US1440914A - Runner for slide rules - Google Patents

Description

Jan. 2; 1923. v1,440,915 C. F. IECKMANN RUNNER.FOR SLIDE RULES. FILED rEB.25,192i.

HIIIIIIIIIIIIIE ATTKS? Patented Jan. 2, 1923.

UNITED STATES PATENTIoFFICI-z.

CARL F. DIECKMANN, OF CHICAGO, ILLINOIS, ASSIGNOR TO EUGENE DIETZGEN COMPANY, F CHICAGO, ILLINOIS, A CORPORATION 0F DELAWARE.

RUNNER FOR SLIDE RULES.

Application led February 25, 1921. Serial No. 447,713.

To all whmay t may concern:

Be it known that I, CARL F. DIECKMANN,

a citizen of the Ilnited States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Runners for Slide Rules, of which the following is a specification.

My invention relates to slide rules, and more particularly to the runners thereof. It is well known, of course, that the runners of slide rules have a reading line marked on the under side of a t-ransparent body for enabling the user to read the diferent scales in making his computations. Glass is often employed i'or the purpose, but slide rules are frequently dropped orstrike against surrounding objects, thus breaking the glass. It has been proposed to substitute (zelluloid, which is not brittle, but celluloid has two disadvantages. It is not :is clear as glass and this Vlack of transparency makes it more diiicult to make the readings accurately. A second disadvantage is that it scratches much more easily than glass and the surface soon becomes so abraded and roughened as to make the readings diicult. The object of my invention is to produce a runner which Will have the advantages of glass in clearly revealing the reading line, and will at the same time possess adequate strength and avoid the brittleness of glass.

I accomplish my object by the construction shown in the accompanying drawings, in which- Figure 1 is a top or face view of a runner embodying my invention, the same being shown in position upon a portion of a slide rule;

Figure 2 is an edge view of the parts shown in Figure 1.

Figure 3 is a sectional view on the line 3-3, Figure 1;

Figure 4; is a perspective view of the runner of the type shown in Figures 1 to 3.

y Figure 5 is a perspective view of a modified form of runner embodying the invention. and

Figure 6 is a sectional view on the line 6-6, Figure Like .numerals denote like parts throughout the several views.

First referring to the form shown in Figures 1 to et inclusive, the frame consists of under surface.

two channeled side bars l, having flanges 2 at the bottom adapted to slide in the grooves 3 in the edge of the slide rule 4l. It is desirable to provide a friction spring 6on the inside of one of the bars for retarding the sliding action of the runner and preventing the same from being accidentally displaced. f

.Extending across the rimner from one bar to the other, is a thin sheet 8 of Celluloid which has the reading line 10 marked on its The sheet is so mounted that it lies close to but out of actual contact with the upper surface of the rule. While the thickness of this sheet may be varied, it is desirable to make it quite thin; for illustration, about 15/1000 of an inch. A sheet as thin as this is virtually as transparent as glass and the thickness may be considerably increased without greatly decreasing the transparency.

Above this sheet of celluloid I mount a frame preferably of transparent or semitransparent material such as Celluloid, such frame having cross members 12 extending from one bar to the other and preferably integral with longitudinal bars 137 which, however, preferably do not project inward beyond the inner edges ofthe upper flanges 14 of the side bars. This frame performs two functions: First, it supplies the rigidity which the Celluloid sheet lacks, thus holding the side bars 1 properly spaced and with sufficient rigidity to frictionally engage the edges of the rule. Second, as they are preferably four or five sixty-fourths of an inch thick and are only about three-fourths of an inch apart, they serve as a guard to prevent external objects from reaching the surface of the celluloid and scratching it. In other words, the cross frame rigidifies the runner and protects the thin sheet of celluloid which carries the reading line.

In the form shown in Figures 1 to 4, the frame 12, 13 is originally a separate piece from the Celluloid sheet, although it mav afterwards be cemented to it. In the form shown in Figures 5 and 6, the frame and sheet are integral. The margins 16 are of the full thickness of the framefor example, four or five sixty-fourths of an inch or more, while the central portion 17 is hollowed down and thinned to such an eX- tent that the reading line beneath may be readily apparent, A cross element constructeffl. in this Way ot a single piece has substantially the same advantages as the type first described, and it also has the advantage of reducing the amount of time and workmanship required for nianuiiacture.

From the foregoing it `will be evident that as the centralv portion of the runner is thin, the reading line maybe distinctly seen- The rigidity is supplied by the thicker margins, which however, are `transparent to a degree making it possible to readily read the numbers marked on the scale. These numbers are larger and hence more easily read than the line scale markings and consequently the fact that the margins or' the runner are somewhat less transparent than the center does not prevent these numbers from beingread. Furthermore it is only occasionallyv necessary to read these scale numbers Where as the reading line is used for every computation. rlhus the runner is truly an open i'ace runner and possesses the necessary ri.- gidity in addition to the fact that the central portion, Where'the reading line is located, is highly transparent While the margins, although thicker, are rsudificientlj,7 transparent for all practical purposes.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

il. A runner for slide rules comp rising)Y opposed U-shape side bars adapted to respectively receive between their arms opposite edges of the slide rule, a cross member oi.: transparent Celluloid between the bars and disposed at its sides beneath the upper arms of the bars, and elements at the ends ot the cross member raised above the central portion of the upper surface thereof and serving in conjunction With the upper arms ot the bars to protect said surface or the CARL F. DIEUKMANN.

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