FIELD OF THE INVENTION
This invention relates to fixtures for heat treating furnaces and more
particularly to multilayer fixtures having one or more tiers, as desired.
10 .
BACKGROUND OF THE INVENTION
Various metal fabricated parts are heat treated, after or before the
15 machining operations, to modify the physical and mechanical properties of the
work piece. The heat treatment process contemplates the placement of the
fabricated metal work piece upon a heat treatment fixture which is inserted into a
furnace to raise the temperature of the fabricated part and fixture to a
predetermined level within a specific time interval. Subsequently, the fabricated
20 products are cooled or quenched within a predetermined time period to yield the
desired physical properties to the prefabricated products.
Heat treatment fixtures are being fabricated from heavy solid member of
metal; they required a large amount of heat energy to be transferred to the same
during the heat treatment process, which increases the cycle time of heat
25 treatment.
Further, in view of the heavy structure of the prior art heat treatment
fixtures, it is extremely difficult to manually insert within the heat treatment
furnace. In addition, such prior art fixtures have typically been expensive to
fabricated as well as subsequent repair.
30 As such, there exists a need for an improved heat treatment fixture which
is relatively lightweight and economical in use, is capable of withstanding the
thermal expansion encountered during heat treatment process without damage
and which may be rapidly repaired and modified to meet the particular heat
treatment production requirements.
35
Annexure‐II
SUMMARY OF PRESENT INVENTION
In 5 accordance with one aspect of present invention is to provide a
Multilayer fixture for heat treating furnace which is simple in construction and are
arranged in multilayer of support plate to support and hold the work piece.
In accordance with second aspect of present invention is to provide a
Multilayer fixture for heat treating furnace having low fixture mass that reduces
10 heat treatment cycle time.
In accordance with another aspect of present invention is to provide a
Multilayer fixture for heat treating furnace that have a greater ease of assembly
and disassembly of fixture.
In accordance with another aspect of present invention is provided a
15 Multilayer fixture for heat treating furnace which retain high strength and rigidity
in assembled condition.
In accordance with another aspect of present invention is provided a
Multilayer fixture for heat treating furnace that can be increased/decreased in
20 length and/or volume easily to accommodate fluctuation in production
requirement.
In accordance with yet another aspect of present invention is to provide a
Multilayer fixture for heat treating furnace to hold the thin walled rectangular
shaped work piece of large size and in multiple quantities, to eliminate the
25 chances of deformation and bending of work piece during Heat treatment.
Other objects and advantageous features of the heat treatment fixture will
be apparent from the description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
30
The features and advantages of the present invention will become more apparent
and descriptive in the description when considered together with figures/flow
charts presented:
Fig. 1 is a Sectional front view of multilayer fixture for heat treating furnace.
35
Annexure‐II
Fig. 2 is a Top view of multilayer fixture for heat treating furnace.
Fig. 3 is a detailed view of Base for holding the component.
Fig. 4 is a detailed view of clamp plate.
5
DETAILED DESCRIPTION
Referring now to Fig. 1, Fig.2, Fig.3 & Fig.4, there is illustrated a preferred
embodiment of the present invention as it would be used in a heat treating
10 furnace, designated generally by reference numeral 11. Multilayer fixture for Heat
treating furnace 11 is designed to hold the Work piece 12 in the fixture in
maximum quantity in one setting.
The metal work piece 12 to be heat treated in the preferred embodiment is
an aluminum alloy thin walled rectangular shaped machined casting used on
15 aircraft’s avionics system. It is to be understood however, that the invention has
application to a specimen constructed of any metal or alloy.
Multilayer fixture for heat treating furnace 11 Comprises a Base Plate 1 of
EN8.Base plate 1 is having two opposite Surface A & Surface B. Surface A &
Surface B of the base plate 1 are substantially flat and parallel. Four Special
20 studs 6 are fixed on the Surface A of Base Plate 1 through four threaded holes
13 made in the base plate. Two nos. of rectangular through pocket 14 are made
in base plate 1 to reduce the weight of the base plate 1. Three threaded Holes 15
are also made in base plate 1 that facilitates the clamping of work piece 12
Assembly with clamp plate 2. Surface B of the Base Plate 1 is adapted to rest in
25 the Furness.
The clamp plate 2 made of EN8, Locates and holds the work piece 12 and
have two numbers of rectangular through pockets 16 to reduce the weight. Three
through Holes 17 are also made in clamp plate 2 that facilitates the clamping of
work piece 12 with clamp plate 2. clamp plate 2 properly locate & clamped the
30 work piece with Allen head screw 4 and washer 8 with Base 3 for supporting
and resting of work piece 12 .
Base 3 for supporting and resting of work piece 12 made of EN8. Base 3
is guided and slides through special stud 6. To accomplish this purpose, four
through holes 18 are fabricated in base 3. Two numbers of rectangular through
35 pockets 19 made in Base 3 to reduce the weight of the Base 3. Work piece 12
Annexure‐II
and Clamp Plate 2 are clamped on Base 3 by Allen head screw 4 and washer 8
in three threaded holes 20 made in Base 3.
Multilayer Heat Treatment Fixture 11 Comprises a Bush 5 made of EN8.
Bush 5 works as a spacer and provides proper 5 oper gap between two layer of base 3
and clamp plate 2 arranged to hold the work piece 12.
Special stud 6 of made of EN8. Four studs 6 fixed on the surface A of the
base Plate 1 through four threaded holes 13 made in Base Plate 1. Stud 6 hold,
position and guide the Base 3 and Bush 5 during assembly and finally clamped
10 multilayer assembly of work pieces with standard nut 7.
Component 12 required to heat treat are clamed between Clamp plate 2
and base 3 by the Allen head screw 4 and washer 8. Then multiple work pieces
are arranged in the stud 6 fixed in the base plate 1, in many tiers. Gap is
provided between successive ties by bush 5. Finally all tiers are hold together
15 with the standard nut.

WE CLAIMS:-
Accordingly, the description of the present invention is to be considered as illustrative only and is for the purpose of teaching those skilled in the art of the best mode of carrying out the invention. The details may be varied substantially without departing from the spirit of the invention, and exclusive use of all modifications which are within the scope of the appended claims is reserved. We Claim

1. Multilayer fixture for heat treating furnace for holding the thin walled rectangular shaped work piece of large size and in multiple quantities adapted to be positioned on heat treatment furnace. The fixture comprising:
- Base Plate that supports other sub component of fixture and acts as base for the fixture.
- Clamp plate used to position and clamping of thin walled rectangular shaped work piece of large size the thin circular metal specimen.
- Base for supporting, positioning and holding the work piece with clamp plate.
- Bush for providing the gap between to successive layer of base and clamp plate assembly.
- Special stud to hold position and guide the Base, clamp plate and work piece assembly, and Bush during assembly of fixture and finally clamped multilayer assembly of work pieces with standard nut.
2. The Multilayer fixture for heat treating furnace of claim 1 wherein, the base plate of the fixture are substantially flat and parallel and adapted to the work surface of the heat treatment fixture.

3. The Multilayer fixture for heat treating furnace of claim 1 wherein, the fixture are made of different components and assembled with Allen head screw.

4. The Multilayer fixture for heat treating furnace of claim 1 wherein, the weight of the fixture are reduced by making through pockets in the base plate, clamp plate and base.

5. The Multilayer fixture for heat treating furnace of claim 1 wherein, the successive layer of base and clamp plate assembly is separated by Bush.
6. The Multilayer fixture for heat treating furnace of claim 1 wherein, Special stud to hold, position and guide the Base, clamp plate and work piece assembly, and Bush during assembly of fixture and finally clamped multilayer assembly of work pieces with standard nut. ,TagSPECI:As per Annexure-II