Crank assembly particularly suited for bicycles

Abstract

A bicycle crank assembly is provided having a sprocket flange and a pedal crank arm, the sprocket flange being coaxially affixed to a bicycle crank shaft, the first end of the pedal crank arm being coaxially mounted about a laterally projecting generally cylindrical shaft member of the sprocket flange, a pedal bolt being affixed proximate a distal end of the pedal crank arm, and the pedal crank arm being affixed proximate the perimeter of the sprocket flange generally opposite the pedal bolt with a 145 degree offset about the axis of rotation of the bicycle crank shaft to increase the distance from the drive bolt to the pedal and to increase the leverage and power imparted to the bicycle crank assembly. A sprocket is coaxially affixed to the sprocket flange. A second pedal-powered crank assembly is coaxially affixed to the opposite end of the bicycle crank shaft, with a 180 degree offset about the axis of rotation of the bicycle crank shaft from the first pedal-powered crank assembly to provide continuous, uninterrupted torque to the bicycle crank shaft through a 360-degree rotation of the pedal-powered crank assembly.

Claims

1. A first pedal-powered crank assembly, particularly suited for use in combination with a bicycle crank shaft, said pedal-powered crank assembly comprising: a first sprocket flange having a first sprocket flange front side and a first sprocket flange back side; means for coaxially affixing said first sprocket flange to the first end of a crank shaft; a first pedal crank arm having a first pedal crank arm first end and a first pedal crank arm distal end; means for coaxially affixing said first pedal crank arm first end about said first sprocket flange; a first pedal bolt; means for affixing said first pedal bolt proximate said first pedal crank arm distal end of said first pedal crank arm; and means for affixing said first pedal crank arm proximate the perimeter of said first sprocket flange generally opposite said first pedal bolt with an offset about the axis of rotation of the bicycle crank shaft.

2. The first pedal-powered crank assembly of claim 1, wherein the offset measures approximately 145 degrees.

3. The first pedal-powered crank assembly of claim 1, further comprising a sprocket and means for coaxially affixing said sprocket to said first sprocket flange.

4. The first pedal-powered crank assembly of claim 1, wherein said means for coaxially affixing said first sprocket flange to the first end of a crank shaft comprises said first sprocket flange defining a cavity on said back side dimensioned for cooperative engagement of and coaxial mounting on the end of the crank shaft.

5. The first pedal-powered crank assembly of claim 1, wherein said means for coaxially affixing said first end of said first pedal crank arm about said first sprocket flange comprises said front side of said first sprocket flange defining a first laterally projecting generally cylindrical shaft member dimensioned for cooperative engagement with said first pedal crank arm.

6. The first pedal-powered crank assembly of claim 1, wherein said first pedal crank arm is generally concave-shaped.

7. A bicycle comprising the first pedal-powered crank assembly of claim 1 further comprising a second pedal-powered crank assembly constructed according to the principles of the first pedal-powered crank assembly coaxially affixed to the opposite end of the bicycle crank shaft, with the first pedal-powered crank assembly and second pedal-powered crank assembly 180 degrees opposed to each other to provide continuous, uninterrupted torque to the bicycle crank shaft through a 360-degree rotation of the first bicycle crank assembly and second pedal-powered crank assembly.

8. The first pedal-powered crank assembly of claim 7, wherein the offset measures approximately 145 degrees.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a perspective view of the pedal-powered crank assembly of a preferred embodiment of the invention employed with a conventional bicycle crank shaft and conventional pedal bolt.

[0015] FIG. 2 is a front elevational view of a pedal-powered crank assembly of a preferred embodiment of the invention.

[0016] FIG. 3 is a rear elevational view of a pedal-powered crank assembly of a preferred embodiment of the invention.

[0017] FIG. 4 is a left side elevational view of a pedal-powered crank assembly of a preferred embodiment of the invention.

[0018] FIG. 5 is a right side elevational view of a pedal-powered crank assembly of a preferred embodiment of the invention.

[0019] FIG. 6 is a front elevational view of a sprocket flange of a preferred embodiment of the invention.

[0020] FIG. 7 is a rear elevational view of a sprocket flange of a preferred embodiment of the invention.

[0021] FIG. 8 is a left side elevational view of a sprocket flange of a preferred embodiment of the invention.

[0022] FIG. 9 is a right side elevational view of a sprocket flange of a preferred embodiment of the invention.

[0023] FIG. 10 is a front elevational view of a pedal crank arm of a preferred embodiment of the invention.

[0024] FIG. 11 is a rear elevational view of a pedal crank arm of a preferred embodiment of the invention.

[0025] FIG. 12 is a left side elevational view of a pedal crank arm of a preferred embodiment of the invention.

[0026] FIG. 13 is a right side elevational view of a pedal crank arm of a preferred embodiment of the invention.

[0027] FIG. 14 is a right side elevational view of a second step washer of a preferred embodiment of the invention.

[0028] FIG. 15 is a front elevational view of a second step washer of a preferred embodiment of the invention.

[0029] FIG. 16 is a rear elevational view of a second step washer of a preferred embodiment of the invention.

[0030] FIG. 17 is a right side elevational view of a first threaded button head drive bolt of a preferred embodiment of the invention.

[0031] FIG. 18 is a front elevational view of a first threaded button head drive bolt of a preferred embodiment of the invention.

[0032] FIG. 19 is a rear elevational view of a first threaded button head drive bolt of a preferred embodiment of the invention.

[0033] FIG. 20 is a right side elevational view of a first step washer of a preferred embodiment of the invention.

[0034] FIG. 21 is a front elevational view of a first step washer of a preferred embodiment of the invention.

[0035] FIG. 22 is a rear elevational view of a first step washer of a preferred embodiment of the invention.

[0036] FIG. 23 is a right side elevational view of a second threaded button head drive bolt of a preferred embodiment of the invention.

[0037] FIG. 24 is a front elevational view of a second threaded button head drive bolt of a preferred embodiment of the invention.

[0038] FIG. 25 is a rear elevational view of a second threaded button head drive bolt of a preferred embodiment of the invention.

[0039] FIG. 26 is a rear elevational view of a sprocket flange of a second pedal-powered crank assembly of the preferred embodiment of the invention.

[0040] FIG. 27 is a rear elevational view of a sprocket flange of a second pedal-powered crank assembly of the preferred embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0041] While this present invention is susceptible of embodiments in many different forms, there are shown in the drawings and will be described in detail herein, a preferred embodiment, with like parts designated by like reference numerals and with the understanding that the present disclosure is to be considered as an exemplification of the principles of the present invention, and is not intended to limit the claims to the illustrated preferred embodiment.

[0042] FIG. 1 illustrates, in a preferred embodiment, a conventional bicycle crank shaft 10 mounted in a conventional bicycle hub 11 and defining a generally axially threaded chamber (not shown) extending at least partially therethrough, a first conventional pedal bolt 12 having one or more threaded ends (not shown), a pedal-powered crank assembly 20 having a first sprocket flange 30 and a first pedal crank arm 40, the conventional sprocket 13 coaxially affixed to the first sprocket flange 30, and the first conventional pedal bolt 12 affixed to the first pedal crank arm 40.

[0043] FIGS. 2-5 illustrate, in a preferred embodiment, the pedal-powered crank assembly 20.

[0044] FIGS. 6-9 illustrate, in a preferred embodiment, the first sprocket flange 30. The generally disc-shaped first sprocket flange 30 has a front side 31, a back side 32, and defines a cavity 33 on the back side 32 dimensioned for cooperative engagement of and coaxial mounting the first sprocket flange 30 on the end of the conventional bicycle crank shaft 10. The first sprocket flange 30 defines a generally cylindrical opening 34 extending axially therethrough for receiving the conventional threaded bicycle crank bolt 35. The front side 31 of the first sprocket flange 30 defines a first laterally projecting generally cylindrical shaft member 50 dimensioned for cooperative engagement with the first pedal crank arm 40. The first sprocket flange 30 defines a first generally cylindrical slot 37 extending therethrough and disposed proximate the perimeter of the first sprocket flange 30 for receiving a first step washer 38 therein, as shown in in FIGS. 6 and 7, although it should also be readily understood by those skilled in the art that a threaded cylinder could be integrally constructed with the first sprocket flange 30 in place of a first generally cylindrical slot 37 and a first step washer 38. The first sprocket flange 30 defines a plurality of radially disposed generally cylindrical first apertures 39 proximate the perimeter of the first sprocket flange 30. In the preferred embodiment, the first sprocket flange 30 is constructed of an aluminum alloy, although it should also be readily understood by those skilled in the art that any suitable material of constriction should suffice. In use, the conventional sprocket 13 is coaxially affixed to the first sprocket flange 30 using a plurality of bolts 52 (shown in FIG. 1) disposed in the generally cylindrical first apertures 39 proximate the perimeter of the first sprocket flange 30, although it should be readily understood by those skilled in the art that other attachments means, such as welding may suffice. It should also be readily understood by those skilled in the art that the conventional sprocket 13 may be integrally formed with the first sprocket flange 30.

[0045] FIGS. 10-13 illustrate, in a preferred embodiment, the first pedal crank arm 40. The first pedal crank arm 40 has a front side 41, a back side 42, a first end 43, and a distal end 44. The first pedal crank arm 40 defines a first generally cylindrical hollow 48 in the first end 43 for coaxially mounting the first pedal crank arm 40 on the first laterally projecting generally cylindrical shaft member 50 of the first sprocket flange 30 and using a first conventional threaded crank bolt 35 for fastening the first sprocket flange 30 and the first pedal crank arm 40 to the threaded chamber on the end of the bicycle crank shaft 10, as shown in FIG. 1.

[0046] The first generally cylindrical hollow 48 of the first pedal crank arm 40 is preferably dimensioned to receive a second step washer 60, as illustrated in FIGS. 1 and 14-16.

[0047] The first pedal crank arm 40 defines a second generally cylindrical hollow 45 extending therethrough. The second generally cylindrical hollow 44 and the first generally cylindrical slot 37 are aligned and a second threaded bolt 36 is received through the second generally cylindrical hollow 45 and threaded into the first step washer 38 to fasten the first pedal crank arm 40 to the first sprocket flange 30.

[0048] The second threaded bolt 36 is preferably a threaded button head drive bolt, as illustrated in FIGS. 17-19.

[0049] The first pedal crank arm 40 defines a third generally cylindrical hollow 46 which is disposed proximate a distal end 44 of the first pedal crank arm 40, generally opposite the second threaded bolt 36 with a 145 degree offset about the axis of rotation of the bicycle crank shaft 10 to optimize the leverage and power imparted to the pedal-powered crank assembly 20. In the preferred embodiment, the first pedal crank arm 40 is generally concave-shaped from the distal end 44 to the second generally cylindrical hollow 45, although it should also be readily understood by those skilled in the art that other shapes may suffice. In the preferred embodiment, the first pedal crank arm 40 is constructed of an aluminum alloy, although it should also be readily understood by those skilled in the art that any suitable material of constriction should suffice.

[0050] In the preferred embodiment, a second pedal-powered crank assembly 120 constructed according to the principles of the first pedal-powered crank assembly 20 is coaxially affixed to the opposite end of the bicycle crank shaft 10, with the first pedal-powered crank assembly 20 and second pedal-powered crank assembly 120 disposed 180 degrees opposed to each other to provide continuous, uninterrupted torque to the bicycle crank shaft 10 through a 360-degree rotation of the first bicycle crank assembly 20 and second pedal-powered crank assembly 120. It should be readily understood by those skilled in the art that a second conventional pedal bolt should be employed, but a second conventional sprocket is not necessary.

[0051] FIGS. 26-27 illustrate, in a preferred embodiment, the sprocket flange 30 of the first pedal-powered crank assembly 20 and the sprocket flange of the second pedal-powered crank assembly 120 of the preferred embodiment of the invention, showing the cavity 33 on the back side 32 of each sprocket flange 30 dimensioned and disposed for cooperative engagement of and coaxial mounting on the end of the conventional bicycle crank shaft 10 in offset fashion.

[0052] Hence, while the invention has been described in connection with a preferred embodiment and alternative embodiments, it will be understood that it is not intended that the invention be limited to those embodiments. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as disclosed.

[0053] As to the manner of usage and operation of the instant invention, same should be apparent from the above disclosure, and accordingly no further discussion relevant to the manner of usage and operation of the instant invention shall be provided.

[0054] With respect to the above description then, it is to be realized that the optimum proportions for the elements of the invention, and variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships described in the specification are intended to be encompassed by the present invention.

[0055] Therefore, the foregoing is considered illustrative of only the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact method, construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.