Machine element or mechanism – Elements – Cranks and pedals
Reexamination Certificate
1999-05-26
2002-09-24
Luong, Vinh T. (Department: 3682)
Machine element or mechanism
Elements
Cranks and pedals
C074S594400
Reexamination Certificate
active
06453771
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to a bicycle pedal. More specifically, the present invention relates to a clipless or step-in bicycle pedal having a tread cage.
2. Background Information
Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle as well as the frame of the bicycle. One component that has been extensively redesigned is the bicycle pedal.
In recent years, bicycle pedals have been designed for specific purposes such as for pleasure, off road biking, road racing, etc. One particular type of bicycle pedal, which is gaining more popularity, is the step-in or clipless pedal, which releasably engages a cleat secured to the sole of a cyclist's shoe. The clipless pedal has a pedal spindle that can be mounted on the crank of a bicycle, a pedal body that is rotatably supported on this pedal spindle, and a cleat engagement mechanism. In an off road bicycle pedal a cleat engagement mechanism is formed on both sides of the pedal body for engaging a cleat. Road racing pedals, on the other hand, typically only has a cleat engagement mechanism on one side of the pedal body. In either case, in this type of bicycle pedal, the rider steps onto the pedal and the cleat engagement mechanism automatically grips on to the cleat secured to the bottom of the cyclist's shoe.
When attaching the cyclist's shoe to the step-in or clipless pedal via the cleat, the cyclist moves the shoe obliquely downwardly and forwardly relative to the pedal body such that the front end of the cleat engages a front hook or clamping member of the pedal body. Once the front end of the cleat is engaged with the front hook of the pedal body, the cyclist places the rear end of the cleat in contact with a guide portion of the rear hook or clamping member of the pedal body. In this position, the cyclist presses the shoe downwardly against the pedal to cause the rear hook or clamping member to initially pivot rearwardly against the force of a spring to move the rear hook or clamping member to a cleat releasing position. The rear end of the cleat then enters a position opposite a back face of the rear hook or clamping member. Then, the rear hook or clamping member returns under the force of a biasing member or spring so that the rear hook or clamping member engages the rear end of the cleat. This engagement fixes the cyclist's shoe to the pedal via the cleat.
When releasing the shoe from the pedal, the cyclist will typically turn the shoe about an axis perpendicular or approximately perpendicular to the tread of the pedal, using the front end of the cleat as a pivoting point. As a result of this pivoting action, the rear hook or clamping member is pivoted rearwardly against the force of the spring to a cleat releasing position to release the shoe.
With this type of step-in or clipless pedal, the shoe and the pedal are in a state of constant engagement when the cleat clamping is engaged in the cleat clamping members, so the pedaling force can be transmitted efficiently to the pedals. As a result, step-in or clipless pedals are widely employed on racing bicycles used in road racing and mountain bike racing.
One problem with most step-in or clipless pedals is that they are quite small such that only small portions of the pedal body engage the rider's shoe. Specifically, the pedal body has a tread surface located on both sides of the cleat engagement mechanism. This tread surface has only a small surface area because the pedal body is typically made as small as possible so that it will be lightweight. Thus, it is often difficult to apply a pedaling force when the cleat is not engaged.
Furthermore, with off-road racing the foot must be repeatedly taken off the pedal during cornering and replaced on the pedal after the corner has been exited. Unfortunately, since the racing is performed on unpaved roads, mud clings to the pedals and tends to clog the clamping members. Once the clamping members become clogged with mud, the cleat cannot be engaged in the clamping members, and the shoe cannot be attached to the pedal. Moreover, the mud often clogs the biasing mechanism such that the clamping members may not operate properly.
When a cleat cannot be engaged with the cleat engagement members because of mud clogging, or when the feet are frequently removed from the pedals, the rider must often step on the pedal without the cleat being engaged in the cleat engagement members. However, since the pedal body of the above-mentioned conventional clipless pedals has as small a volume as possible and has only a small tread surface, the foot would slip around to the left and right when the cleat was not engaged with the cleat engagement members. As a result, the pedaling force is not transmitted efficiently to the pedals, and the speed of the bicycle drops. Lower speed is a critical problem for a racer. Accordingly, when it is expected that the pedals will become clogged with mud or the shoes will be taken off and replaced on the pedals frequently in this type of off-road race, more and more riders are using ordinary double-sided pedals rather than clipless pedals. Such pedals have no cleat engagement members, but they provide a good grip to the shoes. However, in either case, the cyclist does not have an optimum apparatus for pedaling the bicycle.
For a clipless pedal to be usable in such muddy situations, it must be possible for the rider to firmly step on the pedal even when the cleat is not engaged with the cleat engagement members. One possible means for achieving this could be to provide a wide tread cage on the pedal around the outside of the cleat engagement members so that more tread surface can come into contact with the shoe sole. However, if a wide tread cage is provided around the outside of the cleat engagement members, then the tread cage will interfere with the shoe sole and get in the way when the cleat is being engaged with the cleat engagement members. This may result in difficulties in engagement of the cleat with the pedal. Consequently, when the shoe is inserted from a direction other than the engagement direction, it will be difficult to reengage the cleat with the cleat engagement members quickly even if there is no mud clogging or the like.
Accordingly, step-in pedals have been designed with tread cages that have a small range of pivotal movement between the tread cage and the pedal body. In such an arrangement, tread cage is biased relative to the pedal body by a torsion spring. These bicycle pedals are provided with front and rear cleat engaging members that are coupled to the pedal for engaging corresponding front and rear portions of the cleat. A tread cage having a relatively wide tread surface is coupled to the pedal for movement relative to at least one of the front cleat engaging members or rear cleat engaging members. The wide tread surface provides stable contact between the cycling shoe and the pedal when the cleat is disengaged from the cleat engaging members. The movable tread cage allows the tread surface to move away from the cleat engaging members so as not to interfere when the cyclist is in the process of engaging the cleat with the cleat engaging members. The torsion spring is coupled between the tread cage and the pedal body to hold the tread cage in the appropriate position. While these prior art step-in pedals work very well, the torsion spring can fail over an extended period of time. Moreover, the torsion spring increases the costs of manufacturing the pedal.
In these prior pedals, the tread cage is typically constructed of a hard rigid material such as a metal alloy or a hard plastic material. Since pedals with tread cages are typically used in off road riding or down hill racing, the pedal and tread cage are
Takahama Kimitaka
Ueda Yutaka
Luong Vinh T.
Shimano Inc.
Shinjyu Global IP Counselors, LLP
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