Improvements in Apparatus for Drawing Ellipses.
Year: 1884

page_text: Improvements in Apparatus for Drawing Ellipses.
I, WILLIAM PHILLIPS THOMPSON Fel. Inst P.A of the Agency for Foreign
Patent Solicitors 6, Lord Street Liverpool in the County of Lancaster and
323 High Holborn in the County of Middlesex, Civil Engineer do hereby declare
the nature of the said invention for "IMPROVEMENTS IN APPARATUS FOR DRAWING
ELLIPSES (a communication from abroad by Henry T. Hazard of Los Angeles
in the state of California, United States of America, Attorney-at-Law), to be as
follows:-
"
This invention relates to devices for drawing ellipses; and the improvement
claimed, consists principally in constructing and adapting an attachment for a
drawing pen or pencil and combining the same with a pair of dividers, by means
of a cord, in such a manner as to enable one therewith to conveniently and
accurately draw an ellipse of any desired size and proportion.
To accomplish this I provide a pair of dividers with needle-points having an
annular groove close to the end of each. I then provide an attachment adapted to
be fastened upon a pen or pencil, and having a drum mounted thereon, adapted to
wind up a cord which I attach thereto, and which passes along a groove in the
attachment and out through a hole in the end of the attachment; whereby the
cord is held close to the end of the pen or pencil avoiding thereby any irregularity
in the ellipse. Both ends of the cord are fastened to a drum mounted on the
attachment, and the loop thus formed passes through a hole at the end of the
attachment and diverges therefrom.
The end of the attachment being close to the point of the pen or pencil.
In drawing an ellipse, the points of the dividers are placed in the foci points of
the desired ellipse; the loop is placed around the points so that the cord will run
in the grooves thereon.
The drum, to which the cord is attached, by both ends, is then rotated whereby
the loop of the cord will be correspondingly shortened or lengthened until the
point of the pen will rest upon the line of the desired ellipse when the cord is
drawn taut.
The pen is then made to sweep around the dividers, and will be guided by the
cord, to draw the ellipse.

page_text: Improvements in Apparatus for Drawing Ellipses.
I, WILLIAM PHILLIPS THOMPSON, Fel. Inst. P.A. of the Agency for Foreign
Patent Solicitors, 6 Lord Street, Liverpool, in the County of Lancaster, and
323 High Holborn, in the County of Middlesex, Civil Engineer, do hereby declare
the nature of the said invention for "IMPROVEMENTS IN APPARATUS FOR DRAWING
ELLIPSES," (a communication from abroad by Henry T. Hazard, United States) 5
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 instruments for drawing ellipses, and consists in
constructing and adapting an attachment to a drawing pen or pencil, whereby a
cord to form a loop can be mounted thereon so as to allow the loop to be made 1
larger or smaller at pleasure; and in combining the same with the points of a pair
of dividers to guide a pen or pencil in drawing an ellipse.
Fig. 1. shows a pair of dividers and a pen having my attachment: all being in
position for drawing an ellipse.
Fig. 2. is a view of the inner side of the pen attachment.
Fig. 3 is a view of the outer side of the same.
Fig. 4 is a section of the same on line xx Fig. 3.
Fig. 5 is the grooved needle-point for the dividers.
Fig. 6 is a view of the inner side of the pencil attachment.
Fig. 7 is a section of the same on line y y.
Fig. 8 is a pencil provided with the attachment.
The dividers A, are provided with needle-points P, P having an annular groove Q
near the end of each.
The attachment for the pen has a blade D, which is fastened to the pen by the
thumb screw G,-which passes through a hole in the blade, and is held firmly
in place by two projections F, at the upper end of the blade, which fit upon each
side of the pen; The lower end of the attachment is slightly concave to conform to
the shape of the pen, and snugly fit thereon.
A drum E, having its outer flange milled, is mounted at one end of the blade ;
and a groove O, extends therefrom to a hole in the lower end of the blade.
A fine cord, I, is attached by both of its ends to the drum E, and the loop formed
thereby passes along the groove and out through the hole at the end of the blade;
where it diverges to pass around the points of the dividers.
The needle points, P, of the dividers, have an annular groove Q, around the end
of each to retain the cord at that point.
The drum E, projects slightly beyond the inner face of the blade so as to press
against the pen or pencil and produce friction to prevent the cord from being
unwound too easily.
The attachment is adapted to a pencil by removing the points F, and providing
two bands L and T to encircle and clasp the pencil: which is cut to fit tightly
therein.
To draw an ellipse, place the points of the dividers in the foci points of the
desired ellipse, and encircle them with the loop, which can be then enlarged or
decreased by rotating the drum until the pen rests upon the line of the desired
ellipse when the cord is taut.

page_text: Then draw a line with the pen around the points of the dividers; taking care
to keep the cord taut, and turning the pen so as to keep its blades parallel with
the line of movement. The cord will guide the pen to draw the desired ellipse.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, I declare that what
I claim, is
1. An ellipsograph consisting of a pen provided with a drum or winding device;
a cord confined near the point of the pen, and there allowed to diverge to form a
loop; the cord being attached to the winding device:-and two stationary needles,
around which the cord slips to guide the pen in drawing an ellipse.
2. In an elipsographic attachment for a pen or pencil, a blade, perforated at one
end to admit a loop of cord, and having a drum to which the cord may be attached ;
whereby the size of the loop may be regulated by rotating the drum.
3. In an ellipsograph, a pair of dividers, each of the legs of which has an annular
groove near its point, in combination with a drawing pen provided with a winding
device to which a pen-guiding-cord is attached substantially as shown whereby it
is made adjustable as to length.
4. In an ellipsograph, the attachment A, baving a drum E the cord J, needle-
points PP, grooved as shown, and the dividers and drawing pen, all being in
combination substantially as shown and described.
5. In an ellipsograph, the combination of two needles or points, a pen or pencil
provided with a drum or take-up device, a cord attached to said drum and made
to diverge to form a loop encircling the points; such cord being confined or clasped
at the point of divergence, substantially as shown, whereby the size of the loop is
made constant while the loop is being used.
6. In combination with a pair of dividers having their legs circumferentially
grooved close to their points and thereby adapted to hold a pen guiding cord close
to the paper in drawing an ellipse, a pen-guiding-cord seated in said grooves, and
a drawing pen attached to said cord, substantially as described.
7. In an ellipsograph, the combination of the blade A, having attached thereto
the cord-winding drum Z, and the pen-guiding-cord, in combination with a
drawing pen and a pair of dividers, the legs of which have an annular groove, all
substantially as described and shown.
8. In an ellipsograph, the combination of a pair of dividers, a drawing pen, a
drum-carrying blade adapted for attachment thereto, and having a perforation
near its point, and a cord passing through such perforation and attached to said
drum substantially as set forth.
9. In an ellipsographic attachment for a pen or pencil, a cord winding drum
extending beyond the line of the face of the blade of the attachment, so as to
impinge against the pen or pencil and produce friction when the attachment is in
place; whereby the drum is prevented from slipping and loosening the cord.
10. In an ellipsograph a pen guiding cord attached to a winding or take up
device carried by a pen or pencil; whereby the cord may be adjusted as to length.
11. An ellipsographic attachment for a pen or pencil, provided with a winding
or take up device, and having a cord secured thereto by its ends and diverging
from near the point of the pen or pencil to form a loop to encircle two points or
needles and guide the pen or pencil in drawing an elipse.
A
WP. THOMPSON & Co.,
Agents for the Applicant.