WO2000024630A1

WO2000024630A1 - Human powered thruster system with a sliding ratio drive transmission

Info

Publication number: WO2000024630A1
Application number: PCT/US1999/025076
Authority: WO
Original assignee: Benoit, Michael, J.
Priority date: 1998-10-26
Filing date: 1999-10-25
Publication date: 2000-05-04
Also published as: AU1599000A

Abstract

A human powered vehicle or drive train having a pair of levers (18, 20) pivotally mounted to a frame (12), an advancing cam mechanism and a sliding ratio drive. The advancing cam mechanism, mounted at one end of each lever arm, has a fixed gear and a free floating gear joined with an elongate cam (56). The cam is coupled to an opposing cam on a unidirectional clutch (72, 74) mounted to a drive shaft by a chain or cable. Oscillation of the lever draws the cable through the clutch rotating the drive shaft. The drive shaft preferably turns a sliding ratio drive transmission but may directly turn a sprocket, gear or drive wheel. The sliding ratio drive transmission uses a vertical revolving disk (100) which engages and rotates a torque transfer wheel with an output axle perpendicular to the revolving disk. The axle rotates at a speed set at a ratio to the angular velocity of the disk as determined by the radial distance of the position of the wheel on the disk. The position of the wheel on the face of the disk can be changed under load due to free spinning sections of the wheel that engage the disk. Foot pedals are mounted to the levers and can be actuated alternately, in unison or singly to propel the vehicle.

Description

TITLE OF THE INVENTION

HUMAN POWERED THRUSTER SYSTEM WITH A

SLIDING RATIO DRIVE TRANSMISSION

CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority from U.S. Provisional Application serial number 60/105,706 filed on October 26, 1998 which is incorporated herein by reference and from U.S. Provisional Application serial number 60/137,005 filed on June 1 , 1999 which is incorporated herein by reference.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

OR DEVELOPMENT Not Applicable

REFERENCE TO A MICROFICHE APPENDIX

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention This invention pertains generally to human powered drive trains for vehicles or stationary applications such as pumping or exercise devices, and more particularly to an improved drive system having an advancing cam mechanism and a sliding ratio drive transmission.

2. Description of the Background Art A bicycle is a commonly used human powered vehicle for exercise, competition and transportation of human beings. The typical bicycle has a drive mechanism consisting of a circular sprocket with radially positioned pedals; one or more drive sprockets at the rear axle, with the two sprockets being connected with an endless chain. Rotation of the pedal sprocket by the rider produces rotation of the drive sprocket at the rear wheel and motion of the bicycle.

The mechanical advantage or torque produced at the rear axle of a conventional bicycle is dependent upon the gearing ratio between the pedal sprocket and the drive sprocket at the rear axle. The available torque produced at the drive sprocket can be varied using different combinations of pedal and drive sprockets having varying diameters. Accordingly, the overall speed and climbing capabilities of the bicycle, as a vehicle, are dependent upon gearing ratios between the pedal sprocket and drive sprocket at the rear wheel. Ultimately, the duration of the ride, or the total torque produced by the system over time, is dependent upon the gearing ratios as well as the fitness of the individual rider.

Means for shifting the chain between sprockets of different diameters are well known in the art. These systems allow the rider to provide, incrementally, torque to the rear axle for climbing an incline as well as accelerating on a level surface.

While this type of drive mechanism has been a useful means for converting human motion to useable torque, it is not without limitations. For example, these shifting mechanisms are not able to function under high constant loads making them unsuitable for certain applications. These mechanisms are also comparatively complex, lack durability and are prone to failure with long term use. Another deficiency in the prior art rotary drive system is that the torque ratios and load capabilities are limited to a certain range as a result of the physical characteristics of humans. Accordingly, the prior art system is not suitable for tasks such as pumping where significant torque is required since the apparatus has a constant heavy load

A further deficiency of the prior art is that the rotary pedal system does not maximize the torque producing forces produced by the rider on the pedals. As a consequence, the system is energy inefficient and limits the total amount of work that can be performed by the operator. Another drive system known in the art typically utilizes a lever arm to drive a sprocket on the rear wheel of the bicycle. While the use of a lever arm increases the mechanical advantage, these devices have the disadvantage of a complex arrangement of cables or chains. The torque that is normally produced in these prior art systems is not variable and is limited to that torque produced at a single sprocket on the rear wheel.

Therefore, there is a need for a need for a human powered drive train that efficiently generates torque to operate a pump or propel a vehicle. The present invention satisfies that need, as well as others, and overcomes deficiencies found in prior human powered vehicle designs.

BRIEF SUMMARY OF THE INVENTION The present invention generally comprises a human powered vehicle with an improved thruster-type drive system. By way of example, and not of limitation, in accordance with one aspect of the invention, a human powered propulsion system and vehicle are provided with a pair of foot actuated levers, each having an advancing cam mechanism, and sliding ratio drive transmission. The thruster system efficiently converts the vertical motion of the thruster arms (levers) to rotational motion at the wheel with a significant mechanical advantage. The system transfers torque to a rear wheel at a much higher rate than is achieved by conventional pedal powered bicycles or machines. Accordingly, the energy needed to propel the vehicle or operate a machine is greatly reduced.

The thruster drive system generally comprises two primary elements; the lever with an advancing cam mechanism (ACM) and the sliding ratio drive (SRD) transmission. In the ACM element, one or more levers are pivotally mounted to a drive housing or frame. A footpad is attached to one end of the lever and the advancing cam mechanism is on the other. The advancing cam mechanism comprises a fixed lower gear, a free floating cam gear, and an elongate advancing roller cam. The fixed lower gear has a plurality of circumferentially spaced axial teeth and is mounted to the housing. The free floating gear is rotatably mounted to the lever arm with an advancing roller cam secured to the free floating gear and rotates in unison with the floating gear. The free floating gear has circumferentially spaced teeth which engage and interlock with the teeth of the fixed lower gear. A cable or chain is affixed to the advancing roller cam and extends to an opposing cam on a unidirectional roller clutch on an input drive shaft. The input shaft is connected to the sliding ratio drive transmission or, alternatively, to a drive sprocket, drive gear or clutch.

During each cycle, the footpad and thruster arm are forced downwardly by the exertion and weight of the rider. At the same time the free floating gear rotates about its axis and traverses the circumference of the fixed lower gear. Rotation of the free floating gear causes the elongate advancing roller cam to rise. Rotation of the cam causes the chain to advance and the raising of the cam effectively increases the amount of "throw" or length of chain drawn. Not only does the advancing cam increase the amount of throw, it increases the throw at the end of the stroke. This allows for a high starting torque as the cam is down and the effective distance from the fulcrum is shortest at the beginning of the stroke. As the vehicle or device is in motion, the available torque reduces and the effective distance from the fulcrum increases as the throw increases.

The opposing elongate cam on the unidirectional roller clutches rotating the input drive shaft also increase the mechanical advantage of the system. The amount of force necessary to rotate the drive shaft is less at the beginning of the stroke because the cam is fully extended.

Normally the levers with the advancing cam mechanism come in pairs which oscillate. The lever arms may be positioned horizontally, vertically or at any suitable angle to allow the operator to exert force thereon. The levers may also be positioned to be actuated by the hands either parallel or in a rowing configuration. One frame design allows the rider to stand while applying vertical force on the levers allowing for good vertical spinal alignment while in motion.

The force provided by the chain drawn by the iever causes a transmission drive shaft to rotate in the sliding ratio drive transmission. Each lever can rotate the transmission input drive shaft independently of the other. Consequently, both levers may be actuated simultaneously as well as alternately to drive the transmission output shaft and provide motion to the vehicle.

The sliding ratio drive element is a transmission, or ratio change device whereby power is applied to a drive gear (or the input shaft directly) which turns a rotatable drive disk, or platten, which then powers a main output shaft. The sliding ratio drive allows for rotational speed or torque to be variably converted from an input to an output.

The drive operates by transferring power from the spinning disk to a torque transfer wheel that is configured to engage the disk. The transfer wheel, once engaged, is set to rotate on an axle on which it is slidably engaged. The axle then rotates at a rotational speed that is set at a ratio to the disk's angular velocity as determined by the radial distance of its positioning on the disk. The axle of the transfer wheel is the output shaft or connected directly to the rear wheel. The torque transfer wheel can move across the face of the disk under load due to free spinning sections of the transfer wheel which engage the disk. Power can in fact be transferred in either direction with the invention while the speed ratios from input to output can be varied continuously.

It can be seen by one skilled in the art that the thruster arm with the advancing cam mechanism can be used alone or in combination with the sliding ratio drive to provide human power for many applications. The sliding ratio drive transmission may also be used with a prime mover such as an electric motor.

It is an object of the invention to provide a novel means of propulsion for human powered vehicles utilizing oscillating lever arms with advancing cam mechanisms to generate rotational motion.

Another object of the invention is to provide a human powered apparatus, vehicle or stationary exercise machine that maximizes the torque produced by the motion of the operator.

Yet another object of the invention is to provide a drive train that can be used to efficiently propel a vehicle, operate a pump, or other apparatus under constant load.

A further object of the invention is to provide a power conversion device that allows the output speed to be varied in relation to the input speed.

Another object of the invention is to provide a transmission that can be readily shifted while under load.

Yet another object of the invention is to provide a transmission that is simple to fabricate.

Another object of the invention is to provide a transmission wherein the input and output can be decoupled in a manner similar to that of a clutch. Further objects and advantages of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing preferred embodiments of the invention without placing limitations thereon.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be more fully understood by reference to the following drawings which are for illustrative purposes only and where like reference numbers denote like parts:

FIG. 1 depicts a side view of the human powered vehicle with the thruster drive system according to the invention. The advancing cam mechanism and sliding ratio drive of the thruster drive system are highlighted within the box made of dashed lines.

FIG. 2 is a perspective view of the torque translation portion of the thruster drive system according to the present invention with a pair of thruster arms with the advancing cam mechanisms operably connected to corresponding clutches on a drive shaft. Springs which reset the cables after each stroke are shown.

FIG. 3 shows the relationship between the advancing cam mechanism and the roller clutch with a cam on the drive shaft. The relative positions of the parts at the end of the stroke are set forth in dashed lines. Swiveled footholds on the thruster arms are also shown.

FIG. 4 shows an alternative embodiment of the torque translation portion of the thruster drive system having a unidirectional roller clutch without a cam surface in accordance with the present invention. FIG. 5 schematically shows a multi staged gearing with multiple mid stage sprockets in accordance with the present invention.

FIG. 6 schematically shows a single stage configuration of the present invention with multiple input drive sprockets.

FIG. 7 schematically shows a single stage configuration with multiple output drive sprockets.

FIG. 8 schematically shows the input shaft turning spiral bevel gears and output drive shaft in accordance with the present invention.

FIG. 9 is a side view of the advancing cam mechanism with the sliding ratio drive transmission. FIG. 10 is a top view of the preferred embodiment of the present invention depicting the torque translation sections with the advancing cam mechanism and sliding ratio drive.

FIG. 1 1 is a perspective side view of the sliding ratio drive mechanism showing the drive disk, servo and output shaft. FIG. 12 is a perspective side view of the sliding drive mechanism showing unidirectional clutches, input drive shaft and disk tension member in phantom lines. The wheel guide, transfer wheel and servo are also shown. FIG. 13 is a top view of the sliding ratio drive.

FIG. 14 is a front view of one embodiment of the drive disk with rods, springs and rings to improve the flywheel characteristics of the disk in accordance with the present invention shown in phantom. FIG. 15 Is a top view of the embodiment shown in FIG. 14.

FIG. 16 is a front view of the sliding ratio drive transmission of the present invention.

FIG. 17 is a side view of one embodiment of the torque transfer wheel showing the engagement of the wheel on the drive disk. Sockets and rotating tops in the transfer wheel are shown in phantom lines.

FIG. 18 shows a side view of the torque transfer wheel showing an opposing configuration of the rotating tops and also the spline insert.

FIG. 19 is a top view of the torque transfer wheel.

FIG. 20 depicts and alternative embodiment of the input mechanism for the sliding ratio drive transmission where rotation of the drive disk is accomplished by conventional bicycle type pedals.

FIG. 21 is a top view of the embodiment depicted in FIG. 20.

DETAILED DESCRIPTION OF THE INVENTION Referring more specifically to the drawings, for illustrative purposes the present invention is embodied in the apparatus generally shown in FIG. 1 through FIG. 19. It will be appreciated that the apparatus may vary as to configuration and as to details of the parts without departing from the basic concepts as disclosed herein. FIG. 1 shows a side view of the human powered vehicle 10 having a thruster drive system with an advancing cam mechanism (ACM) and Sliding Ratio Drive (SRD). The advancing cam mechanism and sliding ratio drive of the thruster drive system is encompassed by the box made of dashed lines shown in FIG. 1. Generally, the human powered vehicle 10 comprises a frame 12, at least one drive wheel 14 which is driven by the thruster drive system and a means for steering the vehicle 16. The thruster drive system is generally composed of a torque translating section and a transmission that rotates drive wheel 14 or alternatively a drive shaft. Referring now to Fig. 2, the torque translating section of the thruster drive mechanism includes at least one, but preferably two thruster arms 18 and 20. The right and left thruster arms 18 and 20 have right and left footholds 22 and 24 located at one end. On the opposite end of each of the thruster arms is mounted an advancing cam tower and tubular tower support. Right and left Cam towers 26 and 28 are mounted on right and left tubular tower supports 30 and 32 which are coupled to right and left thruster arms 18 and 20 respectively.

A thruster support axle 34 aligns and supports the thruster arms 18 and 20 and tower supports 30 and 32. Support axle 34 is enclosed within tower supports 30 and 32. Thruster arms 18 and 20 and tower supports 30 and 32 pivot about support axle 34 and the axle remains stationary.

Thruster arms 18 and 20, tower supports 30 and 32 and cam towers 26 and 28 are pivotally mounted to frame 12 or alternatively, to a drive housing, through bearings 36 and 38. The bearings allow each thruster arm and cam tower to freely pivot about the thruster support axle 34 during each stroke.

Right and left free spinning cam advancing gears 40 and 42 are secured to cam towers 26 and 28 by bolts or pinions 44 and 46. Advancing gears 40 and 42 can rotate around pinions 44 and 46. The periphery of cam advancing gears 40 and 42 have grooves or teeth 48 which intermesh and engage corresponding teeth 50 on the periphery of right and left fixed gears 52 and 54. The radius of the cam advancing gears 40 and 42 is smaller that the radius of the lower fixed gears 52 and 54.

Securely mounted to each cam advancing gear is an elongate cam 56 and 58. Rotation of advancing gears 40 and 42 will result in movement of right and left cams 56 and 58.

A chain or cable 60 is attached to cam 56 on one end and to a spring 62 on the other . Likewise, cable or chain 64 is attached to cam 58 on one end and to spring 66and cam 58 on the other end. It is preferred that springs 62 and 66 are connected by a cable 68 which is positioned around a pulley 70. The spring and pulley arrangement provides tension on cables 60 and 64 and returns the cable to its starting position after the end of the stroke.

Cables or chains 60 and 64 engage right and left roller clutches 72 and 74. It is preferred that roller clutches 72 and 74 have elongate right and left arcuate cams 76 and 78. In addition, the shape and dimensions of the advancing cams 56 and 58 and the clutch cams 76 and 78 can be varied depending on the torque requirements.

Clutches 72 and 74 are preferably strong, long lasting locking bearing clutches which are attached to drive shaft 80 and provide continuous rotational motion to drive shaft 80 when drawn by cables 60 and 64. Thus, the oscillating motion of the thruster arms 18 and 20 is converted to rotational motion of drive shaft 80. Furthermore, each thruster arm can deliver torque to the drive shaft 80 independent of the other thruster arm. Consequently, thruster arms 18 and 20 can be actuated simultaneously, alternately or singly to drive the drive shaft 80. The capability and efficiency of the mechanism is dependent, in part, upon the length of cables 60 and 64 drawn through clutches 72 and 74 during a given stroke. This is termed the throw of the stroke. The advancing cam mechanism of the present invention maximizes the throw per stroke while maintaining a compact configuration, in addition, the mechanical advantage of the apparatus is maximized at the beginning of the stroke to overcome higher force requirements to initiate drive shaft rotation. As the rotational speed of drive shaft 80 increases, the torque produced by the thruster arm decreases while the throw increases by the extension of the cam 56. The beginning and ending positions of the components of the advancing cam mechanism are set forth in FIG. 3. Arrows illustrate the direction of motion of the components. Solid lines in FIG. 3 depict the cam 56 in the down position at the beginning of the stroke and the thruster tower length is shorter at the start, which translates into higher starting torque. The clutch cam 76 on roller clutch 72 is at the greatest distance from the center of the drive shaft 80 at the beginning of the stroke, also shown in solid lines. This provides for the greatest mechanical advantage at the beginning of the cycle when the load is greatest. In addition, the extension of cam 76 allows for greater throw in the main drive gear 80 in that by its extension it increases the distance of rotation over that of clutches alone. In this design, the cam 76 gives an extra amount of rotation on the drive axle as shown in dashed lines.

At the beginning of the stroke, the cam advancing gear 40 increases in its forward rotation over the fixed lower gear 52 and the advancing cam 56 begins to arch higher pulling more chain or cable 60 thereby producing more rotation of the main drive shaft 80. At the end of the stroke, the advancing cam 56 is fully extended and the torque produced is at a minimum. However, the length of cable or chain 60 that is pulled by the thruster arm 18 and cam 56 across the clutch 72 is maximized. Since the advancing cam has an increasing arch, maximum throw at the end of the stroke is observed propelling the drive system even faster at the end of the stroke.

FIG. 3, also illustrates the motion of the thruster foothold 22 or 24. The thruster foothold is fixed upon the thruster arm 18 via a swivel 82 within the foothold 22. A pin or connector 84 in the center of swivel 82 holds the foothold in place and allows the top surface of the foothold to remain level as the arm 18 changes angles. As the thruster motion is going up and down, the thruster arm 18 is at angles opposing the level foot. The swivel thruster foothold 22 allows the foot to remain somewhat level while the motioned thrusting action is occurring. The identical structure is present for foothold 24 on thruster arm 20.

FIG. 4 is an alternative embodiment of the invention where the roller clutches lack the clutch cams 76 or 78. The direction of the pull of chain or cable 60 is indicated by arrows. Because of the efficiency of the advancing cam mechanism, the diameter of the circular clutch can be reduced without sacrificing performance thereby providing greater efficiency.

It should be readily apparent that the thruster system can be geared for any number of applications. In yet another embodiment, chain 60 and 64 turns a sprocket which is directly connected to drive shaft 80 or to the drive wheel 14. FIG. 5 schematically depicts the advancing cam mechanism configured to midsection multistage gearing. The advancing cam mechanism turns a main drive sprocket 86 which turns the mid section multi stage gearing 88. The output ratio of output sprocket 90 is determined by the size of the main drive sprocket 86 and the size of the mid section gearing 88. The torque produced by the advancing cam mechanism permits the use of a larger drive sprocket than would be used in a rotary pedal application.

The configuration of the alternative embodiment found in FIG. 6 allows the advancing cam mechanism to transfer torque directly to the output. FIG. 6 depicts a set of drive sprockets 92 on input drive shaft 80 with a single output sprocket 94. FIG. 7 shows multiple drive sprockets 96 coupled to input shaft 80 and multiple output sprockets 98. In this configuration, ratio changes can occur at both the input and the output.

Alternatively, the main input shaft 80 could turn a helical or spiral gear which would turn a direct drive output shaft to a conventional geared transmission at the drive wheel as shown in FIG. 8.

Referring now to Figure 9, the thruster system of the present invention is coupled with the sliding ratio drive transmission. In FIG. 9, main drive shaft 80 is rotated when the advancing cam mechanism pulls cable 60 downwardly and the roller clutch 72 engages. Centered on one end of drive shaft 80 is the main drive disk 100 of the sliding ratio drive. Rotation of drive shaft 80 by the thruster arms 18 and 20 results in rotation of drive disk 100.

Torque transfer wheel 102 is positioned so that the circumference of the wheel frictionally engages drive disc 100. Drive disk 100 preferably has a durable rubber like substance (polymer) that provides a strong engagement surface for the torque transfer wheel 102 to allow the wheel to efficiently transfer torque to the output drive shaft 104. The output drive shaft 104 is preferably spleened to allow wheel 102 to slide freely along shaft 104 and rotate the shaft at the same time . The torque transfer wheel 102 slides back and fourth on the spleen drive shaft 104 along the horizontal path to vary the position of engagement on drive disk 100. The torque transfer wheel 102 is moved by a generally "U" shaped wheel guide 106, which positions the transfer wheel 102 along output shaft 104 in either direction. Wheel guide 106 and transfer wheel 102 are precisely positioned on the drive disk 100 and spleened output shaft 104 by a threaded positioning shaft 108 operated manually or electrically by a servo 110. A main support housing 112 supports the spleen output drive shaft 104 and the transfer wheel 102.

FIG. 10, is a top view of one preferred embodiment having the advancing cam mechanism and a sliding ratio drive transmission. Main drive disk 100 can be been arbitrarily numbered denoting various distances from the center radiating out to the periphery of disk 100. C1 being near the center of the disk and C9 being nine inches from C1. However, torque transfer wheel 102 can be positioned at any point on drive disk 100. As the transfer wheel 102 starts from a position nearest the center of disk 100, designated C1 , the transmission is at its lowest ratio and the transfer wheel will rotate comparatively slowly. When transfer wheel 102 reaches the outer end of the disk 100 at position C9, it has the highest ratio of input to output and the highest speed.

This process would be similar to first gear at C1 and as the transfer wheel 102 slides along the spleen shaft 104 towards the outer diameter of the disk 100 at position C9; it begins to increase in output speed.

The following is an example of the ratio differences between C1 and C6 given selected diameters and circumferences of the torque transfer wheel 102 and drive disk 100. C1 , as a starting point, will be viewed as first gear. If C1 has a radius from the center of the main drive disk of 2 inches, then the converted circumference would approximately equal 12.58 inches. If the torque transfer wheel has a radius of 1.25 inches then the circumference of the wheel 102 would approximately equal 7.87 inches. To find the rotational ratio of the torque transfer wheel 102 at C1 , one must divide the circumference at C1 by the circumference of transfer wheel 102. This gives the ratio of 1.60 to 1 , which means that the torque transfer wheel 102 rotates 1.60 times to the single rotation at C1 of disk 100. As the torque transfer wheel 102 moves along the horizontal path of the fixed spleen output shaft 104, it begins to speed up in its rotation. As the wheel reaches the C6 position on the drive disk, the radius is 6 inches and the circumference at C6 equals 37.752 inches. The rotational ratio at the C6 position, dividing the circumferences 7.87 into 37.752, equals a ratio of 4.79 to 1. That means that the torque transfer wheel 102 rotates 4.79 times to one revolution of the drive disk 100 at C6. It should be apparent that the dimensions of the drive disk 100 and transfer wheel 102 can be manipulated to provide an infinite number of ratios as needed depending on the application.

FIG. 11 and FIG. 12 are sectional perspective views of the sliding ratio drive transmission of the present invention. It can be seen that transfer wheel 102 can be incrementally positioned on the surface of drive disk 100. In one embodiment, the drive disk 100 may have a taper or groove towards the center by the spleen drive shaft support housing 112 where transfer wheel 102 may disengage from the disk. This allows for transfer wheel 102 to be in a neutral position when the vehicle is at a stand still and the disk 100 is in motion. This neutral function also allows for stationary or in motion charging of the drive disk, which will allow for a torque build up if needed prior to initiating motion.

As seen in FIG. 12, the clutch bearings 72 or 74 are on the drive side opposite the torque transfer wheel 102. However, any location along input drive shaft 80 is acceptable. The roller clutches 72 and 74 allow disk 100 to spin freely when no torque is applied to the torque transfer wheel 102 once the disk 100 has been put in circular motion, or it allows for a higher rpm to occur while in motion at a fixed area on the drive disk 100. FIG. 13 is a sectional view of the transmission showing drive shaft 80, drive disk 100 and the output sections. In FIG. 13, the thickness of drive disk 100 may vary depending on the application to which it is used. Disk 100 can be fabricated from a variety of materials: such as aluminum, composite fiber, etc. depending upon its application. Drive disk 100 has a hole in the center, which supports an inner sleeve 114, which slides on input drive shaft 80 in the preferred embodiment. This movement along shaft 80 is for the purpose of bringing disk 100 into contact with and applying pressure to torque transfer wheel 102. As also seen in FIG. 16, tension spring 116 maintains the proper pressure on disk 100 to ensure proper contact between wheel 102 and the face of disk 100. Screw ring 118 maintains the proper pressure against spring 116. The design may incorporate either a single disk or may employ a second disk that adds additional pressure against the ball drive device (not shown).

FIG. 13 also shows the device which provides the lateral translation of the torque transfer wheel 102 along the fixed spleen output shaft 104. This lateral movement is accomplished by threadably screwing guide 106 along positioning shaft 108 which in turn moves wheel 102 along the output shaft 104.

It is preferred that drive disk 100 have the physical properties of a flywheel as it builds up speed. FIG. 14 and FIG. 15 show the preferred embodiment of drive disk 100 . Placed radially from the center of the disk are rods 120 which are fixed to disk 100. Weighted rings 122 are disposed over rods 120 and can slide freely along the rods. Rotation of disk 100 will apply force on rings 122 to cause the rings to move outwardly from the center of the disk towards the periphery. Springs 124 increasingly resist the movement of rings 122 along rods 120. The lateral expansion of mass while disk 100 is in motion by rings 122 helps maintain the energy applied to the disk from the advancing cam mechanism and tempers fluctuations in output shaft speeds from inconsistent input shaft speeds. FIG. 16 is a partial front view of the transmission shown mounted on the drive shaft 80. Also shown is a threaded area 126 for screw ring 118 and tension spring 116. which allows the main drive disk 100 to slide under spring pressure against the torque transfer wheel 102. The sliding spleen area 128 of shaft 80 allows for the main drive disk 100 to move freely to apply pressure upon the torque transfer wheel 102. This is accomplished by the sleeve insert 114 that is pressed into the main drive disk.

FIG. 17 is a side view of the preferred embodiment of torque transfer wheel 102 engaging drive disk 100 at a right angle to the drive disk. This is where the torque transfer occurs. Free spinning tops 130 and 132 are part of the peripheral surface of wheel 102 and engage the surface of disk 100. The movement of tops 130 and 132 allow transfer wheel 102 to horizontally track along disk 100 while under load without withdrawing wheel 102 from engagement with disk 100. Thus, while the wheel 102 stays fixed to disk 100 performing its rotational function as a torque transfer wheel, tops 130 and 132 allow the wheel to slip horizontally resulting in a ratio increase.

Free spinning tops 130 and 132 have a cylindrical members 134 and 136 which fit into cylindrically shaped sockets within wheel 102. Each top has an arcuate cap which has the same curvature as other sections of wheel 102 and will smoothly engage disk 100. Cylindrical members 134 and 136 are preferably disposed within a bearings 138 and 140 respectively which allow tops 130 and 132 to freely spin around the central axis of the cylindrical members. Caps 142 and 144 are preferably supported by thruster washers 146 and 148 within the sockets. Thruster washers 146 and 148 permit rotation of in a horizontal plane while under vertical pressure. As can be seen in FIG. 18, the tops 130 and 132 are secured to the sockets by retaining bolts 150 and 152 through bolt access holes 154 and 156.

As lateral force is applied to torque transfer wheel 102 by wheel guide 106, tops 130 and 132 rotate allowing wheel 102 to slide horizontally along output shaft 104 while under load. There is a shift zone of approximately 12° in which rotation of top 130 can occur and a second zone in which rotation of top 132 can occur. The lateral force exerted on transfer wheel 102 by 106 in either direction is timed to correspond with the shift zones for each of the tops. Preferably, servo 110 is not activated until tops 130 or 132 on wheel 102 are properly positioned. The position of the wheel may be determined mechanically or electronically. In one embodiment a pair of holes 158 and 160 for each top are made in wheel 102 to allow laser light to activate a receptor triggering the shifting event.

It can be seen in FIG. 17 and FIG.18 that the center 162 of transfer wheel 102 can receive a sleeve insert 164, which slidably engages the output spleen shaft 104. This sleeve insert 164 preferably has internal projections and grooves matching the spleen shaft so that a tight rotational fit is provided while horizontal travel along the shaft is unrestricted. Alternatively, the shaft and insert may have a square or octagonal cross section. The inside of the sliding insert 164 is lubricated to achieve smooth sliding along the shaft 104 while torque is transferred from the drive disk 100 to the torque transfer wheel 102 to the spleen output shaft 104. The lubrication can be provided directly by grease or oil, while alternate materials or structures may be employed to reduce the sliding friction, such as UHMC plastic bearing surfaces or metal bearings.

FIG.19 is a top view of the socket on wheel 102 that receives the free spinning top 130, bearing 138, thruster washer 146 and retaining bolt 150. The free spinning top 130 is removed in this view.

While FIG.17 and FIG. 18 show a torque transfer wheel 102 with two spinning tops, the number of spinning tops can vary depending on the application and the diameter of the transfer wheel 102.

FIG. 20 depicts an alternative configuration of where drive shaft 166 is directly attached to a pair of conventional alternating pedals 168 to rotate drive disk 170. Drive shaft 166 rotates drive disk 170 which drives output shaft 172. One skilled in the technical arts relating to power transmission will immediately recognize that numerous structural variations may be employed while still adhering to the principles disclosed for the advancing cam mechanism and sliding ratio drive of the current invention. Accordingly, it will be seen that this sliding ratio drive provides a power transmission device whereby rotational speed or torque may be variably converted from an input to an output. Although the description above contains many specificities, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention. Thus the scope of this invention should be determined by the appended claims and their legal equivalents.

Claims

CLAIMS What is claimed is:

1. A human powered vehicle, comprising: (a) a frame; (b) a plurality of wheels, at least one of said wheels being a drive wheel, each wheel rotatably coupled to the frame; and

(c) a thruster drive system coupled to said frame and to said drive wheel.

2. A vehicle as recited claim 1 , wherein said thruster drive system comprises:

(a) a pair of elongated reciprocating levers pivotally mounted to said frame; and

(b) an advancing cam mechanism coupled to said levers and to said drive wheel.

3. A vehicle as recited in claim 2, wherein said thruster drive system further comprises:

(a) a drive shaft coupled to the drive wheel; and (b) a unidirectional clutch coupled to the drive shaft, said levers coupled to the clutch.

4. A vehicle as recited in claim 3, wherein said unidirectional clutch comprises a cam.

5. A vehicle as recited in claim 2, wherein said thruster drive system further comprises:

(a) a drive shaft coupled to said levers;

(b) a sprocket coupled to the drive shaft, said levers coupled the drive shaft; and

(c) a drive chain coupled to the sprocket and to the drive wheel.

6. A vehicle as recited in claim 2, wherein said thruster drive system further comprises:

(a) a drive shaft coupled to said levers;

(b) an output shaft coupled to said drive wheel; and (c) a drive gear coupled to the drive shaft and the output shaft.

7. A vehicle as recited in claim 2, wherein said thruster drive system further comprises a transmission coupled to said advancing cam mechanism and to said drive wheel.

8. A vehicle as recited in claim 7, wherein said transmission comprises a sliding ratio drive transmission coupled to said advancing cam mechanism and to said drive wheel.

9. A vehicle as recited in claim 1 , further comprising means for steering the vehicle.

10. A human powered drive train, comprising:

(a) a housing; (b) a thruster drive system within said housing; and

(c) an output shaft coupled to said thruster drive system.

11. A drive train as recited in claim 10, wherein said thruster drive system comprises: (a) at least one lever arm having an advancing cam mechanism;

(b) a drive shaft;

(c) a unidirectional clutch coupled between the drive shaft and the advancing cam mechanism; and

(d) a drive cable coupled to the advancing cam mechanism and to the housing and engaging the clutch wherein rotational motion is imparted to the drive shaft by the clutch when drawn through the clutch, and wherein rotation of said drive shaft imparts rotating motion to the output shaft.

12. A drive train according to claim 10, wherein said thruster drive system comprises: a) at least one lever arm; having an advancing cam mechanism; b) a output shaft; and c) a sprocket coupled to the output shaft and the advancing cam mechanism.

13. A drive train according to claim 10, wherein said thruster drive system comprises: a) at least one lever arm having an advancing cam mechanism; b) an output shaft; and c) a transmission coupled to the output shaft and the advancing cam mechanism; whereby the output shaft is rotated by the transmission.

14. A sliding ratio drive apparatus for providing variable mechanical power conversion wherein power is rotationally input to the device which provides an output that is generated at a speed set to a variable ratio of the input speed, the apparatus comprising:

(a) a support housing; (b) a drive disk that rotates about a center pivot;

(c) a drive wheel with an engagement surface for engaging the surface of the drive disk wherein torque is transferred from one surface to the other;

(d) a fixed drive shaft on which the drive wheel is slidably engaged, and;

(e) a lateral translation device wherein the drive device can be moved in relation to the drive disk.

15. The sliding ratio drive of claim 14, further comprising a shaft support housing within which is rotatably retained the fixed drive shaft upon which is slidably retained the drive device which is held in a position substantially parallel to the drive disk.

16. The sliding ratio drive apparatus of claim 14 wherein the drive disk is formed as a substantially rigid disk attached to a shaft that is retained to allow rotation.

17. The drive disk of claim 16, wherein the drive disk is attached to a main support axle through which power may be conveyed.

18. The support axle of claim 17, wherein the drive disk is configured for attachment to the main shaft by a spring tension device.

19. A transmission comprising: a) a rotating disk having front and back surfaces; b) means for causing rotation of said disk; [or input shaft] c) a drive wheel having a circumferential engagement surface, said wheel engagement surface positioned to frictionally engage the rotating disk; d) a drive shaft slidably coupled with the drive wheel; whereby said drive wheel can be placed at any point along the length of the drive shaft; and e) means for sliding said drive wheel along the length of said drive shaft.

20. A transmission of Claim 19 further comprising a means for incrementally moving the drive wheel along the drive shaft while said wheel is engaged with the front surface of the drive disk.

21. A transmission of Claim 20 further comprising a means for determining the position of points along the circumference of the drive wheel while said wheel is rotating.

22. A transmission of Claim 19 wherein said means for causing rotation of said disk is a pair of foot actuated pedals disposed on either side of the drive disk.

23. A power transmission apparatus with infinitely adjustable drive ratios comprising;

(a) a drive disk that rotates about a center pivot;

(b) a drive device with an engagement surface for engaging the surface of the drive disk wherein torque is transferred from one surface to the other;

(c) a fixed drive shaft on which the drive device is slidably engaged;

(d) a lateral translation device wherein the drive device can be moved in relation to the drive disk, and;.

(e) a base member for mounting the members above whereby the rotational input power is converted through and infinite number of ratios to an output power.