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Silicium escapement wheel
From Wikipedia, the free encyclopedia
The accuracy of a mechanical movement is dependent on the accuracy of the timing device. The timing device for a mechanical Heart Beat Calibre is the balance wheel, the balance-spring and the escapement. The balance wheel spins back and forward with a frequency of 4Hz. The period of swing of the balance wheel determines the accuracy. The crucial element in escapement design is to give just enough energy to the balance wheel in order to keep it swinging, and to interfere with the free swinging of the balance wheel as little as is possible. As the lubrication of the escapement ages, friction will increase, and less power will be transferred to the balance wheel.
The escapement must keep the balance-spring winding and unwinding. For most of watch-making history, these requirements have involved considerable friction in the escapement. The teeth of the escapement wheel are powered by the main spring power source, and they actually slide against the ratchet teeth before they lock; this is the friction which kicks the anchor but which requires lubrication. In a modern escapement, the teeth of the ratchet are made of very hard and very polished stone, but lubrication is still essential. The ticking sound of a watch is the sound of the balance-spring gear and escapement teeth locking into with each other. If the lubrication fails (through age-related thinning or drying) then the escapement can suffer damage and metal parts will require replacement. The increased reliability of modern watches is due primarily to the higher quality oils used to lubricate the escapement. Typically, a mechanical calibre needs to be cleaned and re-oiled every four years.
A major improvement is an escapement that does not require regular lubrication. The silicium escapement wheel was first introduced to the industry by Patek Philippe & Co in 2005. [1] Silicium is the ideal material for use in watch making as it is not magnetic, is extremely hard (1100 Vickers compared to 700 Vickers for steel), and is highly resistant to corrosion. The biggest advantage of a silicium escapement wheel is that it does not need to be lubricated. As it does not need to be lubricated, previously mentioned disadvantages such as age-related thinning and drying of lubrication will no longer occur [2].
- ^ Reinventing the Wheel (English). Retrieved on February 22, 2007.
- ^ Unlocking the Silicium Code (English). Retrieved on March 16, 2007.