Improvements in or relating to Screw Cutting Lathes or Machines.
Year: 1897

page_text: Date of Application, 25th June, 1897-Accepted 14th Aug!,
1897-
COMPLETE SPECIFICATION..
Improvements in or relating to Screw Cutting Lathes or Machines.
I, JEAN BAEIINI-RONGET, of the firm of Baehui & Co., of Biel, in the Republic
of Switzerland, do hereby declare the nature of this invention and in what manner
the same is to be performed to be particularly described and ascertained in and
by the following statement:-
This invention relates to a cutter-holder, which can be advantageously fitted
to any screw-cutting machine and allows of cutting the screw during the forward
and back movement of the carriage. An example of the construction of such
holder is shown in the annexed drawing in Figs. 1 to 4 and consists of a double
armed support A on which two clamps for fixing the cutting steels are arranged
it being fitted in an appropriate manner on the carriage B of the screw-cutting
machine.
S is the screw to be provided with threads, C is the clamp for receiving the
steel e which clamp is displaceable on the arm 6 of the support, A and D is a second
clamp for receiving the steel d. The steels c and d are so adjusted that they stand
with their edges opposite one another the blank to be provided with threads being
between both.
The holder C can be displaced on the arm 6 rectangularly to the axis of the
screw S and can be fixed by means of a set screw, so that the steel c can be
adjusted in this direction according to the diameter of the screw S, whilst the
steel d, which must be adjusted according to the pitch of the threads, parallel to
the axis of the screw S, is displaceable in the holder D. For this purpose in the
holder D there is provided a plug E which by means of a set screw F can be dis-
placed parallel to the screw S, and in the axis of which a pin f is arranged equally
displaceable. This pin f is provided in one end with an opening for receiving the
steel d whilst at the other end it terminates in a screw on which a nut f'is screwed,
so that the steel d may be pressed firmly against the end surface of the plug E and
so fixed.
By using two steels, the sides of the screw threads can be cut separately; whilst
one side of the screw-threads is cut during the forward movement of the carriage B
by the one cutter the other side is cut by the second cutter during the rearward
movement, the steel, which corresponds to the corresponding carriage movement,
being moved in, whilst the other steel is removed from the screw S.
By turning the sides of the screw-threads separately, not only cleaner and
better finished screw threads are obtained, but the cutters remain sharp much
lunger; also the force required for cutting the threads is considerably reduced
and equalized since the same force cuts during the forward and back movement of
the cutters. Time is also saved!
Having now particularly described and ascertained the nature of this in-
vention and in what manner the same is to be performed I declare that what I
claim is:
In screw cutting devices the arrangement of two steel holders C and D seated
ounnart with cutting steels c and d directed opposite one another,

page_text: one of these cutters d being adjusted, corresponding to the pitch of the screw-
threads to be cut, parallel to the axis of the screw and the other cutter c rectangu-
larly to the same the one side of the screw-threads being cut by the back movenient
of the carriage B carrying the steel holder. C and D and the other side by the
ferward movement of said carriage.
5
Dated this day one 109.
HERBERT HADDAN & Co.,
18, Buckingham Street, Strand, WC.; London, Agents to Applicant.