Collapsible flip-pivot bicycle.

(b) Classification of the invention:

Bicycle collapsable about two or more axes.

(c) Relevant existing technical solutions:

The most common method of collapsing a bicycle is when the bicycle is folded in half about an axis roughly perpendicular to the ground, by the hinge placed on the frame. This method is typically - but not exclusively - applied in the smaller size (20-inch or less wheel-diameter) bicycles. The disadvantage of this method, that it results not the most compact size (since the distance of the folding axis to the periferic of the distant wheel is minimum the half of the distance between the periferics of the wheels), and this method is not optimal in terms of rigidity either, as significant static and dynamic forces arise where the folding hinge is. Lot of manufacturers offer bicycles with this folding method.

The larger bikes are very rarely is offered in collapsable deign. If so, the typical folding method of them is that the complete rear/drinig- wheel assembly can be flipped sideways forward along the axis of the seatpost.

The disadventage of this method is, that in order to achieve the most compact size the steering- wheel has to be dismounted and re-mounted to the folded frame, (e.g. EP0080792 Bl).

Beyond the above, there are also folding bicycles flipping over underways (e.g. EP0026800 Bl), where the complete rear/driving- wheel assembly can be flipped underways forward along the axis of the crank-shaft (or nearby to it) to beneath the main- frame and right behind the steering-wheel, and the steering-wheel can folded back sideways by a hinge next to the flipped rear- wheel.

Disadvantage is that it can be applied to only with small wheel sizes, and the main-frame has to run relatively high, since the flipped rear- wheel has to fit beneath the main- frame.

An also commonly known collapse method, when the bike frame is an upwardly open arc (possibly bending back on the wheels on one or both ends with inflexion point(s)) with the radius more of the wheels, where the wheels can be flipped up inside the frame arc at the ends of the arc (or at the inflexion point(s)) along two axes which are parallel to the closest section of the wheels' periferics, but offset to each-other in two different planes.

The disadvantage of this method is that flipping axis of the rear/driving- wheel assembly is relatively far from the ergonomically ideal point of the crankshaft, hence the the rear/driving- wheel assembly has to have a bigger own frame where the carnkshaft can positioned ideally, otherwise the construction is suit for electric drive the most. (e.g. WO 2011029750 Al).

In addition to the above common folding methods, there are lot of folding bikes with very complex, complicated and expensive folding mechanisms.

In addition to, in the most of the folding bikes, the frame of the rear/driving-wheel and the headset are connected with a single frame-tube only, which results in less rigidity of the bike, or requires heavy reinforcement with additional weight and cost. (d) Challange of the invention:

The subject of the invention is a collapsable bicycle, foldable about multiple axes, hereinafter referred as flip-pivot bicycle which is foldable by a new method, and have the following benefits:

• Can be folded simplier and in more compact size, particularly - but not exclusively - in bigger wheeled bicycles (above 20-inch wheel diamater, e.g. in 24-, 26-and 28-inch sizes), making them easier transportable either on public transport vehicles, or in car trunks.

• Collapsable ergonomically/comfortably without the removal of the front wheel.

• The folding method is applicable even with one- or two-side fork wheel-suspension.

• In addition, the bicycle can be equipped with an extra frame-brace without impede the folding process, thus providing higher mechanical strength to the structure without significant additional weight.

(e) Solution in accordance with claims:

The collapsible flip-pivot bicycle is a bicycle foldable about multiple axes, which consists of three rigid-itself frame-segments, i.e.

- the steering- frame-segment (3), comprising turnably the steering wheel assembly including i. e. the stem (16), the fork/forks (8) and the steering-wheel (6),

- the driving-frame-segment (1) comprising the driving-wheel (7),

- and the central-frame-segment (2), which connects the driving- frame-segment (1) and the steering-frame-segment (3)

characterized in that

the central-frame-segment (2) and the driving-frame-segment (1) are connected to each-other pivotably above a pivot-axis (4), which pivot-axis (4) is perpendicular to the plane of the parallelly positioned wheels (6, 7), or forms an angle of maximum 45 degree with this perpendicular, and

the central-frame-segment (2) and the steering-frame-segment (3) are com ected to each-other turnably along a flip-axis (5), which flip-axis (5) is in the plane of the parallelly positioned wheels (6, 7), or is parallel to this plane, or forms an angle of maximum 45 degree with this plane.

(Figures 1-3 and Figures 4-7)

The function of the flip-axis (5) is to relocate the wheel distant to the pivot-axis (4) (Typically the steering wheel (6)) as close (or approximately as close) to the pivot-axis (4) as the other wheel (Typically the driving-wheel (7)) is. (Figure 2)

Consequently, the flip-axis (5) is approximately the median-perpendicular of the centers of the unfolded and desired folded positions of the flipped wheel (Typically the steering wheel (6)).

Based on the above, theoretically the flipped wheel can be relocated anywhere on a circle concentric to the pivot-axis (4) with the radius equal (or close to equal) to the distance of the other wheel, as can have infinite position on this circle.

However in the most ideal case, the folded and the unfolded positions of the flipped wheel do not intersect each-other, but are the closest to each other as much as possible, thus the flip-axis (5) is the closest to the periferic of the wheel, resulting the most compact folded dimension.

Coaxiality of the wheels when folded:

Depending on whether the flip-axis (5) relocates the wheel distant to the pivot-axis (4) exactly as close to the pivot-axis (4) as the other wheel is, or just near as close, the axes of the wheels in folded state are coincident or not.

The coaxiality of the folded wheels results better maneuverability, but less compact size due to that the widest point of a bicycle wheel is typically at its axis.

Therefore, the slightly not coaxial position of folded wheels is also a considerable design solution. (Figure 14.) Offset of the plane of the wheels during folding:

If the flip-axis (5) were in the plane of the parallelly positioned wheels (6, 7), and the pivot-axis (4) were perpendicular to it, and the central-frame-segment (2), were not possible to be offset to the driving-frame-segment (1) along the pivot-axis (4), then the bicycle could not be folded, as the in the folded position the wheels were in the same plane.

To eliminate this above coincidency, one of the following solutions or a combination of them is needed:

• One of the fundamental solution is to offset the flip-axis (5) from the plane of the parallelly positioned wheels (6, 7). For this purpose the following solutions or a combination of them is needed:

> The flip-axis (5) is inside the frame segments (2, 3), but the frame segments (2, 3) or the section of them where the flip-axis (5) is located is outside of the plane of the parallelly positioned wheels (6, 7). This asymmetrical design imply some torsion load on the frame but it is not significant. (Figures 4-7)

> The flip-axis (5) is out of the plane of the parallelly positioned wheels (6, 7), and the frame segments (2, 3) or the section of them where the flip-axis (5) is located is duplicated, and one of the frame-branches incorporates the pivoting flip-axis (5), while while the other frame-branch is designed with releaseably fixed connection (e.g. with releasable fast-lock or releasable latch) at the connection of the frame segments (2, 3). (Figures 8 and 9)

> The flip-axis (5) is out of the plane of the parallelly positioned wheels (6, 7), but where the central-frame-segment (2), and the steering-frame-segment (3) are align with that plane. (The flip-axis (5) does not have statical role when the bicycle is unfolded, and when the statical and dynamic loads are beared by the releaseably fixed connection (e.g. with releasable fast-lock or releasable latch) which connets the central-frame-segment (2) and the steering-frame-segment (3) . This case the flip-axis (5) should be designed only for the statical loads arising during the folding of the bike. (Figures 10 and 11)

• The central-frame-segment (2) and the driving-frame-segment (1) which are connected by and can pivot above the pivot-axis (4), can be offset along the pivot-axis (4). (Figures 12-13)

• The flip-axis (5) forms an angle of 0-45 degree with the plane of the parallelly positioned wheels (6, 7) and/or pivot-axis (4) forms an angle of 0-45 degree with the perpendicular of this plane, thus the plane of the steering-wheel (6) will move out of the plane of the driving- wheel (7) during the folding process. (Figures 15 and 16)

• The steering-wheel (6) is designed to be pivotable along an axis which is out of the plane of the steering-wheel (6) itself, which axis can be e.g. one of the forks (8), when the fork- crown item which connects the forks (8) to the stem (16) consist of two releaseably fixed parts splitted horizontally. (Figures 17 and 18)

Naturally the one-side fork (8) suspension results more compact foldeded size. (Figures 4-7)

Extra frame-brace (9)

The rigidity of the flipping-pivoting bicycle can be enhanced by an extra frame-brace (9) which connects the driving- frame-segment (1) either with the central-frame-segment (2), or with the steering-frame-segment (3), with hinge or tenon connection on the one end, and releaseably fixed connection (e. g. releasable fast-lock or releasable latch) on the other or on both ends.

The complementary frame-brace (9) can be fixed to the driving- frame-segment (1) in multiple positions on the alternative frame-brace fixing points (10), and/or can consist of two or more longitudinally telescoping pieces sliding into or side-by each-other. Thus the distance between the seatpost (15) and the stem (16) can be varied in wide range giving significant flexibility to set the most comfortable seating position. The extra frame-brace (9) can serve for fixing of the saddle (14), or of the structure incorporating the saddle (14), or of the seatpost (15). (Figures 19-20)

Central suspension

Beside the basic rigid connection of the central-frame-segment (2) and the driving-frame-segment (1) of the unfolded bicycle, the bicycle can be equipped with central suspension, where the flexible- item can be either at the pivot-axis (4) or incorporated in the extra frame-brace (9), and this flexible- item can be de-activated during the folding of the bike above the pivot-axis (4).

The central suspension can substitute and eliminate the necessity of the normal spring item(s) in the fork(s) (8) of the steering-wheel (6).

Location of the Drive shaft ( ^" 11

Ideally the crank-shaft (11) is located on the driving-frame-segment (1) even - but not necessarily - in align with the pivot-axis, as in this case the crank-shaft (11) distance to the axis of the driving- wheel (7) does not change during the folding. (Figures 4 to 7 and Figures 19-20).

If the crank-shaft (11) is located on the central-frame-segment (2) it's distance to the axis of the driving-wheel (7) varying during the folding, which can be compensated with one of the following solutions:

• In case of chain drive, the drive can be transmitted in two stages through an ancillary chain- wheel which axis is coaxial with the pivot-axis (4).

• In case of chain drive, the other solution is to apply a derailleur with the necessary flexiblity to compensate the varying distance during the folding.

• In case of Cardan-shaft drive the shafts have to be telescopic, and is preferred to be inline with each-other when the bicycle is unfolded to eliminate the sinusoidal transmission of the Cardan-drive when the shafts are in angle.

Shape of the frame-segments (1, 2, 3)

Ideally in order of the most compact collapsed size, the frame-segments (1, 2, 3) in the collapsed state should follow (lean on) as closely as possible the arc of the wheels.

Of course, the frame-segments (1, 2, 3) can be straight/angular as well, while keeping in mind the ideal position of the flip-axis (5).

Pedals (13) and crank-arms (12)

In nomial condition, the crank-arms (12) mounted on two sides of the common crank-shaft (11), are in 180 degrees to each-other, and the pedals are mountes outward on the outside of their respective crank- am (12).

However, more compact folding size is achievable when the crank- arms (12) can be mounted to the crank-shaft (11) even in less than 180 degrees to each-other, by using releasable fast-lock fixing. It is also expedient in order of the most compact size, when one or both crank-arms (12) can be mounted to the crank-shaft (11) even with pedals (13) inward, and/or one or both pedals (13) can be re-fixed on the inside of the respective crank-am (12) by using releasable fast-lock fixing. (Figures 6 and 7)

Saddle (14) and its fixing

In order to further decrease the folded size of the bicycle, the seatpost (15) may run even out of the plane of the parallelly positioned wheels (6, 7), and can be fixed to the driving- frame-segment (1), and/or to the central-frame-segment (2), and/or to the extra frame-brace (9).

Collapse of the stem (16)

In order of the compact size the stem (16) either

• can be folded down side by the wheel in the usual way by a hinge approximatelly perpendicular to the stem (16) and in an angle of 45-degree to the plane of the steering- wheel (6), or

• if the stem (16) is running out of the plane of the steering-wheel (6) it is slidable by along its own axis into one fork (8) of the steering-wheel (6) or next to it. (figures 21-24)

(f) List of the attached figures with denomination of the tags:

The item numbers in drawing names:

1. Driving- frame-segment

2. Central-frame-segment

3. Steering- frame-segment

4. Pivot-axis

5. Flip-axis

6. Steering-wheel

7. Drive- wheel

8. Fork

9. Frame-brace (fixed or variable length)

10. Frame-brace-alternative-fixing-points

11. Crank-shaft

12. Crank-arm

13. Pedal

14. Saddle

15. Seatpost

16. Stem

Attached figures:

Figure 1, 2, 3: Schemitc figure showing the collapsing method of the bike (the main claim).

Figure 4, 5, 6, 7: Example for a complete bicycle showing the main and some sub-claims.

Figure 8, 9: Schematic figure showing a sub-claim about one possibe way of offset the plains of the wheels.

Figure 10, 11 : Schematic figure showing a sub-claim about one possibe way of offset the plains of the wheels.

Figure 12, 13: Schematic figure showing a sub-claim about one possibe way of offset the plains of the wheels.

Figure 14: Schematic figure showing the benefit of the non-coaxially positioned wheels in collapsed status.

Figure 15, 16: Schematic figure showing a sub-claim about one possibe way of offset the plains of the wheels.

Figure 17, 18: Schematic figure showing a sub-claim about one possibe way of offset the plains of the wheels.

Figure 19, 20: Shows one of the sub-claims the frame-brace (9).

Figure 21, 22, 23, 24: Shows one of the sub-claims the slidable stem (16).