Patent Description:
The steering mechanism of a bicycle mainly involves in the rotation of a handlebar coupled with a fork tube and a front wheel to control direction of the bicycle. Structurally, the middle of the handlebar is connected with the top of the fork tube with a stem, the top of the fork tube is mounted through a head tube of a frame, and the two fork tube ends are connected with the central axis of a front wheel.

To keep a rider in balance, the frame is needed to maintain a forward orientation when the fork tube and the front wheel rotate synchronously. Therefore, the fork tube and the head tube rotate relative to each other. A headset is often placed between the head tube and the fork tube to make the rotation smooth.

To achieve smooth and stable rotation of a bicycle, extensive studies on the components of a headset and detailed mechanisms of the components have been done in the industry. For example, the structure of head set disclosed in Taiwan patent application number <CIT> or the improved structure for steering head joint set disclosed in Taiwan patent application number <CIT>.

However, a smooth rotation often leads to over-rotation to affect the balance and to pose a danger to the rider. To improve the safety of the rotation, the industry has started to redesign headsets to avoid over-rotation of the handlebar, the fork tube, and the front wheel. For example, the headset structure with veer limiting function disclosed in Taiwan patent application number <CIT> or the headset assembly capable of limiting steering angle disclosed in Taiwan patent application number <CIT>.

Nevertheless, the conventional limiting structures of a bicycle are often one or more limiting grooves located in some part of an upper cup. This design may cause the center of mass of the upper cup not evenly distributed and affect the smoothness of the rotation of the fork tube and the front wheel during a rotation. Furthermore, the offset of the center of mass of the upper cup may reduce the lifespan of the bearing and causes the bearing to wear out. Serious wear of the bearing may even cause the handlebar to shake and cause the ride unsafe. In addition, most of the bicycle limiting structures are set in the upper headset to cause the force of restraint come from the upper part of the fork tube and to cause the sensitivity, the transmission of the force, and the feedback of the force unsatisfactory due to the long distance between the force of restraint to the front wheel. Moreover, the force of restraint from the upper part of the fork tube is also unstable and affects the maneuverability of the handlebar. Document <CIT> shows the preamble of claim <NUM>.

It is an object of the present invention to provide a bicycle rotation limiting structure that can solve the problem of the center of mass of the upper cup not evenly distributed and extend the lifespan of the headset.

In order to improve the aforementioned problems, the present invention provides a bicycle rotation limiting structure placed in the lower part of a head tube, with a fork tube running through the bicycle rotation limiting structure and the head tube. The bicycle rotation limiting structure comprises: a rotating member installed inside a lower headset cup and encircling the outer part of the fork tube; a positioning set installed inside the lower headset cup and encircling the outer part of the fork tube, wherein said positioning set can make the rotating member positioned inside the lower headset cup and rotate, and said positioning set comprises an inner seat and an outer seat; at least one joining set placed between the fork tube and the positioning set, wherein said joining set anchor the fork tube and the positioning set to provide synchronous and stable rotation; at least one limiting set placed equidistantly between the lower headset cup and the outer seat, wherein the limiting set comprise a limiting groove positioned at the inner rim of the lower headset cup, and a limiting tongue positioned at the outer rim of the outer seat. The limiting groove confines the rotation range of the limiting tongue. The limiting set therefore restricts the synchronous rotation range of the fork tube, the positioning set, and the rotating member. With the joining set located between the positioning set and the middle part of the fork tube and with the limiting set located between the lower headset and the middle part of the fork tube, the force of restraint and the synchronous rotation force are coming from the middle part of the fork tube, and the forces are transmitted to the two ends of the fork tube, shortening the transmission time and improving the maneuverability of rotation. Two or more of the limiting sets surround equidistantly between the lower headset cup and the outer seat, making the center of mass located in the center of the rotation axes during rotation, improving the stability of the rotation, reducing the wear and tear of the bearing thus increasing the lifespan of the bicycle, and enhancing safety of the bicycle.

As above description, the present invention has beneficial effects and advantages as following:.

Many of the attendant features and advantages of the present invention will become better understood with reference to the following detailed description considered in connection with the accompanying figures and drawings.

The steps and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings.

Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts. It is not intended to limit the method by the exemplary embodiments described herein. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to attain a thorough understanding of the disclosed embodiments. As used in the description herein and throughout the claims that follow, the meaning of "a", "an", and "the" may include reference to the plural unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the terms "comprise or comprising", "include or including", "have or having", "contain or containing" and the like are to be understood to be open-ended, i.e., to mean including but not limited to.

With reference to <FIG>, a preferred embodiment of a bicycle rotation limiting structure is positioned in the lower part of a head tube <NUM>, and the bicycle rotation limiting structure is mounted around a fork tube <NUM>. The bicycle rotation limiting structure comprises a lower headset cup <NUM> and a rotating member <NUM>, a positioning set <NUM>, a joining set <NUM>, and two limiting set <NUM> installed inside the lower headset cup <NUM>.

The lower headset cup <NUM> is placed in the inner wall of the lower part of the head tube <NUM>. An upper headset <NUM> is placed in the inner wall of the upper part of the head tube <NUM>, and the upper headset <NUM> is mounted around the fork tube <NUM>. The fork tube <NUM> comprises a fork crown <NUM> and a steering tube <NUM> extending through the center part of the fork crown <NUM>, and a base <NUM> is mounted on the junction of the fork crown <NUM> and the steering tube <NUM>.

The rotating member <NUM> comprises an inner surface and an outer surface, and the lower headset cup <NUM> is attached to the inner surface of the rotating member <NUM>, and a positioning set <NUM> is attached to the outer surface of the rotating member <NUM>. The rotating member <NUM> is placed in the lower headset cup <NUM> and the rotating member <NUM> is mounted the fork tube <NUM>. The rotating member <NUM> and the fork tube <NUM> can rotate smoothly and synchronously in the head tube <NUM>.

The positioning set <NUM> is placed in the lower headset cup <NUM>, and the positioning set <NUM> is mounted around the fork tube <NUM>. The positioning set <NUM> confines the rotating member <NUM> to rotate inside the lower headset cup <NUM>. The positioning set <NUM> comprises an inner seat <NUM> and an outer seat <NUM>. The inner seat <NUM> and the outer seat <NUM> are ring-shaped and coupled together. A contact surface <NUM> is defined at one side of the inner seat <NUM> and is in contact with the inner surface of the rotating member <NUM>. The outer part of the outer seat <NUM> is attached to the inner part of the lower headset cup <NUM>. An inner split <NUM> is formed in the inner seat <NUM> and an outer split <NUM> is defined in the outer seat <NUM>. At least one snap-fit pair <NUM> is mounted between the inner seat <NUM> and the outer seat <NUM>. The snap-fit pair <NUM> is a pair of interlocking components locks the inner seat <NUM> and outer seat <NUM> and makes the inner seat <NUM> and the outer seat <NUM> rotate synchronously. The snap-fit pair <NUM> comprises a slot <NUM> defined in the outer rim of the inner seat <NUM> and a protrusion <NUM> corresponds to the slots <NUM> and is formed on the inner rim of the outer seat <NUM>.

The joining set <NUM> is located between the fork tube <NUM> and the positioning set <NUM>. The joining set <NUM> combine the fork tube <NUM> with the positioning set <NUM> together and makes the fork tube <NUM> and the positioning set <NUM> rotate synchronously. The joining set <NUM> comprises a first joining member <NUM>. The first joining member <NUM> is a raised area located on the outer seat <NUM>. The joining set <NUM> also comprises a second joining member <NUM>. The second joining member <NUM> is an indentation on the base <NUM> of the fork tube <NUM>, and the second joining member <NUM> is aligned with the direction of the axis of the fork tube and corresponds to the first joining member <NUM> in position.

Two limiting sets <NUM> are located between the lower headset cup <NUM> and the outer seat <NUM> and are arranged annularly and equidistantly. Each limiting set <NUM> comprises a limiting groove <NUM>, wherein the limiting groove <NUM> is a trench defined in the inner rim of the lower headset cup <NUM>. The limiting set <NUM> also comprises a limiting tongue <NUM>, wherein the limiting tongue <NUM> is a protrusion formed on the outer rim of the outer seat <NUM> and the limiting tongue <NUM> is confined to rotate within the range of the limiting groove <NUM>. The limiting set <NUM> can effectively limit the rotation range of the synchronous rotation of the fork tube <NUM>, the positioning set <NUM>, and the rotating member <NUM> whether the rotation is clockwise or counterclockwise.

With the abovementioned parts and components, the joining set <NUM> is placed between the positioning set <NUM> and the middle part of the fork tube <NUM>, and the two limiting sets <NUM> are place in the lower headset cup <NUM> near the middle part of the fork tube <NUM> to make the force of restraint and the synchronous rotation force come from the middle part of the fork tube <NUM>. The forces are transmitted to the two ends of the fork tube <NUM> to shorten the transmission time and to improve the maneuverability of rotation. Two or more the limiting sets <NUM> may be arranged annularly and equidistantly between the lower headset cup <NUM> and the outer seat <NUM> to make the center of mass located at the center of the rotation axes during rotation, such that the stability of the rotation can be improved to reduce the wear and tear of the bearing, accordingly, the lifespan of the bicycle is prolonged, and safety of the bicycle is enahced.

To further elaborate the details of the embodiment, the usage of the present invention is described as follows:.

The installation of this invention. First, the inner seat <NUM> is mounted inside the outer seat <NUM> to make the slots <NUM> and the protrusions <NUM> engage with each other mutually. Then, the rotating member <NUM> and the positioning set <NUM> are placed inside the lower headset cup <NUM>. The contact surface <NUM> is in contact with the inner surface of the rotating member <NUM>, and the limiting tongue <NUM> is held within the limiting groove <NUM>. Then, the steering tube <NUM> of the fork tube <NUM> is mounted through the lower headset cup <NUM>, the rotating member <NUM>, the positioning set <NUM>, the head tube <NUM>, and the upper headset <NUM> sequentially and a cap is installed on the upper headset <NUM> and fork tube <NUM> to fasten and finish the installation.

With reference to <FIG>, when the handlebar is facing forward during a ride, the limiting tongue <NUM> is at the middle part of the limiting groove <NUM>. With reference to <FIG>, when the handlebar is turned left during a ride, the lower headset cup <NUM> and the head tube <NUM> continue to maintain the same direction, and the fork tube <NUM>, the rotating member <NUM> and the positioning set <NUM> synchronously rotate counterclockwisely. At the same time, the limiting tongue <NUM> also rotate counterclockwisely within the limiting groove <NUM> until the limiting tongue <NUM> touches the end of the limiting groove <NUM> and stop moving.

With reference to <FIG>, when the handlebar is turned right during a ride, the lower headset cup <NUM> and the head tube <NUM> continue to maintain the same direction, and the fork tube <NUM>, the rotating member <NUM> and the positioning set <NUM> synchronously rotate clockwisely. At the same time, the limiting tongue <NUM> also rotate clockwisely within the limiting groove <NUM> until the limiting tongue <NUM> touches the end of the limiting groove <NUM> and stop moving.

Since the limiting set <NUM> is located inside the lower headset cup <NUM>, when the limiting tongue <NUM> touches the end of the limiting groove <NUM>, a restraining force is generated and transmitted to the middle part of the fork tube <NUM>, limiting further rotation of the fork tube <NUM>, the rotating member <NUM>, and the positioning set <NUM>. The lower headset cup <NUM> is located around the middle part of the fork tube <NUM> (close to the base <NUM> of the fork tube <NUM>), and thus the restraining force is transmitted synchronously to the handlebar and the front wheel, and the rider feels the restraint and cannot continue to rotate the handlebar.

When changing direction of the handlebar, the rider turns the handlebar and drives the fork tube <NUM>, the rotating member <NUM>, and the positioning set <NUM> to rotate synchronously. Therefore, the driving force of rotation comes from the connection part of the upper fork tube <NUM> and the handlebar. Then, the driving force is transmitted from the upper part of the fork tube <NUM> to the rotating member <NUM> and the positioning set <NUM>. The joining set <NUM> increases the transmission area of the driving force. At the same time, the first joining member <NUM> and the second joining member <NUM> attach mutually to make the connection of the fork tube <NUM> and the positioning set <NUM> stable and to increase the synchronicity of the rotation. Furthermore, the joining set <NUM> is located between the positioning set <NUM> and the base <NUM> to add an additional driving force from the middle part of the fork tube <NUM> and transmitted to the upper part and lower part of the fork tube <NUM> so as to improve the maneuverability of the rider.

The inner split <NUM> and the outer split <NUM> provide elasticity and flexibility for the inner seat <NUM> and outer seat <NUM> to adapt different precisions and sizes of related components of a bicycle. The inner seat <NUM> and the outer seat <NUM> can be installed easily and grip the fork tube <NUM> tightly due to the elasticity. The inner seat <NUM> and the outer seat <NUM> can be coupled with aligning the inner split <NUM> with the outer split <NUM> or without aligning the inner split <NUM> with the outer split <NUM>.

The first joining member <NUM> can be integrally formed on the outer seat <NUM>, and the second joining member <NUM> can be integrally formed on the fork tube <NUM>. Therefore, the fork tube <NUM> and the second joining member <NUM> are made of a same first material with identical hardness. The outer seat <NUM> and the first joining member <NUM> are also made of a same second material with identical hardness.

With reference to <FIG> and <FIG>, in a second preferred embodiment, the joining set <NUM> further comprises a protective component <NUM> placed between the first joining member <NUM> and the second joining member <NUM>. The protective component <NUM> fully covers the first joining member <NUM> or fully covers the second joining member <NUM>. The hardness of the protective component <NUM> may be same as the hardness of the first joining member <NUM> or the second joining member <NUM>. The hardness of the protective component <NUM> may also be different from the hardness of the first joining member <NUM> or the second joining member <NUM>.

If the hardness of the protective component <NUM> is lower than the hardness of the first joining member <NUM> and the second joining member <NUM>, the protective component <NUM> effectively reduces the wear and tear of the first joining member <NUM> and the second joining member <NUM>.

With reference to <FIG>, in a third preferred embodiment, the first joining member <NUM> is an indentation located on the outer seat <NUM>, and the second joining member <NUM> is a raised area located on the base <NUM> of the fork tube <NUM> and corresponds to the first joining member <NUM>. In addition, at least one snap-fit pair <NUM> is formed on the inner seat <NUM> and the outer seat <NUM>. The snap-fit pair <NUM> comprises a protrusion <NUM> on the outer rim of the inner seat <NUM> and a slot <NUM> corresponds to the protrusion <NUM> on the inner rim of the outer seat <NUM>.

With reference to <FIG>, in a fourth preferred embodiment, a limiting set <NUM> is located between the lower headset cup <NUM> and the outer seat <NUM>. The limiting set <NUM> comprises a limiting groove <NUM>, wherein the limiting groove <NUM> is a trench defined in the inner rim of the lower headset cup <NUM>. The limiting set <NUM> also comprises a limiting tongue <NUM>, wherein the limiting tongue <NUM> is a protrusion formed on the outer rim of the outer seat <NUM> and the limiting tongue <NUM> is confined to rotate within the range of the limiting groove <NUM>. The limiting set <NUM> can effectively limit the rotation range of the synchronous rotation of the fork tube <NUM>, the positioning set <NUM>, and the rotating member <NUM> whether the rotation is clockwise or counterclockwise.

The limiting set <NUM> of this embodiment is placed in the lower headset cup <NUM> near the middle part of the fork tube <NUM> to make the force of restraint come from the middle part of the fork tube <NUM>, and the forces are transmitted to the two ends of the fork tube <NUM> to shorten the transmission time and to improve the maneuverability of rotation.

In conclusion, the bicycle rotation limiting structure of this invention can effectively reduce the transmission time of forces, improve the maneuverability and stability of a bicycle, and also reduce the wear and tear of bearings and thus enhance the safety of the bicycle. The joining set located between the positioning set and the middle part of the fork tube along with the limiting set located in the lower headset cup around the middle part of the fork tube make the force of restraint and the synchronous rotation force come from the middle-part of the fork tube to improve the riding experience and safety of a bicycle.

Claim 1:
A bicycle rotation limiting structure, comprising a lower headset, wherein the lower headset comprises a lower headset cup (<NUM>), a rotating member (<NUM>), and a positioning set (<NUM>), wherein,
the rotating member (<NUM>) comprises an inner surface and an outer surface, wherein the outer surface rotates freely upon the inner surface;
the lower headset cup (<NUM>) is attached to the inner surface and the positioning set (<NUM>) is attached to outer surface, wherein the lower headset cup (<NUM>) can rotate relatively to the positioning set (<NUM>), and the lower headset cup (<NUM>) overlaps partially with the positioning set (<NUM>) and forms an overlapping part, wherein a limiting groove (<NUM>) and a limiting tongue (<NUM>) are formed at the overlapping part, and the limiting tongue (<NUM>) can move within the limiting groove (<NUM>); and
characterized in that the positioning set (<NUM>) comprises:
an inner seat (<NUM>) and an outer seat (<NUM>), wherein the inner seat (<NUM>) and the outer seat (<NUM>) are ring-shaped and coupled together, wherein a contact surface (<NUM>) is defined at one side of the inner seat (<NUM>) and the contact surface (<NUM>) is in contact with the inner surface of the rotating member (<NUM>), and the outer seat (<NUM>) is attached to the lower headset cup (<NUM>).