FORM 2
THE PATENT ACT 1970 (39 of 1970)
&
The Patents Rules, 2003 COMPLETE SPECIFICATION
(See Section 10, and rule 13)
1. TITLE OF INVENTION
CNC VERTICAL TURNING MACHINE-Model: PTB 150
2. APPLICANT(S)
a) Name : PREMIER LIMITED
b) Nationality : INDIAN Company
c) Address : 58, NARIMAN BHAVAN,
NARIMAN POINT, MUMBAI-400 021, MAHARASHTRA, INDIA
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed : -

FIELD OF THE INVENTION
The invention relates in general to turning machines, and in particular to a CNC vertical turning machine suitable for producing medium sized machined products of diameter up to 1500 mm on a mass scale at a high rate of production.
BACKGROUND AND PRIOR ART
In recent years there has emerged a need to machine work pieces of medium size on a large scale with the usual requirements of a high accuracy of finish and maximum rate of production. Such requirement exists, for example, in the field of production of valves, casings, cylinder blocks, pistons, piston rings and bearings for internal combustion engines of locomotives.
There has thus emerged a requirement for a machine which is capable of machining work pieces rapidly and accurately to have the desired non-uniform profiles. Such a machine must have the capability of altering the tool position a number of times within a revolution, if it is to machine oval and elliptical profiles and must be able to do this at high speeds.
Turning machines are well known in the art. They are deployed for machining desired profiles and shapes from a piece of metal stock as the stock is turned or rotated at a relatively high speed. A typical turning machine comprises a rigid base, a chuck assembly for holding a piece of stock material in place relative to the machine, a motor and transmission for rotating the chuck assembly with the stock material at a desired speed and a tooling assembly for machining the stock material as it is turned. The tooling assembly generally includes a turret or ram with automatic tool changer unit, which holds a variety of cutting tools and allows for any a number of these cutting tools to be interchanged for use in machining a part. Typically, turning machines also include a controller which controls the radial and axial positioning of a cutting tool to produce the desired shape and finish.

Various types of turning machines are known in the prior art. One type of turning machine is known as the vertical turning machine because the stock to be machined rotates around a vertical axis as it is machined.
Turning machines are generally adapted to produce a wide variety of parts, and thus are capable of operating at a wide variety of speeds and of holding a large number of different cutting tools which can be interchanged during the machining process to produce the particular part desired. While conventional turning machines are well adapted to perform a wide variety of machining operations, there are unfortunately several drawbacks with existing turning machines. For example, conventional turning machines require a large quantity of cooling lubricant to be applied to the cutting edge of the cutting tool to remove heat generated during the cutting operation. Otherwise, the heat generated from the cutting operation may cause the turned part, such as an aluminum part, to melt, and may otherwise damage the finish of the machined part. Unfortunately, coolant is expensive, leaves a residue on the finished part and on the turning machine, and may cause environmental and health problems.
Additionally, turning machine of the prior art being designed to be highly versatile, they often require a transmission to adjust the turning speed of the stock material. Also a turret or ATC to house a large number of cutting tools and various other assemblies to improve the flexibility and versatility of the machine are necessary.
As a result of the complexity of such turning machines, they also are difficult and expensive to maintain and tend to wear very quickly. One major area of wear in conventional turning machines is the drive arrangement. The drive arrangement typically includes a motor, a transmission and a belt to transmit rotational power to the spindle and chuck assembly. In such an arrangement, the drive components transmit power through a number of drive belts and pulleys which are maintained under high tension so that the drive power from the motor can be efficiently transferred to the spindle and chuck.

Unfortunately during transmission, the brake tends to wear significantly as do the bearings of the various rotational items, such as the pulleys, because of the significant amount of belt tension and resultant stresses on the various components. Another drawback of the known turning machines is that the rotational speed of the stock material, and thus the speed at which the material can be machined, is limited to speeds below which these machines tend to experience chatter and vibration which can harm the machine or damage the part being machined.
Additionally, as most of the typical turning machines are designed for small and medium sized components, this cannot fulfill all the requirements of the modern industry.
It would be desirable to provide a turning machine which could turn the parts of comparatively large size and machine them at a higher frequency and thus allow the part to be machined faster, as well as to provide a machine that require significant cooling lubricants or exhibit significant vibration or chatter during the cutting process.
OBJECTS OF THE INVENTION
The primary object of the invention is to overcome the drawbacks of the prior art. Another object of the invention is to provide a CNC vertical turning machine which has minimum number of rotating parts.
Yet another object of the invention is to provide a vertical turning machine which has table base, column and structural member manufactured with SG iron and having adequate mass and structural rigidity to provide significant dampening force to the machine to reduce harmonics and vibrations (chatter).
A further object of the invention is to provide a vertical turning machine which has rapid X and Z axis movements.

A still further object of the invention is to provide a vertical turning machine which has a tool holder located in a taper cartridge and clamped within the ram by radial clamps.
Another object of the invention is to provide a vertical turning machine which has a cast structure cross rail with high precision preloaded ball screw assembly for high positioning accuracy and repeatability.
SUMMARY OF THE INVENTION
The invention discloses a CNC vertical turning machine suitable for producing medium sized machined products of diameter up to 1500 mm on a mass scale at a high rate of production. It primarily comprises of a table base supporting a table with four jaws, or alternatively a chuck body unit, a column connected to the table base with the help of a structural member (joining piece), an Automatic Tool Changer or ATC, a ram head with live spindle and a moving cross rail with slide. It has also an electric control panel, a swiveling control pendant, a chip conveyor and a chip trolley. Elevating gearbox assembly with the elevating motor is mounted on top of the column. The tool holder is located and clamped within the ram by radial clamps. It is located in a taper cartridge because the tool holder traverses in the ram housing. Linear bearings are fixed in the ram housing in which the ram slides.
A CNC controller, which may be a conventional CNC controller, is used in the machine. The chip conveyor is placed inside a pit below the ground level.
The table base, column and structural member are manufactured with SG iron. They have adequate mass and structural rigidity to provide significant dampening force to the machine to reduce harmonics and vibrations (chatter) generated by the cutting action of the machine and rotation of the drive motor.

The machine is made with minimum rotating parts. It has high speed rapid travel for both X axis and Z axis movements.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The nature and scope of the present invention will be better understood from the accompanying drawings, which are by way of illustration of a preferred embodiment and not by way of any sort of limitation. In the accompanying drawings:-
Fig 1(a) illustrates the front view of the vertical turning machine according to the present invention.
Fig 1(b) is the side view of the machine.
Fig 1(c) illustrates the plan of the machine.
Fig 2 schematically illustrates the table drive assembly of the machine.
Fig 3 schematically illustrates the elevating gear box as per the present invention.
Fig 4 schematically illustrates the x axis kinematics of the vertical turning machine as per the present invention.
Fig.5 schematically illustrates the z axis kinematics of the machine.
Fig.6 schematically illustrates the live spindle drive of the machine.
Fig. 7 schematically illustrates the ATC drive of the machine as per the present invention.

DETAILED DESCRIPTION OF THE INVENTION
Having described the main features of the invention above, a more detailed and non-limiting description of a preferred embodiment will be given in the following paragraphs, with reference to the accompanying drawings.
The vertical turning machine according to the present invention is ideally suited for the following machining operations, but can also undertake a host of other machining operations not listed here for the sake of brevity.
Boring
Turning
Facing
Taper Turning
The preferred embodiment of the present invention is shown in figures 1(a), 1(b) and 1(c). As is described below, the vertical turning machine is designed and adapted as a machine particularly suited for the manufacture of medium sized components with the usual requirements of high accuracy of finish and maximum speed of production. As such, the vertical turning machine is designed with a minimum number of moving parts and assemblies and is adapted to turn the work piece to be machined at a high speed with minimal vibration and chatter. The vertical turning machine comprises of a table base (4) to which an AC table drive motor (5) and a spindle assembly is mounted, as best seen in figure 2. The table base (4) and column (2) are connected with the help of a structural member (joining piece) and are manufactured with SG iron having adequate mass and structural rigidity to provide significant dampening force to the machine to reduce harmonics and vibrations (i.e. chatter) generated by the cutting action of the machine and rotation of the drive motor.

Column.(2) is a cast structure. A cross rail elevating motor (13) with its gearbox (15, 16), best shown in figure 3, is mounted on top of the column. It is mounted at the rear end, on top of the table base.
Cross rail slide (12) is a cast structure which is either fixed on the column flange or moves with the ram (1). The cross rail contains a high precision preloaded ball screw assembly which carries the cross rail (12) for high positioning accuracy and repeatability. Cross rail slide (12) moves in X direction as determined by the guide ways provided on the cross rail. Cross rail slide guide ways are lubricated by automatic lubrication system (42) for smooth movement along X-axis.
The ram head (1) with its tool holder (21) is mounted on the cross-rail. The head consists of a totally enclosed square ram which slides in the ram housing. The tool holder (21) is located and clamped in the tool adaptor which is fitted at the bottom of the ram. Balancing of the ram head is done with the help of a hydraulic cylinder.
A table (3) with four jaws is used for holding the work piece. Machining of the work piece is performed by rotating the table. Mechanically operated jaws on the table are used to locate and clamp the components.
Hydraulically operated chuck body unit is an alternative option, where the chuck body itself provides rigid support to the work piece. Machining of the work piece is performed by rotating the chuck body. Hydraulically operated jaws on the chuck are used to locate and clamp the components. Hydraulic clamping arrangement is provided in the chuck body with the help of a hydraulic cylinder mounted underside of the table base (4). It has provision for high and low pressure central clamping. Auxiliary slides provide fine adjustments for proper clamping of the job. An encoder assembly is attached to the clamping cylinder which provides feedback of the table speed in RPM.

An automatic lubrication system (42) is used to provide lubrication in a pressurized state to all sliding elements of the machine like ball screws, ball screw support bearing, guide ways of slides etc. Re-circulation type oil lubrication is provided for the spindle assembly.
Chip conveyor (33) is a robust conveyor which is adapted to carry maximum chips. Slat type chip conveyor (33) is used for carrying chips from the machine interior to a chip trolley (37). The chip conveyor is placed in the pit below the ground and the trolley (37) is placed on ground. Slat type chip conveyors are very suitable to carry curly chips. A coolant tank of 500 liter capacity is provided.
A control panel (36) is mounted on the left side of the machine. A swiveling control pendant (39) is positioned in front of the machine at the side of the operator. It is designed on the basis of ergonomics.
Reference is now made to figure 2, which schematically illustrates the table assembly of the present invention. The machine table (3) is mounted on the front side of the table base (4) and is located on a pre-loaded bearing assembly consisting of a ball thrust bearing for thrust (axial) loads and a central precision taper roller bearing for radial loads.
The table is driven by AC table drive motor (5) through pulleys (8, 9), flat belt (10) and a two-stage gear box (7) which is hydraulically operated. Table drive motor (5) is mounted vertically on a mounting plate and can be adjusted for tensioning the flat belt (10). The table speed is infinitely variable between the minimum and maximum values within the individual ranges of the hydraulically operated two-stage gear box (7) in the table base. Lubricant for the table bearing lubrication power pack is also contained in the table base. The table can machine the part on either side of the table center.

Fig. 3 schematically illustrates the elevating gear box of the present invention. Cross rail may be provided in two types, either fixed or moving. The elevating gear box of this invention is provided with a moving cross rail. An elevating motor (13) with worm and worm-wheel (15,16) with a high reduction ratio is provided to impart movement to the cross rail.
Fig 4 illustrates the kinematics for movement along X axis of the present invention. An AC servomotor (23) is coupled through gear transmission (24, 25) to precision ball screw (22), which results in high speed rapid travel along X axis.
Fig 5 illustrates the kinematics for Z axis movement of the present invention, wherein an AC servomotor (27) is coupled through gear transmission (28, 29) to precision ball screw (26), which results in high speed rapid travel along Z axis.
Fig. 6 schematically illustrates the live spindle drive of the machine of the present invention. The main spindle (20) is driven by spindle motor (18) through a 2-speed gear box (19) which provides speed in two different ranges. The machine of the present invention with the live spindle offers drilling, tapping, reaming and milling operations in addition to turning, boring, facing and taper turning.
Fig. 7 schematically illustrates the ATC Drive of the present invention. The machine is equipped with an Automatic Tool Changer (ATC) (30), which can be a conventional one, for complete automatic tool changing. The ATC is driven through gear and pinion arrangement (33, 34) by drive motor (32) connected to gearbox (35). Said ATC (30) for the ram consists of horizontal disc type tool magazine plate (31) with tool pockets for boring, turning, milling and drilling tools and special adapters for mounting rotary tools. Said magazine plate (31) is mounted on a separate column located on the right side of the machine.
The ATC unit carries 12/20 tools. It is mounted either on the cross rail end or on the floor. The ATC is of disc type and is located on a pair of taper roller bearings. The disc

is a cast structure and has slots for tools to be stored. The disc is locked at each tool position by means of a hydraulic cylinder-actuated plunger pin, which enters a ground bush for precisely locating the position of the tool. The ATC disc has two tennons per tool pocket for lightly locking the tool holders.
The tool holder (21), shown in figure 1 (b), is located and clamped within the ram by radial clamps. The tool holder is located in a taper cartridge because the tool holder traverses in the ram housing. Linear bearings are fixed in the ram housing in which the ram slides.
A CNC controller, which may be a conventional CNC controller, is used in the machine. The machine has a metal cladding (41).
The present invention has been described with reference to some drawings and a preferred embodiment purely for the sake of understanding and not by way of any limitation and the present invention includes all legitimate developments within the scope of what has been described herein before and claimed in the appended claims.

WE CLAIM:
1. A CNC vertical turning machine comprising of a table base (4) having a table
(3) with four jaws, alternatively a chuck body unit, a column (2) connected to
said table base (4) with the help of a structural member (joining piece), an
Automatic Tool Changer or ATC (30), a ram head (1) with live spindle, cross
rail slide (12), electric control panel (36), a swiveling control pendant (39), a
chip conveyor (33), a chip trolley (37), elevating gearbox (15, 16), tool holder
(21), said chip conveyor (33) being placed inside the pit below the ground level
and a cladding (41),
wherein said table base (4), column (2) and structural member are manufactured with SG iron having adequate mass and structural rigidity to provide significant dampening force to the machine to reduce harmonics and vibrations (chatter) generated by the cutting action of the machine and rotation of the drive motor .
2. The turning machine as claimed in claim 1, wherein said chuck body unit has hydraulically operated jaws which are operated with the help of a hydraulic cylinder mounted underside of the said table base (4).
3. The turning machine as claimed in claim 1, wherein said table base (4) has said machine table (3) mounted on its front side and located on a pre-loaded bearing assembly consisting of a ball thrust bearing for thrust (axial load) and a central precision taper roller bearing for radial loads.
4. The turning machine as claimed in claim 1, wherein said table (3) is driven by AC table drive motor (5) through pulleys (8, 9), flat belt (10) and a two-stage gear box (7).
5. The turning machine as claimed in claims 1 and 4, wherein said motor (5) is mounted vertically on a mounting plate and is adjusted for tensioning said flat belt (10).

6. The turning machine as claimed in claims 1 and 4, wherein speed of said table (3) is infinitely variable between the minimum and maximum values within the individual ranges of the hydraulically operated two-stage gear box (7) in the table base.
7. The turning machine as claimed in claim 1, wherein said cross rail (12) is a cast structure which contains high precision preloaded ball screw assembly for high positioning accuracy and repeatability.
8. The turning machine as claimed in claim 1, wherein AC servomotor (23) is coupled through gear and pinion transmission (24, 25) to precision ball screw (22) which provides high speed rapid travel for X axis.
9. The turning machine as claimed in claim 1, wherein AC servomotor (27) is coupled through gear and pinion transmission (28, 29) to precision ball screw (26) which provides high speed rapid travel for Z axis.
10. The turning machine as claimed in claim 1, wherein said live spindle drive contains main spindle (20) which is driven by spindle motor (18) through 2-speed gear box (19) providing motion in two different speed ranges.
11. The turning machine as claimed in claim 1, wherein said tool holder (21) is located in a taper cartridge and clamped within said ram (1) by radial clamps and travels within said ram housing.