Year: 1899

page_text: A communication by LOUIS LÉON HECTOR GERARD, of 16, Rue des Grandes,
Carrières, Paris, in the Republic of France, Mechanical Engineer.
I, GEORGE CECIL DYMOND, M.Inst.M.E., of the Agency for Foreign Patent Soli-
citors, 6, Lord Street, Liverpool, and 6, Bank Street, Manchester, both in the
County of Lancaster, 118, New Street, Birmingham, in the County of Warwick,
and 322, High Holborn, in the County of Middlesex, Patent Agent, do hereby
declare the nature of this invention to be as follows:-
This invention relates to improved systems of gearing by epicycloidal trains
enabling changes of speed to be obtained under very favourable conditions,
that is to say avoiding the sudden shocks which are produced by means of the
systems at present employed for changing speed in cycles, motor cycles, auto-
cars and other like vehicles. But it must be understood that the invention can
also be applied to the changing of speeds in any kind of apparatuses or machines
where it may be found useful to employ it.
The invention consists essentially in transmitting the movement of a given
shaft having a continuous rotary motion to a second shaft parallel to the first
by means of a train of epicycloidal gearing having a progressive action, the
combination of several arrangements of the kind constituting a speed changing
apparatus.
A pinion keyed on a motor shaft and a loose gearing formed of a ring with
internal teeth are mounted on a motor shaft having a continuous rotary motion.
Between these gearings there is a loose epicycloidal pinion, the axle of which
is firmly connected with a toothed wheel loosely mounted on the motor shaft
and gearing constantly with a toothed wheel keyed on the shaft which is to be
driven. The apparatus being thus formed, and as the shaft to be driven opposes
a certain resistance by the intermediary of gearing loosely mounted on the motor
shaft to the planet movement of the epicycloidal satellite pinion, the latter is
caused to revolve on its axis and communicates to the ring with internal teeth
a rotary movement in a contrary direction to that of the motor pinion. If it be
now supposed that the wheel with the internal teeth be rendered stationary by
any suitable means for instance by means of a cord brake, the resistance which
prevented the rotation of the driving wheel might be overcome, the satellite
pinion would then be forced to travel round or on the internal teeth of the satel-
lite gearing and would carry with it the driving shaft by the intermediary of
the interposed gearings.
Taking into account the angular speed of rotation thus communicated to the
axis of the satellite pinion travelling round the motor shaft and consequently
to the toothed wheel which carries said pinion, it will be found that this angular
speed depends on the respective number of the teeth of the internal toothed
ring and on the number of teeth of the external toothed ring or pinion keyed
on the motor shaft, If the angular speed of the motor shaft be indicated by Va

page_text: It will now be explained how the apparatus is obtained for changing speed
which forms the object of this invention by combining with one another two or
more gearings having epicycloidal trains. Three examples of these combinations
will now be described:-
In the first arrangement the motor shaft has two fixed pinions of different
diameters each arranged in the interior of a concentric gearing having internal
teeth loosely mounted on said shaft preferably by means of a ball bearing or in
other suitable manner.
The motor shaft has further between the two pinions a sleeve loosely mounted
on said shaft on which sleeve there are keyed the pinion, which actuates the
wheel keyed on the shaft to be operated with a variable speed according to the
gearing in engagement as will be hereinafter explained, and also two discs each
carrying one or more pinions loosely mounted on their axes gearing simul-
taneously with the pinion keyed on the driving shaft and the internal toothed
rings. The latter are each provided with, a circular groove in which a brake
cord is lodged. If the motor shaft be in movement and one of the rings be ren-
dered stationary by pulling the cord of the brake, the satellite pinion carried
round by the motor pinion will be forced to travel on the ring and will thus
carry with it the disc and consequently the loose pinion which is connected
therewith. According to what has been hereinbefore explained, it is evident
that if be taken to be the angular speed of rotation transmitted to this pinion,
Va the angular speed of the motor shaft, b and d the number of teeth respec-
tively of the motor pinion and the internal toothed gearing we obtain :
One of these two gearings may be replaced by an arrangement for back-
ward travelling formed in the same way with the difference that the external
toothed ring is connected with the plate carrying the pinion which gears with
the driving gear, and that the satellite pinions are mounted on another plate
which is loose on the driving shaft but capable of being rendered stationary by
means of a band brake placed over a suitable groove.
In the second example, fixed pinions are juxtaposed on the motor shaft and
the two satellite pinions are mounted on the same axis. The internal toothed
gearings are reduced to simple rings held freely between two discs connected by
means of cross pieces and bearing the axes of the satellite pinions. The gearings
are each provided laterally with two free rings mounted in grooves of the cor-
responding gearing and the diameter of which is exactly equal to that of the
primitive circumference or periphery of the gearing. In this way the rings
travel without sliding one on the other and support and maintain in place the
toothed rings.
An identical apparatus may be arranged symmetrically as regards the driving
pinion in order to form an apparatus having four speeds, and the corresponding
brake bands may then be actuated by means of a common arrangement consist-

page_text: ing of a shaft four times bent caused to revolve by means of any suitable operat-
ing arrangement. It is evident of course (and this will constitute the third ex-
ample mentioned) that instead of placing two pairs of gearings on each side of
the driving wheel as many gearings as may be desired may be placed end to
end, each of said gearings corresponding to a different speed.
A communication by LOUIS LÉON HECTOR GERARD, of 16, Rue des Grandes
Carrières, Paris, in the Republic of France, Mechanical Engineer.
I, GEORGE CECIL DYMOND, M. Inst. M.E., of the Agency for Foreign Patent Soli-
citors, 6. Lord Street, Liverpool, and (i, Bank Street, Manchester, both in the
County of Lancaster, 118, New Street, Birmingham, in the County of Warwick,
and 322, High Holborn, in the County of Middlesex, Patent Agent, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:
This invention relates to improved systems of gearing by epicycloidal trains
enabling changes of speed to be obtained under very favourable conditions,
that is to say avoiding the sudden shocks which are produced in most of the
systems at present employed for changing speed in cycles, motor cycles, auto-
cars and other like vehicles. But it must be understood that the invention can
also be applied to the changing of speeds in any kind of apparatuses or machines
where it may be found useful to employ it.
The invention consists essentially in transmitting the movement of a given
shaft having a continuous rotary motion to a second shaft parallel to the first
by means of a train of epicycloidal gearing having a progressive action, the
combination of several arrangements of the kind constituting a speed changing
apparatus.
In the accompanying drawings,
Figure 1 is a section of a system of gearing having two speeds;
Figure 2 is a section of a system of gearing for several speeds in which the
gearings are arranged in succession one to the other.
In the arrangement shown in Figure 1, the motor shaft A has two fixed
pinions B and B of different diameters each arranged in the interior of a
concentric gearing D D having internal teeth loosely mounted on said shaft
preferably by means of a ball bearing P or in other suitable manner.
The motor shaft A has further between the two pinions B, B', a sleeve M
loosely mounted on said shaft on which sleeve there are keyed a pinion E, which
actuates a wheel F keyed on the shaft L to be operated with a variable speed
according to the gearing in engagement as will be hereinafter explained, and
also two discs H and H' each carrying one or more pinions C, C¹, loosely mounted
on their axes h, h¹. The internally toothed rings D D are each provided with
a peripheral groove in which a brake cord f and f¹ is lodged. If the motor
shaft A be in movement and one of the rings 1) be rendered stationary by pull-
ing the cord f of the brake, the planet pinion C carried round by the motor
pinion B will be forced to travel on the ring D and will thus carry with it the

page_text: disc H and consequently the loose pinion E which is connected therewith. Accord-
ing to what has been herein before explained, it is evident that if V be taken to
be the angular speed of rotation thus transmitted to this pinion E, Va the angular
speed of the motor shaft A, b and d the number of teeth respectively of the motor
pinion B and the internal toothed gearing 1), we obtain
One of these two gearings may be replaced by an arrangement for backward
travelling formed in the same way with the difference that the internal toothed
ring is connected with the disc H, and that the planet pinions C are mounted
on another disc D which is loose on the driving shaft A but capable of being
rendered stationary by means of a band brake placed over a suitable groove.
This arrangement is not shown in the drawings.
The arrangement herein before described explains how an apparatus for chang-
ing speed by epicycloidal trains may be constructed but this arrangement only
allows of two changes of speed.
In order to arrange in succession any suitable number of apparatuses for
changing speed the feature shown in Figure 2 is employed which forms an
apparatus having four speeds.
Four fixed pinions B B1 B2 and B³ are mounted on the same motor shaft A
side by side and they gear with planet pinions C C C C mounted loosely on a
common shaft h. The internal toothed gearings D D1 D2 D3 are reduced to
simple rings held freely between the discs H and I which are connected by cross
bars and carry the axes h of the planet pinions. The disc H for instance loosely
mounted on the shaft A is prolonged by a sleeve carrying a pinion E which
transmits the movement to a toothed wheel F. Gear wheels B B1 B2 B3, satellite
pinions C C C C³, toothed rings D D1 D2 133, are each provided laterally with
free rings bb1 62 6³, c c¹ c² c³ and d d¹² d³ respectively. These rings are located
in grooves in the corresponding gearing and they may if desired be fixed to the
said gearing by screws or other suitable means of attachment. The external
diameter of these rings is exactly equal to that of the primitive circumference
of the gearings in such a way that said rings travel without slipping one on the
other and maintain the toothed rings D D D2 D3 in place. In order to render
the latter stationary they are provided externally with grooves which receive
brake bands f f f f which may be actuated individually by a four times bent
shaft Kas shown in the drawings or in any other suitable manner. In the
drawings a single series of satellite pinions C C1 C2 C3 are shown mounted on the
same shaft but of course in practice three, four or more sets of pinions may be
employed. In the same way an arrangement for speeds is shown but this
number may be increased or diminished in this arrangement as desired.
Having now particularly described and ascertained the nature of the said in-
vention and in what manner the same is to be performed, as communicated to
me by my foreign correspondent, I declare that what I claim is;-
1. A variable speed gearing in which each different speed is obtained by an
epicycloidal train which comprises pinions such as B1 B2 B3 keyed on the
driving shaft A, internally toothed wheels D D1 D2 D3 loosely mounted on said
shaft. provided with an arrangement enabling them to be prevented turning at
any desired moment, and one or more planet pinions firmly mounted on a com-

page_text: mon transmitting gear such as E in such a way that when one of the toothed
wheels D is rendered stationary, the movement of the shaft A is transmitted
to the pinion D by the corresponding epicycloidal train, the speed of rotation
thus transmitted to the wheel È being dependent on the number of teeth of the
gearings B D, Figure 1, showing an application of this arrangement to an ap-
paratus having two speeds, in which the pinion E is provided laterally with
two discs H H¹ carrying the axes of planet pinions C C, whilst the internally
toothed wheels D D loosely mounted on the shaft A may be rendered stationary
at a desired moment by a cord brake, substantially as herein before set forth.
2. The form of construction for change of speed by means of epicycloidal trains,
characterised by the use of planet pinions mounted side by side on a common
shaft and of progressive diameters, and gearing respectively on the one hand
with fixed pinions keyed on the motor shaft, and on the other hand with inter-
nally toothed wheels having exactly the same centre as the fixed pinions, and
adapted to be rendered stationary respectively by means of corresponding brake
bands, the common shaft of the planet pinions being mounted on two dises or
cranks loose on the motor shaft, and connected with the shaft for transmitting
the movement, the said toothed wheels, planet pinions, and fixed pinions being
provided with cylindrical rings the external diameter of which is equal to that
of the primitive circumferences of the corresponding gearings, which whether
fixed or otherwise to the said gearings, travel one upon the other, and maintain
them exactly centred and at the desired distance, substantially as herein before
described and shown in the accompanying drawings.
Dated this 19th day of October 1900