Patent Application
20050001404
The present invention generally relates to folding bicycles that can be folded into a relatively compact arrangement, and unfolded for riding.
Bicycles that can be folded have an advantage of a relatively compact arrangement for storage or transport, making them popular with users wishing to reduce storage space, such as commuters, recreation enthusiasts, and campers, among others. Known folding bicycles have a myriad of shortcomings when compared with standard non-folding bicycles. For example, known folding bicycles have a frame of two or more pieces, which can be dismantled, folded or telescopically shortened. In some known folding bicycles, the folded dimensions can be further reduced via removal of their wheels.
In some conventional bicycle folding joints are situated in the central area of the frame, such as within one or more of the down tube, top tube, seat tube and head tube, or bearing tube. A disadvantage of such an arrangement is that the frame's rigidity is reduced, which can detrimentally affect pedaling efficiency, and overall stability.
Another disadvantage associated with such known folding bicycles is that the joints that enable folding can develop a gap, or “play” over a period of usage. This play results in a bicycle that flexes, reducing pedaling efficiency, as the force applied to propel the bicycle is partially absorbed by the flexing joints. In addition, the joints themselves can be weak points in the bicycle, and can cause structural failure, instability or other undesirable riding characteristics.
A further disadvantage is that known folding bicycles have frames that frequently are smaller than the frames of a comparable standard non-folding bicycle. This reduces the ergonomic suitability for a rider. A result of this for many riders is a decrease of the distance that can be ridden with comfort. Riding discomfort can decrease pedaling efficiency, and decrease riding characteristics are less favorable due to the different position of front wheel and smaller wheel size compared to the non-folding bicycles.
Therefore, there exists a need for a folding bicycle that is ergonomically comfortable when riding, optionally has a unitary central frame structure, optionally can be readily folded into a compact arrangement, and/or optionally can maintain its structural rigidity and integrity despite repeated folding and unfolding.
The present invention alleviates to a great extent the disadvantages of known folding bicycles, some of which are discussed above, by providing a bicycle that is foldable into a compact size, while still having a central frame without any folding joints. The foldable bicycle of the present invention, preferably is foldable while generally providing a riding experience and durability of a standard non-folding bicycle.
One embodiment of the present invention includes a central frame assembly of a down tube, a seat tube, a top tube and a bearing tube, wherein the down tube, seat tube, top tube and bearing tube are substantially fixed relative to each other. This arrangement can promote ergonomic riding characteristics of a non-folding bicycle.
The foldable elements of present invention optionally include a foldable front-fork assembly, a foldable rear-wheel assembly and a foldable handlebar assembly. Although each of these assemblies are optional features of the present invention, they operate together to reduce the folded size of the foldable bicycle, rendering it for example more easily transportable. The optional front-fork assembly mounts the front wheel on its lower end, and is jointed at or near a connector strut. In operation, the front fork assembly includes linking bars connecting the upper end at the frame with the wheel, at its axle. The joint can be operated to unlock and allow the front fork assembly to rotate about the joint, in the direction of the down tube assembly of the frame. The down tube of the frame preferably has two spatially separated portions spaced apart from one another. So, when the front fork assembly is rotated about the joint, the wheel can fold into the area between the separated portions, thereby rotating into the center of the frame, through the two spaced apart portions of the down tube. Alternatively, the wheel and front fork assembly can be rotated 180° prior to being folded about the joint.
The optional handlebar assembly also serves to reduce the folded dimension of the foldable bicycle. In particular, the handlebars are mounted to a tube in a locked, but unlockable fashion. When it is desired to fold the bicycle, the handlebars are unlocked, and rotated downwards, preferably to a position that is within the area of the central portion of the frame. In a preferred embodiment, the handlebars are fully turned 180° prior to folding, and the handlebars are then unlocked and rotated downwards to a position in which one handle grip is on the left side of the central portion of the frame, and another handle grip is on the right side of the central portion of the frame. Then, using a lockable joint, the respective handlebars can be folded inwards towards each other, and can be folded inwards a sufficient amount so that the handle grips cross one another.
The optional rear wheel assembly also serves to further reduce the folded dimension of the foldable bicycle. In this embodiment, a strut assembly descends at an angle from beneath the seat to the rear wheel axle. Preferably the strut assembly includes spatially separated, or parallel, bars, between which the rear wheel is mounted. At a location between the seat and the rear wheel axle, the strut assembly includes a locking assembly. When the locking assembly is released, the rear wheel rotates upwards, between the spatially separated bars of the strut assembly. In a preferred embodiment, the compactness of this arrangement can be enhanced by using dual transmission chains, with an intermediate sprocket. The chain stays, together with the rear wheel, are foldable upwards toward the seat. To facilitate the folding of the chain stays and the rear wheel, the transmission from the chainring to the sprocket is complemented by two sprockets and a shaft, i.e. consists two chains in series, which results in an additional transmission ratio. The shaft also serves as a pivot, around which the chain stays and the rear wheel fold. The front chain remains between the front chainring and the intermediate sprocket, on the shaft, while the rear chain remains between the intermediate sprocket and the rear sprocket, and shifts upwards together with the chain stays and the rear wheel without changing the distance between the front sprocket and the rear sprocket. In this embodiment, the rear wheel is rotated about the intermediate sprocket when folding the wheel upwards. The chain stays, together with the rear wheel, is foldable upwards toward the seat. In riding position, power is transmitted via a chain from a pedal sprocket to the intermediate sprocket and then via a second chain from the intermediate sprocket to a rear wheel sprocket mounted at the rear wheel axle. If the rear wheel is removed, the length of the bicycle can be further reduced in the folded position.
To reduce the width of the folded bicycle, the pedals can also be folded.
According to one embodiment, ratios of distances between and among various locations of the bicycle are within predetermined ranges providing examples of configurations providing relatively more stable foldable bicycles and thus a more comfortable and smoother ride. It should be understood that although ranges of ratios are provided for examples of embodiments, foldable bicycles in accordance with the present invention optionally can have ratios within or outside of the ranges provided.
In an alternate embodiment of the present invention, a foldable tandem bicycle is provided. In this arrangement, a second seat is situated behind the front seat, and a second set of pedals is provided. In the tandem arrangement, a second set of pedals is not necessarily required. For example, footrests can be added at any suitable position for receiving a second passenger's feet, but preferably in a location safely away from operative components or the first pedals. In addition, as an alternative to the second seat, or in addition to the second seat, other optional components can be added, such as a child seat, basket, briefcase holder, rack, etc. Such components can be attached in a similar fashion and location as the second seat.
In a further embodiment, the bicycle can be equipped with a motor providing torque at one of the sprockets or the chainring.
These and other features and advantages of the present invention will be appreciated from review of the following detailed description of the invention, along with the accompanying figures in which like reference numerals refer to like parts throughout.
It will be recognized that some or all of the Figures are schematic representations for purposes of illustration and do not necessarily depict the actual relative sizes or locations of the elements shown.
In the following paragraphs, the present invention will be described in detail by way of example with reference to the attached drawings. Throughout this description, the preferred embodiment and examples shown should be considered as exemplars, rather than as limitations on the present invention. As used herein, the “present invention” refers to any one of the embodiments of the invention described herein, and any equivalents. Furthermore, reference to various feature(s) of the “present invention” throughout this document does not mean that all claimed embodiments or methods must include the referenced feature(s).
The present invention relates to a foldable bicycle including a frame geometry providing various components in the same relation to one another both in the folded and unfolded conditions. As defined herein “frame geometry” refers to the arrangement of tubes that make up the bicycle frame. The relationship between the tubes comprising the bicycle frame creates a specific overall “frame geometry.” One feature of the foldable bicycle of the present invention is that the frame core preferably is of a unitary construction, i.e. containing no joints connecting moving parts.
Referring to
A second embodiment of the present invention is illustrated in
Optionally, a single seat bicycle can be converted to a tandem folding bicycle, by positioning the second seat tube 45 between the two upper seat stay tubes 75, 80 that comprise the upper seat stay 85. Attached to the upper seat stay 85 is the second seat tube fastener receiver 55, which is sized to receive the second seat tube fastener 50. The bottom end of the second seat tube 45 is positioned against the second seat tube support 60, located between the two forward bottom bracket tubes 90, 95, shown in
Referring now to
In a further embodiment of the tandem bicycle, the second seat 40 is positioned so that a passenger in the seat 40 can face backwards. Optional footrests may be provided to allow a comfortable resting place for the rear-facing passenger's seat. Likewise the seat 40, whether front or rear facing may include amenities such as a backrest enhancing passenger comfort.
Referring to
As shown in
In one embodiment, the respective handlebar elements 140 can be folded inwards as well, in order to further decrease the folded size of the bicycle. In this embodiment, handlebar pivot axes 130 are provided at the intersection of the handlebars 140 and the mounting member 135. One embodiment handlebar latch 145, that releases the handlebar elements 140, is a hook-and-loop type, but other type of latches may be employed, such as a quick-release latch, or any other type of suitable latch or fastener.
Referring now to
Referring again to
In a preferred embodiment the stirrup latch 180 is a spring lock, but other types of latches and fasteners, such as hook-and-loop, or quick-release fasteners may be employed. The front fork assembly 115 is folded by rotating the front fork 150 approximately 180 degrees. The stirrup latch 180 is then released, freeing the stirrup 160, and allowing the rider to rotate the swing arm 155 and stirrup 160 about the fork pivot axis 157, as shown in
Examples of folded configurations are illustrated in
An alternative embodiment front fork assembly 115 may include two springs or shock absorbers 14, as shown in
On feature of the foldable front fork assembly 155 is that the “head angle” of the bearing tube can be configured similar to the head angle of a non-folding bicycle. The head angle determines the front fork rake angle, which affects steering “quickness.” That is, the steering of the present invention will feel normal to a rider accustomed to a non-folding bicycle, in contrast to conventional folding bicycles, that have a steeper head angle, which results in a steep front fork rake angle. This can be implemented to create relatively quick steering, resulting in a nervous, or edgy steering feel as desired.
An optional rear wheel assembly 120 also is provided. Any assembly may be used that is suitable for mounting the rear wheel rotatably with respect to the frame 12, and for mounting as desired one or more seat assemblies. In the illustrated embodiment, the seat stay is divided into an upper seat stay 85, and a lower seat stay 185. The upper seat stay 85 may optionally have two upper seat stay tubes 75, 80, shown in
As shown in
In a preferred tandem bicycle embodiment, the diameter of the first sprocket 105 is the same as that of the first middle sprocket 112 and the diameter of the second middle sprocket 114 is greater than that of one or more of the sprockets 237 on the rear hub 235, although any sprocket size can be used that allows the pedal force generated at any of the pedal assemblies 100, 107 to the rear wheel 240.
In one embodiment of the present invention, the rear hub 235 may contain internal gears, or the rear hub 235 may include external gears and a derailleur to move the chain between the gears. In addition, the front sprocket 105 may include additional sprockets beyond the two sprockets 112, 114 in the illustrations. In this way, a variety of gear ratios may be provided. One feature of the present invention is that the two sprocket assemblies 105, 110 provide a gear ratio that may be suitable for most bicycle speed requirements. It should be noted that although chains 225 and 230 are discussed herein as providing mechanism for transmitting force between the respective sprockets 105, 110 and, or the hub mechanism 235 force can be transmitted via any mechanism that allows the forces to be appropriately transmitted from the rider's feet or hands to the appropriately driven wheel or wheels. For example, the force can be transmitted from pedals 100 or 107 via a drive shaft to rear wheel 240 or front wheel 175. Such a drive shaft system is widely known and used, for example in motorized vehicles to transmit propulsive force from an engine to one or more wheels. Alternatively, a power supply 65 may be included for providing a propulsive force. The power supply 65 may comprise an electric or internal combustion motor, that in a preferred embodiment would not increase the folded dimensions of the foldable bicycle 10, or the tandem foldable bicycle 70.
Again referring to
As shown in
In addition, to reduce the width of the foldable bicycle 10, or the tandem foldable bicycle 70, the pedals may also be folded. Moreover, the foldable bicycle 10, or the tandem foldable bicycle 70 may be equipped with an electric or internal combustion motor without increasing the folded dimensions.
Any size wheel diameter can be used that allow the wheels to be appropriately folded using the frame assembly 12 provided. For example, both the front wheel 175 and the rear wheel 240 can be 14 inches or 16 inches in diameter, but other wheel sizes may be employed, such as for example 23 inches in diameter or other sizes. In addition, the foldable bicycle 10 and the tandem foldable bicycle 70 may be equipped with brakes, lights, fenders, a kick stand, and other amenities. Moreover, the frame may be sized to fit a child, or an oversized adult, or the top tube 15 may be positioned closer to the down tube(s) 20, such as traditionally has been provided on female gender-specific bicycles, as shown in
Referring now to
In an alternative embodiment, top tube 15 may be curved, as illustrated in
The top tube 15 optionally may include two spaced apart members 15A, 15B and the seat stay 85 may include two spaced apart seat stay members 86A, 86B. The top tube members 15A, 15B and seat stay members 86A, 86B optionally may be curved from front to rear as described above. It should be noted that although the terms “tube” or “tubes” are used in this description to describe various structural members of the bicycle 10, that any type of member of sufficient strength or other characteristics can be used—such as for example, solid members, beams of various cross-sectional profiles, or tubes (i.e., members defining an interior space). A fastener (or clamp) 210 is provided below the seat 35 that can releasably engage the seat stay 86, or seat stays 86A and 86B. In the unfolded position, the seat stay(s) are held in position by the fastener 210, and in the folded position, the fastener 210 is operated to release the seat stays 86 or 86A, 86B to allow the rear wheal to pivot into its folded position. Examples of a fastener 210 are illustrated in
A front fender 245 optionally can be provided, and the front fender 245 optionally may include a fender stand 250. The fender stand 250 helps to maintain the foldable bicycle 10 is an upright position when in the folded position. The fender stand 250 may be used in combination with a frame stand described in further detail below. Optionally the front fork assembly 115 may be sized to have at least one protrusion 260 extending beyond the circumference of the wheel, and functioning as a stand in the folded configuration—instead of or in addition to the fender stand 250.
Optionally, a frame stand 255 is provided to assist in maintaining a folded bicycle 10 in an upright position. Optionally, it may be attached to a portion of one or both of the forward bottom bracket tubes 90, 95, or in embodiments in which a single forward bottom bracket tube 96 is used, the frame stand optionally may be attached to a portion of it. However, it can be attached at any suitable location where it can assist in maintaining a folded bicycle 10 upright. Optionally, both the frame stand 255 or fender stand 250 and/or fork assembly protrusion 260 as described above may be used in combinations.
According to one embodiment of the present invention, the ratios of distances between and among various locations on the foldable bicycle fall within ranges of desired ratios, such as to provide desired handling, size and riding characteristics. In an embodiment, the ratios of such distances are selected so as to enhance stability, handling and riding characteristics of the foldable bicycle 10 when in the riding position. Sizes of various components, such as, for example, the top tube(s) 15, 15A, 15B, downtube(s) 20, 165, 170, seat tube 25, seat stays 85, forward bottom brackets 90, 95, 96 or rear bottom brackets 200, 205 may be varied, to accommodate various desired bicycle configurations and riding characteristics.
In order to illustrate desired ratios, the following points will be used for discussion:
It should be noted that although various ratios, dimensions and ratio ranges may be provided herein, these are intended only as examples of the invention, and not limitations on particular dimensions or ratios. It should be understood that ratios outside of the ranges of the examples provided herein also can be practiced. Examples of suitable ratio ranges are as follows: ratio of distances A to B and A to C is in a range of 0.67 to 2.01; ratio of distances A to B and B to F in the range of 0.9 to 2.72; ratio of distances A to B and A to F is in the range of 0.54 to 1.64; ratio of distances A to F and B to F is in the range of 0.83 to 2.49; and the ratio of distances A to H and H to C is in the range of 0.50 to 1.5.
One example of the present invention is provided by way of TABLE 1 below. In TABLE 1, the top row and left columns correspond to particular points on the bicycle (or the ground) as listed above. The distances between the points are provided at the intersections of the given row/column. Where the same point is at the intersection, a dot (●) is used to indicate no distance measurement. Although the units for this chart are centimeters, it should be understood that other units may be used and the example is provided to provide relative distances for the purpose of determining ratios. It also should be noted that these distances are provided only as one of numerous possible examples of how the invention can be practiced and that the ratios among the distances can be varied as much as 50% or more. Although examples of ranges of rations among the distances are provided above, other ratios and ratio ranges that characterize the folding bicycle of the present invention can be derived by selecting any combination of distances provided in TABLE 1, determining ratios between the selected distances and selecting a ration range that runs from one-half the ratio to one and one-half times the ratio. In addition, the distances can be scaled up and down to accommodate different size bicycles.
Thus, it is seen that a foldable bicycle is provided. One skilled in the art will appreciate that the present invention can be practiced by other than the above-described embodiments, which are presented in this description for purposes of illustration and not of limitation. The description and examples set forth in this specification and associated drawings only set forth embodiment(s) of the present invention. The specification and drawings are not intended to limit the exclusionary scope of this patent document. Many designs other than the above-described embodiments will fall within the literal and/or legal scope of the following claims, and the present invention is limited only by the claims that follow. It is noted that various equivalents for the particular embodiments discussed in this description may practice the invention as well.
| Number | Date | Country | Kind |
|---|---|---|---|
| SI 200200308 | Dec 2002 | SI | national |
This application is a continuation-in-part of co-pending U.S. patent application Ser. No. 10/461,017, filed Jun. 12, 2003, and entitled “Folding Bicycle” and PCT International Patent Application No. PCT/IB03/01243, filed on Mar. 3, 2003, and entitled, “Folding Bicycle”, both of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10461017 | Jun 2003 | US |
| Child | 10866551 | Jun 2004 | US |
| Parent | PCT/IB03/01243 | Mar 2003 | US |
| Child | 10461017 | Jun 2003 | US |
