Title of Invention

HEAD LAMP LEVELING DEVICE

Abstract

Title: Head Lamp Leveling Device 27 MAY 2008 The present novel mechanical headlamp leveling system is devised to provide compact, simpler & cheaper technology for achieving the downward inclination of the cut off of dipped beam head lamps. To achieve the correction in cut off position it uses bevel gears, push-pull cable & components movement on the wedge action principle. As shown in figure 1 , this device is activated by rotating a control knob (3) located on the dashboard of vehicle, which pushes / pulls the push pull cable (6) , with the help of bevel gears (4) & (5) ,mounted on the housing (1). The cable in turn activates the pair of wedge (8) & (10) mounted on the base plate (14). This wedge action further causes the headlamp to tilt about the virtual axis X-X, formed by two screws (12b), (12c) mounted in the bottom of base plate (14). 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 Head Lamp Leveling Device 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 Govind Kumar Binani, A K Agarwal, Sunil Kakaye, P. N Gadgil all Indian nationals of TATAMOTORS LIMITED, an Indian company having its registered office at Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001 Maharashtra, India GRANTED PREAMBLE TO THE DESCRIPTION The following Complete specification particularly describes the invention and the manner in which it is to be performed. 20-2-2007 20 FEB 2007 Field of Invention: This invention relates to a headlamp leveling device and more particularly to Headlamp leveling device operated by mechanical linkages. Background of the Invention: Vehicular headlamps with leveling device are known for performing leveling adjustment to adjust an optical axis direction which changes due to weights of objects loaded in a vehicle and a loading position. (See US 6,428,196 and US6,918,687 as examples). Presently used head lamp leveling system uses electric motor, resistive switch and electrical cables to adjust the cut off pattern of dipped beam head lamp. Resistive switch consist of a resistance bank, which is connected across the battery supply. Resistance bank is used as a potentiometer and the output of the switch is fed to the sensor input of the electric motor. Switch is mounted on the dashboard. Switch has a rotary knob, which rotates either in up-down direction or anticlockwise direction. Switch has a positions marked (0,1,2,3 etc) on its housing which corresponds to the vehicle loading conditions as per regulation (AIS-008). Rotary knob is held at different positions by proving detents in desired location. When the switch is operated from 0 position to any other position marked on switch housing (1,2,3 etc) desired voltage is applied to electric motor, which in turn decides the inclination of the headlamp cut off beam. Electric motor consists of stepper motor, electronic controller, gear assembly and a shaft. Motor is mounted on the headlamp and its shaft connects the headlamp rim and base plate. Based on the voltage level received from switch, electronic controller decides voltage to be applied to the stepper motor. Stepper motor in turn moves the gear assembly and causes the shaft to move forward or backward. The Electronic controller inside the motor decides shaft direction. Electrical cables are used for interconnection of motor, switch, battery and combiswitch. JP 5085256 discloses a leveling device for car headlamp comprising an electric motor connected to a control section provided in an optical axis level control section. The rotation of the threaded member (output shaft) is converted into a linear (axial) movement of an optical axis changing rod member through a driving mechanism fixed to the output shaft and a nut member threadedly engaged with the thread mechanism. A control circuit compares the detection signal detected by a variable resistor and compared with the set value of the optical axis and the electric motor is driven when the differece between the detection signal and the set value of the optical axis is lessened. Figure (6) shows the existing motorized headlamp leveling system along with circuit diagram used on automotive vehicles. Limitations of existing motorized head lamp leveling device are: 1. High cost:- Because it uses stepper motor to adjust the inclination of headlamp, the cost of motorized systemls very high. 2. Noisy operation:- Because of electric motor, operation is always noisy. The level of noise depends on the skew ness of motor shaft with respect to headlamp. 3. Electric motor operates only if the voltage level at the sensing point is between 14% and 84% of supply voltage. 4. Unequal travel of cut off beam on LH and RH side of vehicle. This is because switch is always in the vicinity of the driver and hence the length of the cables connecting the motor and the switch is different on both sides. 5. Leveling operation is dependant on battery voltage level and combiswitch connectivity. 6. Motor construction is too complex and internal parts are not serviceable. Motor travel is restricted to 8mm. practically only 6.5mm travel is available for headlamp adjustment. Mechanically operated vehicular headlamp leveling devices are also known in the art. For example, US 5,459,646 (Sato) discloses a leveling device for a headlamp in which the illumination angle of the headlamp can be adjusted laterally by pivoting a reflector right to left with respect to a lamp body. The leveling device for measuring the lateral inclination of the reflector is held between the reflector and the lamp body. The leveling device comprises tubular holders, a sliding rod fitted into the holder and graduations provided between the sliding rod and the holder corresponding to the indicia. A holder fitting hole is formed in the tubular externally projecting portion, and the fixed holder is fitted into the holder fitting hole. Further, a pair of flanges formed on the fixed holder are fastened with screws to a boss projecting from the rear of the lamp body. The fixed holder is thus fixed to the lamp body. The pivotally moving member pivots laterally (about the vertical axis) with respect to the reference member, and the sliding rod longitudinally slides along the holder in association with the pivotal movement. The lateral pivoting movement of the pivotally moving member with respect to the reference member is proportional to the sliding movement of the sliding rod with respect to the holder, and the inclining movement of the pivotally moving member with respect to the reference member, that is, the amount of lateral shift of the illumination angle of the headlamp, appears as a corresponding variation in the relative graduations between the sliding rod and the holder. Consequently, it is possible to determine whether the lateral illumination angle of the headlamp is proper or not, and to determine the amount of deviation if the angle is improper. Moreover, the deviation can be corrected by adjusting, the relative graduations to the zero point. US 5, 506, 759 (Shirai et al.) discloses a vehicular headlamp having an aiming leveling device in which a support table is formed so as to project from a reflector which is tiltable relatively to a lamp body and a bubble tube support frame supporting a linear bubble tube is provided in provided such that one end of the support frame is fixed to the support table and the other end is held by a zero point adjusting means (a leaf spring like bubble tube support frame and an adjustment screw) used to adjust the position of the other end of the support frame in the up/down direction. The inclination of the bubble tube support frame (linear bubble tube) can be adjusted by rotating the zero point adjustment screw to thereby change the quantity of reflector-side projection of the zero point adjustment screw. The above prior arts has the disadvantage of numerous parts that are correlated which lead to easy wear and tear of the components. Also, accuracy of positioning these elements with respect to each other is tedious. Also, inertial loads caused by the motion accompanying the running the motor vehicle acts on the fastening components of the device, it damages these components and it becomes unable to properly perform its needed function. The proposed device will overcome the above said drawbacks. Summary of the Invention: The present invention relates to a novel vehicle headlamp leveling device and more particularly to a vehicle headlamp leveling device incorporating the principle of wedge action. The said device is divided into two units namely A & B. Unit A is the control unit mounted on the dashboard of the vehicle. Unit B is the headlamp unit mounted on a base plate. Said two units are connected by a push pull cable. The invention uses bevel gears, push/pull cable and related components to achieve the correction in cut off position using wedge action principle. The device according to the invention is activated by rotating a control knob located on the dashboard of vehicle, which pushes / pulls the push pull cable , with the help of bevel gears,mounted on the housing. The cable in turn activates the pair of wedges mounted on the base plate. This wedge action further causes the headlamp to tilt about the virtual axis X-X, formed by two screws mounted in the bottom of base plate. Objects of Invention : The main object of this invention is to provide mechanically operated Head lamp leveling device operation being independent of Electrical System. Another object of this invention is to provide a headlamp leveling device which is simple in construction, robust and economical. Yet another object of this invention is to provide a Headlamp leveling device having equal travel of cutoff beam on both left and right sides. Yet another object of this invention is to provide Headlamp leveling device to meet all regulatory requirements. Accordingly the invention relates to a head lamp leveling device comprising a control unit, a head lamp unit, a push pull cable comprising a first and second end said cable being connected to said control unit and head lamp unit, wherein said control unit comprises: a housing attached to the dashboard of the vehicle, said housing has a driver bevel gear and a follower bevel gear mounted thereon; said driver bevel gear is connected to a control knob through a guide shaft and said follower bevel gear is provided with a radial extension arm in to which one end of said cable is positively locked; the first end of said cable is adapted to pass through a wire guide locked on to the seat of said housing; said headlamp unit comprises: a base plate to support head lamp mounted on a head lamp rim; and an extension bracket extending out in a Z direction connected to said base plate, the second end of said push pull cable provided to lock into a slider and to pass through a further wire guide said further wire guide being positively locked onto said bracket; a first member is provided with an oblique face and is adapted to slide in a guide block which is mounted rigidly on to said base plate; a second member is connected to said head lamp rim through a spring and screw, said second member also comprising an oblique face juxtaposed with the oblique face of said first member. Brief Description of the Drawings: 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, Fig. 1 shows the mechanical Headlamp leveling device according to present aspects of the invention. Fig 2 shows the exploded view of Control Unit Fig.3a & 3b shows Slider and follower arrangement used in this invention. Fig.4. shows Head lamp in normal position Fig. 5 shows Head lamp in tilted position. Fig. 6 shows the conventional Headlamp leveling Device. Detailed Description of the Invention The invention will be explained in detail with reference to figures 1, 2, 3a, 3b, 4 and 5. Control Unit A The control unit (A) housing (1) is screwed on to the dashboard of the vehicle. The control unit housing (1) supports a control knob (3), guide shaft (2) and driver bevel gear (4) which form one unit and which can freely rotate in unison. The control knob (3) is locked onto one end of the guide shaft (2) and projects out of the dashboard. The driver bevel gear (4) is locked onto the other end of guide shaft (2). The housing (1) also supports a follower bevel gear (5) which freely rotates about the hinge shaft projecting out of housing (1) rear portion. The follower bevel gear (5) & driver bevel gear (4) form a bevel gear pair, which always remain in a meshed position. The follower gear (5) has a radial extension arm in to which the cable's end (6) is positively locked. The cable (6) passes through a wire guide (7a), which is locked onto the seat of housing (1). Any rotation of follower gear (5) gets converted in to reciprocatory motion of cable (6) by virtue of its guide (7a). Control unit A may have the similar provisions on another side of housing (1) to hold a second cable to be connected to the second headlamp of the vehicle. Head Lamp Unit B The head lamp unit (B) base plate (14) is screwed on to the fire wall of vehicle. It supports & mounts the headlamp (13) & the headlamp rim (18) by compression springs 11a, l1b, 11c and screws 12a, 12b, 12c. An extension bracket (15) is welded on to the base plate (14) & extends out of it in the Z direction. This helps in straightening the cable (6) before it enters UNIT B. The cable (6) is guided by wire guide (7b), which is positively locked on bracket (15) said cable (6) passes through wire guide (7b) and locks in to the slider (8). The second end of the cable (6) is firmly joined to a cylindrical pin to insert into a groove provided in the slider (8). The slider (8) has a groove which houses a spring (16) and a spherical ball (17) adapted to slide on a said curvilinear groove of a guiding block (9) and to retain a particular position. The slider (8) has two ribs on the inner side of its walls and the follower (10) has two corresponding grooves 10(a) on the side wall to prevent lateral movement of the follower (10). Slider (8) is free to slide up & down in the Z direction inside the guiding block (9). Throughout its travel the slider (8) stays guided in the slots of guiding block (9). The guiding block (9) is mounted rigidly on to the base plate (14). The guiding block (9) has a stepped curvilinear groove and a square projection on its back that locks it against any relative motion or rotation on base plate (14). Fig 3a, (4) & fig (5) shows cut sections of head lamp unit of fig 1 , wherein slider (8) houses retainer spring (16) and spherical ball (17) that ensures its locking in two positions, namely normal & tilted, in the grooves of guide block (9). The slider (8) has at least two spherical projections, perpendicular to the sliding face of follower, on inner face. The sliding face of the slider (8) is oblique, preferably at 45 degrees. The Follower (10) also has an oblique face, which abuts with the oblique face of slider (8) and thus it forms a wedge pair. The follower (10) face opposite to the slider face is provided with tapping. Also the follower (10) has oblique slots on its sides. These slots allow the spherical ball (17) of slider (8) to move through the slot and whenever the slider (8) is pushed or pulled by the cable (6) the follower (10) is pushed forward and backward in perpendicular direction. The rim (18) carrying headlamp (13) is mounted on to the base plate (14) by three spring loaded screws (12a, 12b, 12c). The top screw is screwed into the follower 10. is the slider (8) is free to move longitudinally, causing the headlamp to tilt about the virtual axis X-X formed by two screws mounted in the bottom of base plate 14. Therefore, whenever the control knob (3) is rotated the bevel gear (5) rotates and this rotatory movement in turn exerts a pull force on the cable (6). Consequently, this cable transfers the motion positively to the slider (8). The slider (8) thus gets pulled up in the positive Z direction. This movement of the slider causes the follower (10) to be pushed in the forward direction due to the wedge action, and in turn causes headlamp (13) to tilt about the virtual hinge axis, X-X, formed by bottom screws 12b & 12c. Hence the vertical orientation of dipped beam of headlamp is achieved. Head lamp (13) along with rim (18) is supported on a base plate (14) with the help of screws (12b, 12c) and springs (11b, 11c) to achieve headlamp movement in horizontal direction. 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) A head lamp leveling device comprising a control unit (A), a head lamp unit (B), a push pull cable (6) comprising a first and second end said cable being connected to said control unit (A) and head lamp unit (B), wherein said control unit (A) comprises: a housing (1) having a driver bevel gear (4) and a follower bevel gear (5) mounted thereon; said driver bevel gear (4) is connected to a control knob (3) through a guide shaft (2) and said follower bevel gear (5) is provided with a radial extension arm in to which one end of said cable (6) is positively locked; the first end of said cable (6) is adapted to pass through a wire guide (7a) locked on to the seat of said housing (1); said headlamp unit (B) comprises: a base plate (14) to support head lamp (13) mounted on a head lamp rim (18); and an extension bracket (15) extending out in a Z direction connected to said base plate (14), the second end of said push pull cable (6) provided to lock into a slider (8) and to pass through a further wire guide (7b) said further wire guide (7b) being positively locked onto said bracket (15); a first member (8) is provided with anoblique face and is adapted to slide in a guide block (9) which is mounted rigidly on to said base plate (14); a second member (10) is connected to said head lamp rim (18) through a spring (11a) and screw (12a), said second member (10) also comprising an oblique face juxtaposed with the oblique face of said first member (8). 2) The device as claimed in claim 1, wherein the said first member is a slider and said second member is a follower; said slider being adapted to be pulled or pushed in the positive or negative Z direction depending on the pull or push motion experienced by the cable in response to the rotation of the control knob; said slider adapted to transfer the motion to the follower by wedge action and by virtue of their configuration and position relative to each other. 3) The device as claimed in claims 1 and 2 wherein the said control unit (A) has similar provisions on the other side of housing (1) to hold a second cable to be connected to a second head lamp in a vehicle. 4) The device as claimed in claim 1 to 3 where in said guide block (9) has a stepped curvilinear groove and a projection on its back that locks it against any relative motion or rotation on base plate (14). 5) The device as claimed in claim 1 to 4 where in said slider (8) comprises a groove which houses a spring (16) and a spherical ball (17) to slide on a said curvilinear groove of said guide block (9) and to fix in a particular position. 6) The device as claimed in any of the claims 1 to 5 wherein the slider (8) has at least two ribs on the inner side of its walls and the follower (10) has two corresponding grooves on the sidewall to prevent lateral movement of the follower (10). 7) The device as claimed in claim 1 wherein the said slider (8) has at least two spherical projections, perpendicular to the sliding face of follower, on its inner face. 8) The device claimed in any one of the preceding claims wherein the second end of the cable (6) is firmly joined to a cylindrical pin to insert into the groove provided in a slider (8). 9) The device as claimed in claim 1 or 2 wherein the head lamp (13) along with rim (18) is supported on a base plate (14) with the help of screws (12b, 12c) and springs (11b, 11c) to achieve headlamp movement in horizontal direction. 10) The head lamp leveling device substantially as here in described with reference to figures 1 to 5 of the accompanying drawings Dated this 20th day of February 2007 TATA MOTORS LIMITED By their Agent and Attorney (KARUNA GOLERIA) of DePENNING & DePENNING

Documents:

341-mum-2007-abstract(27-5-2008).doc

341-mum-2007-abstract(27-5-2008).pdf

341-mum-2007-abstract.doc

341-mum-2007-abstract.pdf

341-mum-2007-cancelled pages(27-5-2008).pdf

341-mum-2007-claims(granted)-(20-2-2007).doc

341-mum-2007-claims(granted)-(20-2-2007).pdf

341-mum-2007-claims.doc

341-mum-2007-claims.pdf

341-mum-2007-correspondence(27-5-2008).pdf

341-mum-2007-correspondence(ipo)-(29-8-2007).pdf

341-mum-2007-correspondence-received.pdf

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

341-mum-2007-drawing(27-5-2008).pdf

341-mum-2007-drawings.pdf

341-mum-2007-form 1(20-2-2007).pdf

341-mum-2007-form 18(10-4-2007).pdf

341-mum-2007-form 2(granted)-(20-2-2007).doc

341-mum-2007-form 2(granted)-(20-2-2007).pdf

341-mum-2007-form 3(20-2-2007).pdf

341-mum-2007-form 9(10-4-2007).pdf

341-mum-2007-form-1.pdf

341-mum-2007-form-2.doc

341-mum-2007-form-2.pdf

341-mum-2007-form-26.pdf

341-mum-2007-form-3.pdf

341-mum-2007-power of attorney(20-2-2007).pdf

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