US335647A

US335647A - Sun-dial

Info

Publication number: US335647A
Authority: US
Publication date: 1886-02-09
Anticipated expiration: 1903-02-09

Description

(No Model.)

B. L. SPENCER.

SUN DIAL.

Patented Feb. 9, 1886.

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Srrns RALPH L. SPENCER, OF HARTFORD, ASSIGNOB OF ONE-HALF TC HERMAN O. ROSE, OF ESSEX, CONNECTICUT.

SUN-DIAL.

EPJEZCIPICATION forming part of Letters Patent No. 335,647, dated February 9, 18186,

Application filed June 16,1884. Serial No. 134,964.

To all whom it may concern:

Be it known that l, RALPH L. SPENCER, of Hartford, in the county of Hartford and State of Connecticut, have invented certain new and 5 useful Improvements in Sun-Dialsfof which the following is a description, reference being had to the accompanying drawings and the letters of reference marked thereon, where,

Figure 1 is a front View of my improved 1o dial. Fig. 2 is a view in central section of same, on plane denoted by line w of Fig. 1. Fig. 3 is a detail view showing the dial-card and pinion-bearing stein as removed from the case. 1 My invention relates more particularly to the class of sun-dials that are made in a form for convenience in carrying about the person;

and it consists in the improved combination of the case and dial whereby the latter is adjustable.

In the accompanying drawings, the letter (t denotes a case, preferably of sheet metal, of about the usual shape and dimension of a watch-case; b, a hollow stem fast to or intogral with the rim of the case; a, a rotary shaft fitted within the stem, bearing on its outer end a milled head, 0', and on its inner end a pinion, c"; d, the dial-card, having upon its lower side an annular rack with teeth arranged to mesh with the teeth of the pinion in such manner that by turning the shaft, as by means of the milled head, the card will be rotated within the case. This card has a central and circular perforation in its face large enough to expose to View a magnetic needle, e, pivotally supported on a pin fast to the case at about its center in such manner that the needle turns freely in the ordinary manner. This card bears printed or stamped upon its face and next to the opening the cardinal points, and on each side of either the north or the south point the circle is divided in degrees to about fifteen degrees upon each side, and these divided arcs, used for finding the true merid- 4 5 ian, are what I call correction-arcs. In the annular space next outside of these points of the compass are arranged the time-lines f, as on the ordinary sun-dial, and outside of the timespaces is arranged a series of numbers, from one to thirty-one, (denoted by f The glass is preferably secured below the (N0 model.)

card, so as to prevent the compass-needle from becoming displaced, and the case may be provided with a cover attached with a hinge, as

in the manner common in hunting case watches.

Spanning the circular opening in the card, and in line with the meridian-line of the compass-card, is pivoted a gnomon, 9, so attached to the card that it may be held in a. vertical 6O plane for the purpose of throwing a shadow, or folded down for convenience in closing the case.

In using this device the case is held in the hand in a horizontal plane, so that the needle 6 will traverse, and by means of the shaft 0 the dial may be turned until the meridian-line coincides with the direction of the needle, the gnomon being raised to a vertical plane, so as to properly cast its shadow upon the timecard. This would give the correct reading if the magnetic meridian of a place coincided with the true meridian; but owing to the variation of the needle some allowance must be made, and the graduated arcs upon each side 7 5 of the meridian of the compasscard are used to measure this variation and to adjust the plane of the gnomon in the meridian of the place where the observation is made by setting the time-card so that the needle shall point to the proper degree, according to the magnetic variation. For example, if the magnetic variation at the place where the observa tion is made is nine degrees west, the dialcard, and with it, of course, the gnom'on,should 8 be adjusted so that the north point of the needle shall point nine degrees west of the north point on the time-card, when the gnomon will lie in the plane of the true meridian, and the time can be more accurately detero mined by the position of its shadow. Fast to the edge of the outer case,and pointing inward, is arranged an index-hand, a, which, by turn ing the dial-card bearing the calendar f, may be made to point to the day of the month, and 9 5 by means already described the device may be made to serve as a magnetic compass, a sun-dial, and a calendar, all compactly and conveniently united in the one instrument.

I claim as my improvement- 1. The combination of a case, a, bearing a rotary stem terminating in a pinion within the ease and a handle without, a dial-card having annular gear in mesh with the pinion and bearing an adjustable gnomon, and a magnetic needle arranged within the case, all substantially as described.

2. The combination,with a case hearing a rotary stem terminating in a pinion within the ease and a handle without, of a dial-card having an annular gear in mesh with the pinion and bearing an adjustable gnomon, substantially as described. I

3. As an improved article of manufacture, the herein-described combined compass and sun-dial, eomprisingthe case a, a magnetic needle pivoted centrally therein, a dial-card 15 provided with the annular gear, the handled pinion meshing with the annular gear and adapted to rotate the same, the adjustable gnomon, and marks and figures upon the several parts, substantially as shown, and for 20 the purposes described.

RALPH L. SPENCER.