IMPROVEMENTS IN DRAWING INSTRUMENTS
Year: 1880

page_text: LETTERS PATENT to Alfred Vincent Newton, of the Office for Patents, 66,
Chancery Lane, in the County of Middlesex, Mechanical Draughtsman, for
an Invention of "IMPROVEMENTS IN DRAWING INSTRUMENTS." A communi-
cation from abroad by Franz Wallegg and Alexander Hirsch, both of Vienna,
in the Empire of Austria.
PROVISIONAL SPECIFICATION left by the said Alfred Vincent Newton at
the Office of the Commissioners of Patents on the 27th January 1880.
ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Mechanical Draughtsman. "IMPROVEMENTS IN DRAWING
INSTRUMENTS." [A communication from abroad by Franz Wallegg and Alexander
Hirsch, both of Vienna, in the Empire of Austria.]
This Invention relates to certain improvements in drawing instruments, whereby
increased facilities are afforded to the mechanical and pattern draughtsman in the
adjustment and use of their instruments.
As an improvement in double jointed compasses the legs are formed to receive
below the joints a detachable bar, which when secured in place by clamping
screws will ensure the parallelism of the legs and hold them firmly in their set
position.
Sockets are formed in the legs to receive the opposite ends of the bar, which fits
snugly therein, and bars of different lengths are provided to suit various spans of
the compass. For compasses of a smaller size, as, for example, double jointed bow
pens, a modification of this removable bar is preferred. In this instance one of
the legs has a vertical transverse slot to permit of the insertion of an adjustable
nut, which is tapped to receive the end of a threaded detachable bar. Sockets are
formed in both legs for the ends of this bar to pass through, and the opposite
end to that which carries the nut is made fast by a clamping screw. The nut is
notched on its periphery to receive a spring pawl, which will hold it in position,
and indicate by a clicking sound the amount of motion given to the nut when
turned for the adjustment of the instrument. The face of this nut may also be
divided and numbered to facilitate the readjustment of the instrument.
To ensure the parallelism of the legs of bow pens and bow pencils used for
drawing small circles I extend the limb of the point upwards to a suitable height,

page_text: where it terminates in a milled head, by which the instrument is to be held. In
this limb I form a socket for a horizontal bar, which projects at right angles from
the pen or pencil leg. Below this bar and parallel thereto. is a second bar projecting
from the pen or pencil leg. This bar is threaded, and passes through a second
socket in the point leg to receive a micrometer nut, as in the last described
arrangement.
As an improvement in the drawing pen it is proposed to adapt to the spring
blades thereof the micrometer nut for adjusting the distance between the nibs.
The screw which passes through the blades is made fast to one, and the nut is
fitted to the screw between the blades. The spring pawle takes into notches in
the nut for the purpose of indicating the amount of its motion, and for holding it
when set. This will apply not merely to ruling pens but also to the pen legs of
compasses.
As a further improvement upon drawing pens it is proposed to fit them on their
back blade with an adjustable guide pin or stud to adapt them for use in con-
nection with the rulers, for which I have applied for Letters Patent concurrently
with the present application. This guide pin will serve either as a vertical support
for the pen while passing over raised portions of the ruler, and thus cause the pen
to miss drawing at certain points; or when the pen is applied to another kind of
ruler the side of the pin or stud will serve as a bearing point for the pen against
the undulating edge of the ruler, and thus facilitate its gliding over an irregular
surface.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Alfred Vincent Newton in the Great Seal Patent Office on the 27th
July 1880.
ALFRED VINCENT NEWTON, of the Office for Patents, 66, Chancery Lane, in the
County of Middlesex, Mechanical Draughtsman. "IMPROVEMENTS IN DRAWING
INSTRUMENTS." A communication from abroad by Franz Wallegg and Alexander
Hirsch, both of Vienna, in the Empire of Austria..
This Invention relates to certain improvements in drawing instruments, whereby
increased facilities are afforded to the mechanical and pattern draughtsman in the
adjustment and use of their instruments, the object being to ensure accuracy of
measurement, and clear lines of an uniform character, or shewing definite varieties
of thickness.
In the accompanying Drawing Fig. 1 is a side view of a pair of double jointed
compasses constructed according to this Invention, and fitted with a pair of points.
The legs below the joint are formed with sockets to receive a detachable smooth
guide bar, which will ensure the lower portion of the legs moving parallel to each
other as the span of the compass is altered.
In this Figure the compasses are shewn expanded, and also in a closed position.
Fig. 2 is an edge view of the compass with the points removed. A, A, are the
jointed legs connected together as usual at the point B, and fitted with a milled
handle C for working the instrument. D is a guide bar fitting into sockets made
in the legs below their joints; and a, a, are clamping screws, which serve when
tightened up against the guide bar to hold the legs firmly in their set position.
Bars of different lengths will be provided to suit various spans of the compass, and
it may be convenient to form a head at one end thereof, as at a', to prevent one
limb of the compass being accidentally slidden of the bar in the act of adjusting
the other limb. The pointed extremities of the legs are screwed in place, and may
therefore be removed and replaced by others; or a pen or a pencil holder may be
substituted for one of the points.
Figures 3 shew this instrument as fitted with a pencil leg in place of one of the
needle points, and Figures 4 shew the instrument as fitted with a pen leg.
In order to provide a delicate adjustment for compasses the above described
improvement is modified, as shewn at Figures 5, which represent in side and edge
view a pair of double jointed pen bows. In this example D is a screwed bar
inserted in sockets below the joints' smooth guide bar, as before mentioned. This
screwed bar is made fast to one of the limbs by a clamping screw E, and it is
passed through a micrometer nut F, which nut is received into a recess formed for
it in the outer face of the leg, and it is covered by a plate G, which forms a bearing
for the hub of the nut. This plate is held in place by a screw, which serves also
to retain in position a spring pawl H that enters the notches in the periphery of
the nut. This nut when turned in either direction indicates by a clicking sound
the amount of motion given to it to contract or enlarge the span of the compass.
The face of this nut may also be divided and numbered to facilitate the readjust-
ment of the instrument. Two, three, or more of these screwed bars of different
lengths will be provided to adapt the compass for working at different spans.
To ensure the parallelism of the legs of bow pens and bow pencils used for
drawing small circles the arrangement shewn at Fig. 6 is employed. The peculiarity
of this instrument is that the limb A which carries the point is extended upwards
to a suitable height, where it terminates in a milled head C, by which the instru-
ment is to be held. Through this limb a socket is formed to receive a horizontal
bar D¹, which projects at right angles from the pen or pencil leg. Below this bar
and parallel thereto is a second bar D, which is threaded, and passes through a
second socket in the point leg to receive a micrometer nut F, as in the last

page_text: described arrangement. By turning this nut the pen or pencil leg will be moved
to or from the point leg, its parallelism therewith being preserved by the two
guide bars D, D¹
The last part of this Invention relates to improvements in drawing pens, which
improvements are illustrated at Figures 7 and 8, Fig. 7 being a front view, and
Fig. 8 an edge view of the pen. In these Figures I, I, are the spring blades fitted
to a handle K. Adapted to the screw L of the blades I is a micrometer nut L' for
adjusting the distance between the nibs. The screw L, which passes through the
blades, is made fast to one of these, and the nut is fitted to the screw between the
blades. M is a spring pawl, which takes into notches in the nut for the purpose
of indicating the amount of its motion, and for holding it when set.
Fitted behind the back blade is an adjustable guiding stud N, which is intended
to adapt the pen for use in connection with the rulers, for which I obtained Letters
Patent of even date with the present Patent. This guiding stud (which is shewn
detached at Fig. 9) is formed with a vertical slotted extension that fits over two
stud pins projecting from the back blade of the pen, and it is held in place by a
clamping screw N¹, which passes through the slot and enters a tapped hole in the
blade. The object of the guiding stud is to serve either as a vertical support for
the pen while passing over raised portions of the ruler, and thus cause the pen to
miss drawing at certain points; or when the pen is applied to a ruler with a wavy
or indented edge the side of the stud will present a rounded bearing surface for
the pen against the undulating edge of the ruler, and thus facilitate its gliding over
the irregular or wavy edge.
Having now set forth the nature of the Invention of "Improvements in Drawing
Instruments," as communicated to me from abroad by my foreign correspondents,
and explained the manner of carrying the same into effect, I wish it to be under-
stood that under the above in part recited Letters Patent I claim,-
First. In combination with double jointed compasses detachable guide bars,
which are passed through sockets in the legs thereof, and are capable of being
fixed in place by binding or clamping screws for the purpose of maintaining the
parallelism of the jointed terminations of the legs, as described with reference to
Figures 1, 2, 3, and 4.
Second. In combination with double jointed compasses detachable guide bars,
which are passed through sockets in the legs thereof, such bars being formed with
screw threads to enter a micrometer nut fitted to one of the jointed legs, as
described with reference to Figs. 5.
Third. The construction of pen bows, as described with reference to Fig. 6,
whereby the parallelism of the legs is maintained.
Lastly. The improved construction of drawing pen, as described with reference
to Figures 7, 8, and 9.
In witness whereof, I, the said Alfred Vincent Newton, have hereunto set
my hand and seal, the Twenty sixth day of July, in the year of our
Lord One thousand eight hundred and eighty.