FORM - 2
THE PATENTS ACT, 1970
(39 of 1970)
AND
THE PATENTS RULES, 2003 COMPLETE SPECIFICATION
(See Section 10; Rule 13)
1. TITLE OF THE INVENTION:
"A novel Cartesian grid structure for large format moving bridge machining centers by inventing a floating tie Beam"
2. APPLICANT:
(a) NAME: CLASSIC AUTOMOTIVE INDUSTRIES P. LTD.
(b) NATIONALITY: AN INDIAN COMPANY INCORPORATE UNDER
THE COMPANIES ACT, 1956.
(c) ADDRESS: Plot No.62: Block No-F-11,
MIDC, Pimpri, PUNE-411 018, MAHARASHTRA, INDIA.
The following specification describes the nature of the invention and the manner in which it is to be performed:-

3. PREAMBLE TO THE DESCRIPTION
Field of Invention
The present invention relates to a novel relates to a novel Cartesian grid structure for large format moving bridge machining centers by inventing a floating tie Beam / Third Box for the existing box in box construction leading to a new box in box in Box / Box 3 / Box cube for serial or parallel kinematic or hybrid kinematic architecture machine tools.
Background of the Invention & the Related Art
For the easy understanding of the background of the invention & the related prior arts the description of figures relating to the same is as follows:
1. Example of Cartesian Structure.
2. Example of Serial architecture.
3. A Classic Hexapod Construction for a parallel architecture machine.
4. A Classic example of a hybrid machine.
5. A Box in Box Structure.
6. The force application on a box in box construction.
7. A planno-miller.
8. A classical piano-miller, the concept of moving gantry machine.
9. A classical moving bridge machine.
10. A box in box moving bridge machine.
11. Loading & unloading of large components in a Box in Box machine.

12. Loading & unloading of large jobs in a Classical moving bridge machine.
13. Visualization of the vibrations caused in classic bridge moving machine.
14. Visualization of the vibrations caused in Box in Box bridge moving machine.
Before commencing with the background of the invention under consideration certain engineering terms used and their graphical representation in brief is as follows:
a) Cartesian grid structure - A Cartesian grid is a special case where the elements are unit squares or unit cubes and the vertices are integer points. An example of a Cartesian Structure is given in figure no. 1.
b) Serial Kinematic Architecture - It is the most common design where one moving member is placed on the other and finally all assembled members are placed on a fixed base. An classic example of a serial structure is given in figure no. 2.
c) Parallel Kinematic Architecture - In this design all the moving members are independently held on one plane and the point of contact with the plane also as a load member and also a suspension pivot for that member. A classic Hexapod Construction for a parallel architecture machine is given in figure no. 3.
d) Hybrid Kinematic Architecture - As the name suggests it is a combination of both Serial and parallel architecture. In figure no. 4 a classic example of

a hybrid machine is given. It is worth mentioning here that, this machine has a monocock structure and the serial architecture X Y table is enveloped by this monocock structure.
e) Box in Box Structure - As the very name suggests in this structure one box is placed inside another box and the sliding movement is achieved in such a way that the inner box is never outside the outer box and the combined structure gives the best rigidity known in serial kinematic architecture. An example of this structure is given in figure no. 5.
The force application on a box in box construction - in the figure no. 6 it is shown that there is a minimal deflection, as the structure has no movement and the load carrying member is moving on guides forming a box in box structure.
Now let's discuss about the various existing prior arts:
1. The machining of large components has fascinated the minds of inventors since the start of the first Industrial revolution. This fascination led to the invention of large planers and piano-millers. The cutting tool / milling tool technology of that time did not support high rotational cutting speeds and High Linear cutting feeds and hence all the milling operations were being performed by high rotational torque to the cutting tool / milling tool, at low linear feed rates but had reasonably good depth of cuts. These machines had guide ways and keeper plates for movement. A planno-miller is shown in figure 7 as an example in the case.
2. All these machines were built on the classical serial kinematic architecture. They had the inherent problems of serial kinematic architecture. To minimize

the effects of these inherent problems of the serial kinematic architecture, the structures to hold the milling heads were made very heavy. These structures on which the milling heads moved were fixed to the bed way. On this bed way was placed the bed on which the work piece / job was paced. Such classical machines usually needed to perform the milling operations at cutter rotational speeds of about 300 RPM and cutting feeds of about 1 to 1.5 meters per minute (depending on the cutter size and cutter material).
3. With the developments in cutting tool technology the rotational cutting speeds and Linear cutting feeds of the machine needed to increase. As it was extremely difficult to move the bed along with the large work piece at desired feed speeds in the classical piano-miller, the concept of moving gantry machines was developed. Here, as shown in figure 8, the machine worked on the principles wherein the gantry moved on 2 separate ly ' axis and the work table or bed was stationary. Along with the normal milling operations, this design also led to the concept of 5 face and of large components as the large work piece could be machined on all the five exposed faces in one set-up by using manually indexing heads or auto indexing heads. This 5 face and machining concept also demanded that, the X axis of the gantry be made large enough so as to accommodate the manual / auto 5 face machining heads. Such millings were carried on materials like castings and steels so the operations required the moderate rotational cutting speed and moderate linear cutting feed (moderate compared to the current day's). The Moving Gantry machines operate at linear feed rates of about 5 to 8 mtrs per minute. These machines have hardened and ground box ways or Linear Motion Guide ways and roller or ball packs for getting the desired motion.

Moving bridge Machines:
1. With the passage of time demand for increased linear speeds and increased accelerations for high speed machining along with the need for higher rotational speed of the cutter for machining materials like titanium, aluminum, composites of various grades including carbon fiber grew and led to the concept of moving bridge machines. The complexities involved in machining these materials and intricate profiles lead to the development of 5 axis machining, thus the need for a larger X axis persisted. Today moving Bridges machines are capable of moving at about 15 to 20 Meters per minute with ball screw and ball nuts and the bridge speeds of about 25 to 30 meters per minute are achieved on rack and pinion drives. These machines have linear motion guide ways and roller or ball packs for getting the desire motion. The cutting rotational speeds are to the tune of about 8000 RPM to 24000 RPM depending on the material to be cut.
There are two types of constructions in the moving bridge machines:
A. Classical moving bridge machines
B. Box in Box moving bridge machines
Classical moving bridge machines:
The Classical moving bridge machines are the most common machines. There, the Z axis is suspended from the outer face of the moving Bridge. These machines have a linear motion guide ways and roller or ball packs for getting the desire motion. This design is hugely susceptible to the inherent issues of serial kinematic architecture and to overcome these, the serial members of the machine are made extremely rigid and heavy. Moving these machines at high speeds and high

accelerations calls for high structural dynamic properties in all serial members & this leads to the requirement of high stiffness in all the serial members. This requirement of High stiffness further adds to the weight of the serial members. A classical moving bridge machine is shown in figure 9.
Box in Box moving bridge machines:
A box in box moving bridge machine is shown in figure 10. As shown in the said figure, in the Box in Box moving Bridge machines, the Moving Bridge has a enclosed rectangular opening inside the bridge and the z axis is passed thru the rectangular opening of the moving Bridge. These machines have a linear motion guide ways and roller or ball packs for getting the desired motion. The Weight of the z axis is loaded on top of the bridge and hence the static loading properties of the moving bridge are very good. Moving these machines at high speeds and high accelerations calls for high structural dynamic properties in all the serial members, leading to requirement of high stiffness in all the serial members. This requirement of High stiffness further adds to the weight of the serial members.
Drawbacks of the existing systems:
1. All the moving bridge machines, classic design machines and box in box design machines are used to machine large components. As shown in the figure 11 (loading & unloading of large components in a Box in Box machine) and figure 12 (loading & unloading of large jobs in a Classical moving bridge machine), the handling of all these components need an overhead crane to enter the stationary bed which is placed between both the Y axis. As the crane needs to enter between both the Y axis, no rigid load carrying member can be connected between both the Y axis so, both the Y axis have to be made strong enough so as to independently support the weight of the X axis and Z axis.

This is one of the major reasons for increase in weight of all Y axis along with the Y axis supports (legs) i.e. the base member of the serial architecture.
2. Further, as both the Y axis members are not connected at the ends and the bridge along with the Z axis which is moving at great linear speeds on linear motion guide ways and roller or ball packs for getting the desired motion and they are driven by either ball screw and ball nuts or by rack and pinion, hence, the machine structure is prone to a lot of dynamic instability, as each of the Y axis tend to vibrate independently. A graphic representation of this dynamic instability and vibrations is shown in the figure 13 (visualization of the vibrations caused in classic bridge moving machine) and figure 14 (visualization of the vibrations caused in Box in Box bridge moving machine). These vibrations have to be accounted for in the designing by adding mass to the serial members and thus further increasing the weight of the machine. These vibrations also affect the surface finish of the machining operation and also reduce the life to the cutting tools / milling tools.
3. Further, to eliminate this problem some smaller moving bridge machines have a monocock machine structure. The monocock structure is usually welded or firmly bolted and dowelled for having the desired rigidity. In such cases the bed/table of the machine along with the work piece is enveloped by the monocock structure and the work piece along with the bed/table is moved out of this monocock structure by way of a pallet changer or some other method. But the size of such machines is limited to just a couple of meters in the longest axis. Such a pallet changing system or any other method is not practical when the machine is a large format machining center, say for e.g. about 10 meters on the Y axis. A typical monocock machine is shown in figure no. 4.

4. DESCRIPTION OF THE INVENTION
The invention under consideration describes a novel Cartesian grid structure for large format moving bridge machining centers by inventing a floating tie Beam / Third Box for the existing box in box construction leading to a new box in box in Box / Box 3 / Box cube for serial or parallel kinematic or hybrid kinematic architecture machine tools.
Description of figures:
15. Moving gantry without floating beams.
16. Moving bridge machine having the third box in box
17. A pair of floating tie beams.
18. Connections of the floating tie beams with the Y axis.
19. Motorized mechanism in the moving bridge machine.
20. Position of the floating tie beams during normal operations at the extreme ends of Y axis.
21. Alternate position 1 of the floating tie beams according to the requirement.
22. Alternate position 2 of the floating tie beams according to the requirement.
23.Fern analysis indicator without floating tie beams. 24. Fern analysis indicator with floating tie beams.
Description of bulleting in the figures:
1. X Axis
2. Y Axis
3. Z Axis

4. Floating tie beam
5. Third box
6. Connection of floating tie beam
7. Connection of X Axis with Y Axis
8. Linear motion guide ways & roller or ball packs or hardened & ground guide ways
9. Connection of ball screws & ball nut on X Axis
10. Closed loop chain or rope for the movement of floating tie beam
11. Connection to closed loop chain or rope
12. Pulley or spigot
13. Motor/Brake Motor/Geared Motor
14. Job / Work piece
15. Crane
16. Y Axis support
Under the normal circumstances, in any moving gantry machine there are two independent Y Axis (2). Further is X Axis (1) having a rectangular opening. The rectangular opening of the X Axis (1) allows the acceptance of Z Axis (3) held over the X Axis (1) by the Z Axis holder or saddle is considered as one box and this box is accepted thorough the X Axis (1) making it a second box. Hence, this is popularly known as Box in Box concept in the moving gantry machines.
In the invention under consideration, two moving tie beams (3) are introduced. These floating tie beams (4) are within the two independent Y Axis (2). Hence, with the help of two independent Y Axis (2) and two floating beams (4) third box (5) is created. The structure within this third box (5) due to use of the floating tie beams (4) becomes similar to the monocock structure of temporary nature/duration. As the structure is similar to the monocock structure of temporary nature/duration restricts & minimizes any potential deflection of the Y Axis (2)

along with the Y Axis supports (16). Because of this the tendency of Y Axis (2) to vibrate independently is reduced substantially. In short this third box (5) structure acts as vibration damper leading to a greater dynamic stability of the whole structure. Also, as the vibrations are reduced there is no need to have heavy weight of the Y Axis supports (16) as was required in the earlier arts.
In the invention under consideration a pair of floating time beams (4) are positioned on either side of the X Axis (1) and are oriented parallel to the X Axis (1). The connection of the floating tie beams (22) with the Y Axis is thru linear motion guide ways & roller or ball packs or hardened & ground guide ways (8). Such a connection is required for getting the desired motion parallel to the X Axis (1) and normal to the Y Axis. It is important to note that, the floating tie beams (4) are not connected to the drive mechanism of the Y Axis i.e. either to the ball screws & ball nut or by rack and pinion.
The movement of these floating tie beams (4) can be done manually by applying pushing force or can be mechanized by fixing a closed loop chain or rope (10) and spigot mechanism or by a closed loop pulley and rope mechanism and providing a handle to the Pulley or spigot (12). The same mechanism can be made motorized by fitting a motor/break motor/geared motor (13) to the spigot or pulley mechanism (12). Once the floating tie beams (4) are in the desired extreme positions, the said floating tie beams (4) are to be locked so that, during the general operation of the machine, the floating tie beams (4) do not move towards the area of operation of the machine, hence, a suitable locking mechanism in place. This locking mechanism can be a small bolt / stopper or other suitable mechanism. For the motorized version, to lock the floating tie beams (4) a break motor (13) instead of a normal motor (13) is necessary to do the job of locking the floating tie beams (4) in the desired position. An important element is worth considering here is that, each floating tie beam (4) is necessary to be in position to

be moved independently, hence two separate mechanisms are necessary for each of the floating time beams (4). As shown in the Figures, one mechanism on one Y axis (2) for one floating tie beam (4) and the other mechanism for the remaining floating tie beam (4) on the second Y axis (2) is there.
The floating tie beams (4) are positioned & connected to the mechanism in such a way that, the same restrict and minimize any potential deflection of the Y axis (2) along with the Y axis supports (16). The floating tie beams (4) also act like the vibration dampers leading to a greater dynamic stability of the whole structure.
Further in the invention under consideration and shown in figure, during the normal operation of the machine each of these floating tie beams (4) will be positioned on the extreme ends of the Y axis (4) this enables to achieve no hindrance to operation of the machine. The floating tie beams (4) along with the two Y axis (2) become the third box for the existing Box in Box construction leading to a new Box in Box in Box / Box 3 / Box cube concept for serial or parallel kinematic or hybrid kinematic architecture machine tools.
When the job / work piece (14) is loaded / unloaded on the bed of the X axis (1) along with the Z axis (3), one floating tie beam (4) is taken to one of the extreme ends of the Y Axis (2) and the remaining floating tie beam (4) is also taken to the other extreme end of the Y Axis (2), so that the same can be brought closer to the X Axis (1). As shown specifically in the figure the crane (15) can enter between both the Y Axis (2) and load / unload the job / work piece (14). Thus, the advantages of a monocock structure when the floating tie beams (4) are locked in their respective positions and the flexibility of sliding the off as and when needed.
It is note worthy that, the Fern analysis of the machine structure with and without the floating tie beam (4) shows that, there is an improvement of minimum of 11 %

in the static stability of the whole structure. The use of the floating tie beams (4) on one hand save the mass of the entire structure by minimum of 11% and on the other hand also gives enhanced static stability by minimum of 11 % to whole of the structure.

5. We claim:
1. A novel Cartesian grid structure for large format moving bridge machining centers by inventing a floating tie Beam / Third Box for the existing box in box construction leading to a new box in box in Box / Box 3 / Box cube for serial or parallel kinematic or hybrid kinematic architecture machine tools.
2. A novel Cartesian grid structure for large format moving bridge machining centers by inventing a floating tie Beam / Third Box for the existing box in box construction leading to a new box in box in Box / Box 3 / Box cube for serial or parallel kinematic or hybrid kinematic architecture machine tools as claimed in claim 1, having two moving tie beams (3) within the two independent Y Axis (2) and hence, with the help of two independent Y Axis (2) and two floating beams (4) third box (5) being created and the structure within this third box (5) due to use of the floating tie beams (4) becoming similar to the monocock structure of temporary nature/duration and hence restricting & minimizing any potential deflection of the Y Axis (2) along with the Y Axis supports (16) and reducing the tendency of Y Axis (2) to vibrate independently substantially, hence acting as vibration damper leading to a enhanced dynamic stability of the whole structure by minimum of 11% and also reducing heavy weight of the Y Axis supports (16) by minimum of 11 %.
3. A novel Cartesian grid structure for large format moving bridge machining , centers by inventing a floating tie Beam / Third Box for the existing box in box construction leading to a new box in box in Box / Box 3 / Box cube for serial or parallel kinematic or hybrid kinematic architecture machine tools as claimed in claims 1 & 2, having a pair of floating time beams (4) being able to be moved manually by applying pushing force or in a mechanized

manner by fixing a closed loop chain or rope (10) and spigot mechanism or by a closed loop pulley and rope mechanism and providing a handle to the Pulley or spigot (12) or the same mechanism being motorized by fitting a motor/break motor/geared motor (13) to the spigot or pulley mechanism (12).
4. A novel Cartesian grid structure for large format moving bridge machining centers by inventing a floating tie Beam / Third Box for the existing box in box construction leading to a new box in box in Box / Box 3 / Box cube for serial or parallel kinematic or hybrid kinematic architecture machine tools as claimed in claims 1, 2 & 3, having the floating tie beams (4) being in the desired extreme positions, the said floating tie beams (4) be locked so that, during the general operation of the machine, the floating tie beams (4) do not move towards the area of operation of the machine and hence, a suitable locking mechanism being in place.
5. A novel Cartesian grid structure for large format moving bridge machining centers by inventing a floating tie Beam / Third Box for the existing box in box construction leading to a new box in box in Box / Box 3 / Box cube for serial or parallel kinematic or hybrid kinematic architecture machine tools as claimed in claims 1, 2. 3 & 4, during the normal operation of the machine each of the floating tie beams (4) being positioned on the extreme ends of the Y axis (4) enabling to achieve no hindrance to operation of the machine and when the job / work piece (14) being loaded / unloaded on the bed of the X axis (1) along with the Z axis (3), one floating tie beam (4) being taken to one of the extreme ends of the Y Axis (2) and the remaining floating tie beam (4) also being taken to the other extreme end of the Y Axis (2), so that the same can be brought closer to the X Axis (1) so that, the crane (15) being able enter between both the Y Axis (2) and load /

unload the job / work piece (14) and hence the advantages of a monocock structure when the floating tie beams (4) being locked in their respective positions and the flexibility of sliding the off as and when needed.