FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
A system for calibration of knee bending potentiometer of a pedestrian legform
and the method of calibration 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
Kedar Panmand and Rajesh Chaugule 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 specification particularly describes the invention
and the manner in which it is to be performed.


FIELD OF INVENTION
This invention relates to calibration of a rotary knee bending potentiometer and more particularly it relates to a system for calibration of knee bending potentiometer of a pedestrian legform.
BACKGROUND OF INVENTION
Legform impactor is used for assessment of the injury potential of vehicle front end in the event of a moving vehicle impacting a pedestrian. The legform impactor consists of two cylindrical members representing tibia (10) and femur. The tibia (10) and femur are joined by a metallic strip called as knee bending ligament. During testing the inertial forces of tibia and femur makes the knee bending ligament to bend. The femur has been provided with a rotary potentiometer to measure the relative bend between the tibia and femur.
In line with conventional practice of periodic calibration of the measuring instruments, the subject rotary potentiometer also requires a periodic calibration. During the periodic calibration the subject rotary potentiometer is removed from the femur and calibrated as per the standard procedure for potentiometer calibration. The subject rotary potentiometer assembly to the femur is time consuming due to its location, cable routing and assembly arrangement. Therefore there is a need to have a facility by which the rotary potentiometer can be calibrated in as installed condition.
OBJECTS OF THE INVENTION
The main objective of the present invention is to provide a portable kit for calibration of knee bending potentiometer of a pedestrian legform.
Yet another object of the present invention is to provide a portable kit for calibration of knee bending potentiometer of a pedestrian legform wherein said potentiometer is calibrated in as installed condition.
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STATEMENT OF THE INVENTION
A system for calibration of knee bending potentiometer of a pedestrian legform
comprises
follower member connected to said knee bending rotary potentiometer disposed in
femur,
electric circuitary interfaced with said knee bending rotary potentiometer ;
calibration template mounted at the knee bending ligament position in femur;
an extension member configured to attach to the follower member connected with
knee bending rotary potentiometer disposed in femur;
and pin member configured to connect the end of the said extension member and said
template.
BRIEF DESCRIPTION OF THE INVENTION
A system for calibration of knee bending potentiometer of a pedestrian legform comprises; calibration template (4) mounted at the knee bending ligament position in the femur, said template (4) comprises plurality of holes (5) at circumference of pitch circle (6) centered at the centre of the knee bending rotary potentiometer (2) in the femur member (1), an extension member (7) attached to the follower member (3), pin member (8) configured to connect the end of the said extension member and said template (4) with the help of holes (5) provided on the said template, and method of calibration of knee bending rotary potentiometer thereof.
BRIEF DESCRIPTION OF DRAWINGS
Figure-01 shows general construction & functioning of a pedestrian legform impactor. Figure-02 shows top view with details of the constructional features of the knee bending rotary potentiometer arrangement,
Figure-03 shows top & side sectional view of the femur when assembled with calibration kit for the knee bending rotary potentiometer.
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Figure-04 shows a portable kit for calibration of the knee bending potentiometer of a pedestrian legform in accordance with this invention.
DETAILED DESCRIPTION OF THE 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 02-04, A portable kit for calibration of knee bending potentiometer of a pedestrian legform comprises; calibration template (4) mounted at the knee bending ligament position in the femur (1), said template (4) comprises plurality of holes (5) at circumference at pitch circle (6) centered at the centre of the knee bending rotary potentiometer (2) disposed in the femur member (1), an extension member (7) attached to the follower member (3), pin member (8) configured to connect the end of the said extension member and said template (4) with the help of holes (5) provided on the said template.
The said potentiometer follower (3) is engaged /connected with the said rotary potentiometer (2) at one end and with extension member (7) at other end. During calibration of the knee bending potentiometer, the legform is dismantled. The bending ligament (9) is replaced by the calibration template (4). Said follower (3) is attached to the knee bending rotary potentiometer (2). The said follower (3) is positioned against the said calibration template (4) with the help of the said pin member (8) which connects the said extension member (7) and the said calibration template (4). The knee bending rotary potentiometer (2) is connected to the requisite electrical circuitary. The said potentiometer (2) is moved through a predetermined angle by rotating the said follower (3) against the holes (5) provided on the said calibration template (4) through the said pin member (8). Due to the rotation of the said potentiometer (2), there is a change in its electrical resistance which is measured by the electrical circuitary. Thus a relation is established between the change in the
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electrical resistance to the rotation of the potentiometer (2) and the potentiometer is
calibrated.
The no of holes provided and extent of the sector on the said calibration template is
variable depending on the accuracy and range of calibration required.
In accordance with another embodiment of the invention, A system for calibration of knee bending potentiometer of a pedestrian legform comprises; a knee bending potentiometer calibration template (4) mounted at the knee bending ligament position in the femur (1), said template (4) comprises a slot (not shown) at circumference of pitch circle (6) centered at the centre of the said knee bending rotary potentiometer (2) disposed in femur, an extension member (7) attached to the follower member (3), a pin member (8) configured to connect the end of the said extension member and said template (4) with the help of holes (5) provided on the said template. Mounting arrangement is same as described in first embodiment of the invention. For calibration, The said potentiometer (2) is moved through a predetermined angle by rotating the said follower (3) in the said slot (not shown) provided on the said calibration template (4) through the said pin member (8). Due to the rotation of the said potentiometer (2), there is a change in its electrical resistance which is measured by the electrical circuitary. Thus a relation is established between the change in the electrical resistance to the rotation of the potentiometer (2) and the potentiometer is calibrated.
In accordance with the present invention, method of calibration comprising;
• Dismantling the Legform to separate the tibia, femur & the bending ligament,
• Inserting and fastening said calibration template in femur at the place of the bending ligament,
• Attaching the said Extension member to the follower of the knee bending potentiometer,
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• Inserting said Pin member through the extension member & engaging with a hole on the calibration template,
• Connecting knee bending potentiometer to the electrical circuitary to measure the electrical response,
• Rotating knee bending potentiometer follower alongwith the extension member by said pin member such that pin member can be engaged in the any appropriate hole on the calibration template,
• Recording the change in the electrical response due to the rotation of the potentiometer,
• Repeating the above process till adequate range of rotation of the potentiometer is covered,
• The extent of rotation is predetermined based on the hole configuration on the calibration template,
• Establishing the relation between electrical response change with the associated rotation of said follower to complete the calibration.
Thus with the present invention, the knee bending rotary potentiometer can be calibrated in as installed condition which reduces the calibration time significantly. It is also quite simple for reconfirmation of the calibration in case of any uncertainties. It's simple in construction and cost effective.
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.
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We Claim
1. A system for calibration of knee bending potentiometer of a pedestrian legform
comprises
Follower member connected to said knee bending rotary potentiometer disposed in femur,
electric circuitary interfaced with said knee bending rotary potentiometer ;
calibration template mounted at the knee bending ligament position in femur;
an extension member configured to attach to the follower member connected with knee bending rotary potentiometer disposed in femur;
and pin member configured to connect the end of the said extension member and said template.
2. The system as claimed in claim 1 wherein said template comprises of plurality of holes at circumference of pitch circle, centered at the centre of said knee bending rotary potentiometer in femur.
3. The system as claimed in claim 1 wherein said template comprises of a slot at circumference of pitch circle, centered at the centre of said knee bending rotary potentiometer.
4. The system, as claimed in claim 1 wherein pin member connects the end of the said extension member and said template with the help of said holes / slot provided on the said template.
5. The system as claimed in claim 1 wherein said follower member is engaged with said rotary potentiometer disposed in the femur at one end and with said extension meter at other end.
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6. The system as claimed in claim 1 wherein said calibration template is mounted at bending ligament position in femur after said legform is dismantled.
7. The system as claimed in claim 1 wherein said knee bending rotary potentiometer is interfaced with to said electric circuitary to measure change in resistance in said knee bending rotary potentiometer due to movement of said follower member.
8. Method of calibration of the knee bending potentiometer of a pedestrian legform comprising the steps of
dismantling the legform to separate the tibia, femur & the bending ligament;
inserting and fastening said calibration template in femur at the place of the bending ligament;
attaching the said extension member to the follower of the knee bending potentiometer;
inserting said pin member through the extension member & engaging with a hole on the calibration template;
connecting knee bending potentiometer to the electrical circuitary to measure the electrical response;
rotating knee bending potentiometer follower alongwith the extension member by said pin member such that pin member can be engaged in any appropriate hole on the calibration template;
recording the change in the electrical response due to the rotation of the potentiometer;
repeating the above process till adequate range of rotation of the potentiometer is covered;
extent of rotation is predetermined based on the hole / slot configuration on the calibration template;
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and establishing the relation between electrical response change with the associated rotation of said follower to complete the calibration.
The system for calibration of knee bending potentiometer of a pedestrian legform substantially as herein described in the description as illustrated with reference to the accompanying drawings.
Method of calibration of the knee bending potentiometer of a pedestrian legform substantially as herein described in the description as illustrated with reference to the accompanying drawings.
Dated this 17th day of July 2009

Karuna Goleria of DePENNING & DePENNING

TATA MOTORS LIMITED By their Agent & Attorney