US3334532A

US3334532A - Method and apparatus for cutting fiber tow into staple

Info

Publication number: US3334532A
Application number: US483368A
Authority: US
Inventors: Mylo John
Original assignee: Monsanto Co
Current assignee: Monsanto Co
Priority date: 1965-08-27
Filing date: 1965-08-27
Publication date: 1967-08-08
Anticipated expiration: 1984-08-08

Description

Aug. 8, 1967 J. MYLO 3,334,532

METHOD AND APFARATUS FOR CUTTING FIBER TOW INTO STAPLE Filed Aug. 27, 1965 20 1!?5 is. 2 l3 I 52 2 40 24 a 30 2 1 G :I i A v M l 54 Q \38 2 x I NVENTOR. JOHN MYLO ATTORNEY United States Patent 3,334,532 METHOD AND APPARATUS FOR CUTTING FIBER TOW INTO STAPLE John Mylo, Athens, Ala., assignor to Monsanto Company, St. Louis, Mo., a corporation of Delaware Filed Aug. 27, 1965, Ser. No. 483,368 4 Claims. (Cl. 83-18) This invention relates to a method and apparatus particnlarly adapted to cut staple fiber from yarns, tows, or ropes of continuous filamentary material. More particularly, the invention relates to a method and apparatus for cutting staple fibers to a uniform, selected length from yarns, tows, or ropes of continuous filamentary material which has been subjected to a crimping operation.

Natural staple fibers such as wool have an inherent curl or crimp which imparts to them certain desirable characteristics. For example, such a crimp provides resistance to longitudinal movement relative to adjacent fibers and, hence, is productive of a yarn having good tensile strength. Due to the nature of the method of spinning, however, 1nan-made fibers do not have a natural crimp and such is introduced either mechanically or by utilizing a conjugate filament. Mechanical crimping involves the passing of a heated tow of filaments between a pair of meshed gears which introduces a permanent bend therein. Conjugate filaments are those which are spun from a plurality of solutions having different characteristics. When the characteristics which diifer are in the area of shrinkage, the filament will curl or kink when heated.

Very often in the textile industry it is desirable, and in fact necessary in many instances, to blend staple fibers differing in composition such as, for example, cotton with a synthetic fiber, when making yarns and threads and the like. Staple is formed from synthetic fibers by cutting the continuous filamentary tow produced by spinning into many relatively short lengths. It is difficult, where a crimped tow is being utilized, to obtain staple having a uniform length due to the impossibility of determining to what extent the tow will draw up at various points along its length as it is crimped.

According to the present invention it has now been found that crimped staple of uniform lengths can be produced by feeding the tow across a cutting anvil positioned closely to a static generator. The static generator consists of a pair of elongated bars constructed of a relatively nonconducting material such as nylon, mounted on a rotating disc. As the tow approaches the bars it is directed into contact therewith and rubbed producing opposite static charges on the bar and the individual fibers in accordance with well known principles. Inasmuch as the fibers and the bars are oppositely charged they are attracted to one another, and in the case of the fiber, the attraction is such as to overcome the crimp and straighten it temporarily.

The fibers are held to the static generator bars while a cutting blade also mounted on the rotating disc passes across the anvil and cuts the filament into a predetermined length. As the bars continue to move with the rotation of the disc, the fibers are moved therewith a short distance before being pulled away by the combined action of centrifugal forces, a flow of air into a conduit and away from the bar, and the fact that the bar charge has become degraded by leakage onto the grounded support disc. The conduit carries the fibers to a collecting point from which they emerge as crimped staple and are baled.

It is, therefore, an object of this invention to provide a method and apparatus for producing crimped staple fibers of uniform length.

Another object of the invention is to provide apparatus for producing staple fibers of uniform length which is simple, easy to operate, and can be utilized with existing equipment.

outwardly to block the conduit 42 Patented Aug. 8, 1967.

Still another object of the invention is to provide apparatus for producing staple fibers of uniform length utilizing the action of static charges to temporarily straighten the crimped fibers while they are being cut.

Yet another object of the present invention is to provide a novel apparatus capable of producing crimped, staple fiber uniform in length in which the various fibers differ in characteristics such as denier, stretch, shrinkage, tenacity, and the like.

These and other objects and advantages of this invention will be more apparent upon reference to the following specification, appended claims and drawing wherein:

The figure is a partly section side elevation of the apparatus according to the instant invention showing the crimped tow being directed into the cutting device by feed rolls and showing the arrangement of the static generators, the anvil, the cutting blade, and the mechanism for transporting the cut fibers to a collecting device.

With continued reference to the accompanying figure,

reference 10 designates generally the cutting apparatus according to the instant invention which includes a disc 12 rotatably mounted on a shaft 14 suitably connected through a drive belt 16 to a source, such as an electric motor 18, of rotary motive power. Attached to and extending radially outwardly from the periphery of the disc 12 are a pair of elongated bars 20 constructed to a relative ly non-conductive material such as, for example, nylon, to act as static generators and, as shown, the bars 20 are each formed into a semi-circular configuration having their

opposed ends

22 and 24 terminating in spaced relation ship.

Bars 20 have a width greater than the thickness of the disc 12 so that they extend outwardly from the plane of the disc to form an open drum-shaped device having a hollow interior 26. Passageways 28 formed by the space between the ends of the bars 20 provide communication through the sides into the hollow interior of the drum for' a purpose to be hereinafter set forth.

A pair of cutting blades 30 are disposed in the passageways 28 and like the bars 20 extend outwardly from the disc 26. Radially, the cutting blades 30 extend outwardly a greater distance than do the bars 20 and are situated to pass closely over a cutting edge on the anvil 32. Thus, as the disc 12 rotates the bars 20 will pass by the cutting edge on the anvil 32 but the blade 30 will form with the anvil 32 a cutter for dividing the tow 3 4 into staple.

An enclosure 36 surrounds the disc 12 and its associated bars 20 and cutting blades 30. Entrance port 38 in which the anvil 32 is mounted is provided in the enclosure 36 as well as an exit port 40 connected to a conduit 42. A flow of air is created through the entrance port 28, the interior of the enclosure 36, the exit port 40 and the conduit 42 by a blower 44 having its inlet 46 communicating with the conduit 42 as indicated diagrammatically. Interposed between the blower 44 and the outlet 40 is a conventional condenser 48 which serves to separate the staple 50 from the flow of air.

A pair of feed rolls 52 frictionally engage the tow 34 and cause it to be fed through the entrance 38 and across the anvil 32. Motive force is applied to these rolls in an adjustable manner as by electric motors whose speed is variable. Thus, the rate at which tow 34 is fed into the cutting apparatus 10 can be adjusted for a purpose to be hereinafter described.

A conventional tow stopping means is provided and.

ment which would interfere with proper operation of the cutting apparatus is sensed by the plunger 54, it signals a solenoid (not shown) which opens a door 56 on a cutter trap 58 disposed in the conduit 42. Door 56 swings as shown in dotted lines, and directs foul staple out while the entanglement is passing through the cutting apparatus into the trap 58. After the knot or entanglement has passed as sensed by the plunger 54, the door 56, after a slight time lag, to completely clear the cutter, resumes its normal position and the operation of the cutter continues.

In operation the disc 12 and its associated static generator bars 20 and cutter blades 30 are rotated at a rapid speed while the feed rolls 52 supply a crimp tow 34 through the entrance port 38. The rapid flow of air produced by the blower 44 through the enclosure 36 causes the tow 34, after it has ridden across the anvil 32, to stand out rigidly as shown at 60. Thus, as the static generator bars 20 rotate by the anvil 32, they contact the tow as shown at 60 rubbing across it and producing, in accordance with well known principles, opposite static charges on the two.

The tow end 60 is attracted to the static generator 20 and held closely thereto as it rotates since, as is well known, oppositely charged elements are attracted to one another. This attraction causes the tow end 60 to tend to rotate with the static generator bar 20, but it is prevented from doing so inasmuch as the tow 34 is being fed through entrance port 38 at a linear speed lower than that of the bar 20, thus retarding it. Tension is therefore, produced in the tow end 60 causing the crimp therein to be temporarily removed.

As the disc 12 continues rotating knife 30 comes into a cooperating position with the anvil 32 and cuts the tow separating end 60 from it. The tow end 60 is then free to be carried with the static generator bar 20 and is transported with it as far as a pick off point 61 formed at the enclosure exit 40.

After the tow end 60 is freed from the tow 34 there is no friction between it and the static generator bar 20, and, thus, the production of static charges ceases. The static charges on the tow end 60 and the bar 20 tend to leak to the disc 12 which is grounded through slip ring 62 and ground wire 64 shown diagrammatically. This diminishes the attraction of the tow end 60 and the static generator bar 20 for one another which fact, in combination with the flow of air through the exit 40 and centrifugal force produced by rotation of the disc 12, causes the staple 50 to be separated from the bar 20 at the pick off point 61.

After being separated from the static generator bar 20 the staple 50 reassumes its crimped configuration and is transported on the stream of air produced by the blower 44 through the conduit 42 to a conventional condenser 48 where it is separated from the air. Thereafter the staple is packed into bales or otherwise further treated as desired.

The length of staple produced can be varied by adjusting the speed of the feed rolls 52 relative to the rotational speed of the disc 12. The more rapid the tow is fed into the enclosure 36 the longer the staple will be, and conversely shorter staple will be produced by slow feed roll speeds.

It will be apparent that by utilizing the teachings of this invention a cutter for the production of staple cut from crimped tow having a uniform length may be produced. The operation of the cutter is relatively foolproof and the device itself is simple and economical to manufacture. Thus, a long standing problem, i.e., the production of crimped staple having uniform lengths has been overcome.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore to be intended to be embraced therein.

I claim:

1. Apparatus for cutting crimped, filamentary material into fibers of a predetermined length comprising:

(a) a rotatably mounted supporting disc having a static generator and a cutting blade secured thereto;

(b) an anvil mounted proximate said disc so that said cutting blade and static generator will pass closely thereto;

(c) means enclosing said disc and anvil including an entrance and an exit, said entrance leading to said anvil and said exit connected to means for creating a flow of air therethrough;

(d) fiber collecting means in said flow of air between said enclosure exit and said means for creating an air flow; and

(e) means for feeding a crimped fiber into said enclosure entrance at a selected rate whereby said fiber passes across said anvil and is directed into contact with said static generator by said air flow where it obtains a static charge, temporarily removing said crimp, and is then cut to the desired length and removed from said enclosure to said collecting means by said air flow.

2. Apparatus for cutting crimped filamentary material into fibers of predetermined length comprising:

(a) a rotatably mounted, electrically grounded disc;

(b) a pair of relatively non-conductive elongated bars secured along the periphery of said disc forming with said disc an open, hollow, cylindrical drum;

(0) the ends of said elongated bars spacedly terminating one from the other, defining a pair of openings into said drum;

(d) a cutting blade mounted in each of said openings and extending radially outwardly from the periphery of said disc;

(e) an anvil mounted proximate said drum so that said cutting blade and elongated bars pass closely thereto as said drum is rotated;

(f) means enclosing said drum and anvil including an entrance leading to said anvil and an exit connected to means for creating a flow of air therethrough;

(g) fiber collecting means mounted in said air flow between said enclosure exit and said means for creating an air flow, and

(h) means for feeding a crimped fiber into said enclosure entrance at a selected rate whereby said fiber passes across said anvil and is directed into contact with said static generator by said air flow where it obtains a static charge, temporarily removing said crimp, and is then cut to the desired length and removed from said enclosure to said collecting means by said air flow.

3. Apparatus according to claim 2 wherein said bars are nylon.

4. A method for cutting crimped, filamentary material into fibers of a predetermined length comprising the steps of:

(a) feeding said fiber at a selected rate across a cutting anvil;

(b) placing a static electrical charge on said fiber past said cutting anvil;

(c) utilizing substantially said static electrical charge to temporarily remove said crimp; and

(d) cutting said fiber after a predetermined length has passed across said cutting anvil.

References Cited UNITED STATES PATENTS 4/1965 Langer 83l8 4/1965 Rosenthal 83175 X

Claims

4. A METHOD FOR CUTTING CRIMPED, FILAMENTARY MATERIAL INTO FIBERS OF A PREDETERMINED LENGTH COMPRISING THE STEPS OF: (A) FEEDING SAID FILTER AT A SELECTED RATE ACROSS A CUTTING ANVIL; (B) PLACING A STATIC ELECTRICAL CHARGE ON SAID FIBER PAST SAID CUTTING ANVIL; (C) UTILIZING SUBSTANTIALLY SAID STATIC ELECTRICAL CHARGE TO TEMPORARILY REMOVE SAID CRIMP; AND (D) CUTTING SAID FIBER AFTER A PREDETERMINED LENGTH HAS PASSED ACROSS SAID CUTTING ANVIL.