Year: 1888

page_text: I, CHARLES DAKE ROGERS, of 21, Steven Street, Providence, State of Rhode Island,
United States of America, Superintendent, do hereby declare the nature of my
invention and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement :-
My invention relates to the manufacture of wood-screws having conical or cylindrical
heads with flat faces, and slots across the faces to receive the blade of a common
screw-driver. Probably more than nine tenths of the wood-screws used have these
features. As heretofore made the slots and surfaces of the heads are produced
by cutting tools which remove a considerable portion of the metal required for
the heads.
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The object of this invention, in connection with some others for which I have made
application for patents, is to produce a stronger head, at less cost for labor and
material than has heretofore been done, and at the same time preserve the essential
features as to form and manner of use of screw-heads as heretofore made.
The saving of labor and material I secure by substituting a process of forging to
produce the required forms and slots for the operations of shaving and nicking, so
called, as heretofore practiced. The increased strength I secure by preserving the
forged surface of the head, or the "skin" of the metal, formed against the surface of
the die in swaging or forging, and by an unbroken contour of the conical or cylindrical
surface of a screw-head.
In an application filed by me upon even date herewith, I have described a machine
for making finished screw-heads by forging the heads in a solid die.
I make the slot of the ordinary form except that the ends are closed by a web of the
metal sufficiently thick to substantially strengthen the head against the torsional strain
of a screw-driver, but not thick enough to reduce the width of the blade of a screw-
driver which may be used sufficiently to impair its efficiency in turning the screw. In
this way the conical or cylindrical surface of a screw-head is made continuous and a
resistance is furnished, at the ends of the slot to the strain of a screw-driver. The
common screws heretofore made with slots extending completely across the head have
a tendency to fail, especially if made of steel, either by splitting in the line of the slo

page_text: or by breaking off one side of the head at the bottom of the slot. The metal which I
leave at the ends of the slot acts as an effectual stay to counteract this tendency. In
the use of crystalline or non-fibrous iron or steel it is important to avoid sharp entering
angles or corners in the metal from which cracks or breaks may be easily extended
under moderate strains. I therefore make the ends of the slots round or oval. This 5
not only reduces the liability to breaking, but it facilitates the flow of the metal under
pressure of the hammer which upsets the metal in the die.
In the drawings hereto annexed-
Fig. 1 is a sectional view taken through the center of a die having a slotted headed
screw-blank therein. Fig. 2 is a top view of the screw-head. Fig. 3 is a perspective
view of the slot-forming hammer or punch. Fig. 4 is an inverted end view thereof.
Fig. 5 is a vertical central sectional view of a screw-head having a rectangular
pyramidal slot formed therein for the reception of a driver. Fig. 6 is a similar sectional
view taken transversely of the slot. Fig. 7 is a plan view of the head. Fig. 8 is a
perspective view of the end of a driver adapted to engage the slot.
Many attempts have been made to provide a substitute for the common slot across
the face of a screw as a means for the insertion of the screw into wood, but none of
them have come into. use, mainly, I believe, because they either weakened the head
of the screw or involved the use of some other instrument than a screw-driver of the
common form.
An instance of this is shown in a patent granted in the United States to J. Frcarson,
Dec. 9th, 1873; No. 145,411. A peculiar recess is described in that patent for the
use of a peculiar screw driver. In its most simple form it is represented in the drawings
hereto annexed by Figs. 5, 6 and 7 (the driver being shown in Fig. 8). They show
a cavity e formed in the head c of a screw which is rectangular at the face of the
head, but which terminates in a point at the axis of the screw. It requires a screw-
driver with a blade forming a rectangular pyramid, as e¹, and its sharp angles expose
the screw-head to destruction by the strain required to insert it in the wood. The
screw is, I believe, of no practical value. In making it a pointed blade or punch is
forced into the metal cutting its way at the point and spreading the metal from its
four sides like a wedge.
In making the slot, a, which I have described as a feature of my improved screw, a
punch with substantially parallel sides and a flat and nearly rectangular face is
forced into the metal, compelling it to flow away from the face of the punch as it
advances.
d indicates a solid die having a conical-shaped cavity in its upper face, forming the
counterpart of the screw-head h, Fig. 1. The head has a slot a across its face, closed
at the ends, adapted to receive the blade of an ordinary screw-driver.
By means of this construction the head, as before stated, is materially strengthened
and adapted to withstand the strain of the screw driver without injury.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
A wood-screw with a flat-faced head formed by forging in a solid die and having a
slot across the face, with walls or sides vertical, or nearly so, and closed at the ends,
and so adapted to receive the blade of an ordinary screw driver to force the screw into
the wood.