US3028738A - Apparatus for continuous and automatic adjustment and control of the stitch length or closeness of loops during operation of knitting and stockings machines - Google Patents

Description

April 10, 1962 K. I. J. ROSEN 3, 3

APPARATUS FOR. CONTINUOUS AND AUTOMATIC ADJUSTMENT AND CONTROL Aprll 10, 1962 K. I. J. ROSEN 3,028,738

APPARATUS FOR CONTINUOUS AND AUTOMATIC ADJUSTMENT AND CONTROL OF THE STITCH LENGTH OR CLOSENESS 0F LOOPS DURING OPERATION OF KNITTING AND STOCKINGS MACHINES Filed March 30-, 1959 2 Sheets-Sheet 2 Fig. 2 5

VII/ll/l/IIIII/A I 0 7 17 \26 j K l 5 34 g I I961 31 78 26a 1 12 27 i I 22 a I 23 E 25 2 l 1% 73 E 33 g .f 30/ V K v INVENTOR. Km I/I ROSEN APPARATUS FOR CONTINUOUS AND AUTO- MATIC ADJUSTMENT AND CONTROL OF THE STITCH LENGTH R CLOSENESS 0F LOGPS DURING OPERATION OF KNITTING AND STOCKINGS MACHINES Karl Isac .loel Rosn, Villa Haga, Ulricehamn, Sweden Filed Mar. 30, 1959, Ser. No. 802,735 3 Claims. (Cl. 66-54) This invention relates to an apparatus for automatic and continuous control of the stitch length or closeness of the loops during operation of tricot or stocking knitting machines.

In the manufacture of fabrics on for instance interlock and rib machines it is of course very important that the fabric keep its calculated loop closeness and weight. The costs of the yarn alone is about 75 of the total manufacturing costs for average thick underwear of relatively simple yarns. For heavier fabrics or fabrics containing high quality cotton, wool, or more expensive artificial fibers, the yarn costs will be overpoweringly great in relation to the total manufacturing costs.

Weight control is thus a most important factor in the manufacture of such fabrics and it is usually performed by control of the weight per square unit or by counting the number of loops per length unit. The present invention relates to an apparatus for automatically performing such control with an accurateness hitherto unknown by means of an automatic adjustment of the, stitch length on the different feeders connected with the machine in question.

On machines having several feeders, it has hitherto been attempted to adjust the different feeders in such a way that they will produce equally large loops. Such an arrangement requires that the feeders take up equal lengths of yarn during each turn of the machine. In order to make the loops as equal as possible, there has been used to a great extent a method based on this condition. Equal yarn quantities are marked off on the yarn being fed at all the feeders, whereupon the machine is manually rotated until the marks approach the yarn guides and then observations and adjustments are made. The process is repeated until an acceptable evenness is obtained. The method has great drawbacks and on the market there are different instruments for facilitating an accurate adjustment during the operation of the knitting machine. Most of said instruments are ordinary yarn speed counters and are thus not ideal, since the knitting machines usually vary somewhat in speed during the adjustment thereof.

By using a known precision measuring instrument to measure the speed of the yarn and then comparing it with the rotation speed of the knitting machines, it is possible to determine that the variations between the yarn used by the different feeders is as high as 4% even with an accurate adjustment. On most modern circular knitting machines the adjustment is performed step by step at %2g" of length at a time. Each step will constitute a decrease or increase of 1% of the yarn consumption. Even with the best auxiliary means, the adjustment will often differ by several steps from the right one, inter alia depending on varying resistance occurring when the yarn is pulled from the spools, fluctuating temperature and speed of the machine, the feed of lubricating oil etc.

The primary object of the invention is to provide an apparatus which will overcome these drawbacks, said apparatus comprising a wheel adapted to be rotated by the yarn taken in by each feeder, means for transmitting said motion through suitable gearing to a first gear wheel having a threaded shaft threadedly engaged with another Patented Apr. 10, 1962 shaft having corresponding threads and which is driven at predetermined speed in relation to the machine speed, the first mentioned shaft being connected by means of a motion transmitting element with the guide for the cylinder cams of the knitting machine. Each difference in the speeds of the two shafts results in an axial change in position of said shafts in relation to each other, said change in position influencing the stitch length for adjusting the loop size which is predetermined by the rotation speed of the wheel relative to the speed of the machine.

Carefully made experiments have shown that the apparatus according to the invention equalizes the use of yarn fed by the different feeders of the machine. On a machine having two yarn feeders there were placed, after the automatic adjustment thereof, two spools having each 330 yards of yarn. When one of the feeders had taken in all the yarn, the other had 10" of length left. This involves an adjustment error of only about 0.1%.

The apparatus according to the invention can be used in connection with most types of circular knitting machines, but it is believed that it will also have great importance in connection with flat knitting machines. In accordance with the same principl s but with certain changes and further devices it could be used for stitch, length control on cotton machines in spite of the fact that the yarn for these machines is used up not only in a jerky motion but also with different length for each jerk because of a decrease in the number of loops of the stocking. No doubt, the invention increases the possibility of manufacturing ladies stockings having precisely equal length. By means of hitherto known methods such stockings are sorted and put together in pairs according to the length they are given during their manufacture. Such sorting and matching is greatly facilitated or even eliminated when the stockings are made on machines according to the invention.

In the following the invention will be illustrated with reference had to the accompanying drawings. In the drawings:

FIG. 1 shows diagrammatically a horizontal projection of a circular knitting machine provided with a stitch length control apparatus according to the invention and FIG. 2 shows on an enlarged scale a vertical section along the liners aa in FIG. 1 through the control ap paratus and discloses some parts of the circular knitting machine diagrammatically.

FIG. 1 will immediately be understood by anybody skilled in the art. Numeral 1 designates a heavy stationary ring in which is carried a ring 2 (FIG. 2) driving the cylindrical needle bed and onto which ring 1 the cylinder cam boxes 3 are screwed. Numeral 4 designates the cam boxes of the dial having yarn guides 5. The slidable guide members 6 of the cylinder cam boxes are shown without the usual device for their adjustment since this adjustment has to be carried out automatically by means of the control device 7 according to the invention. The control device '7 is fastened to the cylinder cam boxes 3. The yarn S is shown running a turn around the yarn wheel 9 which is partly surrounded by a conically shaped cap it which facilitates the insertion of the yarn into the notch of the yarn wheel. Each control apparatus also comprises a lever 11 bearing on guide members 6, each of which have upper and lower cam portions 12 and 13 (FIG. 2). The upper portion 12 bears on the feet 14 of the cylinder needles to move them down. A gear ring 15 runs in a notch formed in the ring 1. The gear ring 15 is driven by means of a special device having a worm and changeable gear wheels (not shown) with an approximate speed of .25 r./min. The speed of the ring could thus be varied but after each adjustment it is in a fixed relation to the rotation of the needle cylinder.

Each control device is provided with a gear wheel 16 the teeth of which engage the teeth of the gear ring 15 as shown in FIGS. 1 and 2.

The device itself comprises a two-part cover 17 (FIG. 2) enclosing a gear transmission for stepping down the speed of a wheel driven by the yarn. The transmission rotates an adjusting means which is coupled with the guide members 6 with their upper and lower cam portions 12 and 13.

The yarn wheel 9 and the gear wheel 18 are mounted on a thin shaft 24 carried in the cap It The lower end of the shaft 24 tapers and rests against the fiat upper end of a shaft 25 situated below said shaft 24 in the cover 17. Two pairs of gear wheels 20 and 22 are freely rotatably mounted on said shaft 25.

A shaft 26 parallel to the shaft 25, is at its lower end provided with left handed threads and on said shaft 26 there is attached a gear wheel 23. Two pairs of gear wheels 19 and 21 are freely rotatably mounted on the smaller (upper) part of the shaft 26. The threaded part 26a of the shaft 26 is threaded part way into a thicker shaft 27 journalled in the cover 17, and the gear wheel 16 is attached to the lower part of said shaft 27 by means of a bolt 28. The gear wheel 16 is driven by means of the gear ring 15' at the desired speed in relation to the speed of rotation of the needle cylinder as stated in the aforesaid.

The gearing down may of course be altered in accordance to different requirements. In the case here described the gear wheels 1322 have 12 teeth each. The gear wheels 1922 each have a larger gear wheel 19a--22a fixed thereto for rotation therewith, thus forming gear sets 15!, 19a-22, 22a. Larger gear wheels 19a22a each have 42 teeth. The small gear wheels 18-21 mesh with the larger gear wheels 19a-22a respectively. The gear sets 19, 19a-22, 22a are freely rotatably mounted on the shafts 25 and 26 as shown in FIG. 2. From the wheel 18 to the wheel 23, which also has 42 teeth and is attached to the shaft 26 and its threaded part 26a, the gears mesh five times. The relation between the speed of the yarn wheel and the wheel or the equal to 525 to 1.

The apparatus is filled up to the cover with a special oil low in viscosity. The cover 10 is provided with a disk 32 of unbreakable glass for preventing the oil from flowing away if the device is moderately inclined after the removal of the cylinder 5, said disk also protecting the oil against dust. The apparatus will have an easy and equal run and be very durable. In order to prevent leaks there is a packing ring 29 around the shaft 27 held in place by a bushing 30. Where the shaft 26 penetrates the cover 17, there is positioned a similar packing 31. These packings will probably have an unlimited durability as the shafts 26 and 27 rotate with an average speed of only about 4 r./min.

It is evident that if the gear wheel 23, FIG. 2, is blocked and the gear wheel 16 is rotated in a counterclockwise direction according to FIG. 1, the shaft 26 with its left hand threaded part 26a will be backed out of the shaft 27. The lever 11 is then moved upwards where it is in contact with the shaft 26. Because of the fact that the lever 11 is shaped as a balance arm resting on an edge 34, said lever will be tilted in a clockwise direction according to FIG. 2, the guide member 6 thereby being moved downwards into the cam boxes 3 which results in a lengthening of the loop and an increase in the consumption of yarn per each revolution of the needle cylinder.

On the other hand, if the gear wheel 16 is blocked and the gear wheel 9 is turned in a clockwise direction, the shaft 26 will by means of the gear train slowly be 4 threaded into the left hand threaded shaft 27. The spring 33 thereby expands and moves the guide member 6 to a higher position in the cam box, a shorter loop is thereby obtained and the consumption of yarn per revolution is decreased.

These two extreme examples illustrate the action of the device. It is evident that as soon as the speed of rotation of the shaft 26 does not correspond to the speed of rotation of the shaft 27, the stitch length will be increased or decreased until such a correspondence is reached.

The yarn wheel 9 in the embodiment described above is thought to rotate with a speed of 2200 r.p.m., said speed being geared down by means of the gear wheels 18-23 in such a way that the speed of rotation of the gear wheel 23 on the shaft 26 will be about 4 r.p.m. With such a gearing down of the speed of movement, the strength of thin, loosely twisted tricot yarns is sufficient for performing the small work required for threading the shaft 26 into the shaft 27 and it thus decreases the use of yarn in the feeder in question. The somewhat greater work necessary for threading said two shafts apart in such a way that the guide member 6 is lowered and the spring 33 is compressed to cause an increased use of yarn as a result is not accomplished by the yarn but by the primary movement of the apparatus, represented by the gear wheel 16 driven by the gear ring 15. The movement of the shaft 26 which occurs during a counter-clockwise rotation of the shaft 27 at a higher speed than the speed of the shaft 26 depending on the friction of the left hand threaded screw connection between the shafts will never force the wheel 9 to rotate with such a speed that the shaft 26 will be backed out of the shaft 27. The device must, however, be constructed so that the minor work performed by the yarn, when the primary movement of the wheel 16 exactly corresponds with the secondary movement of the wheel 23, is somewhat decreased if the feeder in question has a tendency to take up too little yarn while the work of the yarn increases somewhat if the feed has a tendency to take too much yarn in relation to the primary motion which is defined by the changeable gear wheel which drives the gear ring 15. The ring 15 and the changeable gear wheel may be called quality wheels as they, together with the thickness of the yarn, define the stiffness and weight of the fabrics.

There is thus obtained an equalizing effect which will enter into action before there is any real change in the length of the stitch. When working with very weak yarns it is advisable to give the threads of the shafts 26 and 27 a large pitch. Said threads could for instance have a double or multiple thread so that the primary wheel 16 not only drives the secondary wheel 23 and overcomes the friction of the shaft 26 at the journals and at the packing 31 and at its contact point with the lever 11, but will also give to the shaft 24 a slight driving effect. The work which has to be performed by the yarn, may thereby be decreased to any desired extent.

All of the rapidly rotating parts, e.g. 9, 24, 18, and 19 are small and light in order to diminish their intertial force in such a way that they will not continue to rotate when the machine is stopped. A suitable oil in the cover 17 is of great value in this connection. The members in question have, however, sufficient energy due to their motion that very quick pulls and jerks which often occur at least in usual tricot yarns will not reach the knitting point and breaks in the yarns are thereby eliminated.

As has earlier been pointed out the apparatus described works with great accurateness. It will always control sufiiciently well so that each one of the feeds takes up exactly the quantity of yarn per machine cycle, i.e. each revolution of the cylinder, which is defined by the quality wheel which drives ring gear 15. During very careful experiments on a circular knitting machine, a detector or an indicator in contact with the guide member 6 will show how the latter regains its position defined by the quality wheel with smaller variations in the length than 242043"- will give a compensating adjustment movement.

It is obvious from the foregoing and from the drawing that the adjusting movement takes place with a decreasing speed. Great errors will decrease rather quickly, whereas the final adjustment will require some time. If one of the yarn feeders of the machine is adjusted so that it takes up 20% more yarn than the other feeds on a 16" interlock machine having 16 feeders, the error will occur as streaks and shadow lines on the knitted fabric. When 8" of the fabric has been knitted, the error can hardly be seen by a human eye but an indicator on the guide member 6 indicates that the correct adjustment has been reached only after 20" of the fabric have been knitted. According to the described embodiment thus, about 330 yards must pass the yarn wheel 9 of the apparatus for equalizing an error of about 20%.

What I claim is:

1. An apparatus for automatically and continuously controlling the stitch length during operation of tricot or stocking knitting machines having yarn feeds and guide member controlled cams controlling the positions of the needles to control the stitch length, said apparatus comprising a wheel rotated by the yarn taken in by each of the yarn feeds of the machine, means driven by said Wheel for transmitting and gearing down said rotation, a first gear wheel driven by said transmitting and gearing down means and having a threaded shaft, a second gear wheel having an axially threaded shaft with which said shaft on said first gear wheel is engaged, said second gear wheel being driven at a predetermined speed in relation to the speed of the knitting machine, and a motion transmitting element between the shaft of said first gear wheel and the guide member, whereby each difference in the speeds of the first and second gear wheels results in an axial change in position of said shafts in relation to each other, said change of position influencing the guide member and the cams controlled thereby.

2. An apparatus as claimed in claim 1 in which said wheel rotated by the yarn and said means driven by said wheel have a small moment of inertia, whereby jerks from Also an only slightly higher friction on yard the yarn spools are taken up and smoothed out and the yarn wheel stops almost as soon as the feed of yarn is stopped, when the machine is stopped or the yarn breaks.

3. An apparatus for automatically and continuously controlling the stitch length during operation of tricot or stocking knitting machines having yarn feeds and cams controlling the positions of the needles to control the stitch length, said apparatus comprising a Wheel rotated by the yarn taken in by each of the yarn feeds of the machine, means driven by said Wheel for transmitting and gearing down said rotation, a first gear wheel driven by said transmitting and gearing down means and having a threaded shaft, a second gear Wheel having an axially threaded shaft with which said shaft on said first gear wheel is engaged, the pitch of said threaded shafts being high so that the force required on the said wheel for rotating the threaded shaft on said first gear Wheel will be small and the force for rotating the shaft on the second gear Wheel is great, said second gear wheel being driven at a predetermined speed in relation to the speed of the knitting machine, a motion transmitting element, one end of which is acted on by the said shaft on the first gear wheel, a movable guide member engaged by the other end of said motion transmitting element and acting on the needle cams for adjusting the position thereof, and spring means acting on said movable guide member opposing the action of said motion transmitting elements, whereby each difference in the speeds of the first and second gear wheels results in an axial change in position of said shafts in relation to each other, said change of position causing a change in position of said movable guide member and the cams moved therbey.

References Cited in the file of this patent UNITED STATES PATENTS 2,207,464 Lawson July 9, 1940 2,674,109 Bassist Apr. 6, 1954 FOREIGN PATENTS 756,028 Great Britain Aug. 29, 1956 757,483 Great Britain Sept. 19, 1956

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