TENSION LET OFF DEVICE FOR A KNITTING MACHINE
United States Patent 3793852
The device pertains to a knitting machine for knitting a plurality of narrow elastic tapes using elastic yarn. It comprises a rectangular supporting frame on vertical legs so that the frame straddles a plurality of rows of roving cans or bins. A pair of vertically contiguous rollers are mounted on the frame extending across each row of cans. The rollers in each pair are provided with meshing gears at one end so that they rotate in opposite directions. The lower roller of each pair is connected by a sprocket chain with the lower roller of the adjacent pair so that a single drive will drive all the rollers. A single upper roller at the front of the frame forms the drive for the other rollers. The knitted tapes leave the knitting machine at the bottom under tension and pass around a driven roller which is driven from the knitting machine drive. This roller is connected by a sprocket chain to a lower roller at the front of the frame which it drives at the same speed. The lower roller is connected by a sprocket chain to the front upper roller with a reduced gear drive which cuts the speed of the upper roller to half the speed of the lower roller. All the frame rollers, driven from the front upper roller operate at this reduced speed. The knitted tape passes around the lower front roller and up to the upper front roller. Then around this and through the pairs of rollers on the frame. Tension on the tapes is reduced by half at the upper front roller due to the reduced speed. As each tape reaches a predetermined roving can, it is directed downwardly from the rollers, releasing the remaining tension. Each tape passes through one or more pairs of rollers on the frame until its can is reached.
US Patent References:
Picking motion for a loom
Ross - November 1956 - 2771098
Chenille-strip distribution
Hathaway - October 1921 - 1392939
Apparatus for moving tow
Smith - November 1963 - 3110432
APPARATUS FOR TREATING THERMOPLASTIC FABRIC DURING WEAVING
Herkenberg - June 1970 - 3515174
Apparatus for coiling wool sliver in cans
Wilkie - June 1952 - 2598738
Picking motion for a loom
Ross - November 1956 - 2771098
Chenille-strip distribution
Hathaway - October 1921 - 1392939
Apparatus for moving tow
Smith - November 1963 - 3110432
APPARATUS FOR TREATING THERMOPLASTIC FABRIC DURING WEAVING
Herkenberg - June 1970 - 3515174
Apparatus for coiling wool sliver in cans
Wilkie - June 1952 - 2598738
Application Number:
05/256430
Publication Date:
02/26/1974
Filing Date:
05/24/1972
View Patent Images:
Export Citation:
Assignee:
Atlas Braid Company (Cumberland, RI)
Primary Class:
Other Classes:
139/304
International Classes:
D04B15/38; D04B15/88
Field of Search:
66/152,149R 139/291R,291C,304,307 28/1CS 19/159R
US Patent References:
| 3522715 | CIRCULAR WARP KNITTING MACHINE | August 1970 | Merritt et al. |
Primary Examiner:
Reynolds W. C.
Assistant Examiner:
Falik A. M.
Attorney, Agent or Firm:
Schwartz, Max
Claims:
I claim
1. A tension let off for a knitting machine for knitting a plurality of narrow elastic tapes under tension, comprising a rectangular frame, a vertical leg at each corner of said frame supporting said frame in raised position, a plurality of open top containers beneath said frame in aligned rows, one container for each tape issuing under tension from the knitting machine, means for passing the tapes under tension from the knitting machine to said frame, means on said frame for reducing the tension on the tapes, and means on said frame for distributing the tapes to their respective containers and for releasing the tension on the tapes, said means being driven from the knitting machine drive.
2. A tension let off device as in claim 1, wherein said passing means comprises a driven roller at the lower rear of the knitting machine and a roller at the lower front of said frame, drive means from said machine roller to said frame roller, said tapes passing under tension around said machine roller and to and around said frame roller, and said tension reducing means includes a roller mounted at the upper front of said frame, said upper roller being driven from said lower frame roller at half the speed thereof, said tapes passing from around said lower frame roller upwardly and over the said upper roller to reduce the tension by half.
3. A tension let off device as in claim 1, wherein said distributing means includes a pair of vertically contiguous rollers mounted transversely in said frame above each row of containers, the lower of each of said rollers being driven, each tape passing under tension between at least one pair of rollers then down into the respective container to release the tension.
4. A tension let off device as in claim 1, wherein said means are driven by gear and sprocket chains from the knitting machine to the tape passing means, then from the tape passing means to said reducing means, and finally from said tension reducing means to said distributing means.
5. A tension let off device as in claim 2, wherein said distributing means includes a pair of vertically contiguous rollers mounted transversely in said frame above each row of containers, the lower of each of said rollers being driven, each tape passing under tension between at least one pair of rollers then down into the respective container to release the tension.
6. A tension let off device as in claim 2, wherein said means are driven by gear and sprocket chains from the knitting machine to the tape passing means, then from the tape passing means to said reducing means, and finally from said tension reducing means to said distributing means.
7. A tension let off device as in claim 3, wherein said means are driven by gear and sprocket chains from the knitting machine to the tape passing means, then from the tape passing means to said reducing means, and finally from said tension reducing means to said distributing means.
8. A tension let off device as in claim 5, wherein said means are driven by gear and sprocket chains from the knitting machine to the tape passing means, then from the tape passing means to said reducing means, and finally from said tension reducing means to said distributing means.
1. A tension let off for a knitting machine for knitting a plurality of narrow elastic tapes under tension, comprising a rectangular frame, a vertical leg at each corner of said frame supporting said frame in raised position, a plurality of open top containers beneath said frame in aligned rows, one container for each tape issuing under tension from the knitting machine, means for passing the tapes under tension from the knitting machine to said frame, means on said frame for reducing the tension on the tapes, and means on said frame for distributing the tapes to their respective containers and for releasing the tension on the tapes, said means being driven from the knitting machine drive.
2. A tension let off device as in claim 1, wherein said passing means comprises a driven roller at the lower rear of the knitting machine and a roller at the lower front of said frame, drive means from said machine roller to said frame roller, said tapes passing under tension around said machine roller and to and around said frame roller, and said tension reducing means includes a roller mounted at the upper front of said frame, said upper roller being driven from said lower frame roller at half the speed thereof, said tapes passing from around said lower frame roller upwardly and over the said upper roller to reduce the tension by half.
3. A tension let off device as in claim 1, wherein said distributing means includes a pair of vertically contiguous rollers mounted transversely in said frame above each row of containers, the lower of each of said rollers being driven, each tape passing under tension between at least one pair of rollers then down into the respective container to release the tension.
4. A tension let off device as in claim 1, wherein said means are driven by gear and sprocket chains from the knitting machine to the tape passing means, then from the tape passing means to said reducing means, and finally from said tension reducing means to said distributing means.
5. A tension let off device as in claim 2, wherein said distributing means includes a pair of vertically contiguous rollers mounted transversely in said frame above each row of containers, the lower of each of said rollers being driven, each tape passing under tension between at least one pair of rollers then down into the respective container to release the tension.
6. A tension let off device as in claim 2, wherein said means are driven by gear and sprocket chains from the knitting machine to the tape passing means, then from the tape passing means to said reducing means, and finally from said tension reducing means to said distributing means.
7. A tension let off device as in claim 3, wherein said means are driven by gear and sprocket chains from the knitting machine to the tape passing means, then from the tape passing means to said reducing means, and finally from said tension reducing means to said distributing means.
8. A tension let off device as in claim 5, wherein said means are driven by gear and sprocket chains from the knitting machine to the tape passing means, then from the tape passing means to said reducing means, and finally from said tension reducing means to said distributing means.
Description:
BACKGROUND OF THE INVENTION
When elastic yarn is knitted into a narrow elastic tape, a modern high speed knitting machine is used which can knit approximately 40 tapes simultaneously. For efficient operation of such a knitting machine, it is essential that the yarn be maintained under a suitable tension at all times. The elastic yarn is therefore fed to the machine under tension, using a yarn frame with a suitable tensioning device for each spool of yarn. When the tape is finished, the tension is released. However, applicant has found that the released tension has a tendency to back into the knitting machine even though the tapes are drawn from the machine by a driven polished steel roller. The tapes will slip on the polished steel roll to some extent to relax the tension in the knitting machine. Since this relaxation of the tension is not uniform, the smooth and efficient operation of the knitting machine is upset, causing broken ends, stoppages, etc.
SUMMARY OF THE INVENTION
The present invention provides a let off device which maintains the tension on the finished tape to the final point of release into its receiving can or bin. This maintains the tension in the knitting machine at the let off end. The device passes the finished tapes around a series of driven rolls which first reduce the tension approximately by half. Then the tapes are passed between pairs of pinching rolls which positively hold each tape under tension. Each tape passes from a pair of pinching rolls to a roving can or other receptacle, releasing the tension. The device is simple, a supporting frame straddles a plurality of rows of roving cans. The frame supports a pair of pinching rolls extending across each row of cans. The tapes pass from the knitting machine to a lower and then to an upper roller at the front of the frame. The lower roller is driven from the knitting machine roller. The upper roller is driven from the lower roller but the speed is cut in two. The pinching rollers are driven from the upper roller at the reduced speed. The tapes pass from the upper roller, at half the tension, through the pinching rollers and into their respective roving cans or bins. Thus the let off tension at the knitting machine is constantly maintained, the relaxed tension at each can being confined to the exit from between the pinching rollers.
DESCRIPTION OF DRAWINGS.
FIG. 1 is a side elevation of a let off device embodying my present invention;
FIG. 2 is a top plan view thereof, partially broken away;
FIG. 3 is a front elevation thereof;
FIG. 4 is a side elevation of the drive take-off from the knitting machine;
FIG. 5 is a side elevation of one of the yarn tensioning elements; and
FIG. 6 is a top plan view of one of the yarn tensioning devices.
DESCRIPTION OF THE INVENTION.
Referring more in detail to the drawings, FIGS. 1, 2 and 3 illustrate the device of the present invention. A rectangular frame is formed of angle iron or other suitable material, comprising side bars 10, a front bar 11 and a rear bar 12. The frame is supported on vertical legs 13 at each corner. In the illustrated form, it is assumed that the knitting machine is making 40 elastic tapes, and the device is provided with 40 roving cans 14 positioned beneath the frame in 4 rows of 10 to a row, each can 14 receiving one of the tapes.
Tension on the tapes is maintained by passing the tapes around and between a series of driven rollers so that the let off of the tension is postponed until the very last moment. Referring to FIG. 4, the back of the knitting machine 15 is provided at its base 16 with a gear 17 which is driven counterclockwise by the sprocket chain 18 from the knitting machine drive (not shown). Mounted on the base 16, in front of the gear 17, is a roller having a gear 19 at one end which meshes with the gear 17 to drive the roller counterclockwise. The tapes 20 leave the knitting machine under tension and pass around and under the roller driven at the speed of exit of the tapes. From this point the tapes 20 pass under the platform 21 at the front of the machine 15, see FIG. 1, and into the device of the present invention.
Positioned on the floor in front of the device is an elongated strip 22 having a plurality of vertical spaced guide pins 23, the tapes 20 passing between the guide pins 23. Mounted at the lower front portion of the device is a shaft 24 having a roller 25 adjacent the center, the tapes 20 passing from the guide pins 23 down and around the roller 25 and then upwardly. Just below the upper surface of the frame, a roller 26 is mounted above the roller 25, but extending across the entire front of the frame, see FIG. 3.
The drive of the rollers 25 and 26 is shown in FIGS. 1, 3 and 4. The shaft 24 carrying the roller 25 is driven through a sprocket chain 27 from the roller gear 19. All gear sizes being equal, the roller 25 is rotating at the same surface speed as the roller at the back of the machine 15 so that the tapes 20 maintain their tension up to and around the roller 25, and to the roller 26. Now viewing FIGS. 1 and 3, one end of the shaft 24 is provided with a gear 28 which meshes with a gear 29 mounted on the vertical leg 13 directly above it. The gear 29 has a small gear 30 which drives a sprocket chain 31. The chain 31 passes around a gear 32 mounted at the end of the roller 26 shaft. Note that the gear 32 is twice the diameter of the gear 30 to reduce the rotation of the roller 26 to one half the speed of the roller 25. The tapes 20 thus leave the roller 26 at half the tension.
Now viewing FIGS. 1, 2 and 3, a lower driven roller is journalled in the side bars 10 above each row of cans 14, at 33. On top of the side bars 10, above each point 33, is a bearing 34 with a U-shaped open slot. An upper roller 35 is provided with a shaft 36 which enters each slot loosely, so that the upper shafts 36 will allow the rollers 35 to rest on the lower rollers which are journalled and supported at 33.
One end of the roller 26 shaft is provided with a gear 37 which drives a chain 38 which drives the nearest lower shaft 33, see FIGS. 1 and 2. Now this shaft 33 drives the adjacent one through a chain drive 39, which drives the next one through the chain 40, and finally the last one through the chain 41.
Now as can be seen in FIGS. 2 and 3, the tapes 20 pass around the upper front roller 26 through a plurality of distributing guide pins 42. A group of pins 42 are mounted on the front cross bar 11 in front of each row of cans 14. With 4 cans in a row, 4 tapes 20 enter each group of pins 42. Now as can be seen in FIG. 2, the 4 tapes all pass between the first set of rollers and one of the tapes is then directed down into the nearest can 14 with its tension released. The other 3 tapes now pass through the next set of rollers and another tape enters the next can. The last 2 tapes now pass through the next rollers with one tape dropping, leaving the last tape for the last set of rollers and the last can. This is repeated at each group of pins for each row of cans.
While I have illustrated the use of roving cans 14, any suitable bin or container can be used. For example, a container on wheels can be used for easier removal of a full container and quick replacement with an empty one. The device thus post-pones the release of the tension on each tape until the moment of release into the receiving container. Furthermore, each tape is being held between pinching rollers so that the released tension does not work back into the knitting machine.
While any suitable tensioning means can be used for feeding the yarn to the knitting machine, I have found that best results are obtained with the type shown in FIGS. 4, 5 and 6. The yarn frame 43 is provided with a horizontal bar 44 in front of each spool of yarn 45. A strip of metal 46 is mounted on the bar 44 with its inner end, adjacent the spool, bent up at 47. The strip is mounted on the bar 44 by an elongated screw 48 on which a ceramic cylinder 49 is loosely positioned. At the outer end of the strip 46, an elongated screw 50 provides a support for a similar ceramic cylinder 51. Opposed plates 52 are loosely mounted on the cylinder 51 and a plurality of washers 53 are mounted over the plates 52.
A short distance along the bar 44, in a direction toward the knitting machine, another elongated screw 54 is provided with a loose ceramic cylinder 55 and a plate and washer arrangement 56 such as the plates and washers 52 and 53. The yarn 57 passes through an eyelet 58 in the vertical portion 47, see FIG. 6. The yarn 57 now passes around the cylinder 49, across and around the cylinder 55 between the plates 56, back to the cylinder 51 between the plates 52, then back to the knitting machine. The various turns made by the yarn, plus the pressure between the plates, causes a frictional drag to create a tension on the yarn. This tension can be controlled and varied by changing the number of washers at 53 and 56 which exert the pressure on the plates and the yarn.
The device of the present invention is therefore simple in construction and easy and economical to manufacture and assemble. The knitting machine runs rapidly and smoothly with a uniform yarn tension both at entry and let off. Other advantages of the present invention will be readily apparent to a person skilled in the art.
When elastic yarn is knitted into a narrow elastic tape, a modern high speed knitting machine is used which can knit approximately 40 tapes simultaneously. For efficient operation of such a knitting machine, it is essential that the yarn be maintained under a suitable tension at all times. The elastic yarn is therefore fed to the machine under tension, using a yarn frame with a suitable tensioning device for each spool of yarn. When the tape is finished, the tension is released. However, applicant has found that the released tension has a tendency to back into the knitting machine even though the tapes are drawn from the machine by a driven polished steel roller. The tapes will slip on the polished steel roll to some extent to relax the tension in the knitting machine. Since this relaxation of the tension is not uniform, the smooth and efficient operation of the knitting machine is upset, causing broken ends, stoppages, etc.
SUMMARY OF THE INVENTION
The present invention provides a let off device which maintains the tension on the finished tape to the final point of release into its receiving can or bin. This maintains the tension in the knitting machine at the let off end. The device passes the finished tapes around a series of driven rolls which first reduce the tension approximately by half. Then the tapes are passed between pairs of pinching rolls which positively hold each tape under tension. Each tape passes from a pair of pinching rolls to a roving can or other receptacle, releasing the tension. The device is simple, a supporting frame straddles a plurality of rows of roving cans. The frame supports a pair of pinching rolls extending across each row of cans. The tapes pass from the knitting machine to a lower and then to an upper roller at the front of the frame. The lower roller is driven from the knitting machine roller. The upper roller is driven from the lower roller but the speed is cut in two. The pinching rollers are driven from the upper roller at the reduced speed. The tapes pass from the upper roller, at half the tension, through the pinching rollers and into their respective roving cans or bins. Thus the let off tension at the knitting machine is constantly maintained, the relaxed tension at each can being confined to the exit from between the pinching rollers.
DESCRIPTION OF DRAWINGS.
FIG. 1 is a side elevation of a let off device embodying my present invention;
FIG. 2 is a top plan view thereof, partially broken away;
FIG. 3 is a front elevation thereof;
FIG. 4 is a side elevation of the drive take-off from the knitting machine;
FIG. 5 is a side elevation of one of the yarn tensioning elements; and
FIG. 6 is a top plan view of one of the yarn tensioning devices.
DESCRIPTION OF THE INVENTION.
Referring more in detail to the drawings, FIGS. 1, 2 and 3 illustrate the device of the present invention. A rectangular frame is formed of angle iron or other suitable material, comprising side bars 10, a front bar 11 and a rear bar 12. The frame is supported on vertical legs 13 at each corner. In the illustrated form, it is assumed that the knitting machine is making 40 elastic tapes, and the device is provided with 40 roving cans 14 positioned beneath the frame in 4 rows of 10 to a row, each can 14 receiving one of the tapes.
Tension on the tapes is maintained by passing the tapes around and between a series of driven rollers so that the let off of the tension is postponed until the very last moment. Referring to FIG. 4, the back of the knitting machine 15 is provided at its base 16 with a gear 17 which is driven counterclockwise by the sprocket chain 18 from the knitting machine drive (not shown). Mounted on the base 16, in front of the gear 17, is a roller having a gear 19 at one end which meshes with the gear 17 to drive the roller counterclockwise. The tapes 20 leave the knitting machine under tension and pass around and under the roller driven at the speed of exit of the tapes. From this point the tapes 20 pass under the platform 21 at the front of the machine 15, see FIG. 1, and into the device of the present invention.
Positioned on the floor in front of the device is an elongated strip 22 having a plurality of vertical spaced guide pins 23, the tapes 20 passing between the guide pins 23. Mounted at the lower front portion of the device is a shaft 24 having a roller 25 adjacent the center, the tapes 20 passing from the guide pins 23 down and around the roller 25 and then upwardly. Just below the upper surface of the frame, a roller 26 is mounted above the roller 25, but extending across the entire front of the frame, see FIG. 3.
The drive of the rollers 25 and 26 is shown in FIGS. 1, 3 and 4. The shaft 24 carrying the roller 25 is driven through a sprocket chain 27 from the roller gear 19. All gear sizes being equal, the roller 25 is rotating at the same surface speed as the roller at the back of the machine 15 so that the tapes 20 maintain their tension up to and around the roller 25, and to the roller 26. Now viewing FIGS. 1 and 3, one end of the shaft 24 is provided with a gear 28 which meshes with a gear 29 mounted on the vertical leg 13 directly above it. The gear 29 has a small gear 30 which drives a sprocket chain 31. The chain 31 passes around a gear 32 mounted at the end of the roller 26 shaft. Note that the gear 32 is twice the diameter of the gear 30 to reduce the rotation of the roller 26 to one half the speed of the roller 25. The tapes 20 thus leave the roller 26 at half the tension.
Now viewing FIGS. 1, 2 and 3, a lower driven roller is journalled in the side bars 10 above each row of cans 14, at 33. On top of the side bars 10, above each point 33, is a bearing 34 with a U-shaped open slot. An upper roller 35 is provided with a shaft 36 which enters each slot loosely, so that the upper shafts 36 will allow the rollers 35 to rest on the lower rollers which are journalled and supported at 33.
One end of the roller 26 shaft is provided with a gear 37 which drives a chain 38 which drives the nearest lower shaft 33, see FIGS. 1 and 2. Now this shaft 33 drives the adjacent one through a chain drive 39, which drives the next one through the chain 40, and finally the last one through the chain 41.
Now as can be seen in FIGS. 2 and 3, the tapes 20 pass around the upper front roller 26 through a plurality of distributing guide pins 42. A group of pins 42 are mounted on the front cross bar 11 in front of each row of cans 14. With 4 cans in a row, 4 tapes 20 enter each group of pins 42. Now as can be seen in FIG. 2, the 4 tapes all pass between the first set of rollers and one of the tapes is then directed down into the nearest can 14 with its tension released. The other 3 tapes now pass through the next set of rollers and another tape enters the next can. The last 2 tapes now pass through the next rollers with one tape dropping, leaving the last tape for the last set of rollers and the last can. This is repeated at each group of pins for each row of cans.
While I have illustrated the use of roving cans 14, any suitable bin or container can be used. For example, a container on wheels can be used for easier removal of a full container and quick replacement with an empty one. The device thus post-pones the release of the tension on each tape until the moment of release into the receiving container. Furthermore, each tape is being held between pinching rollers so that the released tension does not work back into the knitting machine.
While any suitable tensioning means can be used for feeding the yarn to the knitting machine, I have found that best results are obtained with the type shown in FIGS. 4, 5 and 6. The yarn frame 43 is provided with a horizontal bar 44 in front of each spool of yarn 45. A strip of metal 46 is mounted on the bar 44 with its inner end, adjacent the spool, bent up at 47. The strip is mounted on the bar 44 by an elongated screw 48 on which a ceramic cylinder 49 is loosely positioned. At the outer end of the strip 46, an elongated screw 50 provides a support for a similar ceramic cylinder 51. Opposed plates 52 are loosely mounted on the cylinder 51 and a plurality of washers 53 are mounted over the plates 52.
A short distance along the bar 44, in a direction toward the knitting machine, another elongated screw 54 is provided with a loose ceramic cylinder 55 and a plate and washer arrangement 56 such as the plates and washers 52 and 53. The yarn 57 passes through an eyelet 58 in the vertical portion 47, see FIG. 6. The yarn 57 now passes around the cylinder 49, across and around the cylinder 55 between the plates 56, back to the cylinder 51 between the plates 52, then back to the knitting machine. The various turns made by the yarn, plus the pressure between the plates, causes a frictional drag to create a tension on the yarn. This tension can be controlled and varied by changing the number of washers at 53 and 56 which exert the pressure on the plates and the yarn.
The device of the present invention is therefore simple in construction and easy and economical to manufacture and assemble. The knitting machine runs rapidly and smoothly with a uniform yarn tension both at entry and let off. Other advantages of the present invention will be readily apparent to a person skilled in the art.