WO2004024545A1

WO2004024545A1 - Recumbent bicycle

Info

Publication number: WO2004024545A1
Application number: PCT/CA2002/001393
Authority: WO
Inventors: Christian Roy; Denis Brown
Original assignee: Groupe Procycle Inc.
Priority date: 2002-09-13
Filing date: 2002-09-13
Publication date: 2004-03-25
Also published as: AU2002325735A1

Abstract

A compact and low profile recumbent bicycle is provided with a curved tubular frame configuration. The frame includes a curved top tube having a short front section extending forwardly and upwardly at a relatively large angle and a long straight rear section extending rearwardly and upwardly at a relatively small angle. A front tube is secured to the front end of the top tube for receiving a forks and steering shaft assembly which is supported on a front wheel. A first tubular support assembly is secured to the front and the top tubes for supporting a crank powering assembly. A second tubular support assembly is secured to the first tubular support assembly and the top tube, to be supported on a rear wheel. The second tubular support assembly includes at least one curved tube to form an arced configuration. The frame configuration provides a preferable sitting position to keep the rider in a low profile while facilitating the riding of the bicycle.

Description

RECUMBENT BICYCLE

FIELD OF THE INVENTION

The present invention relates to two-wheel manually powered bicycles in general, and more particularly to a recumbent bicycle.

BACKGROUND OF THE INVENTION

The advantages of recumbent bicycles have been known to those of the bicycle art for many years. It is generally acknowledged that bicycles of a recumbent configuration have a potential for greater riding comfort and speed than conventionally configured bicycles which usually have a relatively high profile. Examples of recumbent bicycles are described in United States

Patent 690,733, issued to Jarvis on January 7, 1902,

United States Patent 4,527,811, issued to DeMoss on

July 9, 1985, United States Patent 4,878,684, issued to

Lemle on November 7, 1989, United States Patent 5,201,538, issued to Mayn on April 13, 1993,

United States Patent 5,284,351, issued to Fleishman on

February 8, 1994, United States Patent 5,509,678, issued to Ullman et al . on April 23, 1996, United States Patent 5,584,494, issued to Krumm on December 17, 1996 and United States Patent 5,853,062, issued to Hulett on December 29, 1998.

However, recumbent bicycles of the prior art are generally awkward to ride and significant practice is required of even experienced riders of conventional bicycles in order to make the transition. As pointed out by Ullman et al . in United States Patent 5,509,678, many of these bicycles have their handle bars for steering mounted on a pivot point beneath the rider, as described in United States Patents 4,527,811 and 4,878,684. Others have handle bars extending rearwardly from steering shafts mounted in a steering head positioned well forward of the rider, with the result that when steering, the rider's hands must sweep through a large radius arc in the manner of a tiller control, rather than rotating about a near central pivot point as is typical of conventional bicycles. This configuration is described in United States Patent 5,853,062. Many recumbent bicycles of the prior art have been provided with adjustable seats which usually move only horizontally. These seats can be adjusted only within a very limited range of leg length of riders, particularly when the bicycles are incorporated with the above described types of non-adjustable steering configurations .

In order to provide sufficient rigidity, recumbent bicycles of the prior art have employed frames composed of numerous frame elements or relatively large sized tubular beams in rectangular cross-section. Thus compromised, is not only esthetic design of recumbent bicycles, making them less attractive from a marketing point of view, but also the compact and low profile

Therefore, there is a need for an esthetic design of a compact and low profile recumbent bicycle which is easy and comfortable to ride and is adapted to allow riders within a large range of sizes and proportions, to ride comfortably and effectively. SUMMARY OF THE INVENTION

One object of the present invention is to provide frame a configuration of a recumbent bicycle with a compact and low profile. Another object of the present invention is to provide a recumbent bicycle which is easy to ride.

It is a further object of the present invention to provide a recumbent bicycle which is adapted to allow riders within a large range of sizes and proportions to ride comfortably and effectively.

In accordance with one aspect of the present invention, a combination of a tubular frame and a saddle assembly secured thereto, is provided for a recumbent bicycle. The combination comprises a curved longitudinal top tube having a front end and a rear end. The top tube includes a front section thereof extending forwardly and upwardly towards the front end at an angle A with respect to a horizontal direction, and a substantially straight rear section thereof extending rearwardly and upwardly toward the rear end, at an angle B with respect to the horizontal direction. Angle A is greater than angle B and the front section of the top tube is shorter than the rear section. A front tube is secured to the front end of the top tube and is adapted for receiving a front forks and steering shaft assembly supported on the front wheel of the bicycle. A first tubular support assembly is positioned below the top tube for supporting a crank power assembly 'of the bicycle. The first tubular support assembly is secured to both the front tube and the top tube. A second tubular support assembly is positioned below the top tube for supporting the frame on a rear wheel of the bicycle. The second tubular support assembly is secured to both the top tube and the first tubular support assembly. The saddle assembly includes a seat and a seat stem secured thereto. The seat stem is telescopically and adjustably secured in the rear section of the top tube .

The front tube preferably extends in a direction substantially perpendicular to the front section of the top tube. The first tubular support assembly preferably comprises a main support tube and a secondary support tube. The main support tube for example, is secured at a front end thereof to the front tube in a spaced relationship with respect to the front section of the top tube. The secondary support for example, is secured at an upper end thereof to the top tube so that a rear end of the main support tube and a lower end of the secondary support tube are joined together to support the crank powering assembly. The secondary tubular support assembly preferably comprises at least one curved tube extending rearwardly and downwardly, to be supported on the rear wheel of the bicycle.

A recumbent bicycle according to another aspect of the present invention comprises a curved longitudinal top tube having a front end and a rear end thereof . The top tube includes a front section thereof extending forwardly and upwardly towards the front end at an angle A with respect to a horizontal direction, and a substantially straight rear section thereof extending rearwardly and upwardly towards a rear end at an angle B with respect to the horizontal direction. Angle A is greater than angle B and the front section of the top tube is shorter than the rear section. A front tube is secured to the front end of the top tube and extends in a direction substantially perpendicular to the front section of the top tube. The bicycle includes a front wheel and a rear wheel as well as a crank powering assembly positioned between the front and rear wheels, for propelling the bicycle by a rider's legs. A front forks and steering shaft assembly is rotatably received through the front tube and the front forks are supported on the front wheel. A first tubular support assembly is secured to both the front tube and the top tube for supporting the crank power assembly. The first tubular support assembly includes a main support tube extending between the front tube and the crank powering assembly, in a spaced relationship with respect to the top tube. A second tubular support assembly is secured to both the top tube and the main support tube, for supporting a load on the rear wheel^' of the bicycle, and includes at least one curved tube extending generally in a longitudinal direction. A saddle assembly is provided with a seat, preferably with a back support, and a seat stem secured thereto. The seat stem extends directly from the seat, is inserted through the rear end of the top tube, and is telescopically secured to the rear section of the top tube in order to provide a low riding position.

In accordance with a further aspect of the present invention, the recumbent bicycle has a seat position defined by a line extending from a joining point of the seat and the back support attached thereto. The line is angled between 30° and 35° with respect to the ground when one of the pedals is pushed to a distal position by the rider sitting on the seat.

The unique frame configuration of the recumbent bicycle in accordance with the present invention, advantageously provides a compact and low profile frame configuration for a recumbent bicycle but is similar to the configuration of a conventional bicycle, thereby resulting in predictable control of the bicycle. Thus, the recumbent bicycle is easy to ride and may be ridden by riders experienced with conventional bicycles without extensive training or practice, and is adjustable to allow riders within a large range of sizes and proportions to ride comfortably and efficiently. The comfortable and efficient riding further results from the fact that the sitting position is slightly higher than the powering assembly, allowing the rider to maintain a low profile for more stability, and to lean on the back support in order to increase the push power while sitting comfortably in a straight position. Furthermore, the frame configuration with curved tubes presents an aesthetically pleasing appearance and makes the recumbent bicycle of the present invention more attractive from a marketing point of view.

Other advantages and features of the present invention will be better understood with reference to preferred embodiments of the present invention described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

Having thus generally described the nature of the present invention, reference will now be made to the accompanying drawings, showing by way of illustration the preferred embodiments thereof, in which:

Fig 1 is a side elevational view of a recumbent bicycle according to one preferred embodiment of the present invention;

Fig. 2 is a top plan view of the recumbent bicycle of Fig. 1, positioned in a opposed position;

Fig. 3 is an enlarged cross-sectional view taken along line 3-3 in Fig. 1 showing an alternative telescopic connection of the seat stem within the top tube of the frame;

Fig. 4 is a side elevational view of a recumbent bicycle according to another embodiment of the present invention; Fig. 5 is a side elevational view of a recumbent bicycle according to a further embodiment of the present invention; and

Fig. 6 is a schematic illustration showing the seat position for comfortable and efficient riding.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to Figs. 1 and 2, a recumbent bicycle, according to a preferred embodiment of the present invention and generally indicated by numeral 10, has a tubular frame 12. The tubular frame 12 generally includes a curved longitudinal top tube 14, a front tube 16, a first tubular support assembly 18 and a second tubular support assembly 20.

The curved top tube 14 has a circular or elliptical cross-section and is relatively large compared to the cross-section of other tubes in the frame 12. The top tube 14 is smoothly bent such that a front section 22 extends forwardly and upwardly towards the front end at an angle A with respect to a horizontal direction when the recumbent bicycle 10 is on a horizontal ground 24, and a rear section 26 which is substantially straight extends rearwardly and upwardly towards the rear end thereof at an angle B with respect to the horizontal direction. Angle A is greater than angle B, and the front section 22 is much shorter than the rear section 26. In this particular embodiment, angle A is about 35 degrees and angle B is about 14 degrees. The front tube 16 is secured to the front end of the top tube 14 by for example, welding, and preferably extends in a direction substantially perpendicular to the front section 22 of the top tube 14. The front tube 16 has a circular cross-section which is also relatively large for receiving a steering shaft 28 extending downwardly therethrough, to be affixed to a front forks member 30. The front forks member 30 is supported on a front wheel 32 and the top section of the steering shaft 28 has a tubular extension member 34 telescopically connected to the top section of the steering shaft 28. The tubular extension member 34 can be adjustably projected upwardly and locked at a desired position to rotate together with the steering shaft 28, which will be further discussed hereinafter with reference to Fig. 3. A top bar 36 is attached to the top end of the tubular extension member 34 and extends perpendicularly with respect to the steering shaft 28. Thus, manipulation of the top bar 36 to rotate the steering shaft 28 will turn the front wheel 32. The forks and steering shaft assembly is similar to that of conventional bicycles and will not be further described.

The first tubular support assembly 18 includes a main support tube 38 which is at a front end thereof affixed to the front tube 16 for example, by welding in a spaced relationship with respect to the front section 22 of the top tube 14. The main support tube 38 is substantially perpendicular with respect to the front tube 16 and extends downwardly and rearwardly therefrom. A secondary support tube 40 is secured at an upper end thereof to the top tube 14 by for example, welding at a place positioned in the rear section 26 but close to the bend point thereof . A rear end of the main support tube 38 and a lower end of the secondary support tube 40 are joined together by for example, welding to support a crank powering assembly 42. The crank powering assembly 42 usually includes crank members and a sprocket and chain assembly which are both well known in the art and will not be further described. The main support tube 38 has a circular or elliptical cross-section which is relatively large in order to provide adequate solidity to the frame structure. The secondary support tube 40 has a circular or elliptical cross-section which is relatively small .

The second support assembly 20 includes a chain stay consisting of a pair of curved tubes 44. The pair of curved tubes 44 are joined together at their front ends and secured to a middle portion of the main support tube 38 by, for example welding. The curved tubes 44 extend divergently, rearwardly and downwardly towards the rear end which is supported on a rear wheel 46 of the recumbent bicycle 10. The rear wheel 46 is flanked by the rear section of the pair of curved tubes 44. A chain guard plate 47 is attached to one of the curved tubes 44 at a right-hand side of the recumbent bicycle 10 by for example, bolts or screws 48 in order to protect the rider's pants from contact with the chain. An idle sprocket (not indicated) is mounted on a bracket (not indicated) extending downwardly from one of the curved tubes 44. A middle portion of the chain suspends on the idle sprocket to prevent the middle portion of the chain from sagging, which is advantageous for a low profile bicycle.

A seat stay comprises a pair of tubes 50. The pair of tubes 50 are joined together at their upper ends and secured to the rear section 26 of the top tube 14 by, for example welding. The tubes 50 extend divergently, rearwardly and downwardly toward their rear ends. Each tube 50 is joined at its lower end to the corresponding rear end of one of the tubes 44, and both tubes 50 are supported on the rear wheel 46. The pair of tubes 50 are both substantially straight and are only bent downwardly at their lower ends for joining with the rear ends of the corresponding curved tubes 44. The cross-section of the tubes 44, 50 have a circular or elliptical cross-section which is relatively smaller in comparison with the cross-sections of other tubes of the frame 12. The first tubular support assembly 18 and the second tubular support assembly 20 together with the top tube 14 and the front tube 16 in combination, constitute a closed frame configuration providing an adequate solidity to the frame 12 of the recumbent bicycle 10. Meanwhile, the thin curved tubes 44 which have a relatively long span and are reinforced by the thin tubes 50, constitute an arced configuration.

A saddle assembly 52 is adjustably attached to the frame 12. The saddle assembly 52 includes a seat 53 and a seat stem 54 secured thereto. A back support 56 is attached to a rear end of the seat 53. The seat 53 and the back support 56 can be various types which are well known in the art and will not be further describe ed herein. The seat stem 54 is inserted through the rear end of the top tube 14 and is telescopically received therein. The seat stem 54 is secured directly to the base of the seat 53 and extends forwardly and downwardly at an angle substantially equal to angle B, with respect to the longitudinal axis of the seat, which is usually parallel to the horizontal ground 24. The seat stem 54 can be adjusted along the extension line of the rear section 26 of the top tube 14 in order to allow a large range of sizes and proportions to a rider to ride comfortably and effectively.

A lock device is provided to lock the seat stem 54 in the selected position with respect to the frame 12. The lock device can be a conventional one employing a bolt 58 which can adjust the width of a small longitudinal groove 59 (see Fig. 2) at the rear end of the top tube 14 in order to clamp the rear section 26 thereof around the seat stem 54 when locking is required. An alternative arrangement of the locking device is illustrated in Fig. 3. In this arrangement the seat stem 54 is bent radially and inwardly to form an axially extending keyway 60, so that an adjustment screw 62 threadedly attached to the rear section 26 of the top tube 14 is adapted to engage in the keyway 60 in order to lock the seat stem 54 in the selected position.

The alternative arrangement of the locking device illustrated in Fig. 3 can also be used in the telescoping connection between the steering shaft 28 and the tubular extension member 34 of Fig. 1. In such a case, the steering shaft 28 is bent radially and inwardly to form the axially extending keyway and is inserted into the tubular extension member, and then, is locked in position by the adjustment screw. The configuration of the respective steering shaft 28 and the extension member 34 could be arranged in the reverse order if the tubular extension member 34 is telescopingly received in the steering shaft 28.

The seat 53 directly mounted on the inclined seat stem 54 without any vertical extending support, advantageously lowers the riding position. The smaller angle B, for example 14 degrees in this embodiment, ensures that the seat 53 can be adjusted rearwardly and upwardly to accommodate a longer leg length of a rider, while maintaining a relatively low riding position. The relatively large angle A, for example 35 degrees in this embodiment, ensures that the steering shaft 28 with extension 34, inclines away from a vertical position and extends upwardly, rearwardly and adequately towards the rider over a relatively long span between the front tube 16 and the seat 53, even when the seat is adjusted in a relatively rearward position.

Fig. 4 illustrates a recumbent bicycle 110 according to another embodiment of the present invention. The recumbent bicycle 110 includes a frame 112 which will be further described hereinafter, and includes attached parts, such as wheels, crank powering assembly, steering assembly and saddle assembly, all of which are similar to those of recumbent bicycle 10 in Fig. 1 and are indicated by the respective similar numerals, and will not be redundantly described.

The frame 112, similar to the frame 12 of the recumbent bicycle 10 in Fig. 1, comprises a curved top tube 114, a front tube 16, a first tubular support assembly 18 and a second tubular support assembly 120. The front tube 16 and the first tubular support assembly 18 are similar to those of the recumbent bicycle 10 in Fig. 1, indicated by the respective similar numerals, and will not be redundantly described herein. The difference between the frames 112 and 12 of the recumbent bicycle 110 and the recumbent bicycle 10 lies in the second tubular support assembly 120 and in the top tube 114. The second tubular support tube 120 includes a chain stay consisting of a pair of curved, relatively thin tubes 144 which are longer than the corresponding thin curved tubes 44 of the recumbent bicycle 10 of Fig. 1. The pair of curved tubes 144 are joined together at their front ends and attached by, for example welding, to the main support tube 38 close to its front end rather than at a middle section thereof, as in the embodiment illustrated in Fig. 1. The pair of curved tubes 144 extend divergently, rearwardly and downwardly towards their rear ends over a relatively longer span than that of the curved tubes 44 in Fig. 1. The curved tubes 144 are spaced apart at their rear sections for receiving the rear wheel 46 positioned therebetween and are supported at their rear ends on the rear wheel 46. The second tubular support assembly 120 also includes the idle sprocket (not indicated) and the chain guard plate 47 attached to one of the curved tube^'s 144 at the right-hand side of the recumbent bicycle 110.

The top tube 114 is similar to the top tube 14 of the recumbent bicycle 10 shown in Fig. 1, but a rear section 126 thereof is slightly shorter than the rear section 26 of the top tube 14 in Fig. 1. Thus, the seat stay consists of a pair of thin tubes 150 extending between the- rear end of the top tube 114 and the rear ends of the curved tubes 144. The tubes 150 are longer than the corresponding tubes 50 of the recumbent bicycle 10 in Fig. 1, and are- joined together at their upper ends which are secured by, for example welding, to the rear end of the top tube 114. The tubes 150 extend divergently, rearwardly and downwardly for accommodating the rear wheel 46 positioned therebetween, and are secured together at their lower ends to the rear ends of the corresponding curved tubes 144. The joined ends of the curved tubes 144 and 150 are supported on the rear wheel 46. Similar to the tubes 50 of Fig. 1, the tubes 150 are bent downwardly at a point close to their lower ends, however unlike tubes 50, tubes 150 are also slightly curved downwardly along the majority of their length.

In such an arrangement the arced configuration provided by the curved thin tubes 144 has a longer span.

^■ The angle between the respective curved tubes 144 and curved tubes 150 is smaller than the angle between the respective curved tubes 44 and the substantially straight tubes 50. Fig. 5 illustrates a recumbent bicycle 210 according to a further embodiment of the present invention. The recumbent bicycle 210 includes a frame 212, and the parts attached thereto, such as the wheels, crank powering assembly, steering assembly and saddle assembly all of which are similar to those of the recumbent bicycle 10 of Fig. 1, and are indicated by the respective similar numerals, and will not therefore be redundantly described. The frame 212 includes a top tube 14 and a front tube 16 which are similar to the parts indicated by the respective similar numerals in Fig. 1 and will not be redundantly described, and further includes a first tubular support assembly 218 and a second tubular support assembly 220.

The first tubular support assembly 218 includes a curved main support tube 238 secured by for example, welding at a front end thereof to the front tube 16 in a spaced relationship with respect to the front section 22 of the top tube 14. A secondary support tube 40 which is similar to that indicated by the similar numeral in Fig. 1, is secured by for example, welding at an upper end thereof, to the top tube 14. The rear end of the curved main support tube 238 and a lower end of the secondary support tube 40 are joined together to support the crank powering assembly 42.

The second tubular support assembly 220 includes a chain stay consisting of a pair of curved tubes 244 extending rearwardly and upwardly from the joined ends of the curved main support tube 238 and the secondary support tube 40, thereby forming a smooth extension of the curved main support tube 238 when being viewed from a side of the recumbent bicycle 210. The rear ends of the curved tubes 244 rather than being supported on the rear wheel 46, are secured by for example, welding to the respective curved tubes 250 which function as the seat stay. The pair of curved tubes 250 are joined together at their upper ends and are secured by for example, welding, to a middle region of the top tube 14 immediately behind the bent section between the front and rear sections 22 and 26, rather than to the rear end thereof, as shown in recumbent bicycle 10 of Fig. 1. The curved tubes 250 extend divergently, downwardly and rearwardly from the top tube 14 towards their lower ends for accommodating the rear wheel 46 positioned therebetween, and are supported at their lower ends on the rear wheel 46. The curved tubes 244 are secured at their rear ends by for example, welding to the respective curved tubes 250 at a position which is preferably located about one third of the way along the length of the curved tubes 250 from the lower ends thereof, rather than being secured to the lower ends of the curved tubes 250.

Thus, the curved tubes 250 in cooperation with a section of the top tube 14 provide the frame 212 with an arced configuration while the curved tubes 244 reinforce this arced configuration. In this arrangement, the cross-sections of the curved tubes 250 preferably are of medium size compared with the relatively thick top tube 14 and the relatively thin curved tubes 244. The chain guard plate 47 is also provided along with the second tubular support assembly 220, and is attached to one of the curved tubes 250 of the seat stay but not to the chain stay of the curved tube 244, like those of the previously described embodiments. The idle sprocket (not indicated) and its support bracket (not indicated) are supported on one of the curved tubes 244. The recumbent bicycle 210 with those curved tubes of the first and second tubular support assemblies also presents an alternative aesthetically pleasing appearance.

The embodiments described with reference to the drawings are only examples of the present invention. Other alternative arrangements of the first and second tubular support assembly may be possible provided that the seat position with respect to the crank assembly is restricted within a predetermined area, as illustrated in Fig. 6. Letter A indicates the rotary center of a pedal of the crank powering assembly and the letter B indicates the center of the crank powering assembly. The seat position of the rider is referenced by a point S which is a joining point of the seat plane and the back support, and point H indicates a pivotal center of the rider's waist . A preferable seat position is defined by the straight line SA. The line SA should be angled between 30° and 35° with respect to the ground indicated by letter G on which the bicycle is ridden. The straight line HA extends through point B such that the rider sitting on the seat and leaning on the back support can stretch his or her one of the legs to push this pedal to its most distal position. The hatched area SRP, as an example, shows the sitting position is adjustable from a height of about 700 mm with respect to the ground G, to a height of about 750 mm within the angled range of 30° to 35°. This adjustment is achieved in the embodiments of Figs. 1, 4 and 5 by extending the saddle assembly 52 rearwardly and upwardly along the top tube 14. Corresponding to the adjustment of the seat position from S to S', the pivotal center of the rider's waist moves from H to H', which is an option for longer legged riders. It is noted that in the illustration, straight line H'A is slightly deviated from point B. In order to correct this inadequacy of the illustration, point A should be moved slightly. However, this inadequacy of the illustration can be ignored in contrast to the length of line S'A. This preferable sitting position provides the low riding profile for stability while facilitating the riding of the recumbent bicycle.

Modifications and improvements to the above described embodiments of the present invention may become apparent to those skilled in the art. The forgoing description is intended to be exemplary rather than limiting. The scope of the invention is therefore intended to be limited only by the scope of the appended claims.

Claims

I /WE CLAIM :

A combination of a tubular frame and a saddle secured thereto for a compact and low profile recumbent bicycle comprising: a curved longitudinal top tube, having a front end and a rear end, the top . tube including a front section thereof extending forwardly and upwardly towards the front end at an angle A with respect to a horizontal direction and a substantially straight rear section thereof extending rearwardly and upwardly towards the rear end at an angle B with respect to the horizontal direction, wherein A is greater than B and the front section is shorter than the rear section; a front tube for receiving a front forks and steering shaft assembly supported on a front wheel of the bicycle, the front tube being secured to the front end of the top tube; a first tubular support assembly positioned below the top tube for supporting a crank powering assembly of the bicycle, the first tubular support assembly being secured to both the front tube and the top tube; a second tubular support assembly positioned below the top tube for supporting the frame on a rear wheel of the bicycle, the second tubular support assembly being secured to both the top tube and the first tubular support assembly; and the saddle assembly including a seat and a seat stem secured thereto, the seat stem being telescopically and adjustably secured in the rear section of the top tube.

2. A combination as claimed in claim 1 wherein the front tube extends in a direction substantially perpendicular to the front section of the top tube.

3. The combination as claimed in claim 1 wherein the first tubular support assembly comprises a main support tube and secondary support tube, the main support tube being secured at a front end thereof to the front tube in a spaced relationship with respect to the front section of the top tube, the secondary support tube being secured at an upper end thereof to the top tube, a rear end of the main support tube and a lower end of the secondary support tube being joined together to support the crank powering assembly.

4. The combination as claimed in claim 3 wherein the main support tube extends substantially perpendicular with respect to the front tube.

5. The combination as claimed in claim 3 wherein the main support tube is curved.

6. The combination as claimed in claim 5 wherein the second tubular support assembly comprises a curved tube extending rearwardly and upwardly from the joined ends of the curved main support tube and the secondary support tube and forming a smooth extension of the curved main support tube when being viewed from a side thereof.

7. The combination as claimed in claim 1 wherein the second tubular support assembly comprises at least one curved tube extending rearwardly and downwardly to be supported on the rear wheel of the bicycle.

8. The combination as claimed in claim 7 wherein the at least one curved tube is secured at a front end thereof to the top tube .

9. The combination as claimed in claim 8 wherein the second tubular support assembly further comprises an additional curved tube secured at a front end thereof to the first support assembly and extending rearwardly and upwardly to be joined with the at least one curved tube.

10. The combination as claimed in claim 7 wherein the at least one curved tube is secured at a front end thereof to the first tubular support assembly.

11. The combination as claimed in claim 10 wherein the second tubular support assembly further comprises a rear support tube extending between the rear end of the top tube and a rear end of the at least one curved tube .

12. The combination as claimed in claim 1 wherein the seat stem is secured directly to a base of the seat in order to provide a low riding position.

13. The combination as claimed in claim 12 wherein the seat stem extending forwardly and downwardly at an angle substantially equal to the angle B with respect to a longitudinal axis of the seat .

14. A combination as claimed in claim 12 wherein the top tube comprises a circular cross-section and the seat stem comprises a corresponding cross-section with an inwardly bent and axially extending keyway to permit an adjustment screw operatively attached to the top tube to engage therein.

15. A recumbent bicycle comprising: a curved longitudinal top tube having a front end and a rear end thereof, the top tube including a front section thereof extending forwardly and upwardly towards the front end at an angle A with respect to a horizontal direction and a substantially straight rear section thereof extending rearwardly and upwardly towards the rear end at an angle B with respect to the horizontal direction, wherein A is greater than B and the front section is shorter than the rear section; a front tube secured to the front end of the top tube and extending in a direction substantially perpendicular to the front section of the top tube; a front wheel and a rear wheel ; a crank powering assembly positioned between the front and rear wheels for propelling the bicycle by a rider's legs; a front forks and steering shaft assembly rotatably received through the front tube and supported on the front wheel,; a first tubular support assembly for supporting the crank powering assembly, the first tubular support assembly being secured to both the front tube and the top tube and including a main support tube extending between the front tube and the crank powering assembly in a spaced relationship with respect to the top tube ; a second tubular support assembly for supporting a load on the rear wheel of the bicycle, the second tubular support assembly being secured to both the top tube and the main support tube, and including at least a curved tube extending generally in a longitudinal direction; and a saddle assembly including a seat and a seat stem secured thereto, the seat stem extending directly from the seat and being inserted through the rear end of the top tube and telescopically secured to the rear section of the top tube in order to provide a low riding position.

16. A bicycle as claimed in claim 15 wherein the steering shaft comprises a telescopic configuration such that a front bar attached to a top end of the steering shaft can be adjusted to project upwardly and rearwardly.

17. A bicycle as claimed in claim 15 wherein the top tube comprises a circular cross-section and the seat stem comprises a corresponding cross-section with an inwardly bent and axially extending keyway to permit an adjustment screw operatively attached to the top tube to engage therein in order to lock the seat at a selection position on the bicycle.

18. A bicycle as claimed in claim 15 wherein the saddle further comprises a back support attached to a rear end of the seat .

19. A bicycle as claimed in claim 16 wherein the telescopic configuration of the steering shaft comprises a first tubular element and a second tubular element, the first tubular element being slidably received in the second tubular member and including an inwardly bent and axially extending keyway thereon, for engaging an adjustment screw operatively attached to the second tubular member.

20. A recumbent bicycle comprising: a frame; a front wheel and a rear wheel ; a steering assembly; a crank powering assembly including a pair of pedals, each being rotatable about both a center thereof and a center of the crank powering assembly, the crank power assembly being operatively attached to the frame for propelling the bicycle by a rider's legs; and seat with a back support attached thereto, forming a joining point thereof, the seat being mounted to the frame behind and above the crank powering assembly in a position defined by a straight line extending from the joining point to the center of one of the pedals, which line is angled between 30° and 35° with respect to the ground when the one of the pedals is pushed by the rider to a most distal position.