IMPROVEMENTS IN DIFFERENTIAL GEARING APPLIED TO ELECTRIC MOTORS AND VEHICLES
Year: 1883

page_text: LETTERS PATENT to Frank Wynne of 4 Westminster Chambers in the City
of Westminster, Civil Engineer, for an Invention of IMPROVEMENTS IN
DIFFERENTIAL GEARING APPLIED TO ELECTRIC MOTORS AND VEHICLES
PROVISIONAL SPECIFICATION left by the said Frank Wynne at the Office
of the Commissioners of Patents on the 15th May 1883.
FRANK WYNNE of 4 Westminster Chambers in the City of Westminster, Civil
Engineer, " IMPROVEMENTS IN DIFFERENTIAL GEARING APPLIED TO ELECTRIC
MOTORS AND VEHICLES,"
"
Whereas it is often convenient or requisite in the case of electric motors to drive
by or from them by means of suitable gearing at a speed lower than that of the
motor. I effect this by taking any convenient motor or motors driven by
electricity (hereinafter called motor or motors) and apply to it or them in a suitable
manner a differential gear of such a form as to obtain two revolving drums or discs
(hereinafter called discs) and made to revolve in convenient proximity to one
another but in opposite directions, and in contact with both discs I employ a
conveniently shaped appliance which I call a 'carrier," being a wheel or cylinder
or conveniently shaped cone, or stepped cone, or other body of suitable construction
and material capable of revolving round its own axis, and which, either by friction,
or by means of teeth, is caused to revolve by contact with the two discs. This
Gear or gearing is hereinafter referred to as Gear I or driving gear. I connect
the two rotating discs together by means of another set of gearing bereafter referred
to as Gear II or regulating gear, in such a manner that they shall rotate (relatively
to a fixed point) in some definite ratio for the time being, this ratio inay in some
cases be unity, that is, both may make the same number of revolutions (of course
in opposite directions) in a given time, but more often I gear them so that one
makes a different number of revolutions from the other in a given time. By
suitably proportioning the diameter of the discs, and their rate of revolution, and
where necessary the diameter of that part of the carrier with which they
respectively are in contact, I obtain that, when the above described gearing is
Pin JI

page_text: connected, the axle of the carrier (although the discs rotating it are moving at a
high speed) moves round an axis which is the same or nearly the same as that of
the discs, at any relatively slow rate of revolution, and in either direction as
arranged for it being understood that the discs are so mounted that the carrier
may under the bereinbefore described conditions, move round between them.
The axle of the carrier or carriers (for several may be used in the space between
the discs) I attach to a slow motion axle or to a disc or other convenient device
which may be attached by a clutch or otherwise to a slow motion axle, whose axis
is the same, or nearly the same, as the axis of the rapidly rotating disc.
The regulating gear II I often make similar to gear I, though not necessarily of
the same size or proportion, and in this case I sometimes refer to them collectively
as gear." And I sometimes effect the differential movement by so connecting by
friction or other gear the slow motion shaft of each gearing that they shall both
"
move:
I sometimes effect this by mounting two similar gears on parallel or nearly
parallel shafts, which shafts are suitably geared together by friction or other gearing
so that they may move or tend to move together. I also gear together the quicker
motion disc of one gear, to the slower motion disc of the other gear, and vice
versa.
I sometimes effect this by arranging both gears on one axis, but in this case
the slow motion shaft of one, say gear II must move independantly of the slow
motion shaft of the other gear, say gear I, as for instance concentrically round it
and in the opposite direction, and this slow motion shaft of gear II I connect by
suitably proportioned gear to another shaft parallel or nearly parallel to the first,
the two shafts being suitably geared together so that they may move or tend to
move together.
"
The same arrangement I sometimes employ in more than two axles which may
be arranged parallel or nearly so.
In the case of the application of this gearing to tramcars and similar vehicles
or rails or roads, I often find it convenient to apply it to two parallel axles of the
same vehicle, and to effect the gearing between the two axles, so that they shall
move together by means of the friction of the wheels fixed to these axles on the
rail or road way, and in this, and in similar cases, I sometimes fix only one wheel
on each axle, one wheel on one end of one axle and one wheel on the other end of
the other axle, so as to get the axles conveniently close together, and I sometimes
with these improvements use a bogey frame.
But I do not limit myself to having only one wheel on each axle or to effecting
the gearing between the two axles by means of the friction of the wheels on the
road.
If the above mentioned wheels are of the same diameter, and the gear on the
one axle is the same as the gear on the other axle, the two slow motion shafts
move at the same speed so long as there is no slip between the axles, and wheels,
and between the wheels and the rails.
The rotation of the discs I obtain sometimes, by causing the armature of the
motor to revolve in one direction, and the field magnets to rotate in the opposite
direction, and attaching the armature to one disc or discs and the field magnets to
the other.
Sometimes I rotate each disc by means of a separate motor or motors in which
the armature only revolves or the field magnet only revolves.
Sometimes I employ only one rotating part of one motor to effect through
suitable gearing the rotation in opposite directions of two discs and sometimes I
effect the rotation of two sets of rotating discs or gear on parallel axles from one
rotating part of one motor.
I sometimes arrange the differential movement by fixing or anchoring the axes
of the carriers of one gear, those of the other gear being carried round.
When arranging the differential movement in this manner, and with parallel
axles, the axes of the carriers (or what is substantially. the same thing its slow

page_text: motion shaft) being fixed, no gearing between it and the slow motion shaft of the
other gear is necessary.
I sometimes use the carrier or carriers as a commutator or commutators by
employing it or them, or suitably insulated parts of, or attachment to it or them,
as conductor of the electric currents between the armature and the field coils
(where such and not permanent magnets are employed) and when necessary with
the main electric circuit, the discs in this case being also supplied with suitabl
arranged and insulated conductors, or having such attached to them.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Frank Wynne in the Great Seal Patent Office on the
15th November 1883.
FRANK WYNNE of 4 Westminster Chambers in the City of Westminster, Civil
Engineer "IMPROVEMENTS IN DIFFERENTIAL GEARING APPLIED TO ELECTRIC
MOTORS AND VEHICLES
"
Whereas it is often convenient or requisite in the case of electric motors to drive
by or from them by means of suitable gearing at a speed lower than that of the
motor. I effect this by taking any convenient motor or motors driven by
electricity (hereinafter called motor or motors) and apply to it or them in a suitable
manner a differential gear of such a form as to obtain a pair or pairs of revolving
drums or discs (hereinafter called discs) and made to revolve in convenient
proximity to one another but in opposite directions, and in contact with both
discs I employ conveniently shaped appliances which I call a "carrier " or "carriers"
being a wheel or cylinder or conveniently shaped cone or stepped cone, or other
body of suitable construction and material capable of revolving round its own axis,
and which, either by friction, or by means of teeth, is caused to revolve by contact
with the two discs. This gear or gearing is hereinafter referred to as Gear I or
driving gear. I sometimes connect the, two rotating discs together by means of
another set of gearing hereafter referred to as Gear II or regulating gear, in such
a manner that they shall rotate (relatively to a fixed point) in some definite ratio
for the time being. This relative motion of the two discs may be produced by
simply driving one disc with a more powerful motor than the other, or by passing
more current through the one motor than the other, or, by mechanical means, by
a friction gearing or connection retarding the motion of one motor relatively to
that of the other. This ratio may in some cases be unity, that is both may make
the same number of revolutions (of course in opposite directions) in a given time,
but more often I gear them so that one makes a different number of revolutions
from the other in a given time.
By suitably proportioning the diameter of the discs, and their rate of revolution;

page_text: and where necessary. the diameter of that part of the carrier with which they
respectively are in contact I obtain that whether by means of two gears or by
means of two motors of different strengths or driven by currents of different
strengths, the axle of the carrier (although the discs rotating it are moving at a
high speed) moves round an axis which is the same or nearly the same as that of
the discs, at any relatively slow rate of revolution, and in either direction as
arranged for it being understood that the discs are so mounted that the carrier
may under the hereinbefore described conditions, move round between them.
The axle of the carrier or carriers (for several may be used in the space between
the discs) I attach to a slow motion axle or other convenient device which may be
attached by a clutch or otherwise to a slow motion axle, whose axis is the same
or nearly so, as the axis of the rapidly rotating disc.
The annexed sheet of drawings illustrates the mode of performing my invention
but I do not restrict myself to the exact modes shown as they may be performed
in other ways without departing from the 'nature of my invention in which Figs
1. 2. 3. 4 and 5 are plan views-like figures represent like parts.
The two rotating discs are every where designated by the letters a and b and the
carrier or carriers by c in cases where both Gear I and Gear II are employed as
above the same letters are used but with the addition of a dash thus α₁ b₁ q₁.
In
The motor or motors is designated by the letter M the armature by d and the
field magnets by e. The slow moving shaft or shafts by f f₁ respectively.
some cases as in Fig 5 the movements in opposite directions of the two discs is
obtained by making the armature d move in one direction and the field magnets e
in the other but I do not claim this motion of the armature and field magnets in
opposite directions as new-in this figure a and b, are moved by the rotation of e
to which they are mechanically connected-and b and a₁ by the rotation in the
opposite direction of d to which they are mechanically connected-The axis of
the carriers are connected through the arms g and g₁ to bosses h h₁ and these can
be respectively connected rigidly to f by clutches, or other convenient attachment
not shown in the drawing-but when one clutch is connected the other must be
. loose and when the clutch attaching say h₁ to f is connected-the carrier c and
arm g must be fixed say to the body of a tramcar and h free from f.
I sometimes mount two similar gears on parallel or nearly parallel shafts which
shafts are suitably geared together by friction or other gearing so that they may
move or tend to move together.
In some cases of the application of this gearing to tram cars and similar vehicles
on rails or roads, I find it convenient to apply it to two parallel axles of the
same vehicle, and to effect the gearing between the two axles, so that they shall
move together by means of the friction or toothed connection of the wheels fixed
to these axles on the rail or roadway and in this, and in similar cases, I sometimes
fix only one wheel on each axle, one wheel on one end of one axle, and one wheel
on the other end of the other axle, so as to get the axles conveniently close
together, and I sometimes with these improvements use a bogey frame. This
arrangement is illustrated in Fig 2 the bogey not being shown
But I do not limit myself to having only one wheel on each axle or to effecting
the gearing between the two axles by means of the friction of the wheels on the
road.
If the above mentioned wheels are of the same diameter and the gear on the
one axle is the same as the gear on the other axle, the two slow motion shafts
move at the same speed so long as there is no slip between the axles, and wheels
and between the wheels and the rails.
This arrangement is illustrated in Fig 1-Fig 3 illustrates a further arrange-
ment in which by suitably proportioning the connecting wheels 1 m l₁ m₁ the
axle and carriers c₁ may be held fixed.
In all the above and following figures J J represent the wheels of a tramcar.
But instead of tramcar wheels it may serve to represent the slow motion of other
apparatus such as a pulley or gear requiring to be moved at a slower motion than

page_text: the motor from which it obtains its motion. In all the above arrangements only
one motor is absolutely necessary.
Fig 4 illustrates an arrangement of two motors M and M, connected up in.
parallel circuit to the same source of electricity or each to a separate source.
The field magnets e may be excited separately or from either of the motors in
any convenient way.
The two motors are arranged to rotate when connected up in opposite directions
and if they are connected in parallel to the same source of electricity the required
difference of speed of rotation may be conveniently obtained by either inserting
an electrical resistance into the circuit of the one which it is desired to retard or by
mechanical friction applied to it or to a moving part connected with it or by a
combination of both these methods.
If the two motors are on separate circuits the current flowing through them
can be altered in any convenient manner so as to produce the required difference
of speed between the two discs, and this required difference of speed can also be
produced by mechanical friction applied to one of them.
The two motors may if convenient be originally constructed of different power.
In witness whereof I the said Frank Wynne have hereunto set my hand and
seal this 15th day of November A.D. 1883.
TD TTZ
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