Improvements in Pantographs, useful for Reproducing upon Metal Plates Lines that Compose a Figure of a Given Pattern.
Year: 1890

page_text: COMPLETE SPECIFICATION.
Improvements in Pantographs, useful for Reproducing upon Metal
Plates Lines that Compose a Figure of a Given Pattern.
We, VINCENT LECOMTE OURDAN & CHARLES ANDREW KOLB, Citizens of the
United States, both residing at 616 I Street North West Washington, in the
District of Columbia, United States of America, Mechanical Engineers, 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 our invention is to produce a pantograph adapted to work easily in
every direction with great rigidity and firmness of movement so as to reproduce with
perfect accuracy and smoothness any pattern which it is set to copy.
Heretofore in pantographs, the construction attainable under the old forms was such
as to prevent their employment in the fine arts, such for instance as engraving, where
a mathematically correct copy is required.
Our invention, while it is adapted to be used for all purposes, is by its peculiar
construction, especially designed for use in the art of exact engraving on hard
surfaces, such as copper and the like. Heretofore it has been necessary to have such
engraving executed by land through the most skilled workmen.
In chart or map
engraving it has also been necessary, to insure that perfect accuracy which is in such
work absolutely essential, to take repeated measurements, in order to verify the
location of each point with respect to every other. Besides this, the process of producing
an improved plate by hand consists of a number of steps, all of which must be
performed with equal care and skill. Consequently the cost of a plate has been very
great, and the time consumed in preparing it has been considerable.
By the use of our invention we can prepare from maps, or other patterns, a perfect
reproduction of the outlines. Our machine being absolutely accurate in its move-
ment, it is not necessary to verify its work by measurement if the pattern upon
which it was executed has first been ascertained to be correct. Besides we dispense
with all the steps necessary to the producing of an engraved plate, except the
actual cutting upon the metal itself.
The figure produced by our machine upon the plate is the exact negative of the
pattern, so that the entire plate is engraved by one operation. It may be necessary to
smooth up the work a little; but that is always necessary according to the old method,
and the amount of it required is not so great where our machines are used as where
the work is done altogether by hand.
From the simplifying of the process and dispensing with the verification hereto-
fore required, the cost of engraving may be very largely reduced, and that without
detracting in the least from the character of the work.
In the accompanying drawings-
Fig. 1 is a plan view of our pantograph, showing the arms of equal lengths;
Fig. 2 is a plan view, showing one of the arms detached from the block, and secured
to the arm adjacent to it;
Fig. 3 is a detached view, partly in section, showing the arrangement of the parts
pivoted to the main track ;
Fig. 4 is a central vertical section of Fig. 1;
Fig. 5 is a top view of one of the blocks which travel on the side tracks ;
and
Fig. 6 one of the blocks which travel on the main tracks ;
Fig. 7 is a detached view of the collar and hinged socket, adapted to move upon one
of the connecting rods;
Fig. 8 is a detached view of one of the connecting rods ·

page_text: Fig. 9 is a section detached of one of the blocks, showing the gib for regulating the
pressure upon the track;
Fig. 10 shows a desirable form of hinge for securing one of the connecting rods to
the other; and
Fig. 11 the same hinge adapted to be secured to one corner of one of the blocks.
Referring to the letters upon the drawings, A indicates a track, which is preferably
made of metal, and is adapted to be firmly secured by clamps or brackets, or any well
known and convenient means, to an ordinary table adapted to have the pattern, and
the plate to be engraved, laid upon it.
In the drawings the track is shown as consisting of a base a, and integral therewith
a rib upon it, the latter being of wedge or dovetail form in cross-section; but any
form of track may be used, some shapes, on account of their cheapness and lightness,
being better adapted to certain purposes than others.
:
Upon the centre of the track A is firmly secured a disk B, which serves as a bearing
for the lateral track arms CC, pivoted above it. D indicates a flange upon the
upright rod that is adapted to pivot the lateral arms together and hold them in place.
It is provided at its upper end with pivoted guys G, and may be screw-threaded
on its lower end to be screwed into an internally serew-threaded hole in the track A,
or it may be passed through the track and secured on the other side by a counter-
sunk nut, or the like.
Any convenient means for uniting these parts may be employed.
H indicates stays, which are preferably made of wire, and are connected at one end
with the guys G, and at the other end with the outer ends of the lateral arms C C¹
to support them.
I indicate blocks fitted to the rib b, and adapted to travel freely upon the
opposite ends of the track A. These blocks are provided with gibs K and adjustment
screws L for regulating their pressure upon the track on which they move.
M M indicate similar blocks, provided with similar gibs and set-screws that are
adapted to move upon the lateral armas CC. The form of block shown in the
drawings is adopted in order to correspond with the track upon which it travels; but
the blocks should always conform with the shapes of their tracks, which may be varied,
as above indicated, in many ways.
Upon each of the blocks M and M' is provided a split collar N N¹, and a thumb-
screw 00', respectively, for increasing or diminishing the size of its internal diameter.
It is immaterial which block carries the tool and which the stylus-they may be
interchanged at will.
The tool adapted to be borne for engraving may, if desired, consist of a rapidly
revolving encased point. This instrument is well known in the art of engraving, and,
as it does not enter into my invention, needs no further description.
Between the blocks I I, and M M³, respectively, are connecting rods P P¹. The
ends of these rods must be directly or indirectly hinged to opposite blocks so
as to allow the blocks to move freely upon their tracks; but the rods may be made
of any convenient shape or size. In the drawings is illustrated a suitable form of
connecting rod.
On each of the inside corners of the blocks I I', and M M' are borne, upon hinges
of any ordinary kind Q, (which hinges are shown to an enlarged scale in Fig. 11,)
internally screw-threaded sockets R, adapted to receive the externally screw-threaded
ends of the rods P P'. It is necessary that the rods shall be adjustable in length, and
we find that the construction shown in the drawings-see Fig. 8-is a convenient
means of accomplishing this purpose. The rods are divided in two parts. The sections
of each rod are made tubular and one larger than the other, so that the smaller may
telescope into it. In the free end of the larger tube we provide a slit S and
lugs T, one of which is internally screw-threaded to receive the thumb-screw U, so
that the parts of the end of the large section of the rod may be clamped together upon
the smaller section, and hold the two sections together. Upon each of the rods P P
I provide a split collar V Fig. 7, adapted to be clamped upon its rod by the thumb-
screw W. These collars are provided with hinged internally screw-threaded sockets X

page_text: (shown to an enlarged scale in Fig. 10), corresponding to the sockets borne upon
the blocks. These sockets are adapted to carry the ends of the rods P P¹ adjacent
to them, respectively, when they are disengaged from the blocks in the manner and
for the purpose that will be hereinafter explained.
The operation of our invention is as follows: Suppose the rods P P¹ to be adjusted
to equal lengths and secured at their ends to the blocks I 11 and M M', then by
operating the block M, which we will assume carries the stylus, and causing the
stylus to follow a pattern, the motion of that block to or from the centre will cause
a movement in the contrary direction of the block M¹. This movement is necessary
to produce the negative plate; because a change of direction in a line toward or
from the central perpendicular, or north and south line must produce a contrary
change of direction in the line upon the plate. But all changes of direction of lines
with respect to a central horizontal or east and west line remain the same in the
negative as in the positive. Therefore a movement of the block M parallel to the
east and west line occasions a corresponding travel of the block M¹ in the same
direction.
The relative movements of the stylus and tool, as just explained, are the result of
the equality in the lengths of the rods P P¹. By equally diminishing the lengths
of the rods secured to the block M, for instance, the movement of the stylus over
a given space will produce a movement of the tool over a smaller space. Increasing
the relative lengths of those arms will produce the contrary effect. By disconnecting
two of the rods from the blocks and connecting them with another rod through the
collar V on it, many other changes in the reproduction of almost endless variety may
be produced, depending upon the relative lengths of the rods and their positions with
respect to one another.
This feature of our invention is adapted to be used to advantage in cutting
plates for illustrations for newspapers, or the like, such for instance as caricatures,
etc., as the outline of the tracing can be grotesquely distorted through the
ordinary manipulation of the machine by simply changing the relations and lengths
of the arms P P¹.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. In combination with a fixed track and sliding blocks I I', adapted to travel
thereon, lateral track arms pivoted to the fixed track, sliding blocks M M' upon said
arms, and pivoted connecting rods between the blocks I l' and M M¹, respectively,
substantially as set forth.
2. In combination with a fixed block and sliding blocks I', adapted to travel
thereon, lateral track arms pivoted to the fixed track, sliding blocks M M' upon said
arms, and pivoted adjustable connecting rods between the blocks I I' and M M³,
respectively, substantially as set forth.
3. In combination with a fixed block and sliding blocks I I', adapted to travel
thereon, lateral track arms pivoted to the fixed track, sliding blocks M M' upon said
arms, pivoted connecting rods between the blocks II' and M M', respectively, and
hinged sockets adjustably borne upon the connecting rods, each adapted to receive
one end of one of the connecting rods when disengaged from its block, substantially
as and for the purpose set forth.
Tugus
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.