FORM 2
THE PATENTS ACT, 1970
(39 of 1970) & The Patents Rules, 2003
PROVISIONAL/COMPLETE SPECIFICATION
(See section 10 and rule 13)
1. TITLE OF THE INVENTION
Fixture for Holding Washers in Anodizing Process
2. APPLICANT(S)
(a) NAME: HINDUSTAN AERONAUTICS LIMITED
b) NATIONALITY: INDIAN
(c) ADDRESS: Hindustan Aeronautics Limited, Ojhar, Nashik, Maharashtra.
3. PREAMBLE TO THE DESCRIPTION
PROVISIONAL The following COMPLETE The following specification
specification describes the particularly describes the invention and
invention. the manner in which is to be performed.
X V
4. DESCRIPTION (Description shall start from next stage.)
Refer Annexure I
5. CLAIMS (Not applicable for provisional specification. Claims should start
with the preamble - "i/We claim" on separate page)
Refer Annexure II
6. DATE AND SIGNATURE (to be given at the end of last page of specification)
7. ABSTRACT OF THE INVENTION (to be given along with complete specification on separate page)
Refer Annexure III


1 Title of the Invention
Fixture for Holding Washers in Anodizing Process.
2 Field of the Invention
The invention relates to the anodizing operation. It is an electrolytic process carried out to improve physical and chemical properties of the component which are washers in.this case. The scope of the invention extends to all the industries where such an electrolytic process is carried out.
3 Background of the Invention
Corrosion is actually one of the main problems faced in overhaul and maintenance of fighter aircraft. Factors like humidity, frequent washing and temperature difference inevitably increase the amount' of corrosion in aircraft parts. The corrosion problems encountered affect the load carrying capability of the aircraft and also increases the probability of crack formation on aircraft structure. Regular corrosion related checks are performed by maintenance team which attributes to 10% of the total maintenance cost.
To protect the aircraft parts from corrosion anodizing process is carried out on parts which are more prone to corrosion. Problem taken up is related to anodizing done on washers which are commonly used in each and every assembly of aircraft system thus, swift supply of washers is necessary. The major challenge in this area is to reduce rework and save time while improving the quality of anodized washers. The existing anodizing process reduces production rate and rework increases the production cost. The development of new fixture has resulted in significant saving per annum as tangible benefits as well as improved anodizing has increased washers life. • Customer satisfaction has energized us and motivated our team spirit as a part of intangible benefits.
3.1 Prior Art
In existing anodizing process two different methods were used for holding or clamping the washers to be anodized.,

The first one is Wire Clamping Method .Wire clamping is the traditional method used for holding the small washers by the user shop. In this method an aluminum wire is used for holding the washers. All the washers are inserted in the wire one by one and then wire is bent in U-shape formation making two equal half. This U-shape formation is then twisted in such way that all the washers are packed in very closely. This bunch of washers is then immersed in anodizing tank solution for further process. There are some disadvantages of using this method. As thin aluminum wire is used for holding it tends to break continuously. All the washers were not used to get tightly packed leaving discontinuity in the process flow current. Due to this burn marks and large number of non-anodized washers are observed. Operator fatigue was observed due to large quantity of washers. Another method used for clamping or holding the washers is Spring Clamping method. In this method an Aluminum spring also called as 'Working Coil' which is thick and long in nature having firm spring tension is used. Washers to be anodized are inserted in this Working Coil with the help of a small screw driver along the periphery of the spring one by one manually in staggered position. After positioning the washers working coil is immersed in anodizing tank solution and anodizing process is carried out. There are some disadvantages of using this method.In this method partial part of the washer which is clamped in the working coil remains un-anodized. As the same working coil is used repeatedly its thickness gets affected by the etching effect. This leads to reduce spring tension thus washers falling in solution tank. Fixture marks are also observed in this method. Percentage of rework is on the higher side in this method.
As it is a manual process two operators are continuously engaged in this method.
4 Brief Summary of the Invention
The following specification particularly describes the invention and the manner in which it is to be performed. Entire fixture is fabricated from

Titanium material to eliminate the effect of etching on the fixture body from anodizing solution. It also ensures the long life of fixture. Titanium material also ensures the smooth flow of current through fixture for the anodizing operation.
The new operational procedure is developed and is being followed by the user shop. The fixture is adjusted as per the given diameter of washer by simply adjusting the distance between support plates with the help of special bolt. Washers are inserted in the V-grooves one by one manually. Fixture is then tightened and top plate is also mounted on the fixture. Fixture is finally mounted on the holder and anodizing process is carried out as per technology.
5 Detail Description of the Drawings
Figure 1 shows the complete fixture drawing consist of base plate (1), ,support plate (2), top plate (3), bolt (4) ,bush (5), studs (6), locating pin (7), nut (8) and ,washer (9).
Figure 2 shows special bolt (4) and bush (5) which was designed to accommodate different diameters of washers to be anodized.
Figure 3 shows top plate (3) having slots machined on it. It locks all the washers against the base plate (1) so that all the washers are packed closely and prevents washers falling in to solution tank.
Figure 4. shows base plate (1) is used in the fixture which is welded to one of the top plate (3). The main function of base plate (1) is to prevent the washers from falling in to the solution tank while anodizing,.
Figure 5 shows support plates (2) used in the fixture. There are two support plates (2) used in the fixture one on top side and the other on bottom.

5 Detail Description of the Invention
There are several types of washers used in large quantity on the Aircraft are prone to corrosion and they are required anodizing. In order to achieve appropriate anodization of the washers, a specific fixture is developed to perform the process. The embodiment provided here under discloses the features of the fixture and the process.
A special bolt (4) and a bush (5) are designed to accommodate different diameters of washers to be anodized. Head of the special bolt (4) is provided with an ergonomics shaped knob on one side to enable operations for easy clamping and unclarnping purpose. Bolt (4) disclosed throughout in this embodiment is treated as a special bolt within the scope of this invention. Bush (5). is welded to the support plate (2) to keep only one support plate movable.
There are two support plates (2) used in the fixture one on top side and the other on bottom. Each support plate (2) has V-grooves machined on one side through entire length having included angle of 30 degree. V-grooves are machined on the support plates (2) to minimize the contact area between support plate (2) and washers to be anodized so that fixture marks on the washers are not imprinted. There are total of 28 V-grooves on the support plate (2) and possibly large number of washers can be accommodated in a single set up. This fixture can accommodate washers from minimum 5mm diameter to maximum 50 mm diameter.
One base plate (1) is used in the fixture which is welded to one of the support plates (2) and it is mostly with bottom. However, base plate (1) can also be welded to top support plate (2). The main function of base plate (1) is to prevent the washers from falling in to the solution tank while anodizing.
Top plate (3) is also provided for the fixture having slots machined on it. Top plate (3) performs two functions at a time. It locks all the washers against the base plate (1) so that all the washers are packed closely and

smooth flow of current passes through washers. It also prevents washers falling in to solution tank. Slots are machined on one side of top plate (3) for adjustment purpose for accommodating different diameters of washers. Studs (6) are provided for the clamping purpose of top plate (3) and four locating pins (7) are provided which are fixed to one of the support plates (2). Locating pins (7) guides the moving support plate. Springs are provided in between support plates (2) around the locating pins which applies the uniform pressure on to the support plate (2) while clamping and unclamping. Springs are coated with EP-215 primer to protect them from etching effect.

7 Drawings



Figure 2

Figure 3


Figure 4

Figure 5
*

Title: Fixture for Holding Washers in Anodizing Process
We Claim,
1. Fixture for Holding Washers in Anodizing Process comprising:
a Base plate (1), Support Plate (2) in-plurality, Top Plate (3), Special Bolt (4), Bush (5)\ Stud (6), Locating Pins (7), Nut (8) and Washer (9);
wherein assemble of the said fixture is by aligning said base plate (1) and said support plate (2) with the help of said locating pin (7);
wherein said washer (9) held in fixture by tightening and adjusting said special bolt.(4);
wherein said top plate (3) is used for tightening said washer (9) in place to prevent falling said washers (9) in to solution tank; and
wherein said locating pins (7) are provided for guiding support plate and said studs (6) are provided for the clamping purpose.