Improvements in Mechanism for Operating Lathes and other Machines.
Year: 1890

page_text: Date of Application, 25th Jan., 1890-Accepted, 22nd Mar., 1890
COMPLETE SPECIFICATION.
Improvements in Mechanism for Operating Lathes and other
Machines.
A communication from JULIUS WILHELM VON PITTLER, of Gohlis-Leipzig, in the
Empire of Germany, manufacturer.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex,
M.I.M.E., 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 :-
:-
In operating lathes and similar machinery, to accomplish the purpose of which it
is necessary that the speed and direction of motion should be variable at will a specia!
clutch must be used.
Hitherto, in turning-lathes for example, the speed of rotation has been made
variable by the employment of step pulleys, while the direction of motion was varied
by using two straps, the one passed over the pulley in the ordinary way, and the
other crossed.
Now, through the use of the mechanism forming the object of this invention,
variability of speed is ensured without the employment of step-pulleys, and the
direction of rotation may be changed without using two straps.
This mechanism is illustrated in the accompanying drawings, figs. 1 to 7, in two
modifications.
Fig. 1 is a front view of the first type of mechanism. Fig. 2 is a horizontal
section thereof through line A B. Fig. 3 is a side view, and Fig. 4 a partial
cross section through line C D. Fig. 5 shows the arrangement as applied to
shaft b. Fig. 6 is a front view of the second modification. Fig. 7 is a horizontal
section.
The arrangement is as follows:-In a cross-frame provided with four bearings a
two shafts are mounted at right angles to each other. Shaft carries a large
surface friction pulley or disc c and receives motion through pulley d from the
main driving gear. Shait 6' carries two friction pulleys e e adjustably arranged
upon the said shaft, and causing the same to revolve with them by means of the
feather i. The nave-shaped bearings a a¹ of shaft 61 are capable of a sliding motion
in the frame, and thereby enable such shaft b¹ to be shifted transversely so as to
bring friction pulleys e e¹ in, or out of, contact with the friction surface of dise c.
By making friction pulleys e el adjustable upon their shaft these pulleys are
rendered capable of being set at any desired diameter of a position upon the surface
of disc c, whereby either of the pulleys may be caused to revolve at the desired rate
of speed. Through the transverse displacement of shaft it is possible to bring
either one or the other of the friction pulleys e el into contact with the friction
disc c at a given moment, as the case may be, so that the direction of rotation of
shaft 6' may be instantaneously changed, or its motion stopped altogether.
But not only is it possible to alter either the rate of speed or the direction of
motion in a moment, by correspondingly adjusting the friction rollers and the
shaft 6, but, by properly setting the pulleys ee against the friction surface of
disc C, it is possible to vary the rate of speed and direction of motion simultaneously.
Thus in fig. 1, for example, friction pulley e is set nearest to, and friction pulley e¹
farthest from the centre of disc c. Assuming, now, that disc c turns in the direction
of the arrow shaft b, or, in other words, driving-pulley will, when pulley e is
brought against the friction surface of the disc, turn slowly in one direction
whereas if pulley e¹ is placed against the surface of the said disc, the said driving
pulley will turn rapidly in the opposite direction.
The transverse adjustment of shaft is effected by means of screw holts m m²
operated by a chain or cord n passed over pitch wheels or pulleys o which are

page_text: connected with the said screw-bolts; for, according as one end n¹ or the other n² of
the said cord or chain, is drawn along, the corresponding screw bolt say m, revolves
in such a manner that it actuates the bearing a, which is situated behind it, in the
direction of friction disc c; the consequence being, that pulley e is brought into
frictional contact with disc c; while at the same time the other screw bolt m¹ retains
or allows a spring to move the bearing which is behind it, in such a position as to
keep pulley e¹ out of contact with disc c.
In thus transversely displacing shaft b' for the purpose of changing the direction
of motion, both pulleys e and e¹ are at a certain moment brought out of frictional
contact with disc c. If, at that moment, the adjustment of the said shaft be
discontinued, the operation of the whole friction gear suddenly stops. It is of
course impossible in this arrangement for the apparatus to be thrown into, or out
of, gear, automatically.
The chain or cord ends n' n² in a lathe (which is here taken as an instance) or
any machine of a similar description are connected with and moved by, a lever p.
The transverse adjustment of shaft may be effected by means of suitably
arranged eccentric levers, also operate by means of a cord, instead of by screw
bolts.
Also friction between pulleys e e¹ and disc c can be obtained by displacing
transversely shaft 6 instead of shaft & or by turning the same to a given point. An
instance of this is illustrated in figure 5. The posterior hearing a is here connected
with a screw boltz which similarly to screw bolts m m' is operated by means of a
cord and thereby causes a displacement of bearing a. Inasmuch, however, as the
other bearing a is not similarly sbifted, shaft 6 turns within this bearing, whence
results an
oblique position of disc c as indicated by the dotted lines and thus
the said disc is brought into frictional contact with either one or the other of the
pulleys e e¹.
The adjustment of friction pulleys e e¹ on shaft 6' takes place in the following
manner :-
Along shaft a spindle t is movably fitted in the frame. One half of this spindle
is provided with a screw thread while on the other half thereof loosely revolves a
tube u also threaded, throughout its length. This spindle t receives a rotary motion
from a stiff cord v passed over two small pulleys one of which is mounted upon
the said spindle and the other suitably secured to the lathe or machine. And in
the same way a cord w passed over two small pulleys of which one w¹ is mounted
upon tube and the other fixed to the lathe, imparts motion to the said tube u.
Both in the screw thread of spindle and in that of tube u engages a yoke or
fork shaped clutch lever and either of these levers or yokes is in gear with
one of the pulleys e and e¹. Now according as either the spindle t or the tube u is
set in motion by cord vor w respectively yokes a will advance or recede on the
screw threads of the spindle or tube, as the case may be, and correspondingly
operate pulleys e and e respectively. This enables the speed of rotation of either
of these pulleys e and e¹ to be adjusted to a nicety; while, here too, no automatic
or spontaneous displacement of the said pulleys can take place.
The modification shown in figs. 6 and 7 differs from the arrangement above
described in this particular, that one friction pulley e only is here employed, and
that the same, instead of revolving with shaft turns on the latter, the said shaft
being in this instance stationary and provided with square journals. Nor is, in this
case, the friction pulley thrown into gear with disc c by shifting the shaft but
the arrangement is reversed viz. the said disc is brought in contact with pulley e
by the longitudinal displacement of its own shaft b effected by the pressure of a
screw y which receives a rotary motion from cord y.' driving a roll y².
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me
by my foreign correspondent I declare that what claim is '-
1. A friction gearing whereby friction pulleys, such as e e¹ are brought into

page_text: frictional contact or gear with a large disc such as c for the purpose of changing
the direction of motion and varying the speed, arranged in such a manner that two
shafts, such as or one shaft such as 6' are capable of transverse or lateral
displacement; while the pulleys e e¹ may be set independently of each other at any
given diameter or distance from the centre against the surface of disc a
proper operation of an endless cord substantially as described and illustrated in the
accompanying drawings.
by the
2. For the purpose of adjusting a shaft such as in the manner indicated in
the preceding claim the arrangement of two screws such as m m¹ in the bearings
of the shaft, carrying chain or cog wheels such as o operated by a chain or rack
which are capable of being moved backwards and forwards by means of an endless
cord drawn in the desired direction and correspondingly cause the screws m m¹ to
turn to the right or to the left substantially as described and illustrated in the
accompanying drawings.
3. For the purpose of enabling either of two friction pulleys such as e e' to be
adjusted independently of the other so as to touch a friction disc such as c at a given
distance from each other, the arrangement of a spindle such as t one half of which
is provided with a screw thread and which receives motion from an endless cord;
in combination with a tube such as u also threaded externally and passed on the
other half of the said spindle (which is not threaded) in such a manner as to be
capable under the action of another endless cord of revolving independently of the
said spindle; and with guide forks or yokes such as a one of which is engaged
with the screw thread of the spindle and the other with that of the tube each being
at the same time in gear with a friction roller such as e and e¹ respectively, all
substantially as described and shown in the accompanying drawings.
Dated this 25th day of January 1890
W. P. THOMPSON & BOULT,
Agents for the Applicant.