Title of Invention

A SCOOTER HAVING A CENTRALLY MOUNTED ENGINE WITH AN ALL GEAR TRANSMISSION MEANS

Abstract

Having a mentally mounted engine with an all gear mission means, wherein said gear transmission means is operatively connected between the crankshaft of said engine and the drive gear variable speed ratio gear box, the rear wheel of said scooter is mounted on the output shaft of said gear box, the axes of the shaft(s) of said gear transmission means and the input and output shafts of said gearbox are lying in a plane slightly inclined with respect to the horizontal plane the cylinder-axis of said engine is slightly inclined upwardly to said inched plane so as to give sufficient ground clearance, the protruding ends of both said engine crankshaft and gear box output shaft being mutually opposite to each other along their axes, both said gear transmission means and said gear box being located laterally on one side of said rear wheel or the longitudinal central plane, the perpendicular distance between the axes of said engine-crankshaft and rear wheel being minimal and sufficient enough to maintain a radial clearance between said rear wheel and the crankcase of said engine, the perpendicular distance between said engine-cylinder-axis and the longitudinal central plane being small and enough to maintain sufficient axial clearance between said rear wheel and the assembly of said both gear transmission means and gear box, and the distance of centre of gravity of said scooter from both the longitudinal central plane and the ground plane as well as the longitudinal distance of centre of gravity of said scooter from its front wheel axis are minimal.

Full Text

This invention relates to a scooter having a centrally mounted engine with an all gear transmission means. As known, in conventional scooters, the engine is mounted on one side of the rear-wheel, generally the right side thereof, and it is operatively connected to the rear-wheel for driving the same. This causes the position of the centre of gravity of the scooter being far away from its longitudinal central plane along its transverse-axis. This causes many problems. For instance, there will be difficulties in balancing while handling these scooters from on-stand into off-stand positions. When the rear-wheel is suddenly locked by a sudden brake while at high speeds, there are possibilities of the skidding of the rear wheel or the tendency thereof, since the moment of the couple about the yawing axis is more due to the transverse distance between the centre of gravity of the scooter and the longitudinal central plane being more and due to both the road-drag acting on the wheels in backward-direction and the forward inertia-vector of the scooter passing through its centre of gravity. Hence, it is a bit dangerous for locking the rear-wheel of conventional scooters under high-speeds. Also, the mounting arrangement of the engine with the gear-transmission means in conventional scooters has an inherent draw back in that, it has lower stability, particularly about the transverse axis at higher acceleration and deceleration values. since the centre of gravity of the scooter is at a high location from the ground plane. Moreover, since the centre of gravity of the scooter is located nearer to the rear wheel, there is also less longitudinal stability (i.e., a tendency of front-wheel take-off) under higher acceleration conditions. Furthermore, in certain other scooters, the engine is mounted centrally like in motorcycles, but the drive is transmitted through either chain or belt. It has certain inherent problems such as, wearing-out of the sprocket-teeth, chain-link or both, slackening of the chain under load, chain-slip over the sprocket-teeth (after worn-out), more maintenance, more noise, lower life-span between successive failures or belt slackness, belt replacement and the like. An object of this invention is to provide a scooter having a centrally mounted engine with an all gear transmission means so as to minimize the skidding nature even when its rear wheel is locked. Another object of this invention is to safely improve or increase the acceleration limit of scooters. A further object of this invention is to safely improve or increase the deceleration limit of scooters. With these and other objects in view, the present invention provides a scooter having a centrally mounted engine with an all gear transmission means, wherein said gear transmission means is operatively connected between the crankshaft of said engine and the drive gear of a variable speed ratio gear box, the rear wheel of said scooter is mounted on the output shaft of said gear box, the axes of the shaft(s) of said gear transmission means and the input and output shafts of said gearbox are lying in a plane slightly inclined with respect to the horizontal plane, the cylinder-axis of said engine is slightly inclined upwardly to said inclined plane so as to give sufficient ground clearance, the protruding ends of both said engine crankshaft and gear box output shaft being mutually opposite to each other along their axes, both said gear transmission means and said gear box being located laterally on one side of said rear wheel or the longitudinal central plane, the perpendicular distance between the axes of said engine-crankshaft and rear wheel being minimal and sufficient enough to maintain a radial clearance between said rear wheel and the crankcase of said engine, the perpendicular distance between said engine-cylinder-axis and the longitudinal central plane being small and enough to maintain sufficient axial clearance between said rear wheel and the assembly of said both gear transmission means and gear box, and the distance of centre of gravity of said scooter from both the longitudinal central plane and the ground plane as well as the longitudinal distance of centre of gravity of said scooter from its front wheel axis are minimal. The invention will now be apparent from the following non-limitative description with reference to the accompanying drawings, in which: FIGURE 1 shows a schematic pictorial view of an assembly of a centrally mounted engine and all gear transmission means with the rear wheel of a scooter according to this invention; FIGURE 2 shows a pictorial view of the arrangement shown in FIGURE 1 in detail; FIGURES 3 and 4 show, respectively an elevational view and a plan view of a scooter according to an embodiment of the present invention; FIGURE 5 shows a sectional top view of a constructional example of a preferred embodiment of the assembly shown in FIGURES 1 and 2; FIGURES 6&7 show, respectively an elevational view and a plan view of what is shown in FIGURE 5. Referring to the drawings, engine 1 is connected to the scooter through a toggle Hnk 5 between the front and rear wheels and preferably on or near the longitudinal central plane as shown in FIGURES 3 &4. The axis of rotation of crankshaft 1(A) of said engine 1 may be parallel to that of said rear wheel 4. An all gear transmission means 2 is located laterally on one side of the rear wheel 4 and is also operatively connected between one end of said crank shaft 1(A) of engine 1 and a variable speed ratio gear box 3. The said gear box 3 is in turn operatively connected to rear wheel 4 for causing engagement between engine 1 and rear wheel 4 to impart motion from engine 1 to rear wheel 4 through both the gear transmission means 2 and gear box 3. The gearbox 3 is located on the same side of gear transmission means 2. Unlike the conventional scooters, in the scooter according to this invention the axes of all the shafts of the gear transmission means 2 and gearbox 3 are lying in a plane inclined downward towards the rear wheel with respect to the horizontal plane and the angle of said inclination is small so that the centre of gravity of the scooter is brought down to a lower location with respect to the ground plane. Further, as shown in Figure 2, the gear transmission means 2 (see Figure 1) comprises a multi plate friction disk clutch 1(D) serially connected to a kick starter assembly 2(C). A driven gear 1(C) and a drive gear 2(A) are provided to form a reverted gear train so as to be connected together through the clutch assembly 1(D). The driven gear 1(C) is operatively connected to the driving plate of said clutch assembly 1(D) and is driven by a drive gear 1(B). The drive gear 1(B) is rigidly connected to the protruding end of the crankshaft 1(A) of engine 1. The drive gear 2(A) is to drive an idler gear 2(B) loosely mounted on a kick starter shaft 2(F) (see Figure 5). The gear 2 (B) is intum to drive an input cluster gear 3(A) of the gearbox 3. The rear wheel 4 is rigidly and detachably mounted on the protruding end 4 (A) of the output shaft 3 (B) of gearbox 3. As the engine is located at or near the centre of the scooter, the transverse distance of its centre of gravity from its longitudinal central plane is minimized. It also minimizes the longitudinal distance of the centre of gravity from its front wheel axis. Furthermore, referring to FIGURES 5 to 7, the axes of engine crank shaft 1(A), the clutch-shaft 2(A) and the kick-starter-shaft 2(F), are lying in the inclined plane mentioned hereinabove so as to provide enough radial clearance between the crankcase of engine 1 and rear wheel 4. The clutch assembly 1(D), kick-starter assembly and the gearbox 3 are all enclosed in a single cover comprising two halves 5(A) and 5(B). The part 5(A) is detachably fitted over the part 5(B) which forms a part of crankcase of the engine 1, thereby providing good accessibility to all transmission parts, by removing only one half of the cover, namely, part 5 (A). Moreover, the above said single-cover arrangement [5(A) and 5(B)] enables utilization of a common oil sump for lubrication. Thus, the maintenance, refilling of the lubricating oil and the like are made easier. The idler gear 2(B) is compounded with a ratchet gear 2(D), which is to be driven by another ratchet gear 2(E) being co-axial to the former 2(D) and also being secured against rotation with respect to the kick-starter 2(C). The assembly of ratchet gear 2(E) with kick-starter 2(C) is loaded in any known manner, for example by using a torsional spring. Furthermore, the idler gear 2(B) is constantly meshing with one of the input cluster gears 3(A) of gearbox 3. The follower 3(D) of each cluster gear 3(A), is loosely mounted on the output shaft 3(B) of the gearbox 3. The followers 3(D) also form reverted gear train(s) to each other so as to be free to rotate at different speeds with respect to each other. Any one of the followers 3 (D) is also enable to be angularly secured with the output shaft 3(B) against rotation with respect to each other by using a cross-shaped key 3(E). The cross-shaped key 3(E) is further rotatably connected to a pin 3(F) being controlled by any known gear shifting mechanism. The cross-shaped key 3(E) is axially movably connected inside of the output hollow shaft 3(B). The cross-shaped key 3(E) is to angularly connect any one of the followers 3(D) with the output shaft 3(B) together for causing engagement between 3(D) and 3(B) to impart motion from 3(D) to 3(B). In accordance with said embodiment of this invention, when the engine 1 runs, the drive gear 1(B) drives its follower 1(C). While, the clutch 1(D) is normally engaged, the drive gear 2(A) driven by said engine 1 is driving the idler gear 2(B) through the clutch 1(D). The idler gear 2(B) is then driving any one of the cluster gears 3(A). Then, any one of the followers 3(D) which is engaging with the output shaft 3(B) of the gear box 3 through the cross shaped key 3(E), is imparting the motion to the output shaft 3 (B) of the gear box 3. Now the output shaft 3(B) or 4(A) is in turn driving the rear wheel 4. The cluster gears 3(A) are in constant mesh with the gears 3 (D) bom on the wheel shaft 3 (B), driven at different speed ratios. When the gearbox 3 is in neutral and the kick-starter lever 2(C) is operated by the rider for starting the engine 1, the ratchet gear 2(E), automatically engages with the first ratchet gear 2(D) to drive the idler gear 2(B). The idler gear 2(B) is in turn driving the drive gear 2(A). The drive gear 2(A) then drives the follower 1(C) through the clutch 1(D) and said follower 1(C) is in turn driving the drive gear 1(A). Then, the drive gear 1(A) is driving the crankshaft 1(A) of engine 1 so as to crank the same (engine 1). But, the set of the cluster gears 3(A) of the gearbox 3 being driven by said idler gear 2(B), is then ireeiy rotatmg without any load. Still furthermore, in one preferred embodiment of this invention, the engine is specifically a four-stroke engine with petrol or diesel as its fuel for better pollution control and more fuel economy than the two stroke engines. In another preferred embodiment of this invention, said engine may also be a two-stroke engine with petrol or diesel as its fuel for lighter and simpler construction as well as higher torque/speed ratio when compared to four stroke engines. Furthermore, in further embodiment of this invention, said manual operating gearbox 3 is also replaceable by any automatic gearbox in any known way. In an another particular specific feature of this invention, said automatic gearbox is as a variomatic gearbox also being a known one. According to this invention, as the transverse distance of the centre of gravity from the longitudinal central plane is minimal, the balancing of the present scooters while handling from on-stand to off-stand positions, is significantly improved or enhanced. Additionally, when a sudden brake as required even suddenly locks the rear wheel 4, it significantly minimizes the skidding nature in the lateral direction due to the less moment of the couple being acting on these scooters about their yawing axes. This is the most significant advantage that these scooters have more instantaneous transverse-stability even for the sudden brake applications while at high speeds than the conventional scooters. Further, it is significant that it safely improves or increases both the acceleration and the deceleration limits of these scooters than the conventional scooters due to less moment of the couple acting thereon about their transverse axes during both acceleration and the deceleration. (Because of the lower location of the centre of gravity of these scooters.) Furthermore, the acceleration limit of the present scooter is safely improved or increased as compared to the conventional scooter, since the longitudinal distance of the centre of gravity of this scooter from the front wheel axis, is minimal. Still further, according to this invention, the above said all gear transmission means 2 finds its advantages of less noise in operation, less maintenance, more life span between successive failures, no drive-slip, rigid drive, less wear, no slackness, less replacement of its parts and the like over the conventional chain-drive Moreover, the scooter according to the present invention is comparatively safer on the existing road conditions over the conventional scooters and hence, the present scooters may find wide applications. The terms and expressions used herein are illustrative and not limitative in any sense. WE CLAIM; 1. A scooter having a centrally mounted engine with an all gear transmission means, wherein said gear transmission means is operatively connected between the crankshaft of said engine and the drive gear of a variable speed ratio gear box, the rear wheel of said scooter is mounted on the output shaft of said gear box, the axes of the shaft(s) of said gear transmission means and the input and output shafts of said gearbox are lying in a plane slightly inclined with respect to the horizontal plane, the cylinder-axis of said engine is slightly inclined upwardly to said inched plane so as to give sufficient ground clearance, the protruding ends of both said engine crankshaft and gear box output shaft being mutually opposite to each other along their axes, both said gear transmission means and said gear box being located laterally on one side of said rear wheel or the longitudinal central plane, the perpendicular distance between the axes of said engine-crankshaft and rear wheel being minimal and sufficient enough to maintain a radial clearance between said rear wheel and the crankcase of said engine, the perpendicular distance between said engine-cylinder-axis and the longitudinal central plane being small and enough to maintain sufficient axial clearance between said rear wheel and the assembly of said both gear transmission means and gear box, and the distance of centre of gravity of said scooter from both the longitudinal central plane and the ground plane as well as the longitudinal distance of centre of gravity of said scooter from its front wheel axis are minimal. 2. A scooter as claimed in claim 1, wherein said gear transmission means comprises a clutch engaging with a kick starter assembly. 3. A scooter as claimed in claims 1 and 2, wherein a driven gear and a drive gear are provided to form a reverted gear train so as to be connected together through said clutch assembly. 4. A scooter as claimed in claim 3, wherein the driven gear and the drive gear are operatively connected to the driving plates and driven plates respectively, of said clutch assembly, and the former gear being driven by the drive gear and another drive gear driving an idler gear, the former drive gear being rigidly connected to said engine crank shaft and said idler gear being loosely mounted on said kick starter shaft, said idler gear driving an input shaft of said gear box and the output shaft of said gear box being operatively and co-axially connected to the wheel shaft of said rear wheel on the same side of said engine. 5. A scooter as claimed in claims 2 to 4, wherein the axes of said crank shaft of said engine, said clutch assembly and said kick-starter shaft, are lying in said inclined plane 6. A scooter as claimed in claims 2 to 5, wherein said clutch assembly, said kick-starter assembly and said gearbox, are enclosed in a single cover comprising two halves, one of which is detachably fitted over the other which is integrated with said crankcase of said engine. 7. A scooter as claimed in claims 4 to 6, wherein said idler gear is compounded with a ratchet gear, which is to be driven by another ratchet gear being co-axial to the former and also being secured against rotation with respect to the said kick-starter and the assembly of said latter ratchet gear with said kick-starter is loaded with a torsional spring for returning said kick-starter to its original position. 8. A scooter as claimed in claims 4 to 7, wherein said idler gear is constantly meshing with one of the cluster gears of input shaft of said gearbox. 9. A scooter as claimed in claims 4 to 8, wherein the follower of each cluster gear of said gear box, is loosely mounted on said output shaft of said gearbox, and the followers form reverted gear train(s) to each other and are free to rotate at different speeds with respect to each other so as to impart motion from the cluster gear to the respective follower through any one of the gear trains as desired. 10. A scooter as claimed in claim 9, wherein any one of the said followers is enable to be secured with said output shaft against rotation with respect to each other by using a cross shaped key which is rotatably connected to a pin controlled by any known gear shifting mechanism and is also axially movably connected in the said output shaft so as to simultaneously connect any one of the said followers and said output shaft together for causing engagement therebetween and to impart motion fi-om the former part to the latter part with any one of the speed ratios therebetween, as required. 11. A scooter as claimed in claims Ito 7, wherein said gearbox is any known automatic gearbox preferably a variomatic gearbox. 12. A scooter as claimed in claims 1 to 11, wherein said engine is a four-stroke engine or a two-stroke engine with petrol or diesel as the fiiel. 13. A scooter having a centrally mounted engine with an all gear transmission means, substantially as herein described and illustrated with respect to the accompanying drawings.

Documents:

2135-mas-1998 abstract duplicate.pdf

2135-mas-1998 abstract.pdf

2135-mas-1998 claims duplicate.pdf

2135-mas-1998 claims.pdf

2135-mas-1998 correspondence others.pdf

2135-mas-1998 correspondence po.pdf

2135-mas-1998 description (complete) duplicate.pdf

2135-mas-1998 description (complete).pdf

2135-mas-1998 drawings duplicate.pdf

2135-mas-1998 drawings.pdf

2135-mas-1998 form-1.pdf

2135-mas-1998 form-13.pdf

2135-mas-1998 form-19.pdf

2135-mas-1998 form-26.pdf