A NEW OR IMPROVED MACHINE FOR FORMING SCREW THREADS
Year: 1880

page_text: LETTERS PATENT to Gerard Wenzeslaus von Nawrocki, of the Firm of
J. Brandt and G. W. v. Nawrocki, of 124, Leipzigerstrasse, Berlin, Germany,
Patent Agent, for an Invention of "A NEW OR IMPROVED MACHINE FOR
FORMING SCREW THREADS." A communication from abroad by William
Erichson, of Baltimore, in the State of Maryland, United States of America.
PROVISIONAL SPECIFICATION left by the said Gerard Wenzeslaus von
Nawrocki at the Office of the Commissioners of Patents on the 11th
September 1880.
GERARD WENZESLAUS VON NAWROCKI, of the Firm of J. Brandt and G. W. V.
Nawrocki, of 124, Leipzigerstrassć, Berlin, Germany, Patent Agent.
"A NEW
OR IMPROVED MACHINE FOR FORMING SCREW THREADS." (A communication
from abroad by William Erichson, of Baltimore, in the State of Maryland, United
States of America.)
This machine is for forming screw threads in bolts, and consists essentially of
two grooved rings or discs on shafts placed at an angle to each other and revolving
in opposite directions, the bolt being placed between them while hot, and the
thread being pressed into it by the said grooved parts.
According to one arrangement the two shafts are placed end to end at a very
obtuse angle, and one shaft a little higher than the other; at the ends of the shafts
near each other each shaft is fitted with a disc to which a ring is fastened so as to
be easily removed; the rings are grooved on the faces opposite to one another, and
the bolt being passed between them through a bush or other guide, while they
revolve at the same speed in opposite directions is carried along by them, and so as
also to turn and a screw thead formed on it.
The shafts (or one of them) are capable of being moved endways in their
bearings by toggle lever gear, or in any other suitable manner. The screw-pitch
will be greater the greater the eccentricity of the shafts.
The rings revolve in water or other cooling and lubricating liquid.
According to a modified arrangement the revolving shafts aro placed side by
side and at an angle; at the diverging end each shaft has a disc with grooves on
the circumference. The bolt is guided in between them and formed with screw
threads while being revolved. The axes of the shafts are as before not in the
same plane, so that they cannot if prolonged converge,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Gerard Wenzeslaus von Nawrocki in the Great Seal Patent Office on
the 11th March 1881.
GERARD WENZESLAUS VON NAWROCKI, of the Firm of J. Brandt & G. W. v.
A NEW
Nawrocki, of 124, Leipzigerstrasse, Berlin, Germany, Patent Agent.
OR IMPROVED MACHINE FOR FORMING SCREW THREADS." (A communication
from abroad by William Erichson, of Baltimore, in the State of Maryland, United
States of America.)
This machine is for forming screw threads in bolts, and consists essentially of
two grooved rings or discs on shafts place at an angle to each other and revolving
in opposite directions, the bolt being placed between them while hot, and the
thread being pressed into it by the said grooved parts.
According to one arrangement the two shafts are placed end to end at a very
obtuse angle, and one shaft-a-little higher than the other; at the ends of the shafts
near each other each shaft is fitted with a disc to which a ring is fastened, so as
-to-be-easily removed; the rings are grooved on the faces opposite to one another,
_and_the bolt being passed between them-through-a-bush or other guide, while
they revolve at the same-speed-in-opposite directions is carried along by them;
and so as also to turn and a screw thread formed on it. The shafts-(or-one. of
them) are capable of being moved endways in their bearings by toggle gear,
or in any other suitable manner. The screw pitch will be greater the greater the
eccentricity of the shafts. The rings revolve in water or other cooling lubricating
material.
Figure 1 of the accompanying Drawings is a side view of such a machine;
Figure 2 is a plan; Figure 3, a section through A, B, Figure 2, and Figure 4 (as
regards the lines in full) is an enlarged sectional view showing the formation of
the screw thread on a bolt.
The two discs a are of like size and are fastened on the shafts d, d¹; to each
disc a is fixed a ring b, and these latter have grooves in the faces opposite to one
another; these grooves are of the form and size of the thread required; the rings
or dies b being fastened by screws are removable, so that rings with other grooves
may be substituted as required. The shafts d, d', are placed at a very obtuse angle
to each other, as shown in Figure 2, and the centre line of the shaft d is a little
highor than that of the shaft d, as shown in Figure 1; p is a trough containing water
or other suitable cooling and lubricating liquid wherein the discs a and rings b
revolve. The shafts d, d, are in this case both capable of being moved end ways
in their bearings by means of the two pairs of toggle levers or links g, which
at their connecting joints are connected to the levers turning each on a
fulcrum hand united by a cross bar h'; m is a bush through which the bolt or
other article to be operated on while in a hot or plastic state is guided so as
to enter between the two grooved rings b; the bush is slotted at o so that the
rings 6 can act on the bolt at this place; j, j, are tooth wheels fixed on the
shafts d, d', and gearing with other tooth wheels in such manner that the
shafts d, d', receive revolving motion at equal speeds, but in opposite directions.
The bolt or other article in a hot or plastic state having been put into the guide
bush m, the discs a and rings b are made to approach each other by depressing the
cross bar h¹, so as to straighten the toggles g more or less, or sufficiently for the
rings or dies b to grip the bolt between them, thereby causing it to rotate and at
the same time to move axially, screw threads being thereby impressed in it. The
greater the vertical distance between the centre lines of the shafts d, d', the greater
will be the pitch of the screw thread, and if the distance were reduced to nothing
no screw thread would be formed, but only concentric grooves.

page_text: According to a modified arrangement the revolving shafts are placed side by side
and at an angle; at the diverging end each shaft has a disc with grooves on the
circumference. The bolt is guided in between them and formed with screw threads
while being revolved. The axes of the shafts are as before not in the same plane,
so that they cannot if prolonged converge.
The dotted lines and letters in Figure 4 indicate such an arrangement. The
shafts d, d', having their axes arranged relatively, as just described, have each a
disc b' with grooves on the circumference. The shafts are moved axially before the
bolt is placed between the discs b¹.
And having thus described and ascertained the nature of this Invention as
communicated to me, I declare that I claim,-
First. In a machine for producing screw threads on a bolt or other article while
hot or plastic, the application of two discs a placed eccentrically to each other, and
having concentric rings or dies b with grooves corresponding to the desired screw
thread, the said discs being revolved in opposite directions, so that the rings or
dies produce scrow threads on the bolt or other article placed between them, as
described and shown.
Second. In a machine for producing screw threads in a bolt or other article while
hot or plastic, the application of two discs or rollers b¹ having grooves in their
circumference corresponding to the desired screw thread, the shafts of the said discs
being mounted diverging and unlineable with each other, and capable of being
moved axially, as described and shown.
In witness whereof, I, the said Gerard Wenzeslaus von Nawrocki, have
hereunto set my hand and seal, this Eighth day of March, in the year of
our Lord One thousand eight hundred and eighty onc.
CEDARD WENZESTADIS ON NAWROCKI
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