Annexure‐II
FIXTURE FOR HOLDING HOLLOW CASTING IN A MILLING MACHINE
FIELD OF THE INVENTION
5
This invention relates to fixtures for milling machines. More specifically, it
relates to a fixture, which may be used to hold and locate hollow casting of
various shape and size. Fixture used to hold the hollow casting in manners that
10 all reference surfaces given on casting are in proper positioned for the multi axis
machining of the casting.
.
BACKGROUND OF THE INVENTION
15 This invention pertains to fixtures for holding the hollow casting on milling
machine, and more particularly to a holding fixture adapted to support work to
be machined and locate it relative to the cutting tool. An object of this invention is
the provision of a new and improved hollow casting holding fixture for milling
machine which is rigid, rugged, compact, and capable of high precision holding of
20 hollow casting. This fixture helps to minimize the setup time and maximize the
productivity.
.
SUMMARY OF PRESENT INVENTION
25
In accordance with one aspect of present invention is to provide a fixture
that facilitates holding of a hollow casting in a milling machine and supporting the
walls of the casting thereof while the casting is being machined to a
predetermined shape and size.
30 In accordance with second aspect of present invention is to provide a
fixture for holding hollow casting for accurate positioning of hollow casting on
fixture with respect to dilling face of fixture.
In accordance with another aspect of present invention is provided a
fixture for rigid clamping of hollow casting.
Annexure‐II
In accordance with yet another aspect of present invention is to provide a
fixture for holding hollow casting adapted to be fixed on the bed of milling
machine.
In accordance with yet another aspect of 5 present invention is to provide a
more rigid fixture to hold the hollow casting.
. In accordance with yet another aspect of present invention is to provide a
fixture for holding hollow casting having a dialing face on base plate.
In accordance with another aspect of present invention is to provide a
10 lighter fixture to hold the hollow casting.
In accordance with yet another aspect of present invention is to provide a
fixture that can be properly and effectively utilized to hold and firmly fixed the
hollow casting by lesser skilled individuals.
In accordance with yet another aspect of present of invention is to provide
15 a fixture for holding hollow casting that have spring loaded clamp at height to
eliminate the loosening of clamps due to vibration.
BRIEF DESCRIPTION OF THE DRAWINGS
20
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:
25 Fig. 1 is a Sectional Front view of fixture for holding hollow casting
Fig. 2 is a Top view of fixture for holding hollow casting
Fig. 3 is a Sectional side view of fixture for holding hollow casting
30
Annexure‐II
DETAILED DESCRIPTION
Referring to fig. 1, 2 & 3 present invention is a fixture 23 used to hold and
position the hollow casting and adapted for use on multi axis milling 5 machine.
The fixture 23 is designed to hold the hollow casting 24 within dimensional
tolerance with respect to dialling face 26 of fixture 23.
Fixture 23 for holding a hollow casting 24 comprises a base plate 1 having
a substantially flat top surface A and bottom surface B. Base plate is made of
10 mild steel of 40 mm thickness. Surface B of base plate, rest on milling machine
bed. Fixture 23 is fixed on the milling machine bed 27 with the help of four
through counter bore holes 25.
Hollow casting 24 rest on surface A of base plate 1 located in desired
place by a diamond pin 11 & a locating pin 10. Diamond pin 11 & a locating pin
15 10 are fixed on surface A of base plate 1 to position the casting with reference to
the dialling face 26 for milling operation. Surfaces A & surface B of the base
plate 1 are made parallel within 0.020 mm by grinding the both surfaces. Hollow
casting 24 clamped on base plate 1 by clamp 4 & clamp 5 with special support
block 3 to support the clamp at height. Allen head screw 19 is used as heel
20 screw for clamp 4 and Allen head screw 14 is used as heel screw for clamp 5.
Allen head screw 18 is used as clamping screw to provide clamping force to
clamp 4 and Allen head screw 13 is used as clamping screw to provide clamping
force to clamp 5.
Hollow casting 24 is supported at top in between of upper clamp and lower
25 clamp plate 9, two Allen head screw 16, Spaces 7,8, compression spring 22 on
support block 2 which is fixed to the surface A of base plate 1.Four Allen head
screw 12 is used to rigidly fix the support block 2 with base plate 1. Allen head
screw 16 is used to provide desired compression to the spring 22.This spring 22
provides the continuous force to camp plate 9 that eliminate the possibility of
30 loosening of clamp plate 9 during milling operation due to induced vibration of
milling machine and cutting forces.
Dialing face 26 in base plate 1 used as a datum for the manufacturing of
fixture 23 to maintain the position of all the items as describe above with in the
geometrical tolerance .This dialing face 26 is used to position the fixture on
35 milling machine bed parallel to any one axis of the milling machine.

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. A fixture for holding hollow casting and supporting the wall of casting adapted to be positioned on work table of milling machine. The fixture comprising:
- Base Plate adapted to be coupled to the bed of milling machine and provides supporting surface to other sub component of fixture. Hollow casting rest and positioned on the top surface of base plate.
- One pillar that is rigidly coupled to the top surface of the base plate with Allen head screw.
- Location Pin and Diamond pin that guide the casting to remain in pre determined position with respect to dialling surface and prevent the X ,Y direction movement of hollow casting.
- Spring loaded clamp plate on the top of pillar to eliminate the possibility of loosening of clamp during milling operation due to induced vibration of milling machine and cutting forces.
- Clamp to securely hold the Hollow casting on fixture.
2. The fixture for holding hollow casting of claim 2 wherein, top and bottom surfaces of the base plate are substantially parallel.
3. The fixture for holding hollow casting of claim 2 wherein, bottom surface of the base plate is adapted to positioned and clamped on the milling machine bed.
4. The fixture for holding hollow casting of claim 2 wherein, base plate is having four counter bore holes on base plate for fixing the fixture on machine bed.
5. The fixture for holding hollow casting of claim 1 further comprising a dialling face that provides reference edge for the other sub component of fixture.
6. The fixture for holding hollow casting of claim 1 further comprising a pillar rigidly clamped and supported on base plate and provides clamping feature to spring loaded clamps.
7. The fixture for holding hollow casting of claim 6 further comprising a spring loaded clamps at the top of pillar to eliminate vibration on top part of hollow casting and the loosening of clamps due to vibration.