Improvements in Machine for Cutting Toothed Wheels.
Year: 1897

page_text: Date of Application, 19th Jan., 1897
PROVISIONAL SPECIFICATION.
Improvements in Machine for Cutting Toothed Wheels.
I, ULRICH EBERHARDT, of No. 97, New Jersey Railroad Avenue, in the City of
Newark, County of Essex, State of New Jersey, U.S.A. Engineer and Machinist,
do hereby declare the nature of the said invention for IMPROVEMENTS in MACHINE
FOR CUTTING TOOTHED WHEELS to be as follows:-
:―
The present invention relates to that class of gear cutting engines in which the
driving pulley is rotated continuously, and operates intermittingly and automati-
cally through a friction device upon a train of change wheels to turn the blank
into successive positions for cutting a series of teeth therein.
In this class of machines the cutter is reciprocated to and from the blank by a
cutter-head actuated by a feed screw, with suitable clutch mechanism to reverse its
rotations automatically, and the present invention furnishes a safety-stop of par-
ticular construction for holding such clutch mechanism in a neutral or inoperative
position until the blank is properly rotated, to avoid the cutting of the same at
an improper point.
The invention also furnishes an improved connection between the change wheels
and the cutter spindle for use in hobbing, a single shaft being connected by de-
tachable gears directly with the change wheel arbor and the cutter spindle, the
arrangement being such as not to interfere with the operation of the safety-stop
when cutting spur gears.
In the present invention a truly circular stop-disk, having a notch in the edge,
is rotated with the change wheels, and the lever or clutch shifter which is employed
to shift the clutch for reversing the cutter feed is suitably connected with a pawl
fitted to the notch in the stop-disk, and, when drawn from such notch to permit
the rotation of the change wheels and the blank, rests upon the circular periphery.
of the stop-disk and thereby holds the clutch-shifter in a neutral position through-
out the entire rotation of the disk, until the tooth re-enters such notch.
The pawl is retracted from the stop-disk by a suitable attachment to the cutter
head, as the latter is withdrawn from the last-finished cut in the blank.
The feeding of the cutter-head is thus positively prevented until the blank is
shifted the required amount.
The stop-disk is preferably provided with a cam, adapted, by pressure upon an
arm, to force the pawl into the notch to positively arrest the disk.
The connection between the pawl and the clutch-shifter is preferably formed to
lock the clutch-shifter positively in a neutral position until the pawl enters the
notch in the disk, and such locking device consists of a stop-rod reciprocated by
the pawl, and a slide linked to the clutch-shifter and having a projection to engage
the stop-rod.
The stop-rod thus serves to lock the projection and to prevent any accidental dis-
placement of the clutch-shifter until the pawl enters the notch in the disk upon the
completion of the blank's movement.

page_text: It is common in such gear cutting engines to sustain the change wheels and
their connections upon the mandrel-head which carries the blank, and is adjust-
able to and from the path of the cutter, for operating upon blanks of different
diameters, and the pawl is in such cases connected with the stop-rod by adjustable
mechanism; so as to properly operate the same, in various positions of the mandrel
head.
To adapt such a machine for hobbing or forming worm-teeth in the blank by
means of a worm cutter, the spindle of the cutter-head upon which the worm cutter
is mounted is connected with one of the change wheels by a single hobbing shaft
with bevel or miter gears at its opposite ends.
The gears are detachable at one or both ends of the shaft, to permit the removal
of the same when the machine is used for cutting spur gears. To facilitate the
removal of the cutter spindle and the application of different cutters thereto, the
hobbing shaft is preferably connected indirectly with such spindle. To effect
such indirect connection, a stud is mounted upon the cutter-head adjacent to the
spindle bearing, and a spur gear is fitted to the spindle, and an auxiliary spur gear
is fitted to the stud, and the hobbing shaft is connected with such auxiliary gear by
swivel bearings and bevel gears so as to transmit the rotary motion to the cutter-
spindle throughout the various movements of the cutter-head.
With this construction, the cutter, spindle can be removed from its bearings with
its own spur gear, without detaching the auxiliary gear from the hobbing-shaft
and the restoration of the cutter spindle to its bearing tlius connects the spindle
with the auxiliary gear.
I
COMPLETE SPECIFICATION.
Improvements in Machine for Cutting Toothed Wheels...
I, ULRICH EBERHARDT, of 97, New Jersey Railroad Avenue, in Newark, County
of Essex, State of New Jersey, U.S.A., Engineer and 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 present invention relates to that class of gear-cutting machines in which
the driving-pulley is rotated continuously and operates interimittingly and auto-
matically upon a train of change-wheels to turn the blank into successive positions
for cutting a series of teeth therein; and in which the change-wheels are some-
times connected directly with the cutter-spindle; so as to rotate the same in unison
with the blank when "hobbing" or cutting worm-teeth in the same..
.
In this class of machines the cutter is reciprocated to and from the blank by a
cutter-head actuated by a feed-screw, with suitable clutch mechanism to reverse
its rotations automatically, and tlie present invention furnishes a safety-stop to
hold such clutch mechanism in a neutral or inoperative position until the blank
is properly rotated; and thus avoid the cutting of the same at an improper point.
The invention also furnishes an improved connection between the change-wheels
and the cutter-spindle for use in hobbing: a single shaft being connected by de-
tachable gears directly with the change-wheel arbor and the cutter-spindle, the
arrangement being such as not to interfere with the operation" of the safety-stop
when cutting spur-gears..

page_text: The invention will be understood by reference to the annexed drawings, in which
Fig. 1 is a plan of a gear-cutting machine with certain well-known parts omitted
which are not required to illustrate the invention. Fig. 2 is a side elevation of
the same; Fig. 3, an end elevation of the feed-clutch shifter; Fig. 4, is a plan of
the stop-shaft and its attachments. Fig. 5, is a diagrammatic elevation of the
same upon the inner side; Fig. 6, a front view of the same; Fig. 7, a diagram
of the stop-wheel with grooved cam to control the pawl; Fig. 8.a vertical section of
the hobbing connections for the cutter-spindle, and Fig. 9 a longitudinal section of
the gear-box for the hobbing-shaft. Fig. 10. to 13 inclusive. show details, somewhat
enlarged.
The improvements are illustrated upon a style of machine already well-known.
A designates the bed of the gear-cutter frame, and D a carriage or cutter-head
fitted to ways upon the top of the bed. The cutter-head is provided, as shown in
Fig. 1, with a central opening to receive the cutter u, at the opposite sides of which
are bearings Y¹ for the cutter-spindle Y.
A feed-screw a is secured to the carriage D and projected through a rotary nut
b, mounted in bearing b¹ at the outer end of the bed, and provided with a feed-gear
c at its outer end.
The gear c is driven automatically in opposite directions by two trains of gear-
ing connected with a feed-shaft L, which is driven by shaft J, mounted at the
rear end of the machine with a pulley J2 thereon.
The clutch-hub c¹, which connects the two trains of gearing alternately with the
rotary nut b, (through the gear e) is shifted, by a clutch-fork g which is mounted
upon the shaft gl, having upon its outer end a shifter-arm g².
This reversing-gearing for the feed-screw, with its clutch mechanism, is enclosed in
the casing N, from one side of which the shaft g¹ projects to receive the shifter-
arm.
A stud 9 is projected from the top of the arm and a hook or latch q¹ shown
in Fig. 2, is pivoted upon the casing N adjacent to such arm and so adjusted to
the stud that when hooked thereon it holds the clutch-fork in a central position.
when required to prevent the operation of the feeding devices.
A trip-lever n is pivoted upon the shaft g¹ and shifted by the carriage D to
actuate the shifter arm.
The
The trip-lever is oscillated by the stop-rod P and dogs P¹, actuated by a lug P2 upon
the carriage, and is provided with a radial spring-bolt 1, having wedge-faced face
adapted to operate with a stationary wedge-block; to shift and hold the trip
lever alternately at opposite sides of its central position in the usual manner.
trip-lever is provided with lugs to press upon the opposite sides of the shifter-
arm the space betwen the lugs being made wider than the arm, as shown in
Fig. 10; and adjacent to the left hand lug in Fig. 11, to permit the bolt to
move past the centre of the wedge before the clutch becomes engaged; thus
securing the engagement of the clutch, as is common in such reversing operations.
The latch
1 is omitted from Fig. 1 to avoid obscuring the trip-lever and shifter-
arm, but is shown in Figs. 2 and 12 engaged with the stud 9 upon the shifter-arm,
5 to hold the clutch-fork in a central and inoperative position... It is shown in
opposite position in Fig. 10.
q
designates the column carying the mandrel-head F, provided with the mandrel-
shaft A, having upon its rear end a worm-wheel H.
The pulley Ja is connected by gears K and friction device I2 with the worm.I¹
0 to rotate the mandrel A¹ and the blank intermittingly.
It will be understood that the friction device or disk is fastened, as is common in
such machines, to the shaft upon which it is mounted, while the gear K is fitted
to turn upon the shaft and rotates the same only by frictional contact with the
disk 12.
The rotation of the shaft I is controlled by the stop-disk (hereinafter described)
and its attachments, and is constantly impelled to rotate by the revolving pulley,
J and the friction device I².

page_text: .
A frame G¹ is fixed to the rear end of the head F and provided with bearings
carrying worm-shaft I with worm I¹ to drive the wheel H.
The frame G supports a bracket G2, upon which are mounted the stop-shaft
S and an adjustable stud S¹ for carrying intermediate change-wheels S. The
worm-shaft I is connected with the stop-shaft S (through the intermediate wheels
S by the change-wheels I³.
The bracket G2 and all of the stop mechanism are shown in detail in Figs. 4 to 7
inclusive, but the bracket and the bearings upon the same are indicated only by
dotted lines in Fig. 2, so as to exhibit clearly the parts in the rear of the same.
A casting, as shown in Figs. 4 and 6, is secured upon the bracket G³ and provided
with bearing C for the stop-shaft, bearing C₁ for the stop-pawl, and bearing Ca
for the pawl-detent.
A stop-disk d is formed with circular periphery having a notch d¹ in the edge
and secured upon the stop-shaft with the cam d2 at one side of the same.
The stop-pawl is provided with a tooth e to engage the edge of the notch
with an arm f to engage a cam for pressing the tooth into the notch.
and
The pawl serves, normally, by engagement with the side of said notch, to inter-
mittingly regulate the rotations of the change-wheels to shift the blank through
a definite angle, and the detent h is connected by an adjustable chain ? with the
lug P upon the cutter-head 1) to pull upon the detent and draw the pawl from the
notch dat each outward stroke of the cutter-head.
The detent is fitted movably by a shank to a pivoted arm h³, which is drawn
backward, normally, by a spring and is provided with an eye h² to receive the
chain or rod for pulling the detent. The eye is omitted from the arm h³ in
Fig. 5, as the latter figure is designed simply to illustrate the coaction of the
detent, the pawl, and the stop-disk. As the change-wheels perform their entire
function during one rotation of the stop-disk, it is essential that the pawl should
be released by the detent before such rotation is completed, and such release is
effected by forming a cam-shaped groove in the periphery of the disk and pro-
jecting a toe i from the pawl into such groove, the bottom of which is extended
to the edge of the disk, so as to force the detent upwardly and release the pawl
as soon as the disk has made a partial rotation.
The detent is thus wholly cleared from the pawl, and the latter left free to en-
gage the notch d¹ before such notch can by any possibility be turned past the
pawl.
The detent when disengaged from the arm is pressed outwardly (by a spring
beneath the shank) to a suitable point to catch upon the tip of the pawl, as shown
in Fig. 7, being pressed inwardly to slip over the tip of the pawl, as shown in Fig.
5, when the tension upon the eye h³ is released and the detent is drawn backward
by the spring h¹.
The pawl is also provided with an arm e¹, connected by link M with a loose
collar m upon a stop-rod N.
The rod N is mounted vertically at the side of the column E in bearings N₁
and N2, and a stop-slide o is fitted to bearings at the side of the bed and connected
by a rod or link with the clutch-shifter arm g².
The slide o is arranged beneath the stop-rod N and provided with a projection
or block o, which bears against the side of the stop-rod when the shifter-arm is
in the central position and the feed-clutch inoperative. One of the trains of feed-
gearing is so arranged that the stop-rod must be raised to permit the movement
of the slide o before the clutch can be engaged to feed the cutter forward after
each shift of the blank.
The cutter-head D is shown in Fig. 2 at the end of its outward stroke in readi-
⚫ness to feed forward, and its previous outward movement shifts the trip-lever na
little past its central position, as shown in Fig. 2, in readiness to automatically
push the shifter-arm in the same direction (under the pressure of the spring-
bolt when the shifter-arm is released from the restraint of the slide o.
A spring n² is fixed to the bracket G2 and the link M to press the stop-rod nor-
.

page_text: As the pawl is governed
nally upward by contact with a dog m¹ upon the same.
y the notch in the disk d, the stop-rod can only be lifted and the slide o released
when the pawl is resting within such notch.
A cam, (shown in Figs. 2 and 5) which covers a section only of the circle,
operates upon the arm f when the pawl approaches the notch di, as shown in
Fig. 5, and the pawl is at other times supported by its connection with the rod N,
which is then resting upon the slide o.
When the motion of the stop-disk is, by any defective operation of the
mechanism, arrested before its completion, its circular periphery prevents the
pawl, as shown in Fig. 5, from moving towards the stop-shaft, and the stop-rod
then prevents the movement of the clutch-shifter, as desired.
When the stop-disk is normally rotated, as shown in Fig. 1, the arm e¹ lifts the
stop-rod N to clear the corner of the block o³, and the slide is then moved later-
aily, as indicated in dotted lines in Fig. 2, by the operation of the spring-bolt!
upon the shifter-arm g². Such motion clutches the nut b to the proper train of
gearing and propels the carriage forward into the blank until its movement is
reversed by the dog P¹. (Shown in Fig. 1.)
A slightly different cam connection is shown in Fig. 7, where the pawl is pro-
vided with an arm having a pin f¹ fitted to a groove in the face of the stop-disk d,
such cam-groove holding the pawl adjacent to the edge of the disk and pulling
the tooth at the required time into the notch to arrest the disk. With this
construction it is obvious that the entire motion of the pawl is effected by the cam
connection, and that the pawl is therefore more positive in its action than when
moved in one direction by a weight or spring.
Either of the cam connections operates to force the tooth e positively into the
notch as the notch turns toward such tooth. The cam is so shaped adjacent to the
notch das to permit the movement of the arm with the pawl, when the detent
is pulled to detach the pawl from the notch near the outer end of the cutter-
head's motion, which permits the change-wheels to rotate the blank before the
cutter-head is fed forward. The essential feature of this part of the invention con-
sists in the positive movement of the pawl by means of a cam rotated with the
stop-disk, to force the pawl-tooth into the notch upon the disk, and thus
absolutely prevent the disk from rotating past the desired point.
In machines of this class the worm-shaft I and the change-wheels are rotated
by friction-gearing, which continues to actuate such wheels and to rotate the blank
until their motion is arrested by the stop mechanism, and this device secures
positively the checking of such motion when the blank has been rotated through
the required arc. The stop-rod and its control by the position of the pawl, which
holds the clutch in a neutral position until the stop-disk is fully rotated, also
positively secures the clutch from movement until the disk is fully rotated, and
the intermittent movement of the blank is thus effected with absolute certainty.
The form of the cam which moves the pawl-tooth into the notch upon the stop-
disk is immaterial, as also the precise construction and arrangement of the stop-
rod which connects the pawl detachably with the clutch shifter.
It is very desirable that machines of this class should be provided with a direct
connection between the worm-shaft I and the cutter-spindle Y, so that they may
be adjusted to rotate in unison when hobbing or cutting worm-teeth upon the
blank. The present construction is therefore provided with such a hobbing attach-
ment, the hobbing-shaft t being shown in Fig. 1 connected with the stop-shaft S,
and the spindle Y provided with a hob or worm-cutter u.
A bearing v for the shaft is fitted by a swivel-collar vl to the stop-shaft and
the shafts are connected by bevel-gears 2, and the shaft is fitted to slide longi-
tudinally through a bearing V, which is swiveled upon a stud a¹, attached to the
cutter-head D, adjacent to the spindle Y. A part only of the shaft t (with the
5 bearing V) is shown in Fig. 2, so as not to obscure the safety-stop mechanism.
A gear-wheel is secured to the outer end of the spindle Y, and an auxiliary
gear-wheel (meshing therewith) is fitted to the stud u¹, and bevel wheels w²

page_text: ¡connect the wheel with the hobbing-shaft t, which is fitted by a spline to
the wheel 2, through which it passes, such wheel, as shown in Fig. 9, being
furnished with a sleeve to rotate in the bearing V. The spline or key x is secured
removably in the sleeve and is fitted to a key-way in the shaft t, thus forming
the splined joint to rotate the bevel-wheel with the shaft when required.
When the hobbing device is not required for use, the key may be removed,
thus permitting the hobbing-shaft to rotate without affecting the cutter-spindle.
The wheel w may, if preferred, be made detachable from the cutter-spindle, as
it is immaterial what gear-wheel be removed or rendered inoperative to disconnect
the hobbing-shaft and spindle. The bearing is provided with a casing V to
enclose the wheel 2 and is swiveled to the stud u¹ by means of a shank al, which
is projected from the casing through the stud and secured upon the inner end of
the latter by a screw and washer 3. The stud is shown connected by bracket X
with the bearing of the cutter-spindle, but it is immaterial how the stud or
Auxiliary wheel be supported.
The hobbing shaft is connected with the auxiliary wheel w¹ instead of with the
wheel upon the cutter-spindle to permit the manipulation of the cutter-spindle
Y, which is required in applying and removing various kinds of cutters, so formed
upon the top as to permit the withdrawal of the spindle Y with the gear-wheel w
when it is necessary to change the cutter or hob upon the spindle. The wheel
w is shown fitted removably upon the end of the spindle, so that it may be removed
when the hobbing attachment is not in use, and the gear thus forms a direct
detachable connection between the cutter-spindle and the hobbing-shaft.
I have made special claim herein to a cam-groove rotated with the stop-disk, and
a projection from the pawl fitted to such groove, so as to effect the entire motion of
the pawl by the cam, as such construction secures a positive action of the safety-stop
device, and obviates any of the uncertainty that exists in the use of weights or
springs to partially control the movement of the pawl.
From the above description it will be understood that I do not claim a safety-
stop for the cutter-head of the gear-cuting machine, but the combination, with the
other elements, of a stop-disk having a circular periphery with notch in the edge,
and a pawl which is adapted to hold the clutch-shifter in a neutral position through-
out the entire rotation of the stop-disk and to permit the clutch-shifter to operate
only when the pawl-tooth enters the notch in the disk.
The stop-disk in such machines, by its connection with the change-wheels,
revolves with considerable rapidity, and the time required for the pawl-tooth to
enter the notch is very small but the clutch-shifter is held stationary during the
time that the pawl-tooth enters such notch and is released only at the end of such
movement by the interference of the stop-rod N with the movement of the stop-
slide, which is prevented from motion until the stop-rod is drawn wholly away
from the block or projection upon the slide. The feed is thus positively pre-
vented from operating and the cutter from penetrating the blank unless the stop-
disk is completely rotated and the blank fully shifted into the required position
for operation.
I have made no broad claim herein to a safety-stop upon the cutter-head of a
gear-cutter, as such stops have long been used, but my device is intended to secure
this object with more certainty than others, and is more simple in construction
than anything that has (within my knowledge) been previously used for the same
purpose.
Having now particularly described and ascertained the nature of the said in- 5
vention and in what manner the same is to be performed, I declare that what,
I claim is:-
J. In a gear-cutter, the combination, with a cutter-head, and reversing-gear
having a clutch-shifter, of change-wheels and a stop-disk rotated thereby. and
having a circular periphery with notch in the edge, and a pawl suitably connected
to the clutch-shifter and provided with a tooth to engage the notch, and adapted

page_text: to rest upon the circular periphery of the stop-disk, and to thereby hold the clutch-
shifter in a neutral position throughout the entire rotation of the disk until the
tooth enters such notch, substantially as herein set forth.
21
2. In a gear-cutter, the combination, with a cutter-head and reversing-gear
having a clutch-shifter, of change-wheels and a stop-disk rotated thereby, and
having circular periphery with notch in the edge, a pawl suitably connected to
the clutch-shifter and provided with a tooth to engage the notch, and with the
arm f, and a cam rotated with the stop-disk and adapted by pressure upon the
arm to force the pawl-tooth into the said notch to positively arrest the disk, sub-
stantially as set forth.
3. In a gear-cutter, the combination, with a cutter-head and reversing-
gear having a clutch-shifter, of change-wheels and a stop disk rotated
thereby and having circular periphery with notch in the edge, a
pawl with tooth to rest upon the edge of such disk and engage the notch,
a stop-rod controlled by said pawl, and a slide linked to the clutch-shifter and
having a projection to engage the stop-rod the whole arranged and operated sub-
stantially as herein set forth.
4. In a gear-cutter, the combination, with a cutter-head and reversing-gear
having a clutch-shifter, of the mandrel-head F with change-wheels and stop-disk
carried thereby, a vertical stop-rod supported adjacent to the stop-disk, a hori-
zontal slide connected with the clutch-shifter and provided with a projection to
engage the stop-rod and a link to move the same with the pawl, and an adjustable
dog upon the stop-rod to contact with the loose collar in various positions of the
mandrel-head, substantially as herein set forth.
5. In a gear-cutter the combination, with a cutter-head and reversing gear
having a clutch-shifter, of mandrel-head F with change-wheels and stop-disk
carried thereby, a vertical stop-rod supported adjacent to the stop-disk, a hori-
zontal slide connected with the clutch-shifter and provided with a projection to
engage the stop-rod, a pawl fitted to bear upon the edge of the stop-disk, a loose
collar upon the stop-rod, a link to move the same with the pawl, an adjustable dog
upon the stop-rod to contact with the loose collar in various positions of the
mandrel-head, and a spring applied to the link to balance the same and normally
lift the stop-rod, as and for the purpose set forth.
6. In a gear-cutter, the combination, with the bed A, column E, and mandrel-
head provided with frame G¹ carrying the worm-spindle I, change-wheels, and
stop-shaft S, of putter-head D provided with cutter-spindle Y, and a single
hobbing shaft connected at its opposite ends by suitable gearing to the contiguous
ends of the stop-shaft and cutter-spindle, substantially as set forth.
7. In a gear-cutter, the combination, with the bed A, column E, and mandrel
head provided with frame G¹ carrying the worm-spindle I, change-wheels, and
stop-shaft S, of cutter-head D provided with cutter-spindle Y, and a stud adjacent
to the spindle, a gear upon the spindle and an auxiliary gear upon the stud, and
a hobbing shaft connected with the stop-shaft and with the auxiliary gear upon
the stud by swivel-bearings and bevel-gears, substantially as herein set forth.
8. In a gear-cutter, the combination, with a cutter-head and reversing-gear
having a clutch-shifter, of change-wheels and a stop-disk rotated thereby and
having notch in the edge, a pawl suitably connected to the clutch-shifter and pro-
vided with a tooth to engage the notch, a detent pivoted adjacent to the pawl and
provided with a spring shank, a connection from the detent to the cutter-head
to pull the detent, and a cam rotated with the stop-disk and operating upon such
detent to detach it from the pawl before the disk has completed one revolution,
substantially as herein set forth.
9. In a gear-cutter, the combination, with a cutter-head and reversing-gear
having a clutch-shifter, of change-wheels and a stop-disk rotated thereby and
5 having circular periphery with notch in the edge, a pawl suitably connected to
the clutch-shifter and provided with a tooth to engage the notch, a cam-groove
rotated with the stop-disk, and'a projection from the pawl to engage such groove

page_text: the entire motion of the pawl being effected by such cam, and the clutch being
thereby held in a neutral position until the disk is wholly rotated, substantially
as herein set forth.
1
1
Lo 1007
THOMAS S. CRANE,
10 Wall Street, New York City,
Agent for Applicant.