Year: 1885

page_text: I, ADOLF SIEWERDT, Engineer and Manager, of Oerlikon near Zurich, in the
Republic of Switzerland, do hereby declare the nature of my said invention and
in what manner the same is to be performed to be particularly described and
ascertained in and by the following statement :-
between the tooth wheels of the head-stock.
2) to cut threads of any pitch as accurately by the sole use of worm and rack, as
when a guide spindle is employed.
Fig. I is a front view of the lathe.
"
II a plan.
III a rear view.
"
"
IV a horizontal section of the head stock along line A B B¹ of Fig. I.
(Figs. I to IV show an arrangement of change wheels such as is intended for
ordinary turning.)
Fig. V is a vertical section along C-D through the head-stock, partly also
through the stand (showing the method of driving the countershaft e).
Fig. VI is a plan of the head-stock with change wheels for cutting screw threads.
Fig. VII is a section (along line E E', F F of Fig. II) through the cheeks or bed
of the lathe and partly through the slide-rest or carriage, with the casing for the
worm holder adapted to put the worm in and out of gear with the toothed rack,
and with the wheels for producing the longitudinal and transverse motion or cross
feed.
Fig. VIII is a horizontal section of the worm holder casing along line G H, with
partial section through the cheek.
Fig. IX is a section of the lathe bed along line J-K, with toothed rack v and
axle n and front view of the tail stock.
Figs. X and XI are respectively a section along line L-M and an end view of
the feed motion casing.
Fig. XII is a vertical section along line NO through the head-stock.
Figs. XIII and XIV are respectively cross-section and longitudinal section of;
a detail (tooth-wheel with worm).

page_text: The head stock a, shown by Figs. I to VI and XII in elevations plan and
sections, with the covers a¹ screwed on, is a perfectly closed casing, in which the
tooth-wheels are lodged vertically under each other and covered.
The head stock a has a main spindle b (Fig. XII) on which is mounted, in
a similar manner as in the case of ordinary lathes, a stepped cone c with spur
wheel c¹ and spur wheel for the transmission of power. On an axle e, rigidly
fixed in the lower part of the head-stock a, turns loosely a sleeve f, provided with
spur wheel f¹ and spur wheel f2, which sleeve is prevented from lateral shifting by
a cam g, Fig. IV, but can be placed in and out of gear with the teeth of the main
spindle wheels by turning the lever h, situated outside the head-stock. h and ha
are stops or abutments for the lever h.
To the rear end of the head stock a is cast a small box or holder containing an
adjustable sleeve i adapted to take up the axial pressure of the lathe-centre.
Outside the counter sleeve or counter-point a stepped cone k is mounted on the
main spindle, for rapidly getting the various speeds of feed motion for turning.
By means of a strap the said cone k sets in motion a stepped cone m carrying
a spur-wheel, and by means of intermediate tooth gearing, as shown by Fig. IV, the
grooved axle n.
For cutting screw threads, however, a change-wheel o, corresponding to the pitch
of the throad to be cut, is put on the main spindle, in place of the stepped cone m,
which wheel, in conjunction with change or intermediate wheels, as shown by
Fig. VI, imparts likewise motion to the grooved axle. The axle n passes through
the casing q, cast on to the carriage or slide rest ? and provided with cover q¹.
Inside this casing q is situated a worm holder Q held by the casing and adapted to
turn on the grooved axle n, which holder may be lifted and lowered by means of
lever and eccentric 8.
For the longitudinal and transverse motion of the slide rest serves a spur wheel t,
mounted on the grooved shaft (see Fig. VIII) and connected with a bevel wheel t¹;
the spur-wheel t imparts its revolution to a worm u by means of a wheel u¹, so
that, when the worm-holder Q is lifted by the lever and the eccentric 8, the
worm enters the exactly shaped (accurately cut) toothed rack v, connected with
the cheek, or bed of the lathe, whereby the carriage or slide rest p receives its
automatic longitudinal motion.
In the annexed drawing (see Figs. VII, VIII, XIII and XIV) the wheels t and u¹
are of equal size, and to obtain a compact arrangement, the thread of the worm u
is continued into the teeth of the wheel u¹. The latter arrangement is shown in
detail by Figs. XIII and XIV.
The longitudinal motion of the slide rest by hand is produced as soon as the
worm u has been removed from the toothed rack v, by means of the pinion w on
the shaft x carrying a crank or handle, which pinion is always in gear with the
toothed rack.
The automatic transverse motion is produced by a bevel wheel y, lodged in the
casing (q and q¹) of the slide rest carriage and constantly in gear with the bevel
wheel t connected with the spur wheel t mounted on the grooved shaft n.
Outside of the bearing of the wheel y the wheel axle is provided with a cone y¹
and a brake key z, for coupling the spur wheel a° with the bevel wheel y by
friction produced by pressure upon the cone y, in order to set in motion the wheel b°
fixed on the screw-spindle c°, which sets in motion the cross slide p. The brake
key is preferably a handwheel z, forming a nut on the screw threaded extremity of
the axle of the wheel y. In this manner the automatic transverse motion of the
cross slide is likewise obtained from the grooved axle n. The transverse motion of
the upper slide rest may, after loosening the brake key z, be produced by means
of a hand wheel mounted on the square extremity of the spindle c°.
As shown by the drawings, the tooth wheel or speed gear, situated between the
spindle b and the shaft e are completely incased, so as to leave only a top-opening,
sufficient for the passage of the driving band.

page_text: 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
In lathes:
1.) A head stock a having its speed gear or intermediate shaft situated under the
main spindle b, and forming (or being provided with) a casing which completely
encloses the tooth wheels of the speed gear, but leaves at the top an opening or
passage for the driving belt.
2.) The means or mechanism for producing either the motion of the slide or tool-
rest for screw cutting with worm and toothed rack, or the longitudinal or transverse
feed motion (or both) for ordinary turning or facing, the said mechanism chiefly
comprising a fixed rack v, a worm u adapted to produce the longitudinal motion of
the tool rest or carriage and to be set in and out of gear with the said rack, a shaft n
and gearing adapted to produce at will either the rotary motion of the worm u or
the ordinary cross feed of the tool rest or both motions at the same time, and
a train of change wheels adapted to transmit the motion of the spindle b upon the
shaft n when required for cutting screw threads.
3.) The means or mechanism for setting the worm u in and out of gear with the
rack and for producing the rotary motion of the worm u from the shaft n, chiefly
comprising a spur-wheel t, a spur wheel ¹ having a continuation of the screw
thread of u cut into its teeth, a worm holder Q adapted to turn on the shaft n for
a distance sufficient to set the worm in and out of gear with the rack, and
a casing q, q' forming a bearing for the worm holder Q and an abutment for the
wheel t.