US281267A - Artificer s leveling-instrument - Google Patents

Description

2 Sheets-Sheet 1.

(No Model.)

J. W. HARMON;

ARTIFIGERS LEVEL'ING INSTRUMENT.

No. 281,267. Patented July 17,1883;

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(No Model.) I ZShets-Sheet 2.

v J. W. HA'RMON.

ARTIFIGBRS LEVELING INSTRUMENT. No. 281,267. Patented Jul lv, 1883 N. PETERS Phubuihogmpher. Wzuhmglan. D. c

Unrrnn STATES PATENT Orrrcn.

JOHN TV. HARMON, OF BOSTON, MASSACHUSETTS.

ARTIFlC ERS LEVELlNG-INSTRUMENT.

SPECIFICATION forming part of Letters Patent No. 281,267, dated July 17, 1583. Application filed January 29, 1853. (No model.)

To all whom it may concern:

Be it known that I, JonN W'ARREN HAR- MON, of Boston, in the county of Suffolk, of the Commonwealth 01" Massachusetts, have in vented a new and useful Improvement in Artificers Leveling -Instruments; and I do hereby declare the same to be described in the following specification and represented in the accompanying drawings, of which Figure 1 is a top view, Fig. 2 a front elevation, and Fig. 3 a transverse and median section, of an instrument provi tied with my invention, the nature of which is defined in the claim hereinafter presented.

This instrument has a telescope, A, and an arched supporting-bar, B, to which such telescope, at its middle, is pivoted, there being in the said bar horizontal and vertical spirit levels Cand I). It also has screws E E for adjusting the axis of the telescope in parallelism with that of the horizontal spiritlevel. The bar B, at the center of its lower edge, is pivoted to a divided limb, G, at the center thereof, and such limb is furnished with-three adjusting-screws, H, which screw into cars or projections a, extending from thelimb at equal distances apart. Each of the said screws has a tapering pivot, b, to enter and automatically fit closely one of three steps, 0 c c, projecting upward from the head I of a tripod. The head I has three leg-supporting flanges, (1, extending downward from it, each entering between the two prongs of one of three legs, K, furcated in its upper part, as represented. There is to each leg ascrew-bolt, c, which goes through its prongsf f and the flange (I be tween them, and has screwed upon it a nut, g. By such means each leg may be clamped to its sustainingflange with the necessary power to cause the leg to move on the bolt with the necessary friction to keep steady the leg and tripod-head while the instrument may be in use. Furthermore, the divided limb has each of its areal divisional marks arranged not ra dially, bar B when such side is against the saidmark. This enables the side of the bar, instead of its axis, to be used with the divisions of thelimb, and taking or setting of angles with the instrument. From the divided limb there project upward, on opposite sides of the telescope, two posts, L L, on the upper ends of which there is secured a st tionary magnetic compasssupport-er, it consisting in a cylindrical box,

M, open at top, and having within and to fit it a magnetic compass, N, whose needle is shown at h. This compass can be revolved by hand within its supporter; and there is fixed to and extended from the telescope and over.

the compass, as shown, an index-pointer, 'i, it being adapted so as to be adjustable vertically. By means of the said pointer and the divided limb or ring is and needle of the compass, either angles or courses may be determined by the telescope, as will be easily understood by persons acquainted with leveling-instruments, theodolites, or surveying-compasses.

Fig.- 4 is a side view of the tripod and the limb G. Fig. 5 is a top view of the head of the tripod. Through the tripod-head, at its center, is a circular opening or hole, 0, to enable a plumb-line, when attached to the divided limb at its center, to hang freely and vertically, in order to centralize the instrument over and relatively to an object, as occasion may require.

1 claim- The combination of the stationary magnetic compass supporting box and the magnetic compass provided with the needle and divided limb, as set forth, with the telescope and the index-pointer applied thereto, all being adapted and arranged substantially and to opcrate as represented.

J OHN WARREN HARMON.

W'itnesses:

R. H. EDDY, E. B. PRATT.

but so as to line with one side of the 5

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