Patent Description:
The present invention is generally directed to bicycle sprockets and cassette assemblies. More specifically, the present invention is directed to a multi-piece bicycle cassette with a clamping connection for connecting the bicycle cassette to a bicycle hub driver body.

On a bicycle, the cassette comprises a series of sprockets which attach to a hub driver of the rear wheel. The cassette comprises a series of appropriately sized sprockets which are_typically chosen for a specific riding style and/or a riding location. For example, a cassette with a series of smaller sprockets is useful for fast riding and in a flatter location, while a cassette with a series of larger sprockets can be useful for climbing and in a hilly location. The cassette with the desired number and size of sprockets is typically attached to the hub driver body using a locking ring for securing the whole cassette to the hub.

Relevant documents for the present invention are <CIT>, <CIT>, <CIT> and <CIT> disclosing a bicycle cassette with a large sprocket sub-assembly comprising clamping mechanisms to attach the sub-assembly to the bicycle hub; and documents <CIT> and <CIT> disclosing a small sprocket sub-assembly attachment to the large sprocket sub-assembly.

A bicycle cassette comprises a clampstyle connection for connecting the bicycle cassette to a bicycle hub driver body. The bicycle cassette is attached to a bicycle hub driver body by incorporating a clamp structure into one portion of the cassette, which then rigidly clamps onto the driver body of the bicycle hub. In addition, when combined with a bayonet style attachment structure between two parts of the cassette, it allows for the use of a smaller sprocket on one segment of the cassette. Specifically, it allows a small <NUM> or <NUM> tooth sprocket to overhang the cassette driver body on a bicycle hub, by attaching the small cog assembly to a larger cog assembly using a bayonet style attachment. In a first aspect, a bicycle cassette comprises a large sprocket sub-assembly comprising a clamping mechanism for attaching the large sprocket sub-assembly to a rear bicycle hub and a small sprocket sub-assembly, wherein the small sprocket sub-assembly rotatably couples with and locks to the large sprocket sub-assembly after the large sprocket assembly is clamped to the rear bicycle hub to form the bicycle cassette. The large sprocket sub-assembly clamps to the rear bicycle hub by tightening a clamp screw. In some embodiments, the small sprocket sub-assembly is coupled to the large sprocket assembly using a locking bayonet style attachment. In some embodiments, the small sprocket sub-assembly comprises a <NUM> tooth sprocket. In further embodiments, the small sprocket sub-assembly comprises a <NUM> tooth sprocket. In some embodiments, the large sprocket sub-assembly comprises a <NUM> tooth sprocket. In further embodiments, the large sprocket sub-assembly comprises a <NUM> tooth sprocket. In still further embodiments, the large sprocket sub-assembly comprises a <NUM> tooth sprocket. In some embodiments, the large sprocket sub-assembly comprises a sprocket with more than <NUM> teeth. In some embodiments, the large sprocket sub-assembly and the small sprocket assembly are manufactured from different materials. In some embodiments, the small sprocket sub-assembly overhangs a cassette driver body of the bicycle hub in an assembled configuration. In some embodiments, the small sprocket sub-assembly comprises a bushing, which radially supports said small sprocket sub-assembly on the cassette driver body of the bicycle hub in the assembled configuration.

In another aspect, a bicycle cassette and hub system comprises a rear bicycle hub, a hub driver assembly coupled to the rear bicycle hub and a cassette assembly clamped to the hub driver assembly, the cassette assembly comprising a large sprocket sub-assembly comprising a clamping mechanism for clamping the large sprocket sub-assembly to the hub driver assembly and a small sprocket sub-assembly, wherein the small sprocket sub-assembly rotatably couples with and locks to the large sprocket sub-assembly after the large sprocket assembly is clamped to the rear bicycle hub to form the bicycle cassette assembly. In some embodiments, the large sprocket sub-assembly clamps to the hub driver assembly by tightening a clamp screw. In some embodiments, the small sprocket sub-assembly is coupled to the large sprocket sub-assembly using a locking bayonet style attachment. In some embodiments, the small sprocket sub-assembly comprises a <NUM> tooth sprocket. In further embodiments, the small sprocket sub-assembly comprises a <NUM> tooth sprocket. In some embodiments, the large sprocket sub-assembly comprises a <NUM> tooth sprocket. In further embodiments, the large sprocket sub-assembly comprises a <NUM> tooth sprocket. In still further embodiments, the large sprocket sub-assembly comprises a <NUM> tooth sprocket. In some embodiments, the large sprocket sub-assembly comprises a sprocket with more than <NUM> teeth. In some embodiments, the large sprocket assembly and the small sprocket assembly are manufactured from different materials. In some embodiments, the small sprocket sub-assembly overhangs the hub driver assembly in an assembled configuration. In some embodiments, the small sprocket sub-assembly comprises a bushing, which radially supports said small sprocket sub-assembly on the cassette driver body of the bicycle hub in the assembled configuration.

In a further aspect, a method of attaching a bicycle cassette to a hub comprises sliding a large sprocket sub-assembly onto a hub driver body to engage the large sprocket assembly to the hub, clamping the large sprocket sub-assembly onto the hub by tightening a clamp screw of the large sprocket sub-assembly, sliding a small sprocket sub-assembly onto the hub driver body and attaching the small sprocket sub-assembly to the large sprocket assembly to form the bicycle cassette. In some embodiments, the small sprocket sub-assembly rotatably couples with and locks to the large sprocket assembly to form the bicycle cassette. In some embodiments, the small sprocket sub-assembly couples to the large sprocket sub-assembly using a locking bayonet style attachment.

Several example embodiments are described with reference to the drawings, wherein like components are provided with like reference numerals. The example embodiments are intended to illustrate, but not to limit, the invention. The drawings include the following figures:.

Embodiments of the invention are directed to a bicycle cassette comprising a clampstyle connection for connecting the bicycle cassette to a bicycle hub driver body. The bicycle cassette is attached to a bicycle hub driver body by incorporating a clamp structure into one portion of the cassette, which then rigidly clamps onto the driver body of the bicycle hub. In addition, when combined with a bayonet style attachment structure between two parts of the cassette, it allows for the use of a smaller sprocket on one segment of the cassette. Specifically, it allows a small <NUM> or <NUM> tooth sprocket to overhang the cassette driver body on a bicycle hub, by attaching the small cog assembly to a larger cog assembly using a bayonet style attachment.

Reference will now be made in detail to implementations of a bicycle cassette with a clamping connection as illustrated in the accompanying drawings. The same reference indicators will be used throughout the drawings and the following detailed description to refer to the same or like parts. In the interest of clarity, not all of the routine features of the implementations described herein are shown and described. It will be appreciated that in the development of any such actual implementation, numerous implementation-specific decisions can be made in order to achieve the developer's specific goals, such as compliance with application and business related constraints, and that these specific goals will vary from one implementation to another and from one developer to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking of engineering for those of ordinary skill in the art having the benefit of this disclosure.

Referring now to <FIG>, a complete cassette assembly <NUM> is depicted therein. The complete cassette assembly is installed on the right side of a rear bicycle hub <NUM>.

<FIG> shows the rear bicycle hub <NUM> prior to installation of the complete cassette assembly <NUM>, including the hub driver assembly <NUM>.

As shown within <FIG>, the hub driver assembly <NUM> includes a hub driver body <NUM>, an outboard hub driver bearing <NUM>, a hub driver torque coupling <NUM>, a hub driver cassette stop face <NUM>, a hub driver thread <NUM> and a hub driver right-end radial surface <NUM>.

As shown within <FIG>, a complete cassette assembly <NUM> includes a cassette large sprocket sub-assembly <NUM>, a cassette small sprocket sub-assembly <NUM>, and a cassette locking screw <NUM>.

As shown within <FIG>, a cassette small sprocket sub-assembly <NUM> includes a cassette small sprocket portion <NUM> and a cassette small sprocket bushing <NUM>. The cassette small sprocket bushing <NUM> includes a bushing flange <NUM>, a bushing outer stepped surface <NUM> and a bushing inner stepped surface <NUM>.

<FIG> shows a cassette small sprocket portion <NUM>. The small sprocket portion <NUM> includes <NUM> small portion sprockets 60a, 60b, 60c, 60d, 60e, 60f, <NUM>, <NUM>, 60i, and 60j, and a small sprocket portion axle clearance hole <NUM>.

<FIG> shows a cassette small sprocket portion <NUM>, which includes locking tangs 64a, 64b, 64c, 64d, 64e, 64f, and a small sprocket portion locking hole <NUM>. The small sprocket portion <NUM> also includes a first small sprocket portion axial locating face <NUM>, a second small sprocket portion axial locating face <NUM>, a first small sprocket portion locating bore <NUM> and a second small sprocket portion locating bore <NUM>, and a small sprocket portion large end face <NUM>.

<FIG> shows a right side view of the cassette small sprocket sub-assembly <NUM>, including said small portion sprockets 60a, 60b, 60c, 60d, 60e, 60f, <NUM>, <NUM>, 60i, and 60j.

<FIG> shows a cross section of the cassette small sprocket sub-assembly <NUM>. The cassette small sprocket bushing <NUM> is assembled into the cassette small sprocket portion <NUM> such that the cassette outer stepped surface <NUM> fits inside the first small sprocket portion locating bore <NUM> and the second small sprocket portion locating bore <NUM>.

<FIG> shows an exploded view of the cassette large sprocket sub-assembly <NUM>, which includes the large sprocket portion <NUM> and the large sprocket clamp screw <NUM>. <FIG> also shows a large portion clamp <NUM>.

<FIG> shows a right side isometric view of the cassette large sprocket portion <NUM>, including the clamp screw clearance hole <NUM>, clamp flexure slot <NUM>, and clamp clearance slot <NUM>. It also shows the clamp boss end face <NUM> and clamp contact surface <NUM>, and the locking flanges 114a, 114b, 114c, 114d, 114e, and 114f.

<FIG> shows a rear view of the large sprocket portion <NUM> and the large sprocket driver torque coupling <NUM>. The large sprocket driver torque coupling <NUM> is comprised of a driver torque coupling stop face <NUM>, a torque coupling spline tooth <NUM>, a torque coupling spline recess <NUM>, and a torque coupling spline end face <NUM>. The large sprocket portion <NUM> also includes a driver thread clearance bore and a clamp inner end face <NUM> and the clamp contact surface <NUM>.

<FIG> illustrate the large sprocket portion <NUM> and the large sprocket cassette torque coupling <NUM>. The large sprocket cassette torque coupling <NUM> includes a repeated patterned torque receiving face <NUM>, a repeated patterned locking flange cutout <NUM>, a repeated patterned locking flange radial surface <NUM>, a repeated patterned locking flange inside surface <NUM>, and a repeated patterned large sprocket portion offset boss <NUM>.

<FIG> illustrate the cassette small sprocket portion <NUM>, including a detail view of a locking tang 64c, which comprises a torque driving face <NUM> and a tang inside surface <NUM>.

<FIG> illustrate the cassette small sprocket portion <NUM>, showing the surface defining the locking tang radial clearance <NUM>. <FIG> shows a torque driving face <NUM> and an isometric view of a locking tang standoff <NUM>. <FIG> also shows another view of the locking tang 64f, and the locking tang axial clearance <NUM>.

<FIG> shows a broken out section view of the complete cassette assembly <NUM> with the cassette large sprocket sub-assembly <NUM> and the cassette small sprocket sub-assembly <NUM> in the unlocked, installation position. In this orientation, a locking tang 64a is aligned with a locking flange cutout <NUM>, so that the cassette small sprocket sub-assembly <NUM> may slide into place on the hub driver assembly <NUM>.

<FIG> shows the same broken-out section view with the cassette small sprocket sub-assembly <NUM> rotated clockwise so that the small sprocket portion assembly is locked to the cassette large sprocket sub-assembly <NUM>. In this orientation a locking tang radial clearance <NUM> couples with a locking flange radial surface <NUM>. The cassette locking screw <NUM> is installed through the small sprocket portion locking hole <NUM> and threaded into the locking screw receiving hole <NUM> (not visible).

<FIG> shows a left side view of the complete cassette assembly <NUM> with the cassette large sprocket sub-assembly <NUM> and the cassette small sprocket sub-assembly <NUM> in the unlocked, installation position. In this view, a torque driving face <NUM> is not yet in contact with a torque Receiving Face <NUM>.

<FIG> shows the same broken out section view as <FIG> of the complete cassette assembly <NUM> with the cassette large sprocket sub-assembly <NUM> and the cassette small sprocket sub-assembly <NUM> rotated clockwise into the locking position. In this view, a torque driving face <NUM> is in contact with a torque receiving face <NUM>.

<FIG> shows a top view of the cassette large sprocket sub-assembly <NUM>. <FIG> shows a right side section view of the cassette large sprocket sub-assembly <NUM>, including the cassette locking screw <NUM> which passes through the clamp screw clearance hole <NUM>, bridges the clamp clearance slot <NUM> and threads into the clamp screw threaded hole <NUM>.

<FIG> show a cross section of the complete cassette assembly <NUM> mounted to the hub driver assembly <NUM>. Shown in the cross section are many of the critical features of the complete cassette assembly <NUM> in their mounted and locked configuration. The cassette assembly <NUM> is built on the hub driver assembly <NUM>, which includes a hub driver body <NUM>. Two bearings, an outboard hub driver bearing <NUM> and an inboard hub driver bearing <NUM> are fitted in the inner hub driver bearing bore <NUM>.

The large sprocket portion <NUM> is fitted onto the hub driver body <NUM> so that the large sprocket driver torque coupling <NUM> engages the hub driver torque coupling <NUM>, and the large sprocket coupling stop face <NUM> contacts the hub driver cassette stop face <NUM>.

The cassette small sprocket sub-assembly <NUM> is installed on the cassette large sprocket sub-assembly <NUM> and the hub driver assembly <NUM>, so that the cassette small sprocket bushing <NUM> rests on the hub driver right-end radial surface <NUM>.

The locking flange <NUM> is coupled between the locking tang <NUM> and the first small sprocket portion axial locating face <NUM>.

As shown in <FIG>, in some embodiments, a hub driver assembly <NUM> includes a hub driver body <NUM>, an outboard hub driver bearing <NUM>, a hub driver torque coupling <NUM>, a hub driver cassette stop face <NUM>, a hub driver thread <NUM> and a hub driver right-end radial surface <NUM>.

<FIG> shows a cassette large sprocket sub-assembly <NUM> with the cassette locking screw <NUM> installed, coupled to said hub driver assembly <NUM>, prior to installation of the cassette small sprocket sub-assembly <NUM>.

A complete cassette assembly <NUM> is able to be assembled onto a rear bicycle hub <NUM> using tools known to bicycle mechanics and others familiar with bicycle construction and assembly. In some embodiments, the tools needed for assembly of the cassette assembly <NUM> as shown in the drawings are a hex key or other tool fitted to the cassette locking screw <NUM> and the cassette clamp screw <NUM>. In some embodiments, assembly may accomplished by using the same tool interface on said screws, such that one tool is sufficient to assemble or mount and/or demount the cassette assembly <NUM> from the hub <NUM>.

To assemble the complete cassette assembly <NUM>, the cassette large sprocket sub-assembly <NUM> is slid over the hub driver right-end radial surface <NUM> towards the left end of the rear bicycle hub <NUM> until the large sprocket driver torque coupling <NUM> is engaged with the hub driver torque coupling <NUM>. The large sprocket coupling stop face <NUM> is pressed against the hub driver cassette stop face <NUM>.

Once the cassette large sprocket sub-assembly <NUM> is completely engaged on the hub <NUM>, the large sprocket clamp screw <NUM> is tightened to an appropriate torque value using the hex key or other tool. Applying torque to the screw closes the clamp clearance Slot <NUM>, and creates pressure between the clamp contact surface <NUM> and the hub driver right-end radial surface <NUM>, which in turn prevents the large sprocket sub-assembly <NUM> from moving on the hub driver body <NUM>.

In some embodiments, the thread clearance bore <NUM> on the large sprocket portion <NUM> allows the large sprocket portion to assemble to the hub driver body <NUM> without use of the hub driver thread <NUM>. Particularly, in some embodiments, the hub driver body <NUM> is made without a driver thread.

After tightening the large sprocket clamp screw <NUM>, the cassette small sprocket sub-assembly <NUM> is able to be installed. To install the small sprocket sub-assembly <NUM>, the bushing inner stepped surface <NUM> is aligned with the hub driver right-end radial surface <NUM>, and the locking tangs <NUM> are aligned with the locking flange cutouts <NUM>.

After proper alignment, the cassette small sprocket sub-assembly <NUM> is slid towards the left end of the rear bicycle hub <NUM> until the second small sprocket portion axial locating face <NUM> contacts the locking flange inside surface face <NUM>. Once the cassette small sprocket sub-assembly <NUM> is in place, it is able to be rotated by hand or with the use of a tool in the clockwise direction relative to the cassette large sprocket sub-assembly <NUM>, until a torque driving face <NUM> contacts a torque receiving face <NUM>. At this point the cassette small sprocket sub-assembly <NUM> can no longer move to the left along the hub axis because the locking flanges <NUM> are contained between the first small sprocket portion axial locating face <NUM> and the locking tangs <NUM>.

Next, the cassette locking screw <NUM> is inserted into the locking screw receiving hole <NUM> through the small sprocket portion locking hole <NUM>, and tightened using an appropriate tool. Once appropriate torque has been applied to said screw, the cassette is fully installed.

To disassemble the cassette small sprocket sub-assembly <NUM> from the cassette large sprocket sub-assembly <NUM>, the cassette locking screw <NUM> is unthreaded from the locking screw receiving hole <NUM> using an appropriate tool. Once the screw <NUM> is unthreaded, it may be set aside.

Next, the cassette large sprocket sub-assembly <NUM> is held stationary, while the cassette small sprocket sub-assembly <NUM> is rotated counter-clockwise until the locking tangs <NUM> are aligned with the locking flange cutouts <NUM>. When the locking tangs <NUM> are aligned with the locking flange cutouts <NUM>, it is possible to slidably remove the small sprocket sub-assembly <NUM> from the rear bicycle hub <NUM>.

After the small sprocket sub-assembly <NUM> is removed from the rear bicycle hub <NUM>, the large sprocket clamp screw <NUM> is able to be loosened with an appropriate tool. Once the screw <NUM> is loosened, tension is relieved in the large portion clamp <NUM>. With tension relieved, the cassette large sprocket sub-assembly <NUM> is able to be removed from the hub driver assembly <NUM>.

With the cassette assembly <NUM> installed, tension in a bicycle chain applies a clockwise torque to one of the sprockets of the complete cassette assembly <NUM>, including the large portion sprocket <NUM>, or small sprocket portion sprockets <NUM>(a-j). When torque is applied to the small portion sprockets, torque is transferred to the cassette large sprocket sub-assembly <NUM> through the torque driving face <NUM> / torque receiving face <NUM> interface. The torque is then transferred to the hub driver assembly <NUM> through the hub driver torque coupling <NUM> / large sprocket driver torque coupling <NUM> interface. The cassette locking screw <NUM> resists spontaneous disassembly from abnormal chain loads encountered during bicycle riding activity.

As described above, an assembled cassette <NUM> shows <NUM> sprockets, ranging from <NUM> teeth on the smallest sprocket to <NUM> teeth on the largest sprocket. Alternative embodiments of the cassette could include anywhere from <NUM> to <NUM> sprockets. Current bicycle drivetrains consist of between <NUM> and <NUM> sprockets in the rear cassette. However, an assembled cassette is able to utilize any appropriately desired number of sprockets. For example, in some embodiments, the cassette is able to comprise <NUM>, <NUM> or <NUM> sprockets attached to the rear hub of a bicycle.

In some embodiments, some or all of the sprockets in the assembly are stamped from sheet material and riveted or attached through some other method to a series of central carriers which contain the torque-transferring features of the invention. For instance, one or more steel sprockets could be riveted or otherwise fixed to a central aluminum piece to form the cassette large sprocket sub-assembly <NUM>. The same construction method is able to be used for the cassette small sprocket portion <NUM>.

Alternatively, in some embodiments, some or all of the sprockets on the cassette small sprocket portion <NUM> are manufactured from a different material and attached to the remaining small sprocket portion <NUM>, such that lightweight materials such as aluminum or titanium could be used for some sprockets on the portion, while others were machined directly onto the portion. In this way, weight and durability is able to be fine-tuned as seen fit by the designer.

In further embodiments, the large sprocket portion <NUM> is able to be combined with the hub driver body <NUM> and manufactured from one piece of material. In this case, the large portion clamp <NUM> is able to be eliminated, and assembly would be further simplified.

In still further embodiments, the number of repeated circular arrangement of features on the cassette could be considered. For instance, while six locking tangs <NUM> are shown in the preferred embodiment, any appropriately desired number could be used. For example, in some embodiments, <NUM> to <NUM> locking tangs are use. However, more or less are able to be added as necessary. Similarly, while one cassette locking screw <NUM> is shown, two or more screws could be utilized to add redundancy to the assembly.

Additionally, in some embodiments, the number of torque transferring feature sets (torque receiving face <NUM> / torque driving face <NUM>, locking tangs <NUM>, locking tang pads <NUM>) are able to be increased or decreased as necessary to suit different space constraints and different usage cases, using more features for higher torque loads and less features for less rigorous applications. Also there is no strict requirement that the number of torque interfaces match the number of tang interfaces, so axial retention could be separated from torque driving capacity if necessary or prudent.

In some embodiments, the orientation and location of the torque transferring features that pass torque between the cassette small sprocket sub-assembly <NUM> and the cassette large sprocket sub-assembly <NUM> are able to be altered. For instance, the locking tangs <NUM> are able to be oriented so that they grip the inside diameter of the locking flange <NUM>, rather than the outside diameter. Alternately, in some embodiments, the locking tangs <NUM> are able to project from the cassette large sprocket sub-assembly <NUM>, and the locking flange <NUM> is able to be located on the cassette small sprocket sub-assembly <NUM>, in effect reversing the orientation of the attachment features.

In addition, the locking mechanism is able to comprise any appropriately desired mechanism. For example, instead of the cassette locking screw <NUM>, spring loaded ball plungers are able to be substituted. Another alternative locking feature is a leaf spring arrangement whereby a formed leaf spring with a formed tooth is attached to the cassette large sprocket sub-assembly <NUM>, and the tooth acts on a machined feature of the cassette small sprocket sub-assembly <NUM>. Alternatively, in some embodiments, a set screw or other locking screw is used to lock the two pieces together once the cassette small sprocket sub-assembly <NUM> has been installed. In further embodiments, a screw threaded into a hole in the cassette small sprocket sub-assembly <NUM> is able to engage a hole or depression in the cassette large sprocket sub-Assembly <NUM>, or vice versa.

In further embodiments, a pin or plunger in shear is able to be installed in the large sprocket sub-assembly <NUM> or the cassette small sprocket sub-assembly <NUM> so that once the two assemblies are twisted together, the plunger or pin slides into a hole in the other piece and prevents back-rotation and disassembly of the two assemblies.

In some embodiments, the large portion clamp <NUM> is able to comprise a collet style clamp to provide adequate clamping force, where an externally threaded collet is formed on the cassette large sprocket portion <NUM> with the large portion clamp <NUM>. In this embodiment, the collet is able to comprise an external thread, a tapered outer surface, and several slots through the clamp. The collet is able to be clamped in place by installing an internally threaded nut with a mating tapered surface, such that when the nut is tightened and the tapered surfaces come together, the inside diameter of the clamp compresses the outside diameter of the hub driver right-end radial surface <NUM>.

Embodiments of a bicycle cassette comprise a clampstyle connection for connecting the bicycle cassette to a bicycle hub driver body. The bicycle cassette is attached to a bicycle hub driver body by incorporating a clamp structure into one portion of the cassette, which then rigidly clamps onto the driver body of the bicycle hub. In addition, when combined with a bayonet style attachment structure between two parts of the cassette, it allows for the use of a smaller sprocket on one segment of the cassette. Specifically, it allows a small <NUM> or <NUM> tooth sprocket to overhang the cassette driver body on a bicycle hub, by attaching the small cog assembly to a larger cog assembly using a bayonet style attachment.

In use, the bicycle cassette uses the mechanical advantage of a clamp to reduce the tool force necessary to lock the cassette onto the driver body of a hub. In many traditional cassette assemblies, a large internally or externally threaded fastener is used to clamp an arrangement of different sized sprockets together on a driver body to form a cassette. These fasteners require special tools and high torque to prevent movement and creaking in the cassette assembly. In my invention, a small fastener is all that is necessary to hold the entire cassette assembly stationary on the driver body.

Additionally, the bicycle cassette such as described above, is able to isolate the locking force for the cassette into one region of the assembly, and isolates the driving force from the cassette to the hub in another. The driving force is handled exclusively by a spline feature or other torque transmitting feature, and the axial location and locking of the cassette is managed exclusively by the clamp feature. In this way, each part can be designed to handle exactly the load necessary for proper function of the system.

Further, by minimizing the size of the torque transmitting feature connecting the cassette to the driver body, space is freed up to use smaller sprockets on the small end of the cassette. In many previous cassette assemblies, each one of many sprockets has a spline on its inner surface which connects it to the driver body. In these prior assemblies, a long spline runs the length of driver body, and in fact can limit the size of the smallest sprocket in the cassette, usually to <NUM> teeth. The cassette such as described above, allows the use of a small <NUM> tooth sprocket on the small end of the cassette.

Additionally, different portions of the cassette assembly are able to be manufactured from different materials to allow a balance to be struck between system weight and sprocket strength. For example, the largest sprockets of the cassette assembly may be manufactured from aluminum to save weight and to allow the clamp to function properly, and the smaller sprockets may be manufactured from steel or titanium to decrease wear from the chain in operation.

Further the present invention reduces the number of steps required to assemble a bicycle cassette onto a bicycle hub cassette driver body, by eliminating the need to stack many sprockets onto a splined driver before locking the assembly together with a nut. With the invention, the cassette assembly consists of only two finished assemblies, one clamping fastener and a locking fastener. These parts are keyed so they only fit together one way, which further simplifies the assembly process.

Moreover, installation and/or service is able to be accomplished with simple, commonly available hand tools such as hex keys. Because installation may be accomplished with low tool force, the cassette may be easily serviced even on the road or trail during the course of ride, where previous cassette assemblies require specialized tools which cyclists generally don't carry with them on rides. As such, the bicycle cassette with a clamping connection such as described herein has many advantages.

Claim 1:
A bicycle cassette (<NUM>) comprising:
a. a large sprocket sub-assembly (<NUM>) comprising a clamp screw (<NUM>), a clamping mechanism (<NUM>) for attaching the large sprocket sub-assembly (<NUM>) to a rear bicycle hub (<NUM>), wherein once the large sprocket sub-assembly (<NUM>) is completely engaged on the rear bicycle hub (<NUM>), the large sprocket sub-assembly (<NUM>) clamps to a right-end radial surface (<NUM>) of the rear bicycle hub (<NUM>) by tightening the clamp screw (<NUM>) thereby closing a clamp clearance slot (<NUM>) thereby creating pressure between a clamping surface (<NUM>) and the right-end radial surface (<NUM>); and
b. a small sprocket sub-assembly (<NUM>), wherein the small sprocket sub-assembly (<NUM>) rotatably couples with and locks to the large sprocket sub-assembly (<NUM>) after the large sprocket sub-assembly (<NUM>) is clamped to the rear bicycle hub (<NUM>) to form the bicycle cassette (<NUM>).