Improvements in Arrangements and Mechanism for Cutting or Producing the Teeth of Mitre and Bevel Wheels.
Year: 1899

page_text: Date of Application, 20th July, 1899
Complete Specification Left, 5th Apr., 1900 -Accepted, 20th July, 1900
Improvements in Arrangements and Mechanism for Cutting or
Producing the Teeth of Mitre and Bevel Wheels.
We, SMITH AND COVENTRY, LIMITED, of Gresley Iron Works, Salford,.
Manchester, in the County of Lancaster, Engineers and Tool Makers, and
THEODORE COVENTRY, Managing Director of the said Company, do hereby declare
the nature of the said invention, to be as follows:-
1. Our invention relates to a method or system to be applied to machines for
cutting the teeth of mitre and bevel wheels in such manner that the shape or
curves given to such teeth will be the same as those obtained when drawing
curves of teeth of spur wheels produced by the method and instrument known as
the "odontograph," and this without the use of shapers commonly used in such
wheel cutting engines.
The shapes or curves produced by this invention are those resulting from two
movements, one by the cutter or cutters changing in position to give the thick-
ness of the teeth at various points of their depth, and the movement of the blank
wheel which is being cut towards the cutters, these two movements by this inven-
tion are combined and connected, and the result of the two is the curve or shape
required to be given to the mitre or bevel wheel teeth without shapers, which
are expensive to make and a great number are required to suit all wheels to
be cut in the machine.
The cutters, when two are used, are each mounted on an arm or lever having
the same fulcrum (hereinafter termed the former arm) so as to have a planing
movement given to them to cut the teeth, and these former arms are moved to
and from each other in a curve produced by one or two radial arms (or a double
radial arm, one on each side of its axis) which are in length, measured from
centres, one fourth of the length of the former arm or arms from their fulcrum,
these radial arm or arms being adjusted at an inclination or angle to a plane
passing horizontally through the axis or fulcrum of the former arms and the
radial arms of 75 degrees when the radial arm or arms are in that position which
corresponds with the pitch line position of the wheel to be cut as by the odonto-
graph system. Thus the curve described by the radial arm or arms is that
produced by compasses with one fourth the radius of the wheel from a point in
a line from the axis of the radial arm at the angle of 75 degrees above referred
to.
In order that the curve thus obtained from the radial arm or arms may give
accurate movement to the former arms according to our invention, the radial arm
or arms are made to give parallel movement to one or two bars, which bar or bars
are connected with the former arms, so that the movement thus obtained and'
given to the parallel bars, is imparted to the former arm or arms by connection
therewith, and will give positions to the cutters carried by them, that will produce
the desired curve or form of teeth required in mitre or bevel wheels when such

page_text: movements thus imparted to the former arms are combined with that imparted
to feed the blank wheel towards the cutters.
This arrangement produces the correct curve or shape of tooth required for
mitre wheels or wheels of an angle of 45° for all sizes intended to be cut in
the machine.
But it will not be correct for wheels of greater or less angle than 45°, and
our invention also consists in altering the angle 75° for the pitch line position
of the radial arm or arms for mitre wheels to suit other angles of wheels, and
this is done by calculation, and by means of an index on one (if two are used)
of the parallel bars or in any other convenient position, which index will give
the correct position, inclination or angle of the radial arm or arms at the pitch
line position suitable to the angle of the wheel to be cut.
But besides altering the inclination or angle of the radial arm or arms to
suit the angle of the wheel to be cut above referred to, the length of the curve
described by the radial arm or arms has to be altered by our invention, and this
is ascertained by calculation so that the correct ratio between the movement to
feed the blank wheel towards the cutters and the movement imparted to the
radial arm or arms has to be adjusted according to the angle of the wheel to be
cut, the proper ratio being shown by an index on levers which connect the
radial arm and the mechanism feeding the blank to the cutters.
2. Our invention may be carried out by various arrangements and combinations
of mechanism, and we do not confine ourselves to any special combination so long
as such mechanism acts substantially upon the principle herein before explained
under the first head of our invention, but in orer that our invention may be
more clearly understood, we describe one arrangement and combination which we
so far consider the simplest and best and in doing so will show how it is or may
be combined with that engine for cutting mitre and bevel wheels described in
the Complete Specification of Letters Patent granted to John Buck numbered 8418
of 1895, and this part of our invention also consists in the combination of our
improvements with the machine described in the said Complete Specification. In
that machine hereinafter referred to as Buck's machine, there are two levera
or former arms on the same fulcrum each carrying cutters, one former arm for
cutting or shaping the upper side of the tooth, the other for the lower side of the
same tooth at the same time, the lengthway of the tooth being cut being horizontal
when being cut and coming between the two cutters. The opening and closing of
the former arms in the said Buck's machine to give the thickness and shape of the
tooth is effected by studs in slots in the ends of the former arms, which studs
enter slots one for each, arm in a disc partly rotating with a shaft, and it is these
slots which are shapers and give the curve desired, and many of them are
required to suit all wheels than can be cut in the machine, and they are expensive
to make.
In about the position of the shaft for the shaper disc in the Buck machine, we
place a shaft and secure on one end of it, a straight lever having two radial
arms, one arm on the opposite side of the axis of the shaft to the other.
The length of these radial arms in relation to the former arms is as herein-
before explained, and the end of each radial arm is jointed to a straight bar-
and one end of a link of exactly the same length as the radial arms is jointed
to the framing or to a bracket from the framing at some distance on one side
of the shaft actuating the radial arms, and the other ends of these links (one for
each radial arm and parallel bar) are respectively jointed to the said straight bars.
This arrangement constitutes a parallel motion keeping the two straight bars
parallel to each other in all their movements produced by the radial arms.
Each parallel bar has a straight groove in its lengthway in which a block fits
and can slide freely therein, and in each slide block there is a hole for a pin
which is in a plate or part which can be secured to the end of one former arm at
which end there is a slot radial to the axis or fulcrum of the former arms, and
this radial slot permits the position of each arm to be adjusted to the thickness

page_text: of the tooth desired to be cut. It will thus be seen that the radial arms each
impart an up and down movement to their respective parallel bars in accordance
with the curve described by the free ends of the radial arms.
The shaft upon which the radial arms are secured is oscillated by connection
with the mechanism giving movement to the carriage having the headstock for
the shaft carrying the blank of the wheel to be cut (which is arranged as in the
said Buck's machine) and this carriage can be connected or dis-connected as
required, and as the movement is transmitted through levers, the ratio between
the movement of the carriage and the radial arms can be adjusted as required.
The position of the radial arms for the pitch line of the wheel to be cut is
fixed by an index on one of the parallel bars to which index a mark on the
sliding block may be brought and the ratio of movement between the radial arms
and carriage is also fixed by an index on one of the transmitting levers to which
a stud is adjusted for the angle of the wheel to be cut.
Our improvements are applicable to other bevel wheel cutting engines besides
Buck's, and can be arranged if desired to finish the cutting of one tooth before
changing to the next tooth.
PETER J. LIVSEY,
Agent.
Improvements in Arrangements and Mechanism for Cutting or
Producing the Teeth of Mitre and Bevel Wheels.
:-
We, SMITH AND COVENTRY, LIMITED, of Gresley Iron Works, Salford,
Manchester, in the County of Lancaster, Engineers and Tool Makers, and
THEODORE COVENTRY, Managing Director of the said Company, 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:-
1. Our invention relates to a method or system to be applied to machines for
cutting the teeth of mitre and bevel wheels in such manner that the shape or
curves given to such teeth will be the same as those obtained when drawing
curves of teeth of spur wheels produced by the method and instrument known
as the odontograph," and this without the use of shapers commonly used in
such wheel cutting engines.
The involute shapes or curves produced by this invention are those resulting
from two movements, one by the cutter or cutters changing in position to give
the thickness of the teeth at various points of their depth, and the movement of
the blank wheel which is being cut towards the cutters, these two movements by
this invention are combined and connected, and the result of the two is the
involute curve or shape required to be given to the mitre or bevel wheel teethi
without shapers, which are expensive to make and a great number are required
to suit all wheels to be cut in the machine.
The cutters, when two are used, are each mounted on an arm or lever having
the same fulcrum (hereinafter termed the former arm) so as to have planing
movement given to them to cut the teeth, and these former arms are moved to
and from each other in a curve produced by one or two radial arms (or a double
radial arm, one on each side of its axis) which are in length, measured from
cenires, one fourth of the length of the former arm or arms from their fulcruni,
these radial arm or arms being adjusted at an inclination or angle to a plane
passing horizontally through the axis or fulcrum of the former arms and the radial

page_text: arms of 75 degrees when the radial arm or arms are in that position which
corresponds with the pitch line position of the wheel to be cut, as by the odonto-
graph system when producing curves approximate to the involute. Thus the
curve described by the radial arm or arms is that produced by compasses with one
fourth the radius of the wheel from a point in a line from the axis of the radial
arm at the angle of 75 degrees above referred to.
In order that the curve thus obtained from the radial arm or arms may give
accurate movement to the former arms according to our invention, the radial
arm or arms are made to give parallel movement to one or two bars, which bar
or bars are connected with the former armis, so that the movement thus obtained
and given to the parallel bars, is imparted to the former arm or arms by con-
nection therewith, and will give positions to the cutters carried by them, that will
produce the desired curve or form of teeth required in mitre or bevel wheels
when such movements thus imparted to the former arms are combind with that
imparted to feed the blank wheel towards the cutters.
This arrangement produces the correct curve or shape of tooth required for
mitre wheels or wheels of an angle of 45° for all sizes intended to be cut in the
machine.
But it will not be correct for wheels of greater or less angle than 45°, and
our invention also consists in altering the angle 7510 for the pitch line position
of the radial arm or arms for mitre wheels to suit other angles of wheels, and this
is done by calculation, and by means of an index on one (if two are used) of the
parallel bars or in any other convenient position, which index will give the
correct position, inclination or angle of the radial arm or arms at the pitch line
position suitable to the angle of the wheel to be cut.
But besides altering the inclination or angle of the radial arm or arms to suit
the angle of the wheel to be cut above referred to, the length of the curve
described by the radial arm or arms has to be altered by our invention, and this
is ascertained by calculation so that the correct ratio between the movement to
feed the blank wheel towards the cutters and the movement imparted to the
radial arm or arms has to be adjusted according to the angle of the wheel to
be cut, the proper ratio being shown by an index on levers which connect the
radial arm and the mechanism feeding the blank to the cutters.
2. Our invention may be carried out by various arrangements and combinations
of mechanism, and we do not confine ourselves to any special combination so long
as such mechanism acts substantially upon the principle herein before explained
under the first head of our invention, but in order that our invention may be
more clearly understood, we describe one arrangement and combination which
we so far consider the simplest and best and in doing so will show how it is or
may be combined with that engine for cutting mitre and bevel wheels described
in the Complete Specification of Letters Patent granted to John Buck num-
bered 8418 of 1895, and this part of our invention also consists in the combination
of our improvements with the machine described in the said Complete Specifica-
tion. In that machine hereinafter referred to as Buck's machine, there are two
levers or former arms on the same fulcrum each carrying cutters, one former arm
for cutting or shaning the upper side of the tooth, the other for the lower side
of the same tooth at the same time, the lengthway of the tooth being cut, being
then horizontal and coming between the two cutters. The opening and closing
of the former arms in the said 'Buck's machine to give the thickness and shape
of the tooth is effected by studs in slots in the ends of the former arms, which
studs enter slots one for each arm in a disc partly rotating with a shaft and it is
these slots which are shapers and give the curve desired, and many of them are
required to suit all wheels that can be cut in the machine, and they are expensive
to make.
In about the position of the shaft for the shaper disc in the Buck machine,
we place a shaft and secure on one end of it, a straight lever having two radial
arms, one arm on the opposite side of the axle of the shaft to the other.

page_text: The length of these radial arms in relation to the former arms is as herein-
before explained, and the end of each radial arm is jointed to a straight bar, and
one end of a link of exactly the same length as the radial arm is jointed to the
framing or to a bracket from the framing at some distance on one side of the
shaft actuating the radial arms, and the other ends of these links (one for each
radial arm and parallel bar) are respectively jointed to the said straight bars.
This arrangement constitutes a parallel notion keeping the two straight bars
parallel to each other in all their movements produced by the radial arms.
Each parallel bar has a straight groove in its lengthway in which a block fits
and can slide freely therein, and in each slide block there is a hole for a pin
which is in a plate or part which can be secured to the end of one former arm
at which end there is a slot radial to the axis or fulcrum of the former arms, and
this radial slot permits the position of each arm to be adjusted to the thickness
of the tooth desired to be cut. It will thus be seen that the radial arms each
impart an up and down movement to their respective parallel bars in accordance
with the curve described by the free ends of the radial arms.
The shaft upon which the radial arms are secured is oscillated by connection
with the mechanism giving movement to the carriage having the headstock for
the shaft carrying the blank of the wheel to be cut (which is arranged as in the
said Buck's machine) and this carriage can be connected or disconnected as
required, and as the movement is transmitted through levers, the ratio between
the movement of the carriage and the radial arms can be adjusted as required.
The position of the radial arms for the pitch line of the wheel to be cut is
fixed by a scale on one of the parallel bars to which scale a fixed index from
the frame may be brought and the ratio of movement between the radial arms
and carriage is also fixed by a scale on one of the transmitting levers to which a
stud is adjusted for the angle of the wheel to be cut.
Our improvements are applicable to other bevel wheel cutting engines besides
Buck's, and can be arranged if desired to finish the cutting of one tooth before
changing to the next tooth.
"
Fig. 1, is an elevation looking in front of the "former arms upon which the
cutting tool holders are carried, the mechanism for holding the wheel to be cut
being removed.
Fig. 2, is a plan view,--parts of the mechanism being omitted.
Fig. 3, is a front elevation on a larger scale and detached, of an indexed arm
or lever with formula for calculating the scale hereinafter referred to.
Fig. 4, is an elevation at a right angle to that shown by Fig. 1, in which
some parts are shown in section.
Fig. 5, is a plan view similar to Fig. 2, but in this figure some parts are in
section and other parts omitted from Fig. 2, are shown.
Fig. 6, is a front elevation in the plane of Fig. 1, of the framing with some
parts shown in section.
Fig. 7, is an elevation partly in section, which is taken in the line of the axis
of the stepped pulleys for driving the machine.
Fig. 8, is a detached elevation on an enlarged scale across the former arms
partly in section looking from their fulcrum showing the radial arms or levers,
the parallel bars and connected mechanism.
Fig. 9, is a front elevation of the free ends of the former arms and the con-
nected mechanism on the same scale as Fig. 8.
Fig. 10, is an elevation partly in section of the headstock and connected
mechanism for the shaft and mandrel carrying the wheel to be cut, and mechanism
for actuating the carriage for the headstock. and automatic mechanism for
stopping the feed to the cutters, the section being in the line of the axis of
the shaft or mandrel for the wheel to be cut.
Fig. 11, is an elevation looking towards the outer end of the mandrel for
the wheel to be cut, showing the dividing wheel the mechanism for actuating it.
and part of the feed and automatic stop mechanism.

page_text: Fig. 12, is a detached side elevation of the excentric fixed on the shaft or
mandrel of the wheel to be cut for giving the feed at each revolution of the
dividing wheel.
Fig. 13, is a diagram with formula connected with it for calculating one of
the scales on the upper parallel bar.
Fig. 14, is a front elevation of one of the cutting tool holders or boxes, but
the cutter and connected mechanism is omitted.
Fig. 15, is a plan or top view (one of which is shown in position in Fig. 5)
showing the cutter and mechanism for locking it.
Fig. 16, is an end elevation looking from the right of Figs. 14 and 15, part
being in section on the line A-B Fig. 15, the outside end elevation of both tool
holders being shown in position on Fig. 4.
Fig. 17, is an elevation in section on the line C-D looking from the left of
Figs. 14 and 15.
Fig. 18, is a plan section, showing the cutter screw for adjusting it and wedge
bolt for locking it in the box in the line E-F Fig. 14.
Our improvements are illustrated combined with those described in the
Specification of Buck's British Patent hereinbefore referred to, but as modifica-
tions in and additions to what may be termed Buck's invention are made, it will
be necessary to refer to all the parts of our complete machine in order that our
improvements may be fully comprehended.
1, is the frame of the machine-2, Fig. 7, is a tubular stud, the interior bore
being for lubricant.
On this stud there is a tube or sleeve 3, kept from moving endways by a
collar 4, on the end of the stud and upon this sleeve the stepped driving
pulleys 5, are keyed. The sleeve at its inner end has a spur pinion 6, which
gears with a wheel 7, keyed on the back end of a shaft 8, in bearings in the
framing, (see also Figs. 5 and 6).
This shaft has a disc 9, solid with its front end, across which there is an
undercut slot in which an adjustable stud 10, can be secured at any required
distance from the axis of the shaft 8, (see also Fig. 5) and to this adjustable
stud, one end of a connecting rod 11, is jointed, the other end being jointed to a
stud 12, secured in a slide 13, which can thus be moved to and fro on a slide-
way 14, on the framing, shown in Figs. 5 and 6.
To the slide 13, two studs or pins 15, are secured, each for one end of a con-
necting rod 16, to be jointed to it, the other ends of which rods are jointed one
to each stud 17, on a slide 18, having slideways 19, formed one on each former
arm 20.
It is upon the slides 18, that the tool box is mounted for the cutting tool, one
cutter being to operate on the upper side of the tooth and the other on the
lower side, the lengthway of the tooth from its root being horizontal when being
cut.
When the former arms 20 are nearest together, the two cutters can be adjusted
to cut in the same straight line, that is in a sense on opposite sides of the same
line, if a line can be understood to have sides, but they are separated to give the
required thickness to the teeth to be cut and thus cut on opposite sides of it.
The construction and arrangement of the cutting tools and holders will be herein-
after described.
The wheel for dividing the wheel to be cut is or may be moved after each cut,
and it is moved in the machine illustrated after each cut, and this movement is
given by a cam disc 21, secured to the dise of the spur wheel 7, by screws, and
the cam groove 22 is shaped (see Fig. 6) to give a back and forward movement
while the cutters are making their back or non-cutting stroke.
A bowl on the end of a lever 23 works in the cam groove and this lever has
its fulcrum on a stud 24, in the framing, and the lower end of this lever is
slotted for an adjustable stud 25, which forms the joint pin for one end of a rod 26,
the other end of which is jointed to the end of an arm 27 on a shaft 28 in

page_text: bearings on the framing, which shaft has another arm 29 having a stud in its
end for a bowl that fits a groove in a part 30 (see Fig. 4), which can slide up and
down a tubular stud 31 in the vertical axis upon which the carriage 32 can
oscillate, hereinafter referred to.
There is another arm 33 see Fig. 2, having a stud carrying a bowl which also
fits in the groove in the sliding part 30 and this arm is secured on a shaft 34
having its bearings in the carriage 32 (see Figs. 2, 10 and 11) so that movements
are transmitted from the cam 22 in whatever position the carriage 32 may be
but the mode of transmitting the movements from the shaft 34 to the dividing
wheel will be hereinafter explained.
On the upper face of the bed of the framing, a plate 35 (see Fig. 4) is secured
by set screws (one of which 36 is shown in Fig. 4). This plate 35 has a boss 37
that fits a hole for it in the framing.
It also has an undercut slot 38 in a curve from the axis 31 for the purpose
hereinafter mentioned, and it also has teeth 39 on its edge to fit a worm-herein-
after referred to. The carriage 32 is above the plate 35 and oscillates with a
bush 40 in the hole in the plate 35, which bush is secured by the tubular axis 31
in the centre of the bush 40 by a washer and screw nut 41 at its upper end.
The carriage 32 is thus held down at that point and by a projection 42 from its
front edge hooking under the outer edge of the plate 35. In this projection 42
bearings are formed for a shaft 43 which is arranged so that it cannot move
endways in the projection, and upon this shaft 43 the worm 44 is keyed, that
works in the teeth 39 in the edge of the plate 35.
The outer end of the shaft 43 has a bevel wheel 45 secured to it (see Fig. 2)
which gears with one 46 on the end of another shaft 47 in bearings from the
carriage, the outer end of which has squares upon it for a key to rotate the shaft,
so that the carriage can thus be moved to and fro and adjusted as required.
It is through this mechanism that the feed is given towards the cutters as
hereinafter explained.
The carriage 32 at its outer end has a fixed headstock 48 (see Figs. 4 and 10)
secured to it and it has also slideways 49 for an adjustable headstock 50.
There is a screwed spindle 51 in bearings in the carriage, which spindle is arranged
so that it cannot move endways, and the screw spindle, screws through a nut 52
secured in a recess in the end of the moveable headstock, which can thus be
adjusted (and thus the wheel to be cut on its mandrel) by rotating the spindle 51
by a key fitting the squares on its outer end.
The adjustable headstock 50 (see Fig. 10) has a bearing coned at one end for a
tubular spindle or shaft 53 and this shaft is made to move endways with the
movable headstock without play, by a washer and screws 54 upon it, which when
tightened draw the cone end of the spindle within the bearing for it. Within
the tubular spindle 53 the cone end of the mandrel 55 fits.
Its inner end has a screw tapped hole into which the screw on the end of the
long set screw 56 within the tubular spindle 53 screws, and this draws the man-
drel tightly within the spindle so that there is no end play and the mandrel and
shaft when adjusted are held firmly and rotate together.
It is upon the inner end of this mandrel that the wheel (not shown) to have
teeth cut in it is secured by a screw nut 57 (see Fig. 5).
The small end of the mandrel projects over the vertical axis 31 and enters a
bearing in a stand 58 (shown in Fig. 6) which stand can be adjusted to and fro
in the lengthway of the mandrel, and when adjusted, secured by a bolt, the end
of which enters the undercut slot 59 in the carriage shown in Figs. 2, 5 and 6.
This stand 58 is to resist any lateral strain put upon the mandrel when the teeth
are being cut.
The spindle 53 fits and can slide freely through a tube or sleeve 60 having its
bearing in the fixed headstock 48, and this sleeve is prevented from moving end-
ways by a collar 61 at one end, and the excentric 62 secured at the other end for
giving the feed to the cutters.

page_text: The spindle 53 and sleeve are made to rotate together by a sliding key 140
and keyway in the spindle (see Fig. 10). Upon the outer end of this sleeve 60
the dividing wheel 63 is secured by a key, and is further secured by a divided
screw nut having an arm 64 from one half of it by which it can be rotated, that
screws onto the outer end of the sleeve 60 and against the boss of the dividing
wheel. This nut is made in two halves which can be drawn together by set
screws so that when screwed firmly, the screws are tightened to prevent
unscrewing.
The dividing wheel 63 may have as many teeth in it as there are teeth in the
wheel to be cut, but the same dividing wheel may have more teeth-for example
a dividing wheel of 120 teeth will do for cutting wheels of 120, 60, 40, 30, 24, 20
and so on, the dividing wheel being moved one or more teeth according to the
number of teeth in ilfe wheel to be cut.
The dividing wheel is moved after each cut by a pawl 65 (see Fig. 11) jointed
on a pin in a block 66 which can slide in a slot in an arm 67 that is arranged
to oscillate round the boss on the fixed headstock 48. The slide block 66 is pushed
inwards by an helical spring 68 one end of which abuts against the sliding block,
the spring coming upon a pin on the block to keep it in position. The spring 68
forces the pawl into gear.
The arm 67 for the propelling pawl 65 extends across to the opposite side of
its fulcrum, and has a cam edge 69 formed upon it, which comes in contact with
a bowl 70 on a stud at one side of a retaining pawl 71 jointed on a stud 72
secured in the headstock 48. This retaining pawl has a tail part 73 to which
one end of an helical spring 74 is secured, the other end being connected with
an adjusting screw 75 passing through an eye from the carriage so that the tension
of the spring upon the pawl may be regulated.
When the arm 67 is moved backwards to take a fresh tooth of the dividing
wheel 63, the cam incline 69 pushes the retaining pawl 71 clear of the teeth in the
dividing wheel and holds it clear until the pawl 65 has completed its propelling
stroke when the retaining pawl is allowed to enter the teeth of the dividing wheel
and hold it from rotating while the cut is being made. The propelling pawl also
stands at the extreme of its propelling stroke by the cam actuating it, which
dwells or gives no movement during the cutting stroke.
The oscillating movement is given as hereinbefore described from the shaft 34
by an arm 76 to which one end of a connecting rod 77 is jointed, the other end
being jointed to a part secured or formed upon the arm 67 (see Fig. 11).
The propelling pawl makes one uniform length of stroke, and if its stroke is
equal to say six or more teeth of the dividing wheel, and the dividing wheel is
required to move to the extent only of one of its teeth, then the pawl is only
allowed to enter the teeth of the dividing wheel when it has arrived at the end
of its stroke within about the space of one tooth and so on when two or more
teeth are to be taken.
This is effected by a plate 78 that can be adjusted round the collar 61 on the
sleeve 60, which plate has an edge 79 over which the propelling pawl 65 rides,
keeping it out of the teeth of the dividing wheel, and only allowing it to fall
into them at the proper time.
This disc plate 78 can be adjusted by means of a concentric slot 80 in it for
a bolt 81, the shank of which bolt passes through a hole in a bracket 82 secured
to the top of the fixed headstock and by a winged screw nut 83, this bolt can be
tightened to draw the head of the bolt against the plate and hold it firmly
against the bracket (see Figs. 10 and 11). The feed to the cutters at each rota-
tion of the dividing wheel is given by the excentric 62 acting through its rod 84
which is jointed to an arm 85 secured on a shaft 86 having its bearings in the
carriage.
At the front end of this shaft 86 there is a spur toothed wheel 87 loose on the
shaft, which wheel gears with one 88 also loose on the outer end of the shaft 47,
the boss of which has clutch teeth which can gear with clutch teeth on a grooved

page_text: boss 89 that can slide on a key on the shaft 47 so that when the clutch is in
gear, the wheel drives this shaft.
The slide clutch is moved by a fork 90 forming one arm of a bell crank lever
(see Figs. 10 and 11) which lever is on a stud 91 secured in the framing.
The wheel 87 comes between two arms 92 secured on the shaft 86 (or there may
be one arm 92 only) and a pawl 93 is jointed on a pin between the two arms.
This pawl is arranged to take one or more teeth of the wheel 87 according
to the extent of feed desired by an arrangement of disc plate 94 similar to that
for the propelling pawl 65 for the dividing wheel the disc plate being close to
the wheel and loose on the shaft, being adjusted by means of a concentric slot 95
in it. and a screw bolt 96 and winged nut, the bolt passing, through a hole in a
bracket 97 secured to the carriage (see Fig. 11).
The horizontal arm 98 of the bell crank lever passes between a notch in a
projection 99 from the carriage, to keep it from moving laterally.
It is pulled down by an helical spring 100 secured to it at one end and to a
stud 101 from the carriage at the other end, so that the spring when allowed
will throw the feeding clutch out of gear.
In the end of the horizontal arm 98 of the bell crank lever, a square headed
hard steel pin 102 is secured by a set screw 103 long enough to form a handle
to lift the long arm 98 of the bell crank lever when required.
When lifted the pin 102 rests on the upper side of a rod 104 square at its
end having a notch in it through which the pin 102 can pass when the rod has
moved sufficiently endways. This rod 104 slides through a hole in the carriage,
and at the opposite end has a head upon which one end of an helical spring can
act, the spring (not shown) being round the rod and abutting against a shoulder
in the hole for the rod.
There is a bracket 105 (see Fig. 5) secured to the table by a bolt, the head of
which enters the undercut slot 38.
It is by fixing this bracket at such a position that the end of the rod 104 will
come against it, and it will cause the rod to slide, and when slided by the last
feeding movement to be given, the notch at the other square end of the rod allows
the pin 102 to pass through and the spring 100 acts to put the feed mechanism
out of gear.
This is the automatic stopping of the movement of the carriage towards the
cutters when they have cut to the depth required, and if the machine works on
afterwards, there is no cutting after the dividing wheel has made one complete
revolution after the last feeding movement.
The description so far of the drawings has been of the Buck machine, but as
modified and with additions according to our invention.
The principal feature of our invention will next be described, by which it can
be made to give the correct shape to the teeth of the wheels to be cut without
the use of special shapers hitherto used.
The two former arms 20 both have their fulcrums 100 on the same stud secured in
the framing shown best in Fig. 5.
The back of the former arms come close against a vertical facing formed on
the framing, and they are held against this face so as to prevent any tendency
to twist by projections 107 (see Figs. 1 and 4) from their upper edges, that enter
into a recess formed by a projection and plate 108 secured to the framing, this
permits the former arms to be freely moved to and from each other to the extent
desired.
This tendency to twist is or may be further provided against by bolts 109 passing
through slots 110 in the framing (see Fig. 6) the heads of which bolts enter a
recess for each in the face and pass through holes in the former arms (see also
Fig. 4). The free ends of the former arms are shown best on an enlarged
scale by Figs. 8 and 9.
They have each a slot 111 in a radius struck from the axis of their fulcrum 106
and in each slot there are two screws or bolts 112 which pass into a part 113

page_text: having a pin 114 on one side that fits a hole in a block 115 that can slide in a
groove in a straight bar 116
There is a two armed lever 117, one arm on each side of its fulcrum 118
which is in a bearing on the framing, and the end of each radial arm 117 is
jointed at 119 to ears from the parallel bars 116.
At equal distances horizontally on each side of the fulcrum or shaft 118, there
is a pin or set screw 120 that screws into the framing and each set screw forms
the joint or fulcrum for one end of a radius link 121 of exactly the same length
as the radial arms or levers 117, this forms a parallel motion to keep the grooved
straight bars 116 parallel in their movements to the line between the axes of the
two set screws 120 and to each other
When the radial arms 117 are oscillated, the parallel bars 116 and thus the
ends of the former arms 20 receive a movement due to the curve described by
the ends of the radial arms which curve gives the desired shape to the teeth to
be cut There is an index scale 122 secured to each former arm, and there is an
arm 123 secured to the framing for each index scale which arms at their ends
have a zero mark opposite the index plate 122.
This arrangement is to enable the former arms to be adjusted while the bolts 112
are slack, to bring each former arm to the same distance from the central line
which is equidistant between them to suit the wheel to be cut.
When roughing the teeth of the wheel to be cut, the former arms are fixed in
position at the required distance apart and can be secured in that position by the
bolts 109, but when the former arms are to operate to shape the teeth to the
proper curve they have to begin at the point of the teeth where they are nearest
together, and are separated according to the curve required to be given to the
teeth as the cutters get nearer to the root of the teeth being cut.
The shape given to the teeth as before said, depends upon the combined move-
ment of the feed given to the carriage 32 and to the distance the former arms
are apart. These two movements are combined by transmitting the movement
of the carriage 32 when feeding to the cutters to the radial arms 117.
There is a bar 124 (see Figs. 1, 2 and 10) curved to the segment of a circle
to a radius from the centre 31 upon which the carriage turns, this segmental bar
can slide in brackets 125 secured to the framing. It also passes through bear-
ings 126 in a projection from the carriage (shown best in Fig. 10). This curved
bar 124 can be clamped or released by the set screw 127. When released the
carriage can move without moving the curved bar, when clamped the curved bar
slides in its bearings with the carriage.
One end of the curved bar has spur teeth formed in its edge that gear with
the spur teeth in a segment 128 secured to the boss of a bevel wheel 129 on a
vertical stud 130 secured in a projection from the framing (see Figs. 1 and 2).
This bevel wheel 129 gears with a bevel pinion 131 that can rotate on a stud 132
secured in a part from the framing, and this bevel pinion has an arm 133 secured
on its boss (shown on an enlarged scale detached by Fig. 3) which arm has a slot
in its lengthway for a stud 134 to be adjusted and secured therein. To ihe stud
one end of a rod 135 is jointed passing through a slot for adjusting purposes and
the other end of this rod is jointed on a stud 136 secured in a projection from
the side of the lower radial arm 117.
It will be seen (see Fig. 5) that the axial line of the fulcrums of the former
arms 20, coincide with the axial line of the vertical axis 31 upon which the
carriage turns and that these lines intersect each other in the axis of the man-
drel 55 for the wheel to be cut.
In order to produce exact work it is one essential feature of our invention
that the length between the axis of the fulcrum 106 of the former arms and
the axis of the radial arms 118 shall be four times the length exactly of the
radial arms 117 from their axis 118 to the axis of their joint pins 119. It is
another essential of our invention, that the line from the axis of the radial
arms 118 and the axis of their joint pins 119 shall be at an angle of 75 degrees

page_text: from the straight line between the axis of the fulcrum of the radial arms 118
and the axis of the fulcrum pin 106 of the former arms 20, and this
gives the correct position for the true shape of the teeth to be cut when the
cutters are operating at the pitch line position of the teeth for mitre wheels of
equal angle, but for bevel wheels of an angle greater or less than mitre wheels
a compensation has to be made as it would be inconvenient to alter the length
of the radial arms 117 to suit bevel wheels, and therefore there is a scale 137
formed on the upper parallel bar 116, or upon a plate secured thereto. The
zero mark (see Figs. 8 and 9) is or may be a point at the end of a vertical
pin 171 sliding in a bracket 172 secured to the framing.
The vertical pin 171 is lifted up after use by an helical spring 173 (see Fig. 8)
around it, in the hole in the boss through which it slides, and it is kept from
turning round and from being pushed too far upwards by the end of a small
screw that passes through the boss into a groove in the side of the sliding pin,
which is depressed when required by the knob at its upper end.
In place of the sliding pin 171 there is or may be a plate 174 having the index
marks upon it secured to the upper side of the parallel bar 116 so that one edge
will come close to a vertical plate 175 carried on the bracket 172, this plate
having a vertical line or knife edge facing the edge of the plate 175 as the zero
mark. This latter arrangement is shown in peculiar dotted line on Figs. 8 and 9.
By means of the zero mark, the parallel bars (both being connected) may be
moved and with them the radial arms 117 when they are to be adjusted to the
pitch line position, to suit the angle of the wheel to be cut.
The proportion of movement between the carriage 32 and the radial arms 117
has also to be adjusted accordingly by moving the stud 134 in the slotted arm 133
to the index mark in agreement with the wheel to be cut.
On the upper face of the bed plate 35 for the carriage, there is also an
index 138 for adjusting the position of the carriage and the zero mark for this
index is on a bracket 139 secured on the edge of the carriage see Figs. 2 and 5.
In Fig. 1, the stud 134 in the slotted indexed lever 133 is supposed to be
secured at the mark upon it for mitre wheels (450) and the slide block 115 is
also adjusted to the corresponding mark for such wheels.
These last two scales or indexes are arrived at by calculation by the formula
and explanation given below.
To produce curves of involute teeth according to this invention and to the
prevailing practice, the angle of the radial arm 117 should always remain at 75
degrees to the line joining the radial arm and former arm centres, and the length
of the radial arm 117, should vary so as always to be one fourth of the pitch
line radius of a spur wheel having the same developement of teeth as the bevel
or mitre wheel to be cut.
For mitre wheels one fourth of the pitch line radius just referred to is also
one fourth of the distance between the centre or axis 118 of the arm and the
centre 106 of the former arm (which distance will be hereinafter referred to and
represented by S) so that if the slide block 115 in the parallel bar 116 is set at 754°
to the line of centres of the radial arm and former arm for the pitch line position,
the movement given to the former arm by the radial arm through the parallel bar
and slide block will produce the correct involute curve on the mitre blank to
be cut.
The movement of the former arm 20 is as above explained, controlled by the
carriage 32 carrying the blank wheel shaft on which the bevel or mitre wheel
to be cut is secured.
For mitres, the movements of the parallel bar moving on the slide block
actuated by the radial arm 117 of the length (which is fixed) and of the
S
carriage at a radius of S. inches from the centre 31 of the carriage; are equal.
If the length of the radial arms were adjustable, the same relation would hold
good for all bevel wheels.

page_text: required radius) for all bevel wheels (including mitres) is obtained by the formula.
(a).
Tangent of the cone angle of required wheel x S
Length of radial crm.
4
To compensate for not altering the radius of the radial arm the movement of
the parallel bar 116, (which is actuated by the radial arm 117) is lengthened
when the pitch cone angle below 45° and shortened when bevel wheels above 45°
are to be cut. At the fixed radius of a length of movement is fixed upon
4
through an are having a versed sine of say H inches and then is found the length
of are having a versed sine of the same H inches in a circle of the required radius.
This will give the required movement of the parallel bar at the fixed radius
S
of see Fig. 13.
S
=
12 inches
The versed sine H fixed upon for any particular machine (which is constant
for such machine) is such as to give a curve suitable to the tooth of a
wheel or pinion of the greatest ratio (the proportion between pinion and wheel)
that can be cut in such machine, for example if S be 50 inches
(the radial arm or lever) H versed sine fixed upon 1.4 inches for the arc, the
chord M of which is consequently 11 inches, this will give a suitable curve for
the teeth of a wheel of the greatest ratio that can be cut in such machine. If a
pinion be 4 inches and the wheel 16 inches pitch diameter, the ratio is 4 to 1.
==
4
The adjustment is obtained by a scale or index on the slotted lever 133 shown
detached and on an enlarged scale in Fig. 3, this scale or index giving a correct
proportion of movement between the parallel bar 116 and carriage 32 on which
the blank wheel to be cut is mounted.
$
4
If M be the chord subtending an are having a versed sine of H inches in a
circle of inches radius. N be the chord subtending an arc having a versed
sine of H inches in a circle of the required radius. L be the distance of the
connecting rod pin 134 in the slotted lever 133 from the centre 130 about which
the slotted lever 133 oscillates, when the movement of the parallel bar and the
carriage at S inches from the centre 31 are equal i.e., for mitres of 45° pitch
cone.
ML
If X be the required distance of the connecting rod pin 134 from the oscillating
centre 31 for bevels of say y° pitch cone, it is obtained by the formula (b) X= N
Keeping the radial arm fixed in length (as in the machine shown) does not
allow it to remain at 751° to the line of centres and necessitates a compensation
so as to reproduce the same effect.
This is obtained by shifting the parallel bar 116 on the sliding block 115
according to the scale or index upon the parallel bar (shown best in Fig. 9) which
gives the correct position of the slide block in the parallel bar for different angles
of the bevel wheels when the cutting tool is on the pitch line of the wheel to
be cut.
This scale or index upon the parallel bar for different cones or angles of wheels
to be cut depends upon the formula (c) D
(see Fig. 13) where A is half
1
BC
Α
the length of the chord subtending an are having a versed sine of H inches on a
circle formed with radius correct for the tooth curve of the wheel for say y° of
pitch cone angle.

page_text: S
inches in a circle of
inches radius (correct for mitres).
4
B=the arc subtending 1410 (the difference between 750 and 90°) on a circle
of the correct radial (obtained by formula a) arm for the curve of the tooth of a
wheel having y degrees of pitch cone angle.
D= the arc subtending the angle contained between the correct position of the
radial arm and a line perpendicular to the line of centres (see diagram Fig. 13).
There is a tool box or holder on each former arm 20, as shown in Figs. 4 and 5,
both are alike except one is reversed to the other.
141 is a base secured by bolts 142 to the slide 18 on each former arm 20, the
heads of the bolts passing into an under cut slot 143 in the lengthway of the
slide, so that the tool box can be adjusted to the wheel to be operated upon.
This base is formed with two ears for a joint pin 144 fitting bushes 145 in the
holes in the ears, and passes through a projection from another part 146 which
is thus hinged to the base 141.
To the part 146 another part 147 is secured by two set screws 148 screwing
into holes in the part 146 through slots to allow it to be adjusted vertically, and
in this part 147 a dovetail recess 149 is formed at an angle for the cutting tool
(not shown in Fig. 14).
The object of this tool holder is to hold the cutter in the correct position
when cutting, but during the back stroke after cutting to slightly withdraw the
cutter from the work so that its edge is clear during the back stroke as this
produces more satisfactory work and keeps the cutter longer sharp. The part 146
and its attachment rock on the joint pin 144. The tool box is shown in the cutting
position, a projection from the part 146 rests against the face of the base part 141
at 150, but during the back stroke when not cutting, the part 146 is separated
from the base part at 150 and this moves the cutting point of the cutter 151 in,
the curve represented by the arrow on Fig. 15, so that it is slightly withdrawn
from the surface last cut.
This movement is effected by a shaft 152 in bearings in the base part 141 which
shaft has a tube 153 secured to it by a pin 154.
One side of this tube 153 is flat and is just clear of the face opposite to it
on the part 146 when the tool is cutting, but when the shaft 152 is oscillated to
bring the round part of the tube against the flat face on the part 146 it is
pushed outwards.
The shaft 152 is oscillated by an arm 155 secured by a pin 156 on its upper
end, and at or near the end of the cutting stroke this arm 155 comes against a
pin 157 adjustable on a rod 158 carried in brackets 159 from the former arm 20
(see Figs. 1 and 4) and this gives the desired oscillation to the shaft 152, the
arm 155 being acted upon at or near the end of the return stroke by another
adjustable pin 157 on the rod 158 to bring it to the cutting position and so for
cach double stroke.
The oscillation when the arm 155 is reversed is assisted by an helical spring 160
on a pin 161 secured in the base part 141 against which one end of the spring
abuts, the other end coming against an arm 162 from the part 146..
Vertical adjustments are given to the box carrying the cutter by a set screw 163
screwing into a hole in the part 146 the head of this set screw being grooved
so that a fork comes into the groove from a bracket 162 secured by screws to
the part 147. When adjustment is taking place, the set screws 148 are slack and
when adjusted they are tightened.
The cutter 151 is made of steel of a triangular cross section forming a dove
tail to fit the dove-tail recess 149 in the part 147. The top of the cutter is
grooved to a curve, to fit a corresponding curved edge of a screw wedge bolt 165
flat on the opposite side.
When the cutter is in position in the holding cavity, the wedge bolt 165 is
drawn up tight by the screw nut on its end, the screwed end of the bolt passing

page_text: through a part 166 in which there is a set screw 167, the point of which acts
against the back end of the cutter, and thus holds it firm in the dove tail cavity.
The cutter bar is or may be of uniform cross section, but has a part on one
side 168 (opposite to the cutting side) removed to give clearance, and when
hardened it is sharpened by grinding off the front end (169 Fig. 18) By grind-
ing off the cutter in the line 170 Fig. 18, a more or less wide or narrow cutting
edge is obtained as desired.
In the machine acting upon the principle of that described in the said Buck's
British specification and in our herein described machine, the cutting of the teeth
commence at the tips of the teeth, and each tooth of the wheel has the same
cut, the wheel being moved after each cut until all the teeth of the wheel are
cut to the same depth.
But our invention is applicable when one tooth of a wheel is cut from its tip
to its root before another tooth is operated upon.
The invention is applicable to other machines for cutting the teeth of bevel
wheels, besides the said Buck's machine.
Having now particularly described and ascertained the nature of our said
invention, and in what manner the same is to be performed, we declare that what
we claim is :-
"
1. The cutting or shaping of the teeth of mitre and bevel wheels without
shapers" or templates, by the combination of a radial arm with a lever or arm
carrying the planing cutter in the manner and arranged and having the ratios
one to the other substantially as hereinbefore described and illustrated by the
drawings.
2. The cutting or shaping of the teeth of mitre and bevel wheels on both sides
simultaneously without shapers or templates, by the combination of two radial
arms with two levers or arms each carrying a planing cutter in the manner and
arranged and having the ratios one to the other substantially as hereinbefore
described and illustrated by the drawings.
3. The combination of the mechanism referred to in Claims One and Two with
the carriage substantially as hereinbefore described and illustrated by the
drawings.
4. The combination with the former arm or former arms and radial arm or
arms of a bar or bars (herein before termed the parallel bar) kept parallel sub-
stantially as and for the purpose hereinbefore described and illustrated by the
drawings.
5. The combination with the mechanism of scales for adjusting it to cut mitre
wheels and bevel wheels of various angles substantially as herein before described
and illustrated by the drawings.
6. The combination of the mechanism for changing the position of the cutter
or cutters for cutting or shaping the teeth of mitre and bevel wheels without
shapers or templates with the mechanism described in the Complete Specification
of John Buck No. 8418 of 1895 modified, substantially as hereinbefore described
and illustrated by the drawings.
7. The combination of mechanism to stop the feed to the cutters at the point
fixed upon automatically substantially as herein before described.
8. The combination and arrangement of tool holding mechanism substantially
as and for the purpose hereinbefore described and illustrated by the drawings.
9. The combination and arrangement of mechanism substantially as and for the
purpose hereinbefore described and illustrated by the drawings.
Dated this Fourth day of April 1900
PETER. J. LIVSEY,
Agent.