Description A BICYCLE

Technical Field

[1] The present invention relates to a bicycle.

Background Art

[2] The present invention relates, in general, to bicycles and, more particularly, to a bicycle which is constructed such that, even when a driver increases pedaling force to accelerate the bicycle, variation in the center of gravity of the driver and the bicycle can be minimized, thus enhancing the traveling stability of the bicycle.

[3] Generally, in bicycles, a pedal gear, which receives driving force from pedals, is disposed adjacent to one pedal, so that, when a driver pushes the pedals, asymmetrical force is applied to the bicycle.

[4] Therefore, as shown in Fig Ia, in a state in which no force is applied to the pedals P, the driver aligns the line B of the center of gravity of his/her body with the line C of the center of gravity of the bicycle and thus is able to easily maintain the line A of the center of gravity of the body together with the bicycle at a contact point D between the bicycle and the ground.

[5] However, as shown in Fig. Ib, when the driver applies a force F to one pedal P to accelerate the bicycle, due to the pedal gear G disposed at the eccentric position, eccentric force is applied to the bicycle at a position offset by the distance between the line C of the center of gravity of the bicycle and a point E, at which the driver applies the force to the pedal, that is, eccentric force is applied to the bicycle. Therefore, the center of gravity of the driver's body is moved to the right at an angle of θl, and the bicycle is tilted to the left, that is, in the opposite direction, at an angle of θ2 corresponding to θ 1 with respect to the line A of the center of gravity of the body and the bicycle on the contact point D, thus keeping the balance.

[6] As such, in the case of the conventional bicycle, the driver must repeatedly tilt the bicycle to the left and right to maintain balance when accelerating the bicycle, so that the steering ability is deteriorated, and it is difficult to ensure traveling stability when the bicycle is accelerated.

Disclosure of Invention

Technical Problem

[7] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a bicycle which reduces lateral movement thereof when traveling, thus making it possible to stably travel even when it is accelerated rapidly.

[8] Other objects and advantages of the present invention will be explained later herein and will be appreciated by examining the following embodiment.

[9] Furthermore, the objects and advantages of the present invention can be realized by the means disclosed in the accompanying claims and combinations of the means in the claims.

Advantageous Effects

[10] In the bicycle according to the present invention, a pedal gear, a first acceleration gear, a second acceleration gear, a third acceleration gear and a wheel gear are disposed at a center with reference to the lateral direction of a main body frame of the bicycle, so that, even when pedals are rotated, the bicycle can maintain the balance, that is, it is prevented from being asymmetrical, thus making it possible for a driver to stably accelerate the bicycle.

[11] Although the preferred embodiment of the present invention is disclosed for illustrative purposes with reference to the attached drawings, the present invention is not limited to this. Furthermore, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Brief Description of the Drawings

[12] Figs. 1 and 2 are views illustrating a state of a conventional bicycle when traveling;

[13] Fig. 3 is a view illustrating a bicycle, according to an embodiment of the present invention;

[14] Fig. 4 is a partial enlarged view of Fig. 3;

[15] Fig. 5 is a schematic view showing the construction of Fig. 4;

[16] Fig. 6 is a schematic view showing the construction of Fig. 4 according to another embodiment of the present invention;

[17] Fig. 7 is a perspective view of a main body frame of Fig. 3;

[18] Fig. 8 is a perspective view showing a wind screen of Fig. 3; and

[19] Fig. 9 is a sectional view taken along the line A-A of Fig. 8.

[20] * Description of the elements in the drawings*

[21] 1: bicycle 10: main body frame

[22] 11: wheel 12: handle

[23] 13: seat 14: pedals

[24] 20: pedal gear 30: first acceleration gear

[25] 40: second acceleration gear 50: third acceleration gear

[26] 70: first chain 70: wheel gear

[27] 80: second chain 90: wind screen

[28] 91: front plate 92: subsidiary plate

[29] 100: gear cover 110: chain wheel

Best Mode for Carrying Out the Invention

[30] In order to accomplish the above object, the present invention provides a bicycle, including: a main body frame for supporting front and rear wheels, the main body frame having a handle for steering, a seat for supporting a driver in a seating position, and a pair of pedals connected to the rear wheel so that drive force is generated by rotating the pair of pedals; a pedal gear, having a chain wheel provided on a medial portion of a shaft, connecting the pedals to each other, the chain wheel being rotated along with the shaft by rotation of the pedals at a same rpm as an rpm of the pedals; a first acceleration gear provided in the main body frame and having a pair of chain wheels, diameters of which are equal to each other and are less than a diameter of the chain wheel of the pedal gear, the first acceleration gear engaging with the pedal gear and increasing an rpm transmitted from the pedal gear; a second acceleration gear provided in the main body frame and including a chain wheel having a diameter less than the diameter of the chain wheel of the first acceleration gear, the second acceleration gear engaging with the first acceleration gear and increasing an rpm transmitted from the first acceleration gear; a third acceleration gear provided in the main body frame and having a pair of chain wheels, diameters of which are equal to each other and are less than the diameter of the chain wheel of the second acceleration gear, the third acceleration gear increasing an rpm transmitted from the pedal gear; a first chain for connecting the second acceleration gear to the third acceleration gear; a wheel gear having an H-shaped symmetric structure such that a plurality of chain wheels, which have different diameters to form a power transmission structure having more than one stage, is provided on each of opposite ends of the wheel gear, the wheel gear receiving the increased rpm from the third acceleration gear and rotating the rear wheel; and a second chain for connecting the third acceleration gear to the wheel gear. Here, part of the main body frame to which the pedal gear, the first acceleration gear, the second acceleration gear, the third acceleration gear and the wheel gear are coupled has a fork frame structure such that the gears are disposed at a center with respect to a lateral direction of the main body frame.

[31] Hereinafter, a preferred embodiment of the present invention will be described with reference to the attached drawings.

[32] The terms and words used in the specification and claims must not be limited to typical or dictionary means, but must be regarded as concepts selected by the inventor as the best method of illustrating the present invention, and must be interpreted as having meanings and concepts adapted to the scope and sprit of the present invention for understanding the technology of the present invention.

[33] Therefore, the construction of the embodiment illustrated in the specification and the drawings must be regarded as only one illustrative example which is not intended to limit the present invention. Furthermore, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention.

[34] Fig. 3 is a view illustrating a bicycle, according to the preferred embodiment of the present invention. Fig. 4 is a partial enlarged view of Fig. 3. Fig. 5 is a plan view of Fig. 3.

[35] As shown in the drawings, a bicycle 1 according to the preferred embodiment of the present invention includes a main body frame 10, a pedal gear 20, a first acceleration gear 30, a second acceleration gear 40, a third acceleration gear 50, a first chain 60, a wheel gear 70 and a second chain 80.

[36] The main body frame 10 supports a driver thereon and rotatably supports wheels

11, which are provided on respective front and rear ends thereof.

[37] Furthermore, a handle 12, which makes it possible for the driver to steer the bicycle, and a seat 13, which supports the driver in a sitting position, are provided on the main body frame 10.

[38] In addition, a pair of pedals 14, which is connected to the rear wheel 11, is provided on the main body frame 10 to generate drive force using rotation thereof.

[39] Here, as shown in Fig. 7, the main body frame 10 preferably has a bifurcate structure such that the pedal gear 20, the first acceleration gear 30, the second acceleration gear 40, the third acceleration gear 50 and the wheel gear 70 are disposed at the center with respect to the lateral direction of the main body frame 10.

[40] That is, the pedal gear 20, the first acceleration gear 30, the second acceleration gear 40, the third acceleration gear 50 and the wheel gear 70 are provided between the two fork parts of the main body frame 10, so that the bicycle is prevented from being biased in one lateral direction, thus enhancing the traveling stability of the bicycle.

[41] Meanwhile, a wind screen 90 may be provided on the main body frame 10 around the handle 12 to prevent the driver from being impacted by wind or foreign substances such as dust when traveling.

[42] As shown in Figs. 8 and 9, the wind screen 90 includes a front plate 91, which is bent at a medial portion thereof, and a plurality of subsidiary plates 92, which are sequentially coupled to each of the opposite ends of the front plate 91 such that the plates are spaced apart from each other at regular intervals.

[43] It is preferable that the wind screen 90 be made of transparent material to allow the driver to readily observe the surroundings ahead.

[44] In the wind screen 90 having the above-mentioned construction, the front plate 91 and the subsidiary plates 92 form a streamlined shape, so that wind can smoothly flow

around the bicycle rearwards when the bicycle travels. Furthermore, even if wind blows forwards, that is, if there is a tailwind, wind can flow out of the wind screen through gaps defined between the front plate and the subsidiary plates 92, which are spaced apart from each other. Therefore, the influence of wind on the bicycle when traveling can be minimized.

[45] In the present invention, a gear cover 100 may be provided at a corresponding position on the main body frame 10 to cover the pedal gear 20, the first acceleration gear 30, the second acceleration gear 40 and the third acceleration gear 50, such that they are not exposed outside, thus preventing foreign substance from being trapped between the gears.

[46] The pedal gear 20 is fitted over a shaft, which connects the pedals 14 to each other, and has thereon a chain wheel 110, which rotates at the same rpm as the pedals 14.

[47] In detail, the pedal gear 20 is coupled to the center of the shaft, connecting the pedals 14 to each other, such that the shaft is prevented from being eccentric.

[48] Furthermore, as shown in Fig. 6, the pedal gear 20 may have a pair of chain wheels

110, which have the same diameter.

[49] In this case, even though the bicycle is tilted in one direction, the chain wheels 110, which are disposed on the respective opposite ends of the pedal gear 20, compensate for the displacement of the center of gravity of the bicycle, thus promoting traveling stability.

[50] The first acceleration gear 30 engages with the pedal gear 20 so that rotating force is transmitted from the pedal gear 20 to the first acceleration gear 30.

[51] The first acceleration gear 30 is an H-shaped gear, which includes a pair of chain wheels 110, the diameters of which are equal to each other and are smaller than the diameter of the chain wheel 110 of the pedal gear 20. The first acceleration gear 30 is rotatably provided between the two fork parts of the main body frame 10.

[52] Therefore, the first acceleration gear 30 is rotated using the rotating force transmitted from the pedal gear 20 at an increased rpm compared to that of the pedal gear 20.

[53] The second acceleration gear 40 engages with the first acceleration gear 30 to receive rotating force from the first acceleration gear 30.

[54] The second acceleration gear 40 includes a chain wheel having a diameter smaller than that of the chain wheel 110 of the first acceleration gear 30. The second acceleration gear 40 is rotatably provided at a position adjacent to the first acceleration gear 30 between the two fork parts of the main body frame 10.

[55] Therefore, the second acceleration gear 40 is rotated using the rotating force transmitted from the first acceleration gear 30 at an increased rpm, compared to that of the first acceleration gear 30.

[56] The third acceleration gear 50 engages with the second acceleration gear 40 to receive rotating force from the second acceleration gear 40.

[57] The third acceleration gear 50 is an H-shaped gear, which includes a pair of chain wheels 110, the diameters of which are equal to each other and are smaller than the diameter of the chain wheel 110 of the second acceleration gear 40. The third acceleration gear 50 is rotatably provided between vertical two fork parts of the main body frame 10, which are below the seat 13 of the bicycle.

[58] Therefore, the third acceleration gear 50 is rotated using the rotating force transmitted from the second acceleration gear 40 at an increased rpm, compared to that of the second acceleration gear 40.

[59] The first chain 60 connects the chain wheel 110 of the second acceleration gear 40 to the shaft of the third acceleration gear 50 to transmit rotating force from the second acceleration gear 40 to the third acceleration gear 50.

[60] The wheel gear 70 is connected to the third acceleration gear 50 and receives rotating force from the third acceleration gear 50 to rotate the wheel 11.

[61] In detail, the wheel gear 70 has an H-shaped symmetrical structure such that a plurality of chain wheels 110, which have different diameters to form more than one stage power transmission structure, is provided on each of opposite ends of the wheel gear 70. The wheel gear 70 is provided on the shaft of the rear wheel of the bicycle.

[62] The second chain 80 connects the chain wheel 110 of the third acceleration gear 50 to the chain wheel of the wheel gear 70 to transmit rotating force from the third acceleration gear 50 to the wheel gear 70.

[63] Preferably, the second chain 80 comprises a pair of second chains to reliably transmit rotating force from the third acceleration gear 50 to the wheel gear 70. However, as shown in Fig. 6, only one second chain 80 may be provided between the third acceleration gear 50 and the wheel gear 70.

[64] The operation of the bicycle 1 according to the preferred embodiment of the present invention having the above-mentioned construction will be described herein below with reference to Figs. 3 through 9.

[65] When the driver, who sits on the seat 13 provided on the main body frame 10, rotates the pedals 14, the pedal gear 20 is rotated at the same rpm as the pedals 14.

[66] Then, the rotating force of the pedal gear 20 is transmitted to the first acceleration gear 30 with increased rpm. Moreover, the rotating force is transmitted to the wheel gear 70 at an rpm that is further increased via the second acceleration gear 40 and the third acceleration gear 50.

[67] As a result, the wheel gear 70, which is rotated by the rotating force transmitted through the above-mentioned process, rotates the rear wheel 11. As such, the bicycle can be easily accelerated despite being pedaled at a relatively low rpm.

[68] Furthermore, even when the driver rotates the pedals 14 at an increased speed, because the pedal gear 20, the first acceleration gear 30, the second acceleration gear 40, the third acceleration gear 50 and the wheel gear 70 are disposed at the center with respect to the lateral direction of the main body frame, the pedals are rotated in a state in which the bicycle maintains its balance. Therefore, the bicycle is prevented from being tilted when traveling, thus enhancing its traveling stability.