Patent Application
20170259869
The present invention in general relates to bicycles, and in particular to improvements in tandem bicycles.
The tandem bicycle is a form of bicycle designed to be ridden by more than one person. The term tandem refers to the seating arrangement that is fore to aft, not side-by-side. Compared to a conventional bicycle, a tandem has double the pedaling power with only slightly more frictional loss in the drivetrain. Tandem bicycles have about the same wind resistance as a conventional bicycle. High-performance tandems may weigh less than twice as much as a single bike, so the power-to-weight ratio may be slightly better than that of a single bike and rider. On flat terrain and downhill, most of the power produced by cyclists is used to overcome wind resistance, so tandems can reach higher speeds than the same riders on single bicycles. However, tandem bicycles may be slower on climbs, in part due to the need for a high level of coordination between the riders, especially if the physical abilities of the two riders are very different, requiring a compromise on cadence.
In conventional tandems, the front rider steers as well as pedals the bicycle and is also known as the captain, pilot, or steersman; the rear rider only pedals and is also known as the stoker, navigator, or rear admiral. On most tandems two sets of cranks are mechanically linked by a timing chain and turn at the same rate. The transfer of power from all pedals to the rear wheel requires a drive train. Typically, the front most crankset turns the timing chain, which in turn connects to the rear crankset, which transfers this power to the drive chain that connects to the rear wheel. This configuration is called crossover rear drive, and requires both of the rear riders crank arms to have chain rings mounted. Tandem riders may choose to synchronize their pedaling through in-phase (IP) or out-of-phase (OOP) pedaling. In in-phase pedaling, each rider's cranks are in the same or opposite clock positions at any point in time. In out-of-phase pedaling, both riders have their cranks in differing non-opposite positions.
Bicycles, including tandem versions, are built on a frame to which wheels and other components are fitted. The frame is typically constructed from a series of tubes arranged as 5 triangles. A diamond frame 10 typically is formed of two triangles, as shown in prior art
Traditional tandem bicycles have certain drawbacks that include a long wheelbase that reduces the portability and maneuverability of the bicycle, as well as storage and transport of the bicycle. The rear rider of a tandem bicycle has no control over the steering of the bicycle, and in general the forward field of vision of the rear rider is impaired by the front rider. Furthermore, besides reducing the rear rider's view, the seating arrangement of a tandem bicycle also separates the riders from each other so that they cannot interact or communicate easily. The separation of the riders on a tandem bicycle is a serious detriment for social or leisure riding. In fact, riders on a tandem bicycle may feel more isolated from one another than if they were riding side-by-side on separate standard bicycles. The lack of the rear rider's control, sense of participation, and separation from their fellow rider is potentially detrimental to their experience of riding a tandem bicycle.
An example of a short tandem that can be ridden by a single rear rider is known for example as the “BUDDY BIKE™” with the first distance between the head tube and front seat post is typical or near Union Cycliste Internationale (UCI) standard teachings, rather the short length of said tandem types is derived by shortening the second distance between the front seat tube and rear seat tube compared to standard length tandems. The short tandem BUDDY BIKE™ has a front distance that is 17 percent greater than the rear distance. While a standard UCI racing tandem has a first distance of 75-90 percent of the second distance. The UCI tandem's first distance is typical of all bicycle prior art. The UCI tandem are not like short tandems, and the second distance is greater in length due to added space for the rear rider to get into a long aerodynamic body shape, thus the first position would be less. As a result the first distance reduction can be construed to be unrelated to frame shortening technology.
Thus, there exists a need for a more compact and easily transportable tandem bicycle that increases the involvement and participation of the rear rider.
A tandem bicycle is provided that is compact and easily transportable, while increasing the involvement and participation of the shorter of the two riders. A tandem bicycle is provided that has a shortened wheelbase between the front and rear wheels that allows a rider to ride comfortably alone from either the front or rear seats, or with a passenger in the front seat. The frame length of a tandem bicycle is comparable to a standard single seat bicycle. The reduced proximity between riders, and the ability to steer from both the front or rear seats on the tandem bicycle improves the level of participation and interaction between the riders. In certain embodiments, the wheelbase is reduced by bringing the front wheel closer to the front seat position. A reduced diameter front wheel is provided to accommodate rotational clearance of the front pedals thereby allowing two riders to ride on bicycle frame with a length common to single rider bicycle.
Various embodiments of the present disclosure will be understood more fully from the detailed description given below and from the accompanying drawings of various embodiments of the disclosure. In the drawings, like reference numbers may indicate identical or functionally similar elements. Embodiments are described in detail hereinafter with reference to the accompanying figures, in which:
The detailed description explains the preferred embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
The disclosure may repeat reference numerals and/or letters in the various examples or Figures. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. Further, spatially relative terms, such as beneath, below, lower, above, upper, and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated, the upward direction being toward the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure.
Unless otherwise stated, the spatially relative terms are intended to encompass different orientations of the apparatus in use or operation in addition to the orientation depicted in the Figures. For example, if an apparatus in the Figures is turned over, elements described as being “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the exemplary term “below” can encompass both an orientation of above and below. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
As used herein, the words “comprise,” “have,” “include,” and all grammatical variations thereof are each intended to have an open, non-limiting meaning that does not exclude additional elements or steps. While compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods also can “consist essentially of” or “consist of” the various components and steps. It should also be understood that, as used herein, “first,” “second,” and “third,” are assigned arbitrarily and are merely intended to differentiate between two or more objects, etc., as the case may be, and does not indicate any sequence. Furthermore, it is to be understood that the mere use of the word “first” does not require that there be any “second,” and the mere use of the word “second” does not require that there be any “first” or “third,” etc.
The terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces. If there is any conflict in the usages of a word or term in this specification and one or more patent(s) or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.
Generally, a tandem bicycle is provided that is compact and easily transportable, while increasing the involvement and participation of the shorter of the two riders. Embodiments of the inventive tandem bicycle have a shortened wheelbase between the front and rear wheels that allows a rider to ride comfortably alone from either the front or rear seats, or with a passenger in the front seat. The frame length of the inventive tandem bicycle is comparable to a standard single seat bicycle. The reduced proximity between riders, and the ability to steer for both the front or rear seats on the inventive tandem bicycle improves the level of participation and interaction between the riders. In embodiments the wheelbase is reduced by bringing the front wheel closer to the front seat position.
It is to be understood that in instances where a range of values are provided that the range is intended to encompass not only the end point values of the range but also intermediate values of the range as explicitly being included within the range and varying by the last significant figure of the range. By way of example, a recited range of from 1 to 4 is intended to include 1-2, 1-3, 2-4, 3-4, and 1-4.
Referring now to
As seen in
In certain embodiments, an angle A1 of between 150 and 170 degrees is defined between the horizon for the orientation shown and the line between the tops of posts 36-36′. The bottom of front seat tube 22′ has a downward extension tube 58 extending below the down tube member 20 that is attached to a front bottom bracket to hold and engage a timing or front crankset 42 and front pedals 44, which drives or turns a timing chain 46 suspended with a timing chain adjuster 48, to adjust the timing chain 46. The timing chain 46 in turn connects to the rear crankset 50 attached to rear pedals 52, which transfers this power to the drive chain 54 that connects to the rear wheel 34 via gear set 56. The rear seat tube 22 holds or engages the rear crankset 50 and terminates at the intersection of the down tube 20 and the rear chain stays 24. Together, the timing chain 46 and drive chain 54 form a power transmission that may be operated by a first and a second rider either individually or together, while seated in the front seat 38′, rear seat 38, or both.
The handle bar 30 is movably connected to the head tube member 16 via stem 62 of the tandem frame. In certain inventive embodiments, the stem 62 may be similar to the up and down adjustable stem found on folding bikes, or the stem 62 can have a hinge 63 for easier transportation in a similar fashion to stems used on folding bikes. Additionally, it can be appreciated that the stem 62 may be adjusted to different angles front to back.
The handle bar 30 is adapted to be manipulated by either at least one of the first or second riders sitting on the front 38′ or rear seat 38 as shown in
In certain embodiments of the tandem bicycle 40, a first distance (L1) between the head tube member 16 and front seat tube member 22′ is less than 75 percent the length of a second distance (L2) between the rear seat tube member 22 and the front seat tube member 22′. The first distance L1 is measured along the axis 74 of the top tube member 18, from the intersection point of the axis 74 and the axis 70, to the intersection point of axis 74 and the axis 72. The second distance L2 is measured along the axis 74 of the top tube member 18, from the intersection point of the axis 74 and the axis 72, to the intersection point of axis 74 and the axis 76. In still other embodiments, the distance (L1) between the head tube member 16 and said front seat tube member 22′ is less than 50 percent the length of the top tube member 18. The tandem with a first distance being less than 75 percent of the second distance or even less than 50 percent of the second distance, thereby providing advantages of handling, transport, and unparalleled utility for the single rider.
In certain embodiments of the tandem bicycle 40, the distance (L1) between the head tube member 16 and the front seat tube member 22′ is less than 14 inches. In other inventive embodiments, the distance (L1) between the head tube member 16 and the front seat tube member 22′ is 6 inches.
In other embodiments of the tandem bicycle 40, a wheelbase distance (L3) measured from the axis of the front wheel 32 to the axis of the rear wheel 34 is 41.5 inches, and the distance (L1) between the head tube member 16 and the front seat tube member 22′ along the top tube member 18 axis 74 is less than 14 inches.
In other embodiments of the tandem bicycle 40, the diameter of the front wheel 32 is less than the diameter of the rear wheel 34.
In other embodiments of the tandem bicycle 40, the front seat tube member 22′ downward extension tube 58 extends below the down tube member 20, with an angle between the riding surface 8 and the down tube member 20 of greater than 20 degrees.
In other embodiments of the tandem bicycle 40, the rear seat tube member 22 has an upward extension tube 60 above the top tube member 18 that engages the rear seat post 36. The upward tubular extension tube 60 is reinforced and serves as a strengthening member for the rear seat post 36.
In an embodiment of the tandem bicycle 40, the front pedals 44 form a set of left and right pedals for the front seat 38′ that define left and right crank rotational planes 82, 84 (see
In an embodiment of the tandem bicycle 40, a rotational axis 70 of the front tube member 16 can be positioned at the angle A3 relative to the riding surface 80, such that the rotational axis 70 can extend through a spacial volume B positioned above the front seat 38′ as shown in
Distance L4 indicates the point above the riding surface 8 that the axes 70 and 72 can intersect. The height (or distance L4) of the intersection point between axes 70 and 72 demonstrates a relationship between the front seat tube member 22′ and the front tube member 16. With the front seat tube member 22′ positioned closer to the front tube member 16 than other tandem bicycles and the front tube member 16 angled at a greater angle A3 than other tandem bicycles, the wheelbase L3 of the tandem bicycle 40 of the current disclosure can be reduced over the wheelbases of other tandem bicycles, while still providing sufficient clearance for the front rider (generally indicated by the volume B) as well as clearance of the front pedals 44 from the front wheel 32. The distance L4 can be on the order of 120 inches or less, which can correspond to the front tube member 16 angle A3 ranging from 70 degrees to 50 degrees. Additionally, the distance L4 can be on the order of 90 inches or less, which can correspond to the front tube member 16 angle A3 ranging from 68 degrees to 50 degrees. These values of angle A3 can provide significant advantages to reducing the overall length of the tandem bicycle 40. Additional clearance advantages can be realized by further angling the end of the fork 28 forward as seen in
Normal or typical head tube angles of tandem or single bicycles are generally around 72 degrees. A ‘front center’ length can be a length from the front axle 33 to a front bottom bracket. Shorter ‘front center’ lengths can improve handling for tandem bicycles. Typical ‘front center’ lengths with wheel diameters of 20 inches would be around 21-24 inches to be compliant with the Consumer Product Safety Commission (CPSC) section 1512
As seen in
In other embodiments of the present invention, a tandem bicycle 40 is provided in which the maximal radius of pedals and cranks intersects the front wheel radius. This is particularly advantageous in an inventive bicycle with front wheel of 20 inches or less. It has been surprisingly discovered that when a wheel is intersecting a crank radius, an increase turn angle is realized as a wheel diameter decreases. To facilitate greater limited steering tube angles or no interference (as per CPSC 1512
In another embodiment, a tandem bicycle 40 is provided with a total top tube length (Ltotal) shorter than 35 inches which is generally the length of an adult single rider bicycle top tubes and is considerably shorter than conventional tandem bicycles. By way of example, a road race tandem has a top tube length of 46 inches, the BUDDY BIKE™ tandem has a top tube length 37 inches, while single rider bicycles have top tube lengths ranging between 28-19 inches.
In another embodiment, the tandem bicycle 40 is provided with a weight distribution similar to the range of single rider bicycles when the tandem is ridden singularly and from the rear position. The length ratio is derived from front axle 33 to rear seat 38 and back axle 35 to rear seat 38. An inventive tandem bicycle with ratio within 30% of a single rider bicycle ratio is also contemplated.
In another embodiment, the tandem bicycle is provided with a Wheelbase to Rear Crank (WRC) ratio similar to the range of single rider bicycles when the tandem is ridden singularly from the rear position while not similar to the range of taught tandems. The WRC length ratio is derived from the distance between the rear axle 35 and rear crankset 50 center point divided by the distance between front and rear axles 33, 35 (or wheelbase). An inventive tandem bicycle with ratio within 30% of a single rider bicycle ratio is also contemplated. An inventive tandem bicycle has a WRC of 0.28 to 0.42, while in other embodiments; an inventive tandem has a WRC range from of 0.30 to 0.39.
In contrast to the present invention, a, tandem bicycle from UCI road race, short BUDDY BIKE™, and Schwinn short tandem T-5 have WRCs of 0.273, 0.273, and 0.25, respectively; a conventional UCI road race bicycle and Schwinn cruiser bike have WRCs of 0.273 and 0.41, respectively. While tandems with WRC ratios similar to non-tandem bicycles have obvious advantages for handling, and although it might seem obvious careful study shows an increased chainstay length is required to counter the long total top tube or first and second distance of tandem bicycles. Chain stay lengthening is counter intuitive to an already long tandem when ridden as a tandem. It is further counter intuitive when the purpose is to make the tandem for single riders where length reduction is more critical.
Thus, a tandem bicycle is provided that can include front and rear wheels 32, 34, each with an axis of rotation 33, 35, a frame 92 suspended between the front and rear wheels 32, 34. The frame 92 can include a top tube member 18 with a longitudinal axis 74, a head tube member 16 with a longitudinal axis 70, the head tube member 16 being positioned at a front end of the frame 92, a front seat tube member 22′ with a longitudinal axis 72, and a rear seat tube member 22 with a longitudinal axis 76. The tandem bicycle can also include a handle bar 30 positioned at the front end of the frame 92 and rotatably mounted to the head tube member 16, where the head tube longitudinal axis 70 intersects the top tube longitudinal axis 74 at a first intersection, where the front seat tube longitudinal axis 72 intersects the top tube longitudinal axis 74 at a second intersection, where the rear seat tube longitudinal axis 76 intersects the top tube longitudinal axis 74 at a third intersection, and where a total effective top tube distance is a first distance along the top tube longitudinal axis 74 from the first intersection to the third intersection. A second distance along the top tube longitudinal axis 74 can be a portion of the first distance, where the second distance along the top tube longitudinal axis 74 is a distance from the first intersection the second intersection, and where the second distance is less than or equal to 14 inches.
For any of the foregoing embodiments, the tandem bicycle may include any one of the following elements, alone or in combination with each other:
The second distance can be less than less than or equal to one-half the length of the first distance, or less than or equal to one-third the length of the first distance, or less than or equal to one-fourth the length of the first distance, or less than or equal to 6 inches.
The tandem bicycle can include a wheelbase L3 that is a distance L3 between the front wheel axis 33 and the rear wheel axis 35, where the wheelbase L3 is less than or equal to 41.5 inches.
The tandem bicycle can also include a bottom tube member 20, wherein an outer perimeter of the frame 92 is formed by the top 18, the bottom 20, the head 16, and the rear seat 22 tube members. A power transmission can include first and second cranksets 42, 50, where rotation of either one of the first and second cranksets 42, 50 drives the rear wheel 34. The first crankset 42 can be rotatably mounted to an end of a portion of the front seat tube member 22′, and wherein the portion extends outside the outer perimeter. Rotation of either one of the first and second cranksets 42, 50 drives the rear wheel. It should also be understood that either one or both of the first and second cranksets 42, 50 can be replaced with a motor-driven crankset that can be used to drive the rear wheel 34 without a rider pedaling the cranksets 42, 50. In the motor driven version, it may not be necessary (and probably not desired) to have a second crankset incorporated into the tandem bicycle 40. In this confirmation, the rear motor driven crankset 50 would power the tandem bicycle without human interaction, such as pedaling. The motor used to drive the crankset 42 or 50 (or drive the rear wheel 34 directly via a linkage to a sprocket on the rear wheel 34) can be any type of suitable motor for driving the rear wheel 34, such as electric, electro/mechanical, internal combustion, etc.
The front seat tube longitudinal axis 72 can intersect the head tube longitudinal axis 70 at an intersection that is less than 120 inches above a riding surface 8. The front seat tube longitudinal axis 72 can also intersect the head tube longitudinal axis 70 at an intersection that is less than 75 inches above a riding surface 8.
A relative angle A3 between the head tube longitudinal axis 70 and a riding surface 8 can be between 50 degrees and 80 degrees. The relative angle A3 can also be between 55 degrees and 68 degrees.
1Rotation of the front wheel can form a first rotational plane 90 about a rotational axis 33 of the front wheel 32, and with the first rotational plane 90 extending from the rotational axis 33 of the front wheel 32 to an outer diameter of the front wheel 32.
Another embodiment of the tandem bicycle can include a frame 92 suspended between the front and rear wheels 32, 34. The frame can include a top tube member 18, a head tube member 16 positioned at a front end of the frame 92, a front seat tube member 22′, and a rear seat tube member 22, front and rear cranksets 42, 50 can drive the rear wheel, with each one of the front and rear cranksets 42, 50 having an axis of rotation. The front crankset 42 can include left and right pedals 44, where rotation of the left pedal 44 forms a second rotational plane 82, and rotation of the right pedal 44 forms a third rotational plane 84, and where a portion of the first rotational plane 90 is positioned between the second and third rotational planes 82, 84, and the first rotational plane 90 overlaps the second and third rotational planes 82, 84. A perpendicular distance between the second and third rotational planes 82, 84 can determine a maximum diameter of the front wheel 32. Contact between the front wheel 32 and either one of the left and right pedals 44 is avoided when an outer diameter of the front wheel 32 that is less than or equal to the maximum diameter determined by the perpendicular distance between the second and third rotational planes 82, 84.
The tandem bicycle can include a wheelbase L3 that is a horizontal distance L3 between the front wheel axis 33 and the rear wheel axis 35, and a rear crankset distance L13 is a horizontal distance between the axis of the rear crankset 50 and the rear wheel axis 35, where a ratio between the rear crank distance L13 and the wheelbase L3 is between 0.28 and 0.42.
Another embodiment of the tandem bicycle 40 can include front and rear wheels 32, 34, and a frame 92 suspended between the front and rear wheels 32, 34. The frame 92 can include a top tube member 18, a head tube member 16 positioned at a front end of the frame 92, a front seat tube member 22′, and a rear seat tube member 22. The tandem bicycle 40 can also include a handle bar 30 positioned at the front end of the frame 92 and rotatably mounted to the head tube member 16, where the axis 70 of the front seat tube member 22′ intersects the axis 72 of the head tube member 16 at a first intersection, and where the first intersection is less than 120 inches above a riding surface 8. The first intersection could be less than 75 inches above the riding surface 8.
Another embodiment of the tandem bicycle 40 where the front seat 38′ can be mounted to the top tube member 18 (or possibly called a support member 18) by a clamp without a front seat tube member 22′ being utilized. The bicycle 40 can include front and rear wheels 32, 34 with a frame 92 suspended between them that can include a head tube member 16 positioned at a front end of the frame 92, a rear seat tube member 22, and a support member 18 that connects between the head tube member 16 and the rear seat tube member 22. The bicycle 40 can also include a handle bar 30 positioned at the front end of the frame 92 and rotatably mounted to the head tube member 16, where the handle bar 30 is configured to rotate around and outside of a volume B, and the handle bar 30 extends along opposite sides of the volume B (see
The volume B can be defined by a height L5, a width (L10+L11), and a length (L8+L9), with the volume B being positioned above the support member 18, and along the support member 18 between the head tube member 16 and the rear seat tube member 22, with the volume B being centered over a longitudinal axis 74 of the support member 18 and opposite sides of the volume B being parallel to the longitudinal axis 74, with the volume B extending from above the support member 18 by the height L5, and with the volume extending from 2 inches behind the head tube member 16 by the length (L8+L9). The height L5 can be 5 to 24 inches, the width (L10+L11) can be between 2 and 24 inches, and the length (L8+L9) can be 8 and 18 inches. The frame 92 can include a front seat tube member 22′ that extends into the volume B. A longitudinal axis of the head tube member 16 can extend through the volume B. A front seat can be removably mounted to the support member 18 by a clamp at the mount point 94. A cargo mount can also be removably mounted to the support member 18 by a clamp at the mount point 94.
Although various embodiments have been shown and described, the disclosure is not limited to such embodiments and will be understood to include all modifications and variations as would be apparent to one skilled in the art. Therefore, it should be understood that the disclosure is not intended to be limited to the particular forms disclosed; rather, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the appended claims.
The present application is a continuation in-part of U.S. application Ser. No. 14/997,193 filed on 15 Jan. 2016, which is a continuation of U.S. application Ser. No. 14/376,215 filed on 1 Aug. 2014 (now U.S. Pat. No. 9,254,882), which is a national stage filing under 35 USC 371 of International Application No. PCT/US2013/024315, filed on 1 Feb. 2013, which claims priority to U.S. Provisional Application Ser. No. 61/593,718, filed 1 Feb. 2012. The entire disclosures of these prior applications are incorporated herein by this reference.
| Number | Date | Country | |
|---|---|---|---|
| 61593718 | Feb 2012 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14376215 | Aug 2014 | US |
| Child | 14997193 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 14997193 | Jan 2016 | US |
| Child | 15606606 | US |
