US2972853A

US2972853A - False twist assembly

Info

Publication number: US2972853A
Application number: US706129A
Authority: US
Inventors: Jr Joseph F Lemieux
Original assignee: L M and L Corp
Current assignee: L M and L Corp
Priority date: 1957-12-30
Filing date: 1957-12-30
Publication date: 1961-02-28
Anticipated expiration: 1978-02-28

Description

United States Patent FALSE TWIST ASSEMBLY Joseph F. Lemieux, In, Manchester, N. assignor to L, M and L Corporation, Claremont, N.H., a corporation of New Hampshire Filed Dec. 30, 1957, Ser. No. 706,129

Claims. (Cl. 5751.6)

This invention relates to false twist devices used on spinning frames in the textile fibre industry.

False twist devices have usually included an elongated tubular body member having a pair of diametrically opposed axially extending twister pins at the upper end and yarn engaging means at the lower end. They are customarily mounted to rotate on a vertical axis in two fixed, vertically spaced bearings and a whirl or pulley is positioned on the body member, between the bearings, for rotation by a belt. The upper pairs of draft rolls are usually located along the top of the frame and the yarn engaging means of each false twist device is at a close spaced distance above the nip of a pair of lower draft rolls located along the side of the frame. A strand to be drafted passes from the nip of a pair of upper rolls angularly over a fixed rod and then down into the axial bore, or central passage, of a false twist device and thence straight downwardly into the yarn engaging means and the nip of the lower rolls. The lower rolls rotate at a greater surface speed than that of the upper rolls to attenuate, or draft the strand and the rotating pins of the twist device impart a false twist to strengthen the strand during drafting.

The object of drafting devices of the prior art has generally been to move the fibres in the strand steadily forward from the upper rollers and present the same in order to the front rollers whereby the yarn will be a thinner copy of the strand with each fibre displaced an equal amount. However, textile strands are not always uniform in cross section and there are often thick places and thin places therein.

In this invention the principal object is to not only displace the fibres in a fibrous strand an equal amount in a drafting zone but to also correct any irregularities in thickness of the strand in that zone.

Another object of the invention is to provide spring tension in a predetermined amount on a strand being drafted between two sets of draft rolls by resiliently supporting a unitary rotatable twister pin support to automatically vary the axial distance between the pins and fixed yarn engaging means.

A further object of the invention is to eliminate the fixed deflector rod over which the drafted strand is angularly bent in many spinning frames and to substitute therefor, a spring mounted, unitary, twister head and pins for creating such an angular bend, the pins rising resiliently when strand tension is temporarily reduced.

Still another object of the invention is the production of higher quality yarn from existing spinning frames by substituting a spring loaded, unitary, veltical movable,

false twist head for the usual fixed false twist tube and deflector rod thereby overcoming one of the principal causes of uneven yarn.

A still further object of the invention is to provide a simple, rugged false twist tube assembly in which both the upper and lower ends of the tube are provided with ceramic inserts for reducing wear and the entire tubular "ice wall in contact with the strand can be easily and quickl replaced.

Other objects and advantages of the invention will be apparent from the claims, the description of the drawing and from the drawing in which Fig. l is a fragmentary end view of a spinning frame showing, in section, a device according to this invention in the drafting zone.

Fig. 2 is a fragmentary view similar to Fig. 1 showing another position of the false twist head member of the invention, and

Fig. 3 is an enlarged cross sectional view of the ceramic insert at the lower end of the head member.

The drafting zone of a well known type of spinning frame used in the woolen system is shown in Fig. 1, the remainder of the frame being well known and forming no part of this invention.

A pair of upper, or feed,

draft rolls

20 and 21 are mounted along the top of the spinning frame 22, the

rolls

20 and 21 having a nip 23 and being rotated at a predetermined surface speed by mechanism not shown.

A pair of

lower draft rolls

24 and 25, having a nip 26 are mounted along the side of the frame and are rotated at a predetermined greater surface speed than

rolls

20 and 21, by mechanism not shown.

A pair of vertically spaced apart

bearings

27 and 28 are located between the upper and lower draft rolls of such frames, the bearings being fixed to the frame 22 by a suitable element 29.

In the prior art a false twist tube has been mounted to rotate on its vertical axis in bearings such as 27 and 28, without vertical movement, and a fixed deflector rod has been mounted on frame 22 along the top of the tubes around which the roping, roving or strand 31 has been angularly bent before entering each tube.

In this invention the deflector rod is completely eliminated and the strand 31 extends from the nip 23 directly into the top of the rotating false twist assembly 32 and thence in a straight line downwardly through the device and into the nip 26 of the lower rolls.

The false twist assembly 32 includes an elongated tubular body member 33 rotatable in the

bearings

27 and 28 and having a whirl 34 sleeved thereon, the whirl having a set screw 35 for afiixing the same. A flexible belt or band 36 is trained around each whirl such as 34 for rotating the same in the usual manner. The numeral 37 represents yarn engaging means of a well known type having a fixed jaw 38 and a pivoted jaw 39 the latter being oounterweighted at 40 and applying an increasing grip to strand 31 by centrifugal force during rotation of assembly 32. The

terminal tips

43 and 44 of

jaws

38 and 39 are at a close spaced distance from nip 26, this being the critical zone of drafting and this distance does not change, in this invention, in spite of the rise and fall of the twister pins.

Preferably the yarn engaging means 37 is attached to the body member 33 by threads 45 and the top 46 of the body member is of enlarged diameter to form an integral, cylindrical cap 47. Cap 47 forms an annular exterior shoulder 48 resting on bearing 27 and a hollow cylindrical recess 49 therewithin. The assembly 32 may thus be removed from the

bearings

27 and 28 by unthreading the yarn engaging means 37, loosening set screw 35 and sliding the body member 33 upwardly out of the bearings. During use, the shoulder 48 and whirl 34 prevent any vertical movement of the body member 33, thus maintaining the distance between

tips

43 and 44 and the nip 26 of

lower rolls

24 and 25. The body member 33 includes a straight axial bore 50, in continuation of recess 49 and extending down to the lower terminal end thereof.

The false twist assembly 32 includes a unitary false twist head member 53 axially slideable in the bore 50 and rotatable with the body member 33. Head member 53 preferably is provided with a cap 54 of enlarged diameter and an integral shank 55 of reduced diameter, the cap 54 slideably fitting within recess 49 and the shank 55 slideably fitting within bore 50. An annular shoulder 56 is thus provided under cap 54 which rests on the bottom of recess 49 to form a limit stop and a hollow cylindrical recess 57 is formed within cap 54- in which an annular, ceramic twister pin insert 58 is detachably alllxed as by adhesives. Pin insert 58 is preferably of porcelain and provided with a pair of diametrically opposed, axially extending

twister pins

59 and 60 as well as an axial bore 61.

The shank, or integral extension 55 of head member 53 extends from the cap 54 down to a level below the lower end of body member 33 and just above the

jaws

33 and 39 and includes a straight, cylindrical, axial bore 64 in extension of the bore 61 of insert 58. An annular groove 65 is formed in the head member 53 for a split, flexible, ring 67, the ring being detachable but serving as a stop to limit upward movement of head member 53. A key or pin 68 is located on the exterior of shank 55 and slideable in a keyway 6), formed in bore 50, to permit axial slideability of the head member 53 while assuring rotation thereof with body member 33. As shown in Fig. 1, the textile strand 31, being given a false twist, is in engagement with insert 58 at one end of assembly 32 and with yarn engaging means 37 at the other end of assembly 32. The cylindrical bore 64 of shank 55, however, does not grip the strand but merely guides and confines the strand in its path through the assembly 32.

Resilient means preferably in the form of a coil spring 70 encircling shank 55 of head member 53 is provided for continually urging the head member 53 away from the yarn engaging means 37 under predetermined spring pressure. Bore is counterbored to form a spring well 71 constituting an annular space within body member 32 for accommodating the coil spring 70. Spring 70 at one end bears against the shoulder 56 formed by the bottom face of cap 54 and at the other end bears against the annular shoulder 72 formed by the bottom of the spring well 71. If desired another coil spring, or a plurality of coil springs, may be provided in a suitable spring well to alter the characteristics of the device. It should be noted that the spring 79 is compressed only by the pressure exerted by the strand 31 so that it is responsive only to changes in tension of the strand.

In Fig. 1 the

twister pins

59 and 60 are shown rotating on the longitudinal axis of assembly 32 which axis is angularly oifset from a straight line path between

nips

23 and 26 of the two pairs of draft rolls. In full lines a strand of normal cross section is shown exerting normal uniform tension on the spring 70 whereby the pins are resiliently floating about half way between their lowermost and uppermost positions. The rim 73 of insert 58 is creating the angular bend in the strand 31 which would heretofore have been created by the fixed deflector rod of the prior art.

In dotted lines the strand 31 is shown as having an irregularity constituted by a portion of thick cross section 74, such thicker portions usually being less taut than a thinner section and thus under decreased tension. Under such conditions, the coil spring 70 raises the

twister pins

59 and 60 thereby making the angle of approach from nip 23 slightly smaller, slightly increasing the length of the path of the strand between the pairs of drafting rolls and slightly increasing the time during which the pins successively jerk the strand during their rotation. Such treatment tends to reduce the cross section of the thickened strand portion to the normal cross section and when completed the spring 70 is compressed again to its normal position.

In Fig. 2 a thin portion of strand 31 is shown, such thin portions usually being extra taut with fibres in closer frictional engagement with each other than in a strand of normal cross section. The additional tension created by the thin portion 75 tends to compress spring 70 thus lowering

pins

59 and 60. The path of the strand between nips 23 and Z6 is thus shortened to slightly relieve tension and the change of angle at rim 73 slightly reduces the bite of the pins to also reduce the time during which the rotating pins jerk the strand.

As shown in Fig. 3 because the terminal end 76 of shank 55 is constantly rising and falling relative to yarn engaging means 37, the inside diameter thereof at '77 is enlarged and a ceramic insert 78 fixed therein as by adhesive. The lower rim 79 of insert 78 is rounded and preferably both insert 78 and insert 58 are of porcelain.

It has been found that the slidability of the head member 53, and the predetermined spring load thereof away from the yarn engaging means 37, tends to reduce the breakage of strands during the spinning operation. This is probably for the reason that the spring means 70 serves as a cushion to gradually compensate for any weak portions in the strand and does not permit sharp changes in tension thereon.

I claim:

l. A false twist device for use in textile fibre spin ning machines, said device comprising a unitary false twist head member having a straight cylindrical, axial bore and diametrically opposed pins extending axially from the upper end thereof, a false twist body member having a straight cylindrical axial bore and adapted to be rotatable around its axis, said head member being axially slideable in the bore of, and rotatable with, said body member, yarn engaging means at the lower end of said body member, and spring means between said head and body members continually urging said head member axially away from said yarn engaging means but yieldable in the opposite axial direction for responding to variations in tension exerted by a textile strand on said head member.

2. A combination as specified in claim 1 wherein said false twist body member is an elongated tube having a whirl removably fixed therearound and said false twist head member is an elongated tube having an annular ceramic insert at the upper end thereof and an annular ceramic insert at the lower end thereof, said pins being integral with said upper ceramic insert.

. 3. A combination as specified in claim 1 wherein said spring means is a coil spring encircling said unitary head member and located in the axial bore of said body member, said body member includes an annular shoulder in said bore for seating one end of said spring means and said head member includes an annular shoulder for seating the opposite end of said spring.

4. A false twist assembly for use in textile fibre spinning frames, said assembly comprising an elongated tubular body member having a whirl detachably sleeved therearound and adapted to be rotated around its longitudinal axis; yarn engaging means afiixed to the lower end of said body member; an elongated unitary, tubular hea d member rotatable with said body member, said head member having an annular ceramic top with integral upstanding twister pins thereon and having a straight tubular shank extending axially through said tubular body member to a level proximate said yarn engaging means and axially slidable in said body member, said shank and body member forming an annular space therebetween, and a coil spring encircling said shank in said annular space and arranged to continually urge said head member upwardly with predetermined pressure but to yield downwardly under greater pressure exerted by a textile strand.

5. A combination as specified in claim 4 plus corresponding annular shoulders on said head and body members for limiting downward axial movement of said head member, and a split ring detachably mounted in an annular groove in said head member for limiting upward axial movement of said head member.

during upward and downward movement of saidhead member relative to said yarn engaging means.

7. A combination as specified in claim 4 plus threads on the lower end of said body member and corresponding threads on said yarnengaging means whereby said yarn engaging means is threadedly removable from said body member.

8. In a spinning frame the combination of upper and lower drafting rolls; a pair of spaced bearings fixed to said frame between said upper and lower rolls; 'a false twist assembly rotatably mounted in saidbearings for rotation around a longitudinal axis angularly olfset from a straight line between the nips of said upper and lower rolls, said assembly including a tubular body member having yarn engaging means at the lower end thereof delivering a strand into the nip of said lower rolls, a unitary, tubular head member having twister pins thereon, said head member being axially slideable in, and rotatable with, said body member, and resilient means connecting said bodyrnember to said head memher, said resilient means continually urging said head member axially away from said yarn engaging means for varying the angle of approach of. said strand to said pins and varying the length of strand between said upper and lower draft rolls in accordance with variations'in tension ofsaid strand at said pins.

9. A'combination as specified in claim 8 wherein said resilient means comprises at least one coil spring encircling, and resiliently bearing against, said head member at one end and encircled by, and resiliently bearing against, said body member at the opposite end thereof.

10. A combination as specified in claim 8 plus a whirl detachably sleeved on the exterior of said tubular body member for rotating the same; an enlarged integral top onsaid body member and on said head member proximate the pin portion thereof, and mechanism for detaching said yarn engaging means from said body member for enabling the slideable removal of said whirl from said body member.

References Cited in the file of this patent UNITED STATES PATENTS 2,846,730 .Abbott Aug. 12, 1958