US2747470A

US2747470A - Method and apparatus for fissuring wet felted fiber board

Info

Publication number: US2747470A
Application number: US103558A
Authority: US
Inventors: William R Jones
Original assignee: Celotex Corp
Current assignee: Celotex Corp
Priority date: 1949-07-08
Filing date: 1949-07-08
Publication date: 1956-05-29
Anticipated expiration: 1973-05-29

Description

W. R. JONES May 29, 1956 NG WET FELTED FIBER BOARD METHOD AND APPARATUS FOR FISSURI Filed July 8, 1949 2 Sheets-Sheet 1 METHOD AND APPARATUS FOR FISSURING WET FELTED FIBER BOARD Filed July 8, 1949 W. R. JONES May 29, 1956 2 Sheets-Sheet 2 a Q O o o f um w k United States Patent METHOD AND APPARATUS FOR FISSURING WET FELTED FIBER BOARD William R. Jones, Wabash, Ind., assignor to The Celotex Corporation, Chicago, 111., a corporation of Delaware Application July 8, 1949, Serial No. 103,558

6 Claims. (Cl. 92-39) The apparatus to which this invention relates is an apparatus for imparting certain desired characteristics to a board form material manufactured from fiber.

To describe the invention generally, it comprises an apparatus for screeding the surface of a felted fiber sheet as an intermediate step in the production of the finished fiberboard so as to provide, at a face of the board material, more or less irregular fissures which, on the one hand, are decorative and may be said to provide a decorative finished board. On the other hand the fissures comprise openings extending from the surface of the board into the interior thereof, to thus expose a greater portion of the interior fibers to impacted sound waves, whereby such fissuring at a surface of a board increases the ability to absorb impacted sound waves and thus provide a sound absorbing or acoustical product.

Briefly, the invention relates to a more or less conventional board forming apparatus wherein fiber is felted, as a thick sheet, from a fiber suspension, and after the water has been removed therefrom to a sufficient amount so that the sheet is consolidated, the upper surface of the sheet is screeded. In the screeding procedure the surface of the board is first irregularly cut or scored, and then the sheet proceeds under a serrated screed member which, through its frictional effect on the surface of the sheet, parts or separates the surface portion of the sheet along irregular lines, thus producing irregularly disposed fissures in the surface portion of the board, which fissures open from the surface to the interior thereof. The sheet may then pass under a smoothing roll which acts as a thickness regulating device. The sheet then is dried and may be cut into desired elements, such as tiles or the like.

The particular object of the invention is to provide an apparatus for producing a felt fiber sheet which is irregularly fissured, with fissures extending from the surface to the interior of the sheet. it is also an object of the invention to provide a simple apparatus for the purpose just referred to, and an apparatus which is readily adjustable, simple, low cost, and has other and additional advantages which will be apparent upon reading the following detailed description of the apparatus.

In the accompanying drawings,

Figure l is a schematic vertical section of the apparatus;

Figure 2 is a top plan view of the device;

Figure 3 illustrates a preferred pattern for the impression or scoring roll;

Figure 4 is a plan view of a resulting tile product;

Figure 5 is a cross-section taken on line 55 of Figure 4;

Figure 6 is an elevation of the screed shaft;

Figure 7 is a top plan view of the screed backing plate;

Figure 8 is a top plan view of the screed; and

Figure 9 is an elevation illustrating an impression or scoring element.

' In the accompanying drawings the various parts thereof are referred to throughout by the same numeral.

-The apparatus hereof comprises means for forming a felted fiber sheet from a fluid suspension of fiber.

This

ice

portion of the apparatus, that is, the portion for forming the felted sheet, is more or less conventional, and such has been illustrated only generally and more or less schematically, and it will be described only generally.

The felting device comprises a chest 10 in which there is maintained a supply of fiber suitably suspended in water and in which, in general, the fiber is in very dilute suspension. That is, the fiber content is ordinarily around 4 to 6% and not more than about 7 or 8% at the most. Located in the chest 10 there is provided a chest roll 11 around which there is trained a forming wire 12. At the other end of the chest 10, and illustrated as in a projecting prolongation thereof, there is provided a second roll 13 about which the wire 12 also passes, so that the two rolls, 11 and 13, and wire 12 trained thereover, constitute an endless conveyor. Wire 12, of course, is understood to be a relatively fine screen which, however, in the paper and board making art, is ordinarily referred to as the wire, and which herein will be generally so designated.

It will be seen that roll 11 is submerged with the fibrous suspension maintained in chest 10, and that the wire extends in a generally upwardly direction therefrom 'over

idler rolls

14 and 15, so that the run of the wire, or at least the upper run of the wire from the idler roll 14 to roll 13, is substantially horizontal. Suitable suction boxes 16 may be provided under the horizontal run of the wire, 12, as is usual in board forming art. These suction boxes 16 are connected to a source of suction, and due to the suction they remove excess water from the felted sheet on the screen over the boxes as it passes across the boxes and consolidates the felted sheet.

It is to be understood, of course, that the wire rolls 11 and 13 and

idler rolls

14 and 15 are all suitably mounted to the framework of the device, and that suitable provision is made for adjusting the mountings of these rolls whereby slack in the wire may be taken up, or the like, all as is common and well known. in connection with the manufacture of paper and fiber board.

The devices hereof which are provided for forming the fissured surface in the wet felted sheet comprise an. impression or scoring roll 20 and a screed assembly, all of which will be hereinafter described in detail. The operation of these devices, first, provide relatively shallow scores, impressions or cuts in the surface of the wet form sheet, which scores are impressed in an irregular pattern by scoring members mounted in the scoring roll 20, and' as a subsequent operation the Wet felted sheet passes under the screed member which, due to the frictional effect thereof, causes the surface portion of the board to be screeded or pulled apart, more or less following the patterns of the initial scoring of the surface, whereby such screeding results in the formation of irregularly placed and formed fissures opening from the surface of the sheet into the interior thereof. The scoring roll 20 is provided". with a shaft 21 which is mounted in mountings or supports 22, which supports 22 are in turn suitably mounted upon the framework of chest 10, all as is readily apparent in the drawings.

The screed device comprises mountings or brackets 27 which are also suitably mounted on the framework ofchest 10. A shaft 26 is mounted in brackets '27 and the screed blade is secured to such shaft 26 by means of suitable fastening devices, such as studs 35.

The screed blade is in fact of composite construction and comprises a relatively flexible sheet which may, preferably, be of stainless steel, but which, however, may be formed of a sheet of any suitable material, metal, plastic, or the like, and which base member is designated: by numeral 28. This member 28 is at its outer end slitted, as at 32, which slits extend from the outer edge thereof inwardly, and the outer edge is serrated, as at 31',

to provide" an irregularly shaped or outer edge, all as is 3 more particularly illustrated in Figure 8 of the drawing.

While the plate 28 is illustrated and has been described as a sheet of steel or the like, it is to be understood that this plate may comprise a number of relatively narrow, and separate portions, as, for example, each portion defined by adjacent slits might be a separate strip, or over the entire width the member 28 might be composed of, say, three or four or six separate strip-like portions, all of which, when assembled to shaft 26, provide a screed of the general form of the screed blade 28.

To stabilize the screed blade 28 there is provided an overlying plate 30 which is merely a rectangular strip of material, as, for example, a strip of steel or plastic or the like, and preferably there is interposed a thin rubber strip 29 between

members

28 and 30. The screed member, as will be evident, comprises the assemblage of the screed blade 28, plate 30, and interposed rubber sheet 29, secured in assembled relation, and to shaft 26 by studs 35 passing through suitable provided openings 34 in the various members and entering threaded openings 33 provided in shaft 26. It is, of course, evident that the structure just described provides a hinged or pivoted screed member which is flexible and has a serrated outer edge, and is downwardly inclined from its mounting, whereby the outer end of the screed is positioned at a more or less acute angle with the sheet against which the outer end of the screed bears. i

For varying the'pressure on the screed there is provided'a bracket 38 which extends across the width'of the fiber sheet, which bracket is suitably mounted on the structure of chest 10. The portion of the bracket 38 which extends across over the fiber sheet, is provided with threaded openings at intervals, and bolts or the like'39 may be threaded through such openings to project downwardly so that the bearings 40 on the lower ends of such bolts 39 press on the individual strips of the screed. By adjustment of the bolts 39 the pressure across the screed may be suitably varied so as to obtain the desired screeding action. The adjustable pressure members, bolts 39, just described are positioned over screed blades 28 at a point approximately two-thirds of the lengths of the blade measured from the pivot shaft 26. It will be realized, of course, that if there is no pressure on the screed the outer serrated ends of plate 28 will merely rest on the surface of the fiber sheet as it passes beneath the blade, and it will have no effect. If the screed blade 28 is pressed downwardly too heavily, then, of course, the still plastic sheet may be destroyed, that is, it may be pulled apart or broken up. It is obvious, however, that some intermediate pressure exerted on the screed by means of suitable adjustment. of screws 39 will cause a screeding action at the surface of the fiber sheet, and that by suitable adjustment of the pressure applied to the screed the partial separation or opening of the surface of the fiber sheet Will be obtained, as is illustrated in particular in the cross-section shown in Figure 5. Of course, for various purposes, different amounts and intensities of fissuring will be desired, andit will be understood that various adjustments ranging from no pressure exerted on the srceed blade, to such pressure as will break or destroy the fiber sheet, will progressively provide a heavier and heavier screeded sheet with the resultant formation of more and deeper fissuring of the surface portion of the fiber sheet as the pressure is increased. 7

The fiber sheet, when it reaches the outer end of the horizontal run of wire 12, may be carried by suitably mounted idler rolls 44 interposed between roller 13 and a take-01f conveyor roll 43, and thus the fiber sheet may be transferred from the wire 12 to a conveyor wire 43 running around conveyor roll 43. For imparting some smoothing action to the surface of the fiber sheet after it is'screeded, there may be provided a suitably mounted roll 45 which will serve to level the surface of the screeded sheet, but which roll, preferably, bears but lightly on the surface and merely exerts aslight levelling effect.

- made by the action of the scoring elements.

The scoring roll 20 may, of course, be of any suitable material with the scoring elements 23 provided either integrally or as separate elements mounted on and secured to the roll 20. A particularly satisfactory and adaptable roll has been found to be one made of wood in which there are driven portions of Acme corrugated fasteners in the particular illustration, there being used for this purpose half portions of 1 inch fasteners. These Acme cor; rugated fasteners are merely a convenient and readily available source for the scoring elements, but it will be understood that in lieu thereof other generally similar scoring elements may be used, and that such may be corrugated as are the Acme corrugated fasteners, or they may be straight or more or less slightly curved or shaped other than either straight or corrugated. These Acme corrugated fasteners are merely small corrugated steel members, conveniently for the purpose hereof 1 inch by 1 inch in size, and having one edge chamfered or cut diagonally or sharpened so that such edge more readily penetrates when the fastener is driven into wood. By the use of a wood roll 20, it is a relatively simple matter to change the pattern of fissuring by changing the pattern of the scoring elements 23 in roll 20. If the scoring elements are secured in 'roll 20 in a distributed arrangement, and in a generally more or less sinuous pattern, then fissuring as is illustrated in Figure 4 is obtained, since the fissures formed under the screed tend to follow the lines of penetration If it is desired that the fissures be more nearly straight across the sheet, then the arrangement of the scoring elements 23 should be in more nearly straight lines than in accordance with the pattern illustrated in Figure 3, or, if it is V desired that the fissures run generally diagonally across times advantageously employed just ahead of impression roll 20.

The operation of the above described device is considered to be clearly evident from the foregoing description when taken in connection with the drawings accompanying the specification, but a short rsum thereof is the conveyor, mounted over the conveyor and beyond the as follows:

A felted fiber board, which is formed on what is generally referred to as a modified Fourdn'nier machine, is de-watered on the screen, and by passage over suitably positioned vacuum boxes, and thereby somewhat compacted, this sheet is then subjected to further operations to provide the desired fissuring. The sheet just referred to passes under a scoring roll which is provided with a pattern of independent scoring elements which provide indentations or scores in the surface of the sheet, whereupon the sheet, then passing under a screed, is opened up, in its surface portions, by the action of the screed to provide a pattern of fissures in the surface portion of the sheet extending from the surface into the body of the sheet.

The apparatus hereof having been described in detail, together with a description of the operation thereof whereby those skilled in the art to which the invention apper tains may readily construct the apparatus and utilize the manufacturing processes thereof, I claim: A

1. Apparatus comprising a belt-like conveyor, positioned thereover and mounted for rotation, a cylindrical member, a plurality of substantially uniform thin and narrow projections extending beyond the surface of the cylindrical member, the projections positioned generally extending parallel to the axis of the cylinder and in substantially uniform spacing in broken, sinuous lines extending generally lengthwise of the cylinder and adapted to intrusively enter a plastic sheet passing thereunder on cylindrical member, and extending across the conveyor, 2. screeding device comprising a pivoted ,membermounted.

above and across the conveyor, a flexible and resilient blade mounted to the pivoted member, the blade, generally, in operative position making an acute angle with the conveyor, and adjustable pressure exerting means mounted over the blade and intermediate its ends and forcibly flexing the blade whereby the free end of the blade is flexed with respect to the remainder of the blade.

2. In the apparatus defined in claim 1, wherein the blade member, at its outer or free end, comprises a plurality of side by side strips, the outer or free ends of each of the side by side strips having a portion of the edge thereof forming an acute angle with respect to a line across the outer ends of the blade strips and adjacent such edges also forming obtuse angles, one with the respect to the other.

3. Apparatus for felting and fissuring a thick fiber sheet formed from a fiber suspension and including a traveling screen on which the fiber sheet is felted and suction boxes over which the felted sheet passes for dewatering, in combination with fissuring means positioned above the screen, beyond the dewatering station considered according to the direction of travel of the screen and extending transversely across the width of the screen, the said fissuring means comprising a cylinder, a plurality of bladelike elements projecting outwardly and substantially radially beyond the surface of the cylinder, the blade-like elements each of substantially equal width and projecting beyond the cylinder surface to substantially the same extent, arranged in groups positioned on spaced sinuous lines extending in general in the lengthwise direction of the cylinder and the blade-like elements substantially uniformly spaced along the such sinuous lines, the spacing thereof in excess of the width of the individual elements, and positioned above the screen, beyond the fissuring means, in the direction of travel of the screen, and extending substantially transversely across the width of the apparatus a screed device comprising thin flexible blade members, pivot means to which an end of a blade member is mounted and an adjustable blade flexing member mounted over and intermediate the length of the blade member and at an end contacting and pressing upon the blade member.

4. The method of fissuring a thick formed wet felted sheet comprising the steps; breaking the felted relation of the fibers of the sheet from the surface and inwardly thereof into the body of the sheet in a series of short spaced, irregularly positioned but generally transverse intrusions, and with relative movement in a direction substantially at right angles to the general direction of the breaks in the surface of the sheet, frictionally engaging the surface and by a screeding action expanding the transverse intrusions both transversely and longitudinally of the sheet to constitute elongated fissures extending from the surface of the sheet into the body of the sheet.

5. The method of fissuring felted sheet form fiber products and comprising the steps; forming a wet felted, drained and consolidated fiber sheet, intrusively penetrating such sheet at spaced positions therein from a surface of the sheet and into the body thereof to part the felted fibers and form isolated clefts in the felted body, screeding the pierced sheet in its lengthwise direction, thereby lengthening and opening the such individual clefts to constitute elongated fissures within the body of the sheet and drying the sheet.

6. The method of fissuring a plastic sheet comprising the steps; forming individual slit-like openings in the sheet from a face into the body thereof by intrusively piercing the sheet at spaced positions therein and screeding the pierced surface in the direction substantially transverse of the lengthwise dimensions of the slit-like openings, whereby the openings formed by piercing are enlarged widthwise and lengthwise to constitute screeds extending fi'om the surface of the sheet into the body thereof.

References Cited in the file of this patent UNITED STATES PATENTS 992,695 Smith et a1. May 16, 1911 1,508,087 Davies Sept. 9, 1924 1,854,230 Schur Apr. 19, 1932 1,883,526 Bryan Oct. 18, 1932 2,154,201 Frost Apr. 11, 1939 2,178,631 Frost Nov. 7, 1939 2,216,803 Benda Oct. 8, 1940 2,402,966 Linzell July 2, 1946 2,471,447 Perkins May 31, 1949