The present disclosure relates to method of forming negative draft in gear lugs without removing material, and in particular relates to the method of forming negative draft along the depth of the solid projections, when seen from the top, protruding from the metallic object, either on the face or on the outer edge of a solid metallic object or on the inner surface of a hollow metallic object.
Background of the Invention:
The conventional method of manufacturing negative draft on lugs is through removing material through cutting tools. As a result it is required in the preceding operation to have extra material for allowance as per the cutting tools employed. The material removal operation using cutting tools to form the negative draft on the lug is usually carried on a computer numerically controlled machine. The conventional methods employed to form negative draft of lugs involve some other drawbacks like high tool cost, lower specific strength and low tool life. The time required to manufacture the negative lugs through removing material through cutting tools is high. There is always extra material required in the machining process to form the negative draft on the lug, therefore the weight of the material before negative draft manufacturing is more than material after negative draft manufacturing when manufactured via conventional machining operation.
Accordingly, a need remains for tools and tool systems that address many if not all of these deficiencies, and which provide greater flexibility and ease of use for an operator.

Objective of the invention;
The primary objective of the present invention is to propose device and method to manufacture the negative draft in a gear lug on a metallic object without removing material through cold forming and substantially overcomes the above mentioned disadvantages of the aforesaid conventional methods.
Summary of the invention:
The following summary is provided to facilitate an understanding of some of the innovative features unique to the disclosed embodiments and is not intended to the full description of the invention. A full appreciation of the various aspects of the preferred embodiments disclosed herein can be gained by taking the entire specification, claims, drawings and abstract as a whole.
The main object of the present invention relates to provide a device for the negative draft forming in a lug on a metallic object without removing material through cold forming.
Another object of the present invention is to provide a device, which includes a metallic disc shaped object and a punching object for the negative draft forming.
Yet another object of the present invention is to provide a device, which is operated by power press specifically hydraulic press is used.
Still yet another object of the present invention is the time required to form negative draft on a lug via cold forming is significantly less than the time required to remove the material.
Another object of the present invention is subjected to change in weight of material by cold forming method is employed to form negative draft on the lugs.

Other features and advantages of the present invention will become more apparent from the following detailed description, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
Brief description of the accompanying drawings:
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the
present disclosure.
Figure 1 is sectional view of the punching object and segmented die set-up on power press, when viewed from front.
Figure 2 illustrates the top-section view of the segmented die on power press;
Figure 3 depicts the top view of the metallic disc shaped object for use in the practice of invention, to show reference illustration of the lug in the surface of the metallic object, which can be formed by any conventional manufacturing method.
Figure-4 depicts the front view of the lug having 90 degree angle with the surface of the metallic object;
Figure-5 depicts the top view to show reference illustration of the lug having a negative draft;
Figure- 6 depicts the front view the angle of the vertical profile of the lug with the face of the lug is below 90 degree angle with the surface of the metallic object.
Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

Detailed description of the invention:
The preferred embodiments will now be described more fully with reference to the accompanying drawings. The embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth as specific components, devices, and methods, to provide a thorough understanding of preferred embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that preferred embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
In the preferred embodiment of the present invention is the device for forming negative draft in lugs without removing the material.
Another preferred embodiment of the present invention is a method of forming negative draft along the depth of the solid projections, when seen from the top, protruding from the metallic object, either on the face or on the outer edge of a solid metallic object or on the inner surface of a hollow metallic object.
Referring to Figure-1, the punching object (1) is described in the present invention, is comprised; an upper, middle and lower pressure pad (2, 3 and 4), an outer punch (5), an inner punch (6), a tapper segment (7), a tapper ring (8) and a base spring (9).
Now referring to Figure-2, the metallic disc shaped object (10) in accordance of the present invention, is comprised; a plurality of segments (11), a spring (12), a negative draft (13), a plurality of lug (14) and a die cavity (15).
Further with the reference of Figure 3-6, view to show reference illustration of the lug having 90 degree angle with the surface of the metallic object, showing a lug (14), a plurality of segment (12) and a negative draft (13).

According to the preferred embodiment of the present invention, the force from the press is transferred to the punch through component (2), (3), and (4), as seen in Figure 1 and Figure 2. As the outer punch (5) moves down, and the pressure is applied on the inner punch (6), each segment (11) is pushed downward. Each segment (11) is tapered along the length on the outer diameter. The base spring (9) is provided to allow the segment (11) to return to original position on completion of the stroke. The tapered profile on the taper ring (8) is the mirror image of the taper profile on the taper segment (7). Due to this taper profile, the segments (11) move in linear direction along the z-axis, simultaneously converging on the lug profile of the part. The spring (12) as shown in image 2, is compressed, and the circumferential gap between each segment (11) gets gradually reduced. The lug (14) is pressed by the negative draft (13) profile in the die cavity (15), as shown in Figure 2, and formed as per the shape of the negative draft profile (13) in the die cavity (15). The base springs (9) gets compressed during the downward stroke, and facilitate the return of the segment (11) to its original position along the z-axis. The inner punch (6), which rests on the top of the segments (11), also gets pushed upwards, to enable ejection after the process is completed. Also, the circumferential gap between tapered segments (7) increase as segments (11) diverge, during the upward movement of the outer punch (5). This convergence and divergence of segments (11) is possible because of the spring (12), to facilitate the opening and closing of the segments (11).
The section view in Figure 2 shows the view of the die when viewed from top. The metallic disc shaped object (10) is a segmented die and the number of segments (11) depends on the number of lugs (14). The spring (12) is facilitating the opening and closing of the segments (11). The negative draft profile (13) is in the die cavity (15). The lug (14) to be formed is placed in the centre by the operator, before actuating the downward stroke in the press.
More specifically and referring to the Figures 3-6 of the present invention, disclosed herein specifically Figure-3 shows top view of a metallic disc shaped object (10) accompanying with lugs (14) having 90 degree angle with the surface of the metallic
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object (10), which can be formed by any conventional manufacturing method. The top view of a segment (11) in the figure-4 is shown in figure-2 depicts the lug (14) having 90 degree angle with the surface of the metallic object (10).The Figure-5 shows top view of the metallic disc shaped object (10) accompanying with the lugs (14) having a negative draft (13) i.e. the angle of the vertical profile of the lug (14) with the face of the lug (14) is below 90 degree and the top view of a section of the Figure-5 is shown in Figure -6 which depicts the lug having a negative draft (13).
The main advantages of the present invention are:
Provide method takes less time to manufacture the negative draft on a lug via cold forming, which is significantly less than the time required to remove the material.
The tool life of cold forming dies is significantly more than the cutting tools, thereby reducing the tool cost/part. The cold forming of the negative draft is proposed to be carried out on a hydraulic press.
The hourly cost to run the computer numeric controlled machine is significantly more than the hourly cost to run a hydraulic press.
The weight of the material before negative draft manufacturing is more than material after negative draft manufacturing when manufactured via machining operation. There is no change in weight when cold forming method is employed to form negative draft on the lugs.
The piece of metal formed through cold forming has a higher specific strength than the metal piece, which is machined. The major function of the lug is to facilitate synchronous movement of a mating part, which has matching holes. These parts when used in machinery, experience significant magnitude of stress.
Although a preferred embodiment of the invention has been illustrated and described, it will at once be apparent to those skilled in the art that the invention includes advantages and features over and beyond the specific illustrated construction. Accordingly it is
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intended that the scope of the invention be limited solely by the scope of the hereinafter appended claims, and not by the foregoing specification, when interpreted in light of the relevant prior art.

We Claims:

A device for forming a negative draft (13)in a lug (14) on a metallic object (10), comprising;
a punching object (1) having upper, middle and lower pressure pad (2,3 and 4), an outer punch (5) and a inner punch (6), a tapper segment (7), a tapper ring (8), and a base spring (9),
wherein said negative draft (13) is formed in a lug (14) on a metallic object (lO)without removing material through cold forming, said metallic object (10) accompanying with lugs (14),further, comprising; a plurality of segment (11), a spring (12), a lug (14) and a die cavity (15).
The device as claimed in claim 1, wherein force is transferred through said upper,
middle and lower pressure pad (2,3 and 4).
The device as claimed in claim 1, wherein said tapper segment (7) pushed
downwards by pressure applied on said inner punch (5).
The device as claimed in claim 1, wherein said segment (11) is tapered along the
length on the outer diameter.
The device as claimed in claim 1, wherein said segment (11) comes in original
position after completion of stroke by said base spring (9).
The device as claimed in claim 1, wherein said spring (12) facilitates the opening
and closing of said segment (11).
The device as claimed in claim 1, wherein said lug (14) is pressed by said negative
draft (13) in said die cavity (15).
A method to manufacture a negative draft (13) in a lug (14) on a metallic object
(10) wherein said negative draft (13) is formed in a lug (14) on a metallic object
(10) without removing material through cold forming and to be carried out on a
hydraulic press.

The method to manufacture a negative draft as claimed in claim 8, wherein said method is employed to along the depth of the solid projections, when seen from the top, protruding from said metallic object (10), on the face or on the outer edge of a solid metallic object (10).