US 2235291 A
Description (OCR text may contain errors)
March 18, 1941. E. c. GAERTNER METHOD OF PRODUCING HOLLOW CLAY TILE Filed April 3, 1959 J26 A ORNEYJ.
E55 LLZ Patented Mar. 18, 1941 UNITED STATES 2,235,291 METHOD OF raon rgmo HOLLOW CLAY Edward C. Gaertner, Terre Haute, Ind., assignor, by mesne assignments, to Reconstruction Finance Corporation, Chicago, 111., a corporation of the United States Application April 3, 1939, SerialNo. 265,690
This invention relates to a method of producing a vitrified clay product.
The chief object of this invention is to elimi-' nate in clay products for permanent, sanitary and decorative wall finish purposes, certain objections heretofore inherent therein and to obtain new and desirable features.
One of the chief objections to present clay ware is that it must be sold with certain tolerances, now accepted by the architects as a necessary evil. The present invention eliminates this objection.
Another chief objection to large size present clay Ware is that it has plane distortion. The present invention eliminates this objection as well.
In addition to the aforesaid objections, present ware production has an unavoidable wastage incident to handling deformation that results in deformed finished ware unacceptable for normal use. The present inventionreduces this objection to .a minimum and to a calculatable positive amount, and at little additional cost as will hereinafter more fully appear.
The present invention is'also-capable of including a finished or glazed face, or faces, if, as and when desired.
The full nature of the invention will be understood from the accompanying drawing and the following description and claims:
In the drawing,
Fig. 1 is a perspective view of the vitrified log from which the finished clay units are fabricated.
Fig. 2 is a similar view of a modified form of log.
For a better understanding of this invention, it is set forth that heretofore clay ware has been produced in the approximate form and size in the green state and then burned to vitrification. Exposed surfaces may be supplied with glaze finish material and fused thereto in the initial burning of the unit.
The resulting ware, due to inherent shrinkage, will vary not only as to size but shape as well. Also the'vitrified ware will have included therein all other deformations incident to green ware handling. This wastage alone is considerable and variable.
The present invention, in brief, contemplates the formation of a very large unit in green form, burning to vitrification, and then cutting to size and form. The log, when vitrified, is in such shape and size that it can be sawed with a minimum amount of wastage incident to truing and kerfing.
The ware may be of acoustical or glazed face character, as desired. In the drawing, each figure is to scale. Fig. 1 illustrates in perspective a log which has been formed in the following manner:
The raw clay is processed in the usualmanner and homogeneously mixed therewith is a combustible material in finely divided form. This may be coal, sawdust, corn husks, and the like.
This mixture is extruded from a die in the usual manner and the clay column is cut to the desired length.
By way of illustration, the length selected is such that when burned tovitrification, a 38" log provides a 36" length with finished end faces and which can be reduced to lengths of 3", 4", 6", 8", 12", 15" and 18", et cetera, lengths, providing the desired number of desired length units of ware. Of course, when out to 3?, 4", 6", 9", 12" and 18'7, the log will form a plurality of like length'units.
Similarly, the log when vitrified is about 16 /4" on a side. This provides units of 1% and 3%" thickness and 12" in width and four corner units 1%" x 1%" finished two faces. The four 12" x 1% side units are finished three faces. The three central 12" x 3%" units are finished four faces. The length of these several units may be that selected and as designated above.
The green log is burned to vitrification. In so doing, the combustiblematerial is burned out leaving small voids in the ware providing a cellular ware suitable for acoustical purposes. Also this type of vitrified log readily lends itself to rapid reduction by a patentable sawing machine.
Inherently this machine includes a plurality of parallel sawing elements so that a plurality of cuttings can be simultaneously effected as the log or .ware is presented thereto or the saws are caused to move into the work. Each saw cuts a kerf of not more than 1% width and opposed faces are parallel, smooth and coplanar throughout.
It will be understood the rough log (vitrified) in its exposed faces, ends, and edges contains all imperfections incident to the handling, et cetera, of the green. log prior to and during vitrification. Also all deformation, such as due to shrinkage, plane distortion. and the like during vitrification is, of course, multiplied in the resultant log by reason of its large size. For this reason large sizestandard ware is economically impossible to produce for structural use. This means more or larger mortar joints in the finished structure, because of the use of smaller units in the present standard practice or the irregularities therein and especially units of larger sizes necessitate larger joints. The various designs of large cells in their arrangement permit the formation of cavities resulting in light weight or non-solid cellular ware. This also facilitates and expedites thereduction of the log into finished units.
In Fig. 1, the unfinished vitrified log is designated by the letter A. The log is then simultaneously slabbed' as indicated at B and B These kerfs extend the full length of the log and full width of the same. This provides planks C and C and the intermediate portion C Portion C is then simultaneously kerfed as at D, D D and D This forms two end planks E and E and three central units E E and E The plank C is kerfed at F and F forming unit G and corner units G and G Similarly, plank C is kerfed at H and H forming unit J and. corner units J and J All corner units are approximately 1%" x 1%".
All plank units are approximately 1% x 12"..
The central units are exactly 3%" x 12". Each corner unit has no cavity. Each plank unit includes three sequentially arranged longitudinally aligned cavities K. Each of the master or central units includes three sequentially arranged and longitudinally aligned cavities L. Cavities K have one dimension, the same as cavities L. The other dimension obviously is less than half the other dimension of cavity L due to the necessity for providing an exterior Wall.
All walls between finished faces and cavities have sufiicient thickness. These are not uniform in thickness because in the reduction of an irregular log to the true units, the cavities do not always exactly center in the unit.
Preferably, all these operations are performed before the ends are trimmed and the trimmed lengths are reduced to proper length. The end cuttings are indicated by letters N and. N and the length cuttings by O' and O Herein such cuttings provide 12" length units.
Should the log have a deformity of an excessive size, it will be obvious that the particular plank unit or corner unit may be discarded. If the end be unduly deformed, it will be obvious the 36" length can be shifted from that end toward the opposite end.
Also any standard 12" unit could be reduced to 3", 4", 6", 8" or 9" length for extra smaller size units, the deformed portion being discarded.
Each of the triple cavity units may be reduced on the job by a smaller size saw to form single cavity and single and double cavity units. Also each central unit can be readily divided forming units finished on three faces and an unfinished and irregular fourth or back face. Such reductions are indicated by dotted lines P and Q in Fig. 1.
In Fig. 2 there is illustrated a modified form of log. Herein dual letters, similar to the single letters, are employed to designate parts, et cetera, like or similar to those singularly designated in Fig. 1. For clearance, however, many reference letters are omitted in Fig. 2.
In Fig. 2 plank units EE' and EE have end cavities KK smaller than cavities KK. This leaves an end portion RR at either end (the latter being illustrated) which may be reduced as at SS to provide an angular face, or faces, respectively.
In like manner, central units EE and EE have cavities LL smaller than cavities LL and one wall is biased as indicated at LL providing portion TT. at either or both ends (the latter being illus-. trated) which may be reduced as at UU to provide an angular face, or faces, respectively.
This brief reference to the form of log illustrated in Fig. 2 it is believed is sufficient for an understanding of the invention, it being understood that log AA is fabricated in exactly the same manner as log A.
Whenever it is desired to provide glazed ware, the units after formation to. the size selected have the faces to be coated supplied with glaze material which matures at a temperature below that of vitrification. Usually a filler coat and then a final coat is applied, the latter immediately following filler coat application. The coated ware is then fired at a temperature suflicient to mature the, glaze finish but below that of vitrification, so that deformation of the unit is impossible. The breakage loss in handling is substantially the only loss which occurs and this negligible since the ware is not green. With but slight care, no wastage incidental to glazing will occur.
From the foregoing it will be obvious that from the log approximately the maximum amount of surface ware, true to form and the like, can be obtained with a minimum of loss.
The ware factory can produce large numbers of logs and subsequently fabricate same to the desired and required sizes of units. This eliminates the necessity of carrying stocks of different vitreous clay ware. thereby reducing inventories and smoothing out the plant production curve. Other advantages and economies will be obvious from the foregoing.
A comparative table is set forth which is by no Characteristic g sg g zsgg gl Invention ware Weight Min. 27# per sq. ft. 4. Max. 13# per sq. ft. 4". Strength Beyond all load bear- Beyond all load bearing code requireing code requirements. ments.
Size 2% x 8, 5 x 8, 5 x 12 and All the foregoing plus 8x16. 6x12,12x12,12x24,
12 x 36 and larger. Size variation Approx. )4" per lineal Less than him in 36'.
oo Colors Limited to those ma- Unlimited.
turing at high temperatures.
Textures All glazed textures. All glazed textures plus an unglazed acoustical texture if desired.
Kiln recovery .A" Max. Anticipated min. of
grade of finished ware.
Reclamation ofofi Practically none. Sold 75% by cutting defecgrade ware. at greatly reduced tive portions out of sizes.
Delivery time Generally3to4weeks 7days.
from date of orunless tremendous der. invientories are carrie Inventories Varies in A grade. Predetermined quan- Usually great voltity of logs. Fmume of slow moving ished stock A grade ofi grades. on order only and no oil? grades.
Packing 33% sav1ng.
Freight and cart- Savings in direct relaage. tion to weight.
Damage in transit Practically total loss High percentages reor on jo because of difficulty claimed by easy cutin cutting. ting to short lengths.
Cutting or iabri- Slow and costly Fast and at low cost.
$4 to Uniform 54; or less. Relatively slow, ac- Fast because of high count low absorpabsorption of bed. tion of bed. Cost of labor of In relation to size, the In relation to size; the setting. larger the unit the larger the unit the less per sq. ft. less per sq. it.
A unit thus specifically described produces about 30 sq. ft. of wall surface, which with labor at 60-cents per hour, costs between $3.25 and $3.50 when properly out and glazed, if desired. The usual cost for this amount of ware of. transportation, selling and erection is about $200. The usual cost of an equivalent amount of standard ware is between $15.00 to $18.00 although in a. recent instance same was sold at $12.00. If the ing and erection will be more than that of the.
present invention, and the lower price be used for comparison, in situ, sq. ft. of the invention will cost $5.50 as against $15.00. This saving means that this new ware is capable of competing on a more favorable basis with other structural constructions, such as brick, or tile covered surfaces, or glass covered surfaces and in its own field will offer an enormous saving for those using this type of construction.
By the term closed tubular in the claims, it is to be understood that the tube forming opening wall includes no lateral rupture or opening to the tubularity and does not refer to the ends of the tubular structure.
While the invention has been illustrated and described in great detail in the drawing and foregoing description, the same is to be considered as illustrative and not restrictive in character.
The several modifications described herein as well as others which will readily suggest themselves to persons skilled in this art, all are considered to be within the broad scope of the invention, reference being had to the appended claims.
The invention claimed is:
1. An improved method of producing structural clay ware and the like, including forming an elongated "green log 0! a homogeneous mixture and the desired dimensions and including spaced cavities extending longitudinally there-- through, burning the log to vitrification to produce a readily severable product, and then longitudinally severing the log cavity forming wall between adjacent cavities without exposing the latter, and between the ends by sawing to form finished face, closed, tubular units, some of which are all finished and others of which are finished on all but one or two Iaces.
' 2. A method as defined by claim 1, characterized by arranging the cavities in the log such that upon severance into units each unit except the comer unit includes a plurality of sequentially aligned cavities, and then longitudinally severing each unit between adjacent cavities without exposing the latter to form smaller, finished face,
closed, tubular units.
. 3. A method as defined by claim 1, characterized by arranging the cavities in the log such that upon severance into units each unit except the corner units includes a plurality of sequentially aligned cavities, certain unit end cavities being smaller than others, and then bias severing the unit adjacent the smaller cavity without exposing same.
EDWARD C. GAERTNER.