VARIABLE PEDAL DRIVING DEVICE OF BICYCLE

Abstract: A variable pedal driving device of a bicycle which can extend, upon running, a distance between crankshafts which transmit a rotating force of pedals to a rear wheel and the pedals to thereby obtain a maximum driving energy, at the expense of a minimum physical energy consumption. The variable pedal driving device includes: first and second power transmission units (6 and 6') installed on both sides of a main shaft (10) mounted on a shaft pipe (3) of a shaft hole (2) of a bicycle frame (1); first and second slide pipes (8 and 8') assembled on first and second fixed shafts (42 and 42') of first and second rotary levers (4 and 4') rotatably mounted on both ends of the shaft pipe (3); first and second pedals (7 and 7') installed on front ends of the first and second slide pipes (8 and 8'); and first and second crankshafts (5 and 5') mounted on first and second rotary shafts (61 and 61') of the power transmission units (6 and 6') and slidingly assembled on first and second slide holes (81 and 81') of the first and second slide pipes (8 and 8'), the first and second rotary shafts (61 and 61') of the crankshafts (5 and 5') and the main shaft (10) being engaged with each other and the second rotary shaft (61') of the second power transmission unit (6') being engaged with a chain sprocket (9) connected by means of a chain (16) with a rear wheel (15).

Description: VARIABLE PEDAL DRIVING DEVICE OF BICYCLE Technical Field The present invention relates to a bicycle, and more particularly, to a variable pedal driving device of bicycle which can extend, upon running, a distance between crankshafts which transmit a rotating force of pedals to a rear wheel and the pedals to thereby obtain a maximum driving energy, at the expense of a minimum physical energy consumption. Background Art Generally, an existing bicycle has been designed to have a fixed distance between crankshafts and pedals and therefore, its running force depends only upon a driving force of the pedals assembled with the crankshafts. Under such the driving structure of the bicycle, since the rotating force of the pedals is exerted within a predetermined rotary radius, the bicycle should need lots of driving energy upon running upward climbing road. To improve this problem as well as to obtain an effective driving energy, it is well known that a change gear is newly installed to optimize the running force of the bicycle. However, although the change gear has been mounted, the pedals, which are a power source of the running force of the bicycle, maintains a constant rotary radius to thereby provide the same driving energy amount. It can be therefore appreciated that installation of the change gear fails to provide a desired driving force. Due to such the failure, there occurs a need to vary the restrictive rotary radius of pedals to thereby optimize the running force of the bicycle at the expense of a minimum driving energy consumption. Disclosure of Invention An object of the present invention is to provide a variable pedal driving device of a bicycle which can improve a structural feature of crankshafts on which pedals are installed to enlarge a rotary radius of the pedals, upon running, thus to obtain an optimum driving energy at the expense of minimum physical energy consumption, whereby when the bicycle runs upward climbing road or a long distance, it provides a minimum fatigue to a user. To achieve this and other objects according to the present invention, a variable pedal driving device of a bicycle includes: first and second power transmission units installed on both sides of a main shaft mounted on a shaft pipe of a shaft hole of a bicycle frame; first and second slide pipes associated on first and second fixed shafts of first and second rotary levers rotatably mounted on both ends of the shaft pipe; first and second pedals installed on front ends of the first and second slide pipes; and first and second crankshafts mounted on first and second rotary shafts of the power transmission units and slidingly associated on first and second slide holes of the first and second slide pipes, the first and second rotary shafts of the crankshafts and the main shaft being engaged with each other and the second rotary shaft of the second power transmission unit being engaged with a chain sprocket connected by means of a chain with a rear wheel. Brief Description of Drawings FIG. 1 is a side view illustrating a variable pedal driving device constructed according to a first embodiment of the present invention; FIG. 2 is a perspective view illustrating main parts of FIG. 1; FIG. 3 is a sectional view of FIG. 1; FIG. 4 is an exploded perspective view of FIG. 1; FIGS. 5A to 5C are side views illustrating operational states of FIG.l; FIG. 6 is an exploded perspective view illustrating a variable pedal driving device constructed according to a second embodiment of the present invention; FIG. 7 is a sectional view illustrating an assembling state of FIG. 6; FIGS. 8A to 8C are side views illustrating operational states of FIG.6; and FIGS. 9A and 9B are sectional views illustrating main parts of FIG. 6. Best Mode for Carrying Out the Invention FIG. 1 is a side view illustrating a variable pedal driving device constructed according to a first embodiment of the _ present invention, FIG. 2 is a perspective view illustrating main parts of FIG. 1 , and FIG. 3 is a sectional view of FIG 1. Furthermore, FIG. 4 is an exploded perspective view of FIG. 1, and FIGS. 5A to 5C are side views illustrating operational states of FIG.l. The present invention is characterized by that the distance between crankshaft 5 and 5' and pedals 7 and 7' which are each installed opposed at an angle of 180° to each other on a shaft hole 2 of a bicycle body's frame 1 is adapted to be varied and extended during running. Now, an explanation on the construction of a variable pedal driving device constructed according to a first embodiment of the present invention will be in detail discussed hereinafter. A shaft pipe 3 is assembled on the shaft hole 2 of the frame 1 and coupling holes 41 and 41' of rotary levers 4 and 4' are rotatably assembled on both sides of the shaft pipe 3. A main shaft 10 is installed on the inner side of the shaft pipe 3 and power transmission units 6 and 6' and crankshafts 5 and 5' are respectively installed on the both sides of the main shaft 10. The rotary levers 4 and 4' and the crankshafts 5 and 5 ' on both sides of the shaft pipe 3 are installed opposed to each other and the power transmission units 6 and 6' between the rotary levers 4 and 4' and the crankshafts 5 and 5' are under the same structure. On the both ends of the main shaft 10 installed on the inner side of the shaft pipe 3, differential tooth wheels 63 and 63' of the power transmission units 6 and 6' are installed via the coupling holes 41 and 41'. Since each of the power transmission units 6 and 6' takes a separatable shape, cases 65 and 65' of them are designed to be separated from each other by means of assembling bolts 66 and 66'. The differential tooth wheels 63 and 63' installed on the main shaft 10 and driving tooth wheels 62 and 62' are installed on the interior of the power transmission units 6 and 6'. In this case, the differential tooth wheels 63 and 63' and the driving tooth wheels 62 and 62' are each connected to each other by means of chains 67 and 67'. The driving tooth wheels 62 and 62' are installed on rotary shafts 61 and 61' of the cases 65 and 65', and the crankshafts 5 and 5' are fixedly assembled on the one ends of the rotary shafts 61 and 61' by means of fixing nuts 52 and 52'. Slide pipes 8 and 8' on which pedals 7 and 7' are mounted are assembled on fixed shafts 42 and 42' installed on the front sides of the rotary levers 4 and 4', and the crankshafts 5 and 5' are inserted into slide holes 81 and 81' of the slide pipes 8 and 8'. Meanwhile, a coupling pipe 91 is formed on the one side of the shaft pipe 3, and a chain sprocket 9, which is connected by means of a chain 17 with a rear wheel 15, is rotatably installed as a unitary body on the coupling pipe 91. A rotary tooth wheel 12 is fixedly assembled on the chain sprocket 9, which is connected by means of a chain 13 with a driven tooth wheel 11 of the rotary shaft 61' having the differential tooth wheel 63' of the one side case 65'. The power transmission units 6 and 6' may be welded to be assembled on the shaft pipe 3 of the shaft hole 2 of the frame 1, but to be easily separated and/or assembled, form male screw pipes 64 and 64' protrudedly toward the interior of the cases 65 and 65'. Thus, the male screw pipes 64 and 64' are screw-assembled with female screws 31 and 31' of the shaft pipe 3 by passing through the coupling holes 41 and 41' of the rotary levers 4 and 4' and the coupling pipes 91 of the chain sprocket 9. In the power transmission units 6 and 6' the rotary shafts 61 and 61' on which the crankshafts 5 and 5' are installed are disposed on the rear wheel 15, such that when the pedals 7 and 7' assembled on the slide pipes 8 and 8' are driven in a forward direction, the crankshafts 5 and 5' which are inserted into the slide holes 81 and 81' of the slide pipes 8 and 8' are slided. As a result, the distance between the rotary shafts 61 and 61' and the pedals 7 and 7' is extended at its maximum. On the other hand, when the pedals 7 and 7' are driven to the rear wheel 16, the length of the crankshafts 5 and 5' is reduced to its original length. FIG. 6 is an exploded perspective view illustrating a variable pedal driving device constructed according to a second embodiment of the present invention, FIG. 7 is a sectional view illustrating an assembling state of FIG. 6, and FIGS. 8A to 8C are side views illustrating operational states of FIG.6. Power transmission units 60 and 60' and crankshafts 50 and 50' are respectively installed on the both sides of a main shaft 10a which is installed on the inner side of a shaft pipe 3a on a shaft hole 2 of a frame 1. In the power transmission units 60 and 60' circular disks 601 and 601' on the main shaft 10a at the outside of the shaft pipe 3a are eccentrically installed on the rear wheel 15, and guide reentrant holes 603 and 603' are formed on the circular disks 601 and 601', on which guide members 604 and 604' having ball bearings 605 and 605' installed on the interior thereof are slidingly assembled. Slide pipes 80 and 80' having pedals 70 and 70' installed on the front sides thereof are assembled on hinge shafts 606 and 606' of the guide members 604 and 604'. The crankshafts 50 and 50', which are fixedly assembled on the both ends of the. main shaft 10a, are slidingly inserted into the slide holes 801 and 801' of the slide pipes 80 and 80'. Shaft holes 501 and 501' of the crankshafts 50 and 50' are inserted on the both ends of the main shaft 10a, such that the crankshafts 50 and 50' are fixedly assembled on the main shaft 10a by means of fixing nuts 502 and 502 ' . Reentrant portions 602 and 602 ' are formed on the circular disks 601 and 601' and a driving tooth wheel 607 is installed on the main shaft 10a of the reentrant portions 602 and 602 ' and is engaged with a differential tooth wheel 608 on the one side thereof. A driven tooth wheel 609 on a coaxial line of the inside of the circular disk 601' is engaged with the differential tooth wheel 608, and the driven tooth wheel 609 is engaged with rotary tooth wheels 901 and 901' of the chain sprocket 90 assembled on the shaft pipe 3a. The differential tooth wheel 608, which is engaged with the driving tooth wheel 607 of the circular disks 601 and 601' eccentrically installed on the main shaft 10a, is installed on a front wheel 14a, such that when the pedals 70 and 70' are driven in a forward direction, the distance between the crank shafts 50 and 50' which are slidingly assembled on the slide pipes 80 and 80' and the pedals 7 and 7' is extended at its maximum. On the other hand, when the pedals 70 and 70' are driven to the rear wheel 15, the length of the crankshafts 50 and 50' is reduced to its original length. Preferably, a cover C is assembled on the reentrant portions 602 and 602' of the circular disks 601 and 601' to thereby protect the main shaft 10a, the driving tooth wheel 607 and the differential tooth wheel 608. The ball bearings 605 and 605' installed on the interior of the guide members 604 and 604' are embodied in various assembling manners, as shown in FIGS. 9A and 9B. Firstly, as shown in FIG. 9A, a plurality of ball bearings 605 and 605' are installed on the guide members 604 and 604', such that they are slidingly assembled in a circulated manner on the guide reentrant holes 603 and 603'. On the other hand, as shown in FIG. 9B, slide protrusions 605a and 605a' are formed as a unitary body on the guide members 604 and 604', such that they are slidingly assembled on the guide reentrant holes 603 and 603' . In the first and second embodiments of the present invention, reference numerals 92 and 902 each designate bearings which are used to rotatably install the chain sprockets 9 and 90 on the shaft pipes 3 and 3a. Under the above construction, if the pedals 7 and 7' are driven, the distance between the pedals 7 and 7' and the crankshafts 5 and 5' is extended, to thereby achieve an optimal running energy. Now, an explanation of an operation of the variable pedal driving device constructed according to the first embodiment of the present invention will be in detail discussed hereinafter. In operation, if the pedals 7 and 7' are driven, the crankshafts 5 and 5 ' are rotated by the rotating force of the pedals 7 and 7'. At the time, the slide pipes 8 and 8' on which the pedals 7 and 7' are assembled are slid along the crankshafts 5 and 5 ' , such that as the rotary radius between the main shaft 10 on which the crankshafts 5 and 5' are installed and the pedals 7 and 7' is varied, it is extended at its maximum when the pedals 7 and 7 ' are rotated in the forward direction. In other words, the rotary levers 4 and 4' are assembled on the shaft pipe 3 and are rotated within the same rotary radius centering around the main shaft 10. The pedals 7 and 7' of the slide pipes 8 and 8' assembled on the front sides of the rotary levers 4 and 4' are rotated centering around the rotary shafts 61 and 61' on which the crankshafts 5 and 5' are installed, such that the distance between the rotary shafts 61 and 61' and the pedals 7 and 7' is extended at its maximum to thereby obtain an optimal running energy, when the pedals 7 and 7' are rotated in the forward direction. In more detail, if the pedals 7 and 7' are rotated in the forward direction, the slide pipes 8 and 8' on which the pedals 7 and 7' are assembled are guided to the crankshafts 5 and 5' assembled on the slide holes 81 and 81' and are then driven toward the forward direction. At the time, since the rotary shafts 61 and 61' are fixedly installed on the rear wheel 15, the slide pipes 8 and 8' are guided by the rotary levers 4 and 4 ' and are extended at its maximum on a point where the main shaft 10 is passed. The rotary shafts 61 and 61' of the crankshafts 5 and 5', which are rotated by the driving force of the pedals 7 and 7 ' , enable the driving tooth wheels 62 and 62 ' within the cases 65 and 65' to be rotated, thus to rotate the differential tooth wheels 63 and 63' connected by means of the chain 67 and 67' with the driving tooth wheels 62 and 62' . The differential tooth wheels 63 and 63' are assembled on the both ends of the main shaft 10 to transmit the driving force of the pedals 7 and 7' to the rear wheel 15, and the driven tooth wheel 11 mounted on the coaxial line on the differential tooth wheel 63' allows the rotary tooth wheel 12 of the chain sprocket 9 connected by the chain 16 to be rotated, such that the chain sprocket 9 is rotated to thereby drive the rear wheel 15 connected by means of the chain 16 with the chain sprocket 9. The rotary radius between the crankshafts 5 and 5 ' and the pedals 7 and 7 ' is extended during the driving of the pedals 7 and 7' in the forward direction to thereby obtain an optimal running energy. Now, an explanation of an operation of the variable pedal driving device constructed according to the second embodiment of the present invention will be in detail discussed hereinafter. In operation, if the pedals 70 and 70' are driven, the rotary radius centering around the main shaft 10a of the crankshafts 5 and 5' on which the pedals 7 and 7' are slidingly assembled is varied to thereby achieve optimal running energy. In other words, if the pedals 70 and 70' are driven, the slide tubes 80 and 80' into which the pedals 70 and 70' are assembled are coupled on the circular disks 601 and 601' by means of the hinge shafts 66 and 66', such that they are guided to the circular disks 601 and 601' eccentrically installed on the main shaft 10a. As a result, when the pedals 70 and 70' are driven in the forward direction, the rotary radius of them can be extended at its maximu . In more detail, if the pedals 70 and 70' are rotated in the forward direction, the slide pipes 80 and 80' on which the pedals 70 and 70' are assembled enable the guide members 604 and 604' on the hinge shafts 606 and 606' to be rotated along the guide reentrant holes 603 and 603' of the circular disks 601 and 601' eccentrically assembled on the main shaft 10a. When the guide members 604 and 604' are driven in the forward direction centering around the main shaft 10a by the driving force of the pedals 70 and 70', the distance between the pedals 70 and 70' and the main shaft 10a can be extended at its maximum. Therefore, when the pedals 70 and 70' on the guide members 604 and 604' slidingly assembled on the circular disks 601 and 601' are driven from a most upper dead point to a most lower dead point, the distance between the crankshafts 50 and 50' on which the pedals 70 and 70' are slidingly assembled and the main shaft 10a is extended at its maximum to thereby achieve an optimal driving energy. The crankshafts 50 and 50' are rotated by the driving force of the pedals 70 and 70', to thereby rotate the driving tooth wheel 607 on the main shaft 10a. Then, the rotating force of the driving tooth wheel 607 is transmitted to the differential tooth wheel 608 and the driven tooth wheel 609 installed on the coaxis of the differential tooth wheel 608. Finally, the rotating force of the tooth wheels 608 and 609 is transmitted to the rotary tooth wheel 901, such that the chain sprocket 90 is rotated and the rear wheel 15 connected by means of the chain 16 with the rotated chain sprocket 90 is thus driven. Industrial Applicability As apparent from the foregoing, a variable pedal driving device of a bicycle constructed according to the present invention can extend at its maximum the rotary radius between pedals, rotary shafts of cases as a main driving shaft of a rotating force and a main shaft of circular disks to transmit the extended maximum rotary radius to a rear wheel, when the pedals are driven in a forward direction, thus to obtain an optimal driving energy at the expense of a minimum physical energy consumption.

Claims: What Is Claimd Is: 1. A variable pedal driving device of a bicycle, comprising: first and second power transmission units installed on both sides of a main shaft mounted on a shaft pipe of a shaft hole of a bicycle frame; first and second slide pipes assembled on first and second fixed shafts of first and second rotary levers rotatably mounted on both ends of said shaft pipe; first and second pedals installed on front ends of said first and second slide pipes; and first and second crankshafts mounted on first and second rotary shafts of said power transmission units and slidingly assembled on first and second slide holes of said first and second slide pipes, said first and second rotary shafts of said crankshafts and said main shaft being engaged with each other and said second rotary shaft of said second power transmission unit being engaged with a chain sprocket connected by means of a first chain with a rear wheel. 2. The variable pedal driving device as claimed in claim 1, wherein said power transmission units are comprised of first and second cases which are assembled on said shaft pipe, first and second driving tooth wheels which are installed on said main shaft within said cases, and first and second differential tooth wheels on said rotary shafts which are connected by means of second and third chains with said driving tooth wheels, whereby a driven tooth wheel which is connected by means of said first chain with a rotary tooth wheel of said chain sprocket is installed on said second rotary shaft of said second differential tooth wheel, to thereby transmit a rotating force of said crankshafts assembled on said rotary shafts to said chain sprocket, and said rotary shafts are eccentrically installed on said rear wheel, such that when said pedals are driven in a forward direction the distance between said pedals and said rotary shafts is extended at its maximum. 3. A variable pedal driving device of a bicycle, comprising: first and second power transmission units installed on both sides of a main shaft mounted on a shaft pipe of a shaft hole of a bicycle frame; first and second slide pipes assembled on first and second fixed shafts of first and second rotary levers rotatably mounted on both ends of said shaft pipe; first and second pedals installed on front ends of said first and second slide pipes; and first and second crankshafts mounted on first and second rotary shafts of said power transmission units and slidingly assembled on first and second slide holes of said first and second slide pipes, said second power transmission unit being engaged with a chain sprocket connected by means of a first chain with a rear wheel. 4. The variable pedal driving device as claimed in claim 3, wherein said power transmission units are comprised of first and second circular disks which are eccentrically installed on the both sides of said main shaft, first and second guide members which are slidingly assembled on first and second guide reentrant holes of said circular disks and are coupled on first and second hinge shafts of said slide pipes, a driving tooth wheel on said main shaft, a differential tooth wheel which is engaged with said driving tooth wheel, and a driven tooth wheel which is installed on a coaxis of said differential tooth wheel and is engaged with a rotary tooth wheel of said chain sprocket, whereby a rotating force of said crankshafts assembled on said main shaft is transmitted to said chain sprocket, and said circular disks are eccentrically installed on said rear wheel, such that when said pedals are driven in a forward direction the distance between said pedals and said main shaft is extended at its maximum.

Inventors: KANG BYUNG NAM, KIM JONG-SUK, PARK HYE-JONG, KANG, BYUNG, NAM, KIM, JONG-SUK, PARK, HYE-JONG
Applicants: KANG BYUNG NAM, KIM JONG SUK, PARK HYE JONG, KANG, BYUNG, NAM, KIM, JONG-SUK, PARK, HYE-JONG
Application year: 1997
Main classification: B62M3
IPC codes: B62M3, B62M9