CA2182623A1 - Bicycle having a cyclicly variable gear ratio pedal response - Google Patents
Bicycle having a cyclicly variable gear ratio pedal responseInfo
- Publication number
- CA2182623A1 CA2182623A1 CA002182623A CA2182623A CA2182623A1 CA 2182623 A1 CA2182623 A1 CA 2182623A1 CA 002182623 A CA002182623 A CA 002182623A CA 2182623 A CA2182623 A CA 2182623A CA 2182623 A1 CA2182623 A1 CA 2182623A1
- Authority
- CA
- Canada
- Prior art keywords
- bicycle
- sprocket
- gear ratio
- non circular
- cyclicly
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
- B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
- B62M9/04—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio
- B62M9/06—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
- B62M1/00—Rider propulsion of wheeled vehicles
- B62M1/36—Rider propulsion of wheeled vehicles with rotary cranks, e.g. with pedal cranks
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
- B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
- B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
- B62M9/04—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio
- B62M9/06—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like
- B62M9/08—Transmissions characterised by use of an endless chain, belt, or the like of changeable ratio using a single chain, belt, or the like involving eccentrically- mounted or elliptically-shaped driving or driven wheel; with expansible driving or driven wheel
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62M—RIDER PROPULSION OF WHEELED VEHICLES OR SLEDGES; POWERED PROPULSION OF SLEDGES OR SINGLE-TRACK CYCLES; TRANSMISSIONS SPECIALLY ADAPTED FOR SUCH VEHICLES
- B62M9/00—Transmissions characterised by use of an endless chain, belt, or the like
- B62M9/16—Tensioning or adjusting equipment for chains, belts or the like
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Automatic Cycles, And Cycles In General (AREA)
Abstract
This invention relates to a bicycle having a foot pedal rotation to rear wheel rotation gear ratio which varies throughout the 360 degree angular rotation of the foot pedals.
The gear ratio varies cyclicly through a foot pedal synchronized non circular sprocket, positively engaging a chain and sprocket power transmission system.
The shape and orientation of the non circular sprocket is designed to optimize the muscular effort to bicycle forwardly propulsive ratio throughout the 360 degree of angular pedal rotation.
The non circular sprocket or sprockets, may be retro fitted onto existing prior art bicycles presently having one or more a circular sprockets and a chain slack take-up mechanism.
The gear ratio varies cyclicly through a foot pedal synchronized non circular sprocket, positively engaging a chain and sprocket power transmission system.
The shape and orientation of the non circular sprocket is designed to optimize the muscular effort to bicycle forwardly propulsive ratio throughout the 360 degree of angular pedal rotation.
The non circular sprocket or sprockets, may be retro fitted onto existing prior art bicycles presently having one or more a circular sprockets and a chain slack take-up mechanism.
Description
' ~ 2 1 ~2623 Disclosure;
Bicycle havlng a cyclicly variable gear ratio pedal response.
The following disclosure describes an invention relatlng to a muscular powered wheeled device, more particularly a foot pedal actuated bicycle that more adaptively and more efficiently derives power from the muscular efforts of the cyclist through a cyclicly variable gear ratio and wherein the gear ratio depends partially on the angular position of the pedals.
Most prior art bicycles are provided with an 10 adjustable variable gear ratio power transmission system comprising one or more, forwardly disposed foot pedal actuated, different diameter circular sprockets, a chain and one or more rearwardly disposed different diameter circular sprockets, 15 driving the rear wheel of the bicycle, providing forward propulsion.
The cyclist may select any gear ratio to optimize the adaptation of muscular effort to forward propulsion as dictated by conditions such as the 20 ascend or descent of the bicycle, wind resistance and speed.
A desired gear ratio may be selected by urging a forwardly dlsposed portion of the chain onto one of a plurality of foot pedal actuated different diameter forwardly disposed circular sprockets and by selectably urging a rearwardly disposed portion of the chain onto one of a plurality of different diameter rearwardly disposed circular, rear wheel driving sprockets.
Sprocket selection i8 made by positioning one or more manually operated levers, attached to 10 conveniently lcre~s~hle portions of the bicycle, which actuate one or more chain posltioning devices, commonly known as derailleurs.
Since variou8 different gear ratio's result from a constant length of chain, engaging different 15 diameter sprockets, a slack take-up device is re~uired to maintain a minimum of tension and to provide guidance to a non power transmitting portion of the chain.
This slack take-up device is normally incorporated 20 into a rearwardly disposed derailleur.
When referring to a gear ratio, one might consider this matter in terms of propulsive force or in terms of travel distance.
For the purpose of a clear understanding throughout 25 this disclosure, a high gear ratio is considered in terms of travel dlstance, meaning, a unit of pedal movement providing a maximum distance of bicycle ~ 2 1 ~2623 forward v, ~ and conversely, a low gear ratio meaning a unit of pedal movement providing a minimum of bicycle forward v ~
~o more fully appreciate and understand the advantages of a bicycle having a cyclicly variable gear ratio pedal response over a bicycle having a prior art forwardly disposed circular sprocket, it is desirable to examine the relationship between forwardly propulsive force and foot pedal actuation 10 during various angular pedal positlons.
When in reference to a foot pedal actuated wheeled device, both foot pedals are in the extreme upward/downward, vertical position, no amount of downwardly directed pedal pressure will result in 15 any forwardly propelling force.
Experienced cyclists however are able to exert a forwardly directed force onto the upward pedal and are able to exert a rearwardly directed force onto the downward pedal, providlng a bicycle forwardly 20 propelling force, while both pedals are substantially in the vertical position.
The muscular forces providing these forwardly and rearwardly directed pedal exerted forces are small in comparison to the more powerfull downwardly and 25 upwardly directed forces exerted onto the foot actuated pedals, however, the ability to provide forward and rearward pedal r- ~v~ ~ ifi substantial, 2 t 82623 -' ~
indicating that a lower gear ratio at this pedal position will adapt this muscular effort to maximally increase the bicycle forwardly propulsive force.
It is an object of this invention to provide a muscle powered wheeled device, more particularly a bicycle that further optimizes muscular effort by having a gear ratio varying cyclicly throughout 360 degree of foot pedal rotation, advantageously 10 ratioed to optimize the forward propulsion resulting from muscular effort throughout the 360 degree of foot pedal rotation, beyond prior art optimization resulting from selecting a constant 360 degree optimum gear ratio.
15 Another object of this invention is to provide the cyclist a selection between a conventional forwardly dispoaed circular sprocket and a forwardly disposed non circular sprocket according to this invention, using a conventional derailleur system.
20 Still another object of this invention is to provide a bicycle providing the cyclist a choice of varying degrees of cyclicly variable ratio pedal responses.
Still one more object of this invention is to provide a bicycle, providing improved performance 25 through a more efficient muscularly adaptive cyclicly variable gear configuration at a minimum increase in manufacturing cost.
Still another ob~ect of this invention is to provide a low cost retrofitable part to modify a bicycle, manufactured according to prior art, providing improved performance through a cyclicly variable gear configuration.
The essential elements of this invention comprise:
at least one or more non circular forwardly disposed sprockets, centrally secured to an axle, rotatably driven by levers which terminate outwardly in 10 circularly mobile foot actuated pedals. The non circular sprockets having a minimum diameter, substantially parallel to the longitudinal axis of the pedal actuated levers and having a maximum diameter substantially perpendicular to the 15 longitudinal axis of the pedal actuated levers, in combination with a chain slack take-up mechanism, transferring the forces exerted onto the pedal into a forwardly directed propulsive force, advantageously ratioed, cyclicly varying in relation to the angular 20 position of the pedals relative to the longitudinal axis of the bicycle.
These and more specific objects and advantages will become apparent from the following description when taken in conjunction with the accompanying drawings 25 forming a part thereof, wherein identical element~
will be identified by the same numerals in each of the drawings shown.
2 ~ 82623 -Brief description of the drawings;
Figure 1 is a side elevational view of a bicycle having foot actuated pedals, pedal activated levers, a forwardly disposed non circular sprocket according to this invention and a sprocket and chain power transmission system, showing the longitudinal axis of the pedal actuated levers in a substantially vertical position.
Figure 2 is an expanded view of a portion of figure 10 1, showing the longitudinal axis of the pedal actuated levers and the forwardly disposed non circular sprocket, identical to the position shown in figure 1.
Figure 3 is an expanded view of a portion of figure 15 1, showing the longitudinal axis of the pedal actuated levers and the forwardly disposed non circular sprocket having advanced 45 degrees counter clockwise as compared to the position shown in figure 2.
20 Figure 4 is an expanded view of a portion of figure 1, showing the longitudinal axis of the pedal actuated levers and the forwardly disposed non circular sprocket in a substantially horizontal position.
In the drawings:
Referring to the drawings with the aid of reference numerals;
Figure 1 is a side elevational view of a bicycle s~ 2 1 82623 having foot actuated pedals, pedal actuated levers, rotatably secured to a frame by an axle and fixedly secured to a forwardly disposed non circular sprocket according to this invention and a chain power transmission system, showing the pedal activated levers in a substantially vertical position and wherein the bicycle is impressed onto a downwardly disposed horizontal surface identified a8 10-11, of which 10 is a forwardly disposed portion 10 of surface 10-11 and of which 11 is a rearwardly disposed portion of surface 10-11. For purposes of reference, the longitudinal axis of the bicycle is parallel to surface 10-11.
The bicycle having a forwardly disposed wheel 12, 15 having spokes 12a, 12b, 12c and 12d, rotatably secured to steering column 13 via axle 14, to rollably and steerably engage surface 10-11, rearwardly disposed wheel 15, having spokes 15a, 15b, 15c and 15 d, rotatably secured to frame 16, 20 via axle 17 and fixedly secured to at least one rearwardly disposed sprocket 18, supported by surface 10-11, transmitting a forwardly propulsive force to surface 10-11, providing forward propulsion to the bicycle.
25 ~andle bars 19 assist guiding the bicycle along a desirable traiectory while saddle 20, allows the cyclist to muscularly relax when less than a maximum downwardly directed pedal pressure is required.
'' ~ 2 1 82623 A sprocket and chain power transmission system comprising foot actuated pedals 21-22, levers 23-24, lever axle 25, rigidly attached to levers 23-24 and to forwardly disposed non circular sprocket 26 and rotatably attached to frame 16, showing the longitudinal axis of the foot pedal actuated levers in the near vertical posltion. The chain is generally identified as 27. The propulsive portion of the chain is identified as 28-29 and the non 10 propulsive portion of the chain is identified as 30-31.
A forwardly disposed derailleur, identified as 32 allows the cyclist to select between one or more different diameter circular sproc~ets and one or 15 more non circular sprockets, which may have a different circumference, a different graduation and a different orientation.
A rearwardly disposed derailleur and chain slack take-up device, identified as 33 allows the cyclist 20 to select various conventional rearwardly disposed circular sprockets to provide the most desirable gear ratio.
Figure 2 is an expanded view of the relevant portions of figure 1, more clearly and detailedly 25 showing a portion of pedal activated levers 23-24 and forwardly disposed non circular sprocket 26 according to this invention and a chain power tran8mission system.
' ~ 21~2623 The gear ratio associated with the the angle of rotation as shown is proportional to the length of the radius perpendicular to the forwardly disposed propulsive portion of chain 27 and is identified as 5 34.
Figure 3 is an expanded view of foot pedal actuated levers 23-24 and forwardly disposed non circular sprocket 26, showing levers 23-24 and non circular sprocket 26 havlng rotated 45 degrees of angle 10 counter clockwise relative to the view shown in figure 2.
The gear ratio associated with the the angle of rotation as shown is proportional to the length of the radius perpendicular to the forwardly disposed 15 propulsive portion of chain 27 and is identified as 35.
It is clear from the geometry of the non circular sprocket that radius 35 is longer than radius 34, indicating an increase in the gear ratio.
20 Figure 4 is an expanded view of the foot pedal actuated levers, and forwardly disposed non circular sprocket 26, showing foot actuated pedals 21-22, and pedal actuated levers 23-24, having rotated 90 degrees of angle counter clockwise relative to the 25 view shown in figure 2 and having reached a substantially horizontal position.
The gear ratio associated with the the angle of _g_ rotation as shown is proportional to the length of the radius perpendicular to the forwardly dlsposed propulsive portion of chain 27 and is identified as 36.
Gear ratio determining radius 36 exceeds radii 34 and 35 , providing maximum bicycle forward travel for a cyclist's maximum downward pressure.
The foregoing is a description of the gradual increase in the gear ratio during one quadrant of 10 pedal travel, wherein pedal 21 travels counter clockwise from the extreme upward position to the extreme forward position and wherein pedal 22 travels from the extreme downward position to the extreme rearward position. In the following quadrant 15 of pedal travel, wherein pedal 21 travels from the extreme forward position to the extreme downward position and wherein pedal 22 travels form the extreme rearward position to the extreme upward position, the gear ratio gradually decreases, a 20 process cyclicly repeating itself, assigning a predetermined gear ratio to each angular degree of pedal position.
It is obvious that many alternative embodiments can be envisioned, by anyone skilled in the art. More 25 particularly, the axis orientation of the non circular aprockets, the degree of graduation of the non circular sprocket, which may be elliptical, oval or any advantageous graduation, the combination of circular and non circular sprockets, the number of non circular sprockets, and the various embodiments of slack take-up devices and slack take-up damping devices, without departing from the spirit of this invention. Furthermore, this invention relates to tricycles and other foot pedal activated wheeled vehicles.
Therefore the scope of this invention is not limited 10 to the exact embodiments shown but only as indicated by the appended claims.
Bicycle havlng a cyclicly variable gear ratio pedal response.
The following disclosure describes an invention relatlng to a muscular powered wheeled device, more particularly a foot pedal actuated bicycle that more adaptively and more efficiently derives power from the muscular efforts of the cyclist through a cyclicly variable gear ratio and wherein the gear ratio depends partially on the angular position of the pedals.
Most prior art bicycles are provided with an 10 adjustable variable gear ratio power transmission system comprising one or more, forwardly disposed foot pedal actuated, different diameter circular sprockets, a chain and one or more rearwardly disposed different diameter circular sprockets, 15 driving the rear wheel of the bicycle, providing forward propulsion.
The cyclist may select any gear ratio to optimize the adaptation of muscular effort to forward propulsion as dictated by conditions such as the 20 ascend or descent of the bicycle, wind resistance and speed.
A desired gear ratio may be selected by urging a forwardly dlsposed portion of the chain onto one of a plurality of foot pedal actuated different diameter forwardly disposed circular sprockets and by selectably urging a rearwardly disposed portion of the chain onto one of a plurality of different diameter rearwardly disposed circular, rear wheel driving sprockets.
Sprocket selection i8 made by positioning one or more manually operated levers, attached to 10 conveniently lcre~s~hle portions of the bicycle, which actuate one or more chain posltioning devices, commonly known as derailleurs.
Since variou8 different gear ratio's result from a constant length of chain, engaging different 15 diameter sprockets, a slack take-up device is re~uired to maintain a minimum of tension and to provide guidance to a non power transmitting portion of the chain.
This slack take-up device is normally incorporated 20 into a rearwardly disposed derailleur.
When referring to a gear ratio, one might consider this matter in terms of propulsive force or in terms of travel distance.
For the purpose of a clear understanding throughout 25 this disclosure, a high gear ratio is considered in terms of travel dlstance, meaning, a unit of pedal movement providing a maximum distance of bicycle ~ 2 1 ~2623 forward v, ~ and conversely, a low gear ratio meaning a unit of pedal movement providing a minimum of bicycle forward v ~
~o more fully appreciate and understand the advantages of a bicycle having a cyclicly variable gear ratio pedal response over a bicycle having a prior art forwardly disposed circular sprocket, it is desirable to examine the relationship between forwardly propulsive force and foot pedal actuation 10 during various angular pedal positlons.
When in reference to a foot pedal actuated wheeled device, both foot pedals are in the extreme upward/downward, vertical position, no amount of downwardly directed pedal pressure will result in 15 any forwardly propelling force.
Experienced cyclists however are able to exert a forwardly directed force onto the upward pedal and are able to exert a rearwardly directed force onto the downward pedal, providlng a bicycle forwardly 20 propelling force, while both pedals are substantially in the vertical position.
The muscular forces providing these forwardly and rearwardly directed pedal exerted forces are small in comparison to the more powerfull downwardly and 25 upwardly directed forces exerted onto the foot actuated pedals, however, the ability to provide forward and rearward pedal r- ~v~ ~ ifi substantial, 2 t 82623 -' ~
indicating that a lower gear ratio at this pedal position will adapt this muscular effort to maximally increase the bicycle forwardly propulsive force.
It is an object of this invention to provide a muscle powered wheeled device, more particularly a bicycle that further optimizes muscular effort by having a gear ratio varying cyclicly throughout 360 degree of foot pedal rotation, advantageously 10 ratioed to optimize the forward propulsion resulting from muscular effort throughout the 360 degree of foot pedal rotation, beyond prior art optimization resulting from selecting a constant 360 degree optimum gear ratio.
15 Another object of this invention is to provide the cyclist a selection between a conventional forwardly dispoaed circular sprocket and a forwardly disposed non circular sprocket according to this invention, using a conventional derailleur system.
20 Still another object of this invention is to provide a bicycle providing the cyclist a choice of varying degrees of cyclicly variable ratio pedal responses.
Still one more object of this invention is to provide a bicycle, providing improved performance 25 through a more efficient muscularly adaptive cyclicly variable gear configuration at a minimum increase in manufacturing cost.
Still another ob~ect of this invention is to provide a low cost retrofitable part to modify a bicycle, manufactured according to prior art, providing improved performance through a cyclicly variable gear configuration.
The essential elements of this invention comprise:
at least one or more non circular forwardly disposed sprockets, centrally secured to an axle, rotatably driven by levers which terminate outwardly in 10 circularly mobile foot actuated pedals. The non circular sprockets having a minimum diameter, substantially parallel to the longitudinal axis of the pedal actuated levers and having a maximum diameter substantially perpendicular to the 15 longitudinal axis of the pedal actuated levers, in combination with a chain slack take-up mechanism, transferring the forces exerted onto the pedal into a forwardly directed propulsive force, advantageously ratioed, cyclicly varying in relation to the angular 20 position of the pedals relative to the longitudinal axis of the bicycle.
These and more specific objects and advantages will become apparent from the following description when taken in conjunction with the accompanying drawings 25 forming a part thereof, wherein identical element~
will be identified by the same numerals in each of the drawings shown.
2 ~ 82623 -Brief description of the drawings;
Figure 1 is a side elevational view of a bicycle having foot actuated pedals, pedal activated levers, a forwardly disposed non circular sprocket according to this invention and a sprocket and chain power transmission system, showing the longitudinal axis of the pedal actuated levers in a substantially vertical position.
Figure 2 is an expanded view of a portion of figure 10 1, showing the longitudinal axis of the pedal actuated levers and the forwardly disposed non circular sprocket, identical to the position shown in figure 1.
Figure 3 is an expanded view of a portion of figure 15 1, showing the longitudinal axis of the pedal actuated levers and the forwardly disposed non circular sprocket having advanced 45 degrees counter clockwise as compared to the position shown in figure 2.
20 Figure 4 is an expanded view of a portion of figure 1, showing the longitudinal axis of the pedal actuated levers and the forwardly disposed non circular sprocket in a substantially horizontal position.
In the drawings:
Referring to the drawings with the aid of reference numerals;
Figure 1 is a side elevational view of a bicycle s~ 2 1 82623 having foot actuated pedals, pedal actuated levers, rotatably secured to a frame by an axle and fixedly secured to a forwardly disposed non circular sprocket according to this invention and a chain power transmission system, showing the pedal activated levers in a substantially vertical position and wherein the bicycle is impressed onto a downwardly disposed horizontal surface identified a8 10-11, of which 10 is a forwardly disposed portion 10 of surface 10-11 and of which 11 is a rearwardly disposed portion of surface 10-11. For purposes of reference, the longitudinal axis of the bicycle is parallel to surface 10-11.
The bicycle having a forwardly disposed wheel 12, 15 having spokes 12a, 12b, 12c and 12d, rotatably secured to steering column 13 via axle 14, to rollably and steerably engage surface 10-11, rearwardly disposed wheel 15, having spokes 15a, 15b, 15c and 15 d, rotatably secured to frame 16, 20 via axle 17 and fixedly secured to at least one rearwardly disposed sprocket 18, supported by surface 10-11, transmitting a forwardly propulsive force to surface 10-11, providing forward propulsion to the bicycle.
25 ~andle bars 19 assist guiding the bicycle along a desirable traiectory while saddle 20, allows the cyclist to muscularly relax when less than a maximum downwardly directed pedal pressure is required.
'' ~ 2 1 82623 A sprocket and chain power transmission system comprising foot actuated pedals 21-22, levers 23-24, lever axle 25, rigidly attached to levers 23-24 and to forwardly disposed non circular sprocket 26 and rotatably attached to frame 16, showing the longitudinal axis of the foot pedal actuated levers in the near vertical posltion. The chain is generally identified as 27. The propulsive portion of the chain is identified as 28-29 and the non 10 propulsive portion of the chain is identified as 30-31.
A forwardly disposed derailleur, identified as 32 allows the cyclist to select between one or more different diameter circular sproc~ets and one or 15 more non circular sprockets, which may have a different circumference, a different graduation and a different orientation.
A rearwardly disposed derailleur and chain slack take-up device, identified as 33 allows the cyclist 20 to select various conventional rearwardly disposed circular sprockets to provide the most desirable gear ratio.
Figure 2 is an expanded view of the relevant portions of figure 1, more clearly and detailedly 25 showing a portion of pedal activated levers 23-24 and forwardly disposed non circular sprocket 26 according to this invention and a chain power tran8mission system.
' ~ 21~2623 The gear ratio associated with the the angle of rotation as shown is proportional to the length of the radius perpendicular to the forwardly disposed propulsive portion of chain 27 and is identified as 5 34.
Figure 3 is an expanded view of foot pedal actuated levers 23-24 and forwardly disposed non circular sprocket 26, showing levers 23-24 and non circular sprocket 26 havlng rotated 45 degrees of angle 10 counter clockwise relative to the view shown in figure 2.
The gear ratio associated with the the angle of rotation as shown is proportional to the length of the radius perpendicular to the forwardly disposed 15 propulsive portion of chain 27 and is identified as 35.
It is clear from the geometry of the non circular sprocket that radius 35 is longer than radius 34, indicating an increase in the gear ratio.
20 Figure 4 is an expanded view of the foot pedal actuated levers, and forwardly disposed non circular sprocket 26, showing foot actuated pedals 21-22, and pedal actuated levers 23-24, having rotated 90 degrees of angle counter clockwise relative to the 25 view shown in figure 2 and having reached a substantially horizontal position.
The gear ratio associated with the the angle of _g_ rotation as shown is proportional to the length of the radius perpendicular to the forwardly dlsposed propulsive portion of chain 27 and is identified as 36.
Gear ratio determining radius 36 exceeds radii 34 and 35 , providing maximum bicycle forward travel for a cyclist's maximum downward pressure.
The foregoing is a description of the gradual increase in the gear ratio during one quadrant of 10 pedal travel, wherein pedal 21 travels counter clockwise from the extreme upward position to the extreme forward position and wherein pedal 22 travels from the extreme downward position to the extreme rearward position. In the following quadrant 15 of pedal travel, wherein pedal 21 travels from the extreme forward position to the extreme downward position and wherein pedal 22 travels form the extreme rearward position to the extreme upward position, the gear ratio gradually decreases, a 20 process cyclicly repeating itself, assigning a predetermined gear ratio to each angular degree of pedal position.
It is obvious that many alternative embodiments can be envisioned, by anyone skilled in the art. More 25 particularly, the axis orientation of the non circular aprockets, the degree of graduation of the non circular sprocket, which may be elliptical, oval or any advantageous graduation, the combination of circular and non circular sprockets, the number of non circular sprockets, and the various embodiments of slack take-up devices and slack take-up damping devices, without departing from the spirit of this invention. Furthermore, this invention relates to tricycles and other foot pedal activated wheeled vehicles.
Therefore the scope of this invention is not limited 10 to the exact embodiments shown but only as indicated by the appended claims.
Claims (4)
1. A bicycle having a cyclicly variable gear ratio pedal response, comprising: a frame; pedals, foot actuated by the cyclist; levers, actuated by said pedals for rotating about a central axis; at least one forwardly disposed non circular sprocket; a lever axle, rotatably securing said levers to a forwardly disposed portion of said frame and rigidly securing said levers to said non circular sprocket; at least one rearwardly disposed sprocket; a rear wheel; an axle, rotatably securing said rear wheel to a rearwardly disposed portion of said frame and securing said rear wheel to said sprocket; a chain, positively engaging one forwardly disposed non circular sprocket and one rearwardly disposed sprocket; one or more slack take-up mechanisms, maintaining a minimum chain tension.
2 A bicycle having a cyclicly variable gear ratio pedal response, as defined in claim 1, wherein the minimum diameter of the non circular sprocket is approximately parallel to the longitudinal axis of the levers.
3 A bicycle having a cyclicly variable gear ratio pedal response, as defined in claim 1, wherein the non circular sprocket is oval shaped.
4 A bicycle having a cyclicly variable gear ratio pedal response, as defined in claim 1, wherein the non circular sprocket is elliptical.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002182623A CA2182623A1 (en) | 1996-08-02 | 1996-08-02 | Bicycle having a cyclicly variable gear ratio pedal response |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002182623A CA2182623A1 (en) | 1996-08-02 | 1996-08-02 | Bicycle having a cyclicly variable gear ratio pedal response |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2182623A1 true CA2182623A1 (en) | 1998-02-03 |
Family
ID=4158694
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002182623A Withdrawn CA2182623A1 (en) | 1996-08-02 | 1996-08-02 | Bicycle having a cyclicly variable gear ratio pedal response |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2182623A1 (en) |
-
1996
- 1996-08-02 CA CA002182623A patent/CA2182623A1/en not_active Withdrawn
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| AZWI | Withdrawn application |