Background of the invention
Generally, when plotting an ellipse outside of a drawing board, for
whatever the reasons may be, there are no suitable means for carrying this out except
the outdated "gardener's method" or system, consisting of using two pegs or support
points fixed on the focuses of the ellipse to be plotted, and a string tied to said
pegs with a length that is equal to twice the length existing between one of said
focuses and one of the vertexes corresponding to the mid-perpendicular of the line
joining them, such that upon placing a plotting means on the tensed string and shifting
it, maintaining said tension, the eccentricity and oblateness of the ellipse will
But as is understood, this elementary method is not practical when
it is necessary to repeatedly carry out this operation, for example when it is necessary
to obtain a plurality of patterns or equal parts for any purpose.
Likewise, said method has minimum precision and as a result, it is
usually only used for designing gardens or other similar implementations where admitted
tolerances are substantial.
And it is on the basis of this drawback, among others, that the present
invention has been proposed.
Object of the invention
In effect, the invention provides a device for plotting elliptical
figures, having a very simplified design, capable of drawing an ellipse by means
of the simple circular rotation of a crank, which makes it extremely accessible
for carrying out repetitive jobs of this nature.
An object of the invention is to provide the device in question, which
is polyfaceted, as it can also carry out elliptical shaped cuts on sheet materials
or the like by means of simply replacing the plotting tip with a cutting means,
such as a cutting blade when carrying out the cut on paper, cardboard or other laminar
objects of a reduced caliber, or with an oxygen cutting nozzle when it is desirable
to carry out the cut on a metal sheet or similar.
Another object of the invention is to provide said device with simple
alternative means permitting it to carry out circular plots or cuts by simply replacing
An important objective of the invention is to provide a device with
these features in which the design of its parts is conceived such that they can
easily admit the inclusion of drive means which automate the tasks to be performed.
These and other qualities and advantages of the invention will become
easily evident for those skilled persons in the art throughout the following description,
which has been made in reference to the attached drawings and which show a currently
preferred practical embodiment of the device for plotting elliptical figures of
the invention, from among other possibilities, which is given with a purely illustrative
and by no means limiting character, and in which:
Description of the Drawings
- Figure 1- shows a plan view of the device of the invention from which the covering
element has been removed for the purpose of permitting a clearer view of the arrangement
of its operational elements.
- Figure 2- shows an elevational view of the vertical cross section made by the
plane defined by the device's major axis, where the shape and arrangement of its
parts can be seen clearly.
- Figure 3- shows a detail of different plotting tips.
- Figure 4- shows a detail of the base of the device; and
- Figure 5- shows a support for coupling an ink system for the plotter.
As can be seen in said drawings, the most important parts have been
indicated with the following numerical references:
Preferred Embodiment of the Invention
- Base element.
- Channel for belt
- Support arm for the plotting element.
- Plotting element.
- Support for the ink system.
- Support base.
- Knob for gripping.
- Immobilizing screw.
In the drawings, number 1 generically designates a base element and
1a a covering element, both made from a resistant material such as rigid plastic,
aluminum, brass, steel, etc., which have an equal and corresponding elliptical shape,
and which, upon being placed against one another, confine the plotting means between
Said base element 1 is formed by a flat and, as mentioned, peripherally
elliptical body, whose upper surface has in a parallel arrangement and close to
its edges a channel 3 with a rectangular section, the area between this channel
and the edge being slightly downwardly recessed; and on said upper surface, tangent
to the inner wall of the channel 3 and on one of the ends of the major axis of the
ellipse, there is a recessed span with a circular shape, whose center has a vertical,
cylindrical blind passage; and at least two elevated cylindrical projections are
located on both sides of its central point of its said upper surface and on the
line of its major axis.
On the lower part, this base element 1 has a blind threaded passage
in its center which houses a rod 10 which slightly projects above the lower surface
of the element 1 and on both sides of said rod 10, there are two support bases 8
capable of optionally protruding beyond the surface of the central rod 10. And said
rod 10, on the lower surface has a downwardly vertical tip, and likewise, support
bases 8 have a similar tip in their center, all this for a task that will be subsequently
For its part, the covering element 2, which as previously mentioned
is peripherally similar to the base element 1, has cylindrical-section spans on
its lower surface that correspond in position to the protrusions of said base element
1, such that when they are imbedded together, the horizontal shifting between both
parts 1 and 2 is prevented; and on its upper surface, it has a central knob 9 for
A cylindrical through passage with a diameter similar to that of said
blind passage has been made on the covering element 2, corresponding with the location
of the cylindrical blind passage centrally arranged on the cylindrical recess of
the base element 1; and between the blind passage and the end of the part, a new
threaded passage houses a screw 11 capable of optionally shifting beyond the lower
surface of the covering element 2. And a peripheral recess that is similar to and
cooperates with the peripheral recess of the base element 1 for creating a slit
through which the arm of the plotting element 6 protrudes and runs when both elements
are placed against one another, as will be seen below.
These plotting means 6 are constituted by a housed closed belt 4 and
which longitudinally runs inside the channel 3 of the base element 1, which has
means for fixing an "L"-shaped laminar fixing base at an outer point of its length,
a base whose upper wing protrudes between the slit formed by the peripheral recesses
of the base 1 and covering 2 elements, and which in turn, said upper wing supports,
on its free end, optionally and linearly shiftable, an also "L"-shaped support,
whose end of the free wing downwardly houses the optionally removable plotting or
cutting means 6a, 6b, 6c, having a suitable length so that said plotting means are
on the plane defined by the tips of the protruding portion of the rod 10 of the
base element 1.
A pulley 2, joined to a central shaft, is rotationally housed inside
the circular recessed span of the base element 1 and has a diameter corresponding
to the curvature radius of the inner wall of the channel 3 at the tangential point
between both of them; its shaft being housed at its lower end inside the blind passage
and protruding above the upper surface of the covering element 2 through its through
passage, and whose end houses a crank.
In this arrangement, with the screw rod 10 completely introduced such
that its tip is above the tips of the support bases, the assembly supported by said
tips on the laminar surface of the material where the ellipse is to be plotted or
cut, and securing the position of the assembly by means of manual pressure exerted
on the knob 11 of the covering element 2, it is enough to induce the rotation, for
example clockwise, but which can be in the contrary direction, counter-clockwise,
to the pulley 2, by means of the crank housed on its shaft, such that said pulley
2, in its frictional contact with the belt 4, makes it shift in the direction of
its rotation, which in turn will drag the plotting or cutting means fixed to it,
until completing the ellipse.
Additionally, when it is necessary to plot or cut a circle, it is
enough to partially extract the central rod 8 until its tip goes beyond the plane
defined by the tips of the support bases 10, in which case said tip will serve as
a support for the assembly, immobilizing the rotational shifting of the pulley 2
by means of the pressure exerted by the screw 11, and by inducing a rotation to
the entire assembly, the plotting or cutting means will perform a circular shifting.
Certain changes, modifications, alterations, replacements or variations
can be added to the described embodiment example since the preceding detail is giving
solely and exclusively with an illustrative and by no means limiting character.
For example, both the belt 4 and the pulley 2 can be toothed, and
then the shifting of the belt will be carried out by the meshing between them both
instead of by friction.
Likewise, the crank can be replaced with a coupling means to a motor,
the operation would therefore be automated.
Likewise, a circular span housing a pulley with a smaller diameter
than that of the pulley 2 could be arranged on the surface of the end opposite the
major axis of the base element 1, tangent with the channel 3, such that according
to the variation between the diameters of both, different magnitudes for the axes
of the ellipse could be obtained.
The intention is for all these changes and others that could occur
to a skilled person in the art to be comprised within the present invention, as
long as the broadest spirit and scope of the following claims are not exceeded.