IMPROVEMENTS IN MACHINERY OR APPARATUS FOR MOULDING TOOTHED WHEELS AND OTHER LIKE ARTICLES, PARTS OF WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO OTHER SIMILAR PURPOSES
Year: 1877

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields, in the
County of Middlesex, Gentleman, for the Invention of "IMPROVEMENTS IN
MACHINERY OR APPARATUS FOR MOULDING TOOTHED WHEELS AND OTHER
LIKE ARTICLES, PARTS OF WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO
OTHER SIMILAR PURPOSES." A communication from abroad by Jules Cardailhac,
of Poria in the Republic of France
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents on the 22nd September 1877.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR MOULDING
TOOTHED WHEELS AND OTHER LIKE ARTICLES, PARTS OF WHICH IMPROVEMENTS ARE
ALSO APPLICABLE TO OTHER SIMILAR PURPOSES." A communication from abroad by
Jules Cardailhac, of Paris, in the Republic of France.
This Invention relates partly to the moulding in sand of the teeth of toothed<
wheels and of other like articles, and it has reference to that description of
machinery employed for this purpose which is composed of the two following
constituent parts, viz :-
1st. A dividing apparatus.
2nd. An arm carrying the pattern, the motion of which is regulated by the
dividing apparatus.
The Invention consists of improvements in both parts of the said machinery,
the first part of such improvements being equally applicable to all purposes for
which a dividing apparatus is required.
The dividing apparatus, constructed according to the first part of this Invention,
is based on the principle already adopted in machines for cutting out the teeth of
toothed wheels, but it has applied to it improvements, having for their object :
obviating the errors which are liable to occur in the division, in consequence of

page_text: the play which after a time takes place between the different parts of a dividing
apparatus.
In carrying out this part of the Invention a flat table is employed, fixed upon
a partially sheathed plank or webbed bearer supported by two trestles, which table
carries bearings for the reception of the spindle of an endless screw or worm, and a
worm wheel engaging therewith. The hub of the worm wheel is prolonged in the
form of a friction roller, the rotation of which imparts motion to a friction wheel
of greater diameter than the roller; the said wheel being keyed upon a rotatory
shaft carrying the trammel or apparatus, which serves to form the bed of the wheel
in which the division and shape of the teeth is to be moulded, and also carrying the
improved apparatus, herein-after described, for moulding the said teeth.
The friction roller and wheel are brought into contact by means of screws acting
upon a sliding bearing carrying the spindle of the wheel. Motion is imparted to
this friction wheel by a crank handle which turns a spindle, carrying a pinion
which is in gear with an intermediate wheel, imparting motion to another wheel
fixed on the spindle of the endless screw. The combination of these three wheels
(which may be changed to vary the proportion of the speed according to the division
to be effected) causes the worm wheel, and consequently the roller, to describe arcs,
corresponding to one or more revolutions of the handle."
It is obvious that as the shaft carrying the moulding apparatus is caused to
rotate by the action of the roller, such shaft with its apparatus will describe similar
arcs, whereby the teeth of the wheel will be moulded in succession in accordance
with the movements of the dividing apparatus.
Heretofore, in the construction of dividing apparatus, it has been found necessary
to employ worm wheels of considerable diameter, and the machines are consequently
heavy, difficult to construct, and very costly; but the employment of friction
rollers or friction wheels, according to this Invention, admits of divisions of great
precision being obtained with a worm wheel of small diameter.
The second part of this Invention consists of a universal arm or carrier, which is
constructed in the following manner:-A double socket formed by two tubes placed
with their axes at right angles is fitted, so as to be free to slide upon the vertical
shaft carrying the apparatus, and through the horizontal portion of the socket is
passed a hollow iron tube, covered with wood to prevent it from bending, which
tube is capable of sliding through the socket for its entire length. The tube has
pivotted to it at one end a carrier, to which is fitted a slide, carrying a segmental
pattern for forming the tooth.
The slide is so arranged as to be free to move vertically under the action of a
screw, and also so as to be capable of assuming any angle of inclination requisite
for the angle formed by the tooth of the wheel which it is desired to mould or
adjust.
The carrier is also capable of being turned on its pivot for the facility of making
helical teeth, whilst it is adjustable relatively to the centre of the apparatus to suit
the radius of the wheel to be moulded.
The machine operates in the following manner :-The bed in which the teeth are
to be formed, having been properly prepared, a toothed pinion, having the required
number of teeth, according to the division which it is desired to obtain, is in the
first place fixed on the spindle of the endless screw in the dividing apparatus, and
the position of the first tooth is determined in relation to one of the arms of the
wheel. The segmental pattern is placed in the position to be occupied by the first
tooth, and the sand is rammed round the pattern, after which the latter is raised by
turning the screw of the carrier. The crank handle of the dividing apparatus is
then turned the required number of revolutions, whereby the segmental pattern is
moved a distance exactly equal to the interval between two teeth and the screw,
being then turned in the reverse direction, the segmental pattern is lowered for
forming the second tooth, and so on in succession for the whole number of teeth
which the wheel is to contain.
The dividing apparatus, which may be readily moved, can also be employed with

page_text: advantage for the purpose of (verifying the exactness of the division, either of the
teeth of old patterns which have been distorted by time and use, or the recesses or
mortises of the wooden cogs of cog wheels, as well as for marking the axes of
cast-iron teeth when it is required to cut the teeth either by hand or in a shaping
machine.
This improved dividing apparatus may also be advantageously applied to
machines for cutting the teeth of metal wheels or wooden cogs.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Henry Johnson in the Great Seal Patent Office on the 22nd
March 1878.
JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
Gentleman. "IMPROVEMENTS IN MACHINERY OR APPARATUS FOR MOULDING
TOOTHED WHEELS AND OTHER LIKE ARTICLES, PARTS OF WHICH IMPROVEMENTS ARE
ALSO APPLICABLE TO OTHER SIMILAR PURPOSES." A communication from abroad by
Jules Cardailhac, of Paris, in the Republic of France.
The said Invention relates partly to the moulding in sand of the teeth of toothed
wheels and of other like articles, and it has reference to that description of
machinery employed for this purpose which is composed of the two following
constituent parts, videlicit:-
First. A dividing apparatus.
Second. An arm carrying the pattern, the motion of which is regulated by the
dividing apparatus.
The said Invention consists of improvements in both parts of the said machinery,
the first part of such improvements being equally applicable to all purposes for
which a dividing apparatus is required.
And in order that the said Invention may be fully understood, I shall now pro
ceed more particularly to describe the same, and for that purpose shall refer to the
several Figures on the annexed Sheet of Drawings, the same letters of reference
indicating corresponding parts in all the corresponding Figures.
Figure 1 of the accompanying Drawings represents an elevation, partly in
section, of a machine constructed according to the said Invention, as applied to the
dividing and moulding in sand of the teeth of toothed wheels; Figure 2 is a plan
of the same, corresponding to Figure 1.
Figure 3 illustrates the application of the machine for adjusting or correcting the
division of the teeth of a toothed wheel.
Figures 4, 5, and 6 illustrate in sectional elevation, plan, and elevation, respec-
tively, another modification of the apparatus.
The dividing apparatus, constructed according to the first part of the said Inven-
tion, is based on the principle already adopted in machines for cutting out the teeth
of toothed wheels; but it has applied to it improvements having for their object
obviating the errors which are liable to occur in the division, in consequence of the
play which after a time takes place between the different parts of a dividing
apparatus.
P is a flat table fixed upon a bearer M, supported by two trestles T, which table
carries bearings for the reception of the spindle of an endless screw or worm A and

page_text: of a worm wheel B engaging therewith. The hub of this worm wheel is prolonged
in the form of a friction roller at C, the rotation of which imparts motion to a
friction wheel D of greater diameter than the roller, the said wheel being keyed
upon a rotatory shaft E for carrying the plain trammel or apparatus, which serves
to form the bed of the wheel in which the division and shape of the teeth is to be
moulded, and also for carrying the improved trammel or apparatus, herein-after
described, for moulding the said teeth.
The friction roller C and wheel D are brought into contact by means of screws
acting upon a sliding bearing carrying the spindle of the wheel D. Motion is
imparted to this friction wheel by a crank handle R, which turns a spindle carrying
a pinion F, which is in gear with an intermediate wheel F¹, imparting motion to
another wheel F fixed on the spindle of the endless screw A. The combination
of these three wheels F, F', F", (which may be changed to vary the proportion of
the speed according to the division to be effected) causes the worm wheel B, and
consequently the wheel D, to described arcs corresponding to one or more revolutions
of the handle R.
It is obvious that as the shaft E carrying the moulding apparatus is caused to
rotate by the action of the roller, such shaft will describe similar arcs to the roller,
as will also the carrier holding the pattern, and which is situate at any suitable
distance from the centre of the shaft, according to the radius of the wheel to be
moulded.
The small dimensions of the worm wheel would apparently be open to the
objection of a liability of inaccuracy in the division of a wheel of considerable
diameter.
Heretofore, in the construction of dividing apparatus, it has been necessary to
employ worm wheels of considerable diameter, and the machines are consequently
heavy, difficult to construct, and very costly; but the employment of friction
gearing, according to the said Invention, admits of divisions of great precision
being obtained with a worm wheel of small diameter. Should an error take place
between two teeth it can only be very slight, by reason of the fineness of the pitch
of the wheel, and being divided by the proportion of the diameters of the worm
wheel B and the roller C it becomes practically eliminated.
A wheel and pinion may be employed in combination with the friction wheel D
and roller C, the pitch lines of which correspond with the circumferences of the said
wheel and roller, in order to ensure their simultaneous rotation, whilst at the same
time obviating any liability to slip under the influence of a sudden jerk.
The second part of the said Invention consists of a universal trammel or carrier,
which is constructed in the following manner:-A double socket G, formed by two
tubes placed with their axes at right angles, is fitted so as to be free to slide upon
the vertical shaft E carrying the apparatus, and through the horizontal portion of
the socket is passed an iron tube H, filled with wood to prevent it from bending.
This tube, which is capable of sliding through the socket for its entire length, has
pivotted to it at one end a carrier K, to which is fitted a slide J, carrying a
segmental pattern L for forming the tooth.
The slide J is so arranged as to be free to move vertically under the action of a
screw S, and also so as to be capable of assuming any angle of inclination requisite
for the angle formed by the tooth of the wheel which it is desired to mould or
adjust (see Figures 1 and 3).
The carrier is also capable of being turned on its pivot 1, for the facility of
making helical teeth. The screw S is caused to rise and lower as required the
slide J, holding the segmental pattern L by the act of operating a crank handle U.
The machine operates in the following manner:-The bed in which the teeth
are to be formed having been properly prepared, a toothed pinion F, having the
required number of teeth according to the division which it is desired to obtain,
in the first place fixed on the spindle of the endless screw A in the dividing
apparatus, and the position of the first tooth is determined in relation to one of the
arms of the wheel. The segmental pattern L is placed in the position to be occupied

page_text: by the first tooth, and the sand is rammed round the pattern, aftor which the latter
is raised by the act of turning the screw S of the carrier. The crank handle R of
the dividing apparatus is then turned, whereby the segmental pattern is moved a
distance exactly equal to the interval between two teeth, and the screw S being
then turned in the reverse direction the segmental pattern is lowered into the
position for forming the second tooth, and so on in succession for the whole
number of teeth which the wheel is to contain.
Figures 4, 5, and 6 illustrate a modification of the arrangement herein-before
described, whereby the trestles and support for sustaining the apparatus are dis-
pensed with. In this arrangement the motion of the travelling part of the apparatus
is not effected by means of a friction wheel keyed upon the vertical shaft of the
arm, but on the contrary, the whole of the dividing mechanism turns round a
friction wheel A, keyed immoveably upon a fixed shaft B, which is supported
vertically in a socket C imbedded in the ground. On the shaft B is fitted, so as to
be capable of turning freely, a socket E, which serves to support the whole system,
the said socket carrying a radial arm F formed by two solid or hollow metal rods,
at the extremities of which the pattern holder K is attached.
As the friction is greater in this arrangement than in the one previously described,
the friction wheel A and roller G are provided respectively with a toothed wheel H
and a pinion I, the pitch lines of which are of exactly the same diameter as the
circumferences of the two corresponding rollers. By these means the liability is
obviated of the smooth surface of the friction wheel A and roller G slipping in case
of an undue friction of the socket E upon the shaft B, and upon the collars J¹, K',
which support it on the said shaft.
In case the pitch of the teeth of the wheel and of the pinion is wanting in
mathematical precision, the contact of the friction wheel A and roller G will correct
this influence, and prevent the backward slip which might result from the wearing
away and play existing between the teeth of the wheel and pinion.
The parts shewn in Figures 4, 5, and 6, and not particularly described, will be
understood from the description given of the arrangement illustrated in Figures 1
and 2 without further explanation.
In addition to its use for moulding toothed wheels and other articles of a similar
description, the dividing apparatus, which may be readily moved, can also be
employed with advantage for the purpose of verifying the exactness of the division
either of the teeth of old patterns which have been distorted by time and use, or
the recesses or mortises of the wooden cogs of cog wheels, as well as for marking
the axes of cast-iron teeth when the manufacturer, not having a cutting machine, is
obliged to cut the teeth either by hand or in a shaping machine.
This improved dividing apparatus may also be advantageously applied to machines
for cutting the teeth of metal wheels or wooden cogs.
Having now described and particularly ascertained the nature of the said
Invention and the manner in which the same is or may be used or carried into
effect, I would observe in conclusion that what I consider to be novel and original,
and therefore claim as the Invention secured to me by the herein-before in part
recited Letters Patent is,-
First. The employment of friction gearing in combination with an endless screw
or worm and a worm wheel for transmitting the motion of the dividing apparatus,
substantially in the manner and for the purposes herein-before described.
Second. The universal trammel or apparatus for moulding toothed wheels and
for other similar purposes, the said apparatus consisting of a rotating shaft or axis,
on which is fitted, so as to be capable of sliding, a double socket, through which
passes a rod terminated by the holder supporting the segmental pattern, all sub-
stantially as herein-before described, and illustrated by the accompanying Drawings.
Third. The arrangement of the segmental pattern and of the screw holder which
serves for its manipulation, enabling the pattern to be raised or lowered and inclined
in two directions, substantially as and for the purposes herein-before described, and
as illustrated by the accompanying Drawings.

page_text: Fourth. The combination of the dividing apparatus and the universal trammel or
carrier, both constructed and arranged so as to operate substantially in the manner
and for the purposes herein-before described, and as illustrated by the accompanying
Drawings.
In witness whereof, I, the said John Henry Johnson, have to this my
Specification set my hand and seal, this Twenty-first day of March, One
thousand eight hundred and seventy-eight.
J. HENRY JOHNSON. (L.S.)