TWI876289B - Bicycle chainring, bicycle crankset and bicycle drivetrain - Google Patents

Abstract

A solitary chainring of a bicycle front crankset for engaging a drive chain, including a plurality of teeth formed about a periphery of the chainring, the plurality of teeth consisting of an even number. The plurality of teeth includes a first group of teeth and a second group of teeth arranged alternatingly between the first group of teeth. The first group of teeth and the second group of teeth are equal in number. Each of the first and second group of teeth include an outboard side and an inboard side opposite the outboard side and each tooth of the first group of teeth includes at least a first protrusion on the outboard side thereof and each tooth of the second group of teeth are free of the first protrusions on the outboard side and the inboard side.

Description

Bicycle chain rings, bicycle crank gears and bicycle transmission systems

The present invention relates to a chain ring, and more particularly, to a separate chain ring that can be used with a conventional chain in a bicycle drive system including a bicycle crank.

Bicycles and other chain-driven vehicles typically use one or more chain rings and a set of sprockets mounted on the rear hub that are connected to a chain. Various mechanisms are used to maintain the chain and sprockets on the chain rings. These mechanisms include chain guards, zippers, derailleurs, and shifter assemblies.

When riding a vehicle with a chain-driven drive system, the arrangement of the chain and chain ring joints is extremely important to the safety and efficient propulsion of the bicycle. It is difficult for the chain to remain connected to the chain rings, especially on toothed bicycles where the chain tension may undergo drastic changes and strong chain movement, especially when riding over rough terrain.

Furthermore, in any bicycle, when the crank is in a position where it is subject to high loads from the rider, the chain ring has the potential to contact the bicycle frame's chain stays, causing elastic deformation of the bicycle frame and crank gears. This could result in damage to the frame and chain ring and cause other problems.

The present invention provides an enhanced drive chain arrangement, particularly for use with a bicycle, that enables it to be successfully and reliably ridden over rough and challenging terrain.

In one aspect, the present invention provides a single chain ring for a front crankset of a bicycle, for connecting a transmission chain. The single chain ring, where single means only one, includes a plurality of teeth formed around the chain ring, the number of the plurality of teeth being an even number. The plurality of teeth includes a first set of teeth and a second set of teeth alternately arranged between the first set of teeth. The first set of teeth and the second set of teeth have the same number. Each of the teeth of the first set of teeth and the second set of teeth includes an outer plate side and an inner plate side opposite to the outer plate side. Each of the first set of teeth includes at least one first protrusion on its outer plate side, while each of the second set of teeth has no protrusion.

The present invention also provides a separate chain ring of a front crank gear of a bicycle, which is used to connect a transmission chain, the transmission chain includes interlaced inner and outer links, the chain ring includes a number of teeth formed around the chain ring, and the number of the number of teeth is even. The number of teeth includes a first group of teeth and a second group of teeth staggered between the first group of teeth. The number of the first group of teeth is the same as that of the second group of teeth. Each of the teeth of the first group of teeth and the second group of teeth includes an outer plate side and an inner plate side opposite to the outer plate side. The outer plate side and the inner plate side of each of the second set of teeth respectively define a recess formed on the chain ring along each of the second set of teeth.

The present invention also contemplates a bicycle crank gear plate, comprising a bicycle crank arm and a separate chain ring attached to the bicycle crank arm and connectable to a transmission chain. The separate chain ring comprises a plurality of teeth formed around the chain ring, the number of the plurality of teeth being an even number, the plurality of teeth comprising a first set of teeth and a second set of teeth alternately arranged between the first set of teeth. The first set of teeth and the second set of teeth have the same number. Each of the teeth of the first set of teeth and the second set of teeth comprises an outer plate side and an inner plate side opposite to the outer plate side. Each of the first set of teeth includes at least one first protrusion on its outer plate side, while each of the second set of teeth does not have a first protrusion on its outer plate side and inner plate side.

These and other features and advantages of the present invention will be more fully understood from the following description of one or more embodiments of the present invention, together with the accompanying drawings.

The preferred embodiments of the present invention will be described with reference to the drawings. It will be understood that the drawings and descriptions mentioned herein are for illustration only and are not intended to limit the present invention, which is defined by the scope of the attached patent application and any and all equivalents thereof. For example, the terms "first" and "second" or "left" and "right" are used for ease of understanding and are not intended to be limiting.

Referring to the first and second figures of the drawings, reference numeral 10 generally refers to a roller drive chain of a conventional bicycle or any similar chain drive device. The drive chain 10 generally includes outer links 12 and inner links 14 pivotally mounted on and connected to the outer links by pins 16 and 18. The outer links 12 and the inner links 14 are interlaced and arranged in a staggered manner.

The outer links 12 have a pair of outer plates 20 and the inner links have a pair of inner plates 22. Generally, the rollers 24 are disposed about the pins 16, 18. The plates 20, 22 have holes 30 at the ends 32. The pins 16, 18 generally pass through and protrude out of the holes 30, but it is generally considered preferable that they do not protrude at all. The pins 16, 18 are externally riveted at their ends 34, 36 when the roller chain 10 is assembled. Although the pins 16 can be formed of round rods, the pins 18 can be formed of tubular rods, as in the roller chain 10 of FIG. 2. A narrow middle portion 38 that helps determine the positioning of the roller chain 10 extends between the two rounded ends 32 of each outer link plate 20 and inner link plate 22.

As shown in FIG. 1 , and viewed from the top (or bottom) of the chain, the interlacing of the outer links 12 and the inner links 14 creates corresponding interlaced outer chain spaces 40 and inner chain spaces 42. The outer chain spaces 40 are generally openings defined by the outer chain plates 20 and the rollers 24. The inner chain spaces 42 are generally openings defined by the inner chain plates 22 and the rollers 24.

The inner chain spaces 42 are generally rectangular, and the long axis of the rectangle is aligned with the long axis (A) of the chain 10 (as shown in FIG. 1 ). The axial length of the inner chain spaces 42 is determined by the distance between the rollers 24, and the distance between the inner chain plates 22 determines the lateral spacing of the inner chain spaces.

As shown in FIG. 1 , the outer chain spaces 40 are generally in the shape of a “cross” or other characters such as a “plus sign”. The axial length of the outer chain spaces 40 is determined by the distance between the rollers 24, and the distance between the outer chain plates 20 determines the lateral spacing of the outer chain spaces.

It can be seen that the lateral spacing between the outer link plates 20 is greater than the spacing between the inner link plates 22. Thus, since the lateral width of the rollers 24 determines the spacing of the inner link plates 22, the rollers 24 will dominate the lateral spacing D1 of the inner link spaces 42. Similarly, since the outer link plates 20 are positioned on the pins 16 (or 18) on the outer plate side of the inner link plates 22, the lateral spacing D2 of the outer link spaces 40 will be dominated by the sum of the lateral width of the rollers 24 and the thickness of the two inner link plates.

As shown in FIG. 3 , a sprocket 50 according to the present invention is used with a conventional chain 10. Sprockets generally have a greater number of teeth than cassettes, for example, about 20 or more teeth. A crank or crank arm 48 is attached to the sprocket 50 at a specific location and in a known manner. The crank side of the sprocket 50 is shown in FIG. 3 , which is the outer plate side 54 of the sprocket. The outer plate side also faces away from the vehicle to which it is attached. The opposite side of the outer plate side 54 of the sprocket 50 is the inner plate side 56. The inner plate side 56 faces the vehicle.

Generally speaking, a force applied to the crank arm 48 (e.g., typically in a downward direction) causes the chain ring 50 to rotate in the same direction (clockwise). The rotation of the chain ring 50 causes the chain 10 to be pulled around the chain ring and advance.

The chain ring 50 has a number of teeth 52 formed around a circumference 51 of the chain ring, the total number of the number of teeth being an even number. The number of teeth 52 includes a first set of teeth 58 and a second set of teeth 60 arranged in a staggered manner, wherein the number of the first set of teeth is equal to the number of the second set of teeth. In the most general form of the present invention, the first set of teeth 58 is configured to be received and fitted in the outer chain spaces 40, and the second set of teeth 60 is configured to be received and fitted in the inner chain spaces 42.

The overall shape of the circumference 51 of the chain ring can be generally circular or non-circular, such as elliptical, oval, polygonal or parabolic. All examples of the chain rings provided here all show a circumference 51 with a circular shape.

Each first set of teeth 58 is connected to the chain 10 via an outer chain space 40. Each second set of teeth 60 is connected to the chain 10 via an inner chain space 42.

Turning to Figure 12, the shape of each second set of teeth 60 is generally rectangular in cross-section, especially at or near the bottom or root of the teeth. This cross-section is taken through a plane parallel to the top surface 80 of the teeth and passing through the base circle position of the teeth, that is, approximately between the tooth root circle and the tooth top circle.

The rectangular cross-section and overall width WO ₁ of each second set of teeth 60 need to closely match the configuration of each inner chain space 42 (FIG. 1). The cross-section shown by each second set of teeth 60 shows that the outer plate side 54 is generally planar and the inner plate side 56 is also generally planar. Each second set of teeth 60 can occupy about 75% of the axial distance D ₁ of a corresponding space in the chain 10. Preferably, each second set of teeth 60 can occupy about 80% of D ₁ of a corresponding space in the chain 10. More preferably, each second set of teeth 60 can occupy about 85% of D ₁ of a corresponding space in the chain 10.

Turning to FIGS. 13-15, the first set of teeth 58 (see FIG. 3) has another form of teeth 58a, 58b, 58c, each of which has a longitudinal length _LT equal to that of the second set of teeth 60 (FIG. 12) in a cross-sectional view through the teeth as shown in FIG. 12. Each first set of teeth 58 may occupy about 75% of the distance _D2 of a corresponding space in the chain 10. Preferably, each first set of teeth 58 may occupy about 80% of the distance _D2 of a corresponding space in the chain 10. More preferably, each first set of teeth 58 may occupy about 85% of the distance _D2 of a corresponding space in the chain 10.

Each first set of teeth 58 has the additional feature of an outer plate side or first protrusion 62 on the outer plate side 54 of each other type of teeth 58a, 58b, 58c. In one embodiment, the first protrusion is asymmetrically disposed on one side of the first set of teeth along the circumferential direction of the chain ring. FIG. 13 also shows that the inner plate side 56 of the teeth 58a can be the same as the inner plate side 56 of each second set of teeth 60 (i.e., without the protrusion). The first protrusion 62 is configured to fit within a corresponding portion of the outer chain space 40 of the chain 10 (FIG. 1) and has a width _W1 . The function of the protrusion 62 is to help maintain the chain 10 on the chain ring 50 (FIG. 3). The protrusion 62 makes the total width WO ₂ of each tooth 58 a larger than the total width WO ₁ of each tooth 60 by the width of the protrusion 62 .

FIG. 14 is another embodiment of the first set of teeth 58, a tooth 58b. Specifically, the tooth 58b is similar to the tooth in FIG. 13, but has the additional feature of an inner or second protrusion 64 on the inner plate side 56 of the tooth. The width _W2 of the protrusion 64 is less than the width _W1 of the protrusion 62 of the tooth 58a, or it can be greater than _W1 . The protrusions 62, 64 make the total width _WO3 of each tooth 58b greater than the total width _WO1 of each tooth 60, which is different from the width of the protrusions 62, 64. In addition, _WO3 is greater than _WO2 .

FIG. 15 is a tooth 58c of another embodiment of the first set of teeth 58. Specifically, the tooth 58c is similar to the tooth in FIG. 14, and has an inner or second protrusion 66 on the inner plate side 56 of the tooth. The width _W1 of the protrusion 66 is equal to the width _W1 of the protrusion 62 of the tooth 58a. The protrusions 62, 66 make the total width _WO4 of each tooth 58c greater than the total width _WO1 of each tooth 60, which is different from the width of the protrusions 62, 66. In addition, _WO4 is greater than _WO3 .

It will be appreciated that various configurations of the teeth 58 may include protrusions positioned along one or both sides of each tooth at locations that function effectively to help position the chain on the chain ring 50, including locations adjacent to or at the base of each tooth or higher on each tooth.

4 and 6 show the outer plate side 54 and the transmission direction DD of the chain ring 50. The first set of teeth 58 and the second set of teeth 60 are arranged in a staggered manner.

The configuration of the second set of teeth 60 can be defined by forming a link receiving recess 72 on the outer plate side 54 and the inner plate side 56 of each of the teeth 60 by removing material from the sides of the teeth 60 by the chain ring 50. The link receiving recess 72 is also used to define the cross-sectional shape of each set of teeth 58. The link receiving recess 72 defines the outer plate side 54 and the inner plate side 56 of each of the teeth and extends from the front tooth flank 68 of one of the set of teeth 58 to the rear tooth flank 70 of the adjacent set of teeth in the transmission direction DD. Each link receiving recess 72 is configured to accommodate an inner link plate 22 length _LP (Figure 6) of the chain. Each recess 72 has a base surface 72a extending in the axial direction and a wall portion 72b extending in the radial direction (FIG. 7). The base surface 72a may form a smooth curved contour and may be roughly U-shaped.

FIG. 5 is a more detailed outline of each of the teeth 58, 60. The link receiving recess 72 is formed in the chain ring 50 and can be seen extending along the side of each second set of teeth 60 and extending in the transmission direction DD from the load-bearing side, i.e., the front or leading tooth flank 68 of one of the sets of teeth 58 to the rear tooth flank 70 of the adjacent set of teeth 58. In one embodiment, the front tooth flank and the rear tooth flank are asymmetrical relative to each other along the circumferential direction of the chain ring. The recess 72 is configured to accommodate the length _LP (FIG. 6) of an inner chain plate 22. Each tooth may have a top surface 80. The base surface 72a may extend to the top surface 80 of each tooth 58. The front flank 68 of each tooth includes a contact area 74 where a roller 24 (FIG. 1) contacts the tooth.

Above the contact area 74 is an optional tip 76. The roller 24 does not contact the tip 76 under normal driving conditions. The tip 76 can protrude forward a distance T from a line drawn along the contact area 74. The protruding tip 76 has the function of connecting the chain earlier than a chain ring without a tip and provides a better guiding effect of the chain. In one embodiment, the front tooth flank includes a radially outward portion radially outward from the contact area, wherein the contact area has a slope along the peripheral direction of the chain ring, and the radially outward portion has a different slope along the peripheral direction of the chain ring.

An optional hook 78 is a feature that can be formed on the rear flank 70 of each of the teeth 58, 60. The hook 78 is positioned along the rear flank 70 and can cooperate with the tip 76 to provide better guidance of the chain. In one embodiment, the hook includes a radial portion. For example, the hook 78 can include a portion of the rear flank 70 that is aligned with the radial direction R.

Turning to FIG. 7, the first set of teeth 58 and the second set of teeth 60 of the chain ring 50 are arranged in a staggered manner. An optional feature of each of the first set of teeth 58 and the second set of teeth 60 is a respective outer chamfer 82a, 82b. The first set of teeth 58 each has an outer chamfer 82a, which can be an arcuate surface formed on the outer plate side 54 or shoulder of each tooth. The second set of teeth 60 each has an outer chamfer 82b, which can be an arcuate surface formed on the outer plate side 54 or shoulder of each tooth. The length _C1 of the outer chamfer 82b of each tooth 60 can be greater than the length _C2 of the outer chamfer 82a of each tooth 58.

Turning to Figures 8 and 9, the chain 10 is positioned and connected to the chain ring 50. The outer link 12 is positioned on the first set of teeth 58. The inner link 14 is positioned on the second set of teeth 60.

Figures 10 and 11 are front views of the chain ring 50 without and with the chain 10, respectively. In one embodiment, a plane divides the chain ring into an outer plate side and an inner plate side relative to the outer plate side, wherein the tips of at least some of the first set of teeth are offset from the tips of at least some of the second set of teeth in a direction perpendicular to the plane. For example, a selective feature of all teeth 58, 60 of the chain ring 50 is that the center of the tooth tip top or top surface 80 is offset from the center line CL in a direction toward the inner plate side 56 of the chain ring. This offset feature can provide the chain 10 with a better guiding effect on one side of the chain ring.

Turning to FIG. 16 , a chain ring 50 includes a plurality of teeth 58, 60. A chain link 1 connected to the chain ring 50 is represented by line _L1 , and chain links 2 and 3 are represented by lines _L2 , _L3 , respectively. Lines _L1-3 are drawn between the axes of the chain rollers 24.

The hook 78 is shown as being disposed on the rear flank 70 of each tooth 58, 60. The hook 78 is positioned along the rear flank 70 and can cooperate with the pointed top 76 of the front flank 68 to provide better guidance of the chain. The hook 78 can include a portion of the rear flank 70 aligned in the radial direction R. The hook 78 has a radial extension 78a where the hook intersects the link centerline _L1-3 . Alternatively, the extension 78a can be higher than the centerline _L1-3 to provide more space for the roller to engage the teeth in the driving direction. The curve 90 is the path of the roller 24 when the roller 24 disengages the tooth.

In use, the chain 10 is installed so that each outer link 12 is disposed on one of the first sets of teeth 58 and each inner link 14 is disposed on one of the second sets of teeth 60. When the chain ring 50 is rotated by the crank 48, the chain 10 is pulled around the chain ring, and the outer links 12 and inner links 14 are sequentially engaged with the corresponding first and second sets of teeth 58, 60. As described in detail above, the various features of the chain ring 50 have the function of guiding and retaining the chain 10 thereon.

From the above discussion, it will be understood that the present invention can be embodied in a variety of embodiments, including but not limited to the following: Embodiment 1: A single chain ring of a bicycle front crank gear for connecting a transmission chain, comprising: A plurality of teeth formed around the chain ring, the plurality of teeth being composed of an even number; The plurality of teeth includes a first set of teeth and a second set of teeth alternately arranged between the first set of teeth; Wherein the first set of teeth and the second set of teeth have the same number; The first set of teeth and the second set of teeth each include an outer plate side and an inner plate side opposite to the outer plate side; Each of the first set of teeth includes at least one first protrusion on its outer plate side, and each of the second set of teeth does not have the first protrusions on the outer plate side and the inner plate side. Example 2: The chain ring as in Example 1, further including a second protrusion on the inner plate side of each of the first set of teeth. Example 3: The chain ring as in Example 2, wherein the first protrusion has a first width and the second protrusion has a second width, wherein the first width is equal to the second width. Example 4: The chain ring as in Example 2, wherein the first width is greater than the second width. Example 5: A chain ring as in Example 1, wherein each of the first set of teeth has a cross-shaped cross-section adjacent to one of the bases. Example 6: A chain ring as in Example 1, wherein each of the second set of teeth has a rectangular cross-section adjacent to one of the bases. Example 7: A chain ring as in Example 1, wherein each of the first set of teeth and the second set of teeth includes a front tooth flank, and wherein the front tooth flank includes a structure to guide the protruding tip of the chain. Example 8: A chain ring as in Example 1, wherein each of the first set of teeth and the second set of teeth includes a rear tooth flank, and wherein the rear front tooth flank includes a structure to guide the hook portion of the chain. Example 9: A chain ring as in Example 1, wherein each of the first set of teeth and the second set of teeth includes a front tooth flank and a rear tooth flank, wherein the front tooth flank of each tooth includes a protruding tip. Example 10:   A chain ring as in Example 9, wherein the rear tooth flank of each tooth includes a hook portion. Example 11:   A chain ring as in Example 10, wherein the hook portion includes a substantially radial direction portion. Example 12:   A chain ring as in Example 10, wherein the protruding tip cooperates with the hook of an adjacent tooth to guide the chain. Example 13:   A chain ring as in Example 1, wherein each tooth of the first set of teeth includes a radial outward chamfer having a first range along the outer plate side of each tooth. Example 14:   A chain ring as in Example 1, wherein each tooth of the second set of teeth includes a radial outward chamfer having a second range along the outer plate side of each tooth. Example 15:   A chain ring as in Example 1, wherein each of the first set of teeth includes an outer chamfer angle having a first range, and each of the second set of teeth includes an outer chamfer angle having a second range, and the first range is smaller than the second range. Example 16:   A chain ring as in Example 1, wherein the inner plate side and the outer plate side of each of the teeth of the second set of teeth each define a recess formed in the chain ring. Example 17:   A chain ring as in Example 16, wherein each recess is defined by an axially extending base surface and a radially extending wall. Embodiment 18:   A separate chain ring of a bicycle front crank gear for connecting a transmission chain, the transmission chain including interlaced inner and outer links, the chain ring comprising: A plurality of teeth formed around the chain ring, the plurality of teeth being composed of an even number; The plurality of teeth comprises a first set of teeth and a second set of teeth staggered between the first set of teeth; The first set of teeth and the second set of teeth have the same number; Each of the first set of teeth and the second set of teeth comprises an outer plate side and an inner plate side opposite to the outer plate side; The outer plate side and the inner plate side of each tooth of the second set of teeth respectively define a recess formed in the chain ring along each tooth of the second set of teeth. Example 19:   The chain ring as in Example 18, wherein each recess extends from the front tooth flank of a first tooth of the first set of teeth to the rear tooth flank of a second tooth of the first set of teeth, wherein the first tooth and the second tooth are adjacent to each other in a transmission direction in the first set of teeth. Example 20:   The chain ring of Example 18, further comprising a first protrusion on the outer plate side of each of the first set of teeth, and a second protrusion on the inner plate side of each of the first set of teeth, at least part of the first protrusion and the second protrusion being defined by the recess. Example 21:   The chain ring of Example 20, wherein the first protrusion has a first width and the second protrusion has a second width, wherein the first width is equal to the second width. Example 22:   The chain ring of Example 20, wherein the first width is greater than the second width. Example 23:   A chain ring as in Example 18, wherein each of the first set of teeth has a cross-shaped cross-section adjacent to its base defined by the recess. Example 24:   A chain ring as in Example 18, wherein each of the second set of teeth has a rectangular cross-section adjacent to its base defined by the recess. Example 25:   A chain ring as in Example 18, wherein each of the first set of teeth and the second set of teeth includes a front tooth flank, and wherein the front tooth flank includes a structure to guide a protruding tip of the chain. Example 26:   A chain ring as in Example 18, wherein each of the first set of teeth and the second set of teeth includes a rear tooth flank, and wherein the rear tooth flank includes a structure to guide the hook of the chain. Example 27:   A chain ring as in Example 18, wherein each of the first set of teeth and the second set of teeth includes a front tooth flank and a rear tooth flank, wherein the front tooth flank of each tooth includes a protruding tip. Example 28:   A chain ring as in Example 27, wherein the rear tooth flank of each tooth includes a hook. Example 29:   A chain ring as in Example 28, wherein the hook portion includes a substantially radial portion. Example 30:   A chain ring as in Example 28, wherein the protruding tip portion cooperates with an adjacent portion of the hook portion to guide the chain. Example 31:   A chain ring as in Example 18, wherein each of the first set of teeth includes a radial outward chamfer having a first range along the outer plate side of each tooth. Example 32:   A chain ring as in Example 18, wherein each of the second set of teeth includes a radial outward chamfer having a second range along the outer plate side of each tooth. Example 33:   The chain ring of Example 18, wherein each of the first set of teeth includes an outer chamfer angle having a first range, and each of the second set of teeth includes an outer chamfer angle having a second range, and the first range is smaller than the second range. Example 34:   The chain ring of Example 18, wherein the recess is formed by an axially extending base surface and a radially extending wall. Embodiment 35:   A bicycle crank gear plate, comprising: a bicycle crank arm; and a single chain ring, which is attached to the bicycle crank arm and can be connected to a transmission chain, the single chain ring includes: a plurality of teeth, which are formed around the chain ring, the plurality of teeth are composed of even numbers, the plurality of teeth include a first group of teeth and a second group of teeth alternately arranged between the first group of teeth, wherein the number of the first group of teeth is the same as that of the second group of teeth; Each of the first set of teeth and the second set of teeth includes an outer plate side and an inner plate side opposite to the outer plate side, wherein each of the first set of teeth includes at least one first protrusion on its outer plate side, and each of the second set of teeth does not have a first protrusion on the outer plate side and the inner plate side. Example 36:   The bicycle crank plate as in Example 35, further including a second protrusion on the inner plate side of each of the teeth of the first set of teeth. Example 37:   The bicycle crank plate as in Example 36, wherein the first protrusion has a first width and the second protrusion has a second width, wherein the first width is equal to the second width. Example 38:   A bicycle crank gear as in Example 36, wherein the first width is greater than the second width. Example 39:   A bicycle crank gear as in Example 35, wherein each of the first set of teeth has a cross-shaped cross-section adjacent to its base. Example 40:   A bicycle crank gear as in Example 35, wherein each of the second set of teeth has a rectangular cross-section adjacent to its base. Example 41:   A bicycle crank gear as in Example 35, wherein each of the first set of teeth and the second set of teeth includes a front tooth flank, and wherein the front tooth flank includes a structure to guide the protruding tip of the chain. Example 42:   A bicycle crank gear as in Example 35, wherein each of the first set of teeth and the second set of teeth includes a rear tooth flank, and wherein the rear tooth flank includes a structure to guide the hook of the chain. Example 43:   A bicycle crank gear as in Example 35, wherein each of the first set of teeth and the second set of teeth comprises a front tooth flank and a rear tooth flank, wherein the front tooth flank of each tooth comprises a protruding tip. Example 44:   A bicycle crank gear as in Example 43, wherein the rear tooth flank of each tooth comprises a hook. Example 45:   A bicycle crank gear as in Example 44, wherein the hook comprises a substantially radial portion. Embodiment 46:   A bicycle crank gear as in embodiment 45, wherein the protruding tip cooperates with a hook of an adjacent tooth to guide the chain.

Although the present invention has been described in detail with reference to specific embodiments, it should be understood that many variations are possible within the spirit and scope of the concepts described in the present invention. Accordingly, the present invention is not limited to the disclosed embodiments, but shall be of the full scope permitted by the terms of the following claims.

10: Drive chain, roller chain, chain, roller drive chain 12: Outer link 14: Inner link 16,18: Pin 20: Outer plate, chain plate 22: Inner plate, chain plate 24: Roller 30: Hole 32,34,36: End 38: Narrow middle 40: Outer chain space 42: Inner chain space 48: Crank arm, crank 50: Chain ring 51: Ring 54: Outer plate side 56: Inner plate side 58: First set of teeth, teeth 58a,58b,58c: teeth 60: second set of teeth, teeth 62: first convex part, convex part 64,66: second convex part, convex part 68: front tooth flank, tooth flank 70: rear tooth flank 72: link receiving recess, recess 72a: base surface 72b: wall 74: contact area 76: pointed top 78: hook part 78a: outermost extension 82a,82b: outer chamfer 80: top surface

In the diagram:

Figure 1 is a top view of a conventional transmission chain;

FIG. 2 is a side view of the conventional transmission chain of FIG. 1;

FIG. 3 is an isometric view of the assembled transmission chain and chain rings connected by a transmission system according to the present invention;

FIG. 4 is a side view of a chain ring according to the present invention;

FIG5 is an enlarged view of the chain link in FIG4;

FIG. 6 is a side view of the assembled transmission chain and chain rings according to the present invention connected by a transmission system but with the outer chain plate removed;

FIG. 7 is a front isometric view of the chain ring according to the present invention;

FIG8 is a front isometric view of the chain ring connected to a transmission chain according to FIG7;

FIG. 9 is a rear isometric view of the chain ring connected to a transmission chain according to FIG. 7;

FIG. 10 is a front view of the chain ring according to the present invention;

FIG. 11 is a front view of the chain ring connected to a transmission chain according to the present invention;

FIG. 12 is a cross-sectional view of a gear tooth according to one embodiment of a set of teeth, taken along the line B-B of FIG. 5;

Figures 13-15 are cross-sectional views of a gear tooth different from the tooth of Figure 12 and according to another embodiment of another set of teeth, taken along line A-A of Figure 5; and

FIG. 16 is a partial side view of the chain ring and a roller of a chain connected to the chain ring by a tooth according to the present invention.

50: Chain

51: Ring

54: Outer plate side

56: Inner panel side

58: The first set of teeth, teeth

60: Second set of teeth, teeth

68: Anterior Teeth

70: Posterior ventral part

72: Chain receiving recess

Claims (16)

A bicycle chain ring for connecting a transmission chain, comprising: A plurality of teeth extending from a circumference of the chain ring, wherein the roots of the plurality of teeth are arranged adjacent to the circumference of the chain ring; The plurality of teeth include a first set of teeth and a second set of teeth, each tooth in the first set of teeth being wider than each tooth in the second set of teeth; At least some of the teeth in the second set of teeth are staggered between and adjacent to the first set of teeth; and The first set of teeth includes a tooth flank, the contour of which extends in one direction to a radial extension and extends beyond the radial extension in a different direction. A bicycle chain ring as claimed in claim 1, wherein the tooth belly includes a hook portion. A bicycle chain ring as claimed in claim 2, wherein the radial extension is an outermost extension of the hook portion. A bicycle chain ring as claimed in claim 3, wherein the hook portion is formed in a portion of the tooth in the tooth belly, and the portion is narrower than a widest portion of the first set of teeth. A bicycle chain ring as claimed in claim 4, wherein the tooth flank is a rear tooth flank. As in the bicycle chain ring of claim 4, the hook portion is assembled to connect a roller of the transmission chain. A bicycle chain ring as claimed in claim 1, wherein a portion of the second set of teeth that is wider than the first set of teeth is formed as at least one protrusion. A bicycle chain ring as claimed in claim 7, wherein the at least one protrusion includes a first protrusion on a first side of the chain ring. A bicycle chain ring as claimed in claim 8, wherein the at least one protrusion includes a second protrusion on a second side of the chain ring. A bicycle chain ring as claimed in claim 9, wherein the first protrusion has a first width, and the second protrusion has a second width, and the first width is greater than the second width. A bicycle chain ring as claimed in claim 9, wherein the first protrusion has a first width, and the second protrusion has a second width, and the first width is equal to the second width. A bicycle chain ring as claimed in claim 9, wherein the first protrusion is asymmetrically arranged on the first side of the chain ring along the circumferential direction of the chain ring. A bicycle chain ring as claimed in claim 1, wherein the tooth flank is a first tooth flank, and the first set of teeth further includes a second tooth flank, and the first tooth flank and the second tooth flank have different shapes when viewed from an axis upward. A bicycle chain ring as claimed in claim 1, wherein the plurality of teeth are composed of an even number. A bicycle chain ring as claimed in claim 1, wherein the plurality of teeth are suitable for coupling with a bicycle roller drive chain, the bicycle roller drive chain having staggered outer links and inner links that define outer chain spaces and inner chain spaces, respectively, wherein the size and shape of each tooth in the first set of teeth are configured so that it is suitable for fitting within one of the outer chain spaces, and the size and shape of each tooth in the second set of teeth are configured so that it is suitable for fitting within one of the inner chain spaces. A bicycle chain ring as claimed in claim 1, wherein a front tooth flank of each of the plurality of teeth includes a contact area in which a roller of the drive chain contacts the front tooth flank.