Title of Invention

"A MINIATURE SPINDLE UNIT FOR A TWO-FOR-ONE TWISTER"

Abstract

A miniature spindle unit, for a Two-for-One twister, of a diameter of 70-80 mm, having a spindle (1) providing twist to a feed yarn, said spindle (1) having positioned on the upper portion thereof a bowl (2), the bottom of the said spindle comprising a spindle pulley (3), an axle (4) holding the said spindle bowl (2) and the said pulley (3), said spindle axle (4) having fitted on the top thereof a pair of bearings (5), a housing (9) holding the said spindle pulley (3) and connected thereto having positioned therein a pair bearing on which the said spindle is rotating, a bobbin holder (10) for holding a supply bobbin stationary, the said bobbin positioned over the said two bearings (5) fitted on the top of the said spindle axle, a stationary twist blocker unit (19) mounted centrally on top of the said bobbin holder for preventing twist form flowing backwards wherein there are provided magnets (14) such as an internal magnet unit (15) positioned inside the bobbin holder and an external magnet unit (16) is fixed onto the said spindle bearing housing (9) which is stationary, said magnets being positioned at a predetermined suitable distance from the bearing in order to avoid magnetic flux affecting the said bearings (5) while at the said time the said internal and external magnets attracting each other thereby holding the bobbin holder stationary during spindle running, a gap provided between the said bobbin holder and the said spindle to cause a controlled air flow so as to avoid heating of the bearings.

Full Text

The present invention relates to a novel miniature spindle unit of the diameter of size 70 to 80 mm. The spindle unit of the present invention is used for a Two-for One twister. The present invention has opened the way to better machine utilisation by high twist market. The invention is able to solve many of the problems inherent in the existing conventional twisting machines. The invention is also very useful, since this machine requires very less electrical power as compared to the other conventional twisting machines under identical processing conditions. The cost of power per kg., of production also is much less than that of the conventional twisting machine. Regarding productivity, the miniature spindle unit allows higher productivity due to much higher speed than that of conventional twisting machines. Accordingly, in comparison to conventional twisting machines, the miniature spindle unit of the present invention can produce approximately 3 to 4 times more. Regarding quality, the yarn produced by miniature spindle unit of the present invention is much superior than that of conventional twisting machines, since it has knotless package and also has better uniformity in balloon and winding tension and the twist variation. Conventionally the segment of yarn such as fine denier yarns with high twist per meter levels is being mainly catered by One-for-One Twisters, which have various limitations such as less production, poor quality of processing, more manpower requirement and the need for more space. Partially, it is also catered by Two-for-One Twisters with comparatively higher diameter spindle, -which is not so cost effective. As opposed to this, One-for-One machine, although satisfying the economic factor, is unable to provide the desired quality in the yarn. A solution to the above problem was found in the miniaturization of the spindle unit for the Two-for-One Twister. In the process of miniaturization it was found that the 'positioning of the magnet and the gap/distance between the bobbin holder and the spindle bowl played a very important role. This is explained in the latter part of this text. The miniaturization of the spindle which necessitated numerous constructional improvements have been achieved by years of research taking also the help of the process of simulation with extensive use of computer aided design. Further this has not only extended the advantages of a smaller sizes to the spindle unit, but also the presence of lower yarn tension which results in less breakage and also lower power consumption. By virtue of the miniaturization of the spindle it is effective in running the machine at higher speeds thereby resulting in higher productivity. Besides this, the smaller size also reduces power consumption. In contract to the One-for-One Twister and the standard Two-for-One Twister, the present invention comprising of a miniature spindle unit is able to overcome the economics as well as the-quality problem faced in the production of the yarns. The balloon formation is a very complex feature and is critical in deciding the positioning of the magnet. Shape of the balloon depends upon a number of variables such as speed of rotation of the spindle, yarn delivery speed, thickness of the yarn (denier), air resistance which is determined by the atmospheric conditions such as temperature and humidity, the diameter of the spindle bowl and the height of the balloon. In accordance with the present invention there is provided a miniature spindle unit of a diameter of 70 to 80 mm for a Two-for-One Twister comprising a spindle providing twist to a feed yarn, said spindle having positioned on the top portion thereof a bowl, the bottom of the said spindle comprising a spindle pulley, an axle holding the said spindle bowl and the said pulley, said spindle axle having fitted on the top thereof a pair of bearings, a housing located below the said spindle pulley and connected thereto having positioned therein a pair of bearings on which the said spindle is rotating, a bobbin holder for holding a supply bobbin stationary, the said bobbin holder positioned over the said two bearings fitted on the top of the said spindle axle, a stationary twist blocker unit mounted centrally on top of the said bobbin holder for preventing twist from flowing backwards wherein there are provided magnets such as an internal magnet unit positioned inside the bobbin holder and an external magnet unit is fixed onto the said spindle bearing housing which is stationary, said magnets being positioned at a predetermined suitable distance from the bearing in order to avoid magnetic flux affecting the said bearings while at the said time the said internal and external magnets attracting each other thereby holding the bobbin holder stationary during spindle running, a gap provided between the said bobbin holder and the said spindle bowl so as to avoid heating of the said bearings due to air turbulence. Preferably a vertical distance of 12 to 32 mm between the top most bearing centre to the internal magnet centre is maintained. Preferably a horizontal distance of 25 to 35 mm between the spindle centre to the inside surface of the internal magnet is maintained. The invention comprises of two major improvements in the features of construction of the spindle units i.e., miniaturization and creation of an optimum gap between the bobbin holder and the spindle bowl. The reduction in the dimensions of the spindle involves a systematic, judicious and organized positioning of magnets in the spindle. The placement of the magnets becomes critical as they tend to either obstruct the yarn trajectory and due to their magnetic field, the distance of the magnets from the spindle bearing balls. Therefore, the positioning of the magnets constitutes an essential features of the invention which helps in high speed running with energy efficient rotation of the spindle bearing resulting into higher power saving. The above disclosed magnetic field is created by positioning magnet in the external magnetic unit fixed on the spindle bearing housing and in the internal magnetic unit, placed inside the spindle bowl. The internal and external magnets are positioned opposite to each other in order to attract each other thereby avoiding bobbin holder from rotating at the time of spindle running. Positioning of the magnets disclosed hereinbefore results in counter balancing of the magnetic field thereby eliminating the resultant force on the spindle bearing units. This in turn reduces the power consumption substantially. Another important feature of the present invention is the formation of an optimum gap between the bobbin holder pot and the spindle bowl. While the former is a stationary item the latter is a high speed revolving item. The high speed revolution inside a partially enclosed volume creates a lot of air current. The air current, which is generated, if properly utilized can help in cooling the spindle bearing units and a smooth outflow of air without any turbulence does not affect the power consumption. However, if this air current is not properly channeled, the turbulence increase the air resistance to the rotation of the bowl, causing higher power consumption and also decreased heat ventilation which further decreases the mechanical life of the bearing and their performance. The determination of the optimum gap to achieve perfect aerodynamic characteristics of the air generated, it arrived at by persons skilled in this art. The above disclosed features are critical since there is always difficulty in accommodating spindle bearings, magnets etc., and at the same time providing adequate space for yarn movement in a very limited space of spindle units. AH this is critical if the diameter of the spindle unit is reduced. On the other hand, if the diameter is more, this is not as important, since the distance of the magnet from the bearing will automatically be more and, hence, a little or not effect of magnetic force on the bearings; counter balancing of magnetic force is of less importance because the magnetic force will not be able to influence the heavy bobbin holder unit. The invention will now be described with reference to the accompanying drawings and the working of a Two-for-One Twister comprising a miniature spindle unit in accordance with the invention: Figure 1 illustrates the working of a Two-for-One Twister machine comprising the miniature spindle unit in accordance with the present invention. Amongst all twisting machines, two for one twister is considered to be the best having most advanced technology in twisting. As the name suggested a Two-for-One Twister is able to impart two twists in one revolution of the spindle. The yarn to be twisted is provided to the machine in the form of a cop-a particular package shape-which is winding of yarn in a biconical shape on plain cylindrical tube. It is then centrally placed on the top of the bobbin holder. Yarn from this supply package enters inside the twist blocker device, which has several holding points comprising of cup ceramics and highly polished steel balls. The number of holding points vary depending on yarn denier as well as twist to be processed. The yarn then passes downwards and passing through the hollow position of the spindle, emerges out of the ceramic eyelet placed at the bottom of the spindle bowl. Now this yarn goes upwards to the fixed yarn guide situated little above the twist blocker device and forms a balloon during spindle rotation. As the spindle rotates it imparts a twist to the yarn during its downwards passage which is inside the spindle and twist blocker. Another twister imparted during its upwards movement which is along the balloon trajectory and the two twists are added because of their unique opposite flow. The yarn thus twisted then moves further upwards through the fixed balloon eyelet to the overfeed roller. The overfeed roller does the functioning of extra feeding to reduce the tension of winding. The overfeeding can be varied depending on the type of yarn denier, twist etc. From this overfeed roller the yam then goes to traverse guide and then to takeup bobbin which rests on a cylindrical drum. The take-up package rotates by friction and the surface speed of the drum delivers motion to the take-up package, which is the final output of the machine. Since the drum rpm is constant for particular setting of machine, the winding speed of yarn and thereby winding tension remains same throughout the package formation irrespective of its diameter. With this a superior quality of package is obtained. The traverse guide has a reciprocatory motion, which is governed by a drive unit placed at one extreme side of the machine which is called the head stock or the drive end. This drive unit gives motion to the take-up drum as well as overfeed rollers and are inter related with spindle rotation through motor which is placed on the other extreme side called as tail stock or the motor end. The spindle is rotated with the help of a tangential belt from the same motor. The number of twist can be varied by simply changing one or two gears. 1-A - Take Up Flange Bobbin (Final Output) 2-A - Cylindrical Drum 3-A - Traverse Guide A-UPPER DECK 4-A - Overfeed Roller 5-A - Fixed Balloon Guide 6-A - Supply Bobbin (Cop) 7-A - Spindle 8-B - Take Up Flange Bobbin (Final Output) 9-B - Cylindrical Drum 10-B - Traverse Guide B - LOWER DECK 11-B - Overfeed Roller 12-B - Fixed Balloon Guide 13-B - Supply Bobbin (Cop) 14-B - Spindle Figure 2 illustrates the spindle unit for a Two-for-One Twister in accordance with the present invention. 1 - Spindle, 2 - Bowl, 4 - Spindle Axle, 5 - Bearings, 9 - Spindle Housing, 10 - Bobbin Holder, 28 - Supply Bobbin 12 - Pot, 15 - Internal Magnet, 16 - External Magnet, 17 & 18 Steel Plates for External & Internal Magnets, 19 -Twister Blocker Unit, 25 - Tagential Belt, 26 - Yarn Trajectory. Figure 3 illustrates the various components of a spindle. SPINDLE: Spindle (1) is the main part of the machine, which imparts twist in yarn. It mainly comprises of, bowl (2) spindle pulley (3) spindle axle (4) top (5) and bottom bearings (6) and ceramics (7). It is the most critical part, manufactured very accurately with the help of CNC machines and dynamically balanced (within a range of few milligrams). BOWL: The top part of the spindle is called bowl. Bowl is a light weight, aerodynamic shaped, hardened, highly polished item and is manufactured with utmost precision. SPINDLE PULLEY: The bottom part of the spindle is called spindle pulley. Power is transmitted through spindle pulley with the help of tangential belt. SPINDLE AXLE: The shaft which is holding the spindle bowl and pulley is called spindle axle. It is made of hardened steel with very high accuracy. SPINDLE HOUSING: Spindle housing (9) is the bearing housing for the spindle rotation. In between spindle housing and bottom bearing, a rubber sleeve (8) is provided which acts as vibration dampener. Figure 4 illustrates the various components of the Bobbin Holder. BOBBIN HOLDER: The main function of the bobbin holder (10) is to hold the supply bobbin stationary. It is comprising of bobbin holder housing (11) pot (12) and rubber sleeve (13). Supply bobbin is kept over the bobbin holder. Bobbin holder is placed over two bearings (5), which is fitted on the top of the spindle axle. BOBBIN HOLDER HOUSING: It is the housing for top bearings as well as internal magnets. In between this housing and top bearings, a rubber sleeve is provided mainly to dampen vibration. POT: Supply pot is an extension of the bobbin holder to prevent yarn from touching the supply bobbin specially at the time of machine start. The pots are hardened, highly polished and plated to minimize damage to yarn even if rubs against it. Figure 5 illustrates the details of the magnets employed in the invention. MAGNET: Magnetic field is created by putting magnets (14) (internal (15) inside the bobbin holder and external (16) fixed on the spindle bearing housing) opposite to each other so that they attract each other, thereby holding the bobbin holder stationary at the time of spindle running. STEEL PLATES: Steel plates both internal (17) and external (18) are provided at the back of magnets to increase the magnetic strength. Figure 6 illustrates the components of the Twist Blocker Unit. TWIST BLOCKER DEVICE: Twist blocker device(19) is the part which prevents twist from flowing backwards. This has several holding points which depend on the denier of the yarn and TPM to be processed. This consists of a vertical tube holder (20) top cover (25), disc (26) with a ceramic guide (21) on the top through which yarn enters and passes through several holding points comprising of ceramic holder (27) cup ceramics (22) and steel balls (23) and then emerges out of the bottom of the extension tube (24) before entering the spindle. It is mounted centrally on the top of the bobbin holder and is stationary. We claim: 1. A miniature spindle unit, for a Two-for-One twister, of a diameter of 70 - 80 mm, having a spindle (1) providing twist to a feed yarn, said spindle (1) having positioned on the upper portion thereof a, bowl (2), the bottom of the said spindle comprising a spindle pulley (3), an axle (4) holding the said spindle bowl (2) and the said pulley (3), said spindle axle (4) having fitted on the top thereof a pair of bearings (5), .a housing (9) located below the said spindle pulley (3) and connected thereto having positioned therein a pair bearing on which the said spindle is rotating, a bobbin holder (10) for holding a supply bobbin stationary, the said bobbin positioned over the said two bearings (5) fitted on the top of the said spindle axle, a stationary twist blocker unit (19) mounted centrally on top of the said bobbin holder for preventing twist from flowing backwards wherein there are provided magnets (14) such as an internal magnet unit (15) positioned inside the bobbin holder and an external magnet unit (16) is fixed onto the said spindle bearing housing (9) which is stationary, said magnets being positioned at a predetermined suitable distance from the bearing in order to avoid magnetic flux affecting the said bearings (5) while at the said time the said internal and external magnets attracting each other thereby holding the bobbin holder stationary during spindle running, a gap provided between the said bobbin holder and the said spindle to cause a controlled air flow so as to avoid heating of the bearings. 2. A miniature spindle unit as claimed in claim 2 wherein the said pair of bearings (5) are positioned as a top bearing and a bottom bearing. 3. A miniature spindle unit as claimed in claim 1 wherein the said bobbin holder has a housing (11) for positioning the said internal magnet and said top bearing (5). 4. A miniature spindle unit as claimed in claim 1 or 2 wherein the said external and internal magnetic units are provided with steel plates (17 & 18) at the back thereof in order to increase the magnetic strength on one side and to reduce the magnetic strength on the other side. 5. A miniature spindle unit as claimed in claim 2 wherein the said bobbin holder has a housing (11) for positioning therein the said internal magnet and the top bearing (5). 6. A miniature spindle unit as claimed in claim 5 wherein a rubber sleeve is provided between the said housing and said top bearing to dampen vibrations. 7. A miniature spindle unit as claimed in claim 1 wherein the said bobbin (10) extends into a supply pot (12) to prevent yarn from touching the said supply bobbin. 8. A miniature spindle unit, for a Two-for-One twister, substantially as herein described with reference to the accompanying drawings.

Documents:

485-del-1995-abstract.pdf

485-del-1995-claims.pdf

485-DEL-1995-Correspondence-Others-(17-03-2011).pdf

485-del-1995-correspondence-others.pdf

485-del-1995-correspondence-po.pdf

485-del-1995-description (complete).pdf

485-del-1995-drawings.pdf

485-del-1995-form-1.pdf

485-del-1995-form-13.pdf

485-del-1995-form-2.pdf

485-del-1995-form-29.pdf

485-del-1995-form-4.pdf

485-del-1995-form-9.pdf

485-del-1995-gpa.pdf

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