9/7/2023 0 Comments Mechanical clockCalibrating the clock for a weekly winding also has the effect that the torque variation during the unwinding will be much greater than if it is done on daily basis, this would lead to a greater variation of the ticking rate (even though its weekly average is close to the specification). If the clock is calibrated so that it averages its specification when winding it up once a day, it will lag behind the actual time if it is wound up once a week. Ideally the clock should be calibrated so that the average ticking rate is closest to its specification. I evaluated the first 24 h past a full winding of the clock, but a better evaluation would require recording the clock as it completely unwinds for 8 days and a better reference clock.Īs explained before, the mainspring torque affects the ticking speed of the clock, so how one plans to wind up the clock is relevant when deciding how to calibrate it. My initial plan was to measure the accuracy of a mechanical clock so that I could calibrate it. The drifting waveform also contains a small amplitude oscillatory component that probably is associated to gears that rotate a few times per hour. This is likely caused by friction associated to gears that rotate once every 12 h. Assuming that the DAQ clock is accurate, a daily drift of ~8.7 s would be relatively good for a mechanical clock, but the performance would eventually continue to degrade as the mainspring continues to unwind (the clock can run up to 8 days when completely wound up).Īt every cycle, between 12:00 and 1:30, the clock tends to run slower than during the rest of the cycle. The mechanical clock drifted ~3.9 s and ~4.8 s from the DAQ clock on the first and second cycle respectively. As the mainspring unwinds, its torque diminishes, and this reduces the clock ticking even further. The generated plot revealed a few interesting aspects of the mechanical timepiece.Įxcept for very shorts periods of time, the mechanical clock tended to run slower than the reference DAQ clock. The next video shows briefly how every major component of a mechanical wristwatch works. Ticking rates typically go from 4 up to 8 ticks per second, and by measuring their rate it is possible to measure the accuracy of a timepiece and evaluate if it requires calibration. Mechanical timepieces generate a characteristic ticking sound when the escapement wheel is suddenly stopped by the pallet at each half-oscillation of the oscillator. The oscillator is the timekeeping element, and its purpose is to oscillate at a constant frequency, it can be either a balance wheel or a pendulum. The escapement wheel also transfers energy to the oscillator so that it stays oscillating while there is energy in the power source. The train wheel is connected to the escapement wheel, which is a mechanism that allows the wheel train to advance a fixed amount at each half-oscillation of the oscillator. The wheel train is made of multiple gears that through different gear ratios move the different hands of the timepiece. The power source can be a mainspring or a suspended weight, and its purpose is to store and deliver energy to the wheel train. The main components of a mechanical timepiece are: the power source, the wheel train, the escapement and the oscillator. In this post I will show how to use piezo-accelerometer sensor to measure the accuracy and analyze the vibration of a mechanical clock. The crisis drove mechanical watchmakers to focus on the higher end market to the point that mechanical watches became luxury goods, appreciated for their craftsmanship, precision engineering and aesthetic appeal. This caused a crisis in the Swiss watchmaking industry, and plunged the industry to the point that between 19 the number of Swiss watchmakers dropped from 1,600 to 600. The invention of the much simpler, inexpensive and more accurate quartz timepieces, mechanical timepieces began to fall into disuse. In the 14th century, the first mechanical clocks were invented and their accuracy continuously improved through multiple refinements such as the invention of the mainspring, the balance spring, and the pendulum. Ancient timekeeping devices included sun dials, candle clocks, water clocks and hourglasses. The history of timepieces dates back to ancient civilizations such as the Ancient Egypt, where obelisks were used to track the movement of the sun.
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