IL31638A - Apparatus for crimping yarn - Google Patents

Description

APPARATUS FOR CRIPIN& Y£SS THIS INVENTION relates to apparatus for crimping yarn.

According to the present invention there is provided apparatus for crimping yarn comprising an elongated crimping chamber having a heated crimping and setting zone therein, feed rolls disposed to feed a yarn for crimping into one end of said chamber to be folded over and crimped against a core of previously crimped yarn in said chamber and exert pressure to advance the core of crimped yarn along said chamber to a discharge point, means extracting the crimped yarn from said core at said discharge point, a presser member disposed to press against the side of said core at a point in said chamber in advance of said discharge point, yieldable means connected to cause said presser member to exert a continuous controlled pressure on said core for retarding the advance thereof and controlling the back pressure on said core in advance of said member, and a sensing means disposed to sense the position of the discharge end of said core without the introduction of appreciable additional back pressure in the portion of said core between said presser means and said discharge point, and means responsive to said sensing means to vary the relative rates of feed and withdrawal in a sense to maintain said discharge point at a substantially constant level.

The sensing means may conveniently comprise a member which rests lightly in the core at the discharge point thereof.

The presser means may be in the form of a pivotal finger and may include a weight which is arranged to cause the pivotal finger to exert pressure against a core of previously crimped yarn present in the chamber.

In order that this invention may more readily be understood, reference will now be made by way of example to the accompanying drawing in which :- Figs. 1 and 1A when joined along the line a-a show a side elevation of a stuffer crimper embodying the invention; Figs. 2 and 2Λ when joined along the line b-b show a front elevation of the stuffer crimper; Figs. 31 4, 5 and 6 are horizontal sections taken along the lines 3-31 4-4, 5-5 and 6-6, respectively, of Fig. 1 showing the construction of the parts embodied in the crimping and cooling zones; Fig. 7 is a sectional detail showing the construction of the dye applicators; Fig. 8 is a section taken on line 8-8 of Fig. 7 ; and Fig. 9 is a detail illustrating a further embodiment of the feed roll drive mechanism.

Referring to the drawings more in detail the invention is shown as embodied in a stuffer crimper comprising a housing 11 having an elongated, vertical bore 12 therein forming a crimping chamber.

The chanber as shown in Figure 6 is rectangular in horizontal cross-section with straight front and back walls 13 and end walls 14 which are rounded so as to avoid sharp corners which might damage the crimped yarn therein. The housing 11 is enclosed within a block 15 having heating rods 16 disposed therein for maintaining a desired degree of heat in the crimping chamber and extends above the bloc*: 15. At its upper end the housing 11 carries a collar 17 in which a series of spaced vertical rods 19 are supported. The rods 19 extend around the periphery of the crimping chanber 12 with their inner surfaces tangential thereto so that the rods form an extension of the chamber. The upper ends of the rods 19 are held in a horizontal wall 20 so as to form a cooling cage for the crimped filaments as the core 21 of crimped filaments advances upwardly along the rods. Λ pair of choke members in the form of opposed rakes are disposed to maintain a predetermined back pressure on the core 21 of crimped filaments in the cooling zone. These members each comprises a set of curved fingers 23 carried on a pivotal shaft 25 which is journalled in a frarae 26. Hie fraiae 26 includes end necibers having bosses 27 depending from the fraue which are adjustably supported on rods 31 secured in the collar 17. Each shaft 25 carries a rod 3 having a weight 33 thereon which is adjustable along the rod 32 for controlling the pressure exerted by the fingers 23 against the core of crxnped filauents in the cooling cage. Hie fingers extend between the rods 19 into contact with the opposite 3ides of the core 21. The point of contact of the fingers 23 with the core 21 and the consequent length of core held conpacted in the cooling zone is controlled by adjusting the bosses 27 along their supporting rods 31 · In the embodiment shown the fingers 23 are provided with internal passages 35 consaunicating with an axial passage 36 in the shaft 2 and having discharge openings 37 at or about the point of contact with the sides of the core, A dye or other treating liquid nay be supplied to the axial passage 36 by a flexible tube 38.

Ihe dye or other treating liquid is caused to inpregnate the filaments in the cooling zone to a degree which is determined by the rates of feed of the core 21 and of the liquid and the density of the core. Additional treating liquid may be applied to the core above the compacting fingers 23 where the core is less highly conpacted and the liquid can penetrate more freely by a series of nozzles 41 held in a bracket 42 and terminating in felt pads 43, in contact with the sides of the core 21. The nozzles 4l nay be supplied with treating liquid by supply ducts 44, The crimped yarn 50 is withdrawn fron the top of the core 21 through a weighted bar tension gate 51, over a guide bar 49 to a roll 52, thence to a roll 58 mounted on a bracket 57 and to a winder, not shown, which may be of the constant speed type .

For controlling the feed of the core a feeler 60 is positioned to rest lightly on the top of the core 21 and is carried by an arm 61 which forms the control arm of a micro-switch 62 mounted on the bracket 42, A pa ir of feed rolls 70 a 71 is disposed at the lower end of the crimping chamber 12 in a position to feed the yarn thereto for crimping ,. The feed roll 70 is mounted on a shaft 72 which is journalled in a bracket 73 and carries a stepped pulley 74 driven by a belt 75 from the shaft 76 of a motor 77. Two bifurcated ams 80 actuated by a solenoid 8l are adapted to shift the belt 75 between the larger and smaller diameter steps of the pulley 7 for varying the speed of the feed rolls 70 and 71 » Hie feed roll 71 s mounted on a bracket 82 which is pivoted at 83 and is spring pressed into pressure engagement with the yarn at the bite of the rolls . A set screw 85 which may have a aicroaeter setting is held in the bracket 82 to form an adjustable stop to limit the minimum clearance between the feed rolls 71 ·. This prevents damaging the filaments by the application of excessive pressure and also prevents the feed rolls from coming into contact with consequent danger of injury to the surfaces of the feed rolls on the absence of the filament in the bite . This is particularly important where one of the feed rolls ha* a roughened surface .

The feed roll 71 raay be driven with the roll 70 by gears, not shorn. At least one of the feed rolls, for example roll 70, have a transversely ground peripheral edge . That is, the grinding wheel is reciprocAted axially of the peripheral surface of the roll as the roll is slowly rotated. This forms broken microscopic grooves ( i .e . grooves having a depth of the order of 5 to 80 micro inches) , with intervening ridges extending across the peripheral surface of the roll as indicated by lines 86 ( Figure 2A) . The grooves are so microscopic in sise that they are barely visible except by reflected light and the surface feels slightly rough to the touch. However, the fractional grip of the rolls on the yarn is increased to an extent such that a lower pressure may be maintained on the filaments as they are fed through the bite of the rolls 7 and 71 · Hence the filaments are not distorted or deforced by the feed rolls. This is of particular importence in the case of soft filaments such as preheated acrylics. It has been found that a roll having peripheral ridges and grooves of a depth of the order of 45 to 8C micro-inches is suitable for the above purposes.

The feed rolls 70 and 71 ore mounted with their axes parallel "to the long sides 13 of the crinping chamber 12. A traversing guide 90 is disposed to feed the yarn 50 to the bite of the rolls. This guide 90 is carried by a forked am 91 supported to slide on bars 92 having a cam follower 93 reciprocated by a helical groove 94 of a cam roll 95 which is driven by a train of gears 96 from the feed roll shaft 72.

The reciprocation of the guide 90 is designed to effect a uniform packing of the yarn across the entire oross-sectioral area of the crimping chamber. In certain instances, however, where a non-uniform or spaced effect is desired, the yarn guide 90 may remain stationary in a position to feed the yarn into the centre of the crimping chamber. In this case the yarn may become more highly crimped and compacted at the centre of the chamber and les3 highly crimped and compacted at the edges of the chamber so that different crimp effects are randomly distributed along the yarn.

The yarn 50 is fed around a stretch roll 97 and a guide roll 98 in a succession of loops 99 j thence over the arcuate surface 100 of a preheater 1G1 and through the traversing guide 90 to the bite of the feed rolls 70 and 71 . The stretch roll 97 is driven by a belt 102 from the driven shaft 72 and the guide roll 98 is driven with the stretch roll 97 by a train of gears 103 . The rate of rotation of the stretch roll 97 is so related to the rate of rotation of the feed rolls 70 and 71 that the yarn is stretched in the preheating zone . The amount of stretch is such that the nolaculeo of the filaments are oriented longitudinally for increasing the tensile strength of the filaments. Although this would tend to impart a harsher feel to the filaments this effect is compensated for by the softening in the preheating stage and the crimping and bulking to which the filaments are later subjected. The raicroswitch 62 is connected to control the solenoid 81 in a sense to increase or decrease the rate of feed of the filaments in accordance, with the position of the top surface of the core with respect to the feeler member 60.

In the variation of Fig. 9 a pulley 107 having a hub 108 is pinned to the shaft 72 and is driven by the belt 75. The hub 108 carries the inner race of a ball bearing 109 on which a flywheel 110 is mounted. The ball bearing 109 is packed with a material such as heavy grease which is adapted to provide a friction drag between the shaft 72 and the flywheel 110, The flywheel 110 thus rotates with the shaft 72 and, by its inertia, retards the deceleration of the 3haft 7 when the driving motor is de-energized. The friction drag of the bearing 109 reduces the shock on the shaft 72 when the drive is again energized, thereby smoothing out the cycles of operation of the shaft and of the feed rolls as the drive motor 77 is alternatively energized and de-energized by the aicroswitch 62 as the feeler 60 rises and falls.

The action is tiraed so that the feed rolls do not cone to rest during the off portions of the cycle. Either the stepped pulley or the inertia drive prevents the filaments from becoming stationary and overheating on the preheater.

While the choke rakes 23 maintain the core 21 under the predetermined back pressure in the crimping and cooling zones, the portion of the core above the points of contact of the fingers 23 is free of back pressure except for the pressure exerted b the li ht feeler member 60. Hence the cooling air can permeate more readily the less highly compacted core in this portion of the cooling zone prior to the yarn being withdrawn under tension.

Hie stepped drive pulley for the feed rolls shown in the accompanying drawings is the subject in our co-pending application No. ('1Λϋ14β ΐθβ05) .3"t The flywheel arranged for the feed roll shaft as shown in the accompanying drawings is the subject of our co-pending application No. Pe4*e-*e»fi6k 3jJ&$6 Certain features of the crimping chamber and associated More specifically our co-pending application No. fttOfe Sg—frflBriftl' ■Mei describes and claims apparatus for criraping yarn coriprising a crimping chamber having inlet and discharge ends, feed means for feeding said yarn into the inlet end of said chamber to be folded over and crimped against a core of previously crimped yarn held compacted in said chamber, a series of peripherally spaced members registering with the discharge end of said chamber and forming a continuation thereof and along which said core is, in use of the apparatus, advanced for cooling and confining means comprising sets of fingers extending between said spaced members and engaging said core on opposite aides to exert a compacting pressure thereon, and means withdrawing said yarn from said core at a point beyond said compacting fingers.

Claims (4)

WE CLAIM

1. Apparatus for crimping yarn comprising an elongated crimping chamber having a heated crinping and setting zone therein, feed rolls disposed to feed a yarn for crimping into one end of said chaaber to be folded over and crimped against a core of previously crimped yarn in said chamber and exert pressure to advance the core of crimped yarn along said chamber to a discharge point, neans extracting the crimped yarn from said core at said discharge point, a presser member disposed to press against the side of said core at a point in said chamber in advance of said discharge point, yieldable means connected to cause said presser member to exert a continuous controlled pressure on said core for retarding the advance thereof and controlling the back pressure on said core in advance of said member, and a sensing means disposed to sense the position of the discharge end of said core without the introduction of appreciable additional back pressure in the portion of said core between said presser means and said discharge point, and means responsive to said sensing means to vary the relative rates of feed and withdrawal in a sense to maintain said discharge point at a substantially constant level.

2. Apparatus for crimping yarn as set forth in claim 1 wherein said sensing means comprises a member resting lightly on said core at said discharge point.

3. Apparatus for criaping yarn as set forth in claim 1 or 2 wherein said presser means comprises a pivoted finger and a weight is provided to cause said finger to exert pressure against said core.

4. Apparatus for criaping yarn as claimed in claim 1 constructed and arranged substantially as hereinbefore described with reference to and as shown by Figures 1 to 8 of the accompanying