Improvements in and relating to Speed and Reversing Gear for Motor Carriages and other purposes.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improvements in and relating to Speed and Reversing Gear for
Motor Carriages and other purposes.
I, VICTOR ETIENNE PRÉTOT, of 21 Boulevard Poissonierè Paris, in the Republic
of France, Mechanician, do hereby declare the nature of this invention to be as
follows:-
common
This mechanism is based upon the principle of the union, upon a
shaft, of several sets of planetary differential gear wheels, comprising each a fixed
wheel, or a wheel which can be rendered immovable, and a wheel keyed upon the
shaft or part to be operated or adapted to be firmly connected therewith, these two
concentric wheels set in connection by one or more groups of satellite pinions
respectively connected with one another and appertaining to a disc or crown receiving
from the motor a movement of a given speed which it transmits, modified in the
proportion resulting from the action of the gear wheels, to the shaft or part which
is operated.
The sets thus grouped being naturally combined for obtaining different propor-
tions it is evident that, according as one or the other is set in operation, the driven
part will receive a movement of different speed, that of the motor being supposed to
be constant, but if moreover one or more of the sets comprise for instance the driven
central wheel smaller than the fixed central wheel, whilst for the others the inverse
is the case, the movement transmitted by them will take place in the opposite
direction to that which is effected by those in the other case, hence the possibility of
obtaining not only a change of speed but also the reversal of the motion.
As regards the principal use to which this mechanism is applied, that is to say,
motor carriages, its principle even realizes an important improvement. In fact it is
well known that in this case the necessity for reducing the weight and volume of the
motor helps to give it a greater speed necessitating consequently a considerable
reduction to be transmitted to the wheels.
From this follows almost always the need for employing at least two intermediate
shafts and gear wheels of a large diameter. On the contrary the planetary
differential movement enables me to obtain if necessary large proportions with
comparatively small gear wheels, hence a considerable saving of obstruction and
greater compactness.
The limits within which my system enables me to vary the speed are further
increased by the adjunction of a device which, while using one or the other of the
sets, permits of the variation of the speed of the motor in a certain proportion:
the number of different speeds which I have at disposal is therefore in reality double
or multiple of that of the sets.
The invention is completed by the means employed for operating the whole of the
mechanism and set in action that of the sets corresponding to the speed or to the
direction of motion required. In any intermediate position the apparatus is
disengaged and the driven part receives no movement.
In the accompanying drawing this mechanism is represented.

page_text: The initial movement is received by disc or wheel A which may be secured directly
upon the shaft of the motor or form a pulley or toothed crown in order to be actuated
by the same with a first and constant reduction of the speed. The driven receiving
part is here a chain pinion B which can transmit the movement directly to the
toothed crown of the differential gear mounted in the axle: the pinion B turns
loosely upon the shaft b upon which the disc A is keyed. The contrary may be the
case if this disc receives the movement by its circumference as represented.
In this example the pinion B is connected with a single central gear wheel C
operated by the corresponding pinion or pinions Dappertaining to the satellite shafts a
(I have hereinbefore stated that there may be one or more of these shafts, the whole
requiring in any case to be balanced) whilst the first engagement, comprising the
other planetary pinion E F G¹ or H' and the central wheel E, F, G or H having to
remain fixed, is repeated according to the different proportions answering in this case
to three speed for the normal forward movement and a single speed for the backward
movement.
Without changing the principle of the system this arrangement may be different,
that is to say, it may on the contrary have several couples of driven wheels, for
example such as CD and a single couple of driving wheels E E' or several of both, of
course taking into consideration that at a time one of the central wheels of the first
engagement is connected with the driven part and that only one of the central wheels
of the second is kept immovable.
Accordingly the operation of the mechanism is in short as follows: the wheel F
for example (Figure 1) being kept immovable, if the disc A is set in rotary movement,
carrying with it the shafts, the pinion F rolling upon the wheel F will turn the
shaft a and consequently the pinion D which will give to the wheel C a movement
resulting from the difference between the number of teeth of the wheels on the same
shaft of course if the pinions F¹ D were equal, and in like manner therefore the
wheels FC, the latter wheel would not receive any movement. It will also be seen
that if the fixed wheel F is larger than the driven wheel C as in Figure 1, the latter
will receive a movement in the opposite direction to that of the disc A, whereas it will
be in the same direction if the movement bears upon wheel H rendered immovable
for this purpose (see the diagram to a reduced scale in Figure 6). In the case
represented the gear wheels H H must be set in action for the backward novement,
whilst the gear wheels E E¹, F F or G G¹ correspond to the forward movement at
different speeds.
When none of the wheels E F G H is rendered immovable the wheel C which,
being held by the resistance of the vehicle, plays the part of a fixed wheel, whilst
the other gear wheels turn loosely one upon the other or upon the shaft b of the
disc A.
The relative movements of these various parts may be effected either by surfaces
of such a nature that little friction will be caused, on well lubricated surfaces, or by
ball bearings. Each of the wheels E F G H which must be rendered immovable in
ita turn appertains to a sleeve (concentric to those of the other gear wheels and to the
shaft b) connected with a dise I whose periphery, of suitable outline or presenting
one or more stop notches, may be set in connection with a collar, chain, block or
serew I at will, designed to prevent it from turning and also the gear wheel with
which it is connected.
These discs I may be made in two parts, one of which is central and the other
surrounds it exteriorly, these two parts being connected by one or more ratchet
devices so that when in the course of a descent the vehicle is allowed to move by its
own impulsion, the driving mechanism may not receive from the wheels a motion of
too great a speed.
The stop parts I are under the action of cams c, of which it is then sufficient to
turn the shaft d through a suitable angle for acting upon the stop part of the disc
corresponding to one of the wheels E F G or H to obtain the speed or the direction
of the movement. As two of these discs cannot in any case be rendered immovable
together there is between the positions corresponding to the stoppage of each of them

page_text: a dead point where the mechanism is entirely free and where no movement whatever
is transmitted to the driven part B; this is the uncoupled position.
But each cam c presents in its major radius a certain width within which the
immovableness of the corresponding disc is kept, and the shaft d of these cams
carries a star e presenting rather deep cavities separated by simple stop notches which
are not very accentuated: the key f with which this star is in connection acts upon
the device for regulating the speed of the motor in such a manner that if, without
passing for this purpose from one set of gear wheels to another, I cause the shaft d
to turn through a distance small enough for the cam in action not to release the dise
rendered immovable but sufficient for passing from one notch of the star to another
which is deeper or not so deep, the speed of the motor will undergo a corresponding
modification. If lastly it is useful to keep the motor in motion during short stoppages
but at a very small speed in order to obviate at the same time the noise, the vibration
and a useless expenditure, I bring the shaft d to such a position that the key f will
come opposite a notch g much deeper than any of the others, by reason of which the
movement of the motor will be regulated so that it will turn only at the speed
merely sufficient for keeping up its movement until the vehicle starts again.
The operation of this shaft d is obtained by the pinion h which it carries and a
rack h¹ connected to a lever placed within reach of the driver, with ineans for fixing
it in each position required.
If this mechanism is applied to a motor acting upon the driving wheels the
transmission of this driving gear is effected by means of levers having a fork engaging
with one or more sleeves connected therewith and displaced in the axis of the pivot
bolt. The steering movement of the fore-carriage is effected through the medium
of four or more rollers enabling me to give to this contact the necessary precision for
the transmission of the aforesaid movements with the minimum of friction.
I reserve any applications of this system and particularly to motor carriages of any
kind, for which it possesses moreover the advantage of occupying a smaller space than
the arrangements in use.
I reserve the right to make in my invention any modifications as regards
dimensions or details of construction without changing the principle underlying the
same.
Improvements in and relating to Speed and Reversing Gear for
Motor Carriages and other purposes.
I, VICTOR ETIENNE PRÉTOT, of 21 Boulevard Poissonierè Paris, in the Republic of
France, Méchanician, 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 :-
This invention relates to improvements in variable speed and reversing gear which
is so constructed as to render the same as compact and light as possible, whereby the
said gear will be especially suitable for use in motor cars.
The main features of my invention stated shortly are:-
To group several differential planetary gearings upon a single shaft ;
To so actuate each of these gearings that one or the other may be set in operation
at will for the purpose for varying the speed; and

page_text: To so arrange these gearings relatively to each other that the transmission of the
motion will be either direct or reversed.
The invention, moreover, comprises various constructional details and arrange-
ments which are hereinafter referred to.
In order that my invention may be clearly understood and readily carried into
effect I will proceed to fully describe the same with reference to the accompanying
drawing, in which:
Figure represents a front elevation of my improved gear;
Figure 2 is a vertical section on the line 2-2 of Figure 1;
Figures 3, 4 and 5 represent constructional details;
Figure 6 represents an explanatory diagram of the transmission gear as specially
designed for the reversal of motion;
Figures 7 and 8 refer to a modified form of one of the constituent parts of the
improved apparatus;
Referring more particularly to Figures 1 and 2, A is the driving wheel consisting
of a toothed wheel or a disc keyed on a shaft b. The said driving wheel may be
revolved either by the shaft, on which it is mounted, or by a toothed pinion gearing
with the teeth formed on its periphery. C is the driven wheel consisting of a
toothed pinion loosely mounted upon the said shaft b and receiving the movement
after its transformation by the gear. This pinion may be connected to or be formed
with a chain wheel B or similar device by which the transformed movement is trans-
mitted to another chain wheel or similar device that has to be driven. E, F, G, H,
are several toothed wheels respectively connected to discs I, I, I, I, through the
medium of their hubs which loosely fit into one another, the wheel H being also
loosely mounted on the shaft b. The said driving wheel A carries one or several
groups of satellite-pinions each group comprising as many pinions E F G H' as
there are wheels E F G H, with which they respectively gear. D, D, D, D, are
pinions gearing with the toothed pinion C, each pinion D being connected with one
of the aforesaid groups of satellite-pinions.
Each group of satellite pinions E F G H is keyed on a spindle a freely rotating
in a boss provided for this purpose on the driving wheel A. The pinions D are also
keyed or otherwise connected to the spindles a.
From this arrangement it will be evident that one of the wheels E, F, G, H, one
of the pinions E, F, G, H, of the different groups of satellite-pinions the driving
wheel A, one of the pinions, D, D, D, D, and the pinion C constitutes a differential gear
mechanism. It is also evident that the driving wheel A and the pinion Care
common to all the constituent gears, the number of which may of course vary, owing
to the method of fitting the hubs of the wheels E, F, G, H, concentrically one into
another.
The relative diameters of the wheels E, F, G, H, and of the pinions E F G H¹ is
optional; so long as the diameter of one of the wheels (for instance the wheel H)
is less than that of the pinion C.
The dises I, I, I, I, respectively connected to the wheels E, F, G, H, are each
provided with a peripheral groove for the reception of a flexible band or collar 1 one
of the ends of which is fastened to a rocking arm i mounted freely upon a shaft o and
the other to a lever freely pivotting upon the said shaft. Arranged parallel to this
shaft o is another shaft d, provided with as many projections or tappets c as there are
arm's i, the said projections being arranged around the shaft d in different angular
positions (see Figure 3) in such a manner as to allow of their successive action upon
their corresponding arm i. A pinion h (Figure 3) is keyed on the shaft d and gears
with a rack bar, h¹ (Figure 4) which can be actuated in a rectilinear direction by the
aid of an operating rod or in any other appropriate manner, so as to turn the pinion h
and consequently the shaft d, in order that the latter may bring one or the other of
its tappets or projections in contact with the corresponding arin
I will now proceed to describe the operation of the gear :-
Let it be supposed that the driving wheel A is revolving and that the shaft d has
been turned to cause one of the arms i to rock and thereby cause the corresponding

page_text: band I to grip the disc I and so stop the revolution thereof as well as that of the
corresponding wheel E, F, G, or H. Let it be supposed that the wheel F is the one
that has been so stopped.
Then as the groups of satellite-pinions E, F, G, H are carried around the shaft b
by the wheel A, the pinion F¹ in each of these groups, that is to say the pinion that
corresponds to the stopper wheel F, revolves on its axis together with its spindle a
and thus also revolves the wheel D, which in turn transmits its movement to the
pinion C and chain wheel B.
During this operation the other pinions E, G, H act upon their respective
wheels E G H which being at this time unrestrained revolve loosely on the shaft b
without effecting any change in speed.
It is therefore evident that if another wheel than F1, for instance the wheel E or G
be stopped by gripping the corresponding disc with its brake band I', different.
relative sets of the gearing will be set in motion and that, consequently, the speed
will be changed. These changes of speed which are capable of almost endless.
variation, are obtained by an extremely compact device, while at the same time the
said changes are effected without concussion inasmuch as the mechanism by which
the motion is transmitted to the vehicle is always in gear, and the changes are
obtained by applying a brake, consisting of a grooved dise and a band or collar, as
has been specified.
When the wheel H (which is less in diameter than that of the driven pinion C) is
stopped the rotary motion is transmitted in the reverse direction. This reversal of
motion is due to the fact that the point of contact x (Figures 1 and 6) of the
corresponding satellite-pinion H', with the wheel H lies upon a smaller radius than
that of the pinion C (see the diagraminatic view Figure 6) whereas with regard to
the other satellite-pinions the said point of contact is situated upon a larger radius
than that of the said pinion C (see Figure 1). The reversal of the rotary movement
thus results from the fact that the wheel H is smaller than the pinion C.
When none of the wheels E, F, G, H is stopped, then the pinion C, held in
position for instance by the resistance of the vehicle, plays the part of a fixed wheel
whilst the other gearings turn loosely upon one another, or upon the shaft b.
The said brake-bands or collars I1, may be arranged and actuated in the manner
indicated in Figures 7 and 8. In this case they completely surround their
respective discs and revolve therewith until a resistance counteracts such revolution.
Their ends are flanged and connected by a bolt and one of such flanged ends, being
longer than the other, forms a heel or projection I which, at the required times is
enabled to abut against a catch I on a lever I oscillating upon the shaft o like the
arm i above referred to. The number of the levers I employed is in accordance
with the number of the brake-bands or collars and such levers I are set in action at
will by the tappets or projections c of the shaft d above referred to. The braking of
the disc corresponding to the wheel to be stopped, is effected by the stopping of the
heel or projection I by the lever I actuated by turning the shaft d. The aforesaid
catches are pivotally connected to the levers I and are each provided with a
spring I (Figure 7) so that in the event of the brake band or collar turning in the
reverse direction, the said catches I will give way to the heels or projections I* and
allow the brake band or collar to turn with its disc, in spite of the lever I occupying
the braking position. The reverse rotation of the respective brake bands or collars
results when the vehicle travels down an incline and has a tendency to increase its
velocity and drive the mechanism at a higher speed than that intended or stipulated.
Owing to the spring catches above referred to, the movements of the driving wheel A
and of the driven pinion C remain absolutely independent under these circumstances
and when the speed of the vehicle tends to again become equal to or lower than, that
imparted to it by the motor, then the disc I and its band or collar I' (corresponding
to the initial speed) first resume the state of rest and then commence moving in a
direction for the heel I to be stopped by lever I', whereby the vehicle is again placed
under the control of the motor.
If, contrary to the case indicated in Figure 2, the driving wheel A is loosely

page_text: mounted upon the shaft E, whilst the pinions C and B'are rigidly connected there-
with, another dise J (Figure 8) may then be fixed. upon the said shaft b, such disc
'receiving the bands or collars J' each acting in conjunction with a lever similar to I
and actuated in an analogous manner. This disc J and the parts connected therewith
constitute a gradually acting brake, operated by the same means as the change of
speed and the reversal of motion. Therefore by continuing one and the same opera-
tion the driver is enabled to pass from the state of slow speed to that of disengagement
and subsequently to that of braking, for the purpose of either simply reducing the
speed (if only one of the bands or collars J be engaged) or of stopping entirely if
both of the bands J' be operated; on further continuing, the brakes are released and
lastly motion is re-contenced when required. In order to render the action of
these brakes more rapid and to avoid waiting. until the disc has nearly completed
another revolution, the bands J are each provided with two heels 1 arranged
diametrically opposite.
Another part of my invention has for its object to vary the limits of speed obtained
by the improved gear. For this purpose I employ a device, by which the regulating
mechanism of the motor can be acted upon without, for the moment, interfering
with the action of the gear. This device consists of what I may term a star piece e
(Figures 3 and 5) keyed upon the said shaft d and so formed as to give a rectilinear
movement to a frame when the star piece is turned. For this purpose its edge
may have depressions or recesses separated by stop-notches.
The aforesaid frame f surrounds the star piece and has an inwardly projecting
tooth which is held in constant contact with the star piece by a spring or other
suitable means. The frame with its tooth f is connected to the part or mechanism
which regulates the speed of the motor, in any suitable níanner. Its displacements,
under the influence of the star piece e acting upon the tooth f, are thus transmitted
to the said regulating member or mechanism. Moreover the working faces of the
aforesaid tappets or projections c (Figures 1 and 7) are concentrically formed with
respect to the shaft d so that during a portion of the angular movement of said
shaft, depending on the extent of the concentric working faces of the projections c,
the latter do not affect the position of the arms i or lever I2. The star piece e is so
keyed upon the shaft d relatively to the tappets or projections e, that during the
time of the inactive angular movement above referred to, the tooth f passes from a
depression or recess to a projection, with the result as herein before stated, that the
speed of the motor is varied and consequently the changes of speed obtained by the
gearing mechanisms are considerably augmented.
The said star piece e may have one depression g deeper than the others and will
then serve to still more decrease the speed of the motor, which will be found useful
when the vehicle is to stand still for some time.
Having now particularly described and ascertained the nature of my said
invention and in what manner, the same is to be performed, I declare that what I
claim is :-
1. A variable speed gear comprising a disc or wheel carrying on one side a
group or groups of unequal planet pinions each group being rigidly connected to the
same axis and revolving around and in gear with an equal number of concentrically
disposed toothed wheels loosely mounted and revolving independently of one another
on the axis of the disc, a pinion on the other side of the disc keyed to the axis of each
group of planet pinions and revolving around and in gear with a pinion loosely
mounted on the axis of the disc, and means substantially as described whereby any
of the said concentrically disposed toothed wheels can be held stationary for the
purpose specified.
2. In speed gear of the kind claimed 'above, the combination of a driving wheel A
mounted upon a shaft b and susceptible of receiving rotation from its centre or from
its periphery of a driven pinion C arranged loosely upon the said shaft b; of a
number of differential wheels E, F, G. . . . arranged loosely upon the shaft b and
being of a larger diameter than that of the: driven pinion C; of dises III...

page_text: respectively connected to or integral with the said wheels E F G. . . and capable of
being stopped by brake bands or collars I, I, I¹. . . . ; of one or several groups
of differential satellite-pinions E, F, G¹. . . . gearing with the differential wheel; of
one or several pinions D connected to or rigid with the groups of satellite pinions and
gearing with the driven pinion C; the whole device arranged and operating in the
inanuer described and for the purpose specified.
3. The combination with the speed gear claimed in the first and second claims, of
a supplementary planetary gearing mechanism comprising a wheel H of less diameter
than the driven pinion C and provided with a brake disc I, and of a pinion H¹
forming part of each group of satellite pinions and gearing with the said wheel H the
said combination serving on the one hand for obtaining the variations of speed and
on the other hand for reversing the motion, substantially as specified.
4. For the purpose of stopping one or the other of the wheels E, F, G, H... in
order to vary the speed or to reverse the motion, the rotary shaft d provided with
tappets or projections c so arranged that by the angular movement of said shaft one
or the other of the brake-bands I can be caused to grip its disc I substantially as
described.
5. The arrangement of the brake-bands to completely surround the respective disc I,
and their construction with a heel or projection I* to be acted upon by levers I which
are provided with spring catches or stops Is and which are brought into operation by
tappets or projections c on the rotary shaft d, substantially as described.
6. The combination with the aforesaid tappets or projections c on the rotary
shaft d, of a star piece e acting in conjunction with a tooth f on a movable frame f¹
connected with the regulating part or mechanism of the motor substantially as
described and for the purpose specified.
Dated this 24th day of July 1897
HASELTINE, LAKE & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.