WO2012120526A1

WO2012120526A1 - A cold rolling system

Info

Publication number: WO2012120526A1
Application number: PCT/IN2011/000454
Authority: WO
Inventors: Sanjay Harishandra WAGHULADE; Mahesh MISTRI
Original assignee: Innoventive Industries Ltd
Priority date: 2011-03-09
Filing date: 2011-07-07
Publication date: 2012-09-13

Abstract

The present invention relates to a cold rolling system. The die and roller assembly (5) of the system comprises of at least two profiled rolls (die) mounted in a horizontal plane. The profiled rolls are mounted on a vertical shaft (51 ) wherein the said assembly is slidably fitted on the guide rods (6) so that it could reciprocate on the said guide rods (6). The said assembly is coupled to the first end of connecting rod (4) that is operated by the crank gear (20) of the driving system (306). The synergistic combination of disposition of the profiled rolls in horizontal plane, use of the gear for speed reduction as well as providing cam effect and use of drive shaft as guide bar results in obviating problems associated with the work head and unbalanced forces, failure of the mandrel, reduced stroke frequency of the work head and undesirable marks on the finished tube surface.

Description

Field of Invention

The present invention relates to a cold rolling system, in particular the invention relates to a cold rolling system with die / profiled rolls that are disposed in horizontal plane.

Background of the Invention

Conventional cold rolling system, popularly known as pilger mill primarily comprises of cam shaped profiled rolls. As depicted in Figure 1, the profiled rolls are disposed in vertical plane. The profiles of the rolls are shaped so that on rotation they bite into the tube to force it down onto the mandrel wherein the mandrel is disposed inside the tube. The mandrel is then moved back to drag the tube against the rolls and smooth its outside diameter, the cycle is repeated.

The cold pilgering process relies on four main actions: The tube moves forward and it rotates while the profiled rolls (also known as ring dies) move back and forth and rotate. As shown in Figure 1 , a connecting rod drives the system on which the said rolls are mounted (known as mill saddle or work head) back and forth. This action causes the rolls to rotate. This action is similar to a crankshaft driving a piston in an automobile engine. Pinions mounted on each roll shaft engage two racks that are fixed to the machine housing. This arrangement uses the mill saddle's oscillating motion to generate the rolls oscillating rotary motion.

It is challenging to cold roll tubes of substantially smaller diameter (of the order of 4 mm to 8 mm Outside Diameter) on pilger mills. One of the reasons being mandrel that fits on the inside diameter of the tube being cold rolled is used to rotate as well as provide linear motion to the tube. The smaller diameter of the mandrel over the large length may cause failure during the operation of rotation and linear motion. Further vibration and impact due to combination of rotation of the rolls as well as reciprocating motion of the work head on which the rolls are mounted result in forces leading to undesirable marks / impressions on the tube surface. Attempts are made with regard to pilger mill developments. The relevant prior art is as follows:

CA1068136 discloses a system for incrementally and continuously feeding tubes between dies during a prescribed angle of rotation of a crank assembly in a cold pilger mill. As a main motor drives the crank assembly, a servo-motor, receiving a signal from a digital control unit, which receives a signal from a pulsating encoder associated with the main drive, operates to incrementally advance a carriage and shell a controlled predetermined distance between the dies. A reversal of the servo-motor returns the carriage to the initial position in preparation to advance another shell.

CA1194068 discloses a bearing construction for a crankshaft of a cold Pilger rolling mill for the rolling of tubes wherein the connecting rod is attached to the mill and in which case friction is created between an abrasion bushing made from surface-hardened steel and a bearing box made of high-load or strength synthetic material. For the lubrication of the friction surfaces, the cooling fluid employed for rolling is used. For better removal of heat, the abrasion bushings are provided with means such as cooling fins or similar surfaceenlarging profiles and/or materials with high thermal conductivity.

United States Patent 4386512 discloses a compensating counterweight system used in a cold pilger step-by-step type seamless tube rolling mill reciprocated by a crank assembly. The crank assembly includes first and second compensating mass devices which are arranged to rotate coaxially on a single crank shaft in opposite directions relative to each other. The two mass devices are kinetically connected through a bevel gear drive set which causes the second compensating mass device to rotate in an opposite direction to the first compensating mass device

CN 1351909 discloses the rolling curve of the drive pinions of ring rollers are adapted to the neutral zone in decreasing caliber of the ring rollers of a cold pilger rolling mill, by using circular pinions, which are positioned eccentrically on and fastened to the roller shaft. Sinusoidal toothed racks are used to drive pinions and ring rollers. If circular eccentric pinions are used, which mesh with sinusoidal racks, for parameters can be adapted to actual roller dimensions:- roller diameter, pinion reference circle, eccentricity, angular position of eccentricity relative to entrance dead center of roller stand.

United States Patent 4577483 discloses a spur gear assembly for axially mounting and supporting an end of a feed screw for each carriage and is driven from the main drive, since these feed screws of each carriage are arranged coaxially along a line parallel to a passline of the pilger mill. This spur gear allows relative rotation of the feed screws in this gear assembly mounting and a similar mounting is provided for the other screws of the pair of screws for each carriage. A first gear unit connected to the main drive causes a reciprocation of the stand along with the two feed carriages, and a second gear unit including a shaft clutch assembly is selectively brought into engagement and disengagement with the spur gear assemblies and the first gear unit to impart rotation to the screws to separately and independently advance and return the feed carriages to their starting position while one of the feed carriages continues to advance the shell through the mill. United States Patent 6205833 discloses a cold pilger rolling tool for producing internally ribbed tubes uses a cold pilger step rolling process in a rolling stand that is movable back and forth in a direction of rolling and has rolls of a tapered design. The rolls of the stand roll along a material with an alternating direction of rotation. The tool includes a cold pilger rolling mandrel which tapers. The tool further comprises an extension plug mounted coaxially and rotatably at a free end of the cold pilger rolling mandrel and in which a negative of the helical internal ribbing which is to be produced is machined

United States Patent 6257040 discloses a method for controlling a hydraulic rotary and feed drive for a cold pilger rolling mill for producing rolling stock, the cold pilger mill having a rolling stand that moves back and forth in the rolling direction by a crank drive so that rolls of the roll stand, which are of tapering design, roll over the rolling stock with an alternating sense of rotation. The roll stand intermittently releases the rolling stock so that the rolling stock may be rotated and fed by the hydraulic rotary and feed drive to a new position as a function of the position of the crankshaft of the roll stand. The rotation and feeding of the tube are performed by hydraulic motors controlled by pressure medium and assigned to the drive members acting on the tube. The pressure medium feed of each hydraulic motor is controlled by a proportional valve which is opened for a time interval proportional to a path required for the drive member moved by this hydraulic motor

DE2051045 discloses a billet rotation device for a pilger cold-rolling mill for tube mfr., where the main drive of the reciprocating mill continuously drives a gear train which includes a worm where axial motion is superimposed on its rotation using cam-discs and followers for retarding or accelerating the rotational motion. The novelty is that at least two cam-discs are mounted on a common shaft and the contact lines with the followers are displaced 180 degrees from cam-disc to cam- disc, but the sum of the radii to the contact lines is constant for ail angular positions. Three cam-discs are pref. mounted on one shaft, the central disc being wider than the other two, and three cam followers are pref. used.

United States Patent 3705655 discloses a device for feeding oblong workpieces, particularly for a cold pilger machine comprises first and second endless conveyors having opposed reaches extending substantially parallel and between which a workpiece is adapted to be fed by engagement with the conveyor. The conveyors are supported in a housing which is rotatably mounted in order to impart a rotation to the workpiece in addition to its transverse feeding movement. The apparatus includes an input or drive shaft connected through a first cam controlled gearing for controlling the rotation of the housing and connected through a second cam controlled gearing for controlling the advancement movement of the conveyors. The second cam controlled gearing includes a belt drive which provides for a variation of operation and a drive through planetary gearing and rotary gear members for effecting the drive of the conveyor elements.

Japanese Patent JP10128413 discloses a system to efficiently operate the whole manufacturing process of steel tubes while making the best use of the feature of Pilger mill rolling. The solution disclosed comprises of three mandrels 2 are respectively arranged in the insides of three tube stocks 1 which are arranged in parallel, three pairs of grooved rolls 5 are coaxially connected, each pair of grooved rolls is arranged on the peripheral surface of each tube stock so that the inside face of the groove 6 of the roll is brought into contact with the outer peripheral surface of each tube stock and three tubes are simultaneously rolled. The mandrel 2 has a rolling part 3 whose diameter is gradually decreased in the rolling direction and the distance between the groove bottom and the center axis 7 of the roll of the grooved roll 5 is continuously changed in accordance with the change of the diameter of the rolling part. The groove shape and dimensions of the three sets of the grooved rolls 5 and mandrels 2 are set so that the distributions of their working ratios are mutually substantially same and, by the one set of combination, the rolled tube having the diameter dimension different from that of the rolled tubes which are rolled with the other sets of combinations is obtained.

Japanese Patent JP2008073753 discloses a method for continuously rolling a tube stock in the rolling in a cold Pilger mill. The solution is in the form of a the method for rolling the tube stock in the cold Pilger mill, a preceding tube stock to be rolled is rolled by the length of a succeeding tube stock to be rolled, a feed stand is retracted, the succeeding tube stock is inserted, and the feed stand is advanced toward a roll die before starting the automatic rolling. When the feed stand hits a rear end of the succeeding tube stock, a pressure switch installed on the feed stand is not operated and the feed stand is continuously advanced. When a fore end of the succeeding tube stock hits a rear end of the preceding tube stock, the pressure switch is operated to detect that the fore end of the succeeding tube stock hits the rear end of the preceding tube stock and the feed stand is stopped.

United States Patent 5916320 discloses a method and apparatus for manufacturing tubes, preferably tubes composed of high-tensile steels or special alloys, using the cold pilger rolling method with two rolling stands which can be moved backward and forward, at least in opposite directions at times and in the rolling direction by means of crank drives. The rolling stands have rollers which are calibrated in a tapering manner and which, driven by toothed racks via cogs, roll over the material to be rolled, with an alternating rotation direction. The majority of the forming work takes place on the first rolling stand and a relatively small portion of the forming work takes place on the second rolling stand and additional smoothing work is carried out. Reduction rolling takes place in both rolling stands via a mandrel which is matched to the roller caliber, and the backward and forward movements of the two rolling stands are matched to one another in such a manner that the angular offset between the crank drives is chosen such that the forming zone of the first stand does not occur at the same time as the forming zone of the second stand

RU2210444 discloses a processes for cold pilger rolling, namely of superthin-wall tubes and small-diameter rods. SUBSTANCE: method is realized in apparatus having rolls mounted in mill for cold pilger rolling having rolling stand performing reciprocation motion. Rolls are narrowed and sized by their perimeter. By means of said rolls rolled product is turned at least in one of two dead points of rolling stand and it is transported forward. In order to rotate rolled product and to transport it forward, transporting apparatus is mounted at outlet side directly after rolling stand for embracing along perimeter article rolled in pilger rolling mill. In order to control transportation speed of transporting apparatus arranged at outlet side, at first transportation speed of rolled product at outlet of rolling stand is measured when transporting apparatus is open at outlet side. Measurement result is used for controlling speed of drive mechanism of transporting apparatus in such a way that to increase speed of transporting apparatus arranged at outlet side by 3 - 10% relative to transportation speed of drive mechanism for feeding at inlet side before closing transporting apparatus relative to rolled product. EFFECT: possibility for rolling superthin-wall tubes, especially small tubes or small-diameter rods without hazard of occurring jamming or laps. 6 cl, 1 dwg, 1 ex European Patent Application EP0277086 discloses invention in order to simplify, and to render easier, and to avoid manipulating difficulties of small-diameter pipes, which have to be separated and singled in the processing at a separating distance and which have to be transported after the processing either within a factory or to different manufacturing or treatment stations or between factories, and in particular of pipes with the bulges present or to be applied at their ends, such as pipe-connection nuts, protective caps, it is disclosed that the pipes are separated continuously with a fixed distance in between the pipes and are disposed at such a distance in a direction parallel to their axis, and are further separated on a moving suppor. then each pipe is provided, during the continuous motion in a direction perpendicular to the pipe axis, with a neighboring or with a more remote pipe in a parallel axial position by way of hinged disengageable connection members which, in each case, correspond to the fixed distance and wherein the pipe mat of pipes and hinged connections members is continuously withdrawn and possibly wound to a bundle

United States Patent 3661005 discloses method for producing seamless tubes of small diameter. The starting tube is subjected to at least one initial cold drawing over an interior tool, decreasing the diameter and the wall thickness of the tube so that the^nteriortube surface is brought into complete contact with the interior tool. The tube is then subjected to stretch reducing and to final cold drawing over an interior tool.

Japanese Patent JP06154815 discloses a system to manufacture a small- diameter thick-walled electric resistance welded steel tube with high thickness rate t/D to the outside diameter with the small number of roll stands by re-suppressing the deterioration of shape due to the angularity of the inside surface. In the method for manufacturing the small-diameter thick-walled electric resistance welded steel tube by cold reducing rolling an electric resistance welded steel tube which is obtained by welding an open pipe which is obtained by forming a steel strip, a reducing stage where cold reducing rolling is executed with three-roll reducers of two or more stands and diameter finishing stage with two-roll reducers of one or more stands are combined. And, the circumferential speed of roll at a 1st stand in the reducing stage with the three- roll reducer is set higher than the tube feeding speed, the circumferential speed of roll on and after the 2nd stand is set lower than the tube feeding speed and the circumferential speed of roll at the final stand in the diameter finishing stage with the two-roll reducer is set higher than the tube feeding speed. In this way, reducing rolling at high outside diameter draft is enabled.

Japanese Patent JP09176732 discloses a method for producing a steel tube in which, to tensile- compressive stress working to the axial direction at the time of big earthquake local buckling is less prone to occur and brittle breaking is less prone to occur even if it is the large sized thin one, furthermore small in sound anisotropy and low in a yield ratio. The solution is in the form of a steel contg., by weight, 0.05 to 0.25% C and 0.5 to 2.0% Mn, is subjected to rolling at the unrecrystallization temp, or below to ≥60%, is furthermore applied with rolling reduction at ≥40% at the unrecrystallization temp, to 850°C, is thereafter subjected to hot rolling at the Ar3 temp, or above decided by the chemical components in the steel and is subsequently cooled at a cooling rate of >2°C/sec from the temp, range of (the Ar3+40) to (the Ar3-80)°C decided by the chemical components in the steel, and this steel is subjected to cold forming into a steel tube.

Review of the prior art reveals that the pilger mill / cold rolling system for manufacture of substantially smaller diameter tubes is not disclosed. The pilger mill / cold rolling system of the prior art further suffer from following drawbacks:

Limitation on number of strokes (work head reciprocation frequency) per unit time due to bulky work head

s Undesirable vibrations and generation of forces due to reciprocating movement of the bulky work head as well as rotation of the rolls in vertical plane causing marks on the surface of the tube

s Need of separate speed reduction means in terms of gear box and belt drive resulting in lack of positive drive

fluctuating vertical (though substantially small) instantaneous displacement of the rolls in vertical plane causing vibrations leading to generation of marks on the tube surface

Failure of bearings due to unbalanced forces on the work head due to the difference in height of the point of application of force at the work head and connecting rod end at the flywheel

•s Possible unbalanced forces due to disposition of the rolls in vertical plane Need of flywheel

^■s Failure of mandrel while cold rolling substantially smaller diameter tubes

The necessity is constantly felt to provide improved cold rolling system / pilger mill obviating problems associated with the work head and unbalanced forces, failure of the mandrel, reduced stroke frequency of the work head and undesirable marks on the finished tube surface.

Summary of the Invention

The main object of the invention is to provide a cold rolling system/ pilger mill. Further object of the invention is to provide profiled rolls / ring dies in horizontal plane. Another object of the invention is to integrate the aspects of speed reduction, providing reciprocating motion with the aid of cam and connecting rod assembly and transferring the power in perpendicular direction (with respect to the axis of cam and connecting rod assembly) for driving the feed box in a single unit. Another object of the invention is to integrate function of the drive shaft, tube guide and pusher.

Yet another object of the invention is to provide guides/ restricting means to prohibit undesirable displacement of the profiled rolls / dies in horizontal plane away from each other.

Yet another object of the invention is to substantially reduce weight of the work head. Yet another object of the invention is to substantially reduce power transmission stages.

Thus in accordance with the invention the cold rolling system comprises of at least two profiled rolls / dies mounted adjacent to each other in horizontal plane on a work head / die and roll assembly wherein the said assembly is reciprocated by a cam and connecting rod means.

Description of the Invention

Features and advantages of the invention will become apparent in the following detailed description and preferred embodiments.

Figure 1 Conventional cold pilger mill (prior art) (Sheet 1)

Figure 2 Schematic of the cold rolling system (Sheet 2)

Figure 3 Schematic of the cold rolling system (Sheet 3)

Figure 4 Schematic of the cold rolling system (Sheet 4)

Figure 5 Schematic of the die roll assembly (Sheet 5)

Figure 5a Schematic of stopper assembly (Sheet 6)

Figure 5b Schematic of connector assembly (Sheet 7)

Figure 6 Schematic of the main housing (Sheet 8)

Figure 7 Schematic of the driving system (Sheet 9)

Figure 7a Schematic of motor disposition (Sheet 10)

Figure 8 Schematic of the feeding bed (Sheet 11)

Figure 9 Schematic of the feed and turn gear box (Sheet 12)

Figure 9a Schematic of the variant of the feed and turn gear box (Sheet 13)

Figure 2 depicts elevation and plan of the cold rolling system of the present invention. Figure 3 and Figure 4 as well illustrate the details of the system from different angles for better comprehension. As illustrated in Figure 3, the system comprises of

die roller assembly 304 (illustrated in Figure 5)

main housing 305 (illustrated in Figure 6)

driving system 306 (illustrated in Figure 7)

^ feeding bed 303 (illustrated in Figure 8),

feed and turn gear box 302 (illustrated in Figure 9)

main motor (prime mover) 307, trolley motor 308, base structure 301. Figure 2 depicts front and top view of the cold rolling system. As illustrated, the die roller assembly 5 comprises of die / profiled rolls mounted in a horizontal plane. This is elaborated in the Enlarged view A as well as top view. In the enlarged view A, first profiled roll 50 is seen (in elevation) mounted on a vertical shaft 51. It can be seen with reference to the top view that the other roll is provided adjacent to the said first roll (in enlarged elevation view it is not seen as it is hiding behind the first roll 51). The two profiled rolls / dies are disposed in horizontal plane. The said assembly 5 is adapted to be slidably fitted on the guide rods 6 (With reference to Figure 6, it is 604a and 604b) so that it could reciprocate on the said guide rods 6. The assembly 5 is operably coupled to the first end of connecting rod 4. Other end of the said connecting rod 4 is operably connected to the gear 20 (offset disposition in the proximity of the gear teeth) that is meshed with another gear 21 of smaller diameter. It is to be noted that the said gear 20 functions to reduce speed as well as provides cam effect (due to the offset connection / disposition of the connecting rod end) to reciprocate the said connection rod 4. This results in making the gear box compact. The driving system comprises of motor 1 that drives the said gear 21. The gear box 2 of the said driving system further comprise of bevel gear assembly that is mounted on the shaft of the gear 20. The power is transmitted from the said gear 20 in perpendicular direction through this bevel gear assembly to drive shaft cum guide bar 2. It is to be noted that the drive shaft functions as guide bar as well for the tube guide 8 and the tube pusher 9. The said bar 12 is further adapted to be connected and coupled to the feed & turn gear box 10 that is used to provide feed as well as rotation to the tube with the aid of feed screw 7 and mandrel chuck 11.

Figure 5 illustrates further details of the said die and roll assembly 5 described above. It comprises of die / profiled rolls 503a and 503b mounted in a horizontal plane. The said two profiled rolls / dies are disposed in horizontal plane as shown in the Figure. Each of the said rolls / dies are removably mounted on one of the ends of die shaft 508a and 508b respectively. The said shafts are further fitted with the spherical roller bearings that are mounted in bearing housings 504a and 504b. The other end of the said die shafts is fitted with roller gears wherein one of the shafts (508a) is fitted with the first roller gear 506a that is operably engaged with the second roller gear 506b mounted on the shaft 508b. The said shaft 508b is further fitted with a pinion 507 adjacent to the said roller gear 506a. The said pinion 507 operably engages with the rack (not shown) disposed on the main housing. The guide bush housings 501a and 501b are provided adjacent to each of the said bearing housing 504a and 504b. Each of the said housings comprises of bushings 509a and 509b so as to slidably fit on the guide rods 6 (refer Figure 2) so as to reciprocate on the said rods. The taper plate assembly 502 is provided between one of the guide bush housings 501a and the said bearing housing 504a. It comprises of at least two taper plates disposed with the tapered portions of each of the plate in contact with each other. This is used to adjust distance between the said die rolls. Connector 505 is fitted on one of the vertical surface of the said bearing housing 504a and 504b. It is used to connect the crank connecting rod (not shown).

One of the embodiments of the said die and roll assembly is depicted in Figure 5a. it comprises of first and second stopper plates 520 and 521. The said first stopper plate 520 is disposed vertically between the said taper plate assembly 502 and the said guide bush housing 501a as illustrated in the Figure 5a. The said second stopper plate 521 is disposed vertically between the said guide bush housing 501b and the said bearing housing 504b. In yet another variant of this embodiment the stopper plate is selected from metal, alloy, rubber based material, vibration absorbing material etc.

Another embodiment of the said connector 505 is depicted in the Figure 5b. The said connector comprises of an eccentric pin 550. The said pin comprises of substantially flat top cylindrical portion 561 provided with a provision for removably receiving screw / bolt 552, below the said cylindrical portion there is provided another cylindrical portion 560 of comparatively lower diameter than the said top portion. This portion is press fitted in the first pin holding member 553 that is in the form of a substantially thick plate provided with a hole of corresponding diameter of the portion 560 so as to receive the said portion 560. The said member 553 is adapted to receive the said screw/ bolt 552 that passes through the said top portion 561. The said member is secured to the bracket 551 that is in the form of a plate. Below the said cylindrical portion 560, the said pin is provided with an offset cylindrical portion 555 wherein center of this offset cylindrical portion 555 and the centre of the said flat top cylindrical portion 561 are distanced apart. The end portion 556 of the pin is of smaller diameter than the said offset portion. The centre of the end portion and the centre of the said flat top cylindrical portion coincide. The said end portion is adapted to be pressfitted in the second pin holding member 554. End of the connecting rod 704 (Figure 7) is adapted to be fitted in the said offset cylindrical portion 555. This arrangement enables to adjust the distance between the crank gear and the die and roller assembly. This is possible by rotation of the said pin so as to face / orient the said offset portion 555 towards the said bracket in which case the distance from the crank gear is maximum. If the said offset portion is oriented towards the crank gear side (as shown in the Figure 5b) the distance is minimum. This arrangement provides flexibility in selecting stroke length of the die and roller assembly.

Figure 6 illustrates main housing 601. It comprises of vertically disposed preferably metal plates 607, 608, 609 and 610 as indicated in the Figure. In one of the embodiments the said metal plates could be any other load bearing structural component that a skill person in this art would contemplate. A rack mounting plate 602 is disposed substantially horizontally towards one of the ends of the said housing 601. The driving system (not shown) is disposed at the other end. The said rack mounting plate is secured on the metal plates (607 and 610). Further rack 603 is mounted on this plate in a manner that it is operably meshed with the said pinion 507 of the said die and roller assembly (Figure 5). The guide bars 604a and 604b (they are as well mentioned as 6 in the Figure 2) are mounted longitudinally adapted to be operably engaged with the said bushings 509a and 509b of the die and roller assembly. Oil pump 605 is operably driven by the said driving system (not shown). Lubrication line 606 from the said oil pump 605 is routed to the said guide bars 604a and 604b, rack and other components. The lubrication oil is further provided to the nozzle 610 that is disposed in the vicinity of the said die and roller assembly (not shown in the Figure 6) so as to splash the lubrication oil on the said profiled rolls 503a and 503b.

The driving system is illustrated in Figure 7. It comprises of input shaft 708. One of the ends of the said shaft 708 is mounted with a pulley 710 for operably connecting with a prime mover (not shown) such as motor. In one of the embodiments the said pulley could be replaced by gear system (not shown). The said shaft 708 is rotatably secured in the bearings (not shown) mounted in the driving system housing 701. The other end of the said shaft 708 is mounted with pinion gear 702 that is meshed with the drive / crank gear 703 as illustrated in the Figure 7. The said crank gear 703 is mounted on crank gear shaft 706 that is rotatably secured in the said driving system housing 701. One of the ends of the connecting rod 704 is operably mounted on the said crank gear 703 in the proximity of the gear teeth, the other end of the said connecting rod 704 operably connected to the said connector 505 (refer Figure 5) of the said die and roll assembly 5. The said pinion gear 702 and the crank gear 703 are disposed substantially in one horizontal plane on the surface of the housing 701 as illustrate in the Figure 7. The first bevel gear 707 is mounted on the said crank gear shaft 706 inside the housing wherein the second bevel gear 710 is operably meshed with the said first bevel gear 707. The said second bevel gear 710 is mounted on the output shaft 705 wherein the said crank gear shaft 706 and the said output shaft 705 are substantially perpendicular to each other. The said housing is optionally secured on the base plate 709. Figure 7a depicts one of the preferred embodiments of the mounting of the motor 752 that is operably coupled to the pulley arrangement. The said motor 752 is disposed on one of the vertical members of the said main housing. The vertical disposition of the motor with the output shaft accessible at the top of the said main housing facilitates drive to the said pinion gear 702 from top of the drive unit. The input shaft 751 is operably connected at one end to the pulley 753 and other end to the said pinion gear 702. Figure 8 illustrates feeding bed. The front portion of the said feeding bed is connected to the main housing 601 and rear portion is connected to the feed and turn gear box. The said feeding bed comprises of connecting shaft 801 that is operably coupled to the said output shaft 705 of the said driving system. The said connecting shaft 801 is coupled operably to the drive shaft cum guide bar 806 that is rotatably supported in the mounting brackets 802a and 802b disposed at front and rear portion of the feeding bed. Feed screw 803 is supported in the said mounting brackets 802a and 802b. Guide plates 804a and 804b as well as feeding pusher trolley 805 are operably engaged in the said feed screw and are supported by the said drive shaft cum guide bar 806 as illustrated in the Figure 8. The function of the said feed screw 803 (that is powered / rotated by the feed and turn gear box) is to enable pipe blank feed in linear direction as well as to provide partial rotation intermittently in tandem with the reciprocating motion of the said die and roller assembly. Further provision (not shown) is made in terms of motor to operate the said feed screw so as to enable quick return the said pusher trolley 805 at the rear end.

Figure 9 illustrates feed and turn gear box. It is used to intermittently rotate mandrel that is inserted in the pipe blank thereby partially rotating the pipe blank as well as feeding the same in linear direction in tandem with the reciprocafing movement of the said die and roller assembly. The feed and turn gear box comprises of input shaft 901 that is mounted with gears operably engaged with turning mechanism 907 wherein the said mechanism and feeding gear 906 are mounted on the feeding shaft 902. The said input shaft is coupled with the said drive shaft cum guide bar 806 of the feeding bed and the said feed shaft is coupled with the said feed screw 803 of the feed bed. The said feeding gear 906 is further operably meshed with the turning gear 905 that is mounted on the turning spindle 903. The said input shaft 901 , feeding shaft 902 and the turning spindle 903 are rotatably mounted in the housing 904 as illustrated in the Figure 9. The intermittent rotation of the mandrel rod and the intermittent rotating and feeding of the pipe blank are completed by the rotating iShaft and the feed screw. The blank is rolled back and forth through driving the rotating shaft and main machine body. Another embodiment of the said gear box is depicted in Figure 9a used for providing multiple feeds. In addition to the components described in the Figure 9, it comprises of a shifter mechanism provided with a gear shifter 920 that is mounted on a shaft 921 such that the said shifter slides over the said shaft. The shifter is operably in connection with the shifting gear assembly 922 that is mounted on the splined shaft 923 as depicted in the Figure 9a. A person skilled in art can contemplate that the shifter mechanism enables engagement of various gears. This allows combination of meshing of gears with diverse diameters resulting in combination of speeds. This enables providing multiple feeds.

The aforementioned systems of the present invention work in tandem with each other. Following are the details of the kinematics / force and, thereby power transmission of the prime mover to various components of the system of the present invention:

the power from the prime mover 307 is transmitted to the pulley 710 (or pulley 953);

V this results in rotation of the pinion 702 and in turn crank gear 703;

since the crank gear diameter is larger than that of the pinion 702, there is speed reduction and torque enhancement;

the rotation of the crank gear results in operation of the connecting rod 704 which is coupled with the said connector 505 of the die and roller assembly; this results in providing linear reciprocating motion to the said roller and die assembly which is secured (so as to restrict movement in translational direction) in the said guide bars (604a and 604b);

the reciprocating motion of the said die and roller assembly results in rotation of the pinion 507 of the said die and roller assembly that is engaged with the rack 603;

the rotation of the said pinion 507 enables mutual rotation of the said roller gears 506a and 506b;

V such mutual rotation of the said roller gears 506a and 506b results in mutual rolling of the said two profiled rollers 503a and 503b;

the raw pipe that is to be cold rolled is fed in terms of intermittent rotation and linear feed with the help of feed screw that is operated with the aid of the said feed and turn gear box wherein input power for the same is derived from the drive system itself.

In one of the embodiments the intermittent rotation able is in the range of 55 to 60° and the linear feed is in the rage of 2mm to 5 mm. However, these parameters can be adjusted / set in accordance with the diameter of the pipe blank and velocity with which the said die and roller assembly reciprocates.

In one of the embodiments lubrication oil is stored in the said main housing wherein the housing itself acts as oil pan.

In one of the embodiments the prime mover is a DC motor provided with variable speed drive. Thus it is evident that the synergistic combination of disposition of the profiled rolls in horizontal plane, use of the gear for speed reduction as well as providing cam effect and use of drive shaft as guide bar results in obviating problems associated with the work head and unbalanced forces, failure of the mandrel, reduced stroke frequency of the work head and undesirable marks on the finished tube surface.

Claims

1. A cold rolling system comprising

die roller assembly unit (304) (illustrated in Figure 5),

main housing (305) (Figure 6),

S driving system (306) (Figure 7),

✓ feeding bed (303) (Figure 8),

feed and turn gear box (302) (Figure 9),

main motor (307), trolley motor (308), base structure (301 ) wherein

the die and roller assembly (Figure 2) (5) comprises of at least two profiled rolls (die) mounted in a horizontal plane, the said profiled rolls are mounted on a vertical shaft (51) wherein the said assembly (5) is adapted to be slidably fitted on the guide rods 6 (With reference to Figure 6, it is 604a and 604b) so that it could reciprocate on the said guide rods (6), the said guide rods are mounted in the main housing;

the said assembly (5) is coupled to the first end of connecting rod (4) wherein other end of the said connecting rod is coupled to crank gear (20) that is meshed with pinion gear (21 );

the said pinion gear (21 ) is driven by the driving system comprising motor (1 ), gear box (2) wherein the gear box comprises of bevel gear assembly that is mounted on the shaft of the gear (20) wherein power is transmitted from the said gear (20) in perpendicular direction through this bevel gear assembly to drive shaft cum guide bar (12) that functions as guide bar as well for the tube guide (8) and the tube pusher (9) of the feeding bed;

the said bar (12) is coupled to the feed & turn gear box (10) that is used to provide feed as well as rotation to the tube with the aid of feed screw (7) and mandrel chuck (1 1 ).

2. A cold rolling system as claimed in claim 1 wherein the said die and roller assembly (5) comprises of (Figure 5)

profiled rolls (503a) and (503b) mounted in a horizontal plane wherein each of the said rolls is removably mounted on one of the ends of die shaft (508a) and (508b), the said shafts are further fitted with the spherical roller bearings that are mounted in bearing housings (504a) and (504b), the other end of the said die shafts is fitted with roller gears wherein one of the shafts (508b) is fitted with the first roller gear (506b) that is operably engaged with the second roller gear (506a) mounted on the shaft (508a), the said shaft (508b) is further fitted with a pinion (507) adjacent to the said roller gear (506a);

the said pinion (507) operably engages with the rack that is disposed on the main housing;

the guide bush housings (501a) and (501b) are provided adjacent to each of the said bearing housing (504a) and (504b) wherein each of the said housings comprises of bushings (509a) and (509b) so as to slidably fit on the guide rods (6) (refer Figure 2) so as to reciprocate on the said rods; the taper plate assembly (502) is provided between one of the guide bush housings (501a) and the said bearing housing (504a), the said taper assembly comprises of at least two taper plates disposed with the tapered portions of each of the plate in contact with each other;

connector (505) is fitted on one of the vertical surface of the said bearing housing (504a) and (504b), it is used to connect the connecting rod.

3. A cold rolling system as claimed in claim 1 wherein the main housing (Figure 6) comprises of

vertically disposed four members preferably metal plates (607), (608), (609) and (610) to form a housing (601);

a rack mounting plate (602) disposed in substantially horizontal plane towards one of the ends of the said housing (601) wherein the said rack mounting plate is secured on the metal plates (607 and 610);

the rack (603) that is mounted on the said rack mounting plate as to be meshed with the said pinion (507) of the said die and roller assembly;

guide bars (604a, 604b) mounted longitudinally in the said housing (601) are operably engaged with the said bushings (509a and 509b) of the die and roller assembly, the said guide bars are provided with oil galleries for lubrication purpose;

oil pump (605) that is driven by the said driving system wherein lubrication line (606) from the said oil pump (605) is routed to the said guide bars (604a and 604b) and rack, lubrication oil is further provided to the nozzle (610) that is disposed in the vicinity of the said die and roller assembly so as to splash the lubrication oil on the said profiled rolls (503a and 503b).

4. A cold rolling system as claimed in claims 1 , 3 wherein the said members are selected from load bearing structural components.

5. A cold rolling system as claimed in claim 1 wherein the driving system (Figure 7) comprises of

input shaft (708), one of the ends of the said shaft (708) is mounted with a pulley (710) for operably connecting with a prime mover such as motor wherein

the said shaft (708) is rotatably secured in the bearings mounted in the driving system housing (701), other end of the said shaft (708) is mounted with pinion gear (702) that is meshed with the crank gear (703);

the said crank gear (703) is mounted on crank gear shaft (706) that is rotatably secured in the bearing mounted said driving system housing

(701);

connecting rod (704) wherein one of the ends of the connecting rod (704) is operably mounted on the said crank gear (703) in the proximity of the gear teeth, the other end of the said connecting rod (704) operably connected to the said connector (505) (refer Figure 5) of the said die and roll assembly; the said pinion gear (702) and the crank gear (703) are disposed substantially in one horizontal plan on the surface of the housing (701); -the first bevel gear (707) that is mounted on the said crank gear shaft (706) inside the housing wherein the second bevel gear (710) is operably meshed with the said first bevel gear (707), the said second bevel gear (710) that is mounted on the output shaft (705) wherein the said crank gear shaft (706) and the said output shaft (705) are substantially perpendicular to each other;

base plate (709) on which the said housing is secured.

6. A cold rolling system as claimed in claim 1 wherein the feeding bed (Figure 8) comprises of front portion that is connected to the main housing (601) and rear portion connected to the feed and turn gear box;

connecting shaft (801) that is operably coupled to the said output shaft (705) of the said driving system, further the said connecting shaft (801) is operably coupled to the drive shaft cum guide bar (806) that is rotatably supported in the mounting brackets (802a and 802b) disposed at front and rear portion of the feeding bed;

feed screw (803) that is supported in the said mounting brackets (802a and 802b);

guide plates (804a and 804b) as well as feeding pusher trolley (805) are operably engaged in the said feed screw and are supported by the said drive shaft cum guide bar (806);

wherein the said feed screw (803) that is powered / rotated by the feed and turn gear box enables pipe blank feed in linear direction as well as intermittent partial rotation in tandem with the reciprocating motion of the said die and roller assembly.

7. A cold rolling system as claimed in claim 1 wherein the feed and turn gear box (Figure 9) comprises of

input shaft (901) that is mounted with gears operably engaged with turning mechanism (907) wherein the said mechanism and feeding gear (906) are mounted on the feeding shaft (902) wherein the said input shaft is coupled with the drive shaft cum guide bar (806) of the feeding bed and the said feed shaft is coupled with the feed screw (803) of the feed bed; the feeding gear (906) is further meshed with the turning gear (905) that is mounted on the turning spindle (903);

the input shaft (901), feeding shaft (902) and the turning spindle (903) are rotatably mounted in the housing (904)

wherein intermittent rotation of the mandrel rod along with intermittent rotation and feeding of the pipe blank are completed by rotating shaft (806) and the feed screw (803) in tandem with the reciprocating movement of the said die and roller assembly.

8. A cold rolling system as claimed in claim 1 operates wherein power from the prime mover (307) is transmitted to the pulley (710 / 953)

resulting in rotation of the pinion (702) and in turn crank gear (703); since the crank gear diameter is larger than that of the pinion (702), there is speed reduction and torque enhancement;

the rotation of the crank gear results in operation of the connecting rod

(704) which is coupled with the said connector (505) of the die and roller assembly;

this results in providing linear reciprocating motion to the said roller and die assembly which is secured (so as to restrict movement in translational direction) in the said guide bars (604a and 604b); the reciprocating motion of the said die and roller assembly results in rotation of the pinion (507) of the said die and roller assembly that is engaged with the rack (603);

the rotation of the said pinion (507) enables mutual rotation of the said roller gears (506a and 506b);

^■ such mutual rotation of the said roller gears (506a and 506b) results in mutual rolling of the said two profiled rollers (503a and 503b); the pipe blank that is to be cold rolled is fed in terms of intermittent rotation and linear feed with the help of feed screw that is operated with the aid of the said feed and turn gear box wherein input power for the same is derived from the drive system itself.

A cold rolling system as claimed in claims 1, 2 wherein the said die and roller assembly comprises of first and second stopper plates (520) and (521) wherein the said first stopper plate (520) is disposed vertically between the said taper plate assembly (502) and the said guide bush housing (501a); the said second stopper plate (521) is disposed vertically between the said guide bush housing (501b) and the said bearing housing (504b).

A cold rolling system as claimed in claims 1 , 2 wherein the connector (505) of the said die and roller assembly comprises of an eccentric pin (550) wherein the said pin comprises of substantially flat top cylindrical portion (561) provided provision for removably receiving screw / bolt (552), below the said cylindrical portion there is provided another cylindrical portion (560) of comparatively smaller diameter than the said top portion;

the said cylindrical portion (560) is press fitted in the first pin holding member (553) that is in the form of a substantially thick plate provided with a hole of corresponding diameter of the portion (560) so as to receive the said portion (560);

the said member (553) is adapted to receive the said screw/ bolt (552) that passes through the said top portion (561), the said member (553) is secured to the bracket (551) that is in the form of a plate;

below the said cylindrical portion (560), the said pin is provided with an offset cylindrical portion (555) wherein center of this offset cylindrical portion (555) and the centre of the said flat top cylindrical portion (561) are distanced apart;

the end portion (556) of the pin is of smaller diameter than the said offset portion wherein the centre of the end portion and the centre of the said flat top cylindrical coincide;

the said end portion is adapted to be pressfitted in the second pin holding member (554), this member is secured to the bracket (551);

end of the connecting rod (704) (Figure 7) is adapted to be fitted in the said offset cylindrical portion (555).

A cold rolling system as claimed in claims 1 , 7 wherein the feed and turn gear box comprises a shifter mechanism provided with a gear shifter (920) that is mounted on a shaft (921) such that the said shifter slides over the said shaft; the shifter is operably in connection with the shifting gear assembly (922) that is mounted on the splined shaft (923) to facilitate sliding of the said gear assembly to enable multiple feeds.

A cold rolling system as claimed in claims 1 , 5 wherein motor (752) of the said driving system is disposed on one of the vertical members of the said main housing wherein the input shaft (751) is operably connected at one end to the pulley and other end to the said pinion gear (702) wherein vertical disposition of the motor with the output shaft accessible at the top of the said main housing facilitates drive to the said pinion gear (702) from top of the drive unit;

13. A cold rolling system as claimed in claims 1-12 wherein the intermittent rotation angle is in the range of 55 to 60°.

14. A cold rolling system as claimed in claims 1-13 wherein linear feed is in the rage of 2 mm to 5 mm.