CN101590891B

CN101590891B - Oscillating spring bicycles with unequal wheel diameters

Info

Publication number: CN101590891B
Application number: CN2009100317133A
Authority: CN
Inventors: 刘极峰; 杨小兰
Original assignee: Nanjing Institute of Technology
Current assignee: Nanjing Institute of Technology
Priority date: 2009-07-10
Filing date: 2009-07-10
Publication date: 2010-12-01
Anticipated expiration: 2029-07-10
Also published as: CN101590891A

Abstract

The swing spring bicycle with unequal wheel diameters of the present invention relates to a human-driven bicycle device, especially a two-wheel and three-wheel human-driven bicycle device. It is composed of frame part, seat part, control part and driving part; the frame part includes swing shaft front support, swing shaft rear support, upper slant beam, lower slant beam, front fork cover, left spring cover, right spring cover, The rear axle frame, the center axle sleeve and the seat cover; the seat part includes the seat and shock absorber; the control part includes the handlebar, front brake, rear brake, front fork and front wheel; the driving part includes the left swing bar, right swing Rod, left pedal, right pedal, left rope chain, right rope chain, left flywheel, right flywheel, left spring, right spring, sprocket, chain and flywheel; On the axle fork, the rear wheel is installed on the rear axle, the upper part of the rear wheel is equipped with a rear fender, the rear brake is installed on the left side of the rear axle, and the flywheel is installed on the right side of the rear axle. The sprocket drives the flywheel through the chain to drive the movement of the rear wheel , to drive the vehicle forward.

Description

Swing spring type bicycle with different wheel diameters

Technical field

Swing spring type bicycle with different wheel diameters of the present invention relates to is that a kind of manpower drives bicycle device, particularly two takes turns, the three-wheel manpower drives bicycle device.

Background technology

Existing manpower drive bicycle have two take turns, tricycle, all rely on both feet to make it to advance as circular movement downwards, be called ordinary bicycle.It is s=2 π r (r is the pedal radius of turn) that pedal turns back the distance of being passed by that circles along pin, and the merit of being done then is w=Fr (F is the component of power on the round tangential direction along pedal that pin is executed).As seen, the people is in ordinary bicycle is driven process, and most of power all is not utilized, and has only small part power (about 1/3) to make useful work.

Summary of the invention

The objective of the invention is at above-mentioned weak point, swing spring type bicycle with different wheel diameters is provided, be that the flat manpower of pedaling of a kind of double pendulum bar wig-wag spring formula rope-chain drive low-seat drives bicycle, this Che Nengneng increases useful work, reduces idle work, make full use of human body each side energy, realize the purpose of efficient high-speed.The present invention compares with the ordinary bicycle device: laborsaving when speed is identical, and speedup when the application of force is identical.

Swing spring type bicycle with different wheel diameters is to take following technical scheme to realize: swing spring type bicycle with different wheel diameters is made up of vehicle frame part, vehicle seat part, actuating element and drive part.

Vehicle frame partly comprises the preceding support of balance staff, balance staff back brace, goes up cant beam, lower inclined beam, front fork cover, left spring cover, right spring cover, rear axle support, bottom bracket axle and Saddle cover etc.; Last cant beam and lower inclined beam front end are equipped with the front fork cover, support and the balance staff back brace before being connected with balance staff on last cant beam top, support is connected with handlebar grip mutually with balance staff back brace upper end before the balance staff, bottom bracket axle is equipped with at the vehicle frame middle part, Saddle cover is equipped with on bottom bracket axle top, support front end and last cant beam, lower inclined beam Joint, the support rear end with support, the axis diagonal brace is connected, support upper end axis diagonal brace and Saddle cover Joint; Saddle cover links to each other with rear axle support by the back diagonal brace, and the rear axle support front end links to each other with bottom bracket axle, and the rear axle support rear end is provided with the back yoke.Left side spring cover overlaps the lower inclined beam and arranged on left and right sides that is fixed on vehicle frame respectively by the short support of support and spring before the spring with right spring.

Vehicle seat partly comprises vehicle seat and bumper etc., and vehicle seat links to each other with vehicle frame by the vehicle seat inserted link of its lower end, can adjust vehicle seat height up and down by regulating bolt, and vehicle seat is made up of seat cushions, backrest, vehicle seat inserted link.Bumper is equipped with in the seat cushions bottom, and the vehicle seat inserted link is equipped with in the bumper lower end.Bumper is made up of by bolted connection two leaf springs with cavity shapes plate.

Actuating element comprises handlebar, front brake, rear brake, front fork and front-wheel etc.; Front fork is contained in the anterior front fork cover of vehicle frame, and front-wheel is equipped with in the front fork bottom, and front fender apron is housed on the front-wheel, handlebar is contained in the vehicle frame front upper part front fork cover, and front fork is connected with handlebar by the front fork nut, and handlebar rotates and passes through front fork, make front-wheel rotate, and change the travel direction of bicycle.

Front brake is contained in the front fork front end, is used to the front-wheel of stopping, and rear brake is contained on the rear axle, is used to the trailing wheel of stopping, and brake is being contained in the handlebar left and right sides.

Drive part comprises that left fork, right fork, left foot are pedaled, right pedal, Zuo Shenglian, right rope chain, left flywheel, right flywheel, left spring, right spring, sprocket wheel, chain and flywheel.The fork axle is contained in the fork axle sleeve, left side fork is contained in fork axle left side, right fork is contained in fork axle right side, a left side fork and right fork bottom are equipped with respectively that left foot is pedaled, right pedal, left foot is pedaled and is connected with left side rope chain, right rope chain on axle, the right pedal axle respectively, Zuo Shenglian, right rope chain are connected with left spring, right spring by left flywheel, right flywheel respectively, and left spring, right spring are contained in respectively in left spring cover, the right spring housing, can adjust the spring tightness by setting nut.Axis is contained in the bottom bracket axle, and left flywheel is equipped with in the axis left side, and right flywheel is equipped with on the axis right side, and left flywheel, right flywheel are realized coplane respectively with left side rope chain, right rope chain and left spring, right spring, promptly in same plane.

Rear axle is contained in the rear axle that the rear axle support rear end is provided with and sticks, and trailing wheel is contained on the rear axle, and rear mudguard is equipped with on trailing wheel top, and the back brake is equipped with in the rear axle left side, and flywheel is equipped with on the rear axle right side, and sprocket wheel drives flywheel by chain, drives rear wheel movement, drives car load and advances.

Described rear axle and rear axle are stuck support are housed, and are used to support car load.

Described left side rope chain is to adopt the special-purpose hoop that connects to be connected by steel rope and roller chain with right rope chain, the portion of chain of Zuo Shenglian and right rope chain is meshed with left and right flywheel, the other end links with the spring that is contained in the spring housing, each one sealing messenger chain about constituting respectively.Left side flywheel, right flywheel are contained in the vehicle frame both sides of axis respectively, and overriding clutch is housed respectively in it, and be identical with the flywheel of ordinary bicycle, and it can only unidirectionally be turned round.Above sprocket wheel, be equipped with can before and after up-down adjustment, the band backrest the low level vehicle seat.Sprocket wheel drives flywheel by chain and realizes unidirectional rotation, and then advances by hind axle driving trailing wheel and front-wheel.

Described front-wheel and trailing wheel adopt the different wheel diameters design, and preceding wheel diameter is less than the back wheel diameter.

Principle of work: when a left side (or right) pin forward the application of force pedal when stepping on left foot and pedaling, pedal drives left flywheel by left side pendulum swing rod and is rotated in the forward, by axis sprocket wheel drive rear flywheel, trailing wheel are rotated in the forward, bicycle is travelled forward, when left foot is pedaled to the most preceding, spring in the left spring cover is pulled to maximum position, when left foot retreats, will automatically resets at spring force effect bottom left fork; When right crus of diaphragm forward the application of force pedal when stepping on right pedal, situation is similar.When both feet take turns to drive, conversion left and right sides pin, but travelling forward continuously of implement device then.

Above-mentioned rope chain drives and is first order transmission, and second stage chain-driving is then identical with ordinary bicycle.The speedup transmitting ratio i of two-stage transmission can be basic identical, and then overall gear ratio is 2i, is the twice of ordinary bicycle transmitting ratio, steps in identical pedaling that the speed of a motor vehicle can be enhanced about more than once under the frequency.

Principal feature of the present invention has:

1, adopt the secondary chain-driving of double pendulum bar-rope chain and sprocket-rear flywheel:

The driving of existing common two wheel bicycles, cyclo is that people's both feet are pedaled and stepped on pedal and as gyroscopic movement car is advanced, adopt the secondary chain drive mechanism of double pendulum swing rod, its gordian technique is the circular movement of pedal is changed into the movement in a curve that is bordering on straight line.The first order transmission left and right sides mutually noninterfere of double pendulum swing rod can drive simultaneously, but independent drive or double-legged driven again.

2, front and rear wheel adopts the different wheel diameters design, front-wheel is less than trailing wheel, the following problem of main consideration: (1) fork axle amplitude of fluctuation is bigger, when being swung forwards to end position, foot-operated can not colliding with front-wheel and front-wheel guard shield, (2) guarantee that simultaneously front fork axis angle of assembling meets national sector standard, make that handlebar turns to flexibly, safety.

3, adopt low level vehicle seat band backrest structure:

Present two take turns, the tricycle seat is above pedal, when the driver steps pedal downwards, applied force generally can not surpass the weight of self, but when riding racing car, need waist is stooped, scrunch downwards with pin, just can use bigger strength, according to this principle, the vehicle seat of apparatus of the present invention be contained in the contour substantially angular plane surface of pedal on, allow portrait half recumbency equally go forth to pedal and step on pedal near horizontal direction, lean against arcuate backrest simultaneously and can give full play to the application of force principle of human factor engineering, on pedal, need not exert oneself more like this, just can improve speed per hour more than 1 times, as shown in Figure 1.

4, adopt speed changing structure: sprocket wheel-rear flywheel adopts speed changing structure, divides some retainings to carry out speed change, and is with low-grade, very laborsaving when realizing beginning to drive with climbing; Motion is progressively changed top grade after getting up, and adds the effect of inertia under the high-speed motion state, and required propulsive effort is reduced.Low speed when promptly realizing beginning to start-approximate geometric ratio transmission with climbing; High speed during proper motion-big over-speed gear ratio transmission.

5, summary: the present invention takes turns with existing common two, tricycle is compared, and has the following advantages:

1) double pendulum swing rod transmission drive: make the harmful component in the Manpower driver significantly reduce, useful component significantly improves, and further improves driver's endurance and work doing efficiency again, has improved the kinematic velocity of system.

2) low level vehicle seat band backrest structure: make Manpower driver can bring into play the firmly function of organization of human body to greatest extent, reduce people's strength at repeated alternation, strengthen driver's traveling comfort, improve driver's endurance, make its easily drive system advance.

3) adopt speed changing structure: sprocket wheel-rear flywheel adopts outer speed change of cone pulley or rear axle internal speed-changing structure, divides some retainings to carry out speed change, and the low speed in the time of can realizing beginning to start with climbing-approximate geometric ratio transmission makes that required propulsive effort obviously reduces when starting, and is easy to start.

4) consider unit frame, selecting for use of light-duty plastic, the failure-free brake system, the stability that starting is stopped etc., can make two taking turns of adopting that inventor's force driving device makes, tricycle (hermetic type or open type) all can be used as people rides instead of walk, transportation, the vehicle, also can be used as physical culture, recreation and body-building instrument.

Description of drawings

The invention will be further described below with reference to accompanying drawing:

Fig. 1 is the swing spring type bicycle with different wheel diameters front view.Main position, the annexation of expressing vehicle seat, actuating element and drive part comprises front-wheel 1, front axle 2, front fender apron 3, front fork 4, handlebar 5, fork axle 6, vehicle frame 7, right rope chain 8, vehicle seat 9, bumper 10, axis 11, trailing wheel 12, rear axle 13, flywheel 14, rear mudguard 15, support 16, right flywheel 17, left flywheel 18.

Fig. 2 is the swing spring type bicycle with different wheel diameters birds-eye view.Main position, the annexation of expressing drive part left and right sides transmission device comprises that left fork 19, left foot pedal 20, left spring 21, left side rope chain 22, right spring 23, left foot pedal 24, right fork 25, sprocket wheel 26, chain 27.

Fig. 3 is the vehicle frame scheme drawing of swing spring type bicycle with different wheel diameters.Main position, the annexation of expressing each parts of vehicle frame part comprises front fork cover 7-1, pendulum axle sleeve 7-2, balance staff back brace 7-3, goes up cant beam 7-4, support 7-5, Saddle cover 7-6, back diagonal brace 7-7, back yoke 7-8, rear axle support 7-9, bottom bracket axle 7-10, axis diagonal brace 7-11, supports support 7-18 before support 7-16, lower inclined beam 7-17 before 7-12, the short support of spring 7-13, left spring cover 7-14, right spring cover 7-15, the spring, the balance staff.

The specific embodiment

With reference to accompanying drawing 1～3, the embodiment of swing spring type bicycle with different wheel diameters of the present invention adopts the transmission of double pendulum bar swing spring homing position type rope chain secondary, the different wheel diameters that the little rear wheel of front vehicle wheel is big, the bicycle that the low bit strip backrest structure of vehicle seat employing is made for driving.

Swing spring type bicycle with different wheel diameters is made up of vehicle frame 7, vehicle seat 9, actuating element and drive part.

Vehicle frame 7 supports 7-18, balance staff back brace 7-3 before comprising balance staff, upward cant beam 7-4, lower inclined beam 7-17, front fork cover 7-1, left spring overlap 7-14, right spring cover 7-15, rear axle support 7-9, bottom bracket axle 7-10 and Saddle cover 7-6; Last cant beam 7-4 and lower inclined beam 7-17 front end are equipped with front fork cover 7-1,7-18 and balance staff back brace 7-3 are supportted before being connected with balance staff in last cant beam 7-4 top, support 7-18 is connected with handlebar grip 7-2 mutually with balance staff back brace 7-3 upper end before the balance staff, bottom bracket axle 7-10 is equipped with at vehicle frame 7 middle parts, bottom bracket axle 7-10 is equipped with Saddle cover 7-6 in top, support 7-5 front end and last cant beam 7-4, lower inclined beam 7-17 Joint, support 7-5 rear end with support 7-12, axis diagonal brace 7-11 is connected, support 7-5 upper end axis diagonal brace 7-11 and Saddle cover 7-6 Joint.

Saddle cover 7-6 links to each other with rear axle support 7-9 by back diagonal brace 7-7, and rear axle support 7-9 front end links to each other with bottom bracket axle 7-10, and rear axle support 7-9 rear end is provided with back yoke 7-8.Left side spring cover 7-14 and right spring cover 7-15 are fixed on the lower inclined beam 7-17 and arranged on left and right sides of vehicle frame 7 respectively by the short support of support 7-16 and spring 7-13 before the spring.

Actuating element comprises handlebar 5, front brake, rear brake, front fork 4 and front-wheel 1; Front fork 4 is contained in the vehicle frame 7 anterior front fork cover 7-1, front-wheel 1 is equipped with in front fork 4 bottoms, front fender apron 3 is housed on the front-wheel 1, handlebar 5 is contained in the vehicle frame 7 front upper part front forks cover 7-1, front fork 4 is connected with handlebar 5 by hanging bolt, handlebar 5 rotates by front fork 4, makes front-wheel rotate, and changes the travel direction of bicycle.

Front brake is contained in front fork 4 front ends, the front-wheel 1 that is used to stop, and rear brake is contained on the rear axle 13, the trailing wheel 12 that is used to stop, brake is being contained in handlebar 5 left and right sides.

Drive part comprises that left fork 19, right fork 25, left foot pedal 20, right pedal 24, left side rope chain 22, right rope chain 8, left flywheel 18, right flywheel 17, sprocket wheel, chain and flywheel 14.Fork axle 6 is contained in the fork axle sleeve 7-2, left side fork 15 is contained in fork axle 6 left sides, right fork 25 is contained in fork axle 6 right sides, left side fork 15 and right fork 25 bottoms are equipped with respectively that left foot pedals 20, right pedal 24, left foot is pedaled and is connected with left side rope chain 22, right rope chain 8 on axle, the right pedal axle respectively, left side rope chain 22, right rope chain 8 are connected with left spring 21, right spring 23 by left flywheel 18, right flywheel 17 respectively, left spring 21, right spring 23 are contained in respectively in left spring cover 7-14, the right spring housing 7-15, can realize adjusting the spring tightness by nut.Axis 11 is contained in the bottom bracket axle 7-10, left flywheel 7-18 is equipped with in axis 11 left sides, right flywheel 7-17 is equipped with on axis 11 right sides, and left flywheel 7-18, right flywheel 7-17 realize coplane respectively with left side rope chain 22, right rope chain 8 and left spring 21, right spring 23, promptly in same plane.

Rear axle 13 is contained on the back yoke 7-8 that rear axle support 7-9 rear end is provided with, trailing wheel 12 is contained on the rear axle 13, rear mudguard 15 is equipped with on trailing wheel 12 tops, the back brake is equipped with in rear axle 13 left sides, flywheel 14 is equipped with on rear axle 13 right sides, and sprocket wheel 26 is contained on the axis 11, drives flywheel 14 by chain 27, drive trailing wheel 12 motions, drive car load and advance.

On described rear axle 13 and the back yoke 7-8 support 16 is housed, is used to support car load.

Vehicle seat partly comprises vehicle seat 9 and bumper 10, and the vehicle seat inserted link is contained in the Saddle cover 7-6, and by the bolt adjustment up and down highly, vehicle seat 9 is made up of seat cushions, backrest, vehicle seat inserted link.The vehicle seat inserted link is contained in the Saddle cover 7-6, adjusts upper and lower height by bolt.Bumper 10 is equipped with in the seat cushions bottom, and the vehicle seat inserted link is equipped with in bumper 10 lower ends.Bumper 10 is made up of by bolted connection two springs with cavity shapes plate.Described vehicle seat 9 adopts the low level vehicle seat, the band backrest.

Described left side rope chain 22 is to adopt the special-purpose hoop that connects to be connected by steel rope and roller chain with right rope chain 8, the portion of chain of left side rope chain 22 and right rope chain 8 is meshed with left and right sides flywheel respectively, the other end links with the spring that is contained in the spring housing, each one sealing messenger chain about constituting respectively.Left side flywheel 7-18, right flywheel 7-17 are contained in vehicle frame 7 both sides of axis 11 respectively, and overriding clutch is housed respectively in it, and be identical with the flywheel of ordinary bicycle, and it can only be changeed Xiang rotation by Dan.Above sprocket wheel 26, be equipped with can before and after up-down adjustment, the band backrest the low level vehicle seat.Sprocket wheel 26 drives flywheel 14 by chain 27 and realizes unidirectional rotation, and then advances by hind axle driving trailing wheel and front-wheel.

Described front-wheel 1 adopts the different wheel diameters design with trailing wheel 12, and front-wheel 1 diameter is less than trailing wheel 12 diameters.

With reference to accompanying drawing 1～3, when left foot forward the application of force pedal when stepping on left foot and pedaling 20, left foot is pedaled 20 and is driven left side rope chains 22 by left fork 19 and drive the left flywheel 18 forward application of forces, power-transfer clutch is closed and sprocket wheel drive flywheel 14 is rotated in the forward it on, and device is travelled forward; Meanwhile, 24 corresponding motions backward of right pedal; When left foot pedals 20 when moving forward at the most preceding, 20 of right pedals move to rearmost point, the conversion pin is stepped on direction, be that right crus of diaphragm is pedaled forward and stepped on, right flywheel 17 is just changeing, and drives whole device and travels forward, and this moment, left flywheel 18 separated with sprocket wheel, left foot is pedaled 20 corresponding motions backward, finishes a working cycle until terminal point, so repeatedly travelling forward continuously of implement device.This replaces proal situation for left and right sides pin, and certainly, because the sealing of first order rope chain-driving left and right sides spring, so left and right sides pin is moved simultaneously backward or left and right sides pin independently moving separately forward, this just provides convenience for different crowd comprises disabled person's use.

Claims

1. A swing spring bicycle with unequal wheel diameters is characterized in that it is made up of a vehicle frame part, a vehicle seat part, an operating part and a driving part;

The frame part includes the front support of the swing shaft, the back support of the swing shaft, the upper inclined beam, the lower inclined beam, the front fork cover, the left spring cover, the right spring cover, the rear axle frame, the central axle sleeve and the seat cover; the upper inclined beam and the The front end of the lower inclined beam is equipped with a front fork cover, the upper part of the upper inclined beam is fixedly connected with the front support of the swing shaft and the rear support of the swing shaft, the upper ends of the front support of the swing shaft and the rear support of the swing shaft are fixedly connected with the handlebar cover, and the middle part of the frame is equipped with Center shaft sleeve, the upper part of the center shaft sleeve is equipped with a seat cover, the front end of the center support is fixedly connected with the upper inclined beam and the lower inclined beam, the rear end of the center support is connected with the flat stay and the central shaft diagonal brace, and the center shaft at the upper end of the middle support is inclined The brace is fixedly connected with the seat cover; the seat cover is connected with the rear axle frame through the rear diagonal brace, the front end of the rear axle frame is connected with the middle axle sleeve, and the rear axle fork is arranged at the rear end of the rear axle frame; the left spring cover and the right spring cover They are respectively fixed on the left and right sides of the lower slope beam of the frame through the front spring brace and the short spring brace;

The seat part includes the seat and the shock absorber. The seat is connected to the frame through the seat insert rod at the lower end, and the height of the seat is adjusted by adjusting the bolt. The seat is composed of a seat cushion, a backrest, and a seat insert rod. The lower part of the seat cushion is equipped with a shock absorber, and the lower end of the shock absorber is equipped with a seat insert rod;

The control part includes handlebars, front brakes, rear brakes, front forks and front wheels; Installed in the front fork sleeve on the upper front of the frame, the front fork is connected to the handlebar through the front fork nut, and the handlebar rotates through the front fork to make the front wheel rotate and change the driving direction of the bicycle;

Drive section includes left swing link, right swing link, left pedal, right pedal, left rope chain, right rope chain, left freewheel, right freewheel, left spring, right spring, sprocket, chain and freewheel; swing rod shaft mounted In the swing rod bushing, the left swing rod is mounted on the left side of the swing rod shaft, the right swing rod is mounted on the right side of the swing rod shaft, and the lower parts of the left swing rod and the right swing rod are respectively equipped with a left pedal, a right pedal, and a left pedal. The pedal shaft and the right pedal shaft are respectively fixedly connected with a left rope chain and a right rope chain. The left rope chain and the right rope chain are respectively connected with the left spring and the right spring through the left flywheel and the right flywheel. In the left spring sleeve and the right spring sleeve, adjust the spring tightness through the adjusting nut; the central shaft is installed in the central shaft sleeve, the left flywheel is installed on the left side of the central shaft, and the right flywheel is installed on the right side of the central shaft;

The rear axle is installed on the rear axle fork provided at the rear end of the rear axle frame, the rear wheel is installed on the rear axle, the rear fender is installed on the upper part of the rear wheel, the rear brake is installed on the left side of the rear axle, and the rear axle is installed on the right side of the rear axle. Flywheel, the sprocket drives the flywheel through the chain, drives the rear wheel to move, and drives the whole vehicle to move forward.

2. The swing spring bicycle with unequal wheel diameters according to claim 1, characterized in that the front brake is mounted on the front end of the front fork for braking the front wheels, and the rear brake is mounted on the rear axle for braking the rear wheels , The brake handle is installed on the left and right sides of the handlebar.

3. The swing spring bicycle with unequal wheel diameters according to claim 1, characterized in that the left flywheel, the right flywheel and the left rope chain, the right rope chain and the left spring and the right spring respectively realize coplanarity, that is, in the same in plane.

4. The swing spring bicycle with unequal wheel diameters according to claim 1, characterized in that the rear axle and the rear axle fork are provided with brackets for supporting the whole bicycle.

5. The swing spring bicycle with unequal wheel diameters according to claim 1, characterized in that the shock absorber is composed of two plate springs with concave cavity shapes connected by bolts.

6. The swing spring bicycle with unequal wheel diameters according to claim 1, characterized in that the left rope chain and the right rope chain are connected by a steel wire rope and a roller chain with hoops, and the left rope chain and the right rope chain The chain part of the chain is meshed with the left and right flywheels, and the other end is connected with the spring installed in the spring sleeve to form a closed transmission chain on the left and right sides respectively.

7. The oscillating spring bicycle with unequal wheel diameters according to claim 1, characterized in that the left flywheel and the right flywheel are respectively installed on both sides of the vehicle frame of the central shaft, and overrunning clutches are respectively installed therein.

8. The swing spring bicycle with unequal wheel diameters according to claim 1, characterized in that the front wheel and the rear wheel are designed with unequal wheel diameters, and the diameter of the front wheel is smaller than that of the rear wheel.

9. The swing spring bicycle with unequal wheel diameters according to claim 1, characterized in that the seat is a low seat with a backrest.