HAMMERS FOR FORMING THE HEADS OF SCREWS
Year: 1888

page_text: I CHARLES DAKE ROGERS, of Providence, in the County of Providence, and State
of Rhode Island, United States of America, Mechanic, do hereby declare the nature
of my invention for HAMMERS FOR FORMING THE HEADS OF SCREWS 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 Improvements in Heading Hammers employed in forming
the heads of Screws.
In an application for patent filed simultaneously herewith, No. 12,734 I have
described a method for making finished heads for Screws by forging alone, and
in another application filed by me July 10th, 1888, No. 10,039 I have described a
machine employing three hammers for forming screw heads which is adapted
especially to forging heads of a larger diameter relatively to the wire from which
they are forged than has heretofore commonly been done.
In the process described in the first application the slot in the head of a screw
is formed by a tongue extending from the face of the hammer which finishes the
head. This tongue is forced into the metal in advance of the action of the flat
surface of the hammer upon the metal and forms an obstacle to the flow of the
metal from one side of the die to the other. It
important therefore that the
metal, before this hammer acts upon it, shall be distributed symmetrically with
reference to the slot upon the two sides of the die.
Again, it is obvious that the tongue, as it is forced into the metal, must spread the
metal laterally, but at the ends of the tongue it does not force the metal freely
towards the conical surface of the die but has a tendency to carry it downward so as
to produce an imperfect face at the ends of the slot. This tendency shows itself most
decidedly in making heads of a larger diameter across the face than has been com-
monly practiced heretofore and must be met by securing a proper distribution of the
metal in the die before the hammer acts upon it, and these requirements must be
provided for in one or more of the hammers which are brought into action before the
Gnishing hammer.

page_text: To attain these requirements, is the objects of the present invention, illustrated in
the accompanying two sheets of drawings, in which Figure 1, is a perspective view,
representing a screw head having the nick extending entirely across its face as usual.
Fig. 2 is a similar view of a screw head in which the slot is closed at each end.
Fig. is a perspective view of a screw head showing the tendency of the metal to he
forced downward at the ends of the slot by means of the tongue of the nick-swaging
hammer, as referred to in the preceding paragraph. Fig. 4 is a vertical sectional viow
taken through the center of the die and the lower portion of the first heading hammer,
and also showing a wire in position to be upset. Fig. 5 is a similar sectional view
showing the metal upset, thereby producing a symmetrical preliminary head. Fig. 6
is a perspective view showing a concave groove extending across the face of the
second hammer. Fig. 7 is a transverse sectional view thereof taken through its
center. Fig. 8 is a vertical central sectional view of the die and a second hammer,
showing the upper face of the head of the blank made somewhat rounded and con-
forming to the shape of the hammer face. Fig. 9 is a similar view of the parts,
viewed at right angles to the former position. Fig. 10, sheet 2, is a perspective view
showing the working face of the third or slotting hammer. Fig. 11 is a vertical
central sectional view of the hammer. Fig. 12 is a perspective view of another form
of the second hammer, showing a convex or cylindrical projection extending partially
across its face in lieu of the concave groove shown in Fig. 6; and Fig. 13 is a
sectional view, corresponding to Fig. 8, showing the hammer represented in Fig. 12
impressed into the metal and disposing the same immediately preceding the action
of the slotting hammer.
The following is a detailed description of my improvement in the manufacture of
wood-screws.
I would state, that the finished screw head a', represented in Fig. 2, is constructed
in accordance with my present invention, while the head a², shown in Fig. 3,
represents an effect which may be produced by hammers unprovided with such
improvement, wherein the metal fails to properly fill the cavity of the stationary die,
thus forming the indentations, or depressions, d, at the ends of the slot.
In the several Figs. the form of the die cavity is represented conical, as at c.
A indicates the die block itself.
The first hammer 1, that I employ does not differ in construction or in its action
from that heretofore employed in the first operation of forging heads in a die with
two hammers only, as commonly used. The face of the hammer has in it a conical
cavity e terminating at its upper end in a cylindrical portion into which the end of
the wire b, enters as the hammer approaches it, see Fig. 4, the wire at the same time
being firmly clamped in position. This cavity furnishes a lateral support to the end of
the wire and prevents it from bending out of its axial line. The manner in
which it upsets the metal and partially fills the die cavity c is shown in Fig. 5.
The upset metal of the wire being indicated by 1. By this operation the metal is
symmetrically arranged, with reference to the surface of the die, and leaving an
unfilled space c¹.
But in the operation of the second hammer, i, where three are used, and a slot is
to be formed, it is necessary that the metal of the head shall be disposed symmetrically
on the two sides of the line where the slot is to be formed, and at the same time
provision must be made to fill the die at the ends of the slot. The danger of an
unsymmetrical disposition of the metal in the die increases as the diameter of the
face of the head increases relatively to the diameter of the wire, and the object I have
in view is to counteract this tendency. The best form which I have found to effect
these objects is shown in Figs. 6 and 7, wherein I have represented the second
hammer i, having a concave depression m cut across its face.
Figs. 8 and 9 represent views cut, respectively, transversely and longitudinally, of
the concave depression of said second hammer, and also showing, at 6², the corre-
sponding form of the head. It will be observed, referring to Fig. 8, that a space c²,
is left unfilled by the metal at opposite sides of the die, but are nearly filled in the
line of the depression, as in Fig. 9, which coincides with the axis of the slot when the

page_text: latter is formed. The third, or slot-forming and finishing hammer is indicated by s,
Figs. 10 and 11, its flat face having a tongue t, projecting from it adapted to form
the slot or nick in the head of the blank, and producing the slotted and finished head a¹
shown in Fig. 2.
The concave depression m of the second hammer when acting on the metal allows
it to flow more freely towards the ends of the depression than across it, and thus
ensures the necessary amount of metal at the ends of the tongue which in the
succeeding hammer forms the slot. The concave surface also tends to check
tendency the metal may have to flow to one side of the line in which the slot is to be
formed rather than to the other, and thus secures as far as required the symmetrical
distribution of the metal on the two sides of such line.
any
Another form which may be given to the face of the second hammer i, is represented
in Figs. 12 and 13. Practically, however, I prefer the form shown in Figs. 6 and 7.
The former differs from that shown in the latter Figs. in having a rounded projection ?
extending across a portion of the face of the hammer at right angles with the line in
which the slot is to be formed, instead of a depression on the line of the slot, but like
that it has these features in common, that the metal is symmetrically arranged with
reference to the line of the slot and it provides for the necessary amount of metal at
the ends of the tongue t, which in the succeeding hammer forms the slot. The surface
of the convex projection across the line of the slot acts in a manner analogous to a
concave surface in the line of the slot to secure the condition required to enable the
succeeding hammer to form the slot and finish the head.
The depth or width of the concave depression required will vary with the size of
the heads and the depth and width of the slot, according to the character of the metal
operated on, and can be most easily determined as to any particular screw head by
trial, and the same is true of the convex surface when that is used.
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 :-
1. The heading hammer for preparing the head of a blank for the action of a
finishing and slotting hammer, the acting part of the face of which is slightly curved
or cylindrical, substantially as herein described.
2. The combination, in a machine for forming finished heads of flat headed screws
including the slot, of two heading hammers, the first to act of which has a curved
or cylindrical surface across its face as herein described, and the second of which
is provided with a tongue extending from its face the counterpart of the slot to
be produced.
D1: J……. Ր
han 100e
Dated this fth day of September 188s.
CHARLES DAKE ROGERS,
Inventor.
Hughes, Eli & Hughes,
76, Chancery Lane, Loudon, W.C.,
Agents for the Applicant.