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Патент USA US2094833

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Oct. 5, 1937.
Filed Dec. 31, 1956
2 Sheets-Sheet“ l
1055p” MWuuF/Z.
Oct. 5, 1937.
2,094,833 -
Filed Dec. 31, 1936
2 Sheets-Sheet 2
-_4_ _
BY 1555p” M9400”:
Patented Oct. 5, 1937
Joseph McAuliffe, Idaho Springs, Colo.
Application December 31, 1936, Serial No. 118,529
4 Claims. (Cl. 33-452)
This invention relates to a portable sun dial
and has for its principal object the provision of
a neat, compact, highly ef?cient unit which can
be used to determine the hour of the day by the
5 sun in any latitude, and which can be easily car
ried upon the person.
It is more particularly designed for use by
campers, hunters, travelers, and explorers who
might lose or damage ordinary time pieces and
10 who have no access to a clock.
It is also valu
able ior instructing classes in schools, boy scout
troops, etc., in the fundamentals of time deter~
mination and astronomy.
Other objects and advantages reside' in the
15 detail construction of the inventiomwhich is de
signed for simplicity, economy, and e?‘iciency.
These will become more apparent from the fol
lowing description.
In the following detailed description of the in
20 vention reference is had to» the accompanying
drawings which form a part hereof. Like numer
als refer to like parts in all views of the drawings
and throughout the description.
In the drawings:—
the invention.
Fig. 4 is a longitudinal section through the
form of Fig. 3, taken on the line 4—4, Fig. 3.
Fig. 5 is a detail view of the roll‘ operating
mechanism of the form of Fig. 3.
cates positions on the dial 22. The dial is in
dexe-d in all of the latitudes in which the inven- 5
tion is expected to be used. A scale running from
20° to 60° is usually all that is necessary.
A calendar is printed or engraved upon the
plate I6, as shown at 25. The calendar is printed
in two sections, with the months from July to 10;
November at one side, and the months January
'60 May at the other side, and with the two re
maining months June and December at the ex
tremities as illustrated.
The calendar is accu
rately laid out by projection from a declination 15
scale lid on the latitude plate 33. The declination
scale is indexed to a mid-leap-year declination.
The two sections of the calendar are separated
by means of a calendar slot 26. A ?exible string
27 terminating in a plumbweight 28 extends 20
through the slot 26 from a suitable head on the
back thereof. The weight 28 is slidable along the
string 2? and may carry an indicating pointer 42.
Below ~the plate Iii on the board II] is a remov
Fig. 1 is a face view of one form of the improved
portable sun dial as it would appear in use.
Fig. 2 is a side view thereof.
Fig. 3 is a face view of an alternate form of
Adjacent the slot 20 is an arcuate latitude in
dex or dial 22 which is visible through a window
23 in the plate l6. An indicating arrow 24 indi
The invention comprises a board In, of any
35 suitable material such as cardboard, wood, bake
able time chart 2.‘! which may be clamped thereon 25
by means of clamp nuts 30‘. Upon the time chart
29 are two hour circles 3| and 32, the circle 35
designating the A. M. hours, and the circle 32,
the P. M. hours. The time indications of each
hour circle are joined to those of the other by 30
means of a series of vertical guide lines 43. The
charts 29 must be changed to correspond with the
latitude of. the place where the dial is to be used.
As illustrated, a “Lat. 40” chart is shown on the
board Ill.
lite ?ber, etc. At the top of the board are two ' In use, the user turns the flaps ll and i2 to
hinged ?aps II and I2. The face of the ?ap H the vertical position as illustrated. He then sets
is provided with a narrow slot l3 and the face
of the ?ap I2 is provided with a. vertical indi
40 cating line M. The flaps H and I2 are mounted
upon suitable hinges 15 so that when not in use,
they may lie ?at against the board I0 and, when
in use, they will stand upwardly at right angles
to the surface of the board and parallel to each
45 other. The slot I3 is aligned with the line H! on
a horizontal line 4| across the board.
A latitude plate I6 is pivoted upon a suitable
pivot rivet extending through the board I 0. Ad
jacent the rivet H, the latitude plate passes
50 through an arcuate slot l8, and is secured to the
board on the rear face thereof. The plate I6
can be set at any desired angle by means of a
clamp screw i9 which passes through an arcuate
slot 20 and terminates in a clamping head 2| on
55 the rear of the board.
his latitude plate it on the dial 22 to correspond
with the chart 29 and with the place of use. As
illustrated, the plate is set“ at 40° latitude. He 40
now slides his string 2'! along the slot 26 to bring
it opposite the approximate day of the month.
He now swings the string 21 over the I2 noon
mark on the hour circles (which is directly over
the pivot point of the plate it) and slides the 45 .
Weight 28 along the string until the point of the
indicating arrow #12 indicates the exact noon
The board is now set for use.
By holding the board ill in a plane intersect
ing the sun and inclining it to the proper angle, 50
the sun’s rays will shine through the slot l3 form
ing an image on the flap l2. By tilting the board
to the right or left, this image is brought directly
upon the line 14 of the flap 12. At this time the
string 27, due to its weight 28, is hanging verti- 55
cally across the time chart 29 and the indicating ' with a ray from the sun; a movable plate on said
board; a ?exible member depending from said
arrow 42 on the weight will indicate a certain one
of the vertical guide lines 43. If it is morning
the time can be read by following this line up
ward to the A. M. hour circle SI, and ifit is after
noon, the hour is read by following the line down
ward to the P. M. hour circle 32. As illustrated
the dial is indicating either A; M. or P. M. de
pending, of course, on whether the dial is being
used in the morning or the afternoon.
By care
ful holding and accurate manufacturing, the
time can be foretold accurately in ?ve minute
Ordinarily, the device will be used in the same
latitude at all times so that the chart 29 need
not be oi‘ten changed. For travelers or explorers,
however, who are constantly changing their lati
tude, the charts must be constantly changed to
correspond thereto. An alternate form of the
20 invention to facilitate this constant change is
shown'in Figs. 3 and 4. V
In the latter form a latitude plate 33“, similar
to the plate I6, is pivoted on a side bracket clip
plateyan hour scale intersected by said ?exible
member when said board is in alignment with
said ray; a latitude scale’ upon said board; means
for aligning and setting said'plate at a desired
indication on said latitude scale; a calendar scale
‘on said plate; and means for varying the posi
tion of said flexible member with'reference to said
2. A portable sun dial comprising: a ?at board;
a pair of upstanding members parallel to each
other on said board, there being a slot in‘ one of
said members and an alignment indication on
the other of said members to align said board
with a ray from the sun; a movable plate on said
board; a flexible member'rdepending' from said
plate; an hour scale intersected by said ?exible
member. when said board is in alignment with i
said ray; 2, pair of rollers extending laterally of
said board; and a-continuous strip of flexible material reeling from one roll to the other for car
rying a series of differing hour circles.
3. A portable sun dial comprising: a ?at board;
a declination platepivoted adjacent one side edge
34, so' that it extends over the 12 noon point on
a time chart printed on the face of a relatively
of said board so as to swing over the face there
long1paper strip 35. The strip 35 contains a se
of’; a latitudescale for determining the position
ries of time charts 36, each laid out for a' par-.
ticular latitude. The latitude for which each> of the said declination plate; means forrlocking
chart is to be used is indicated by an indexsuch said plate at any desired position on said latitude
scale, said plate having a slot extending across 3O
30 as shown at 3?. The strip 35 reels and unreels
its face at right angles to a radius extending to
from a pair of rollers '38; operated from a thumb
button 39, on the side of the device. The thumb its pivot; ‘a plumb line depending from said slot
downwardly over said board; a calendar scale
button may operate the rollers directly, or it may
be connected with both rollers through suitable along said slot for determining the point of sus
gears 44 and friction discs 45, as illustrated. pension of said plumbrline; van hour scale below’ .35
This enables the user to quickly change his time said declination plate over which said plumb line
charts to correspond to the latitude of the place extends; and means for aligning said plate with a
of use. VAs each; chart is brought into position ray from thesun.
its 12 noon point mustbe brought directly be
' 4. A portable sun dial comprising: a ?at board;
40 neath the pivot point of the latitude plate. This
.a declination plate pivoted adjacent one side edge
positioning is facilitated by printing an indication
45 on the strip at each time chart to’ be aligned
with a corresponding indication 47 on the board.
of said board so as to swing over the face there
of ;V a latitude scalerfor determining the position
of the said declination plate; means for locking
While a speci?c form of the improvement has’ ' said plate at any desired position on said latitude
45 been described and illustrated herein, it. is de
sired to be understood that; the same may be
varied, within the scope of the appended claims,
without departing‘f-rom the spirit of the inven
Having thus described the invention, what is
claimed and desired secured ,by Letters Patent
1. A portable sun dial comprising: a ?at board;
a pair of upstanding members parallel to each
other on said board, there being a slot in one of
said members and an alignment'i'ndication on
the other of said membersgto; align said’ board
scale, said'plate having-a slot extending across
its face atright angles to a radius extending to
its pivot; a plumb line depending from said slot
downwardly over said board; a'calendar scale
along said slot for determining the point of sus
pension of ‘said plumb line; an hour scale below 50
said declinationv plate over’which said plumb line
extends; means for aligning said plate with a ray
from the sun; and a head .member on said plumb
line preventing the'ilatter froinpulling from said
slot, said head being clamped between said dec-.
lination plate and said flat board.
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