FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003


COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
An Apparatus For Mounting Linear Variable Displacement Transducer On Vehicle For Measuring Wheel To Body Displacement
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
Mithun Chaskar, Akbar Attar, Shailesh Badadhe,
Chavan Girish, Santosh Gosavi
and V G Bhalerao
All are 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 specification particularly describes the invention and the manner
in which it is to be performed.


FIELD OF INVENTION
The present invention relates to measurement of wheel to body displacement for vehicle and more particularly it relates to an apparatus for mounting linear variable displacement transducer (LVDT) on vehicles for measuring wheel to body displacement at front and rear wheels.
BACKGROUND OF INVENTION
The wheel to body displacement measurement is important for the assessment of structural durability of the vehicle. For measuring the wheel to body displacement of a vehicle the linear variable displacement transducer (LVDT) is mounted on a vehicle.
The conventional method of Fitment of the linear variable displacement transducer (L.V.D.T) on the vehicle suffers from the following disadvantages; it doesn't provide free movement in the vertical direction, there is no provision of bearing support and counter adjustment in case of misalignment, for angular movement of the front wheel of the vehicle in the horizontal plane, there is no automatic correction for additional displacement.
Due to steering movemeni there is relative displacement between BIW sensor attachment point to wheel center, even if there is no relative movement in vertical direction, still the wheel center moves slightly BIW point.
In order to address the above disadvantages, an apparatus for mounting linear variable displacement transducer (LVDT) for measuring wheel to body displacement has been developed. This apparatus reduces the fitment time due to ease of adaption.
OBJECTS OF INVENTION
The main object of this invention is to provide an apparatus for mounting linear variable displacement transducer (LVDT) on vehicles for measuring wheel to body displacement.


Another object is lo provide a fixture for mounting linear variable displacement transducer (LVOT) on vehicles for measuring wheel to body displacement which simple fitment arrangement to save instrumentation time with improved accuracy and reliability of measurement exercise without damaging sensor or vehicle peripherals.
BRIEF DESCRIPTION OF INVENTION
In accordance with the present invention, an apparatus for mounting linear variable displacement transducer (LVDT) on vehicles for measuring wheel to body displacement Comprises; wheel adaptor for mounting on vehicle, an extension shaft with bearing mounted hub on it, fixing mechanism on vehicle body and counter act mechanism to ensure error free data of displacement sensors,
STATEMENT OF INVENTION
Accordingly the present invention discloses an apparatus for mounting linear variable displacement transducer (LVDT) on vehicles for measuring wheel to body displacement comprising: a wheel to body mounting fixture arrangement comprising:
a wheel adaptor provided to be mounted on a wheel rim, said wheel adaptor comprising a hub mounted on a hub shaft through a hub bearing;
a sensor mounting bracket;
a sensor piston arrangement for adjusting measurement range;
a rod arrangement having a length more than the total travel of wheel in bump and rebound condition; wherein
said wheel to body mounting fixture arrangement is fitted on vehicle body with mounting members provided on a bracket arrangement.


BRIEF DESCRIPTION OF DRAWINGS
Figure-01 shows the wheel adaptor assembly,
Figure-02 shows the wheel to body mounting fixture arrangement.
Figure-03 shows the steering correction mechanism.
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.
Now referring to figure-01 and 02In accordance with the first embodiment of the present invention, said apparatus comprises; wheel adaptor assembly, wheel to body mounting fixture arrangement.
said wheel adaptor assembly comprises; a wheel cup (01) for mounting a hub shaft (02), a hub (03) is provided therein and mounted on said hub shaft (02) , circlips (05,06 ) for retaining said hub (03) on said hub shaft (02),
Said wheel cup (01) for mounting hub shaft (02) with the help of bolts (04), a hub (0.3) is mounted on the said hub shaft (02) through bearing (07).The circlips (05,06) are provided to retain the said bearing (07) and the said hub (03) on the said hub shaft (02). The assembly is mounted on the wheel rim with wheel bolts. The lower ball end of the sensor piston (12) of linear variable displacement transducer (L..V.D.T.) is mounted on the bearing hub with the help of said adaptor shaft (09), The upper ball end of the said sensor piston (12) of L.V.D.T.is attached with the eye point (14) of the fork which is mounted with the fixture on the body of vehicle.
Referring to Figure-02, which shows the wheel to body mounting fixture arrangement for restricting the sensor to move from its position due to free movement of bearing load in radial direction. Said wheel to body mounting fixture


arrangement comprises; a wheel adaptor (08) for mounting on wheel of vehicle, adaptor shaft (09) is provided to hold the said LVD17 censor, dust proof bearing (10) to provide frictionless rotation, sensor mounting bracket (11), sensor piston (12) for adjusting measurement range, aluminum rod (13), eye point (14) is provided for holding said sensor piston (12), plastic ring (16) for heading said aluminum rod (13) vertically by keeping height of rod (15) more than total travel of wheel in bump and rebound condition, whole assembly is fitted on vehicle body with the help of mounting plate (17) and plate member (18) provided on 'J' shaped bracket arrangement (19).
Said Wheel adaptor (8) is placed on the wheel with universal mounting PCD (pitch circle diameter) arrangement. One of hole of said adaptor is kept open. Inner diameter (ID) of hole is kept more than bolt outer diameter so that it passes through the bolt and without removing, all 4 bolts it can be fitted- Said adaptor shaft (9) which is made up of light weight aluminum to hold the LVDT/ sensor . Said dust proof bearing (10) is specially devised not to provide minimum friction while rotating. Said bearing (10) separates wheel end from the sensor end. Sensor is mounted on the bearing with suitable sensor mounting bracket (11). All sensors are provided with swivel joint. To restrict the movement of sensor, it is fitted to the bearing bracket with suitable number of washers. Said sensor piston (12) provided for facilitating adjustment of measurement range, said aluminum rod (13) is fixed at the sensor end of said bearing with spring steel (13') in between said bearing and said aluminum rod (13).
Said Eye point (14) is provided for holding the eye point of said sensor piston (12) with said T shaped bracket (19). Said spring steel is used to avoid shock loads in all the three directions experienced during on road trials- Said Aluminum rod (13) is held vertically using plastic ring (16) and the height of the rod (15) is kept more than the total travel of the wheel in bump and rebound condition. This mechanism restrict sensor to move only in vertical direction instead of any other direction. The whole sensors is luted to the said J shaped mounting bracket (19) which can accommodate


the displacement sensor and can give freedom to move the sensor position in 30 deg radial direction.
Said Plate member (18) is provided on said 'J' shaped bracket (19) for fixing whole assembly to vehicle body.
The complete assembly is fitted on the vehicle body using T shaped bracket arrangement (19). The said J shaped bracket is provided with .plurality of holes arranged vertically to make the sub structure more standardized and usable for any measurements applications. The said plate member (18) is fixed to the vehicle body with additional mounting plate (17). To avoid direct mechanical contact with vehicle body the said plate member (18) and mounting plate (17) are covered with rubber. ir shaped is configured to adapt all possible size and shape of automotives.
The first embodiment of the present invention works well for no steering movement application.
Now referring to figure-03, In accordance with second embodiment of the present invention, said apparatus comprises; a adaptor assembly , wheel to body mounting fixture arrangement and steering correction mechanism , wherein said steering correction mechanism comprises; at least two plastic rings (20), bearing (21) , a cam arrangement (22), sensor reference point (23) and suspension arrangement (24) for correcting relative displacement between vehicle body sensor attachment point and wheel centre due to steering movement which automatically adjust reference point on vehicle body and nullifies steering angle error and resultant of displacement transducer will not change or show any change in reading.
Said two plastic rings (20) are provided for guiding the aluminum rod (13, 15) which enables the mechanical adaptation to quantify and differentiate the linear motion and steering movement. In case of steering movement there will be definite angular movement of said plastic rings (20). The whole mechanism is rested upon a bearing


(21) and cam arrangement (22). Said bearing (21) and cam arrangement (22) are mounted on said 'J shaped bracket arrangement (19). When there is a steering movement, the rotary action will rotate the said cam (22) in turn the sensor mounting reference point (23) will move down depending upon the steering movement. The said cam (22) is devised and calibrated to act upon steering movement. The said mounting reference point (23) is rested upon suspension arrangement (24). This arrangement automatically adjust reference point on vehicle body and nullifies steering angle error and resultant of displacement transducer will not change or show any change in reading.
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 apparatus for mounting linear variable displacement transducer (LVDT)
on vehicles for measuring wheel to body displacement comprising:
a wheel to body mounting fixture arrangement comprising:
a wheel adaptor provided to be mounted on a wheel rim, said wheel adaptor comprising a hub mounted on a hub shaft through a hub bearing;
a sensor mounting bracket;
a sensor piston arrangement for adjusting measurement range;
a rod arrangement having a length more than the total travel of wheel in bump and rebound condition; wherein
said wheel to body mounting fixture arrangement is fitted on vehicle body with mounting members provided on a bracket arrangement.
2. An apparatus as claimed in claim 1, further comprising
a steering correction mechanism comprising:
at least two plastic rings for guiding said rod arrangement;
a bearing and cam arrangement calibrated to act upon steering movement;
a sensor mounting reference point movable depending upon the steering movement; and
a suspension arrangement for correcting relative displacement between LVDT attachment point and wheel centre due to steering movement.
3. The apparatus as claimed in claim 1 or 2, wherein said wheel adaptor comprises a wheel cup for mounting said hub shaft and circlips to retain said hub bearing and said hub on said hub shaft,
4. The apparatus as claimed in claim 1 or 2, wherein said hub shaft is provided to hold said LVDT.


5. The apparatus as claimed in claim 1, wherein a plastic ring is provided for vertically holding said rod.
6. The apparatus as claimed in claim 5, wherein said rod is preferably made of aluminium.
7. The apparatus as claimed in claim 1 or 2, wherein an eye point is provided for holding said sensor piston in position.
8. The apparatus as claimed in claim 1 or 2, wherein said bracket arrangement is preferably a 'J' shaped bracket arrangement to adapt all possible size and shape of vehicles.
9. The apparatus as claimed in claim 1 or 2, wherein said LVDT is provided with a swivel joint and a plurality of washers are provided to restrict the movement of said LVDT.
10. The apparatus as claimed in claim 6, wherein said aluminum rod is fixed at the sensor end of said hub bearing with spring steel in between said hub bearing and said aluminum rod.
11 The apparatus as claimed in claim 1 or 2, wherein said sensor mounting bracket is provided to accommodate the LVDT sensor and gives freedom to move the sensor position in a 30 deg radial direction.
12. The apparatus as claimed in claim 8, wherein said 'J' shaped bracket is provided with plurality of holes arranged vertically for adaptability.


"13. An apparatus for mounting linear variable displacement transducer (LVDT) on vehicles for measuring wheel to body displacement substantially as herein above described and as illustrated in accompanying drawings.
Dated this 30th day of March 2009

TATA Motors Limited
By their Agent & Attorney

(Karuna Goleria) of De PENNING & De PENNING