Title of Invention

A CONSTANT MESH GEARING SYSTEM FOR AN AUTOMOBILE

Abstract

A constant mesh gearing system for an autom obile comprising first and second star selectors respectively fixed to first and second profile rods, the first profile rod being disposed with in the second profile rod; a gear lever, a shiller shaft provided with upper and lower selector arms for respectively moving the first and second profile rods) along with the first and second star selectors,the said selector arms being disposed radially and axially apart such that the upward and downward movement of the shifler shaft couples the selector arm to the corresponding profile rod; a sector plate through which the rotational movement of the shifler shaft is activated by the 'driver of the vehicle; and slider crank means through which the upward and downward m ovem ent of the shifter shaft is activated by the said driver whereby the gear selection of neutral to gear I, gear I to neutral and neutral to gear II are obtaIned through the second profile rod and correspondIng star selector; and the gear selection of neutral to gear III, gear III to neutral and neutral to gear IV is obtained through the first profile rodand its corresponding star selector/ ABSTRACT A constant mesh gearing system for an automobile 263 MAS 03 A constant mesh gearing system for an automobile comprising first and second star selectors respectively fixed to first and second profile rods, the first profile rod being disposed within the second profile rod; a gear lever, a shifter shaft provided with upper and lower selector arms for respectively moving the first and second profile rods, along with the first and second star selectors,the said selector arms being disposed radially and axially apart such that the upward and downward movement of the shifter shaft couples the selector arm to the corresponding profile rod; a sector plate through which the rotational movement of the shifter shaft is activated by the driver of the vehicle; and slider crank means through which the upward and downward movement of the shifter shaft is activated by the said driver whereby the gear selection of neutral to gear I, gear I to neutral and neutral to gear II are obtained through the second profile rod and corresponding star selector; and the gear selection of neutral to gear III, gear III to neutral and neutral to gear IV is obtained through the first profile rodand its corresponding star selector/

Full Text

This invention relates to a constant mesh gearing system for an automobile. The constant mesh gear boxes in automobiles have two sets of gears always in constant contact, namely, the cluster gears driven by the engine and the speed gears driving the wheels. Although a set of gears is always in constant mesh, the appropriate gear pair is chosen by the driver with the help of a single star selector, which moves inside the speed gears. The star selector is housed inside the driven shaft and can slide axially through peripheral slots. Hie star selector helps in gear engagement by aligning itself with a particular gear through slots made on the inner peripheral surfaces of the speed gears. The star selector is locked to one end of the profile rod so that the longitudinal movement of the rod results in fore and aft movement of the star selector. The profile rod has precision-machined grooves on its outer surface to facilitate exact axial movement of the star selector to engage a particular gear pair. The profile rod also helps in locking the star selector in that particular position with the help of a ball catch arrangement. The profile rod moves to and fro with the rotational movement of a selector arm. When the driver moves the gear lever it rotates a sector plate mounted outside the engine on the same axis as the selector arm. When the sector plate rotates it results in angular movement of the selector arm which in turn moves the profile rod to and fro. Thus when the driver shifts the gear from I to IV, the sector plate and selector arm rotate and push the profile rod and star selector from one end to the other resulting in the selection of the desired gear pair. The major drawback of the present system is that for the driver, the gear lever movement is in one plane. During gear shifting there is likelihood mat the driver may skip one gear and go directly to the next. For instance, instead of moving from gear II to III, he might pass through III and engage directly IV and vive versa This will result in jerky driving for the driver and a rough ride for the passengers. The invention proposed herein overcomes the above drawback of gear slippage and facilitates distinct and sequential gear engagement. For instance, if the driver wants to move from gear II to gear III, the gear lever moves from one place to another. Gears 1 and 11 move in one plane and gears III and IV move in another plane ensuring gear engagement only at the extremities of lever movement in each plane. The position of gear lever knob distinctly indicates the particular gear to the driver. The constant mesh gearing system for an automobile, according to this invention, comprises first and second star selectors respectively fixed to first and second profile, rods, the first profile rod being disposed within the second profile rod; a gear lever; a shifter shaft provided with upper and lower selector arms for respectively moving the first and second profile rods, along with the first and second star selectors, the said selector arms being disposed radially and axially apart such that the upward and downward movement of the shifter shaft couples the selector arm to the corresponding profile rod; a sector plate through which the rotational movement of the shifter shaft is activated by the driver of the vehicle; and slider crank means through which the upward and downward movement of the shifter shaft is activated by the said driver, whereby the gear selection of neutral to gear 1, gear I to neutral and neutral to gear II are obtained through the second profile rod and corresponding star selector; and the gear selection of neutral to gear HI, gear III to neutral and neutral to gear IV is obtained through the first profile rod and its corresponding star selector. This invention will now be described in grerater detail by reference to the accompanying drawings which illustrate by way of example, and not by way of limitation, one of possible embodiments of the gearing system proposed herein, Fig.l illustrating the gear knob positions according to the known art Fig.2 illustrating the gear knob positions according to this invention Fig. 3 illustrating profile rods and star selector assembly of the said embodiment Fig. 4 illustrating the sector arms and sector plate assembly of the said embodiment And Fig. 5 illustrating the gear selection and shift arrangement with the gear shift lever, the gear selection cables, and the gear shifting cables. The knob positions of the gear system known to the art is illustrated in Fig. 1 of the drawings while the knob positions of is illutrated in Fig.2. The invention proposed herein overcomes the drwaback of gear slippage of the known system and facilitates distinct and sequential gear engagement. For example, if the driver wants to move from gear II to gear III, the gear lever moves from one plane to another. Gears I and II move in one plane and gears III and IV move in another plane ensuring gear engagement only at the extremeties of lever movement in each plane. The position of gear lever knob distinctly indicates particular gear to the driver. The known system uses single profile rod, single star selector and single selector arm for gear engagement resulting in an unsatisfactory single plane gear lever knob movement. The invention proposed herein uses two profile rods, two star selectors and two selector arms for gear engagement to provide a two plane gear lever knob movement ("H" shift). Compared to the known system, this invention gives distinct and sequential gear shift arrangement which is more user friendly and has better shift quality. As stated above, the invention proposed herein uses two star selectors , two profile rods , two selector arms and a gear lever which swivels on two axes to achieve a unique gear selection and engagement. The profile rods PI and P2 are placed one inside the other and the shifter shaft F has two selector arms Tl and T2 each designated to move one profile rod and the star selector attached to it. The profile rods have collars C1 and C2 at one end to receive the selector arms Tl and T2 as desired by the driver. The inner profile rod P1 is moved using upper selector arm Tl and the outer profile rod P2 is moved using the lower selector arm T2. The said arms are kept radially and axially apart so that the upward and downward movement of the shifter shaft F precisely couples the selector arms with the respective profile rods. The rotational movement of the shifter shaft F is activated by the driver through a sector plate J mounted outside the crank case of the engine of the automobile. Similarly upward and downward movement of the shifter shaft F is activated by the driver through a slider crank mechanism mounted outside the crank , case. When the driver desires to engage gear I, he moves the gear lever L first to gear I-II plane which will result in rotation of crank E and upward motion of shifter shaft F engaging lower selector arm T2 on outer profile rod P2. After reaching gear I-II plane and when the driver moves the knob M of gear lever L further to gear I position, the outer profile rod P2 moves forward pushing the star selector S2 to align with the first gear wheel. The outer profile rod has three profiled grooves Q to provide gear I, neutral and gear II engagements. Hence the gear selection of neutral to gear I, gear I to neutral and neutral to gear II are obtained through the outer profile rod and star selector. Similarly, the inner profile rod PI and its star selector SI provides gear III, neutral and gear IV engagements. Fig.5 illustrates the gear selection and shift arrangement with the gear shift lever, the gear selection cables, and the gear shifting cables. The terms and expressions herein are of description and not of limitation, since these do not exclude any equivalent of the features illustrated and described, but it is understood that various other embodiment of the gearing system proposed herein are possible without departing from the scope and ambit of this invention. We Claim: 1. A constant mesh gearing system for an automobile comprising first and second star selectors respectively fixed to first and second profile rods, the first profile rod being disposed within the second profile rod; a gear lever; a shifter shaft provided with upper and lower selector arms for respectively moving the first and second profile rods, along with the first and second star selectors, the said selector arms being disposed Tadially and axially apart such that the upward and downward movement of the shifter shaft couples the selector arm to the corresponding profile rod; a sector plate through which the rotational movement of the shifter shaft is activated by the driver of the vehicle; and slider crank means through which the upward and downward movement of the shifter shaft is activated by the said driver, whereby the gear selection of neutral to gear I, gear I to neutral and neutral to gear II are obtained through the second profile rod and corresponding star selector; and the gear selection of neutral to gear 111, gear 111 to neutral and neutral to gear IV is obtained through the first profile rod and its corresponding star selector. 2. A gearing system as claimed in Claim 1 wherein each profile rod has a collar at one end for receiving the corresponding selector arm, 3. A gearing system as claimed in any one of the preceding Claims wherein the sector plate and slider crank means are mounted outside the crank case of the vehicle. 4. A gearing system as claimed in any one of the preceding Claims wherein each profile rod locks the corresponding star selector in gear engagement position by a ball catch arrangement. 5. A gearing system as claimed in any one of the preceding Claims wherein each profile rod has grooves on its outer surface to facilitate exact axial movement of the corresponding star selector for engaging a particular gear pair. 6. A constant mesh gearing system for an automobile substantially as herein described with reference to, and as illustrated in, the accompanying drawings.

Documents:

0263-che-2003 abstract.pdf

0263-che-2003 claims-duplicate.pdf

0263-che-2003 claims.pdf

0263-che-2003 correspondence-others.pdf

0263-che-2003 correspondence-po.pdf

0263-che-2003 description (complete)-duplicate.pdf

0263-che-2003 description (complete).pdf

0263-che-2003 drawings.pdf

0263-che-2003 form-1.pdf

0263-che-2003 form-19.pdf

0263-che-2003 form-26.pdf