Title of Invention

OVERRIDE MECHANISM FOR ELECTRIC GEARSHIFT SYSTEM AND METHOD OF MANUFACTURING OVERRIDE MECHANISM THEREOF

Abstract

Override Mechanism For Electric Gearshift System And Method Of Manufacturing Override Mechanism Thereof ABSTRACT This invention relates to the Override Mechanism for Electric Gearshift System and Method of manufacturing override mechanism thereof. Override mechanism for electric gearshift system in accordance with this invention basically comprises of pre loaded compression means, pre loaded torsion means, gearshift lever, gearshift shaft, locking means for gear shift lever, stopper for gear shift lever and plurality of washers, wherein said torsion means is provided on said gear shift shaft at connecting end to gear shaft, one end of said torsion means is adopted to be fixed to gear box casing and other end is fixed to gear shift shaft through first washer, said gear shift shaft is provided with second washer adjacent to said torsion means towards connecting end to gear shaft to prevent sliding off of said torsion means, said compression means is provided on said gear shift shaft and placed adjacent to said first washer, said gear shift lever adopted to be meshed with actuator gear is provided on said gear shift shaft adjacent to said compression means with a provision of locking and unlocking on said gear shift shaft, said gear shift shaft is provided with a stopping means to prevent the sliding away of said gear shift lever. During normal operation override mechanism is connected to gear shaft and one end of said torsion means is fixed to the gear box casing after preloading and gear shift lever is engaged with actuator gear of electric gear shift system. In case of failure of electric gearshift system, the said locking means is required to be removed by the driver. Because of removal of said locking means the compression means pushes the gearshift lever towards the stopper end which disengages the gearshift lever from the actuator gear. Then the said torsion means forces the gearshift shaft to rotate to enable the gear to engage in pre-decided position. Fig l

Full Text

FORM 2 THE PATENTS ACT 1970 (39 of 1970) & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION (See Section 10; rule 13) TITLE OF THE INVENTION Override Mechanism For Electric Gearshift System And Method Of Manufacturing Override Mechanism Thereof APPLICANTS TATA MOTORS LIMITED, an Indian company having its registered office at Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001 Maharashtra, India INVENTORS Srinivasa Raju Gavarraju, Ashfaque Ahmed Ansari both Indian Nationals of TATA MOTORS LIMITED, an Indian company having its registered office at Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001 Maharashtra, India PREAMBLE TO THE DESCRIPTION The following complete specification particularly describes the invention and the manner in which it is to be performed. FIELD OF INVENTION This invention relates to electric gear shift system used in vehicles and more particularly it relates to override mechanism used for electric gearshift systems with CVT (Continuously Variable Transmission). BACKGROUND OF INVENTION The automotive vehicles typically employ a driver-operated mechanical gearshift assembly which controls the transmission. Such shifters generally employ a shift lever which is moved by hand between various gear settings (Forward, Neutral & Reverse). While such systems are widely used and some of the drawbacks associated with the said system are: 1. Effort required in shifting the gear is more 2. Wear and tear of the components is high 3. Very difficult to accommodate safety interlocks Above said drawbacks can be addressed by an electric gearshift system. Electric gearshift system is an electro-mechanical system comprising gearbox, gearshift switch, electronic control unit (ECU), actuator, gear display unit, gearshift lever, battery, gear position sensor, vehicle speed sensor, engine speed sensor and brake switch. When driver operates the gearshift switch, the commanded signal goes to the ECU and based on other inputs like gear position feedback signal, vehicle speed signal, engine speed signal and brake switch signal, the ECU commands the actuator to rotate in clockwise or anti-clockwise direction so as to engage the gear in forward, neutral or reverse position. US 5,934,432 (D1) relates to an actuator system utilizing an electric motor controlled actuator and having a pressurized fluid-operated override mechanism for effecting rapid clutch movements not requiring precise control. Dl also have solenoid-controlled pneumatic override actuator for rapidly disengaging the clutch and/or for moving the clutch from a fully disengaged position to the touch point of incipient engagement whereas the present invention discloses an override mechanism for electric gearshift system which facilitates the vehicle movement in case of failure of electric gearshift system. The present invention does not use pressurized fluid or hydraulic fluid for working of override mechanism for electric gearshift system. The constructional features and arrangement of different component of the present invention is totally different from D1. US 4,282,780 (D2) discloses an electric transmission control apparatus in which the shift pattern is controlled in accordance with various loads given to the prime engine. The automatic transmission unit (14) is provided with 1-2 shift solenoid (13) for selectively conducting the shift operation between first and second forward speed ranges under the drive range of the transmission (14) [mention in colum-2 at para. 2] whereas the present invention provide override mechanism for electric gearshift system which facilitates the vehicle movement in case of failure of electric gearshift system. The override mechanism is connected to gear shaft through its connecting end and one end of the torsion means is fixed to the gear box casing after preloading and gear shift lever is engaged with actuator gear of electric gear shift system. But in D2, transmission unit (14) is coupled to combustion engine of the vehicle and is provided with a manual shift lever. The components and arrangement of different components of D2 is totally different from the present invention. The drawback with said electric gearshift systems is the potential loss of transmission control when there is a failure of electric gearshift system. That is, the operator could lose the ability to shift gears. This could cause the inability to even shift the vehicle into forward gear in order to enable the vehicle to be moved to the nearby service station for repair. In order to overcome the above said drawback, this invention is devised. OBJECTS OF INVENTION The main object of this invention is to provide an override mechanism for electric gearshift system which facilitates the vehicle movement in case of failure of electric gearshift system. Yet another object of this invention is to provide method of overriding during failure of electric gearshift system. Yet another object of this invention is to provide an override mechanism for electric gearshift system which is simple in construction, ease for operation and cost effective. STATEMENT OF INVENTION Override mechanism for electric gearshift system comprises of pre loaded compression means, pre loaded torsion means, gearshift lever, gearshift shaft, locking means for gear shift lever, stopper for gear shift lever and plurality of washers, wherein said torsion means is provided on said gear shift shaft at connecting end to gear shaft, one end of said torsion means is adopted to be fixed to gear box casing and other end is fixed to gear shift shaft through first washer, said gear shift shaft is provided with second washer adjacent to said torsion means towards connecting end to gear shaft to prevent sliding off of said torsion means, said compression means is provided on said gear shift shaft and placed adjacent to said first washer, said gear shift lever adopted to be meshed with actuator gear is provided on said gear shift shaft adjacent to said compression means with a provision of locking and unlocking on said gear shift shaft, said gear shift shaft is provided with a stopping means to prevent the sliding away of said gear shift lever. BRIEF DESCRIPTION OF INVENTION Override mechanism for electric gearshift system in accordance with this invention basically comprises of pre loaded compression means, pre loaded torsion means, gearshift lever, gearshift shaft, locking means for gear shift lever, stopper for gear shift lever and plurality of washers, wherein said torsion means is provided on said gear shift shaft at connecting end to gear shaft, one end of said torsion means is adopted to be fixed to gear box casing and other end is fixed to gear shift shaft through first washer, said gear shift shaft is provided with second washer adjacent to said torsion means towards connecting end to gear shaft to prevent sliding off of said torsion means, said compression means is provided on said gear shift shaft and placed adjacent to said first washer, said gear shift lever adopted to be meshed with actuator gear is provided on said gear shift shaft adjacent to said compression means with a provision of locking and unlocking on said gear shift shaft, said gear shift shaft is provided with a stopping means to prevent the sliding away of said gear shift lever. During normal operation override mechanism is connected to gear shaft and one end of said torsion means is fixed to the gear box casing after preloading and gear shift lever is engaged with actuator gear of electric gear shift system. In case of failure of electric gearshift system, the said locking means is required to be removed by the driver. Because of removal of said locking means the compression means pushes the gearshift lever towards the stopper end which disengages the gearshift lever from the actuator gear. Then the said torsion means forces the gearshift shaft to rotate to enable the gear to engage in pre-decided position. BRIEF DESCRIPTION OF DRAWINGS Figure 1 shows first embodiment of override mechanism during normal operation of electric gearshift system Figure 2 shows second embodiment of override mechanism during normal operation of electric gearshift system Figure 3 shows gear shift lever used in this invention Figure 4 (a) & 4 (b) show torsion and compression springs respectively Figure 5 shows overriding mechanism during failure of electric gear shift system DETAILED DESCRIPTION OF INVENTION Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same, Referring to figures 1, 3, 4(a), 4(b) and 5, First embodiment of override mechanism (A) for electric gearshift system in accordance with this invention comprises of pre loaded compression means (1), pre loaded torsion means (2), gearshift lever (3), gearshift shaft (4), locking means for gear shift lever (5), stopper for gear shift lever (8) and plurality of washers (6,7). Wherein said torsion means (2) is provided on said gear shift shaft (4) at connecting end (12) to gear shaft, one end of said torsion means (2) is adopted to be fixed to gear box casing and other end is fixed to gear shift shaft (4) through washer (7). Said gear shift shaft (4) is provided with second washer (6) adjacent to said torsion means towards connecting end (12) to gear shaft to prevent sliding off of said torsion means (2). Said compression means (1) is provided on said gear shift shaft and placed adjacent to said washer (7). Said gear shift lever (3) is provided on said gear shift shaft (4) adjacent to said compression means (1) with a provision of locking and unlocking (5) on said gear shift shaft. Said gear shift shaft (4) is provided with a stopping means (8) to prevent the sliding away of said gear shift lever (3). Said gear shift shaft is also provided with one more washer (6) adjacent to the said torsion spring (2) towards connecting end (12) to gear shaft to prevent sliding off of said torsion spring (2). During normal operation said override mechanism (A) is connected to gear shaft through its connecting end (12) and one end (13) of said torsion means (2) is fixed to the gear box casing (11) after preloading and gear shift lever (3) is engaged with actuator gear (10) of electric gear shift system (not shown). In case of failure of electric gearshift system, the said locking means (5) is required to be removed by the driver from its position. Because of removal of said locking means the compression means (1) pushes the gearshift lever (3) towards the stopper end which disengages the gearshift lever (3) from the actuator gear (10). Then the said torsion means (2) forces the gearshift shaft (4) to rotate and which enable gear to engage in pre-decided position. Referring to figures 2, 3, 4(a), 4(b) and 5, Another embodiment of override mechanism (A) for electric gearshift system in accordance with this invention comprises of pre loaded compression means (1), pre loaded torsion means (2), gearshift lever (3), gearshift shaft (4), locking means (5) for gear shift lever (3), stopper (8) for gear shift lever (3), washer (6) and extended arm (7), wherein said torsion means (2) is provided on said gear shift shaft (4) at connecting end (12) to gear shaft, one end of said torsion means (2) is adopted to be fixed to gear box casing (11) and other end is fixed to gear shift shaft (4) through fixing means (7) provided on said washer (6), said gear shift shaft (4) is provided with torsion means (2), said compression means (1) is provided on said gear shift shaft (4) inside said torsion means (2) and placed adjacent to said washer (6), said gear shift lever (3) adopted to be meshed with actuator gear (10) is provided on said gear, shift shaft (4) adjacent to said compression means (1) with a provision of locking and unlocking (5) on said gear shift shaft (4), said gear shift shaft (4) is provided with a stopping means (8) to prevent the sliding away of said gear shift lever (3). During normal operation said override mechanism (A) is connected to gear shaft through its connecting end (12) and one end (13) of said torsion means (2) is fixed to the gear box casing (11) after preloading and gear shift lever (3) is engaged with actuator gear (10) of electric gear shift system (not shown). In case of failure of electric gearshift system, the said locking means (5) is required to be removed by the driver from its position. Because of removal of said locking means the compression means (1) pushes the gearshift lever (3) towards the stopper end which disengages the gearshift lever (3) from the actuator gear (10). Then the said torsion means (2) forces the gear shift shaft (4) to rotate and which enable gear to engage in pre-decided position. Method of manufacturing override mechanism comprises of: i. Said torsion means (2) is provided on said gear shift shaft (4) at connecting end (12) to gear shaft, one end of said torsion means (2) is adopted to be fixed to gear box casing (11) and other end is fixed to gear shift shaft (4) through washer (7). Said gear shift shaft (4) is also provided with a washer (6) adjacent to the said torsion means (2) towards connecting end (12) to gear shaft to prevent sliding off of said torsion means (2). ii. Said compression means (1) is provided on said shaft in compressed state and placed adjacent to said washer (6). iii. Said gear shift lever (3) is provided on said gear shift shaft (4) adjacent to said compression means (1) with a provision of locking and unlocking (5) on said gear shift shaft (4). iv. Said gear shift shaft (4) is provided with a stopping means (8) to prevent the sliding away of said gear shift lever (3). The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof. WE CLAIM 1. An override mechanism for electric gearshift system comprises of pre loaded compression means (1), pre loaded torsion means (2), gearshift lever (3), gearshift shaft (4), locking means (5) for gear shift lever (3), stopper (8) for gear shift lever (3) and plurality of washers (6, 7), wherein said torsion means (2) is provided on said gear shift shaft (4) at connecting end (12) to gear shaft, one end (13) of said torsion means (2) is adopted to be fixed to gear box casing (11) and other end is fixed to gear shift shaft (4) through first washer (7), said gear shift shaft (4) is provided with second washer (6) adjacent to said torsion means (2) towards connecting end (12) to gear shaft to prevent sliding off of said torsion means (2), said compression means (1) is provided on said gear shift shaft (4) and placed adjacent to said first washer (7), said gear shift lever (3) adopted to be meshed with actuator gear (10) is provided on said gear shift shaft (4) adjacent to said compression means (1) with a provision of locking and unlocking on said gear shift shaft (4), said gear shift shaft (4) is provided with a stopping means (8) to prevent the sliding away of said gear shift lever (3). 2. An override mechanism for electric gearshift system comprises of pre loaded compression means (1), pre loaded torsion means (2), gearshift lever (3), gearshift shaft (4), locking means (5) for gear shift lever (3), stopper (8) for gear shift lever (3) and washer (6), wherein said torsion means (2) is provided on said gear shift shaft (4) at connecting end (12) to gear shaft, one end (11) of said torsion means (2) is adopted to be fixed to gear box casing (11) and other end is fixed to gear shift shaft (4) through fixing means (7) provided on said washer (6), said gear shift shaft (4) is provided with torsion means (2), said compression means (1) is provided on said gear shift shaft (4) inside said torsion means (2) and placed adjacent to said washer (6), said gear shift lever (3) adopted to be meshed with actuator gear (10) is provided on said gear shift shaft (4) adjacent to said compression means (1) with a provision of locking and unlocking (5) on said gear shift shaft (4), said gear shift shaft (4) is provided with a stopping means (8) to prevent the sliding away of said gear shift lever (3). 3. The override mechanism for electric gearshift system as claimed in claims 1 and 2 wherein said compression means is a compression spring. 4. The override mechanism for electric gearshift system as claimed in claims 1 and 2 wherein said torsion means is a torsion spring. 5. The override mechanism for electric gearshift system as claimed in any of claims 1 to 4 wherein one end of said gear shift lever is provided with involutes profiled teeth for engaging with actuator gear and other end of said gear shift lever is provided with provisions for sliding and locking in its place. 6. The override mechanism for electric gearshift system as claimed in any of claims 1 to 5 wherein said locking means for gear shift lever is a lock pin attached with pull cable. 7. The override mechanism for electric gearshift system as claimed in any of claims 2 to 6 wherein said fixing means is an arm extended from surface of said washer. 8. The override mechanism for electric gearshift system as claimed in claim 7 wherein said fixing means is provided inside or outside of said torsion means. 9. A method of manufacturing override mechanism comprises of: i. Said torsion means (2) is provided on said gear shift (4) shaft at connecting end (12) to gear shaft, one end (13) of said torsion means (2) is adopted to be fixed to gear box casing (11) and other end is fixed to gear shift shaft (4) through washer (7). Said gear shift shaft (4) is also provided with a washer (6) adjacent to the said torsion means (2) towards connecting end (12) to gear shaft to prevent sliding off of said torsion means (2). ii. Said compression means (1) is provided on said shaft in compressed state and placed adjacent to said washer (6). iii. Said gear shift lever (3) is provided on said gear shift shaft (4) adjacent to said compression means (1) with a provision of locking and unlocking (5) on said gear shift shaft (4). iv. Said gear shift shaft (4) is provided with a stopping means (8) to prevent the sliding away of said gear shift lever (3).

Documents:

2310-MUM-2007-ABSTRACT(21-2-2014).pdf

2310-MUM-2007-ABSTRACT(27-2-2012).pdf

2310-mum-2007-abstract.doc

2310-mum-2007-abstract.pdf

2310-MUM-2007-CLAIMS(21-2-2014).pdf

2310-MUM-2007-CLAIMS(AMENDED)-(27-2-2012).pdf

2310-mum-2007-claims.doc

2310-mum-2007-claims.pdf

2310-mum-2007-correspondence(13-12-2007).pdf

2310-MUM-2007-CORRESPONDENCE(25-7-2008).pdf

2310-mum-2007-correspondence-received.pdf

2310-mum-2007-description (complete).pdf

2310-MUM-2007-DRAWING(21-2-2014).pdf

2310-mum-2007-drawing(23-11-2007).pdf

2310-mum-2007-form 1(13-12-2007).pdf

2310-MUM-2007-FORM 13(21-2-2014).pdf

2310-MUM-2007-FORM 13(27-2-2012).pdf

2310-mum-2007-form 18(10-12-2007).pdf

2310-MUM-2007-FORM 2(TITLE PAGE)-(21-2-2014).pdf

2310-mum-2007-form 2(title page)-(23-11-2007).pdf

2310-mum-2007-form 3(23-11-2007).pdf

2310-MUM-2007-FORM 3(25-7-2008).pdf

2310-mum-2007-form 8(10-12-2007).pdf

2310-mum-2007-form 9(10-12-2007).pdf

2310-mum-2007-form-1.pdf

2310-mum-2007-form-2.doc

2310-mum-2007-form-2.pdf

2310-mum-2007-form-26.pdf

2310-mum-2007-form-3.pdf

2310-MUM-2007-GENERAL POWER OF ATTORNEY(27-2-2012).pdf

2310-MUM-2007-MARKED COPY(21-2-2014).pdf

2310-MUM-2007-MARKED COPY(27-2-2012).pdf

2310-MUM-2007-REPLY TO EXAMINATION REPORT(27-2-2012).pdf

2310-MUM-2007-REPLY TO HEARING(21-2-2014).pdf

2310-MUM-2007-SPECIFICATION(AMENDED)-(21-2-2014).pdf

2310-MUM-2007-SPECIFICATION(AMENDED)-(27-2-2012).pdf

2310-MUM-2007-URDIP SEARCH REPORT(31-12-2010).pdf

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