To provide a bicycle gear crank that avoids the shape of a crank chain ring from being changed and is suitable for increasing the number of stages of a sprocket.SOLUTION: A bicycle gear crank A1 is provided with: a crank arm 1 including a boss part 11 for attaching a crank shaft; a large-diameter chain ring 2 including a ring-shaped main body part 21 and plural teeth 22 disposed on the outer circumference of the ring-shaped main body part 21 at equal pitches in a state in which interdental parts 23 are interposed between the teeth 22; and a small-diameter chain ring 3 including a ring-shaped main body part 31 and plural teeth 32 disposed on the outer circumference of the ring-shaped main body part 31 at equal pitches in a state in which interdental parts 33 are interposed between the teeth 32, located side by side with the large-diameter chain ring 2, and having the number of teeth smaller than that of the large-diameter chain ring 2. Detachable screw members 4 located radially outward of a pitch diameter C1 of the small-diameter chain ring 3 as viewed in the direction of the crank shaft are attached on an inner surface 21A of the ring-shaped main body part 21, facing the small-diameter chain ring 3.SELECTED DRAWING: Figure 2

    【課題】チェーンリングの形状変更を回避し、スプロケットの多段化に対応するのに適した自転車用ギアクランクを提供する。【解決手段】クランク軸取付用のボス部11を有するクランクアーム1と、リング状本体部21、およびリング状本体部21の外周において歯間部23を挟んで等ピッチで配列された複数の歯22、を有する大径チェーンリング2と、リング状本体部31、およびリング状本体部31の外周において歯間部33を挟んで等ピッチで配列された複数の歯32、を有し、大径チェーンリング2と並び、かつ大径チェーンリング2よりも歯数が少ない小径の小径チェーンリング3と、を備えた自転車用ギアクランクA1であって、リング状本体部21において小径チェーンリング3側を向く内側面21Aには、クランク軸方向に見て小径チェーンリング3のピッチ円直径C1よりも径方向外側に位置する、着脱可能なネジ部材4、が取り付けられている。【選択図】図2


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    Title :

    BICYCLE GEAR CRANK AND CHAIN RING


    Additional title:

    自転車用ギアクランク、およびチェーンリング


    Contributors:

    Publication date :

    2020-07-09


    Type of media :

    Patent


    Type of material :

    Electronic Resource


    Language :

    Japanese


    Classification :

    IPC:    B62M RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES , Antrieb von Radfahrzeugen oder Schlitten durch den Fahrer



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