Title of Invention

SLIVER SPINNING FRAME

Abstract

A silver spinning frame comprises: a lattice gill primary drafting zone (A) fitted on the top of said spinning frame; and a secondary drafting zone (B) fitted between two horn brackets (H) of said spinning frame; a wharve (W1) connected to a large package cylindrical flyer (D1) having an air guard (D2); take-up bobbins (R) mounted on bobbin carriers (G), having a self-adjusting drag control/braking mechanism for controlling the speed of the bobbin relative to the weight of the yarn wound on the bobbin, said bobbins sitting on spindles (E1) and being rotable by the pull of the yarn imparted by the rotation of the flyer; friction-free reinforced lifter brackets (K1) for supporting and guiding the up and down movement of the bobbin rails (BL) of a bobbin rail rack (Rr) said spindles, bobbins and bobbin carriers fitting within the bobbin rail rack, said brackets supporting a tangential drive (TD) for said spindles, and each bobbin rail having a gear and driving arrangement engageable with said tangential drive.

Full Text

The present invention relates to Sliver Spinning frame. Jute industry is more than 100 years old and has been playing a vital role in the economy of West Bengal and Bangladesh. But the industry is facing high manufacturing costs, mainly due to low productivity. One major reason for this is the use of antiquated machinery with low productivity and as a result high cost of labour engaged. In contrast, synthetic substitutes for packaging, bulk handling means etc have proved to be much cheaper and attractive. Jute mills in Europe closed down on account of high labour costs. As a result, the prospects of jute industry in India and Bangladesh brightened up. But Indian jute mills found it difficult to meet the stringent quality requirements of European weavers with the existing machines. TO compensate for increase in labour costs, the mills resorted to cost-cutting measures which deteriorated machinery as well as quality. Jute industry cannot afford to invest in new machinery. Today the jute industry needs to increase productivity and quality with less expenditure on labour per ton of product and less expenditure on energy. It also requires to acquire capability to cater to wider range of product and versatality of the emerging market. The machinery and processes to be developed should be cost-effective and should not call for heavy investments. In the prior art spinning frame, jute sliver (usually made of low quality jute and jute waste) is processed through a heavy yarn system of two-passage drawing and fed from a sliver can through a top conductor. The sliver is then drawn in by retaining roller and retaining pressing roller to pass through the nip of "V roller and "V" pressing roller to the nip between bottom roller and Bottom pressing roller. These rollers control the drafting of the sliver between the retaining roller and the retaining pressing roller and between the bottom roller and the bottom pressing rollers. The yarn is then passed over a detector sleeve which triggers off a mechanical system for stopping the sliver in the event of breakage of the yarn. The drafted material is then drawn through a wharve to an eye located at the bottom end of a two-leg flyer. The flyer runs at about 2000 R.P.M. Due to the difference in the speed of the flyer and the speed of the bottom roller, the yarn is twisted. The twisted yarn is wound on a bobbin fitted on a bobbin carrier and spindle. The spindle is static and hence is called as "dead spindle". In this system, bobbin rail of a bobbin rail rack moves up and down due to up and down movement of lifter brackets on which the bobbin rail sits. The lifter bracket is moved up and down by a cam and lever arrangement. The flyer, which is attached to wharve, rotates by means driven by a heavy cylinder which in turn is driven directly by an electric motor through an endless belt (not shown). While the wharve and the flyer rotate and the bobbin which sits on the bobbin carrier turns with the pull of the yarn, the spindle remains stationary. Friction blobs/corck rings control the relative speed of the bobbin carrier by drag/braking action. The existing 51/2" pitch V Roller Spinning frames are for short-fibre spinning of low quality (waste constituting majority) heavy yarn required for weaving sacks. Its rated operating speed is 2100 R. P. M and requires at least one operator to run a machine. V roller drafting was designed keeping in mind the spinning requirements of short fibres. Generally mills spin Skg. weft yarn (sacking weft yarn) between 25 to 34 lbs/spangle with lowest batch. When a mill gets export order for H.Y. of 20-36 lbs, it is spun in the 5 1/2 V Roller Spinning frame which does not have proper drafting system for 100% long jute which is essential for export quality yarn. As a result the yarn quality is substandard ; but because of plying into Twine (i.e. 29 lbs x 2 ply. etc.) the deficiency is somewhat reduced to a level acceptable to non-critical buyers. The mills have have no option because there is no suitable machine with them. To summarize, the known spinning frames suffer from the following disadvantages : a) Very low production due to a limiting speed of around 2000 R.P.M only. b) Higher in labour cost as the operator has to look after only one machine of 80 spindles. c) Cannot spin lighter count for conventional Hessian or other products. d) Its single zone V roller drafting is not suitable for spinning high quality heavy yarn suitable for export market. e) The existing machine is ear-marked and used for Skg. weft yarn (sacking weft yarn) which is the lowest quality heavy yarn for weaving coarse bags only. f) Due to heavy drag and other associated deficiencies usually the operating efficiency is also quite low. The present invention proposes a V roller sliver spinning frame to overcome the disadvantages of prior art machines. The present invention provides a silver spinning frame comprising : a lattice gill primary drafting zone fitted on the top of said spinning frame ; a secondary drafting zone fitted between two horn brackets of said spinning frame ; a wharve ; a large package cylindrical flyer having an air guard and connected to said wharve ; take-up bobbins mounted on bobbin carriers, said bobbin carriers having a self-adjusting drag control/braking mechanism for controlling the speed of the bobbin relative to the weight of the yarn wound on the bobbin, said bobbins sitting on spindles and being rotable by the pull of the yarn imparted by the rotation of the flyer ; friction-free reinforced lifter brackets for supporting and guiding the up and down movement of the bobbin rails of a bobbin rail rack said spindles, bobbins and bobbin carriers fitting within the bobbin rail rack, said brackets supporting a tangential drive for said spindles, and each bobbin rail having a gear and driving arrangement engageable with said tangential drive. The spindle may be a dead spindle mounted on a bobbin carrier, said bobbin carrier being mounted on said bobbin rail rack. For a wider range, i.e. LY version, the spindles will be live and will be driven by a tangential belt and a motor drive arrangement. In this case, bobbin carrier is omitted. Spindle and wharve brake may also be provided. The present invention further provides a sliver spinning frame wherein said spindle is a dead spindle mounted on said bobbin rails, said spindle and said bobbin carrier being fitted on the spindle, and said bobbin sitting on said bobbin carrier. The dead spindles may be fitted on said bobbin rails by means of a nut and a washer passing through the base of each said swindle. With reference to the drawings accompanying the specification, the said spindles fitted with bobbin drive flange "B1 (fig 12) can also be live spindle (fig. 6) driven by a tangential belt "TD" and a motor drive "TDM" said live spindles "E1" being fixed on the bobbin rails "BL" of the bobbin rail track, there being a braking device "BK" on brake drum "D" for stopping the spindle when required. An apron and tumbler roller secondary drafting zone may be provided, said drafting zone comprising: a convex apron plate provided with an apron plate roller at each end, and two grooves on the sliver path; an endless rubber apron fitted on said apron plate, said apron passing over a jockey roller to enable tensioning of said apron; a driving roller for drivingly supporting said apron; and tumbler rollers mounted on said apron plate. The apron and tumbler roller assembly can be mounted between a pair of horn brackets, each said bracket having a groove for receiving the pins of said apron plate, and grooves for receiving pins of the tumbler rollers. The bobbin carrier may comprise an auto-drag bobbin carrier provided with inner spring-loaded nylon blobs and outer felt blobs. The lifter bracket is preferably mounted on ball bearing provided at its top and bottom ends, said bobbin rails sitting on said lifter brackets. With reference to the accompanying drawings, the said wharve (fig.11) may comprise an outer case "O" fitted in bearings, BB, B2, & thrust bearing "A", a yearn tube "YT" passing centrally through a bottom cap "BF" at one end of said outer case and having its other end passing through said flyer rail "FR" and a top flange "TF" fitted to the other end of said outer case, said wharve being mounted on said flyer rail. In a preferred embodiment, the bobbin rail rack sitting on the said bobbin rail "Btr" supports a rack shaft "RS" for shifting the position of said rack shaft forward and downward to increase the distance between said flyer and said rail rack. This invention also provides an apron and tumbler roller assembly for sliver spinning frame comprising a convex apron plate provided with an apron plate roller at each end, and two grooves on the sliver path; an endless rubber apron fitted on said apron plate, said apron passing over a jockey -7- roller to enable tensioning of said apron; a driving roller for drivingly supporting said apron; and tumbler rollers mounted on said apron plate. The apron and tumbler roller assembly may be mounted between a pair of horn brackets, each said bracket having grooves for receiving the pins P1 of said apron plate and grooves for receiving pins of the said tumbler rollers. Inside each pair of horn bracket H (fig. 10G), 2 Nos. stop motion detector assy. DL are fitted to weight lever WL and Retaining Roller pressing boss R1 (fig. 4) to disengage the pressing boss for stopping the sliver when the yarn of any bobbin breaks during operation. This invention further provides an auto-drag bobbin carrier for a sliver spinning frame comprising a bobbin carrier provided with inner spring-loaded nylon blobs and outer felt blobs. This invention additionally provides a wharve for a sliver spinning frame comprising an outer case fitted in bearings, a yarn tube passing centrally through a bottom cap at one end of said outer case and having its other end passing through a flyer rail; a top flange fitted to the other end of said outer case, said wharve being mounted on said flyer rail. This invention further provides a live spindle for a sliver spinning frame comprising a spindle fixed on a bobbin rail by means of a flanged bearing housing, a tangential tape with pulley for driving said spindle; and a brake drum and brake device for stopping the motion of said spindle. A number of live spindles E1, usually 8 nos., are fitted on each bobbin rail and on the first spindle from the left of each bobbin rail, a spur gear SG is fitted which is driven by a spur gear pulley assembly SGP for driving spindles of each bobbin rail by a tape TBL (12C), There are 10 bobbin rails each having 8 nos. spindles and there are equal no. of bobbin rails with spindles and as a spare set to easily replace the set when full with yarn, by the spare set with empty bobbins fig. 12D is the side view of drive arrangement. This invention also provides a bobbin rail rack for a sliver spinning frame, wherein said rack is mounted on a bottom rail and a rack shaft is provided, so that by movement -8- of said rack, the position of the rack shaft is shiftable forward and downward. The present invention is hereafter described with reference to the accompanying drawings, wherein *, Figs. 1 and 2 show spinning frame of prior art with Fig. 2 being a continuation of Fig. 1; Figs. 3 and 4 show the lifter bracket shown in Fig. 1; Figs. 5 and 6/show schematic view of two embodiments of the present invention, namely, using a dead spindle and using a live spindle respectively; Fig. 7 is a schematic view showing the spindle; Fig. 8 shows an exploded view of the flyer arrangement having two legs; Fig. 9 shows a flyer of cylindrical form; Fig. 10 shows an exploded view of the bobbin rail with dead spindle and bobbin carrier. Fig. 10A shows an improved apron and tumbler roller system on a convex apron plate; Fig. 10B shows a sectional view of Fig. 10A; Fig. 1OC shows an improved horn bracket for the system of Fig. 10B; Fig. 10D shows the apron plate and apron roller of Fig. 10A in enlarged view; Fig. 10E shows the horn brackets of Fig. 19 in side view ; Fig. 10F shows a plan view of Fig. 10E; Fig. 10G /shows in plan view the system of Fig. 10B; Fig. 11 shows an improved wharve of the present invention; Figs. 12, 12A and 12B show a live spindle with braking arrangement, its side view and its plan respectively; Figs. 12C, and 12D show the arrangement of live spindles; Fig. 13 shows an improved lifter bracket of the present invention; Fig. 13A shows plan view of Fig. 13; Fig. 13B shows enlarged view along section line A-A in Fig. 13; Fig. 13C shows a sectional view along section line B-B in Fig. 13; Figs. 13D and 13E show side views along arrows X and Y in Fig. 13; Fig. 13F shows sectional view along sectional line C-C in Fig. 13; Fig. 14 shows a modified bobbin rail rack arrangement of the present invention; Fig. 14A shows side view of Fig. 14; Fig. 14B shows plan view of Fig. 14; Fig. 14C shows a view along section line A-A in Fig. 14; Fig. 14D shows prior art bobbin rail rack arrangement on bottom rail; Fig. 14E shows the rack of Fig. 14 in detail; Fig. 14F shows a side view of the rack of Fig. 14E ; Fig. 14G shows a plan view of Fig. 14E ; Fig. 14H shows a view of the rack of Fig. 14E along section line A-A; Fig. 15 shows a yarn guard ; Fig. 15A shows a plan view of Fig. 15 ; Fig. 15B shows a view along arrow X of Fig. 15 ; Figs. 15C, 15D and 15E show views along section lines A-A, B-B and C-C in Fig. 15 ; Figs. 16 and 16A show an auto-drag bobbin carrier according to the present invention in plan and elevation ; Figs. 16B and Fig. 16C show view along section lines A-A and B-B in Fig. 16 ; Fig. 16D shows a side view of Fig. 16A. In the prior art spinning frame schematically shown in Figs. 1 to 4 of the accompanying drawings, jute sliver S (usually made of low quality jute and jute waste) is processed through a heavy yarn system of two-passage drawing and fed from a sliver can through a top conductor T. The sliver is then drawn in by retaining roller R and retaining pressing roller RP to pass through the nip of "V" roller V and "V" pressing roller VP to the nip between bottom roller BR and Bottom pressing roller BP. Rollers V and VP control the drafting of the sliver between rollers R and RP, and between rollers BR and BP. The yarn is then passed over a detector sleeve M which triggers off a mechanical system for stopping the sliver in the event of breakage of the yarn. The drafted material is then drawn through a wharve W to an eye Y located at the bottom end of a two-leg flyer D. Flyer D runs at about 2000 R. P. M. Due to the difference in the speed of flyer D and the speed of bottom roller BR, the yarn is twisted. The twisted yarn is wound on a bobbin P fitted on a bobbin carrier G and spindle E. The spindle E is static and hence is called as "dead spindle". In this system, bobbin rail F of a bobbin rail rack L moves up and down due to up and down movement of lifter brackets LB on which the bobbin rail F sits. The lifter bracket is moved up and down by a cam and lever arrangement. The flyer D which is attached to wharve W, rotates by means driven by a heavy cylinder which in turn is driven directly by an electric motor through an endless belt (not shown). While the wharve W and the flyer D rotate and the bobbin P which sits on bobbin carrier G turns with the pull of the yarn, the spindle E remains stationary. Friction blobs/corck rings control the relative speed of the bobbin carrier G by drag/braking action. The existing 51/2" pitch V Roller Spinning frames are for short-fibre spinning of low quality (waste constituting majority) heavy yarn required for weaving sacks. Its rated operating speed is 2100 R. P. M and requires at least one operator to run a machine. V roller drafting was designed keeping in mind the spinning requirements of short fibres. Generally mills spin Skg. weft yarn between 25 to 34 lbs/spangle with lowest batch. When a mill gets export order for H.Y. of 20-36 lbs, it is spun in the 51/2" V Roller Spinning frame which does not have proper drafting system for 100% long jute which is essential for export quality yarn. As a result the yarn quality is substandard ; but because of plying into Twine (i.e. 29 lbs x 2 ply. etc.) the deficiency is somewhat reduced to a level acceptable to non-critical buyers. The mills have have no option because there is no suitable machine with them. The present invention will hereafter be described with reference to embodiments shown in Figs. 5 to 16D. From Fig. 5, it can be seen that sliver S of 20-80% heavier weight than the existing standard from a finisher passage drawing machine passes between retaining roller R1 and pressing roller BR1 to a lattice gill primary drafting zone A of the spinning frame. The resultant sliver S1 drafted in the primary zone A passes between bottom roller R2 and press roller BR2 and between retaining roller R and press roller RP to enter a secondary drafting zone B of an improved convex apron-tumbler roller control system fitted on a roller stand and rollers. Apron and Tumbler roller control system will be described later. As in prior art, the drafted sliver is drafted by drafting rollers BP, BR as explained with reference to prior art and is passed over a stop motion feeler M which stops the sliver if the yarn breaks. The drafted sliver is passed through an improved wharve W1 into an extra large package cylindrical flyer D1 provided with an air guard D2 (Fig. 6). The wharve will here after be described. As can be seen from Fig. 6, take-up bobbins (P) sit on spindle E1 so that the drag can be varied during building-up of the yarn on the bobbin. Bobbin carriers will be described later. The bobbin carriers having continuously self-adjusting drag control/braking mechanism are rotatably mounted on the spindles which are fixed on the bobbin rails. Lifter brackets K1 of novel construction and improved bobbin rail rack arrangement are provided. These are described later. The wharve W1 is driven by a set of light weight pulleys mounted on a shaft to give individual drive to a pair of wharves. Flyers D for jute spinning are generally of two types - "two leg" D (Fig. 8) or cylindrical (Fig. 9), of steel or aluminium alloy construction. A longer cylindrical flyer D with yarn guard YG (Figs. 15 to 15E) gives increased yarn package and reduces hairiness by shielding yarn from air turbulence of the high speed cylindrical flyer by its yarn guard. In contrast, the existing flyers cause undesired hairiness and are smaller in size and thus give less yarn package. The flyers are fitted through flyer rail FR (Fig. 7) on the hanging bottom end of wharves Wl (Fig. 6) which rotate and in turn rotate the flyers at high speed. The yarn coming out through the central hole of the wharve passes through a central hole at the top of flyer to the eyelet 0 (Fig. 8) located at one of the legs of the 2-leg flyer (D) or one side of the cylindrical flyer Dl (Fig. 9) , which helps twisting of the yarn and winding on the bobbin. The dead spindles E of flyer spinning for jute are fixed on a rail BL (Fig. 7) and the bobbin carriers G (Fig. 6) fit on the dead spindle and again the bobbin P sits on the bobbin carrier G as can be seen from Fig. 10. In other words, the bobbins, bobbin carriers and dead spindles are fitted on a bobbin rail track comprising a set of rails by means of nut N and washer Nl passing through the base N3 of the dead spindle. These rails are called bobbin rails BL. The bobbin rails move up and down for winding the yarn on to the bobbins. There are usually 2 sets of bobbin rails, as a spare ready to take on as soon as the bobbins on the other set is full and doffed. The bobbin rails are of C.I. having 10 to 8 spindle bobbins each and are held in position by means of 2 Nos. of steel pins for easy changing over. The bobbin rails sit on lifter brackets LB which move up and down by cam and lever arrangement. The present invention provides an improved bobbin rail track as shown in Figs. 14 to 14E. The bobbin rail track Rr shifts the position of the rack shaft Rs forward and downward thus increasing the distance between the flyer rail Fr and the rail rack Rr. This enables use of longer cylindrical flyer and thus increase the size of the package. In the prior art bobbin rail rack Bre sits high on the bottom rail Btr (Fig. 14D) and does not allow room for longer flyer to achieve bigger package. Modified bobbin rail rack Rr reduces height "x" (Fig. 14D) to "y" (Fig. 14) , thereby increasing gap between flyer rail FR and bobbin rails BL (Fig. 7) . Wharve Wl is a device to hold the flyer D in a fixed position of the flyer rail FR of a spinning frame and enable the flyer to rotate on its vertical axis (center line) when driven by a tape drive TD from a motor TDM (Fig. 6) through a group drive cylinder CL (Fig. 7). In the existing system of wharve the rotating portion of wharve with flyer is supported by means of two small E15 ball bearings one of which does not have strong support/seat at the bottom side. In the new system, the wharve Wl ensures proper alround support and uses bigger ball bearings etc. so that much bigger flyer for increased yarn package can be fitted thereon and rotated at much higher speed. Fig. 11 shows an improved wharve Wl of the present invention. Two additional larger ball bearings bb in addition to the existing 2 nos. of small E-15 ball bearings B2 with proper supports/seatings S1 & S2 are provided to enable the wharve to take higher load of a bigger cylindrical flyer which is fitted at the end WE of the wharve. Also, in this arrangement, an outer case OC is fitted on bearing bb and is supported by top and bottom flanges Tf and Bf for achieving higher flyer speed of bigger flyer. The top end of the wharve Wl is mounted to the flyer rail FR with ring nuts RN. The bottom flange Bf is fitted with a yarn tube YT and screwed to a bottom cap BC. The yarn tube extends through the wharve Wl and the flyer rail FR. The wharve of prior art with only 2 nos. of E-15 ball bearing is not good enough for running bigger flyer at higher speed. The wharve Wl of the present invention overcomes this problem. The yarn passes through the central hole of the wharve in both the systems and then exits through either a yarn tube or whole of the flyer (D) or (Dl) , goes to the bottom eyelet (0) of the flyer and warps round the bobbin (P) as can be seen from Fig. 7. When the spinning frame is to be used for a wider range, i.e. L.Y. version, the live spindles El (Fig. 6) are driven by a tangential belt connected to a motor. In this case, bobbin carriers El can be eliminated. Spindle and wharve brake may be added as an optional feature. Figs. 12 to 12C show an improved arrangement of live spindles. Live spindle S is fixed on the bobbin rail BL by means of a flanged bearing housing h and is driven by a tangential tape through a pulley SP fitted on the spindles. There is a brake drum d and braking device BK to stop the spindle when required. The spindle speed can be varied or adjusted in relation with the flyer speed to achieve right control of drag particularly for sensitive yarn count and fibre mix by adjusting speed of motor or by changing wheels of the drive from the motor. In the existing system the spindle is a "dead" spindle i.e., static/fixed, and bobbin carrier, which fits on the dead spindle, rotates on the dead spindle by the pull of the yarn caused by flyer rotation. If the bobbin rotates more due to less drag, the yarn brakes and if the bobbin rotates less due to excessive drag, then also the yarn breaks. This problem is resolved by maintaining proper speed of spindle where bobbin carriers are not required. The speed of the live spindle can be controlled by varying the speed of the motor TDM which drives the tangential tape drive mechanism TD (Fig. 6). The present invention permits introduction of apron and tumbler roller assembly in the secondary drafting zone on existing roller stands without any alteration or machining of existing rollers. Apron and tumbler roller on convex apron plate (Figs. 10A-10G) comprises a convex apron plate AP which has an apron plate roller (r, r1) at each end ; the top roller r is slightly bigger in diameter than the bottom apron plate roller r1. The apron plate AP has two grooves g on the sliver path (Fig. 10B). An endless rubber apron RA is fitted on the apron plate AP in the manner shown in Fig. 10A. Tumbler rollers TR are rotatably mounted on the rubber apron AP so that, when the apron moves, the tumbler rollers rotate. A jocky roller J is used for tensioning of the rubber apron RA. The apron plate AP enclosed in rubber apron rests on a knurrled apron driving roller AR which drives the rubber apron by friction. This helps to improve control on inter fibre movement/alignment and replaces the old "V" roller drafting system which had a very limited control and was unsatisfactory for long jute good quality yarn spinning quality. Also old system has limitation of yarn count to heavy side only. The apron end tumbler roller assembly of this invention fits between two horn brackets H (Fig. 10B) . This also allows retention and use of existing stop motion system (Fig. 10G) . From Fig. 10B it can be seen that two horn brackets H are spaced apart from each other. Each bracket is provided with grooves gl in which pins P1 for apron plate are received. The brackets are also provided with grooves g2 for receiving pins P2 of the tumbler rollers (TR) . The brackets are also provided with tapered pin holes PH at the top end and rubber pressing roller seats PS at the bottom end for mounting of the brackets. Fig. 10G shows the apron and tumbler roller assembly of Fig. 10B fitting between the outside faces of two horn brackets H1 and H2. The present invention also provides for retaining existing stop motion system. The present invention also envisages incorporation of a lattice gill primary drafting envisages incorporation of a lattice gill primary drafting zone on existing machine. The bobbin rail rack arrangement is relocated and modified to increase package size to atleast 70% more. The present invention also includes an improved lifter bracket and an auto-drag bobbin carrier. Live spindle and drive arrangement and spindle brake mechanism can be provided in the existing machine. The existing lifter bracket has two oilite bushes at each end of the bracket, which get jammed against the slide rod and badly misalign the bobbin rails. To clear the jam and to bring the rails in line, the operators have to use crow-bar, hammer etc causing not only down time but also maintenance problem, as frequent as after each cycle of 30-50 mt. The lifter bracket of the present invention overcomes this problem. The improved lifter bracket Kl (Figs. 13-13F), has 8 nos. of ball bearings bbl - 4 nos. at top and 4 nos. at the bottom part of the lifter bracket Kl. The position of these bearings is slightly adjustable to ensure proper contact with the slide rod Sd from all four directions. These bearings help ensure smooth jam-free up and down movement of the lifter brackets and the bobbin rails BL (Fig. 6) which sit on the lifter brackets. This greatly reduces doffing time loss and maintenance, and increases spinning output. Auto-drag bobbin carrier (Figs. 16 to 16D) has the ability to control drag through out the building of the bobbin i.e., throughout the yarn winding process on the both carriers. This is very important to adjust the amount of drag as the yarn winds on the bobbin and the bobbin weight increases. In the existing bobbin carriers, the drag is fixed and remains same irrespective of the increase in weight of bobbin due to increasing yarn wound on the bobbin. This causes increased yarn breakage rate at the beginning and towards the end of bobbin building, i.e., at the start of the spinning and near the doffing time, or in other words, when the yarn package diameter is small and when the yarn package diameter is big. This also results in high down time required to mend the high number of broken ends at the doffing time. The autodrag bobbin carrier of the present invention minimises this problem and reduces yarn breakage rate. The autodrag bobbin carrier C of Figs. 16-16D has one set of spring-loaded inner nylon blobs N which adjusts in keeping with the weight of yarn built on the bobbin and a set of outer felt blobs CF. At certain point towards the end of the building period when the bobbin weight increases and exceeds the compression load of the springs of the blobs N, the nylon blobs come level with felt blobs CF which then start imparting necessary increased drag, thus ensuring different/proper drag at different points of the yarn building on the bobbin. Existing cylinder drive can be replaced by individual light weight pulley drive. The present invention has the following advantages over prior art: a) The operating flyer speed will be almost double that of the existing machine. b) The upgraded machine can spin 8 pounds to 40 pounds per spangle jute yarn for both Hessian and sacking. c) This will give the industry proper heavy yarn spinning machine for meeting adequately export yarn parameters of heavy yarn. d) The yarn package will be almost double. As a result light yarn package can go straight to the Beaming machine creel, thereby cutting down the process of roll winding. e) The drag control will be more precise and variable during the build in the running machine. Two-zone drafting will ensure proper fibre control and drafting. f) It will be possible to operate two machines of 80 spindles each by one operator which means half the labour cost. A comparative study is set out to give feature by feature comparison between prior art machine and the improved machine of the present invention. I CLAIM : 1. A silver spinning frame comprising : a lattice gill primary drafting zone (A) fitted on the top of said spinning frame ; a secondary drafting zone (B) fitted between two horn brackets (H) of said spinning frame ; a wharve (W1) ; a large package cylindrical flyer (D1) having an air guard (D2) and connected to said wharve ; take-up bobbins (R) mounted on bobbin carriers (G), said bobbin carriers having a self-adjusting drag control/braking mechanism for controlling the speed of the bobbin relative to the weight of the yarn wound on the bobbin, said bobbins sitting on spindles (E1) and being rotable by the pull of the yarn imparted by the rotation of the flyer ; friction-free reinforced lifter brackets (K1) for supporting and guiding the up and down movement of the bobbin rails (BL) of a bobbin rail rack (Rr) said spindles, bobbins and bobbin carriers fitting within the bobbin rail rack, said brackets supporting a tangential drive (TD) for said spindles, and each bobbin rail having a gear and driving arrangement engageable with said tangential drive. 2. Sliver spinning frame as claimed in claim 1, wherein said spindle is a dead spindle (E) mounted on said bobbin rails (BL), said bobbin carrier (G) is fitted on said spindle (E), said bobbin (P) sitting on said bobbin carrier (G). 3. Sliver spinning frame as claimed in claim 2, wherein said dead spindles are fitted on said bobbin rails by means of a nut (N) and a washer (Nl) passing through the base (N3) of each said spindle. 4. Sliver spinning frame as claimed in claim 1, wherein said spindles are live spindles (S) driven by a tangential belt and a motor drive, said live spindles being fixed on said bobbin rials (BL) of the bobbin rail track, there being a braking device (BK) for stopping the spindle when required. 5. Sliver spinning frame as claimed in any of claims 1 to 4, wherein said secondary drafting zone is provided with an apron and tumbler assembly comprising : a convex apron plate (AP) provided with an apron plate roller (r, r1) at each end, and two grooves (g) on the sliver path ; an endless rubber apron (RA) fitted on said apron plate (AP), said apron passing over a jockey roller (J) to enable tensioning of said apron ; a driving roller (AR) for drivingly supporting said apron plate (AP) ; and tumbler rollers (TR) mounted on said apron plate (AP). 6. Sliver spinning frame as claimed in claim 5, wherein said apron and tumbler roller assembly is mounted between a pair of said horn brackets (H), each said bracket having grooves (g1) for receiving the pins (P1) of said apron plate (AP), and grooves (g2) for receiving pins (P2) of said tumbler rollers (TR). 7. Sliver spinning frame as claimed in any of claims 2, 3, 5 and 6, wherein said bobbin carrier comprises an auto-drag bobbin carrier (C) provided with inner spring-loaded nylon blobs (N) and outer felt blobs (CF). 8. Sliver spinning frame as claimed in any preceding claim, wherein said lifter bracket (K1) is mounted on ball bearings (bb1) provided at its top and bottom ends, said bobbin rails (BL) sitting on said lifter brackets. 9. Sliver spinning frame as claimed in any preceding claim, wherein said wharve comprises an outer case (OC) fitted in bearings (bb and B2), a yarn tube (YT) passing centrally through a bottom cap (BC) at one end of said outer case and having its other end passing through said flyer rail (FR) ; and a top flange (Tf) fitted to the other end of said outer case, said wharve being mounted on said flyer rail (FR). 10. Sliver spinning frame as claimed in any preceding claim, wherein said bobbin rail rack (Rr) supports a rack shaft (Rs) for shifting the position of said rack shaft forward and downward to increase the distance between said flyer (D) and said rail rack (Rr). 11. Apron and tumbler roller assembly for a sliver spinning frame as claimed in any of the preceding claims, said apron and tumbler roller assembly comprising : a convex apron plate (AP) provided with an apron plate roller (r, r1) at each end, and two grooves (g) on the sliver path ; an endless rubber apron (RA) fitted on said apron plate (AP), said apron passing over a jockey roller (J) to enable tensioning of said apron ; a driving roller (AR) for drivingly supporting said apron plate (AP); and tumbler rollers (TR) mounted on said apron plate (AP). 12. Apron and tumbler roller assembly as claimed in claim 11, wherein said assembly is mounted between a pair of horn brackets (H), each said bracket having grooves (g1) for receiving the pins (P1) of said apron plate (AP), and grooves (g2) for receiving pins (P2) of said tumbler rollers (TR). 13. An auto-drag bobbin carrier for a sliver spinning frame as claimed in claims 1 to 10, said auto-drag bobbin carrier comprising a bobbin carrier provided with inner spring-loaded nylon blobs (N) and outer felt blobs (CF). 14. A wharve for a sliver spinning frame as claimed in claims 1 to 10, said wharve comprising : an outer case (OC) fitted in bearings (bb and B2), a yarn tube (YT) passing centrally through a bottom cap (BC) at one end of said outer case and having its other end passing through a flyer rail (FR); a top flange (Tf) fitted to the other end of said outer case, said wharve being mounted on said flyer rail (FR). 15. Live spindle for a sliver spinning frame as claimed in claims 1 to 10, said spindle comprising : a spindle (S) fixed on a bobbin rail (BL) by means of a flanged bearing housing (h), a tangential tape with pulley for driving said spindle ; and a brake drum (d) and brake device for stopping the motion of said spindle. 16. A bobbin rail rack for a sliver spinning frame as claimed in claims 1 to 10, wherein said rack (Rr) is mounted on a bottom rail (Btr) and rack shaft (Rs) is provided, so that by movement of said rack, the position of the rack shaft is shiftable forward and downward. 17. A sliver spinning frame, substantially as herein described, particularly with reference to and as illustrated in the accompanying drawings. A silver spinning frame comprises : a lattice gill primary drafting zone (A) fitted on the top of said spinning frame ; and a secondary drafting zone (B) fitted between two horn brackets (H) of said spinning frame ; a wharve (W1) connected to a large package cylindrical flyer (D1) having an air guard (D2) ; take-up bobbins (R) mounted on bobbin carriers (G), having a self-adjusting drag control/braking mechanism for controlling the speed of the bobbin relative to the weight of the yarn wound on the bobbin, said bobbins sitting on spindles (E1) and being ratable by the pull of the yarn imparted by the rotation of the flyer; friction-free reinforced lifter brackets (K1) for supporting and guiding the up and down movement of the bobbin rails (BL) of a bobbin rail rack (Rr) said spindles, bobbins and bobbin carriers fitting within the bobbin rail rack, said brackets supporting a tangential drive (TD) for said spindles, and each bobbin rail having a gear and driving arrangement engageable with said tangential drive.

Documents:

02161-cal-1997-abstract.pdf

02161-cal-1997-claims.pdf

02161-cal-1997-correspondence.pdf

02161-cal-1997-description (complete).pdf

02161-cal-1997-description (provisional).pdf

02161-cal-1997-drawings.pdf

02161-cal-1997-form 1.pdf

02161-cal-1997-form 2.pdf

02161-cal-1997-form 3.pdf

02161-cal-1997-form 5.pdf

02161-cal-1997-letter patent.pdf

02161-cal-1997-pa.pdf

02161-cal-1997-reply f.e.r.pdf