| KR101159800B1 | 2012-06-26 | |||
| US6468178B1 | 2002-10-22 |
| Claims [Claim 1] Bicycle with bilateral sided drive mechanism having plurality of crankshafts at the front part, pair of crankshafts at the rear wheel and coupling shafts joining the crankpin bearings at the front and rear part in a way that crankshafts at the front, upon rotation using manual force, generate rotatary motion in the rear wheel and a novel robust rear bracket to secure the rear wheel with the frame while facilitating better bike kinematics. [Claim 2] Drive mechanism, as claimed in [Claim 1], comprising front part which includes a pair of drive assemblies each having plurality of integrally formed crankshafts, multipoint inter-drive-assembly-coupling mechanism, a pair of pedals, a pair of drive enclosure brackets each of which secure a drive assembly to the frame via bracket support, rear part which includes rear wheel assembly and plurality of front-rear-coupling shafts coupling the front and rear part. [Claim 3] Rear wheel assembly, as claimed in [Claim 2], comprises a wheel at the rear part of bicycle whose hub at each end is coaxially connected to flywheel shaft of a single cylinder crankshaft via a coaxial one way ratchet ball bearings with an arrangement such that outer ring or inner ring of the said ball bearing is coaxially connected to hub of the rear wheel and inner ring or outer ring respectively is connected coaxially to flywheel shaft of the said crankshaft, rotation of the crankshaft engages the wheel only to move in forward direction, crankpin bearing of crankshaft on one side is in opposite phase with respect to the crankpin bearing of crankshaft on the other side. [Claim 4] Each drive assembly, as claimed in [Claim 2], comprises of a special type of epicyclic gear which we refer as pivoted-slewing-bearing-epicyclic- gear, with plurality of integrally formed crankshafts each of whose crankpin bearing is synchronized into same phase as the crankshaft on the rear wheel on the side same as that of drive assembly. [Claim 5] Pivoted-slewing-bearing-epicyclic-gear, as claimed in [Claim 4], comprises a circular plate called as carrier plate having plurality of spur gears including planetary gears, a sun gear, satellite gears and far planet gears journalled to it and connected along its circumference to a internal toothed slewing bearing via U-shaped pegs, in arrangement such that center of sun gear is at the center of the carrier plate, carrier plate at its side containing sun gear is attached at its periphery to the outer ring of the said slewing bearing over-bridging gear ring with the help of U- shaped pegs such that slewing bearing is coaxial with Sun gear, each of planetary gears which are spur gears of equal radii is meshingly engaged with sun gear and gear ring of the slewing bearing, each satellite gear is meshingly engaged with two adjacent planetary gears and a far planet gear, each far planet gear is meshingly engaged with gear ring of the said slewing bearing and a satellite gear, and a pivot plate, which is an eared circular plate with radius equal to the average of outer and inner radius of gear ring, is attached at its rim to the gear ring at its outer side and is coaxially journalled to the outer side of the carrier plate. [Claim 6] Pivoted-slewing-bearing-epicyclic gear, described in [Claim 5], is constrained to follow the conditions that number of planetary gears, satellite gears and far planet gears used are three radius of planetary gears being greater than the radius of sun gear, satellite gears and far planet gears, satellite gears are of equal radii, far planet gears are of equal radii, centers of three planetary gears forms an equilateral triangle with its circumcenter being center of sun gear, centers of satellite gears and far planet gears falls on the perpendicular bisectors of the said triangle. [Claim 7] Each of the planetary gears of pivoted-slewing-bearing-epicyclic gear, claimed in [Claim 5], has metal peg is journalled at a point on its base circle such that planetary gears can additionally function as crankshaft with metal peg functions as its crankpin bearing, crankshaft thus formed at each planetary gear need to be of radius and in a phase equal to that of rear wheel crankshaft, mentioned in [Claim 3], on the same side of the bicycle. [Claim 8] Front-rear-coupling shaft, mentioned in [Claim 2], at each side of the bicycle is a set of maximum three coplanar straight shafts having their rear ends conjoined in way that each pair of adjacent shaft make equal angle at the joining point, and have conjoined end connected to the crankpin bearing of the rear crankshaft and each front end connected to the crankpin bearing of a planetary gear. [Claim 9] Multipoint inter-drive-assembly-coupling mechanism, mentioned in [Claim 2], consists of plurality of Z-shaped shafts each of whose ends are connected to top of crankpin bearings of a pair of coaxially parallel planetary gears on the drive assemblies with its middle arm coaxial with corresponding planetary gears. [Claim 10] Drive bracket support, claimed in [Claim 2] is a vertical rectangular metal plate, coplanar with bicycle frame, is attached at its upper side to bottom end of down tube and seat tube and have ball bearings mounted on its plane each of which coaxially houses middle arm of a inter-drive-assembly-coupling shaft, described in [Claim 9] [Claim 11] Each of the pair of drive enclosure bracket, as claimed in [Claim 2], comprises an enclosure which is in the form of cylinder, with its axis being perpendicular to the frame of the bicycle, attached at its inner side rim to drive bracket support, explained in [Claim 10], vertically sliced to have a rectangular opening facing rear part of the bicycle, with cylinder being of radius equal to the outer radius of slewing bearing and length approximately equal to distance between frame and a carrier plate, with opening big enough to provide space for the motion of front- rear-coupling shafts, a circular annular plate, attached to outer side rim of the said enclosure, to which outer ring of drive assembly is fastened, and a metal bar referred to as shaft stays connecting said rear part of circular annular plate to outer end of main bearing shaft of rear crank shaft explained in claim[3]. [Claim 12] A pedal, claimed in [Claim 2] is pivoted to the periphery of the pivot plate, claimed in [Claim 5], at its outer side. [Claim 13] Carrier plates, claimed in [Claim 5], can be fixed to be stationary by directly connecting it to the drive bracket support, described in [Claim 10], via rods. [Claim 14] Rear wheel support mechanism claimed in [Claim 1], comprises rear bracket, rear bracket support and a pair of hub fasteners, one on right side of rear wheel and one on left side of rear wheel. [Claim 15] Rear bracket comprises two V-shaped planar trusses parallel to the rear wheel with one truss located on right side of rear wheel and other located on left side of rear wheel. [Claim 16] Rear bracket support, which connects upper ends of both the V-shaped planar trusses of rear bracket to the bicycle frame, comprises two forward slanting A-shaped trusses and a tube extending rearwardly from the rear end of top tube wherein one A-shaped truss located on rear side of the seat tube is connected at its angled upper end to rear side of the said tube; other truss located on front side of the seat tube is connected at its angled upper end to the top tube; bottom ends of two arms of front and rear A-shaped trusses are connected to upper front ends and upper rear ends, respectively of rear bracket; [Claim 17] Each of V-shaped planar trusses, mentioned in [Claim 15], comprises two coplanar V-shaped rods arranged one behind the other parallel to the rear wheel and a V- shaped peg located on corresponding side of the rear wheel wherein each of V-shaped rods have acute angle bend facing the forward direction; angled corners of V-shaped rods lies on the upper rear side of axle of the rear wheel; angled corner of front side V-shaped rod is located vertically higher than that of rear side V-shaped rod; each of V-shaped rods have one arm extending downwards with their bottom ends fixedly connected to the main bearing shaft of the rear crank shaft on the corresponding side of the rear wheel; above mentioned downward extending rods may be suspension or rigid rod according to requirement; upper ends of rear and front V-shaped trusses are connected to bottom ends of corresponding side arms of rear and front A-shaped trusses respectively; V-shaped peg is attached at its angled corner to the angled corner of front side V- shaped rod at its rearward side and one arm as a rearward extension of lower arm of front side V-shaped rod with its upper end attached to upper arm of rear side V-shaped rod and other arm as a rearward extension of upper arm of front V-shaped rod with its lower end attached to lower arm of rear side V-shaped rod. [Claim 18] Each of hub fasteners, mentioned in [Claim 14], is right-angled metal strip with one arm, being vertical and extending downwards, is parallel to the rear wheel and other arm, being transversely horizontal is extending outwards away from the wheel wherein vertical arm is attached at its lower end to outer ring of coplanar ball bearing; above mentioned ball bearing is coaxially mounted on corresponding side of the hub of the rear wheel; horizontal arm of hub fastener at its ends are attached to the inner side of the lower arms of V-shaped truss mentioned in [Claim 15] and [17], on corresponding side of rear wheel over bridging rotatable part of the rear crankshaft. [Claim 19] In one possible variation of the drive mechanism claimed in [Claim 1] - [Claim 13], wherein gear ring is only peripherally pivoted, pedals are directly pivoted on the outer side of the gear ring. [Claim 20] In one possible variation of the drive mechanism claimed in [Claims 1] - [Claim 13], wherein gear ring is only axially pivoted, carrier plate at its periphery is connected to drive bracket via U-shaped pegs over-bridging gear ring. [Claim 21] As an alternative arrangement of drive mechanism, drive assembly may be positioned such that its center is higher from the ground than the center of the rear wheel. |
| AMENDED CLAIMS received by the International Bureau on 16 July 2019 (16.07.2019) [Claim 1] Bicycle with bilateral sided chainless multi-shaft multi-axis drive mechanism providing localized gear ratio and protecting rider clothing from gears comprising plurality of crankshafts at the front part, pair of crankshafts at the rear wheel and coupling shafts joining the crankpin bearings at the front and rear part in a way that crankshafts at the front, upon rotation using manual force, generate rotatary motion in the rear wheel and a novel robust rear bracket to secure the rear wheel along with rear part of drive mechanism with the frame while facilitating better bike kinematics and allowing bilateral rear suspension. [Claim 2] Chainless multi-shaft multi-axis drive mechanism, as claimed in [Claim 1], comprising front part which includes a pair of chainless drive assemblies each providing localized gear ratio and comprising plurality of integrally formed crankshafts, multipoint inter-drive-assembly-coupling mechanism, a pair of pedals, a pair of drive enclosure brackets each of which secure a drive assembly to the frame via bracket support, rear part which includes rear wheel assembly and plurality of front-rear-coupling shafts coupling the front and rear part. [Claim 3] Rear wheel assembly, as claimed in [Claim 2], comprises a wheel at the rear part of bicycle whose hub at each end is coaxially connected to flywheel shaft of a single cylinder crankshaft via a coaxial one way ratchet ball bearings with an arrangement such that outer ring or inner ring of the said ball bearing is coaxially connected to hub of the rear wheel and inner ring or outer ring respectively is connected coaxially to flywheel shaft of the said crankshaft, rotation of the crankshaft engages the wheel only to move in forward direction, crankpin bearing of crankshaft on one side is in opposite phase with respect to the crankpin bearing of crankshaft on the other side. [Claim 4] Each drive assembly, as claimed in [Claim 2], comprises of a special type of epicyclic gear which we refer as pivoted-slewing-bearing-epicyclic- gear, with plurality of integrally formed crankshafts each of whose crankpin bearing is synchronized into same phase as the crankshaft on the rear wheel on the side same as that of drive assembly. [Claim 5] Pivoted-slewing-bearing-epicyclic-gear, as claimed in [Claim 4], comprises a circular plate called as carrier plate having plurality of spur gears including planetary gears, a sun gear, satellite gears and far planet gears journalled to it and connected along its circumference to a internal toothed slewing bearing via U-shaped pegs, in arrangement such that center of sun gear is at the center of the carrier plate, carrier plate at its side containing sun gear is attached at its periphery to the outer ring of the said slewing bearing over-bridging gear ring with the help of U- shaped pegs such that slewing bearing is coaxial with Sun gear, each of planetary gears which are spur gears of equal radii is meshingly engaged with sun gear and gear ring of the slewing bearing, each satellite gear is meshingly engaged with two adjacent planetary gears and a far planet gear, each far planet gear is meshingly engaged with gear ring of the said slewing bearing and a satellite gear, and a pivot plate, which is an eared circular plate with radius equal to the average of outer and inner radius of gear ring, is attached at its rim to the gear ring at its outer side and is coaxially journalled to the outer side of the carrier plate. [Claim 6] Pivoted-slewing-bearing-epicyclic gear, described in [Claim 5], is constrained to follow the conditions that number of planetary gears, satellite gears and far planet gears used are three radius of planetary gears being greater than the radius of sun gear, satellite gears and far planet gears, radius of planetary gears are chosen such that the difference between the radius of planetary gear and internal gear ring of slewing bearing provides appropriate localized gear ratio and ease of pedaling, satellite gears are of equal radii, far planet gears are of equal radii, centers of three planetary gears forms an equilateral triangle with its circumcenter being center of sun gear, centers of satellite gears and far planet gears falls on the perpendicular bisectors of the said triangle. [Claim 7] Each of the planetary gears of pivoted-slewing-bearing-epicyclic gear, claimed in [Claim 5], has metal peg is journalled at a point on its base circle such that planetary gears can additionally function as crankshaft with metal peg functions as its crankpin bearing, crankshaft thus formed at each planetary gear need to be of radius and in a phase equal to that of rear wheel crankshaft, mentioned in [Claim 3], on the same side of the bicycle. [Claim 8] Front-rear-coupling shaft, mentioned in [Claim 2], at each side of the bicycle is a set of maximum three coplanar straight shafts having their rear ends conjoined in way that each pair of adjacent shaft make equal angle at the joining point, and have conjoined end connected to the crankpin bearing of the rear crankshaft and each front end connected to the crankpin bearing of a planetary gear. [Claim 9] Multipoint inter-drive-assembly-coupling mechanism, mentioned in [Claim 2], consists of plurality of Z-shaped shafts each of whose ends are connected to top of crankpin bearings of a pair of coaxially parallel planetary gears on the drive assemblies with its middle arm coaxial with corresponding planetary gears. [Claim 10] Drive bracket support, claimed in [Claim 2] is a vertical rectangular metal plate, coplanar with bicycle frame, is attached at its upper side to bottom end of down tube and seat tube and have ball bearings mounted on its plane each of which coaxially houses middle arm of a inter-drive-assembly-coupling shaft, described in [Claim 9] [Claim 11] Each of the pair of drive enclosure bracket, as claimed in [Claim 2], comprises an enclosure which is in the form of cylinder, with its axis being perpendicular to the frame of the bicycle, attached at its inner side rim to drive bracket support, explained in [Claim 10], vertically sliced to have a rectangular opening facing rear part of the bicycle, with cylinder being of radius equal to the outer radius of slewing bearing and length approximately equal to distance between frame and a carrier plate, with opening big enough to provide space for the motion of front- rear-coupling shafts, a circular annular plate, attached to outer side rim of the said enclosure, to which outer ring of drive assembly is fastened, and a metal bar referred to as shaft stays connecting said rear part of circular annular plate to outer end of main bearing shaft of rear crank shaft explained in claim[3]. [Claim 12] A pedal, claimed in [Claim 2] is pivoted to the periphery of the pivot plate, claimed in [Claim 5], at its outer side. [Claim 13] Carrier plates, claimed in [Claim 5], can be fixed to be stationary by directly connecting it to the drive bracket support, described in [Claim 10], via rods. [Claim 14] Rear wheel support mechanism claimed in [Claim 1], comprises rear bracket, rear bracket support and a pair of hub fasteners, one on right side of rear wheel and one on left side of rear wheel. [Claim 15] Rear bracket comprises two V-shaped planar trusses parallel to the rear wheel with one truss located on right side of rear wheel and other located on left side of rear wheel. [Claim 16] Rear bracket support, which connects upper ends of both the V-shaped planar trusses of rear bracket to the bicycle frame, comprises two forward slanting A-shaped trusses and a tube extending rearwardly from the rear end of top tube wherein one A-shaped truss located on rear side of the seat tube is connected at its angled upper end to rear side of the said tube; other truss located on front side of the seat tube is connected at its angled upper end to the top tube; bottom ends of two arms of front and rear A-shaped trusses are connected to upper front ends and upper rear ends, respectively of rear bracket; [Claim 17] Each of V-shaped planar trusses, mentioned in [Claim 15], comprises two coplanar V-shaped rods arranged one behind the other parallel to the rear wheel and a V- shaped peg located on corresponding side of the rear wheel wherein each of V-shaped rods have acute angle bend facing the forward direction; angled corners of V-shaped rods lies on the upper rear side of axle of the rear wheel; angled corner of front side V-shaped rod is located vertically higher than that of rear side V-shaped rod; each of V-shaped rods have one arm extending downwards with their bottom ends fixedly connected to the main bearing shaft of the rear crank shaft on the corresponding side of the rear wheel; above mentioned downward extending rods may be suspension rod according to requirement thus forming bilateral rear wheel suspension; upper ends of rear and front V-shaped trusses are connected to bottom ends of corresponding side arms of rear and front A-shaped trusses respectively; V-shaped peg is attached at its angled corner to the angled corner of front side V- shaped rod at its rearward side and one arm as a rearward extension of lower arm of front side V-shaped rod with its upper end attached to upper arm of rear side V-shaped rod and other arm as a rearward extension of upper arm of front V-shaped rod with its lower end attached to lower arm of rear side V-shaped rod. [Claim 18] Each of hub fasteners, mentioned in [Claim 14], is right-angled metal strip with one arm, being vertical and extending downwards, is parallel to the rear wheel and other arm, being transversely horizontal is extending outwards away from the wheel wherein vertical arm is attached at its lower end to outer ring of coplanar ball bearing; above mentioned ball bearing is coaxially mounted on corresponding side of the hub of the rear wheel; horizontal arm of hub fastener at its ends are attached to the inner side of the lower arms of V-shaped truss mentioned in [Claim 15] and [17], on corresponding side of rear wheel over bridging rotatable part of the rear crankshaft. [Claim 19] In one possible variation of the drive mechanism claimed in [Claim 1] - [Claim 13], wherein gear ring is only peripherally pivoted, pedals are directly pivoted on the outer side of the gear ring. [Claim 20] In one possible variation of the drive mechanism claimed in [Claims 1] - [Claim 13], wherein gear ring is only axially pivoted, carrier plate at its periphery is connected to drive bracket via U-shaped pegs over-bridging gear ring. [Claim 21] As an alternative arrangement of drive mechanism, drive assembly may be positioned such that its center is higher from the ground than the center of the rear wheel. |
Field of Invention
[01] The present disclosure relates generally to a shaft driven chainless drive mechanism and robust rear wheel support mechanism for a bicycle, and more particularly, to a drive mechanism capable of employing 1, 2, 3, 4, 5 or 6 shafts and rear wheel support mechanism for a bicycle which in addition to securing rear wheel to the frame can also facilitate better bike kinematics.
Background of Invention
[02] Typically, bicycles with chainless shaft drive mechanism consist of bevel pinion force transmission mechanism. Pedal is used to rotate a bevel gear which in turn rotates pinion gear attached to front part of the shaft. Pinion gear attached to rear end of the rotating shaft rotates bevel gear attached to hub of rear wheel.
Technical Problem
[03] There is significant amount of loss of energy during power transfer from bevel to pinion gear.
[04] In the prior art it is impossible to use multiple shafts for force transmission to allow the application of manual force on larger area.
[05] In the prior art, chainless shaft driven bicycles have only one point coupling between the left side and the right side of the drive mechanism, that is, through the spindle housed in bottom bracket.
[06] In the prior art frame of chainless shaft driven bicycle comprises of paired seat stays to secure the rear wheel. The seat stays are forward slanted due to which it impedes the forward movement of bicycle.
Summary of Invention [07] One of the objectives is to provide bilateral sided drive mechanism to make maximum utilization of manual force on both sides of the bicycle. Drive mechanism consists of two force transmission mechanisms, one on each side of the bicycle.
[08] One of the objectives is to employ chainless force transmission mechanism without using bevel-pinion gear mechanism and prevent the loss of manual force while transmission of force from front drive assembly to rear wheel.
Drive assembly located on front side comprises of crankshafts which is enabled to rotate the crankshaft attached to the rear wheel with the help of front-rear-coupling shafts, resulting in the rotation of the rear wheel.
[09] One of the objectives is to allow the ease of use provided by conventional bicycle that is drive mechanism allow the application of manual force via pedals rotation about fixed center and also provide the mechanism to facilitate the application of manual force on larger area.
This objective is achieved due to a feature of the drive assembly which facilitates rider to rotate the crankshafts in the drive assembly by the rotation of pedals.
This feature is accomplished by employing pivoted-slewing-bearing-epicyclic gear a special type of planetary gear box, crankshafts, and a pedal in each drive assembly. Z- shaped rods connecting coaxially parallel planetary gears in the drive assemblies on two sides forms crankshaft on the front side and rotatary forces generated is transmitted to the rear wheel through coupling shafts.
[10] One of the objectives in this force transmission mechanism is to provide localized gear ratio which is achieved by the difference in radius of gear ring and planetary gear.
[11] One of the objectives is to conceal drive mechanism from the riders clothing.
Drive assemblies in the drive mechanism according to this invention is enclosed between the pair of carrier plates/pivot plates and drive enclosure brackets and therefore do not come in contact with the clothing of the rider
[12] One of the objectives is to achieve the driving efficiency comparable to chain driven bicycle without using chain.
This objective is achieved due to a feature of drive assembly of this invention which maximizes the number of tooth of gear ring gear that is used to rotate the planetary gears. This feature is accomplished by appropriately journalling additional gears, apart from planetary and sun gears, to the carrier plate. These additional gears are classified in two categories, one is refered in this patent as satellite gears and the other as far planet gears. Far planetary gears, spur gears of smaller size as compared to planetary gears, are meshingly engaged with gear ring and their sole purpose is to provide additional rotatory force to planetary gears via satellite gears. Satellite gears are meshingly engaged with two adjacent planetary gears and a far planet gears. With this feature loss of manual force is further minimized and efficiency of chain driven drive mechanism is achieved without using chain.
[13] One of the various objectives achieved by pivoted-slewing-bearing-epicyclic gear
mounted with crankshaft is to allow the application of driving force over a larger area by multiple axis to help in high speed and torque setups.
[14] One of the various objectives is to provide multipoint coupling mechanism between the drive assemblies on the left and right side of the bicycle to improve the efficiency of drive mechanism.
In order to achieve this objective crankpin bearing of the planetary gear of drive assembly on left side of the bicycle is coupled to crankpin bearing of the coaxial planetary gear on the drive assembly located on the right side of the bicycle via Z-shaped rods. We use Z-shaped shaft because we require rear crankshaft on the left side to be opposite phase to that of the rear crankshaft on the right side of the bicycle. For this we need the crankpin bearing of the coupled planetary gear to be in the opposite phase.
[15] One of the various objectives is to provide robust wheel support system which, in
addition to secure the rear wheel, should facilitate better bike kinematics.
We achieve this by replacing seat stay tube of conventional bicycle by robust wheel support mechanism consisting of rear bracket arranged in special orientation.
Rear bracket is a pair of V-shaped planar trusses, which holds the rear wheel at four points of contact, is attached to the rear part of top tube via rear bracket support with the help of a pair of A-shaped trusses. Rear bracket has four dropouts at its bottom, two on each side of the wheel.
Dropouts on outer side are connected to the main bearing shaft of the crankshafts securing axis of rotation to the crank shaft. Each of the pair of planar trusses is attached on the inner side to outer ring of ball bearing which coaxially holds the hub of the rear wheel via L-shaped angle bracket over-bridging the rotatable part of the crankshaft. Inner side dropouts help to share the load on the crank pin of the rear crank shaft from main bearing shaft of crankshaft to the hub of the wheel. Lower section of each of the planar trusses along with L-shaped angle bracket of the rear bracket where it is connected to the wheel is slanted backwards for better bicycle kinematics. With backward slanting, weight of the rider is utilized to push the wheel in forward direction. Contrarily with forward slanting, conventional seat stay tube pushes the wheel in backward direction due to the weight of the rider.
[16] One of the various objectives is to provide axial support to inter-drive assembly coupling shaft which in our case is Z-shaped rod.
This objective is achieved via bracket support. Bracket support is rectangular plate positioned along the plane of the bicycle frame. Its upper side is connected to bottom ends of seat tube and down tube. Lower half is attached to bracket encasing drive assembly. The bracket support has ball bearing attached on its plane through which said Z-shaped rod passes through.
[17] This transmission mechanism allows the option to choose the number of shafts from one to six according to the requirement. Except for the spread of force to large area all other advantages will be retained.
Brief Description of Drawings
[18] [Fig. 1] Oblique view of the preferred embodiment of a shaft driven bicycle integrated with robust rear wheel support mechanism, according to this invention.
[19] [Fig. 2] Side view of the bicycle according to this invention
[20] [Fig. 3] Perspective view of drive system
[21] [Fig. 4] Perspective view of drive system enclosed in drive enclosure bracket
[22] [Fig. 5] Front view of one side of drive system
[23] [Fig. 6] and [Fig. 7] Front view and exploded view of back side of pivoted-slewing- bearing-epicyclic gear
[24] [Fig. 8] Z-shape inter-drive coupling rods
[25] [Fig. 9] Drive enclosure bracket with bracket support and shaft stays [29] [Fig. 10] Rear wheel assembly with rear wheel support mechanism. [29] [Fig. 11] and [Fig. 12] Rear wheel with crankshaft and rear wheel support mechanism respectively
[30] [Fig. 13] Rear wheel crank shaft attached with one way rachet ball bearing
[26] [Fig. 14] Variation of the drive system wherein gear ring is only peripherally pivoted
[27] [Fig. 15] Variation of the drive system wherein gear ring is only axially pivoted
[31] [Fig. 16], [Fig. 17], [Fig. 18], [Fig. 19], [Fig. 20], [Fig. 21] Explanation of the drive kinematics of one side of drive system through schematic diagrams.
[32] [Fig. 22], [Fig. 23] Explanation of efficiency enhancement due to inter-drive coupling rods on the drive kinematics of drive mechanism through schematic diagrams.
[33] [Fig. 24] Impact of weight of rider on rear wheel via rear wheel support mechanism.
[34] [Fig. 25] Schematic diagram of an alternative arrangement of drive system for facilitating greater ground clearance.
Description of Embodiments
[35] Referring to [FIG. 1], the preferred embodiment of a bicycle (1) according to this
invention is shown to include a frame consisting of head tube (HT) , seat tube (ST), down tube (DT), top tube (TT), Drive Bracket Support (DBS), Drive Bracket (DB), shaft stays (SST), Drive system (DS), Pedal (PDL), Rear wheel assembly (RWA), Rear wheel support mechanism (RWSM) consisting of Rear Bracket Support (RBS) and Rear Bracket (RB) .
Frame
[36] As shown in [Fig. 1] this bicycle (1) has frame similar to conventional bicycle. It is a planar truss consisting of a front triangle and the rear parallelogram.
[37] The front triangle consists of the head tube (HT), seat tube (ST) down tube (DT) top tube (TT) and Bracket at the bottom to hold drive assembly. The top tube (TT) connects the head tube (HT) to the seat tube (ST) at the top. Top of down tube (DT) is attached to head tube (HT).
Bottom end of seat tube (ST) and down tube (DT) is attached to bracket support (DBS). Bracket (DB) securing drive assembly is connected to frame via bracket support (DBS). [38] The rear parallelogram consists of the seat tube and paired shaft stays (SST) and Rear Bracket Support (RBS), Rear Bracket (RB).
Rear bracket support rod (RBS) comprises an horizontal rod (RBS2) which is a rearward extension of top tube (TT) and two A-shaped trusses, one (RBS1) in rear side of seat attached at mid joint to rear end of horizontal rod (RBS2) making an acute angle with it along the rear side, and other (RBS3) in front side of seat attached at its mid joint to top tube (TT) making an acute angle with it along the rear side.
Shaft stays (SST), a metal bar, is at one end connected to left and right end of rear wheel assembly (RWA), running parallel to the shaft and are fixedly connected to the bracket at the other end.
Drive System
[39] As shown in Fig. 3 Drive system (DS) consists of a pair of coupled drive assemblies (DA) in the front, one on each side of the bicycle, rear wheel assembly (RWA) and plurality of front-rear-coupling mechanism (DCS) and pair of pedals (PDL).
[40] Number of shafts can be one to six according to user requirement. For illustration we have shown six shafts. Two drive assemblies are coupled via inter-drive-assembly- coupling shafts (CPL) shown in Fig 5 a to improve their efficiency.
Drive assembly
[41] Drive assembly (DA), as shown in [Fig. 3] and 5, comprises of a special type of epicyclic gear which we refer as pivoted-slewing-bearing-epicyclic-gear (SBE), integrally formed crankshafts and a pedal (PDL).
Pivoted-Slewing-Bearing-Epicyclic gear
[42] As shown in [Fig. 6] and [Fig. 7] pivoted-slewing-bearing-epicyclic-gear comprises of a circular plate called as carrier plate (CP) and plurality of planetary gears (Pl), (P2), (P3), a sun gear (Sl), plurality of satellite gears, (Satl), (Sat2), (Sat3) plurality of far planet gears, (FP1) (FP2) (FP3) internal-toothed slewing bearing (ISB) and U-shaped pegs (UPG), straight metal pegs (PPG) and an eared circular plate (PIV).
Internal toothed slewing bearing (ISB) consist of an internal gear ring (SGR) with internal toothing coaxially mounted on external ring (SOR) and an integrated raceway system rolling elements - balls or cylindrical rollers - that are separated by spacers. In slewing bearing, internal gear ring (SGR) can rotate with outer ring (SOR) fixed along a fixed axis, whilst guaranteeing the axial and radial link between the two parts.
Outer ring (SOR) is preferably flanged.
Three planetary spur gear (Pl), (P2), (P3), sun gear (Sl), three satellite gears (Satl), (Sat2), (Sat3) and three far planet gears (FP1), (FP2), (FP3) are journalled to the carrier plate (CP) in an arrangement as explained below.
Sun gear (Sl) which is a spur gear is journaled to the center of the carrier plate (CP). Planetary gears (Px) are spur gears of equal radii, and journalled to carrier plate (CP) such that each of them is me shingly engaged with sun gear (Sl) and gear ring (SGR) of the slewing bearing. Centers of planetary gears form an equilateral triangle.
Each satellite gear (Satx) which is a spur gear with radius smaller than that of planetary gears is journalled to the carrier plate such that it is meshingly engaged with two adjacent planetary gears and a far planet gear.
Centers of satellite gear form an equilateral triangle.
Each far planet gear (FP1), (FP2), (FP3) which is a spur gear with radius smaller than that of planetary gears is journalled to the carrier plate such that it is meshingly engaged with gear ring of the said slewing bearing and a satellite gear.
Carrier plate (CP) at its inner side, containing sun gear (Sl), is attached at its periphery to the outer ring (SOR) of the said slewing bearing over-bridging gear ring (SGR) with the help of EG-shaped pegs (EIPG) such that slewing bearing is coaxial with Sun gear (Sl).
As shown in [Fig. 7], an eared circular plate (PIV) called as pivot plate, coaxially journalled to outer side of the carrier plate via ball bearing (PIVB), is attached at its rim to the outer side of gear ring (SGR).
Drive assembly input and output
[43] As shown in [Fig. 5] a metal peg (PPG) is journalled at a point on the perimeter of the face of each planetary gear of the drive assembly, so that planetary gears can additionally function as crank shaft. Metal peg functions as the crankpin bearing for the
corresponding planetary gear. Crankshafts thus formed at planetary gears are of equal radii.
[44] As shown in [Fig. 3] a pedal (PDL) A pedal is attached at the periphery on the outer side of the pivot plate (PIV).
Internal gear ring (SGR) act as input point and metal pegs (PPG) connected to planetary gears act as output points of front drive assembly. Rear wheel assembly
[45] Rear wheel assembly (RWA) is illsutrated with the help of [Fig. 10] and [Fig. 13] Rear wheel assembly (RWA) comprises a wheel (RW) with hub, pair of one way ratchet ball bearing (RWB) and a pair of single cylinder crankshafts (RWC).
Hub of the rear wheel at each of its ends is coaxially connected to the outer ring of a one way ratchet wheel (RWB).
Flywheel shaft (RWC1) of crank shaft (RWC) of rear wheel is coaxially connected to the inner ring of ball bearing RWB.
Main bearing shaft (RWC2) of each crankshaft (RWC) is connected to the frame via rear bracket (RB) and rear bracket support (RBS).
Force Transmission Coupling Shafts
[46] As shown in Fig 5 drive mechanism, on each side, consists of set of three shafts (DCS) conjoined at one end to form a coplanar fork like structure in such a way that angles formed by adjacent pairs of shafts are equal.
Front end of each shaft is connected to crankpin (PPG) journalled to a planetary gear. Conjoined rear end of the coupling shafts (DCS) is connected to crankpin bearing RWC3 of rear wheel crankshaft (RWC).
As is evident in this transmission mechanism we have the option to use 1, 2, 3, 4, 5 or 6 shafts. With usage of lesser number of shafts, except for the spread of force to large area all other advantages will be retained.
Multipoint inter-drive-assembly coupling
[47] Pair of coaxially parallel drive assemblies (DA) are coupled via Z-shaped shafts (CPL).
As shown in [Fig. 5] crankpin bearing (PPG) on the planetary gear of left side drive assembly at its top is connected to crankpin bearing (PPG) of the coaxially parallel planetary gear on the right side drive assembly via Z-shaped shafts (CPL) in manner that middle arm of the shafts (CPL) are coaxial with the respective pair of coaxially parallel planetary gears.
[48] We use Z-shaped shafts because we require rear crankshaft on the left side to be opposite phase to that of the rear crankshaft on the right side of the bicycle. For this we need the crankpin bearing of the coupled planetary gear to be in the opposite phase.
Relative positioning of the crankshafts [49] Radius of crankshafts formed by planetary gears are equal to the radius of crankshaft at the corresponding side of the rear wheel.
The length of the shafts in coupling mechanism (DCM) is such that all the crankshaft on each side of the bicycle is at same phase as shown in the [Fig. 5] With inter-drive assembly rods as Z-shaped shafts, it is assured that the the two crank shafts attached to the ends of hub of rear wheel are opposite phase with respect to each other.
Drive Enclosure Bracket
[50] As shown in Fig. 1 two drive assemblies (DA), are secured to the frame at its bottom of front triangle by a pair of drive enclosure brackets (DB) in a position so that they are coaxially parallel to each other and are at equal distance from the plane of the bicycle. Keeping the outer ring (SOR) fixed is necessary for the functioning of drive mechanism.
[51] As shown in [Fig. 9] drive enclosure bracket (DB), comprises of an enclosure (BCL) which is in the form of cylinder vertically sliced to have a rectangular opening at a required distance from the center, with cylinder being of radius equal to the outer radius of slewing bearing and length appproximately equal to half the length of inter-drive coupling shafts. Opening is to provide space for the motion of drive coupling shafts (DCS). Enclosure (BCL) is attached at its rim on one side to the bracket support such that rectangular opening is facing the rear side of the bicycle. Rim on the other side of the enclosure is attached coaxially to a circular annular plate (BCA).
Cylindrical enclosure (BCL) of the two drive assemblies are coaxially parallel with each other. Outer ring (SOR) of drive assemly (DA) is fastened to (BCA).
Drive Braket support (DBS) is a rectangular plate attached to the bottom ends of down tube (DT) and seat tube (ST). It has ball bearings (DBB), shown in Fig.8, on its plane on which inter-drive assemblies coupling rods (CPL) are axially mounted.
Note that carrier plates can be fixed to be stationary by directly attaching it to the frame in
variety of ways. For example, it can be fixedly connected to the Drive Bracket Support (DBS).
Rear Wheel Support Mechanism
[52] Since crankshafts, instead of wheel axle, are attached to hub of the rear wheel, securing the rear wheel assembly to the frame in a robust manner is a challenge. As shown in Fig. 1, [Fig. 10] and [Fig. 12] robust rear wheel support mechanism (RWSM) comprises rear bracket (RB), rear bracket support (RBS) and a pair of hub fasteners, one (RHF) on right side of rear wheel and one (LHF) on left side of rear wheel. It secures the rear wheel in robust manner and additionally facilitates better bike kinematics.
[53] As shown in Fig. 1, [Fig. 10] and [Fig. 12], rear bracket (RB) comprises two V-shaped planar trusses parallel to the rear wheel with one truss (RRB) located on right side of rear wheel and other (LRB) located on left side of rear wheel.
[54] As shown in Fig. 1, [Fig. 10] and [Fig. 12], rear bracket support (RBS) connects upper ends of both the trusses of rear bracket to the bicycle frame.
Rear bracket support (RBS) comprises two forward slanting A-shaped trusses (RBS1) and (RBS3) and a tube (RBS2) extending rearwardly from the rear end of top tube (TT). One A-shaped truss (RBS1) located on rear side of the seat tube is connected at its angled upper end to rear side of the tube (RBS2) and other truss (RBS3) located on front side of the seat tube is connected at its angled upper end to the top tube (TT). Bottom ends of two arms of A-shaped truss (RBS3) and (RBS1) are connected to upper front ends and upper rear ends, respectively of V-shaped trusses (RRB) and (LRB).
[55] As shown in [Fig. 1], [Fig. 10] and [Fig. 12], V-shaped planar truss (RRB) comprises two coplanar V-shaped rods (RRB1) and (RRB2) and a V-shaped peg (RRB3). V-shaped planar truss (RRB) is configured such that each of V-shaped rods (RRB1) and (RRB2) have acute angle bend facing the forward direction; V-shaped rod (RRB1) lies on the rear side of V-shaped rod (RRB2); angled corners of V-shaped rods (RRB1) and (RRB2) lies on the upper rear side of axle of the rear wheel; angled corner of V-shaped rod (RRB1) is located vertically higher than that of V-shaped rod (RRB2); each of V-shaped rods (RRB1) and (RRB2) have one arm extending downwards with their bottom ends fixedly connected to the main bearing shaft (RWC2) of the rear crank shaft on the right side of the rear wheel (RW); upper ends of V-shaped trusses (RRB1) and (RRB2) are connected to bottom ends of right arms of A-shaped trusses trusses (RBS1) and (RBS3)
respectively; V-shaped peg (RRB3) is attached at its angled corner to the angled corner of front side V-shaped rod (RRB2) at its rearward side and one arm as a rearward extension of lower arm of V-shaped rod (RRB2) with its upper end attached to upper arm of rear V-shaped rod (RRB1) and other arm as a rearward extension of upper arm of front V-shaped rod (RRB2) with its lower end attached to lower arm of rear V-shaped rod (RRB1). [56] As shown in [Fig. 1], [Fig. 10] and [Fig. 12], V-shaped planar truss (LRB) comprises two coplanar V-shaped rods (LRB1) and (LRB2) and a V-shaped peg (LRB3). V-shaped planar truss (LRB) is configured such that each of V-shaped rods (LRB1) and (LRB2) have acute angle bend facing the forward direction; V-shaped rod (LRB1) lies on the rear side of V-shaped rod (LRB2); angled corners of V-shaped rods (LRB1) and (LRB2) lies on the upper rear side of axle of the rear wheel; angled corners of V-shaped rods (LRB1) and (LRB2) lies on the upper rear side of axle of the rear wheel; each of V-shaped rods (LRB1) and (LRB2) have one arm extending downwards with their bottom ends fixedly connected to the main bearing shaft (RWC2) of the rear crank shaft on the left side of the rear wheel (RW); upper ends of V-shaped trusses (LRB1) and (LRB2) are connected to bottom ends of left arms of A-shaped trusses (RBS1) and (RBS3) respectively; V-shaped peg (RRB3) is attached at its angled corner to the angled corner of front side V-shaped rod (RRB2) at its rearward side and one arm as a rearward extension of lower arm of V- shaped rod (RRB2) with its upper end attached to upper arm of rear V-shaped rod (RRB1) and other arm as a rearward extension of upper arm of front V-shaped rod (RRB2) with its lower end attached to lower arm of rear V-shaped rod (RRB1).
[57] As shown in [Fig. 1], [Fig. 10] and [Fig. 12], parallel trusses (RRB) and (LRB) thus being connected to the main bearing shaft (RWC2) of the rear crank shaft secure the wheel to the frame and provides axis of rotation to the crank shaft. Still the problem is that a significant part of load of bicycle is on crankpin of rear crank shaft which is solved using hub fasteners (RHF) and (LHF).
[58] As shown in [Fig. 1], [Fig. 10] and [Fig. 12], each of hub fasteners (RHF) and (LHF) is right-angled metal strip with one arm, being vertical and extending downwards, is parallel to the rear wheel and other arm, being transversely horizontal is extending outwards away from the wheel.
[59] As shown in [Fig. 1], [Fig. 10] and [Fig. 12], each of hub fasteners (RHF) and (LHF) is attached at lower end of its vertical arm to outer ring of ball bearing coplanar to the said vertical arm of the right-angled metal strip.
Ball bearings of each of hub fasteners (RHF) and (LHF) are coaxially mounted on right and left side, respectively, of the hub of the rear wheel (RW). Horizontal arm of hub fasteners (RHF) and (LHF) at its ends are attached to the inner side of the lower arms of V-shaped trusses (RRB) and (LRB), respectively, over bridging rotatable part of the rear crankshaft (RWC).
Hub fasteners provide additional support to the wheel from the frame and also share a significant amount of load of bicycle from the crankpin of the rear crankshaft.
Variations of Drive Mechanism
[60] In one possible variation of the drive mechanism, wherein there is no pivot plate and gear ring is only peripherally pivoted, pedals are directly pivoted on the outer side of the gear ring (SGR) as shown in [Fig. 14]
[61] In one possible variation of the drive mechanism, wherein gear ring is not part of slewing bearing and is only axially pivoted at its center to carrier plate (CP) and carrier plate at its periphery is connected to drive bracket (DB) via U-shaped pegs (UPG) as shown in [Fig. 15]
Drive operation of drive assembly
[62] Internal gear ring (SGR) functions as the input from manual force to the drive assemblies with the help of pedals. As shown in [Fig. 16] whenever gear ring (SGR) is rotated all the planetary gears rotate and therefore crankpin bearings (PPG) in the same direction.
Analysis of manual force transmission on drive mechanism on one side
[63] Analytical explanation of manual force transmission on drive mechanism on one side of the bicycle is illustrated in schematic diagrams in [Fig. 17], [Fig. 18], [Fig. 19], [Fig. 20] and [Fig. 21] Crankpin bearings of top, middle, bottom planetary gear and crankpin bearing of rear crankshaft are denoted as A, B, C and D respectively. Center of rotation of crankpin bearing of rear crankshaft is denoted by E. When rotating force is applied on ring gear (SGR) via pedal each coupling shaft experiences equal force F along tangential direction of the planetary gear to which they are connected via crankpin bearing (PPG). Let Fi, F 2 and F 3 F ± , F 2 and F 3 denote the force applied along the top, middle and bottom coupling shafts respectively. From the schematic diagram in [Fig. 19] we see that
| Fi| = |F| cos(90 - alpha + theta) = |F| sin(alpha - theta). Similarly | F 2 | = |F| sin(alpha) and | F 3 | = |F| sin(alpha + theta).
Let resultant rotating force applied to the rear crank shaft denoted as F r F r . Then from the diagram in [Fig. 20] we see that | F r | = |F| sin(alpha - theta) + |F| sin(alpha) + |F| sin(alpha + theta) = 0.5*|F| (3 - cos(2*alpha))*(l+2*cos(2*theta)). For alpha = Pi/2 and - Pi/2, | F r | attains maximum value equal to 2*|F|*(l + 2*cos(2*theta)). For alpha between -(Pi - theta) and (-theta), that is upper shadow region shown in [Fig. 21], all three coupling rods are in push mode at the crank shaft. For alpha between -theta and (Pi + theta), that is upper shadow region shown in [Fig. 21], at least one of three coupling rods are in pull mode at the rear crank shaft. When one side drive is in push mode then other side drive assembly is in pull mode region.
Effect of multipoint inter-drive coupling
[64] Effect of coupling between two drive assemblies via Z-shaped shafts (CPL) is explained in schematic diagrams in [Fig. 22] and [Fig. 23] For ease of explanation we denote drive assembly on left side as DAL and right side as DAR. We exert maximum rotating force when pedal is making angle Pi/2 to -Pi/2, shown as shadowed region in [Fig. 23], with the horizontal, that is, while pedaling from top to bottom in clockwise direction. For angle between Pi/2 to theta, shown as upper shadowed region in [Fig. 23], drive assembly DAL is in pull region where as it exerts push motion in the drive assembly DAR. For angle between theta to -theta, shown as intersection of upper and lower shadowed region in [Fig. 17], drive assembly DAL is in pull region and it exerts pull motion in the drive assembly DAR via coupling between drive assemblies. For angle between theta to -Pi/2, shown as lower shadowed region in [Fig. 23], drive assembly DAL is in push region and it exerts pull motion in the drive assembly DAR via coupling between drive assemblies. Pedaling the drive assembly DAR exerts the similar driving force on DAR side as well as DAL side. Thus part of the pull region on side DAL from Pi/2 to theta has pedal impact from side DAL whereas from (Pi + theta) to Pi/2 has pedal impact from side DAR.
Similarly vice versa. Thus there is no idle time at the rear crank.
Impact of Rear Wheel Support Mechanism
[65] Let W1 be the force, due to weight W of the rider, acting along the plane of lower arm of rear bracket. As shown in the [Fig. 24] horizontal component of this force Wl H is in the direction of the motion of the bicycle.
Alternative arrangement of drive mechanism
[66] In order to have better ground clearance for pedaling, drive assembly may be positioned higher from the ground as shown in [Fig. 25], so that the line joining the center of rear crank and drive assembly makes an angle gamma with the horizontal. Kinematic analyses, discussed above, is valid for this by replacing alpha with (alpha - gamma).