Title of Invention	AN UNIVERSAL MACHINE FOR MANUFACTURING AND/OR RECONDITIONING OF PROCESSORS LIKE CTC TEA ROLLERS
Abstract	The universal machine of the present invention provides chasing/cutting and milling facilities with automation duly integrated in a composite machine capable of manufacturing and reconditioning of processors such as CTC rollers, used in tea industry, and various other types of rollers having and/or requiring textured roller surface.

Full Text

The present invention relates to an universal machine for manufacturing and/or reconditioning of processors like CTC tea rollers. CTC stands lor crushing, tearing, curling, as used in tea manufacturing, in the usual terminology of tea processing. In the CTC type of tea manufacturing-steps, after the withering which involves moisture removal up to the required level of tea leaf, is put into CTC machines, basically, to process the withered leaf in special type of rollers which are called the CTC rollers. CTC rollers are basically a pair of rollers running in close proximity, typically, one roller having 70 and the other 700 revolutions per minute. The rollers are grooved in fine geometrical regularity at their surfaces, when the withered tea leaf is put in the gap between such rotating CTC rollers, the resulting product, eventually, cut (crushed), torn (tearing) and rolled (curling). Naturally, after continuous use, the rollers receive deformity at its surface features and requires reconditioning to extend its life. The machine of the present invention is of universal nature, with automated operation through programmable logic controller for the manufacturing and reconditioning of such class of rollers, as used in tea processing, as well as, can be used for similar purposes for other types of special rollers used in food processing and process equipment in chemical industry. The main usage of this invention is to provide an universal machine which is capable to manufacture and recondition processors such as CTC rollers as an automated machine which runs through programming as well as, if the need be, with manual interactions. This is universal because, once the job, in the form of circular cylinder of appropriate diameter, is mounted on the job holders, at the two ends of the cylinder, say, like the head-stock and tail-stock of a lathe machine, and appropriate types of cutting and milling tools are mounted on the tool-post and appropriate programming is applied to the drive units of the machine, the machine follows the sequence of metal cutting and milling and completes the generation of the grooves on the surface of the rollers to bring it into finished state. In this universal machine, the tool orientation, with respect to the job axis, according to the demand of the job of having circumferential and helical is incorporated, that is, tilting of the tool post is possible. The extensive prior art search in this class of machinery, that is, manufacturing of CTC rollers as well as, reconditioning of such rollers, indicated, no such machine of universal nature having the automation facility with it is available in the public domain, including in patent and literature database. In India, through market survey, three manufacturing companies were located namely M/S, Vikram India Ltd., Steelworth Ltd. And Sigma India Ltd., who manufacture the CTC rollers, but, then, in Lathe type of machines, one for chasing (cutting) and another for milling with the help of jigs and fixtures, involving only manual operation associated with multiple loading and unloading phases and the chances of inaccuracy in the finished products. A survey of the technical problem in the used rollers indicated that, the reconditioning of such used rollers are usually done in two distinct machine tools operations, one is chasing and next is milling. Chasing is actually, re-cutting the worn grooves on the surface to near accuracy and then milling the grooves to the required accuracy. Normally, chasing is done, on a lathe type of machine and after completing the chasing stage of finishing, the job is again mounted on another lathe type of machine to finish it with milling operation. Naturally, the total operation of reconditioning is quite cumbersome, time consuming and because, with number of manual actions, final accuracy is not achievable. But this being the compulsion in the vast tea industry, the problem remains as a challenge. Some of the demerits of the conventional way of manufacturing or reconditioning, that is, sharpen ing/resharpen ing of the CTC rollers are as follows: a. Two machine tools are required, one for chasing, another for milling. b. The cutter is tilted manually, resulting in low accuracy, every time it is done. c. Indexing of the roller is done manually after each helical groove is cut leading to stoppage of operation and chance of propagating error. d. The speed and direction of rotation of the lead screw in the lathe like machine tool requires to be changed with gear shifting lever, every time , for each helical groove to be cut, for the carriage movement having the tool post on it is synchronized with the help of the lead screw. This manual change over, several times, contributes to operator's fatigue. e. Helical grooves may have varying depth due to wrong engagements of the cutting tool-tip. The main object of the present invention is to provide an universal machine for manufacturing and/or reconditioning of processors like CTC tea rollers which obviates the drawbacks as detailed above. Another object of the present invention is to provide an universal machine which is capable to finish the job of chasing and milling involved in the manufacturing /reconditioning processors such as CTC rollers, in one machine tool, instead of two machines, as is being done at present. Still another object of the present invention is to provide an automated machine tool for the purpose of chasing and milling of the CTC rollers, through programmable electronic interface, with optimum parameters, for such rollers, such as, number of grooves, helix angle, depth of grooves, and if needed to revert to manual operation. Yet another object of the present invention is to create low cost automation in the reconditioning of CTC rollers, to extend its further usability. The novel machine of the present invention provides chasing/cutting and milling facilities with automation duly integrated in a composite machine capable of manufacturing and reconditioning of processors such as CTC rollers, used in tea industry, and various other types of rollers having and/or requiring textured roller surface. In the drawings accompanying this specification the universal machine of the present invention has been depicted in figures 1 and 2. In figure 3 is shown a typical CTC roller. In Figure 1, a schematic view of the machine of the present invention is shown, wherein the various parts are: 1. Floating differential drive unit (FDDU): FDDU is not fully visible in this three dimensional diagram but its main drive units, that is, the two induction motors 13 and 14, as well as the belt pulley 21 is visible. Details of FDDU are given in fig. 2 of the drawings. 2. Tail end gear box. 3. Main Lead screw. 3a. Cross Slide Lead Screw. 4. Tail end stock for holding the roller. 5. Job/roller which is to be machined. 6. Headstock for holding the roller, the headstock also houses gear train. 7. Milling head which holds the milling cutter capable of being tilted according to requirements 8. Chasing/cutting tool holder which holds the cutting tool (this is also called chaser). 9. Cross Slide to manipulate the tool holder (8) with respect to the job. 9a. Saddle 10. Gear train for milling. lOa. and lOb. Attachments for auto-indexing. 11. Attachment for tool holder (chaser) positioning. 12. Electronic automation control mechanism. Figure 2 of the drawings shows the details of an embodiment of Floating Differential Drive Unit (Item 1 of Figure 1) which is a subassembly of the total machine and which facilitates the milling cutter to travel slowly in the required direction, during cutting operation, as well as the rapid return of the milling cutter (in the opposite direction) to come back to the starting point, in the non-cutting phase. This facility creates a part of low cost automation for the machine in the form of a quick return mechanism for the milling tool with the assemblage of the following components. 13. Induction Motor 14. Induction Motor 15. Belt Pulley 16. Belt Pulley 17. Clutch 18. Dual clutch unit (that is, the sub unit which is having the two clutches, 17 and 20, at its ends). 19. Belt pulley 20. Clutch 21. Belt Pullev 22. Output shaft 23. Belt pulley 24. Pulley of the tail end gear box to receive the power and motion into the tail end gearbox (2) from the Floating differential drive unit (2) The first sequence of operation of the Floating differential drive unit: Power and motion reaches from the induction motor (13) to the belt pulley (15) and then reaches the belt pulley (21), at this stage, the clutch (17) is engaged (while the clutch 20 remains disengaged), power and motion reaches belt pulley (23) via the output shaft (22) and finally reaches the pulley (24) of the tail end gear box (2). The second sequence of operation of the Floating differential drive unit: Power and motion reaches from the induction motor (14) to the belt pulley (16) and then reaches the belt pulley (19), at this stage, the clutch (20) is engaged (while the clutch 17 remains disengaged), power and motion reaches the belt pulley (23) via the output shaft (22) and finally reaches the pulley (24) of the tail end gear box (2). Automation logic provided by the electronics is such that, while in operation, the milling tool holder, goes forward to get engaged with the job (roller) and milling operation is continued when the job is rotating and the tool point is traversing slowly along the length of the job. After the completion of the milling operation, the tool holder disengages itself from the job and comes back (traversing backward along the length of the job) to the starting position in fast speed. This engagement and disengagement of the milling tool, with the job, in different predetermined speeds has been achieved through the introduction of this inventive step of providing a floating differential drive unit which allows the operation of the machine to set the depth of cut, every time, not stopping the machine and reducing the idle period of the milling cutter The time management in finishing the job has been greatly improved by this inventive step of providing a floating differential drive unit (FDDU). Accordingly the present invention provides an universal machine for manufacturing and/or reconditioning of processors like CTC tea rollers, which comprises a main frame mounted headend stock (6) and tailend stock (4) having spindles capable of holding rotatably and horizontally a job (5) such as a roller to be machined, the said tailend being provided with a floating differential drive unit (1) connected by means such as a belt pulley (24) and a tailend gear box (2) to a main lead screw (3) capable of driving a horizontally placed saddle (9a) having a cross slide lead screw (3a) capable of driving a horizontally movable cross slide (9) provided with a milling head (7) and a chasing/cutting tool holder (8) placed diametrically with respect to the job/roller to be machined, the said headend stock (6) being provided with known auto-indexing attachments (lOa, lOb), electronic automation control mechanism (12), cutting tool/ chaser holder positioning attachment (11) and connected via gear train (10) to the said main lead screw (3) and cross slide lead screw (3a). In an embodiment of the present invention the floating differential drive unit (1) is essentially capable of providing slow drive to the milling cutter (7) during cutting phase and rapid return to the starting point in the non-cutting phase. In another embodiment of the present invention the floating differential drive unit (1) used consists of a dual clutch unit (18) having electromagnetic clutches (17) and (20) situated at either ends, each of the said clutches (17,20) being provided with a belt pulley (21) and (19) connected through corresponding belt pulley (15) and (16) to respective induction motor (13) and (14), the said dual clutch unit (18) being provided with a drive shaft (22) and a belt pulley (23) corresponding to belt pulley (24) of tail end gear box (2). In still another embodiment of the present invention the electronic automation control mechanism (12) is essentially capable of providing programmed control to the main lead screw (3), cross slide lead screw (3a) and auto-indexing attachments (lOa) and (lOb). In yet another embodiment of the present invention the electronic automation control mechanism (12) used consists of a programmable logic controller coupled with encoders, stepper motors, electromagnetic clutches and proximity switches. In a further embodiment of the present invention the milling head (7) and cutter is provided with an inbuilt micrometer arrangement consisting of worm wheel and vernier scale. In an embodiment of the present invention the cutting tool/chaser holder positioning attachment (11) is essentially capable of providing incremental positioning at the required pitch to the cutting tool/chaser (8). In another embodiment of the present invention the cutting tool/chaser holder positioning attachment (11) consists of a stepper motor coupled to a speed reducer and an electromagnetic clutch. In still another embodiment of the present invention the cross slide lead screw (3a) is coupled with a speed reducer and a stepper motor in such a manner as to enable both chasing and milling operation. In yet another embodiment of the present invention the headend stock (6) spindle is coupled through a worm gear assembly and a belt pulley arrangement to a prime mover such as an induction motor. In another embodiment of the present invention the auto-indexing attachment is connected via a worm shaft of a worm gear assembly to a stepper motor coupled with a speed reducer. The present invention provides an universal machine for manufacturing and/or reconditioning of processors like CTC tea rollers such as shown in figure 3 of the drawings. The novel machine of the present invention comprises a floating differential drive unit (1) connected to a gear box (2) through a belt pulley (24). The gear box (2) drives a lead screw (3) which drives a saddle (9a) carrying cross slide lead screw (3a), milling head (7), cutting tool holder (8) and the cross slide (9). The job (5) to be machined is held between head stock (6) and tail stock (4). The head stock (6) receives power from the lead screw (3) via gear train (10), also for indexing of the job, via attachments for auto-indexing (lOa) and (lOb). The automation control mechanism of the machine comes from the electronic console (12) where the programmable logic controller is situated and acts through encoders, stepper motors and electromagnatic clutches associated with the attachment for auto-indexing(lOa) and (lOb), and lead screw (3) and the lead screw (3a). In the present invention the floating differential drive unit (FDDU) attached to this machine provides the facility of automation of traverses of the milling tool in different speeds in the state of metal removal and in idle state. The said FDDU comprises of two induction motors (13) and (14) connected to dual clutch unit (18) through the belt pulley (21) & (15) and the belt pulley (19) & (16). The two clutches (17) and (20) are situated at the either ends of the unit (18). The power reaches the pulley (24) of the gear box (2) through output shaft (22) of the FDDU and the belt pulley (23). In the present invention, the machine is made to work in auto mode with the help of PLC (Programmable Logic Controller), encoders, stepper motors and electromagnatic clutches as well as this machine can also run in manual mode, if so chosen. The complete description of the universal machine of the present invention is as follows. The schematic view of the machine which is shown in Fig. 1 of the drawings comprises of headstock (6) and tailstock (4) for holding the roller (5) to be machined. Milling head attachment (7) holds the milling cutter. This milling head along with the milling cutter is capable of tilting to the requirement due to the inbuilt micrometer arrangement consisting of worm wheel and vernier scale. For cutting circumferential groove on the cylindrical job (5), the cutting tool is attached to the tool holder (8). This cutting operation, in the case of CTC tea roller, is called chasing and the cutting tool is called chaser. The attachment for chaser positioning (11) comprising of a stepper motor coupled to a suitable speed reducer and an electromagnatic clutch facilitates the incremental positioning of the cutting tool (chaser) at the required pitch for machining circumferential grooves. However, for a longitudinal travel of the saddle (9a) during milling operation, a floating differential drive unit (FDDU) (1) which has been shown fully in Fig. 2, is used to achieve different speeds of rotation and direction of the main lead screw (3). For, this lead screw (3) transfers the drive motion from FDDU (1) to the saddle (9a). The saddle(9a), while in milling phase, travels slow in the longitudinal direction (along the axis of the job), when the milling cutter is engaged in milling. After the completion of one travel of milling, the milling cutter gets disengaged from the job and comes back to the starting position (home position), with faster speed. FDDU offers this 'differential' speed and direction facility of the saddle(9a), while the machine is always in power mode, that is, the machine need not to be stopped, to bring the milling cutter to its starting point to apply the next pass of cut. FDDU thus contributes in the novel process of low cost automation by a non-obvious inventive step. The floating differential drive unit comprises a dual clutch unit (18) which receives power alternatively from two induction motors (13) and (14) through belt pulleys (15) & (21) and (16) & (19) at different speeds in opposite directions with the help of the electromagnetic clutches (17) and (20) for forward cutting and rapid return respectively and eventually supplies the power and motion to the tail end gear box (2) through pulleys (23) & (24). The chaser tool holder (8) is mounted on the front side of the cross slide (9) where as milling head (7) is mounted on the rear side of the cross slide (9). The cross slide lead screw (3a) is coupled with a speed reducer and a stepper motor for both chasing and milling operation. During cutting/chasing operation, the cross slide (9) will move gradually towards the job (roller) and engage the cutting tool on the cutting tool holder (8) in the cutting operation, through specified depth of cut. Once the cutting operation is completed, the cross slide (9) with the cutting tool on (8) will retract to its initial position of disengagement. For milling operation, the cross slide (9) which also accommodates the milling head (7) at the backside of the machine, is set at a position as per required depth of cut by giving only required incremental rotation to the stepper motor which drives the cross slide lead screw (3a). The forward (comparatively slow) and return (comparatively fast) movements of the saddle (9a) are synchronized with the forward and return movements of the cross slide (9) using the signals from proximity switches (not shown in the drawings) situated at appropriate locations, as inputs to the programmable logic controller (PLC) located at Electronic console for automation (12). For cutting (chasing) operation the head stock (6) spindle (which holds one end of the job to be machined and imparts rotation to it) is directly driven by an induction motor through a belt pulley arrangement and worm gear assembly, as a constituent of the head stock (6). For milling operation the head stock spindle receives power from either of the two induction motors (13) or (14) coupled to the floating differential drive unit FDDU (1). Then the power propagation route from FDDU (1) to head stock (6) spindle is through the tail end gearbox (2), main lead screw (3) and the gear train for milling (10). For, (1) supplies power to (2), then to (3), then to (10) and finally to (6). For auto indexing of the job, that is, defining of the starting point on the surface of the job, for the commencement of machining, a stepper motor coupled with a speed reducer has been provided to the head stock (6) via a worm shaft of a worm gear assembly. The entire machine can be used for cutting (chasing) and milling of CTC type rollers in this single universal machine, following the milling operation after the cutting (chasing) operation. Thus with single loading of the job, a cylindrical used roller or a fresh cylindrical bar can be manufactured, sharpened or resharpened without any interruption of the machine sequences, as an automatic process, with the help of programming through Programmable Logic Controller (PLC). Moreover, this universal machine can be used either in manual mode or in auto mode, in the event of any problem with the PLC facility. The following example is given by way of illustration of the present invention and should not be construed to limit the scope of the present invention. A couple of CTC tea rollers were reconditioned by an expert machinist using existing machine tools and the universal machine of the present invention. Example-1 Accuracy of the CTC tea rollers sharpened on the existing machine tools was measured individually and also in assembled pair condition. The cumulative error in chasing was found to be of the order of 2mm. The rollers were found to touch at various locations in assembly. This shows that it is not possible to do sharpening/resharpening on the existing machine tools with required accuracy. However, the machine of the present invention provided a cumulative pitch accuracy of about 80 microns which facilitates proper meshing of a pair of rollers. Another important factor is the equal spacing of helical grooves on the circumferences of the roller. The accuracy obtained with the machine of the present invention was of the order of 0.072 degree using encoder of 5000 PPR ( Pulse Per Revolution). Encoder of higher PPR will give higher accuracy. The machine of the present invention produced depth of cut within variation of 3.2 microns using an encoder of 5000 PPR. Thus, it is obvious that the rollers produced/resharpened on the machine of the present invention is of much greater accuracy and thereby result in production of properly matched pair of CTC or special purpose rollers. While in experimentation with the invented machine, involvement of the human-operator was much reduced due to the inbuilt automation of the process and due to the usability of this universal machine both for cutting/chasing and milling. Such operation, in prior art, needed two machines, one for cutting and another for milling, and every time it needs loading/unloading and indexing of the job. Now, in one loading and programming through PLC, the processing of the metal removal has become automated. The novelty of this machine rests on its universal nature meaning that once the job is loaded across the head stock and the tail stock then the mechanical and electronics hardware of the machine shall allow the machine to run in automatic fashion till the job is completed to satisfaction. Moreover, it is an universal metal removal machine, not found in the public domain, to function in sequence, both for the phases of metal cutting as well as for milling, that is, it is offering both the facilities of fine cut and very fine cut on the metals. The machine is capable to manufacture not only CTC type tea rollers but also various types of rollers (processors) having different types of textures on the surface as used in food or chemical engineering. The inventive steps resulting in the said machine includes an invented unit, FDDU, as its part, that is capable to offer the flexibility of making an object (here the milling cutter) to traverse in different speeds in different directions, whenever required, to reduce the idle period in the metal removal process. This is not like any existing device available in the public domain. The main advantages of the present invention are, 1. The floating differential drive unit (FDDU) makes this universal machine an excellent universal type facility where the milling head can return with faster speed to the starting position after completing one round of metal removal operation in slower speed and can repeat such movements, always, in slow and fast speed, till the job is over. 2. Metal cutting/chasing and milling can be completed in a single set up with a single loading and unloading of the job. 3. Very high accuracy in pitch distance of circumferential grooves due to automated operation of the machine. 4. Depth of circumferential grooves are obtained with minimum variations. 5. Helical grooves are more uniformly spaced due to auto-indexing operation. 6. Milling cutter can be set much more accurately to the desired helix angle. 7. Due to high accuracy in sharpening/resharpening, the rollers will have minimum error in assembly and the end products, such as, tea product, in the case of CTC rollers, will be more acceptable in quality.Human-operator's contribution to the entire functioning of this machine is minimum, with minimized down time. We claim : 1. A universal machine for manufacturing and/or reconditioning of processors like CTC tea rollers, which comprises a main frame mounted headend stock (6) and tailend stock (4) having spindles capable of holding rotatably and horizontally a job (5) preferably a roller to be machined, the said tail end being provided with a floating differential drive unit (1) connected by means preferably a belt pulley (21) and a tail end gear box (2) to a main lead screw (3) capable of driving a horizontally placed saddle (9a) having a cross slide lead screw (3a) capable of driving a horizontally movable cross slide (9) provided with a milling head (7) and a chasing/cutting tool holder (8) placed diametrically with respect to the job/roller to be machined, the said headend stock (6) being provided with known auto-indexing attachments (10a, 10b), electronic automation control mechanism (12), tool holder positioning attachment (11) and connected via gear train (10) to the said main lead screw (3) and cross slide lead screw (3a). 2. A universal machine as claimed in claim 1, wherein the headend stock (6) spindle is coupled through a worm gear assembly and a belt pulley arrangement to a prime mover preferably an induction motor. 3. A universal machine as claimed in claim 1, wherein the floating differential drive unit (1) is essentially capable of providing slow drive to the milling cutter (7) during cutting phase and rapid return to the starting point in the non-cutting phase. ' 4. A universal machine as claimed in claims 1-3, wherein the floating differential drive unit (1) used comprises of a dual clutch unit (18) having electromagnetic clutches (17) and (20) situated at either ends, each of the said clutches (17,20) being provided with a belt pulley (21) and (19) connected through corresponding belt pulley (15) and (16) to respective induction motor (13) and (14), the said dual clutch unit (18) being provided with a drive shaft (22) and a belt pulley (23) corresponding to belt pulley (24) of tail end gear box (2). 5. A universal machine as claimed in claims 1-4, wherein the electronic automation control mechanism (12) comprises of a programmable logic controller coupled with encoders, stepper motors, electromagnetic clutches and proximity switches, in a manner as to be capable of providing programmed control to the main lead screw (3), cross slide lead screw (3a) and auto-indexing attachments (10,10b). 6. A universal machine as claimed in claims 1-5, wherein the milling head (7) and cutter is provided with an inbuilt micrometer arrangement consisting of worm wheel and vernier scale. 7. A universal machine as claimed in claims 1-6, wherein the auto-indexing attachment is connected via a worm shaft of a worm gear assembly to a stepper motor coupled with a speed reducer. 8. A universal machine as claimed in claims 1-7, wherein the cutting tool/chaser holder positioning attachment (11) consists of a stepper motor coupled to a speed reducer and an electromagnetic clutch, so as to be capable of providing incremental positioning at the required pitch to the cutting tool/chaser (8). 9. A universal machine for manufacturing and/or reconditioning of processors like CTC tea rollers substantially as herein described with reference to the example and drawings accompanying this specification.

Documents:

52-DEL-2002-Abstract-(15-12-2008).pdf

52-del-2002-abstract.pdf

52-DEL-2002-Claims-(15-12-2008).pdf

52-del-2002-claims.pdf

52-del-2002-complete specification (granted).pdf

52-DEL-2002-Correspondence-Others-(15-12-2008).pdf

52-del-2002-correspondence-others.pdf

52-del-2002-correspondence-po.pdf

52-del-2002-description (complete).pdf

52-del-2002-drawings.pdf

52-del-2002-form-1.pdf

52-del-2002-form-18.pdf

52-DEL-2002-Form-2-(15-12-2008).pdf

52-del-2002-form-2.pdf

52-DEL-2002-Form-3-(15-12-2008).pdf

52-del-2002-form-3.pdf