Patent Description:
The technology of interior derailleurs of bicycles is known in the art and used commonly. Many different technologies provide different speed change ratios based different technical theories. However, these differences affect the structures and effects of the bicycles. Furthermore, there are many new designs which provide useful effects, but they still have defects in use. Therefore they are not practical due to the defects in applications.

For multiple stage speed change designs which are variable based on the users. For example, sporters like multiple stage speed change design with many speed change stages, while people used in daily life likes speed change of just few stages, generally, it has three or four change stages. Therefore, fewer change stage design has wide markets and are acceptable widely, and also suitable under consideration of economics. In general, three or fourth speed changes are widely used.

However, for derailleurs with fewer speed change stages, they have a defect of temporarily jump in change of gears which causes the unsmooth in driving bicycles. For a fourth speed change design, only fewer layer (two layers) planet gear speed change system is used. When changing from <NUM> stage to three stage, the closing of the axial ratchet in the first planet gear speed change system for control the sun gear to be fixed or freely rotating is operated along an inverse direction, as a result, in operation, a great torque is needed. Furthermore, in mechanical structure, the axial ratchet of the first planet gear speed change system close firstly, while the axial ratchet of the second planet gear speed change system does not open, the speed auto-changes to the first speed and then to the third speed. Or the axial ratchet of the first planet gear speed change system does not close firstly, while the axial ratchet of the second planet gear speed change system has opened, the speed auto-changes to the fourth speed and then to the first speed. However, these phenomenon will induce the temporary speed jump and thus the operation is not smooth. <CIT> discusses a multi-speed hub gear, in particular for a cycle, and discloses a gear switching control device of an internal derailleur according to the preamble of claim <NUM>.

Accordingly, the object of the present invention is to provide a gear switching control device of an internal derailleur, advantages of the present invention are that:
The present invention could resolve the problem induced from the gear change of internal derailleurs of two layer planet gear speed change system.

The present invention has a simple structure, lower torque, and lower power which is novel, practical and progressive.

Each layer of the planet gear speed change system has identical speed change ratio and as a result, and thus they have same module structure. The cost is reduced effectively and the manufacturing steps are simplified.

To achieve above object, in accordance with the present invention, there is provided a gear switching control device of an internal derailleur as recited by claim <NUM>. Preferred features are set out in the dependent claims.

By the rotation of the track sleeve of the gear switching control unit, each ratchet control ring controls the axial ratchet switch of a respective planet gear speed change system so as to affectively resolve the speed delay in gear change period of a prior art bicycle derailleur having two layers of planet gear speed change systems. Furthermore, controlling of gear switching is simplified, light torque with less power.

In order that those skilled in the art can further understand the present invention, a description will be provided in the following in details. However, these descriptions and the appended drawings are only used to cause those skilled in the art to understand the objects, features, and characteristics of the present invention, but not to be used to confine the scope of the present invention defined in the appended claims.

As illustrated in <FIG>, an embodiment of embodiment is illustrated. In this embodiment, a three layer planet gear speed change system is used for description of the present invention. However, the present invention can be realized in a planet gear speed change system over three layers.

With reference to <FIG>, a derailleur of the present invention includes a plurality of layers of planet gear speed change system. The present invention includes the following elements: a wheel axis <NUM>, a track sleeve <NUM>, sun gears <NUM>, planet frames <NUM>, washers <NUM>, two layered planet gear <NUM>, pins <NUM>, ratchets <NUM>, claw springs <NUM>, right toggles <NUM>, pads <NUM>, position rings <NUM>, washers <NUM>, left toggles <NUM>, inner teeth <NUM>, outer casing interior teeth <NUM>, axial ratchets <NUM>, springs <NUM>, positioning springs <NUM>, buckling rings <NUM>, a first ratchet control ring <NUM>, a second ratchet control ring <NUM>, a third ratchet control ring <NUM>, input base <NUM>, a large bearing <NUM>, a small bearing <NUM>, a small bearing seat <NUM>, a chain disk <NUM>, a control plate <NUM>, a sleeve <NUM>, a net <NUM>, a casing <NUM>, a distal bearing seat <NUM>, a dust proof cover <NUM>, and a chain disk positioning spring <NUM>.

The interior of the interior derailleur has a first, a second and a third planet gear speed change systems. Each planet gear speed change system has same speed ratio so that they have identical modular structures as illustrated in <FIG> and <FIG>. As a result, the cost in develop and manufacturing is reduced greatly and the assembly work is simplified.

Between a sun gear <NUM> of each planet gear speed change system and a wheel axis <NUM> of an interior derailleur is installed with an axial ratchet <NUM> for controlling separation and combination of the sun gear <NUM> and the axis <NUM>. A spring <NUM> is installed between the axial ratchet <NUM> and the wheel shaft <NUM> so that the axial ratchet <NUM> are adhered to cams of the first ratchet control ring <NUM>, the second ratchet control ring <NUM> and the third ratchet control ring <NUM>, as illustrated in <FIG>.

With reference to <FIG>, all the axial ratchets <NUM> are controlled by a gear switch control device as illustrated in <FIG>. The gear switch control device includes a track sleeve and the first axial ratchet control ring <NUM> (referring to <FIG>), the second axial ratchet control ring <NUM> (referring to <FIG>) and third axial ratchet control ring <NUM> (referring to <FIG>) which are all serial connected to the same track sleeve <NUM>. Referring to <FIG>, one end of the track sleeve <NUM> has an external action portion 2a which is movable by external forces and another end thereof is installed with a linking rod 2b which serially connect all the axial ratchet control rings <NUM>, <NUM> and <NUM>.

Each of the axial ratchet control rings <NUM>, <NUM> and <NUM> are formed with respective connecting holes 21a, 22a and 23a for receiving the track sleeve <NUM>. Each of the first axial ratchet control ring <NUM>, the second axial ratchet control ring <NUM> and the third axial ratchet control ring <NUM> is installed with a cam (or cam like device). These cams includes respective first, second and third derailleur closing surfaces 21b, 22b, and 23b and respective first, second and third derailleuring opening surfaces 21c, 22c, and 23c for derailleuring the axial ratchet <NUM> between the wheel axis <NUM> and respective sun gear <NUM>. Movable radial ranges of the respective first, second and third derailleur closing surfaces 21b, 22b, and 23b are different from each other, and movable radial ranges of the respective first, second and third derailleur opening surfaces 21c, 22c, and 23c are different from each other.

With reference to <FIG>, it shows derailleuring states of the axial ratchets <NUM> between the wheel axis <NUM> and the sun gear <NUM> based on the structure relations for the first axial ratchet control ring <NUM>, second axial ratchet control ring <NUM> and third axial ratchet control ring <NUM> in three different derailleuring positions from the first to fourth derailleuring positions.

<FIG> shows the first derailleuring position, in that the track sleeve <NUM> does not act. The axial ratchet <NUM> of the first planet gear speed change system is in the radial range of the derailleur closing surface 21b of the first axial ratchet control ring <NUM>. Therefore the axial ratchet <NUM> of the first planet gear speed change system causes the sun gear <NUM> of the first planet gear speed change system is in a free state without being fixed. The axial ratchet <NUM> of the first planet gear speed change system is in the radial range of the derailleur closing surface 21b of the first axial ratchet control ring <NUM>. Therefore the axial ratchet <NUM> causes the sun gear <NUM> of the first planet gear speed change system is in a free state without being fixed. The axial ratchet <NUM> of the second planet gear speed change system is in the radial range of the derailleur closing surface 22b of the second axial ratchet control ring <NUM>. Therefore the axial ratchet <NUM> of the second planet gear speed change system causes the sun gear <NUM> of the second planet gear speed change system is in a free state without being fixed. The axial ratchet <NUM> of the third planet gear speed change system is in the radial range of the derailleur closing surface 23b of the third axial ratchet control ring <NUM>. Therefore the axial ratchet <NUM> of the third planet gear speed change system causes the sun gear <NUM> of the third planet gear speed change system is in a free state without being fixed. That is, all the sun gears <NUM> are in free rotation state without being fixed. At this moment, speed ratio is <NUM>.

<FIG> shows that the second derailleuring position, in that, the track sleeve <NUM> is in a second gear position as it is switched from a first gear position to the second gear position, the axial ratchet <NUM> of the first planet gear speed change system is in the in the radial range of the derailleur opening surface 21c of the first axial ratchet control ring <NUM>, as a result, the axial ratchet <NUM> of the first planet gear speed change system causes that the sun gear <NUM> of the first planet gear speed change system is fixed. The axial ratchet <NUM> of the second planet gear speed change system is within the radial range of the derailleur closing surface 22b of the second axial ratchet control ring <NUM> so that the axial ratchet <NUM> of the second planet gear speed change system causes that the sun gear <NUM> of the second planet gear speed change system is in a free rotating state. The axial ratchet <NUM> of the third planet gear speed change system is within the radial range of the derailleur closing surface 23b of the third axial ratchet control ring <NUM>, as a result, the axial ratchet <NUM> of the third planet gear speed change system causes the sun gear <NUM> of the third planet gear speed change system is in a free rotating state. At this moment, the axial ratchet <NUM> of the first planet gear speed change system is in a derailleur opening state, that is, the sun gear <NUM> of the first planet gear speed change system is fixed, while the axial ratchets <NUM> of the second and third planet gear speed change systems are in derailleur closing state, that is, the sun gears of the second and third planet gear speed change systems are in a free rotation state, and the speed ratio of a.

<FIG> shows that the track sleeve <NUM> of the gear switching control structure is switched from second gear position to third gear position. In the third gear position, the axial ratchets <NUM> of the first and second planet gear speed change system is within a radial range of the derailleur opening surface 21c of the first axial ratchet control ring <NUM> so that the axial ratchets <NUM> of the first and second planet gear speed change system causes that the sun gears <NUM> of the first and second planet gear speed change system are fixed. The axial ratchet <NUM> of the third planet gear speed change system is positioned within the radial range of the derailleur closing surface 23b of the third axial ratchet control ring <NUM> so that axial ratchet <NUM> of the third planet gear speed change system causes that the sun gear <NUM> of the third planet gear speed change system is still in a free rotation state. At this time, the axial ratchets <NUM> of the first and second planet gear speed change system is in a derailleur opening state, that is, the sun gear <NUM> is in a fixed state, while the axial ratchet <NUM> of the third planet gear speed change system is in a derailleur closing state and the sun gear <NUM> thereof is in a free rotation state. At this moment, the speed ratio is square a (a to the power of <NUM>).

<FIG> shows that the track sleeve <NUM> of the gear switching control structure is switched from third gear position to fourth gear position. In the fourth gear position, the axial ratchets <NUM> of the first planet gear speed change system is positioned in a radial range of the derailleur opening surface 21c of the first axial ratchet control ring <NUM>, thereby, the axial ratchet <NUM> of the first planet gear speed change system causes the sun gear <NUM> of the first planet gear speed change system is in a fixed state. The axial ratchet <NUM> of the second planet gear speed change system is positioned in a radial range of the derailleur opening surface 22c of the second axial ratchet control ring so that the axial ratchet <NUM> of the second planet gear speed change system causes that the sun gear <NUM> of the second planet gear speed change system is in a fixed state. The axial ratchet <NUM> of the third planet gear speed change system is positioned in the radial range of the derailleur opening surface 23c of the third axial ratchet control ring, as a result, the axial ratchet <NUM> of the third planet gear speed change system causes that the sun gear <NUM> of the third planet gear speed change system is in a fixed state. At this moment, the axial ratchets <NUM> of the first to third planet gear speed change system are in a derailleur opening state. That is, all the sun gears <NUM> are in a fixed state. Now, the speed ratio is a to the power of <NUM>.

The <FIG> show the operation from a low gear level to a high gear level and show the gear variations of the axial ratchets <NUM> of various planet gear speed change systems. However, it is desired to have the result of high gear level to low gear level, the sequence is those from <FIG> along a reverse order.

Advantages of the present invention are that: the present invention could resolve the problem induced from the gear change of internal derailleurs of two layer planet gear speed change system. The present invention has a simple structure, lower torque, and lower power which is novel, practical and progressive. Each layer of the planet gear speed change system has identical speed change ratio and as a result, and thus they have same module structure. The cost is reduced effectively and the manufacturing steps are simplified. The present invention is useful and economic.

Claim 1:
A gear switching control device of an internal derailleur, said internal derailleur comprising:
a plurality of planet gear speed change systems; said gear switching control device comprising:
a gear switching control unit; a plurality of axial ratchets (<NUM>);
a plurality of axial ratchet control rings (<NUM>, <NUM> and <NUM>) for controlling the action of said plurality of axial ratchets;
wherein the number of the plurality of axial ratchet control rings is identical to the number of the plurality of planet gear speed change systems; wherein the number of the plurality of axial ratchets is identical to the number of the plurality of axial ratchet control rings; and wherein the plurality of axial ratchet control rings are serially connected by the same gear switching control unit;
characterized in that
the gear switching control unit comprises: a track sleeve (<NUM>), wherein one end of the track sleeve (<NUM>) is installed with a force accept portion (2a) that is movable by external forces, and another end thereof is installed with a linking rod (2b) which serially connects the plurality of axial ratchet control rings (<NUM>, <NUM> and <NUM>); and
wherein each of the axial ratchet control rings (<NUM>, <NUM> and <NUM>) is formed with respective connecting holes (21a, 22a and 23a) for receiving the track sleeve (<NUM>); wherein each axial ratchet control ring (<NUM>, <NUM> and <NUM>) is installed with a cam or cam-like device; and wherein the cams or cam-like devices have different operating moving ranges.