FORM 2
THE PATENT ACT 197 0 (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-105
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 CNC controlled machines and in particular to a CNC vertical turning machine for machining work piece of diameter up to 1050 mm with high-speed rotation.
BACKGROUND AND PRIOR ART
In recent years there has emerged a need to machine work pieces of medium size which should be produced in large quantities. The usual requirements are high accuracy of finish and maximum speed 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.
Turning machines are well known in the art. Turning machines are used to machine desired metal pieces and shapes from a piece of stock as the stock is turned or rotated at a relatively high speed. A typical turning machine includes 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 holding 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 while machining a part. Typically, turning machines also include a controller which controls the radial and axial positioning of a cutting tool to produce a part of the desired shape.
One type of turning machine is known as a vertical turning machine as the stock to be machined rotates around a vertical axis as it is machined. Various other types of turning machines are also known.

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. But coolant is expensive, leaves a residue on the finished part and on the turning machine, and may cause environmental and health problems.
Additionally, when a turning machine is designed to be highly versatile, it often requires a transmission to adjust the turning speed of the stock material, 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.
As a result of the complexity of various turning machines, they also are difficult and expensive to maintain and tend to wear very quickly. One 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 typically transfer power through a number of drive belts and pulleys which are maintained under significant tension so that the motive power is transferred efficiently to the spindle and chuck.
However, all moving parts and frictional parts like the brake tend to wear significantly because of the high belt tension and resultant stresses on the various components. Another drawback of many 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, they cannot meet all the demands of modern industries.
It would be desirable to provide a turning machine which could turn the parts of comparatively large size and machine them at a higher rotational speed and thus allow the part to be machined faster. Also, the coolant requirement of the machine must be low and it should not exhibit significant vibration or chatter during the cutting process.
In the prior art, there are numerous types of turning machines meant for various types of applications. But still there is a dearth of really fast yielding but accurate machines that are chatter free and consume less lubricant.
Therefore, there exists a requirement in the industry for a machine which is capable of machining work pieces rapidly and accurately to generate the desired nonuniform and complicated profiles. It will be appreciated that such a machine must have the capability of altering the tool position a number of times even within a revolution, if it is to machine oval and elliptical profiles and must be able to do this at high speeds. Additionally, it must be free of vibration and chatter and demand lesser quantity of coolants.
The present invention discloses a new and unique dedicated CNC vertical turning machine which can machine the medium sized components with greater efficiency. Additionally it can machine the part at either side of the table center. It is adapted for machining work pieces of diameter up to 1050 mm with high speed rotation, greater

stability and less chatter. Its coolant demand is also less. It therefore overcomes the drawbacks of the prior art.
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 vertical turning machine having a table base with sufficient mass and area to provide a dampening force that reduces vibrations and harmonics generated by the machine.
Yet another object of the invention is to provide a vertical turning machine wherein the spindle assembly rotates about a vertical axis at such a rate that chip fragments aviate off a work piece which is being machined.
A further object of the invention is to provide a vertical turning machine wherein the heat generated by the tooling process is removed by the chips.
Another object of the invention is to provide a vertical turning machine wherein the speed of the table is infinitely variable between the minimum and maximum values within the individual ranges of the hydraulically operated two-stage gear box in the table base.
A still further object of the invention is to provide a vertical turning machine wherein an AC servomotor is coupled through gear transmission to precision ball screw which provides high speed rapid travel for X axis.
Yet another object of the invention is to provide a vertical turning machine wherein another AC servomotor is coupled through gear transmission to a precision ball screw which provides high speed rapid travel for Z axis.

SUMMARY OF THE INVENTION
The invention discloses a CNC vertical turning machine comprising of a table base having four jaws or alternatively a chuck body unit, a column connected to the table base with the help of a structural member, an ATC, a live spindle drive, electric control panel, a chip conveyor, a chip trolley, elevating gearbox, cross rail and tool holder. A coolant tank and a chip conveyor are placed inside a pit below the ground level.
The table base has sufficient mass and area to provide a dampening force that reduces vibrations and harmonics generated by the machine. The spindle assembly rotates about a vertical axis at such a rate that chip fragments aviate off a work piece being machined, so that heat generated by the tooling process is removed by the chips.
The chuck body unit has hydraulically operated jaws that are operated with the help of a hydraulic cylinder mounted underside of the table base.
The table base has a machine table mounted on its front side. It is located on a preloaded bearing assembly consisting of a ball thrust bearing for thrust (axial load) and a central precision taper roller bearing for radial loads.
The table is driven by an AC table drive motor through two pulleys, a flat belt and a two- stage gear box. The motor is mounted vertically on a mounting plate and is adjusted for tensioning of the flat belt.
The speed of the table is infinitely variable between the minimum and maximum values within the individual ranges of the hydraulically operated two-stage gear box in the table base.

The cross rail is a cast structure which contains high precision preloaded ball screw assembly for high positioning accuracy and repeatability.
An AC servomotor is coupled through gear transmission to precision ball screw which provides high speed rapid travel for X axis.
Another AC servomotor is coupled through gear transmission to a precision ball screw which provides high speed rapid travel for Z axis.
The live spindle drive contains main spindle driven by a spindle motor through gear transmission. A 2-speed gear box provides motion in two different speed ranges.
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: -
Figl(a) illustrates the front view of the vertical turning machine according to the present invention.
Fig 1(b) illustrates the side view of the machine.
Fig 1(c) illustrates the plan view.
Fig 2 schematically illustrates the table drive assembly.
Fig 3 schematically illustrates elevating gear box.
Fig 4 schematically illustrates the x-axis kinematics of the machine.

Fig.5 schematically illustrates the z-axis kinematics.
Fig.6 schematically illustrates the live spindle drive and
Fig.7 schematically illustrates the ATC of the vertical turning machine according to 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 preferred embodiment of the present invention is shown in figures 1(a), 1(b) and 1(c). The CNC vertical turning machine according to the present invention is adapted for manufacture of medium sized parts with the requirements of high accuracy of finish with maximum rate of production. The vertical turning machine is designed with a minimal number of moving parts and assemblies and is suitable for turning the work piece to be machined at a high speed with minimal vibration and chatter. The machine is suitable for the following machining procedures:
Boring Turning Facing
Taper turning . Drilling Tapping Reaming and Milling

As shown in figures 1(a), 1 (b) and 1(c), the vertical turning machine comprises of a table base (4) to which an AC table motor (5, best seen in figure 2) and a spindle assembly is mounted. The motor (5) is adapted to run at very high speeds and is connected to the spindle through a direct drive arrangement. The direct drive arrangement comprises of a single flat belt (10) and a table drive gear box (7), also best seen in figure 2, to efficiently transfer rotational power from the motor to the spindle with minimal wear on the rotating parts.
Table base (4) is constructed with sufficient mass and area to provide a dampening force that reduces vibrations and harmonics generated by the machine while it is in turning operation.
The motor (18) and gear drive assembly of the spindle assembly are adapted to rotate the assembly about a vertical axis at such a rate that chip fragments aviate off a work piece being machined, so that heat generated by the tooling process is removed by the chips which have absorbed the heat.
Column (2) is connected to said table base (4) with the help of a structural member (joining piece). Both said column and table base are fabricated with adequate mass and structural rigidity to provide significant dampening 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. Additionally, the machine is designed throughout to minimize the number of moving parts, and thus to reduce the vibration characteristics of the machine. These factors together eliminate the vibration and chatter.
A preloaded anti-friction bearing system for high axial and radial rigidity and accuracy is used for the table gear box (7), seen in figure 2. It consists of a combination of a thrust bearing to take the axial force and a precision angular contact ball bearing to take the radial forces.

The machine table (3) is made of SG iron and is mounted on a bearing system. It has four jaws, or alternatively, a chuck body unit (1) which is hydraulically operated to provide 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 to be machined (jobs). 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 facility for high- and low-pressure central clamping. Auxiliary slides provide fine adjustments for the job clamping. An encoder assembly is attached to the clamping cylinder to obtain feedback of the actual table RPM.
Alternatively; a table with four jaws can be used for holding the work piece. Machining of the work piece is performed by rotation of the table. Mechanically operated jaws on the table are used to locate and clamp the components.
As shown in figure 1(a), the control panel (39) is mounted on the left side of the machine. A swivel-type pendant box, which is designed and positioned on the basis of ergonomics, is mounted in front of the machine at the side of the operator.
As best seen in figure 1(b), elevating gear box (14) is provided with moving a cross rail (11). As in figure 3, elevating motor (13) with worm and worm wheel (15,16) with high reduction ratio is provided to give movement to said cross rail. The machine has a cladding (41).
As best seen in figure 1(c), automatic lubrication system (42) provides lubrication in pressurized state to all sliding elements like ball screws, ball screw support bearing, guide ways of slides etc. Recirculation type of oil lubrication is provided for spindle assembly. It has a lubricant cooling unit (40). Tool magazine plate (31) of the automatic tool changer ATC (30) is mounted on a separate column located on the right side of the machine. Coolant tank (38), voltage stabilizer (43) and transformer (44) are positioned peripherally to the turning machine.

A chip conveyor (36) of robust construction is provided to carry maximum chips. It is a slat type chip conveyor which carries the chips from machine interior to a chip trolley (37). The chip conveyor (36) is placed inside a pit below ground level and trolley (37) is placed on ground. Slat type chip conveyor is very suitable to carry curly chips. A coolant tank (38), best seen in figure 1(c), is of 500 liter capacity and is also placed inside the pit below the ground level.
Figure 2 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 load) and a central precision taper roller bearing for radial loads.
Table (3) is driven by AC table motor (5) through pulleys (8, 9), flat belt (10) and a two stage gear box (7). 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 2 stage gear box (7) in the table base. Lubricant power pack (6) for table bearing lubrication shown in figure 1(c) is also contained in the table base.
Figure 3 is a schematic representation of the elevating gear box of the present invention. A cross rail provided can either be fixed or moving, as in this invention. The cross rail elevating motor with the gearbox is mounted on top of the column (2). It is mounted at the rear end on top of the table base.
Cross rail (11) is a cast structure which is either fixed on the column flange or moves with ram. The cross rail is provided with high precision preloaded ball screw assembly which carries the cross rail slide for high positioning accuracy and repeatability. The cross rail slide moves in X direction guided by the guide ways on the cross rail. Cross rail slide guide ways are lubricated by a centralized lubrication system for smooth movement along the X-axis.

The ram head with the tool holder location is mounted on the cross-rail. The head consists of a totally enclosed square ram which slides in the ram housing. The tool holder is located and clamped in the tool adaptor which is fitted at the bottom of the ram. Balancing of the ram head is by means of a hydraulic cylinder.
Fig 4 represents the kinematics for X axis movement of the present invention, wherein an 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.
Fig 5 illustrates the kinematics for Z axis of the present invention, wherein an 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.
Fig. 6 schematically represents the live spindle drive of the present invention. The main spindle (20) is driven by spindle motor (18) through gear transmission. 2-speed gear box (19) provides motion in two different speed ranges. The machine with live spindle offers drilling, tapping, reaming and milling operations in addition to turning, boring, facing and taper turning.
Fig. 7 schematically illustrates the Automatic Tool Changer (ATC) of the present invention, which can be a conventional one. The machine is equipped with an ATC (30) for complete automatic operation of tool changing. The ATC is driven through gear and pinion arrangement (33, 34) by AC drive motor (32). Automatic tool changer ATC (30) for ram consists of horizontal disc type magazine plate (31) with tool pockets for boring, turning, milling and drilling tools and special adapters for mounting rotary tools. Tool magazine plate (31) is mounted on separate column located on the right side of the machine.
The ATC unit carries 12/20 tools. It is mounted on the cross rail end or on the floor. The ATC is of disc type and 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.
A turret with turret slide and a swiveling part can be an alternative to a ram head and ATC. Turret slide moves in '7', direction (Up/down). Indexing of tool of turret is done hydraulically.
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 chuck body unit (1), or alternatively four jaws, 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 live spindle drive, electric control panel (39), a chip conveyor (36), a chip trolley (37), elevating gearbox (14), cross rail (11), tool holder (21), said chip conveyor (36) and a coolant tank (38) being placed inside the pit below the ground level and a cladding (41), wherein said base (4) has sufficient mass and area to provide a dampening force that reduces vibrations and harmonics generated by the machine and said spindle assembly rotates about a vertical axis at such a rate that chip fragments aviate off a work piece being machined, so that heat generated by the tooling process is removed by the chips.
2. The turning machine as claimed in claim 1, wherein said chuck body unit (1) has hydraulically operated jaws being 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 machine table (3) mounted on its front side which is 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 gearbox (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 (11) 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) driven by spindle motor (18) through gear transmission and 2-speed gear box (19) provides motion in two different speed
ranges.