Improvements in Engraving Machines, useful for Engraving on Metal Plates the Lines forming Compass Faces, and for other purposes.
Year: 1890

page_text: Date of Application, 26th Aug., 1890-Accepted, 22nd Nov., 1890
COMPLETE SPECIFICATION.
Improvements in Engraving Machines, useful for Engraving on
Metal Plates the Lines forming Compass Faces, and for other
purposes.
I, VINCENT LE COMTE OURDAN, a citizen of the United States, residing at
No. 616 I Street North-west Washington, in the District of Columbia, United
States of America, Mechanical 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 :-
My invention relates to machines for engraving compass faces, such as are
used upon ordinary nautical charts for indicating the variations of the compass
in different localities.
My invention consists in the combination and arrangement of parts hereinafter
described for regulating the length of cut of the engraving tool.
In the accompanying drawings:-
Figure 1 is a top view of my machine ;
Fig. 2 illustrates the underside of the ratchet bearing plate that carries the
regulating plate ;
Fig. 2 is a top view of the same, with the regulating plate attached ;
Fig. 3 is a longitudinal central vertical section of Fig. 1 ;
Fig. 4 is a bottom view of a ratchet-carrying plate, provided with a ratchet having
greater number of teeth than that illustrated in Fig. 2;
Fig. 5 is a regulating plate having a greater number of slots than is shown in
Fig. 2b;
Fig. 6 is a detailed view of the cam-operating plunger for securing the carrier
of the machine in fixed relations to its base;
Fig. 7 is a side elevation of my machine, showing in dotted lines the comparative
relations of the movable parts, in different positions.
Fig. 8 is a vertical section of the tool-carriage, showing the relation of it to the
half cylinder that is pivotally carried upon it;
Fig. 9 is an end view of the half cylinder detached, showing one of the
overhanging ends.
Referring to the letters on the drawings, A indicates an annular base, which
is adapted to be set upon the plate to be engraved, in any suitable manner.
I have generally found it desirable, however, to fix it upon a cushion of wax,
which holds it firmly in position and prevents the scratching of the plate. The
inner edge of the base is provided with an annular flange B. Closely fitted around
the flange, and resting upon the base, is an annular carrier C. The carrier is adapted
to be rotated, and by its weight and nice fit will hold its position without mechanical
means to secure it in place, although, of course, they may be used where they are
found to be necessary. Outside of the edge of the carrier C, in an annular groove in
the base A, is provided a ring D, that is susceptible of being rotated upon the base.
It is secured to the base by screws E-see Fig. 3-whose heads move in a dovetailed
annular groove on the underside of the ring D, and whose nuts are countersunk in
the bottom of the base A. F indicates holes of uniform size in the edge of
the base A, and G indicates corresponding holes in the ring D. The holes F
are preferably 360 in number, one for each degree of the circle; and the holes G
are 128 in number, one for each point of the compass. Only a few of each series
of holes are illustrated in the drawings. At H-Fig. 1-is indicated a vernier for
setting the position of the ring D with reference to the base A. Upon opposite sides
of the carrier are secured brackets I 1', that carry within covers J plungers K K¹.
From each side of these plungers project pins L that engage with the surfaces of cam
levers M that are pivoted to the sides of the covers. Within each case is secured a

page_text: spring which projects the plunger downwardly. The spring is not illustrated in
the drawings, because this device is well known and may be varied in many ways.
The cam lever is adapted to lift the plungers and hold them in the raised position.
One plunger is located over the holes F, and is adapted to fit into them. The other
is located over the holes G, and is adapted to fit into them. By means of these
plungers the carrier may be locked to the base or to the ring D alternately. To
the carrier C is secured, at one side of the centre, the dovetailed track N that rests
upon blocks O, and is held in place by screws P, having countersunk heads-
see Fig. 1. Only one end of the track is shown uncovered, so as to exhibit
the screws; but the other end is attached in the same manner, except the block
at that end is made narrower, so as to allow the carrier E to slip over it. Upon the
track N slides a carriage Q, in the middle of which is pivoted, upon lugs projecting
from the carriage, a hollow half cylinder R, that carries upon one end, by means
of the arm S, the engraving tool T. This tool is held in place upon the arm by
the bolt U and nut U₁, and is adapted to be moved radially, or may be made
to describe a circle by rotating the carrier C. V indicates a rod which projects
upwardly from the free end of the arm S, and is provided with an adjustable sliding
collar W, upon which is adapted to be loosely seated a weight (indicated by dotted
lines in Fig. 3) to press upon the engraving tool. Weights of different sizes may be
employed to regulate the depth of cut made by the tool. The cam Y that is pivoted
to the carriage projects under one edge of the cylinder R and is operated by the
thumb-piece Z. When the cylinder rests against the lower part of the cam Y, as shown
in Figs. 3 and 7, the engraving tool is in position to cut. By rotating the cam
the cylinder is gradually turned by the incline of the cam until the engraving tool is
lifted clear of the plate, as shown in dotted lines in Fig. 7.
Coming now to what especially constitutes my invention, A' indicates an adjustable
stop, adapted to be secured to the track by means of the set-screw B. The motion
of the carriage in one direction is limited by this stop, and the carriage is always in
contact with it when it is to be moved for making a cut. Consequently the size
of the compass to be cut is determined by the position of this stop upon the track.
Pivoted at B² on one side of the end of the carriage, opposite to that which carries
the tool, is an arm C that carries the spring-arm D', upon the free end of which
is provided the pawl E¹. E² indicates a slot in the arm C, and E³ a guide within the
slot secured to the carriage. The spring-arm, as shown, is made integral with the
pivoted arm C, and the pawl is made integral with the spring-arm; but these details,
like many others, may be varied to suit convenience. Centrally pivoted to the
adjustable carrier E is a circular plate F¹ that carries upon its underside
the ratchet G. Upon the top of this, by means of the screws H', is removably
secured the regulating plate 1. The number of teeth of the ratchet is made
to correspond to the number of graduations to be cut in each subdivision of the circle.
The regulating plate is usually provided with two or more radial slots, and the
number of slots, and their depth, may be varied at will, the depth of the slots,
and the position of the carrier E*, determining the length of the cut of the engraving
tool. In Fig. 1 is illustrated a regulating plate with six radial slots of the same depth,
and two of greater depth. In Fig. 2b only two radial slots are shown, and in Fig. 2a
ten ratchet teeth are shown. When this regulating plate is used, the circle on
the engraved plate will be divided into a series of graduations, of which every fifth one
will be a short line, and the others little more than points.
The pawl upon the spring arm engages with the ratchet teeth G. The pivoted
arm C carries a hand-piece J', by which it may be turned upon its pivot and motion
communicated to the ratchet G₁, and thereby to the regulating plate. Then, by the
same hand-piece, the carriage may be moved along the track towards the regulating
plate until the finger K2 that is secured to the carriage strikes the regulating plate,
when further motion is prevented. It will be understood from this description that a
cut may be made scarcely longer than a point, or nearly as long as the radius of the
circular regulating plate, or the relative lengths of the cuts may be increased by
increasing the distance between the stop A' and the carrier E. If the finger strikes

page_text: no radial slot in the regulating plate, the relatively smallest mark is made by
the engraving tool; but if it strikes a slot the carriage may be moved, and the tool
will cut until the bottom of the slot is reached.
The length of cut that is made by the tool, while the carriage is being move: from
the stop A¹ to the place at which the finger hits the circumference of the regulating
plate, may be determined by the position of the adjustable carrier E*, with reference
to the stop A¹.
L' indicates a supporting arm projecting from the carriage, and is adapted to slide
upon the way M', secured to the carrier C. This means of support is provided in
order to allow the carriage to move properly upon its base, and to prevent the binding
which would otherwise be occasioned by the weight upon the engraving tool.
The operation of my invention is as follows:-The ring D is first set, by means of
the vernier, to indicate the variation of the magnetic compass at the place on the map,
and is firmly secured to the base. Then the base is centered upon the plate to be
engraved, so that its north and south line corresponds with the north and south
line of the plate. Then to engrave the outer circle, which corresponds to a compass
pointing to the true north and south the plunger K is set into the zero hole F¹. Then
the adjustable stop A' is secured to the track N, and the carriage is moved up against
it. Next the engraving tool, which is always held suspended, except when cutting,
is let down against the metal. Then, by turning the hand piece J¹, a partial rotation
of the regulating plate is imparted by means of the spring-arm connected with
the hand-piece and the ratchet G₁ connected with the regulating plate. Next, without
releasing the hand-piece, move the carriage until the finger upon the carriage strikes
against the regulating plate, when further motion in that direction is prevented.
Then release the hand-piece lift the engraving tool, slide the carriage back to its first
position, and having advanced the plunger K one degree or more, repeat the
operation described as before. The length of cut of the engraving tool, as will
readily be seen, is automatically determined by the operation of the regulating plate.
When the outer circle has been engraved, and the inner one, which shows
the variation of the magnetic needle, is to be engraved, release the carrier from the
base A by withdrawing and locking the plunger from the holes F, and set the other
plunger into the zero hole G. Then repeat the operation above described for cutting
the outer circle, having first set the adjustable block upon the track, so as to limit the
inner circle to the desired size, and also, if desired, having changed the regulating
plate to suit the lengths of cuts to be made..
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
1. In an engraving instrument, the combination with an annular base, a rotating
carrier, a transverse track, and a tool carriage adapted to be moved npon the track,
of a regulating plate adapted to be revolubly fixed to the track, a hand-piece pivoted
upon the tool-carriage, and a connection between the hand-piece and regulating plate,
so that the said plate may be rotated and the carriage moved upon its track by means
of the same hand-piece, substantially as set forth.
2. In an engraving instrument, the combination with an annular base, a rotating
carrier, a transverse track and a tool carriage adapted to be moved upon the track,
of an adjustable carrier E* provided with a revoluble regulating plate, and a ratchet
combined therewith, a pawl connection between the carriage and the ratchet of the
regulating plate, and a pivoted hand-piece carried upon the carriage to operate the pawl
connection between it and the ratchet of the regulating plate, substantially as and for
the purpose set forth.
Ր
1000
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.