Escapement and watches. These are described individually below. Although the invention of the crystal oscillator and the quartz clock in the 1920s shifted technological research in timekeeping to electronic methods, major advances in the design of mechanical escapement are still happening. Coaxial escapement, invented by English watchmaker George Daniels around 1974 and patented in 1980 has rather dramatically increased the accuracy and durability of mechanical watches. Yoshikazu Akahane with teams of engineers at Seiko Epson developed the spring drive movement around 1977, and obtained not less than 230 patents between 1982 and the present. The reliability of an escapement depends on
Mechanical energy of conservation of mechanical energy states that if a body or system is subjected only to conservative forces, the mechanical energy of that body or system remains constant. The difference between a conservative and a non-conservative force is that when a conservative force moves an object from one point to another, the work done by the conservative force is independent of the path. On the contrary, when a non-conservative force acts upon an object, the work done by the non-conservative force is dependent of the path. According to the principle of conservation of mechanical energy, the mechanical energy of an