Improvements in Screw Cutting Lathes.
Year: 1893

page_text: Date of Application, 3rd Oct., 1893-Accepted, 11th Nov., 1893
COMPLETE SPECIFICATION.
Improvements in Screw Cutting Lathes.
I JAMES HERBERT PATERSON, of Ingersoll in the Province of Ontario and
Dominion of Canada, Machinist 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 :-
The object of the invention is to provide a new and improved screw cutting lathe
which is simple and durable in construction, very effective in operation and arranged
to permit the operator to easily and quickly bring the cutting tool back to the
exact position on the beginning of the cut, so that a perfect and uniform thread is
quickly produced and no time whatever is lost by the operator being compelled to
find the beginning of the cut, as is necessarily the case with screw cutting lathes as
now constructed.
The invention consists principally of a mechanism intermediate of the spindle
and the feed shaft, and comprising an auxiliary shaft driven from the moving
carriage, and geared with the feed shaft in such a manner as to cause the latter to
rotate at a higher or lower rate of speed than that otherwise given to the feed shaft
from the spindle.
The invention also consists of certain parts and details, and combinations of the
same, as will be hereinafter described and then pointed out in the claims.
Reference is to be had to the accompanying drawings forming a part of this
Specification, in which similar letters of reference indicate corresponding parts in
all the figures.
Figure 1 is a front elevation of the improvement ;
Figure 2 is a rear sectional elevation of the same on the line 2-2 of Figure 3;
Figure 3 is an end elevation of the same;
Figure 4 is a similar view of the same with parts removed and parts broken
out;
Figure 5 is an inverted plan view of the improvement ;
Figure 6 is an end elevation of the carriage with the shafts in section;
Figure 7 is a sectional plan view of the same on the line 7-7 of Figure 2;
Figure 8 is a cross section of the same on the line 8-8 of Figure 5;
Figure 9 is an end view of the head stock and adjacent parts; and
Figures 10, 11, 12 and 13, are diagrammatic views illustrating the position and
movement of the several shafts connected with the carriage.
The improved screw cutting lathe is provided with the usual bed A, supporting
on one end the head stock B, in which is mounted in the usual manner, the
spindle B' engaging at one end the work C, held at its other end in the mandrel B'
of the tail stock B³ of the usual construction. The cutting tool C' for operating
on the work C is mounted in the usual tool holder C2 held transversely-adjustable
on the carriage D mounted to slide longitudinally in suitable bearings on the bed A.
Through the front of the carriage D passes the longitudinally-extending feed
shaft E, journaled in suitable bearings arranged on the ends of the bed A, as
plainly illustrated in the drawings.
The feed shaft E is adapted to be engaged by a half nut E'; (see Figures 7
and 8) mounted to slide vertically in suitable bearings D¹ formed on the inside of
the carriage D, the said half nut being moved up into engagement with the feed
shaft E, or down, out of engagement with the same by a pin E' projecting from
the nut and engaging eccentrically a hub Es mounted to turn in suitable bearings
n the right hand end of the carriage D as plainly shown in Figure 6.
On the outer end of this hub E3, is secured a handle or lever E' under the control
of the operator so that the latter is enabled by moving the handle downward to
CD

page_text: impart an upward sliding motion to the half nut E¹, to engage the latter with the
feed screw E. When the handle is moved into a horizontal position, then the pin E³
is in a lowermost position, as shown in Figure 6, and consequently the half nut E'
is in a like lowermost position and out of engagement with the feed shaft. Thus,
when the latter is rotating in the direction of the arrow a' shown in Figures 10, 11
and 12, and the half nut E' is in engagement with. the said feed shaft then the
carriage D moves from the right to the left, but when the said half nut is out of
engagement with the feed shaft, the carriage D is not moved by the feed shaft in
the direction mentioned.
In order to move the carriage D by hand at the time the half nut E' is out of
engagement with the feed shaft E, the following device is provided:
In the carriage D is arranged a transversely-extending shaft F carrying at one
outer end a handle F1 under the control of the operator for turning the said shaft
whenever desired. On the inner end of the shaft F is secured a pinion F' in mesh
with a gear wheel F3 secured on a short shaft F, mounted to turn in suitable
bearings in the carriage D. On the inner end of the shaft F is secured a gear
wheel F, in mesh with a rack F secured on the bed A in the rear of the feed
shaft E, as plainly shown in Figure 5, and part of Figure 2. Thus, when the half
nut E' is out of mesh with the feed shaft E, the operator, on turning the handle Fl
can impart a forward or backward sliding motion to the carriage D, as the gear
wheel Frolls off on the fixed rack F'.
But when the half nut E¹ is in mesh with the feed shaft E, and the latter is
rotated from the spindle B' as hereinafter more fully described, then the motion
given to the carriage D, causes the gear wheel F' to turn by rolling off on the
fixed rack F. The shaft F carrying this gear wheel is adapted to be
connected with a longitudinally extending auxiliary shaft G. journaled in suitable
bearings on the side of the bed A below the feed shaft E. This shaft G, forms a
principal part of the intermediate mechanism for controlling the speed of the feed
shaft E to permit of cutting any desired number of threads to the iuch on the work,
the number not necessarily being a multiple of the number of threads per inch of
the feed shaft E. To drive the shaft G from the shaft F, I provide the said
shaft G, with a beveled gear wheel G¹ mounted to turn with and to slide on the
said shaft G, and adapted to be thrown in or out of mesh with a bevel gear wheel G'
mounted to rotate loosely on a stud D' forming part of the carriage D; see
Figure 7. On the hub of the bevel gear wheel G is formed a pinion G in mesh
with the aforesaid gear wheel F', so that when the gear wheels G₁ and G' are in
mesh with each other, and the shaft F' is rotated, then the said gear wheel F
rotates the pinion G³ and the beveled gear wheel G' of the latter imparts a rotary
motion to the beveled gear wheel G' held on the shaft G whereby the latter is
rotated as soon as the carriage D commences to travel forward. When the beveled
gear wheel G' is out of mesh with the gear wheel G' then the movement of the
carriage D does not affect the said shaft G.
The bevel gear wheel G' can be moved in or out of mesh with the bevel gear
wheel G³, and for this purpose I provide the hub of the bevel gear wheel G¹ with
an annular recess engaged by a slide G' mounted to slide longitudinally in
bearings D forming a part of the carriage D. In the slide G is formed a recess
engaged by an eccentric cam G held on a transversely-extending short shaft G
mounted to turn in suitable bearings in the carriage D and carrying at its outer
front end a handle G' under the control of the operator, (see Figures 6, 7 and 8).
When the handle G' is in a lowermost position, as shown in Figures 1, 6 and 8,
then the bevel gear wheel G¹ is in mesh with the bevel gear wheel G³ and when
the operator throws the said handle G' into a vertical position indicated in Figure 13,
then the eccentric cam G' shifts the slide G' to the right, whereby the bevel gear
wheel G¹ is moved out of mesh with the bevel gear wheel G' and consequently the
shaft G is not affected by the movement of the carriage D, as previously mentioned,
but on the contrary imparts a travelling motion to the carriage D as hereinafter
more fully described.

page_text: In order to impart a rotary motion to the feed shaft E in the direction of the
arrow a', from the spindle B', the following device is provided:
On the front end of the feed shaft E is secured a gear wheel H in mesh with a
gear wheel H secured on a short longitudinally-extending shaft H' mounted to
turn in suitable bearings arranged in an arm H³ fulcrumed loosely on a longi-
tudinal shaft I journaled in the bed A, as plainly shown in Figure 2. The arm H³
is held adjustable by a bolt H in a segmental slot A¹ of a casing A² secured on
the front end of the bed A. By loosening the bolt H and swinging the arm H³
to the left, as illustrated in Figure 9, the gear wheel H' may be moved out of
mesh with the gear wheel H to prevent the revolving of the feed shaft for
the purpose hereinafter more fully described. Ordinarily, however, the gear
wheels H and H' are in mesh, and on the inner end of the shaft H, carrying the
said gear wheel H1 is secured a gear wheel H' in mesh with the gear wheel H
mounted to rotate loosely on the before mentioned shaft I and carrying on its inner
face a small pinion H7 in mesh with a gear wheel J mounted to rotate on a stud J1
secured to the face of a gear wheel J (see Figures 2 and 4) mounted to rotate
loosely on the hub K¹ of a gear wheel K held loosely on the shaft I. On the
face of the gear wheel J is formed a pinion J³ in mesh with the gear whec! I' on
shaft I.
The large gear wheel J is in mesh with a gear wheel L in mesh with an inter-
mediate gear wheel L meshing into a gear wheel L' secured on the outer end of
the spindle B. Thus, when the latter is rotated a rotary motion is given to the
gear wheel L, which, by the gear wheels L' and L imparts a rotary motion to the
large gear wheel J' and the latter, by pinion J' held on the stud J' of the said
large gear wheel J2 and rolling off on the gear wheel I' imparts a rotary motion to
the pinion J and gear wheel J and to the pinion H', so that its gear wheel H
rotates the gear wheel H' and consequently the shaft H imparts a rotary motion
to the gear wheel H on the feed shaft E. The gear wheels L and L' are journaled
in a segmental arm L³ fulcrumed loosely on the hub of the gear wheel J2; (see
Figure 2) the said segmental arm being adapted to be locked in place by a bolt L
passing through a segmental slot L' in the said arm L³.
When it is desired to cut left hand threads on the work C, the arm L³ is shifted
by first loosening the bolt L' and then moving the arm to the left to move the
gear wheel L entirely out of mesh with the gear wheel L' and the gear wheel L
also in mesh with the gear wheel L'. When the spindle B is rotated a rotary
motion in the inverse direction of the arrow a¹ is given to the feed shaft E to cut
left hand threads on the work C. Ordinarily, however, the gear wheels L³, L',
L and J are in mesh as above described and shown in the drawings.
In order to impart a rotary motion to the shaft I from the gear wheel J2 driven
from the spindle B', I provide the face of the said gear wheel J with a stud J' on
which is mounted to rotate a gear wheel J in mesh with a gear wheel I' secured
on the said shaft I, see Figure 2. On the hub of the gear wheel J' is formed a
pinion J in mesh with the gear wheel K previously mentioned and adapted to be
held temporarily stationary by a mechanism hereinafter more fully described, so
that the pinion J in rolling off on this gear wheel K causes the gear wheel J* to
impart a rotary motion to the gear wheel I', thus rotating the shaft I.
A rotary motion can also be given to the shaft I from the shaft, G, so that the
speed of the pinion J³ rolling off the gear wheel I¹ is affected, and consequently
the speed of the feed shaft E, as the said pinion J³ is in the train of gear wheels
connecting the shaft E with the spindle B' as above described.
On the outer end of the shaft I is secured a gear wheel 12 in mesh with a gear
wheel N secured on a short shaft N' mounted to turn in suitable bearings formed
in a segmental arm N2 hung loosely on the shaft G and formed with a segmental
slot N engaged by a bolt N fastened on the frame and serving to secure the said
segmental arm N in place to hold the gear wheel in mesh with the gear wheel I.
On the inner end of the shaft N' is secured a gear wheel N in mesh with a gear
wheel N secured on the shaft G previously mentioned. Thus, when the shaft I is

page_text: rotated the gear wheel I' imparts a rotary motion to the gear wheel N to revolve
the shaft N which, by the gear wheel N', imparts a rotary motion to the gear
wheel No, thus rotating the shaft G, for running the carriage backwards by power.
But when the shaft G is rotated from the forwardly moving carriage as previously
explained then the said train of gear wheels connecting the said shaft G with the
shaft I rotates the latter to govern the speed of the pinion J' and that of the feed
shaft E. The segmental arm N' is made adjustable so as to permit of interchanging
the gear wheels I and N, according to the speed desired to be given to the feed
shaft E.
In order to control the gear wheel K from the handle E for the purpose above
described, I provide the following device:
On the inner end of the hub K' of the gear wheel K, is formed a conical
offset Kadapted to be engaged by a similarly-shaped friction collar O to press
the said offset K' in engagement with a conical recess A³ formed on the end of the
bed A, see Figure 2. The collar O is mounted to slide and is concentric with the
shaft I, the inner end of the said collar being engaged by a disk O' formed with a
handle O extending downwardly and adapted to rest against an offset A' formed
in a partition of the bed A, the said offset A' being the fulcrum for the arm O'
when the lower end of the latter is pulled inward to cause the disk O¹ to press the
collar O so as to clutch the offset K to hold the wheel K stationary.
In order to operate this clutch mechanism, I connect the lower end of the arm O
with a link provided with nuts O' engaging the outer side of the lower end of
the arm 02. The link Os is pivotally connected with a bell crank lever O³, (see
detail Figure 5) fulcrumed on the under side of the bed A. and pivotally-connected
by a link O with a crank arm P' held on a shaft P mounted to turn in suitable
bearings on the front side of the bed A below the shaft G, as plainly shown in
Figure 8. A sleeve P2 is mounted to turn with and to slide on the said shaft P
and is held between offsets extending from the carriage D, (see Figure 2) so that
the said sleeve moves forward and backward with the carriage without disengaging
the shaft P.
On the sleeve P2 is secured a crank arm P' pivotally-connected by a link P* (see
Figure 6), with a lever P fulcrumed at P on the outer end of the carriage D.
The upper end of this lever P' is formed with a slot P' engaged by an eccentric
pin P projecting from the outside of the hub E³ previously mentioned, so that
when the handle E of the said hub is turned a swinging motion is given to the
lever P³ which, by the link P and crank arm P³, imparts a turning motion to the
shaft P, whereby a swinging motion is transmitted by the crank arm P¹ and
link to the bell crank lever O' to exert a rearward pull on the lower end of
the arm to cause the disk O' to move the friction collar O forward to clutch
the offset K of the gear wheel K for the purpose above described.
When it is desired to give an ordinary feed to the carriage D for other than
screw cutting purposes, I provide the following device; the said feed being actuated
from the shaft G which is provided with a worm Qmounted to turn with and to
slide on the said shaft G (see Figures 2 and 7). This worm Q is held between
projections of the carriage D so that the forward and backward movement of the
latter carries the worm wheel forward and backward on the shaft, G without,
however disengaging the same. The worm Q is in mesh with a worm wheel Q¹
mounted to rotate loosely on the cone-shaped end F7 of the hub of the gear
wheel F³, the said worm wheel being adapted to be pressed in sufficient frictional
contact with the said end F', so as to rotate the gear wheel F' to cause a like
movement of the gear wheels F and F, whereby the latter on rolling off on the
rack F, imparts a sliding motion to the carriage D, the handle G7 being then in
an uppermost position. The worm wheel Q is pressed in contact with the end F7
by the head of the shaft F engaging the inner face of the said worm wheel,
and on the front end of the said shaft screws a nut F, to draw the said shaft F
outwardly, the said but abutting on the outer end of the hub of the gear wheel F.
By this arrangement the worm wheel Q' is locked to the gear wheel F' and rotary

page_text: motion given to the shaft is thus transmitted by the worm
wheel Qand wheels F', F and F³, as before described.
The operation is as follows':
to the worm
The gearing is arranged so that the lathe cuts a thread of a number per inch
which number is not a multiple of the number of threads per inch on the feed
shaft E. Now when the several parts are in the position, as illustrated in Figure 1,
and the spindle B' is rotated in the usual manner, with lever E' down and nut E
in engagement with feed shaft E, then the carriage D moves from the right to the
left and the tool C¹ cuts a thread on the work C. Now, when the tool is at the
end of the cut, the operator throws the lever E' up with his right hand so as to
disengage the nut E' from the feed shaft E, thus stopping further travel of the
carriage D, and consequently the tool C¹. The latter is now run out away from
the work in the usual manner and then the operator can return the carriage D by
hand on turning the lever F or he can throw the handle E' up so as to actuate the
clutch mechanism connected with the shaft I, whereby a rotary motion is given to
the shaft G in the direction of the arrow b₁, (see Figure 12) to cause a return
movement of the carriage D at a higher rate of speed than it had on the forward
one. When the carriage D has been run back sufficiently then the tool C' is again
run in to the beginning of the cut, after which the handle E' is again moved to its
regular lowermost position to connect the nut E' with the feed shaft E, it being
understood that the manipulation of the handle E again releases the clutch
mechanism on the shaft I, as previously described, so that the carriage D is again
moved forward with the tool in the cut, and at a speed corresponding to the
differential speed of the pinion J³ in mesh with the revolving gear wheel I' turned
by the gearing connecting the shaft I with the shaft G.
It will be seen that by this arrangement no backing belt or any other means
are necessary to catch the thread on the work C whether the said thread is or is
not a multiple of the number of threads per inch on the shaft E or an exact whole
number or any fractional part of a number of threads per inch, such as 11, 11,
10, 13, 13, etc. It is understood that when the lathe is in motion so that the
spindle B' rotates in the direction of the arrow c¹ in Figures 10, 11, 12, and 13,
the gear wheel L³, secured to the spindle B' through the gear wheels L' and L
imparts a rotary motion to the large gear J' so that the pinion J* is carried around
the gear wheel I'.
Now when the lever E' is up in a horizontal position so that the half nut E' is
disengaged froin the feed shaft E, the carriage D remains stationary so that the gear
wheel Fs in mesh with the fixed rack F must remain stationary also, and the gear F³
being connected by gearing as before described to the shaft G, the latter will remain
stationary also as illustrated in Figure 11. Then the shaft G being stationary and
connected by the gears N, N' and N to the gear wheel 12 secured on the outer end
of the shaft I, the latter must remain stationary, as illustrated in Figure 11, so that
the gear being stationary imparts a rotary motion to the gear Js by the latter
rolling off on the gear I' when the gear J³ is carried around the gear I by the
rotary motion of the gear J. The gear J³ being rotated in the manner above
described gives rotary motion through the gear J which is secured to the hub of
the gear J, to the pinion H7, the latter giving rotary motion to the feed shaft as
before described, in the right proportion to cut a number of threads per inch, that
is, a multiple of the number of threads per inch on the feed shaft, so that the
lever E can be thrown down so as to engage the half nut E' with the feed shaft E,
at any place, but when the lever E' is thrown down and the nut E¹ is in engage-
ment with the feed shaft E, the carriage D moves from right to left. The gear
wheel F being secured to a shaft F* mounted in bearings forming a part of the
carriage D, is moved with the carriage D along the rack F, the gear F³ rolling off
the rack F is caused to rotate, and the gear F through the gears F3 and G³, and
the beveled gears G and G¹, causes the shaft G to rotate, which, through the
gears No, N N and l'imparts rotary motion to the shaft I, so that when the
lever E' is down and the half nut is in engagement with the feed shaft E,

page_text: the shaft I is caused to rotate in the manner above described, and the gear wheel I'
being secured to the shaft I imparts. motion to the gear wheel J, in the right
direction and proper proportion to decrease the speed of the feed shaft E so as to
cut a finer thread according to the number of teeth in the interchangeable
gears N and I.
In case the carriage D in running back should strike the tail stock B³, the said
carriage will stop without any damage, as the change of motion is accomplished
by the friction clutch and no gear or gear wheels are thrown in or out of gear.
The advantage of this is that the tool can be thrown back or forward either by
the ordinary hand wheel of the ordinary lathe or it can be moved back or forward
by the same handle E that opens or closes the nut on the feed shaft, without the
operator being obliged to change the hand from the handle to the hand wheel, at
each stroke of the tool.
When the handle E is up and the nut E' is disengaged from the feed shaft, then
the latter is making the proper number of revolutions to cut a number of threads
per inch that will be equal to or a multiple of the number of threads per inch on
the feed shaft; therefore, the handle E can be thrown down and the nut closed
on the feed shaft at any place so that the tool will catch the thread in the
right place, but as soon as the nut is closed on the feed shaft the carriage D begins
to move forward and carries with it the gears in the carriage D, which are geared
into the rack F, so as to cause the gears to revolve as previously explained, it
being understood that the train of gear wheels is set in motion by the gear
wheel F rolling off on the fixed rack F as soon as the carriage D begins to
move. The feed shaft is thus caused to revolve in the right proportion to the
number of threads to be cut. By changing the gear wheels N and N more or less
speed can be given to the shafts E and G respectively, so as to cut a greater or less
number of threads to the inch on the work C in the lathe. By shifting the
lever G' the gear wheel G¹ can be moved out of mesh with the gear wheel G² so
that the rotary motion of the shaft G does not affect the train of gear wheels in
the carriage D. This is done when the lathe is not to be used as a screw cutting
lathe, but for ordinary work, it being understood that the gear wheels H and H¹
are then thrown out of mesh by shifting the arm H³ to the position shown in
Figure 9. A toothed block H³ fixed on the casing A then engages the gear
wheel H to lock the same, and cause the gear wheel J to roll off on the gear
wheel H. The shaft I is then rotated from the spindle B' in the inverse direction
of the arrow and a like movement is given to the shaft G while the shaft E
remains stationary. The worm wheel Qis then locked to the hub of wheel Fas
before described so that the shaft G by the worm Q, worm wheel Q', gear
wheels F, F and F and fixed rack F, causes the carriage D to travel on the
bed A. The beveled gear wheel G' has previously been moved out of mesh with
the beveled gear G' by the operator moving the handle G7 into an uppermost
position as previously explained (see Figure 13).
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is,
1. A screw cutting lathe, constructed and operating, substantially as shown and
described.
2. A screw cutting lathe, provided with a mechanism intermediate of the feed
shaft and the spindle, and provided with an auxiliary shaft driven from the moving
carriage, and geared with the feed shaft to cause the latter to rotate at a different
rate of speed than that otherwise given to the feed shaft by the spindle, substan-
tially as shown and described.
3. A screw cutting lathe provided with an intermediate mechanism between the
feed shaft and spindle, and comprising an auxiliary shaft, gearing for driving the
said shaft by the moving carriage, a second shaft geared with the said auxiliary
shaft, and a gear wheel secured on the said second shaft, and in mesh with a pinion

page_text: the gearing connecting the feed sa WIGH the spiune, sostamally as
and described.
4. A screw cutting lathe comprising a revoluble spindle, a feed shaft, gearing
for driving the said feed shaft from the said spindle, a carriage adapted to be con-
nected with the said feed shaft, an auxiliary shaft adapted to be driven from the
said carriage, a second shaft geared with the said auxiliary shaft, and a gear
wheel secured on the said second shaft and in mesh with one of the pinions of the
said gearing connecting the feed shaft with the said spindle, substantially as shown
and described.
5. A screw cutting. lathe comprising a revoluble spindle, a feed shaft, gearing
for driving the said feed shaft from the said spindle, a carriage adapted to be
connected with the said feed shaft, an auxiliary shaft adapted to be driven from
the said carriage, a second shaft geared with the said auxiliary shaft, a gear wheel
secured on the second shaft and in mesh with one of the pinions of the said gearing
connecting the feed shaft with the said spindle, a half nut held on the carriage and
adapted to engage the said feed shaft, and a lever for moving the half nut in or
out of engagement with the said feed shaft, substantially as shown and described.
6. A screw cutting lathe, comprising a 'revoluble spindle, a feed shaft, gearing
for driving the said feed shaft from the said spindle, a carriage adapted to be
connected with the said feel shaft, an auxiliary shaft, adapted to be driven from
the said carriage, a second shaft geared with the said auxiliary shaft, a gear wheel
secured on the said second shaft, and in mesh with one of the pinions of said
gearing connecting the feed shaft with the said spindle, a half nut held on the
carriage and adapted to engage the said feed shaft, a lever for moving the half
nut in or out of engagement with the said feed shaft, and clutch mechanism actuated
from the said lever and adapted to lock or release the said second shaft, substan-
tially as shown and described.
7. In a screw cutting lathe, the combination with a gear wheel adapted to be
driven from the spindle, of a shaft carrying a gear wheel, a pinion held on a stud
secured on the said driven gear wheel, in mesh with the said shaft gear wheel, and
a gearing for connecting the said pinion with the feed shaft to impart a rotary
motion to the latter, substantially as shown and described.
8. In a screw cutting lathe, the combination with a gear wheel adapted to be
driven from the spindle, of a shaft carrying a gear wheel, a pinion held on a stud
secured on the said driven gear wheel, in mesh with the said shaft gear wheel, a
gearing for connecting the said pinion with the feed shaft to impart a rotary motion
to the latter, a clutch gear wheel held loosely on the said shaft, a second pinion in
mesh with the said clutch gear wheel, the pinion being mounted on a stud of the said
first named driven gear wheel, and a gear wheel carrying on its face the last named
pinion and in mesh with the said shaft gear wheel, substantially as described.
9. In a screw cutting lathe, the combination with a gear wheel adapted to be
driven from the spindle, of a shaft carrying a gear wheel, a pinion held on a stud
secured on the said driven gear wheel, in mesh with the said shaft gear wheel, a
gearing for connecting the said pinion with the feed shaft to impart a rotary motion
to the latter, a clutch gear wheel held loosely on the said shaft, a second pinion in
mesh with the said clutch gear wheel, the pinion being mounted on a stul of the
said first named driven gear wheel, a gear wheel carrying on its face the last named
pinion and in mesh with the said shaft gear wheel, an auxiliary shaft, a second
gearing for connecting the first named shaft with the said auxiliary shaft, and a
third gearing connecting the auxiliary shaft with the carriage, substantially as
shown and described.
10. In a screw cutting lathe, the combination with a gear wheel alapted to be
driven from the spindle, of a shaft carrying a gear wheel, a pinion held on a stud
secured on the said driven gear wheel, in mesh with the said shaft gear wheel, a
gearing for connecting the said pinion with the feed shaft to impart a rotary motion
to the latter, a clutch gear wheel held loosely on the said shaft, a second pinion in
mesh with the said clutch gear wheel, the pinion being mounted on a stud of the

page_text: said first named driven gear wheel, a gear wheel carrying on its face the last named
pinion and in mesh with the said shaft gear wheel, an auxiliary shaft, a second
gearing for connecting the first named shaft with the said auxiliary shaft, and a
third gearing connecting the auxiliary shaft with the carriage, and a clutch
mechanism for controlling the said clutch gear wheel, substantially as shown and
described.
1000
J. H. PATERSON,
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agents.