US3067855A - Mechanism for feeding fibrous elements - Google Patents

Description

Dec. 11, 1962 R. D. LAMBERT MECHANISM FOR FEEDING FIBROUS ELEMENTS 2 Sheets- Sheet 1 Filed 001;- 22, 1954 INVENTOR.

@Jer/Qlawzri 71 E E #MMM :Qfizweyi 3,967,855 Patented Dec. 11, 1962 3,067,855 MECHANISM FOR FEEDING FIBROUS ELEMENTS Robert D. Lambert, Sandpoint, Idaho, assignor to Changewood Corporation, Chicago, 11]., a corporation of Illinois Filed Get. 22, 1954, Ser. No. 464,100

1 Claim. (Cl. 198-76) vention in the copending application resides in a pair of wheels having scrabbler blades extending radially from the periphery thereof for turning movement in opposite directions in spaced relation over the top flight of an inclined conveyor having a quantity of fiber in excess of that capable of passing beneath the wheels so that the excess fibers are displaced rearwardly into a mound in advance of the first wheel while quantities of fiber, uniform from the volumetric standpoint, continue up the conveyor for further processing. In using a feed mechanism of the type described in which the rate of feed is based upon control by volume, it is important to embody means in which the density of the material being advanced to the metering device remains substantially uniform, otherwise the weight of fiber being advanced will vary in proportion to density. To achieve these conditions, it is necessary that the lower stratum of the fibers in the mound be somewhat insensitive to the variation in height of the mound and, when used in combination with vacuum, to minimize the effect of the height of the mound. It is important further to provide for substantially uniform or constant orientation of the fibers and thus substantially uniform air permeability of the fibrous mass so that the applied vacuum will have substantially identical effect in compressing the strata.

Especially when used for the metering of heavy fibrous elements of relatively large dimension, such as are described in the copending applications Ser. No. 78,692, filed February 28, 1949, now Patent No. 2,655,189, issued October 13, 1953, and Ser. No. 344,089, filed March 23, 1953, now iatent No. 2,773,789, and the like, for feeding in the manufacture of molded boards and panels, the bulk density of the mass is high so that the height of the mound in advance of a metering Wheel has marked effect on the density of the lower stratum with the result that the weight of fibrous elements advanced varies to an appreciable degree with the height of the mound. The use of suction operating through the foraminous belt from the underside offers little relief in the control of density, and, in fact, tends to interfere with the maintenance of uniform density since the permeability of the mound to the flow of air is dependent somewhat upon the orientation of the fibers and the manner in which the suction takes on the mound.

With relatively long fine fluffy fibers, such as cotton and synthetic staple fibers, which are easily compressive in mass, it is difficult to control the uniformity of discharge from the supply source and it has therefore been difficult to maintain the height of the mound within sufficiently narrow limits so as to avoid fluctuations in the density of the fiber mass and in the resulting feed rate of the metering device of the type described. When the mound is large, its Weight serves to compress the bottom stratum passing beneath the wheel to a considerably greater extent than when the mound is small. Since the rate of feed is equal to the product of the cross sectional area of the material passing beneath the metering wheel, the speed of the conveyor and the average density of the mass of material, variations in the density of any stratum is immediately reflected by corresponding variation in the rate of feed.

The objective in control for feeding fibrous elements at a uniform rate by volumetric control has been achieved in accordance with the practice of this invention by control of conditions to maintain substantially the same height of the mound in advance of the wheel by which volume is controlled and to provide means for securing the same type and degree of orientation in the fibers in the mound. Both of these conditions existing concurrently in the mound of fibrous elements heading into the metering wheel can be made available by constant replacement of fibrous elements forming the base of the mound by constant advancement and replacement thereof with a fresh supply from an external source from which the fibrous elements are received in a fairly constant stream in haphazard arrangement so that the elements received will have practically the same amount of orientation when deposited on the conveyor, while the height of the mound is readily controllable by construction.

An object of this invention is to provide an improved method and means for feeding fibrous materials quantitatively by weight from bulk storage at a constant, predetermined rate, without appreciable short time fluctuations and it is a related object to provide means for feeding such fibers from storage without large fluctuations in the feed rate to a volumetric metering device in substantially uniform quantities and with a relatively constant degree of fiber orientation to minimize variations in the height of the mound ahead of the metering device and thereby secure a more accurate and uniform performance of the metering elements.

Another object is to provide an improved method and means for adjusting and controlling the feeding of dis crete particles of fibrous material to enable a constant rate of feed for advancement and processing into fibrous structures.

Another obiect is to provide a combined storage and feed mechanism for fibrous materials for metering the fibers at a predetermined rate for further processing.

Other objects and advantages of this invention will hereinafter appear and for purposes of illustration, but not of limitation, an embodiment of the invention is shown in the accompanying drawing in which FIGURE 1 is a schematic view in sectional elevation of a feed system embodying features of this invention;

FIGURE 2 is a sectional elevational view of a portion of the device shown in FZGURE 1 illustrating the arrangement of parts in the metering section in greater detail;

FIGURE 3 is a sectional elevational view corresponding to that of FIGURE 2 showing a modification in a metering device embodying features of this invention;

FIGURE 4 is a top plan view of the structure shown in FiGURE 3, and

FIGURE 5 is a schematic elevational view showing a still further modification.

As shown in the drawing, the feed mechanism embodying features of this invention comprises a primary feed section wherein fibrous elements are stored and which embodies means for advancing compressive fibrous materials at a relatively uniform controlled rate to a sec ondary feed section in the form of a metering device which operates by control of volume for advancing the fibrous elements at a uniform rate for further processing into fibrous structures. The primary feed section comprises a housing 10 having an inlet 11 at one end through which fibers are introduced without regard as to control for quantity or rate but it is preferred to maintain the volume of fibers in the housing or bin substantially to fill the housing or at least a part thereof.

The bottom wall of the housing upon which the compressive material rests constitutes a conveyor in the form of an endless belt 12 movable in one direction over a rigid flooring 13 for support and which is actuated for movement in the one direction by means of a driving motor 14 connected by belts 15 and 16 to driving sprockets 17 with a gear box 18 in between for speed control. It is preferred to incline the side walls 19 of the housing outwardly and downwardly so as to provide for increasing cross sectional area toward the bottom wall to minimize the likelihood of interference with the natural flow of fibers by gravitational force to rest upon the conveyor 12 forming the bottom wall.

The wall defining the other end of the housing towards which the conveyor advances comprises a vertical conveyor 20 in the form of an endless bucket and/or rake type elevator 21, which operates about an idler sprocket 22 located in a boot below the level of the floor 13 and just beyond the end of the conveyor 12 and another driving sprocket 24 which is operatively connected by a belt or chain 25 to a driving motor 26. The flight of the buckets and/or rakes 27 may be deflected inwardly beyond the upper sprocket as by means of an idler 28 to give substantially complete delivery of fibrous elements carried by the conveyor parts or if desired, in place of idler 28 or in addition thereto, brushing means, such as a rotary rake or brush wheel 29 may be employed to insure such delivery, as illustrated in FIGURE 5 of the drawing.

In position to receive the elements discharged from the buckets and/or rakes may be a collector chute 31 for conveying the fibers gravitationally upon delivery from the buckets and/or rakes to the top flight of a metering trough in the form of a horizontally disposed endless belt 32 which operates between sprockets 33 and 34, one of which is driven by means of a motor 35 interconnected by belts 36 and 37 and having a gear box 38 in between for speed control. The upper flight of the metering belt is supported upon a rigid bottom plate 39 and is confined between side walls 40 which form a continuous trough to prevent inadvertent displacement of fibers advanced in feeding relation beyond the wheel for further processing and which are contoured in advance of the metering wheel to control the height of the mound.

The metering wheel comprises a cylindrical drum 41 operatively connected to a driving motor 63 by a belt 64 for rotational movement. The wheel is mounted between journals 42 fixed to the forward ends of elongate arms 43 for rotational movement about a horizontal axis which is substantially parallel to the conveyor belt. As illustrated, the rotational movements of the wheel and the belt 32 result in opposed movement of the pins and the upper flight of the belt 32 at their point of nearest adjacency for movement. The rearward ends of the shaft supporting arms 43 are pivoted on pins 44 fixed to brackets 45 on a supporting plate 46 for rocking movement to raise or lower the drum respectively to increase or decrease the spaced relation between the upper flight of the metering belt for control of the height of the stratum of fibrous elements permitted to pass thereunder. Various means may be employed for rocking the arms 43 to vary the spaced relation between the metering wheel and the conveyor. One such means illustrated schematically in FIGURE 2 comprises a screw 47 which is threadably engaged intermediate its ends by a nut 48 pivoted on one of the arms 43. One end of the screw is provided with a turning wheel 49 while the other end is journalled in a bearing to permit free rotational movement to raise and lower the arms.

The metering wheel 41 is formed with a plurality of pins or spikes extending outwardly from the periphery of the cylinder preferably arranged in rows for operative engagement to displace material engaged thereby backwardly upon the metering belt during operation. In order to achieve greater uniformity in the volumetric ratio of fibrous elements permitted to pass forwardly beneath the metering wheel, it may be preferred to provide a suction beneath the portion of the conveyor 32 underlying the metering wheel 41. For this purpose the flooring 39 supporting the conveyor belt 32 may be formed with an opening in communication with a suction box 60 joined by a conduit 61 to suitable means for withdrawing substantially uniform volumes of air and the belt 32 made foraminous.

The side walls 40 forming the trough immediately in advance of the metering wheel are dimensioned for a height which controls the level of the mound of the fibers maintained on the belt for advancement into contacting relation with the metering wheel. Fibrous elements in excess of that capable of being retained in the mound fall over the sides into a chute 52 which leads back into the boot 23 that is swept by the buckets and/or rakes of the elevator by turning about the roller sprocket thereby to return the fibrous elements to the bin 11 for recycling.

Other elements in the feed mechanism embodying features of this invention will be described in connection Wtih the operation of the device for feeding compressive masses of materials uniformly at a predetermined rate for further processing in the manufacture of fibrous structures.

Upon operation of belt 12 of the primary feed section, the fibrous elements contained within the bin are conveyed uniformly horizontally in the direction towards the bucket or rake elevator 20. As the buckets and rakes of the elevator pass upwardly, the portion of the fibers forming the wall portion in contact with the conveyor will be continuously displaced upwardly by the buckets and/or rakes. The fibers incapable of continuing to be carried upwardly with the conveyor belts upon emergence of the pile of fibers in surface contact with the elevator will fall back onto the pile towards the rear of the bin while the remainder which is retained by the buckets and/or rakes will be conveyed by the elevator for subsequent deposition onto the metering belt 32.

For proper operating conditions wherein fibrous elements are recirculated within the bin and to fill the buckets and/or rakes uniformly with elements for conveying to the metering belt, it is desirable to maintain the amount of fibers stacked up against the belt to provide a pile which terminates prior to reaching the upper sprocket 24. For this purpose, means such as a photoelectric cell 53 or switch is provided at the desired level in the bin for operating the speed control to increase the linear speed of the conveyor 12 when the level of fibrous material falls below the switch 53 and to decrease the linear speed of the conveyor when the mound of fibers rises to a level above the switch. The feed section may be operated successfully when the level of fibers falls below the switch so long as sufficient fibers remain in contact with the end wall of the conveyor substantially completely to fill the buckets and/or rakes on the elevator. A brush wheel '70 may be positioned to remove excess fibrous material above a certain level from the rakes to insure uniformity in the amount of fiber carried for delivery when the fibers are long and fluffy.

This refinement in the control for the linear speed of the conveyor belt 12 is not essential but it is desirable since it permits variation in speed to supply sufficient material even when the bin is nearly empty to fill the flights of the elevator and to reduce the speed so as to avoid unnecessary churning of the fibrous materials contained within the bin.

Elevator conveyor 26 is adapted to be driven at a speed sufficient to elevate a quantity of fibrous material slightly in excess of that capable of continuously passing upon the flight of the conveyor beneath the metering wheel of the second feed section so that an excess of fibrous elements will be contained in the mound for constant recycling down the chute 52 for return to the bin through the boot 23. The excess material delivered by the bucket elevator is brushed back by the pins 50 of the metering cylinder 41 to form the mound 54. When this mound reaches a fixed height, the excess fibrous elements fall over the lowered sides 51 into the chute 52 to be returned to the boot 23 as previously described. The size of the mound 54 is controlled chiefiy by the height of the side walls 4 3 and the brushing action of the metering wheel 41 and is, therefore, relatively independent of the quantity of materials delivered by the elevator conveyor or the quantity of material within the bin.

Regulation of the quantity of fibrous material delivered for further processing may be made either by adjusting the height of the metering wheel by means of screw 47 or else by altering the speed of the belt 32 by means of the variable speed gear box 38.

When applying this invention to the metering of soft, fluify fine materials such as cotton and the like which are not free flowing, it is usually desirable to make belt 32 foraminous and to apply a constant degree of vacuum beneath the mound and metering wheel, as shown diagrammatically in FIGURE 3. in this figure, the belt 32 is foraminous and a suction is applied to the underside of its top run by means of suction box 29 connected to an exhaust fan (not shown) by pipe 61. In this example, the fibrous material to be metered is dropped or brushed onto a belt 32 ahead of metering or spike covered drums 62 similar in construction and direction of rotation to the metering wheel 41, but mounted obliquely across the belt. While the material is held against the belt by the suction applied to box 60, the drum 62 sweeps any excess material delivered by the elevator 21, or any excess material brushed back by the metering wheel 41, down chute 52 and back to the bin or use may be made of wheel '71 which has the pins thereon rotating in a direction opposite to the movement of the upper flight of the belt at the point of nearest adjacency of the belt and the pins to displace fibrous elements above a predetermined level into the mouth of a suction tube 72 by which the displaced fibers are returned to the bin 11. The brushing drum may be driven from the same or a separate motor 63 as used to drive wheel 41 and is driven in the same direction. If desired there may be two such drums, mounted chevron fashion as seen in FIGURE 4, so as to more easily cause the excess material in the mound 54 to be pushed over and down both chutes 52.

A number of modifications may be made to the apparatus disclosed in this invention without departing from the spirit or scope. For example, the excess material from the mound 54 may be conveyed back to the bin or elsewhere by a pneumatic tube conveyor, such as 72, which would eliminate the need for chutes 52 and the depressions 51 in the side walls. The inlet to the pneumatic conveyor would then be situated across the metering belt at the desired level of the top of the mound 54. Also the spike covered drum may be replaced by an endless belt carrying suitable rakes or spikes projecting from its surface.

By way of further modification, a second spiked drum 41 located over an extension of suction box 60, or a separate suction box, may be provided in addition to the spiked drum 41 in FIGURE 4 but spaced a short distance rearwardly thereof with a pneumatic tube such as tube 72 in communication with the upper peripheral portion thereof. By duplicating the metering means in series as described, an added degree of precision will be achievevd particularly with compressive fibrous materials, since the time interval between the two metering devices will give the web time to spring back and permit any local excess by virtue of the same section being overcompressed by the first drum or from other causes to be removed.

Having thus described the nature of this invention by which compressible fibrous materials may be metered and fed by a volumetric meter with a degree of uniformity that has not, as far as is known, been hitherto achieved, 1 claim:

Apparatus for continuously feeding compressible fibrous material at a constant and predetermined rate comprising the combination of a primary feed section and a secondary feed section, the primary feed section comprising a housing, a horizontally disposed conveyor forming the bottom wall or" the housing mounted for movement in one direction, a vertical conveyor forming the end wall of the housing in the direction towards which the bottom wall travels, means for controlling the linear speed of the conveyor forming the bottom wall of the housing to displace fibrous material against the conveyor forming the end wall in amount suflicient to meet the demands thereof, the secondary feed section comprising a trough having a horizontally disposed conveyor forming the bottom wall thereof, a drum mounted for rotational movement about an axis parallel to the conveyor belt and in spaced relation with the top surface of the conveyor thereof to define a cross-sectional area therebetween of predetermined dimension, means on the periphery of the drum for positive displacement of materials from the conveyor belt in excess of that for filling the area therebetween, means for controlling the linear speed of the conveyor forming the end wall of the housing in the primary feed section for advancing fibrous material onto the conveyor belt of the secondary feed section in advance of the drum in excess of the amount capable of passing on the conveyor beyond the drum whereby a mound of fibrous material is formed in advance of the drum which is controlled in height and contour by the height of the side walls of the trough and by gravity causing the material over and above that required for said excess to fall over the side walls of the trough, and means for returning the material so removed to the primary feed section.

References Cited in the file of this patent UNITED STATES PATENTS 146,877 Carven Jan. 27, 1874 186,804 Coons et al Jan. 30, 1877 193,319 Clanton July 24, 1877 506,960 White et a1. Oct. 17, 1893 783,821 Critchfield Feb. 28, 1905 985,392 Card et al. Feb. 28, 1911 1,564,187 Ahrens Dec. 8, 1925 2,195,018 Benoit Mar. 26, 1940 2,441,169 Roman May 11, 1948 2,635,301 Schubert et a1. 1- Apr. 21, 1953 2,641,028 Steele June 9, 1953 2,743,758 Uschmann May 1, 1956

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