IMPROVEMENTS IN PARALLEL RULERS
Year: 1872

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, Gentleman, for the Invention of
"IMPROVEMENTS IN PARALLEL RULERS."-A communication from abroad
by Theodore Bergner, of Philadelphia, State of Pennsylvania, United
States of America.
ealed the 19th November 1872, and dated the 30th August 1872.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson
at the Office of the Commissioners of Patents, with his Petition,
on the 30th August 1872.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County
of Middlesex, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN PARALLEL RULERS," a communication to
me from abroad by Theodore Bergner, of Philadelphia, State of Penn-
sylvania, United States of America, to be as follows:-
This Invention relates to a pecular construction and arrangement of
apparatus to be used by draughtsmen in ruling parallel lines, such, for
example, as occur in what is known as "section lining," and in "flat
tinting," and consists essentially in the combination with a fixed guiding

page_text: blade or T square of a moveable ruler or set square, which latter is
caused to move along the edge of the guiding blade with a regular step-
by-step motion in either direction by the aid of a sharp pointed pall
hinged to a lever or spring mounted on a pivot in connection with the
ruler or set square, such pall engaging into the surface of the guiding
blade. This lever or spring is depressed by the finger of the draughts-
man, which produces a toggle action of the pall, and propells forward
the set square a given distance in accordance with the amount of
depression of the said lever or spring. This movement of the lever or
spring is controlled by stops, one of which consists of an adjustable stop
nut or screw, on releasing the lever or spring from pressure it is
elevated and lifts the pall either by a special spring for the purpose, or
by its own inherent spring, and allows the pall to take a fresh hold. By
reversing the position of the actuating lever or spring and pall on the
pivot the movement of the set square or ruler is reversed.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Henry Johnson in the Great Seal Patent
Office on the 28th February 1873.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Thirtieth day of August, in the year of
our Lord One thousand eight hundred and seventy-two, in the thirty-
sixth year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said John Henry Johnson, Her special license
that I, the said John Henry Johnson, my executors, administrators, and
assigns, or such others as I, the said John Henry Johnson, my executors,
administrators, or assigns, should at any time agree with, and no others,
from time to time and at all times thereafter during the term therein
expressed, should and lawfully might make, use, exercise, and vend,
within the United Kingdom of Great Britain and Ireland, the Channel
Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN PARALLEL
RULERS," a communication to me from abroad by Theodore Bergner, of
Philadelphia, State of Pennsylvania, United States of America, upon

page_text: the condition (amongst others) that I, the said John Henry Johnson;
my executors or administrators, by an instrument in writing under my
hand and seal, should particularly describe and ascertain the nature of
the said Invention, and in what manner the same was to be performed,
and cause the same to be filed in the Great Seal Patent Office within
six calendar months next and immediately after the date of the said
Letters Patent.
NOW KNOW YE, that I, the said John Henry Johnson, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement, reference being had to the accompanying
Drawings, and to the letters and figures marked thereon, that is to
say :-
The said Invention relates to a peculiar construction and arrangement
of apparatus to be used by draughtsmen in ruling parallel lines, such,
for example, as occur in what is known as "section lining," and in "flat
tinting." To indicate sections of objects in mechanical drawing by closely
spaced lines is one of the most tedious manipulations of the practical
draughtsman, requiring a steady eye and skilled hands to produce that
evenness of surface and unblemished appearance which characterizes the
handiwork of an accomplished draughtsman.
Several devices have been constructed and brought forward to facilitate
this tedious parallel ruling, but some of these require alternate appli-
cation of the fingers to two distinct parts, intermittently sliding one
against or within the other, and for the reason that both the ruler and
stop piece are required to slide (the one being held down upon the
surface while the other is moved forward) their manipulation becomes
tedious, and the action of the instrument slow and uncertain in its
guidance.
Others consist of a pall or jumper attached to a set square, and taking
its hold upon the paper or other surface which is being drawn upon
thereby, in some cases injuring the same or the point of the pall
itself.
Now the leading object of this Invention is to provide a more con-
venient and efficacious means of mechanically defining the spaces
between section lines with a view, to expedite this kind of work, to
relieve the eyes of the draughtsman, and to enable a person of moderate.
"

page_text: ability or practice to produce an effect of uniformity and neatness almost
or quite equal to engine dividing, which gives to sectional engravings of
machinery or architectural work a characteristic appearance very difficult
to attain in line drawings executed by hand.
The nature of this Invention, and the construction in detail of the
improved devices will be fully and readily understood on reference to
the accompanying Drawing, which forms a part of this Specification, and
also practically exhibits the efficiency of the instrument by specimens of
section lining executed therewith, and by a few of the many other appli-
cations of the instrument suggested during its practical use. Its facilities
for drawing screw threads, or for laying out the spaces for brickwork,
for large lettering on drawings, &c., some of which are indicated in the
Drawing, and those specimens will suggest many similar and useful
applications of the instrument.
Figure 1 is a full sized perspective view of the improved parallel -
ruling instrument; Figure 2 is an enlarged sectional side view; and
Figure 3 an enlarged transverse section of the instrument.
Modifications in the construction of details of the instrument are
illustrated in Figures 4 and 5, also on an enlarged scale to show the
parts more clearly.
This latter may 2
set square with
the edges of the
The whole consists of a stationary ruler blade A, a movable ruler B,
and a pawl g, taking its hold or bearing upon the blade A, and actuated
as herein-after fully described for imparting an intermittent movement
to the ruler B with variable gradations of space between the lines. The
fixed blade A acts as a guide for the movable ruler B.
for all ordinary work consist of a common triangle or
one of its sides bearing against and sliding along one of
said ruler A. A plate C rests upon the top surface of the ruler A, and
is movably secured to the triangle B by means of a clamping screw d
and nut e. The screw d passes through a slot in plate C (see Figures 1 3
and 3), which provides an adjustment of C in the required direction for
regulating the tension of a light spring f, so affixed to plate C as to bear
against the ruler A on the edge opposite to the triangle B, the latter
being thus steadily held against its guiding edge on A while intermit-
tently advancing. The pawl g, by the action of which the required
advance movement is obtained, bears with its knife edge upon the
top surface of ruler A, for which purpose the plate C is perforated
at a

page_text: In the construction of the instrument represented in Figures 1, 2,
and 3, which, for its simplicity, I have adopted in practice, the pawl g
is jointed at b to a horizontally placed flat bar h of elastic metal, which
bar is at b¹ attached to the outer end of an arm j, projecting horizontally
from a vertical central stud i. The upward extending screwed end of
this stud passes through an opening in the strip h, and above is fitted
with a nut k. The pawl g is actuated in the direction for sliding, the
plate C and triangle B along the guiding ruler A by a light pressure
with the finger upon a button on bar h directly over the pawl. This
depression of h, and consequent vibration of pawl g on its fulcrum, is
limited by the fulcrum piece b bringing up against a metal plate m (as
seen in Figure 4), and thus the forward motion of the triangle B, due to
the toggling action of the pawl is each time positively arrested by the
contact of two metallic surfaces. With the release of the pressure upon
button the elastic bar h, acting as a spring, rises to resume its normal
position until arrested in this direction by the nut k. At each rise of
the bar h the pawl g is released, and following the tension of its take-up
spring n takes a new hold upon the blade A. Now the amount of this
take-up motion of the knife edge horizontally is proportionate to the
movement of its fulcrum vertically, and this vibration of the fulcrum b
with bar h, being limited by the distance between the plate m and nut k,
acting as opposite, stops any adjustment of the nut k to increase or
decrease this amount of vertical vibration will proportionately affect the
horizontal feed of the knife edge, which may thus be regulated for any
desired gradation of space between the lines varying from extreme
fineness to the full feeding capacity of the instrument.
Upon reference to the Drawing it will be seen that the whole of the
described feed mechanism is carried by the central stud i, and that the
lower end of this stud is so arranged within the plate m as to permit its
rotation about a vertical axis. Now this simple arrangement provides
therefore the means of reversing the direction of motion of the triangle B
along the stationary blade A by a half turn of the stud i upon its axis,
the position of the pawl g and its mechanism being thereby instantly
changed for feeding from right to left, or vice versa. The semi-annular
opening a through plate C is provided to admit this swinging of the
pawl g about the axis of i.

page_text: the ruler A must be prevented from moving while the instrument is
in usc.
Now instead of various other feasible modes of securing the blade A,
such as clamps or weights, or sharp points projecting from the under
side of A, and entering the paper or other material upon which the blade
is to be secured, I use by preference a more simple and practically
efficient means, namely, a surface of india-rubber on the under side of
the blade. The strong adhesive property of this substance prevents any
motion of the blade upon a surface of paper, wood, or stone, and the
downward pressure exerted on the button in actuating the pawl g only
tends to increase this hold of the blade A upon the material on which
it rests. On the other hand, the avoidance of more complicated means
of securing the blade adds to its portability and convenience in handling
or adjusting for every new starting point.
2
It will be observed that the pen or other instrument used for drawing
the lines must be steadily maintained in a certain position laterally
against the ruling edge to prevent the slight but perceptible inaccuracy
of the spaces which would occur if the drawing instrument be allowed
to incline to one or the other side from the angle in which it was held in
starting.
The construction of the instrument, shown in Figure 4, differs from
that herein-before described in the substitution of a single bent spring h¹
for the parts h and j, Figures 1 and 2.
The modification represented in Figure 5 is more complicated, and
differs essentially from either of the above, the pawl g being in this case
hinged to a non-elastic lever h², having its fulcrum in a swivel stand ¹.
This swivel only partly takes the place of the stud i in Figures 1, 2, 3,
and 4, while a separate adjusting screw k¹ is provided on this stand ¹ for
limiting the vibrations of lever k², and regulating the feed, which is like-
wise obtained from a pawl g acting in all essential respects alike in the
various described constructions of the instrument.
It will be observed that further modifications of detail are admissible
without thereby impairing the usefulness of this Invention. The
plate C, for example, and its tension spring f might be dispensed with
by guiding the triangle B along a groove in the fixed ruler A, and so
attaching the pawl mechanism directly to the movable triangle, that the

page_text: knife edge of the pawl shall still bear upon the top surface of A, and
act precisely as herein-before described. The plate C is therefore not
necessarily a part in the combination of devices constituting the said
improvement, although the said mode of construction of the instrument
is by preference adopted.
It is of obvious importance to make a fixed blade the guide for the
movable ruler, and to let the pawl take its hold upon this guide blade,
instead of impressing the material upon which the Drawing is made. By
this provision I am enabled to use the instrument on any hard polished
surface of metal or stone with a uniformly reliable action, and without
injury to the surface or to the pawl from abrasion.
I do not claim a ruler moving between stops upon a sliding foot piece,
nor do I broadly claim the use of a pawl or sliding foot piece to actuate
a ruler.
Having now described and particularly ascertained the nature of the
said Invention, and the manner in which the same is or may be used or
carried into effect; I would observe in conclusion that what I consider
to be novel and original and therefore claim as the Invention secured to
me by the herein-before in part recited Letters Patent is,-
First. The combination with a fixed guide blade A and movable
ruler B of a pawl g, taking its hold upon the guiding blade, and being
actuated to impart motion to the movable ruler B, in the manner and
for the purpose set forth.
Second. Arranging the pawl g (when made to act upon the surface of
the blade A) and the parts actuating the same to swing about a common
axis for the purpose of reversing the motion of the movable ruler B
along its guiding edge on blade A in the manner described.
In witness whereof, I, the said John Henry Johnson, have to this
my Specification set my hand and seal, this Twenty-eighth day of
February One thousand eight hundred and seventy-three.
.
J. HENRY JOHNSON. (L.S.)