Improvements in and in connection with Lathes and other like Machinery.
Year: 1897

page_text: Date of Application, 6th July, 1897-Accepted, 16th Oct., 1897
COMPLETE SPECIFICATION.
Improvements in and in connection with Lathes and other like
Machinery.
I, EPHRAIM SMITH, of 127 Oliver Street, Boston, in the State of Massachusetts,
one of the United States of America, Manufacturer, do hereby declare the nature
of this invention and in what manner the same is to be performed, to be particu-
larly described and ascertained in and by the following statement:-
This invention has for its object the production of simple and effective means
for controlling the rotative speed of the work-holder, commonly known as the
spindle, in lathes or cutting off machines and other like apparatus.
As the tool is fed transversely to the longitudinal axis of the work, in lathe
work, such as facing off anu squaring up, it is necessary to run it slow enough to
prevent the point of the tool from being worn off, but it is also very desirable that
this uniform cutting speed should be maintained as nearly as possible, as the tool
works towards the centre.
By my invention I am able to maintain a uniform cutting speed at the point
of the tool, as the diameter of the work decreases, whereby the operator is enabled
to do from three to four times the amount of work, in a given time, that he could
with a machine unprovided with my improved speed controlling means.
I find it very desirable that the machine should be under complete control of
the operator, both as to the number of revolutions the spindle of the lathe or other
apparatus should make, and also as to the amount the speed should increase from
the periphery to the centre of the work, according to the hardness, size, and nature
of the work being done.
I have devised simple means, controlled by the feed of the tool, to gradually
increase the speed of rotation of the work, and I have made provision for auto-
matically stopping the feed at the desired time.
Heretofore, in cutting apparatus of this class, it has been customary to use a
comparatively thick cutting tool having a wide face, in order to give stiffness to
the tool and prevent its running crooked, it resulting in a certain waste of the
work, and at the same time requiring more power.
I have shown a movable guide or support which embraces the tool near the
point, and prevents lateral movement thereof, so that a very thin, narrow faced
tool may be employed, with a consequent reduction in the amount of waste and
power required.
Until the tool enters the work the guide embraces and supports it, but as the
tool enters the work deeper the guide is engaged by the work and moved away
from the tool, so as not to interfere with its further operation.
Fig. 1 is a side elevation partly broken out of a cutting lathe, shown as driven
by an electric motor, with one form of my invention applied thereto.
Fig. 1 is a detail to be referred to.
Fig. 2 is a right hand elevation of the apparatus shown in Fig. 1.
Fig. 3 is a partial top or plan view thereof, partially broken out to show more

page_text: Fig. is a diagrammatic view of the motor and its variable resistance device
or rheostat, and
Fig. 5 is an inner edge view of the tool holder to be described.
I have chosen to illustrate my invention as applied to a machine for cutting
metal bars, shafting and the like, “though it will be obvious hereinafter that my
invention is equally well adapted for use in connection with other forms of
apparatus wherein the work is held in a rotatable holder and the tool fed trans-
versely thereto.
The bed plate A having uprights or standards A', A² to support the hollow
barrel B of the face plate B having dogs or chucks 13 thereon to secure the work
in place; the carriage C having transversely movable thereon the tool holder C
and C actuated by a feed screw C* are and may be of usual or well known con-
struction in machines of this class.
The front end of the feed screw C* is mounted in a bearing C³ on the carriage
and is provided with the usual worm wheel c and hand wheel c¹, a shraft a extended
along the side of the bed plate A and rotatable in bearings a¹, a², thereon having
fast upon it a worm a to actuate the worm wheel c when in engagement therewith.
As shown in Fig. 2, the bearing a is mounted on an arm a pivoted to the bed
and is held in operative position by a latch as, release of the arm permitting
the bearing a to drop sufficiently to disengage the worm wheel and worm referred
to, thereby stopping the feed of the tool holders.
at
'
:
I have shown in Fig. 1 an electric motor M secured in any suitable manner
adjacent the apparatus, and having secured to its rotatable member'm a pinion m³,
sec dotted lines Fig. 1, and full lines Fig. 1^, said pinion meshing with a gear m²
which in turn engages a gear m³ fast on a shaft m mounted in a bearing A3 on the
standard A¹.
This shaft m¹ has on its outer end a pinion m³ in mesh with a large gear
.me
fast on a barrel B of the work holder (see Fig. 1) to thereby, rotate the same
through the train of gears, and a band 10 is shown in Fig. 1 connecting
pulleys mo, a on shafts m and a* respectively, to rotate the latter.
While the connections, herein described between the motor M and work holder
are the most convenient for adaptation in the present case, it is to be understood
that the intermediate connections may be varied in any desired manner, as they
are not of the gist of the invention.
A rheostat or variable resistance device R of well known form is shown as mounted
for convenience on the bed plate A between the standards A1 and A2, and in circuit
with the generator G and motor M, as shown in diagram Fig. 4, whereby the
current to the motor may be regulated, and thereby its speed.
The movable member or controller r of the rheostat is shown in Fig. 3 as pro-
vided on its axis with a pinion in engagement with a rack, pivotally
connected by a link d to a block adjustable longitudinally on an arm
means of a suitable set screw 15.
by
A rock shaft * is mounted in suitable bearings 20 on the bed or frame A and
has fast thereon at one end a disc ³, to which by a clamp on the arm; the
latter is secured in desired adjusted position, the said arm being mounted on the
rock shaft.
1
+
By rotation of the latter in one or the other direction the arm will be
rocked to actuate the movable member' of the rheostat, to vary the resistance of
the motor circuit, and consequently the speed of the latter and the apparatus
driven thereby.
A second am is secured to the rock shaft near the carriage C, and a link d
having at one end a block ds to be adjusted by a set screw 8 on the arm do, is
pivotally connected at its other end to one of the tool holders, as C, clearly shown
in Figs. 2 and 3.
.
r.
..
r
7.37
The tools T and T' are held in the holders in usual manner, and it will be
understood that the work, such as a bar, shaft, etcetera, is firmly secured in the

page_text: work holder and the latter rotated, the tools approaching the longitudinal centre
of the work as they enter the latter.
This transverse feed of the tools is controlled by the rotation of the feed
screw C*, the latter being actuated automatically through the worm wheel c and
worm a³, or by means of the hand wheel c¹.
: 1
When the tool begins to engage the work the speed of rotation of the latter
must be very slow, in order to avoid breakage or severing of the tool, and the
resistance in the motor circuit will be greatest, but as the tool enters and nears
the centre of the work' the speed of rotation should increase in order that the
surface speed of the work at the cutting point should be as near uniform as
possible.
Accordingly, the resistance is gradually decreased as the depth of cut increases,
and such variation in the resistance is governed by the transverse feed of the tool.
Referring to Figs. 2 and 3, it will be obvious that movement of the tool
holder C in the direction of arrów 3 will rock the shaft * to, through the inter-
mediate connections, move the rack 3 to rotate the movable member r of the
rheostat in direction of arrow 4, Fig. 3, to thereby gradually decrease the resis-
tance, and correspondingly speed up to the work.
In the drawings, the parts are shown in position after the apparatus has been
started, but with the work omitted to avoid confusion.
and
It will be obvious that by varying the position of the blocks d, and 'd,
also by setting the arm on the rock shaft d* the initial speed and the range
of speed from starting to stopping of the apparatus, may be regulated to conform
to the size and character of the work.
. .
'By this adjustment, the machine may be started at any desired speed, and the
speed increased from such point.
In Fig. 2 a pin 30 is shown on the holder C, to engage and automatically trip
the latch when the cutting edge of the tool has reached a certain depth, and as
soon as the latch is tripped the worm shaft a moves to throw the feed
mechanism out of operation, and the speed of the work holder then remains
constant unless the current is at the same time out off from the motor.
I have provided a novel and effective device for guiding the leading tool, as T,
until it enters and makes a seat for itself in the work, so that the tool may be made
very thin without danger of running crooked:
On the holder C I have herein shown a strong movable arm f, pivoted at f¹
on the holder and having an offset car fat its outer end, grooved in fts under
face to embrace the back of the tool T, as clearly shown in Figs. 2 and 3 near the
point of the latter, the lower edge 0, Fig. 5, of the tool being bevelled to enter
a V-shaped slot C10 in the part C5 of the tool holder.
A roller or other stud f* is mounted on the ear in position to be engaged by
the periphery of the work, and as the tool enters deeper and deeper into the latter
the arm is raised gradually from the tool by such engagement with the periphery
of the work.
By the time the tool has made a groove or seat for itself as it were, there is no
further danger of breaking, or deviation from its course and the guide has to
perform no further function.
It will be obvious from the foregoing that my invention may be applied to any
form of apparatus wherein the work is held in a rotatable holder and presented
to a tool having a feed movem ent transverse thereto, wherein it is desired to
preserve a uniform rate of speed of the work at the point whereat the tool acts,
and accordingly my invention is not restricted to the apparatus herein shown,
nor to the precise form of connections between the feed of the tool and the variable
resistance.
If it be desired to operate the feed of the tool by hand, it will be obvious that
5 the speed may be controlled as hereinbefore described, and by loosening the
clamp the rheostat controlling mechanism is disconnected from the feed."

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 or other machinery requiring similar regulation and control of
speed:
1. The use in an apparatus of the class described, of a rotatable work holder, a
cutting tool adapted to be fed transversely of the work, an electric motor to
rotate the work holder, a variable resistance in circuit with said motor, and means
governed by feed of the tool, to vary the resistance and thereby the speed of the
motor, substantially as described.
2. The use in an apparatus of the class described of a rotatable work holder,
an electric motor to rotate it, a variable resistance in circuit therewith, a tool
holder, means to feed it transversely to said work holder, connections between
the resistance and said means to vary the latter proportionally to the position of
the tool holder, and means to vary the speed of the apparatus between predeter-
mined points, substantially as described.
3. The use in an apparatus of the class described, of a rotatable work holder a
tool holder movable transversely thereto, a tool rigidly mounted in the holder,
and a movable guide adapted to embrace the back of and steady the tool as it
enters the work, the work engaging and moving the guide away from the tool, as
the latter enters the work, substantially as described.
4. A tool holder, having a tool held rigidly therein, and a guide movably
mounted on and carried by the holder, to embrace and steady the tool near its
point as it enters the work, engagement of the surface of the latter with the guide
moving it out of engagement with the tool, substantially as described.
5. A tool holder having a grooved seat, a tool rigidly held in the holder and
having a bevelled lower edge to rest in the seat, and a guide movably mounted
on the holder to engage and steady the tool near its point, substantially as
described.
6. The use in an apparatus of the class described, of a work holder, an electric
motor to rotate it, a rheostat in circuit with the motor, a tool holder, means to
feed it transversely to the longitudinal axis of the work holder, connections between
said feeding means and the rheostat, to control the latter and thereby the speed
of the work holder, and means to stop the feed and movement of the rheostat at
a predetermined point, substantially as described.
Pateu
the on day of July 1834.
WM. BROOKES & SON,
55 and 56 Chancery Lane, London, Agents for the Applicant.