CN102076554A

CN102076554A - Tandem bicycle

Info

Publication number: CN102076554A
Application number: CN2009801245944A
Authority: CN
Inventors: 崔义正
Original assignee: Individual
Current assignee: Individual
Priority date: 2008-04-25
Filing date: 2009-04-24
Publication date: 2011-05-25
Also published as: KR20090113052A; WO2009131421A2; WO2009131421A3

Abstract

The present invention relates to a tandem bicycle having a front wheel and a rear wheel, a main frame which separates the front wheel and the rear wheel, and a pair of saddles supported by the main frame. The present invention is characterized in that the invention comprises: a main rotational shaft provided in such a way as to be able to rotate on the main frame; a pair of main pedals for making the main rotational shaft rotate; a rear-wheel shaft which is provided in such a way as to be able to rotate on the main frame, and which has the rear wheel mounted on it; a main power-transmission part for transmitting, to the rear-wheel shaft, a rotational force generated at the main rotational shaft; an auxiliary rotational shaft which is positioned between the main rotational shaft and the rear-wheel shaft, and which is provided in such a way as to be able to rotate on the main frame; a pair of auxiliary pedals for making the auxiliary rotational shaft rotate; an auxiliary drive sprocket located on the auxiliary rotational shaft; an auxiliary driven sprocket located on the rear-wheel shaft; an auxiliary chain for transmitting power, which links the auxiliary drive sprocket and the auxiliary driven sprocket with each other; and a one-way clutch which is provided between the auxiliary driven sprocket and the rear-wheel shaft, and which imposes a break in such a way that rotational force from the rear-wheel shaft is not transmitted to the auxiliary driven sprocket. In this way, not only can the machine move as a rider sitting at the rear rotates the pedals as they themselves desire, but also the enjoyment to be had from riding on a bicycle can be multiplied. Additionally, two riders can sit back to back, and can move safely while ascertaining conditions to front and rear.

Description

Tandem bicycle

Technical field

The present invention relates to a kind of tandem bicycle, more specifically, relate to a kind of two rider's individual drive trailing wheels, can make the tandem bicycle of bicycle running.

Background technology

Because of the prosperity of civilization, the modern is considerably less with respect to its amount of exercise of the quantity of food of being absorbed, so population of being obese sharply increases, and we live in the epoch that become topic because of the importance of the health of adult diseases.

The major cause of adult diseases is fat, various diet products occurred in order to reduce body fat, but has been not to develop professionally, so the out of reach expectation far away of its fat-reducing effect.

For the belly of losing weight, use and to utilize electric various electronic waistband, but when standing or seat the time, giving vibration to the part of health is to decompose body fat.Just can feel comfortably cool, and out of reach decomposes the condition of body fat in the moment of using waistband.

Recently, for remove or the savings of losing weight at the body fat of belly, thigh, face etc., popular the channels and collaterals massage that utilizes fine motion, but the fat of only being put aside when the expert massages in the part temporarily is distributed to elsewhere, returns to previous status after a period of time again.

Be not only ordinary people, the expert also lacks the understanding of motion very much, only concentrates the load exercise of tempering muscle power, the sport of this kind short time makes the people endlessly tired, can't move by persistence,, not help decomposing body fat though this load exercise is helpful to muscular movement.

Be aerobic exercise by bike, it is favourable to aerobic exercise, but picture Korea S area is little, even reach on the road of the crowded and traffic jam of 1,700 ten thousand automobile special bike-way is arranged, and also because of the public hazards of automobile, is difficult to guarantee people by bike.This is a reality.

We answer the main force in only using automobile where necessary, guarantee people from basic unit by bike.

Not only will popularize bicycle, be made into safe and interesting utensil to bicycle, this will help guaranteeing people from basic unit.

Recently, popularizing the tandem bicycle that a kind of two people together ride not is the bicycle that a people rides.

Tandem bicycle in the past is that two people exercise towards the place ahead, and the rider who is sitting in the rear is only seeing the back enforcement of preceding dough figurine and is being difficult to watch attentively the place ahead, compares with general bicycle, and the whole length of bicycle is long, be difficult to observe the rear, therefore make the rider feel uneasy and dangerous.

So, utilize tandem bicycle in the past to travel on Ordinary road, the danger that invariably accompanies, therefore almost nobody buys tandem bicycle and can not get practicability, only temporarily looks for enjoyment to play in the field that safety such as park have been guaranteed by borrowing or lending money.

And tandem bicycle in the past is, when bicycle running, the rider who rides over the rear can not the individual drive trailing wheel, irrespectively makes the pedal rotation with oneself intention, and therefore, not only fatigue strength increases but also feels bored again, reduces the interest to motion.

Summary of the invention

Problem to be solved is in the problem of described background technology, and a kind of tandem bicycle is provided, and when the rider who rides over the rear can move according to the intention rotation pedal of oneself, enjoyment by bike also doubled to increase.

Another problem to be solved is in the problem of described background technology, and a kind of tandem bicycle is provided, and two rider's phase backrests can be guaranteed the situation at the place ahead and rear in the limit by bike, moves safely in the limit.

The solution of described problem is, a kind of tandem bicycle is provided, and it possesses: front-wheel and trailing wheel; Main car frame, it isolates described front-wheel and described trailing wheel; A pair of vehicle seat is supported on described main car frame, it is characterized in that: comprising: main rotating shaft, and described main car frame is located in its rotation freely; A pair of main pedal, it makes described main rotating shaft rotation; Hind axle, described main car frame is located in its rotation freely, and described trailing wheel is installed; Active force reception and registration portion, it passes on the rotational force that takes place from described main rotating shaft to described hind axle; The subsidy S. A., it is between described main rotating shaft and described hind axle, and described main car frame is located in rotation freely; A pair of subsidy pedal, it makes described subsidy S. A. rotation; The subsidy drive sprocket, it is disposed at described subsidy S. A.; Subsidy is by movable sprocket, and it is disposed at described hind axle; The subsidy chain, its be connected described subsidy drive sprocket and described subsidy are used to pass on power by movable sprocket; Free-wheel clutch, it is located at described subsidy by between movable sprocket and the described hind axle, and the rotational force that limits described hind axle is communicated to described subsidy by movable sprocket.

Described free-wheel clutch comprises: wheel hub, and it is installed on described hind axle; Card ends wheel, and week forms a plurality of fastening grooves within it, makes to become concentric with described wheel hub freely along the periphery rotation of described wheel hub, and is located at described subsidy by the interior week of movable sprocket; A plurality of locking protrusions, it rotates and to be located at described wheel hub freely, by being ended at described fastening groove by card or removing described card and end, described hind axle is just changeed or dallies; A plurality of springs, it provides elastic force to described locking protrusion to make described locking protrusion be blocked only at described fastening groove.

Further comprise: clutch case, it holds described free-wheel clutch; A plurality of balls, it is located at described clutch case and described card ends between the wheel, makes described card end the wheel rotation and is supported on described clutch case freely.

Described subsidy chain is located at described subsidy drive sprocket and described subsidy by movable sprocket with criss-cross.

Described active force reception and registration portion comprises: main drive sprocket, and it is installed on described main rotating shaft; Main by movable sprocket more than one, it is installed on described hind axle; The main chain bar connects described main drive sprocket and described master by one in the movable sprocket, passes on the rotational force that takes place from described main rotating shaft to described hind axle.

Described passive sprocket wheel is formed with a plurality of, and is described respectively different by the diameter of movable sprocket, thereby but multi-change speed makes the rotation number of described trailing wheel can be adjusted into various kinds.

Described vehicle seat possesses: the buttocks support portion, and it supports rider's buttocks; Protrusion, outstanding from described buttocks support portion, be configured between rider's the two legs, each buttocks support portion of described a pair of vehicle seat is faced mutually, and is supported in described main car frame, thereby, two rider's phase backrests can be guaranteed the situation at the place ahead and rear in the limit by bike, move safely in the limit.

Therefore, according to the solution of described problem, when the rider who rides over the rear can move according to the intention rotation pedal of oneself, enjoyment by bike also doubled to increase.And two rider's phase backrests can be guaranteed the situation at the place ahead and rear in the limit by bike, move safely in the limit.

Description of drawings

Fig. 1 is the oblique drawing according to tandem bicycle of the present invention.

Fig. 2 is the front elevation of Fig. 1.

Fig. 3 is the back view of Fig. 1.

Fig. 4 is the plan view of Fig. 1.

Fig. 5 and Fig. 6 are the section drawings of operating state that the free-wheel clutch of Fig. 1 is shown.

Among the figure:

11: front-wheel, 17: main handle, 21: trailing wheel, 23: hind axle, 25: main car frame, 33a, 33b: vehicle seat, 35: buttocks support portion, 37: protrusion, 41: main rotating shaft, 45: main pedal, 53a: main drive sprocket, 53b: main by movable sprocket, 55: main chain bar, 71: subsidy S. A., 73: the subsidy pedal, 75a: subsidy drive sprocket, 75b: subsidize by dynamic clutch 77: subsidy chain, 81: free-wheel clutch, 83: wheel hub, 85: card ends wheel, 87: fastening groove, 89: locking protrusion, 91: spring, 93: clutch case, 95: ball

The specific embodiment

Below, present invention will be described in detail with reference to the accompanying.

Fig. 1 and even Fig. 4 represent according to tandem bicycle of the present invention.As shown in the figure,, comprising according to tandem bicycle of the present invention: front-wheel 11, it is handled by main handle 17; Trailing wheel 21, its rotational force by main pedal 45 and subsidy pedal 73 is rotated; Main car frame 25, front-wheel 11 and trailing wheel 21 are supported in its rotation freely.

Central authorities at front-wheel 11 connect front wheel spindle 13, and front wheel spindle 13 rotations are supported in front wheel carrier 15 freely.

Top at front wheel carrier 15 disposes the main handle 17 that is used to handle front-wheel 11, at main handle 17 a pair of handle 19 that can grip is set.

Trailing wheel 21 and front-wheel 11 compartments are every configuration, and at central authorities' connection hind axle 23 of trailing wheel 21, hind axle 23 rotations are supported in main car frame 25 freely.

Main car frame 25 is the truss structure that connects front-wheel 11 and trailing wheel 21.The main car frame 25 that is positioned at front-wheel 11 tops is provided with the anchor shaft 27 that front wheel carrier 15 connects.

But the upside of the main car frame 25 between front-wheel 11 and trailing wheel 21 be provided with for two riders mutually backrest ride a pair of vehicle seat 33a, the 33b of seat.Each

vehicle seat

33a, 33b comprise: arch buttocks support portion 35, and it cosily supports the buttocks of rider's ischium part; Protrusion 37, it is 35 outstanding extensions from the buttocks support portion, are configured between rider's the two legs.Practise physiognomy and dispose over the ground in the buttocks support portion 35 of each

vehicle seat

33a, 33b, simultaneously, the protrusion 37 of each

vehicle seat

33a, 33b is disposed towards the mode of main handle 17 with subsidy handle 101 described later.Thus, two rider's backrests are sitting in each

vehicle seat

33a, 33b.

Main car frame 25 rotations between front-wheel 11 and trailing wheel 21 are provided with main rotating shaft 41 freely, and this main rotating shaft 41 is by main pedal 45 rotations.

Both side ends at main rotating shaft 41 connects a pair of main pedal 45, and it is used to make main rotating shaft 41 rotations.

In addition, main rotating shaft 41 is connected by active force reception and registration portion with hind axle 23.Active force reception and registration portion comprises: main drive sprocket 53a, and it is installed on main rotating shaft 41; A plurality of masters are by movable sprocket 53b, and it is installed on hind axle 23; Main chain bar 55 connects main drive sprocket 53a and a plurality of master by one among the movable sprocket 53b, passes on the rotational force that takes place from main rotating shaft 41 to hind axle 23.

Make to be same plane, each head sprocket 53a, 53b are installed on a side end of main rotating shaft 41 and hind axle 23.

Especially, a plurality of master is neither with so that the rotation number by operation variable-speed unit speed change trailing wheel 21 described later by the diameter of movable sprocket 53b.

Herein, the diameter of main drive sprocket 53a is preferably main big by the diameter of movable sprocket 53b than each.

Thus, active force reception and registration portion is conveyed to hind axle 23 with the rotational force of main rotating shaft 41, thereby trailing wheel 21 has the driving function.

In addition, further possesses known bicycle shift unit according to tandem bicycle of the present invention, at main handle 17 variable speed operation portion 63 is installed, configuration shifter bar 65 on the swing-around trajectory of main chain bar 55, this shifter bar optionally hangs over a plurality of masters by one among the movable sprocket 53b with main chain bar 55, and shifter bar 65 is connected by shift cable 67 with variable speed operation portion 63.

Thus, operation variable speed operation portion 63 makes that shift cable 67 is nervous or relaxes in main chain bar 55 rotation, and then shift cable 67 is nervous or relax shifter bars 65, thereby main chain bar 55 optionally is hung in the mutually different a plurality of masters of diameter by one in the movable sprocket 65.Promptly, as the one example, draw the shift cable 67 that is connected in shifter bar 65 to make 55 rotations of main chain bar, then be hung in a plurality of masters and become low speed by movable sprocket 53b by the master that diameter is big relatively among the movable sprocket 53b, thereby trailing wheel 21 is to rotate than normal rotative speed low velocity, untie shift cable 67 and make 55 rotations of main chain bar, then be hung in a plurality of masters and become at a high speed by movable sprocket 53b, thereby trailing wheel 21 is to rotate at a high speed than normal rotative speed by the master that diameter is relatively little among the movable sprocket 53b.Variable-speed unit can optionally be installed herein.

In addition, according to tandem bicycle of the present invention, configuration subsidy S. A. 71 between main rotating shaft 41 and hind axle 23, main car frame 25 is located in 71 rotations of subsidy S. A. freely.

Both side ends at subsidy S. A. 71 connects a pair of subsidy pedal 73 that is used to make 71 rotations of subsidy S. A..

Subsidy drive sprocket 75a and subsidy are set by movable sprocket 75b respectively at subsidy S. A. 71 and hind axle 23.Each is subsidized

sprocket wheel

75a, 75b and main drive sprocket 53a and master and is the end side of same Plane Installation at subsidy S. A. 71 and hind axle 23 by movable sprocket 3b compartment.Herein, subsidy drive sprocket 75a and subsidy are preferably had same diameter by movable sprocket 75b.

Subsidy drive sprocket 75a and subsidy are connected by subsidy chain 77 by movable sprocket 75b, and subsidy chain 77 is passed on the rotational force that takes place from subsidizing S. A. 71 to hind axle 23.Herein, subsidy chain 77 preferably hangs over subsidy drive sprocket 75a and subsidy by movable sprocket 75b with criss-cross, therefore subsidize drive sprocket 75a with subsidy by movable sprocket 75b always to same direction rotation.

In addition, be provided with free-wheel clutch 81 between subsidy drive sprocket 75a and hind axle 23, the rotational force of free-wheel clutch 81 restriction hind axles 23 is communicated to subsidy by movable sprocket 75b.

Shown in Fig. 5 and 6, free-wheel clutch 81 comprises: wheel hub 83, and it is installed on hind axle 23; Card only takes turns 85, and week forms a plurality of fastening grooves 87 within it, and is located at subsidy by the interior week of movable sprocket 75b; A plurality of locking protrusions 89, its card end at fastening groove 87 or remove described card and end; A plurality of springs 89, it provides elastic force to locking protrusion 89 to make by card only at fastening groove 87.

Wheel hub 83 spiral shells are tied in hind axle 23, and at the interior axle formation left-handed screw of wheel hub 83, it preferably breaks away from from hind axle 23 when bicycle running so that prevent with hind axle 23 spiral shells knot.

It is 85 concentric with 83 one-tenths of wheel hubs so that rotate along the periphery of wheel hub 83 that card is only taken turns, and blocks only to take turns 85 and be located at subsidy by the interior week of movable sprocket 75b.Card in the present embodiment only take turns 85 with the subsidy formed as one by movable sprocket 75b.

Only take turns at card 85 interior week form a plurality of fastening grooves 87, be used to make the locking protrusion card to end or remove described card and end.A plurality of each fastening groove 87 are only taken turns interior all wiring of 85 to the rear of bicycle to card and are predetermined angular, only take turns 85 be recessed to form with predetermined distance in interior week along card.

Locking protrusion 89 rotates and is linked in wheel hub 83 freely, and an end of locking protrusion 89 is only blocked only takes turns 85 fastening groove 87 at card and maybe can remove card and only take turns the card of 85 fastening groove 87 and end, thereby, hind axle 23 is just being changeed and dally.In the present embodiment, only disclose a pair of locking protrusion 89, but the quantity of locking protrusion 89 is not limited thereto.

Locking protrusion 89 by spring 91 resilient mountings so that provide elastic force to be blocked only at fastening groove 87.

Comprise that described wheel hub 83, card only take turns 85, the free-wheel clutch 81 of the formation of locking protrusion 89, spring 91 is contained in clutch case 93.

Only take turns between 85 at clutch case 93 and card, promptly the medial surface of clutch case 93 is only taken turns between 85 the lateral surface with card a plurality of balls 95 is set, and this ball will block only takes turns 85 and rotate and be supported in clutch case 93 freely.

And, according to tandem bicycle of the present invention, further possess subsidy handle 101, in bicycle running, can stably keep the center for the rider who rides over the rear.

Subsidy handle 101 possesses the handle 103 that can grip, and subsidy handle 101 symmetrically is fixed on main car frame 25 every middle with main handle 17 with a pair of

vehicle seat

33a, 33b.

And tandem bicycle according to the present invention possesses: Brake lever 105, and it is used for the driving of braking rear-wheel 21; Brake facing 107; Brake cable 109.

Brake lever 105 is installed on main handle 17, and brake facing 107 is contacted with the side of trailing wheel 21 or leaves from the side of trailing wheel 21, and Brake lever 105 can be connected by brake cable 109 with brake facing 107.

Thus, by operation Brake lever 105 nervous or mitigation brake cable 109, brake facing 107 is left with the contacts side surfaces of trailing wheel 21 or from the side of trailing wheel 21, thereby adjust the friction force between brake facing 107 and the trailing wheel 21, the driving of braking rear-wheel 21 simply.

By described formation, the use of the tandem bicycle according to the present invention is described.

Two riders phase backrest respectively are sitting in

vehicle seat

33a, 33b, this vehicle seat is located at the front and back of bicycle, under this state, the rider who rides over bicycle the place ahead steps on main pedal 45 rotations to the direct of travel of bicycle, then the rotational force of the main rotating shaft 41 of the rotation by main pedal 45 is communicated to hind axle 23 by main chain bar 55, thereby hind axle 23 is to the direct of travel rotation of bicycle, and bicycle carries out forward movement thus.

Ride over the direct of travel of the rider of bicycle rear in addition to oneself, promptly step on 73 rotations of subsidy pedal to the reversing sense of the rider's who rides over bicycle the place ahead direct of travel, then pass through the rotational force process subsidy drive sprocket 75a of the subsidy S. A. 71 of subsidy pedal 73 rotations, be communicated to subsidy by movable sprocket 75b by the subsidy chain, thus, subsidy is by the working direction rotation of movable sprocket 75b to bicycle.

At this moment, rotated to the direct of travel of bicycle by movable sprocket 75b by subsidy, the card of free-wheel clutch 81 is only taken turns the 85 direct of travel rotations to bicycle, promptly for convenience of description, as shown in Figure 5, card only takes turns 85 to the anticlockwise direction rotation, and the locking protrusion 89 of bicycle is only only taken turns 85 fastening groove 87 at card by card, card is only taken turns 85 and rotate to same direction with wheel hub 83 thus, and the hind axle 23 that connects with wheel hub 83 rotates to the direct of travel of bicycle.

Thereby, two riders phase backrest respectively are sitting in

vehicle seat

33a, 33b, this vehicle seat is located at the front and back of bicycle, under this state, two riders step on

main pedal

45 and 73 rotations of subsidy pedal simultaneously to the direct of travel of oneself respectively, then occur in main pedal 45 respectively and be communicated to hind axle 21 simultaneously, thereby increase the speed of bicycle with the rotational force of subsidizing pedal 73.

In addition, the rider who rides over bicycle the place ahead steps on main pedal 45 rotations to the direct of travel of oneself, and the rider who rides over bicycle rear is not when stepping on the rotation of subsidy pedal 73, the only rotational force rotation by taking place at main pedal 45 of trailing wheel 21, the bicycle motion of advancing.

At this moment, the rotational force that takes place at trailing wheel 21 can't be communicated to subsidy by movable sprocket by free-wheel clutch 81.Promptly, trailing wheel 21 rotates to the direct of travel of bicycle by the rotation of main pedal 45, the wheel hub 83 of free-wheel clutch 81 and the trailing wheel 23 1 working direction rotation of bicycle in the same way, then as shown in Figure 6, when hind axle 23 and wheel hub 83 when anticlockwise direction rotates, locking protrusion 89 can't only only be taken turns 85 fastening groove 87 by card at card, thus, hind axle 23 and wheel hub 83 are only taken turns 85 interior Zhou Jinhang idle running along card.

Thereby, card only take turns 85 with subsidy by movable sprocket 75b to the rotation of the direct of travel of bicycle and keep halted state, so the rotational force of hind axle 23 can't be communicated to subsidy by movable sprocket 75b.

Therefore, but subsidy pedal 73 and main pedal 45 independent drive, the rider who rides over the rear can make subsidy pedal 73 rotate when moving according to the intention of oneself, and enjoyment by bike also doubles to increase.

According to tandem bicycle of the present invention, two riders phase backrest respectively are sitting in

vehicle seat

33a, 33b, this vehicle seat is located at the front and back of bicycle, under this state, by stepping on

main pedal

45 and 73 rotations of subsidy pedal, thereby but two rider's phase backrests are stepped on

plate

45,73 to direct of travel separately, but, can be by the main handle 17 of operation only to a direction running, can guarantee the back situation by the back dough figurine that the backrest seat, can freely talk with the rider who forwards exercises, notify the back situation sometimes, can be joyously by bike.

And, the rider who rides over the rear is broken the fixed idea that bicycle is only forwards exercised, joyously by bike, and the prevention adult diseases, take exercises.

In addition, the active force reception and registration portion as main rotating shaft and hind axle that illustrated among the described embodiment possesses main drive sprocket, master are passed on the rotational force of main pedal by movable sprocket and main chain bar example, but, at main rotating shaft and hind axle a pair of belt wheel is installed, each belt wheel connects by band, and the rotational force with main rotating shaft is conveyed to trailing wheel thus.

Illustrated among the described embodiment at subsidy S. A. and hind axle and possessed the subsidy drive sprocket and subsidize by movable sprocket and subsidy chain, thereby the rotational force that will subsidize pedal is conveyed to the example of hind axle, but, between main rotating shaft and subsidy S. A., a pair of belt wheel is installed, each belt wheel connects by band, and the rotational force that will subsidize S. A. thus is conveyed to main rotating shaft.

Illustrated among the described embodiment that a plurality of masters are installed in the example of hind axle by movable sprocket, still, also can only install a master by movable sprocket at hind axle.

Although illustrated and described the preferred embodiments of the present invention, it is contemplated that those skilled in the art can design various modifications of the present invention in thought of the present invention and scope.Those variation or modification are interpreted as belonging in the claim scope of the present invention.

Claims

1. tandem bicycle, it possesses: front-wheel and trailing wheel; Main car frame, it isolates described front-wheel and described trailing wheel; A pair of vehicle seat, it is supported on described main car frame, it is characterized in that: comprising:

Main rotating shaft, described main car frame is located in its rotation freely;

A pair of main pedal, it makes described main rotating shaft rotation;

Hind axle, described main car frame is located in its rotation freely, and described trailing wheel is installed;

Active force reception and registration portion, it passes on the rotational force that takes place from described main rotating shaft to described hind axle;

The subsidy S. A., it is between described main rotating shaft and described hind axle, and described main car frame is located in its rotation freely;

A pair of subsidy pedal, it makes described subsidy S. A. rotation;

The subsidy drive sprocket, it is disposed at described subsidy S. A.;

Subsidy is by movable sprocket, and it is disposed at described hind axle;

The subsidy chain, its be connected described subsidy drive sprocket and described subsidy are used to pass on power by movable sprocket;

Free-wheel clutch, it is located at described subsidy by between movable sprocket and the described hind axle, and the rotational force that limits described hind axle is communicated to described subsidy by movable sprocket.

2. tandem bicycle according to claim 1 is characterized in that:

Described free-wheel clutch comprises:

Wheel hub, it is installed on described hind axle;

Card ends wheel, and week forms a plurality of fastening grooves within it, makes to become concentric with described wheel hub freely along the periphery rotation of described wheel hub, and is located at described subsidy by the interior week of movable sprocket;

A plurality of locking protrusions, it rotates and to be located at described wheel hub freely, by being ended at described fastening groove by card or removing described card and end, described hind axle is just changeed or dallies;

A plurality of springs, it provides elastic force to described locking protrusion to make described locking protrusion be blocked only at described fastening groove.

3. tandem bicycle according to claim 2 is characterized in that, further comprises:

Clutch case, it holds described free-wheel clutch;

A plurality of balls, it is located at described clutch case and described card ends between the wheel, makes described card end the wheel rotation and is supported on described clutch case freely.

4. tandem bicycle according to claim 1 is characterized in that:

5. tandem bicycle according to claim 1 is characterized in that:

Described active force reception and registration portion comprises:

Main drive sprocket, it is installed on described main rotating shaft;

Main by movable sprocket more than one, it is installed on described hind axle;

The main chain bar connects described main drive sprocket and described master by one in the movable sprocket, passes on the rotational force that takes place from described main rotating shaft to described hind axle.

6. tandem bicycle according to claim 5 is characterized in that:

Described passive sprocket wheel is formed with a plurality of, and is described respectively different by the diameter of movable sprocket.

7. according to each described tandem bicycle in the claim 1 to 6, it is characterized in that:

Described vehicle seat possesses:

The buttocks support portion, it supports rider's buttocks;

Protrusion, outstanding from described buttocks support portion, be configured between rider's the two legs,

Each buttocks support portion of described a pair of vehicle seat is faced mutually, is supported on described main car frame.