Improvements in Pantographs.
Year: 1889

page_text: Date of Application, 19th Feb., 1889
Complete Specification Left 19th Nov 1889-Accepted 18th Jan 1890
PROVISIONAL SPECIFICATION.
Improvements in Pantographs.
A communication from abroad by LOUIS COTÉ, of Paris, in the Republic of France.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both
in the County of Lancaster, and 323, High Holborn, in the County of Middlesex,
Civil Engineer, do hereby declare the nature of this invention to be as follows :-
-
The object of this invention is a pantograph which is composed of a series of
rulers or rails, each carrying a tracing or marking device, and arranged in a
parallel position upon a parallelogram in such a manner as to make with the same, all
movements in any direction, without changing the points of connection. Thus, by
following the outlines of an original drawing, a certain number of similar repro-
ductions can be obtained simultaneously, the respective dimensions of which gradually
diminish or increase.
A second feature of this invention is an arrangement by means of which the pivot,
about which the whole system of the pantograph turns ean easily be moved in any
direction. This arrangement admits of deforming the reproductions in such a way,
that they are no more geometrically proportioned to the original, which is of great
importance for certain industries.
Most pantographs hitherto known have the inconvenience that the apparatus must
be taken to pieces, or that. a difficult operation of adjustment becomes necessary for
changing the dimensions-of the-reproductions. This inconvenience is obviated by an
arrangement by means of which, in avoiding the direct connections of the rails,
they are jointed in movable bushes, in which they can slide lengthways, so as to be
lengthened or shortened, without undoing the connections.
Finally, an improvement has been applied to the tracers, which according to this
invention are movable in vertical direction at the ends of the rails, and are pressed
slightly downwards by a light spring or by a weight on the top of each tracer, so that
the pencil at the foot of the tracer is held to travel on the surface of the paper, even if
the same should offer some irregularity.
Dotud thin 10th of 1000
COMPLETE SPECIFICATION.
Improvements in Pantographs.
A communication from abroad by LOUIS COTÉ, of Paris, in the Republic of France.
I, WILLIAM PHILLIPS THOMPSON, F.C.S., M.I.M.E., of the Agency for Foreign
Patent Solicitors, 6 Lord Street, Liverpool, and 6 Bank Street, Manchester, both in
the County of Lancaster, and 323, High Holborn in the County of Middlesex, Civil
Engineer, 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 object of this invention is a pantograph composed of a series of rails or rulers,
each carrying a tracing or marking device and arranged in a parallelogram in such
a way that all movements in one plane can be made without changing the points
of connection. There can be thus obtained, by following the outlines of an original
drawing simultaneously, a certain number of similar reproductions, the respective
dimensions of which gradually diminish or increase.
A second feature of this invention is a special arrangement by means of which the

page_text: pivot, round which the whole system of the pantograph turns, can be easily moved and
in any direction on the drawing. This arrangement admits of deforming the repro-
ductions in such a way that they are no longer geometrically proportional to the
original, which is of great importance for certain industries.
Most pantographs hitherto known have the drawback that the whole apparatus must
be dismounted or that a difficult operation of adjustment becomes necessary in order
that the dimensions of the reproductions may be changed. This inconvenience is
obviated by an arrangement by means of which, in avoiding the direct connections
of the rails or rulers, the same are jointed in movable bushes, wherein they can slide
so as to be lengthened or shortened without taking the apparatus to pieces."
In the annexed drawings
Figure 1 is a plan view of the pantograph.
Figure 2 is a partial section of same on line y y of Figure 1, representing a rail or
rule with its tracer.
Figure 3 is the moving device for the pivot.
Figure 4 shows the movable bushes in which the rails or rulers can simultaneously
slide and turn, this view is a section on line x a Figure 1.
Figure 5 is a section on line z Figure 3.
Figure 6 shows the result obtained in the reproduction by moving the pivots.
The apparatus supported by three legs fffis composed of two long rails or rules a
and connected at M³, two other rails c and d hinged at M³, are connected to
rails a and b at points M and M³; a crossbar d parallel to d connects at N and N¹
the two parallel rails & and c.
The rails gggg yg rivetted on the two crossbars d and dat equal distances,
and parallel to each other and to the exterior rails b and c, are each provided at their
respective ends with a tracing device as shown at h³, all being situated in a straight
line from pivot O to the main tracer HI' of rail b.
The distance O M and H M' can easily be lengthened or shortened in order to
change the size of the reproductions by displacing the rails a, b and c in their movable
bushes, the construction of which is shown in Figure 4.
Two bushes, ask and of the same section as the rails, are connected by means of
a rivet with sunk in bead, and rails a and b, after being placed in the desired positions,
are secured by screws k² k³.
A special improvement in the construction of the tracers is shown in Figure 2.
The same are movable in vertical directions at the extremities of rails and are
pressed slightly downwards by a light spring or by their own weight, or, if that
is found to be insufficient, a little weight L may be secured to the top of each
tracing device, so that the pencil at the foot of the tracer is always held to travel on
the surface of the paper, even though its surface should offer some irregularity.
Each tracer is placed in a bush 7 secured to the respective rail by the shoulder /*
below and the nut 1 above.
If one or several reproductions of an original in enlarged or diminished scale are
to be drawn and it is desired to diminish, at the same time, one of the special
dimensions in a proportion differing from the geometrical reduction, the pivot O of
the apparatus is moved as shown in Figure 6, wherein hhh is the reproduction of
the original H H H (the pantograph having turned on the pivot when in its central
position 0); the two figures are of course geometrically proportional, their dimensions
being in the proportion R: "= =R':
In order to diminish one dimension (say), more than the other R, namely, the
width of the figure more than the length, the following procedure is observed.
By means of a special arrangement which will be hereafter described, the pivot of
the pantograph is moved in the same direction in which the border line of the figure
will be disproportioned in consequence of the desired difference, in the dimensions.
This movement is effected after a correct reproduction h h h has been drawn..
As this displacement of line. h h will be effected in the direction of the arrow
P the
pivot must be moved from its central position O into the eccentric, position 06, and
the pantograph will take the position indicated by the dotted lines.

page_text: In following now a second time with point. H along the outlines of the original, the
tracer being in working position, the latter will give also a perfectly geometrical
reproduction of H H H, namely, hº hº hº.
To obtain a drawing diminished at its lower side, it is only necessary to make use
of the space enclosed between the displaced base line h° ° and the point of the first
reproduction, which was made when the pivot was situated in its central position.
Thus there is obtained the hatch lined figure, the width of the same, 20, being no
more in the same proportion to its length R as: R.
If it is desired to obtain a figure increased in width, the one bounded by the
exterior lines (1º º, hº 1º, h h) is taken, the two lines ho ho being produced downwards
to meet the horizontal line hh, which for this purpose is produced slightly in each
direction. When it is desired to extend the figure still further downwards, the pivot
of the pantograph is placed below its centre as at O', or, in order to add on a piece to
the left hand side of the figure, the pivot is placed to the left of its central position
as at 02.
The device, by means of which the pivot can be displaced, consists in a plate A
fixed on the drawing plan, carrying in its centre a revolving lever m provided with a
sliding bush P, which, by means of a screw p', may be secured in any position on the
turning lever m. The upper part of screw p¹ receives the end of the rail a of the
pantograph, and serves as a pivot. In order to secure the lever m in any desired
position, the same is provided with a spring n screwed to it by screw n². This spring
carries a little bolt n¹, which traverses the lever m and engages its end into small
holes o bored into the plate A. But these holes can be dispensed with, and the
operator is free to choose any position, the friction being sufficient to retain the
lever m in any desired position. It is obvious that the same result may be attained
by any other means, for instance, by screwing the pivot into holes arranged on
the surface of the plate, etcetera.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated to
me by any foreign correspondent, I declare that what I claim is :-
1. In a pantograph, the disposition or arrangement of a certain number of parallel
rails such as gggggg in order to trace simultaneously several reproductions in
geometrical proportions to the original, the dimensions of which gradually increase
or diminish substantially as herebefore described and shown in the accompanying
drawings.
2. In a pantograph, the application of tracers moving freely in the ends of rails in
vertical direction and automatically pressed on the tracing surface by weights or light
springs.
3. In a pantograph, the arrangement of movable bushes allowing the rails to slide
lengthways and to turn at the same time, substantially as described.
4. In a pantograph, the application of the device for moving or displacing the
pivot or point for the purpose specified.
Dated this 18th day of November 1889.
WM. P. THOMPSON & Co.,
Agents for the Applicant.