Improvements in Propeller Pencils.
Year: 1894

page_text: Date of Application, 11th Sept., 1894-Accepted, 13th Oct., 1894
COMPLETE SPECIFICATION.
Improvements in Propeller Pencils.
I, BENJAMIN WILLCOX of 47 Lincoln's Inn Fields in the County of Middlesex
Patent Agent do hereby declare the nature of this invention (which has been
communicated to me by The Eagle Pencil Company of the City County and State
of New York United States of America) 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 what are known as propeller pencils, and it consists of
certain novel structural features which I will describe with reference to the
accompanying drawings.
Figure 1 is a longitudinal central section of a pencil embodying this invention.
Figures 2, 3, 4 and 5 are perspective views of the four parts of the propeller
movement, viz. the lead tube (Figure 2) the propeller screw (Figure 3) the follower
(Figure 4) and the driving thimble (Figure 5).
Figure 6 is a cross-section of the lead-tube, the section being taken on the
line 6-6 Figure 2, and
Figure 7, is a view of the sheet metal blank, from which the lead tube is formed.
The lead-tube A which is made of sheet metal has a front cylindrical portion a,
of the size of the lead to be contained therein the lead fitting snugly in this portion
of the tube. Back of the front portion a, the tube becomes approximately elliptical
in shape as seen at b, Figure 6, having on one side an enlargement b', extending
lengthwise of the tube for the remainder of its length, which enlargement is a
channel for the reception of the propelling screw B. At the front end of the
enlargement is a hole c through which the front end of the screw passes, and in
which it takes its bearing. At the rear of the enlargement is a slot e which
is entered and engaged by an annular collar d on the screw; and back of the slot
are lips or flanges d', which after the screw is put in place are bent over, so
as to surround the shank of the screw back of the collar d, thus giving the screw a
rear bearing and holding it in position in the lead tube.
The blank from which the lead tube is formed is shewn in Figure 7. The part a
of the tube is formed by the fingers a¹ and the main body of the tube by the
part the slot e and flanges d' of Figure 2 are marked with the same reference
letters in Figure 7. This blank by suitable shaping tools is bent up into the form
shewn in Figure 2, the fingers a¹ being bent each into the shape of a half round in
cross section, and after the screw is inserted in place the lips or flanges d¹ are bent
towards each other so as to surround the shank of the screw back of its collar d.
In this economical and expeditious way the parts are made and fitted and held
together without brazing or the use of any extraneous fastening devices.
The follower is shewn at C. It is provided with a tubular-screw threaded
portion, projecting laterally from the body of the follower into the enlargement b,
and encircling and engaging the screw B. Rotation of the screw will advance or
retreat the follower, according to the direction of rotation.
The pencil case or sheath consists of the front and rear sections D D'. The
front section D is mounted on, and secured to a sleeve i. Within this sleeve fits
and is held another sleeve j. swivelled to the sleeve i, so that the one may rotate
independently of the other. The sleevej for this purpose having in it an annular
The
groove entered by an annular internal rib on the outer sleeve i
sleeve projects to the rear of the sleeve i and on it is fitted and secured the

page_text: rear section D¹.
Thus the one part of the handle can rotate independently
of the other. The lead tube A and the propeller movenient carried by it
are attached to the front handle section D. The tube A for this purpose
passes through a head (Figure 1) with which the sleeve i is provided and is
restrained from longitudinal movement therein by two fins x. (Figures 1, 2 and 7)
formed by appropriately slitting one of the edges of the blank as shewn at x
(Figure 7). The rear fin is turned up before the lead tube is inserted from the
rear into the lead tube and when this fin brings up against the interior of the
head, the front, and now exterior fin is turned up, these parts then occupying
the position shewn in Figure 1.
Provision is made for rotating the propeller screw by connecting it to that
portion of the handle which can rotate independently of the part in which the
propeller movement is mounted and held. The connection is made as follows: The
screw at its rear has a flat stem g, which enters a slot h¹ in the head of a driving
thimble h, which fits and is held in the part D' of. the handle. But there is no
rigid connection between this thimble and the part of the handle in which it is
mounted. On the contrary the thimble, which ordinarily rotates with the
part D. yet is nevertheless capable under certain circumstances that is to say,
when the resistance to rotation of the screw exceeds a predetermined limit of
rotating independently of said part D¹ this result being attained by means of a
friction joint between the two. The propeller C at each extreme of its movement
comes against a rigid abutment, and if after this point is reached, the screw, as not
infrequently is the case, is by inadvertence or carelessness still further rotated in the
same direction, some part of the propeller movement usually the joint between the
propeller and the screw would give or break, thus unfitting the pencil for further
use, but the friction joint between the driving thimble and the part D' prevents
such breaking. The thimble rotates with the part D₁ so long as conditions are
normal, but the moment there is obstruction to further movement of either the
screw or the propeller, the friction joint permits the handle to rotate, while the
driving thimble remains at rest. The friction joint is readily provided by slitting
longitudinally the thimble (which is made of sheet brass) so as to provide it with
a series of outwardly expanding spring fingers which bear against the interior of
the part D¹ for rotating the thimble, with sufficient force to cause the thimble
to follow the movement of the handle until an obstruction is met as hereinbefore
explained.
Having now particularly described and ascertained the nature of this said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
-
e
1. In or for a propeller pencil the lead tube A formed from a sheet metal blank,
having fingers a to form the front cylindrical portion a of the tube, a body portion
to form the elliptical part of the tube, a slot è and lips or flanges d' in combination
with the propeller screw contained in the enlargement 61 of the elliptical part of
the tube provided with a collar d, to engage the slot e and having its shank back
of the said collar surrounded by the lips or flanges das and for the purposes
herein before described and illustrated in the accompanying drawings.
2. In or for a propeller pencil the lead-tube A formed as described with a
cylindrical part a, an enlarged elliptical part b, a slot e and lips d', the propeller
screw contained in the said enlarged part of the tube having a collar d to engage
the slot e, and clasped back of the said collar by the lips d³, a handle composed of
two independently rotatable parts the one carrying the lead tube, and a driving
thimble frictionally held in the other part and engaging the propeller screw, these
parts being combined and arranged as herein before described and illustrated by
the accompanying drawings.
3. In a propeller pencil, the combination with the case or handle, having an
independently rotatable part, of a lead tube, and lead propelling screw and follower

page_text: mounted in and secured to the handle, and a driving thimble connected to the
propeller screw and frictionally mounted and held in the rotatable part as and for
the purposes hereinbefore described.
Dated this 11th day of September 1894.
JOHNSONS & WILLCOX,
Agents.