The escapement is the heart of a mechanical watch, the escapement wheel drives the escapement forks to escape and complete the action of locking, transmitting and releasing, and transmits the power to the balance wheel, which completes the distribution of the time to achieve the effect of regulating the speed. It can be said that the accuracy or otherwise of a mechanical watch has the greatest correlation with the escapement.
Historically, early escapements were invented by the British, with several types of escapements such as the T-wheel and the I-wheel. Then Breguet invented the lever escapement (both horse escapement), which, after some years of popularization and use, gradually replaced all other kinds of escapements and became a standard escapement used by all watchmakers.
The Co-Axial escapement was developed by Dr. George Daniels over a period of fifteen years. Coaxial escapement is a new type of escapement invented by Dr. George Daniels after fifteen years of research and development, and his starting point is to change the friction in the perpendicular direction between the escapement wheel and the escapement fork into the parallel direction, and the change of friction makes the traditional 3-5 years of maintenance and oil washing of mechanical watches extended to ten years. At the same time, because the basic conditions for the realization of the Co-Axial escapement are the screw-adjusted balance wheel and the non-calibrated hairspring, which makes the Co-Axial escapement movement can easily obtain the chronometer certification, so as to be able to keep time accurately. The Co-Axial escapement was a sensation in the world of watchmaking because it was the first time in more than 100 years that a new type of escapement had appeared in the world of watchmaking, with an almost perfect structure, which was very advanced compared to the lever escapement.
Dr. Daniels has sought cooperation with Patek Philippe (pp) and Rolex after the success of his research, which was rejected, and finally Omega boldly innovated and adopted Dr. Daniels' new escapement structure, which also enabled Omega to share the spoils with Rolex. So friends who like Omega are lucky, this patent currently belongs to Omega, no other manufacturer can have.
The Co-Axial escapement is quite complex compared to the traditional lever escapement. Omega's escapement transmission has been described by Daniels as "a very proper co-axial escapement". In the above illustration, the escapement wheel is no longer driven by a second wheel driving the teeth of the shaft.
(1) Instead, the seconds wheel drives a gear with five teeth.
(2) This gear drives the secondary escapement wheel.
(3) Upper part of the escapement wheel. (3) The lower part.
(4) The main escapement wheel is mounted on the same shaft as the secondary escapement wheel.
(5) Escapement lever.
The escapement lever fork tiles (6) and (7) lock and release the main escapement wheel only.
The third fork tile (8) is used to receive the transmission impulse from the secondary escapement wheel (9).
The escapement wheel transmits the impulse energy to the balance wheel in two ways.
One of the teeth (10) of the main escapement wheel pushes the output tile (7) to transfer the energy to the balance wheel (small figure A), which pushes the balance wheel to turn clockwise.
One tooth (9) of the secondary escapement wheel pushes the third fork tile (8) to transfer energy to the upper fork tile of the balance wheel (small figure B), which pushes the balance wheel in a counterclockwise direction, like a standard lever escapement.
The coaxial escapement is energized only by clockwise impacts, when the teeth of the escapement gear D directly engage the ruby impact stone J, and counterclockwise impacts, when the escapement pinion C engages the lever impact stone G. The escapement gear is then turned to the upper fork (8), which transmits energy to the upper fork of the balance wheel (small figure B). After each shock, the escapement wheel is secured by locking valves F and H, allowing the balance wheel to swing smoothly. The short sliding action reduces the contact surface and thus the friction within the escapement, so the escapement operates in a similar way to the way gears mesh with each other - meaning it requires less lubrication and still ensures a constant rate of timekeeping over the long term.
The above is the official answer, but as I work quite closely with Omega watches, here are my own thoughts on the Co-Axial escapement:
First of all, the Co-Axial escapement is a new and emerging technology, and while the principle is advanced, the technology isn't necessarily perfect.
Secondly, because it is an emerging technology, the co-axial escapement movement is not really a mature technology, and I feel that there is still room for improvement.
Lastly, the coaxial escapement accounts for the vast majority of Omega watches that are returned for repair
The coaxial escapement is the most important part of the Omega watch.