Improvements in Speed Changing and Reversing Mechanism.
Year: 1898

page_text: -
Improvements in Speed Changing and Reversing Mechanism.
I, EUGENE RAVASSE, of 99, Rue de Crimee, Paris, in the Republic of France,
Mechanical Engineer, 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 speed and reversing mechanism, characterised essentially
by the arrangement of two plates, the axes of which are not in line with one another,
and one of which carries a crown wheel with internal teeth, while the other carries
several trains of gear wheels, worked by the shaft forming the axis of the second
plate, in such a manner that if this last plate is turned on its axis, the trains of gear
wheels, without ceasing to be controlled by the said shaft, become successively
engaged with the teeth of the crown wheel, the other trains at the same tine being
out of engagement.
This arrangement has the advantage of occupying a very limited space and of
effecting the various alterations of speed or of direction without shock.
In the accompanying drawing,
Figure 1 is a sectional elevation of the mechanism;
Figure 2 is a transverse section taken on the plane of the two axes; and,
Figure 3 is a view of the plate carrying the trains of gear wheels;
A is the driving shaft; B a toothed wheel formed on or attached to this shaft ; C
is a pinion fixed to the said driving shaft A; D is the plate carrying the various
trains of gear wheels.
A1, A2, A3, B³, C3, D3, A4, B4, C4 are the wheels and pinions constituting the various
trains of gear wheels; which are loose on their respective axes.
The wheels A and B are formed in one piece as are also the wheel A and B*.
The wheels A¹, A³, C³, D³, and C are simply intermediate ones and do not
affect the ratio of the speeds but serve only to transmit the movement from the
shaft A to the shaft G.
E is the crown wheel with internal teeth, fixed on the inside face of a plate F,
which itself is fixed to the shaft G.
H is an endless screw or worm operating a worm wheel I which is fastened on the
plate D, and intended to give motion to it, for the purpose of producing variations
of speed.
The shafts A and G are suitably iournalled in fixed bearings J and K.

page_text: When the plates D and F are in the relative positions shown in the drawing, the
parts in gear will be A, A¹ and E and the ratio of speed will be
20
96
C 20
==== 96
the speed of the shaft G will be of the speed of the shaft A.
In this case
If the endless screw or worm H is turned so as to rotate the plate D in the direction
of the motion of the shaft A, the wheel A¹, by degrees becomes disengaged from the
toothed crown wheel E, whilst the wheel A² approaches it and becomes engaged with
it as soon as the pinion A¹ becomes disengaged therefrom. When the screw or worm
has turned the plate D through a quarter of a turn the pinion A² will occupy the
position of the pinion A¹.
The ratio of the speeds is then :
B 12
Q6'
In this case the speed of the shaft G
When the plates D and F are in the relative positions shown in the drawing, the
parts in gear will be A, A¹ and E and the ratio of speed will be
C
20
=
In this case
96
the speed of the shaft G will be
of the speed of the shaft A.
20
96
If the endless screw or worm H is turned so as to rotate the plate D in the direction
of the motion of the shaft A, the wheel A¹, by degrees becomes disengaged from the
toothed crown wheel E, whilst the wheel A² approaches it and becomes engaged with
it as soon as the pinion A¹ becomes disengaged therefrom. When the screw or worm
has turned the plate D through a quarter of a turn the pinion A² will occupy the
position of the pinion A¹.
The ratio of the speeds is then :
12
will be the speed of the shaft A.
96
B 12
T
In this case the speed of the shaft G
If the endless screw or worm is turned in the same direction so as to impart to the
plate D another quarter turn, the pinion D³ will replace the wheel A². The ratio
of the speed then becomes :-
which is the same as before, but in consequence of using only one intermediary
pinion, C, instead of two pinions C³ and D³, the direction of the rotation is
changed.
I thus obtain with this mechanism three variations of speed and a reversal of
direction.
It is evident that the ratios of the speeds of the shafts A and G may be modified,
and that it is likewise easy, by inodifying the dimensions of the plates in which the
shafts are eccentrically arranged to obtain a greater number of variations.
My speed changing and reversing mechanism, the size of which is very limited,
and which enables the various changes of speed and direction to be effected, is
applicable with particular advantage to motor-carriages. It needs simply to be
arranged below the vehicle, one part connected with the driving shaft and the other,
through a suitable transmitter, with a hand wheel, by means of which the driver
effects the changes of speed and direction, in the manner described. The said
mechanism is not however limited to motor carriages, but may also be applied to
machine-tools and the like.
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. The means for altering the speed and direction of motion of any shaft, by the
ise of a system of two plates, the axes of which are not in the same line, and one
of these plates carrying a crown wheel with internal teeth, whilst the other carries
several trains of gear-wheels, worked by the shaft lying in the axis of this second
plate, in such a manner that if this last plate is turned on its axis, the trains of gear
'

page_text: wheels, without ceasing to be controlled by the shaft, will successively engage with
internal teeth of the crown wheel, the other trains not engaging.
2. The mechanism above described with reference to Figures 1, 2 and 3 of the
accompanying drawing, for changing speed and direction, and its application to
motor carriages and vehicles, machine-tools and the like.
3. The special application of this mechanism to a motor-carriage, this mechanism,
placed under the vehicle and connected with the driving-shaft, being easily worked
by a 'hand wheel, substantially as described.
4. The mechanism for changing speed and direction, in principle as above
described, the dimensions and arrangement of the constituent parts being adapted
to be varied so as to give any number of variations of speed, according to the various
uses to which it may be applied.
Dated this 26th day of February 1898.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.