Improvements in or relating to Machines for Cutting Helicoidal. Teeth on Wheels.
Year: 1899

page_text: Date of Application, 11th Dec., 1899-Accepted, 19th May, 1900
COMPLETE SPECIFICATION.
Improvements in or relating to Machines for Cutting Helicoidal.
Teeth on Wheels.
I, LEON FRANÇOIS ACHILLE MONNERET, Engineer, of 169, Rue d'Alésia, Paris, in the
Republic of France, 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 :-
Theory and practice alike have demonstrated the fact that, as regards gear wheels,
helicoidal teeth produce a more easy and even motion than the straight cut teeth.
This is easily explained when it is remembered that, as regards straight cut teeth,
each tooth acts by coming successively into the plane of contact, whereas, in the case
of teeth cut in helicoidal form the tooth comes in contact with this plane progressively
as regards each of its portions.
Moreover, in the case where the axes are contained in the same plane, such cases
being of especial interest in the present case, the friction in helicoidal toothed gear
is less than in straight cut toothed gear, and especially with regard to conical gear
wheels; the question of thrust on the bearings does not occur in the case of helicoidal
gear wheels.
A conical pinion with helicoidal teeth is therefore always preferable to a conical
pinion with straight cut teeth, and can be advantageously substituted for it in all
cases.
On the other hand the continued rise in the cost of skilled manual labour make
the employment of automatic machines which can be attended to by more or less
unskilled attendants, a great desideratum, and especially from the point of economy,
machines, which do not require the use of a great number of similar parts would be
of advantage.
For these reasons I have devised a machine which will automatically cut helicoidal
conical teeth, which machine forms the subject matter of the present invention.
In the accompanying drawings I have represented such a machine by way of
example only.
Figure 1 is a longitudinal elevation of the machine.
Figure 2 is a plan of the machine represented in Figure 1.
Figures 3 and 4 are elevations of opposite ends of the machine.
Figure 5 is a vertical longitudinal section along the principal axis of the machine.
Figure 6 is a cross section on the same principal axis.
Figure 7 is a plan view partly in section, and
Figures 8-12 are diagrammatic views intended to facilitate the understanding of
the theoretical and practical principles involved in the designing and construction of
the machine.
The machine is based on the two following general principles:-
1st. The principle of the mechanism giving to the tooth the form of an involute
of a circle.
2nd. The principle of the mechanism according to which the tooth is cut in the
form of a helix, while at the same time the division of the tooth is carried out.
We will examine these two principles separately and finally describe the means by
which the principles may be carried into effect.

page_text: THE MECHANISM BY MEANS OF WHICH THE TOOTH IS CUT IN ACCORDANCE WITH THE
INVOLUTE.
This mechanism is naturally based on the properties of the curve named the
involute of a circle. It is known that two wheels of the same pitch cut according to
an involute will always gear with each other whatever be the number of their teeth.
If we consider the limit-wheel of conical wheels for which the demi-angle at the
vertex is 90°, all wheels which will gear with the latter will gear with each other.
It should be remembered that the complementary cone of this limit wheel being
infinite the shape of the teeth will be the same as that of the teeth of a rack bar, i.e.,
they will be formed by straight lines as represented in Figure 8.
It is therefore sufficient to gear the pinions to be cut with the limit wheel by
giving them the movement which they would have if they were to gear together, in
order that this limit wheel should cut on the pinion being made a tooth in the form
of an involute.
Evidently the same result would be obtained if instead of an actual limit wheel a
simple tool were employed for cutting the teeth the straight flanks of which are
easily traced and which could be so worked as to generate the surface of the limit
wheel itself. In other words the tool is given a rectilineal movement directed
towards the apex of the cone of 'the wheel to be cut, and it will generate a tooth of
the limit wheel to which is communicated the movement of rotation suitable to gear
with the pinion to be cut in such a manner as if gearing practically took place.
Leta (Figure 8) denote the half angle at the apex of the primitive cone of the
pinion about to be cut; then the ratio of the angular speeds (Va) to be given to
the tool, on the one hand, and of the pinion to be cut on the other hand, is given by
the following equation
:-
Speed of the point M = M P x Va of the ninion
MOX Va of the tool
It will be shown, further on, how this ratio of the speeds is secured.
Of course it is evident that only one side of the tooth is cut at a time and that the
second side is obtained in the same manner after the pinion has been moved to an
extent corresponding to the width of the space between the teeth.
THE MECHANISM FOR GENERATING THE TOOTH IN THE SHAPE OF A HELIX AND
AT THE SAME TIME EFFECTING THE DIVISION.
The helicoidal form of the tooth is obtained by making use of the automatic
division of the tooth in the following manner :-
The pinion has a continuous turning movement round its axis and the tool has an
alternate rectilineal movement. The connection of the two movements is obtained
by means of a four-wheel gearing which are so combined that the number of turns
of the device for giving the tool its rectilineal movement is to the turns of the pinion
in proportion to the number of teeth to be cut; in other words if the pinion is to
have n teeth the tool will make a complete movement, to and fro each time that the
pinion turns of a revolution. Inasmuch as these two movements are mathe-
n

page_text: matically unalterable, and continue without stop or backward return, the result is
that the division is absolutely correct, the tool making successively a full stroke on
each of the teeth.
It will also be understood, on the other hand, that the tool describing in its
course a generatrix terminating at the apex of the cone while the pinion is turning
round itself in a continuous manner, will describe on the pinion a helicoidal curve
the inclination of which only depends on the number of teeth and the course of the
tool.
Hence the operator will not have to trouble about the helicoidal movement, which
will be produced by itself, automatically, by mounting the gearing appropriate for
the number of teeth to be cut, and by regulating the course of the tool, the latter
depending on the length of the tooth.
When the operator is cutting the second pinion which is intended to gear with the
first cut pinion he will in no way alter the course of the tool, since the length of the
tooth remains the same. He will simply mount the set of gearing according to
the number of teeth of this second pinion and he will change the direction of the
helix by a simple movement of the handle of the actuating mechanism, which pro-
duces the necessary alteration of travel.
Under these conditions the two pinions cannot fail to gear with each other. One
will have its helix directed to the left while the other as is necessary has it directed
to the right. Moreover, the different points of the two helices will be in contact
with each other at every moment or point of movement. It will now be shown that
the two helices are in contact at every moment of the movement; since :-
1. On a common generatrix the two helices have a common point.
2. The two tangents at this point of the two helices coincide.
If c represents the course or travel of the tool and n the number of teeth to be
cut, the helicoidal path on the generatrix of the one is represented by :—

page_text: n
D
It will be observed, that, inasmuch as, in the case of two conjugate pinions A, c, and
are constants for the same value of 4, the value of will also be the same, hence
the points of the two helices are coincident.
The tangent at one point of the curve is defined by its angle ẞ with the radius
sector on this point.
5
that for the same value of the angles ẞ will be equal in the two helices and conse-
quently the two tangents will coincide. It follows therefore that the gearing will be
perfect.
As will be seen this angle 3 varies with r, and consequently varies at every
point of the curve, decreasing in proportion as the tool advances towards the apex
of the cone.
In practice the knowledge that this angle corresponds with the centre of the teeth,
will give the angle of rotation to the tool about its axis, so as to avoid binding.
In reality the movement of the tool instead of being uniform is a uniformly varied
movement of a kind of sinusoidal movement, because the tool is actuated by a con-
necting rod and crank. This movement is preferably adopted instead of a uniform
rectilineal alternate movement so as to avoid shocks and backlash which are produced
in the latter movement when change in the direction of travel takes place, while the
movement by connecting rod and crank, being continuous avoids such shocks and
ensures a practically exact division, while at the same time the progressive variation
of speed secures a better engagement of the tool with the material.
It is only necessary to be careful to arrange, in setting, the conjugate pinions to be
cut according to the same marks with regard to the travel of the tool, so that any
slight difference in the sinsoidal curve will occur in the same manner in the two
pinions, and consequently there will be no inconvenience.
Thus, according to Figure 11 where the tool is represented as being at the
beginning of its advancing movement, if c represents its path of travel and the
length of the teeth it will be necessary to place the two conjugate pinions to be cut
at the same distances a and b, from the end of the travel of the tool.
Finally the helicoidal movement is produced automatically and requires no calcula-
tion. It is sufficient to employ the same movement for the two conjugate pinions
and to set both identically relatively to this movement.
It is this simultaneous employment of the two general principles described above,
by which the automatic shaping, division, and helicoidal cutting of the teeth is
obtained. Means are also provided for automatic uncoupling in one or the other
direction of movement.
In a framework A is mounted in suitable bearings, a driving shaft a provided with
two pulleys a¹ a² one of which is loose and the other fast, and which receive a rotary 4
movement from any system of transmission by means of a belt. On the shaft a is
keyed a stepped cone a³ which, by means of a belt transmits its movement to another
similarly stepped cone b¹ loosely mounted on a shaft b of the fixed poppet B; this
cone 6 is firmly connected with a toothed pinion 62 which gears with a pinion 63

page_text: 5
the same sleeve as a pinion 64, which gears with a wheel 65 keyed on the
shaft 6 in such a manner that by means of these intermediate gears the cone 6 wil
transmit to the shaft b a rotary movement of a speed which can be varied as required.
At its end, the shaft b carries a circular plate c provided with a diametrical groove
in which is adjustably arranged a crank pin c. For this purpose the pin is provided
with a screw-threaded eye, with which a screw c² engages.
a bevelled pinion gearing with a similar pinion ct fixed on an axle having a squared
On this screw is mounted
end so that it can be turned with a key so as to actuate the screw to move the pin c
nearer to or further from the centre of the plate c.
0 connecting rod c³ connected with a plate co, which can be transversely moved on a
On this pin c¹ is articulated a
guide . This guide c' is not fixed but is provided with a cylindrical hub which is
revolvably mounted in a support cs and provided with peripheral teeth gearing with
a toothed wheel d. This wheel d gears with another wheel d', the latter in its turn
gearing with another wheel d² keyed to one end of a shaft d³, while the other end of
5 this shaft is provided with a toothed pinion d which gears with a rack bar d
(Figures 1, 5 and 6) on a carrier do. This carrier serves as a guide for another
carrier d' provided with a nut ds in which engages a screw e mounted in a support el
carried on the lower extremity of the central shaft f of this part of the machine.
The screw e is provided at one of its ends with a pinion e2 gearing with a similar
pinion e³ mounted on the same axle as a conical pinion e¹; the latter gearing with a
bevel wheel e mounted with a similar wheel e on a sleeve e', which turns with slight
friction on the shaft f. The bevel wheel e gears with a pinion es, on the shaft of
which is provided with a toothed wheel e10 gearing with a similar toothed wheel ell
mounted on another shaft e¹2 (Figures 4 and 7), which, by means of intermediate
gearing e13 communicates its movement to a shaft et provided at one of its extremi-
ties with a pinion e¹, the latter gearing with a similar pinion e¹6 mounted on a shaft g
provided with a screw thread and squared at each end in order to receive a hand
crank or key for the purpose of turning it by hand.
The pinion 6 of the cone 6 gears with a wheel (Figure 5) rigidly connected to
the bevel pinion on a shaft 23. These two pinions, which gear with a third inter-
mediate bevel pinion is, have their hubs provided with clutches, so that either can be
coupled with a clutch sleeve keyed on the shaft 3, but capable of being longitudin-
ally displaced on said shaft. By means of a set of gear wheels i provided as in thread.
cutting machines with a horse-head arrangement, the shaft can transmit the
novement to another parallel shaft 7 provided with a pinion 3 gearing with a
wheel, with a double set of bevel teeth, which turns around the shaft f, having
uitable intermediate sleeves, as clearly shown in Figure 5. The wheel gears with
nother wheel 10 (Figure 6) mounted on a sleeve which surrounds the shaft e⁹,
ogether with a similar wheel i which, by transmission gearing 20 (similar to that
ctuated by the wheel e10) transmits the movement to a pinion 12 which gears with a
inion 13 (Figure 7) with a double set of teeth, the cylindrical set of teeth gearing
ith a wheel h¹. The pinion 13 is mounted on a sleeve surrounding the screw-
readed shaft
9.
The pinion his split in part of its length and can be clamped to its shaft h2 by
eans of a bolt 3. On the shaft h² is keyed a screw h arranged between the arms or
ds of a support, which can move together with it on the shaft h2, and is provided
th a nut 5 in which engages the screw-threaded shaft g.
The endless screw or worm gears with a wheel k (Figures 4 and 5) keyed in a
gitudinal groove of the hollow shaft of the movable head C in such a manner
to permit this shaft to be longitudinally displaced by sliding in the hub of the
eel k. At one of its ends the shaft is provided with a plate with circular
oves serving for the fixing of the work x to be cut.
ion to be cut rotates continuously at a uniform rate.
It therefore follows that the
ough the hollow shaft k so as to help in fixing of the work, as clearly represented
A central bar can pass
Figure 5. The support is so arranged as to turn at a certain angle on the
wg so as to allow the disengagement of the screw h from the wheel k.
n the shaft is mounted a toothed wheel gearing with another similar

page_text: wheel mounted on a shaft of the plate 12 (Figures 2 and 4) provided with a
diametrical groove in which can be adjusted by means of a screw, a crank pin 13. On
this pin is articulated a connecting rod which by suitable means can transmit
the movement to a pawl 15 which can be reversed from one side to the other so as to
be coupled in any direction required with a ratchet wheel mounted on the
shaft e
The movable head C with all its mechanism can turn, on a support C¹ around the
central shaft and be fixed in any required position by means of bolts or the like,
the heads of which engage with a correspondingly shaped groove provided in the
support C¹. The latter is provided with a toothed sector n with which engages an
endless screw or worm n¹ the shaft of which is connected by conical pinions n² with
a rod n³ squared at one end for the purpose of being turned by a hand crank or key.
The sector n is provided with a tooth for every degree, equal to 360 teeth for the
whole circumference, so that by making a complete turn of the shaft n³ the
movable head is displaced to the extent of one degree. Moreover on the shaft n³ is
provided a circular indicator 4 by means of which even fractions of a degree can be
very exactly set. Further the support C¹ has a scale divided into degrees and
fractions in combination with which an index pointed on the movable head works, as
represented in Figure 7.
The part C of the moveable head which can turn around the axle f carries a
screw engaging in a nut o' of the head C and squared at its end so as to be turned
by means of a hand crank o² for the purpose of either adjusting the movable head C
to or from the geometrical axis of the shaft f.
The plate c acts as a tool carrier and for this purpose it supports the tool by means
of a number of suitably combined carriers or parts.
The first p (Figure 7) of these carriers can be adjusted on the plate co by the
rotation of a screw ; the second p¹ has a movement perpendicular to the former by
turning of a screw 2. On this second carrier p¹ is rotatably arranged a third p²
which can be turned by rotating an endless screw 3 with which it engages and finally
a fourth, cylindrical, carrier p³ in which is fixed the tool y, is articulated on an axle 14.
This carrier is provided with a set of teeth gearing with an endless screw 4 by means
of which it can be made to turn round its axis.
On the axis of oscillation is loosely mounted a drum p³ (Figure 4) around which a
cord p is wound, the ends of which are secured to adjustable holders on supports
fixed on the slide c. The drum revolves the axle of oscillation of the tool on which
it is mounted actuated by spring friction in such a manner that it forms a kind of
spring box for the actuation of the said shaft.
The gear wheel of the slide c is itself in gear with a rack provided with a
groove in which, at a suitable distance apart, two stops ss (Figures 1, 2 and 3)
provided with inclined planes are fixed, adapted to strike against a roller t¹ (Figure 1)
provided at the end of a sliding rod t articulated to a three-armed lever t2. One of
these arms is provided with a finger 3 adapted to engage with one of two recesses
provided on a sector u, the opposite end of said lever being constantly pressed
upwards by a spring piston which forces the finger 3 to engage in either of the
two recesses of the sector u which may come under it. This sector u is rigidly
united with a lever u' which is articulated to a rod u² provided at one of its ends
with the belt shifting fork u³.

page_text: 20 greatest exactness, and it will now be explained how its position is regulated with
explained how the travel of the tool can be regulated with the
the same exactitude.
By moving the tool carriers p and p by turning the screws 1 and 2, the tool y is
brought exactly into the centre line Z-Z (Figure 7) which line is the line of inter-
section between a
5 perpendicularly to the axis of the fixed head, with another plane perpendicular to the
vertical plane passing through the axis of the shaft f.
preceding one, and passing through the axis of the cone of the pinion about to be
cut. By turning the circular carrier p³, by working screw 3, the necessary inclination
is given to the tool y, and by turning the sleeve p³ which carries the tool, by turning
the screw 4, the tool is made to turn round its axis so as finally to occupy the position
which most suitable for the purpose.
At the beginning of each reciprocating movement the drum involves by spring
friction the axle of oscillation of the tool in one direction or the other, and instan-
taneously places the tool in the position for work and return. The cord pe offers the
great advantage that it adapts itself easily to all the positions of the tool carrying
device c6 and of the tool itself, while its tension devices serve to regulate its engage-
ment on the drum p³.
RADIAL ADJUSTMENT OF THE PINION ABOUT TO BE CUT.
The pinion about to be cut being fixed by the shaft on the movable head or
on the plate mounted on this shaft, the pinion is placed in the required position,
o that the vertix of its cone should be in the geometrical axis of the shaft f. This
s done by suitably turning the screw o in one direction or the other according to
hether the movable head C is to be moved nearer to, or farther from, the shaft f.
his head C moves in dovetail grooves in the part 2 and can be fixed in the required
osition by tightening the bolts C³ C³.
THE CIRCULAR ADJUSTMENT OF THE PINION TO BE CUT.
It is necessary that the pinion should occupy such a position that one of the
neratrices of the cone corresponding to the depth of the teeth should be in the
aight line described by the tool y. In order to obtain this adjustment the pinion x
turned round the shaft f by turning the shaft n³ by means of a key placed on its
ared end, in consequence of which the gear-wheels n will also turn and one of
m will involve in its movement the worm n', which moves on the toothed sector n,

page_text: involving in its movement the movable support C2 as well as the head C with the
pinion, which is thus easily brought into the required position. By screwing down
the bolts m¹ m² the support C is firmly secured in place.
As the angle of the vertex of the cone of the teeth of the pinion to be cut is known,
this circular adjustment is easily obtained by bringing the zero index of the support C²
opposite to the number which denotes this angle on the degree scale division of the
fixed support C¹. From what has been described above it will easily be understood
that a turn of the handle of the shaft n³ will produce a displacement of the axis of
the movable head by one degree, and as the circular index n is divided into minutes
and fractions of minutes, the angular adjustment can be carried out with all the
precision desired.
THE MOVEMENT FOR AUTOMATICALLY DIVIDING THE TEETH AND MAKING THE
HELICOIDAL CUT.
The pinion 62 rotates the toothed wheel i and the conical pinion with which it
is solidly connected. The latter involves in its movement the pinions and i², and,
according to whether it is intended to cut the teeth with a right or left pitch the
sleeve is brought in connection with one or the other of the pawls of the
pinions and 2. The shaft 3 involves in its movement the set 6 of four gear wheels,
and consequently the shaft , the pinion 8 and the wheel . The latter com-
municates its rotatory movement to the pinions 110 and 11, to the transmission system
marked by the letters º º, to the pinions 12, and i¹³, and finally, to the pinion h¹.
If the nut of the screw bolt h³ of the latter is screwed down, the shaft h2 and the
screw will turn together, and the latter will involve in its movement the wheel k,
the shaft and the pinion x about to be cut. The latter is thereby given a rotary
movement, while the tool y is moved against it, describing, consequently, a helicoidal
curve.
The tool passes during its return movement over the tooth cut which it has just
made in such a manner as to operate on the next tooth during the following forward
movement; that is to say that if the pinion has 12 teeth for example each tooth
is subjected to the action of the tool at every twelfth reciprocating stroke of the
latter.
It will be easily understood now that by suitably choosing the number of teeth of
the set of the four wheels by a calculation analogous to that which is made for
the gearings for cutting screws, the tool y will cut on the wheel x the number of
teeth required. By slackening the screw belt 3 the shaft h² can be turned by hand
as well as the screw in such a manner that the wheel can be regulated according
to the thickness of the teeth. It is also possible to lower the support ht of the
screw / so as to uncouple the wheel k, a condition which allows the pinion * to be
turned by hand for the purpose of centreing it, or so to regulate the screw as to
compensate or re-adjust at will for wear and tear produced.
THE MOVEMENT FOR GIVING THE TEETH THE SHAPE OF THE INVOLUTE OF A CIRCLE.
It has been showed previously that the ratio between the angular speed of the
tool and the pinion to be cut, around their respective axes is represented by
Va of the tool
Va of the pinion sin ¦ a.
a being the semi-angle at the vertex of the primitive cone.
Annroximately so as to avoid any adiustment being carried out by the attendant

page_text: 5
Eue tool.
the pinion under work when the tool has passed over each tooth.
The rotary movement ought to be slow and only at each turn o
The wheel turns the wheel and the plate 12, the latter actuating the connecting
rod and the pawl 15. Inasmuch as the wheels and are equal, the pawl 15 wil
move the ratchet wheel 6 through a fraction of its revolution for every turn of the
wheels kand x. The ratchet wheel 16 involves in its rotary movement the pinions e15
and elo and the screw g. The nut h and, consequently, the support pass through
a translatory movement during which the screw h acts like a rack bar on the wheel
k, thereby turning the latter as well as the pinion a.
10 wheel involves in its movement the shaft e¹, gears e13, shaft 12, pinions ell and elo,
On the other hand the ratchet
shaft e, pinion e8, wheel e, sleeve e, wheel es, the pinions e, e³, e², and finally
the screw e.
The latter communicates a translatory movement to the carriers d',
de, and rack ³, the latter turning the carriers d', d², d', d and the slide c' which is
actuated by its toothed part c. The plate co, and consequently the tool y, participate
5 in the rotary movement of the guide c', the result of which is that the point of the
said tool is moved relatively to the pinion x, which turns like the tooth of a
wheel engaging with it, and this relative movement as regards the said pinion is
an involute of the circle according to which the teeth of the pinion x are cut.
By the combined movement of the carriers and 7, the mathematical relation
is obtained mentioned above, to understand which it is advisable to refer to the
schematic view, Figure 12.
It should be observed that the nut ( describes a path parallel to the nut h. The
two perpendicular carriers and d7 are moved along the sides of a rectangular
triangle, the hypotenuse of which is the straight line described by the nut ds.
Now, inasmuch as, owing to which adjustment of the pinion x, the screw e forms an
anglea with the transversal carrier, it follows that this carrier, provided with the
rack d', passes through the length of travel of the nut multiplied by sin. a.
is this amount which is transmitted to the wheel c by the intermediate action of the
wheels d and d², respectively proportional to the wheels k and c and also by
the intermediate wheels d and d¹.
It
There is thus established between the rotary movements of the tool y and the
pinion about to be cut, the required proportion of the angular speeds equal to
sin. a.
The direction of movement of the screws g and e is such that their rotation is
effected in a suitable direction.
The handle placed on one of the ends of the screw shaft g allows this rolling
novement to be brought about by hand, which is thus added without interfering with
t, to the movement for effecting the helicoidal division, forming the object of the
ormer paragraph.
THE MOVEMENT FOR AUTOMATICALLY UNCOUPLING.
The automatic uncoupling is regulated by the position and the distance between
he inclined plane stops, ss on the rack bar r.
heel co, a rectilinear ascending and descending motion according to whether it is
The latter receives, from the
tended to cut the pinion x, or its conjugate pinion, or, according to the direction
movement given to the rack bar. At a certain moment one of the stops 8 meets
e roller t and moves it and with it the rod t.
cillate, whereupon the finger t³ leaves the recess in the sector u, in which it was
The latter causes the lever 2 to
gaged, and the lever u¹, under the action of a spring (not shown) enclosed in a
sing, is energetically drawn to the right, Figs. 1 and 5, in such a manner that the
aft u² and the fork u³ are moved in the same direction owing to which the belt
shifted from the fast to the loose pulley a¹, thereby stopping the machine
omatically as soon as the tool y has finished its work.
V₁ becomes
At this moment the finger ts, under the action of the small spring piston
aged in the other recess of the sector u in order to ensure the position of the belt
the loose pulley.

page_text: In order to again start the machine it is necessary to disconnect the finger t³ from
the said recess by raising by hand the lever t2 and causing the lever u¹ to oscillate
until the finger engages in the other recess, a position which corresponds with the
position of the belt on the fixed pulley a².
OILING OF THE TOOL AND THE RECOVERY OF THE LUBRICANT.
A small centrifugal pump F actuated by the principal operating shaft a draws up
oil from a reservoir F¹ to force it out on the tool through a suitable conduit, the
superfluous oil being collected by gutters arranged for that purpose on the framework,
which deliver it back to the reservoir F¹ from which it is drawn up again by the
pump for further use in connection with the tool y.
THE CUTTING OF THE CONJUGATE PINION.
In order to cut the pinion which is intended to gear with the pinion x, the former
is placed on the shaft under the same conditions as the latter. The course of the
tool y is not altered but the tool-carrying device is so arranged that the course
described by this tool has its extremities at the same distances a and b (Figure 11)
from the corresponding ends of the teeth as in the former case. Moreover, if the
two conjugate pinions to be cut are not intended to be provided with the same number
of teeth it will be necessary to exchange the set of gear wheels 2 so as to produce
the number of teeth required for the second pinion, and their travel is reversed by
the adjustment of the sleeve in such a manner that the helix of the teeth of one
pinion are provided with a pitch to the right, and those of the second with a pitch
to the left.
The conjugate pinions cut in this manner will perfectly gear with each other, as
has been demonstrated above.
Finally, means and devices are provided for facilitating the adjustment of the
wheels to be cut; but these are independent of the machine which is the object of
this invention, and are capable besides of being varied according to the require-
ments of the users of these machines.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, declare that what I
claim is
1. A machine for automatically cutting conical helicoidal teeth in which the
movement of the reciprocating cutting tool is so combined with that of the rotating
work that the cut generated in the work is helicoidal.
2. In a machine for automatically cutting conical helicoidal teeth the combina-
tion with a fixed head and a head movable round a vertical axis passing through the
vertex of the cone of the wheel to be cut, of a guide concentrically mounted round
the shaft of the fixed head, a plate movable in the slide and connected to a rod the
pin of which is adjustably mounted in a plate rigidly connected with the shaft of
the movable head a tool-carrier, means for preventing jambing of said tool, means
for dividing the wheel to be cut and for moving it in such a manner that the tool
will cut the helicoidal teeth in the shape of the involute of a circle, substantially as
described.
3. In a machine for automatically cutting conical helicoidal teeth the combination
with a fixed head and a movable head of a guide rotatably arranged round the shaft
of the fixed head, a plate movably mounted in said guide, a carrier po perpendicularly
movable on the guide, a second carrier perpendicularly movable on the latter, a third
circular carrier gearing with an endless screw or worm, and rotatably arranged on the
first carrier p¹, a fourth carrier articulated on the third carrier, in the interior of which
is arranged a cylinder rotated by endless screw carrying the tool, the hinged pin of
the circular carrier being provided with the drum on which is wound a cord, the ends
of which are attached to two fixed points on the guide, substantially as described.
4. In a machine for automatically cutting conical helicoidal teeth, the combination

page_text: with a fixed head and a head movable circularly, of a rotatory shaft mounted on the
movable head and carrying at its end the pinion to be cut, means for communicating
a rotatory movement to this shaft, connections between this shaft and a crank plate
as 12, a rod connected thereto, the pin of which can be adjusted in a diametrically
arranged groove in the said plate, a pawl connected with the rod and connections
between a ratchet wheel with which the pawl engages and a guide as c', of the tool-
carrying plate to cause the tool to generate the involute curve of the teeth to be cut
substantially as described.
5. In a machine for cutting conical helicoidal teeth the combination with a fixed
head and a circularly movable head, of a rotatory shaft, as b, mounted on the fixed head,
a pinion on said shaft, a speed-changing device with conical gearing and sleeves with
clutches connected with the pinion, driving gearings as 6, the number of teeth of the
wheel of which may vary according to the number of teeth of the pinion to be cut,
a shaft actuated by the driving gearing, and means for connecting the shaft and the
rotatory shaft mounted on the movable head and carrying the pinion to be cut sub-
stantially as described.
6. In a machine for cutting conical helicoidal teeth the combination with a
movable head of an endless screw, as n¹, gearing with a graduated and toothed sector
on the frame, a support carrying the movable head resting on the frame and capable
of turning around a pivot, as f, of the machine, the geometrical axis of which passes
through the vertex of the cone of the pinion to be cut substantially as described.
7. In a machine for cutting conical helicoidal teeth a transmission device for the
shaft carrying the pinion to be cut and a revoluble guide as c, provided with the
tool-holding plate, characterised by mechanism consisting of a series of gear wheels
connecting the shaft and the pivot, as f, of the machine, the latter being connected
by gearing with the screw of a carrier, as ", movably mounted on a rack bar connected
by gearing with the toothed portions of the revoluble guide, substantially as
described.
8. In a machine of the kind described, means for imparting a reciprocating motion
to the cutting tool substantially as described or illustrated in the accompanying
drawings.
9. In a machine of the kind described means for imparting a rotatory motion to the
work substantially as described or illustrated in the accompanying drawings.
10. A machine for cutting conical helicoidal teeth substantially as described or
llustrated in the accompanying drawings.
Dated this 24th day of November 1900.
BOULT, WADE & KILBURN,
Agents for the Applicant.