Abstract A miniature gear drive, such as that used in clockworks, is disposed in one chamber of a housing having two chambers interconnected by a capillary channel. The chamber containing the gears is sealed except for the channel, and the entire assembly immersed in a lubricant liquid within a vacuum chamber. The vacuum chamber is evacuated and then the vacuum removed so that the lubricant completely fills both chambers of the housing. The assembly is removed from the vacuum chamber and heated whereby the liquid expands and a portion of the liquid escapes through an opening in the second housing chamber. The assembly is then cooled so that an air bubble is formed in the second housing chamber, and the second chamber is then sealed. The input power to the gear drive, and the output power therefrom are obtained by magnetic coupling through the housing. The air bubble permits expansion of the liquid within the housing due to temperature changes, but the capillary channel prevents this bubble from reaching the chamber containing the gear drive hence the gears are always completely immersed in the liquid.
A low friction miniature gear drive for use in transmitting forces from a power source to a dial train in a watch, said gear drive comprising: a housing having a closed gear train chamber; a gear train disposed with said chamber; a liquid in said gear train chamber completely immersing said gear train; said gear train including an input shaft and an output shaft located entirely within the housing; first and second magnetic coupling discs mounted on said input and output shafts, respectively; drive means; a ratchet which rotably driven by said drive means and disposed outside of said housing but adjacent to said first magnetic coupling disc, said ratchet wheel having mounted thereon magnetic means whereby rotary motion of said ratchet wheel is magneticAlly transmitted to said gear drive through said housing; and, a further magnetic coupling disc located outside of said housing adjacent said second coupling disc whereby motion of said gear train and second coupling disc is magnetically coupled to said further disc.
Claim 2
Dependent Claim
166 words
A low friction miniature gear drive for use in transmitting forces from a power source to a dial train in a watch, said gear drive comprising: a housing having a closed gear train chamber; a gear train disposed with said chamber; a liquid in said gear train chamber completely immersing said gear train; said gear train including an input shaft and an output shaft located entirely within the housing; first and second magnetic coupling discs mounted on said input and output shafts, respectively; drive means; a ratchet which rotably driven by said drive means and disposed outside of said housing but adjacent to said first magnetic coupling disc, said ratchet wheel having mounted thereon magnetic means whereby rotary motion of said ratchet wheel is magneticAlly transmitted to said gear drive through said housing; and, a further magnetic coupling disc located outside of said housing adjacent said second coupling disc whereby motion of said gear train and second coupling disc is magnetically coupled to said further disc.
Claim 3
Dependent Claim
22 words
A low friction miniature gear drive as claimed in claim 1 and further comprising a dial train driven by said further disc.
Claim 4
Dependent Claim
19 words
A low friction miniature gear drive as claimed in claim 1 wherein said drive means is a vibratory motor.
Claim 5
Dependent Claim
19 words
A low friction miniature gear drive as claimed in claim 1 wherein said drive means includes a tuning fork.
Claim 6
Dependent Claim
19 words
A low friction miniature gear drive as claimed in claim 1 wherein said drive means includes a quartz crystal.