FORM 2
THE PATENT ACT 1970
&
The Patents Rules, 2003
PROVISIONAL / COMPLETE SPECIFICATION (See section 10 and rule 13)
1. TITLE OF THE INVENTION
A Multi-gauging system for vehicle chassis.
2. APPLICANT
(a) NAME : MAHINDRA & MAHINDRA LTD
(b) NATIONALITY : An Indian Company registered under the
Companies Act, 1956
(c) ADDRESS : R&D Centre, Auto sector,
89, M.I.D.C, Satpur, Nashik- 422007 Maharashtra State, India.
3. PREAMBLE TO THE DESCRIPTION

The following specificarion describes the invention.

COMPLETE
The following specification particularly describes the invention and the manner in which it is to be performed.

Technical Field oi Invention:
The present invention relates to the multi-gauging system for vehicle chassis. More particularly the present invention is related about online system for checking and measurement of chassis dimensions and method thereof.
Background and Prior Art:
Most inspections in automobile applications are heavily reliant on attribute gauging or the CMM. Although attribute gauging is quick, it is unable to provide actual dimensional values. Also, CMM/ optical LEICA checking provides very high accuracy, but is not feasible for 100% inspection of parts in a mass production scenario. The following paragraphs detail the short comings of the conventional methods of checking and subsequently help to highlight the aptness of the proposed gauging system in the mass production scenario.
In conventional attribute gauges no dimensional interpretation of the data is possible. Data base generated from the inspection is of no future use and the accuracy of the inspection process is greatly affected by the appraiser.
In case of CMM & Optical LEICA checking only Sampling type inspection of the frame is possible. The process is too much time consuming that data collection for hardly 1 Frame/Day is possible. In case of Dimensional Issues, the tooling needs to be rechecked. The handling of frame on CMM & LEICA is difficult but the dimensional data is available once a day that too without delay.
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US Patent No. 4165567 discloses checking and measurement device for automobile chassis, comprising measurement scale carriers which are adjustable in correspondence with the spatial position of measurement points in a vehicle chassis. Each one of the measurement scale carriers consists of a transverse arm disposed for measuring in the transverse direction of the chassis, the arms having, at each end portion, a guide for a releasable measurement rod which may be connected to each respective arm end portion for measuring in the vertical direction of the chassis and is of adjustable length, which has means for pivotal suspension of the measurement rod in a chassis measurement point and means for adjusting the measurement rod in the transverse direction of the arm for measuring in the transverse direction of the chassis. The checking and measurement device is suspendable by means of these measurement rods in its entirety in measurement points in the chassis and is furnished with a device for measuring in longitudinal direction of the chassis.
In this system, accurate measurement is not possible because of least count accuracy, linear scale and parallel axis error. Checking of the LH/RH bracket on the chassis which having same function but co-ordinate is opposite, provision for this kind of checking is not available in this invention. The analysis and the direct parametric readings are not available. This is some sort of different measurement device which is not comparable with the features and concept incorporated in the proposed invention.
US Patent No. 5341575 describes an apparatus to gather, display, and/or print vehicle chassis measurement data for accurate repair of collision
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damaged vehicles. The coordinates of a plurality of datum check points for a vehicle chassis is obtained relative to X, Y and Z coordinates relative to a given horizontal datum plane and/or a vertical datum plane and used primarily to prepare specification drawings for vehicle chassis to be used by body and frame alignment operators to correct collision damage.
This patent specifically is directed to straightening and reforming vehicle bodies, frames and other part of the damaged or misaligned vehicle back to their dimension and specification that have been precisely laid down by the vehicle manufacturer. This method is not applicable for the production process. This method is for service station to repair the vehicle chassis.
US patent No. 4319402 discloses chassis gaging system for measuring the position of reference locations on an automobile chassis with respect to the standard location at proper configuration. The gaging system comprises a locator bed with a replaceable grid paper thereon which has standard locations marked on the grid paper. Adjustable length plumb lines are supported from the reference locations and, when the chassis is in correct configuration, the plumb bobs point to the location marks on the grid paper. The locator bed can be removed for chassis bending, but the plumb lines and their bobs can remain in place during the bending operation.
This patent does not talk about a provision to check the SC/CC parameter of chassis. This system checks only the straightness or to check the bent due to crash or during the transportation. The analysis and the direct parametric readings are not available. The procedure is time consuming often lead to
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over working / reworking of the chassis material due to trial and error method and the absence of the gaging hardware during the actual bending operation.
Deficiencies of Prior Art:
• Conventional methods such as Attribute & CMM/ optical LEICA checking have several constraints, the main being appraiser dependency and process time, amongst others
• The analysis and the direct parametric readings are not possible.
• The methods disclosed in prior art are for service station to repair the vehicle chassis and not applicable for the production process.
• The prior art patents are directed to straightening and reforming vehicle bodies, frames and other part of the damaged or misaligned vehicle as per the specifications laid down by vehicle manufacturer.
• None of the prior art patent talk about a provision to check the SC/CC parameter of chassis.
• The procedures in prior art are time consuming often lead to over working / reworking of the chassis material due to trial and error method.
Objects of the present Invention:
1. To have an online gauging system to check the SC/CC parameters of chassis frame assembly in a mass production scenario.
2. To check the required parameters within low tact/ production tact.
3. To record the data in a comprehensive data base that can be referred as and when required.
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4. To generate real time SPC data of all & dimensions for analysis and further control.
5. To eliminate Appraiser's intervention for inspection.
6. To make the data available online for keeping a track of the process from a remote location
Statement of present invention: Accordingly the present invention provides a multi-gauging system for vehicle chassis for checking the dimensions comprises a platform for mounting the chassis to be inspected; the said platform is having a pair of master units to locate the said chassis on the said platform base plate as per the tool design coordinates; plurality of gauges are mounted on the said base plate at various locations for inspecting check points of chassis to be inspected; the said gauge is having a bush, mounted on the sliding block fixed to the cross slide which moves in x-axis and /or y-axis when an individual pin is inserted through the said check points, if the said check point is not exact location on chassis; a pair of potentiometer is fixed to said gauges which is having spring biased plunger self equalising and said plunger is resting against the individual sliding blocks; the said potentiometer is electrically connected to as an input to the data decoder and the output of the said data decoder is inputted to the data analyser which is configured to analyze the data and check it with the set standards and process it to the output terminal.
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Description of figures:
Fig. 1(a): Plan (Top view) of multi-gauging system with chassis mounted thereon as disclosed in the present invention
Fig. 1(b): Elevation (Front view) of multi-gauging system with chassis mounted thereon as disclosed in the present invention Figure 2 shows plan of a gauge employed in multi-gauging system; Figure 3 shows the front view of a gauge employed in multi-gauging system of the present invention;
Figure 4 shows cross section of a gauge along D-D in figure 2; Figure 5 shows the flow chart of the multi-gauging system.
Description of the Invention:
The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and approaches are overcome by the present invention as described bellow in the preferred embodiment.
This invention is illustrated in the accompanying drawings, through out which like reference letters indicate corresponding parts in the various figures.
The chassis frame assembly is an integral part of the vehicle. It not only affects structural integrity, but also handling of the overall vehicle. Hence, it is essential that the Significant/ Critical characteristics of the same be maintained within the permissible limits. The gauging system as disclosed herein permits quick and accurate checking of required parameters and accordingly qualifies the same as defective or not. This is essential in maintaining reliability for assembly line quality concerns for chassis. Also,
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reliability issues experienced on field by the end users of the vehicle can be traced back to the chassis frame, and these issues can be controlled by incorporating the same in the qualifying gauge. The custom built software allows quick, real time analysis of data, permitting process variations, if any, to be detected well in time.
The present invention "a Multi-gauging system for vehicle chassis" is now described with reference to accompanying drawings. Referring to figures 1 to 5 Multi-gauging system (1) comprises of number of gauges (2) mounted on a platform (not shown) as per the requirement, size and type of chassis component (4). All these gauges (2) are mounted on the one base plate of platform as per tool design coordinates and two master units are there at the base plate which locates the vehicle chassis (4). The gauge (2) comprises of bottom L block (5), spacer block (6) and cover plate (7). The spacer block (6) with cover plate (7) on top suitably mounted on L block (5).The said cover plate provided with circular opening. Spacer block (6) has two sliding blocks built therein with a slide which moves in X and Y directions. The slide block A (10) slides in X direction whereas slide block B (11) slide in Y direction. The Slide block A (10) is attached to slider A (14) whereas slide block B (11) is attached to slider B (15). Referring to figure 4, the combination of slides fixed to the slide block A and slide block B forms cross slider. A bush (13) is mounted on the said slide block A (10), facing cover plate, through the cover plate circular opening. The slide blocks are attached to the potentiometer unit (8) incorporated therein against the lock nut (9) by suitable means. Potentiometer unit (8) comprises of spring loaded plunger (16) for self equalising and potentiometer to sense the linear movement of plunger and generates electrical signal in the form of voltage difference proportionate to
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the pressure on said spring loaded plunger. The said bush (13), mounted on slide block A (10) protruding out through the circular opening on cover plate, aligned with the check point of chassis under checking by means of a pin (12) to be inserted manually to center the chassis (4).
In order to check the significant characteristics (SC) and critical characteristics (CC) parameters, the chassis (4) is mounted on the multi-gauging system (1) and is clamped to it. A metal pin (12) is passed into a bush (13) through check point of a chassis component being checked. The bush (13) is mounted on the cross slides. Insertion of metal pin (12) centers the component of the chassis (4) on the gauge (2). In the process the slide blocks 10 and 11 slide linearly in X and Y directions along with sliders 14 and 15 respectively if the alignment of check point is not correct. While positioning the bush (13) there is movement of cross slide in X and Y direction which is sensed by the potentiometer which then transfer the displacement of spring loaded plunger in the form of voltage differences to CPU through PLC and actual dimension is fed to the data analyser.
The linear movement of the slide blocks compresses the spring (16) in potentiometer unit (8). Referring to Figure 5, the compression of the spring is sensed by the plurality of potentiometers, such as Gl, G2, G3, and like, in the form of voltage difference. This analogue electrical input is then fed as an input to the data decoder. The data decoder is configured to interpret the voltage difference into digital form. The output of data decoder is given as an input to the data analyser. The data analyser is configured to analyze the data and check it with the set standards and process it to the output
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terminal. Output terminal may be display screen (single or plural) and/or storage device. The analyzed dimensional report can be stored for further reference in the data storage device which can be retrieved as and when required.
The set values and tolerances of different parameters are fed to the system on the basis of which the system gives the result whether the particular component of the chassis is qualified or not as shown below.
Dimensional Report—

The foregoing objects of the invention are accomplished and the problems and shortcomings associated with prior art techniques and
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approaches are overcome by the present invention described in the present embodiment.
Detailed descriptions of the preferred embodiment are provided herein; however, it is to be understood that the present invention may be embodied in various forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but rather as a basis for the claims and as a representative basis for teaching one skilled in the art to employ the present invention in virtually any appropriately detailed system, structure or matter. The embodiments of the invention as described above and the methods disclosed herein will suggest further modification and alterations to those skilled in the art. Such further modifications and alterations may be made without departing from the spirit and scope of the invention; which is defined by the scope of the following claims.
Advantages of the Present Invention:
1. The online system permits checking of a chassis frame assembly within three minutes for required parameters, which otherwise would have taken an entire day for a single chassis on a CMM/ optical LEICA. Also, Trend Charts (X-bar & R- Charts) are available immediately and process variations if any, can be detected well in time.
2. The system in mention is used to check 16 different SC/CC parameters on a single chassis frame assembly within tact of 3 minutes.
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We claim:
1. A multi-gauging system for vehicle chassis for checking the dimensions comprises a platform for mounting the chassis (4) to be inspected; the said platform is having a pair of master units to locate the said chassis (4) on the said platform base plate as per the tool design coordinates; plurality of gauges (2) are mounted on the said base plate at various locations for inspecting check points of chassis (4) to be inspected; the said gauge (2) is having a bush (13), mounted on the sliding block fixed to the cross slide which moves in x-axis and /or y-axis when an individual pin (12) is inserted through the said check points, if the said check point is not exact location on chassis; a pair of potentiometer (8) is fixed to said gauges (2) which is having spring biased plunger self equalising and said plunger is resting against the individual sliding blocks; the said potentiometer (8) is electrically connected to as an input to the data decoder and the output of the said data decoder is inputted to the data analyser which is configured to analyze the data and check it with the set standards and process it to the output terminal.
2. A multi-gauging system for vehicle chassis as claimed in claim 1 wherein the said gauge (2) comprises a bottom L- block (5), top cover plate with circular opening and middle a spacer having pair of built in sliding blocks (10/11) movable in X & Y directions respectively ,one facing cover plate (7) and other facing L-bracket, mounted on the individual slide forming cross slides (14,15); a bush
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(13) is mounted on the said sliding block facing cover plate through the said circular opening.
3. A multi-gauging system for vehicle chassis as claimed in claims 1&2 wherein the said potentiometer unit (8) comprises of spring loaded plunger for self equalising and potentiometer to sense the linear movement of plunger attached to the said sliding blocks (10,11) of the gauge (2) and generates electrical signal in the form of voltage difference proportionate to the pressure on said spring loaded plunger.
4. A multi-gauging system for vehicle chassis as claimed in claim 1 where in the said output terminal may be display screen (single or plural) and/or storage device.
5. A multi-gauging system for vehicle chassis as claimed in claim 1
wherein PLC of the system is embedded with custom built software
/ logic which interpret the voltage difference sensed by the
potentiometer (8) into digital display; the tolerances of different
parameters are fed to the system to get the result displayed
whether the particular component of the chassis is qualified or not.

Date 14th August 2008.

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