A New or Improved Apparatus for Drawing Curved Lines.
Year: 1895

page_text: Date of Application, 17th July, 1895-Accepted, 9th Nov., 1395
COMPLETE SPECIFICATION.
A New or Improved Apparatus for Drawing Curved Lines.
I, GUSTAV KÜHN of 4, Promenadenstrasse, Gmuend, in the Kingdom of
Wurtemburg, Manufacturer 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 want of an apparatus suitable for drawing or for increasing or diminishing
the scale of drawings consisting of various curved lines of frequent occurrence
(such as ellipses, star patterns and the like) without having to produce, the said
patterns by geometrical construction has often been felt as a great inconvenience
in various trades. The apparatus described in the following Specification is
designed to obviate this inconvenience.
It consists of a drawing compass which is capable of being employed in a
simple manner for the sketching or drawing of any desired curved lines whether
the same be required in pencil or in Indian ink. For this purpose, the pencil,
drawing pen or like instruments have their course determined by means of a curved
disc which possesses guides whose form corresponds to the form of the curve to he
produced.
The accompanying drawings show an apparatus of this description as follows:-
Figure 1 is a side elevation.
Figure 2 is a plan.
Figure 3 front view.
Figures 4, 5, and 6 show sections on the lines x, y y, and zz respectively of
Figure and the
Figures 7 to 13 show various details of the apparatus.
The frame a provided with a foot-plate a' supports a fixed vertical barbaround
which is placed a movable sleeve e capable of rotating thereon and provided with
a small hand wheel and actuated by a spring c 2 Figure 6.
The lower part of the bar b is formed as a point which is placed upon the centre
of the curve and in order to make the apparatus less liable to shift during the
drawing the plate a' is also provided underneath with a point a 2 (Figures 1 and 3).
Underneath the sleeve c is placed the curved disc d for which purpose the bar b
bears a projection to which by means of a screw e the disc d is made fast.
Figures 11 and 12 show the plan view of two curved discs . Figure 11 shows
an ellipse, and Figure 12 another symmetrical curved form. In addition to these
also unsymmetrical curves can be drawn as well as squares, rectangles and the like
with rounded angles (Figure 13). The curved disc possesses as particularly shown
in Figure 6 grooves d¹ whose form corresponds to that of the curves to be drawn
and which guide the drawing pencil or the like. For this purpose projections f¹, ƒ2
and f3 together engage in any one of the said grooves; the pegs, and 3 are
secured to a bar f, whilst the middle peg f2 is secured to a bar o slightly self-
adjusting in an opening of the bar f (Figures 7, 8 and 9).
The bar bears a projection / placed upon a cross-piece which connects the
two bars i2 and i 2. The bars 2 12 pass through sleeves kk placed at right angles
to the sleeve c and may be made in one piece with the same.
The portion of the apparatus bearing the sleeves kk bears a spring (Figures 2, 4,
and 5) which is connected with a can provided with grooves

page_text: The bars engage in the grooves of the cap 11 whereby the pegs f, f³, ƒ³_if
they are in the corresponding groove of the curved dise should always hold exactly
against the edge of the groove, and effect an exact drawing.
In order that the pegs may be able to pass even, sharp curves and nevertheless
execute a precise drawing the above described middle peg f2 (Fig. 8) is brought
into us For this purpose also the barfon which it. is fixed is made adjustable
on the bar 9 and provided with a slot (Figure 9) through which a peg g³ fixed
by means of the screw g² controls the rod g. Fig. 4.
4
In order to be able to enlarge or to diminish a given curve as may be desire: a
sliding piece m works upon the rod g and is adjustable by means of a screw m¹.
The said piece m is connected to a sleeve m³ by means of an arm m² (Figure 1) in
which there is an adjustable bar n adaptable by means of a screw n'.
The bar n carries the socket O for the pencil'p (pen or other instrument). In
order that the pencil p can adjust itself to any irregularities of the paper or other
material, the said piece is provided with a spring as shown in Figure 10 in which
the pencil holder of is pressed down by means of the spring o².
In order to insert a curved disce the process is as follows:-
After the old disc has been removed the new one is placed upon the projection of
the bar and fastened by means of the screw e. The bars kk are then pushed
forward preferably after releasing the cap and at the same time the sleeve c is
pressed upwards so that the pegs f', 12, f³ can engage in the corresponding grooves of
the disc d. When this has been done the cap is again replaced upon the bars 2, 12.
The drawing of the curve can now begin, that is after the apparatus has been
rightly adjusted and secured by nieans of the points. In order to draw, the
apparatus should be held firmly with one hand and with the other hand the wheel c¹
should be turned whereby the whole mechanism carrying the pencil or other
instrument p will be set in motion. As the bars ff, f³ are engaged in the
grooves of the curved dise the pencil must consequently follow the route corre-
sponding to the form of these grooves whereby the bars will be pushed in or
drawn out of the sleeves kk according as the spring is pressed together or
released. Each curved disc is preferably made with several grooves in order to be
able to produce various forms with one and the same disc, for instance the disc
represented in Figure 6 possesses four grooves whilst the discs shown in Figures 11
and 12 possess two such grooves. An especial advantage of this apparatus consists
in the fact that any curve can be drawn larger or smaller àt pleasure, this is effected
in a very simple manner by the adjustment already described of the pièce m and
the bar n.
The curves drawn are not necessarily of the same shape as those on
the discs. In this manner anyone can easily draw any required number of
symmetrical curves.
"
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed declare that what I
claim is :-
1. An apparatus for the drawing of curved lines characterised by having a
pencil (pen or the like) p whose course is limited and directed by a curved disc d
provided with grooves d' corresponding to the form of the curves to be
reproduced.
2. In apparatus such as is described in Claim the arrangement of guide
pegs, engaging in the grooves d' of the disc d which are on the one side
connected with bars provided with springs and also with the pencil, pen or the
like.
3. In guide pegs such as set forth in Claim 2 the arrangement that the
middle peg f2 is capable of independent adjustment so that even in the case of
very sharp curves an exact guidance of the same in the respective groove is
obtainable.
4. In an apparatus such as is set forth in Claim 1 the arrangement whereby the
controlled motion of the pencil (pen or the like) is provided with a spring adjustment

page_text: in such a manner that it can easily accommodate itself to any unevennesses in
the surface of the drawing material.
5. In an apparatus such as is set forth in Claim 1, the method of adjusting the
pencil, pen or the like by means of the piece m, sleeve m³ and bar n so that any
5 desired curved may be drawn larger or smaller at pleasure.
Dated the 17th dev of July 1895
W. P. THOMPSON & Co.,
Agents.