WO2005058679A1

WO2005058679A1 - Drive mechanism, in particular for unicycles

Info

Publication number: WO2005058679A1
Application number: PCT/HU2004/000120
Authority: WO
Inventors: Hriszto Atanaszov Dacsev; Imre József BESENYÖ; Magdolna Demeter; József Gyalus; Árpád KÖSZEGI; Lajos LETÁK; Lajos Mennich; Miklós Konrád MOLNÁR; József RAKÁCS; Miklós RÓZSA; Richárd SCHEILI; Zoltán TÁTOS; Sándorné VIG
Original assignee: Hriszto Atanaszov Dacsev; Besenyoe Imre Jozsef; Magdolna Demeter; Gyalus Jozsef; Koeszegi Arpad; Letak Lajos; Lajos Mennich; Molnar Miklos Konrad; Rakacs Jozsef; Rozsa Miklos; Scheili Richard; Tatos Zoltan; Vig Sandorne
Priority date: 2003-12-19
Filing date: 2004-12-16
Publication date: 2005-06-30
Also published as: AT9213U1; UA21261U; HUP0304097A2; RU58447U8; HU3117U; CN2860987Y; RU58447U1; DE212004000076U1; HU0304097D0; HU0500241V0; JP3130942U

Abstract

The drive mechanism comprises a driven wheel (12) rotatably mounted in a sleeve fixedly secured to a cycle frame (10), and a right-side and a left-side crank (6, 8) rotatably coupled to said cycle frame (10), wherein rotational axis of the right-side and the left-side crank (6, 8) is different from rotational axis (16) of the driven wheel (12), said rotational axis of the right-side and the left-side crank (6, 8) being parallel to rotational axis (16) of the driven wheel (12) and having a distance therefrom which is equal to or smaller than the radius of the wheel (12). Rotational axis of the right-side and the left-side crank (6, 8) has a fixed position relative to rotational axis of the driven wheel (12). The drive mechanism comprises a right-side power transmission mechanism coupled to the right-side crank (6) and the wheel (12), and a left-side power transmission mechanism coupled to the left-side crank (8) and the wheel (12), wherein the right-side power transmission mechanism and the left-side power transmission mechanism are in forced drive coupling through said wheel (12).

Description

Drive mechanism, in particular for unicycles

The present invention relates to a drive mechanism, in particular for unicycles. In case of the most common type of the bicycles driven by cranks, said cranks, both of which are provided with a pedal, are rotating a sprocket by a chain, wherein the chain led around said first sprocket is rotating a second sprocket fixedly secured to the driven wheel, most commonly the rear wheel. The driven sprocket is coupled to the driven wheel through a free running mechanism, although bicycles with permanent driving are also well known in the art. In case of permanent driving, the driven sprocket is rigidly fixed to the driven wheel. The situation of unicycles is different in that the cranks are directly coupled to the single cycle wheel in general, and rotational axis of the cranks is the same as rotational axis of the driven wheel. However, there also exist unicycles known from the prior art, in which rotational axis of the cranks is different from rotational axis of the wheel. GB Patent No. 191 ,483 discloses a unicycle, especially for stage and amusement purposes, in which the cycle frame provided with a seat and mounted to the wheel is moving alternately up and down while the unicycle is running, i.e. the distance between rotational axis of the cranks and that of the driven wheel is changing periodically. US Patent No. 5,002,295 discloses a unicycle in which the frame supporting the seat is also moving alternately up and down during run. In case of this type of unicycle, however, rotational axis of the cranks is at a constant distance from rotational axis of the driven wheel, said distance being adjustable by means of a positioning mechanism. Due to the alternative up and down motion of the cycle frame, the above mentioned unicycles are advantageous for amusement purposes, but inadequate for providing the experience of traditional bicycling or unicycling. Moreover, the drive mechanism of such unicycles require utilization of parts different from those of the common drive mechanisms, which increases the costs of production and repairing. An objective of the present invention is to provide a drive mechanism, in particular for unicycles, in which rotational axis of the cranks is parallel to, and different from rotational axis of the driven wheel in one hand, and, on the other hand, the cycle frame mounted to the wheel has a constant position relative to the rotational axis of the driven wheel during run. Another objective of the present invention is to provide a drive mechanism consisting of parts commonly utilized in most bicycles, and thus reducing the costs of production and eventual repairing thereof to a more economic level. These and other objectives are achieved in the present invention by providing a drive mechanism, in particular for unicycles, comprising a driven wheel rotatably mounted in a sleeve fixedly secured to a cycle frame, and a right-side and a left-side crank rotatably coupled to said cycle frame, wherein rotational axis of the right-side and the left-side crank is different from rotational axis of the driven wheel, said rotational axis of the right-side and the left-side crank being parallel to rotational axis of the driven wheel and having a distance therefrom which is equal to or smaller than the radius of the wheel. Rotational axis of the right-side and the left-side crank has a fixed position relative to rotational axis of the driven wheel. The drive mechanism comprises a right-side power transmission mechanism coupled to the right-side crank and the wheel and a left-side power transmission mechanism coupled to the left-side crank and the wheel, wherein the right-side power transmission mechanism and the left-side power transmission mechanism are in forced drive coupling through said wheel. Both the right-side power transmission mechanism and the left-side power transmission mechanism may be in the form of a chained drive mechanism at least comprising first sprockets coupled to said cranks, respectively, second sprockets coupled to said wheel, and chains led around said first and second sprockets, respectively. The right-side power transmission mechanism and the left-side power transmission mechanism may be in the form of a geared drive mechanism at least comprising first gears coupled to said cranks, respectively; second interposed gears coupled to said first gears, respectively, and rotatably mounted to the cycle frame; and third gears coupled to said second interposed gears, respectively, and fixedly secured to said wheel. Preferably, rotational axis of the right-side crank and rotational axis of the left-side crank are incident. Rotational axis of the right-side crank and/or rotational axis of the leftside crank may have adjustable position relative to rotational axis of the driven wheel. Preferably, the right-side power transmission mechanism and/or the leftside power transmission mechanism are further supplied with a mechanical or electrical driving means. Further objectives and advantages of the present invention will be described in more detail by means of the preferred embodiments with reference to the accompanying^' drawings, wherein:

- Figure 1 is a front view of the drive mechanism in accordance with the present invention,

- Figure 2 is a side view of the drive mechanism in accordance with the present invention,

- Figure 3 is a side view of the drive mechanism, according to another embodiment of the present invention, and

- Figure 4 is a schematic view of a unicycle supplied with the drive mechanism in accordance with the present invention. Referring to the drawings and initially to Figure 1 and 2, wherein Figure 1 shows the front view of the drive mechanism, whereas Figure 2 shows a side view of the drive mechanism of the preferred embodiment of the present invention, the drive mechanism comprises cranks 6, 8 with pedal 14, and a left- side and a right-side power transmission mechanism coupled to said cranks 6, 8, respectively, and to a driven wheel 12. The cranks 6, 8 are arranged to rotate in adverse phase. The right-side power transmission mechanism comprises a sprocket 20 coupled to the crank 6 through an axle 18, another sprocket 24 coupled to the driven wheel 12, and a chain 28 led around said sprockets 20, 24. The axle 18 is rotatably mounted in a sleeve fixedly secured to the cycle frame 10. Structure of the left-side power transmission mechanism is similar to that of the right-side power transmission mechanism, i.e. the crank 8 is coupled to a sprocket 22 through an axle 18, wherein said sprocket 22 rotates another sprocket 26 via a chain 30, said sprocket 26 being fixedly secured to the driven wheel 12. The sprockets 24, 26 are in constant position relative to each other. We note that said driven wheel 12 may be equipped with a hub allowing free running thereof, instead of being permanently driven by the cranks 6, 8. The main feature of the drive mechanism introduced above is that rotational axis of the cranks 6, 8 is different from, but parallel to rotational axis 16 of the wheel 12, while the distance between said two rotational axes is constant. The distance between rotational axis 16 and rotational axis of the cranks 6, 8 is not greater, preferably smaller than radius of the wheel 12. As Figure 1 and 2 shows, rotational axis of the cranks 6, 8 is preferably located between rotational axis 16 of the wheel 12 and the ground. However, rotational axis of the cranks 6, 8 may be arranged above rotational axis 16 as well. In another preferred embodiment of the present invention (not shown in the drawings), the axles 18 of the cranks 6, 8 may have variable position. The position of each axles 18 may be adjusted together or separately. In this case, the cycle frame 10 is to be formed to allow changing position of the axles 18 and fixing the axles 18 in the recently adjusted position. In a rather simple case, position of the axles 18 may be changed by rotating them around rotational axis of the sprockets 24, 26, i.e. by rotating them around rotational axis 16 of the wheel 12. In a more complicated case, however, the distance between the axles 18 of the cranks 6, 8 and the rotational axis 16 of the wheel 12 may also be varied by interposing one or more gears into the chained drive mechanism. Figure 3 shows another preferred embodiment of the drive mechanism according to the present invention, in which the right-side and the left-side power transmission mechanisms are in the form of a geared drive, wherein power transmission between gears 20f, 22f coupled to cranks 6, 8, respectively, and gears 24f, 26f coupled to the driven wheel 12 is performed by means of interposed gears 32f, 34f, respectively, instead of a chain mentioned before. As shown in Figure 3, the interposed gears 32f, 34f are rotatably secured to the cycle frame 10. Depending on the size of the other gears, rotational axis of the interposed gears 32f, 34f may either intersect the line connecting the centres of rotation of gears 20f, 22f and 24f, 26f, or may be located to a predetermined distance form said line, as shown on Figure 3. If the geared power transmission system of Figure 3 is embedded in a house mounted to the cycle frame 10, the interposed gears 32f, 34f may be secured to said house by means of a sleeve. Similarly to the chained drive mechanism, axles 18 coupled to cranks 6, 8 may be positioned together or separately form each other. It is obvious, however, that due to the contact between the gears, said geared power transmission assembly may be moved only as a whole by rotating it around the centre of rotation of said gears 24f, 26f. Figure 4 shows a schematic view of a unicycle using the drive mechanism according to the first embodiment of the present invention. It will be understood by those skilled in the art that the present invention is not limited to applications in unicycles, but may be also adapted for bicycles, tricycles, etc. The drive mechanism according to the present invention comprises commonly used parts, e.g. gears, sprockets, cranks or pedals, which allows economic production and repairing of the vehicle.

Claims

What we claim is:

1. Drive mechanism, in particular for unicycles, comprising a driven wheel (12) rotatably mounted in a sleeve fixedly secured to a cycle frame (10), and a right- side and a left-side crank (6, 8) rotatably coupled to said cycle frame (10), wherein rotational axis of the right-side and the left-side crank (6, 8) is different from rotational axis (16) of the driven wheel (12), said rotational axis of the right- side and the left-side crank (6, 8) being parallel to rotational axis (16) of the driven wheel (12) and having a distance therefrom which is equal to or smaller than the radius of the wheel (12), characterized in that rotational axis of the right-side and the left-side crank (6, 8) has a fixed position relative to rotational axis of the driven wheel (12); the drive mechanism comprises a right-side power transmission mechanism coupled to the right-side crank (6) and the wheel (12), and a left-side power transmission mechanism coupled to the left-side crank (8) and the wheel (12), wherein the right-side power transmission mechanism and the left-side power transmission mechanism are in forced drive coupling through said wheel (12).

2. The drive mechanism of claim 1 , characterized in that both the right-side power transmission mechanism and the left-side power transmission mechanism are in the form of a chained drive mechanism at least comprising first sprockets (20, 22) coupled to said cranks (6, 8), respectively, second sprockets (24, 26) coupled to said wheel (12), and chains (28, 30) led around said first and second sprockets (20, 22, 24, 26), respectively.

3. The drive mechanism of claim 1 , characterized in that the right-side power transmission mechanism and the left-side power transmission mechanism are in the form of a geared drive mechanism at least comprising first gears (20f, 22f) coupled to said cranks (6, 8), respectively; second interposed gears (32f, 34f) coupled to said first gears (20f, 22f), respectively, and rotatably mounted to the cycle frame (10); and third gears (24f, 26f) coupled to said second interposed gears (32f, 34f), respectively, and fixedly secured to said wheel (12).

4. The drive mechanism of any one of claims 1 to 3, characterized in that rotational axis of the right-side crank (6) and rotational axis of the left-side crank (8) are incident.

5. The drive mechanism of any one of claims 1 to 3, characterized in that rotational axis of the right-side crank (6) and/or rotational axis of the left-side crank (8) have adjustable position relative to rotational axis (16) of the driven wheel (12).

6. The drive mechanism of any one of claims 1 to 5, characterized in that the right-side power transmission mechanism and/or the left-side power transmission mechanism are further supplied with a mechanical or electrical driving means.