US1676912A - Device for calculating time - Google Patents

Description

July 10, 1928. 1,676,912

- F. C. MEACHAM DEVICE FOR CALCULATING TIME Filed Nov. 15, 1925 fizz/0M4 Madam avwewtoz 32x 1; Qua/nude Patented July 10, 1928.

EEEEEEIoK c. MEACHAM, 0E GARDEN GITYyNEW YORK.

DEVICE FOR CALCULATING TIME.

' Application filed. November 13, 1925.- Serial no, 68,815.

My invention relates to a device foruse in,

the calculation of time by means ofthe position of certain stars; this is accomplished by reading, on my device, the'relative position of the stars, followed by certain calculations, as will be hereinafter fully set forth. The object of my invention is to enablethe quick andeasy determination of such relative position with a reasonable degree ofac- 'curacy under the conditions in which the device 1s ordinarily used; another object of.

my invention is to provide a device forsuch purpose which shall be compact and reasonably simple and. cheap to manufacture in g tended) meets device. I, v

In the drawing, 21 represents-a disk which may be of transparent material, such as celluloid'. The. disk is preferably divided into four equal sectors by the perpendicular diameters 25., 26. The periphery of the disk is also divided into twelve equal spaces by the diameters and the lines indicated at 22 or by other suitable means for indicating the divisions of the disk; these spaces are again preferably divided, as by the lines 23, 24, in-

to four equal parts. The lines 22, as well as the outer extremities of the two diameters, may be numbered, as indicated at 27, in the same manner as the dial of a clock, from 1 to 12 inclusive. At the outer end of one diameter, adjacent the numeral 12, I prefer to place an outwardly-pointing arrow-head, or other easily noticeable mark 28, to indicate clearly the uppermost point of the disk. 7

V In my preferred form, a central aperture is stamped out of the material'of the disk and a small metal eyelet 29 inserted therein. Carried by the eyelet 29 is an arm 3O which may be transparent. The arm, when extended, projects beyond the outer edge of the disk. The eyelet is riveted over a portion of the arm to hold it in rotatable. relation to the disk. The eyelet 29 is preferably a true eye'- let-i. e., of such character that it will not obstruct clear vision through the aperture at the center of the disk.The'arm 30.has preferably a length about equal to the diam eter of the disk and it may be slotted 1 throughout approximately halfof its length, as indicated at 31, so that, when the'deviceis notin use, the arm may slide along theeyelet over the faceof the disk into position where it does not project beyond the edge of the disk. It will be understood that this 7 is merely for compactness and convenience in carrying. The longitudinal center ofthe arm isdelined, as by the line 32, which preferably extends from the outerend of the arm to apomtwhich (when the arm is fully X- or crosses: the edge of the disk. It will of course be understood that any other suitable means may be used to define, by means of the arm, airadial line; for example, the outer end of the arm may be offset so that one edge thereof lies along' a radius (extended) of thedis'k.

I will nowdescribe one method of using my dev ce; this method enables a surprisingly accurate calculation. of time, at least when'used at or near aline of longitude which determines the standard time: for that when my device isu-sed locality. Of course,

atlsome distance eastlor west of such line of longitude, the calculated time will not agree so well with the standard time, but it will everywhere agree very closely with the true time or sun-time.

.In the method here described, my device is used to determine the relative position of the North Star or Polaris and the two stars in theconstellation Ursa Major known as on and ,8 or the Pointers. My device is held before the eyes of the observer-say eight inchesfrom the eyes, with the arrowhead 28 pointing upward and the diameter in a vertical plane through the me- 25 lying The presence of the two diameters ridian.

on the face of the disk'assists the observer inproperly positioning it. The diskshould.

beheld so as to lie in a plane perpendicular to the line of vision between the observer and Polaris. The arm 30 having been fully extended, the that Polaris is visible through the hole at the center of the disk-.as indicated at 33in the drawing. The arm 30 is then rotated,

without disturbing the position of the disk,

until the Pointers of the constellation Ursa Major, the line 32 or the indicated at 34, 35, lie'along line 32 if continued. This adjustmenthaving been made, the relative device is then so positioned position of the stars is read by taking vthe.

reading on the disk as determined byjthe add to that the number of months and quarter-months that have' elapsed during the calendar year in this case 7 (January to 'J uly, inclusive, being 7 and the eight days of August being approximately one quar ter); the sum then equals 8%; next, double I this-sumgivin in this case, 17 subtract this final amount from- 4O g1ving 22%; This last figure gives the time.

Wher e,as here, the time given is greater than 12, then 12 or 2st or 36, may be de; ducted so that the net result will be less tha-n 12. Proceeding thus in the example given, '12 is deducted from 223/ leaving 10% which means that thetim'e is 10 :45. I am. aware that modifications may be v made in my device by those skilled in the art and, therefore, I desire protection for all such forms of my device as come within the scope of the appended claims. 3

I claim:

1. A stellar time indicator comprising a disk having a central opening and a marginal scale, a longitudinally slotted arm adapted to be positioned to lie'wholly within 1 the margin of said disk, means associated withrsaid' central opening having an open- 'ing in alignment therewith, said slotted arm being rotatably and slidably' carried by said means and having aline'thereon which, i!-

pro ected, would intersect the center of said disk. r i. r

2. Astellar time indicator comprising a disk having a central opening and a marginal scale, a longitudinally slotted arm of transparent material"adapted-to be positioned to lie wholly. within the margin of said disk, means associated with said central opening having an opening in alignment therewith, said slotted arm being rotatably andslidably carried by said means and having a line thereon which, if'projected, would intersect the center 'of'said disk,'said disk having a diametral line thereon adapted. to be pointed toward the zenith-when 'an obs'ervation is to bemade. l

3. A'stellar time indicator comprising a disk having a' central opening and a martransparent 'material, an through said central opening and through rotatably and slida-bly carried by said eyelet and having a line thereon,'which, if pro jected, would intersect the center of said' disk, said arm having substantially the length of the diameter of said diskand the slot therein being substantially equal in length to the radius of said disk-whereby ginal scale, a longitudinally slotted arm of 3 eyelet passed 7 said arm may be positioned to lie wholly withincthe margin of said diskfsaid disk having a diametral line thereon adapted 'tobe pointed toward the zenith when an observation is to be made.

FREDERICK C. MEAOHAM.

6o the slot in said arm, said slotted arm being 1

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