Patent Application
20240336322
Recumbent bicycles tend to be very long and have a long wheelbase especially when compared to a typical upright bicycle. This makes transporting and shipping them more difficult often requiring very large oversize boxes, This not only increases the cost of shipping a bike from the manufacturer to either a retailer or a purchaser, but also makes it more expensive for a cyclist to travel to cycling events across the country. If the cyclist is driving to an event, it may be difficult to fit the bicycle, even if the wheels are removed, in many vehicles. If the cyclist is flying, the oversize luggage cost may be substantial if not prohibitive.
Further, on a typical recumbent frame as well as most bicycle frames, parameters, such as the wheelbase, trail, and head tube angle, are fixed. A cyclist who desires a quick handling bike for certain situations, such as racing, or a more stable bike, such as for touring, typically has to purchase separate frames with the desired combination of these parameters, and in most instances for the sake of convenience build each up into a separate bicycle, If the cyclist is traveling to an event in which he/she desires to have bikes with both sets of handling characteristics, he/she must transport both.
While bicycles with folding or uncoupling frames are known that can solve the transportation length issue, folding or coupling joints are known to present weak points on the frame and may induce undesirable flex into the frame at the connection points. However, these frames do not allow for the bicycle's parameters, such as wheelbase and head tube angle to be adjusted.
Embodiments of the present invention comprise a front wheel drive recumbent bicycle frame wherein the wheelbase is adjustable between a fully extended position and a fully retracted position by adjusting the length of a telescoping main tube assembly. Importantly, when built into a bicycle, the main tube rises as it extends rearwardly such that it forms an acute angle of 10-30 degrees relative to a flat underlying surface (or an imaginary line running through the centers of the frame's dropouts. Accordingly, the adjustment of the frame's and bicycle's wheelbase also changes several other parameters including the head tube angle and the related trail measurement, such that shortening the wheelbase also acts to steepen the head tube and reduce trail.
Embodiments of the frame and bicycle typically include a seat that is pivotally attached to the frame at two or more locations, permitting the angle of the seat to be adjusted relative to the ground surface.
In other embodiments of the frame, the rear stay assembly can pivotally adjust and be fixedly secured at its front end where it connects with the rear end of main tube. Depending on the embodiment, the pivotable rear stay connection may be provided with the telescoping main tube or in conjunction with a fixed length main tube. By adjusting the position of the rear stay assembly on a frame that has an angled main tube, the wheelbase can be lengthened or shortened while also changing the head tube angle and the trail.
Advantageously, a cyclist that enjoys both riding fast (or racing), and more relaxed riding, such as touring or commuting can relatively quickly and easily adjust embodiments of the frame and bicycle for either circumstance negating the need to either have multiple bikes or settle on a compromise frame geometry that may not do either task as well as possible but can be used for both albeit at a reduced level of effectiveness. The adjustable frame also offers the advantage of permitting a user to make the frame and or bicycle as short as possible for transporting the bicycle to events whether the bike is packed in a box or shipping container for transport, or the bike is stowed in the trunk or back of an automotive vehicle.
The terms and phrases as indicated in quotes (“ ”) in this section are intended to have the meaning ascribed to them in this Terminology section applied to them throughout this document including the claims unless clearly indicated otherwise in context. Further, as applicable, the stated definitions are to apply, regardless of the word or phrase's case, to the singular and plural variations of the defined word or phrase.
The term “or” as used in this specification and the appended claims is not meant to be exclusive, rather the term is inclusive meaning “either or both”.
References in the specification to “one embodiment”, “an embodiment”, “a preferred embodiment”, “an alternative embodiment” and similar phrases mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least an embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all meant to refer to the same embodiment.
The term “couple” or “coupled” as used in this specification and the appended claims refers to either an indirect or direct connection between the identified elements, components or objects. Often the manner of the coupling will be related specifically to the manner in which the two coupled elements interact.
Directional and/or relationary terms such as, but not limited to, left, right, nadir, apex, top, bottom, upper, lower, vertical, horizontal, back, front and lateral are relative to each other and are dependent on the specific orientation of an applicable element or article, and are used accordingly to aid in the description of the various embodiments and are not necessarily intended to be construed as limiting.
Unless otherwise indicated or dictated by context, the terms “approximately” and “about” mean +−20%. Unless otherwise indicated or dictated by context, the term “substantially” means +−10%. The term “generally” means for the most part.
The term “wheelbase” refers to the distance between the front and rear wheel axles of a bicycle. On a bicycle frame, the wheelbase comprises the distance between the center of the respective front and rear dropouts.
The “head tube angle” refers to the acute angle the axis of the head tube makes with a horizontal ground surface on which the bicycle rests in an upright position sporting front and rear wheels of a desired and/or designed for diameter. Generally, a steeper angle results in a bicycle with quicker steering characteristics compared to a shallower angle.
The “trail” of a bicycle follows from the head tube angle and comprises the distance between the point where a vertical line passing through the front axis of the front wheel intersects a flat ground surface, and the point where the head tube axis intersects the ground surface. Less trail generally results in a quicker steering bicycle compared to a longer trail.
The “main tube angle” as used herein refers to the angle formed between the effective center axis of the main tube and a line parallel with a horizontal ground surface on which the associated bicycle rests. On bicycles utilizing front and rear wheels of the same overall diameter, the main tube angle also comprises the angle formed between the center axis of the main tube and an imaginary line that passes through the centers of the front and rear dropouts.
A front triangle assembly 115 of a front wheel drive recumbent frame and bicycle is also described in detail in U.S. Pat. No. 7,753,388 entitled Front Wheel Drive Recumbent Bicycle, which is hereby incorporated by reference. The triangle includes a pivotal front fork 145 having left and right fork blades each terminating at front dropout 185 designed to receive the axle of the front wheel 120 therein. The fork blades are joined at a proximal end wherein a steerer tube (not shown) that extends generally upwardly passing through and substantially contained in a head tube 150 of the main frame 115 to which the steerer tube is pivotally attached. The top end of the steerer tube is coupled to a telescoping control tube 155 characterized by a handlebar mount at one end and a bottom bracket mount at its other forwardmost end. As can be appreciated, the handlebar 140 is mounted in a handle bar mount; and a bottom bracket is received in the bottom bracket mount, which rotatably attaches the bicycle's crankset 135 of the drivetrain to the front triangle. The telescoping nature of the control tube permits for adjustment of both the distance between the seat 130 and the crankset and the distance between the seat and the handlebar permitting a cyclist to fit the bicycle to his/her liking. These adjustments do not, however, provide for changing the operational or performance characteristics of the bicycle. The pair of chainstays 160 extend between the forwardmost end of the control tube and the distal ends of the fork blades to complete the front triangle assembly.
Operationally, the cyclist pushes the pedals 205 attached to the ends of the crankset's crankarms, which in turn causes the movement of the looped chain 225 to turn a gear of a gearset 230 attached to a hub of the front wheel 120 propelling the bicycle forward. The chain can be moved between the gears of the gearset using a derailleur (not shown) operated by a lever (also not shown) typically located on the handlebar 140. Steering the bicycle is accomplished by pivoting the front triangle relative to the main frame 110 and the rear wheel 125.
As can be appreciated, several variations of the front triangle assembly are known, and each of these variations can be used in embodiments of the present invention. Several of these variations are presented at www.cruzbike.com. For example, in one variation of the front triangle assembly, the control tube rearmost end mounts directly to a steerer tube, and the handlebar is mounted to the steerer tube and not the control tube. Ultimately, the front triangle assembly on embodiments of a front wheel drive bicycle is provided to facilitate steering of the bicycle and include a drivetrain for propelling the bicycle.
The main frame 110 as best shown in
The main tube assembly comprises front and back tubular portions 175&190 with the back tubular portion 190 being capable of sliding in out of the front portion 175 to set an overall length of the main tube. A clamping mechanism 200 is provided that is usually attached to the front portion to secure the back portion to it in a desired position. The nesting front and rear tubular portions can be of any cross-sectional shape, but are often not fully round so that the portions will not rotate along their axes relative to each other thereby helping maintain alignment of the rear dropouts 180 with the front dropouts 185.
Of important note, the main tube assembly extends rearwardly and upwardly from its junction with the front tube 170 to its junction with the rear chainstays 165. The main tube assembly forms an acute main tube angle 530 relative to a horizontal imaginary line 535 drawn through the center of dropouts 180 & 185 as illustrated in in
The rear of the main tube's back portion 190 is attached to the pair of rear stays 165 between which a rear wheel 180 can be received and secured. In one embodiment the rear stays are fixedly attached to the main tube's back portion, but in other variations, such as presented in
The recumbent seat/backrest 130 is adjustably attached to the main frame 110 by way of a pivotal mount 210 on the front tubular portion 175 and a pair of struts 215 with one end of each strut configured for pivotal connection to a mounting flange 220 on each rear stay 165 and an opposing end for pivotal connection to the back of the seat 130. Depending on variations, the struts can be of a fixed length or length-adjustable. Accordingly, as the length of the main tube 160 is lengthened or shortened, the relative positioning and orientation of the seat remains fixed relative to the drivetrain and the ground; or the seat/backrest can be adjusted by changing the length of the struts 215.
In use, the rear portion 190 is slid inwardly or outwardly relative to the front portion 175 of the main tube assembly 162. As can be appreciated when fully extended a suitable section of the rear portion, such as 4″, must remain received in the front portion to ensure the frames overall structural integrity. Once the desire position is achieved, the two portions are fixedly secured to each other using the clamping mechanism 200.
The effect of lengthening or shortening the telescoping main tube assembly 160 is illustrated in
In
To either lengthen or shorten the wheelbase 520 & 555 of the frame 105 or bicycle 100, the user first loosens the main tube clamp 200 to permit the front and rear tube portions 175&190 to slide freely relative to one another. In some variations, the user may also loosen one or more of the bolts securing the seat 130 and/or the rear struts 215 to the frame so that the seat may freely pivot as the length of the frame is adjusted. The rear tube portion is then slid inwardly or outwardly until the desired wheelbase is achieved, and finally the clamp and seat mounting bolts are tightened.
To prepare a bicycle for transport whether to place the bike in the back of a vehicle or package it in a box or container, the foregoing procedure is followed except the main tube assembly 162 is shortened as much as possible. Depending on the space in which the bicycle is to be received, the user may also remove one or both of the front and rear wheels and the seat.
The various embodiments and variations thereof, illustrated in the accompanying Figures and/or described above, are merely exemplary and are not meant to limit the scope of the invention. It is to be appreciated that numerous other variations of the invention have been contemplated, as would be obvious to one of ordinary skill in the art, given the benefit of this disclosure. All variations of the invention that read upon appended claims are intended and contemplated to be within the scope of the invention.
This application claims priority to and fully incorporates by reference U.S. provisional patent application No. 63/456,840 filed on Apr. 4, 2022 that has both the same title and inventor as the present application.
| Number | Date | Country | |
|---|---|---|---|
| 63456840 | Apr 2023 | US |
