IMPROVEMENTS IN GEAR CUTTING MACHINES
Year: 1883

page_text: LETTERS PATENT to Herbert John Allison, of the firm of Allison Brothers,
"
Patent Agents, of 41 Southampton Buildings, Holborn, in the County of
Middlesex, for an Invention of "IMPROVEMENTS IN GEAR CUTTING MACHINES
communicated to him from abroad by Ulrich Eberhardt and Henry
E. Eberhardt, residing at Newark, New Jersey, United States of America
COMPLETE SPECIFICATION filed by the said Herbert John Allison at the
Office of the Commissioners of Patents on the 19th June 1883.
HERBERT JOHN ALLISON, of the firm of Allison Brothers, Patent Agents, of
"IMPROVEMENTS
41 Southampton Buildings, Holborn, in the County of Middlesex,
IN GEAR CUTTING MACHINES," communicated to me from abroad by Ulrich
Eberhardt and Henry E. Eberhardt, residing at Newark, New Jersey, United
States of America.
This invention relates to an automatic feeding device for propelling a revolving
cutter through the rim of a metallic blank for cutting teeth thereon;
An automatic shifting device for turning the blank around a specific amount
before cutting each tooth;
And a locking mechanism for the latter, operated by the former, after each tooth
has been cut and the cutter retracted.
The feeding device consists in a screw provided with gearing to rotate it in either
of two directions, and a clutch provided with shipping devices for reversing the
motion of the screw at the proper point.
The device for rotating the blank a specified amount consists in a constantly
rotating friction driver operating upon the shifting gearing; and in a notched disk
and stop actuated by the movement of the cutter slide; the disk and stop operating
as the locking device.
This invention also consists in a toothed segment and worm applied to the
tipping table, for setting the cutter slide at various vertical angles; and in a screw
conveyor under the cutter, to remove the chips from the cutter slide
automatically

page_text: In the drawings, Fig. 1 is a sido elevation of a machine provided with these
improvements, Fig. 2 is a front elevation of the same, Fig. 3 is a plan of the samo
partly in section on line x, x, in Fig. 2. Fig. 4 is a vertical section of the machine
on line y, y, in Fig. 1; Fig. 5 is a vertical section of the clutch and gearing on
line,, in Fig. 1, and Fig. 6 is a longitudinal section of the gearing applied to
the end of the feeding screw, taken on line v, v, in Fig. 3. Figs. 2, 3 and 7 are
drawn on a smaller scale than Figs 1, 4, 5, 6.
The mechanism for carrying and moving the gear spindle A consists of an upright
square column B, spindle bearing O, carrying the worm frame D and adjusted
vertically by a screw and hand wheel E. The spindle is provided with a worm 1
wheel F and the frame D with bearings. supporting a worm and shaft G adapted
to turn the wheel F when the blank gear is to be shifted, as usual.
In machines, wherein this shaft is turned to shift the gear by hand, an auxiliary
shaft H is hung in bearings to the same framo, and a movable stud or frog I is
also secured to the same frame to carry an intermediate cog-wheel, which is 1
adjustable to the change wheels k, k¹ fitted to the shafts G and H to determine
the angular movement of the gear at each revolution of the auxiliary shaft.
The means for supporting the rotary cutter a is also that usually employed,
consisting in a bed 6 pivoted at its inner end to lugs o upon which the bed can be
turned in a vertical plane.
The lugs c are formed upon a plate d, which is pivoted by a vertical stud d¹
to a table d³ in the usual manner, so that the bed 6 may be moved in a hori-
zontal plane. The table d² is traversed horizontally toward the column B by a
screw d³
This bed has dovetail ways e formed in it, to guide the cutter slide fand is held
in the horizontal plane by bolts f4, and in the vertical plane by a toothed segment c¹
bolted to the bed b and provided with a worm c³ hung in a bearing o³ attached to
the table d².
The slide is provided with a screw g secured by collars in a lug at its front
end, and tapped into a nut i, which is fastened in a mortise in the bed b.
g
The mechanism, shown in the drawings for automatically turning this screw to
feed the cutter through the blank, consists in a worm and wheel, combined with
a pair of bevil gears, and a reversing clutch by means of which the screw is
alternately connected with the worm wheel to traverse the slide slowly forward
and with the bevil gear to move the slide and cutter quickly backward on the 3
completion of a cut.
The bevil gear is shown in the drawings as fitted loosely to the screw shank
next the front end of the slide f, and the worm wheel m is applied to the shank
at a suitable distance to admit the clutch n between them. The clutch is feathered
to the screw shank and is provided with teeth to engage similar teeth in either
wheel and the wheels being rotated by suitable means, in opposito directions, the
screw is turned in the desired manner by moving the clutch into contact with the
proper wheel, by a lever over the clutch and reversing mechanism. A guard p¹
is bolted to the slide and serves to cover the reversing gears and to carry portions
of the reversing mechanism.
To reverse the clutch automatically, a shifting lever n¹ is pivoted to a bearing
upon the guard p³, and a rod n² is secured thereto and extended along the side of
the slide and through a stud n³ secured to the front end of the bed b. The rod n*
is provided with two adjustable dogs n* and reverses the clutch at each end of the
stroke, with the aid of a spring stud o, arranged to press a roller r upon the top of t
the lever n', as shown in the section in Fig. 5, so as to carry the lever to the end
of its movement after the dog has brought it to its central position.
The spring stud is mounted in a vertical socket p secured at the top of the
guard (which is bolted to the front end of the slide f to cover the gears and m
and lever ) and is provided with a spring g at its upper end and has the roller r
pivoted in its lower end, as shown in Figs. 1 and 5.
By the clutch and shifting mechanism described, the cutter a and its traversing

page_text: slide faro automatically carried back and forth as required, feeding the cutter
slowly into the tooth and withdrawing it quickly.
The spindle K is shown provided with a pulley R to receive a belt for driving
the cutter in the usual manner, and a pulley S to operate the reversing mechanism
of the slide f
The gear
is driven by a pinion which is carried by a short shaft & mounted
in a bearing * bolted to the front end of the slide f.
The worm m³ and its shaft m¹ are similarly supported, and the shafts
are connected by a pair of cog-wheels m³ and m³ as shown in Figs. 2 and 5.
and m¹
A pulley m upon the shaft m' receives a belt from the pulley S, and thus
operates the reversing devices from the shaft K.
The pulleys S and m' and the gears m² and m³ may be proportioned to produce
any relative speed of the three shafts K, 13 and m¹ as required.
If preferred, the shaft 13 may be extended outside its bearing and be connected
with the spindle K by two sets of driving pulleys. These pulleys may be propor-
tioned to produce the fast and slow speeds desired, and a clutch applied to the
shaft between two of the pulleys can be operated to reverse the direction and
speed of the gear in the required manner.
The mechanism for shifting the gear spindle A. consists in a frictional driving
device operated by a belt or other continuous mover; in a graduated disk applied
to the shaft H or to a train of gearing connected therewith, and in a locking device
applied to the disk and operated by any suitable means after each tooth has been
cut and the cutter retracted.
The frictional driver is arranged to rotate the worm G continuously, except as
controlled by the locking device, determines the extent of such rotation accurately,
and thus secures a specific angular movement of the spindle A whenever the lock
is detached or unbolted. Several disks graduated differently, may be applied to
the shaft together, and the locking device be adjusted to either disk desired.
In the drawings, four disks, (lettered 1), are shown applied to a short shaft 2
mounted in the bracket 6 which carries the auxiliary shaft H, and is thus adjusted
with the latter at any height whenever the bearing C carrying the bracket 6 is
raised or lowered. In Figs. 1 and 2, the bearing is shown carrying a gear blank L
upon the spindle A, the whole being considerably raised above the cutter a to show
the latter more clearly.
The shafts 2 and H are connected by gears 3, and the latter shaft is also
provided with a bevil gear 4 which meshes with a similar gear 5 (carried by a
bearing 16 in the bracket 6) adjacent to the shaft H and at right angles to it in a
vertical line.
The friction driver consists in a friction pulley M connected by a pair of bevil
gears N to a shaft O which is secured at its lower end to the bevil gear 5, and slips
through the upper gear N with a feather when the bearing C and the disk-locking
devices are raised and lowered.
The shaft thus extends upward along the side of the column B, and the
pulley. M and gears N are carried in suitable bearings P. secured to the top of the
column.
A belt drives the friction pulley M continuously, but the shaft H being connected
to the disk by the gears 3, is prevented from rotating so long as the disk is locked,
and the pulley therefore revolves at such times without moving the gears N or
shaft O, by reason of such obstruction.
The disk may be provided with any desired number of holes or notches 15 in or
near its periphery, and is locked by means of a sliding bolt pressed into such
apertures by a spring.
The bolt is so operated that as soon as it is withdrawn from the disk it is
allowed to press again upon the surface of the latter between the notches, and
therefore arrests the disk by falling into the next notch to the one from which it
was drawn.
Should the disk be formed with two notches, it would therefore not make more

page_text: than half a revolution until unlocked again, and in like manner for any number
of notches.
It only remains, therefore, to form a connection between the locking bolt and the
reciprocating cutter slide, to render the angular movements of the worm wheel F
and gear blank L with the movements of the cutter a.
In Figs. 1, 2 and 3, the bolt 7 is shown guided in a bearing 8 secured to the
front end of the bracket 6, and projecting from the rear of the bearing, to which
bearing a spring 9 is attached to press the bolt toward the disk.
A pivoted button 10 is fitted to a notch 11 upon the rear of the bolt and is
mounted upon a lever 12, which is pivoted to an arm 13 at the lower part of the
bearing 8, so that the upper corner of the button will move in a curve when drawn
back by a chain 14 and slip out of the notch 11 when retracted sufficiently to
withdraw the bolt from the notches 15.
The button being pivoted at its centre to the lever 12, is adapted to enter the
notch 11 again by turning on its own pivot when the lever 12 is released from the
tension of the chain.
A spring 19 draws the lever toward the bearing 8, in opposition to the pull
of the chain, and a spring 18 upon the side of the lever tends to hold the button
in its normal position, by pressing the lower end of the button against the head of
the bolt in bearing 13.
The chain 14 is shown only in Fig. 1, and is attached at one end to the lever 12,
and by the other end to a hook 20 provided with a screw shank and mounted in
an arm 21 projecting from the bearing J.
By this chain a movement is conveyed from the reciprocating slide f carrying
the cutter a, to the spring bolt 7, at the end of each retracting movement of the
slide, when operated by the gear .
The screw upon the shank of the hook 20 is provided to adjust the length of
the chain to any desired degree below the length of a single link, as any link of
the chain may be hooked upon the hook when the slide is run back, to secure the
necessary movement of the lever 12 at that time.
When the slide is moved forward to cut a tooth, the chain is slackened, but is
tightened again at the end of each outward stroko to unlock the bolt 7 as
required.
Having thus described the construction of the feeding and gear-shifting devices
and the connection between the two formed by the chain 14; it will be perceived
that the gear-blank L can be turned any required amount by properly proportioning
the gears 3 and the change-wheels k and k². In practice the gear 3 upon the
shaft 2 has been made just three times the size of the gear 3 upon the shaft H,
which meshes into it, so that a third of a revolution of the shaft 2 or its attached
disk would cause the shaft H to make one exact revolution.
If the disk 1 were therefore provided with three of the openings 15, into which
the bolt 7 could fall, the shaft H would be rotated once for each reciprocation of
the cutter-slide and cutter.
When turned by hand, the shaft H is usually provided with a hand-crank
adjusted to a stationary stop upon the frame D, so as to set it exactly in its initial
position after each revolution; and the various coincident rotations of the worm
and shaft G are proportioned and effected by the use of change wheels applied as
shown at k, k¹.
Such a hand-crank is shown at U in Figs. 1 and 3, but is made detachable from
the shaft H, and when the latter is operated automatically as described, the change
wheels produce the same effect in turning the shaft Ġ as is effected in other
machines by the rotation of the hand-crank.
In like manner, when the hand-crank U is applied to the shaft H and the
bolt 7 is withdrawn from the notches in the disk, the shaft G may be rotated and
the gear-blank L changed in position, the same as in any machine having a hand-
crank and change-wheels.

page_text: The hand-crank is shown in the figures as fitted to the shaft H with a feather,
to secure a similar relation to the notches 15 when applied after a removal, and is
fastened thereon by a set screw a when required.
A spring tongue t is shown fitted into the back of the crank, to engage a notch
in a stop V which is shown in the plan in Fig. 3, and the front end of the stop
merely is shown in Fig. 1.
The stop V is secured to the bracket 6, and serves to secure an exact rotation of
the shaft H when turned by the crank as in similar machines.
To secure a movement of the shaft H, quarter or less than one exact rotation,
other disks may be applied to the shaft having less or more than three notches 15
therein.
Thus a disk with one notch would, with the gears 3 proportioned as above,
rotate the shaft H three times at each movement of the slide f and disk 1; a disk
with two teeth would rotate it one and one half times; one with four teeth, three
quarters of a revolution; one with six teeth one half a revolution; and so on for
other disks.
In Figs. 2 and 3.four disks are shown secured together upon the shaft 2, and the
bearing 8 is represented in Fig. 2 as secured to the front of the bracket 6 by a
slotted foot and bolt 22.
With this construction the bolt can be moved to coincide with any of the
four disks and the shaft 2 regulated by the number of notches provided in such
disk.
If desired, the disks 1 may be made detachable, and thus a disk with any number
of notches be applied.
The precise arrangement of the disk and bolt is immaterial, and the former
might be made with round. holes formed in its flat face and the bolt arranged to
stand at right angles to the plane of the disk and enter the holes to hold it in the
desired position.
It will thus be seen that the constructive features of this invention may be
somewhat modified without affecting the principle of the invention which consists
in the combination of the frictional device with the locking device, for operating
the gear shifting devices by power.
The friction pulley M by which the power is transmitted, is shown as having
an annular flange formed inside its rim, clamped between two disks secured by a
hub to the shaft of the gears N; but this structure is entirely immaterial, as any
equivalent device may be used to drive the shaft O, or either of the shafts 2 or Ĥ
by friction.
Thus a belt provided with a tightener, such as is commonly used to drive the
cutter in such machines, could be applied directly to the outer end of the shaft 2,
and arranged to drive a friction pulley thereon.
The belt would then continue to drive the shaft when the frame D and all the
locking mechanism was raised and lowered with the gear blank L, the same as if
the driving were affected by the shaft O.
The advantage of the latter is, that it is perfectly self-adjusting to all the
movements of the frame D and avoids any tightening device for the belt
employed.
In making a table or index to guide the operator in setting the change-wheels in
connection with the various disks required in this invention, one more column of
data would be required than where such disks were not employed, to express the
number of notches or openings required in the disk.
The use of the segment o¹ for tipping the bed b serves to lock the table in any
given position, as the teeth of the worm c² fit the segment closely; and the support
for the bearing c³ is shown in Figs. 1 and 3, where the bolt securing the bearing to
the table d' is indicated at c. The worm is provided with a hand wheel d³, by
which the table is adjusted at the angle required.
In Figs. 1, 3 and 4 is shown the conveyor for removing the chips that fall from

page_text: the cutter a upon the slide f, the bed b being provided with a trough ƒ¹ to catch
the chips as they fall.
A coarse threaded screw is inserted in the trough, as is shown at s¹ in Figs. 3
and 4 and indicated in parallel dotted outlines in Fig. 1; and a grooved shaft 8 is
fitted to a hole through the screw a¹ and extended to the front end of the slide f
where it is furnished with a pulley ƒ³.
A pulley f³ to drive the same, is shown at the front end of the screw g; and in
Fig. 2 the same are shown provided with a belt ³ to rotate the worm when the
screw revolves.
The front end of the shaft 8 is sustained in a bearing upon the side of the
guard p', and the bore of the screw &' is provided with a key in the usual manner,
to fit the groove or keyway 8 in the shaft s² and thus rotate the screw propeller as
the slide moves back and forth upon the bed b. to which the trough f¹ is attached.
The trough is formed with a discharging aperture e, shown in Fig. 3, and the
conveyor being rotated (by the proportion of the pulleys f" and f³) much faster
than the feeding screw g, the chips which fall in the trough from the cutter_are
steadily convoyed from the same as the cutter is operating. The screw s¹ is
reversed during the retraction of the slide ƒ but this is for a very brief interval,
and the cutter is not then producing any chips.
In Figs. 2, 6 and 7 is shown a latch t¹ applied to the top of the guard p¹, to
retain the clutch n in a central position between the gear wheels land m, that the
screw g may be turned by hand to set the slide and cutter as required in the
preliminary adjustment and. tosting of the gear to be cut.
The latch consists in a lever pivoted at one end, and formed with a notch to
engage a pin which is provided on the lever ; the pin t being projected from the
lever through a slot in the top of the guard or casing p¹.
If preferred, the end of the lever may be projected through the side of the
guard above the shaft bearing & and the latch & be applied to it at that point;
or other means be devised to hold the lever and clutch n in their central
position.
The means for rotating the conveyor screw s³ may also be varied by substituting
gear wheels for the pulleys f¹ƒ³; and such wheels or pulleys may be inserted
between the bevel gear 7 and its bearing on the slide if preferred to locating thom
in the exposed position at the front of the guard p', where toothed wheels would
be apt to catch the operator's clothing.
Having thus set forth the nature and operation of my improvements, I do not
limit myself to the precise construction and arrangement of the mechanism,
except when the same is a material and essential part of the invention, but
claim my improvements in their relation to the different parts of the machine to
which such improvements are respectively applicable, as follows:—
1st. The devices for imparting the to and fro or traversing motion to the
cutter slide f, and operating to advance it at a slow speed and retract it quickly,
as herein set forth; the same constituting an automatic feeding device for the
cutter as herein shown and described.
•
{
8
4
2nd. The devices. for automatically shifting.. the blank a specified amount, 4
substantially as shown and described herein, and operating for the purposes set
forth.
3. The combination, with the automatic shifting devices constructed with a
locking bolt as, described; of a connection, as chain 14, to the reciprocating cutter
slide f; for the purpose of drawing out the locking bolt when the cutter is retracted 5
from the blank, substantially as herein set forth.
4th. The devices, consisting of a toothed segment and worm operating as
described; for tipping the table carrying the cutter slide, as herein shown and
described.
5th. The devices for removing the chips that fall from the cutter, consisting 5
in the trough and screw. conveyor arranged and operated-substantially as set
forth.

page_text: 6th. The gear cutting engine consisting of the parts constructed and combined
substantially as shown in the drawing and operating as and for the purpose set
forth.
In witness whereof, I, the said Herbert John Allison, have hereunto set my
hand and seal, this nineteenth day of June in the year of our Lord one thousand
eight hundred and eighty-three.
HERBERT. J. ALLISON. (L.S.)