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 OF THE INVENTION
A gauge for testing an end shield of an alternator housing.
APPLICANTS
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR
Kulkarni Raghvendra Krishnaji of Crompton Greaves Ltd, Alternator and DC Machines, LT Motor Division, A-6/2 MIDC, Ahmednagar 414111, Maharashtra, India; an Indian National.
PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the nature of this invention and the manner in which it is to be performed:

Field of the Invention:
This invention relates to the field of the mechanical devices.
Particularly, this invention relates to the field of mechanical devices for
testing.
Still particularly, this invention relates to a gauge for testing an end shield (housing) of an alternator.
Background of the Invention:
An alternator is an electromechanical device that converts mechanical energy to electrical energy in the form of alternating current. Most alternators use a rotating magnetic field but linear alternators are occasionally used. In principle, any AC electrical generator can be called an alternator, but usually the word refers to small rotating machines driven by automotive and other internal combustion engines.
An alternator is shipped along with its housing from a manufacturer to a consumer. This housing includes an end shield with two operative sides. One operative side interfaces with the alternator, while the second operative side is used by the consumer.
Typically, an alternator housing comprises an end shield with a substantially circular ring with a set of holes drilled through its circumference, i.e. on said ring. Typically, these holes are through-holes. The holes are located at pre-

defined equi-chord-distance along the circumference. These holes are further used for aligning said alternator housing with engine housing holes, with end user / consumer equipment. Hence, there is a need that these holes be located exactly as per specification, without aberrations.
The ideal parameters for a 'good' end shield of an alternator are:
1) specified pitch circle diameter of ring;
2) specified hole straightness / taper ness of ring;
3) specified number of holes on said ring;
4) specified hole size on said ring;
5) specified chord distance between two adjacent holes.
There is a need to verify that the specified parameters are in accordance with user requirement as well as to ensure that the ring is machined and drilled in accordance with specified manufacturing standards for improving quality and increasing repeatability.
It has been observed that the machine which performs the tasks of machining said ring and drilling said holes in said drill is subject to misalignment due to repetitive actions of tasks. E.g. the drill may wear out causing no holes to be drilled or holes of aberrant dimensions are drilled. The location of holes may be improper. The drilling frequency of the machine may be disturbed.
Hence, there is a need to arrest these above-mentioned causes of concern and provide a testing instrument, particularly, a gauge to test the machined rings

at pre-defined intervals to understand whether the machine which machines and drills said ring is performing according to specified standards or not.
Prior Art:
In the present system of operation, after machining is over, the end shield (ring) is placed on a jig and holes are drilled. The holes in the ring are then checked manually. Approximate time required for checking each hole is 20 Seconds. Further, the chord distance and Pitch circle diameter is measured by vernier caliper. This task takes approximately 3 minutes per job.
Alternators may be rejected on account of fitment problems. After analyzing the faulty adaptors, following points were noted:
1) Chord distance was not uniform.
2) Hole diameter found undersize.
3) Hole diameter found tapering.
There is need to overcome the above issues in a single stroke.
The US Patent US 5729906 ('906 patent) claims "An automated hole inspection system for measuring, on a plurality of planes, the diameter of hole in a work piece" (Claim 1), which measures the hole diameter in one plane, and inspecting the diameter of a hole in a plurality of planes.
The Japanese publication JP 2004317271, discloses a gauge, which measures PCD (Pitch Circle Diameter) of a bolthole.

The Japanese patent JP 228640, disclosed a wheel cap for a wheel which is provided with bolt holes with two or more pitch circle diameters with provision of plural fixtures.
However, the listed prior arts do not disclose the concept of checking plurality of pins and for measuring chord distance, PCD, hole diameter, and hole straightness with a single gauge.
Objects of the Invention:
An object of the invention is to efficiently and quickly check the machined end shield of an alternator housing.
Another object of the invention is to efficiently and quickly check the holes drilled in the end shield of the alternator.
Yet another object of the invention is to save time in relation to checking the end shield of the alternator.
Still another object of the invention is to simultaneously check multiple parameters of the end shield of the alternator.
Summary of the Invention:
According to this invention, there is provided a gauge for testing an end shield of an alternator, said gauge comprises a ring fitted with a pre-defined number of pins protruding from a single operative side of said ring, said pins

adapted to be in accordance with pre-defined dimensions and each of said pin located with respect to said adjacent pin with a pre-defined intermediate chord distance.
Preferably, said gauge includes a first set of diametrically opposite located operative vertical plates on internal circumference of said ring.
Preferably, said gauge includes a second set of diametrically opposite located operative vertical plates on external circumference of said ring.
Brief Description of the Accompanying Drawings:
The invention will now be described in relation to the accompanying drawings, in which:
Figure 1 illustrates a schematic of the gauge for testing the end fixture of an alternator housing;
Figure 2 illustrates a schematic of the gauge for testing;
Figure 3 illustrates a schematic of the end shield of the alternator; And
Figure 4 illustrates another schematic of the gauge for testing.

Detailed Description of the Accompanying Drawings:
According to this invention, there is provided a gauge (100) for testing end shield (200) of an alternator housing.
Figure 1 illustrates a schematic of the gauge for testing the end shield of an alternator. Figure 2 illustrates a schematic of the gauge for testing. Figure 3 illustrates a schematic of the end shield of the alternator. Figure 4 illustrates another schematic of the gauge for testing.
In accordance with an embodiment of this invention, there is provided a ring (10) with a pre-determined diameter, said diameter being equal to the diameter of the end shield of said alternator. This ensures that the gauge may be co-axially located with the end shield for purposes of testing. Any aberrations in the end fixture will not allow the ring (and hence, the gauge) to be fitted co-axially.
In accordance with another embodiment of this invention, there is provided a plurality of pins (20) protruding out of a single operative side of said ring. These pins are in correlation to the number of holes (25) to be checked on said end shield of said alternator. The pins complement with the holes, thus determining their presence when said gauge engages with said end shield. If the pins penetrate each of said holes, it indicates that holes are present on the end shield, as desired. Further, the studs are located at pre-determined chord distance with respect to each pair of adjacent pins. This chord distance determines that the holes also maintain the same pre-defined chord distance. Typically, the pins are of a pre-defined diameter and height. These pre-

defined dimensions ensure that the hole which receives said pins fully neither taper, nor having varying dimensions.
In accordance with yet another embodiment of this invention, there is provided a first set of diametrically opposite located operative vertical plates (30) on internal circumference of said ring. When the gauge engages with the end shield, the first set of plates should touch the internal diameter of the end shield, thus determining that the end shield internal diameter is in accordance with specified parameters.
In accordance with still another embodiment of this invention, there is provided a second set of diametrically opposite located operative vertical plates (40) on external circumference of said ring. When the gauge engages with the end shield, the second set of plates should touch the external diameter of the end shield, thus determining that the end shield external diameter is in accordance with specified parameters.
Due to the gauge of this invention, the checking time reduces to typically 40 seconds per alternator housing, and all the requisite parameters are simultaneously checked.

We claim,
1. A gauge for testing an end shield of an alternator, said gauge comprising a ring fitted with a pre-defined number of pins protruding from a single operative side of said ring, said pins adapted to be in accordance with pre-defined dimensions and each of said pin located with respect to said adjacent pin with a pre-defined intermediate chord distance.
2. A gauge as claimed in claim 1 wherein, said gauge includes a first set of diametrically opposite located operative vertical plates on internal circumference of said ring.
3. A gauge as claimed in claim 1 wherein, said gauge includes a second set of diametrically opposite located operative vertical plates on external circumference of said ring.