US2171873A - Calculator - Google Patents

Description

S, G. GOULD Sept. 5, 1939.

CALCULATOR Filed sept. 15, 1958 on: annu 000m 3230 n mmool.

Patented Sept. 5, 1939 UNITED STATES PATENT OFFICE y CALCULATOR Stephen G. Gould, Kirkwood, Mo., assignor to Missouri Portland Cement Company, St. Louis, Mo., a corporation of Missouri Application September 15, 1938, Serial No. 230,053

3 Claims. (Cl. 235-89) This invention relates generally to calculators, latcr constructed in accordance with the present and particularly to calculators of a character invention, the slide being extended downwardly.

adapted for calculating data with reference to Figure 2 is a view similar to Figure 1 showing concrete mixtures and the physical properties to the reverse side of the calculator shown in Fig- 5 be expected therefrom. ure 1. g 5

In calculators which have heretofore been pro- Figure 3 is a sectional view taken along line posed for determining the various characteristics 3-3 of Figure 1. and properties of concrete mixes some diiliculty In accordance with this invention, a calculator and confusion has been experienced among the of the slide rule type is provided for determining l users. For example, in determining the strength data with reference to concrete. In View of the 10 to be expected from a given concrete mixture, as fact that the strength of a given concrete mix for example the familiar 1-2-4 mixture, wherevaries inversely as the water content thereof, the in to each sack of cement there is employed two calculator of the present invention is arranged cubic feet of sand and four cubic feet of coarse to indicate the strengths from concrete mixes of l5 aggregate, the strength to be expected depends various water contents. In order to determine 15 not only upon the type of cement employed, but the Water content of a given mix, such as a standupon the water content of the mixture. With a ard 1-2-4 mix,`however, a series of figures is given type of cement the strength of a given provided for indicating the quantity of water remixture will vary inversely as the water content. quired to make such a mix stiff, medium or wet,

In calculating concrete data, however, it is often depending upon the consistency desired. When 20 imperative that the calculator give consideration the amount of water has thus been determined to the consistency of the concrete mixture, and from one reading of the rule, the present invensince this consideration is dependent upon the tion contemplates that the rule be reset in order water content a factor enters which may upset to read the strength corresponding to the sethe other calculations unless due account is taken. lected water content. An especial feature of the 25 Likewise with a given concrete mix and a given present invention is the arrangement of characconsistency the strength to be expected will be ters and windows on the slide and envelope, redifferent in the case of ordinary Portland cement spectively, in such manner that when the rule from the case of high-early strength cement. is being read to determine a water content, no

' Accordingly, difficulties have been encountered strength can be read but that the rule must be 30 in reducing to the form of a simple calculator reset in order to permitastrength reading. Likethe data necessary for determining the physical wise, when the rule is in position so that a properties to be expected from concrete, and yet strength reading can be made the characters for take into account all of the usual variables. determining water content are blinded. In ac- 3,; While efforts have heretofore been made to procordance with the embodiment illustrated in the duce calculators of a character suitable for caldrawing, this result is accomplished by Slightly culating concrete data, they have not heretofore offsetting the columns of gures on one side of been reduced to such form that inadvertent misthe slide from the columns of figures on the readings were not liable to be made. other side of the slide so as to require a longi- The object of the present invention, generally tudinal movement of the slide between a position 40 stated, is to provide a calculator of the character Where the gures on one side may be read and a referred to wherein the possibility of inadvertent position where the figures on the other side may misreadings is substantially obviated. be read.

A more specic object of the present invention Referring now to the drawing for an illustrais to provide a calculator for concrete mixes and tive embodiment, the calculator of the present 45 the properties thereof, wherein the strength of invention may COmDI'iSe an 11V10p6 Which the various concrete mixes is clearly and unmismay be made of pyroxylin, metal, or any other takably designated Without reference to the consuitablematerial, as provided. Fitted Within the sistency of the mix, but only with reference to envelope I is a slide 2 arranged to slide freely the water content of the mix. back and forth through the envelope endwise. 50

Other objects will become apparent to those Arranged upon the front side of the envelope l, skilled in the art when the following description as shown in Figure 1, is a. series of windows 3, 4, is read in connection with the accompanying 5, 6. The window 3 is arranged to cooperate with drawing, in which: three longitudinally extending series of figures on Figure 1 is a plan view of the front of a calcuthe front surface of the slide 3 for indicating the 55 variousr standard or common cement mixes, such as the 1-11/2-3 appearingin the drawing. Similarly a longitudinally extending series of figures is arranged on slide 2 to appear through window 4, and indicate the number of pounds of sand and coarse aggregate required per sack of cement for the mix shown at window 3. Likewise, a longitudinally extending series of figures visible at window 5 indicates the number oi' sacks of cement required to make a cubic yard of concrete and the number of c`ubic feet of concrete produced from one `sack of cement with the mix as shown at window 3.

A further set of three series of figures extending longitudinally of slide 2 on the front thereof is visible at window 6 and indicates respectively the number of gallons of water per sack of cement required to make a concrete of the desired consistency whether stiff, medium or wet.

It will be observed that when the slide is in the position shown in Figure 1 with the figures alined so as to be readable through the windows .3, 4, 5 and 6, the figures on the other side of the slide, as shown in Figure 2, are blinded. In order to accomplish this a plurality of Windows 1, 8, 9. I

I0, II, and I2 are arranged on the reverse side of envelope I in such manner with reference to the columns of gures on the reverse side of the slide 2 that when the figures on the front of the slide are alined with the windows 3, 4, 5, and 6, the gures on the reverse side will not be alined, but on the contrary, will be blinded by the windows 1, 8, 9, I0, I I; I2. In the embodiment shown in the drawing, the window 1 is arranged in alinement with the line of Windows 3, 4, 5, and 6 on the front of the envelope, but the column of Windows 8, 9 is displaced to the left and the column of windows I0, II and I2 displacedl to the right of window 1, a distance corresponding to the distance between the columns of figures on the slide 2.

While in the embodiment, as shown in the drawing, the window spaces 3, 4, 5, 6, 1, 8, 9, I Il, II and I2 are shown as perforations through the material of the envelope I, it will be understood that an imperforate structure may be employed when the material is of such character as to permit that it be made transparent at the Window spaces, but opaque elsewhere.

With this arrangement of parts when the slide is in position so as to permit a reading on the front of the device, no reading can be made on the back. This assures that when a water content strength reading can be made. Data foraindicating the strength of cement mixes in accordance with the water content thereof is shown at windows 8, 9, III, II and I2. The windows 8 and 9 may be arranged in coordination with a pair of longitudinally extending series of figures I8 and I9 to indicate the strength of concrete mixes in which one type of cement, for example ordinary Portland, cement is employed. With cement of the high-early strength type, however, at the same water content diiferent `strengths may be expected, and consequently the longitudinally extending series of iigures 20, 2|, 22, 23 are arranged so as to be visible, respectively, through windows I0, II, and I2. It will be observed that windows 8 and 9 are arranged in staggered relation with reference to windows I 0, II, and I2 so that a given longitudinal series of figures on slide 2 may be visible through but one of the winto more clearly distinguish between the figures which are intended to be read at windows 8 and 9 for ordinary Portland cement and the gures which are to be read at windows IIJ, II, and I2 for high-early strength cement, those of series I8 and I9 may be printed in one color and those of series 20, 2| 22, 23 in another color.

In the use of the calculator of the present invention the specified mixes may be set at window 3, as for example the 1-11/2-3 mix shown in the drawing. If it is desired to make this mix of a medium consistency it will be observed that five gallons of water per sack of cement will be required. 'Ihen in order to determine the strength to be expected from such a mix the slide is moved so as to set 5 at window 1. With this setting accomplished, the seven and twentyeight days strength of such a mixture made with an ordinary Portland cement will be indicated at Windows 8 and 9, respectively, and the one, two, seven and twenty-eight days strength of such a mixture made with high-early strength cement will be indicated at windows IIJ, II and I2. It is frequently desired to work backwards from a required stength and to determine not only the consistency, but the mix necessary to give a required strength. In such case the required strength may be set at Window 9, for instance, the number of gallons of water corresponding to that strength read at window 1, the rule reversed and the slide manipulated, so as to locate the water value just read from Window 1, in position in window 5 corresponding to the desired con-A sistency. When this setting is accomplished reference to window 3 will indicate the mix to be employed.

Y The arrangement of the gures on the opposite sides of the slide in such coordination with their respective windows as to obscure or interfere with proper reading'of the slide on one side, when it is set for reading on the other side, minimizes the likelihood of making misreadings from the device, and also reduces the number of windows which would otherwise be necessary, and which if present would also contribute to the likelihood of misreadings. Since for each diiferent water content of the concrete mixture a total of six strength readings are available, and since for each different mix three diierent water contents are available, confusion would occur if the strength readings appeared automatically upon setting the device for a given mix. In the arrangement disclosed, however, a resetting'of the device is compelled before the strength" corresponding to any given mix may be ascertained,

and since the resetting is compulsory, there is -calculator is provided which may be manipulated in a facile and convenient manner without liability to inadvertent misreadings. While in the foregoing description reference has been made to various details of the device, and'- especially to the fact that the squares and Windows are arranged With such reference to each other that when the rule is set for reading on its velope mutually oset.

front, it cannot be read on its reverse side, and it is also pointed out that this result could be accomplished by offsetting the columns of ilgures on the back from the corresponding columns of iigures on the front, it is evident, of course, that the same result could be accomplished with the columns on the front and back of the slide in alinement, but with the windows in the en- Other comparable rearrangements and reversal of parts may be made within the spirit of the invention by those skilled in the art. It is to be distinctly understood, therefore, that such modifications, rearrangements, and adaptations of the features of the calculator hereinbefore described, as do not depart from the spirit of this invention are, although not specifically described herein, contemplated by and within the scope of the appended claims.

Having thus described claimed is:

1. A calculator of the kind described, comprising, an envelope having windows in opposite sides thereof, a slide movable in said envelope and having characters on both sides thereof arranged to be read through the windows in said envelope, the windows and characters on one side being so positioned relative to the windows the invention, what is and characters on the opposite side that when the characters of the slide are alined with the Windows on one side they are disalined with the Windows on the opposite side of the envelope.

2. A calculator of the kind described, comprising, an enevlope having Windows in opposite sides thereof, a slide movable in said envelope and having a plurality of columns of figures arranged on both sides thereof for selective reading through the windows, said columns of figures on the slide being transversely disalined front and back so as to compel resetting of the slide between readings on the opposite sides thereof and the windows on opposite sides of the envelope being so positioned with respect to the columns of figures on the respective sides of the slide as to interfere with proper reading of the figures on one side when those on the other side are alined with their corresponding windows.

3. A calculator for concrete mixes comprising, a slide having a plurality of longitudinally extending scales on each side, and an envelope having windows arranged to cooperate one with each scale, the windows on the respective sides being arranged so as to interfere with proper reading the scales on one side when those on the other side are readable.

STEPHEN G. GOULD.

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