US3174306A

US3174306A - Knitting machine

Info

Publication number: US3174306A
Application number: US73393A
Authority: US
Inventors: Robert H Lawson
Original assignee: Scott and Williams Inc
Current assignee: Scott and Williams Inc
Priority date: 1956-07-19
Filing date: 1960-12-02
Publication date: 1965-03-23
Anticipated expiration: 1982-03-23

Description

March 23, 1965 R. H. LAWSON 3,174,306

KNITTING MACHINE Original Filed July 19, 1956 11 Sheets-Sheet 1 INVENTOR. ROBERT H. LAWSON FIG. I.

ATTORNEYS R. H. LAWSON KNITTING MACHINE 7 March 23, 1965 11 Sheets-Sheet 2 Original Filed July 19, 1956 8 6 8 8 4 2 v v e 9 A 4 w I1... 6 "r2... B F m 9 o V m 0 8 :H. i I V. Y LHul M M L 4 E I8 6 R 3 6 2 6 O 6 2 6 W 0 l A R m 2 O u G F F 8 5 INVENTOR.

ROBERT H. LAWSON ATTORNEYS March 23, 1965 R. H. LAWSON 3,174,306

KNITTING MACHINE Original Filed July 19. 1956 11 Sheets-Sheet 3 VIII 1 INVENTOR.

ROBERT H. LAWSON BY ATTORNEYS March 23, 1965 R. H. LAWSON KNITTING MACHINE 11 Sheets-Sheet 4 Original Filed July 19. 1956 INVENTQR. ROBERT H. LAWSON ATTORNEYS March 23, 1965 R. H. LAWSON 3,174,306

KNITTING MACHINE Original Filed July 19. 1956 ll Sheets-Sheet 5 INVENTOR.

ROBERT H. LAWSON ATTOR N EYS FIG. I2.

ll Sheets-Sheet 6 Original Filed July 19. 1956 INVENTOR. ROBERT H. LAWSON BY Ki FIG. ls."

ATTORNEYS March 23, 1965 R. H. LAWSON 3,174,306

KNITTING MACHINE Original Filed July 19, 1956 ll Sheets-Sheet '7 F l G. l4.

FIG. l5.

INVENTOR.

ROBERT H. LAWSON ATTORNEYS March 23,- 1965 Original Filed July 19, 1956 R. H. LAWSON KNITTING MACHINE I 11 Sheets-Sheet a- FIG.

INVENTOR. ROBERT H. LAWSON ATTOR N EYS March 23, 1965 R. H. LAWSON 5 KNITTING MACHINE Original Filed July 19, 1956 11 Sheets-Sheet 9 FIG. I7.

FIG. l9.

IN VEN TOR.

FIG '& g OBERT H. LAWSON m My ATTOR NEYS March 23, 1965 R. H. LAWSON 3,174,306

KNITTING MACHINE Original Filed July 19. 1956 w 11 Sheets-Sheet l0 l (l. 5% qz y Y I INVENTOR. F G. 20. BY

March 23, 1965 R. H. LAWSON 3,174,305

KNITTING MACHINE Original Filed July 19. 1956 11 Sheets-Sheet 11 INVENTOR.

United States Patent 3,174,365 KNITTENG MAKE Robert H. Lawson, Pawtucket, Rh, assignor to Scott 8: Williams, Incorporated, Laconia, N.H., a corporation of Massachusetts Uriginal application .luly 19, 1956, Ser. No. 598,829, now Patent No. 3,629,619, dated Apr. 17, 1962. Divided and this application Dec. 2, 1960, Ser. No. 73,393

Claims. ((l'l. 66-54) This invention relates to knitting machines and has particular reference to the automatic control of stitch size and is particularly directed to machines for the knitting of sheer ladies hosiery.

This application is a division of my copending application Serial No. 598,829, filed July 19, 1956, and issued April 17, 1962, as Patent No. 3,029,619.

Difliculties are experienced in the knitting of sheer ladies hosiely, in particular, in that, due to variations in yarn and in the tension of yarn fed to the needles, stitches of varying length or size are produced. The variations in size of individual loops are minute, but due to the fact that a ladys stocking contains a very large number of courses, the minute variations of individual stitch lengths are cumulative to the end that successive stockings produced on the same machine and seemingly under identical conditions will vary greatly with the result that, after finishing, the stockings must be carefully sorted into pairs of approximately equal lengths. Furthermore, while the intention may be to produce stockings of particular lengths, there may be produced undesired numbers of stockings varying so far from the desired lengths that for a mill to fill an order an excessive number of stockings may have to be produced, the stockings of undesired lengths being then retained in hopes of filling an order requiringtheir lengths.

Furthermore, the variations in stitch lengths may occur in such fashion that groups of courses having stitches of abnormal lengths may be interposed between groups of courses having stitches of normal lengths, and the result in such cases will be the appearance of horizontal shadowy streaks which may make the stockings unacceptable.

Further, stitches may vary in size sufiiciently to produce abnormal reductions or increases in stocking circumference causing the stocking to be locally too tight or too loose when worn.

The variations indicated above as of objectionable type are not to be understood as those which are intentionaliy provided for the shaping of stockings. it is common practice to change stitch size in a smoothly continuous fashion in shaping ladies hosiery from the calf portions into the ankle portions. Such variations are definitely programmed by the controlling mechanism of the knitting machine. The objectionable variations here under discussion are those which normally occur beyond intentional control.

In the US. patent to Vernon Thomas Stack, No. 2,685,786, dated August 10, 1954, there is disclosed mechanism in a knitting machine for the automatic control of stitch lengths having as its object the prevention of shadow streaks or rings, the production of proper stocking diameters, and the attainment of stocking of desired overall lengths. In accordance with the mechanism of said Stack patent, there is provided detection of variations of lengths of stitches as the stitches are being formed, with provision for correction of stitch lengths so as to avoid the cumulative occurrence of stitches in large groups of successive courses which would lead to the objectionable results above discussed. In brief, in accordance with the said patent, the positions of sinkers are detected to give rise to signals indicative of variations of stitch lengths from normal, and the signals thus produced control through reversible electric motor means devices which change the relative positions of the stitch drawing needle cams and the ledges of sinkers over which the stitches are drawn. The mechanism so shown allows for the intentional variations of stitch length incidental to the usual fashioning or shaping procedure, but prevents deviations from the locally normal stitch lengths in such fashion that cumulative errors do not occur.

It is the general object of the present invention to improve the mechanism of the general type disclosed in said Stack patent for the purpose of control of the stitch lengths.

In accordance with the present invention, the control is pneumatic rather than electrical. The pneumatic control 1 have provided produces smooth and reliable operations, avoiding the possibilities of failure of electrical elements and the complexities involved in electrical control. Furthermore, from a practical standpoint, a single type of pneumatic mechanism may be provided for all localities, domestic and foreign since, except for a driving motor for the air supply, it is independent of the local power supply which may vary from place to place in voltage and frequency and would necessitate the provision of wholly different electrical systems for various places. Due to the relatively slow and smooth action of the pneumatic control provided, sudden variations in stitch lengths or sizes are prevented, and this is highly desirable since any sudden change in stitch length will be noticeable as a streak or mark in the fabric. Desirably the corrective actions should be slow so that in successive courses, even though a corrective action is taking place, there will be no change in stitch length which will be apparent to the eye.

The foregoing and other objects particularly relating to details will become apparent from the following decription read in conjunction with the accompanying drawings in which:

FIGURE 1 is an elevation, partly in section, showing in particular certain conventional elements of the type of knitting machine to which the invention may be applied;

FIGURE 2 is a diagram illustrating the connections of a preferred type of pneumatic system;

FIGURE 3 is a plan view of a suitable type of pneumatic relay utilized in carrying out the invention;

FIGURE 4 is a vertical section taken on the plane indicated at 4-4 in FIGURE 3;

FZGURE 5 is an enlarged vertical section taken on the broken surface indicated at 55 in FIGURE 3;

FlGURE 6 is a vertical section taken on the plane indicated at 6-6 in FIGURE 3;

FIGURE 7 is a fragmentary plan view showing in particular the detecting means for abnormal stitch length;

FIGURE 8 is a perspective view showing the details of the detector;

FIGURE 9 is a further perspective view showing details of the detector;

FIGURE 10 is a fragmentary elevation showing certain elements particularly involved in the fashioning control of the stocking formation;

FIGURES 11 and 12 are fragmentary elevations, partly in section, showing certain details of the controlling mechanism;

FIGURE 13 is a fragmentary plan view of the stitch control arrangement involving control of the penetration of the sinkers between the needles;

FIGURE 14 is a fragmentary elevation, partly in section, of a portion of the mechanism shown in FIGURE 13;

FIGURE is a fragmentary elevation of a portion of the mechanism shown in FIGURE 13;

FIGURE 16 is a fragmentary elevation illustrating a valve control provided in the machine;

FIGURE 17 is a diagrammatic elevation showing certain air controls involved in the machine;

FIGURE 18 is a fragmentary elevation showing valve operating means controlled in accordance with operation of the machine;

FIGURE 19 is a sectional view of the same;

FIGURE 20 is a sectional view showing, in particular, a type of sinker which may be used for stitch control;

FIGURE 21 is a fragmentary plan view showing the stitch control arrangement involving control of the positioning of sinkers of the type shown in FIGURE 20;

FIGURE 22 is an elevation, partly in section, of the mechanism shown in FIGURE 21;

FIGURE 23 is a fragmentary elevation showing mechanism for securing control of stitch length by shift of position of the sinker cap; and

FIGURE 24 is an elevation looking at the right of FIGURE 23.

As noted above, the invention is particularly applicable to knitting machines for the production of ladies sheer hosiery wherein the matter of stitch control is particularly important, though it will be evident that the invention is more broadly applicable to knitting machines generally.

For purposes of illustration, the invention will be described as applied to a machine of the type arranged to knit ladies sheer-hosiery, the machine which will specifically be referred to being of the type disclosed in our US. Patents No. 2,625,026, dated January 13, 1953, and No. 2,709,352, dated May 31, 1955. Such a machine, certain parts of which are indicated in FIGURE 1, comprises a slotted needle cylinder 2 associated with which is the non-rotating but axially movable cylinder raising tube 4 which is vertically moved for the purpose of control of stitch length. Heretofore such a tube has been raised intermittently to control changes in stitch length as between major parts of the complete stocking and in particular where yarn changes have been effected, and also for the gradual control of stitch length to produce proper fashioning of a stocking from the calf into the ankle. The adjustment of stitch length in this fashion is well known and is the result of changing the vertical height relationship between the ledges of the sinkers 8, over which the stitches are drawn by the needles 6, with respect to the level of the cams (not shown) which are at a generally fixed height and control the needle movements.

The machine is illustrated as comprising also the dial 10 which carries transfer elements 12 for the production of turned welts. Also indicated is a grab takeup 14 of the typedescribed in detail in my prior patent and application, which takeup makes possible the maintenance of proper tension during the knitting of stockings which are individually and separately knit, each being started on bare needles. In the remaining portion of the description herein there will be referred to only those elements which are intimately concerned with the invention herein involved, it being understood that the knitting machine is otherwise of conventional type arranged to knit complete stockings including heels and toes.

Reference may first be made to a pneumatic relay shown in FIGURES 3 to 6, inclusive, two of such relays being used in the various pneumatic control systems hereinafter referred to. The relay comprises a multipart housing 16 which provides various air connections and chambers and contains operating valve means. The housing provides an air supply passage 18 which communicates through a passage 20 with a chamber 22. The passage 18 also communicates through a restricted orifice 24 with a passage 26 which at one end 28 is arranged to be connected to a nozzle as will be hereafter described and at its other end through extension '38 to a chamber 32 a portion of the lower wall of which is provided by a flexible diaphragm 34. The diaphragm 34 carries a conical valve member 36 which cooperates with a conical seat portion 38 of a passage 39 which connects the space 40 beneath the diaphragm 34 with the chamber 22. The valve member 36 is provided with a stem 42 of smaller diameter than the passage 39 which is arranged to engage and press downwardly a ball 44 which acts as a valve member to seat in the lower end of the passage 39 to close the passage, the ball 44 being urged upwardly by a light leaf spring 46. Passages 48 and 5t furnish communication between the space 40 and the atmosphere. Communicating with, and extending laterally from the passage 39 is a passage 52 which, through its

extensions

54 and 56 provides a controlled air outlet.

As will hereafter appear, a nozzle connected to the end 28 of passage 26 is controlled by a movable baffle which, by impeding the escape of air to the atmosphere produces, in conjunction with the fixed orifice 24, a variable pressure condition in the connection 30 and the chamber 32. As the pressure in this chamber increases, the valve member 36 is moved by diaphragm 34 toward a position closing the upper end of passage 39 and unseating the ball 44 from the lower end of this passage so that communication is afiorded between the chamber 22, which received the supply air, and the air outlet at 56. On the other hand, if the flow of air from 28 is relatively unimpeded by movement of the baflie away from the corresponding nozzle, the pressure in chamber 32 is reduced due to the resistance to How imposed by the orifice at 24, and the diaphragm 34 is raised by the action of spring 46 which seats the ball 44 and raises the valve member 36 so that the passage 39 is put in communication with the atmosphere through the space 40 and the venting

passages

48 and 50. The result is that, when the valve member 36 is in fully opened position, .the outlet 56 is connected to the atmosphere. In this fashion a relay action is secured providing either the supply pressure or atmospheric pressure at the outlet 56 in dependence upon-the position of a bafiie associated with a nozzle connected to the end 28 of passage 26. Relays of this type are well known in indutstrial uses, and details of its operation need not be described. It will sufiice for the present instance to state that the relay is capable of providing a very large pressure difference under control of minute movements of the baflie referred to.

FIGURE 2 shows a typical diagram of a pneumatic system incorporating relays of the type just described which may be used forstitch control purposes in the various arrangements hereafter discussed. Air is supplied at suitable high pressure at 58 through a filter 60 to a reducing valve 62 adjustable by means of a knob 61 so as to provide the desired input pressure to the

relays

64 and 66, through a valve 63 which, as shown in FIGURE 16 is controlled through an arm 65 which is connected by link 67 to an extension of the conventional lever 69 activated by the pattern chain 71 to enable the usual pawl 73 to engage the drum ratchet Wheel 75. Reducing valves are well known which will maintain substantially constant output pressure for large fluctuations of input pressure and such valves are desirably used in a mill where the supply pressure may fluctuate considerably in view of intermittent uses of large amounts of air for other purposes associated with a number of knitting machines. The control connections 68 and for the relays, corresponding to connections to the passage 26 at 28 of the relay already described, terminate in

nozzles

184 and 186 with which cooperate baffles 168 and 170 arranged to control the outflow of air from the nozzles. While a pair of baffles are shown herein it has been found that equally satisfactory results may be obtained by one baflle operating between directly opposed nozzles. However, the principle of control of the double baffles shown herein applies to control of the single .bafiie. The relay 64 is shown as awasos having its output connected at 89 to an accumulator 32 in the form of a tank containing oil. The oil-containing space of this accumulator 82 is connected to one end of a cylinder 84 through a connection 36 controlled by an adjustable valve 88. The cylinder 84 contains a piston 92 to which is secured a piston rod 94 from which mechanical power is derived. The output of the relay 66 is connected at 5 through a filter 91 to the side of the piston opposite that supplied through connection 85. Filter 91 is so arranged that any liquid leaking past piston 92 will be prevented from entering relay 66. Considering specifically the arrangement shown in FIGURE 2 (which may be replaced by numerous pneumatic arrangements known to the ant), if the bathe 168 approaches more closely to the nozzle 134, pressure in the relay 64 will be built up above the diaphragm 34 thereof providing pressure air from the supply through the connection 80 to displace oil from the accumulator 82 to drive the piston 92 downwardly. The valve 83 is desirable since, by partial closure of this valve, the oil flow, due to its viscosity, may be slowed down to provide a smooth slow movement of the piston 92 rather than a rapid movement. Slow movement is desirable not only to prevent hunting but further in the case of stitch length adjustment since a rapid adjustment of stitch length might result in such a sharp change in the stitches that a visible shadow ring or other marking might result. Desirably the change is a gradual one so that substantial change will not occur except over a knitting period of several courses. As will be evident, if the baffle 17% is moved toward its nozzle and the baflie 16S simultaneously moved away from its nozzle a reverse action will occur involving upward movement of the piston 92 and reverse flow of oil through connection 86 and valve 88 from the cylinder to the accumulator. As will appear hereafter the baffles 165 and 170 are moved oppositely with respect to their nozzles so that reverse movements of the piston 92 correspondingly occur to effect corrective actions in one of the fashions which will be described. It may be noted that the pneumatic control may be of one of the more elaborate types well known in the process control art to achieve fine control with avoidance of hunting, though the simple control described has been found highly satisfactory for stitch control purposes.

It is desirable in machines of the type herein disclosed to shut or? the main air supply when the machine stops due to the operation of the stop motion or for other cause such as failure of the main power supply or manual stopping of said machine. Heretofore, air used in conjunction with a grab take-up has been shut oti, when the machine was manually stopped, to prevent waste of air.

In the present instance, where the stitch size is servo controlled through a detector cam 150, the control action or which is hereafter described, stopping of the machine with the air on may cause the piston 92 to travel to its extreme in one direction or the other depending upon which of the

relays

64 and 66 happens to be activated when the machine stops, if the comparatively simple system herein described is used. An extreme stitch such as would be obtained when the piston 92 goes to one extreme or the other in its cylinder 84 would cause ditficulty in restarting the machine due to the stitch being too tight or loose and of course would in any case result in loss of the stocking.

One example of a control for shutting oif the air when the machine stops for any reason is shown in FIGURES 17, 13 and 19. This control consists of housings 590 and 592 held together by screws 504. A shaft 566 carrying a bladed rotor 598 passes thru bearings 510 and 512 respectively in housings 500 and 5192. These bearings carry seals such as may be provided by 0 rings to prevent lubricant inside housings S00 and 562 from passing out between rotating shaft and bearings 519 and 512. Shaft 506 also carries fastened thereto a gear 514 which meshes with the bull gear 51s with which ma chines of the type here disclosed are equipped, being used to drive a quadrant gear (not shown) through a connecting rod (not shown) to oscillate the cylinder during the making of heels and toes. Gear 516 always travels in one direction regardless of whether the needles are revolving or reciprocating.

Bladed rotor 55% is made integral with shaft 506 as by brazing and as said shaft 556 is caused to rotate the rotor 508 revolves inside

housings

500 and 502. Housings 5% and 592 are provided with cavities separated by walls and the latter approach the blades of rotor 508, being separated therefrom by a very small clearance being measured in one or two thousandths of an inch. Housings 5% and 502 with the rotor 508 therein are completely tilled with a grease that will substantially maintain its density over a wide heat range, for example, a silicone grease. The movement of the grease caused by the angular blades on rotor 508 from cavities in one of the

housings

500 and 502 to the cavities in the other housing causes a torque to be applied to said housings which varies as the speed with which rotor 5% is turned.

This device has been so designed and the gear ratio between 516 and 514- is such that when the machine is run at its slowest normal speed sufficient torque is built up in housings 5th) and 5:32 to cause them to revolve clockwise as seen in FIGURE 18 against the tension applied by a spring 513 thus opening a valve 52%) through a link 522. Spring 518 acts normally to close valve 520 immediately upon stopping of the machine with consequent loss of torque to housings Silt) and 502. Spring 518 through link 522 revolves said housings 50% and 5432 anti-clockwise (FIGURE 18) lifting the lever of valve 524 and closing the valve.

Air is suppled to valve 52% immediately following its passage through filter and before entering an air controlled pilot operated valve 524 located between filter 60 and reducing valve 62. Thus air is available to valve 529 regardless of whether valve 524 is open or closed but air is available to the grab take-up and the pneumatic stitch control only when valve 524 is open. Running of the machine causes housings 5% and 592 to revolve clockwise as explained above overcoming the tension in spring 518 and opening valve 520 thus supplying air to the pilot side of valve 524 causing the opening of said valve 524 and the consequent supplying of air to various parts of the machine as required. Stopping'of the machine or even abnormal slowing down of the machine releases the torque built up in housings 569 and 502 allowing spring 518 to returnthem to a position where thru connection 522 they will cause valve 529 to close, which in turn shuts off main valve 524.

Changing the density of grease in housings 5% and 562, changing the relative diameters of these housings and rotor S98 and also changing the tenson in spring 518 will cause opening and closing of valve 520 to occur at different speeds of the knitting machine as may be desired.

The physical arrangement of the accumulator S2 and cylinder 84- and their associated parts, diagrammed in FIGURE 2, is shown in FIGURE 17, the accumulator and cylinder being secured to a leg of the knitting machine as illustrated therein. The piston rod 94 has connected to it a plate 96 which through a link 98 is connected to operate the devices changing stitch size by control of the sinker movements.

The shaft 142 of the main pattern drum of the machine, which is conventional and not shown, has secured to it, by location on its driving gear, a cam 144 which is arranged to operate on a plunger 146 which is connected to a link 148. This serves for activation or deactivation of the pneumatic controlling means as will appear hereafter.

Reference is now made to FIGURES 7, 8 and 9 which illustrate the stitch sensing mechanism, tlus mechanism also being illustrated in an exploded view comprising FIGURE 9A of Patent 3,029,619 previously referred to hereinabove.

A detector cam 150 which rides on the butts of sinkers 8 is pivoted at 152 in a slot in the sinker cap. Engageable with this detector cam is the depending finger 154 of a lever 156 which is pivoted on a pin 158 fixed in a slide 160 which is slidable toward and from the axis of the needle cylinder in a fixed bracket 162.. Two

other levers

164 and 166 are also mounted to pivot on the pin 158 and carry respectively the

battles

168 and 170. Lever 156 is provided with a lateral extension 172 in which is threaded an adjustable screw 174 the lower end of which is arranged to bear upon the bafiie 178. A spring 176 between the bafile and screw urge them into engagement. An extension 178 of lever 164 has threaded therein an adjustable screw 180 which bears upon the end of lever 156. A spring 182 reacting between the screw 188 and a fixed element serves normally to maintain the engagement between screw 180 and the lever 156. The

bafiles

168 and 170 cooperate, respectively, with the

nozzles

184 and 186 as illustrated in FIGURE 2, and opening, respectively upwardly and downwardly. As will be evident from the prior description of FIGURE 2, when the battle 176 closes off the flow of air from nozzle 186 there will be built up pressure beneath the piston 92 to effect rise of the piston. On the other hand, if bafile 168 closes nozzle 184 the piston will be moved downwardly.

' A wedge 188 is arranged for vertical movement in the bracket 162 and is moved by a heavy Bowden wire 1% which extends through a sheath 192 and is connected at its other end to a lever 194. The slide 169 is provided at its outer end with a plate 196 in which is threaded an adjustable screw 198 which rides on the wedge 188. A spring 200 urges the slide 160 toward the axis of the needle cylinder. A lever 202 which is pivoted to the frame at 204 is connected at 206 to an adjustable extension 208 of the link 148. The outer end of the lever 202 engages the plate 196 so that, as link 148 is raised through the action of cam 144 the slide 160 is moved outwardly from the needle cylinder. Secured to the upper end of link 148 is a block 210 which is provided with a wire arm 212 having a portion 214 underlying the baflle 168. The arrangement is such that as the link 148 is raised the baflle 168 is raised away from its nozzle 184.

- The lever 194 to which reference has alreday been made is pivoted at 216 to a bracket 218 and is provided with three aligned adjustable screws 220 only one or" which appears in FIGURE 10. These screws are respectively adapted to be engaged by

cams

222, 224 and 226 carried by the fashioning drum 138 which is journalled on the shaft 142 as shown in FIGURE 11. The fashioning drum is provided with ratchet teeth 228 extending approximately two-thirds of the way about its circumference and arranged to be acted upon in usual fashion by a pawl 229 which reciprocates during operation of the machine. An adjustable screw 230 is mounted in the lever 4 and is arranged to limit its counterclockwise movement under the action of spring 234 by abutment with lateral extension 232 of the bracket 218.- The cam 222 is contacted by lip 238 to advance drum 138 where teeth 228 are omitted. Said lip 238 is provided on a plate 239 secured to the shaft 142. A spring brake 240 holds the fashioning drum 138 in position against accidental displacement and also serves to restrain overrun of this drum.

FIGURES 13, 14 and 15 show the arrangement for changing stitch size by control of the sinker movements. The sinker cap 242 is provided with a sinker butt detector cam 150 pivoted at 152 and arranged to act upon the lever 248.

The center sinker cam 250 is of generally conventional shape but in this case is pivoted at 252. The rundown castofi' sinker cam 254 is pivoted at 256. This cam also 8 is substantially in its shape conventional, though the ad jacent portions of the

cams

250 and 254 are modified so that during simultaneous movements they will not pinch the sinker butts.

Pins

258 and 260, respectively carried by the

cams

250 and 254, extend upwardly through slots in the sinker cap and are pivoted in openings in a plate 262 which is also pivoted at 256, being provided with an extension 264 acted upon by a spring 266 serving to urge the plate 262 counterclockwise. A bracket 268 carried by the sinker cap is threaded to receive an adjustable stop screw 27% which bears against the outside of earn 254 to limit its outward movements. A bracket secured to the latch ring support post 272 is provided with guiide elements 274 for a slide 276 which is provided with an enlarged T-shaped head 278 limiting its inward movement. A spring 289 urges the slide 276 outwardly. A lever 282 pivoted at 284 and operable by a thrust rod 286 acted upon by cams on the main cam drum, is provided with a pad 288 urged outwardly of its upper end by a strong spring 290 capable of overcoming the tension of spring 280. Pivoted at 292 on slide 276 is a lever 294 provided with a horizontal arm engageable by the link 98, previously described. At its upper end the lever 294 is provided with an eccentric cam 298"engaging, when in operative position, the plate 262 and arranged to rock it about its pivot 256 against the action of spring 266.

Depending upon the connections of the elements just described operations may be effected in various diiferent Ways for control of stitches by producing greater or less inward movements of the sinkers under the action of cam 254. It may be noted that cam 250 is movable with cam 254 to provide control against overrun of the sinkers while still avoiding pinching of the sinker butts. The stitch controlling action, however, is dependent upon the position or" the rundown castolf sinker cam 254. That is, the castofi movements of the sinkers are controlled for correcting the size of the stitches.

During the knitting of portion of a stocking in which no control is effected, the thrust rod 286 is in lowered position so that the spring 280 is free to retract the slide 276 and with it the cam 298, freeing the plate 262. It.

may be noted that under these conditions there is no possible conflict with reciprocatory movements of the latch ring during the knitting of heels and toes. The detecting means and the pneumatic control means may be completely deactivated by the withdrawal of the slide carrying the lever 248 along with deactivation of the bafile corresponding to 168. When stitch control is desired, thrust rod 286 is moved upwardly to force the slide 276 to its extreme inner position, thereby locating the cam 298 in position for operation. Control of a wedge such as 188 under the action of pattern devices of the type already described then controls the size of stitches detected by the cam 158 following the sinkers 8 and eifecting movement through the piston of the lever 294 and cam 298. If longer stitches are called for, the action is to drop lever 294 so as to move inwardly cam 254 and thereby cause the sinkers to draw longer stitches as they are formed. It may be noted that the movements of the cam 254 by reason of its pivotal mounting are such as to move the sinkers inwardly slightly earlier than usual and also slightly further than usual when the cam 254 is moved inwardly. By difierent' mounting of the cam either of these actions alone may be used for the control of stitch size. If earlier inward movement of the sinkers is depended upon for control, the sinker cap may be moved by a mechanism of obvious type controlled through a thrust rod corresponding to 286. Conversely if stitches that are too large are being formed, the operation is such as to permit outward movement of cam 254 under the action of spring 266 thereby effecting the formation of smaller stitches.

' During the makeup. at the start of the stocking the height of the needle cylinder is controlled in the usual manner from the main cam drum of the machine. At this time the piston 92 will be in the position resulting from the formation of the ankle of a previous stocking, and will he, therefore, in a lowered position corresponding to automatic control of tight stitches. The follower 146 is at this time raised by earn 144 and, consequently, the slide 16% is in retracted position with the result that baffle 170 is clear of the nozzle 186. At the same time the end 214 of wire 212 holds the battle 168 raised from nozzle 184. The air system is accordingly deactivated, so that the piston remains as stated. If desired, the air system may also be deactivated by closure of an air valve from the main cam drum, though such deactivation would serve no purpose except to prevent waste of air through the nozzles.

During the fashioning of the ankle of the preceding stocking the pawl 229 will have advanced the ratchet 228 until, following the engagement of the trailing tooth, it will be riding idly upon the portion of the drum 138 which has no teeth. During the formation of the heel, foot, and toe of the preceding stocking and the initial part of the makeup of the new stocking the shaft 142 will have stepped about, but will not have caused lip 233 to engage the portion 236 of cam 222. During the last drum move involved in the makeup, the shaft 142 will have a step so that 238 will engage 236 to move the cam 222 beneath the corresponding screw 22% to position the lever 194 and the wedge 18% properly for the making of welt stitches.

esirably at this same time the usual cams are moved to effect movement of the needle cylinder to a height which would correspond to the production of welt stitches slightly tighter than desired, and also to raise thrust rod 286 so that the stitch size controlling means will be rendered operative.

Also at this time the rod 1.46 is released by the cam 144. The result is that bafiie 163 is released and and the slide 16% moves inwardly to engage follower screw 198 with the wedge 188 occupying now a position corresponding to the production of proper size welt stitches. The sinker detector cam will now in a position slightly outwardly of that desired in view of the formation of welt stitches tighter than desired, and consequently lever 156 will be rocked counterclockwise to engage baflle 1'79 with nozzle 186. The piston will accordingly be caused to rise as already described to move the link 93 in the direction to eilect a proper positioning of earns and 254-. As slackening of stitches results, the sinkers are moved inwardly under the action of detector cam 50 through the action of spring 182, effecting removal of bafiie 176 from nozzle 186, thereby arresting the piston movement. Control in this fashion is typically attained within one or two courses after the pneumatic stitch control device is activated, though the rapidity of action of this control is adjustable through control of valve 83.

During the knitting of the welt automatic stitch length control continues. If the stitches become too tight, the detector cam 15% is moved outwardly by the sinkers resulting in closure of nozzle 18% by baffle 17% and slight readjustment of the

cams

256 and 254 by the raising of lever 294. On the other hand, if the stitches become too loose, the follower cam 15% moves inwardly with the result that nozzle 184 is closed by baffle 168 resulting in slight downward adjustment of the lever 294. Desirably, the automatic adjustment is relatively slow, so that there is no radical change in size of the stitches such as would produce an appearance of rings in the fabric. It may be noted that the stitch adjustment is not an adjustment of abnormal stitches already drawn, but rather is in the nature of a compensating adjustment of subsequently formed stitches both to balance the abnormal stitches and secure stitches of more proper length. This action of compensating for stitches of abnormal size is important throughout the formation of the circular knit parts of a stocking, and particularly the leg, to be sure of proper overall size of the stockings produced.

Continuing the description of the operation, following the transfer of the welt the drum 138 is advanced by engagement of lip 233 with cam end 236 to release cam 2-22 from its follower screw and to bring earn 224 into engagement with a second one of the screws 22% to position the wedge 188 properly for the formation of shadow welt stitches. The action is, of course, to reposition the slide res so that the automatic control may be etfect'ed from a different predetermined value of stitch length. Automatic control would then take place as before, and the screw 22% which follows cam 224 may be adjusted to secure the desired stitch length. It may be here remarked that adjustment of screw 1% is primarily to effect a common adjustment of all stitches while the relative positions of the screws 22% effect relative adjustment to the stitches in the different areas of the stocking.

At the beginning of formation of the leg actions similar to those just described take place, the drum 138 being again advanced so that the third screw 226 engages the initial portion of cam 226 to set the wedge 188 to proper position for the additional leg stitches. Again the needle cylinder is lowered by means of the usual cam drum to etfect quick change of stitch size, which is followed by automatic readjustment of the piston 92 to accomplish, through link 98, automatic control of the stitches in accordance with the position of the wedge 188. As discussed in greater detail hereafter, the primary control over fashioning of the leg may be effected by the usual means acting to raise and lower the needle cylinder or such fashioning may be effected solely through adjustment of wedge 188. Thus the automatic control is called upon merely to effect such minor adjustments as are required in view of variations in yarn tensions, or other matters which may elfect stitch size.

Through the events already described the drum 138 has not been advanced sufliciently to permit engagement of pawl 229 with the leading tooth of the ratchet 228. At the time fashioning of the leg is to start, lip 238 will advance the end 236 of cam 222 to an extent bringing the leading ratchet tooth in position to be engaged by pawl 229. Thereafter, drum 138 is advanced through an arc corresponding to one tooth, desirably once for each four revolutions of the needle :cylinder. The follower screw of lever 194 which follows earn 226 then rides down this cam producing step by step small incremental upward movements of wedge 1S8 thereby causing slide 160 to be retracted from the axis of the needle cylinder. Thus there is produced progressive tightening of the stitches as determined by cam 226, the automatic control, of course, functioning mso to maintain the stitches of the desired size, on the average, despite other factors such as changes in yarn tensions, temperature changes, or the like. The automatic fashioning control action just described is terminated when the screw 230 engages the portion 232 of bracket 218. The adjustment of screw 230 accordingly controls the minimum stitch size involved in the production of the ankle and also the foot.

At the start of the heel the automatic control is rendered inopenative by the action of cam 144 which raises rod 146 and link 148 to deactivate the control by locating its parts in the positions first described in this discussion of operation. Also, thrust rod 286 is lowered to render the automatic stitch size controlling means inoperative as heretofore described. As the result of knitting tight stitches in the ankle, the lever 122 will occupy a low position and will remain in this position due to the deactivation of the control. Accordingly the needle cylinder may be naised by the usual cams on the main cam drum to the proper position for the formation of desired heel stitches.

At the completion of the heel the automatic control may be resumed or not as desired. The arrangement specifically shown for the cam 144 in FIGURE 12 assurnes that control is to be renewed during the formation of the foot of the stocking. The depression in the cam 144 permits the control to be reactivated in passing from the heel to the foot. Generally, to provide avoid- 1 l ance of a sharp line of demarkation of stitches across the instep the wedge 188 will desirably continue in the position last occupied prior to the formation of the heel, i.e., the position in which screw 230 engages step 232. However, while this may be the initial position it will be obvious that fashioning may occur through the foot, involving widening thereof, by continuation of control under the action of cam 226 serving to rock the lever 194 so as to exert downward movement on the wire 190. Then when the knitting of the tee is started another high section of the cam 144 operates to deactivate the automatic control.

For automatic control of the foot stitches it is desirable to control the valve 63 from the pawl holder 69 as shown in FIGURE 16, the valve shutting ofi the air to the system from a time prior to completion of the heel until the pawl holder rides ofi the link of the chain 71 two courses after going out of the heel. Otherwise, the tight heel stitches would operate cam 150 so as to call for a looser stitch and the piston 92 would move far enough to make a loose course at the start of the foot. Accord ingly, the control is held inoperative after plunger 146 drops into depression 145 until foot stitches are detected, whereupon the automatic control continues, being initiated by reopening of valve 63. The drum 138 continues to step around untilthe last tooth of the ratchet 228 has been advanced. Thereupon the drum comes to rest, to be next moved by lip 233 as previously described.

Although the automatic control may be used for fashioning, preferably its action is confined essentially to control of the stitch size against a normal magnitude by having the vertical relation between the needle and sinker controlled in theusual Way from the main cam drum both for stitch changes in different parts of the stocking and also for fashioning, the automatic control only taking care of variations caused by the yarn, temperature change, etc. In transitions from the welt to the shadow welt or from the shadow welt to the leg the needle cylinder may be rapidly moved to change the stitch size and at the same [time the Wedge 188 may also be rapidly moved. However, the control will then ordinarily be temporarily rendered ineffective since, as previously discussed, it is desirable that the automatic control should take place slowly. Nevertheless, quick transitions in stitch size will occur and after one or more revolutions of the needle cylinder the automatic control will become operative to take care of corrections of minor variations due to changes in yarn tension and other causes, the control being, however, about the desired stitch length determined primarily by the cylinder position.

In similar fashion, the fashioning in the leg of the stocking is preferably primarily eifected by reason of the adjustment of needle cylinder position. While the wedge 188 must be moved to correspond to thefashioning desired, what has just been stated means that the sinkers need have very little variations in their position, only suflicient to etfect minor corrections. On the other hand, if there is dependence upon them for complete fashioning, then they will have correspondingly large variations in their paths with necessity for substantial movements of cam 254 throughout the full range of operation.

A device for resetting the piston 92 will be described with reference to FIGURE 17. At the completion of the stocking piston 92 will be in its lowest position, where it was placed to make the tight stitch required in the ankle and foot. preferably during the making of the loopers waste courses, master switch 526 (a normally open switch) is closed by a cam 528 located on the main drum. This will cause current to flow through a normally closed switch 492' causing solenoid operated valve 530 to open supplying air to the bottom of cylinder 84. Air thus supplied will cause piston 92 to rise. A cam 476' fastened to slide 96 will cause switch 492 to .open when piston 92 has reached the desired height, deenergizing solenoid During the completion of the toe, or

12 valve 530 and shutting off the air to the base of cylinder 84 and leaving piston 92 at the height desired for starting the welt. The next drum move will open switch 526 so solenoid valve 530 will not operate until the end of the next stocking is reached.

The stitch control may involve the use of sinkers having sloping ledges over which the stitches are drawn by the needles, with variations of sinker positions at the time the stitches are drawn. Such an arrangement is illustrated in FIGURES 20, 21 and 22. The type of sinker which may be used is illustrated at 8' in FIGURE 20 and is shown as comprising a sloping ledge portion 300 associated with the horizontal ledge portion 301 adjacent to the sinker throat. Various sinker constructions may be used with the sloping ledge. 300 at greater or less angle and either associated with a horizontal ledge 301 or extending in sloping fashion to the sinker throat. If the automatic adjustments effected by radial sinker position are to be for minor corrections of stitch length a slight slope only is required. However, if the sinker positions are depended upon for major changes in stitch lengths then the slope may be quite steep.

FIGURES 21 and 22 illustrate a desirable .type of mechanism for controlling the sinker positions. The sinker cap is indicated at 302 and supports the castofii cam 304 which, in this case may be fixed in position. The center cam desirably has two parts, the first, indi' cated at 306, being pivoted at 308 and the second indicated at 310 being fixed and secured at the

points

312 and 314. These two cams overlap in the region 316 to present, for all positions of adjustment of cam 306 a smooth cam arrangement for operating on the sinker butts during either direction of movement. The spring band 317 urges the sinkers inwardly to cause them to follow the cam 306. The cam 306 at its free end is connected through a pin 31% to a plate 320 which is pivoted at 321 and is limited in its clockwise movement as viewed in FIGURE 21 by an adjustable eccentric stop 322. The plate 320 is provided with a hook portion 324 which is substantially concentric with the needle cylinder axis. This permits reciprocations of the sinker cap during reciprocatory knitting. The hook portion 324 is arranged to be engaged by the upstanding portion 326 of a bell crank 328 pivoted at 330 to a slide 332 which is slidable in guides 334 mounted on a bracket 336. The spring 338 urges the slide 332 to the left as viewed in FIGURE 22 toward a position limited by shoulders 340. A bell crank 342 pivoted at 344 to a bracket fastened to the latch ring support post 336 is operable from the main cam drum through a rod 346 and is provided with a pad 348 urged outwardly by a strong spring 350 capable of overcoming the tension of spring 338. The link 98, previously described with reference to FIGURE 17, is pivotally connected to bell crank 328 for operation thereof by the piston rod 94.

In the operation involved in accordance with FIGURES 20, 21 and 22 control is efiected by reason of the fact that the sinkers are variably positioned by the cam 306 under the action of spring band 317 at the time the stitches are drawn, the control resulting from the positioning of portions of the ledges at diflerent heights at the locations Where they are engaged by the yarn during stitch drawing. Numerous variations may be involved as, for example, when the stitches are beingcontrolled solely from the main cam drum, by height adjustment of the needle cylinder, the automatic control is rendered inoperative in the fashions described above including the forcing upward of rod 346 which permits the sinkers to occupy their innermost position by release of the plate 320. Under these conditions, if the sinker shown in FIGURE 20 is used, the stitches will be drawn in conventional fashion over the horizontal portion 301 of the ledge. When automatic control is to occur, slide 332 is permitted to move to its extreme outer position, thereby moving the cam 306 into the range of positions wherein stitches will be drawn only on the sloping portion 364 of each sinker ledge, the needle cylinder being positioned so that, within the range of variations of engagement of ledge portion 300 by the yarn, stitches of proper size will be formed. The adjustment of cam 3% for automatic control of stitch size is effected by the action of link 98 and bell crank 323, the link 98 being operated from the pneumatic cylinder 84 in response to the stitch size detecting means as described previously.

FIGURES 23 and 24 show mechanism for efiecting stitch control by changing the position of the sinker cams with respect to the needle operating cams in a circumferential direction.

A conventional sinker cap is indicated at 354 and is provided with the usual forward and reverse bumper screws 356 and 353 en-gageable with the bracket 36!). in accordance with the invention an additional bumper screw 362 is provided. A bushing 365 has its shank 364 slidably mounted in an opening in the bracket 360 and is held against rotation by engagement of a screw 37%, acting as a key, within a slot 368 in the bushing shank. The bushing 365 is internally threaded for the reception of a screw 372 the end of which is engageaole by the bumper screw 362. At its right hand end the screw 372 has ailixed thereto a pinion 374 arranged to be rotated by a rack 3'6 which is guided for vertical movements in the machine frame. A forked lever 373 engages the head of the bushing 366 and is pivoted at 380 for operation through a link 382 connected to a cam following lever engageable by cams on the main cam drum. The rack 376 has its movements controlled from the pneumatic cylinder by the interconnecting link 98.

During periods when automatic control is not effected, the bushing 365 is released by the lever 37S, and the bumper screw 356 is then effective to determine the position of the sinker cap during movement of the needle cylinder in rundown direction either during rotary or durin reciprocatory knitting. It will be noted that the added mechanism does not interfere with the action of the screw 35% in locating the sinker cap during reverse reciprocations in reciprocatory knitting.

When automatic control is to be efiected, a cam on the main cam drum acting through link 382 forces the bushing 36% to its left-hand position so that the screw 372 is projected for engagement with the screw 352. In general, the screw 372 will be in such position that when rendered operative as just stated it will cause a counterclockwise movement of the sinker cap beyond the position determined by the normal bumper screw 356. Rotation of the screw 372 by the rack 376 controls its axial position thus adjusting the sinker cap position and, in particular, the position of the sinker projecting cam to control the knock-over action. This affects the size of stitches in the same general fashion as was involved in the operation of the modification involving FIGURE 13, with the sole difference that the time of inward sinkers movement relative to the needle Wave is controlled by circumferential displacement of a cam similar to 254 rather than its radial displacement as shown in FIG- URE 13.

Both loosening and tightening of stitches is possible through sinker cap positioning. If longer stitches are called for, the action is to move the sinker cap in a direction to cause the sinkers to be cammed inwardly slightly earlier and further than usual. Conversely, if sinker stitches that are too long are being formed, the operation is such that the sinker cap is moved so that the sinkers are moved outwardly to efiect formation of smaller sitches.

It has been found that such variable positioning of the sinker cap will cause loosening of a comparatively loose stitch as Well as a tight stitch, and accordingly, the control of this type is effective for fine adjustments of stitch size even though the major action in controlling stitch size is by reason of the relationship of the height of the needle cylinder with respect to the needle operating cams. Accordingly, determination of stitch size and fashioning may be carried out by height changes of the needle cylinder in generally conventional fashion, the control of rack 376 then providing only corrective adjustments, the wedge 188 being, of course, adjusted to correspond to the size of stitches being produced.

It will be evident from the foregoing that in accordance with the invention control of stitch size and of length of stockings may be effected in various ways, and it is therefore to be understood that the invention is not to be regarded as limited except as required by the following claims.

What is claimed is:

1. Stitch control means for a knitting machine having needles, sinkers and cam means for moving the sinkers transversely to the lengths of the needles, comprising sensing means responsive to the size of stitches produced, and means responsive to said sensing means controlling movements of said cam means, thereby to control the size of stitches being formed.

2. Stitch control means for a knitting machine having needles, sinkers, and cam means for moving the sinkers transversely to the lengths of the needles, comprising sensing means responsive to the size of stitches produced, and means responsive to said sensing means controlling the castoff movements of the sinkers, thereby to control the size of stitches being formed.

3. Stitch control means for a knitting machine having needles, sinkers and cam means for moving the sinkers transversely to the lengths of the needles, comprising sensing means responsive to the size of stitches produced, and means controlling movements of said cam means, thereby to control the size of stitches formed, the last-mentioned means comprising pneumatic motor means and controlling means therefor operated by said sensing means.

4. Stitch control means for a knitting machine having needles, sinkers and cam means for moving the sinkers transversely to the lengths of the needles, comprising sensing means responsive to the size of stitches produced, pneumatic motor means controlling the castofif movements of said cam means, thereby to control the size of stitches being formed, and controlling means for said pneumatic motor means comprising nozzle and bafile elements relatively movable by said sensing means.

5. Stitch control means for a knitting machine having needles, sinkers having sloping ledges over which stitches may be drawn, and cam means for moving the sinkers transversely to the lengths of the needles, comprising sensing means responsive to the size of stitches produced, and means responsive to said sensing means controlling said cam means to modify the sinker wave to change the relationship between the sloping sinker ledges and the needles during the drawing of stitches, thereby to control the size of stitches being formed.

6. Stitch control means for a knitting machine having needles, sinkers having sloping ledges over which stitches may be drawn, and cam means for moving the sinkers transversely to the lengths of the needles, comprising sensing means responsive to the size of stitches produced, and means for controlling said cam means to modify the sinker wave and change the relationship between the sloping sinker ledges and the needles during the drawing of stitches, thereby to control the size of stitches being formed, the last-mentioned means comprising pneumatic motor means and controlling means therefor operated by said sensing means.

7. Stitch control means for a knitting machine having needles, sinkers having sloping ledges over which stitches may be drawn, and cam means for moving the sinkers transversely to the lengths of the needles, comprising sensing means responsive to the size of stitches produced, pneumatic motor means controlling said cam means to modify the sinker wave and change the relationship between the sloping sinker ledges and the needles during the drawing of stitches, thereby to control the size of stitches being formed, and controlling means for said pneumatic motor meanstcomprising nozzle and bafile elements relatively movable by said sensing means.

8. Stitch control means for a knitting machine having needles, sinkers, and a sinker cap embodying cam means for moving the sinkers transversely to the lengths of the needles, comprising sensing means responsive to the size of stitches produced, and means responsive to said sensing means controlling the position of said sinker cap to modify the sinker Wave, thereby to control the size of stitches being formed.

9. Stitch control means for a knitting machine having needles, sinkers, and a sinker cap embodying cam means gfor moving the sinkers transversely to the lengths of the needles, comprising sensing means responsive to the size of stitches produced, and means controlling the position of said sinker cap to modify the sinker wave, thereby to control the size of stitches being formed, the last-mentioned means comprising pneumatic motor means and controlling means therefor operated by said sensing means.

10.v Stitch control means for a knitting machine having needles, sinkers, and a sinker cap embodying cam means l i for moving the sinkers transversely to the lengths of the needles, comprising sensing means responsive to the size of stitches produced, pneumatic motor means controlling the position of said sinker cap to modify the sinker Wave, thereby to control the size of stitches being formed, and controlling means for said pneumatic motor means comprising nozzle and baflie elements relatively movable by said sensing means.

References Cited by the Examiner UNITED STATES PATENTS 1,189,220 6/16 Scott 66--55 2,056,686 10/36 Mills 66-108 X 2,197,706 4/40 Peloquin 66-108 X 2,617,282 11/52 Reichert 6638 2,685,786 8/54 Stack 66-55 FOREIGN PATENTS 807,292 6/57 Germany. 526,280 9/40 Great Britain. 585,894 2/47 Great Britain.

RUSSELL C. MADER, Primary Examiner.

Claims

1. STITCH CONTROL MEANS FOR A KNITTING MACHINE HAVING NEEDLE, SINKERS AND CAMS MEANS FOR MOVING THE SINKERS TRANSVERSELY TO THE LENGTHS OF THE NEEDLES, COMPRISING SENSING MEANS RESPONSIVE TO THE SIZE OF STITCHES PRODUCED, AND MEANS RESPONSIVE TO SAID SENSING MEANS CONTROLLING MOVE-