US 2217766 A
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Description (OCR text may contain errors)
Oct. 15, 1940. w. E;-NEFF 2,217,766
' STAPLE CUTTING APPARATUS Filed NOV. 24, 1959 M70507? I lNVENTOR v ATTORNEY Patented Oct. 15, 1940 UNITED I STATES STAPLE ou'r'rmo arrana'ms v I William E. Neif, Williamsville, N, 1, m to a E. L du Pont de Nemours & Company, Wilmin H ton, Del., a corporation of Delaware a l f Application November 24, 1939. Serial No. 305,349 -1c1aim.(ci.1c4'-s1)' This invention, relates to the'production of artificial staple fibers. More particularly, it ref annular chamber I! located within the funnel lates to' an improved apparatus for the produc tion of artificial fibers of uniformstaple length from bundles of continuous filaments.
The cutting of continuous filaments into fibers of staple: length'has beenaccomplished, heretofore, by feeding a bundle of filaments downwardtension to said filament bundle. As the filament bundle, so tensioned, emerges from the bottom of the funnel conduit, it is cut by means of knives mounted on a disc rotating in a horizontal plane.
1. Such previously suggested method and apparatus for the cutting of staple fibers is subject to certain objectionable disadvantages. Unless the knife blades are maintained with exceptionally keen cutting edges, all of the filaments in the bundle will not be cleanly out. Some of the filaments will merely be pushed aside. Turbulence. of the flowing'liquid, as it emerges from the funnel, causes a fluttering of the filament bundle which results in the cutting of staple fibers of non-uniform length. If the filament bundle is sheared by cooperation. of the funnel end and knife blade, a staple fiber chip is formed which must be subjected to a fiber opening operation.
It is, therefore. an object of the present invention to provide a staple fiber cutting apparatus which is not subject to the above-mentioned disadvantages.
Other objects of the invention will appear hereinafter.
The details of the invention will be more clearly apparent'by referring to the following description when taken in connection with the accompanying illustrations, in which:
Figure I is a diagrammatic side elevational view, with parts shown in section, of a staple cutting apparatus constructed in accordance with the present invention.
Figure 2 is a top plan view of a horizontally rotating disc containing a plurality of cutting knives.
Referring to the drawing, reference numeral designates a bundle of continuous filaments which may be passed to the feed roll |3 directly from a spinning operation. Alternatively, it may be passed to the feed roll from any other source. The feed roll i3 is preferably of a fluted type in order to prevent sticking of the filament bundle to the surface of the roller. The filament bundle passes downwardly into a funnel head It. The funnel time. is counecteato a conduit. i'l which is adapted to supply liquid to an head It. A conduit 2| is positioned in the bottom of the funnel head I! insuch a' manner that the liquid flowing from chamber i9 is adapted to flow from the bottom of the funnel head into conduit.2l. The flow of the liquid. through the conduit 2| will impart'a drag or tension onthe filament bundle I] which. also .passes through 1 the conduit. Conduit 2| is fastened'toa supporting plate 23. A second conduit 21 ispositioned in axial alinement with conduit 2|, but is spaced a slight distance from the bottom of conduit 2|. Conduit 21 is fastened to supporting 1 plate 23 by means of 25. A motor 29 is also positioned on supporting-plate 23. A vertical drive shaft of the motor projects through plate 23. A knife disc 3| connected to the end of the vertical drive shaft of the motor. The knife disposed knife blades 33. The knife blades 33 are preferably attached to the knife disc 3| at an angle of about 45 to a radius drawn from the center of the disc to the point of attachment of 25 the blades. The knife disc is positioned so that the knife blades 33 will pass between conduits 2| and 21 upon rotation of the knife disc 3|. The knife blades are slightly spaced from either of the two conduits so as to cut the filament o bundle with a so-called flying cut, that is, the knife blades do not have a cooperation with either of the conduits, or other element, to shear the bundle of filaments. Although the thickness of the knife blades may vary considerably, from a 35 standpoint of length of life and ease of cutting with a minimum of sharpening, it has been found that such blades having a thickness of approximately inches are particularly suitable. It has furthermore been found that the spacing between the conduits and a knife blade is of imcross-sectional diameter at least 30%, but not 50 more than 150% greater than the internal crosssectional diameter of conduit 2|. Preferably, the internal cross-sectional diameter of conduit 21 is between 50% and 100% greater than that of conduit 2|.
, 20 disc 3| is provided with a plurality of angularly The filament bundle does not feed as or out well unless the relative tube sizes are within the above-mentioned By means of the above-described apparatus, the filament bundle II is held in tensioned position as the knife disc rotates and, as a consequence, short lengths 35 are cleanly severed from the filament bundle. These lengths 35 passing through conduit 21 are thrown downwardly by force of the liquid flowing through conduit 21 on to a perforated moving belt 31. The force of the impact of the short lengths 35 causes them to separate into individual filaments on the belt 31. The mass, of filaments 39 is continuously passed between wringer rolls 4! and 43 and is matted on the belt 31 in the form of a thick spongy felt 45. The felt 45 can be dried on the belt 31 or may be passed into a water bath or other treating liquid bath and then removed to a drier or the like.
The liquid used in drawing the filaments through conduits 2| and 21 may be a coagulating and regenerating solution for the filaments, or it may be a treating solution for the filaments, such as a desulfuring or bleaching solution, or it may be water or other washing solution. Inasmuch as the various solutions which may be used would have a corrosive action on materials, it is desirable that the various elements of the staple cutter be made of a corrosion-resistant metal, or from hard rubber, resin or other corrosion-resistant material. It is particularly important that the knife blades be resistant to corrosion by any of the solutions which may be used as the tensioning liquid. Not only must the knife blades be resistant to corrosion, but they must be capable of holding a sharp edge for a considerable period of time. It is preferred that the knife blades be made of Hastelloy C. This material is particularly adapted for use as knife blades in the present invention in view of its ability to maintain a sharp cutting edge and also because of its corrosion-resistant properties. The other elements of the cutting apparatus may, if desired, also be constructed of this material. Hastelloy C has a composition as follows:
Per cent Nickel 58 Iron 6 Chromium 14 Molybdenum 17 Tungsten 5 In accordance with the present invention, it is essential that the bundle of filaments be tensloned or drawn through the conduits by means of a liquid so as to impart; sufiicient tension to the bundle of filaments that a rotating knife making a flying cut will sever the filaments to a uniform staple fiber length. It is also essential that an axially alined conduit be positioned below the rotating knife blades. The lower conduit holds the ends of the filaments in a downward position while the knife passes through them. The tendency of the-rope to swing or flutter is greatly reduced with the result that staple fibers of remarkably uniform lengths will be produced. By the use of the lower axially alined conduit, the life of the cutting edges of the knives is very greatly increased so that a cutting machine will run for seven to ten days before changing of a blade is required. Substantially no operating time will be lost by replacement of knife blades.
By the use of the present invention, staple fibers cut from the continuous filament bundle will be almost entirely opened, that is to say, there is substantially no chip formation. This is accomplished by a combined action of the tensioning solution, the lower axially alined conduit, the flying out of the knives, and the perforated conveyor belt. In the absence of a shearing cut, the filaments will not be squeezed together at the point of cutting and, therefore, the small bunch of staple fibers will be very easily opened. The liquid passing through the conduits brings the filaments into parallel alinement and drives the fibers against the conveyor belt. The ends of the cut fibers strike the belt and .the various fibers of the small bunch separate in all directions.
Since it is obvious that many changes-and modifications can be made in the above-described details without departing from the nature and spirit of the invention, it is to be understood that the invention is not to be limited to the said details except as set forth in the appended claim.
A staple fiber cutting apparatus comprising a vertical feed conduit, means for feeding a bundle of continuous filaments downwardly through said conduit, means forpasslng liquid concurrently with said bundle of filaments, through said conduit, a second conduit spaced from the bottom end of said first conduit, said conduits in axial alinement with each other, said second conduit having an internal cross-sectional area between 30% and 150% greater than that of the first conduit, a vertical knife shaft positioned adiacent said conduits, a knife blade positioned on said shaft to rotate therewith and pass between said spaced alined conduits.
WILLIAM E. NEFF.