US2938365A

US2938365A - Yarn length control means

Info

Publication number: US2938365A
Application number: US600242A
Authority: US
Inventors: Frederic H Lassiter
Original assignee: Individual
Current assignee: Individual
Priority date: 1956-07-26
Filing date: 1956-07-26
Publication date: 1960-05-31
Anticipated expiration: 1977-05-31

Description

May 31, 1560 Filed July 26, 1956 F. HILASSITER 2,938,365

YARN LENGTH CONTROL MEANS 6 Sheets-Sheet i INVENTOR:

ATTORNEYS FEEDERK. H. LASSH'ER.

May 31, 1960 F. H. A ss| TER 2,938,365

YARN LENGTH CONTROL MEANS Filed July 26, 1956 6 Sheets-Sheet 2 14 -4 a Law 4 If W Y 22 l INVENTOR: Q FREDEEIC H. LASSITER.

ATTORNEYS May 31, 1960 F. H. LASSITER 2,938,365

YARN LENGTH CONTROL MEANS Filed July 26, 1956 6 Sheets-Sheet 3 7 5k 20? INVENTOR: 2'0 I Fwenemc H. LASSITER.

-10' 1 2202 ig- Bym,w,d+ I5 901* I96 204 a ATTORNEY-S May 31, 1960 F. H. LASSITER 2,93 6

YARN LENGTH CONTROL MEANS Filed July 26, 1956 6 Sheets-Sheet 4 we (m 464 A 2 5 l- ;L '1'. .munuml lllllllllllll ll- 20 I64" T; G

Y 25 9e 2? 17 Y H 15a is? ATTORNEY 5 v INVENTOR: Fkeuemc H. LAsswE-R.

y 1950 F. H. LASSITER 5 YARN LENGTH CONTROL MEANS Filed July 26, 1956 e Sheets-Sheet s H S m H m A m E O V H n N C A m 'm H N QQ Q v8 vm 1 m .f 5 I m N am m2 k; F R N Kg lplf, E 2 91 l? 12 e: m Q .5 av w A 4 A I y I 1 a h I WWW QVI JVJ s. nm so. A .5 b ilillnk 1 l1 mom I v9. um: J

45 1, ill], 1

May 31, 1960 Filed July 26, 1956 F. H. LASSITER YARN LENGTH CONTROL MEANS 6 Sheets-Sheet 6 INVENTOR. FREuEmc '-H. LASSlTER BY ulm @al i+lkng ATTORNEYS United States Farent 2,938,365 YARN LENGTH CONTROL MEANS Frederic H. Lassiter, 527 Lexington Ave, New York, NY. Filed July 26, 1956, Ser. No. 600,242

Claims, (c1. 66-132) This invention relates to an improved apparatus for controlling the length of yarn and other strand material in its course of travel from a source to apparatus having a demand for it, such as a knitting machine. The present invention is particularly concerned with improvements in apparatus of the type disclosed in my co-pending application, Serial Number 486,530, filed February 7, 1955, and entitled Yarn Tension Controlled Yarn Feeding Apparatus, now Patent No. 2,838,923, of which the present application is a continuation-impart.

It is an object of this invention to provide improved means for controlling the length of yarn or other strand material and, incidentally, to control the tension therein as the yarn is drawn from a source to a take-up means, such as a circular knitting machine, wherein the yarn passes from its source in engagement with a rotary member or between a pair of yarn-feeding rotary members which are driven by a pneumatically-operated variablespeed drive or device.

The yarn is then formed into a loop which is lightly engaged by a sensing element and, thence, the yarn passes to the take-up means. The sensing element is connected with an air pressure controller in a pneumatic circuit to a variable-speed drive or device and responds to the slightest movement of the sensing element so the rotary members' are driven at a speed exactly proportional to the speed at which the yarn is demanded or taken up by the take-up means with the result that the yarn can be maintained under a lesser tension between the rotary members and the take-up means than the tension in the yarn between the source and the rotary members.

It is another object of this invention to provide an apparatus of the character last described which is compact, simple to construct and easily maintained and which includes a relatively few parts as compared to the apparatus disclosed in said co-pending application.

It is still another object of this invention to provide an apparatus of the character described wherein the variable-speed device is driven by the machine having the demand for the yarn so that the variable-speed drive is controlled both by the machine and by the sensing element.

Some of the objects of the invention having been stated, other objects will appear as the description proceeds when taken in connection with the accompanying drawings, in which- Figure 1 is a somewhat schematic rear elevation of a circular knitting machine showing the improved yarn control apparatus mounted thereo'rl;

Figure 2 is a fragmentary elevation looking at the leftharid side of Figure 1, omitting the cover on the gear.

box or transmission unit which transmits rotation from the knitting machine to the variable-speed drive or transmission; i

Figure?) is an enlarged firagmentary sectional plan view taken substantially along line 3-3 in Figure 2;

' Figure 4 is an enlarged front elevation of the im- 2 proved control apparatus, looking at the opposite side of the same from that shown in Figure 1;

Figure 5 is an enlarged elevation, partially in section, taken substantially along line 5-5 in Figure 4';

Figure 6 is an end elevation of the yarn length control apparatus looking substantially along line 6-6 in Figure 4, this being the opposite end of the main housing from that shown in Figure 5; i i

Figure 7 is an enlarged longitudinal vertical sectional view taken substantially along line 7-7 in Figure 5, through the primary control unit of the improved apparatus, particularly showing the air bleeder port or orifice and the adjacent control valve carried by the sensing element; 7

Figure 8 is an enlarged plan view of the improved yarn length control apparatus looking along line 8-8 in Figure 4 and showing the same removed from the kntting machine; A

Figure 9 is a front elevation of the control apparatus, partially in section and with the main cover broken away, taken substantially along line 9-9 in Figure 8 Figure 10 is an enlarged fragmentary vertical sectional view taken substantially along line 10-10 in Figure 9 to illustrate the air metering valve for the pneumatic circuit;

Figure ll is a view similar to Figure 8 with the upper portion of the 'main cover of the main housing broken away;

Figure 12 is a rear view of the yarn length control apparatus looking at the opposite side thereof from that shown in Figure 9 with the rear cover of the housing removed and showing, schematically, a valve interposed in the pneumatic circuit for controlling the position of one of the rotary yarn feeding elements relative to the other;

Figure 13 is an enlarged sectional plan view of the apparatus taken substantially along line 13-13 in Figure 9;

Tigure 14 is a vertical sectional view through a pneumatic relay taken substantially along line 14-14 in Figure l3;

Figure 15 is an enlarged elevation, partially in section, taken substantially along line 15-15 in Figure 9;

Figure 16 is a schematic illustration of a pneumatic circuit for the improved apparatus.

Referring more specifically to the drawings, the numetal 1'!) designates a source of randomly tensioned yarn Y, which source is shown in the form of a pirn mounted on a package holding bracket or rack 11 extending rearwardly from a machine having a demand for the yarn Y, which machine is shown in the form of a circular knitting machine broadly designated at 12 (Figures 1, 2, 3 and 4). In this instance, the bracket 11 is fixed to the lower portion of a stationary post 13, an upper portion of which has a bracket 14 fixed thereto for supporting a main housing 15 which carries the improved variable-speed drive or transmission for feeding yarn as will be later described.

It might be stated that the pirn 10 (Figures 1 and 4) is of the usual type type received from the manufacturer of the yarn Y. The yarn Y may be a synthetic yarn, such as nylon or the like, as wound on the pirn by the manufacturer with little or no regard for the manner in which the yarn is laid onto the pirn or the shape of the yarn package on the pirn. Various convolutions of the yarn lay across others, the shape of the package is not uniform and the tension in adjacent convolutions may vary considerably. Heretofore, the yarn Y on the pirn 10 had to be rewound, under uniform tension, onto a cone or other yarn carrier before it could be used with circular knitting machines such as the type illustrated in Fi ures 1, 2, 3 and 4. Many knitting plants are not rotary feeding means, as embodied in a pair of gears 16, a

17, and the knitting machine 12, eliminates rewinding of the yarn so the yarn may be drawn directly from the pirn, on which it was wound by the manufacturer, to the knitting machine.

The yarn Y extends upwardly from. the pirn in Figures 1 and 4 and passes through a pair of

yarn guides

20, 21 carried by the housing and then downwardly between the rotary elements or

gears

16, 17 which are driven by the improved variable speed transmission to be later described. The yarn Y passes downwardly from the

gears

16, 17 to engage a yarn length sensing element or detector which is shown in the form of a yarn guiding eye 22 formed in the free end of a sensing lever broadly designated at 23. The sensing lever 23 is a part of a primary controller or control unit broadly designated at 24.

The yarn passes upwardly from the eye 22 of the sensing lever 23, to form a loop as the yarn is drawn through a suitable yarn guide 26 carried by the housing 15. The yarn Y then extends from the yarn guide 26 over a guide roller 27 journaled on a bracket 30 carried by the post 13. A yarn tension device may be substituted for the roller 27, if desired. The yarn Y then extends downwardly through the usual yarnfeed fingers 31 and other knitting instrumentalities of the knitting machine 12. The knitting machine 12 is representative of any type of yarn consuming or take-up means, but is illustrated herein since it is with machines of this type that most difliculties are encountered in controlling tension in yarn as it is directed to the knitting instrumentalities, particularly in the knitting of ladies seamless hosiery.

The knitting instrumentalities include the usual needle cylinder 32 which is driven to, at times, rotate and to, at other times, reciprocate, by means of conventional gearing generally designated at 33. Included in such gearing is a gear 34 which is driven constantly, in one direction, at a speed in direct proportion to the rate of rotation or reciprocation of the needle cylinder 32. This gearing also controls movement of a conventional pattern mechanism such as a pattern chain 35.

Although the improved variable-speed driven mechanism may be provided with its own motor, the extent to which the variable speed mechanism can vary the speed of the yarn feeding rollers or gears 16, 17 is preferably limited so as to maintain compactness in the size of the variable speed mechanism and to also minimize the extent of movement of the sensing lever 23. Accordingly, the improved variable-speed mechanism is driven at a speed in direct proportion to the speed of the gearing 33 of the knitting machine, since it is well known that the gear 34 will rotate at a relatively slower speed during reciprocatory movement of the needle cylinder 32 as compared to its speed during rotary movement of the needle cylinder 32.

In this instance, a pinion 29 meshes with the gear 34 (Figures 2 and 3) and is fixed on a shaft 36 journaled in a housing or gear box 37 carried by the frame of the knitting machine 12. The shaft 36 also has a gear 40 fixed thereon which meshes with a pinion 41 fixed on a shaft 42 also journaled in the housing 37. One end of shaft 42 has a flexible cable 43 connected thereto which flexible cable extends through a flexible-housing 44 connected .to the gear housing 37.

As best shown in Figure 13, the end of the flexible cable 43 remote from the gear box 37 is connected to the outer or rear end of a drive shaft 46, as bybeing keyed thereto, and the corresponding end of the housing 44 for the flexible cable 43 is attachedto the outer end of a bearing bracket 47 by means of a gland nut 50. The bearing bracket 47 is suitably secured to the rear surface of a main support plate 51 which forms the rear wall of the main housing 15. The shaft 46 is journaled in the bearing bracket 47 as by means of a pair of spaced ball bearings or antifriction bearings 52. The drive shaft 46 extends forwardly through an opening 53 formed in plate 51 and has a pulley 54 mounted thereon which is engaged by an endless belt 55.

The pulley 54 is preferably of the manually adjustable 1 variable-pitch type as shown in Figure 13 so the optimum output speed of the variable-speed drive or transmission, of which pulley 54 is a part, may be predetermined to where the detecting lever 23 will occupy a substantially neutral position when the yarn Y is being delivered by the

gears

16, 17 at a speed substantially equaling the most preponderant demand for the yarn by the knitting instrumentalities.

To this end, the adjustable pitch pulley 54 comprises a fixed flange 56 which is fixed on the shaft 46 and has a hub 57 thereon on which an adjustable flange 6 0 is threaded, the adjustable flange 60 being locked in position on the hub 57 by means of a lock nut 61. The driving pulley 54 and belt 55 transmit rotation to a driven variable-speed or expansible pulley broadly designated at 62.

The driven pulley 62 comprises a fixed flange 63 which is fixed on a shaft 64 and has a hub 65 on which an axially movable flange 66 is keyed, as at 67. The front or outer flange 66 is urged toward flange 63 by a compression spring 70 whose inner end bears against the flange 66, and whose outer or front end bears against a collar 71 adjustabl-y secured on the shaft 64, as by a set screw 72.

Reduced opposite end portions of shaft 64 are journaled in respective bearing blocks 73, 74, preferably by means of respective antifriction or ball bearings 75, 76. It will be noted that the support plate 51 has an opening 77 therein through which the shaft 64 extends to the bearing block 73. The bearing block 73 is suitably secured to the rear surface of the plate 51. The bearing block 74 is shown in Figures 9, 11, 13 and 15 in the form of a plate which is suitably secured to the outer ends of a plurality of spacing members or rods 80, as by'nuts 81. The inner or rear ends of the rods 89 are suitably secured to the support plate 51, as by being threaded thereinto. The front end of the shaft 64 extends through an opening 82 formed in the front wall 83 of the housing 15. In the present instance, the front wall 83 is formed integral with a top wall 84, a bottom wall 85 and

opposed end walls

86, 87 and these Walls '83 through 87, collectively, form a main cover which is removably secured to the support plate 51. The lower portion of the plate 51 preferably has a pair of downwardly projecting substantially L-shaped portions or legs 90 integral therewith for securing the main housing 15 to the bracket 14, the horizontal portions of the legs 90 being secured to the bracket 14, as by screws 91 (Figures 1, 2, 4 and 5).

Referring again to Figure 13, it will be observed that: the reduced front portion of shaft 64 has a spacing sleeve 95 loosely mounted thereon whose rear end bears against the inner race of the ball bearing 76 and whose outer end is engaged by the rear surface of the first yarnfeeding gear 16, the gear 16 being held against the sleeve 95 bymeans of a nut 96 which is shown in the form of an acorn nut in Figure 13. The reduced rear end of the shaft 64-also, has a gear 97 mounted thereon which is preferably fixed on the reduced rear portion of shaft 64 by means of spacing sleeves or collars 100 and a nut 101. The gear 97 meshes with a similar gear 102 which is fixed on the reduced rear end of a shaft 103,

preferably by means such as that employed in securing block 104 suitably secured to the rear surface of a secured to the rear surface of the support plate 51.

assesses pivoted or shiftable bracket 106, an antifriction or ball bearing 105 preferably being used for mounting the reduced rear portion of shaft 103 in the bearing block 104.

The body of the pivoted or shiftable bracket 106 is of hollow construction and extends through an opening 107 formed in the support plate 51. The forward. portion of bracket 106 terminates short of the front wall '83 of housing and has the reduced-forward portion of shaft 103 journaled therein, preferably -:by means of an antifriction or ball bearing 110. .It will be observed in Figure 13 that the secondary gear 17, which normally meshes with the primary gear 16, :is mounted on the forward portion of the shaft 103 in the same manner as that in which the gear 16 is mounted on the reduced forward portion of shaft 64, the front wall 83 of housing 15 being provided with an opening 111 corresponding to opening 82, a spacing sleeve 113 corresponding with sleeve '95, and a out 114 corresponding with the nut 96. In order to prevent lint and other foreign matter from entering the housing 15, it is preferable that the walls of the openings 82, 111 in the front wall 83 fiare outwardly and are substantially semi-circular in cross-section, as shown in Figure 13, and terminate in closely spaced relation to the bottoms of annular recesses 116, 117, formed in the rear surfaces of the respective primary and secondary yarn feeding gears or

rollers

16, 17.

It will be observed in Figure 9 that the right-hand side of the front bearing block or plate 74 is cut away to form a recess 120 therein to accommodate the for- 'ward portion of the shiftable bracket 106. The rear wall of the shiftable bracket 106 is provided with a pair of rearwardly projecting upper and lower lugs 121, 122 which are substantially L-shaped in plan (Figures 11, 13 and 15) and which straddle the gear 102. The free ends of the lugs 121, 122 are pivotally mounted on a substantially vertically disposed shaft 123 which is disposed in off-set relation to the axis of the shaft 103 and which is preferably disposed in substantial alinement with the junctures of the

gears

16, 17 and 97, 102. The upper and lower ends of the shaft 123 are fixed in rearwardly projecting

lugs

124, 125 integral with or suitably The secondary yarn delivering gear 17 is normally resiliently urged into engagement withthegear 16 by means of a tension spring 130 (Figures 11 and 12), the rear end of which is connected to a plate 131 suitably secured to the upper surface of the lug 121, as by screw 132 (Figures 11 and 13). The front end of the spring 130 is connected to the support plate 51.

Since many yarns, particularly synthetic yarns, are extremely fine, the teeth on the yarn feedinggears 1-6, 17 should be ground and polished and devoid of sharp edges, and it may be desirable to space the

gears

16, 17 slightly in the feeding of some types of yarns. Accordingly, an abutment may be provided to limit the extent to which the shiftable bracket 106 is urged in a clockwise direction in Figures 11 and 13 by the tension spring 130. Such abutment is shown in Figures 11 and 15 in the form of a set screw 135 which is threaded through the plate 51 and is locked in the'desiredposition by a lock nut 136. The set screw 135 is alined with the down-turned outer end of the plate 131 so the spring 130 normally maintains the plate 131 in engagement with the rear end of the screw 135 and, consequent- 1y, determines the displacement between the proximal surfaces of the

gears

16, 17.

It sometimes becomes necessary to operate the knitting machine 12 without feeding yarn to the knitting instrumentalities and, also, during reciprocatory knitting in forming the heel pocket and toe pocket of a stocking, for example, the maintenance of proper yarn length and consequent yarn tension is not as critical as it is during .rotar-yknitting. In the latter instance, :it might be desirable, from a standpoint or cost, to omit the gear box 37 and its .gearing and to substitute an electric motor or other suitable means for driving the drive shaft 36 at a speed such as to deliver the yam Y to the knitting .instrumenta'litie's at "a speed corresponding only to the high speed requirements of the machine.

- Regardless of whether the drive shaft 46 is driven by the means shown in the present drawings or by any other means, in the event of the machine 12 being operated and it is desired that 'theyarn Y is not taken up by the knitting instrumentaliti'es, it may be desirable 'to move the secondary yarn feeding gear 17 out of engagement with the primary-gear .16 so the gear 16 will not feed the yarn, or so the yarn Y is not withdrawn from the source .10, although the gear :16 may continue to rotate.

There are various means which may be used to shift the bracket 106 in order to shift the gear 17 out of engagement with the gear 16 and, in the preferred embodiment of such means, a fluid pressure operated ram or piston rod 1401s providedKF-i'gures ll, 15 and 16) whose free rear end is normally spaced closely adjacent the front surface of an angle clip or abutment 141 suitably secured to or formed integral with the plate 131. The piston rod 140 extends forwardly and loosely penetrates the plate 51 and is connected to a diaphragm or piston 142 mounted in a cylinder 01' diaphragm housing 143. A compression spring 144 normally urges the piston 142 and piston rod 140 to retracted or inoperative position as shown in Figure 15. Thefront end of the cylinder 143 has one end of a conduit 146 connected, as by a pipe T 147-, to a main airpipe 150, one end of which is connected to a suitable source of compressed air, not shown, preferably at fifteen pounds per square inch.

A suitable two*Way'valve-151 is interposed in the conduit 146, which 'valvemay be either manually or pattern controlled, or both, for controlling the position-of the secondary yarn feeding gear 17 relative to the primary yarn feeding gear 16 for the purposes heretofore described. It is apparent, that upon the valve 151 being opened, the compressed air flows into the cylinder 143 and causes the piston rod 142 to engage the angle clip 141 to thereby shift the bracket 106 in a counterclockwise direction in Figures 11 and 13 and, when the valve- 1511s closed, air is exhausted from the cylinder 143 as the spring returns the gear 17 to operative position.

The variable-

speed transmission

54, 55, 62 is preferably driven by the knitting machine because of the intervals which transpire from the time of starting the machine to that in which the speed of the machine has built up to normal. However, it is often desirable to automatically render the yarn length control inoperative at certain intervals. To this end, the valve 151 may be positioned adjacent the pattern chain 35 as shown in Figure 2. The pattern chain 3:5 has one or more projections 152 thereon for engaging and opening the valve at desired intervals such as in knitting the heel and toe pockets of a stocking.

It might be stated that the driving gears 97, 102 on the rear ends of the

shafts

64, 103 could be omitted, but these gears are of the same size and have the same size and number of teeth thereon as the

gears

16, 17, in order to insure that the teeth in the gears 16, 17'will mesh properly any time that the. gear 17 .is returned to operative position after having been-moved to inopera tive position in the manner heretofore described.

In order to control the speed of the yarn feeding-

gears

16, 17 so they feed the yarn-Y at a rate proportional to the rate at which the yarn is taken up andwhile also maintaining a predetermined length of yarn between the

gears

16, 17 and the knitting instrumentalities or, at least, between the

gears

16, 17 and the yarn tension;d evice 27 if such is used, the primary control1er 24, -responds to the variations in position of the seusing'leycr 23 to controls speed regulator broadly designated at 155 which, in turn, controls the tension in the endless belt 55,. it being apparent that the greater the tension applied, to said belt 55, the greater the speed of the gear 16 due tov the expansible or variable speed pulley 62. The primary controller 24 operatesunder a substantially lesser pressure thanline pressure primarily for the purposeIof'conservingcompressed air, although the primary controller could be.v operated under full head pressure. Since a knitting plant is usually equipped with a substantial number of knitting machines and one or more of the, improved yarn'length control apparatuses would be used on each of such machines and, since the compressedair is exhausted from the primary controller, as will be later described, it is desirable that a minimum of compressed air be used to operate the primary controller so that the volume of compressed air used for operating a large, number of such apparatuses would not exceed the normal capacity of compressors usually used head, respectively. The cylinder base 157 has one end of a'conduit 161 connected thereto for communication with the interior of the cylinder 156 and a cup-like piston 162 is mounted for longitudinal movement in the cylinder 156. In order to facilitate ease of movement of the piston 162 longitudinally of the cylinder 156, due to the relatively low air pressures used to operate the same, the piston 162 engages a rolling diaphragm or pliable seal 163 which is connected tothe head member 158 as by screws 164 which penetrate the cylinder, the diaphragm 163 and a reduced portion of the head member 158 which fits within the diaphragm 163 as clearly shown in Figure 7.

Thediaphragm 163 and the piston 162 have one end of. a piston rod 165 suitably connected thereto whichloosely penetrates the head member 158 of cylinder 156 as well as a controller support plate 167 and a shield support plate 170. The

plates

167, 170 and cylinder head 158 may be formed integral with each other or may be suitably interconnected asshown in Figure 7. The controller support plate 167 is connected to the substantially horizontal leg of an L-shaped bracket or 4 rod 171 whose vertical leg extends upwardly and is fixed in a projection 172 on the rear portion of the support plate 51 of the main housing 15, as by a set screw or thumb screw 173 (Figures 5, 8, 9, 10, ll, 12 and 13).

Referring again to Figure 7, it will be observed that the piston rod 165 is encircled by a spring 174 which normally urges the piston 162 and rod 165 to the left or to retracted position. The end of the piston rod 165 opposite from the piston 162 is pivotally connected, as at 175, to a bifurcated arm of a bell crank 176, opposed side portionsof the bell crank 176 being oscillatably mounted on respective pivot shafts 177 (Figure 13) whose outer orldistal portions are threaded through lugs 180 which forma substantially U-shaped' bracket attached -to the shield support plate 170, or the lugs 180 may be formed integral with the support plate 170.

The pivot shafts 177 are each held in the desired adjusted position by a lock nut 181, and a rigid extension 182 of the sensing lever 23 is pivotally supported by the pivot shafts 177. In'order to minimize frictional resistance to movement of the lever 23 relative to the bell crank"176 and the pivot shafts 177, it is preferable that the pivot shafts 177 are each provided with a pointed projection 184, and these pointed projections fit in suitable seats provided on opposite sides of a medial portion of the lever extension 182.

' The sensing lever 23 also includes a main body portion 185 whichT-is preferably made from a very light weight material, such as fine wire or plastic, and in the free end of which the eye 22 is formed, the other end of the body portion of the sensing lever 23 being suitably attached to the outer end of the extension 182. The body portion 185 of lever 23 loosely penetrates a slot 186 formed in the end of a cup-like shield 187' which fits about the plate 170 3114 houses the bell crank 176 and adjacent partse" In-order to limit downward movement of the free end of the. sensinglever 23 relative to the bell crank 176, the bifurcated portion of the bell crank 176 at the juncture of the two'arms thereof is provided. with a stop or abutment 188. The free end of the upper arm of the bell crank 176 is provided with a rigid plate portion 190 in which a throttling valve, pilot valve or nozzle 191 is adjustably secured, as by being threaded therethrough. The throttling valve 191 is of hollow construction to form an air exhaust orifice a in its lower end, which orifice is adapted to be restricted by a valve restrictor or closure member b attached to or formed in,- tegral with the rigid extension 182 of the sensing lever 23. The throttling valve 191 is locked in the desired position by means of a lock nut 193 (Figures 7 and 13).

One end of a flexible conduit 194 is connected to the valve 191 for communication with the interior thereof and the other end of the flexible conduit 194 is connected,

as by a pipe T 195 attached to the

plates

167, 170, to

'a metering valve body 203 which also has one end of a conduit 204 extending therefrom through plate 51 andconnected to the main air conduit 150 .by means ofa pipe T or fitting 205 (Figures 12 and 16).

The metering valve body 203 is best shown in Figure 10 wherein it will be observed that the valve body 203 is suitably secured to the front surface of the plate 51.of f

the main housing 15 as by screw 206. The

conduits

200, 204 communicate with respective passageways or chambers 0, d formed in the metering valve body 203, and a metering valve or needle valve 207 is a djustably mounted in the valve body 203, as by means of being threaded thereinto. The metering valve 207 is adapted to restrict the flow of compressed air from the chamber or passageway d into the passageway or chamber 0.

Referring now to Figures 9, ll, 13 and 16, the speedregulator comprises a fluid-pressure-operated or compressed-air-operated ram 210 which is shown in the form of a piston rod pivotally connected to one end of a lever or arm 211 oscillatably mounted, as at 212, on a projection,2 13 formed integral with, or suitably secured to, the front surface of the plate 51 of main housing 15. The free end of the lever 211 is provided with a tension roller 214 (Figures 9, 11 and 16) which bears against the upper surface of the upper reach of the endless belt 55 of the variable speed drive mechanism. V

A piston rod 210 loosely penetrates the head of a cylin der 220 in which a piston 221 and a rolling diaphragm or pliable seal 222 is positioned in substantially the'same manner as that described with respect to the piston 162 and rolling diaphragm 163 in Figure 7, The inner end of the piston rod 210 is suitably secured to the piston 221 and diaphragm 222 and is normally urged down wardly or inwardly by means of a compression spring 223. The cylinder 220 is fixed to the front surface of the support plate 51 of the main housing 15 by means of a bracket 224 and screws 225 (Figure 13). It, is apparent that the driver pulley 54, its motive means and shaft 46 (Figure 13) may be mounted for adjustment toward and away from pulley 62 in a well-known manner, and

adjusted by means similar to regulator 155 to vary the Now, if so desired, a conduit could connect the lower end of the cylinder 220 with the conduit 201 to cause the speed regulator 155 to respond to the primary controller 24. However, since the metering valve 207 permits only a relatively small amount of compressed air to flow into the

conduits

196 and 201 in a given relatively short interval, the response of the speed regulator 155 to variations in the relative positions of the orifice a of valve 191 and restrictor b of the primary controller 24 (Figure 7) would be so slow as to impair the efiiciency of the improved yarn length control apparatus.

Therefore, one end of a conduit 230 is connected to the lower end of the cylinder 220 of speed regulator 155 for communication with the interior of said cylinder 220 and this conduit, and the

conduits

150 and 201 loosely penetrate the support plate 51 and are connected to a pneumatic relay or booster broadly designated at 232 which may also be termed as a secondary controller. The relay 232 comprises a body 233, a first flexible diaphragm 234, a hollow spacing member 235, a second fiexible diaphragm 236 and a closure member or cap 237, all of which are serially arranged and suitably secured together, as by screws 240 (Figures 11 to 16, inclusive).

Referring to Figures 13 and 14, the rear surface of the body 233 of relay 232 is provided with a recess forming a main air transmission chamber C1 in front of the diaphragm 234. The annular spacing member 235 forms an intermediate or latent air chamber C2 between the

diaphragms

234, 236 and the front surface of the cap 237 is provided with a recess which forms a pilot air chamber C3 in back of the diaphragm 236. It will be observed in Figure 14 that the relay 232 is provided with a passageway 240 which communicates with the pilot air chamber C3, extends through the

diaphragms

234, 236 and the spacing member 235, and communicates with the conduit 201, which conduit is suitably connected to the body 233 of the relay 232.

The body 233 of the relay 232 has a valve chamber C4 therein in which a main air valve M, shown in the form of a ball, is loosely positioned. The main air valve M is normally urged against'its seat S by a compression spring 241. The body 233 of relay 232 is also provided with a passageway P which is of lesser diameter than, and communicates with, the valve chamber C4 and has an externally fluted end. portion of a tubular valve actuator T loosely mounted for axial movement therein. The actuator T also serves as an exhaust valve.

The front end of the valve actuator T bears against the rear surface of the main valve M and its rear portion is attached to the primary diaphragm 234 and a block 242 which is shown as being of built-up construction in Figures 13 and 14 and whose distal surfaces engage the proximal surfaces of medial portions of the

diaphragms

234, 236. The rear end of the tubular actuator T terminates short of the rear end of the block 242 and the block 242 has a lateral air discharge passageway P2 therein for maintaining communication between the tubular actuator T and the interior of the latent chamber C2. The annular spacing member 235 is provided with a radially extending exhaust port P3 to exhaust air. from the main. air chamber C1 Whenever the pressure in the main air chamber C1 is sufficiently greater than the pressure in the pilot air chamber C3 to cause the tubular actuator T to move rearwardly away from the main air valve M.

It will be observed in Figure 13 that the conduits 2.50, 230 are connected to opposite sides of the body 233 of the relay 232 and communicate with respective passagewaysP4,'P5 formed in the body 233. The passa eways P4, P5, in turn, communicate with the valve chamber C4 and the main air chamber C1, respectively.

The pneumatic relay 232 maybe supported in any desired manner and it will be observed in Figures 12, 14 and '15 that the front surface of the body 233 is fixed to the rear portion of a bracket 245 which extends down- 'wardly and then forwardly and again downwardly and is suitably secured to the rear surface of the plate 51 of the main housing 15 at a point below the lug which supports the shiftable bracket 106., A cup-like rear cover 246 is removably connected to the rear sur, face of the main support plate 51 for enclosing the rela 232, gears 97, 102 and associated parts.

Method of operation It is preferable that the sensing lever 23, particularly the body portion 185 thereof, applies only a very slight downward pressure against the yarn Y passing through the eye 22 thereof, particularly when the pirn 10 has a relatively fine denier monofilament synthetic yarn wound thereon, so that the sensing element 23 applies very little pressure against the yarn and creates substantially lesser tension in the portion of the yarn forming the loop than the tension normally present in that portion of the yarn extending from the source or pirn 10 to the yarn feeding gears or

rollers

16, 17.

Assuming the knitting machine 12 is not operating and that the valve 151 is closed so the parts of the yarn length control apparatus occupy substantially the position shown in Figures 1, 4, 7, 9 and 12, and also assuming that main air is entering theconduit at a constant pressure of, say, fifteen pounds per square inch, the knitting machine 12 is then started to initiate rotation of the yarn feeding gears 16, 17 by means of the gearing shown in Figures 2 and 3, the flexible cable 43 in the housing 44 and the variable-speed transmission free end of the lever 211 of the speed regulator 155 occupies raised or inoperative position so the endless belt 55 is under minimum tension. The speed of the knitting machine needle cylinder 32 relative to the speed of the gear 16 is such that, when the speed regulator lever 211 occupies said inoperative position, the gear 16 and, of course, the gear 17 would rotate at a relatively slow speed such as to tend to feed the yarn Y at a rate less than that meeting the demands of the knitting instrumentalities. Thus, as the knitting machine is's-tarted, the sensing element or lever 23 is raised or moved in a counterclockwise direction in Figures 4, 7, 9 and 16, as the yarn Y tends to straighten out as it is consumed by the knitting machine, to move belt tensioning roller 214 downwardly as will be presently described.

As the sensing lever 23 moves upwardly in Figure 7, the valve restrictor b of the primary controller 24 moves toward the orifice a of the throttling valve 191 and either closes the same or, at least, substantially restricts the size thereof to thereby reduce the rate at which compressed air is exhausted through the orifice a. It might be stated that, with normal fluctuations of the sensing element 23, the restrictor never actually engages the .valve 191. It is apparent that, by referring to Figures 7 and 16, compressed air is normally exhausted through the orifice a because main air flows into the reducing valve body 203 from the main air conduit 150 through conduit 204, and the needle valve 207 (Figure 10) restricts flow of air through the metering valve body 203 so a lesser volume of air enters the

conduits

201, 202. It is apparent that the conduit 1% and conduit 194 direct the air at reduced volume into the throttling valve 191.

It might be stated that the orifice a of the throttling valve 191 not only exhausts compressed air from the conduit 196, but it also exhausts compressed air from the cylinder 156 of the primary controller 24 and from the pilot chamber C3 (Figure 14) of the pneumatic relay 232. The closer the restrictor b is positioned on the sensing lever 23 to the orifice a with consequent greater restriction of the orifice a, the greater the pressurein the

conduits

196, 201, so the proximity of the restrictor b to 'the orifice a (Figure 7) determines the air'pres sure which is present in the cylinder 156 of the primary controller 24 and the pilot chamber C3 in the relay 232 (Figures 13 and 14). a V I It follows therefore that, as the knitting machine 12 is started and the sensing element or lever 23 is suddenly moved upwardly by the bight of the yarn loop, the amount of air in the cylinder 156 of the primary controller 24 and in the chamber C3 increases so the piston 162 in cylinder 156 moves from left to right in Figure 7 to impart movement to thethrottling valve 191 thereby tending to move the same with and in the same direction as the restrictor b until the'amount of yarn present between the yarn feeding gears 16,17 and the knitting instrumentalities increases to return the sensing lever to a substantially neutral position. The latter position is preferably substantially midway of the arc of travel of the free end of the sensing lever 23.

As the sensing lever 23 moves downwardly in the manner last described, the-eifective size of the orifice a is consequently increased so that at least some of the air in the cylinder 156 is exhausted and so the spring 174 moves the throttling valve 191 downwardly until it assumes a predetermined position in close proximity to the restrictor b.

It is apparent that the sensing lever 23 moves downwardly after having been raised, because of the speed of the gears or

rotary elements

16, 17 being increased a predetermined amount, such increase inspeed being effected 'by the increase in pressure in the pilot chamber C3 of 'the pneumatic relay 232, as will be presently described. Conversely, in the event of the speed of the yarn feeding gears 16, 17 being increased to where the loop formed from the yarn Y becomes abnormally large, the sensing element or lever 23 is permitted to move downwardly thereby to where the restrictor 1: permits a greater than normal amount of air to be discharged from the orifice a of the throttling valve 191. It is apparent that .this decreases the amount of air in the pilot chamber C3 of the pneumatic relay 232 to correspondingly decrease the speed of the yarn feeding gears 16, 17 as will also be presently described.

Now, as the knitting machine 12 is initially started, it is to be assumed that the pressure of the air in the main air chamber C1, the speed regulator cylinder 220, the intervening conduit 230 and passageway P (Figures 13 and 14) is substantially at zero pounds per square inch or, at least, the pressure in the chamber 01 and the cylinder 220 of the speed regulator 155 is sufiiciently low so that the spring 241 (Figures 13 and 14} holds the main air valve M against the valve seat S and the spring 223 of the speed regulator 155 (Figures 13 and 16) maintains the lever 21 1 and its roller 214 in inoperative position. Accordingly, with the sudden increase in pressure in the pilot chamber C3, as effected by the sudden upward movement of the sensing lever 23, .the pressures in the chambers C1, C3 are thrown out of balance so the diaphragm 236 moves the block 242, diaphragm 234, tubular valve actuator T and the valve M from right to left in Figure 14 or downwardly in Figure 13.

This moves the valve M off the seat S and permits main air to flow from the conduit 150, through the passageway P4 in the main body 233 of the relay 232, through the valve chamber C4, through the passageway P past the actuator T and into the main air chamber Cl. From the main air chamber C1, main air flows through the pas-asgeway P5 and the conduit 230 to the lower end of cylinder 220 of the speed regulator 155 to thereby move the piston 221 and piston rod 210 upwardly and to correspondingly move the roller 214 downwardly to apply a predetermined amount of tension to the endless belt 55 which, of course, proportionately increases the speed of the yarn feeding gears 16, 17.

.The free end of the lever 211 and the roller 214 continue to move downwardly until theair pressures in 12 the chambers C1, C3 are such that substantially the same balancing force exists on the

diaphragms

234, 236.

'In this connection, it should be noted that the main air chamber C1 is substantially smaller than the pilot chamber C3 to compensate for the spring 241 and other restricting elements in chamber Cl. It is thus seen that,

'through the mediumofthe pneumatic relay 232, the position of the lever-211 andthe throttling valve is determined bypilot air pressure as determined by the relative positions of the valve 191 and the restrictor b.

Now, as the restrictor b moves from an optimum position relative to the orifice ajot the throttling valve 191 away from the same, this reduces the amount of air in the pilot chamber C3 of the pneumatic relay 232 so that a greater eiiective pressure momentarily exists in the main air chamber C1 and the speed regulator cylinder 220. It is "apparent that the pressure in the main air chamber C1 then causes the

diaphragms

234, 236, the block 242 and the actuator T to move from left to right or rearwardly in Figure 14 so the front end of the actuator T is moved away from the valve M as the valve M engages its seat 8. When this happens, actuator T moves away from valve M so air is exhausted from the speed regulator cylinder 220 through the conduit 230, and passageway P5 (Figure 13) into main air chamber C1, as it is exhausted from the latter chamber through the passageway P (past the front portion of the actuator T) and then through the main valve actuator T, the

passageway P2, the intermediate chamber C2 and the exhaust port P3, to the atmosphere.

As air is exhausted from the cylinder 220 of the speed regulator 155, it is apparent that the spring 223 moves the lever 211 in a counterclockwise direction in Figures 9 and 15 a predetermined amount, in accordance with the amount of air exhausted from the cylinder 220, to correspondingly reduce the speed of the yarn feeding gears 16, 17. When the efiective pressure in the chambers C1, C3 are again balanced, the

diaphragms

234, 236 return to neutral position to seat the front end of the tubular valve actuator T against the ball M to complete a cycle in the operation of the improved yarn length control apparatus.

It is thus seen that, upon the pressure in the pilot chamber C3 being increased above a predetermined optimum by movement of the sensing lever 23 above a predetermined optimum position, the speed of the

gears

16, 17 is momentarily increased and, whenever the pressure in the pilot chamber C3 is reduced below a predetermined optimum, due to the movement of the sensing lever below a predetermined optimum position, the speed of the

gears

16, 17 is momentarily reduced below a predetermined optimum speed. Thus, in effect, the sensing element 23 changes or varies the speed of the yarn feeding gears 16,17 with very slight movement of the element 23 from any medial position to each of a plurality of other positions in either direction.

In order to insure that the throttling valve 191 and restrictor b tend to occupy neutral positions, the relative sizes of the

pulleys

60, 62 in Figures 9 and 13 are such that the optimum demand of the knitting machine for the yarn Y is met when the lever 211 and its roller 214 occupy neutral position, i.e.; when the lever 211 and its roller 214 are midway between high and low position, or when the belt 55 is positioned substantially midway between high and low speed positions.

This is effected by means of the

springs

174, 223 in the

respective cylinders

156, 220, which springs are so calibrated that movement of the throttling valve 191 in either direction causes corresponding movement of the lever 211 in either direction. Movement of the throttling valve 191 is effected, in relation to movement of the lever 211, by variations in pressure in the cylinder 156 as effected by the extent to which the restrictor b restricts the orifice a in thethrottling valve 191. .In other c eeses words, it is assumed that approximately two pounds of pressure per square inch are required in order to overcome the resistance of spring 174 and initiate movement of the piston 162 in cylinder 156 of the control unit 24 from left to right in Figure 7. Thus, the restrictor b must move in sufficiently close proximity to the orifice a in order to provide a minimum pressure oftwo pounds per square inch in the left-hand end of the cylinder 156 in order to start movement ofthe piston 152 from left to right and corresponding counterclockwise movement of the throttling valve 191.

Now, of course, as the restrictor b is moved closer to the orifice a, the pressure in the cylinder 156 is correspondingly increased, and this pressure will cause the spring 174 to be compressed. Through the medium of the pneumatic relay 232, the pressure on spring 223 on the cylinder 220 is also correspondingly increased. It should be noted that the pressure of the spring 174 is so calibrated that movement ofthe rod 165 and the piston 162 in cylinder 156 is directly proportional to the amount of pressure in the cylinder 156. This is also true with respect to the piston 221 and spring 223 in the cylinder 220 of the variable-speed mechanism 155. Since the maximum amount of pressure available to the cylinders 156 (Figure 7) and 220 (Figures 13 and 16) is fifteen pounds per square inch, for example, the

springs

174, 223 in the

respective cylinders

156, 220 should be so calibrated or designed that a maximum of fifteen pounds per square inch is required in order to fully compress the same.

It is thus seen that I have provided a simple and effective means to maintain a predetermined length of yarn between a yarn feeding means and a yarn take-up means and wherein the amount of yarn or length of yarn between said feeding means and said take-up means controls the speed of the feeding means or the rate at which the yarn is moved by the feeding means, although the rate at which the yarn is demanded by the take-up means may vary considerably. The yarn feeding means is driven primarily by the same means which drives the yarn takeup means as embodied in the knitting machine 12; the improved yarn length control apparatus including a variable-speed drive mechanism interposed between the knitting machine and the yarn feeding means so as to vary the rate at which the yarn is fed by the yarn feeding means relative to the means driving the knitting machine to compensate for any variations in yarn length between the yarn feeding means and the take-up means which occur due to many difierent reasons, such as inherent variable stretch characteristics in different lengths of the yarn, coils, curls or kinks in the yarn or the recurrence of relatively thin and/or thick places in the yarn, etc.

It is also seen that the yarn feeding and length control apparatus may be rendered ineffective when desired, either manually or automatically, by moving the yarn feeding gears 16, 17 apart from each other so the yarn is drawn directly from the source by the knitting instrumentalities or other take-up means. It should be noted that the cylinder 143 which controls the position of the gear 17 relative to gear 16 (Figures 9, l1, 12, and 16) may be of the double-acting type or the rod 140 may be spring-urged to active position and moved to inactive position by air pressure in a manner opposite from that heretofore described, without departing from the spirit of the invention.

It is apparent that the tension in the length of yarn forming the loop at the improved yarn length control apparatus may be maintained only slightly above that of the pull of gravity by forming the body 185 of the sensing lever 23 from an extremely light material or by counterbalancing the sensing lever 23. The tension may also be increased to any desired extent by forming the body 185 of the sensing lever 23 from a relatively heavy material or by attaching suitable weights to the same. Such weights may be in the form of adhesive tape 14 wrapped around the body of the sensing lever 23 or practically any means which may be available may be attached to the body 185 or the extension 182 of the sensing lever 23 to increase the weight thereof.

In the drawings and specification there has been set forth a preferred embodiment of the invention and, although specific terms areemployed, they are used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention being defined in the claims.

I claim: I

1..Apparatus for feeding yarn to a variable speed take-up means comprising a rotatable element in engagement with which said yarn is moved and from which said yarn extends to said take-up means, a sensing element resting upon the yarn at a point between said rotatable element and said means, means responsive to variations in the position of .the sensing element, caused by variations in the effective length of the portion of the yarn extending between the rotatable element and said take-up means, for driving the rotatable element at a speed corresponding to the speed at which the yarn is taken up While maintaining a predetermined length of yarn between the rotatable element and the take-up means, said responsive means comprising a variable-speed drive coupled to said rotatable element and including a pair of pulleys, a belt connecting said pulleys, means responsive to variations in the tension in said belt for varying the output speed of said drive, a belt tensioning device engageable with said belt, a piston rod connected to said device, a piston, a cylinder surrounding said piston, resilient means normally urging said piston in one direction, means for introducing compressed air into and releasing compressed air from said cylinder, and means responsive to movement of the sensing element in either direction from a medial position to any of a plurality of other positions for proportionately varying the amount of compressed air in the cylinder to correspondingly vary the position of the tensioning device and the speed of the rotatable element.

2. In a structure according to claim 1, said means for varying the amount of compressed air in said cylinder comprising a relay having a pilot chamber and a main air chamber therein, a normally closed main valve interposed between a source of compressed air and said main air chamber, communicative means extending from said main air chamber to said cylinder, means also maintaining communication between said source of compressed air and said pilot chamber, a throttling valve interposed in the last-mentioned means, means responsive to variations in the position of said sensing element for opening and closing said throttling valve with respect to the atmosphere, means responsive to a relative increase of air pressure in said pilot chamber as a result of the throttling valve being closed for opening said main valve whereby the main air chamber receives compressed air and transmits the same to said cylinder, means respon sive to a reduction in air pressure in said pilot chamber as a result of at least partially opening said throttling valve for closing said main valve to correspondingly maintain constant pressure in said main air chamber and the cylinder, and means responsive to further reduction in the pressure in said pilot chamber resulting from further opening of said throttling valve to exhaust compressed air from the main air chamber and the cylinder.

3. A structure according to claim 2 having a metering valve positioned in said means for maintaining communication between the source and the pilot chamber.

4. A structure according to claim 2 having a primary controller comprising a second cylinder, a second piston mounted in said cylinder, a second piston rod connected to the second piston and extending out of one end of said second cylinder, a bell crank pivotally supported adjacent the free end of said second piston rod, said second piston rod being connected to one arm of said bell 15 crank, said throttling valve being mounted in the other arm of said bell crank and having an orifice in its lower end, said sensing element comprising a lever pivotally supported substantially at the juncture of said arms of the bell crank and having a restrictor thereon movable toward and away from said orifice with movement of said sensing'elernent, communicative means'establishing communication between the end of said second cylinder opposite from said piston rod and the throttling valve and the source of compressed air whereby movement of the restrictor on said lever toward the orifice increases the effective pressure in the second cylinder as it mcreases the effective pressure, in said pilot chamber so the throttling valve moves away from the restrictor and whereby movement of the restrictor and the sensing lever in the other direction ,away from said orifice reduces the efiective pressure in said second cylinder and the pilot chamber, and resilient means urging said piston toward the end of said second cylinder to which said last-named communicative means is connected and tending to move the throttling valve toward the restrictor.

5. Apparatus for feeding yarnto a take-up means comprising a rotatable yarn feeding element engaging said yarn and from whence the yarn extends to said takeup means, a detecting member engaging and forming a loop in said yarn at a point between said element and said take-up means, said member being movable by the yarn in accordance with variations in yarn. length, a

pneumatically controlled variable-speed device coupledto said yarn feeding element, communicative means connecting said-device. with a source of compressed air, a throttling valve interposed in said communicative means and having an air escapement orifice in its lower end,

a pivoted bell crank having first and second arms there 16 on, said valve being carried by said first arm, 'a piston rod connected to said second arm, a stationary cylinder in which said piston rod-has longitudinal movement, said detecting member comprising a lever pivotally supported substantially at the juncture of said arms of the bell crank and having a restrictor thereon movable toward and away from said orifice with movement of said detecting member to vary the pressure in said pneumatically controlled variable speed device and compensatively vary the speed of the yarn feeding element, second communicative means establishing communication between the end of said cylinder opposite from said piston rod and the throttling valve and the source of compressed air whereby movement of the restrictor on said lever toward the throttling valve increases the effective pressure in the cylinder as it increases the effective pressure in References Cited in the file of this patent UNITED STATES PATENTS 1,600,464 Foster Sept. 21, 1926 2,223,914 Karns Dec. 3, 1940 2,227,355 Lawson Dec. 31, 1940 2,318,998 Ingalls; 'May 1-1, 1-943 2,825,512 Andren Mar. 4, 1958 2,838,923

Lassiter June 17;, 1958