Background Art Conventional scooters, which are simply composed of a frame, a front wheel, and a rear wheel, are propelled by one foot thrusting it against the ground while the other foot is positioned on a pedal. The conventional scooters are suitable primarily for and popular with children. However, the conventional scooters have several problems. For example, because the conventional scooter is pushed forward by using only one foot thrusting it against the ground, it can cause detrimental effects on children in growth stages and children cannot enjoy it for a long time due to a feeling of fatigue in one leg.

Recently, adults and juveniles as well as children are enjoying inline skating, bicycling or scootering at their leisure and, according to this trend, scooters has been developed so that they are foldable to be simply stored in a small space of, for instance, a car trunk and drivable by chains or gears. However, the conventional foldaway scooters having a screw-type or a key-type unit are gross in appearance and complicated mechanically. Moreover, users are prone to hurt in their fingers while folding the scooter due to its crude folding unit. The

conventional drivable scooters having chains or gears are inconvenient in use and, therefore, need some improvements.

The Korean Patent Publication No. 2001-0088585 discloses a method for increasing rotation speed by mounting a gearbox in the inner part of a wheel to quickly rotate a manual wheel with one pedal and without using a chain or a belt.

Fig. 1 shows the gearbox in the above-mentioned publication patent. As shown in Fig. 1, an inner gear (8) is fixed to the gearbox in the wheel and another gear (6) is fixed to a fixing shaft (3). A pedal device (1) is stepped on to rotate the gear (6).

The gear (6) transfers the force to a gear (5) and the gear (5) then transfers the force to an adjacent gear (7). The pedal device (1) returns to its original position by a spring. Accordingly, the wheel rotates by the continuous application of pressure on the pedal device (1). However, to propel forward the scooter, a user has to step on the pedal device (1) with one foot repeatedly while standing on a board with the other foot and, therefore, the scooter may be unstable due to imbalance of force and cannot achieve high speed compared to a pedaling device using two feet.

Disclosure of Invention Accordingly, the present invention is directed to a drivable scooter with footstools that substantially obviates one or more problems due to limitations and disadvantage of the related art.

A drivable scooter with footstools according to the present invention uses planetary gear trains to reduce the size of drive unit thereof compared to other gear trains having the same velocity ratio. Additionally, the scooter can reduce the total load by dispersing the transmitted load using a plurality of planetary gears.

The planetary gear trains is small in volume compared to other gear trains having the same velocity ratio and has a good force transmission efficiency due to concentric input and output. The present invention arranges the planetary gears symmetrically to radially offset the load in each planetary gear so that only axial load can be considered in bearing and frame designs. The drive unit including gears is made of mono cast nylon to facilitate processing and reduce noise and weight. In addition, footstools and the frame are made of duralumin to improve structural strength while reducing weight.

The present invention improves stability by adopting a clamped beam type instead of a cantilever type through an ergonomic design and uses a simple one- touch button in a folding unit to ensure convenient folding and prevent users from being hurt while the scooter being folded. In addition, the drivable scooter according to the present invention includes a brake light for safe driving at night and a shock absorber to mitigate direct impacts on handlebars and human body due to vibration and shaking during driving. The shock absorber may be a spring inserted into a steering axis.

In an embodiment of the present invention, a drivable scooter with footstools comprises: drive units (50,51) consisting of two stages each of which includes four planetary gears (57) respectively; a frame (10) whose front end is connected to a folding unit (20) and whose rear end is connected to the drive units (50,51), the drive units (50,51) being positioned on both sides of the frame (10); a steering axis (11) connected to the folding unit (20), the steering axis (11) containing a shock absorber (15) with a spring inside;

a pair of front wheels (40) attached to the lower end of the steering axis (11); at least a rear wheel (41) concentrically connected with the drive units (50, 51) ; hinge members (12) formed on a predetermined part of the frame (10); footstools (30,31) whose front ends are connected to the hinge members (12) and whose rear ends are connected to a shaft by means of first links (32,33) and second links (34,35), the footstools moving up-and-down using the hinge members (12) as fixed points; and a cover having a brake light (61) thereon, the brake light being connected to a brake unit including a B-contact switch (72).

In another embodiment, a drivable scooter with footstools comprises: two frames (101, 101') being separated from each other ; at least a front wheel (103) attached to a steering axis (102) in front of the frames (101, 101') ; at least a rear wheel attached to a shaft (104) in the rear of the frames (101, 101') ; two footstools (106,106') formed on the left and right sides of the frames (101, 101'), respectively, the front end of each of the footstools (106,106') being resiliently connected to a hinge member (107,107') protruded from each frame by means of a spring (108, 108'), the rear end of each of the footstools (106,106') being connected to the shaft (104) by means of a first link (109) and a second link (110) ; a unidirectional bearing (111) connecting the shaft (104) with the second link (110) ; and

a transmitting gear (112), a plurality of accelerating gears (113,113'), and a driving gear (114) disposed between the two frames (101, 101'), the transmitting gear being operable to transmit the rotation of the shaft to the plurality of accelerating gears, the plurality of accelerating gears being operable to accelerate the rotation speed and transmit the increased rotation speed to the driving gear, the driving gear being operable to cause the rear wheel to be rotated.

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment (s) of the invention and together with the description serve to explain the principle of the invention.

Brief Description of the Drawings Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which : Fig. 1 is a cross-sectional view of a gearbox in a wheel according to a prior art ; Fig. 2 is a perspective view of a drivable scooter with footstools according to the present invention; Fig. 3 is a bottom side view of a drivable scooter with footstools according to the present invention; Fig. 4 is a side view of a drive unit of a drivable scooter with footstools according to the present invention; Fig. 5a is an enlarged view of a folding unit of a drivable scooter with

footstools according to the present invention; Fig. 5b illustrates a part in a frame side composing the folding unit in Fig.

5a ; Fig. 5c illustrates a part in a shock absorber side composing the folding unit in Fig. 5a ; Fig. 6 shows an example of a process of folding a drivable scooter with footstools according to the present invention; Fig. 7 is a perspective view of a footstool of a drivable scooter according to the present invention; Fig. 8 is a schematic diagram of a brake unit of a drivable scooter with footstools according to the present invention ; Fig. 9 is a plane view including a fragmentary cross-sectional view of a drivable scooter with footstools according to another embodiment of the present invention; Fig. 10 is an enlarged cross-sectional view of a drive unit of the drivable scooter with footstools in Fig. 9; Fig. 11 is a perspective view of a footstool of a drivable scooter according to another embodiment of the present invention; Fig. 12 is a side view illustrating movement of footstools according to an embodiment of the present invention; Fig. 13 is a side view illustrating a drive unit of a drivable scooter according to another embodiment of the present invention; Fig. 14 is a plane view including a fragmentary cross-sectional view of a drivable scooter with footstools according to another embodiment of the present invention; and

Fig. 15 is an enlarged cross-sectional view of a drive unit of the drivable scooter in Fig. 14.

<Reference> 1: pedal device 2,108, 108' : spring 3: fixing shaft 4: wheel 5,6, 7: gear 8: inner gear 10,101, 101' : frame 11,102 : steering axis 12,107, 107' : hinge member 13: handlebar 14: brake cable 15: shock absorber 20: folding unit 21,22 : folding button 23, 26, 28, 29: connecting part 24,25 : fixing hole 27 : center hole 30,31, 106, 106' : footstool 32,33, 109: first link 34,35, 110: second link 36: top of the footstool 40, 103: front wheel 41, 105,123, 123': rear wheel 50, 51 : drive unit 52: outer carrier 53: sun gear 54: inner carrier 55: ring gear connector 56: ring gear 57: planetary gear 60: cover 61 : brake light 62: dry battery 70: brake 71 : limit switch 72: B-contact switch 73: spring 104,121 : shaft 111 : unidirectional bearing 112: transmitting gear 113, 113' : accelerating gear 114,122 : driving gear

120: second frame 124, 124' : bearing 130: rectangular hole 131 : stopper Best mode for Carrying Out the Invention Reference will be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawing.

Referring to Figs. 2 and 3, a scooter of the present invention comprises a frame (10), a steering axis (11), a folding unit (20), a pair of front wheels (40), a handlebar (13), footstools (30, 31), drive units (50, 51) and at least a rear wheel (41). The folding unit (20) is inserted into the one end of the frame (10) and is connected with the steering axis (11) by means of a T-shaped shock absorber (15).

The pair of front wheels (40) are connected to the lower end of the steering axis (11) and the handlebar (13) is connected to the upper end of the steering axis (11).

The handlebar (13) is separable from the steering axis (11). The front ends of the footstools (30, 31) are fixed to hinge members (12) which are positioned on right and left sides of the frame (10) respectively and include torsion springs inside.

The footstools (30, 31) can return to their original positions by the torsion springs when pressing force is removed. The rear ends of the footstools (30,31) are connected to a shaft by means of first links (32,33) and second links (34,35).

The rear wheel (41) is connected with the drive units (50, 51) and is positioned on the rear end of the frame (10). The shock absorber (15), which mitigates impacts on the scooter while a user is driving the scooter, is positioned between the steering axis (11) and the folding unit (20). The scooter according to the present invention has good durability and makes a neat appearance since the spring for the shock absorber (15) is inserted into the steering axis (11) compared to

conventional scooters with springs installed outside of a front wheel.

As another embodiment, referring to Figs. 9 through 13, a drivable scooter with footstools may comprise two frames (101, 101'), a front wheel (103), and at least a rear wheel (105). A steering axis (102) is formed in front of the two frames (101, 101'). The front wheel (103) is attached to the steering axis (102) in front of the frames (101,101') and the rear wheel (105) is pivotally attached to a shaft (104) in the rear of the frames (101,101'). Two footstools (106,106') are formed at the left and right sides of the frames (101, 101') respectively. Each front end of the footstools (106,106') is resiliently connected to a hinge member (107,107') protruded from each of the frames (101,101') by means of a spring (108, 108').

Each rear end of the footstools (106,106') is connected to the shaft (104) by means of a first link (109) and a second link (110). The shaft (104) is coupled to the second link (110) by means of a unidirectional bearing (111), thereby rotating in one direction. A drive unit is positioned between the two frames (101, 101').

As an alternative embodiment, a scooter may comprise a pair of rear wheels. Referring to Figs. 14 and 15, a second frame (120) is fixed to the rear ends of the frames (101, 101') and a second shaft (121) is installed on the separate frame (120) by means of multiple bearings (124,124'). Two rear wheels (123, 123') are installed on both ends of the second shaft (121).

Driving methods of a scooter with footstools are described.

Referring to Figs. 10 and 12, when a user steps on the footstools (106, 106') in turn using his own feet, only the rear ends of the footstools (106, 106') move up and down because the front ends of the footstools (106,106') are hinged to the hinge members (107,107') and the rear ends are movably connected to the shaft (104) by means of links.

The downward movement of the footstools (106,106') applies pressure on the first link (109). The second link (110), which is influenced by the downward movement of the first link (109), rotates the shaft (104). Therefore, the downward movement of the footstools (106,106') is converted into rotational motion of the shaft (104) through the first link (109) and the second link (110). If a user stops pressing the footstools (106,106'), the springs (108, 108') compressed in the hinge member (107,107') are restored to upheave the footstools to the original position.

During the process that the downward movement of the footstools (106, 106') is transmitted to the shaft (104), the shaft (104), being coupled to the second link (110) by means of the unidirectional bearing (111), rotates simultaneously with the unidirectional bearing (111) only when the second link (110) rotates in a counterclockwise direction by the downward movement of the footstools. If the footstools (106,106') move upward and the second link (110) rotates in a clockwise direction, the shaft (104) is not influenced by the rotation of the second link (110). Therefore, it is possible to keep the shaft (104) from backlashing. The shaft (104), which rotates in one direction due to the unidirectional bearing (111), transmits the rotation force due to the user's weight to the rear wheel (105).

Accordingly, the mere up-and-down movement of the footstools (106, 106') causes the rotation of the rear wheel (105) so that a scooter goes forward. As a result, it is possible for a user to move both feet evenly.

A force transmission process in a drive unit according to the movement of the footstools (106,106') is described.

Fig. 4 shows planetary gear trains of a drive unit according to an embodiment of the present invention. As shown in Fig. 4, the planetary gear trains

comprise a sun gear (53), outer carrier (52), inner carrier (54), ring gear (56), and multiple planetary gears (57). The sun gear (53), outer carrier (52), and inner carrier (54) rotate separately. The ring gear (56) is fixed to the frame and the outer carrier (52) is fixed to the shaft. The multiple planetary gears (57) rotate and revolve at the same time. The outer carrier (52), inner carrier (54), and multiple planetary gears (57) are used for input and the sun gear (53) is used for output.

When a user steps on one of the footstools, the force is transmitted to the shaft via the first link (32,33) and the second link (34,35). When the shaft rotates the outer carrier (52), one planetary gear (57) rotates and revolves at the same time. The one planetary gear (57) rotates the inner carrier (54) through the sun gear (53). Similarly, a plurality of planetary gears (57) and the sun gear (53) rotate and, finally, the shaft connected to the sun gear (53) rotates the rear wheel. Here, the speed ratio of input to output may increase as the number of stages in planetary gear trains increases. For example, eight planetary gears may constitute two stages each of which consists of four planetary gears so that one input yields 16 outputs. The gears are preferably made of mono cast nylon to reduce noise and weight.

In another embodiment, a drivable scooter of the present invention may comprise a different drive unit as shown in Fig. 10. Referring to Fig. 10, the downward movement of the footstools (106,106') is transmitted to the unidirectional bearing (111) via the first link (109) and the second link (110), and the rotation of the unidirectional bearing (111) is transmitted to the shaft (104) only if the unidirectional bearing (111) rotates in a correct direction. A transmitting gear (112) then transmits the rotation of the shaft (104) to accelerating gears (113,113'). The accelerating gears (113,113'), which have

acceleration effect according to gear ratio, increase the rotation speed and transmit the increased rotation speed to a driving gear (114). Finally, the driving gear (114) transmits the rotation force to the rear wheel (105) and the rear wheel (105), which is connected with the driving gear (114), rotates according to up- and-down movement of the footstools (106, 106'). As a result, a scooter is propelled and moves forward.

Here, the transmitting gear (112), the accelerating gears (113,113'), and the driving gear (114) can be contacted directly one another as in Fig. 13 or be connected with one another by means of belts. The driving gear (114), a plurality of accelerating gears (113,113'), and the transmitting gear (112) are positioned between the two frames (101, 101').

Referring to Figs. 14 and 15, in case of a scooter with two rear wheels, a second frame (120) is fixed to the rear ends of the frames (101, 101') and a second shaft (121) is connected to the second frame (120) by means of multiple bearings (124, 124'). Two rear wheels (123, 123') are pivotally attached to two ends of the second shaft (121). A driving gear (122) is formed on the center of the separate shaft (121).

The downward movement of the footstools (106,106') is transmitted to the unidirectional bearing (111) via the first link (109) and the second link (110), and the rotation of the unidirectional bearing (111) is transmitted to the shaft (104).

The rotational force of the shaft (104) is transmitted to the driving gear (122) on the second shaft (121) through the transmitting gear (112) and the accelerating gears (113,113'). Then, the driving gear (122) rotates the second shaft (121) using the rotational force from the accelerating gears (113,113'). Therefore, the second shaft (121) and the rear wheels (123,123') are simultaneously rotated by means of

the driving gear (122) that rotates at a high speed and the scooter can move forward.

A folding unit of a scooter according to the present invention is described.

Referring to Fig. 5b, a member inserted into the frame comprises a cylinder- shaped first connecting part (23) that is connected to the frame and a second connecting part (26) with a center hole (27) and two fixing holes (24,25) that is connected to a member inserted into the shock absorber. Referring to Fig. 5c, the member inserted into the shock absorber comprises a cylinder-shaped first connecting part (28) that is connected to the shock absorber and a second connecting part (29) that is connected to the member inserted into the frame. The fixing holes (24, 25) and the center hole (27) are formed to make an appropriate angle for folding.

Referring Fig. Sa, when the folding buttons (21, 22) are pressed at one time, a rod (not shown) with an appropriate diameter is detached from the fixing hole (24) and is jointed to the other fixing hole (25) so that the steering axis (11) can be folded as shown in Fig. 6. Similarly, the steering axis (11) can be unfolded.

Referring to Fig. 7, the footstools (30,31) are positioned on both sides of the frame for the balance of the scooter. The footstools (30, 31) are made of duralumin thereby being light in weight and are coated to prevent sliding on the top surface (36) of the footstool. In addition, the end parts of footstools (30,31) slope upward to prevent user's shoes from sliding on the footstools.

In another embodiment, as shown in Fig. 11, the footstools may have stoppers formed around the edge thereof to prevent user's shoes from sliding out of the footstools.

In another embodiment, as shown in Fig. 14, a rectangular hole (130) is

formed on the center of each of the footstools (106,106') and a stopper (131) is inserted into the rectangular hole (130). The position of the stopper (131) can be adjusted appropriately within the rectangular hole (130) by use of conventional tightening bolt/nut mechanism and, therefore, user's shoes can be fixed safely on the top of the footstools (106,106').

Fig. 8 is a schematic diagram of a brake unit of a drivable scooter with footstools according to an embodiment of the present invention. The brake unit comprises a brake (70), a limit switch (71), a B-contact switch (72), a spring (73), a dry battery (74), and a brake light (61) positioned on a cover (60). When a user puts on the brake using a brake handle, the brake (70) operates through a brake cable (14) and the spring (73) stretches. Then, the limit switch (71) is detached from the B-contact switch (72) and the B-contact switch (72) works. Therefore, the brake light (61) is turned on by detachment between the limit switch (71) and the B-contact switch (72). On the contrary, the brake light (61) is turned off when the limit switch (71) is contact with the 13-contact switch (72). The brake light (61) is helpful when a user rides the scooter at night.

Industrial applicability Accordingly, the present invention improves stability by adopting a clamped beam type instead of a cantilever type through an ergonomic design and uses a simple one-touch button in a folding unit for convenient usage and to prevent users from being hurt while folding the scooter. In addition, this invention provides a brake light for safe driving at night and mitigates direct impacts on handlebars and human body due to vibration and shaking by inserting a spring as a shock absorber in a steering axis.

By using two feet of a user, the drivable scooter with footstools is effective for well-balanced growth of infants and children and the user may easily avoid fatigue although he/she uses it for a long time. Moreover, the scooter is effective for training lower body, increasing pliability of knees of children, enhancing cardiopulmonary functions, and keeping a good figure. In addition, the scooter does not make a loud noise and need no special maintenance.