US254980A - Surveyor s self-reading level-rod - Google Patents

Description

- (NoModeL) T. M. JACKSON.

SURVEYORS SELF RBADING LEVELRO D.

Nor-254,980. 7

Patented Mar. 14, I882.

UNITED" STATES:

PATENT OFFICE.

THOMASM. JACKSON, OF OLARKSBURG, WEST VIRGINIA.

SURVEYORS SIELF-READIING LEVEL-ROD.

SPECIFICATION forming part of Letters Patent No. 254,980, dated March 14, 1882.

I Application filed November 10, 1881. (No model.)

To all whom it may concern:

Be it known that I, THOMAS M. JACKSON, of Olarksburg. in the county of Harrison and State of West Virginia, have invented certain new and useful Improvements in Surveyors Self-Readin g Level-Rods; and I do hereby declare that the following is a full,clear, and exact description thereof, reference being bad to the accompanying drawings, and to the letters of reference marked thereon, which form part ofthis specification, in which Figure l is a front view of a section of my improved staff, showing part ofits graduated face, full size. Fig. 2 is a cross-section. Fig. 3 shows two sections of the face of the staff, more fully exemplifying my mode of graduating the same. Fig. 4 is a front view. Fig. 5 is an edge view of the full rod, showing the back swell.

This invention relates to improvements in.

rods or staffs which are used by engineers for leveling.

Myinvention consists in a novel construction of the leveling-rod, whereby it is stiEfened,'preventing it from warping, and the graduation marks on one of its surfaces are guarded from injury by the bruising of the straight-edge of the rod, as will be hereinafter fully explained.

I prefer to construct the rodA of clear,wellseasoned white pine, sixteen feet long. It is straightion the left orgraduated edge a, but increases in width from the lower end of the right-handedge, c, to the center, and diminishes from this point to its top, as shown in Fig. at. The graduated face is flat and perfectly smooth, but the back swells from the ends to the center similar to the right-hand edge, 0. This swelling of the rod from ends to center stiffens it, preserves it straight, and admits of its use as a measuring-pole as well as a leveling-rod. The bottom of rod A is shod with metal, so as to inelose its end and prevent undue wear and battering when subjected to rough usage,and the front of the straight edge is beveled, as shown in Figs. 1, 2, and 3, for the purpose of guarding the graduated edge a and preventing it from being bruised or the graduating-marks marred or obliterated. I prefer to paint the rod white, and on this white background I paint the gratluations or divisions, and cover the same with a suitable transparent varnish. The rod is marked off in feet, sixteen in all, beginning at the bottom and numbering upward, each foot-figure beingtwotenths ofafoot high and marked distinctly with abrightred color. The exact foot-marks are at the top of each footfigurc, and indicated by a black transverse line extending across the rod. Each foot is divided into ten equal parts, and each even tenth is numbered by the even fig tires 2 4 6 8, their tops indicating the exact mark and the intermediate spacesindicating odd tenths. Again, each tenth is subdivided into ten equal parts by alternate black and white bars or stripes, varying in length, so that the eye can readily detect them. It will be seen by reference to Figs.1 and 3 that the bars are longer at the center, and that the exact center of each tenth is marked by an arrowhead. is one-hundred th of a foot wide, and the top of each bar indicates the even number of hundredths-2 4 6 8-while the bottoms of the bars or tops of the spaces give the odd num bers-viz., 1 3 5 7 9. It will thus be seen that the division-marks read to one-hundredth of a foot, making it very accurate by the graduations themselves, and avoiding the guessing at fractions, as these, to the extent named, are actually read directly on the rod.

It will be observed that all of the blank tenths are odd, and all blank hundredths are odd, so thatin reading the rod through the instrument the black spaces indicate the even tenths and the white spaces the odd tenths, thus rendering the calculation exceedingly simple and the taking of the observation very clear. Each figure should be read at its exact top-thatis, in lookingthrough the instrument at the rod the correct reading is thatlyingimmediately below the horizontal cross-hair. To illustrate this, suppose, for example, that the cross-hair of the instrument cuts the rod exactly at the bottom: of the black (tenth) figure 6. Thus the reading would befi-ve'feet and fivetenths, always reading at the top'of the figure.

If it were at the top of (tenth) figure 6, it would read five feet six-tenths. If at the bottom of figure 4, it would read five feet three-tenths. It at 0, Fig.1 of the drawings, it would read five feetsixflenths and three-hundredths. If

Each one of the black and white bars.

at d,it would read five feet 'sia tenths and sixhundredths. The arrow-head between 0 and 01 would indicate five feet six-tenths and fivehundredths. The center of the red figure 6 gives five feet and nine-tenths, and the top of this figure gives exactly six feet. In this manner the scale or graduate marks can be quickly read off by the engineer looking through the instrument, the rodrnans duty being simply to plant the rod wherever directed.

In constructing my leveling rod I prefer to observe the following proportions, although I do not confine myself strictly thereto: the width of the rod at its bottom two inches, at the center two inches and one-quarter, and at the top oneinch and three-quarters. Thethickness will be one inch at the bottom, one and one-quarter inch at the middle, and seveneighths of an inch at the top. Such a rod not only serves for leveling, but it is useful for cross-sectioning and measuring both by roddistances and stadia.

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

1. The graduated let eling-rod formed ofone piece, having one straight edge, one flat graduated face, a swelled edge, and a swelled back, for the purpose described.

2. A leveling-rod to be used upright, having graduated marks transversely across its face, indicating feet and tenths of a foot, the feet being designated by figures two-tenths ot' a foot in length, and the even tenths by figures only one-tenth of afoot in lengtl1,the long and short bars of different colors indicating hundredths of a foot, and arrow-heads applied to the longest bars indicating the exact center of each tenth of a foot, the whole being 'arranged as shown and described.

3. Aleveling-rod having a beveled straight edge, a, the graduating-marks extended only to the inner angleof the said bevel,the swelled back, and swelled right-hand edge, substan tially as described.

In testimony that I claim the foregoing as my own I affix my signature in presence of two witnesses.

THOMAS MOORE JACKSON.

lVitnesses:

JOHN J. MOMANAWAY, P. M. ROBINSON.

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