provements in the Manufacture of Screw Blanks.
Year: 1889

page_text: Date of Application, 7th Oct., 1889
Complete Specification Left, 25th June, 1890-Accepted, 26th July, 1890
PROVISIONAL SPECIFICATION
Improvements in the Manufacture of Screw Blanks.
We HUGH NETTLEFOLD of Hallfield Birmingham in the County of Warwick
Mechanical Engineer and JOHN SHELDON of No. 10 St. Augustine's Road Birmingham
aforesaid Mechanical Engineer do hereby declare the nature of this Invention to be as
follows:-
Our invention has reference to the manufacture of screw blanks to be made into
screws in the heads of which grooves or depressions are made for the reception of a
screw driver in place of the ordinary nick the said grooves extending diametrically
nearly but not quite all across the head. That is the said grooves are closed at their
ends instead of opening in the under conical side of the head as the ordinary
nick does.
In making a closed groove in the flat face of the head of a screw blank the
impressing tool or grooving punch on entering the said flat face of the head tends
while being depressed into the head to force the metal out on either side of it thus
distorting the circular figure of the said flat face and leaving a depression or deficiency
of metal at the ends of the groove and also leaving the sides of the groove rounded.
Our invention has for its object to produce the said closed groove without distorting
the head and without leaving a deficiency of metal at the ends and side edges of the
groove and this we effect in the following manner.
In upsetting the end of the wire of which the blank is made in order to make the
head of the blank we employ a movable or upper die or tool having two curved or
crescent shaped depressions made in its under or acting face the said depressions
being of somewhat shorter radius than the circular head of the blank to be made and
symmetrically situated at opposite sides of the centre of the tool. We also make slight
parallel depressions at a distance apart somewhat greater than the breadth of the groove
to be made the said parallel depressions being in a direction crossing a plane midway
between the crescent shaped depressions. By the operation of this die or tool in
conjunction with the lower or fixed die or tool a head is produced on the end of the
wire on the otherwise flat face of which head are two curved or crescent shaped ribs
or projections and also the two parallel projections referred to the counterparts of the
depressions in the movable tool hereinbefore described. The head thus produced is
operated upon by the impressing tool or grooving punch in such a way that the
groove made is in a line crossing the centre of the face of the head and bisecting
each of the curved or crescent shaped ribs or projections. The distortion of the
circular figure of the face of the head is thus prevented and deficiency of metal at the
ends of the groove avoided for while the metal spreads outwards at each of the longer
sides of the tool the crescent shaped ribs or projections are crushed or flattened by
the flat face of the tool and forced towards the ends of the closed groove in course of
formation.
The parallel ribs on either side of the groove are also flattened and the rounding
of the edges of the groove prevented. There is thus formed a head the top or flat face
of which is circular but somewhat larger than the said face before the grooving tool
operated upon it the said head having a closed groove crossing the centre of
its face.
Although we prefer to make the projections on the face of the head of a crescent

page_text: shape as described we do not confine ourselves thereto the essence of our invention
consisting in making projections which when the grooving tool enters the flat face of
the head will be flattened and made to prevent any deficiency of metal at the ends or
sides of the closed groove formed the flat part of the head being at the same time
preserved of a circular figure.
Dated thin 7th dow of Ontahan 1940
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Screw Blanks.
We HUGH NETTLEFOLD of Hallfield, Birmingham in the County of Warwick
Mechanical Engineer and JOHN SHELDON of No. 10 St. Augustines Road Birmingham
aforesaid Mechanical Engineer do hereby declare the nature of our Invention and the
manner in which the same is to be performed to be particularly described and
ascertained in and by the following statement:-
Our invention has reference to the manufacture of screw blanks to be made into
screws in the heads of which grooves or depressions are made for the reception of
a screw driver in place of the ordinary neck; the said grooves extending diametrically
nearly but not quite all across the head. That is the said grooves are closed at their
ends instead of opening in the under conical side of the head as the ordinary nick
does.
In making a closed groove in the flat face of the head of a screw blank the
impressing tool or grooving punch on entering the said flat face of the head tends while
being depressed into the head to force the metal out on either side of it thus distorting
the circular figure of the said flat face and leaving a depression or deficiency of metal
at the ends of the groove and also leaving the sides of the groove rounded.
Our invention has for its object to produce the said closed groove without distorting
the head and without leaving a deficiency of metal at the ends and side edges of the
groove, and this we effect in the following manner.
In upsetting the end of the wire of which the blank is made in order to make the
head of the blank we employ a movable or upper die or tool having two curved or
crescent shaped depressions made in its under or acting face, the said depressions
being of somewhat shorter radius than the circular head of the blank to be made
and symmetrically situated at opposite sides of the centre of the tool. We also make
slight parallel depressions at a distance apart some what greater than the breadth of
the groove to be made, the said parallel depressions being in a direction crossing
a plane midway between the crescent shaped depressions. By the operation
of this die or tool in conjunction with the lower or fixed die or tool, a head
is produced on the end of a wire on the otherwise flat face of which head are two
curved or crescent shaped ribs or projections and also the two parallel projections
referred to, the counterparts of the depressions in the movable tool hereinbefore
described. The head thus produced is operated upon by the impressing tool or
grooving punch in such a way that the groove made is in a line crossing the.
centre of the face of the head and bisecting each of the curved or crescent shaped
ribs or projections. The distortion of the circular figure of the face of the head is
thus prevented and deficiency of metal at the ends of the groove avoided; for while
the metal spreads outwards at each of the longer sides of the tool the crescent shaped
ribs or projections are crushed or flattened by the flat face of the tool and forced
towards the ends of the closed groove in course of forination. The parallel ribs
on either side of the groove are also flattened and the rounding of the edges of
the groove prevented. There is thus formed a head the top or flat face of which
is circular but somewhat larger than the said face before the grooving tool operated
upon it; the said head having a closed groove crossing the centre of its face..
Although we prefer to make the projections on the face of the head of a crescent

page_text: shape as described we do not confine ourselves there to the essence of our invention
consisting in making projections which when the grooving tool enters the flat face of
the head will be flattened and made to prevent any deficiency of metal at the ends or
sides of the closed groove formed, the flat part of the head being at the same
time preserved of a circular figure.
We will now proceed to describe with reference to the accompanying Drawings
the manner in which our invention is to be performed.
Figure 1 represents the cut off and pointed piece of wire from which the screw
blank is to be made; Figure 2 represents the piece of wire Figure 1 after a
bulbous projection a has been formed on the end of the blank from which end the
head is to be made; Figure 3 represents in elevation and Figure 4 in plan the
screw blank after the first heading stage by which a small head is made on its end
and the face of the partly made head provided with two crescent shaped ribs or
projections having the curvature represented and also two parallel ribs or pro-
jections cc at a distance apart somewhat greater than the breadth of the closed groove
to be made, the said parallel ribs or projections cc having the positions with
respect to the crescent shaped ribs or projections bb represented in the Drawing:
Figures 5 and 6 represent sections taken at right angles to one another of the
head part of the blank Figures 3 and 4. Figures 7 and 8 represent elevations with
the head part in section taken in planes at right angles to one another and Figure 9
in plan a finished scrow blank made from the blank Figures 3. 4. 5 and 6, the
head of the screw blank Figures 7. 8. and 9 being provided with a closed groove d
in its flat face.
Figures 10. 11 and 12 represent the upper tools used for upsetting the wire and
for impressing and grooving the head the said upper tools being used in conjunction
with the single lower tool represented in Figure 13.
The upper tool Figure 10 is first used with the lower tool Figure 13 for upsetting
the wire and forming the bulbous projection a near the end of the wire as represented
in Figure 2. The upper tool Figure 11 is used in conjunction with the lower tool
Figure 13 for further upsetting the wire and forming the crescent shaped ribs or
projections, and the parallel ribs or projections c c on the face of the head; the
upper tool Figure 11 is represented in section and plan the two sections being taken
in planes at right angles to one another. The tool Figure 11 has in its underface the
depressions f, f for forming the crescent shaped ribs or projections b, b and the parallel
depressions g, g for forming the parallel ribs or projections c, c on the face of the
head.
The upper tool Figure 12 is used in conjunction with the lower too! Figure 13 for
impressing or forming the closed groove d in the head of the blank the punch part h
of the tool entering the face of the head. In Figure 12 sectional views and plans of
the head are shown the two sectional views being taken in planes at right angles to
one another.
The finished screw blank and the same in its different stages as well as the tools
used are drawn to a large scale for the purpose of the better illustrating our
invention.
We will now describe in detail the manufacture of a screw blank with a closed groove
in its head according to our invention.
We take the cut off and pointed wire Figure 1 and place it in the lower tool e
Figure 13 and by the operation of the cupped upsetting tool Figure 10 we partly
upset one end of the wire and form the bulbous projection a on it as represented in
Figure 2. This upsetting stage of the manufacture constitutes no part of our inven-
tion. The partly upset wire of the kind represented in Figure 2 in the die Figure 13
is next operated upon by the upsetting and impressing tool represented in Figure 11
whereby a head of the kind represented in Figures 3. 4. 5 and 6 is formed upon it the
said head partly filling the conical cavity i in the lower tool e Figure 13 and the face
of the head being impressed with the crescent shaped ribs or projections bb and
parallel ribs or projections c, c the counterparts of the depressions f, ƒ and g g in the
tool Figure 11.

page_text: The partly headed blank of the kind represented in Figures 3. 4. 5 and 6 in the die
Figure 13, is finally operated upon by the impressing tool or grooving punch
Figure 12, the part of the said tool or punch Figure 12 operating upon the face of
the head in a line midway between the parallel ribs or projections c, c and partly
bisecting each of the crescent shaped ribs or projections b, b.
By the use of the crescent shaped ribs or projections b, band parallel ribs or pro-
jections c, c the distortion of the circular figure of the head is prevented and deficiency
of metal at the ends and sides of the closed groove d avoided as during the last
described stage of the heating operation while the metal spreads outwards at each of
the larger sides of the heading tool Figure 12 the crescent shaped ribs or projections b, b
are crushed or flattened by the flat face of the tool and forced towards the ends of the
closed groove in course of formation, the parallel ribs or projections ce being at the
same time flattened and the rounding of the edges of the closed groove prevented.
In place of the crescent shaped ribs or projections b, b ribs or projections of other
forms may be employed.
We are aware that it has been previously proposed in the manufacture of screws of
the kind above mentioned to so distribute the metal as to fill up depressions or
deficiencies of metal which might be caused by the action of the grooving punch and
we make no claim at large to such mode of manufacture.
Having now particularly described and ascertained the nature of our inven-
tion and in what manner the same is to be performed we declare that what we
claim as our invention of "Improvements in the manufacture of screw blanks having
heads with closed grooves :-
Forming on the face of the partly made head of the blank during the heading
operation, ribs or projections near the parts where the ends of the closed groove are to
be formed and also parallel ribs or projections situated at opposite sides of the centre
of the head and in the same direction as the intended groove, the said ribs or projections
when the grooving tool enters the flat face of the head being flattened and made to
prevent any deficiency of metal at the ends and side edges of the closed groove and
preserving the circular figure of the head substantially as hereinbefore described and
illustrated in the accompanying Drawings.
Dated the 13th day of June 1890.
HUGH NETTLEFOLD.
JOHN SHELDON.