Browning Automatic Transmission
The Browning Automatic Transmission is a bicycle transmission that is far superior to current designs. The product sports an automatic shifting design in that the bicycle computer will automagically determine what gear to be in based on spoke and hub magnet counts. In addition to that, the shifting mechanism is a radical improvement over the standard derauiller design. For those who like control, the system can be shifted into a fully manual mode.
There is currently a 4-speed version of the bicycle slated for market release
to multiple vendors as well as a 12-speed number in the works
Browning Automatic Bicycles is a company owned in part by the former owners of Browning Automatic Rifles
(or just Browning
) for short. The company
owns several sub-orginizations:
- Browning Component
- which is responsible for the machine shop as well as the distribution/manufacture of the transmission.
- Browning Research
- Which is in the business of general R&D with the Automatic Transmission still as their main project
Some info on the bike
The major ideas Browning Research develop
ed include a replacement
for the age-old derailleur
system used to change gears
since the 1800s
. The gearset
actually changes into an effective spiral
allowing the chain to ride
up the gearset
. It shifts wonderfully
under load and is beautiful
to watch. The Browning crew
have termed the thingie
Basically, the selector works by tripping a one-time cam so that springs pull the guide
either left or right. The selector guides a small metal tab that is attached to the gearset either direction, spiralling the gears in that direction. As the tab hits the guide, it pushes the selector back to the middle as it shifts. The 4-speed bike transmission is good for approximately 50,000 shifts before depleting the battery (a simple 9-volt cell).
The bike computer uses hysteresis to keep from dithering from gear to gear; it also has a system whereby you can tell it to change gears in automatic mode and it will remember to change to selected gear under similar conditions if possible.
- The browning computer uses an 8051-based controller (Phillips is the current manufacturer used)
- Browning Automatic Rifles made a 10-speed bicycle before the Browning family left the company; that bicycle was used as a testbed for the first gearset designs.
- The first design of the shifting mechanism had no smarts; in fact it was purely mechanical
- The bicycle prototypes proved to be a major advantage during Olympic Racing trials; professional bikers shaved seconds off currently held world records.
The bike was unfortunately banned from the Olympics under a technicality; which is just as well, the US would have won hands down had it been introduced
They have the following patents (all viewable from Delphion)
Oddly enough, they managed to get away with patenting hysteresis, so don't do it or get sued