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TEXT OF THE DESCRIPTION

Field of the invention

The present invention relates to a folding bicycle. The invention is aimed in particular at a folding bicycle of the type with pedal assistance obtained with an electric motor, even though application to conventional bicycles is not excluded.

Prior art

There have been known and used for some time now folding bicycles of the type comprising:

- a frame, including a main diagonal element having a front end that carries a head tube and a rear end that carries a crank-axle unit of the bicycle,

- a rear wheel rotatably mounted on a rear-wheel support connected to said frame, said rear wheel having a hub that carries a sprocket wheel connected by means of a chain drive or a belt drive to a chainwheel of said crank-axle unit, and

- a front wheel rotatably mounted on a front-wheel support connected to a steering tube that is rotatably mounted within said head tube,

- wherein said frame has at least one first, substantially vertical, folding axis that enables the rear wheel to be moved, together with the rear-wheel support and the crank-axle unit, via a rotation of approximately 180°, from a position of normal use to a folded position in which the rear wheel is substantially arranged alongside the front wheel.

Bicycles of the type referred to above that have so far been built are not, however, completely satisfactory from various points of view, in particular as regards simplicity of the structure, efficiency of the folding system, and overall dimensions of the bicycle in the folded condition. Known systems moreover frequently jeopardize the possibility of producing bicycles that in the condition of normal use have a styling, a weight, and levels of performance similar to those of a normal high-range bicycle, especially with reference to the drivetrain and to the size of the wheels.

Object of the invention

Consequently, an object of the invention is to provide a folding bicycle of the type referred to above that will be simple and functional, will present a low weight, will have minimum overall dimensions in the folded condition, will afford simple folding operations via quick and safe lockingunlocking systems, and at the same time in its condition of normal use will be similar, both at the level of quality of design and as regards performance, to a high-range bicycle of the non-folding type.

A further object is to provide a bicycle of the type referred to above that will be suited to being implemented in particular in the form of bicycle with pedal assistance, provided with a pedal-assist electric motor.

Summary of the invention

With a view to achieving the aforesaid objects, the subject of the present invention is a folding bicycle having the characteristics referred to at the start of the present description and moreover characterized in that the front-wheel support includes a second folding axis oriented in a direction transverse to the general plane of the bicycle that enables the front wheel to be moved from a position of normal use to a folded position in which the axis of the front wheel is closer to, or substantially coincident with, the axis of the rear wheel when the latter is in its folded position.

The second folding axis is defined by an articulated connection between a lower portion of said front-wheel support and an upper portion of said front-wheel support. The first folding axis of the frame is defined by an articulated connection between the rear end of said main diagonal element of the frame and a structure that includes said crank-axle unit and said rear-wheel support.

In the case where the bicycle is a bicycle with pedal assistance, said crank-axle unit includes an electric motor operatively connected to said chainwheel comprised in the crank-axle unit of the bicycle.

In the preferred embodiment, said rear-wheel support and said front-wheel support extend only on one and the same side of the bicycle in such a way that, in the folded condition about the first folding axis, said supports are on the outside of the ensemble of the two wheels arranged alongside one another.

Preferably, said frame includes a third folding axis oriented in a direction transverse to the general plane of the bicycle and defined by an articulated connection between the rear end of the main diagonal element of the frame and a seat tube of the bicycle, which carries a bicycle saddle, in such a way that the seat tube with the saddle carried thereby can be folded into a position in which it is adjacent to the main diagonal element of the frame.

According to a further preferred characteristic, the steering tube includes a fourth folding axis oriented in a direction transverse to the general plane of the bicycle and defined by an articulated connection between an upper portion of said steering tube and a lower portion of said steering tube that carries a bicycle handlebar in such a way that said upper portion of the steering tube, with the handlebar carried thereby, can be folded adjacent to said main diagonal element of the frame. Furthermore, said handlebar comprises two handlebar half-portions connected to said upper portion of the steering tube in a foldable manner.

The crank-axle unit includes a crank axle that carries two crank arms, each provided with a pedal articulated to the respective crank arm so that it can be folded, through a rotation of 180°, onto the inner side of the crank arm.

According to a further important characteristic of the present invention, each of the aforesaid folding axes is defined by an articulated connection between a first part and a second part and by the fact that associated to each articulated connection is a device for quick locking and unlocking of the articulated connection into/from a configuration of normal use, said locking and unlocking device comprising a cam member, which is rotatably mounted on one of the two parts of the articulated connection and can be displaced by means of an actuation lever, against the action of spring means, between a released, unlocking, position and a locking position, in which said cam member engages against a striker element carried by the other part of the articulated connection.

Thanks to the aforesaid characteristics, the bicycle according to the invention achieves the purposes that have been referred to above by means of a structure that is extremely simple and functional.

Detailed description of a preferred embodiment

Further characteristics and advantages of the invention will emerge from the ensuing description with reference to the annexed drawings, which are provided purely by way of non-limiting example and in which:

- Figures 1 and 2 are two perspective views of a preferred embodiment of the folding bicycle according to the present invention;

- Figures 3-6 illustrate the bicycle of the previous figures with the frame in different folded positions;

- Figure 7 is a perspective view of the bicycle in its completely folded configuration;

- Figure 8 is a cross-sectional view of a rear portion of the bicycle of the previous figures;

- Figure 9 illustrates the details of Figure 8 at an enlarged scale;

- Figures 10 and 11 are, respectively, an exploded perspective view and a side view of the components shown in Figures 8 and 9;

- Figure 12 is a perspective view of the bicycle of the previous figures, represented in which are the folding axes of the frame; and

- Figure 13 is a sectioned view of an example of articulated connection integrated in the frame of the bicycle represented in the previous figures.

In the annexed drawings, designated by the reference B is a preferred embodiment of a folding bicycle according to the present invention. The bicycle B has a frame T rotatably mounted on which are a front wheel 6 and a rear wheel 4. The rear wheel 4 is rotatably mounted on a rear-wheel support 5, which is connected to the frame T, and the front wheel 6 is rotatably mounted on a front-wheel support 7. The frame T comprises a main diagonal frame element 1 , which has a front end 11 that carries a head tube 2 and a rear end 12 that carries a crank-axle unit G of the bicycle B.

According to a technique in itself known, the rear wheel 4 has a hub 23 that carries a sprocket wheel 13 connected by means of a chain drive 9 to a chainwheel 10 of the crank-axle unit G, whereas the front wheel 6 has its support 7 connected to a steering tube 8, which is rotatably mounted within the head tube 2. As an alternative to the embodiment illustrated in the annexed drawings, the chain drive 9 of the bicycle B can also be obtained by belt means instead of the chain.

In the preferred embodiment of the invention illustrated in the drawings, the folding bicycle B is a bicycle with pedal assistance, with its crank-axle unit G comprising an electric motor, which is operatively connected to the chainwheel 10 comprised in the crank-axle unit G. In the present description and in the annexed drawings, the constructional details regarding the electric motor are not presented since these details can be obtained in any known way and also in so far as elimination of these details from the drawings renders the latter more readily and easily understandable. On the other hand, the invention can be equally applied to a conventional bicycle without any electromechanical aid for the user of the bicycle.

Further structural characteristics of the bicycle B regarding the rear wheel 4 and how it is engaged on the support 5 are illustrated in Figures 8-10. The rear wheel 4 is mounted at a rear portion of the support 5 having a perforated seat 29 mounted within which is a chain of elements. These elements, illustrated in particular in the exploded view of Figure 10, in the mounted condition are coaxial and engaged on a pin 26 provided within the seat 29. The hub 23 that carries the sprocket wheel 13 is screwed to a brake disk 24 and to a flange 25. In addition, once again with reference to Figure 10, mounted within the perforated seat 29 of the support 5 is a cylindrical member 30, which carries a pair of bearings 27, 28, which are provided with a spacer 31. Finally, at the opposite end of the sprocket wheel 13, the chain of elements described above terminates with a flange 32. In the mounted condition, the chain of elements described above is blocked at the rear portion of the support 5, by tightening of two screws 33. Furthermore, in particular with reference to the side view of Figure 11 , engaged in the cylindrical member 30 is a lever 34, which is pre-arranged for adjusting the pull of the drive 9 by means of manual regulation performed by a user.

According to a fundamental characteristic of the invention, the folding bicycle B has a plurality of folding axes I, II, III, IV (Figure 12), which make it possible to displace portions of the bicycle B from a position of normal use to a folded position (Figure 7).

With reference in particular to Figures 3, 4, the frame T has a first, substantially vertical, folding axis I that enables the rear wheel 4 to be moved, together with its support 5 and the crank-axle unit G, via a rotation through 180°, from the position of normal use to a folded position in which the rear wheel 4 is substantially arranged alongside the front wheel 6. The first folding axis I of the frame T is defined by an articulated connection between the rear end 12 of said main diagonal element 1 of the frame T and a structure 3 that includes inside it the electric motor (Figures 3, 4).

According to an important structural characteristic of the bicycle B, the rear-wheel support 5 and the front-wheel support 7 extend only on one and the same side of the bicycle B, in such a way that, in the folded condition about the first folding axis I, the supports 5, 7 are on the outside of the ensemble of the two wheels arranged alongside one another (Figures 4 and 5). This structural solution is particularly indicated to facilitate folding of the bicycle without jeopardizing the aesthetic appearance of the bicycle itself.

According to an essential characteristic of the invention, the frontwheel support 7 includes a second folding axis II. In particular, the second folding axis II is defined by an articulated connection between a lower portion 81 of the steering tube 8 and an upper portion of the front-wheel support 7 (Figures 5 and 6). The second axis II is oriented in a direction transverse to the general plane of the bicycle B and enables the front wheel 6 to be moved from a position of normal use to a folded position. As shown in Figures 5-7, in this folded position, the axis of the front wheel 6 is closer to, or substantially coincident with, the axis of the rear wheel 4 when the latter is in its folded position.

Thanks to the possibility of folding the frame T of the bicycle B both according to a movement about the first axis I and according to a movement about the second axis II, the overall dimensions of the bicycle in its folded configuration is very contained.

In order to reduce further the overall dimensions of the bicycle B in the folded configuration, the bicycle B has a third folding axis III (illustrated in Figures 5 and 12) oriented in a direction transverse to the general plane of the bicycle B. This third folding axis III is defined by an articulated connection between the rear end 12 of the main diagonal element 1 of the frame T and a seat tube 14 of the bicycle B, which carries a bicycle saddle 15, in such a way that the seat tube 14 with the saddle 15 carried thereby can be folded into a position in which it is adjacent to the main diagonal element 1 of the frame.

Moreover, according to a further preferred characteristic of the invention illustrated in Figures 5 and 12, the steering tube 8 includes a fourth folding axis IV oriented in a direction transverse to the general plane of the bicycle B, which is defined by an articulated connection between an intermediate portion 82 of the steering tube 8 and an upper portion 83 of the steering tube 8, which carries a bicycle handlebar 16. Consequently, the upper portion 83 of the steering tube 8, with the handlebar 16 carried thereby, can be folded adjacent to the main diagonal element 1 of the frame.

According to further preferred characteristics of the invention, once again in order to reduce the overall dimensions of the bicycle when it is folded, the handlebar 16 comprises two handlebar half-portions 160 connected to the upper portion 83 of the steering tube 8 in a foldable manner (Figure 7), and moreover the crank-axle unit G includes a crank axle, which carries two crank arms, each provided with a pedal 18 articulated to the respective crank arm so that it can be folded, through a rotation of 180°, onto the inner side of the crank arm.

Thanks to the possibility of folding the frame T according to the axes I, II, III, IV described above, the two handlebar half-portions 160 and the pedals 18, the completely folded configuration of the bicycle illustrated in Figure 7 presents particularly limited overall dimensions, enabling easy transportation of the bicycle B by a user.

Each of the aforesaid folding axes I, II, III, IV is defined by an articulated connection between a first part and a second part of the frame T. Associated to each articulated connection is a device for quick locking and unlocking of the articulated connection. The locking and unlocking devices include respective actuation levers (not illustrated in the drawings that show the bicycle B), which can be operated by the user. With particular reference to Figure 13, which is a sectioned view of a locking and unlocking device D, a cam member 20 is rotatably mounted on one of the two parts of the articulated connection and can be displaced by means of an actuation lever 19, against the action of spring means 21 , between a released, unlocking, position and a locking position, in which the cam member 20 engages against a striker element 22 carried by the other part of the articulated connection.

Thanks to the characteristics described above, the folding bicycle according to the present invention can be implemented in particular in the form of simple bicycle with pedal assistance, at the same time being functional and having a low weight and minimum overall dimensions in the folded condition. At the same time, the bicycle in its condition of normal use is similar, both at the level of design quality and as regards performance, to a high-range bicycle of the non-folding type.

Of course, without prejudice to the principle of the invention, the details of construction and the embodiments may vary widely with respect to what has been described and illustrated herein purely by way of example, without thereby departing from the scope of the present invention.