US2748429A

US2748429A - Apparatus for forming fibrous structures

Info

Publication number: US2748429A
Application number: US286716A
Authority: US
Inventors: James D A Clark
Original assignee: AB Dick Co
Current assignee: AB Dick Co
Priority date: 1952-05-08
Filing date: 1952-05-08
Publication date: 1956-06-05
Anticipated expiration: 1973-06-05

Description

J D A. CLARK 2,748,429

APPARATUS FOR FORMING FIBROUS STRUCTURES June 5, 1956 Filed May 8, 1952 3? ooqpvovobooo INVENTOR.

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ATTORNEYS.

dcr is a shaft 11 mounting a cylindrical drum 12 having a plurality of circumferentially spaced apart scrabbler blades 13 extending radially therefrom by an amount to provide a spaced relation of about A to inch (depending on the coarseness of the elements) from the surface of the foraminous separating wall 14 forming the underside of the cylinder. The shaft is adapted to be adjustable for varying the spaced relation with the separating wall portion in accordance with the type and dimension of fibers to be distributed therefrom. The shaft and the drum with the attached scrabbler blades are adapted to be rotated by a motor 15 for transmitting rotational movement to the shaft 11 by means of a belt 16 operatively connecting a sheave 17 on the motor shaft with a sheave 18 on the end of shaft 11. For normal operation, the blades are adapted to be rotated counter-clockwise in the figures at a peripheral speed of about; 560 to 2500 feet per minute and preferably at a linear speed of about 1000 feet per minute.

The underside of the cylinder is, as previously described, formed with a removable separating wall 14 having a plurality of circumferentially extending laterally spaced slots 20 arranged in side by side relation across the cylinder and provided with shutter plates 21 for circumferential adjustment relative the slots to increase or decrease the effective lengths thereof thereby to increase or decrease the amount of fibers passing therethrough depending upon the rate of feed, the dimension of the fibers and the distribution desired across the collecting wall for use in manufacture of the final product. The shutter plates 21 constitute rigid metal members or the like of curvilinear contour corresponding to the curvature of the cylinder. They are held in position by fastening bolts 23 which extend from the cylinder through aligned slots 20 in the plate thereby to permit sliding movement of the shutter plates 21 to a desired position of adjustment in which position the shutters are secured by tightening the bolts 23. While it will be sufiicient merely if one row of slots extends across the separating wall, more than one row may be used and the slotted portions may be joined to form a continuous slot across the lower portion of the cylinder or else separated by straps as shown.

In order to feed fibrous elements in uniform distribution across the cylinder, there is provided a plurality of

feed chutes

24, 25, 26 and 27 spaced in side by side relation across the top of the cylinder and leading from a distributor head 28. The distributor head comprises a horizontally disposed annular pan 29 having upright side walls 30 and a bottom wall 31 formed with equally spaced openings 32 in the peripheral portion thereof. Each opening is in connection with one of the distributor chutes 24 to 27 inclusive leading to equally spaced apart inlets across the distributing cylinder 10. A main feed duct 33 in alignment with the center portion of the pan 29 is provided with an offset arm 34 in the lower end which terminates adjacent the pan surface in the portion in which the openings 32 are arranged. The main feed duct assembly is mounted for rapid rotational movement about a vertical axis whereby fibrous elements fed through duct 33 are distributed about the periphery of the pan for admission in substantially equal amounts into each of the feed chute openings 32. Thus substantially uniform amounts of fibers are fed into each opening and subsequently across the cylinder head for transfer to the collecting wall.

In the absence of a high velocity air stream for carrying the fibrous elements through the separating wall to the collecting wall, deposition of the fibrous elements is more in the nature of settling by gravitational and centrifugal flow after they pass through the separating wall with the result that the collecting wall may be formed of separate caul plates 35 advanced in end to end relation onto an endless belt 36 operating about

rollers

37 and 38. One of the rollers may be driven by a belt 39 or the like operatively connected to a driving motor 40 or else rotational movement may be achieved by other suitable means. As the caul plates 35 pass below the depositing cylinder 10, preferably in the direction of rotation of the scrabblers, fibrous elements are deposited thereon to form a continuous layer having a thickness depending upon the speed of the belt and the rate of fiber feed. As the belt turns about .the roller 38, the caul plates 35 having the fibers deposited thereon as a layer 41 may be advanced over an adjoining roller conveyor 42 or other conveying means for further processing the fibrous elements in the formation of a molded product. Stationary side plates may be provided adjacent to but in from the sides of the caul plates in the fiber depositing zone, as shown, to form the fibrous elements perpendicularly along the side edges of the deposited layer.

A light 'eight clean-out plate 45 may be provided in the cylinder surface. Like the separating wall plate, the plate may be fastened in position by means of thumb screws 46 and may also be provided with handles 47 to simplify its manipulation.

The slotted openings 20 in the separating wall 14 are preferably dimensioned in the circumferential direction to correspond to about one-half to equal the maximum dimension of the fibrous elements in length or width and substantially equal to or greater than the largest dimension of the fibers in the crosswise direction. The openings are preferably adjusted or dimensioned to be slightly larger because little, if any, air is present to carry the fibers through the openings, as compared to the reliance on the air streams traveling at high velocity in the aforementioned copending applications. In addition, the distribution of fibrous elements in advance as they are admitted to the depositing head and the lack of cohesion between fibers provides for the desired uniformity in transmission of the fibers through the openings located across the separating wall, particularly when an excess of fibrous elements is present to maintain the desired shower-head principle.

In this connection, it is important to maintain the rate of feed of the fibrous elements in balance with the number and the dimensions of the openings so as to keep the zone adjacent the separating wall covered with a transient layer of the elements. In the event the feed of the elements becomes too great the cylinder will become clogged. On the other hand, if the feed becomes insufficient an adequate layer of transient fibers cannot be maintained and the fibers will, as a result, issue in non-uniform distribution through the openings.

With tapered end fibers dimensioned to be about /2 inch in length and about 1 inch in width prepared in accordance with the copending application Serial No. 192,- 284, filed October 26, 1950, a single row of openings 20 spaced 2 inches apart across the bottom of the cylinder and dimensioned to be 1 /2 inches square with the shutters closed down to cover about /2 inch in the direction of travel of the scrabbler blades 13, is sufiicient to produce a felted layer of such fibrous elements at the rate of 5 pounds per minute per foot of width. With crosscut fibers of lesser thickness as disclosed in my copending application Ser. No. 9,482, filed May 3, 1949, openings of about inch in diameter and spaced about 1%. inches apart and arranged in two rows spaced closely about the periphery of the cylinder have been found to felt fibrous elements on the collecting wall at the rate of about 4 pounds per foot of width per minute. With dry Asplund fibers, made by grinding wet chips of wood between blades at elevated temperatures and pressures, a plurality of rows formed with slots preferably dimensioned to /8 by 1 /2 inches may be used to give a satisfactory rate of feed.

The normal setting of the scrabbler blades 13, as previously pointed out, is adapted to range from to /2 inch from the surface of the blade and for this purpose the bearings for the shaft 11 are preferably made adjustable vertically to secure the optimum spaced relation.

Various binder compositions such as dry binder or resinous binder in aqueous emulsion or in solution may be sprayed or otherwise applied onto the surfaces of the fibers incident to their deposition on the caul plates or such dry binders in powder form may be introduced with the fibers to the depositing cylinder for applying the desired amount of binder onto the fiber surfaces prior to or subsequent to its passage through the separating wall. In the absence of a high velocity air stream, it will be apparent that one layer of fibers from one depositing head may supply the surface for receiving additional layers of fibers of similar type or of difierent types from subsequent depositing heads of the type described and that each layer may be individually treated as by a roughening agent or with a coating composition or with an interlayer composition for producing a specific fibrous structure as defined in my copending application Serial No. 110,212.

It will be obvious that in place of a plurality of feed pipes to the cylinder, as shown in Figures 1 and 2, these may be replaced by a single pipe receiving a constant supply of fibrous elements at its upper end, which is pivoted and which is oscillated uniformly back and forth across an opening in the top of and the width of the cylinder, so as to deliver the elements fairly uniformly across its width. However, because of the pause and return of the lower end of the swinging pipes at the ends of the stroke, such a uniform distribution is not achieved as with the device shown in the figures.

It will be understood that various other changes may be made in the details of construction, arrangement and operation without departing from the spirit of the invention, especially as defined in the following claims.

I claim:

1. Apparatus for preparing structures of fibrous elements of substantial dimension comprising an elongate cyl-. inder having a separating wall in the underside thereof formed with a plurality of openings arranged in spaced apart relation across the separating wall, a collecting wall spaced below the separating wall, means for feeding fibrous elements in uniform distribution into the cylinder across the length thereof in amounts exceeding that capable of passing immediately through the openings but insufficient to fill any portion of the cylinder, means for imparting rotational movement to all of the fibers contained therein constantly to move the excess as a layer across the for aminous surface of the separating wall.

2. Apparatus as claimed in claim 1 in which the means for feeding the fibrous elements in uniform distribution across the cylinder comprises feed openings spaced uniformly across the top of the cylinder, a distributor pan having openings therein corresponding in number with the feed openings in the cylinder and spaced equidistantly 'in the peripheral portion of the pan, a feed chute mounted for rotational movement over said pan having an outlet adapted to rotate in uniform communication with each of said openings, ducts communicating each of the openings in the pan with feed openings in the cylinder, and means for feeding fibrous elements at predetermined rate into said feed chute.

3. Apparatus as claimed in claim 1 in which means are provided to permit adjustment of the size of the openings in the underside of the cylinder.

4. Apparatus as claimed in claim 1 which includes a clean-out plate forming a portion of the cylinder adjacent the separating wall, and means for securing the cleanout plate in position of use.

5. Apparatus for preparing structures of fibrous elements of substantial dimension comprising an elongated curvilinear housing having a separating wall in the underside thereof with openings arranged in spaced apart relation across the separating wall dimensioned to enable fibrous elements to pass through, a collecting wall spaced below the separating wall upon which the fibrous elements which pass through the separating wall are deposited for formation of the fibrous structure, means for feeding fibrous elements in uniform distribution across the housing in amounts sutficient to maintain an excess of that capable of immediately passing through the openings of the separating wall but substantially less than that required to fill any portion of the housing, a scrabbler mounted for rotational movement in the curvilinear housing having blades which rotate with the ends just out of contact with the surface of the separating wall to cause all of the fibrous elements within the housing to rotate rapidly about the housing and constantly to move the fibrous elements as a layer across the surface of the separating wall.

6. Apparatus as claimed in claim 5 in which means are provided for adjusting the scrabbler to maintain a spaced relation ranging from hi to /2 inch between the edges of the blade-s and the surface of the separating wall during operation.

7. Apparatus as claimed in claim 5 in which the scrabbler comprises a cylinder and means for rotating the cylinder to provide a linear speed of about 500 to 25 00 feet per minute.

References Cited in the file of this patent UNITED STATES PATENTS 2,028,388 Gerard et a1. Jan. 21, 1936 2,318,064 Delaney May 4, 1943 2,350,107 Gandrud May 30, 1944 2,510,231 Juzwiak June 6, 1950 2,579,770 Uschmann Dec. 25, 1951 2,583,618 Weyerhaeuser Jan. 29, 1952 2,618,813 Patton et a1. Nov. 25, 1952