Post by mamas on Oct 26, 2005 7:03:16 GMT -6
Guys, with the permission of the author Jean Michel, moderator of WUS omega forum i post one of the best articles i have read conerning the co-axial movement that he has authored.
Please also take time to visit his speedmaster mission website, one of the best speedy web sites on the web (http://www.speedmaster-mission.net/)
Thank you JM.
The Co-Axial escapment has been invented and pattended by George Daniels, famous English watchmaker , winner of many national and international awards, including the prestigious Tompion Gold Medal and and Gold medal of the British Horlogical institute . George Daniels is concidered as the greatest living horlogist
The main advantage of the co-axial escapment is offering less friction during operation needing no (or extremly little) lubrification of escpament parts , resulting longer periods between maintenance and a better accuracy on long time period
The main difference between the Swiss lever escapment and the Co-Axial escapment is the type of frictions : on the swiss lever escapment the design relies on sliding friction as the escape wheel impulse surfaces sweep over the pallets to power the balance. Sliding friction means lubrication, and lubrication has always been the Achille's heel of the lever escapement.
George Daniels has been pursuing a single objective: the elimination of lubrication at the impulse surface. In the co-axial escapement, this is accomplished with a largely rolling (as opposed to sliding) impulse to the balance (see the escapment in motion at the end of the article)
Technical details :
The energy to maintain the free sprung-balance is transmitted by an escapement whose energy transmission is obtained by the tangential motions of the parts.
The escapement is composed of an intermediary wheel A, a double Coaxial wheel B composed of escapement pinion C and escapement wheel D, pallet fork E with 3 ruby pallet-stones F, G,H and a balance roller K carrying a ruby impulse stone J and a ruby impulse pin L. The roller is fitted to the sprung balance.
It is essential that a successful escapement for use in a modern watch must transmit energy to the oscillator in both clockwise and anti-clockwise vibrations.
In the Coaxial escapement, the clockwise impulse is delivered to the oscillator directly by the escape wheel engaging the balance roller. The anti-clockwise impulse is delivered to the balance roller via the lever. After each impulse, the escape wheel is locked stationary by the lever locking pallets allowing the balance to complete its vibration undisturbed.
The balance roller K turning Clockwise to unlock tooth a from entry pallet F.
Clockwise impulse to balance roller K by tooth b on roller pallet J.
The balance turning anti-clockwise to unlock tooth c from exit pallet H.
Anti-clockwise impulse to balance roller K via tooth d of pinion C and lever impulse stone G.
Here are some images to show you the co-axial movement in motion compared to the classical anchor escapment
The Co-Axial : (image from abbeyclock.com)
The Anchor or Swiss lever (image from abbeyclock.com)
Please also take time to visit his speedmaster mission website, one of the best speedy web sites on the web (http://www.speedmaster-mission.net/)
Thank you JM.
The Co-Axial escapment has been invented and pattended by George Daniels, famous English watchmaker , winner of many national and international awards, including the prestigious Tompion Gold Medal and and Gold medal of the British Horlogical institute . George Daniels is concidered as the greatest living horlogist
The main advantage of the co-axial escapment is offering less friction during operation needing no (or extremly little) lubrification of escpament parts , resulting longer periods between maintenance and a better accuracy on long time period
The main difference between the Swiss lever escapment and the Co-Axial escapment is the type of frictions : on the swiss lever escapment the design relies on sliding friction as the escape wheel impulse surfaces sweep over the pallets to power the balance. Sliding friction means lubrication, and lubrication has always been the Achille's heel of the lever escapement.
George Daniels has been pursuing a single objective: the elimination of lubrication at the impulse surface. In the co-axial escapement, this is accomplished with a largely rolling (as opposed to sliding) impulse to the balance (see the escapment in motion at the end of the article)
Technical details :
The energy to maintain the free sprung-balance is transmitted by an escapement whose energy transmission is obtained by the tangential motions of the parts.
The escapement is composed of an intermediary wheel A, a double Coaxial wheel B composed of escapement pinion C and escapement wheel D, pallet fork E with 3 ruby pallet-stones F, G,H and a balance roller K carrying a ruby impulse stone J and a ruby impulse pin L. The roller is fitted to the sprung balance.
It is essential that a successful escapement for use in a modern watch must transmit energy to the oscillator in both clockwise and anti-clockwise vibrations.
In the Coaxial escapement, the clockwise impulse is delivered to the oscillator directly by the escape wheel engaging the balance roller. The anti-clockwise impulse is delivered to the balance roller via the lever. After each impulse, the escape wheel is locked stationary by the lever locking pallets allowing the balance to complete its vibration undisturbed.
The balance roller K turning Clockwise to unlock tooth a from entry pallet F.
Clockwise impulse to balance roller K by tooth b on roller pallet J.
The balance turning anti-clockwise to unlock tooth c from exit pallet H.
Anti-clockwise impulse to balance roller K via tooth d of pinion C and lever impulse stone G.
Here are some images to show you the co-axial movement in motion compared to the classical anchor escapment
The Co-Axial : (image from abbeyclock.com)
The Anchor or Swiss lever (image from abbeyclock.com)
