IMPROVEMENTS IN WRITING INSTRUMENT
Year: 1875

page_text: LETTERS PATENT to Duncan Mackinnon, of the Town of Stratford, in
the Province of Ontario, Canada, Druggist, for the Invention of
"IMPROVEMENTS IN WRITING INDON
Sealed the 31st August 1875, and dated the 12th July 1875.
COMPLETE SPECIFICATION filed by the said Duncan Mackinnon at
the Office of the Commissioners of Patents, with bis Petition and
Declaration, on the 12th July 1875, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DUNCAN
MACKINNON, of the Town of Stratford, in the Province of Ontario,
Canada, Druggist, send greeting.
WHEREAS I am in possession of an Invention for "IMPROVEMENTS
IN WRITING INSTRUMENTS," and have petitioned Her Majesty to grant
unto me, my executors, administrators, and assigns, Her Royal Letters
Patent for the same, and have made solemn Declaration that I am the
first and true Inventor thercof.

page_text: NOW KNOW YE, that I, the said Duncan Mackinnon, do hereby
declare that the following Complete Specification, under my hand and
seal, fully describes and ascertains the nature of the said Invention,
and in what manner the same is to be performed, in and by the
following statement, reference being had to the Drawings hereunto
annexed, and to the letters and figures marked thereon (that is to
say) :-
My Invention consists, first, of a tapering writing point made of glass,
metal, or other suitable material placed at the foot of and in combination
with a reservoir of ink, the said writing point being held in a detached
holder and centrally perforated with a fine bore or hole, through which
the ink is led down from the reservoir to the paper in a thin thread-like
stream.
My Invention consists, secondly, of an automatically-acting valve
(seated on the top of the writing point proper, closing the ink bore or
duct), and a spindle attached to the said valve passing downward through
the bore of the writing point, the duty of the valve being to shut off the
flow of ink when the operator ceases writing, and the duty of the spindle
in combination with the valve being to start and keep up a continuous
and even flow of ink. The valve consists of a properly weighted and
fitted head, to which is attached a fine tapering spindle of metal passing
downward through the bore of the writing point and extending a short
distance beyond the extremity of the said writing point when the pen is
not in use. Thus the operator when he places the point on the paper
lifts the valve, allowing the ink to flow.
My Invention consists further of an air-conducting tube passing
downward through the centre of the ink reservoir and terminating near
the lower end of the said reservoir. The air tube is cither loft open or
partly closed by a perforated diaphragm at its lower end. The object of
this part of my Invention is to assist the downward flow of the ink
from the reservoir, and at the same time to steady the regular flow
therefrom.
My Invention consists, lastly, of a rod placed within and extending
the whole length of the air tube, the lower enlarged end resting on the
top of the writing point valve in combination with a screwed cap, the
object of this part of my Invention being to enable the valve to be
held to its seat to prevent the escape of ink when the pen is not
in use.

page_text: In the accompanying Drawings Fig. 1 is an enlarged sectional view of
an instrument constructed according to my Invention; Fig. 2 is a sectional
plan at a, a, of the same; Fig. 3 is a sectional plan at b, b, of the same;
Fig. 4 is a sectional plan at c, c, of the same; Fig. 5 is an clevation.
A is the instrument, consisting of the two main parts, B the ink
reservoir, and C the writing point holder. The reservoir B is a tube of
any suitable diameter hermetically closed at the upper end, and con-
structed preferably of metal or other material non-corrosive under the
action of ink. The tube is tapped at the lower end to receive the
threaded end of the detacheable writing point holder C, which holder is
also preferably composed of a non-corrosive substance.
The upper portion of the bolder for a suitable distance is a parallel
cylinder, the remainder tapering regularly to a smaller diameter forming
a seat for and containing the major portion of the writing point E. The
writing point E is made of glass, of a non-corrosive metal, or any other
non-corrosive material suitable for the work. It is a hollow parallel
cylinder at its upper end E' for a suitable distance, but finishes downward
therefrom to a point of suitable fineness in a regular taper centrally
perforated by a fine borc or ink duct e, which bore is closed at the upper
end by a valve F. The entrance of this bore is funnel shaped.
→
To the valve F is attached a fine spindle F¹, which passes downwards
through the bore e, projecting a short distance beyond the extreme
end of the writing point. A suitable seat is ground for the valve F
to rest upon in order that there may be no leakage when the valve is
in place. The sides of the valve may be plain, grooved, or tapering as
desired.
G is an air-conducting tube leading from the top of the reservoir and
terminating at a point a short distance from the top of valve F.
The lower end of this tube is either left open or is partly closed by a
perforated diaphragm G¹.
G³ is a rod pressing upward through the tube G; H is a capping
piece screwed on the outside of upper end of ink reservoir, and per-
forated with one or more inlet air holes h. The inner face of the
crown of this cap is lined with rubber or other suitable material, and
may be adjusted by screwing the cap up or down to releive or bear
against the top of the rod G with the object of firmly closing the ink

page_text: valve on its seat to prevent the escape of ink when the pen is not in
use from the point, and further to close the top of the air tube to prevent
the leakage of ink when the pen is laid in any position from the
top.
Having now defined the parts of my Invention its operation may be 5
described as follows:-For the purpose of this description the reservoir
is supposed to be filled with ink and the pen in the hand of a
writer. The moment the paper is touched to commence writing the
spindlo F is pushed up, lifting the valve F and allowing the ink to flow
to the point in a thin thread-like stream of a uniform size, which stream 1
is transferred to the paper and fashioned into words by the motions of
the operator in the usual way.
Every time the operator lifts his pen the valve F closes, immediately
shutting off the supply of ink, if only for the instant between tho
formation of detached letters. This constant lifting and lowering of 1
the valve and spindle in combination with the air admitted by the tube
starts and keeps up an even flow of ink down the bore to the point of
pen, and also prevents any granular or sticky accumulation or deposit.
To replenish this reservoir unscrew the part C, nearly fill the chamber
round the air tube, and scrow the piece C on again. The joint between 2
the two picces is made water-tight by any of the usual means, such as a
leather or rubber washer.
•
In the construction of the different parts of my Invention I do not
wish it to be understood that I confine myself to the use of any specified
material, but I prefer and advise that non-corrosive substances should be 2
employed, especially in the construction of the writing point and operating
valve. Further, while the cylindrical portion of the writing point is not
necessary to the perfect operation of the instrument, still it is preferred
that it should be used, both because it affords a means of fastening the
point to the holder and a suitable receptacle for the ink valve.
I claim as my Invention,-
1. The writing point E, constructed of glass, a non-corrosive metal, or
other suitable non-corrosive material, and consisting of the tubular
portion or valve chamber E' and tapering point E, with ink bore or
duct e, in combination with the valve F and spindle F¹, arranged and a
operating substantially as described and for the purpose specified.

page_text: 2. The detachable holder C, with writing point E and valve F in com-
bination with the ink reservoir B, arranged and operating substantially
as described and for the purpose specified.
3. The air tube G leading a column of air to or near the foot of the
ink reservoir B, for the purpose of assisting and regulating the flow of
ink therefrom, substantially as and in the manner described.
4. The perforated cap H and rod G² in combination with the ink
valve F and ink reservoir B, arranged and operating substantially as
described and for the purpose specified.
In witness whereof, I, the said Duncan Mackinnon, have here.
unto set my hand and seal, the First day of May, in the year of
our Lord One thousand eight hundred and seventy-five.