Field of the invention The present invention relates to a pipe clamping and cutting apparatus for CNC machine. More particularly, the present invention relates to clamping and cutting apparatus that provides precise cutting through minimizing the ovality though the pipe have small dimension. Background and prior art of the invention

Computer Numeric Control (CNC) is the automation of machine tools that are operated by precisely programmed commands encoded on a storage medium (computer command module, usually located on the device) as opposed to controlled manually by hand wheels or levers, or mechanically automated by cams alone.

CNC or Computer Numerical Control has been used in machining operations for decades to automate machining operations that previously were performed by a manual operator. Such operations include moving a tool or workpiece in relation to each other in three dimensional space in order to perform an operation on the workpiece. CNC programming consists of generating computer commands that are passed to a machine tool that has a CNC control. The commands instruct the control on what tool paths the machine tool should take and sets various machining conditions such as the feed, or speed the tool cuts into the workpiece, and spindle speed, or the speed with which the tool rotates when cutting the workpiece.

The primary goals of any CNC turning operation are quality and speed. Five main factors influence the quality and speed of a turning operation: 1) Rigidity of cutting tool, 2) Sharpness of cutting tool, 3) Hardness of work-piece, 4) Speed of work-piece rotation ("spindle speed"), and 5) Amount of material removed ("feed rate"). The precision for cutting tube in CNC machine with low dimension faces problems of shape change (i.e. ovality).

There are several known ways to form and cut a pipe. A pipe may be formed by spirally or helically winding a continuous strip of metal and joining adjacent edges of the wound strip to form a spiral lockseam in the pipe. In some pipe forming and cutting machines, the spirally formed pipe is cut by moving a knife outside the pipe into an overlapping position with a knife inside the pipe. Other types of spiral pipe forming and cutting machines use multiple knives or rotate the knives around the pipe to cut the pipe into sections. One type of pipe cutting machine uses a single rotatable knife in a fixed position with respect to the pipe. In this field there are known several methods of clamping a generally cylindrical shank into the clamping portion of a cutting tool. One method makes use of a conical collet and a sleeve, thread rotated around the collet to reduce its diameter, thereby clamping the shank of the cutting insert. This clamping method has a disadvantage in that after the cutting insert is replaced, it is difficult to position the new cutting insert in the exact original orientation of the old cutting insert. Further, the collet use in pipe cutting machine whether or not used in combination with an insert member, has been that when the collet jaws are forced radially inward the internal work engaging surfaces of the individual jaw members tend to pivot about the solid body portion. This results in the work piece being gripped primarily by the front portion of the collet thereby reducing the contact between the work engaging surfaces and the work piece. This causes a reduction in the work gripping force as well as excessive wear of the forward portions of the internal jaw surfaces.

Generally, when it is desired to cut pipes of intermediate size each pipe is mounted in and gripped by a chuck of a lathe and rotated while a non-rotating tool fit is moved laterally into the rotating chucked pipe. The cutting is accomplished in several successive turns of the pipe as the tool bit is moved gradually into the rotating pipe. The lathe requires a heavy bed which is fixed and contained in a permanent location such as a shop. Additionally the tool bit requires rigid holding supports which are movable. Heavy duty power equipment is also required to operate- the various components of the pipe cutting facilities.

To overcome aforesaid difficulties, various kinds of pipe cutting device have been developed. Such device is disclosed in Patent Application No. US 5033344 that provides pipe cutting machine including a cutter blade, a reward and forward clamper and pneumatic cylinder. The drawbacks of this known drive are this machine can not cut the pipe with shorter diameter. Further, the clamping apparatus to clamp the pipe is not proper. In conclusion, a pipe or tube cutting apparatus is necessary that can improve productivity and sever a continuously formed pipe rapidly and efficiently in low dimension pipe also. There has been long need for a highly effective automatic pipe cutting and clamping machine that continuously and automatically severs continuous tubing into predetermined lengths with a clean cut and with minimum ovality. Object of the invention

The main object of the present invention is to provide a pipe clamping and cutting apparatus for Computer Numerical Control (CNC) machine.

Another object of this invention is to provide apparatus with clamping and cutting assemblies that co-ordinately disposed with each other for precise cutting in small dimension pipe.

A further object of the present invention is to provide clamping and cutting assemblies that co-ordinately work in sequential pattern to clamp and cut pipe respectively to diminish ovality issue.

Another object of the present invention is to provide apparatus that can easily established on CNC machine for fast, versatile and accurate cutting that easily fragment the long pipe with small dimension to a predetermined short dimensions without major alteration in CNC machine.

The object of the present invention is to provide an improved feed collet and also to provide a feed collet having means for preventing the collet from scratching or otherwise damaging the pipe or work when it is intermittently fed through the feed tube and the collet. Summary of the Invention

The present invention relates to a pipe clamping and cutting apparatus for CNC machine. The present invention discloses apparatus that compatible to established on X and Y axis of CNC machine. The present invention discloses stationery and movable clamping means, cutting means and driving means arranged in specific manner that cut precisely cut pipe with low dimension. The clamping and cutting of the present apparatus on pipe with sequential pattern provides precise cut on final work piece with respect to ovality and surface texture. The present apparatus mainly includes X and Y apparatus of CNC machine and pair of clamping jig that accompanied with collate, spring punch, pneumatic apparatus, cutter and servo motor. Brief Description of the Drawings

Fig.l shows perspective arrangement of the present system.

Fig. 2 shows perspective view of the collet.

Fig. 3 describes the side view juncture of X-Y system.

Detailed description of the Invention Before explaining the present invention in detail, it is to be understood that the invention is not limited in its application to the details of the construction and arrangement of parts illustrated in the accompany drawings. The invention is capable of other embodiments, as depicted in figure as described above and of being practiced or carried out in a variety of ways. It is to be understood that the phraseology and terminology employed herein is for the purpose of description and not of limitation.

Fig.l shows a pipe clamping and cutting apparatus for CNC machine. As shown in Fig.l, CNC machine for cutting pipe comprises a driving means, a movable clamping means and a stationary clamping means for pipes on Y axis and a driving means and a rotating means for pipes on X axis.

The Y apparatus driving means is mounted upon an elongated bed frame (9), resembling in some ways an ordinary a lathe bed. A trolley (11) is mounted on the bed (9) and governed by a drive screw (10) and a servo motor (8) in order to control precise horizontal retrogressive movement on Y axis as per the command received from a control panel (7). The control panel (7) is mounted on panel board (20) to control the pipe cutting apparatus.

The movable clamping means of Y axis comprises a clamping plate (1) which is rigidly secured on upper side of the trolley (11) (As shown in enlarged portion A). The clamping plate (1) further consists of a pneumatic cylinder (2), a pressure plate (19) (shown in fig.3), a spring punch (5), a clamping jig (6) and a collet (3). The pneumatic cylinder (2) disposed parallel with the wall of the clamping plate (1) to provide compression on the pressure plate (19) adjacent to pneumatic cylinder (2). The spring punch (5) is securely between pressure plate (19) and clamping jig (6) to provide reciprocating linear motion to pressure plate (19). The clamping jig (6) is horizontally slotted structure to accompany collet (3) in side the slots. The clamping jig (6) is provided with at least one collet (3) which arranged to be compressed to hold pipe (4) firmly while Y apparatus trolley (11) moves in horizontal direction.

The stationary clamping means of Y apparatus comprises a supporting plate (26), a pneumatic cylinder (2'), a pressure plate (19'), a spring punch (5'), a pair of clamping jig (6 and 6') and at least one collet (3') (As shown in enlarged portion B). The pneumatic cylinder (2') disposed parallel with the wall of the supporting plate (26) to provide compression on the pressure plate (19') adjacent to pneumatic cylinder (2'). The spring punch (5') is secured between the pressure plate (19') and the clamping jig (6') to provide reciprocating linear motion to pressure plate (19') as and where pressure generated or released from pneumatic cylinder (2'). The pair of clamping jig, (6 & 6') are disposed in close proximity and separated by slit (25) (as shown in Fig. 3). The pair of clamping jig (6 & 6') are horizontally slotted structure to accompany collet (3') in side the slots. The clamping jig (6') is provided with at least one collet (3') which arranged to be compressed to hold at least one feed stock of pipe (4).

The X axis driving means is mounted upon an elongated a bed frame (9') which resembles in some ways to an ordinary a lathe bed. A trolley (14) is mounted on the bed (9') and governed by a drive screw (16) and a servo motor (15) in order to control precise horizontal retrogressive movement on X axis as per the command received from a control panel (7).

The cutting motor (18) of the rotating means of X axis is established in upward position on the trolley (14) to provide rotating force to a cutter blade (12) of cutting means. A flexible belt (17) is looped between axially aligned shafts of the motor (18) and a mandrel (13), to provide passive rotation in mandrel (13) during working of the motor (18). The flexible belt (17) is securely mounted between parallel positioned cutter shaft and the motor (18) where the flexible belt (17) is looped to rotate both shafts in unified direction with each other when the motor (18) is in operational mode. The flexible belt (17) is coupled to the mandrel (13) for rotating the motor (18) and thus the cutter blade (12) movable to work onto or machine.

Fig. 2 describes perspective view of a collet used in the present invention. The collet (3, 3' and 3") is a tubular structure made up of metal with a cylindrical sleeve (21) having a prongs (22) at distil end and a flange (23) at the proximal end. The sleeve is gradually reduced in prongs (22) through a slits (24) which discrete the prongs (22) from each other. The flange (23) disposed in the position to hold collet (3, 3' and 3") in clamping jig (6' and 6") (shown in Fig. 3). The aperture of the flange (23) at proximal end is identical with the openings of prongs (22) at the distil end during the fasten mode of collet. The aperture of proximal end provides rigid support to the work piece which restore dimension by the way of restoring original shape of the pipe. The present collet (3, 3' and 3") can have prongs (22) in the range of 2-4 as per the requirement of work piece and rigidity of the metal. The collet (3, 3' and 3") used in the present invention have some degree of flexibility at the proximal end to clamp the pipes (4) in rigid manner that nullify the chances of the ovality in final work piece.

Fig. 3 shows juncture of X and Y axis of the present apparatus in top view position. The apparatus comprises cutter wheel (12) (as shown in Fig. 1) and pair of clamping jig (6' & 6") to clamp the feed stock of pipes (4) received from movable clamping means. The pair of clamping jig (6' & 6") accommodate collet (3' & 3") through their respective ends. The collet (3' & 3") are fastened through pressurizing spring punches (5 & 5') via pneumatic cylinder (2'). The cutter apparatus clamping jigs (6' & 6") share single pneumatic cylinder (2') with fasten and unfasten pressurizing spring punches (5 & 5') as and when commands received from the control panel (7).

The cutting apparatus described in Fig. 3 have closely arranged pair of clamping jig (6' and 6") that accommodate collet (3' & 3") contrived to closely confine distil end of collet (3' & 3") with each other. The cutter slit (25) is provided to cut the feed stock of pipe (4) through moving cutter wheel (12) as and when command received form the control penal (7). The cutting apparatus cuts the feed stock of pipe (4) in coordination of X apparatus cutter assembly and Y apparatus feed stock assembly. The cutting apparatus cuts the feed stock of pipe (4) as and when the command received form the control panel (7). The control panel (7) is used to set operational panel parameters, so as to carry out a completely automatic cutting operation without manually processing and to provide multiple functions, such as precisely and speedily cutting, lowering the manufacture cost, and enhancing the yield.

The method of pipe cutting comprises the following steps, at lease one pipe (4) is loaded into an open positioned collet (3) a feed stock in clamping jig (6) of movable clamping plate (1); the collet (3) of movable clamping means is clamped by pressurizing pressure plate (19) through pneumatic cylinder (2) to hold feed stock firmly in manner that provides outwardly extended portion of pipe (4) at proximal end of clamping jig (6); the trolley (11) is moved in forward direction till the proximity between the clamping jigs (6 and 6') of stationery and movable clamping means are attained in positioned that outward extended portion of pipe is fasten in collet (3') accommodated in clamping jig (6') of stationery clamping means at proximal end of Y axis;

the movement of the trolley (11) is retrogressed by releasing the collet (3) of moving clamping jig (6) through reciprocating motion of pressure plate (19) through pneumatic cylinder (2), till the distil end of Y axis apparatus attained by the trolley (11);

the collet (3) is clamped by compressing pressure plate (19) through pneumatic cylinder (2) to hold the pipe (4) firmly in clamping jig (6) of movable clamping means; f) the pair of collet (3' & 3") of stationery clamping jig (6' and 6") is released by reciprocating motion of pressure plate (19) through pneumatic cylinder (2') to release collet (3' & 3") previously fasten at step (c);

g) the trolley (11) is moved in a predetermined one unit length forward, through driving means of Y axis, that drive extended portion of pipe (4) disposed at stationery clamping jig (6' and 6") to one unit in forward direction;

h) the pair of collet (3' and 3") is clamped by compressing pressure plate (19) through pneumatic cylinder (2') to hold pipe (4) firmly in the pair of clamping jig (6' and 6") of stationary clamping means;

i) the trolley (14) is moved in forward direction through driving means of X axis that drive cutter blade (12) towards proximal end of the X axis to perpendicular impale cutter blade (12) on the pipe

(4) clamped in stationery clamping means through slit (25); j) the pair of collet (3' & 3") of stationery clamping jig (6' & 6") is released by reciprocating motion of pressure plate (19) through pneumatic cylinder (2') to release collet (3' & 3") previously fasten at step (h);

k) the trolley (14) is retrogressed by driving means of X axis that remove the cutter blade (12) from slit (25);

1) the finished work piece of the pipe (4) is discharged continuously from proximal end of the cutting jig (6') as the trolley (11) gradually moves in forward direction till the proximal end of Y axis;

m) the movement of trolley (11) is retrogressed, by releasing collet

(3) of moving clamping jig (6) by reciprocating motion of the pressure plate (19) through pneumatic cylinder (2), till the distil end of X axis. The present invention provides following advantages:

1. The present invention provides apparatus which cut long pipes in predetermined small fragments with precise size.

2. The present invention provides apparatus that co-ordinately works with clamping and cutting tools for accurate cutting in low dimension pipe.

3. The present invention provides collet with specific prong arrangement that provides adaptable holding on work piece which facilitate cutting with lower ovality and lesser damage on the wok piece.

4. The present invention provides fast and accurate cutting solution for pipe or tube that has low thickness (i.e. 5 to 11 mm).

5. The present invention provides fast and accurate cutting solution for pipe or tube that has length upto 5mm.

6. The present invention provides versatile apparatus that can be used for different soft metals (i.e. silver, tin, zinc, aluminum, thorium, copper, brass and bronze) with accurate result.

7. The present invention provides apparatus that can easily established on CNC machine for fast, versatile and accurate cutting that easily fragment the long pipe with small dimension to a predetermined short dimensions without major alteration in CNC machine. While various embodiments of the present invention have been described in detail, it is apparent that modification and adaptation of those embodiments will occur to those skilled in the art. It is expressly understood, however, that such modifications and adaptations are within the spirit and scope of the present invention as set forth in the following claims.

Reference numerals use in invention:

1 movable clamping plate

2 stationary clamping plate

3 collet of movable clamping plate

3' and 3" collet of stationary clamping plate

4 feed stock of pipes

5 spring punch of movable clamping plate

5' spring punch of stationary clamping plate

6 clamping jig of movable clamping plate

6' stationary clamping plate

7 control panel

8 servo motor of y apparatus

9 bed frame of Y axis

9' bed frame of X axis

10 drive screw

11 trolley of Y axis

12 cutter blade

13 mandrel

14 trolley of X axis

15 servo motor of X axis

16 drive screw

17 flexible belt

18 motor for cutting blade pressure plate of movable clamping plate ' pressure plate of stationary clamping plate panel board

sleeves

prongs

flange

slits

cutter slit

supporting plate