COMPLETE AFTER PROVISIONAL
LEFT ON 30 NOV2005
FORM 2
THE PATENTS ACT, 1970 (39 of 1970)
As amended by the Patents (Amendment) Act, 2005
&
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2005
COMPLETE SPECIFICATION (See section 10 and rule 13)
TITLE
Display device for indicating measured values of operational parameter of an automotive vehicle
INVENTORS
a)Names : Ahir Prashant Raghunath and Adhikari Rahul Prafullachandra b)Address : Bajaj Auto Limited, Akurdi, Pune 411035, Maharashtra, India c)Nationality : both Indian Nationals
APPLICANTS
a) Name : Bajaj Auto Limited
b)Address : Akurdi, Pune 411035, Maharashtra, India
c) Nationality : an Indian Company
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:


FIELD OF INVENTION
This invention relates to a display device for indicating measured values
of operational parameter of an automotive vehicle.
PRIOR ART
Values of operational parameters of automotive vehicles like vehicle speed, engine shaft RPM, engine oil pressure or quantity or level of fuel in the fuel tank keep changing during running of the vehicles and are measured by analogue measuring instruments like speedometers, engine shaft RPM meters, oil pressure gauges or fuel gauges, as the case may be, and the measured values are indicated by display devices mounted on the handle bar in the case of two wheeler vehicles or dash board in the case of 3 or 4 wheeler vehicles. A display device essentially comprises a graduated dial graduated in terms of the units of the respective values to be indicated and provided with a transparent material cover. A pointer is disposed above the dial within the cover and fixed to the rotor of the respective measuring instrument. The rotor is disposed in a hole in the dial and rotates responsive to changes in the above values as measured and input by the respective measuring instruments. The pointer rotates
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with the rotor and indicates the corresponding values on the dial. Lamps are provided below the dial to illuminate the dial. A lit needle arrangement is also provided to illuminate the pointer. The lit needle arrangement is complicated in design and construction. Due to the lit needle arrangement being complicated in design and construction, there are also chances of errors occurring in the design and/or manufacture of the lit needle arrangement and the pointer being insufficiently or excessively lit causing problems for the reader to read the values clearly on the dial, especially in the night. The pointer has certain width and occupies corresponding area on the dial which is wider than the width of the graduations on the dial. Therefore, the pointer does not point to or indicate the exact corresponding reading on the dial. This gives rise to inaccuracy in the readings on the dial as observed by a reader. Due to the pointer being at a distance above the dial, there is always parallax effect during reading and depending upon the direction of viewing of the graduations on the dial, the observed reading will be more or less than the actual or exact reading resulting in inaccuracy in the readings.
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OBJECTS OF INVENTION
An object of the invention is to provide a display device for indicating measured values of operational parameter of an automotive vehicle, which eliminates the pointer and lit needle arrangement and is simple in design and construction and which enables a reader to read the values clearly and accurately on the dial.
Another object of the invention is to provide a display device for indicating measured values of operational parameter of an automotive vehicle, which eliminates the parallax effect and enables a reader to read the values clearly and accurately on the dial.
Another object of the invention is to provide a display device for indicating measured values of operational parameter of an automotive vehicle, which indicates to the reader how close a value read on the dial is to a major reading on the dial.
Another object of the invention is to provide an automotive vehicle comprising the display device.
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DETAILED DESCRIPTION OF INVENTION.
According to the invention there is provided a display device for indicating measured values of operational parameter of an automotive vehicle, the display device being adapted to be mounted on the handle bar of a 2 wheeler vehicle or dashboard of a 3-or 4-wheeler vehicle and comprising a graduated dial graduated in terms of the respective values to be indicated, a transparent material cover provided over the dial and a laser source disposed above the dial and mounted on the rotor of an analogue measuring instrument of the vehicle, the rotor being disposed in a hole in the dial and provided with a non-transparent material closure which is formed with a narrow slit, the laser source being powered by a regulated DC voltage and adapted to illuminate and indicate the graduations on the dial.
According to the invention there is also provided an automotive vehicle comprising the display device.
Preferably, the dial is provided with a depression and the laser source is disposed in the depression.
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Preferably, the transparent material cover is provided with a L-shaped flange in cross-section at the edge thereof, the flange being formed with mounting lugs.
According to an embodiment of the invention, the major graduations on the dial are highlighted with marker members.
According to an embodiment of the invention, the regulated DC voltage is derived by connecting the laser source to the magneto of the vehicle through a voltage regulator and AC to DC converter.
According to another embodiment of the invention, the regulated DC voltage is derived by connecting the laser source to a battery in the vehicle through a voltage regulator.
According to an embodiment of the invention, the dial is graduated in terms of units of speed and the display device is mounted on the housing of a speedometer with the laser source mounted on the rotor of the speedometer.
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The following is a detailed description of the invention with reference to the drawings accompanying the provisional specification, in which :
Fig 1 is plan view of a display device for indicating measured values of operational parameter of an automotive vehicle according to an embodiment of the invention;
Fig 2 is cross-section at A-Ain Fig 1;
Fig 3 is cross-section of a display device for indicating measured values of speed of an automotive vehicle mounted on a speedometer according to an embodiment of the invention;
Fig 4 is diagramatic representation in blocks of the connection of the laser source of the display device of Figs 1 and 2 or Fig 3 to the magneto of the automotive vehicle; and
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Fig 5 is diagramatic representation in blocks of the connection of the laser source of the display device of Figs 1 and 2 or Fig 3 to a battery in the automotive vehicle.
The display device 1 as illustrated in Figs 1 and 2 of the drawings accompanying the provisional specification, comprises a graduated dial 2 graduated (graduations marked 2a) in terms of the values to be indicated. For instance, in case speed variations of an automotive vehicle are to be indicated, the dial is graduated in terms of kms or miles / hr; in case RPM of engine shaft of the vehicle is to be indicated, the dial is graduated in terms of RPM; in case engine oil pressure of the engine of the vehicle is to be indicated, the dial is graduated in terms of kg / cm or pounds /sq inch; or in case level or quantity of fuel in the fuel tank of the vehicle is to be indicated, the dial may be graduated, for example, as empty, half, full or reserve. A transparent material cover 3 is provided over the dial. The edge of the cover defines a L-shaped flange 3 a. The cover is made of transparent material such as acrylic or poly carbonate. The L-shaped flange 3a of the cover is provided with mounting lugs 3b, 3c and 3d. The cover is mounted on the handle bar (not shown) of a 2 wheeler vehicle or dashboard (not
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shown) of a 3- or 4- wheeler vehicle by securing screws (not shown) through fixing holes 3e provided in the lugs with the dial located against the handle bar or dash board, as the case may be, such that dial remains fixed in position. 4 is a laser source disposed in a depression 2e at the center of the dial and mounted on the rotor 5 of an analogue measuring instrument (not shown) of the vehicle. The rotor is disposed in a hole 2c at the center of the dial and provided with a non-transparent material closure 6 which is formed with a narrow slit 6a. The closure may be made of non-transparent material such as acrylonitrile butadiene styrene. The laser source is connected to the magneto 7 of the vehicle through a voltage regulator 8a and AC to DC converter 9 (Fig 4 of the drawings accompanying the provisional specification). Alternatively, the laser source is connected to a battery 10 in the vehicle through a voltage regulator 8b (Fig 5 of the drawings accompanying the provisional specification). The voltage regulator 8a or 8b regulates the voltage from the magneto or battery, as the case may be, to a voltage sufficient to light the laser source, say to the order of 5 volts. The AC to DC converter 9 converts the AC voltage from the magneto to DC voltage. In a case where the laser source is powered by the magneto, when the ignition switch (not shown) of the vehicle is
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turned on and the engine is idling the laser source is also turned on and a thin laser beam beams out through the slit in the closure and illuminates and points to the zero reading on the graduated dial. When the vehicle starts moving and the values of the operational parameter in respect of which the dial is graduated change, the rotor whose rotational movement is a measure of the change of value, rotates about the dial by a corresponding angle and the laser beam also rotates with the rotor by the same angle and illuminates and points to the corresponding graduation on the dial. The graduation on the dial is thus indication of the measured value of the respective operational parameter. In a case where the laser source is powered by the battery and when the ignition switch is turned on, the laser source is also turned on and the laser beam travelling out from the laser source through the slit in the closure illuminates and points to the zero reading on the graduated scale. As the vehicle starts moving and the values of the operational parameter in respect of which the dial is graduated changes, the rotor and laser source rotate correspondingly and the laser beam illuminates and points to and indicates the respective graduation on the dial. The dial is provided with marker members 11 at major graduations on the dial. The marker members help the reader of the values on the dial to

identify the closeness of the observed values to the major readings. For instance, if a dial is graduated in terms of speed units of Km / hr, a marker member is provided at say graduation 50 and the observed value is 45, the reader can easily relate the closeness of the observed value to 50 and take measures to reduce or increase the speed of the vehicle by accelerating or decelerating the vehicle, as may be required.
In Fig 3 of the drawings accompanying the provisional specification, the display device 1A of the invention comprises a dial 2 graduated in terms of units of speed namely kms or miles / hr. The display device is shown as mounted on the housing 12 of a speedometer 13. The speedogear (not shown) of the speedometer mounted on the front wheel (not shown) or gear box (not shown) of an automotive vehicle transmits the rotational speed of the wheel to the adapter 14 of the speedometer through the cable (not shown) of the speedometer connecting the speedogear to the adapter. This causes the adapter and in turn the rotor to rotate proportionately in known manner. The laser source rotates with the rotor and the laser beam travelling out through the slit in the closure points to and illuminates a corresponding graduation of speed on the dial so as to facilitate reading of the measured
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value of speed on the dial. The lamps illuminating the dial of the speedometer are marked 15a and 15b. The various other parts of the speedometer have not been marked and their functioning have not been explained in detail as such parts are not necessary for understanding the invention.
According to the invention the pointer and lit needle arrangement have been eliminated. The display device of the invention is, therefore, simple in design and construction. The laser beam is very thin almost corresponding to the width of the graduations on the dial. It illuminates and points to the respective graduations exactly on the dial. The laser beam also eliminates the parallax effect. Therefore, the measured values of operational parameters of automotive vehicles can be easily read on the dial very clearly and accurately. Besides, the marker members indicate to the reader the closeness of the observed value to the major readings on the dial.
The transparent material cover may be of a different geometry / construction and may be adapted to be mounted on the handle bar of a 2 wheeler vehicle or dashboard of a 3 or 4 wheeler vehicle in a different


manner instead of lugs and screws. The marker members are optional. Such variations of the invention are to be construed and understood to be within the scope of the invention.


We claim
1. A display device for indicating measured values of operational parameter of an automotive vehicle, the display device being adapted to be mounted on the handle bar of a 2 wheeler vehicle or dashboard of a 3-or 4-wheeler vehicle and comprising a graduated dial graduated in terms of the respective values to be indicated, a transparent material cover provided over the dial and a laser source disposed on the dial and mounted on the rotor of an analogue measuring instrument of the vehicle, the rotor being disposed in a hole in the dial and provided with a non-transparent material closure which is formed with a narrow slit, the laser source being driven by a regulated DC voltage and adapted to illuminate and indicate the graduations on the dial.
2. A display device as claimed in claim 1, wherein the dial is provided with a depression and the laser source is disposed in the depression.
3. A display device as claimed in claim 1 or 2, wherein the transparent material cover is provided with a L-shaped flange in cross-section at the edge thereof, the flange being formed with mounting lugs.
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4. A display device as claimed in any one of claims 1 to 3, wherein the major graduations on the dial are highlighted with marker members.
5. A display device as claimed in any one of claims 1 to 4, wherein the regulated DC voltage is derived by connecting the laser source to the magneto of the vehicle through a voltage regulator and an AC to DC converter.
6. A display device as claimed in any one of claims 1 to 4, wherein the regulated DC voltage is derived by connecting the laser source to a battery in the vehicle through a voltage regulator.
7. A display device as claimed in any one of claims 1 to 5 for indicating speed of an automotive vehicle wherein the dial is graduated in terms of units of speed and the display device is mounted on the housing of a speedometer with the laser source mounted on the rotor of the speedometer.


8. An automotive vehicle comprising a display device as claimed in any one of claims 1 to 7.
9. A display device for indicating measured values of operational parameter of an automotive vehicle as herein described with reference to Figs 1,2 and 4 or Figs 1,2 and 5 or Figs 3 and 4 or Figs 3 and 5 of the drawings accompanying the provisional specification.
Dated this 30th day of November 2005
(Jose M A)
of Khaitan & Co
Agent for the Applicants