IMPROVEMENTS IN SCREW CUTTING LATHES
Year: 1884

page_text: I ALFRED DOLIZY Engineer, of 61 Rue d'Angouleme in the City of Paris and
French Republic do hereby declare the nature of my Invention for IMPROVEMENTS
IN SCREW CUTTING LATHES and in what manner the same is to be performed, to
be particularly described and ascertained in and by the following statement:-
My invention relates to improvements in automatic screw cutting engines and
specially to a novel construction of the slide rest and the parts for operating the
same,
My improved slide rest is composed of the following parts.
The slide rest proper which moves on the bed of the lathe or engine is of
ordinary construction and carries a second slide rest which is surmounted by two
transverse slides.
The back and forward movement of the first transverse slide rest is effected by
means of a screw provided with a suitable ring for regulating the movement of the
said screw and a lever with counterweight and pawl which latter gears into a
ratchet wheel fixed to the screw for effecting the operation of the upper slide rest
or tool slide.
The chief slide rest is provided with a bearing (denominated stop fork) and a
transverse spindle which carries at the one end a bevel wheel and at the other end
a pinion which gears into a wheel fixed on the screw of the first transversal slide
rest. A spindle arranged horizontally to the lathe bed, rotates continuously in
the same direction and is provided with two bevel wheels fixed at requisite
distance apart.
A coupling rod runs parallel to the bed of the lathe carries at one end a lever for
operating the coupling and is carried at the other end in a suitable bearing.
Two stop rings are arranged on this rod and can be adjusted at will according to
the length of travel required.
The accompanying drawings represent an automatic screw cutting engine
constructed according to my invention.
Figure 1 is an end view.
Figure 2 a front view of my improved engine. A is the frame of the engine, B
is the headstock with the driving gear and C the sliding puppet, D is the shafting

page_text: with double drums for alternate action-E is the strap drum on the longitudinal
spindle c. F is the bearing for the longitudinal spindle e. G are the bearings, m
the slide rest a for the transverse spindle c.
The automatic action is attained in the following manner.
When the engine is put in action the slide rest a is advanced the bevel wheel
sector b on the cross spindle c gears with the bevel wheel d on the longitudinal
spindle e and receives in this manner its rotary movement.
The bevel wheel d is fixed on the spindle e between the rings y y¹ and is held
against the surface of the ring y¹ by means of the spiral spring so that the wheel d
can give way when the gear with the sector b is too strong.
By this means the rotation of the pinion f is transmitted to the wheel g fixed
to the screw h of the cross slide j.
This screw h carries a lever K with counterweight and a pawl L.
The lever K oscillates from the left the right whereby the pawl operates on the
ratchet wheel m and moves the same by one or two teeth and this said ratchet
wheel being fixed on the screw x causes the slide rest or tool holder o to advance
according to the requirements of the screw.
As soon as the lever has passed the centre of gravity the saine falls back until
the screw p on the slide rest j comes in contact with the slide n where it is arrested
during the movement of the lever and the screw h.
The cross slides jo now move back into their respective positions so that the
tool is out of contact with the screw.
During the return movement of the cross slides jo the forked bearings attached
to the main slide rest a, strikes against the ring t on the coupling rod n and
communicates its motion to the same which said rod operates on the gear v and
changes or reverses the movement.
When the main slide in its return motion has reached the requisite position the
same operations as above described are repeated in contrary direction and with the
Eame parts used in the first instance but as the lever fixed to the screw h of
the cross slide j now oscillates from right to left the pawll does not operate the
ratchet wheel m.
The two cross slides jo advance simultaneously until the screw 9 on the slide j
comes in contact with the slide n and is stopped. The slide; always returns to its
original position but the slide o can be caused to advance further according to the
requirements of the screw and the depth of the threads to be cut. It is evident
that the form and dimensions of the parts can be modified in various ways without
departing from the tenor of my invention.
Having now particularly described and ascertained the nature of my invention
and the manner of performing the same I declare that what I claim is
1-The system of constructing my automatic slide rest for screw cutting engines,
the devices for operating the same and for coupling and uncoupling the parts and
also the application of my gearing for imparting the desired movement or any mere
modification of the same substantially as described and shown in the accompanying
drawings.
2-The application of my system of slide rest for automatic screw cutting to all
kinds of existing lathes substantially as described and shown in the accompanying
drawings.
3-The combination of the main slide rest a and the cross slide j and o with the
bevel wheel sector b, the cross spindle c bevil wheel d and spindle e substantially as
described and shown in the accompanying drawing.
4-The combination of the slide rests a, j, o, sector b, wheel d and spindles c
and e with the rings or collars y y¹ the adjustable rings or collars t and the rods or
spindles uv for coupling and uncoupling the parts substantially as described and
shown in the accompanying drawings.

page_text: 5. The combination of the slide rests aj o with the pinion f, wheel g, screw h
lever k, pawl and ratchet wheel m substantially as described and shown in the
accompanying drawings.
6-The general combination and arrangement of the parts of my improved
automatic slide rest and the parts in connection with the same substantially as
described and shown in the accompanying drawings.
ALFRED DOLIZY,
Applicant.