US2634810A

US2634810A - Rotary knife fiber cutting apparatus

Info

Publication number: US2634810A
Application number: US228335A
Authority: US
Inventors: Charles W Cox
Original assignee: American Viscose Corp
Current assignee: Akzo Nobel UK PLC
Priority date: 1951-05-25
Filing date: 1951-05-25
Publication date: 1953-04-14
Anticipated expiration: 1970-04-14

Description

ROTARY KNIFE FIBER CUTTING APPARATUS 2 sHEETssHEE'r 1 Filed May 25, 1951 INVENTOR. CHARLES W- COX A r m n.

April 14, 1953 c, w, cox 2,634,810

ROTARY KNIFE FIBER CUTTING APPARATUS Filed May 25, 1.951 2 SHEETSSHEET 2 46 3 4 V g I, {g

4 INVENTOR. CHARL E 8 W C OX AT rennin:

Patented Apr. 14, 1953 ROTARY KNIFE FIBER CUTTING APPARATUS Charles W. Cox, Springfield, Pa.,

American Viscose Corporation,

assignor to Wilmington, 7

Del., a corporation of Delaware Application May 25, 1951, Serial No. 228,335

Claims. (Cl. 164-61) This invention relates to a rotary knife fiber cutting apparatus for cutting continuous filamentary material, such as a yarn, tow, rope, or other bundles of continuous filaments, into discontinuous lengths for the production of staple fiber from rayon, Vinyon, nylon, cellulose acetate, and other synthetic filamentary material. The invention is particularly concerned with that type of fiber-cutting apparatus in which the continuous material is fed to a rotating member having a radial channel through which the material is directed outwardly and from which the material protrudes until cut by a cutting member or members which cooperate with the periphery of the rotating member;

It is well known in the art to cut freshly spun artificial filament bundles in both wet and dry condition in a continuous operation, whereby the thread bundles are passed in an axial direction through a guiding channel into a rotating disc. The thread bundle passes the periphery of the rotating disc where it is usually cut by means of stationary knives. Depending upon the speed of rotation of the disc and upon the number of cutting knives arranged around the periphery thereof, it is possible to cut the thread bundles into staples of various lengths.

In using this type of apparatus, a certain amount of twist is always associated with the filament bundle because of the rotation of the radially extending portion of the bundle about the axis of the filament bundle as it is fed into the rotating disc. The amount of twist depends upon the rapidity of feed of the bundle to the disc and the speed of rotation of the disc. Since this twisting occurs about the axis of the filament bundle, the lengths of the filaments surrounding the central filaments of the bundle are of increasing length as they occupy a greater distance from the center of the bundle, such comparative lengths being taken over a given unitary length of the bundle. Since the twist is present in the filament bundle at the position of cutting, the result is a non-uniformity in the lengths of fibers cut therefrom. In many instances non-uniform length staple fibers are undesirable and it is therefore desirable to produce staple fibers having an approximately equal length.

Another objection to undue twisting of the filament bundle is the fact that in order to reduce the twisting to a minimum, the disc speed is limited.

Further, the limits of disc speed are further reduced a t e diame e 9 y m in tow being cut is increased, since the greater the diameter of the tow, the greater the variance in staple fiber length caused by the twisting of the tow. Therefore, it has been the practice, in overcoming the undesirable twisting of the tow while still maintaining the required number of cuts per unit time for any given operation, to increase the number of cutting blades which are spaced'around the periphery of the discs. This increase of cutting blades naturally increases the complexity of the apparatus and in addition, as is usually the case in a moving apparatus of this type, the increase of blades which rub or come into contact with the periphery of the rotating disc rapidly wears out the surface of the disc as well as wearing out the blades or knives or dulling the same.

It is a primary object of the present invention to overcome the aforementioned difficulties and disadvantages and provide a cutting apparatus of the rotary disc type for cutting continuous filament material which is capable of cutting the material into staple fiber lengths at increased spinning speeds, i. e., increased speeds of feeding freshly spun tow or filamentary material to the cutting apparatus, while still maintaining the twist in the filament bundle at a minimum. I t is another object of the present invention to provide an apparatus for cutting a continuous filamentary material into staple fibers which is simple in construction and which alleviates any wearing out of the disc surface or of the knives arranged about the periphery thereof.

It is another object of the invention to provide a rotatable disc type cutter which has rotating blades mounted on a rotating member or bladesupporting structure which is capable of being rotated in the same or opposite direction as the filament bundle delivery disc.

It is another specific object of the invention to provide a rotatable disc type cutting apparatus which is capable of cutting filamentary bundles into various lengths of staple.

It is still another specific object of the present invention to provide a cutting apparatus which is equally well adapted to cut a dry filamentary bundle or tow as well as a wet filamentary bundle.

Other objects and advantages of the present invention will be apparent from the accompanying drawing and the description thereof hereinafter.

With the above recited general and specific objects in-view, and other objects which will be apparent from the following detailed description of the invention, this invention consists in certain novel features of construction, and a combination of cooperative parts as hereinafter described and claimed. In order that the same may be clearly understood, reference should be had to the accompanying drawing which illustrates practical and preferred embodiments of the invention, .and in which,

Figure 1 is a sectional side elevation view of one preferred embodiment of the invention,

Figure 2 is a plan view of the embodiment shown in Figure 1,

Figure 3 is an enlarged sectional View of an alternative way in which the rotary knives may be mounted and,

Figure 4 is a diagrammatic side elevation view of the change gear box showing a modified system of driving gears.

In general, the objects of the present invention are accomplished by passing a filament bundle or tow through a funnel-like opening in the center of a rotatable disc and passing the bundle radially outward through an opening or passage in the disc to the periphery thereof by means of centrifugal force, or by means of air, liquid, steam, or the like, when the speed of rotation is so low that the centrifugal force created thereby is insufiicient for the purposes desired. As the bundle protrudes from the periphery of the rotating disc, it is periodically cut into predetermined staple lengths by means of rotating knives which do not contact the peripheral surface of the disc but come into .close tangential proximity thereto, while at the same time being rotated in the same direction with or opposite to the disc about the periphery thereof, The rotary knives while rotating on their axes, are also rotated about the filament bundle delivery disc by reason of being mounted on .a rotating supporting member or structure which, like the filament bundle delivery disc, is driven through suitable gearing from a common driving source. The filament bundle delivery disc is driven at the lowest possible speed so as to eliminate twisting of the bundle as much as possible. The increased frequency of cutting action is accomplished by increasing the speed of rotation of the knife carrying member or disc.

Referring to Figure 1 of the drawing the apparatus comprises basically a filament bundle delivery disc 3 and a knife carrying member 4 which are mounted and driven in such a manner, as hereinafter explained, as to permit rotation of the disc and member in the same or opposite direction at any desired speed. The disc 3 and the member 4 are mounted on the upper portion of the cutter housing 5, disc 3 being mounted on, and for rotation with, the central shaft ii which is supported for rotation by the bearings 7, 8, and 9. While ball bearings are shown in the drawing it is to be understood that roller bearings or the like may be employed, if desired, taking into account the axial thrust on the several shafts.

The member 4 has a downwardly extending portion 9 which is in the form of a hollow sleeve and which is mounted for rotation and supported by the bearings 10 and I I. It is to be noted that the structure 4 is mounted as a floating body on the cutter frame or housing 5, there being 'a circular rubber gasket or shock absorber I2 in the space [3 formed by the member 4 and the cutter housing 5, which gasket is held in position by the annular supporting ring I4 fitted into the inner surface of the cutter housing 5. The gasket l2 serves as a dust seal and as a shock absorber to absorb any vibration which may be caused by the rapid rotation of the member 4.

Rigidly attached to the lower end of the downwardly extending sleeve 9 of member 4 is a bevel gear l5. Attached to the lower end of shaft 5 is a bevel gear It. The gear I6 is in mesh with a bevel gear ll which is mounted on the driving shaft H! which in turn is mounted in the cutter housing on the bearings I9 and 20. Shaft I 8 is driven by the gear 2| mounted on the end thereof which is in mesh with a gear on a drive motor (not shown) or may be in mesh, or otherwise suitably connected, to a reducing gear box in turn connected to a suitable driving means (not shown).

Also in mesh with the bevel gear I6 is a bevel gear 22 mounted on the shaft 23 of the change gear box 24. 'Tineadedly mounted on the end of shaft 23 in the gear box 24 is a gear 25 locked in place by means of the lock-nut 26. Gear 25 is in mesh with the gear 2] .threadedly mounted on shaft 23 and locked in place by means of the lock-nut 29. On the other end of shaft 28 is mounted a bevel gear '30 which is in mesh with the bevel gear 15. Thus it can be seen that the shaft 6, consequently disc 3 attached thereto, and the sleeve 9 and member 4 are both rotated or driven by means of a single motor or the like.

Mounted on the upper portion of the shaft 6 for rotation therewith and in the hollowed out portion 3! of member 4 is a helical gear '32. In mesh with the helical gear 32 is a helical gear 33 mounted on the end of the transverse shaft 34 supported by bearings 35 and '36 in the hollow member or disc l. Helical gear 33 is mounted at right angles to the helical gear '32 and the shaft 34 extends outwardly toward the periphery of the member 4. On the outer end of shaft 3 2 there is rigidly attached a rotary knife blade 31 which extends tangentially toward the peripheral surface of the disc 3 and in close promixity thereto but not in contact therewith. In the term bodiment shown in Figures 1 and 2 there are two 7 such knives mounted on the periphery of the member 4, as can be seen in Figure 2, it being understood that any convenient number of such rotary or circular knives may be employed if desired.

In the embodiment shown in Figure l the gearing is so set up as to rotate shaft 5 and sleeve 9 in the same direction, as can readily be seen from the arrows encircling the various gear-carrying shafts. In order to rotate the sleeve 5 counter to the direction of rotation of shaft 6 it is necessary to employ an idler gear in the change gear box 24 in mesh with the gears 25 and 21, the latter gears being out of contact with each other. Such an arrangement is shown in Figure 4. Referring to Figure 4 an idler gear 58 is threadedly mounted on the shaft 39 in mesh with both

gears

27 and 25. Using such a system will change the direction of rotation of shaft '28 and likewise sleeve 9 and member 4. It is to be understood that the speed of rotation of both member 4 and disc 3 will depend upon the size of the gears employed in the change gear box 24 as well as the size of the idler gear mounted on shaft 39 when the disc -3 and member 4 are being rotated in opposite directions. The choice of gear sizes, etc. will be apparent to those skilled in the art.

In order to maintain the rotating knives 31 in sharpened condition, a continuous knife blade sharpening mechanism, which rests against the blades by means of centrifugal force, is employed. Referring to Figure 1, this sharpening mechanism comprises a lever 40 ivotally mounted at 4| on the downwardly hanging portion 42 of member 4. The upper portion of lever 40 comprises a hone which rests against the rotating blade 31. Threadedly mounted on the lower portion of lever 40 is a weight or nut 43 which may be screwed upwardly or downwardly thereby varying the pressure with which the lever 40 bears against the knife blade 31. If desired, the sharpening mechanism may be controlled by a spring or hydraulic or pneumatic means. It is to be understood, of course, that while for simplicity of illustration only one such sharpening means has been shown, a like mechanism would be employed with each of the rotating blades on the periphery of the support 4,

The filament bundle or tow 44 enters the top of the apparatus through the funnel-shaped opening 45 and proceeds radially outward toward the periphery of the disc 3, through the opening or passage 46 and extends beyond the peripheral surface of disc 3, as shown at Ma prior to being severed by the rotating knife 31.

In the embodiment shown in Figure 3 the rotating knife 31 is threadedly attached to the end of shaft 41, the axi of which lies in the same plane as the axis of the opening 45. Shaft 41 is mounted in the upwardly extending hollow portion 48 of the member 4. Mounted on the shaft 41 in the hollow portion 48 is a gear 49 which is in mesh with a gear 50 mounted on the shaft 34. In this embodiment there is a perpendicular cutting action on the filament bundle and in addition the blades 31 rotate in a direction opposite to that in the embodiment shown in Figure 1.

One of the primary advantages of the present invention is the fact that a bundle of dry filaments can be cut into staple fibers at a high rate of speed and does not have to be wet in order to attain this high speed. This is facilitated by reason of the rotating cutting blades since a fixed shear or knife is not satisfactory for dry cutting. This is so because a fixed blade tends to jab or break off the staple fibers rather than cut them off smoothly as is the case when employing rotary blades. Another important feature of the present invention is the fact that high speeds of feed to the cutter are possible without increasing the speed of the filament bundle delivery disc thereby limiting to a minimum the twisting of the filament bundle which, as hereinbefore pointed out, is undesirable.

By means of the present invention cutter maintenance is greatly reduced since the cutting blades or knives are out of contact with the filament bundle delivery disc. The apparatus of the present invention is compact and permits utilization of centrifugal type cutters with increased production. Numerous other advantages of the present invention will be apparent to those skilled in the art.

It is to be understood that changes and variations may be made without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. An apparatus for cutting filamentary material into staple fibers comprising rotary means for feeding a filamentary material through a path having a portion extending radially outward from the axis of rotation thereof, a rotary supporting member mounted adjacent the feeding means on the same axis of rotation, at least one rotary cutting means mounted on the member adjacent its periphery and extending transversely into the plane of said portion of the path, means for rotating the cutting means about an axis of rotation extending transversely of the first-mentioned axis, and driving means for rotating the member.

2. An apparatus for cutting filamentary material into staple fibers as defined in claim 1 wherein the feeding means comprise a rotatable disc having a radially extending opening therein for the passage of the filamentary material therethrough.

3. An apparatus for cutting filamentary material into staple fibers as defined in claim 1 wherein the rotary cutting means is mounted in close proximity to the feeding means.

4. An apparatus for cutting filamentary material into staple fibers as described in claim 1 wherein there are driving means for rotating the feeding means and member in the same direction.

5. An apparatus for cutting filamentary material into staple fibers as defined in claim 1 wherein there are driving means for rotating the feeding means and member in opposite directions.

6. An apparatus for cutting filamentary material into staple fibers comprising a rotatable disc having a radially extending opening therein for the passage of filamentary material therethrough, a rotary supporting member mounted adjacent the disc, the axes of rotation of the disc and member being coincident, a plurality of rotary cutting means mounted on the periphery of the member in close proximity to the periphery of the disc, and extending transversely into the plane of the opening in the disc, means for rotating the cutting means, each about an axis of rotation extending transversely of the first-mentioned axis, and driving means for rotating the disc and memher.

7. An apparatus for cutting filamentary material into staple fibers as defined in claim 6 wherein there are driving means for rotatin both the disc and member in the same direction.

8. An apparatus for cutting filamentary material into staple fibers as defined in claim 6 wherein there are driving means for rotating the disc and member in opposite directions.

9. An apparatus for cutting filamentary material into staple fibers as defined in claim 6 wherein the axes of rotation of the rotary cutting means lie in the same horizontal plane as the center-line of the radially extending opening in the disc.

10. An apparatus for cutting filamentary material into staple fibers as defined in claim 6 wherein the disc is mounted on a vertical shaft and the supporting member is mounted on a hollow shaft concentric with the first shaft.

11. An apparatus as defined in claim 6 wherein the rotary cutting means are out of contact with the peripheral surface of the disc.

12. An apparatus for cutting filamentary material into staple fibers comprising a housing having a vertical shaft mounted therein, a hollow shaft mounted in the housing concentric with the first shaft, a rotatable filament delivery disc mounted on the first shaft and having a radially extending opening therein for the passage of a filament therethrough, a hollow rotatable supporting member mounted on the hol low shaft adjacent the disc, gear means on the first shaft, a plurality of generally radially extending shafts mounted in the hollow member, gear means on the radially extending shafts, said gear means being in mesh with the first mentioned gear means, rotary cutting means mounted on the other ends of the radially extending shafts adjacent the outer periphery of the hollow member, .said rotary means being mountedin close proximity to the peripheral surface of the disc and out of contact therewith, and driving means for rotating the disc and member.

.13. An apparatus as defined in claim 12 wherein there are driving means for rotating the filament bundle delivery disc and the hollow mem-- ber simultaneously in the same direction.

14. An apparatus as defined in claim 12 wherein there are driving means 'for rotating the vfilament bundle delivery disc and the hollow member simultaneously in opposite directions.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,278,662 Lodge Apr. 7, 1942 2,279,718 OMalley Apr. 14, 1942