Bicycle outer chain link

An outer chain plate is configured to aid in downshifting such that a chain moves more smoothly from an outer chain ring (sprocket) to an inner chain ring (sprocket) with either no downshifting recess being provided on the outer chain ring or at least a shallower than normal downshifting recess being provided on the outer chain ring. At least a bottom part of the outer chain plate that faces a center axis of a sprocket when in use has a portion removed to minimize contact with outer chain ring when downshifting. Preferably, the bottom part of the outer chain plate has a chamfered outer edge portion along a cutout portion that defines a reduced area portion.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to bicycle chains. More specifically, the present invention relates to an outer link for a bicycle chain.

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. One component that has been recently redesigned is the bicycle chain.

Most bicycles have a drive train that uses a chain to transmit the pedaling action from the rider to the rear wheel. Bicycle chains have a plurality of inner links and a plurality of outer links that are interconnected in an alternating manner by a plurality of pins. Typically, each of the inner links includes a pair of parallel inner plates connected by a pair of parallel hollow cylinders or pins surrounded by cylindrical rollers. Each of the outer pin links includes a pair of parallel outer plates connected by the pins of the adjacent inner links. In order to form a single continuous chain, two of the inner links are connected together by a releasable connecting link, which is often called a master chain link. Examples of bicycle chains with a master link are disclosed in U.S. Pat. No. 5,362,282 to Lickton, U.S. Pat. No. 6,110,064 to Guichard, and U.S. Patent Publication No. 2002/0173395A1 to Reiter et al. Other examples of bicycle chains are disclosed in U.S. Pat. No. 5,741,196 to Campagnolo and U.S. Patent Publication No. 2005/0020394A1 to Valle.

When downshifting a chain from a large front chain ring to a smaller chain ring, the outer links of the chain sometime tend to contact the inside surface of the large front chain ring. Thus, some bicycle cranksets have been provided with downshifting recesses or indentations on the inside surface of the large front chain ring to aid in the downshifting from. While this arrangement works well. The manufacturing process for forming such a bicycle crankset requires additional manufacturing steps that can increase the cost of manufacturing the bicycle crankset. Also since these downshifting recesses or indentations are located adjacent the teeth, these downshifting recesses or indentations can also weaken the chain ring.

While these above-mentioned chains work well, it will be apparent to those skilled in the art from this disclosure that there exists a continual need for an outer chain link. This invention addresses this need in the 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 an outer chain link that can be used with a bicycle crankset having a large front chain ring that has no downshifting recesses or indentations are located adjacent the teeth or at least a shallower downshifting recesses or indentations as compared to prior bicycle crankset.

The foregoing objects can basically be attained by providing an outer chain link plate comprising first and second end portions and a connecting portion. The first and second end portions have at one least one pin coupling opening extending into the first and second end portions to define first and second pivot axes. The connecting portion connects the first and second end portions together with a longitudinal axis bisecting the least one pin coupling opening. The first and second end portions and the connecting portion define an outer peripheral edge. The at least one of the first and second end portions includes a side surface with a chamfered outer edge portion that extends along a section of the outer peripheral edge, and a first reduced area part that has a reduced radial dimension with respect to a radial dimension of a portion lying along the longitudinal axis. The radial dimensions are measured radially from an edge of the least one pin coupling opening to the outer peripheral edge along a line that extends from a corresponding one of the first and second pivot axes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring initially toFIG. 1, a bicycle10is illustrated that uses a bicycle chain12in accordance with a first embodiment of the present invention. The bicycle10includes, among other things, a drive train14that is configured to convert the rider's pedaling force into driving force. The chain12is part of the drive train14. The drive train14also includes a front crankset16, a rear sprocket assembly18, a front derailleur20and a rear derailleur22. The crankset16is mounted on a bottom bracket that is secured in a hanger on the bicycle frame in a conventional manner. The rear sprocket assembly18is mounted to a free wheel of the rear wheel in a conventional manner. The chain12is arranged on the crankset16and the rear sprocket assembly18so as to extend therebetween in a conventional manner. The derailleurs20and22are configured and arranged to change gears by shifting the chain12in a lateral direction of the bicycle10in a conventional manner.

Referring now toFIG. 2, the right side of the front crankset16will be briefly described. The right side of the front crankset16basically includes a right crank arm (gear crank)24with an outer chain ring26and an inner chain ring28. The front crankset16can be any known construction, and thus, will not be discussed and/or illustrated in detail herein. However, as explained below, the chain12of the present invention allows the outer chain ring26to be configured without deep downshifting recesses or indentions, and more preferably, to be configured without any downshifting recesses or indentions as shown.

Referring now toFIGS. 3 and 4, the chain12basically includes a plurality of inner link plates30, a plurality of first outer link plates31, a plurality of second outer link plates32, a plurality of pins or rivets33and a plurality of rollers34. The inner links30are interconnected in an alternating manner with the outer links31and32by the link pins33in a conventional manner. A master chain link (not shown) preferably interconnects two pairs of the inner plates30together so as to form a single continuous loop. The link plates30to33, the link pins33and the rollers34are metal parts that are well known in the bicycle chain field. Thus, the inner plates30, the link pins33and the rollers34are well known structures, and thus, they will not be discussed and/or illustrated in detail herein. Moreover, these parts can vary as needed and/or desired. For example, while the link pins33are illustrated as solid cylinders with a recess at each end so that the pins can be easily deformed that are deformed at each end, the link pins33can be hollow pins if needed and/or desired.

Referring now toFIGS. 4 to 15, the first and second outer link plates31and32will now be discussed in greater detail. When one of the first outer link plates31is coupled to one of the second outer link plates32by a pair of the link pins33, an outer chain link is formed. First, each of the first outer link plates31has been modified relative to a conventional outer link plate so that the first outer link plates31minimize contact with the outer chain ring26during a downshifting operation. Second, each of the second outer link plates32is preferably a conventional outer link plate. However, the second outer link plates32can be made to be identical to the first outer link plates31or can be made to include some of the features of the first outer link plates31.

Now referring now toFIGS. 8 and 10, each of the first outer link plates31includes a first end portion41, a second end portion42and a connecting portion43interconnecting the first and second end portions41and42. The portions41to43of each of the first outer link plates31are preferably formed as a one-piece, unitary member from a hard, rigid material such as a metallic material that is known to be used for manufacturing bicycle chains. Also the first end portion41also has a pin hole44for receiving one of the link pins33therein. Likewise, the second end portion42also has a pin hole45for receiving one of the link pins33therein. The ends of the link pins33are deformed for fixedly securing the first and second outer link plates31and32thereto. The pin holes44and45have center points that define first and second pivot axes P1and P2. A longitudinal axis A of the first and second outer link plates31and32bisects the connecting portion43and the pin holes44and45, i.e., passes through the pivot axes P1and P2of the pin holes44and45. While the pin holes44and45are illustrated as two separate and distinct pin holes constituting a first coupling hole and a second coupling hole, it will be apparent two those skilled in the art form this disclosure that a single elongated slot could be used to define the pin holes44and45. Thus, the term “coupling opening” should not be limited to a continuous circular hole that extends 360 degrees. Also while the connecting portion43is illustrated as being narrower than the first and second end portions41and42, it will become apparent to those skilled in the art from this disclosure that the connecting portion43can be equal to the widths of the first and second end portions41and42, if needed and/or desired.

Referring now toFIGS. 9 and 15, the first and second end portions41and42and the connecting portion43of the first outer link plate31define a first outer peripheral edge46located between opposite side surfaces of the first outer link plate31. The first outer peripheral edge46includes a first end edge section51, a second end edge section52and a pair of central edge sections53and54. The first end edge section51extends about the first end portion41of the first outer link plate31. The second end edge section52extends about the second end portion42of the first outer link plate31. The central edge sections53and54extend along the connecting portion43of the first outer link plate31between the first and second end portions41and42of the first outer link plate31.

As best seen inFIGS. 5 and 9, the first and second end portions41and42are smaller than the corresponding parts of the second outer link plate32. The configurations of the first and second end portions41and42of the first outer link plates31allow for a small clearance to occur between the teeth of the outer chain ring26and the first and second end portions41and42of the first outer link plates31to aid in the downshifting movement of the chain12. In other words, the configurations of the first and second end portions41and42of the first outer link plates31minimizes interference with the teeth of the outer chain ring26during the downshifting movement of the chain12. The first and second end portions41and42are preferably mirror images of each other. However, the first and second end portions41and42can be slightly different with first and second end portions41and42only being the mirror images of each other with respect to portions of the outer peripheral edge. In any event, since the first and second end portions41and42are mirror images of each other in the illustrated embodiment, only one of the first and second end portions41and42will be discussed in detail herein.

The first end portion41is provided with a chamfered (beveled) outer edge portion55that extends along a majority of the first end edge section51of the first outer peripheral edge46, while the second end portion42is provided with a chamfered (beveled) outer edge portion56that extends along a majority of the second end edge section52of the first outer peripheral edge46. The chamfered outer edge portions55and56are symmetrically arranged about the longitudinal axis A. Preferably, the chamfered outer edge portions55and56extend at least 180 degrees about their corresponding one of the pivot axes P1and P2. More preferably, the chamfered outer edge portions55and56extend at least 240 degrees about their corresponding one of the pivot axes P1and P2. The chamfered outer edge portions55and56are dimensioned such that the portion of the chain12located between the outer chain ring26and the inner chain ring28minimizes interference with the inside face of the outer chain ring26and/or the adjacent tooth of the outer chain ring26during the downshifting movement of the chain12.

As best seen inFIG. 15, the first and second end edge sections51and52of the first outer peripheral edge46of the first and second end portions41and42are non-semicircular about the longitudinal axis A. The first end edge section51of the first outer peripheral edge46includes a middle part51alocated at the longitudinal axis A and a pair of flat parts51bextending from the middle edge part51a. Likewise, the second end edge section52of the first outer peripheral edge46includes a middle part52alocated at the longitudinal axis A and a pair of flat parts52bextending from the middle edge part52a. The middle edge parts51aand52aare preferably curved surfaces with their centers offset towards the middle of the first outer link plate31from their corresponding one of the pivot axes P1and P2. The flat edge parts51bare angled at ninety-five degrees (i.e., substantially ninety degrees) apart relative to each other about the longitudinal axis A. Likewise, the flat edge parts52bare angled at ninety-five degrees (i.e., substantially ninety degrees) apart relative to each other about the longitudinal axis A. Thus, the first end portion41has a large area part41adefined by the middle edge part51aof the first outer peripheral edge46located at the longitudinal axis A and a pair of reduced area parts41bdefined by the flat edge parts51bof the first outer peripheral edge46. Similarly, the second end portion42has a large area part42adefined by the middle edge part52aof the first outer peripheral edge46located at the longitudinal axis A and a pair of reduced area parts42bdefined by the flat edge parts52bof the first outer peripheral edge46. In particular, the reduced area parts41band42bhave reduced radial dimension R1with respect to radial dimensions R2of the middle edge parts51aand52a(i.e., the portions of the first and second end portions41and42that lie along the longitudinal axis. These radial dimensions R1and R2are measured radially from an edge of their corresponding one of the pin holes44and45to the outer peripheral edge along a line that extends from a corresponding one of the first and second pivot axes P1and P2.

While the first outer link plates31are illustrated as being symmetrical about the longitudinal axis A and the first and second end portions41and42being mirror images of each other, the first outer link plates31can be configured such that the reduced area part and the chamfered outer edge portion are only disposed along a bottom area of the outer peripheral edge that faces a center axis of the outer chain ring26when in use.

As best seen inFIGS. 4 and 5, the first and second end portions41and42are smaller than the corresponding parts of the second outer link plate32. The configurations of the first and second end portions41and42of the first outer link plates31allow for a small clearance to occur between the teeth of the outer chain ring26and the first and second end portions41and42of the first outer link plates31to aid in the downshifting movement of the chain12. In other words, the configurations of the first and second end portions41and42of the first outer link plates31minimizes interference with the teeth of the outer chain ring26during the downshifting movement of the chain12.

Similar to the first outer link plates31, each of the second outer link plates32includes a first end portion61, a second end portion62and a connecting portion63interconnecting the first and second end portions61and62. However, the first and second end portions61and62are larger than the first and second end portions41and42of the first outer link plate31. The portions61to63of each of second outer link plates32are preferably formed as a one-piece, unitary member from a hard, rigid material such as a metallic material that is known to be used for manufacturing bicycle chains. Also the first end portion61also has a pin hole64for receiving one of the link pins33therein. Likewise, the second end portion62also has a pin hole65for receiving one of the link pins33therein. The ends of the link pins33are deformed for fixedly securing the first and second outer link plates31and32thereto. In other words, a first one of the link pins33connects the first end portions41and61of the first and second link plates31and32together, and a second one of the link pins33connects the second end portions42and62of the first and second link plates31and32together.

Referring again toFIGS. 4 and 5, the first and second end portions61and62and the connecting portion63of the second outer link plate32define a second outer peripheral edge66located between opposite side surfaces of the second outer link plate32. The second outer peripheral edge66includes a first end edge section71, a second end edge section72and a pair of central edge sections73and74. The first end edge section71extends about the first end portion61of the second outer link plate32. The second end edge section72extends about the second end portion62of the second outer link plate32. The central edge sections73and74extend along the connecting portion63of the second outer link plate32between the first and second end portions61and62of the second outer link plate32.

As best seen inFIGS. 4 and 5, the first and second end edge sections71and72of the first and second end portions61and62are at least semicircular, and more preferably extend 240 degrees along a singe arc. Thus, the overall shape of the first and second end portions61and62is larger than the first and second end portions41and42of the first outer link plates31. The term “semicircular” as used herein refers to an arc that is equal one half of a circle.

Thus, the first and second end edge sections71and72of the second outer peripheral edge66of the first and second end portions61and62are dimensioned such that the overall length of the second outer link plates32is approximately 0.6 millimeters longer than the first outer link plates31for a conventional bicycle chain.

GENERAL INTERPRETATION OF TERMS