International patent application publication No. WO2015/092532 discloses a velocipede with front-wheel drive comprising at least one front wheel, with the pedal axle coinciding with the front axis of the hub of said front wheel, a frame, a fork, at least two seats, a transmission mechanism of the movement, a handlebar and a rear wheel.

United Kingdom patent application publication No. 190000806 discloses an auxiliary hand actuated driving mechanism for the front wheel of cycles. Similar design is disclosed in US patent publication No. 4,773,662.

Typical tandem bicycle is disclosed in US patent publication No. 4,502,705 having two seats and two sets of pedals for driving rear wheel.

Summary of the Invention

The aim of the invention is to design a tandem bicycle. The tandem bicycle is designed so that a rider of the bicycle is sitting in the regular or main seat and other or second rider of the bicycle is sitting in a seat that is connected to the movable part of the bicycle - the front fork and/or the handlebars. The second rider drives a front wheel of the bicycle with his or her muscle force without regard to the type of the drive. The drive may be selected for the known drive types such as chain drive, belt drive, gear wheel drive, direct pedal drive to a front wheel shaft, or any other drive type known to the skilled person.

A tandem bicycle comprises a frame, a front and a rear wheel, a rear wheel drive, a main seat for a rider and a front fork. The tandem bicycle further comprises a front seat attached to the front fork or handlebars so that the front seat is movable together with the front fork and/or handlebars. The handlebars may be considered as a part of the front fork. The tandem bicycle further comprises a front wheel drive for drive of the front wheel by a rider in the front seat. The front seat itself comprises a frame that is attached to the front fork and/or to the handlebars. The front wheel drive may be attached to the front seat or to the frame of the front seat as well as the front wheel drive may be designed as a direct pedal drive installed on the hub of the front wheel.

The front seat may further comprise a front luggage carrier. In one embodiment the tandem bicycle comprises the front frame attached to the front fork so that it may move or rotate together with the front fork. The front seat is attached to the front frame so that it is in front of the front fork. The bicycle further comprises the front wheel drive, wherein the main sprocket or drive sprocket with pedals is attached to the front frame is a position where a driver in the front seat can pedal the main sprocket. A driven sprocket of the front wheel drive is attached to a hub of the front wheel. Both sprockets are connected by roller chain so that rotation of the main sprocket is transferred to the driven sprocket that drives the front wheel.

The front frame or the front seat is equipped with front wheel drive adjusting mechanism to be able to adjust the position of pedals of the front wheel drive according to the dimensions or growth of a rider in the front seat.

The tandem bicycle further comprises a seat adjustment mechanism to adjust the front seat relative the pedals of the front wheel drive in order to adapt to a size of a rider in the front seat.

Application of the tandem bicycle mainly refers to transporting of children of age from 2 to 10 years by providing a constant visual contact with the adult, and the child's participation in ensuring of the ride movement thus creating a safe, healthy and useful physical activity.

Application of the invention may be demonstrated in manufacturing of bicycle luggage carriers of a special structure which comprises combination of the luggage carrier, the seat, the pedals, the hub and the gear wheels for simple equipping of any bicycle herewith, or manufacturing of the referred to elements in one assembly with a specially adapted front fork and handle-bars of the bicycle. While the inventions have been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the scope of the invention. Therefore, it is intended that the inventions not be limited to the particular embodiments disclosed herein.

Brief description of the Drawings

Fig. 1 illustrates a tandem bicycle with both wheels 2, 3 drive where a front wheel drive 22 is attached to a front frame 20.

Fig. 2 illustrates a tandem bicycle with both wheels 2, 3 drive where a front wheel drive 22 is attached to a front seat 21.

Fig. 3 illustrates one embodiments of a tandem bicycle.

Fig. 4 illustrates a close-up view a front wheel drive 22 of the tandem bicycle as shown in Fig. 3.

Fig. 5 illustrates a close-up view a front wheel drive 22 of the tandem bicycle as shown in Fig. 3.

Figs. 1 and 2 shows a tandem bicycle comprising a frame 1, and a front wheel 3 with a hub 12, a rear wheel 2 and a rear wheel drive 4 comprising pedals 8, a drive sprocket 9, a driven sprocket 10 and a chain 11. The tandem bicycle further comprises a main seat 5, a front fork 6 and handlebars 7. The aforementioned features are known from the prior art for simple or normal bicycle. The object of invention is characterized in that it further comprises a front frame 20 with a front seat 21, wherein the front frame is attached to the movable part of the bicycle, which is the front fork 6. Fig. 1 shows that the front frame 20 further comprises a front wheel drive 22. Fig. 2 shows another embodiment where the front wheel drive is attached to the front seat 21. The front wheel drive 22 further comprises a drive sprocket 24, a driven sprocket 25, a chain 26 and pedals 23. The driven sprocket 25 is connected to the hub 12 of the front wheel 3. The drive sprocket 24 may be rotatably attached to the front frame 20 as shown in Fig. 1 and in Figs. 3 to 5, or may be rotatably attached to the front seat 21 as shown in Fig. 2. The front wheel drive 22 is driven by the second rider who sits in the front seat 21.

Figs. 3 to 5 illustrates a practical implementation of schematics shown in Fig. 1. The tandem bicycle comprising a front frame 20 with a front seat 21, wherein the front frame 20 is attached to the movable part of the bicycle, which is the front fork 6. The front frame 20 further comprises a front wheel drive 22. The front wheel drive is rotatably attached to the front frame 20. The front wheel drive 22 further comprises a drive sprocket 24, a driven sprocket 25, a chain 26 and pedals 23. The driven sprocket 25 is connected to the hub 12 of the front wheel 3. Accordingly, the front wheel drive 22 is driven by the second rider who sits in the front seat 21. The tandem bicycle further comprises a seat adjustment mechanism 27 as a row of holes in a front frame 20 to adjust the front seat 21 relative the pedals 23 of the front wheel drive 22 in order to adapt to a size of a rider in the front seat 21. List of references in the drawings

1 - a frame;

2 - a rear wheel;

3 - a front wheel;

4 - a rear wheel drive;

5 - a main seat;

6 - a front fork;

7 - handlebars;

8 - pedals of the rear wheel drive;

9 - a drive sprocket of the rear wheel drive;

10 - a driven sprocket of the rear wheel drive;

11 - a chain of the rear wheel drive;

12 - a hub of the front wheel

20 - a front frame;

21 - a front seat;

22 - a front wheel drive;

23 - pedals of the front wheel drive;

24 - a drive sprocket of the front wheel drive;

25 - a driven sprocket of the front wheel drive;

26 - a chain of the front wheel drive; and

27 - a set adjustment mechanism.