US2591414A - Form for use inmaking cementfiber boards - Google Patents

Description

April 1, 1952 A. ELMENDORF FORM FOR USE IN MAKING CEMENTFIBER BOARDS Filed Aug. 5

m l 7b?? JZ @raga Patented Apr. l, 1952 FORM Fo-usEIN MAK-iNdfcEMETA FIBER Bomans 1 t The present invention relates to` forms' or molds particularly adapted for use in a continuous process of making so-calledcement-,fiber board, although it is not confined to that specific use.

The primary purpose of the inventiontis to permit wood or other organic flbersthat maybe several inches long and are coated with a Portland cement or gypsum binder to be fashioned into board material of predetermined width `and indefinite length which is cut into individual panel lengths; each panel remaining-in an individual form until cured or set. In this way every panel may be of uniform texture from one end to the other and, after being molded,` it is protected against damage until it becomes strong and-hard. Due to the nature of the forms used heretofore for such products there have always been large variations in the texture and density of the individual boards or panels at their'4 ends and edges; Aand therefore such boards have not beencommercially satisfactory.

In carrying Vout my invention I construct a formcomposed of only a bottom Wall fand two parallel side walls, so` that the mold cavity is open-at the top and at both ends. Anynumber of forms may be placed end to end to provide a troughof any desired length. The forms are so constructed that the continuous sheet maybe cut across the width thereof by rapidly `moving sawsat the meeting lines of consecutive forms, thereby leaving in each individual form an individual panel with perfect, square end edge faces. These forms may then be Vplaced in stacks, with each form serving'as a caul to compress the panel in the next lower forin until it has a predetermined thickness which is maintained until the nal setting and hardening of the binder.V

The various features of novelty whereby the present invention is characterized will hereinafter be pointed out with particularity in the claims-but, for a full understanding of theinvention and of its objects andadvantages, reference may-be had to the following detailedldescription` taken in connection with the accompanying drawing, wherein:

.Figure 1 is an end View of one-of my improved forms or molds-with the center broken out; Fig. 2 is a top plan view of such form, broken out at boththe longitudinal and transverse centers; Fig. .3' is `an end view of two forms that have been filled and are positioned one upon theother to start' the building of a stack, only a fragment of each form being shown; Fig. 4 is a top plan view showing. on a much smaller scale, a plurality of the forms arranged end to end to create a single, l

long trough-like form; Fig. 5 is a side `view, on the same scaleas Figs. 1-3, showing fragments of two of the forms which meet in Fig. 4; Fig. `6 is an end view of a fragmentV of a form provided with aI wear-resisting lining; and Fig. v'I is an end view of `a fragment of another modified form.

Each form is composed of a flat bottom wall I and two parallel side walls, 2 `and 3. The side walls are preferably 'sturdyledges or bars and are somewhatv shorter` than` the bottom wall. In the arrangement shown the side walls terminate at equal distances from the ends of the bottom wall. Therefore,` when two of the forms are placedend to end,fregardless of which end of one meetsthe other form,'sirnilar` slots or gaps, 4, 4, respectively, appear inthe side walls of the composite form,V directly opposite each other. The bottom ,wall isxpreferably rabbeted transversely beyond the ends of the side walls, as at 5, so that whentwo forms vare placedend to end, the slots 4 are, inH effect, continued down into the 'bottom wall of the composite mold. Withthis arrangement the saw teeth may project down below the lower lface Vof the mat duringthe sawingoperations. M

In the under sideof the bottom wall are rabbetsA 'that reduce the marginali portions la; at opposite sides, in thickness over widths equal to the" widths ofthe side' walls; thereby jleaving intact the largecentral part `Il that is just as wide asV the internal width of the form. The part vIb may therefore'be `regarded as` a downward-projection on' thebottomwall adapted toenter a i like `.form whenl'the two forms are set One-on the other; and themarginal portions la may beregarded` as shoulderson the upper of two forms, adaptedvto rest on top ofi the side walls of the under form.

The. height' of the sidewalls is equal to the thickness of the panel'to be'molded, plus the thicknessof the downward projection Ib. There-J fore,.whena formis nested in another, the effective mold cavity in the lower form has exactly the same' cross-sectional shape and area as doesU the product to bemade;^V andthe bottom of the upper form' constitutes acaul tobeardo'wn on and effect the" desiredcompression 'of `a rudimentary panel inthe lower form.

The molds areintended to vbe `placed end tov end in a machine that movesthe composite form lengthwisey while a, continuous mat of cementcoated -bersis built up therein; 1 Then,` 4as each individual:formureaches' a predetermined position, the mat is severed transversely between* that form and the next one. The freed form may then be removed and an Vempty form be added at the trailing end` of the line of forms. Each form so removed carries a rudimentary panel with it. Then, when the removed forms are stacked upon each other, the iinal shaping of the panels completes itself. The panels are taken out of the forms only when they have become firm and hard.

VBecause cements, such as Portland cement and gypsum, set due to the formation of crystals from an aqueous solution thereof, there has been a generally accepted belief that cement "fiber board, using such cements, cannot be made commercially as continuous mats which are then cut into panel lengths; for the reason that substantial setting of the cement, beforesetting, was

deemed essential. I have found, however, that by using my long, slotted form and a rapidly moving saw, panel-length sections may be cut off squarely and cleanly as soon as they have been molded into shape.

At the time a panel is severed from the mat it should be substantially thicker than the finished product. In Fig. 3 the rudimentarypanel A in the upper form is shown as'being thick enough to protrude a little through the top of the form. The panel A1 in the lower form, on the other hand, has been compressed to give it the thickness which the finished product is intended to have. WhenV a third form is added to the stack, panel A will be compressed thereby -to the same thickness as panel A1. Since only the end edges of the panels l are left exposed when molds containing panels are stacked, cement mortar may be trowelled into such edges, preferably immediately after stacking; thereby preventing undue loss of moisture while setting and leaving the edge facesv less fibrous than before.

The form is preferably made of wood and, to facilitate 4the removal of panels therefrom, the inner surfaces may be oiled as in conventional concrete form work. On the other hand, the' interior of the form, especially the bottom wall, may have its inner surfaces composed of a hard plastic, such as a phenol-formaldehyde overlay, that does not adhere to the cement. In Fig. 6 there is such a lining or overlay 6 on all'interior surfaces of the form. If desired, the form may be so constructed that the bottomk wall constitutes a tie between the two sidev walls of the next lower form in a stack. Thus, as shown in Fig. 7, the top of each side wall is cut away along the outer edge over a substantial width, as at 1a, thereby leaving an upstanding rib 1b along the inner edge. Each part 8a of the bottom wall, corresponding to part Ia in the first species, has along its outer edge a downwardly projecting rib 8, that is just as wide and as deep as the excision in the top of the overlying side wall. When forms are stacked the parts 8a rest on ribs 1b of the next lower form, while ribs 8 rest on the depressed vsurfaces Ia of the latter form.

It will therefore-be seen that I have created a novel form or 'mold thatmakes possible the production of cement-liber board panels in a unique and eiicient way, and insures that the texture at the ends of each panel is the same as elsewhere throughout the length of the panel; this being due to the fact that the panels are not molded individually but as part of a continuous mat, along with the further fact that each panel may remainA in an individual mold until it is a fmished product.

I claim:

1. An open ended form for use in manufacturing cement-fiber board, consisting of a bottom wall having square ends and two parallel side walls that are somewhat higher than the thickness of the board to be produced, the side walls being slightly shorter than the bottom wall, the bottom Ywall having on the yunder side a downwardly protruding portion as wide as the distance between the side walls; and the thickness of said protruding portion being equal to the difference between the height of the side walls and the thickness of said board.

2. A form as set forth in claim 1, wherein each side wall is symmetrically disposed with respect to the bottom wall, whereby, whenever two forms are set end to end and filled with cement-fiber mixture, there is in each composite side wall a slot directly opposite the slot in the other composite wall, thereby permitting a saw to be moved crosswise of the forms through the slots to sever a board that Vextends through both forms.

3. An open-ended form for use in manufacturing cement fiber board, consisting of a bottom wall having square ends and two side walls each of which is slightly shorter than the bottom wall whereby, when two such forms are placed end to end, a, slot is created between each side wall in one form and the near end of thecorresponding side wall in the other form ata time when the two bottom walls are touching each other to form a continuous wall, wherein the under side of the bottom wall is shaped to fit over the top and down both the inner and outer sides of the side walls of a like mold when two such molds are placed one on top of the other.

4. An open-ended form for use in manufacturing cement fiber board, consisting of albottom wall and two side walls each of which is slightly shorter than the bottom wall whereby, when two such forms are placed end to end, a slot is created between each side wall in one form and the corresponding wall in the other form at the time the two bottom walls are contacting each other, wherein the bottom wall containsV in the top, beyond the ends of the `side walls, transverse rabbets for creating downward extensions of the slots between the opposed ends-of the two meeting forms. Y

ARMIN ELMENDQRF. REFERENCES CITED The following references are of record in the le of this patent;

UNITED STATES PATENTS Number Name Date 296,825 Du Pu7 Apr. 15, y1884: 613,085 Smith Oct. 25,Y 1898 771,011 Hayward "Sept. 27, 1904 841,749 Wells et al. Jan. 22,1907 855,084 Zurbuch May 28, 1907 855,633 Herring June 4, 1907 928,078 Spear July 13, 1909 1,019,250 Herzberg et al Mar. 5, 1912 1,111,567 Murguiondo Sept. 22,1914 1,562,519 Ruppel Nov'. 24, 1925 FOREIGN PATENTS t Y Number Country Date 7,670 France Nov. 18, 1845 1,371 Great Britain 1884 V29,9041 Germany Dec. 23, 1884

Images