DESCRIBING ELLIPSES OF VARIOUS SIZES, AND PROPORTIONS
Year: 1885

page_text: I GEORGE PAYNE GRACE of 28, Bromar Road, Denmark Park, Camberwell S.E.
Mechanical Inventor, do hereby declare the nature of my invention for DESCRIBING
ELLIPSES OF VARIOUS SIZES, AND PROPORTIONS to be as follows, and it consists as
follows:-
Firstly. Of an adjustable frame O. formed of a cross piece of any convenient
length supported at each end by uprights, so as to allow room for the free motion
of the revolving arms H. & L. described below.
A central pivot G. is fitted through the centre of the above frame O. and provided
with a handle at the top to operate the Elliptograph. To the lower end of wh:
an adjustable arm H. as described below is fixed by means of a fixing screw N. and
carries a socket at one end for the motion of another pivot I., to the lower end of
which an adjustable arm L. carrying a pencil holder M. at its end is fixed, anḍ
capable of being varied in length by means of a fixing screw.
Secondly. The elliptical motion given to the pencil holder M. by means of the
handle & pivot G. which work a train of spur wheels C. D. E. F. A. & B. arranged
as follows, so as to give the describing arm L. together with the pencil holder M. an
angular resultant motion round the outer pivot I. equal to the angular motion of
the handle & central pivot G, and the arm H., but in an opposite direction.
The first wheel C. of the above train is fixed on the central pivot G. and works a
double wheel D. & E. at its side, three times its own angular motion, by means of
its upper wheel D. and the lower wheel E. turns, with the same angular motion
as wheel D. viz three times the angular motion of the central pivot G. and in the
same direction, a wheel F. with a cannon pinion fitted round the central pivot G.
under its fixed wheel C., to the lower end of the cannon pinion of which a central
change wheel A. is fixed by means of a fixing screw N, so as to turn in an opposite
direction to the handle & central pivot G, another change wheel B. of equal size
fixed on the upper end of the above described pivot I by means of a fixing
screw J.
•
Thirdly. If convenient the above described Elliptograph having the same
relative motions of the upper wheels C. D. E. & F. & the pivot wheels B & A. can
be fitted with a fuller train of wheels between A, & B, and the adjustment for

page_text: ellipses of any size & proportion can then be made to a fraction of an inch without
detaching any part.
.
Fourthly. It can be adjusted to describe ellipses with any given major and
minor axis by making the outer or describing arm L. reckoned from the pencil to
its pivot I. equal to one quarter the sum of the lengths of the major & minor axes
of the required ellipse, with the pair of change wheels A. & B. each equal in
diameter to one quarter the difference between the lengths of the major & minor
axes of the required ellipse, or vice versa if convenient for small ellipses.
Fifthly. By altering the relative number of teeth in the change wheels A. & B.
of the above described Elliptograph, it can be used to describe an almost unlimeted
number of symmetrical curves and scrolls for ornamental purposes.

page_text: COMPLETE SPECIFICATION.
I GEORGE PAYNE GRACE of 28, Bromar Road, Denmark Park, Camberwell, S.E.
Mechanical Inventor, do hereby declare the nature of my invention for DESCRIBING
ELLIPSES OF VARIOUS SIZES AND PROPORTIONS and in what manner the same is
to be performed, to be particularly described and ascertained in and by the
following statement:-
4
The above named epicyclic elliptograph consists as follows:-
Of an adjustable frame O. formed of a cross piece of any convenient length
supported at each end by uprights adjustable or otherwise for any convenient
distance apart so as to allow room for the free motion of the revolving arms H.
and L. described below.
A central pivot G. is fitted through the centre of the above frame O. and
provided with a bandle at the top to operate the elliptograph, to the lower end of
which a graduated adjustable arm H. is fixed as described below by means of a.
fixing screw N. or otherwise, and carries a socket at one end for the smooth motion
of another pivot I. to the lower end of which another graduated adjustable arm L.
carrying a pen or pencil holder M. at one end is fixed and capable of being varied
in length by means of a fixing screw K.
The elliptical motion is given to the pen or pencil holder M. and the describing
bar L. by means of the handle and pivot G. which work a train of wheels C. D. E.
F. A. & B. arranged as follows or otherwise, so as to give the describing bar L.
together with the pen or pencil holder M. an angular resultant motion round the
free pivot I. equal to the angular motion of the handle and pivot G. with the
attached arm H. round the centre of the instrument, but in an opposite direction.
(See Provisional and Complete Specification Drawings).
The first wheel C. of the above train is fixed on the above central pivot G. and
works a double wheel D. & E. at its side three times its own angular motion by
means of its upper wheel D., and the lower wheel E. turns with the saine angular
motion as D. viz-three times the angular motion of the central pivot G. and in the
same direction, a wheel F. with a cannon pinion fitted round the central pivot G.,
underneath the fixed wheel C., to the lower end of the cannon pinion F. of which,
a central change wheel or otherwise A. is fitted; so as to turn with the same angular
motion as itself, but.in an opposite direction to the handle G. an outer change
wheel or otherwise B. fitted on the upper end of the above described free pivot I.
(See Provisional and Complete Specification drawings.)
The above described change wheels A. & B. can be replaced by other pairs of
wheels of various diameters, and fitted on the cannon pinion of the wheel F., and to
the revolving pivot I. respectively as above described, by means of fixing
Bcrews N. & J. in order to adjust. the distance between the central pivot G. and
the revolving pivot I. for setting the instrument for various ellipses. (See drawing
accompanying Provisional Specification.)
By altering the relative angular motion or number of teeth in the change
wheels A. & B. the instrument can be used for describing an almost unlimeted
number of syminetrical curves and scrolls for ornamental purposes; for an x, number

page_text: of loops the number of teeth in the centre wheel A. should be to the number in the
outer wheel B. as (x + 1.) is to 3.-(See drawing accompanying Provisional
Specification).
The lower motion of the above described elliptograph with the same above
described relative motion of the upper wheels C. D. E. & F. and the central
wheel A. and the outer wheel B. can also be fitted with a fuller permantent train
for setting the elliptograph, in place of various change wheels, which can be
conveniently formed of five spur wheels including the central and outer
wheels A, & B. fitted together in an adjustable linked frame T. T. the central
wheel A. gearing with one of a pair of wheels R. & S. equal to it in diameter and
fitted level and in a line with it, the outer wheel S. of the three having another
wheel S fixed to it below of a larger diameter, and working with the outer
wheel B. of the same diameter, which is fixed to the above described pivot I. at the
end of the adjustable arm H.-If convenient to have the above linked frame
adjustment T. T. longer, one or more pairs of wheels can be added instead of
enlarging the diameter of the wheels of the above described train. By the above
means the adjustment for ellipses of any size and proportion from a dot upwards
can be made to a fraction of an inch without detaching any part..
The above described elliptograph can be easily adjusted to describe ellipses with
any given major and minor axis by making the graduated describing bar L
reckoned from the pencil holder M. to its pivot I. equal to one quarter the sum of
the lengths of the major and minor axes of the required ellipses, and the inner
arm H. from the centre of the instrument to the pivot I, equal to one quarter the
difference between the major and minor axes of the required ellipses, either by
means of suitable change wheels A. & B. or the linked frame T. T. as described
above, or vice versa if more convenient the outer describing arın L. can be made
equal to one quarter the difference between the major and minor axes, and the inner
arm H. one quarter the sum of the major and minor axes.
After adjustment for the size and proportion the required ellipses can be drawn
with their major axis in any relative position with regard to the cross frame O. of
the instrument by unscrewing the fixing screw J. so as to loosen the pivot I. of the
describing bar L. and setting the inner arm H. in the required direction with the
describing bar L. extended in a straight line with it, and then tightening again the
fixing screw J.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
1st The above described epicyclic elliptograph with the above described relative
motion of the central pivot G. and the outer pivot I. with a detachable change
wheel adjustment for size.
2nd The same with a permanent linked train adjustment T. T. for size.
3rd Also the above described setting for various curves.