Improvements in Planetariums.
Year: 1897

page_text: Date of Application, 7th Sept., 1897-Accepted, 6th Nov., 1897
COMPLETE SPECIFICATION.
Improvements in Planetariums.
I, JAMES MCWADE, of 223 East 29th Street, in the City, County and State of
New York, United States of America, Mechanic, do hereby declare the nature of
this invention, and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
-
This invention relates to devices for illustrating the relative positions and
movements of the heavenly bodies, and the object is to provide a simple device
of a mechanical character, for illustrating the relative movements of the sun,
earth and moon about their axes, and the orbital movements as well, in con-
nection with a stellar chart showing the stars of both the northern and southern
hemispheres, or the principal stars thereof. This chart is so arranged that, by a
mechanical shift, the stars of either hemisphere may be made to appear signifi-
cantly, at will, to correspond with the position of the earth in its orbit. This
shift or transformation may be effected by rendering one set of stars transparent
while the others are opaque, or the sets of stars may be made distinguishable by
contrasting colors, or by one set being made to appear black and the other white;
and these distinctions may be effected by transmitting light through star-apertures
in the chart or by reflected light, all as will be hereinafter more particularly
explained.
The invention will be more minutely described with reference to the accompany-
ing drawings which illustrate an embodiment of the same.
Figure 1 is a plan view of the apparatus on a comparatively small scale, the
diameter of the sun being preferably about 7 or 8 inches in the actual apparatus.
Figure 2 is a side elevation thereof.
Figure 3 is a dissected view of the base of the apparatus bearing the stellar
chart, illustrating the construction for producing the star transformation or shift.
Figure 4 is a transverse section of the base on line in Figs. 1 and 3.
The remaining figures are drawn to a larger scale and illustrate the mechanism
for producing the movements of the sun, earth and moon.
Figure 5 is a side elevation of the mechanism;
Figure 6 is a plan, and
Figure 7 is a plan showing the mechanism below the line ' in Fig. 5.
Figure 8 is a transverse section on line 8 in Fig. 5.
I will first describe the base, A, which bears the stellar chart or map, premising
that this chart is adapted to show, by shifting or transformation, on a circular
field, the stars, or the principal stars, of both the northern and southern
hemispheres.
Referring to Figs. 1, 3 and 4, the base A comprises a square frame in which is
a circular stellar chart, a, on which are marked the principal stars of both hemi-
spheres, here indicated merely by a few circular apertures, s³, supposed to
represent the stars of the northern hemispheres and other apertures, &, supposed to
represent those of the southern hemisphere. In order that the stars of one hemi-
sphere only may be indicated at one time say by transmitted light-the
n

page_text: construction illustrated in Figs. 3 and 4 is employed. Under the chart a (broken
away in Fig. 3) is rotatively mounted a circular disk, b, having in it two sets of
apertures, and c³, so placed that by rocking the disk about its center, c, the
set of apertures c may be brought into register with the apertures in the
chart a, or the apertures c³ into register with the apertures, in the chart. When
either set of stellar apertures al or s³, is brought thus into register with those of
the disk b, the light will pass through thereat and produce bright points of light,
simulating stars, while those of the other set remain opaque.
The disk may be
rocked or shifted by any convenient means; as shown in Fig. 3 the disk has, at
one side a lug, b', which has a limited play in a recess formed in the distancing
piece, or sheet of pasteboard of the base A. Operating tabs, 2 and 3, are
connected by cords or tapes with the respective sides of the disk. By drawing on
the tab, for example, the disk is rocked or rotated in one direction, and by draw-
ing on the tab 3, it is rotated in the opposite direction. The movement in each
direction is so limited by the lug 6 that at each terminus of the same one set
of stellar apertures in the chart u will be put in register with the corresponding
set of apertures in the disk b. If it be desired to transmit colored light at the
stellar apertures, it is only necessary to cover the face of the disc b with a piece
of thin, translucent material, as tissue paper, of any desired tint or color. If
light is to be transmitted as bright points, to represent the stars, very small holes,
as pin-holes, will suffice.
In order to designate which set of stars is displayed on the chart, the device
illustrated in Figs. 1 and 3 may be employed. On a hinged strip, c³, are inscribed
the words "Southern Celestial Hemisphere" and
66 Northern Celestial Hemi-
sphere," and the free end of this strip is coupled to the tab 62, so that when this
tab is drawn upon the inscription "Southern Celestial Hemisphere" will appear
at a sight opening, a³, in the frame about the chart a. When the tab 63 is pulled
or drawn upon, the other inscription will appear at the sight opening.
Around the margins of the chart a are marked the graduations representing
the degrees of the circle, the twelve monthly divisions, and the names of the four
seasons. These are clearly shown in Fig. 1, although I have not deemed it
necessary therein to extend the graduations entirely around the circle.
I will now describe the mechanism for illustrating the movements of the sun,
earth and moon, as illustrated in Figs. 1, 2, 5, 6, 7 and 8.
This mechanism is designated as a whole in Figs. 1 and 2 by B. S represents
the sun, E the earth and M the moon. At the back of the base A is fixed a bar
or plate, 1, that has on it a tubular bearing, 2, which extends up through the center
of the chart a. The disk turns about this bearing piece. Mounted on the
plate 1, at its back, is a frame, 3, in which is mounted a spindle, 4, which extends
upward through the bearing 2, and rotates therein. On the upper end of this
is fixed a head, 5, on which is mounted a cradle, 6. This cradle is adapted to
slide endwise, to-and-fro, in bearings on the head, and to guide the cradle in its
movement a longitudinal central rod, 6, on the cradle plays through apertured
lugs, 5, on the head. The cradle has also two racks, 6, at its base, which play
in guides, 5b, on the head 5.
On the spindle 4, in the frame 3, is fixed a toothed wheel, 7, which gears with
a toothed wheel, 8, fixed on the driving arbor, 9, this latter being squared, as here
shown, to receive a key. The wheel 7, is connected, through a train of gears, 10,
with a toothed wheel, 11, fixed on a tubular or hollow spindle, 12, embracing the
spindle 4, and extending up to the head 5 thereon. The effect of the train 10 is
to cause the spindles 4 and 12 to rotate in opposite directions when the arbor 9
is rotated. On the upper end of the hollow spindle 12 is fixed, directly beneath
the head 5, a toothed wheel 13, and with it gears a wheel, 14, fixed on an upright
arbor, 15, in the head. This arbor 15 carries on its upper end a toothed wheel, 16,
which gears with a pinion, 17, on the same upright arbor with a crown wheel, 18,
which latter gears with a pinion, 19, on the same horizontal arbor with a toothed
wheel, 20; the wheel 20 gears with a long pinion, 21, which has bearings at its

page_text: ends in the ends of the cradle 6. The arbor or spindle, 22, on which the earth E
is fixed, is secured in one end of the long pinion 21 and rotates therewith.
The effect of rotating the operating arbor 9 is to rotate the head 5 and cradle G
about the spindle 4 as an axis, and to rotate the hollow spindle 12 and wheel 13
in the opposite direction. The wheel 13 drives the wheel 14, and through it, and
the wheels 16, 17, 18, 19 and 20, it drives the long pinion 21, thus imparting the
proper axial rotation of the earth E.
The moon M is carried by a tubular spindle, 23, on the spindle 22, and is driven
from the latter at the proper speed through the medium of toothed wheels 24 and
25 on the respective spindles 22 and 23, and suitable connecting gears, 26, on the
end of the cradle 6. Thus the orbital motion is imparted to the moon.
The sun,
is mounted on an upright spindle, 27, mounted in a bearing on the
end of the cradle 6 opposite to that where the earth is mounted, and it has the
proper axial rotation imparted to it by a wheel, 28, on the spindle 27, which gears
with and is driven by a toothed wheel, 29, on the end of the long pinion 21.
The above described mechanism imparts the proper axial rotation to the sun and
earth, the proper orbital movement to the moon about the earth, and a circular
orbital movement to the earth and moon about the sun; it now remains to explain
the means employed for imparting the elliptical orbital motion to the earth.
Fixed indirectly to the tubular spindle 12, in the plane of the two racks 6b on
the cradle 6, and between the latter is a mutilated gear wheel, 30, having teeth
on but one-half of its periphery. These teeth gear, alternately, with the racks 6b,
and consequently, continuous rotation of the wheel 30 in one direction imparts
a reciprocating, to-and-fro motion to the cradle 6 in its guides. This motion,
combined with the rotary motion of the cradle about the spindle 4 as a center,
produces the proper elliptical movement of the earth in its orbit. As shown
in Fig. 8, the wheel 30, is secured by a set-screw to the sleeve-like boss of the
wheel 13, which latter is fixed to the spindle 12, but this is only a feature of con-
struction and does not relate to the invention.
The sun S may be fixed on its upright spindle, if desired. However, I prefer
to mount it frictionally thereon so that it can be moved or adjusted up or down on
the spindle 27, as desired in order to illustrate better the varying angles of the
earth's axis with the plane passing through the earth and sun. As shown in Fig. 2,
friction nuts, 31, of some soft material, are placed on the spindle 27 above and
below the sun S, to hold it in place, but any suitable frictional device may be
employed as well. In Figs. 1 and 2 the cradle 6 is represented as covered by an
enclosing cap, 32, to hide the mechanism and prevent it from distracting the
attention of the pupil. This, however, is not essential, nor is it necessary to
enclose the mechanism in the frame 3, as indicated in Fig. 2. The bar or plate 1
is only a convenient means of connecting the gearing of the panetarium to the
base A and it may be of any form or construction, and of any material.
I have called the spheres S, E and M, the sun, earth and moon, respectively, for
convenience of description; they merely simulate these bodies, of course, as in
any planetarium. They may be of any suitable material and may have
geographical markings if desired; but this is not essential to my invention.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is:-
1. The combination with a base having on it a stellar chart, and having
mechanical means for displaying the stars of either hemisphere at will, of a plane-
tarium mounted on said base concentric with the stellar chart and adapted to
show the movements of the sun, earth, and moon, substantially as set forth.
2. A base for a planetarium comprising a stationary stellar chart having stars
of both hemispheres marked on it by apertures, a rotating disk behind said chart
and adapted for partial rotation, means for limiting such rotation, and means for
effecting such rotation, said disk having also the stars of the different hemispheres

page_text: marked thereon and adapted to be brought into register with the star-apertures in
the chart, substantially as set forth.
3. In the base A of the planetarium, the combination with the fixed stellar
chart a, having in it two sets of apertures s¹ and 3, representing respectively the
stars of the two hemispheres, of the rotatable disk b, back of said chart, said disk
having in it two sets of apertures c¹ and c³, adapted to be brought, respectively,
into register with the sets of apertures s¹ and by the rotatory movement of the
disk, means for limiting the extent of rotation of said disk, and means for rotating
said disk, substantially as set forth.
4. In the base A of the planetarium, the combination with the fixed stellar
chart a, having in it two sets of apertures s¹ and s², representing respectively the
stars of the two hemispheres, of the rotatable disk b, back of said chart, said
disk having in it two sets of apertures c¹ and c, adapted to be brought, respectively,
into register with the sets of apertures and by the rotatory movement of the
disk, means for limiting the extent of rotation of said disk, tabs 63 and 6³, connected
to opposite sides of said disk for operating the same, and a hinged strip c³, bearing
inscriptions, arranged behind a sight-opening in the face of the base A, and con-
nected with one of the said tabs, whereby said hinged strip is operated when the
disk b is shifted, substantially as set forth.
5. In a planetarium, the combination with an upright spindle 4, carrying a
head 5, the said head, and a cradle 6 mounted for reciprocating movement on
said head transversely to the axis of the spindle 4, of the tubular spindle 12, a
train of gears connecting the spindles 4 and 12, whereby they are rotated simul-
taneously in opposite directions, the long pinion 21, in the cradle, a gearing train
between the spindle 12 and said pinion, whereby the pinion is rotated therefrom
as the head turns, racks 6b on the cradle, a mutilated gear wheel 30 on the shaft 12
adapted to engage said racks alternately and thus impart a reciprocating movement
to the cradle, a sphere E, carried by the pinion 21, and representing the earth,
the tubular spindle 23, on the spindle carrying the earth, gearing between the
pinion 21 and spindle 23 whereby the former drives the latter, a sphere M, carried
by the spindle 23 and representing the moon, an upright spindle 27, on the cradle,
gearing between the pinion 21 and said spindle, whereby the former drives the
latter, and a sphere Ŝ on said spindle 27, representing the sun, substantially as
set forth.
6. In a planetarium, the combination with the cradle 6, and mechanism for
imparting thereto a rotary movement and a reciprocating movement at right-
angles to the plane of said rotary movement, of the spheres representing the earth
and moon carried by said cradle, mechanism for imparting the proper rotatory
and orbital movements to said spheres, the upright spindle 27, mechanism for
rotating the same, and the sphere S, representing the sun, mounted adjustably
on said spindle 27, so that it may be shifted up or down thereon at will, sub-
stantially as set forth.
Dd his fith day of Santamhom 1807
STEPHEN WATKINS,
Wolverhampton. Agent for the Applicant.