JMPROVEMENTS IN KNURLING ATTACH- MENTS TO SCREW CUTTING MACHINES
Year: 1885

page_text: I, ALEXANDER ANDERSON, Manager of the Singer Manufacturing Company's
Works at Kilbowie, Dumbartonshire and at Glasgow, Lanarkshire do hereby
declare the nature of my invention for "JMPROVEMENTS IN KNURLING ATTACH-
MENTS TO SCREW CUTTING MACHINES," the same being a communication to me
from abroad by the Singer Manufacturing Company, of New York, in the United
States of America, Sewing Machine Manufacturers.
"
This invention has reference to an improved knurling attachment for automatic
and other screw-cutting machines of that class by which so-called "fancy screws
or screws with ornamental heads, such as are used for sewing machines and similar
purposes are made.
In the machines heretofore in use for this purpose the screws
are cut from a continuous rod of the required thickness, first, by reducing the
shank of the screw to the required thickness, then threading the shank of the
screw, then shaping the head, next knurling the circumference of the enlarged
portion of the head, and finally cutting off the finished screw from the rod.
knurling of the head was heretofore accomplished by means of a knurling die or
roller, that was pressed against the centre of the head of the screw, said die being
removed again so as to be out of the way of the cutting-off tool, by which
considerable time was lost.
The
The object of my invention is so to improve the said screw-cutting machines
that the knurling attachment is arranged on the same slide with the tools that
shape the head of the screw and cut off the screw after the knurling is completed,
the knurling die being applied to the head of the screw at the proper moment
during the forward motion of the slide piece, whereby the construction of the
screw machines is simplified and a greater number of screws finished in a given
time.
The invention consists of a knurling die or roller, that is supported in laterally
and vertically-adjustable bearings of slide piece, on which the head-shaping and
cutting-off tools are moved transversely to the wire rod from which the screws

page_text: are cut, said knurling die being located intermediately between said tools and
so as to pass below, or it might be above, the rod from which the screws are
made.
In the accompanying Drawings Figure 1 represents a side elevation of an
automatic screw cutting machine, and Figures 2, 3, and 4 are respectively a side
elevation, a plan, and an end view of a slide-piece with my improved knurling
attachment, said Figures being drawn on a larger scale.
Similar letters of reference indicate corresponding parts.
A in the drawings represents the supporting frame of an automatic screw-
cutting machine. On the frame A is a revolving turret head A¹ to which the
reducing tool and threading chuck are fastened in the usual manner.
After the wire is fed for the proper length through the hollow spindle B, the
reducing or shank-cutting tool cuts it to the proper size, after which the shank is
threaded by the threading chuck. As soon as the threading of the shank is
completed, the wire rod is acted upon successively by a shaping tool C, for forming
the head of the screw, a die D for knurling the circumference of the same, and a
cutting off tool E for separating the finished screw from the wire-rod. The tools C
and E and knurling die D are adjustably supported in transverse ways a a of a
slide piece F, which is moved in ways b of the frame A transversely to the wire
rod and actuated automatically by the lever J and cam K in the usual manner in
screw cutting machines. The head shaping tool C begins to act at the moment
when the threading of the shank has been completed. As soon as the head has
been shaped the slide-piece F is moved forward, so that the knurling die 1)
that is located intermediately between the head-shaping and cutting-off tools C
and E can be applied.
The knurling die or roller D is supported in bearings D₁ of the slide piece F,
said bearings being vertically adjustable by set screws f, f, and fixed by screws g, g,
so that the knurling die D can be set exactly to the diameter of the screw head to
be knurled. The die D is supported in its bearings D' below or above the screw-
head, so that the knurling die can pass from one side of the screw to the other, as
shown in Figure 2. By the pressure of the knurling die against the circumference
of the head and the simultaneous turning of the screw, the knurling of the rim
of the head is accomplished. As soon as the knurling operation is completed, the
slide piece F moves the cutter E against the wire rod, the cutter E cutting off the
screw, which is then dropped into a suitable receiver.
The slide-piece F is then returned and moved forward again at the proper time,.
so that the operations just described are repeated, the wire rod having been first
fed forward in the spindle B for the required distance.
The essential feature of my invention is that the knurling die D is arranged in
line with and on the same slide-piece with the head-shaping and cutting tools C
and E, so that the knurling die is applied to the heads of the screws during the
forward motion of the slide-piece F without requiring a special lateral motion for
applying the knurling die as heretofore.
In this manner the finishing of fancy screws, nuts, and other articles that require
knurling, can be quickly and automatically accomplished on the screw-cutting
machines described.
I am aware that automatic screw-cutting machines, in which the shaping tools,
parting tool and knurling tool are placed on a revolving head supported on a
cross slide have been used heretofore. In this case the first tool to operate on
the screw head is the shaping tool. When this has done its work, the slide moves
back and revolves the head, bringing the second shaping-tool into the position before
occupied by the first shaping-tool. The slide then moves forward and brings this
tool into contact with the head of the screw and when it has performed its
operation the slide moves backward again, the head revolves and brings the
knurling tool into the position formerly occupied by the shaping tools. When in
that position the slide moves forward, bringing the knurling tool into contact with

page_text: the head of the screw, pressing against the centre of the screw-head. When the
knurling has been finished the slide moves backward again and the head revolves,
bringing the parting tool into the position occupied by the shaping and knurling
tools, after which the slide moves forward again and cuts off the finished head of
the screw. These different operations consume considerable time, as they require
8 movements of the cross slide, and 4 tools to perform the same amount of work
that in my knurling attachment is performed by two movements of the cross slide
and three tools.
My knurling attachment requires no revolving head, and is considerably simpler
than the knurling devices of the screw-cutting machines heretofore in use The
tools are placed on a cross-slide, into one and the saine line, the knurling attach-
ment passing entirely under or over the head of the screw and not pressing on the
side, whereby only two movements of the cross-slide are required and the
construction of the machines considerably simplified.
This improved attachment shown in Figures 2, 3, and 4, and so far described as
applied to an automatic screw cutting machine in reference to and shown in
Figure 1, is also suitable for being worked by band in other screw cutting machines
by a simple hand lever L L' fulcrummed on a stud in a snug projecting down
from the stationary guide bed or ways b of the slide F, the vertical arm L of the
lever working the slide F by a pin f' projecting from this, and the hand lever L'
projecting outwards, as shown in dotted lines in Figures 2 and 3, enables the
slide F and to be reciprocated by hand all otherwise as herein before described.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what
I claim is
First. In screw-cutting machines, the combination, with a transversely-moving-
tool-supporting-slide, of a head-shaping tool, a cutting off tool, and a knurling die
or roller that is supported on said sliding piece interme liately between said tools,,
said sliding piece being operated either automatically or by hand substantially as
described.