Improvements in Apparatus for Cutting the Teeth of Gear Wheels and the like.
Year: 1898

page_text: Date of Application, 25th Jan., 1898-Accepted, 18th June, 1898
COMPLETE SPECIFICATION.
Improvements in Apparatus for Cutting the Teeth of Gear Wheels
and the like.
I, STANISLAW STÜCKGOLD, of 16,
Engineer, do hereby declare the
the same is to be performed, to be
by the following statement :-
Zurawia, Warsaw, in the Empire of Russia,
nature of this invention and in what manner
particularly described and ascertained in and
This invention has for its object a machine designed for cutting the teeth o
cog wheels, the teeth according to this invention being given each the form of an
angle or V for the purpose of giving a better hold or engagement. The machine
can, like other cutting machines, cut the teeth directly out of solid material, or
subsequently cut the teeth of cast wheels and bars.
In the accompanying drawings,
Figure is a side view of a form of construction of the tooth cutting
machine;
Figure 2 a section at right angles to Figure 1.
Figure 3 shows a portion of the periphery of a wheel provided with angle teeth
in accordance with the invention.
The part of the present machine which forms the actual object of the invention
is shown in the lower part of Figure in side view. In order to allow of the
mode of working of the machine being better understood it is necessary to also
describe those parts of the same which are not the object of the present
invention.
a is the cutter which is operated by two worm wheels b c. A shaft e is rotated
by means of a stepped pulley d, Figure 2, and an endless screw f is mounted on
the shaft e to revolve a shaft i by means of a worm wheel g and bevel gearing h,
which conveys its movement by means of spur wheels kl, two shafts m n and
bevel gearing o to a spur wheel p. The rotary movement of this wheel is conveyed
by means of spur wheels q r and a shaft & to a pinion t. The wheels p q r must
be removable in order that the angle to which the teeth of the wheel or the like
to be formed may be altered as desired. A rack gear y is arranged to act in
conjunction with a rack u constructed like a ladder with round teeth which are
engaged by the pinion t which latter engages first above and then below, thus
a to-and-fro motion.
giving the rack u
Several teeth of this rack 24
are extended laterally beyond the width of the bar in the manner shown
in Figure 2 to engage eccentrically in discs vwhich may thus be termed
crank discs. These crank discs v are mounted revolubly on pivots x on the
which all
rack y and are preferably formed
engage
in a rack w longitudinally movable on the rack y. The rack w has for its
object to prevent any small individual turnings of the wheels v which might take
place at certain times. The geometrical axes of rotation x of the wheels v must
all lie in one plane and the geometrical axis of the wheel t must also lie in this
plane and parallel to the axis x. The pivots of the cams rest in the rack y as
aforesaid which is guided in a dovetail in the manner shown in Figure 2, and the
said rack y carries the connecting rack w by means of an under claw-like
as
cog wheels

page_text: projecting part z. The rack y is moved longitudinally to and fro, when the
machine is at work, and thereby revolves, by means of wheels a¹ b¹ c¹, a shaft d¹
which in turn revolves by means of gear wheels e¹ f¹ g¹ h¹, two shafts k¹ the
latter of which conveys its. movement by means of a toothed wheel 1, a large
spur wheel m³, shaft n¹ and screw o' to a face disc p' on which the wheel q¹ on
which the angle teeth are to be cut is fixed.
The machine works as follows:-
-
When the stepped pulley d, Figure 2, is rotated the support 8' travels along on the
carriage t', so that the cutter a is moved through the part of the wheel q' which
is to be operated on and thus forms entirely fresh interdental spaces or cuts or
shapes those already existing. At the same time the said wheel is slowly revolved
as the cutter is connected with it by means of the cog wheel and shaft arrange-
ment hereinbefore described in such a way as to convey movement to it so that the
cutter in reality moves in an oblique direction on the periphery of the wheel and
thus cuts a spiral groove in the same. The chief characteristic of this improved
machine consists in the circumstance that the wheel to be cut travels uninterruptedly
during the cutting in the same direction, rotating at first in the one direction and
afterwards in the opposite one so that the resulting interdental spaces do no: run
uninterruptedly from one side of the wheel to the other but turn in the middle of
the width of the wheel so that angular grooves corresponding to the desired angle
shaped teeth result. The actual object of the invention consists in the mechanism
consisting of the pinion, the ladder shaped rack u, the crank discs v and rack y,
which produce the forward and backward rotation of the wheel to be operated on,
necessary for producing the angular form of the teeth. This mechanism itself
works in the following way:-The pinion t runs on top of the ladder shaped
rack until it reaches the end of the same. As the connection of the rack u
with the rack bar y is only produced by the crank discs v, the radius of which is
equal to the radius of the pinion t, and these cranks v are turned vertically upwards
or downwards according to the direction of movement of the two racks and y,
the rack u, as soon as it is pushed forward by the pinion t will, in consequence of
the tendency of the crank discs v to rotate, be pressed firmly down into the
wheel t and thereby any further rotation of the crank discs v will be prevented. It
is possible by a suitable construction and formation of details, to maintain practically
at zero the angle at which the cranks v turn out of their vertical position under
the pull exerted on the rack, u. As the cranks are thus entirely prevented
rotating by reason of the firm engagement of the round teeth of the rack u in the
teeth of the pinion t, then so long as the pinion t has not reached the end of the
rack u, the crank discs v following the rectilinear movement of the rack u must
carry with them also the rack y on which they are pivoted. When the pinion t
reaches the end of the rack u, the latter loses its support on the said pinion t and
therefore following the pressure exerted by the wheel t on its last tooth, moves for
instance from the upper position into the lower one, being to a certain extent
swung round parallel to itself by the crank discs which are now no longer
prevented rotating. The period of this swinging round of the rack u out of the
upper into the under position and vice versa always coincides with the moment at
which the wheel or rack which is being cut inust reverse its direction of movement
in order to obtain the angular shape of the teeth. As soon as the rack u has been
swung round by means of the crank discs, the pinion t runs (without having altered
the direction of its rotation) on the bottom of the rack u, thus moving the latter
backwards until the cutter has passed over the whole width of the article which
is being operated on. The piece operated on is then, after the machine has been
stopped, turned sufficiently far to allow the cutter to come again into play, and the
operation is repeated. In order to prevent the crank discs v moving out of
parallel, for instance in consequence of the wear of the pivots, during the swinging
round of the rack u, they are formed as cog wheels which are forced by the sliding
rack w to make an exactly even movement,

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is:-
1. A machine for cutting angle teeth in which the article operated on (wheel, or
the like) and the cutter are moved in such a way that the latter, corresponding
to the desired angle of the teeth, cuts obliquely to the direction of movement of the
work piece, characterised by a rack (y) for moving the article to be operated on,
being moved alternately in one direction and the other longitudinally by means of
a pinion (t) which runs always in a constant direction of rotation simultaneously
with the cutter (a), the said pinion (t) for said purpose engaging alternately on the
upper and under side of a ladder shaped rack (u), the power-conveying connection
of the two racks (y and u) being effected by means of crank discs (v) revolubly
mounted on the one rack (y) in the plane of the axis of the pinion (t) and con-
nected by their crank pins with the other rack (n), which crank discs (v) by the
engagement of the rack (u) with the pinion (t) are held at right angles to the
direction of travel of the racks (u and y) and on the passage of each end tooth of
the ladder rack (u) over the pinion (t) are turned in a semi-circle, the rack (u)
making a corresponding but parallel movement, substantially as hereinbefore
described.
2. A machine for cutting teeth such as hereinbefore described, characterised by
the crank discs (v) being formed as cog wheels and connected with one another by
a common rack bar (w) with the object of producing an exactly simultaneous
movement substantially as described.
3. A machine for cutting angle teeth, characterised by the reversal of movement
of the article operated on (cog wheel, or the like) taking place by means of suitable
mechanical apparatus always at the moment or period of time at which the cutter
has reached the centre of the piece operated on, substantially as herein before
described.