Improvements in or relating to Pantagraphs and Instruments for use in Drawing Perspective Views.
Year: 1892

page_text: Date of Application, 21st June, 1892
Complete Specification Left, 21st Mar., 1893-Accepted, 20th May,
1893
PROVISIONAL SPECIFICATION.
Improvements in or relating to Pantagraphs and Instruments for
use in Drawing Perspective Views.
I, MARTIN STÜHLER of Akademierstrasse 11, Munich in the Empire of
Germany, Artist do hereby declare the nature of this invention to be as follows:-
This invention consists principally in an instrument by which a drawing may be
made of any natural object in any desired proportion or scale, but parts of the
invention are applicable to pantagraphs in general.
The instrument depends upon the principle that if from a point in space lines are
supposed to be drawn to all points of an object, the points of intersection of such
lines and a plane cutting them at right angles to the centre line of view will give a
representation of such points on the plane in perspective. The object of this
invention is to adapt this known principle in a useful machine by reproducing these
supposed points of intersection on a plane which will not interfere with the vision,
by means of a pantagraph.
To a suitable drawing board is attached an arm or straight bar on which slides
another arm having a set screw for its adjustment. A third arm at right angles to
the second arm and parallel with the first arm crosses the second and is connected
thereto by a clamp with set screws. These arms form an adjustable open frame
which corresponds to the intersection plane beforementioned. On the first or main
arm is also a bracket with various adjustments carrying at its end an eye piece
which may be provided with a lens if desired. The adjustments enable this eye
piece to be set at a suitable point in front of the said open frame and at a distance
therefrom; the eye piece represents the aforesaid point in space. On looking at
the object to be drawn through the eye piece the position of the object or of the
board, of the frame and its side arms and of the eye piece itself may be adjusted
until the desired view of 'the object appears to be conveniently seen within the
limits of the frame which correspond with the limits or margins of the drawing to
be made.
Any suitable pantagraph may be used provided that the tracing point is
replaced by a visual point such as the intersection of two crossed hairs, or the,
point of a triangle, which may be moved over all the plane represented by the
frame, while the tracing pencil moves in a corresponding manner over the paper.
suitably placed on the board.
A suitable arm
A convenient pantagraph may however be made as follows.
carries a button or device with spring clips around which an elastic band may be
passed or on which two elastic threads may be fixed at their ends. This device is
adjustably fixed at a point outside the frame beforementioned but in the same plane
as the frame or near the plane thereof. The band passes around a similar button
carrying in its centre the pencil, or the other ends of the two elastic threads are
similarly fastened to the said pencil button. In either case therefore the loose
pencil button remains attached to the fixed button by the two parallel elastic threads
so that if the pencil is passed over any part of the paper on the board the elastic
bands cross the open frame. On the two bands is fixed a small frame carrying the
crossed hairs or visual point, it is obvious therefore that whatever figure is traced
by the pencil the same figure on a reduced scale is described by the visual point.
If on looking through the eye piece, the pencil is moved by hand so that the visual
point traces the outlines of the object viewed, then the lines traced on the paper by
the pencil will be an enlarged representation of the figure traced by the visual point
and will therefore be a perspective view of the object.

page_text: The pantagraph may be simplified by employing only one elastic thread, the
visual point might then be a glass bead strung thereon.
The pantagraph may also be made to depend upon the principle that when an
inextensible thread is wound upon two wheels of different diaineters but moving at
the same angular rate of speed the amount of thread wound on each is directly
proportional to their radii or diameters.
A thread is looped round a free roller of small diameter carrying the pencil, the
ends of the thread are carried back parallel to one another over a suitable guide and
are then wound the one on a smaller wheel the other on a larger wheel, both on the
same axle. On one of the threads is a bead to act as a visual point. As the pencil
is moved the bead follows but with a reduced movement proportioned to the relative
diameter of the wheels which are presumed to wind up all excess of thread. If the
proportion of linear movement between the bead and pencil be as a to b, the
diameter of the two wheels must be as a to 2 (b − a).
Dated this 20th day of June 1892.
HERBERT & CO.,
Agents to Applicant.
COMPLETE SPECIFICATION.
Improvements in or relating to Pantagraphs and Instruments for
use in Drawing Perspective Views.
I MARTIN STÜHLER of Akademierstrasse 11. Munich in the Empire of
Germany, Artist 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 consists principally in an instrument by which a drawing may be
made of any natural object in any desired proportion or scale, but parts of the
invention are applicable to pantagraphs in general.
Reference being made to the annexed drawings; the instrument depends upon
the principle that if from a point in space such as A Fig. 1, lines AS are supposed
to be drawn to all points of an object, the points of intersection of such lines and a
plane a cutting them at right angles to the centre line of view will give a repre-
sentation of such points on the plane in perspective.
The object of this invention is to adapt this known principle in a useful machine
by reproducing these supposed points of intersection upon a laterally placed
drawing surface by means of a pantagraph so as not to interfere with the vision.
Fig. 2 illustrates the instrument by which this is effected. Fig. 3 is a detail
view thereof without drawing board but with a different pantagraph on a larger
scale.
Fig. 3A 4. 5 and 6 are detail views of parts.
Fig. 7 is a plan view showing more particularly the holder for the eye piece.
Fig. 8 illustrates in detail a construction of pantagraph. Fig. 9 is a detail view
of its "fixed point. Fig. 10 is another view thereof partly in section.
Fig. 11 a detail view of the tracing point.
Fig. 12 a detail view of a modified form of the visual point which is to be alligned
between the eye of the draughtsman and the point of the object to be transferred
by the tracing point to its relative place on the paper.
Figs. 13 and 14 are side views of the form of "visual point" illustrated in
Fig. 8.
Fig. 15 is a diagrammatic view of another construction of pantagraph. Fig. 16
is a constructional view thereof.
Fig. 17 is a cross section of the wheel of this pantagraph.
Fig. 18 is a modification in detail of the diagram Fig. 15, and
Fig. 19 is a sectional detail view of a part of Fig. 3.
To a suitable drawing board a is attached by suitable clamps shown in Fig. 4.

page_text: a square socket ¹ in which is fixed by set screw ³ the arm c¹ of a straight bar c on
which slides sockets c² carrying each another arm d and having set screws c¹ for
their adjustment. A fourth arm d at right angles to these two last mentioned arms
and parallel with the first arm c crosses the other arms d and is connected thereto
by blocks each with two set screws d'. These arms form an adjustable open frame
which corresponds to the intersection plane beforementioned. On the first or main
arm is also a bracket with various adjustments, carrying at its end an eyepiece f
which may be provided with a lens f if desired.
The adjustments enable this eye-piece to be set at a suitable point in front of
the said open frame and at a distance therefrom, the eye piece represents the
aforesaid point A in space. On looking at the object to be drawn through the.
eyepiece the position of the object or of the board, of the frame and its side arms
and of the eyepiece itself may be adjusted until the desired view of the object
appears to be conveniently seen within the limits of the frame ed dd which corre-
spond with the limits or margins of the drawing to be made.
The eye piece or plate (Figs. 3 and 7) is provided with a socket f¹ for the
lens and is universally jointed by pin f³ in its socket and set screws f³ and e².
to the rod e sliding in sleeve e¹ and fixed by nut e³. The sleeve e' revolves on a
circular plate 92 and inay be secured at any angle thereon by a set screw g¹, and
this plate 92 is mounted on a ring i which surrounds the rod c, and carries a bracket ¹
to which is hinged a connecting rod passing to the other side of the rod c and
there connected to a slide / moving on rod and fixed by set screw 12. The rod
is fixed in the core within the square rod c. Other means may however be used
for adjusting the eye piece.
Any suitable pantagraph may be used provided that the point which is used to
follow the line of the original is replaced by a visual point such as the intersection
of two crossed hairs or the point of a triangle, which may be moved over all the
plane represented by the frame, while the tracing pencil moves in a corresponding
manner over the paper suitably placed on the board.
A convenient pantagraph may however be made as follows (see Fig. 8). A
suitable arm u carries in the fork 1 of a slide ta cylinder or device 2 revolvably
held between points 3. 3. and provided with spring clips 5 each with an eye 6 for
holding an elastic band, or two elastic threads fixed at their ends. The springs
are forced down by ring 4 (Figs. 9 and 10). This device is adjustably fixed at a
point outside the frame beforementioned but in the same plane as the frame or near
the plane thereof. The elastic band passes around a similar device 7 carrying in
its centre the pencil, or the other ends of the two elastic threads are similarly
fastened by eyes 9 in springs 8 and by ring 10 to the said pencil holder. In either
case therefore the loose pencil holder remains attached to the stationary button by
the two parallel elastic threads so that if the pencil is passed over any part of the
paper on the board, the elastic bands cross the open frame. On the two bands is
fixed by clips 15 a small frame 14 carrying the crossed hairs 11 or visual point, it
is obvious therefore that whatever figure is traced by the pencil the same figure on
a reduced scale is described by the visual point. If on looking through the
eyepiece, the pencil is moved by hand so that the visual point traces the outlines
of the object viewed, then the lines traced on the paper by the pencil will be an
enlarged representation of the figure traced by the visual point and will therefore
be a perspective view of the object.
Other means may be employed for fixing the elastic threads or band. The visual
point may also be constituted by the angular point 12, Fig. 12.
The pantagraph may be simplified by employing only one elastic thread, fastened
by set screw S¹ as shown in Figs. 3 and 19 the visual point might then be a glass
bead strung thereon.
The pantagraph may also be made to depend upon the principle, illustrated in
Fig. 15, that when an inextensible thread is wound upon two wheels R R¹ of
lifferent diameters but moving at the same angular rate of speed, the amounts of
hread F F¹ wound on each is directly proportional to their radii or diameters.

page_text: A thread is looped round a free roller N (Fig. 15) of small diameter carrying
the pencil, the ends of the thread are carried back parallel to one another over a
suitable guide M and are then wound the one F on a smaller wheel R, the other F¹
on a larger wheel R' both on the same axle a and moving together. On one of the
threads is a bead T to act as a visual point. As the pencil is moved the bead
follows but with a reduced movement proportioned to the relative diameter of the
wheels which are presumed to wind up all excess of thread, for which purpose they
may be provided with a spring. If the proportion of linear movement between the
bead and pencil be as a to b the diameter of the two wheels must be as a to 2
This device is shown in Fig. 16 in which the wheels 19 and 19 are mounted on a
square shaft 18 in a casing 16 adjustable on the arm u, the rollers
V
guide the thread. V is the visual point. Similar polygons may be used instead of
circular wheels as in Fig. 18.
-1.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed I declare that what I
claim is,
1. The combination with a drawing board of a framework of rods adapted to be
adjusted to enclose a space in the same plane as the board but without the limits of
the latter, an eyepiece mounted for adjustment with regard to said framework of
rods and a pantagraph with adjustable fixed centre, visual point traversing the
space euclosed by the rods, and tracing point adapted to transfer the same in
relative proportion to the board substantially as described.
2. A pantagraph consisting of a bracket arm u with slide thereon, a rotary button
or device therein with spring clips, a tracing point similarly provided, two parallel
elastic threads connecting the two buttons and a frame with visual point fixed on
said parallel threads substantially as described.
3. A pantagraph consisting of two wheels or similar polygons moving with same
amount of angular movement but of different diameters, a thread doubled about
the tracing point and wound severally with its ends one on each wheel or polygon
and a visual point on said thread substantially as and for the purpose described.
Dated this 21st day of March 1893.
HERBERT & Co.,
18, Buckingham Street, Strand, London, W.C., Agents to Applicant.