JP2003312581A - Bicycle provided with automatic elastic change type crank mechanism corresponding to drag - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bicycle provided with an automatic elastic change type crank mechanism wherein the turning radius of a pedal is small in a cruising operation mode, and the turning radius of the pedal is automatically expanded corresponding to drag, and large angular moment is obtained in an operation mode with a heavy load. <P>SOLUTION: A crankshaft 10 is inserted in a hollow shaft 30, and a double shaft structure is rotatably supported to a frame 40 of a bicycle 1. An elastic change type crank A is fixed to the crankshaft 10, and a sprocket gear 31 is fixed to the hollow shaft 30. A spring member 11 is provided between the crankshaft 10 and the sprocket gear 31 directly or indirectly and energized in a direction in which the linear dimension of the crank A, i.e., the turning radius of a pedal 12 is reduced. The length of the crank A is elongated when the pedal 12 is stepped on with a force overcoming a load and contracted when a stepping force disappears. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-wheeled or three-wheeled human-powered bicycle in which wheels are rotated in a forward direction by depressing a pedal, and a pedal arm of a crank corresponding to a large load applied to the bicycle. Relates to a bicycle that automatically expands and contracts and can travel lightly.

[0002]

2. Description of the Related Art When riding a bicycle, starting, accelerating,
Strong drag is generated when climbing slopes and strong pedaling force is required.
The stronger the vehicle is, the faster the vehicle accelerates, and the steeper the vehicle is, the stronger the drag is. Then, after starting, accelerating, and climbing the hill, the drag becomes weaker as the cruise moves to a constant speed. Road resistance, wind direction, and wind force also affect drag.

As a bicycle transmission that has hitherto been widely marketed, there is one in which the ratio of the rotational speed of the pedal to the rotational speed of the rear wheels is manually changed. In the external transmission, the gear shifting is not completed unless the pedal is pedaled after the manual operation and the rear wheels are not rotated a half turn. Therefore, if the driver wants to start from the low gear with the green light, the shift operation from the high gear must be completed before the vehicle stops with the red light. Even with an internal transmission that can change gears while it is stopped, manual operation every time a signal waits is cumbersome and rarely used.

However, actually, for a housewife with a lot of shopping baskets and children in the back, starting is a difficult task, and since he / she does not want to stop temporarily, it causes red light to be ignored. Further, for a housewife or a handicapped person who is forced to drive under such a high load, it is more difficult and dangerous to release the right hand from the steering wheel and perform a gear shift operation with one hand while driving on a slope. Women, elderly people, and people with physical disabilities who can not exert strong power need a transmission, but lack of mechanics, complicated and difficult manual operation hinder the spread, and they are not benefiting from it. Is the current situation.

As shown in FIG. 1, in a normal bicycle 1, the crank 2 has a length of about 16.5 cm, and the front and rear gear ratios are set on the assumption of the crank length and the diameter of the rear wheel 4. There is. Bicycle 1 while rowing pedal 3 one revolution
The distance traveled by is determined by the gear ratio and the rear wheel diameter, but in actual pedaling, the crank length is also relevant. Since the crank structure shown in FIG. 3 has a crank length twice as long as the crank structure shown in FIG. 2, the circumferential length of the rotation locus for one rotation of the pedal 3 is also doubled. If the drag force applied to the sprocket gear 5 is the same in the crank configuration of FIG. 2 and the crank configuration of FIG. 3, the pedal 3 can be rowed with half the force in the crank configuration of FIG. It takes twice as long, because it takes twice as much distance.

The pedal 3 having the crank structure shown in FIG. 2 requires a double force, but since it is a half distance, it can make one rotation in a half time. That is, the linear velocity with respect to the circumference of the pedal 3 is the same, and the angular velocity is doubled. Therefore, when traveling a bicycle, the crank structure of FIG. 3 that allows light rowing is advantageous when climbing a hill having a strong drag force, and the crank structure of FIG. 2 that allows rapid rotation when cruising with a weak drag force is advantageous. The low gear mode of the gear transmission corresponds to the crank configuration of FIG. 3, and the high gear mode corresponds to the crank configuration of FIG. That is, the expansion and contraction of the crank length has the same effect as the transmission.

In the bicycle described in Japanese Patent Laid-Open No. 9-2365, two pedal arms for driving the sprocket are used.
It is a split rocking and bending type, and has a coupled arm structure in which a rocking angle control mechanism and a pedaling force proportional rocking and bending mechanism that applies the elastic force of a metal spring are combined in the rotary connection joint part of both arms. In this pedal arm device, the actual pedal arm length around the center axis of the sprocket is bent and shortened while the effective drive pedal force is generated at the rearward substantially half-rotation pedal phase portion that normally generates the ineffective drive pedal force in the pedal work. At the front approximately half-rotation pedal phase part, the actual pedal arm length is flexed and extended, and in this way the eccentricity of the pedal rotation center axis locus around the sprocket center axis is reduced rearward and at the same time an effective drive torque is secured. Since the pedals are operated as described above, it is said that a labor-saving and light pedal operation feeling can be obtained.

The pedal arm device disclosed in Japanese Unexamined Patent Publication No. 9-2365 will be described with reference to FIGS. 4 to 9. Since the left and right pedals 3 are bent and extended in advance of the sprocket gear 5, the split arms are extended and retracted. The left and right pedals 3, 3 pivotally attached to the arm member 2b can expand and contract the distance from the sprocket center axis 6 (the turning radius of the pedal), but there is no interlocking relationship between the left and right pedals. When cruising with a weak drag, the left and right pedals 3, 3 are
Rotate with a phase interval of 180 degrees. However, when the drag is increased, such as when climbing a slope, as shown in FIG. 7, only the right pedal precedes and extends. Because the pedaling by the passenger is to apply the force mainly from the top to the bottom, and at least it cannot be applied from the bottom to the top.
The left pedal remains shortened.

When the right pedal reaches the bottom dead center as it is, the left pedal does not reach the top dead center as shown in FIG. Here, the left foot is required to perform the operation as shown by the arrow in FIG. 9, but this is extremely unnatural and difficult. At least on steep slopes where inertia is not expected, it is impossible. Even if it is possible to give it away, the movement of the left foot during this period is only a movement to extend the pedal arm, and does not rotate the sprocket gear 5. A bicycle that cannot be given driving torque will stop and fall.

In the first place, it is most difficult to exert force in pedaling when the left and right feet are at the top-bottom dead center. On the slope, the right pedal extended to low gear mode and reached bottom dead center, at that time, the left pedal to be replaced did not reach top dead center,
Moreover, the defect that the high crank mode of the short crank remains in heavy mode occurs every half turn of the pedal. The reason is that the two-part split pedal arm unnecessarily shortens and returns after passing through the bottom dead center, and as a result, a new crank extension operation is required every half rotation. This is the loss of climbing power itself, and cannot be a pedal effort reducing device including self-contradiction.

As described above, the pedal arm device disclosed in Japanese Unexamined Patent Publication No. 9-2365 treats shortening return after bottom dead center as effective, and aims at shortening the trajectory of the rear half of the pedal that does not generate pedal effort. We expect labor saving and light pedal operation by shortening the track, but the contradiction and error will be revealed due to the above reasons when climbing, accelerating, and starting. In addition, distorting the circular orbit of rotation impairs smoothness and hinders the sense of unity between the left and right, and rather makes it difficult to row.

[0012]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention The present invention has been made as a result of earnest research in view of the above-mentioned prior art, and an object of the present invention is to provide a right and left The pedal operates point-symmetrically, the left crank extends with the treading force of the right foot, and when the left foot is changed, the treading force maintains the right length, so it is possible to finish climbing the slope with the left and right lengths always equal during climbing, It is an object of the present invention to provide a bicycle equipped with a drag-compatible automatic expansion / contraction variable type crank.

The automatic expansion / contraction variable type crank mechanism corresponding to the drag, which is the object of the present invention, shifts the bicycle without touching like most automobiles have automatic transmissions. It is not stepped like the machine, but does this steplessly and smoothly without shock. Moreover, since it is neither heavy nor expensive like an electrically assisted bicycle and is not accompanied by charging, it is highly practical.

Further, the drag-adaptive automatic expansion / contraction variable type crank mechanism aimed at by the present invention has a purely mechanical structure, so that the stronger the drag becomes, the more automatically it responds to various situations during running. The crank extends longer and reduces the pedal effort. When the drag becomes weaker, the crank automatically shortens to facilitate high-speed cruising. It is easy to understand how to reduce the pedal effort when driving on a slope, but it is also important how to drive when traveling at high speed. Just as low-gear keeps the fuel economy of the car worse, even if you ride a bicycle, you will only progress slowly and you will get tired if you go the same distance. Another, the top and bottom wheels of the bicycle act as a gyro so that the top is stable at high speeds and sway at low speeds, and a certain high speed is essential to stabilize the bicycle.

Further, in the drag-adaptive automatic expansion / contraction variable type crank mechanism which is the object of the present invention, when a weighted load is applied to one of the left and right pedals, the extended pedal arm does not excessively shorten and pedal operation is comfortable. Moreover, the labor is not wasted.

[0016]

The bicycle of the invention of claim 1 is a two-wheeled or three-wheeled human-powered bicycle (hereinafter, simply referred to as a bicycle) whose wheels rotate in a forward direction by depressing a pedal 12. It is equipped with an automatic expansion / contraction variable type crank mechanism that responds to drag. In this drag-adaptive automatic expansion / contraction variable crank mechanism, a driving sprocket gear 31 is fixed to one end of a hollow shaft 30 that is slidably fitted to the outside of the crank shaft 10, and the hollow shaft 30 is a frame 40 of a bicycle. A crank A of expansion and contraction type in which the position of the pedal 12 with respect to the rotation center of the crank shaft 10 is provided at both ends of the crank shaft 10 with 180 degrees different phase. The crankshaft 10 is reciprocally rotatable within the set angle range with respect to the hollow shaft 30, and when the rotation direction of the crank A when the bicycle moves forward on the road surface is the driving rotation direction. The crankshaft 10 is opposed to the drive rotation direction by a spring member 11 provided directly or indirectly between the hollow shaft 30 and the crankshaft 10. Are rotated biased, the bicycle cruising operation load mode, the rotational phase and the hollow shaft 30 of the crankshaft 10
While the rotational phase of the crankshaft 10 and the rotational phase of the hollow shaft 30 coincide with each other, the spring member 11 is deformed to cause a difference between the rotational phase of the crankshaft 10 and the rotational phase of the hollow shaft 30 in a weighted load operation mode such as climbing. The spring member 11 is set, and the pedal with respect to the center of rotation of the crankshaft 10 corresponding to the rotational phase difference between the crankshaft 10 and the hollow shaft 30 generated by the stepping force against the weighted load received by the bicycle. The crank extension / contraction mechanism B for changing the rotational radius position of 12 is provided.

In the bicycle of the invention of claim 2, in addition to the structure of the invention of claim 1, a plate-like stay 32 parallel to the surface of the sprocket gear 31 is fixed to the other end of the hollow shaft 30, Sprocket gear 31 and board stay 32
The crank A is reciprocally rotatable within a set angle range with respect to (hereinafter collectively referred to as sprocket gear 31 etc.), and the pedal 12 at the tip of the crank A is reciprocally rotatable.
By the stepping force against the weighted load on the crank A, the phase of the crank A leads the phase of the sprocket gear 31 and the like while resisting the restoring force of the spring member 11,
The crank A and the sprocket gear 31 are arranged so that the crank length expands and contracts due to the leading of the crank A.
Are connected by a crank extension / contraction mechanism B, and the crank extension / contraction mechanism B is formed of one of a link mechanism, a gear mechanism, or a combination mechanism thereof.

In the bicycle of the third aspect of the invention, in addition to the structure of the first or second aspect of the invention, the expansion / contraction variable type crank has arm slides fixed to both ends of the crankshaft 10 in the radial direction. The dynamic guide case 13 and a pedal arm 14 that slides in the dynamic guide case 13 are formed. The crank extension mechanism B is formed by a link mechanism having a guide link 15, and one end of the guide link 15 is formed. A pivot 15a parallel to the crankshaft 10 is pivotally attached to the tip of the pedal arm 14, and the other end of the guide link 15 is parallel to the crankshaft 15b.
Thus, in the vicinity of the leading end of the movable range of the crank A, the crank A is pivotally attached to the side surface of the sprocket gear 31 and the like.

In the bicycle according to a fourth aspect of the invention, in addition to the structure of the first or second aspect of the invention, the expansion-contraction variable type crank has arm slides fixed to both ends of the crankshaft 10 in the radial direction. The crank extension mechanism B includes a rack 16 formed on a side surface of the pedal arm 14 and the arm slide guide case. 13, a first pinion 17 supported at a position away from the crankshaft 10, a second pinion 19 supported by an arm slide guide case 13 so as to rotate integrally with the first pinion 17, and a precursor sprocket The gear mechanism is composed of an arc gear 33 concentrically provided on the side surface of the gear 31 and the like, and engages the rack 16 and the first pinion 17 with each other. , It is engaged with the circular arc gear 33 and the second pinion 19.

In the bicycle of the fifth aspect of the present invention, in addition to the configuration of the first or second aspect of the invention, the distal end side pedal arm 14b and the base of which the expansion / contraction variable type crank A is connected by a joint shaft 20 are connected. It is composed of a bendable pedal arm 14a composed of a side pedal arm 14c, a fan gear 21 is provided at the base of the tip side pedal arm 14b, and an arc gear 33 is concentrically fixed to the side surface of the sprocket gear 31 and the like. By engaging the fan-shaped gear 21 with the arc gear 33, the crank extension mechanism B is configured by a combination of a link mechanism and a gear mechanism.

According to the bicycle of the invention of claim 6,
In addition to the configuration of the invention of claim 2 or claim 5, the crank A is configured by a pantograph mechanism C that is a kind of link mechanism, and the link 2 of the pantograph mechanism C is provided.
3a is fixed to the crankshaft 10, and another link 23b of the pantograph mechanism C parallel to the link 23a is pivotally attached to the root side pedal arm 14c at a base end side by a pivot 26 parallel to the crankshaft 10. As a result, the crank extension / contraction mechanism B is used, and the tip end side portion of the link 23b is used as the tip end side pedal arm 14b.

According to the bicycle of the invention of claim 7,
In addition to the configuration of the invention of claim 2 or claim 5, the crank A comprises a tip side pedal arm 14b, a root side pedal arm 14c and a connector 14d, and a root part of the tip side pedal arm 14b is the root. It is pivotally attached to the side pedal arm 14c by a pivot 27 parallel to the crankshaft 10, the root pedal arm 14c is fixed to the hollow shaft 30, and the connector 14d is the crankshaft 1
The fan-shaped gear 21a at the base end of the distal pedal arm 14b and the fan-shaped gear 21b at the base end of the connector 14d mesh with each other, and the crank expansion / contraction mechanism B is a combination of a gear mechanism and a link mechanism. Consists of.

In the bicycle according to the invention of claim 8, in addition to the structure of the invention of claims 1 to 8, the spring member 11 is one of a torsion spring and a tension coil spring, and the spring member 11 A spring force adjusting mechanism is added to one end of the.

In the bicycle of the ninth aspect of the invention, in addition to the above configuration of the first to eighth aspects of the invention, the crank extension / contraction mechanism B includes a damper 45 that acts as a buffer when the crank A is shortened.

According to the bicycle of the invention of claim 10, claim 9
In addition to the above configuration of the invention, the damper 4 is provided by a part of the arm sliding guide case 13 and the pedal arm 14.
5 is formed.

According to the bicycle of the invention of claim 10, claim 9
In addition to the above configuration of the invention, the spring member 11 is a tension coil spring, one end of which is engaged with the sprocket gear 31 and the like, the other end of which is engaged with a part of the crank A, and the crankshaft 10 It is located farther away,
The coil spring 11a is equipped with a damper 45 which operates only when the tension coil spring is shortened.

[0027]

According to the invention of claim 1, when the bicycle travels at a normal cruising speed, the length of the crank A is shortened, while a load higher than the cruising speed is applied.
The restoring force of the spring member 11 is adjusted and set so that the pedal 12 precedes the sprocket gear 31 when strongly depressed against this. Ride a bicycle like this,
When the pedal 12 is pedaled, the crank A remains shortened unless the headwind is particularly strong on a flat ground, and the force of stepping on the pedal 12 does not reach the force to extend the contracted spring member 11, and the crankshaft 10 The hollow shaft 30 and the hollow shaft 30 rotate together with respect to the vehicle body frame 40, and the force depressing the pedal 12 is transmitted to the sprocket gear 31, so that the bicycle runs in the normal cruise mode.

Next, when a heavy load is applied to the bicycle, such as a climbing slope, a strong headwind, and a rapid speed increase, the pedal 12 is strongly resisted by the pedaling force, and a strong stepping force to overcome this is exerted. When applied to the pedal 12, the spring member 11 is extended and the pedal 12
Rotates ahead of the sprocket gear 31, the length of the crank A is extended by the action of the crank expansion / contraction mechanism B, and the rotational moment increases even with the same stepping force on the pedal 12, resulting in lighter weight and stronger resistance. Beat the car and drive the bicycle forward. In other words, it becomes a weighted load mode operation. When the crank A rotates ahead of the sprocket gear 31, the cranks A on both the left and right sides perform exactly the same angular change and extension action with respect to the sprocket gear 31, and a load is applied to either the left or right pedal 12. As long as the crank A is applied, the crank A is still extended, and the crank A on the pulling side is not shortened.

According to the second aspect of the invention, since the crank expansion / contraction mechanism is composed of a link mechanism, a gear mechanism or a combination thereof, the pedaling force of the pedal 12 is mechanically and reliably transmitted to the sprocket gear 31. . When the stepping force is larger than the restoring force of the spring member 11, the crank A reaches the limit position most preceding the sprocket gear 31, and reaches the position corresponding to the drag force.
After that, they rotate together in the driving direction.

In addition to the above-mentioned effects, the pedal arm 14 slides in the axial direction relative to the arm slide guide case 13, and the guide link 15 is provided. The crank extension mechanism B is a link mechanism including a sliding fitting mechanism.
When the arm sliding guide case 13 and the pedal arm 14 precede the sprocket gear 31, the guide link 15 gradually moves away from the arm sliding guide case 13, and the pedal arm 14 is pulled out from the arm sliding guide case 13, so that the crank A The length is increased, the rotational moment is increased, and a larger rotational force can be obtained even with the same stepping force, overcoming the weighted load applied to the bicycle,
It works to move the bicycle forward.

In the invention of claim 4, a rack 16 is formed on the side surface of the pedal arm 14 of the invention of claim 3, and the rack 16 and the first pinion 17 are engaged with each other, the second pinion 19 and the circular arc. Since the gear mechanism for expanding and contracting the pedal arm 14 by interlocking with the gear 33 is used as the link expanding / contracting mechanism B, the structure is simplified.

According to the fifth aspect of the present invention, the crank A has a bendable pedal arm 14a having a joint shaft 20.
The crank expansion / contraction mechanism B includes the fan-shaped gear 21 at the base of the tip side arm member 14b and the sprocket gear 3
Since the gear mechanism is composed of the circular arc gear 33 provided integrally with the first gear, the same operation as the invention according to the first to fourth aspects is achieved.

In the sixth aspect of the invention, the crank extension mechanism B is entirely formed by a link mechanism,
Since no complicated and costly gears are used for processing, the operation is the same as that of each of the first to fourth and sixth aspects of the invention, but the cost is reduced.

According to the eighth aspect of the invention, since the restoring force of the spring member 11 can be adjusted, the spring force can be easily adjusted according to the leg force and the physical strength of the occupant.

According to the ninth aspect of the present invention, since the damper 45 is incorporated in the crank expansion / contraction mechanism B, even if the stepping foot is disengaged from the pedal 12 in the operation mode of a weighted load such as when climbing a slope, the crank There is no risk that A will be rapidly shortened and returned by the spring member 11. The position of the pedal 12 whose radius of gyration has once increased due to an increase in the weighted load does not decrease rapidly even if the load applied to the pedal 12 fluctuates rapidly, let alone the crankshaft 1 once.
Little fluctuation during 0 rotation.

According to the tenth aspect of the invention, since the damper 45 is formed by the arm sliding guide case 13 and a part of the pedal arm 14, the number of parts is small and the structure is simplified.

According to the eleventh aspect of the invention, since the spring member 11 is a coil spring and the damper 25 is housed inside the coil spring member 11a, there is an action that does not take up an extra space.

[0038]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1 shown in FIGS. 10 and 11 is an example of each invention described in claims 1, 2 and 3. On the left and right ends of the crankshaft 10,
One arm sliding guide case 13 for each
The phases are fixed by 80 °. A pedal arm 14 is fitted in the arm sliding guide case 13 so as to be slidable in the length direction thereof.
A pedal 12 is attached to the tip of 4 by a pivot 15a parallel to the crankshaft 10.

At one end of the hollow shaft 30, a spcket gear 31 around which the endless chain 7 is wound is formed, and at the other end of the hollow shaft 30, a disc stay 32 having a side surface parallel to the sprocket gear 31 is formed. There is. In the figure, the hollow shaft 30, the sprocket gear 31, and the board-like stay 32 are shown integrally, but the point is that they need only be fixed so as not to cause phase shifts with each other, and these fixing means are not limited.

On the side surface of the sprocket gear 31 facing the arm sliding guide case 13, a first stopper 35 and a second stopper 36 are arranged on an arbitrary concentric circle from 30 degrees to 60 degrees with respect to the central axis of the sprocket gear 31. It is planted so that it forms an angle. Both side surfaces of the arm slide guide case 13 hit the first stopper 35 or the second stopper 36, so that the swing range with respect to the sprocket gear 31 is limited.

Between the arm sliding guide case 13 and the sprocket gear 31, a spring member 11 made of a tension coil spring is attached. The crank A including the arm sliding guide case 13 and the pedal hood 14 is rotationally biased by the spring member 11 in a direction (counterclockwise direction in FIG. 1) opposite to the driving rotational direction for moving the bicycle 1 forward. There is. The arm slide guide case 13 thus biased contacts the first stopper 35 at the rearmost end with respect to the pedal driving direction.

One end of the guide link 15 is pivotally attached to the tip end of the pedal arm 14 protruding from the arm sliding guide case 13 by the pivot shaft 15a. In the illustrated example, the pivot shaft 15a is also used as the rotation center shaft of the pedal 12, but other pivot shafts are also included in the embodiment of the present invention. The other end of the guide link 15 is pivotally attached by a pivot shaft 15b parallel to the crankshaft 10 near the peripheral edge of the sprocket gear 13 that is ahead of the arm sliding guide case 13 with respect to the driving direction.

At the opposite end of the hollow shaft 30, a disc-shaped stay 32 is provided instead of the sprocket gear 13, and the disc-shaped stay 32 has a rotationally symmetrical position with respect to the guide link 15 of the sprocket gear 31. Another guide link 15 of the same size is attached to. The spring member 11 may be provided on the board stay 32 side, but it is not always necessary.

In the first embodiment, when the bicycle is in a normal cruising operation or on a downhill, the pedal 12 is hardly loaded, or even if there is a little load, the spring member 11 contracts. The turning radius of the pedal arm 14 is shorter than that of a normal bicycle.

Next, when the bicycle comes to a slope or receives a strong headwind, the bicycle and the occupant are subjected to a heavier load, and the pedal 12 is strongly depressed in order to overcome the load and advance the bicycle. At this time, the spring member 11 expands in response to the load due to the uphill slope or the headwind on the bicycle itself, and the phase of the pedal 12 precedes the sprocket gear 31, and the pedal arm 14 is moved by the guide link 15. It is pulled out from the arm sliding guide case 13 to the maximum normal crank length of the bicycle. As a result, the turning radius of the pedal 12 is increased and a large turning moment is obtained, so that the weighted load applied to the bicycle can be sufficiently overcome and the pedal 12 can be moved forward.

Further, in the first embodiment, the crank extension / contraction mechanism B is a link mechanism having a small number of pure mechanical parts for pivotally connecting the pedal arm 14 sliding in the lengthwise direction, the guide link 15 and the guide link 15. Does not push up costs. The radius of rotation of the pedal 12 automatically corresponds to the load applied to the bicycle, and if the load is heavy, the arm slide guide case 13 moves to the most advanced position where it abuts on the second stopper 36, and thereafter. It will rotate together with the sprocket gear 31.

The arm sliding guide case 13, the pedal arm 14 and the guide link 15 are the same as those of the bicycle frame 4.
Also on the side opposite to 0, the crankshaft 10 and the hollow shaft 30 are provided in a rotationally symmetrical position with a phase difference of 180 ° with respect to the plate-like stay 32, just like the sprocket gear 31 side. Therefore, if the turning radius of either the left or right pedal 12 is changed, the turning radius of the pedal on the other side is also changed, and as long as there is a load on either pedal 12, the turning radius of the pedal 12 is insignificant. It is not changed by itself. In addition, since the air damper is composed of the arm sliding case 13 and a part of the pedal arm 14 as described above, the number of parts does not increase, the appearance does not become complicated, and the discomfort is small.

Embodiment 2 shown in FIG. 12 and FIG. 13 is an embodiment of the invention described in claim 4, and the parts already explained in the means to be solved by the invention and the operation of the invention are incorporated by reference. , Repeated description is omitted. A rack 16 is integrally formed on a side surface of the pedal arm 14, and a second pinion 19 that rotates integrally with a first pinion 17 that meshes with the rack 16 is integrally formed by die casting or the like. The first pinion 17 and the second pinion 19 may be molded separately and fixed to a common pinion shaft 18 attached to the arm sliding guide case 13 with a key or the like.

The second pinion 19 is for the sprocket gear 3
1 is meshed with an arc gear 33 attached to the side surface of the No. 1 and the center of curvature of the arc gear 33 is the sprocket gear 3
It is a divergent or fan-shaped gear at the center of 1. In the disc-shaped stay 32 arranged on the opposite side of the sprocket gear 31 with respect to the bicycle frame 40, a part of the outer peripheral surface is formed as an arc gear 33a having the same diameter as the arc gear 33. In addition, the same reference numerals as those in the first embodiment are the same components or components.

In the second embodiment, as described above, the bicycle is subjected to a load resistance, and when the pedal 12 is strongly depressed to overcome the resistance, the spring member 11 extends, and the pedal arm 14 moves the arm sliding guide case 13. Together with the sprocket gear 31, the sprocket gear 31
Second pinion 19 meshing with the circular arc gears 33, 33a on the side
The first pinion 17 integrated with the second pinion 19 is also shown in FIG.
The pedal arm 14 having the rack 16 that rotates in the clockwise direction and meshes with the first pinion 17 is pulled out from the arm slide guide case 13, and the turning radius of the pedal 12 increases. When the pedaling force applied to the pedal 12 becomes weaker, the spring member 11 contracts and the pedal 12 returns to the original position. Other operations are almost the same as those in the first embodiment.

The third embodiment shown in FIG. 14 is an example of the invention described in claim 5. Where the means for solving the problems and the operation of the invention have been already described, the description will be incorporated and repeated description will be omitted. When the pedaling force of the pedal 12 becomes stronger, the spring member 11 expands, and the base pedal arm 14c rotates ahead of the sprocket gear 31. As a result, as the phase of the tip pedal arm 14b changes, The engagement position between the integral fan gear 21 and the arc gears 33, 33a on the sprocket gear 31 side is changed, and the tip side pedal arm 14b is rotated clockwise in FIG. 14 to finally respond to the stepping force. Comes to the position shown by the chain double-dashed line in FIG. On the opposite side of the bicycle frame 40, the outer peripheral portion of the board-like stay 32 is an arc gear 33a as in the second embodiment. When the pedaling force on the left and right pedals 12 disappears, the spring member 11 contracts and each pedal 12 returns to its original position.

Embodiment 4 shown in FIG. 15 is an embodiment of the invention described in claim 6. The crank extension mechanism B is composed of a pantograph mechanism C which is a kind of link mechanism. The pantograph mechanism C has two pairs of opposing links 2.
2a and 22b and links 23a and 23b are arranged so as to form a parallelogram, and are pivotally attached by four pivots 25 that are parallel to the crankshaft 10.
The intermediate portion of 3a is fixed to the crankshaft 10, and the link 23b on the other side is extended outward to extend the pedal arm 14
Is formed, and the pedal 12 is pivotally attached to the tip thereof.

One end of a spring member 11 made of a tension coil spring is attached to the tip of the extension of the link 23a.
The other end of the spring member 11 is attached to the outer peripheral edge of the sprocket gear 31. The spring member 11 pulls the pantograph mechanism C in the folding direction and urges it in a direction to reduce the radius of rotation of the pedal 12. When the pantograph mechanism C is folded to the initial state, the link 2
The side surface of the extension portion 3a is in contact with the first stopper 35.

When operating in the weighted load mode, the pedal 1
When 2 is strongly depressed, the spring member 11 extends and the link 2
3a rotates about the crankshaft 10 in the clockwise direction in FIG. In association with the rotation of the link 23a, the pantograph mechanism C is deformed from the solid line position to the two-dot chain line position, and the link 23b rotates about the pivot 26 in the clockwise direction in FIG. In this way the pantograph mechanism C
Is expanded and deformed as a crank extension mechanism B, so that the turning radius of the pedal 12 is expanded. Even if the crankshaft 10 and the root portion of the link 23b are connected by the root side pedal arm 14c parallel to the pair of links 22a and 22b, it is included in the fourth embodiment. That is, the link 22a can be omitted. The link 23a is connected to the base pedal arm 12
When used in combination with c and the link 22b, the strength is increased.
Since the stress is distributed to the three parties, the plate thickness of each of the links 23a and 23b and the root side pedal arm 12c can be reduced. In the fourth embodiment, the crank expansion / contraction mechanism B is the pantograph mechanism C, and the joint portions are all rotationally fitted, and there is no sliding fitting or gear transmission mechanism.
There is little movement resistance, there is no danger of failure, and operation is smooth.

The fifth embodiment shown in FIG. 16 is an embodiment of the invention described in claim 7, and is a kind of modification of the fourth embodiment. The difference from the fourth embodiment is that a fan gear 21 is used instead of the pantograph mechanism C,
The spring member 11 made of a tension coil spring is hooked between the outer peripheral edge of the sprocket gear 31 and the tip of the fan gear 21b. The spring member 11 biases the pedal arm 14 in a direction to pull it inward. When the pedal 12 is strongly depressed in response to the weighted load, the pedal arm 14a rotates in the clockwise direction in FIG. 16 about the pivot 27 and moves to the position indicated by the chain double-dashed line.
The radius of gyration of the crankshaft 10 around the crankshaft 10 extends. Along with the rotation of the pedal arm 14a, the arc gear 33 meshing with the fan-shaped gear 21 at the base of the pedal arm 14a rotates about the crankshaft 10 in the counterclockwise direction in FIG.

The sixth embodiment shown in FIG. 17 is an embodiment of the invention described in claims 9 and 10 and is a crank A.
Is partially or entirely configured as an air damper 45. The structure of the air damper 45 is as follows, for example. That is, the arm sliding guide case 1
3, the base end wall portion of 3 is closed to serve as an outer cylinder member of the damper, the base end portion of the pedal arm 14 serves as a plunger member of the damper, and the pedal arm 14 is provided on the base end wall portion of the arm slide guide case 13. Is retracted into the arm sliding guide case 13 and the crank length is shortened, the small hole 50 for allowing air to flow out from the inside of the arm sliding guide case 3 and the pedal arm 14 are provided in the arm sliding guide case 1.
A large hole 51 for allowing air to flow into the inside of the arm sliding guide case 3 when the crank length is extended by protruding from 3
Are formed. The opening area of the large hole 51 is set sufficiently larger than the opening area of the small hole 50.
A check valve 52 that opens the large hole 51 when the pedal arm 14 protrudes and closes the large hole 51 when the pedal arm 14 retracts is provided on the inner surface side of the. In addition,
The check valve 52 is urged to rotate by a closing direction by a weak torsion spring, so that the large hole 5
It is also possible to prevent the check valve 52 from opening unnecessarily due to the effect of its own weight when the 0 comes to the upper position. With this air damper 45, when the pedal arm 14 extends, the pedal arm 14 does not receive a large resistance, which results in swift operation. On the contrary, when the pedal arm 14 retreats, a large resistance is received, which is slow. It will work. As a result, an appropriate cushioning action can be obtained when the turning radius of the pedal 12 is shortened. Other configurations are as described in the section of means to be solved by the invention, and are incorporated herein by reference.

The seventh embodiment shown in FIG. 18 is an embodiment of the invention described in claim 8. One end of the spring member 11a composed of a coil spring is connected to a part of a crank expansion / contraction mechanism B such as a sprocket gear 31 or a pedal arm 14 via a spring force adjusting mechanism D. One end of the spring member 11a is connected to a screw rod 48, and a female screw pedestal 49 screwed with the screw rod 48 is attached to the sprocket gear 31 side. When the screw rod 48 is rotated by an appropriate means to move the screw rod 48 forward and backward with respect to the female screw pedestal 49, the initial setting of the restoring force of the spring member 11a can be changed easily and accurately.

The eighth embodiment shown in FIG. 19 is an embodiment of the invention described in claim 11. When the damper 45 is used together with the spring member 11 in each of the embodiments, the spring member 11 is a tension coil spring 11a. The damper 45 is configured and the damper 45 is housed in the internal space. This saves assembly space. The base end mounting portion 45a of the cylinder body of the damper 45 is mounted on the sprocket gear 31 side together with one end of the spring member 11a, and the tip mounting portion 4 of the plunger 45b of the damper 45 is mounted.
5c is attached to a proper position of the crank expansion / contraction mechanism B together with the other end of the spring member 11a. A known air damper or hydraulic damper can be used as the damper 45 in the sixth and seventh embodiments. The damper 45 may not be housed inside the spring member 11, but may be independently installed outside.

When the dampers are installed inside and outside the spring member in this way, even if the treadle comes off the pedal 12 while climbing a slope, the damper member acts as a buffer, so that the crank member A is shortened rapidly by the spring member 11. There is no danger of returning. The cushioning damper at the time of contraction operation of the crank A has the function of stabilizing the rotation of the pedal in addition to the above-mentioned danger prevention depending on the setting of the damper rate. When both feet reach near the top-bottom dead center and the pedaling force weakens when climbing the slope, the crank A tries to shorten, but the damper delays the shortening for a moment and the top-dead center is overrun. Further, it suppresses the excessive expansion and contraction even in the entire rotation range, and suppresses the feeling of idling due to the rotation difference of the double shaft structure.

As the spring member 11, the coil spring 1 is used.
Not limited to 1a, a torsion spring or the like can be used. In this case, the torsion spring serves as a replacement member for the coil spring 11a described above and the sprocket gear 31 and the arm sliding guide case 1 of the crank expansion / contraction mechanism B.
It can be mounted between the crankshaft 10 and the hollow shaft 30 as in the ninth embodiment shown in FIGS. 20 to 22, though it can be mounted between the crankshaft 10 and the hollow shaft 30. In the ninth embodiment, the main body coil portion of the torsion spring 11b is fitted over both the end portion of the hollow shaft 30 and the crankshaft 10, and one straight end portion 11d of the torsion spring 11b is provided on the hollow shaft 30 as a stopper projection 37.
The other straight end 1 of the torsion spring 11b.
1e is hooked on a stopper protrusion 38 provided on the crankshaft 10.

In this ninth embodiment, as shown in FIGS. 20 and 21, the hollow shaft 30 is provided with an arcuate groove 51 opened at a predetermined angle in the circumferential direction, and is planted in the crankshaft 10 in the radial direction. The restricted pin 52 is inserted into the arcuate groove 51. The regulation pin 52 reciprocally rotates in the arc-shaped groove 51 with the rotation of the crankshaft 10, and both ends 51a of the arc-shaped groove 51,
51b is the first stopper 35 and the second stopper 36.
Plays the role of. The hollow shaft 30 is provided with a sprocket gear 31 and a board-like stay 32 as in the above embodiment. A crank A is connected to the crankshaft 10, and a crank extension mechanism B is similarly provided between the crank A and the sprocket gear 31.

The crankshaft 10 is returned to the counterclockwise direction with respect to the hollow shaft 30 in FIG. 20 by the torsion spring 11b. In the normal cruise mode, when the restoring force of the torsion spring 11b exceeds the drag force, the hollow shaft 30 and the crankshaft 10 rotate integrally without shifting their phases, and the pedaling force of the pedal 12 causes the sprocket gear 31 and the endless chain 7 to rotate. Is transmitted to the sprocket gear 8 of the rear wheel via the, and the bicycle 1 advances.

When a load operation mode such as starting to climb a slope is entered and the resistance applied to the sprocket gear 31 becomes stronger and exceeds the restoring force of the torsion spring 11b, the crankshaft 10 leads the hollow shaft 30 and rotates in the clockwise direction. It rotates while producing a difference in the rotation phase. Moreover, due to the nature of the spring, the steeper the slope, the greater the difference in rotation. Then, when the drag is weakened after the climb, the crankshaft 10 is returned to the counterclockwise direction by the bias of the torsion spring 11b. In FIG. 20, the symbol L indicates the position where the low gear mode is desired, and the symbol H indicates the position where the high gear mode is desired. In the crank mechanism adopting this double shaft structure, the rotational phase difference between the crank shaft 10 and the hollow shaft 30 responds to the strength of the drag in real time, and this mechanism functions as a drag detecting device. . Therefore, it is possible to detect the rotational phase difference with a sensor and drive the electric motor or the electric actuator in response to the detection signal to expand or contract the crank A, or to change the gear with the motor.

[0064]

According to each of the first to eighth aspects of the present invention, the gear meshing of the transmission is manually changed with respect to the change in the load applied to the bicycle, or the electric motor is insufficient. It does not make up for the amount, but when the forward load exceeds the cruise speed, the turning radius of the pedal automatically increases due to the pedaling force applied to the pedal, and the turning moment increases as the rolling radius of the pedal extends. Therefore, the propulsive force of the bicycle is sufficiently increased without increasing the stepping force more than necessary, and the bicycle can be operated lightly even in the weighted load operation mode.

Further, if the turning radius of either the left or right of the pedal increases, the pedals on the opposite side also have the same turning radius with a 180 ° phase difference, so as long as there is a weighted load on either of the left and right pedals. The pedal position is not excessively shortened, and even if one of the pedals is unloaded, the phase thereof can be maintained and the pedaling operation of the bicycle can be smoothly performed at any time. Furthermore, when the weighted load on the bicycle is removed, the turning radius of the pedal is automatically shortened by the restoring force of the spring member, and the transition between the weighted load mode and the cruise mode is automatically and steplessly performed. It is done smoothly.

In the invention described in claim 2, since the crank expansion / contraction mechanism is composed of one kind of a link mechanism, a gear mechanism, or a combination mechanism thereof, which is extremely common, manufacturing and assembling can be performed at low cost and robustly. It is highly likely.

In the third aspect of the present invention, since the crank expansion / contraction mechanism is of a payout slide type and is connected to the guide link, the structure thereof is extremely simple and simple, and there are few failures. The price is much lower than the electric hybrid type.

In the invention of claim 4, unlike the invention of claim 3, there is no guide link, and the additional parts on the side surface such as the sprocket gear are only the arm sliding guide case and the pedal arm, and the mechanism is simplified. The appearance looks good.

According to the fifth and seventh aspects of the present invention, the pedal arm is a refracting pedal arm having a joint in the middle, and a fan-shaped gear is formed at the base of the tip side arm member. Since the gear is meshed with the arc gear fixed to the side of the sprocket gear and the like, the crank expansion / contraction mechanism does not have a linear motion sliding fit, and the operation is smooth because it is all reciprocating rotary motion.

In the eighth aspect of the invention, since the spring force adjusting mechanism is added to the spring member, the restoring force of the spring member can be adjusted according to the physical strength of the user.

According to the ninth aspect of the invention, a cushioning action is obtained when the crank A contracts, and there is a risk that the radius of gyration of the pedal will be sharply shortened even if the pedal is stepped off in the weighted load mode. Absent.

According to the tenth aspect of the invention, since the damper is formed by the arm sliding guide case and a part of the pedal arm, it is not necessary to separately provide the damper, and the space for assembly and mounting is saved. it can.

According to the eleventh aspect of the present invention, since the damper is housed in the internal space of the tension coil spring, it suffices if there is only a space for the tension coil spring, and the appearance is neat.

[Brief description of drawings]

FIG. 1 is an enlarged side view showing a crank mechanism of a general bicycle.

FIG. 2 is a diagram showing the configuration of the crank mechanism of FIG.

FIG. 3 is a diagram of a crank mechanism in which a turning radius of a pedal is doubled with respect to the crank mechanism of FIG.

FIG. 4 is a schematic plan view of a conventional two-division swing bending / extending pedal arm device.

5 is a side view of the pedal arm device of FIG. 4. FIG.

6 is an operation explanatory diagram showing a state before depressing a pedal in the pedal arm device of FIG. 4. FIG.

7 is an operation explanatory diagram showing a state when the right pedal is depressed in the pedal arm device of FIG. 4. FIG.

8 is an operation explanatory diagram showing a state when the right pedal is rotated to a bottom dead center in the pedal arm device of FIG. 4. FIG.

9 is an operation explanatory diagram showing a state when the left pedal is lifted in the pedal arm device of FIG. 4.

FIG. 10 is a schematic side view of the crank mechanism according to the first embodiment of the present invention.

FIG. 11 is a schematic plan view showing a cross section of a part of the crank mechanism of the first embodiment.

FIG. 12 is a schematic side view of a crank mechanism according to a second embodiment of the present invention.

FIG. 13 is a schematic plan view showing a cross section of a part of the crank mechanism of the second embodiment.

FIG. 14 is a schematic side view of a drag-adaptive automatic expansion / contraction variable type crank mechanism according to a third embodiment of the present invention.

FIG. 15 is a schematic side view of a drag-adaptive automatic expansion / contraction variable-type crank mechanism according to a fourth embodiment of the present invention.

FIG. 16 is a schematic side view of a drag-adaptive automatic expansion / contraction change-type crank mechanism according to a fifth embodiment of the present invention.

FIG. 17 is a partially enlarged side view showing a case where an air damper is formed by a part of an arm sliding guide case and a pedal arm in the sixth embodiment of the present invention.

FIG. 18 is a side view showing a case where a spring force adjusting mechanism is added to a spring member in Embodiment 7 of the present invention.

FIG. 19 is a side view showing a case where an air damper is housed in an internal space of a spring member in Embodiment 8 of the present invention.

FIG. 20 is a schematic perspective view of a crank mechanism according to a ninth embodiment of the present invention.

FIG. 21 is a sectional view of a crankshaft rotation angle regulating mechanism portion in the crank mechanism of the ninth embodiment.

FIG. 22 is a front view of a torsion spring used in the crank mechanism of the ninth embodiment in an unloaded state.

[Explanation of symbols]

10 crankshaft 11 Spring member 12 pedals 13 Arm sliding guide case 14 pedal arm 14a Bendable pedal arm 14b Tip side pedal arm 14c Root side pedal arm 14d connector 15 induction links 16 racks 17 First Pinion 18 pinion shaft 19 Second Pinion 20 joint axes 21 fan gear 22 links 23 links 30 hollow shaft 31 sprocket gear 32 board stay 33 arc gear 35 1st stopper 36 Second stopper 40 frames 41 bearing 45 air damper A crank B crank expansion mechanism C pantograph mechanism

Claims (11)

[Claims] 1. A two-wheeled or three-wheeled human-powered bicycle (hereinafter, simply referred to as a bicycle) whose wheels rotate in a forward direction by depressing a pedal 12, and is a hollow that is slidably fitted on the outer side of a crankshaft 10. A sprocket gear 31 for driving is fixed to one end of the shaft 30, the hollow shaft 30 is supported by a frame 40 of a bicycle via bearings 41, and both ends of the crank shaft 10 are connected to the crank shaft 10. The expansion / contraction type crank A in which the position of the pedal 12 with respect to the center of rotation of the crankshaft is provided with a 180 ° phase difference, and the crankshaft 10 reciprocally rotates within the set angle range with respect to the hollow shaft 30. The crankshaft 10 is freely arranged, and when the rotation direction of the crank A when the bicycle moves forward is the drive rotation direction, the crankshaft 10 is the hollow shaft 3
0 and the crankshaft 10 are urged to rotate in a direction opposite to the drive rotation direction by a spring member 11 provided directly or indirectly. In the cruising operation load mode of the bicycle, the crankshaft 1
While the rotational phase of 0 and the rotational phase of the hollow shaft 30 match, in the weighted load operation mode such as climbing, the spring member 11 is deformed and the rotational phase of the crankshaft 10 and the rotational phase of the hollow shaft 30 are changed. The spring member 11 is set so that there is a difference between the crankshaft 10 and the hollow shaft 30 caused by the stepping force against the weighted load received by the bicycle. Crank expansion / contraction mechanism B for varying the radial position of the pedal 12 with respect to the center of rotation of the crankshaft 10.
A bicycle equipped with a drag-compatible automatic expansion and contraction type crank. 2. A plate-like stay 32, which is parallel to the surface of the sprocket gear 31, is fixed to the other end of the hollow shaft 30, and the sprocket gear 31 and the plate-like stay 32 (hereinafter, both are collectively referred to as a sprocket. The crank A is reciprocally rotatable within a set angle range with respect to a gear 31, etc.), and the phase of the crank A is changed by the stepping force against the weighted load applied to the pedal 12 at the tip of the crank A. The crank A and the sprocket gear 31 and the like are advanced so as to lead the phase of the sprocket gear 31 and the like while resisting the restoring force of the spring member 11 and the crank length is expanded and contracted due to the advance of the crank A. Are connected by a crank expansion / contraction mechanism B, and the crank expansion / contraction mechanism B is a link mechanism, a gear mechanism, or a combination mechanism thereof. Bicycle according to claim 1, characterized in that than one. 3. The expansion / contraction variable type crank comprises an arm slide guide case 13 fixed to both ends of the crank shaft 10 in a radial direction thereof, and a pedal arm 14 sliding therein.
The crank extension mechanism B is configured by a link mechanism having a guide link 15, and one end of the guide link 15 is a tip end of the pedal arm 14 by a pivot 15a parallel to the crankshaft 10. And the other end of the guide link 15 is parallel to the crankshaft 10.
The bicycle according to claim 1 or 2, wherein the crank is pivotally attached to a side surface of the sprocket gear 31 or the like in the vicinity of the leading end of the movable range of the crank A by b. 4. The expansion / contraction variable type crank comprises an arm sliding guide case 13 fixed to both ends of the crank shaft 10 in a radial direction thereof, and a pedal arm 14 sliding therein.
The crank extension mechanism B is supported by a rack 16 formed on a side surface portion of the pedal arm 14 and a portion of the arm slide guide case 13 that is separated from the crankshaft 10. The first pinion 17, the second pinion 19 supported by the arm sliding guide case 13 so as to rotate integrally with the first pinion 17, and the arc gear 33 provided concentrically on the side surface of the precursor sprocket gear 31 and the like. 2. The gear mechanism is composed of, and the rack 16 and the first pinion 17 are meshed with each other, and the arc gear 33 and the second pinion 19 are meshed with each other.
Alternatively, the bicycle according to claim 2. 5. The expansion / contraction variable type crank A is attached to the joint shaft 2.
Bendable pedal arm 14a composed of a tip side pedal arm 14b and a root side pedal arm 14c connected by 0
The fan gear 21 is provided at the root of the tip side pedal arm 14b, and the arc gear 33 is concentrically fixed to the side surface of the sprocket gear 31 and the like.
The bicycle according to claim 1 or 2, wherein the crank expansion mechanism B is constituted by a combination of a link mechanism and a gear mechanism by engaging with the arc gear 33. 6. The crank A is constituted by a pantograph mechanism C which is a kind of link mechanism, and a link 23a of the pantograph mechanism C is fixed to the crankshaft 10.
The other link 23b of the pantograph mechanism C parallel to the link 23a is pivotally attached to the base pedal arm 14c at the base end side by a pivot 26 parallel to the crankshaft 10 to form a crank extension / contraction mechanism B. The bicycle according to claim 1, 2 or 5, wherein a tip end side portion of 23b is the tip end side pedal arm 14b. 7. The crank A includes a front pedal arm 14b, a base pedal arm 14c, and a connector 14d.
And a root portion of the tip side pedal arm 14b is pivotally attached to the root side pedal arm 14c by a pivot 27 parallel to the crankshaft 10.
c is fixed to the hollow shaft 30, and the connector 14
d is fixed to the crankshaft 10, and the fan-shaped gear 21a and the connector 14 at the base end of the tip-side pedal arm 14b.
The bicycle according to claim 1, 2, or 5, wherein the fan-shaped gear 21b at the base end portion of d is meshed with each other, and the crank expansion / contraction mechanism B is a combination of a gear mechanism and a link mechanism. 8. The spring member 11 is one of a torsion spring and a tension coil spring, and is a spring member 1.
The bicycle according to any one of claims 1 to 7, wherein a spring force adjusting mechanism is added to one end of the bicycle. 9. The bicycle according to claim 1, wherein the crank extension mechanism B includes a damper 45 which acts as a buffer when the crank A contracts. 10. The bicycle according to claim 9, wherein a damper 45 is formed by the arm sliding guide case 13 and a part of the pedal arm 14. 11. The spring member 11 is a tension coil spring, one end of which is engaged with the sprocket gear 31 and the like, the other end thereof is engaged with a part of the crank A, and a position separated from the crankshaft 10. The damper 45, which is provided at the bottom of the tension coil spring and acts only when it is shortened.
The bicycle according to claim 10, wherein the coil spring is mounted inside the coil spring 11a.