An Improvement or Improvements in the Manufacture of Screws.
Year: 1889

page_text: Date of Application, 13th Nov., 1889
Complete Specification Left, 31st July, 1890-Accepted, 6th Sept., 1890
PROVISIONAL SPECIFICATION.
An Improvement or Improvements in the Manufacture of Screws.
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:-
In that method of manufacturing screws in which the screw thread is formed by
the pressure of a tool or a roll or rolls on an ordinary screw blank no metal being cut
away the screw thread formed is of greater diameter than the blank on which it has
been made the pressure by which the metal is displaced to form the trough of the
screw thread forcing the said displaced metal outwards or radially thereby forming a
screw thread the crest or summit of which is of greater diameter than the blank on
which it has been formed.
In consequence of the extreme diameter of the screw thread in screws manufactured
as described exceeding the diameter of the portion of the blank on which no screw
thread has been inade the said screws are inferior to screws in which the diameter of
the screw thread is the same as or does not exceed that of the unthreaded portion of
the finished screw.
The object of our invention is to remedy the defect referred to and consists in the
manufacture of screws of an improved character by the process or combination of
processes hereinafter described. By means of the said process or processes "pressure
inade screws can be manufactured the threads of which do not exceed in diameter
that portion of the screw which has no screw thread made upon it.
In making a screw according to our invention we take a screw blank having a
shank of uniform thickness and of length sufficient to provide for the rolling of the
screw as hereinafter described we reduce the diameter of that part on which the screw
thread is to be made. This reduction wo effect preferably by a drawing process
that portion of the cylindrical body of the blank on which no screw thread is to be
formed being left unreduced in diameter.
The blank prepared as described is subjected to the action of the pressing mechanism
by which the screw thread is to be formed, the arrangement of the said mechanism
being such that it operates only on the part of the blank of reduced diameter. By
the action of the said mechanism a screw thread is formed the machinery being so
arranged that the said thread is of a diameter not exceeding that of the part of the
finished screw on which no screw thread is formed. The extent to which the diameter
of that part of the blank on which the screw thread is to be formed is reduced depends
upon the depth of the screw thread to be made.
The machines we employ in conducting the processes constituting our invention are
such as are commonly used for like purposes.
Instead of reducing the diameter of that part of the blank on which the screw
thread is to be formed by the process of drawing, it may be reduced by rolling or
turning.
Dated this 18th day of November 1889.
W. T. WHITEMAN,
Agent for the Applicants.

page_text: COMPLETE SPECIFICATION.
An Improvement or Improvements in the Manufacture of Screws.
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 and the
manner in which the same is to be performed to be particularly described and ascertained
in and by the following statement :—
In that method of manufacturing screws in which the screw thread is formed by
the pressure of a tool or a roll or rolls on an ordinary screw blank no metal being cut
away, the screw thread formed is of greater diameter than the blank on which it has
been made the pressure by which the metal is displaced to form the trough of the
screw thread forcing the said displaced metal outwards or radially thereby forming a
screw thread the crest or summit of which is of greater diameter than the blank on
which it has been formed.
In consequence of the extreme diameter of the screw thread in screws manufactured
as described exceeding the diameter of the portion of the blank on which no screw
thread has been made the said screws are inferior to screws in which the diameter of
the screw thread is the same as or does not exceed that of the unthreaded portion of
the finished screw.
The object of our invention is to remedy the defect referred to and consists in the
manufacture of screws of an improved character by the process or combination of
processes hereinafter described. By means of the said process or processes pressure
made screws can be manufactured the threads of which do not exceed in diameter
that portion of the screw which has no screw thread made upon it.
In making a screw according to our invention we take a screw blank having a
shank of uniform thickness and of a length sufficient to provide for the rolling of the
screw as hereinafter described.
We reduce the diameter of that part on which the screw thread is to be made.
This reduction we effect preferably by a drawing process that portion of the cylindrical
body of the blank on which no screw thread is to be formed being left unreduced in
diameter.
The blank prepared as described is subjected to the action of the pressing mechanism
by which the screw thread is to be formed the arrangement of the said mechanism
being such that it operates only on the part of the blank of reduced diameter. By
the action of the said mechanism a screw thread is formed the machinery being so
arranged that the said throad is of a diameter not exceeding that of the part of the
finished screw on which no scrow thread is formed. The extent to which the diameter
of that part of the blank on which the screw thread is to be formed is reduced depends
upon the depth of the scrow thread to be made.
The machines we employ in conducting the processes constituting our invention are
such as are commonly used for liko purposes.
Figure 1 of the accompanying drawing represents in elevation and cross section
the headed and nicked screw blank before its shank has been elongated and partly
reduced in diameter; Figure 2 represents the said screw blank after a portion of it
has been reduced in diameter and the screw blank elongated ready for the worming
operation and Figure 3 represents a finished screw made from the prepared screw
blank Figure 2, the worm or thread a of the said screw being made by pressure from
the reduced part 6 of the shank of the screw blank Figure 2 the threaded or worm
part a of the screw having about the same or not exceeding the diameter of the
unreduced part c of the shank of the finished screw which part c has not been
screwed.
In making the screw Figure 3 we take the headed and nicked blank Figure 1 and
preferably by a drawing process we reduce the diameter of a portion of the shank of
the screw blank as represented at 6 Figure 2 leaving the part e nearest the head

page_text: unreduced or unoperated upon. The reduced and elongated part 6 of the shank is
then wormed or threaded by pressure effected by dies or a roll or rolls so as to
produce the screw represented at Figure 3 the threaded part a having about the
same diameter as or not exceeding the diameter of the unscrewed part c of the
screw.
The machines which we employ in conducting the process constituting our invention
are such as are commonly used for like purposes, but the screw blanks may be
conveniently reduced in diameter by the use of the machinery patented by one of us
namely the said John Sheldon on the 1st day of June 1889 No. 9112 but we do not
limit ourselves to the use of that reducing machinery and instead of reducing the
dinmeter of that part of the shank of the blank on which the screw thread is to be
formed by the process of drawing it may be reduced by rolling or turning.
Having now particularly described and ascertained the nature of our inven-
tion and the manner in which the same is to be performed we declare that we
claim as our invention of "An improvement or improvements in the manufacture
of screws
"
Manufacturing screws threaded or wormed by pressure by the process or combination
of processes herein before described and illustrated in the accompanying drawing; that
is to say, taking a screw blank and reducing the diameter of that portion of its shank
on which a screw thread is to be formed leaving a portion near the head on which no
screw thread is to be formed unreduced in diameter and by the operation of pressing
mechanism worming or threading the part of the blank of reduced diameter thereby
forming a screw the wormed or screwed part of which is of a diameter about or not
exceeding that of the part of the finished screw on which no screw thread is formed
substantially as described and illustrated.
Tol
TL 1000
HUGH NETTLEFOLD.
JOHN SHELDON.