Ellipsograph.
Year: 1894

page_text: COMPLETE SPECIFICATION.
Ellipsograph.
We, GUSTAV HEINEL, Forester, and CARL BARTH, Foremaster, of Eisenhammer,
Cüstrin in the Province of Brandenburg, Prussia, 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 :-
The ellipsograph represented in the annexed drawing is based on the principle
that each point of a straight line moving with its terminal points on two straight
lines at right angles to each other, describes an ellipse of fixed axial magnitudes.
It is however not necessary that this straight line be terminated at both ends by
the points moving on the lines, but it may be imagined as continued beyond the
two guide-points and yet each point of the straight line and also of the continuation
describes an ellipse.
On this fact is based the apparatus represented in annexed drawing, of which we
give an elevation and ground-plan in Figs. 1 and 2, in Fig. 3 a diagram and in
Figs. 5 and 6 an elevation and ground-plan of the slide-rod, representing the
straight line guided, with pencil attached and scale engraved; Fig. 4 represents
the drawing-apparatus.
There is nothing further to be said about the theory of the apparatus drawn in
Fig. 3, after the fundamental idea mentioned at the beginning of this description;
it is immediately apparent to all who are technically educated and must be assumed
to be known.
The ellipsograph consists of two chief parts viz. of the guide-cross F representing
the straight lines at right angles to each other, and of the slide-rod H appearing as
a guided straight line. This slide-rod consists of a metal rod bent at right angles,
having any number of edges but preferably of square section, on the longer and
horizontal arm of which two slide-pieces K, K, move, being adjustable anywhere
by means of set-screws (Figs. 1, 2, 5, 6). These slide-pieces have on their under-
side guide-pins J (Figs. 1 & 5) the vertical section of which corresponds in shape
to the groove N (Figs. 1 & 2) sunk into the guide-cross F.
The shorter and vertical arm V (Figs. 1, 5 & 6) of the slide rod H has a
disk S (Fig. 1) adjustable by means of a set-screw and capable of turning about an
axis in a slide piece. This disk S is provided with several arms containing a pencil,
drawing-pen, cutting-wheel, dotting-wheel or other drawing-instruments.
As is apparent from the whole arrangement of the apparatus and the principle
on which it is based, the distance D (Fig. 5) measured from the pencil-point,
i.e. the point of the ellipse to the more distant slide-piece K, represents the semi-
major axis, and d (Fig. 5) measured from the same starting-point to the nearer
slide-piece K, the semi-minor axis. The distance of the two slide-pieces K, K,
is thus the difference of lengths between the semi-axes of the ellipse. The slide-
rod H has a measuring-scale cn its upper side so as to make it possible, to accurately
and surely adjust the slide-pieces K, and K, according to the directions given above
in order to obtain an ellipse of fixed axes.
The guide-cross F, as has already been stated, has a groove N of the same shape
as that of the vertical section of the guide-pins J and the groove N is open at all
four ends for the insertion of the guide-pins (Fig. 2).
In using this ellipsograph one first of all adjusts the slide-pieces K₁ K, according
to the desired size of the axes of the ellipse by the help of the scale engraved on
the slide-rod, and inserts them into the groove N from an open side. In its motion
the pencil describes the path of an ellipse.

page_text: In order to render it unnecessary to hold the guide-cross F with the hand while
using it so as to prevent it from slipping, a few pins & are inserted on its
under-side, by the help of which the cross F may be firmly secured to the
drawing-paper.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what
we claim is:
Ellipsographs, so arranged that a slide-rod (H), holding a drawing-pencil or the
like, is guided by means of slide-pieces (K, K₂) which are adjustable on it in the
groove (N) of a right angled cross (F).
Dated this 25th day of January 1894.
For GUSTAV HEINEL and
CARL BARTH,
B. Brockhues.