Planetary gear transmission systems or components – With means to vary drive ratio or disconnect drive – Plural elements selectively braked
Reexamination Certificate
1998-11-05
2001-11-06
Bucci, David A. (Department: 3682)
Planetary gear transmission systems or components
With means to vary drive ratio or disconnect drive
Plural elements selectively braked
C475S298000, C192S217400
Reexamination Certificate
active
06312355
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention is directed to bicycle transmissions and, more particularly, to an internal bicycle transmission that shifts gears when a driving member is in a predetermined rotational position.
Internal bicycle transmissions commonly have planet gear mechanisms. A planet gear mechanism comprises a gear ring, a sun gear, planet gears meshing with the gear ring and sun gear, and a carrier for supporting the planet gear. It is known that internal bicycle transmissions having such planet gear mechanisms are used to shift gears by selectively locking or unlocking any of the constituent elements of the planet gear mechanism with the aid of a clutch mechanism having lock pawls. The lock pawls are forcibly moved in the unlocking direction by a clutch-actuating mechanism that has a receiving hole for accepting the tips of the lock pawls.
When the lock pawls of the clutch mechanism are in a locked state and it is desired to change gears, a large force is needed to release the lock pawls at a time when the transmission is subjected to a driving force. Thus, the gear shifting operation is strenuous and difficult to perform unless the cyclist stops pedaling, thus increasing the complexity of the shifting operation.
Japanese Unexamined Patent Application 64-18792 describes a front shifting device designed to facilitate gear shifting so that gears can be shifted during pedaling. This front shifting device has a clutch pawl for switching the lock pawls between a locked position and an unlocked position. The clutch pawl is actuated by a clutch-actuating mechanism, and the lock pawls are forcibly actuated in the unlocking direction. However, the lock pawls are actuated indirectly via the clutch pawl rather than being actuated directly by the clutch-actuating mechanism. As a result, the mechanism for performing gear shifting is complicated., and the overall weight and cost of the transmission is increased.
SUMMARY OF THE INVENTION
The present invention is directed to an internal bicycle transmission that is easy to shift even while pedaling, wherein the transmission has a simpler structure than known transmissions. The invention can be applied to an internal transmission attached to the front crank arms, to an internal transmission forming part of a wheel hub, or to any similar transmission.
In one embodiment of the present invention, a bicycle shifting device includes a driver, a slave, a power transmission mechanism coupled between the driver and the slave for communicating rotational power from the driver to the slave through a plurality of power transmission paths, and a clutch for selecting one of the plurality of power transmission paths in the power transmission mechanism. A clutch actuating mechanism causes the clutch to select the one of the plurality of power transmission paths when the driver is at a predetermined rotational position. If desired, the predetermined position may be a position where a strong drive force is not being applied to the driver. In that case it may be desirable to have the clutch actuating mechanism cause the clutch to select each of the plurality of power transmission paths only when the driver is at the predetermined rotational position.
REFERENCES:
patent: 3021728 (1962-02-01), Shimano
patent: 4854191 (1989-08-01), Nagano
patent: 5152720 (1992-10-01), Browning et al.
patent: 5303942 (1994-04-01), Schlumpf
patent: 5399128 (1995-03-01), Nurnberger
patent: 5562563 (1996-10-01), Shoge
patent: 5609071 (1997-03-01), Schlumpf
patent: 5769750 (1998-06-01), Rickels
patent: 5829563 (1998-11-01), Shoge
patent: 531608 (1993-03-01), None
patent: 687622 (1995-12-01), None
patent: 2208901 (1989-04-01), None
patent: 2295427 (1996-05-01), None
patent: 62-99293 (1987-05-01), None
patent: 64-18792 (1989-01-01), None
Bucci David A.
Charles Marcus
Deland James A.
Shimano Inc.
LandOfFree
Bicycle transmission that shifts when a driver is in a... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Bicycle transmission that shifts when a driver is in a..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Bicycle transmission that shifts when a driver is in a... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2587884