Endless belt power transmission systems or components – Positive drive pulley or guide roll – And additional coaxial surface for engaging same belt in...
Reexamination Certificate
2001-11-07
2002-09-17
Bucci, David A. (Department: 3682)
Endless belt power transmission systems or components
Positive drive pulley or guide roll
And additional coaxial surface for engaging same belt in...
C474S144000
Reexamination Certificate
active
06450909
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention generally relates to a bicycle front chainwheel assembly which fixedly couples a bicycle pedal to the bicycle bottom bracket and supports one or more chainrings thereon. More specifically, the present invention,is directed to a protective cover that is coupled to the front chainwheel.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has also become a very popular competitive sport. Whether the bicycle is used for recreation, transportation or competition, the various bicycle components are constantly being improved to increase performance and/or safety. Moreover, bicycle components are constantly being designed so as to be more durable and attractive. One particular portion of a bicycle that has been extensively redesigned over the past years is the drive train of the bicycle.
The drive trains of most of today's bicycles have multiple speeds that allow the rider to select the appropriate gear ratio to suit the particular riding conditions encountered during the bicycle ride. One of the most popular types of gearing assemblies for multi-speed bicycles utilize a chain extending between a set of front chainrings or chainwheels, and a set of rear gears or sprockets mounted on the rear hub of the rear bicycle wheel. Two derailleurs are typically used to move the chain between the chainrings or sprockets. The pedals are coupled to the front chainrings or for rotation therewith by a pair of bicycle crank arms coupled to a bottom bracket. The crank arms extend outwardly from the bottom bracket in opposite directions and have pedals attached to their free ends for supporting the rider's feet. Rotation of the pedals by the rider causes the chainrings to rotate which in turn moves the bicycle chain to rotate the rear sprockets, and thus, rotate the rear wheel of the bicycle. In certain crank arm designs, the front chainrings are coupled directly to the crank arm by fastening finger portions. The fastening finger portions are coupled to the hub portion of the crank arm, and extend radially outwardly from the hub portion of the crank arm.
One problem with these types of drive trains is that the rider's clothing can either get caught in-between the chain and the chainring, or the rider's clothing can become dirty from contacting these chains. Another problem with these types of chain drives is that the chain can pop off of the chainring due to improper adjustment of the drive train.
To overcome these problems, bicycle manufactures have provided a protective cover or guard for the driving sprocket of a bicycle. Usually, such covers or guards have been made of resin or some other soft material. It is very difficult to manufacture a protective cover or guard made of a soft material with precise dimensions. Even if the protective cover or guard is manufactured with very precise and accurate dimensions, the soft material of the protective cover can be easily distorted or damaged by heat, pressure or other environmental factors. Thus, prior protective covers tend to be constructed without precise and accurate dimensions. This often results in wobbling of the conventional protective cover. In particular, if one portion of the protective cover is distorted for some reason, when it is attached to the front chain wheel, the distorted portion (usually one of the corners) can be lifted up even though both of the bolts are securely fixed to the front chain wheel.
One method to overcome this problem is to construct the protective cover from a heavy, rigid metallic material. However, this is very undesirable since bicycles should be constructed as lightweight as possible. Other attempts to overcome this problem have resulted in very unattractive protective covers and/or protective covers that limit the design options for the crankset.
Most protective covers or guards are fixed to the front chainwheel by bolts extending in a direction relatively parallel to the axis of rotation of the chainwheel. Thus, these prior art types of protective covers cannot be adjusted in the axial direction to correct for wobbling. Moreover, when the prior art protective covers become distorted, they often result in a very unattractive appearance. Also, the fasteners are often located on the front or outer surface of the front chainwheel, which results in a less attractive appearance. In particular, it is desirable to create a front chainwheel that has a very smooth attractive appearance without the fasteners being seen on the front surface.
Another problem with many prior art protective covers or guides is that the attachment points for the protective cover limit the design of the fastening fingers and/or the chainring. In particular, it is desirable to have a front chainwheel with a protective cover that has the same degree for freedom for design as a front chainwheel that does not have a protective cover.
In view of the above, there exists a need for a front chainwheel assembly which overcomes the above mentioned problems in the prior art. This invention addresses this need in the prior art as well as other needs, which will become apparent to those skilled in the art from this disclosure.
SUMMARY OF THE INVENTION
One object of the present invention is to provide a protective cover, which is attractive as well as provide proper protection for the chainrings and the chain.
Another object of the present invention is to provide a front chainwheel assembly that is relatively easy to install and to adjust for avoiding wobbling of the cover.
Another object of the present invention is to provide a front chainwheel assembly that has a smooth transition between the front surfaces of the cover and the fastening finger portions.
Another object of the present invention is to provide a front chainwheel assembly that allows for more freedom of design of the crankset.
Another object of the present invention is to provide a cover for a front chainwheel assembly which is relatively easy and inexpensive to manufacture.
Still another object of the present invention is to provide a bicycle front chainwheel assembly which is lightweight and strong.
The foregoing objects can basically be attained by providing a bicycle front chainwheel assembly having a bicycle front chainwheel assembly comprising a hub portion configured to be coupled to a bottom bracket for rotation therewith about an axis of rotation; a crank portion having an inner end coupled to the hub portion and an outer free end adapted to be coupled to a pedal; and a plurality of fastening finger portions extending radially outwardly from the hub portion to free ends, each of the fastening finger portions having a chainring attachment point; and a cover coupled to the fastening finger portions by fasteners having a shaft portion extending substantially perpendicular to the axis of rotation.
These and other objects, features, aspects and advantages of the present invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention.
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Bucci David A.
Hansen Colby
Shimano Inc.
Shinjyu Global IP Counselors, LLP
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