainspring torque into several parts, which are then evenly transmitted to the watch's escapement system, which in turn transmits the energy to the balance wheel and hairspring system. This ensures that the torque received by the balance wheel and hairspring system is the same every second. The constant-force escapement operates for one second, perfectly achieving the jumping seconds function in the watch's display system (i.e., the second hand moves once per second). Furthermore, this invention significantly improves upon traditional sesame-and-chain mechanisms in terms of space requirements and manufacturing difficulty. The present invention discloses a constant force escapement and jumping seconds mechanism for a wristwatch, comprising: a constant force seconds wheel assembly, which is composed of a constant force seconds wheel gear shaft (1) and a constant force seconds wheel plate (2), wherein the constant force seconds wheel gear shaft (1) and the constant force seconds wheel plate (2) are flexibly connected; a constant force spring (5), the inner end of which is fixed to a constant force spring inner post (3) rigidly connected to the constant force seconds wheel gear shaft (1), and the outer end of which is fixed to a constant force spring outer post (4) rigidly connected to the constant force seconds wheel plate (2); a planetary gear system, comprising an S-shaped planetary gear support (6) rigidly connected to the constant force seconds wheel gear shaft (1), a fixed end face gear (7), and two planetary gear shafts (8) symmetrically installed at both ends of the S-shaped planetary gear support (6); and two constant force escapement wheels (9), which are respectively rigidly connected to the two The planetary gear shaft (8) and two locking stones (10) are rigidly connected to the constant force second wheel (2). The planetary gear system and the locking stones (10) form a locking mechanism, which controls the movement of the constant force second wheel shaft (1) by periodically engaging and disengaging the constant force escape wheel (9) with the locking stones (10). The constant force second wheel shaft (1) receives power from the mainspring barrel and stores energy by winding the constant force spring (5). The constant force second wheel (2) outputs energy to the escapement system under the drive of the constant force spring (5). Thus, in each working cycle, the energy output by the constant force second wheel (2) to the escapement system remains consistent, and the constant force second wheel shaft (1) performs a fixed-angle stepping motion to achieve the second hand jumping. The constant force second wheel (2) has a fan-shaped window for the constant force escape wheel (9) to pass freely through. The invention also includes a limiting pin (11), which is rigidly connected to the constant force second wheel (2) to limit the extreme position of the S-shaped planetary gear support (6) when the mainspring energy is depleted. When the teeth of the constant force escape wheel (9) are locked by the lock stone (10), the direction of its force is perpendicular to the locking surface of the lock stone (10). A second hand is mounted on the constant force second wheel gear shaft (1), and its action of being released and rotating by a fixed angle each time directly drives the second hand to achieve the display function of one tick per second. Attached Figure Description

[0006] AppendixFigure 1 The front view of the S-shaped planetary gear bracket (6) close to the limiting pin (11).

[0007] Appendix Figure 2 The back view of the S-shaped planetary gear bracket (6) close to the limiting pin (11).

[0008] Appendix Figure 3 The image shows the front view of the constant force escape wheel (9) locked to the lock stone (10).

[0009] Appendix Figure 4 The image shows the constant force escape wheel (9) locked to the back of the lock stone (10).

[0010] Appendix Figure 5 This is a side view of the constant force escape wheel (9) locked to the lock stone (10).

[0011] Appendix Figure 6 This is a schematic diagram of the planetary gear system and the lock stone (10).

[0012] Explanation of labeling.

[0013] (1): Constant force second wheel gear shaft; (2): Constant force second wheel plate; (3): Constant force spring inner stake; (4): Constant force spring outer stake; (5): Constant force spring; (6): S-shaped planetary gear bracket; (7): End face gear; (8): Planetary gear gear shaft; (9): Constant force escape wheel; (10): Locking stone; (11): Limiting pin. Detailed Implementation

[0014] The present invention provides the following solution to the above-mentioned problems.

[0015] The constant force escapement of this invention is integrated into a constant force seconds wheel (see appendix). Figure 5 On the ), this constant force second wheel is composed of the following components.

[0016] Constant force seconds wheel gear shaft (1). This gear shaft meshes with the watch's three-wheel plate, receives torque from the barrel, and the seconds hand is also mounted on this gear shaft.

[0017] Constant force second wheel (2). The constant force second wheel (2) rotates once per minute. The constant force second wheel (2) meshes with the escape wheel gear shaft and is flexibly connected to the constant force second wheel gear shaft (1). The constant force second wheel (2) has a fan-shaped window to allow the constant force escape wheel (9) to pass freely. The constant force second wheel (2) is driven by a constant force spring (5).

[0018] The constant force spring inner stud (3) is rigidly connected to the constant force second wheel gear shaft (1). The mainspring transmits torque to the constant force second wheel gear shaft (1) through the gear train. The constant force second wheel gear shaft (1) winds the constant force spring (5) through this rigidly connected constant force spring inner stud (3) in a period of 1 second, so that the constant force spring (5) maintains a constant elastic potential energy.

[0019] The constant force spring outer pile (4) is rigidly connected to the constant force second wheel plate (2).

[0020] A constant force spring (5). One end of the constant force spring (5) is fixed to the inner post (3) of the constant force spring, and the other end is fixed to the outer post (4) of the constant force spring. During installation, the constant force spring (5) will have a certain preload. The constant force spring (5) has elastic potential energy after being coiled by the constant force second wheel gear shaft (1). The constant force spring (5) can store the torque transmitted from the constant force second wheel gear shaft (1) through the mainspring, and then transmit it to the escape wheel through the constant force second wheel plate (2).

[0021] S-shaped planetary gear support (6). The S-shaped planetary gear support (6) is rigidly connected to the constant force second gear shaft (1), and planetary gear shafts (8) are installed at both ends of the S-shaped planetary gear support (6). The S-shaped planetary gear support (6) rotates once per minute.

[0022] The end face gear (7) is in a fixed state and cannot move freely. It meshes with the teeth on the planetary gear shaft (8).

[0023] Planetary gear shafts (8). Planetary gear shafts (8) are mounted at both ends of an S-shaped bracket. The planetary gear shafts (8) revolve around the constant force second gear shaft (1) for a period of 1 minute. Planetary gear shafts (8) mesh with end face gears (7). There are two planetary gear shafts (8), and they have the same structure and function.

[0024] A constant force escapement wheel (9). The constant force escapement wheel (9) is rigidly connected to the planetary gear shaft (8). There are two constant force escapement wheels (9), and they have the same structure and function.

[0025] Lockstone (10). Lockstone (10) is rigidly connected to the constant force second wheel (2) and moves in the same manner as the constant force second wheel (2). Lockstone (10) is made of synthetic ruby ​​to reduce friction. There are two lockstones (10), and they have the same structure and function.

[0026] Limit pin (11). The limit pin is rigidly connected to the constant force second wheel (2). When the bar is empty, it is used to limit the position of the S-shaped planetary gear carrier (6) so as to prevent the constant force escape wheel (9) from touching the edge of the fan-shaped area of ​​the constant force second wheel (2).

[0027] The following explains how the present invention achieves constant transmission of spring torque.

[0028] Because the constant force spring (5) has a preload during installation, the S-shaped planetary gear bracket (6) is close to the limit pin (11) when the bar is empty (see Appendix). Figure 1 When the watch is unwound, the user replenishes the mainspring by rotating the crown. The mainspring transmits its torque to the constant force second wheel gear shaft (1) through the gear train. The constant force second wheel gear shaft (1) has a certain free movement angle in the counterclockwise direction (see Appendix). Figure 1 The constant force second wheel gear shaft (1) coils the constant force spring (5) counterclockwise through the rigidly connected constant force spring inner stake (3), giving the constant force spring (5) elastic potential energy. At the same time, the constant force second wheel gear shaft (1) drives the S-shaped planetary gear support (6) to rotate counterclockwise, and the planetary gear shaft (8) rolls counterclockwise on the end face gear (7). Finally, the teeth of the constant force escape wheel (9) will fall onto the lock stone (10) (see appendix). Figure 3 With appendix Figure 4 At this time, the free motion of the constant force second wheel gear shaft (1) is restricted by the lock stone (10). When the constant force escape wheel (9) is locked, the force is perpendicular to the lock stone (10) to avoid any component force other than vertical force acting on the constant force second wheel plate (2) when locking.

[0029] When the constant force second wheel gear shaft (1) is locked, the constant force spring (5) has already replenished the potential energy required for the normal operation of the balance wheel and hairspring. The elastic potential energy of the constant force spring (5) is smaller than the torque of the mainspring on the constant force second wheel gear shaft (1), so the elastic potential energy of the constant force spring (5) cannot be released to the gear train on one side of the mainspring system. However, the elastic potential energy of the constant force spring (5) can be released through the outer stud to the constant force second wheel plate (2) which is flexibly connected to the constant force second wheel gear shaft (1). The constant force second wheel plate (2) then transmits the elastic potential energy of the constant force spring (5) to the escape wheel.

[0030] When the constant force second wheel (2) drives the balance wheel and hairspring system with a lever escape frequency of 2.5Hz, the constant force second wheel (2) will move 1.2 degrees counterclockwise in 0.2 seconds. When 1 second has passed, and the constant force second wheel (2) has moved 5 times (the constant force second wheel rotates 6 degrees), the constant force escape wheel (9) teeth disengage from the lock stone (10).

[0031] After the constant force escape wheel (9) disengages from the lock stone (10), the entire constant force second wheel gear shaft (1) is in a free state, and can rotate freely at an angle of 6 degrees. The elastic potential energy released by the constant force spring (5) in 1 second will be immediately replenished. When the constant force second wheel gear shaft (1) rotates freely counterclockwise by 6 degrees, it will drive the S-shaped planetary gear support (6) to rotate by 6 degrees. At this time, the planetary gear shaft (8) will drive the constant force escape wheel (9) to rotate counterclockwise, and then the constant force escape wheel (9) will be locked again by the lock stone (10). When the constant force second wheel gear shaft (1) rotates freely counterclockwise by 6 degrees, the second hand will also skip 6 degrees, which is exactly the angle that the second hand needs to rotate in one second. At the same time, the function of skipping seconds is realized.

[0032] When the torque of the watch mainspring drops to a point where it can no longer drive the constant force spring (5) to coil (i.e., after the watch mainspring is exhausted), the S-shaped planetary gear support (6) will come into contact with the limit pin (11), and the watch will stop and wait for the next winding.

[0033] Throughout the entire process, the mainspring never directly drives the balance wheel and hairspring system. Instead, the constant force escapement mechanism of this invention divides the energy into several equal portions to drive the balance wheel and hairspring system. This improves the impact of changes in the mainspring torque on the watch's timekeeping accuracy.

Claims

1. A constant force escapement and jumping seconds mechanism for a wristwatch, characterized in that, include: A constant force second wheel assembly, which consists of a constant force second wheel gear shaft (1) and a constant force second wheel plate (2), wherein the constant force second wheel gear shaft (1) and the constant force second wheel plate (2) are flexibly connected; A constant force spring (5) has its inner end fixed to the inner post (3) of the constant force spring that is rigidly connected to the constant force second wheel gear shaft (1), and its outer end fixed to the outer post (4) of the constant force spring that is rigidly connected to the constant force second wheel plate (2). A planetary gear system includes an S-shaped planetary gear carrier (6) rigidly connected to the constant force second gear shaft (1), a fixed end face gear (7), and two planetary gear shafts (8) symmetrically installed at both ends of the S-shaped planetary gear carrier (6). Two constant force escapement wheels (9) are rigidly connected to the two planetary gear shafts (8); and two lockstones (10) are rigidly connected to the constant force second wheel (2); The planetary gear train and the lock stone (10) constitute a locking mechanism. The locking mechanism controls the movement of the constant force second wheel gear shaft (1) by periodically engaging and disengaging the constant force escape wheel (9) with the lock stone (10). The constant force second wheel gear shaft (1) receives power from the mainspring barrel and stores energy by winding the constant force spring (5). The constant force second wheel plate (2) outputs energy to the escapement system under the drive of the constant force spring (5). Thus, in each working cycle, the energy output by the constant force second wheel plate (2) to the escapement system remains consistent. At the same time, the constant force second wheel gear shaft (1) performs a stepping motion at a fixed angle to achieve the second hand jumping.

2. The constant force escapement and jumping seconds mechanism for a wristwatch according to claim 1, characterized in that, The constant force escape wheel (2) has a fan-shaped window so that the constant force escape wheel (9) can pass freely through it.

3. The constant force escapement and jumping seconds mechanism for a wristwatch according to claim 1, characterized in that, It also includes a limiting pin (11), which is rigidly connected to the constant force second wheel (2) to limit the extreme position of the S-shaped planetary gear support (6) when the spring energy is depleted.

4. The constant force escapement and jumping seconds mechanism for a wristwatch according to claim 1, characterized in that, When the teeth of the constant force escape wheel (9) are locked by the lock stone (10), the direction of its force is perpendicular to the locking surface of the lock stone (10).

5. The constant force escapement and jumping seconds mechanism for a wristwatch according to claim 1, characterized in that, The constant force second wheel gear shaft (1) is equipped with a second hand. Each time it is released and rotates at a fixed angle, it directly drives the second hand to achieve the display function of one tick per second.

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