US3052928A - Method and apparatus for producing unwoven fabrics - Google Patents

Description

p 1962 R. E. CHARLTON, JR, ETAL 3,052,928

METHOD AND APPARATUS FOR PRODUCING UNWOVEN FABRICS Filed Feb. 1, 1957 5 Sheets-Sheet l GEORGE MANNING VERNA L.PAYN E ATTORNEYS Sept. 11, 1962 R. E. CHARLTON, JR, ETAL 3,052,928

METHOD AND APPARATUS FOR PRODUCING UNWOVEN FABRICS Filed Feb. 1, 1957 5 Sheets-Sheet 2 INVENTORS RICHARD E.CHARLTON,JR.

GEORGE MANNING VERNA L. PAYNE ATTORNEYS Sept. 11, 1962 R. E. CHARLTON, JR, ETAL 3,052,928

METHOD AND APPARATUS FOR PRODUCING UNWOVEN FABRICS Filed Feb. 1, 1957 5 Sheets-Sheet 3 FIG 3 36' INVENTORS RICHARD E. CHARLTON,JR. GEORGE MANNING VERNA L.PAYNE ATTORNEYS P 1962 R. E. CHARLTON, JR, ETAL 3,052,928

METHOD AND APPARATUS FOR PRODUCING UNWOVEN FABRICS 5 Sheets-Sheet 4 Filed Feb. 1, 1957 FIG. 7.

INVENTORS RICHARD E.CH-'ARLTO GEORGE MANNING VERNA L. P-AYNE BY 1M4), QM W P 1962 R. E. CHARLTON, JR, ETAL 3,052,928

METHOD AND APPARATUS FOR PRODUCING UNWOVEN FABRICS 5 Sheets-Sheet 5 Filed Feb. 1, 1957 TNVENTORS RLTON,JR. m 6 BY VERNA L. PAYNE 2424M, pug/ 24 ATTORNEYS RICHARD E C GEORGE MAN United States This invention relates to the production of unwoven fabrics and more particularly to an improved method and apparatus for producing unwoven fabrics of uniform texture and strength in all directions composed of fibers in random relationship.

The present invention contemplates improvements in the procedure and apparatus for producing unwoven fabrics disclosed in United States Patent No. 2,648,876, issued August 18, 1953, to Phillips et al. In brief, the method disclosed in this patent embodies the steps of attenuating a body of fibers so as to provide a moving source of fiber supply, removing the fibers from the source of supply by means of an air stream, passing the air stream and the fibers suspended therein to a moving foraminous fiber receiving member through a confined uninterrupted path so that the fibers will be deposited thereon. The apparatus for carrying out this general procedure, as disclosed in the Phillips at al. patent, embodies a duct system provided with a fan or the like for creating a stream of air therethrough. Preferably, the fan is of the suction tube so that it is mounted downstream. The entrance of the duct system is adjacent the fiber attenuating device and is efiective to strip the fibers on the device therefrom so that they will become entrained in the air stream. From the inlet, the duct section extends to the continuous foraminous member where the Web is formed. As disclosed in the Phillips et al. application, this tunnel or duct section preferably has an increasing height as it approaches the foraminous member. On the opposite side of the foraminous member is a receiver duct section having an adjustable throat. The throat is connected through take-01f ducts to the fan. Due to the physical requirements of the apparatus, the take-off duct connecting the throat to the source of air current or fan must move the air through a right angle in a relatively short space. Moreover, the throat preferably extends entirely across the width of the foraminous member so that the duct works connecting this throat to the fan must also restrict itself in width. As disclosed in the Phillips et al. patent, a tapered duct has heretofore been utilized to accomplish the above purpose.

In theory, it Was thought that the design of this tapered duct should be such that its cross-sectional area at any point across its width is equal to the area of the throat between that position and the adjacent end of the duct, but it has been found that this was not practical in actual construction. The constructions heretofore have given rise to an uneven pressure drop across the foraminous member and, hence, a variance in the fiow thereacross. To take care of this condition, the Phillips et al. apparatus provided flexible leaf plates Within the throat which can be adjusted so as to more or less equalize the flow across the screen.

The adjustable leaf arrangement has not proven entirely satisfactory since extensive adjustment is required throughout the operation of the apparatus. That is, the distribution of the fibers, as a result of their deposit on the foraminous member, is afiected by other factors as Well, the adjustable leaf arrangement merely serving to complicate the adjustments necessary.

An additional factor which detrimentally aifected the quality of the fabric produced by the Phillips et al. ma-

atent "see chine concerns the ratio of the cross-sectional area of the throat and the cross-sectional area of the inlets adjacent the attenuating device. In the apparatus constructed in accordance with the teachings of the Phillips et al. patent, the ratio of the area of the throat to the area of the inlet is of the order of 2 /211 and 3:1, or more. With this arrangement, it is apparent that the flow of air through the inlets will be substantially greater than the flow of air through the throat. This is particularly true Where the width of the intake is less than the Width of the foraminous member upon which the web is formed. With the use of apparatus which are capable of producing unwoven fabrics greater than the Width of the attenuating device, severe problems are encountered in spreading the attenuated fibers evenly throughout the width of the foraminous member. With a 3:1 ratio existing between the area of the throat and the inlet area, equal flow through both could only be obtained by partitioning the tunnel to guide the air laterally, lengthening the tunnel so that the air would have time to slow down uniformly to corrected velocity before reaching the throat or by increasing the fan speed until the static pressure was equaled along the throat. All of these procedures have proven impractical for one reason or another.

Accordingly, the present invention contemplates the establishment of a uniform pressure drop across the entire width of the foraminous member by the air stream passing through. This is accomplished by providing a smooth, uniform-height throat which extends the entire Width of the foraminous member and has a cross-sec tional area substantially equal to the cross-sectional area of the inlets. In any event, this ratio should never be more than 2: 1. By providing a throat of uniform crosssectional area throughout its width, which is substantially equal to the inlets, the static pressure is maintained substantially equal across the entire length of the foraminous member. The flow of air within the tunnel which carries the suspended fibers is thus substantially improved and the distribution of the fibers onto the foraminous member is more uniform across the entire width. This is true even with the utilization of a foraminous member which is substantially wider than the fiber attenuating device or source of fiber supply. With the provision of a throat of the type noted above, it has also been found that the problem of providing suitable take-off ducts to connect the source of air stream or fan thereto is considerably reduced and with the present arrangement, it is possible to utilize a conventional cylindrical duct to accomplish this purpose, which duct is considerably different in construction from the ducts heretofore utilized and thought to be theoretically desirable.

Accordingly, it is an object of the present invention to provide an improved method and apparatus for producing unwoven fabrics which are of outstanding uniformity throughout the entire width thereof.

Another object of the present invention is the provision of an apparatus embodying relatively few adjustments which are simple to effect yet achieve a high degree of flexibility in the operation of the apparatus so that high grade fabrics may be produced.

A further object of the present invention is the provision of an apparatus of the type described having improved duct means through which the stream of air is confined, such duct means embodying a novel throat construction which greatly improves the flow characteristics of the air stream.

Still another object of the present invention is the provision of an apparatus of the type described having an improved fiber transfer duct section or tunnel which minimizes the tendency of eddy currents to be created in the air flow, but effectively prevents the fibers from tending V of the sealing roll of the apparatus;

to'parallel themselves across the width of foraminous member as they are deposited thereon.

Still another object of the present invention is the provisionof an apparatus of the type described embodying improved sealing means in the duct system which effectively prevents leakageof air adjacent the area where the fibers are deposited on the moving foraminous member. Still another object of the present invention is the provision of an apparatus of the type described embodying a transfer duct section which serves to transfer the flow of air from the restricted throat to the fan or source of the air stream. A still further object of the present invention is the provision of a method and apparatus of the type described including an improved procedure and means for trimming or cutting the side edges of the fabric web produced.

' These and other objects of the present invention will become apparent during the course of the following detailed description and appended claims.

The invention may best be understood with reference to the accompanying drawings wherein an illustrative embodiment is shown.

, In the drawings:

FIGURE 1 is a side elevational view of an apparatus embodying the principles of the present invention;

FIGURE 2 is a top plan view of the apparatus shown in FIGURE 1 with certain parts broken away for purpose of clearer illustration; 7

FIGURE 3 is a fragmentary Vertical sectional view illustrating theforaminous member upon which the-web is formed and the adjacent portion of the duct system which confines the air stream therethrough so as to carry the suspended fibers to the foraminous member;

7 FIGURE 4 is a fragmentary side elevational view, with certain parts broken away, illustrating the transfer duct section of the duct system;

FIGURE 5 is a fragmentary perspective view illustrating the connection between one side of the fiber transfer duct section or tunnel, and theadjacent portion of the foraminous member carrying frame; i

7 FIGURE 6 is an enlarged fragmentary top plan view FIGURE 7 is an enlarged fragmentary front elevational view of a portion of the frame whichcarries the foraminous member; n V

FIGURE 8 is a fragmentary vertical sectional view illustrating the web cutting means; and

. FIGURE 9 .is a fragmentary rear elevationalview of the web cutting means.

Referring now more particularly to FIGURES 1 and 2 of the drawings, there is shown an apparatus which embodies the principles of the present invention. In general, the apparatus includes a fiber attenuating and carrying instrumentality, such as card cylinder 10, which is operable to provide a moving source of supply of fibers. This moving source of fiber supply is transferred from the card cylinder to an endless foraminous member or flexible screen 12 by means of an air' stream confined within a duct system, which includes a fiber transfer duct or tunnel 14 extending outwardly from the peripheral surface of the card cylinder to a point adjacent the foraminous member 12. The duct system also includes a receiver-duct section 16 mounted on the opposite side of the foraminous member 12 from the transfer duct 14 and terminating in a throat 18. 'A cylindrical take-off 'duct 20 is connected through its width with the throat 18 and communicates also with a second cylindrical duct 22 which leads to a suitable means for creating the air stream, such as a fan or the like (not shown);

It will be understood that the unwoven fabric formed on the forminous member 12 may be subsequently processed in any desired manner. For example, the web of unwoven fabric may be conducted through a drip tank where it is impregnated with a suitable impregnant and then over a vacuum cylinder where excessive impregnant is removed and, finally, the impregnated web may be suitably dried or baked in appropriate apparatus designed to accomplish this purpose.

The fiber attenuating and carrying instrumentality is supplied from a fiber lap or similar source fed thereto by feed rollers, a conventional taker-in or other common means (not shown), the mechanism illustrated in Patent No. 2,648,876 being entirely satisfactory. The feed lap is attenuated into individual fibers by the card cylinder 1%) and the fibers are carried about the periphery thereof in a clockwise direction, as shown in FIGURE 1, in the conventional manner.

As best shown in FIGURE 1, the foraminous member 12 is mounted on a frame, generally indicated at 24, for continuous movement in an endless path. The frame includes a pair of transversely spaced horizontal base plates 26 upon which are mounted a pair of end frames 28. The end frames may be of any suitable construction, as, for example, rigidly interconnected angle irons or the like. A plurality of transversely extending cross frame members 30 are rigidly interconnected between the end frames 28 and retain the same in spaced relation. Preferably, the end frames 28 are mounted on the horizontal base plates 26 for longitudinal adjustment by any suit able means, such as an adjustment screw 32 or the like. The endless foraminous member 12 is trained about a plurality of rollers 34, 36, 38, 40 and 42 arranged on the frame 24, as shown in FIGURE 1. The rollers are mounted on shafts .4, 46, 48, 50-and 52, respectively, which have their ends journaled in bearings 54, 56, 58, and 62, respectively, suitably secured to the .end frames, as by bolts or the like. For the purpose of properly tensioning the endless foraminous member, one of the rollers, as for example roller 42, is adjustably mounted on the frame. To this end, an adjustment device 64, of any suitable construction, is mounted between each end frame 28 and the associated bearing 62 of the roller.42.

The apparatus is driven from any suitable source of power (not shown) through a reduction gear box 66. From the gear box, one take-01f shaft 68 is suitably connected in driving relation through an idler shaft 70 to drive pulley 72 of the card cylinder. A second take-off shaft 74 is drivingly engaged by suitable chains and sprockets through an idler shaft 76 between the shaft 44 of the roller 34 and the gear box 66. A chain 78 is trained about sprockets fixed to one end of the shaft 44, 46 and 50 and an idler sprocket 79. In addition, the sprocket chain 78 is also trained about a sprocket secured to shaft 80, which forms a part of the cutting means of the present invention hereinafter to be more fully described. A screen cleaning brush 82 is carried by a shaft 84 journaled in bearings 86 mounted on brackets 88 suitably secured to the end frames 28. The brush 82 is rotated by means of a sprocket wheel 90 and a chain 92 is chained thereabout and about a second sprocket 94 and carried to the auxiliary shaft 76. It will be understood that the driving arrangement disclosed is exemplary and any suitable means may be employed for this purpose. The significantrelationship is that the card cylinder is driven in timed relation with respect to the movement of the foraminous member 12.

The present invention is more particularly concerned with an improved duct system which confines the air stream arranged to carry the fibers from the attenuating instrumentality 10 to the moving foraminous member 12. The fiber transfer duct 14 is supported by any suitable means, such as the frame of the attenuating instrumentality, preferably for longitudinal adjustment with respect to the card cylinder10 so that the cross-sectional area of the inlets provided adjacent the peripheral surface of the card cylinder can be varied. As best shown in FIGURE 2, the transfer. duct 14*includes a firstsection .100, which diverges inwidthv and converges in heightsoutwardlysfrorn the card cylinder. Preferably, the section 109 is of constant cross-sectional area throughout its longitudinal extent, the relative proportion between the height and width of the section being such that the cross-sectional area in any two transverse vertical planes is substantially equal. Forming a continuation of the first section 100 is a second section 102, which is of substantially constant width and which diverges in height as it approaches the foraminous member. The duct sections d and 162 are preferably constructed of sheet metal and include a bottom wall 104 having integral side walls 186 extending upwardly therefrom. A top wall 108 of sheet metal construction is formed with channel-shaped side flanges 110 which are secured to the upper edges, respectively, of the side walls 106. The top wall 108 may be reinforced by a plurality of transversely extending longitudinally spaced inverted V-shaped sheet metal members 112 suitably secured to the upper surface thereof. The end of the upper wall 188 adjacent the card cylinder 16 is provided with a means, generally indicated at 114, for adjusting individual portions of the inlet provided thereby throughout the entire width of the card cylinder. This means may conform to the means provided in the Phillips et a1. patent and, hence, a detailed description of the same is not believed to be necessary.

The side walls 166 of the second duct section 162 have reinforcing plates 116 secured thereto and a top wall 118 formed with channel-shaped end flanges 129 is secured to the upper edges of the side walls 106 and the reinforcing plates 116. The end of the top wall 118 adjacent the section 160 includes a transversely extending channel-shaped flange 122 which fits over an upwardly extending flange 123 formed on the adjacent end of the top wall 168. The end of the top wall 118 adjacent the foraminous member is folded over, as indicated at 124, and a suitable reinforcing plate 126 of inverted V-shaped construction is secured to the upper surface of the top wall 118 and includes a turned-under portion 128 disposed in spaced relation to the portion 124. A strip of leather or the like 139 is secured between the portions 128 and 124 and extends upwardly therefrom.

Secured to the outer surface of each reinforcing plate 116 is a vertically extending member 132, each of which includes a longitudinally extending flange 134 rigidly secured to the adjacent reinforcing plate 116, an outwardly extending transverse flange 136 and a longitudinally rearwardly extending flange 138 having vertically spaced and vertically elongated slots 140 formed therein. An L- shaped plate 142, having regstering vertically spaced, horizontally elongated slots 144, is adjustably secured to each flange 138 by any suitable means, such as bolts 146 extending through the registering slots 14!) and 144. Each plate 142 includes an elongated opening 148 extending downwardly from the upper edge thereof so as to receive an end of a shaft 150 having a seal roll 152 rigidly secured thereto intermediate the spaced plates 142. A side seal member 154, which may be of leather or the like reinforced on its outer side by a metal plate, is mounted adjacent the outer surface of each reinforcing plate 116 and the inner surface of the plate 142 in abutting relation to the adjacent end of the seal roll 152. Each side seal member 154 is suitably apertured, as at 156, so as to receive the adjacent end of the shaft 150. Preferably, each aperture 156 is longitudinally elongated to afford limited longitudinal movement thereof relative to the shaft. Each side seal member 154 is resiliently urged into sealing engagement with the associated end of the roll 152 and the associated reinforcing plate 116 by a plurality of coil springs 158, each mounted within a sleeve 16% rigidly secured to and extending outwardly from the plate 142. The outer end of each sleeve is internally threaded so as to receive a spring abutting set screw 162, which may be turned within the sleeve to adjust the tension of the spring applied to the side seal member 154. In addition, the side seal member is resiliently urged into sealing engagement with the surface of the foraminous member by similar spring assemblies, generally indicated at 164, carried by the transverse flanges 136 of the vertical members 132. As best shown in FIGURES 3 and 5, the leather strip is retained in engagement with the peripheral surface of the seal roll 152 by means of a rocker bar 166.

The opposite leg of each L-shaped plate 142 is rigidly secured to the frame 24. As best shown in FIGURES 5 and 7, an angle iron 168 is suitably secured to each end frame 28 so that one flange extends longitudinally forwardly. A second angle iron section 170 has one flange rigidly secured to the longitudinal flange of each angle iron 168 and its other flange extending transversely inwardly. The third vertical angle iron 172 has the free end of one of its flanges rigidly connected with the free end of the angle iron 17%, as by welding or the like. The leg of the associated L-shaped plate 142 is rigidly secured to the transversely extending flange of the angle iron 172. Extending between and rigidly secured to the longitudinally extending flanges of the angle iron 172 is a pair of vertically spaced angle irons 174 and 176. A side angle iron section 178 is connected between the angle irons 174 and 176 adjacent each end thereof. The seal roll is resiliently urged toward the foraminous member by means of springs 180 carried within sleeves 182 extending longitudinally forwardly from the ends of the shaft 150, and rigidly carried by suitable mounting brackets 184 secured to the longitudinally extending flanges of the angle irons 168. The forward end of each sleeve 182 is internally threaded to receive set screw 186, which may be turned to adjust the tension applied by the springs to the ends of the shaft.

The seal roll is driven by means of a sprocket wheel 188 mounted on end end of the shaft 150. The sprocket wheel 188 includes an annular portion 190 suitably slotted to provide a keyway for receiving a key 192, which engages within a suitable keyway in shaft 150. A bore 194 is formed in the annular portion in communication with its keyway and a coil spring 196 is disposed within the bore for resiliently engaging the key 192. The outer end of the bore 194 is internally threaded to receive the set screw 198, which engages the opposite end of the coil spring 196 and may be turned to adjust the tension of the latter. The portion of the sprocket chain 78 extending between the shafts 44 and 46 engages the sprocket wheel 188 so as to drive the seal roll 152. Preferably, a wear plate 2% is suitably secured to the transversely extending flange of the angle iron 17!? for engaging the sprocket chain 78 so that it will be retained in engagement with the sprocket wheel 188.

The bottom wall of the transfer duct 14 is sealed with respect to the foraminous member by means of a transversely extending member 202 which is secured in depending relationship to the rear edge of the bottom memher by means of an angle iron 264 rigidly secured to the lower surface of the bottom wall and to the forward surface of the transverse member 262. Secured to the lower edge of the transverse member 262 is a leather strip 206 which may be coated with "a plastic or the like. This strip is folded upwardly so as to engage the surface of the foraminous member.

The receiver duct section 16 is also made of sheet metal and includes a forward end which is rigidly secured, as by welding or the like, to the longitudinally extending flanges of the angle irons 174, 176 and 178. Rearwardly of these angle irons, the receiver section converges, as indicated at 208. The rear end of the receiver duct section is disposed horizontally and suitable angle irons 210 or the like are rigidly secured to the outer surface thereof. The throat 18 is formed by a pair of vertically spaced angle irons 212 and 214, each of which includes a vertical flange secured to the vertical flange of the associated angle iron 210, as by bolts 216 or the like. Preferably, the vertical flange of the upper angle iron 112 includes vertically elongated slots 218 arranged to receive the bolts 216 to provide adjustability for the throat. Each of the angle cut by the cutters frame 24-and extend the opening 268 of the vacuum tube. The plates 272 have their upper ends secured to the cross member 238 and their lower ends extending downwardly adjacent the 1 irons 212 and 214 also includes a horizontalflange having an outer surface which joins with the outer surface of the associated vertical flange along a smooth curve. The cylindrical duct'20 is also made of sheet metal'or the like and includes horizontally spaced flanges 220 having angle irons 222jsecured to the outer surface thereof. These angle irons include verticalflanges secured by the bolts 216 to the associated vertical flanges of the angle irons 212, 214 and 210. a

As best shown in FIGURE 4, the cylindrical duct 20 also includes spaced flanges 224 having angle irons 226 rigidly secured thereto. The cylindrical duct 22 also includes registering spaced flanges 228 having angle irons 230 secured thereto. The angle irons 226 and 230 have their abutting flanges rigidly secured together, as by bolts or the like. As best shown in FIGURE 1, the cylindrical duct 22 is supported on the frame 24 by longitudinally extending transversely spaced frame members 232 suitably secured to the frame and carrying straps 234, which are secured around the cylindrical duct 22.

Referring now to FIGURES 8 and 9, the web trimming or cutting means of the present invention includes a pair of transversely spaced mounting brackets 236 secured to the end frames 28 at the upper rear portions thereof. A transverse frame member 238 extends between and is rigidly secured to the rear ends of the brackets 236. Extending forwardly from the frame member 238 is a pair of bearings 240 within which is journaled a shaft 242. In addition, the ends of the shaft 242 are journaled in bearings 243 mounted in the brackets 236. The shaft 80 is journaled at its ends by suitable bearings 244 mounted on the brackets 236 below bearings 243. Rigidly secured to the shaft 80 intermediate its ends is a pair of rollers 246, each of'which is keyed to the shaft 80 for longitudinal movement. Each roller 246 is retained in a desired position of longitudinal adjustment by means of a sutable setscrew or the like 247. Secured to the outer end of each roller 246 is an annular cutting element 248, each of which includes a substantially comically-shaped cutting edge 250 arranged to cooperate with a conicallyshaped annular cutting edge 252 formed on an annular cutting element 254 carried by the shaft 242. The cutting edge 252 of each cutting element 254 overlaps the cutting edge 250 of the cooperating cutting element 248, and the former is resiliently urged into this engaged position by means of a spring 256 mounted in surrounding relation to the shaft 242 between the associated cutting element 254 and a collar 258 rigidly secured thereto. Each cutting element 254 is keyed to the shaft 242 by a key 260 which permits longitudinal movement of the latter but prevents relative rotation between the cutting element and the shaft. ,In addition, each collar 25% may be secured in a longitudinally adjusted position along the shaft 242, as by a set screw 262, so that proper cooperation between the cutting elements can be obtained;

In order to guide the cut edges of the web, a roller 264 is mounted on each end of the shaft 80, as'by a suitable set screw or key, in a position adjacent the associated cutting element 248. The edges of the web .cut by the action of the cutting elements 248 and 254 pass over the rollers 264 into a vacuum tube 266, which is suitably connected by conduit (not shown) to a source of air current, such as the main fan which creates the air stream through the main duct Work of the apparatus. The vacuum tube 266 includes an upper longitudinally extending slot 268 within ,which the trimmed edges of the web pass so that this material may be collected at a central station and re-used, if desired. In order .to insure that the edges of the web 248 and 254 enter the vacuum tube 268, opposed guide plates 270 and 272 are provided. The plates 270 are mounted by any suitable means on the downwardly into a position adjacent opening in spaced relation to the lower end of the plates 270. r a The shaft 80, which carries the roller 246, is driven by the main sprocket chain 78. The shaft 242 is driven in timed relation to 'the shaft through a pair ofcooperating gears 274 and 276. As shown in FIGURE 9, the gear 276 is suitably keyed to the shaft 80, while the gear'274 is suitably keyed to the shaft 242 in a position to mesh with the gear 276. The central portion of the web passing over the roller 246 is fed to an immersion tank or the like, a portion of which is shown in FIGURE 3 and generally indicated at 278.

Operation The general operation of the present apparatus is similar to that of the apparatus disclosed in the Phillips et a1. patent. That is, the fiber laps fed to the card cylinder are attenuated during their movement on the latter so that when they reach a point adjacent the transfer duct inlets 14, the stream of air entering these inlets will strip the attenuated fibers from the periphery of the card cylinder and they will move in suspended condition along with the air stream through the confines of the transfer duct 14. The entrained fibers suspended in the air stream within the transfer duct are collected on the moving foraminous member 12. a That is, the air stream is allowed to pass through the foraminous member while the fibers are deposited thereon. The depositing of the fibers on the foraminous member builds up a web thereon of randomly disposed fibers of uniform texture and strength in all directions. The web thus formed on the foraminous member is doifed therefrom adjacent the roller 38 and then passes through the cutting meanswhere the edges are trimmed a desired amount, Subsequently, the trimmed web passes into an impregnating apparatus andthen to a drying or curing apparatus, as is disclosed in the Phillips et 211. patent.

As was stated above, the significant improvements of the present invention relate to the duct system embodied within the apparatus for creating the air stream which strips the fibers from the card cylinder and conveys the same onto the foraminous member so as to form the web thereon. The present duct system provides an arrangement whereby the cross-sectional area of the inlets, provided at the forward end of the fiber transfer duct 14, may be varied without detrimentally affecting the efiiciency of the seal between the rearward end of the trans-1 fer duct and the foraminous member. In this regard, the L-shaped plates 142 are rigidly carried by the, frame 24 which carries the forarninous member. These plates are connected to the forward end of the transfer duct by means of the bolts 146 extending through the elongated slots 144 in the plates 142 and the elongated slots formed in the vertical members 132. Thus, by loosening the bolts 146, the entire transfer duct maybe moved longitudinally, within limits, so as to adjust the posit-ion of the forward end of the transfer duct with respect to the periphery of the card cylinder. Preferably, the bottom lip of the forward end of the transfer duct 14 is set at approximately A; inch from the periphery of the card cylinder. While this'is a preferred optimum setting, it will be understood that it may be suitably varied within the limits provided. It will alsorbe roll 152 is maintained in resilient engagement with the 'web formed on the foraminous member due to the action of the springs in the sleeves 182, which are rigidly mounted on the foraminous member carrying frame 24. Openings 156 in the side seals 154 are longitudinally elongated so as to accommodate a slight amount of relative longitudinal movement therein. The leather strip 136, which engages the periphery of the seal roll 152, is maintained in engagement therewith by means of the pivoted bar 166, which is suitably weighted so that the leather strip will at all times be urged into engagement with the periphery of the roll 152. The bottom lip of the transfer duct is sealed by means of the plastic coated leather strip 206, which is carried by the transverse member 2%2 and folded upwardly with respect thereto. The rearward surface of the plastic coated leather strip 206 will thus ride on the forward surface of the foraminous member and provide an effective seal therewith. It will thus be seen that sealing means is provided on the top, bottom and sides of the rear end of the transfer duct, which automatically adjusts itself to obtain an efiective seal when the transfer duct is moved longitudinally.

As disclosed in the Phillips et al. patent, it is desirable to have an adjustable upper lip for the forward end of the transfer duct and, thus, the adjustable means shown by Phillips et al. is provided on the transfer duct of the present invention. it is desirable to have a non-adjustable bottom lip, which, as stated above, is preferably set at inch from the periphery of the card cylinder. The range of the apparatus is improved with close lip settings but production control is easier with wide settings. The upper lip setting controls the density of the fibers in the air by controlling the amount of air that enters. Thus, to heavy-up on a particular part of the web requires a close lip setting at the corresponding lip position. This lets in less air at the lip position and in an attempt to have equal pressure in the transfer duct, air that entered at some other position is moved toward the position where the air supply was decreased.

The function of the fiber transfer duct is to guide the fibers from the card cylinder to the foraminous member. The air is turbulent inside the transfer duct and Whereas the general velocity direction is straight from the card cylinder to the foraminous member, there is a large amount of variation from this. It cannot be assumed that air and fibers are completely intermixed inside the tunnel, although it is apparent that the fibers are suspended in the air stream. Thus, the desired result is not always produced by making the air go where the fibers are to go. The settings of the tunnel height at different longitudinal positions can have a great effect on the texture and range of the fiber web produced. If the effective tunnel height is reduced too much adjacent the foraminous member, the fibers will tend to parallel themselves across the width of the foraminous member. If the transfer duct height is too high, there is a tendency for eddy currents to form therein, which builds up an excess of fibers that will be released at intervals, causing an undesirable uneveness in the web produced. The transfer duct, as described above, is advantageously constructed so as to minimize the creation of eddy currents in the air stream and the tendency of the fibers to parallel themselves across the width of the forarninous member. The first section 1943 is of an optimum height, which permits a maximum flow Without danger of the creation of eddy currents.

Moreover, it will be noted that this section, as shown, is arranged to spread the fibers received at the forward end along a greater width so that a web of greater width than the card cylinder width is produced. This is accomplished by maintaining a constant cross-sectional area throughout the longitudinal extent of the first section. Thus, the height of the first duct section diminishes in proportion to the increase in the width in the direction of air flow. Of course, where a foraminous web of the same width as the Width of the card cylinder is to be produced, the first duct section will simply be of uniform cross-sectional area. The second duct section 1E2 provides an increase in the height of the duct, while the width thereof remains constant. This section is rather lb short so that the creation of eddy currents therein is reduced to a minimum. By expanding the height of the duct at the second section, the fibers are presented to the foraminous member in a much more favorable manner so that the tendency of the fibers to parallel themselves across the Width of the foraminous member is reduced to a minimum. In this regard, the sealing arrangements are highly effective and prevent the creation of auxiliary air streams as a result of leakage adjacent the discharge end of the transfer duct. The sealing arrangement also minimizes the velocity losses in the air stream.

The manner in which the air stream is created within the fiber transfer duct is a highly significant feature of the present invention and constitutes a definite improvement over the procedures heretofore followed. The construction of the throat 18 is such that a constant pressure drop throughout the width of the air stream is obtained across the foraminous member. The throat is of constant height throughout its width and provides a rounded entrance which greatly improves the flow characteristics. While the height of this throat can be varied by changing the vertical position of the angle iron 212 through the bolts 216, it has been found highly desirable to maintain the cross-sectional area of the throat substantially less than twice and, preferably, substantially equal to the cross-sectional area of the inlets provided at the upper and lower lips of the forward end of the transfer duct. An optimum setting of the throat height is /2 inch tor a 60 inch width, where the upper lip inlet is x 45 inches and the bottom lip inlet is A; X 45 inches, which gives a ratio of 1.3 to 1. By maintaining the cross-sectional area of the throat approximately equal to the cross-sectional area of the inlets, a uniform pressure drop across the entire width of the foraminous member is maintained. A proper throat setting that gives no static pressure drop across the take-off duct 20 or receiver duct 16 should have the same efiect as lengthening the receiver duct section, for the air flow through the latter depends only upon the area, resistance and pressure drop. The area is, of course, constant. If the foraminous member is clean, its resistance is constant. If the throat holds the static pressure drop constant, the only variable is the resistance ofiered by the fibers on the screen. Thus, with this arrangement, a highly desirable uniformity in the fibrous web produced can be maintained. While the present apparatus will not correct marked uneveness in the laps fed to the card cylinder, low variation laps will produce low variation Webs if the apparatus is properly set. It has been found that when the lap variation is approximately 15%, the apparatus can readily be adjusted to produce a fibrous web that has a weight variation of approximately 10%.

The receiver duct section, in combination with the adjustable throat, is of a minimum longitudinal extent which is a distinct advantage due to the minimum amount of space available. It is contemplated that the receiver section may be compaitmented so as to obtain better con trol, although this is not regarded as preferable to achieve the highly satisfactory results obtained With the present apparatus. With the use of compartments Within the receiver duct section, positive control of the air flow in each partition is obtained. Any suitable construction may be employed. For example, in the embodiment of the receiver duct section shown, the width of the same is 40 inches and nine partitions may be installed across this width, with the width of each partition extending in 3!! 4!! 4!! 6!! 6!, 6!! 4", 4!! and 3". Each partition may extend from the foraminous member rearwardly to the take-off duct and each partition may be equipped with an adjustable throat which can be varied from an opening of /2 inch maximum down to a fully closed position. Any suitable means may be provided for effecting this adjustment as, for example, hand wheels suitably connected to the exterior of the duct and to each adjustable throat member. While such an arrangement offers positive control of range, the adjustments are critical and must becarefully made and, therefore, it is preferred to utilze an unobstructed receiver duct section in conjunction with the smooth uniform height adjustable throat as disclosed in the drawings, since this arrangement affords satisfactory results 'without the necessity of continual adjustments.

Cylindrical take-off duct 20 has been found to be highly satisfactory and constitutes a simple way of con necting the source of air stream to the adjustable throat .and receiver section which heretofore have required complicated and expensive structures. Theresults achieved ,by this cylindrical take-01f duct section are highly satistactory. In general, the air volume within the duct system should beadjusted so that the card cylinder is stripped at lip settings providing inlets having a total width of around A inch to A inch and an even static pressure is maintained across the receiver section with a throat setting of between inch to /2 inch for the 45 inch card cylinder toth'e 60 inch foraminous member apparatus shown. This volume will vary from about 1350 c.f.m. up to 1750 c.f.m., depending upon the particular setting used.

It has been found that sometimes the uniformity of the web formed on the toraminous member will vary at the edges thereof. That is, there is a tendency for the libers to lighten up at the edges so that it is greatly preferred to utilize an edge trimming mechanism, such as thecutting means illustrated and described above. The present cutting means is particularly advantageous in that a positive shearing action is obtained by the use of the overlapping, cooperating conically-shaped cutting edges. The arrangement can be readily adjusted to vary cess formed by the trimming operation.

It thus will be seen that the objects of this invention have been fully and efiectively accomplished. It will be realized, however, that the foregoing specific embodiment has been shown and described only for the purpose of illustrating the principles of this invention and is sub ject to extensive change without departure from such principles. Therefore, this invention includes all modifications encompassed within the spirit and scope of the following claims.

We claim:

1. In an apparatus of the type described including fiber attenuating means to provide a moving source of fiber supply, a fiber transfer duct having an open fiberreceiving end extending across the width of the moving source of fiber supply and in communication therewith with the edges defining the width of said'duct end being spaced from the source of fiber supply to form air inlets, a foraminous fiber-receiving member at the opposite delivery end of said duct, means for moving said fiberreceiving member relative to said duct, and means for creating an air stream through said air inlets, duct, and

fiber-receiving member to remove fibers from said attenuating meansand transfer them through said duct to said fiber-receiving member to form a web thereon; the improvement comprising said air stream creating means including a receiver duct section downstream of said fiber-receiving member in alignment with the delivery end of said transfer duct, said receiver duct section having an open receiving end adjacent said fiber-receiving member of substantially corresponding shape to the shape of the discharge end of said transfer duct and a throat formed at its opposite end operable to ,efiect a constant pressure drop throughout the width of the air stream across said fiber-receiving member, said throat having a width substantially equal to the width of the receiving end of said duct section, a constant height throughout its Width, a cross-sectional area not exceeding twice the cross-sectional area of said air inlets, and a continuous smooth surface inlet throughout its width, and a cylindrical take-ofi duct having a longitudinal opening its periphery communicating with said throat throughout its width.

2. In an apparatus for forming a web of randomly laid fibers matted together in uniform relation by transferring a moving source of fiber supply provided by fiber attenuating means to a traveling foraminous member; improved duct means for directing a fiberv suspending air stream from said moving source of fiber supply through and beyond said foraminous member so as to remove fibers from said attenuating means and carry them along a confined path to said fiber-receiving member to form the web thereon, said duct means comprising a first duct section of substantially constant cross-sectional area throughout its longitudinal extent and having an open fiber-receiving end extending across the width of the moving source of fiber supply and in communicationtherewith with the edges defining the width of said duct section end being spaced from the source of fiber supply to form air inlets, a second duct section having one end -merging with the opposite end of said first duct section and an opposite open end disposed adjacent the foraminous member, said second duct section being of substantially constant width and increasing in cross-sectional area throughout its longitudinal extent toward its open end, and a third duct section having an open end of substantially corresponding shape to the shape of the open end of said second duct section and disposed in alignment therewith adjacent the opposite side of said foraminous member, said third duct section having a throat formed at its opposite end for creating a substantially constant pressure drop throughout the width of the air stream across the foraminous member, said throat having a width substantially equal to the width of the References Cited in the file of this patent UNITED STATES PATENTS 188,164 Miles et a1 Mar. 6, 1877 304,527 Jarrell Sept. 2, 1884 759,271 Grifiith May 10, 1904 1,239,432 OConnell Sept. 4, 1917 1,553,040 Gruman Sept. 8, 1925 1,663,788 Zimniewicz Mar. 27, 1928 2,165,280 Lannan July 11, 1939 2,195,158 Watts Mal. 26, 1940 2,478,148 Wilson et al Aug. 2, 1949 2,648,876 Phillips et al Aug. 18, 1953 2,682,085 Novotny et a1 June 29, 1954

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