Year: 1899

page_text: 1, ALBERT ROLLER, of Waiblingen, in the Kingdom of Wurtemberg, Germany,
Tool-Maker, do hereby declare the nature of this invention to be as follows:-
The object of this application consists of an improved screw thread cutting
stock and die which by reason of its specially devised clamping arrangement
adapted to the thread cutting die, enables the same to be quickly, promptly,
and securely removed and replaced.
The device consists essentially of a central annular part or holder provided
with handles at each side, projecting to the requisite extent equally, or in another
modification having a ring handle at one side and a straight handle at the other.
The metal part comprises the clamping device and holder for the die and
A screw which can
possesses a certain springiness by reason of slots cut in it.
be turned by means of a suitable key is provided in order to draw the divided
parts of the said clamp nearer together or to push them further apart. Conse-
quently these parts exercise when the screw is turned in the proper direction
a strong pressure upon the die inserted between them, and thus prevent the
same from becoming displaced.
In order to protect the said die when in place against any movement or turn-
ing, it is arranged to engage by means of a notch with a projection forming
part of the holder.
In order that the die may have permanently the requisite position within the
clamp the latter possesses on one side a projecting ridge which serves to pre-
vent the die from falling down when it is inserted in the clamp.
The release and replacement of the die is effected by simply unscrewing the
clamp by means of the aforesaid screw.
Modifications in the construction may be introduced according as very large
or very small dies are to be made use of.
C TL 1800
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C.,
Patent Agents for the Applicant.

page_text: '
the same is to be performed to be particularly described and ascertained in and
by the following statement:-
:-
The object of the present invention is an improved device for cutting screw
threads which is characterised by the specially constructed clamping arrange-
ment for the thread cutting dies.
The device is illustrated in the accompanying drawings in Figs. 1 to 13 in
which
Figures 1 to 5 shew the clamping device in combination with an ordinary
simple cutting die:
Figs. 6 to 13 shew the clamping device with an adjustable die, and the
mechanism effecting the adjustment thereof.
which in
The stock consists of a central annular part a with handles
Figures 1 to 3 are both straight, while in the form of construction shewn in
Figure 5 one of these handles is in the shape of a ring d.
The central part comprises the clamping device and serves as holder for the
removable cutting die e and possesses a certain springiness owing to slots cut
therein. A screw which can be turned by means of a suitable key is provided
for drawing together the two parts of the clamp a or for pushing them farther
apart. Consequently when the screw is turned in the proper direction these
parts exercise a strong pressure upon the die e inserted between them and
prevent it from becoming displaced.
In order to prevent the die e from moving or turning when in the stock it
engages by means of a notch h (Fig. 4) with a projection i forming part of the
stock a.
In order that the die may always have the proper position in the stock, this
latter has on one side a projecting ridge (see Figs. 2 and 3) which serves
to prevent the die e from dropping out when it is inserted in the stock.
The die e can be inserted or changed on tightening or loosening the clamp
device by means of the screw g.
The arrangement illustrated in Figure 5 is specially adapted for smaller
stocks.
This adjustment device with the die, can. be provided with an arrangement
for altering within given limits the diameter of the die and consequently to be
able to easily adapt the cutter to the size of the article which is to be screw
threaded.
For this purpose the die e is slit on one side and has on the outer periphery
at the slit place two concentric semicircular borings which form an annular
conical projection having a diameter which corresponds to the slit m of the
die e so that the annular projection is equally divided by the slit.
l
Two screws no act on this double conical annulus, which screws engage in
the clamping device and act instead of the notch i to prevent the die from
turning.
One of these screws n when screwed up acts as a wedge between the halves
of the annular projection in the slit m and drives the die e apart as this latter
possesses a certain amount of elasticity owing to its star-shaped aperture; while
the other screw o when turned, engages with the annulus and compresses the
die. In this manner the width of the slit m can be varied to a certain extent
(about 1m.m. in 3/8 inch threading). In order to obtain this result the inner
screw n is coned while the outer screw o like the annulus 1, terminates in an
annular cone.
The two screws no are passed through one another, the inner one being
preferably turned by means of a socket key, and the outer one by means of an
ordinary spanner, as for instance, that shewn in Figure 13 in which one end y
is intended for the screw n and the other end q for the screw o.
It is advisable when cutting so-called English threading to use an expansion
chuck (shewn in Figure 10 in side elevation and horizontal section) which

page_text: consists of an annular sleeve and has a cut out piece for the insertion of the
screws n o.
In cutting gas pipe threading the chuck illustrated in Figures 11 and 12 may
be used with advantage, said chuck consisting of a cylindrical sleeves and having
an expanding device composed of slots and screws for an inserted sleeve
which serves as guide for the work. This chuck has of course a similar cut-
out piece r.
In using a thread cutting device of this kind, by screwing in the screw n
the annular die is expanded, and by screwing up and screwing in the die e
is contracted and reduced in diameter, which is very desirable for cutting
threads well and uniformly and in the dies hitherto used in so called American
stocks no adjustment in the diameter was possible.
The stock for expanding the slit die can be provided with angular apertures pl
so that it can be used conveniently as a wrench for taps, etc.
The slit die described above can also of course be used for machine work.
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:―
Improved die stock characterized by the arrangement that the removable die
is firmly held by an annular slit stock the two halves of the latter being adapted
to be expanded or contracted by means of a screw or the like, substantially as
described.
D
IL
"
W. P. THOMPSON & Co.,
Of London, Liverpool, Manchester, and Birmingham.