Wheel and pinion assembly with friction drive/slip coupling for a timepiece
US5155712A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 20, 1992 |
| Grant date | Oct 13, 1992 |
| Priority date | — |
| Expiry date | Apr 20, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG04B13/023
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An improved reduction gear assembly with friction drive/slip coupling for a timepiece movement, comprising a metal pinion member having a toothed pinion and a coaxial stem extending from an abutment surface on said pinion, including (1) a cylindrical portion, (2) a frustum portion tapering from a smaller diameter to a larger diameter (3) a terminating tapered end portion; and a plastic wheel member having a toothed wheel and first and second coaxial journals extending from opposite sides of the. A central passage in the journals has a constricted section therein with a diameter slightly less than that of said larger diameter of said frustum portion on said metal pinion member with the frustum disposed in said constricted passage with a snap fit, whereby a friction drive/slip coupling is provided between the metal frustum portion of the metal pinion member and the constricted passage of the plastic wheel member.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.