Rear hub drive engagement mechanism
US5964332A · kind A · utility
Inventor
Key dates
| Filing date | Aug 27, 1997 |
| Grant date | Oct 12, 1999 |
| Priority date | — |
| Expiry date | Aug 27, 2017 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16D41/36
- WIPO fieldMechanical elements
- WIPO sectorMechanical engineering
Abstract
An engagement mechanism is provided within the rear hub of a bicycle to allow drive sprockets attached to the rear hub to transmit drive motion from the crankset to the rear wheel. The assembly uses a pair of engaging face gears with saw tooth-shaped teeth to accomplish the torque transfer/freewheeling. While one gear is in a fixed axial position, the other is allowed to move axially along a helical spline. A light spring backs up this moveable gear to hold it against the other. When the moveable gear is rotated in one direction, the teeth having their faces parallel to the axis push against each other squarely, transferring the rotating motion from one to the other. Yet in the other direction of rotation, the faces of the teeth are askew to the axis forming ramps by which the fixed gear pushes the moveable gear away from it along the axis. This allows the teeth of the moveable gear to jump over the teeth of the fixed gear causing no rotating force to be transferred to the other and thus freewheeling. The helical spline acts like a screw thread; in the engaging direction of rotation, it pulls and clamps the movable gear to the fixed gear. Once engaged, the helix continues to apply …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.