AN IMPROVED PENCIL SHARPENER
Year: 1857

page_text: LETTERS PATENT to Samuel Darling, of the State of Maine, of the United
States of America, for the Invention of "AN IMPROVED PENCIL SHARPENER."
-Partly a communication from Toconk W Seman
Sealed the 16th February 1858, and dated the 18th December 1857.
COMPLETE SPECIFICATION filed by the said Samuel Darling at the
Office of the Commissioners of Patents, with his Petition and Declaration,
on the 18th December 1857, pursuant to the 9th Section of the Patent
Law Amendment Act, 1852.
TO ALL TO WHOM THESE PRESENTS SHALL COME, BE IT
KNOWN, that I, SAMUEL DARLING, of the State of Maine, of the United
States of America, am in possession of a new and useful Invention of
"AN IMPROVED PENCIL SHARPENER," (the same having been partly invented by
me, and partly communicated to me by Joseph W. Strange, a foreigner residing
abroad,) and I do hereby declare that the said Invention is fully described, or
the nature thereof, and the manner in which it is to be performed fully set
forth and illustrated in the following Specification and the accompanying
Sheet of Drawings, in which Figure A represents a view in perspective of the
pencil sharpener now in common use; Figure B denotes a longitudinal section
of the same, with a pencil in the process of being sharpened inserted in it;
Figure C exhibits the pencil when sharpened.
In its general form this pencil sharpener resembles an ordinary candlé

page_text: extinguisher, it being a hollow cone with a handle or ring at its apex. This
hollow cone is formed into a conical cutter by making in its side a longitudinal
slot, and by fixing in this slot a thin blade or knife with its edge. towards the
interior of the cone, and projecting slightly beyond the inner surface of the
cone.
To sharpen a pencil by means of this instrument, the latter is held by the
ring between the finger and thumb of one hand, while the point of the pencil
held in the other hand is inserted into the cone and rotatod under slight pres-
sure against the knife, causing it to remove a shaving from the circumference
of that part of the pencil which is to be reduced to a conical form, the shaving
being parallel to the surface of the cone to be formed, and continuing to be
pared off like the unwinding of a spiral, until the point of the pencil is reduced
to a solid cone, the counterpart of the hollow cone of the instrument. During
this operation the wood and lead are simultaneously reduced by a shaving of
equal thickness taken from both. As the lead is brittle, the shaving taken
from it is pulverized by the act of cutting, and this pulverised lead falling
upon that part of the knife which is cutting the wood rapidly dulls its edge,
which but for this interposition of gritty matter would long retain its sharpness.
As a smooth point cannot be formed on the pencil without a sharp knife, this
dulling of the knife by the mixture of the grit from the lead with the shaving
from the wood greatly impairs the efficiency of the instrument. Further, as
the wood and lead are cut simultaneously, a shaving of equal thickness is
removed from both, and the slot which forms the slope of the cutter must be
sufficiently wide to permit the shavings to escape freely, leaving the point of
the lead with too little support to enable a material so brittle to sustain the
pressure of the cutter, hence the point of the lead is almost invariably broken
off (and left in the form of a jagged and irregular frustrum) in the act of
sharpening the pencil. This broken point is highly objectionable, not only on
account of its irregularity, but also of its bluntness. There are other pencil
sharpeners known, which being in very limited use and much more imperfect
than this, it is unnecessary to describe their defects.
"
n
To remedy the above specified and other defects in the pencil sharpeners
heretofore known is the principal object of my Invention, which mainly con-
sists in so constructing the instrument that it will in sharpening a pencil
reduce the wood separately from the lend, thus avoiding dulling the knife,
which results in the previous instruments from reducing the wood and the lead
simultaneously, and thereby bringing the grit from the lead in contact with
the edge of the knife; and I accomplish this object by combining with the
conical hollow cutter for reducing the wood of the point of the pencil a smallor

page_text: hollow conical cutter for reducing the lead of the point of the pencil after the
wood has been reduced by the larger cutter, the hollow cone or throat for
reducing the lead being provided with a knife or knife edge suitable to the
reduction of the lead, and the two being constructed so as to effect the reduc-
tion of the lead to a cone without breaking off the apex. By thus saving the
apex or point of the lead and utilising it, a pencil will do from five to twenty
per cent. more work than when sharpened by the ordinary pencil sharpeners,
as above explained.
My improved pencil sharpener is shewn in perspective in Figure 1 of the
accompanying Drawing, and in section in Figure 2, the pencil being shewn in
the latter Figure as in process of having its wood reduced.
Figure 3 is a similar section, representing the pencil with its point inserted
in the smaller cutter throat, and in the process of having its lead reduced;
Figure 4 is a similar section in a reversed position, to shew the cutters or
cutting edges; Figure 5 is a horizontal section at the line x, x, of Figure 2;
Figure 6 represents the pencil partially pointed, with its wood only reduced,
preparatory to having its lead reduced; Figure 7 represents a pencil with the
sharpening completed and the point left in a form suitable for writing;
Figure 8 denotes a pencil with the sharpening completed, with the point in
the form of a double cone and suitable for the use of draughtsmen, the lead
being allowed, to protrude from the wood further than in that shewn in
Figure 7; the last-mentioned form of point being produced by cutting away
the wood in the larger conical cutter further back from the end of the lead
than would be required to form a point in which the wood and lead form a
common cone, and then reducing the end of the lead to a point in the smaller
conical cutter, leaving between this cone on the end of the lead and the wood
a cylindrical column of lead of greater or less length, as may be required.
In its general shape my improved pencil sharpener, like those in common
use, resembles a candle extinguisher, and it may be made either plain or with
an ornamental exterior, as shewn in the Drawing, according to the taste of
Abe manufacturer.
In Figures 1 and 2 (a is a hollow frustrum of a cone armed with a knife b,
attached to the slot c in its side for reducing the wood; this hollow frustrum
terminates in the space d within the ring or handle (e), into which space the
lead rotrudes while the wood is being reduced. A second and smaller hollow
cone whose axis is at a right angle to that of the cone or throat a is formed
in the ring e at its junction with the cone a, and this smaller cone has a narrow
slot in its side armed with a knife for reducing the lead to a point, as already
described. The knife with which the slot in the larger hollow cone is armed
1,

page_text: ends into the smaller cone,
This knife should be made
is mado in this example to extend with one of its
and this end is sharpened to form a cutting edge.
of well tempered steel. The rest of the instrument may be made of brass or
some soft metal, which may be conveniently cast in a mould.
I do not claim the pencil sharpener made as shewn in Figures A and B
but what I do claim is, an improved pencil sharpener as made with sepa--
rate cutting edges and throats, formed so as to enable a person to reduce the
wood and lead of a pencil separately, in manner substantially as herein-before
specified.
I also claim the arrangement of two conical throats with one blade, having
a cutting edgo for each throat.
I also claim the arrangement of a lead receiving recess (d) in the ring or
handle (e) and in connection with the throat (a) of the wood reducing cutter,
and in advanco of the same, as specified.
In testimony whereof, I have hereunto set my signature and seal, this
26th day of November, 1857.