Improvements in Apparatus for Sharpening Pencils.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Sharpening Pencils.
I, HEINRICH AUGUST HERMANN GUHL, of 26/29 Herrengraben, in the City of
Hamburg, Germany, Merchant, do hereby declare the nature of this invention to be
as follows:-
This invention relates to apparatus suitable for sharpening writing and drawing
pencils (such as lead, chalk, and slate pencils) by means of a rotary milling disc which
is provided with a holder for the point-end, which is arranged close to the milling tool
and which has made in it, by one sided bevelling, a slot through which the point of the
revolving pencil is securely guided into the range of action of the cutting edges of
the milling tool. In proportion as the cutting edges of the milling tool render the
point more and more conical, the point bears more and more against the inner wall of
the holder and thus effects its own secure guidance. The pressure of the cutting
edges upon the wood of the pencil is thus entirely taken up by the holder, and the
point cannot be broken at the dangerous places—¿.e. close up in front of the wood or
in the wood. After sharpening, the pencil can be quickly removed from the machine
by simply pushing it back.
A machine according to this invention may be as follows:-
A frame or standard carries parallel to it a slide-bar on which movably mounted:
a sliding carriage provided with a chuck, which is bored out conically and has in its
conical bore a number of projecting longitudinal ribs. The chuck is pivoted by:
means of a journal or pin in the sliding carriage and engages by means of a ring of
teeth with a toothed shaft mounted so as to be parallel to the said slide-bar. The
chuck is adapted to receive the ends of pencils of different thicknesses, and its sharp.
ribs are adapted to enter the surface of, and securely hold, a pencil inserted therein.
The pencil is also automatically and accurately centered when it hears with its
forward end in the guiding holder, with the result that a perfectly uniformly formed.
point is produced.
The front end of the pencil to be sharpened is received in the conical holder, which
is fixed to the frame of the apparatus axially in relation to the hole in the rear chuck
and is provided opposite to the milling tool with a wedge shaped slot formed by
bevelling at one side.
The disc-shaped milling tool, which is placed close to this slot, is mounted in such
a manner that its cutting edges, which are directed radially to the axis of rotation of
the disc, are situated in a plane which bounds, or is tangential to, the cone of the
pencil-point to be formed. The milling tool preferably consists of a steel ring which
has at each side a circular row of radial cutting edges and which is screwed on the
axle or boss of a crank-disc, so that when one ring of cutting edges is worn out
the other ring of cutting edges can be brought into position for use by reversing the
steel ring.
Upon the rotary axle of the milling tool there is mounted a hyperbolic toothed
wheel which gears into a hyperbolic toothed wheel on the aforesaid toothed shaft so
as, on the rotation of the milling tool, to cause, through the shaft, the rear chuck and
the pencil inserted therein to rotate preferably in a direction such that adjacent parts
of the milling tool and the pencil-point will move in opposite directions. The ratio

page_text: of the gearing should be made such that the cutting ring will revolve about twice as
fast as the pencil.
Each cutting edge in succession makes a drawing cut upon the front end of
the pencil, which moves through the slot in the front holder into the range of action
of the cutting edges.
Each cutting edge begins to cut with its upper part at the base of the point to be
formed, and the cutting edge, when the cutting ring is rotated, inoves not only
towards the end of the point, but also cuts with an increasingly deeper part, and
leaves with its lower part the end of the point, the next following cutting edge
or edges having already begun to cut at the base of the point, which is slowly revolved.
This operation is an imitation of the sharpening by means of a penknife, but pro-
duces conical points of much greater exactness of shape and in a considerably shorter
time than can be done by hand.
During the sharpening, the pencil must be pushed forwards with a gentle pressure,
for which purpose the pressure of a finger upon the sliding carriage or upon a
particular part thereof, is sufficient.
I, HEINRICH AUGUST HERMANN GUHL, of 26/29, Herrengraben, in the City of
Hamburg, Germany, Merchant, 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 :-
This invention relates to improvements in apparatus for sharpening writing and
drawing pencils-such as lead, chalk, and slate pencils-by means of a rotary cutter-
disc which is provided with a holder for the point end which is arranged close to
the cutter-disc and which has made in it a slot in which the point of the rotating
pencil is securely guided into the range of action of the cutting edges of the disc.
In proportion as the cutting edges of the disc render the point more and more conical
the point bears more and more against the inner wall of the holder and thus effects
its own secure guidance. The pressure of the cutting edges upon the wood of the
pencil is thus entirely taken up by the holder, and the point cannot be broken at the
dangerous places-i.e., close up in front of the wood or in the wood.
sharpening, the pencil can be quickly removed from the machine by simply pushing
it back.
After
An apparatus constructed in accordance with this invention is represented in the
accompanying drawings, which form part of this specification, and in which-
Figure 1 is a longitudinal elevation, partly in section, and Fig. a plan, of the
improved sharpening apparatus. Fig. 3 is a section on the line I-III Fig. 1; and
Fig. 4 a section on the line II-IV, Fig. 1. Fig. 5 is an end view, and Fig. 6 a
longitudinal section, of the chuck carrying the pencil to be sharpened. Both the
latter views are drawn on a somewhat enlarged scale. Figs. 7 and 8 are detail views
showing different positions of the cutter-disc and its cutting edges, respectively, with
relation to the pencil's point.
Similar letters refer to similar parts throughout the several views.
A frame or standard A carries parallel to it a guide-barb b, on which is movably
mounted a sliding carriage c, provided with a chuck n, which is bored out conically

page_text: The chucK IS
and has in its conical bore a number of projecting longitudinal ribs n².
pivoted by means of a journal or pin n in the sliding carriage c and engages by
means of a ring of teeth or a pinion n³ with a toothed shaft a, so mounted in the
main frame as to be parallel to the guide bar b. The chuck n is adapted to receive
the ends of pencils of different thicknesses, and its sharp ribs n² are adapted to enter
the surface of and securely hold a pencil p inserted therein. The pencil is also
automatically and accurately centered when it bears with its forward end in the
guiding-holder Is with the result that a perfectly uniform point is produced.
The front end of the pencil to be sharpened is received in the conical holder g,
which is fixed to the frame of the apparatus axially in relation to the hole in the rear
chuck n and is provided opposite to the cutter-disc h with a wedge shaped slot g³,
formed by bevelling at one side.
The cutter disc h, which is placed close to this slot g¹ is mounted in such manner
that its cutting edges h¹ which are directed radially to the axis of rotation of the
dise h, are situated in a plane which determines or is tangential to the cone of the
pencil point pl to be formed. The cutter disc h preferably consists of a steel ring
which has at each side a circular row of radial cutting edges h¹ and which is
screwed on the axle or boss of a crank disc i, so that when one ring of cutting edges
is worn out the other ring of cutting edges can be brought into position for use by
reversing the steel ring or cutter disc h, respectively.
Upon the rotary axle i¹ of the cutter disc there is mounted a skew-bevel wheel k
which gears into a skew-bevel wheel on the aforesaid toothed shaft a, so as on the
rotation of the cutter-disc h to cause, through the shaft a the rear chuck n and the
pencil p inserted therein, to rotate, preferably in a direction such that adjacent parts
of the cutter-dise h and the pencil point p' will move in opposite directions. The
ratio of the gearing should be made such that the cutter disc h will rotate about twice
as fast as the pencil p.
Each cutting edge in succession makes a drawing cut upon the front end p¹ of
the pencil p, which moves through the slot g' in the front holder into the range of
action of the cutting edges h¹.
In view. of the angular relation between the pencil and cutter-disc each of the
cutting edges h will successively make a draw cut from the outer to the inner end of
such edge, and thereby form the cone and point of the pencil as the latter is fed
toward the cutter-disc the outer end of one of the cutting edges beginning to cut
before the inner end of a preceding edge has completed its draw cut, the next
following cutting edge or edges having already begun to cut at the base of the point,
which is slowly rotated. This operation is an imitation of the sharpening by means
of a penknife, but produces conical points of much greater exactness of shape and in a
considerably shorter time than can be done by hand.
During the sharpening the pencil must be pushed forward with a gentle pressure,
for which purpose the pressure of a finger upon the sliding carriage c or upon a
particular part c' thereof is sufficient.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In a pencil-sharpening machine, a rotating cutter-disc having cutter-teeth
radiating from its axis of rotation, a pencil-holder for one end of the pencil adapted
to move toward and from said cutter-disc and to present the other end of the pencil
tangentially to the cutting-face of said dise, a fixed guide for the last-named end of
the pencil having a longitudinal wedge-shaped slot facing said cutting-face of the
cutter-disc, and means for rotating the pencil in the fixed guide or holder, controlled
by the rotation of the cutter-disc, for the purpose set forth.
2. In a pencil-sharpening machine, the combination with a cutter-disc having
cutter-teeth radiating from its axis of rotation, and having a spindle, of a toothed
shaft geared to the said spindle, a holder for one end of the pencil geared to the said
shaft, the said holder being journalled to its support, a guide on said support

page_text: having motion toward and from the cutter-disc, and a guide for the end of the pencil
to be sharpened, the said parts being arranged to present such end tangentially to the
cutting-face of said disc, for the purpose set forth.
3. In a pencil-sharpening machine, the combination with the cutter-disc having
cutter-teeth radiating from its axis of rotation, its spindle, and the toothed shaft a
geared to said spindle, of the support c, the chuck n journalled thereto and geared to
said shaft a, said chuck being provided with an inwardly-tapering axial cavity having
radially-projecting teeth and a fixed guide or holder for the end of the pencil to be
sharpened for the purpose set forth.
4. In a pencil-sharpening machine, the combination with a cutter-dise having
cutter-teeth radiating from its axis of rotation, its spindle, and the toothed shaft a
geared to said spindle to revolve at a lower rate of speed; of a holder for one end of
the pencil geared to said shaft a, a support for said holder adapted to move toward and
from the cutter-dise so as to present the end of the pencil to be sharpened
tangentially to the cutting-face of said dise, and a guide for said pencil end, for the
purpose set forth.
5. The improved apparatus for sharpening pencils, constructed arranged and
operating substantially as herein before described with reference to and shown in the
drawings annexed.
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.