Title of Invention

BICYCLE CRANK ARM

Abstract Abstract of the Disclosure A bicycle crank ana assembly for a bicycle is disclosed heron which is designed for mounting a sprocket thereto. The crank ann has a centrally located hub portion, a crank portion extending radially outwardly from the bub portion and at least three fastening fingers extending radially outwardly from the hub portioa The fastening fingers are designed to have substantially the same stiffness at their free ends. This can be accomplised b a variety of ways such as change the across-section of the fiistening fingers adjacent the crank portion or changing the shape of the sprocket mounting portions of the fastening fingers. Also, in certain embodiments the fasstening fingers adjacent the crank portion are constructed such that their rear surfaces lie m the same plane as the rear surface of the crank portion adjacent thereto, or in a lower plane.
Full Text


Bicycling is becoming an increasingly more popular fonn 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 current trend is to construct bicycles which are stronger as well as lighter than prior bicycles.
According]^, every part of a bicycle is constantly being redesigned to minimize weight and maximiw strength. One part of the bicycle which has been redesigned to be lighter and stronger is the bicycle crank arm. Each bicycle has a pair of bicycle CTank arms which are coupled to the bicycle crank spindle. The crank arms octend outwardly from the crank spindle in opposite directions and have pedals attached to their &ee ends for supporting the rider's feet. Rotation of the pedals by the rider causes one or more front sprockets to rotate wluch in turn moves the bicycle chun to rotate one or more rear sprockets, and thus, rotate the rear wheel of the bicycle. In certain crank arm designs, the front sprocket or sprockets are coupled directly to the crank arm by fastening fingers. The fastening fingers are coupled to the hub portion of the crank arm, and extend radially outwardly from the hub portion of the crank arm.
An example of such a crank arm is sold by Shimano, Inc. under its Dura-Ace line of professional components. One drawback of this crank arm is that the &stening fingers which are adjacent the crank portion are stiffer than the remaining &stening fingers. Bspedally for the competitive or serious rider, the connection between tiie &stening fingers of the crank arm and the front sprocket or sprockets should be uniform. Another drawback to the crank arm sold by Shimano, Inc. under its Dura-Ace line of professional con^}onents is that it is difiScult to property finish the crank arm ^ce the festening fingers which are adjacent the crank portion have ribs that interfere with the welding and polishing of a weld located therdjetween.
In view of the above, there exists a need for a bicycle crank arm having &stening fingers with substantially the same stif&ess for supporting and coupling a sprocket thereto. Also there exists a need for a bicycle crank arm having &stening fingers which do not interfere with the manufacturing and finishing of the crank arm.

This invention addresses these needs in the art as well as other needs in the art which will become apparent to those skilled in the art from this disclosure.
Summary -of^a-Inven^f^n
One object of the present invention is to provide a bicycle crank aim having fastening fingers with substantially the same stiffiiess at their free ends for supporting and coupling one or more sprockets thereto.
Another object of the present invention is to provide a sprocket supporting crank arm which is relatively easy and inexpensive to manufacture.
Still another object of the present invention is to provide a bicycle crank arm which is light weight and strong.
The foregoing objects can basically be attained by providing a bicycle crank arm. having a hi^ portioti adapted to be coupled to a crank spindle of a bicyde, a crank portion having an inner end coupled to the hub portion and an outer end adapted to be coupled to a bicyde pedal; and st least three fastening fingers extending radially outwardly fi-om the hub portion to a free end for mounting a bicycle sprocket thereto. The iimer end of the crank portion interconnects a pair of the &stening fingers. The &5temng fingers have substantiaUy the same stiffness at the free ends of the fastening fingers.
In a preferred form of the present invention, the crank portion, hub portion and &stening fingers are all formed as a one-piece, unitary member. Preferably, the crank portion has a recess with a lid member attached thereto.
ID the preened embodiment of the present invention, the hub portion has five fetrfwiing fingers with mounting holes formed at their fi'ee ends for coupling a sprocket thereto via conventional &steaer5.
In other embodiments of the present invention, the fiistening fingers can support two or more sprockets.

Accordingly the present invention provides a bicycle crank ann comprising: a bicycle hub portion; a crank portion having an inner end coupled to said hub portion and an outer free end; and at least three fastening fingers extending radially outwardly from said hub portion to free ends for forming bicycle sprocket mounting portions, said inner end of said crank portion interconnecting a pair of said fastening fingers, each of said fastening fingers having a front surface and a stiffness in a direction nomial to respective said front surface at respective said free ends, the difference between each of said stiffnesses' being less than thirty percent of each of said stiffnesses' individually, each of said fastening fingers not adjacent to said crank portion having a longitudinally extending rib.
Other objects, advantages and salient features 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 preferred embodiments of the present invention.

EL-i-Xn Uii*l!M*JM •JlrM'UliXuiiik
Referring now to the attached drawings which form part of this original disclosure:
Figure 1 is a side elevational view of a conventional bicycle using a crank arm in accordance with the present invention;
Figure 2 is a partial end elevational view of the crank arm illustrated in Figure 1 coupled to a crank spindle and with certain parts shown in cross-section for the purposes of illustration;
Figure 3 is a front side elevational view of a crank arm in accordance with the present invention with a sprocket fixedly coupled to the crank arm to fonn a crank set;
Figure 4 is a front side elevational view of the crank arm illustrated in Hgure 2 with certain parts removed for purposes of illustration;
Figure 5 is a rear side elevational view of the o^mk ann illustrated in Figures 2 and 3 with certain parts removed for purposes of illustration;
Figure 6 is an end elevational view of the crank arm illustrated in Figures 2-4 with certain parts removed for purposes of illustration;
Figure 7 is a longitudinal cross-sectional view of the crank arm iUustrated in Figures 2-S taken along section line 6-6 of Figure 5;
Figure 8 is a transverse cross-sectional view of one of the fastening fingers of . the crank aim illustrated in Figures 3-5 taken along section line 8-8 of Hgure 5;
Figure 9 is a transverse cross-sectional view of one of the &stening fingers positioned adjacent the crank portion of the crank arm illustrated in Figures 3-S, taken along section line 9-9 of Figure 5;
Figure 10 is a transverse cross-sectional view of the oank aim illustrated m Figures 3-5, taken along section line 10-10 of Figure 5;
Figure U is an outer side elevational view of the hd member for the crank arm illustrated in Figures 3-7;
Figure 12 is an end elevational view of the lid member illustrated in Figure 11 for the crank arm illustrated in Figures 3-7;
Figure 13 is a front side elevational view of a crank arm in accordance with a second embodiment of the present invention with a pair of sprockets attached thereto;

Figure 14 is a front side elevational view of a crank arm in accordance with a third embodiment of tiie present invention; and
figure 15 is a fi"ont side elevational view of a crank arm in accordance with a fourth embodiment of the present invention.
Betafed^esertpaoa of the Prefentd Cmbudimcirts
Referring initially to Figures 1 and 2, a conventional bicyde 10 is illustrated having a crank assembly 12 in accordance with the present inventioa Bicycles and their various con^)onents are well-known in the prior art, and thus, bicycle 10 and its various components will not be discussed or illustrated in detail herein, except for the components which relate to the present inventioa In other words, only crank assanfaly 12 will be discussed and illustrated in detail herein.
Basically, crank assembly 12 includes a right crank arm 14, a left crask ann 16, a crank spindle 18, one or more sprockets 20 and a p^ of pedals 22. Left crank arm 16, crank spindle 18, one or more sprockets 20 and a pair of pedals 22 are preferably conventional components which are well known in the art. Thus, these components will not be discussed in detail herein. By way of example, these components can be similar to the corresponding components of Shimano's Dura-Ace Une.
Rrferring now to Figures 3-5, right crank arm 14 includes a hub portion 30, a crank portion 32, five festening fingers 34 and a hd member 36. Preferably, hub portion 30, crank portion 32 and festening fingers 34 are all integrally formed as a one-piece, unitary member utilizing conventional manufecturing techniques such as stamping or casting. Preferably, crank arm 14 is constructed of a light weight metallic material suc^ as titanium, an alunumuu alloy or stainless steel.
lid member 36, on the other hand, is preferably fixedly coupled to crank portion 32 such that it becomes an integral part of crank portion 32. Pre&rably, lid member 36 is secured to crank portion 32 by arc welding utilizing aigon gas. Of course, lid member 36 can be joined to crank portion 32 by an adhesive instead of by welding. Examples of adhesives which can be utilized include epoxy resins and cyanoacrylates. Caulking and other types of adhesives may also be used.

Hub portion 30 has a center bore 40 for non-rotatably receiving crank spindle 18 therein. Preferably, bore 40 has a non-circular cross-section which mates with the end of crank spindle 18. For example, bore 40 can be splined to mate with splines of crank spindle 18. Of course, it will be apparent to those skilled in the art from tins disclosure that other known shapes can be utilized. Hub portion 30 is fixedly coupled to crank spindle 18 via a conventiona! crank bolt 42 in a substantiaUy couvrational manner. Accordii^y, rotation of hub portion 30 causes crank spindle 18 to rotate therewith. The front surface of hub portion 30 is preferably smooth and blends into crank portion 32 and &stening fingers 34. The rear surface of hub portion 30 has an annular flange 44 surrounding bore 40.
Crank portion 32 has an inner end 50 integrally formed with hub portion 30 and a £"66 outer end 52 with a mounting hole 54 formed therein for attachmg one of the pedals 22 thereto. Preferably, mounting hole 54 is threaded to fixedly couple the spindle of one of the pedals 22 thereto in a conventional manner. Crank portion 32 preferably also has a longitudinally extending recess 56 which extends between inner end 50 and outer end 52 adjacent mounting hole 54, This recess 56 is covered by lid member 36 to form a hollow crank portion 32. By providing recess 56 in CTank portion32, the wd^t of crank arm 14 can be minimized. Of course, recess 56 and tid member 36 can be dinunated, if needed or desired.
Recess 56 is substantiaUy keel-shaped, with the bottom portion of recess 56 being virtually parallel to the fi'ont surface of crank portion 32 along its middle section. The upper periphery of recess 56 is provided with an annular step or ledge 58 for receiving and supporting lid member 36 therein. In particular, Ud member 36 fits into recess 56 and sits on annular ledge 58, and is then welded thereto. Of course, ai^ build-up from welding can be ground 06" to produce a finished sur&ce with an attractive appearance. Once lid member 36 is welded to crank portion 32, recess 56 becomes completely enclosed to form a hollow crank arm. Preferably, lid member 36 forms a substantially flat, rear surfece of crank portion 32.
Fastening fingers 34 extend radially outwardly from hub portion 30 and has a free end 60. Free end 60 of each fastening finger 34 has a mounting hole 62 for securing at least one sprocket 20 thereto via a plurality of festeners 64. Prefer^Iy,

festeners 64 are conventional fasteners. For example, fasteners 64 can be ^hain wheel mounting bolts with ring nuts which are commonly used to couple the sprocket to the festening fingers of a crank arm, Fasteners 64 are preferably constructed of a light weight material such as an aluminum alloy or titanium. Of course, other types of festeners and /or materials can be utilized.
As seen in Figures 4 and 5, fastening fingers 34 are preferably equally spaced apart about hub portion 30, i.e., fastening fingers 34 are spaced 72° apart. Of course, while five &stemng fingers 34 are illustrated, It M11 be apparent to those skilled in the art fi'om this disclosure that fewer or more fastening fingers 34 could be utilized. For example, crank arm 14 could be constructed with three or four &5temng fingers which are equally spaced apart about the center of hub portion 30. In these variations, of course, it is desirable to have the fastening fingers with substantially the same stiffitess at th»T free ends as discussed below.
As seen in Figure 4, the fi^ont surfaces of fastening fingers 34 have a contoured section 66 and a substantially flat section 6S. Each contoured section 66 U curved along the length of ite festening fingers 34 between its flat section 68 and hub portion 30. At hub portion 30, contoured sections 66 blends smoothly into hub portion 30 and into crank portion 32.
As seen in Figures 2, 6 and 7, flat sections 68 of the front surfece are located al the fl'ee ends 60 of each of the &stening fingers 34. Flat sections 6S engage the rear surface of sprocket 20 for supporting sprocket 20 thereon. Preferably, the flat sections 68 are recessed from the respective contoured section 66 of the front surfece of the respective &stening finger 34 such that a smooth transition occurs between the contoured sections 66 of festening fingers 34 and the rear surfiice of sprocket 20.
As seen in Figures S and 8, the three fastening fingers 34 which are not adjacent to crank portion 32 each has a centrally located rib 74 and a pair of curved recesses 76. Ribs 74 extend radially outwardly from annular flange 44 to free ends 60, with one of the curved recesses 76 being located on each side of each of the ribs 74 to form a transverse cross-section as seen in Figure 8. Rib 74 adds additional strength to each of these festening fingers 34 to provide them with the desired stifQiess. The two fastening fingers 34 which are adjacent to crank portion 32 have widths, meaaired

between their front and rear sides, that are smaller than the widths of the remaining three festening fingers 34 as measured between their front and rear sides. In other words, each rib 74 extends outwardly from its base portion of its associated festening finger to form an inverted T-shape as seen in Figure S. The two fastening fingers 34 adjacent crank portion 32 are flatter than the remaining fastening fingers 34. Also the rear surfaces of the festening fingers 34 which are adjacent crank portion 32 are lower than the rear sur&ce of crank portion 32. This allows lid member 36 to be easily fastened and finished without interference from the adjacent fastening fingers 34 as mentioned below.
The remaimng two festening fingers 34 do not have such ribs which correspond to libs 74. In particular, if the fastening fingers 34 adjacent to the crank portion 32 were provided with ribs, than they would be stiflfer than the other three festemng fingers 34. This is due to the fact that the crank portion 32 provides additional rigidity and stiffiiess to the two adjacent fastening fingers 34. Therefore, the two festening fingers 34 adjacent to crank portion 32 have a different transverse cross-section than the other festening fingers 34 as seen in Figures 9 and 10. In particular, the two fastening fingers 34 adjacent crank portion 32 have web sections 78 interconnecting crank portion 32 with tiie two adjacent fasteiung fingers 34. Each of the two festeanng fingers 34 adjacent crank portion 32 also has a curved recess 80 ectendu^ radially outwardly from annular flange 44 to its free end 60.
Bad) fest^ung filler 34 of crank arm 14 has a sti£&ess in a direction normal to its flat section 68 at its fr%e end 60. The festening fingers 34 are ideally dedgoed such that eacii festening finger 34 has substantially the same stif&ess. However, it is acceptable if the difiEerence between the stiffiiess' of each pair of the festening fingers 34 is less than fifty percent of the individual stiffiiess' of each of the festening fingers 34. The difference between the stiffiiess' of each pah- of the festening fingers 34 is also acceptable if it is less than thirty percent of the individual stiffiiess' of each of the fastening fingers 34. However, if the stiffiiess' of the fastening fingers 34 are to differ at ail, it is preferred that the difference between the stiffiiess' of each pair of the festening fingers 34 be about or less than twenty percent of the individual stiffiiess of each of the festening fingers 34.

Referring now to Figures 11 and 12, lid member 36 is shaped to correspond to the periphery of recess 56 and has a flat outer surfece 84 and a flat inner sur&ce 86 with a peripheral flange 88. Preferably, flange 88 is angled downwardly to ragage step or ledge 58 of crank portion 32 such that an annular groove is formed for weldmg lid member 36 to crank portion 32 as mentioned above and as seen in Figure 7. The inner end 90 of Ud member 36 is ground down to remove the access weld material as well as to provide the desired finish as shown by the hatching Figure 5. Lid member 36 is preferably formed of the same material as crank portion 32, and formed by using conventional manu&cturing methods such as stampmg or casting.
Second Embodunent of Fipure 13
Referring now to Figure 13, a crank set 2U in accordance with a second embodiment of the present invention is illustrated. Crank set 211 has a rig^ crank arm 214 and a pair of sprockets 220. Basically, right crank aim 214 includes a hub portion 230, a crank portion 232, five festening fingers 234 and a Ud member (not shown). Preferably, hub portion 230, crank portion 232 and festening fingers 234 are all integrally formed as a one-piece, umtary member utili2dng conventional ipanu&cturing techniques such as stamping or casting. The Ud member, on the other hand, is preferably fixedly coupled to crank portion 232 such that it becomes an integral part of crank portion 232. Hub portion 230, crank portion 232 and fast«iii« fingers 234 are all constructed in the same manner as the first embodiment. Thus, this embocUmoit wiU not be discussed or iUustrated in detail.
BasicaUy, the only substantive diflference between the first and second embodiments are the number of sprockets attached thereto.
Third Emt>o(jigieBt of I^igurg 14
Referring now to Figure 14, a right crank arm 314 m accordance with a third embodiment of the present invention is iUustrated. BasicaUy, right crank ann 314 includes a hub portion 330, a crank portion 332, five fastening fingers 334 and a lid member (not shown). Preferably, hub portion 330, crank portion 332 and fiistening fingers 334 are aU integraUy formed as a one-piece, imitary member utilizing

conventional manufacturing techniques such as stamping or casti:^. The lid member, on the other hand, is preferably fixedly coupled to crank portion 332 such tha it becomes an integral part of crank portion 332, Hub portion 330, crank portion 332 and fastening fingers 334 are all constructed in the same manner as the first embodiment. Thus, this embodiment will not be discussed or illustrated in detail
Basically, the only substantive difference between the first and third embodiment is the shape of the two fastening fingers 334 which are adjacent to crank portion 332. Preferably, the two fastenii^ fingers 334 which are at^acent to crank portion 332 are narrower than fasteni:^ fillers 334 which are not adjacent to crank portion 332 as shown in F^^re 14.
Accordingly, the two festening fingers 334 which are adjacent to crank portion 332 are modified such that each of the five fasteoii^ fingers 334 have substantially the same the stifibess in a direction normal to their flat sections 368 at their free ends 360. However, it i& acc^table if the individual difference betweMi the stifl&iess' of each fastening fillers 334 is less than S0% of the individual sti&ess' of each of the fastening fillers 334. The diSer^ice between tlie stiffiiess' of each of fastening fingers 334 is also acc^toble if it is less than 30% of the individual stif&iess' of each of the fastttiing fingers 334. However, if the sdf&iess' of the fastenir^ fitters 334 are to differ at all, it is preferable that the difference between the stif&iess' of eaidi of fastening fingers 334 be ahoiaX or less than 20% of the individual sti&ess' of eadi of the fastening fingers 334.
It will be apparait to those skilled in the ait that the rear ade of fitstemng fingers 334 can be manufactured in the same manner as the rear ^de of fiisteoing fingers 34 of the first embodiment of the present invention. In other words, the fastenii^ fingers 334 vMch are adjacent crank portion 332 can be fi^e of ribs, while the remaining fastenii^ fingers 334 can have ribs. However, it will bfr i^ipareot to those skilled in the art that the rear sides of fastening fingers 334 adjacent to crank portion 332 could be manufactured with various modifications. For example, the rear ades of fastening fingws 334 adjacent to crank portion 332 could be manu&cturwi with ribs amilar to fastening fingers 334 which are not adjacail to crank portion 332, since the sfiffiiess of the fasteiung fingers adjacent crank portion 332 has been reduced

by changing its width, i.e., the two festening fingers 334 windi are adjacent to crank portion 332 are narrower than fastraing fingers 334 which are not adjacent to crank portion 332.
Fourth Embodiment of Figure 15
Referrii^ now to Figure 14, a right crank arm 414 in accordance wth the present invention is ilhistrated. Basically, right crank arm 414 includes a hub portion 430, a crank portion 432. five fastening fingers 434 and a hd member (not shown). Preferably, Imb portion 430, crank portion 432 and festening fingers 434; are all integrally fonned as a one-piece, unitary member utilizing conventional manu&cturing techniques such as stampmg or casting. The lid member, on the other hand, is preferably fixedly coupled to crank portion 432 such that it becomes an integral part of crank portion 432. Hub portion 430, crank portion 432 and &stening fingers 434 are all constructed in the same manner as the first embodiment. Thus, this embodinunt nil! not be discussed or illustrated in detail.
Ba^cally, the only substantive difference between the first and fisurth embodiments is the shape of the outer sprocket mountmg portions 468 at the fi^ee ends 460 of festening fingers 434 adjacent crank portion 432 as seen in Figure 15. Preferably, the flat outer free ends 460 of festenmg fingers 434 which are adjacent crank portion 432 will be in the shape of a trapezoid. This arrangement results m the connections between festening fingers 434 and the assodate sprocket to have substantially the same stiffiiess. In other words, by making the fi^e ends 460 of the two fastening fingers 434 adjacent crank portion 432 more fleable, the stifBiess of the fi-ee ends 460 are substantially the same.
Accordingly, the two fastening fingers 434 which are adjacent to crank portion 432 are modified such that each of the five festenmg fingers 434 have substantially the same the stiffiiess in a direction nonnal to their flat sections 468 at their fi^ee ends 460. However, it is acceptable if the mdi\ddual difference between the stif&iess' of each festening fingers 434 is less than 50% of the individual stiffiiess' of each of the fastening fingers 434. The difference between the stiffiiess' of each of fastening fingers 434 is also acceptable if h is less than 30% of the individual stiffiiess' of each of the

festening fingers 434. However, if the sti£&iess' of the fastening fingers 434 are to differ at all, it is preferable that the difference between the stiffiiess' of each of festening fingers 434 be about or less than 20% of the individual stiffiiess' of each of the festening fingers 434.
It will be apparent to those skilled in the art that the outer fi-ee ends 460 of festening fingers 434 adjacent crank portion 432 could be foraied into other shapes as desired or needed to reduce the stiffiiess of these festening fillers. For example, outer fi-ee ends 460 of festening fingers 434 adjacent crank portion 432 could be circular.
While only fourth embodiments of the present invention have been described and illustrated, it will be apparent to those skilled in the art once given tlu5 disclosure ^t various modificatioas, changes, improvements and variations may be made without departing fi^om the spirit or scope of this invention as defined in the following claims.
It will be apparent to those skilled in the art that the rear side of festening fingers 434 can be manufectured in the same manner as the rear side of festmi^ fingers 34 of the first embodiment of the present invention. In other words, the festening fingers 434 which are adjacent crank portion 432 can be free of ribs, while the remaining festening fingers 434 can have ribs. However, it will be apparent to those skilled in the art tiiat the rear sides of fastening fingers 434 adjacent to crank portion 432 could be manufectured with various modifications. For scample, the rear sides of festening fingers 434 adjacent to crank portion 432 could be manufectured with ribs similar to festening fingers 434 which are not adjacent to crank portion 432, Mnce the stiffiiess of the fastening fingers adjacent crank portion 432 has been reduced by char^i^ the shapes of the sprocket mounting portions 468, i.e.» the two festening fingers 434 which are adjacent to crank portion 432 have more flexible the sprocket mounting portions 468.


WE CLAIM:
1. A bicycle crank arm comprising: a bicycle hub portion; a crank portion having an inner end coupled to said hub portion and an outer free end; and at least three fastening fingers extending radially outwardly from said hub portion to free ends for forming bicycle sprocket mounting portions, said inner end of said crank portion interconnecting a pair of said fastening fingers, each of said fastening fingers having a front surface and a stiffness in a direction normal to respective said front surface at respective said free ends, the difference between each of said stiffnesses' being less than thirty percent of each of said stiffnesses' individually, each of said fastening fingers not adjacent to said crank portion having a longitudinally extending rib,
2. The bicycle crank arm as claimed in claim 1, wherein said crank portion has a longitudinally extending recess betw-'een said inner end and said outer end.
3. The bicycle crank arm as claimed in claim 2, wherein said recess is covered by a lid member fixedly secured over said recess.
4. The bicycle crank arm as claimed in claim 1, wherein at least a total of five fastening fingers extend radially outwardly from said hub portion.
5. The bicycle crank arm as claimed in claim 1, wherein said rib of each of said fastening fingers not adjacent to said crank portion is centrally located.
6. The bicycle crank arm as claimed in claim 5, wherein each of said fastening fingers not adjacent to said crank portion has a longitudinally extending groove on each side of each of said ribs.

7. The bicycle crank arm as claimed in claim 6, wherein each of said fastening fingers interconnected with said crank portion has a longitudinally extending groove.
8. The bicycle crank arm as claimed in claim 7, wherein said grooves are offset from the longitudinal axis of said fastening fingers which are interconnected with said crank portion.
9. The bicycle crank arm as claimed in claim 1, wherein said difference between each of said stiffnesses' is less than twenty percent of each of said stiffnesses' individually.
10. The bicycle crank arm as claimed in claim 1, wherein said hub, said crank portion, and said fastening fingers are all integrally formed as a one-piece, unitary member.
11. A bicycle crank arm comprising: a bicycle hub portion; a crank portion having an inner end coupled to said hub portion and an outer free end; and at least a total of five fastening fingers extending radially outwardly from said hub portion to free ends for forming bicycle sprocket mounting portions, said inner end of said crank portion interconnecting a pair of said fastening fingers, each of said fastening fingers having a front surface and a stiffness in a direction normal to respective said front surface at respective said free ends, the difference between each of said stiffnesses' being less than thirty percent of each of said stiffnesses' individually, each of said fastening fingers not adjacent to said crank portion having a longitudinally extending rib; and at least one sprocket couple to said free ends of said fastening fingers.
12. A bicycle crank arm comprising: a bicycle hub portion; a crank portion having an inner end coupled to said hub portion and an outer free end; and at least three fastening fingers extending radially outwardly from said hub portion to free ends for

forming bicycle sprocket mounting portions, said inner end of said crank portion interconnecting a pair of said fastening fingers, each of said fastening fingers having a longitudinal axis extending radially outwardly from said hubs, each of said pair of fastening fmgers interconnected with said crank portion having a longitudinally extending groove and a web section that extends from said respective groove to said crank portion, said fastening fingers not adjacent to said crank portion having a longitudinal extending rib.
13. The bicycle crank arm as claimed in claim 12, wherein said rib of each of said fastening fmgers not adjacent to said crank portion is centrally located.
14. The bicycle crank arm as claimed in claim 13, wherein each of said fastening fingers not adjacent to said crank portion has a longitudinally extending groove on each side of each of said ribs.
15. The bicycle crank arm as claimed in claim 14, wherein said grooves of said fastening fingers interconnected with said crank portion are offset from the longitudinal axis of said fastening fmgers which are interconnected with said crank portion.
16. The bicycle crank arm as claimed in claim 12, wherein said crank portion has a longitudinally extending recess between said inner end and said outer end.
17. The bicycle crank arm as claimed in claim 16, wherein said recess is covered by a lid member fixedly secured over said recess,
18. The bicycle crank arm as claimed in claim 12, wherein at least a total of five
fastening fmgers extend radially outwardly fi-om said hub portion.

Documents:

2927-mas-1997 abstract.pdf

2927-mas-1997 claims-duplicate.pdf

2927-mas-1997 claims.pdf

2927-mas-1997 correspondence-others.pdf

2927-mas-1997 correspondence-po.pdf

2927-mas-1997 description (complete)-duplicate.pdf

2927-mas-1997 description (complete).pdf

2927-mas-1997 drawings-duplicate.pdf

2927-mas-1997 drawings.pdf

2927-mas-1997 form-19.pdf

2927-mas-1997 form-2.pdf

2927-mas-1997 form-26.pdf

2927-mas-1997 form-4.pdf

2927-mas-1997 form-6.pdf

2927-mas-1997 others.pdf

2927-mas-1997 petition.pdf


Patent Number 198676
Indian Patent Application Number 2927/MAS/1997
PG Journal Number 30/2009
Publication Date 24-Jul-2009
Grant Date
Date of Filing 17-Dec-1997
Name of Patentee SHIMANO INC,
Applicant Address 77 OIMATSU-CYO 3-CYO, SAKAI-SHI, OSAKA 590-77
Inventors:
# Inventor's Name Inventor's Address
1 MASAHIRO YAMANAKA 831-6, NAKASYO, IZUMISANO-SHI, OSAKA,
PCT International Classification Number B62M3/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 08/770, 501 1996-12-20 U.S.A.