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, 2006
COMPLETE SPECIFICATION
(Sec section 10 and rule 13)
TITLE OF THE INVENTION A notching press tool
APPLICANT
Crompton Greaves Limited, CG House, Dr Annie Besant Road, Worli, Mumbai 400 030,
Maharashtra. India- an Indian Company
INVENTOR
Chandrashekhaf Ramakant Keluskar of Stamping Division. Crompton Greaves Ltd, Kanjur
Marg, Mumbai 400042, Maharashtra, India, an Indian National
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
[1001] The present invention relates generally to notching presses and more
particularly, to notch press tools for punching out rotor and stator laminations from sheet materials.
DESCRIPTION OF THE BACKGROUND ART
[002] Notching press tool used within notching presses are commonly known and
are highly useful for producing various types of notches in sheet-like work pieces of metal. plastic, composite materials and the like in one stroke of the punching section against the die bed. Generally, the punch has a protruding cutting profile extending therefrom and the die has a similar passage therein to conform the punch. A sheet material is positioned on the die bed and the punching section, which reciprocates along a punching axis, strikes the sheet with an impact resulting in creation of a notch on the sheet material. Such notching presses find immense application in formation of laminations capable of being used within alternators. Such laminations are positioned at each end of the rotor and stator core laminations and tied together in known manner.
[003] During punching operation in notching presses, the dimension of the notches created
is very extremely critical. In order to avoid rejections, the dimensions of me notches created have to be within cutting clearances and tolerances widely adapted in industry. However, many a times it has been observed that the dimensions exceed the maximum and minimum limits due to variety of reasons such as vibrations during punching operation, mis fed, collapsing of portions of the sheet material adjacent to the cutting zones, punching tool size, etc.. to name a few. If there is a problem in the punching tool size then the punching tool needs to be replaced which may lead to huge cost disadvantage. However, the most problematic of all the above reasons mentioned above is collapsing of the sheet material during punching operation. This happens due to creation

of vacuum between the punching end and the sheet material. As a result of this vacuum, portions of the sheet materia! adjacent to the punching zone collapses within the slot resulting in the dimension of the slot exceeding the acceptable level. Thus, there is a need to find a solution especially to this problem to avoid lamination rejections.
SUMMARY OF THE INVENTION
|004| Accordingly disclosed herein is a notching press tool for punching out rotor
and stator laminations from a sheet material rotatably positioned within a notching press including a longitudinal punch member extending between a front cutting end and a rear end. the rear end being releasably insertable into a punch holder and front cutting end protruding outwardly from the punch holder, the front cutting end having a projection sufficiently formed thereon, and a die having a slug passage formed therethrough that conforms the longitudinal punch member, the die attached to a die bed and having the sheet member positioned thereon that is rotatable in stepped manner, the die bed and the punch holder capable of cooperating with each other along a punching axis to sequentially form a plurality of spaced apart notches on the rotatable sheet material, the projection occupying space between the front cutting end and a portion of the sheet material while forming a corresponding notch.
[005J According to some embodiments, the punch holder includes a stepped portion
formed thereon, the stepped portion having a central slot formed therein for releasably positioning the rear end of the longitudinal punch member.
[006| According to some embodiments, the die bed is formed in a stepped
configuration to match the stepped portion of the punch member during notch formation on the sheet material.
[007| According to some embodiments, the die bed includes a pair of guide rods
releasably attached thereto and the punch holder has a pair of guide holes formed therein, and

wherein the pair of guide rods is received within the corresponding guide holes lo provide a controlled relative movement between the punch holder and the punch plate during punching operation.
[008] It is to be understood that both the foregoing genera! description and the
following detailed description of the present embodiments of the invention are intended to provide an overview or framework for understanding the nature and character of the invention as it is claimed. The accompanying drawings are included to provide a further understanding of the invention and are incorporated into and constitute a part of this specification. The drawings illustrate various embodiments of the invention and together with the description serve to explain the principles and operation of the invention.
A BRIEF DESCRIPTION OF THE DRAWINGS
[009] The above-mentioned and other features and advantages of the various
embodiments of the invention, and the manner of attaining them, will become more apparent and will be better understood by reference to the accompanying drawings, wherein:
[0010] FIG. la is a perspective view of a punch member according to an embodiment
of the present invention;
[ 0011] FIG. lb is a side elevational view of the punch member of FIG. la:
[0012] FIG. 2 is a perspective view of a punch holder having the punch member of
FIG. la inserted therein according to an embodiment of the present invention:
[0O13] FIG. 3 is perspective view of a die shoe having a die bed fixedfy attached
thereto according to an embodiment of the present invention;
[0014] FIG. 4 shows a plurality of notches that are formed on a sheet material during
a punching operation; and

[0015] FIG. 5 shows a front elevational view of a lamination punched out from the
sheet material of FIG. 4 on completion of the punching operation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] FIG. la illustrates a longitudinal punch member !00 having a front end 102, a
rear end 104, and a body 106 extending between the front end 102 and the rear end 104. Preferably, the longitudinal punch member 100 is formed of a rectangular shape and all edges 108 thereof act as cutting surfaces during punching operation within a notching press (not shown). A pair of opposite sides of the longitudinal punch member 100 extending along the length of the punch member has a cutting rib 110 formed thereon. The cutting ribs ! 10 formed on each of the opposite sides extend between the front end 102 and the rear end 104 of the longitudinal punch member. The front end 102 of the longitudinal member acts as a primary cutting end for the longitudinal punch member 100 because the front end 102 provides the first cutting within a sheet material (not shown) during punching operation. Thus, the front end 102 and the pair of ribs 110 of the longitudinal punch member 100 create a required notch (not shown) within the sheet material. The shape of the notch created on the sheet material is similar to the front end 102 of the longitudinal punch member. It is to be understood that the longitudinal punching member may have other shapes, which are compatible with working of the invention, as well and are also considered to be within the scope of the present invention. Preferably, the longitudinal punch member 100 may be formed of steel or carbide that has long operational life.
[0017] As seen in FIG. la. the front end 102 of the longitudinal punch member 100
has a projection 112 formed thereon. Preferably, the projection I 12 is formed of a rectangular shape and positioned substantially in middle of the front end 102 in such a manner that most of the front end 102 surface is covered by the projection 112. Preferably, an elastomeric material may be used as the projection 1 12 that may be applied on the front end 102. In various other embodiments of the present invention, the projection 112 may also be inbuilt with the

longitudinal punch member. Alternatively, other means known in the art may also be used for formation of projection 112 on the front end 102 and considered to be within the scope of the present invention. FIG. lb shows the longitudinal punch member 100 and the projection I 12 from a side elevationaf view.
[0018] FIG. 2 shows a punch holder 114 according to an embodiment of the present
invention having the longitudinal punch member 100 attached therein. The punch holder I 14 is a rigid mechanical member and has a top surface 116. a bottom surface (not shown), and a thickness between the top surface 116 and the bottom surface. As seem in FIG. 2. a portion of the punch holder 114 has a height and is formed to have a stepped configuration 120. A top surface 122 of the stepped portion has a central slot (not shown) formed in the middle thereof to releasably hold the longitudinal punch member 100 therein. Dimensions of the central slot relative to the longitudinal punch member 100 are set in such a manner that the longitudinal punch member 100 can be inserted therein with a little applied pressure. For inserting ihe longitudinal punch member 100 within the central slot, the rear end 104 of the longitudinal punch member 100 is inserted in such a manner that front end 102 protrudes from the stepped portion 120 of the punch holder 114. Further, FIG. 2 also shows a pair of guide holes 124 provided within the punch holder 114. The pair of guide rods 140 is provided on the oppositely formed wing shaped portion 126 of the punch holder I 14. Each of the guide holes 124 receiving a corresponding guide rod (not shown) attached on a die bed 130 during punching operation.
|0019J FIG. 3 illustrates a perspective view of the die bed 130 according to an
embodiment of the present invention. The die bed 130 has a die 132 that is fixedly attached on a top surface 134 of the die bed 130. The die 132 is also formed of a stepped configuration 136 and has a slug passage 138 formed therethrough that allows the longitudinal punch member 100 to be received therein during punching operation for creating notches 146 on the sheet material (not shown). The stepped portions 120, 136 of both the punch member and the die bed 130 are

formed so as to lock with each other when the punching operation happens. The shape of the slug passage 138 conform the shape of the longitudinal punch member 100 so that when the longitudinal punch member 100 rams the sheet material rotatably positioned on the die bed 130, a profile similar to that of the longitudinal punch member 100 is created thereon. The die bed 130 preferably has a shape that conform the outer profile of the punch holder I 14. Preferably, the die bed 130 has at least two guide rods 140 protruding outwardly therefrom with each of the guide rods 140 have a bulging portion 142 on its free end. Preferably, each of the guide rods 140 is disposed on a corresponding wing shaped portion 144 of the die bed 130. similar to that of the punch holder 114. Each of the guide rods 140 is capable of being received within a corresponding guide hole of the punch holder 114. The guide rods 140 are movably connected within the circular guide holes 124 so as to allow controlled relative movement of the die bed 130 against the punch holder 114. In the above various embodiments of the present invention, the punch holder I 14 and the die bed 130 may be used within a notching press machine (not shown) that punches out rotor and stator laminations.
[0020] The punch holder i 14 is movable against the die bed 130 along a punching axis
so as to cooperate with each other for punching sheet material to create a plurality of notches 146. The notches 146 have a shape that conform the front end 102 of the longitudinal punch member. Before the punching operation starts, the sheet material, which preferably made from a metallic material and held within a feeding machine (not shown), is positioned over the die bed 130. As well known in the notching press machine art, the feeding machine that holds the sheet material operates on a mechanism that allows the sheet material to be held sheet material to periodically rotate therein. Preferably, the sheet material is rotatable within the feeding machine in a stepped manner. Thereafter, the sheet material is positioned on the die 132 with the peripheral portions of the sheet material positioned over the slug passage 138. Preferably, the sheet material has a marking and this marking serves as the starting point for making the notches

146 thereon. Once this is done, the notching press is turned on to start the punching operation with a predetermined frequency. Rotational Motion of the sheet material is synchronized with the frequency of the punch holder 114 displacement in such a way that once a punching stroke is completed the sheet material is rotatably displaced by a predetermined angle.
[0021] FIG. 4 shows a plurality of notches 146 corresponding to the shape of the
longitudinal punch member 100 being formed on a sheet material rotatably positioned on the die 132 during punching operation. As illustrated, the longitudinal punch member 100 strikes at one of the peripheral portions 150 of the sheet material. It is to be understood that during formation of a particular notch 146, the projection 112 that is formed on the front end 102 of the longitudinal punching member occupies the space between the portion of the sheet material and the longitudinal member. Due to occupancy of this space, ambient air is dragged within the space during punching operation. This prohibits the portions of the sheet material present adjacent to the impact area from collapsing within the notch 146. As such, the dimensions of the notch 146 do not go beyond the tolerance level. This synchronized operation is repealed until whole of the peripheral portions 150 of the sheet material is punched. The completely punched out sheet material in the form of lamination 152 is shown in FIG. 5. The lamination 152 that is punched out from the notching press is generally used in formation of rotor and stator laminations.
[0022] It will be apparent to those skilled in the art that various modifications and
variations can be made to the present invention without departing from the spirit and scope of the invention. Thus it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents.

We Claim:
I. A notching press tool for punching out rotor and stator laminations from a sheet material rotatably positioned within a notching press comprising:
a longitudinal punch member extending between a front cutting end and a rear end. the rear end being releasably insertable into a punch holder and front cutting end protruding outwardly from the punch holder, the front cutting end having a projection sufficiently formed thereon; and
a die having a slug passage formed therethrough that conforms the longitudinal punch member, the die attached to a die bed and having the sheet member positioned thereon that is rotatable in stepped manner, the die bed and the punch holder capable of cooperating with each other along a punching axis to sequentially form a plurality of spaced apart notches on the rotatable sheet material, the projection occupying space between the front cutting end and a portion of the sheet material while forming a corresponding notch.
2. The notching press too! according to claim 1, wherein one of the pair of opposite sides of the punch member extending along a length thereof has a cutting rib formed thereon, the cutting ribs allowing a pair of opposite depressions formed within the notch during punching operation.
3. The notching press tool according to claim 1, wherein the punch holder includes a stepped portion formed thereon, the stepped portion having a central slot formed therein for releasably positioning the rear end of the longitudinal punch member therein.

4. The notching press tool according to claim 3, wherein the die bed is formed in a stepped
configuration to match the stepped portion of the punch member during notch formation on the
sheet material.
5. The notching press tool according to claim 4, wherein the die bed includes a pair of guide rods
releasably attached thereto and the punch holder has a pair of guide holes formed therein, and
wherein the pair of guide rods is received within the corresponding guide holes to provide a
controlled relative movement between the punch holder and the punch plate during punching
operation.