FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
As amended by the Patents (Amendment) Act, 2005
AND
The Patents Rules, 2003
As amended by the Patents (Amendment) Rules, 2005
COMPLETE SPECIFICATION (See section 10 and rule 13)
TITLE OF THE INVENTION
An adjustable mandrel for holding a wound pack
APPLICANTS :
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030, Maharashtra, India, an Indian Company
INVENTOR (S):
Bhujbal Eknath Ramdas and Shete Sachin Dattatraya., both of Crompton Greaves Ltd, Motors Division (M3), A-6/2 MIDC Ahmednagar 414111, Maharastra, India; both Indian Nationals.
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 mechanical assemblies, devices, and equipment.
Particularly, this invention relates to an adjustable mandrel for holding a wound pack under a trickle impregnation machine.
Background of the Invention:
Winding in the electric motor plays an important role in the performance of the motor. It is essential for better functioning of motor to have windings properly wound and baked in an oven.
Certain motors have the windings protected by epoxy resin or varnish. By impregnating the transformer with epoxy under a vacuum, one can replace air spaces within the windings with epoxy, thus sealing the windings and helping to prevent the possible formation of corona and absorption of dirt or water. This produces transformers more suited to damp or dirty environments.
The entire winding along with its shell is dipped in a tank containing the varnish. The varnish, therefore, coats the winding, and also coats the shell from outside. Another method is trickle impregnation, wherein a trickle machine allows varnish to trickle onto a wound pack (of the motor) that is held below the trickling point. It is important that the wound pack is held appropriately under the trickle stream of varnish and is able to rotate in order to fully cover the wound pack with varnish.

Prior Art:
US5685910 discloses an apparatus for coating an electromagnetic coil. However, this is an external clamping mechanism which does not suit trickle impregnation system.
GB1157952 discloses a Trickle Impregnation Machine. However, adjustable mechanism for receiving a plurality of wound pack sizes is not disclosed.
Objects of the Invention:
An object of the invention is to provide a modular mandrel for incorporating a holding'mechanism for wound packs of various sizes.
Another object of the invention is to provide a mandrel which reduces the time consuming process of wound pack loading and unloading during impregnation process.
Yet another object of the invention is to provide ease of cleaning of mandrel.
Still another object of the invention is to provide an easy-to-manufacture mandrel.
An additional object of the invention is to provide a less costly mandrel.
Yet an additional object of the invention is to provide a mandrel which reduces the cycle time of loading and unloading the wound pack onto / from it.

Summary of the Invention:
According to this invention, there is provided an adjustable mandrel for holding a wound pack, said mandrel comprises:
a. circular base plate with a central shaft extending orthogonally from the
centre of said base plate;
b. plurality of jaws placed about the central shaft, said jaws being substantially
parallel to said central shaft, and adapted to move away from said central
shaft in its expanded configuration, and further adapted to move towards
said central shaft in its collapsed condition, said jaws further adapted to rest
against the inner wall of wound pack with a central hollow portion inserted
about the central shaft in a circumferential manner and hold the wound pack
due to force exerted in its inner wall;
c. first links extending orthogonally from said central shaft, said links being
radially dispersed about said central shaft at an operative lower portion of
said central shaft, each of said first links corresponding to each of said jaws
that are radially dispersed about said central shaft;
d. second links extending orthogonally from said shaft, said links being radially
dispersed about said central shaft at an operative upper portion of said
central shaft, each of said second links corresponding to each of said jaws
that are radially dispersed about said central shaft;
e. coaxial shaft adapted to said central shaft;
f. screw adapted to determine motion of said coaxial shaft in and out of said
central shall; and
g. third links adapted to connect said coaxial shaft to said second links
correspondingly;

wherein, said screw moves said co-axial shaft into said central shaft, thereby moving said third links to actuate said second links and first links subsequently into an operative expanded position of said jaws and wherein, said screw moves said co-axial shaft out of said central shaft, thereby moving said third links to actuate said second links and first links subsequently into an operative collapsed position of said jaws.
Typically, said link is a substantially elongate plate.
Typically, said central shaft includes first collar piece extending from said central shaft, said collar adapted to connect a first end of said first link to said central shaft.
Typically, said central shaft includes second collar piece extending from said central shaft, said collar adapted to connect a first end of said second link to said central shaft.
Typically, said mandrel includes a first hinge pin adapted to connect said first link to said central shaft.
Typically, said mandrel includes a second hinge pin adapted to connect said first link to said jaw.
Typically, said mandrel includes a third hinge pin adapted to connect said second link to said central shaft.

Typically, said mandrel includes a fourth hinge pin adapted to connect said second link to said jaw.
Typically, .said mandrel includes a fifth hinge pin adapted to connect said third link to said co-axial shaft.
Typically, said mandrel includes a sixth hinge pin adapted to connect said third link to said second link.
Brief Description of the Accompanying Drawings:
Figure la illustrates a front sectional view of the mandrel of the prior art; and
Figure lb Illustrates a (op sectional view of the mandrel of the prior art.
The invention will now be described in relation to the accompanying drawings, in which:
Figure 2a illustrates a front sectional view of the mandrel in its expanded condition;
Figure 2b illustrates a top sectional view of the mandrel in its expanded condition;
Figure 3a illustrates a front sectional view of the mandrel in its collapsed condition; and
Figure 3b illustrates a top sectional view of the mandrel in its collapsed condition.

Detailed Description of the Accompanying Drawings:
Figure la illustrates a front sectional view of the mandrel of the prior art; and Figure 1 b illustrates a top sectional view of the mandrel of the prior art.
There is a fixture / mandrel ('10) for mounting a wound pack (12) during impregnation process on a trickle: machine. This fixture / mandrel (10) facilitates holding, rotation of wound pack (12) having coil over hang, indexing and protecting at the same time. This fixture is used for electrical winding of induction motor/ rotating machine. It includes a base of circular plate (14) and jaws (16).
A central shaft (18) is provided \. hich remains concentric with the received wound pack and provides a base for operation of the jaws (16). Hinge plates (11) from the shaft (18) extend such that they operate the jaws (16) from an operative collapsed position of the jaws (16) to an operative expanded position of the jaws (16). The shaft (1 8) includes a threaded stud (13) which when rotated operates the shaft in an axial forward direction or in an axial reverse direction depending upon the threading movement in order in operate the hinge plates (11) and jaws (16), thereby.
The jaws (16) and hinge plate (11) are of a specific length and size for a specific wound pack. If the wound pack size changes, the same jaws and hinge plate cannot be used for the changed wound pack. For a larger wound pack, a larger set of jaws and hinge plates arc required, thus increasing the weight of the mandrel. The hinge plates (11), as connected to the jaws (16) provide a limited range of movement

from expansion to collision of the jaws (16) and from collision to expansion of the jaws (16).
Hence, a specific mandrel is required for a particular wound pack. While using this type of mandrel, varnish goes inside of mandrel and it is difficult to clean the mandrel. Since this is a non-modular mandrel, for a different wound pack, a different mandrel needs to be installed onto the holding machine which holds the mandrel and the wound pack under the trickle machine. In the prior art, therefore, right hand threads for moving axially in order to move the hinge plates for expansion and collision positions. The weight of the mandrel is relatively more and the design of the mandrel is relatively complicated.
According to this invention, there is provided an adjustable mandrel for holding a
wound pack undera trickle impregnation machine.
Figure 2a illustrates a front sectional view of the mandrel in its expanded condition;
Figure 2b illustrates a top sectional view of the mandrel in its expanded condition;
Figure 3a illustrates a front sectional view of the mandrel in its collapsed
condition: and
Figure 3b illustrates a top sectional view of the mandrel in its collapsed condition.
In accordance with an embodiment of this invention, there is provided a circular base plate (21) with a central shaft (22) extending orthogonally from the centre of said base plate (21).
In accordance with another emnodiment of this invention, there is provided a plurality of jaws (23) placed a) out the central shaft (22), said jaws (23) being

substantially parallel to said shall (22). In its expanded configuration, the jaws (23) move away from said shaft (22) and in its collapsed condition, the jaws (23) move towards the shaft (22). A wound pack (12) which has a central hollow portion is inserted about the shaft (22) and jaws (23) while the jaws are in their collapsed condition. As the jaws (23) move towards the shaft (22), the collapsed condition is achieved and any wound pack may be received by the mandrel about the shaft (22) and the jaws (23). As the jaws (23) move away from the shaft (22), the expanded condition is achieved. The jaws (23) touch the inner diameter wall of the wound pack and rest against it in a circumferential manner due to the plurality of jaws (23) located radially about the shall (22).
In accordance with yet another embodiment of this invention, there is provided a first links (24, 25) extending orthogonally from said shaft (22), said links being radially dispersed about the shaft (22) at an operative lower portion of said shaft. Each link (24, 25) at the lower portion of the shaft (22) corresponds to each jaw (23) that is radially dispersed about the shaft (22). Each link (24, 25) is a substantially elongate plate. One end (24a) of each link (24, 25) of the lower portion of the shall (22) is connected by a hinge pin to the shaft (22) such that the link may move about the shall. The other end (24b) of each link (24, 25) of the lower portion of the shaft (22) is connected by another hinge pin to the jaw such that as the shaft (22) moves, the link (24, 25) moves and the hinge pin causes the links (24, 25) to expand or collapse the jaws (23).
Preferably, the links (24, 25) extend from the collars (26) extending from said shaft (22).

In accordance with still another embodiment of this invention, there is provided a second links (27, 28) extending orthogonally from said shaft, said links being radially dispersed about the shall (22) at an operative upper portion of said shaft (22). Each link (27, 28) at the upper portion of the shaft (22) corresponds to each jaw (23) that is radially dispersed about the shaft (22). Each link (27, 28) is a substantially elongate plate. One end (27a) of each link (27, 28) of the lower portion of the shaft (22) is connected by a hinge pin to the shaft (22) such that the link may move abotit the shaft. The other end (27b) of each link (27, 28) of the lower portion of the shaft (22) is connected by another hinge pin to the jaw such that as the shall (22) moves, the link (27, 28) moves and the hinge pin causes the links (27, 28) to expand or collapse the jaws (23).
Preferably, the links (27, 28) extend from the collars (29) extending from said shaft (22).
In accordance with an additional embodiment of this invention, there is provided a coaxial shaft (31) to said central shaft (22). There is a screw (32) adapted to allow motion of said coaxial shaft (31) wiLhin and out of said central shaft (22)
In accordance with yet an additional embodiment of this invention, there is provided a third links (33, 34) adapted to connect said coaxial shaft (31) to said second links (27, 28) correspondingly. Each link (33, 34) is a substantially elongate plate. One end (33a) of each link (33, 34) of the coaxial shaft (31) is connected by a hinge pin to the coaxial shaft (3 I) such that the link may move about the coaxial shaft. The other end (33b) of each link (33, 34) of the coaxial shaft (31) is connected by another hinge pin to the jaw such that as the coaxial shaft (31)

moves, the link (33. 34) moves and the hinge pin causes the links (27, 28) to expand or collapse the jaws (23). The other end (33b) of these links are located substantially at the/centre of the second links (27, 28) in order to propel their
movement in operative axial directions.
As the jaws move towards the inner wall of the wound pack, and exert pressure, the wound pack locks over the mandrel. The inner diameter of the wound pack does not matter as the jaws are operable from their totally collapsed state to their totally expanded state providing a range of motion, in between to accommodate various wound packs with various sizes and inner diameters, thereof.
Cleaning of this mandrel is easy, due to its construction. It is also relatively easy to manufacture this mandrel as compared to prior art mandrels. It is relatively less expensive (i.e. Single mandrel for various wound packs having different bores instead of separate mandrels.) Cycle time of loading different mandrels of different sizes is eliminated as one mandrel takes care of a plurality of sizes of wound packs.
While this detailed description has disclosed certain specific embodiments of the present invention for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

We claim,
1. An adjustable mandrel for holding a wound pack, said mandrel comprising:
a. circular base plate with a central shaft extending orthogonally from the
centre of said base plate;
b. plurality of jaws placed about the central shaft, said jaws being substantially
parallel to said central shall, and adapted to move away from said central
shall in its expanded configuration, and further adapted to move towards
said central shaft in its collapsed condition, said jaws further adapted to rest
against the inner wall of wound pack with a central hollow portion inserted
about the central shaft in a circumferential manner and hold the wound pack
due to force exerted in it's inner wall;
c. first links extending orthogonally from said central shaft, said links being
radially dispersed about said central shaft at an operative lower portion of
said central shaft, each of said first links corresponding to each of said jaws
that arc radially dispersed about said central shaft;
d. second (inks extending orthogonally from said shaft, said links being radially
dispersed about said centra! shaft at an operative upper portion of said
central shaft, each of said second links corresponding to each of said jaws
that arc radially dispersed about said central shaft;
e. coaxial shaft adapted to said central shaft;
f. screw adapted to determine motion of said coaxial shaft in and out of said
central shaft; and
g. third links adapted to connect said coaxial shaft to said second links
correspondingly;
wherein, said screw moves said co-axial shaft into said central shaft, thereby moving said third links to actuate said second links and first links subsequently

into an operative expanded position of said jaws and wherein, said screw moves said co-axial shaft out of said central shaft, thereby moving said third links to actuate said second links and first links subsequently into an operative collapsed position of said jaws.
2. A mandrel as claimed in claim 1 wherein, said link is a substantially elongate plate.
3. A mandrel as claimed in claim 1 wherein, said central shaft includes first collar piece extending from said central shaft, said collar adapted to connect a first end of said first link to said central shaft.
4. A mandrel as claimed in claim } wherein, said central shaft includes second collar piece extending from said central shaft, said collar adapted to connect a first end of said second i ink to said central shaft.
5. A mandrel as claimed in claim 1 wherein, said mandrel includes a first hinge pin adapted to connect said first link to said central shaft.
6. A mandrel as claimed in claim 1 wherein, said mandrel includes a second hinge
pin adapted to connect said first link to said jaw.
7. A mandrel as claimed in claim 1 wherein, said mandrel includes a third hinge pin adapted to connect said second link to said central shaft.
8. A mandrel as claimed in claim 1 wherein, said mandrel includes a fourth hinge pin adapted to connect said second link to said jaw.

9. A mandrel as claimed in claim I wherein, said mandrel includes a fifth hinge pin adapted to connect said third link to said co-axial shaft.
10.A mandrel as claimed in claim 1 wherein, said mandrel includes a sixth hinge pin adapted to connect said third link to said second link.