Bicycle gear shifting method and apparatus
US4900291A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 5, 1989 |
| Grant date | Feb 13, 1990 |
| Priority date | — |
| Expiry date | Jan 5, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T74/2078
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
A bicycle derailleur gear shifting system having a rotatable handgrip actuator cam which is coupled with the derailleur shifting mechanism through a control cable system so as to control the derailleur mechanism. Separate actuator cams are associated with the front and rear derailleurs. For the down-shifting direction, at least the rear derailleur cam is configured so as to substantially compensate for increasing force of the derailleur return spring; so as to substantially compensate for numerous cumulative lost motions in the derailleur shifting mechanism and cable system, and for chain gap variations; and so as to overshift the chain a sufficient amount beyond the destination freewheel sprocket so that the chain will approach the destination sprocket in the same direction as it would in the up-shift direction, but not sufficient to cause a double shift, or derailling from the #1 sprocket. A front derailleur cam is configured to provide fine-tuning for "cross-over" riding.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.