Power Transmitting Mechanism.
Year: 1899

page_text: Date of Application, 20th June, 1899-Accepted, 30th Sept., 1899
Power Transmitting Mechanism.
"I, GEORGE BELL BIRRELL, Inventor, a citizen of the United States, of 253,
Broadway, in the City, County and State of New York, U.S.A., 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:-
The object of my invention is to provide a mechanism for transmitting power and
motion from a prime mover, such as the driving shaft of an electric-motor, to a
secondary or final mover, such as a car axle, hoisting drum, or any machine, which
mechanism may be adapted while the prime mover is moving continuously in one
direction and at a uniform speed to drive the secondary or final mover therefrom
either in the same or opposite direction, or at any desired relative speed in the same
or in the opposite direction, or to hold it stationary.
My invention consists essentially of a revoluble primary shaft, an eccentric: or
eccentrics fixed therein, a plurality of what I term fulcrum gear wheels concentric
with said shaft and revoluble independently thereof and of each other, means for
controlling the rotation of the fulcrum gear wheels independently of each other, a
secondary gear wheel concentric with the primary shaft and revoluble independently
thereof, and a plurality of eccentrically mounted and driven gear wheels rolling on
the respective fulerum gear wheels and having a gear rolling on the secondary gear
wheel, all as will be hereinafter fully described and claimed.
My invention also consists of means for controlling the rotation of the fulcrum
gear wheels and thereby the speed and direction of rotation of the secondary gear
wheel, which drives the secondary or final mover, from a single handle or operator,
as will be hereinafter fully described and claimed.
Reference is to be had by letters to the accompanying drawings forming part.of
this Specification in which-
Figure 1 is a longitudinal sectional elevation of a power-transmitting mechanism
embodying my invention, adapted for driving a secondary shaft in line with and from
the primary shaft at two different reduced speeds in the same direction as the
primary shaft, and in one reduced speed in a direction contrary to that of the
primary shaft.
Figure 2 is a cross sectional view of the same on the 22, Figure 1.
Figure 3 is a longitudinal sectional elevation of a power-transmitting mechanism
embodying my invention, adapted to drive a car axle (the secondary or final mover)
from a electro-motor shaft (the prime mover) at four different reduced speeds in the
same direction as the motor shaft, at two different reduced speeds in a direction
contrary to that of the motor shaft and to hold the car axle stationary while the
motor shaft is revolving, and provided with means for controlling the speed and
direction of motion of the car axle from a single handle or operator.
Referring first to Figures 1 and 2, A is the driving shaft or prime mover in line
with and concentric to the secondary or final mover or driven shaft B. C is a casing
having a base D and a lid or cover E, by means of which the casing may be made
both dust proof and oil tight. The shaft A carries an eccentric Fon which fits
loosely (without being keyed thereon) a wheel G. This wheel carries on one side an
external gear H and on the other side three gears, two internal I and J, and one

page_text: external K. The four gears on the wheel G are concentric with each other and with
the eccentric F. They are therefore eccentric to the centre of the shafts to the
extent of the throw of eccentric F.
Concentric with the shaft B and securely keyed or fastened thereon is a bushing
or sleeve L carrying an internal gear wheel M, the pitch diameter of which exceeds
the pitch diameter of gear H by twice the eccentricity of the eccentric F. It follows
that the gear M engages deepest with the gear H on the line running through the
centre of the shafts and the centre of the eccentric F and at the end of that line
nearest the eccentric, while at the other end of the line the two gears are withdrawn
from each other to the maximum extent. It follows also from the relative dimensions
of the gears H and M that as the prime mover A and the eccentric Fare revolved
the gear H will revolve tooth for tooth inside the gear M, and as the point of contact
rotates with the eccentric and as the numbers of teeth on the two gears are different
owing to the difference in the diameters the angular velocity must be different.
This relation of sizes between gears H and M applies to all the pairs of gears, one
eccentric to and the other concentric to the axis of shafts, which I use in mesh with
each other in my transmitter. I mean to say that in each and every such pair
or train of gears, regardless of the size of the gears, the pitch diameter of the
external gear exceeds that of the internal gear by twice the eccentricity of the
eccentric.
Meshing respectively with the two internal gears I and J and with the external
gear K on the wheel G are two external gears N and O and an internal gear P.
These gears are all three concentric to the shafts and are mounted respectively
on three fittings Q, R, S, which fittings terminate to the left in sleeves fitting over
one another, the inner one S fitting over the prime mover but not in any way secured
thereto; the outer fitting or sleeve Q revolves in a journal U formed on or secured to
the casing C and in the lid E there is another journal V in line with U, in which
revolves the sleeve L of the gear M, which as stated before is secured to the final
mover B. The sleeve ends of the fittings Q, R, S, project beyond the box or
journal U and in steps (as seen at Fig. 1) so as to adinit of each one having securely
fastened to it a band or brake wheel W, WI, W² It should be carefully noted that
each of the wheels or gears O, P, N, forms with its corresponding sleeve and brake
wheel one solidly connected body, each of these bodies being perfectly independent
of each other or of the motions of each other relatively to itself and independent also
of the shafts. By clamping any one of the brake wheels W, WI, W², it is evident
that the fitting and gear wheel to which it is attached will be prevented from
revolving and remain stationary and independently of the other gears.
X is a counterbalance weight permanently fastened on the shaft A to counterbalance
the eccentric F and disc G. The right hand end of shaft A is shown stepped or
journaled into shaft B to secure rigidity.
In Figures 3 I employ reference letters independent of Figures 1 and 2 to avoid
confusion. A¹ represents the car axle carrying the wheels B1, B¹ and trunnions C¹, C¹.
D is the armature of the motor permanently fastened on the hollow shaft or sleeve S
which is suitably journaled on the car axle A¹. E and E¹ are two casings united in
line with each other by the yokes F1, F which carry the field magnets G¹, G', of the
motor. The casings E and E¹ carry aligned journals H¹ and H', and also covers I¹
and I to make the casings both oil tight and dust proof. On the ends of the hollow
inotor shafts S are fixed eccentrics K₁ and K2 which are of the same throw, the same
diameter and the same face, and are set diametrically opposite each other. The
eccentric K carries a loose wheel L' having on one side gear M¹ meshing with a
gear O¹, the supporting wheel of which is fixed to the car axle. The eccentric K²
carries a loose wheel Pi having on one side a gear Q₁ meshing with a gear R¹, the
supporting wheel of which is permanently secured to the car axle A¹.
Both the secondary gear wheels 01 and R' are concentric to the shafts.
The wheel I carries on the side opposite gear M three gears (in this case two
.internal and one external) meshing respectively with three corresponding gears (two
external and one internal) concentric with the shafts. The supporting wheels S, T

page_text: U of these latter gears correspond with those shown in Fig. 1 at Q, R, S, and they
are likewise entirely independent of the driving shaft and of each other and are each
provided with a rigidly fastened brake wheel Vi, V2, V3, having shoes X1, X2, X³.
The wheel P¹ carries on the side opposite gear R₁ three gears (in this case one
external and two-internal) meshing respectively with three corresponding gears
concentric with the shaft and mounted on fittings a, b, c having solidly fastened
brake wheels d, e, f with brake shoes g, h, i.
There are also two brake wheels j and ; with shoes and k fastened rigidly on the
car axle.
1 represents a rheostat divided into seven sections six of which correspond
respectively with the brake wheels V1, V2, V3, f, e, d, so that the placing of the handle
of the rheostat in any one division will electrically tighten the shoe brakes of the
corresponding wheel and thereby lock the corresponding gear. The seventh division
which is not lettered corresponds with the two brake wheels ; and ; on the axle and
the placing of the handle on the said division will apply the brakes direct on the axle
which, none of the gears being locked, will receive no impulse from the motor shaft
although the latter will still be running at its full speed.
....
In this construction no counterbalance is needed. The eccentrics from their
location and construction described above balance each other so that by making the
wheels Land P¹ with the gears thereon, of equal weight-these wheels being of
symmetrical figure and therefore their centre of gravity at the centre of their
respective eccentrics-a perfect equipoise is provided for under all speeds and
.conditions.
:
It should also be noted that the construction shown is entirely supported by the
car axle and can therefore be made entirely independent of the car body except to
the extent that a pin or projection from the motor should encounter a corresponding
projection on the car body to prevent the structure from revolving. My transmitting
mechanism may thus be readily removed for repairs, &c.
I will now explain the practical working of my invention.
Referring to Fig. 2 consider the gear I fastened to the wheel G and the gear N
concentric to the shaft A, and imagine that the gear N is held stationary. Then
suppose that the gear I has 236 teeth and the gear N has 228. If now the shaft A
and eccentric F are revolved one full turn in the direction of the arrow. the point of
contact will revolve a full turn around and the enveloping gear I will roll tooth for
tooth on the inner one N with the result that when the full turn is completed the
tooth on the gear I which originally stood at the point of deepest contact, i.e. on the
vertical line through centres of shaft and eccentric, will have passed that line to
the left, that is, in the direction of the circular arrow by eight teeth, the rolling
contact with the 228 toothed gear N having only called for 228 of the 236 teeth on
gear I. Therefore it is evident that while the shaft A made a full revolution the
wheel G only made or about
of a revolution in the same direction.
59
236
2
Now consider the external gear K on the wheel G, and the internal gear P, con-
centric with the shafts, and let us suppose that while the latter gear P is held
stationary the shaft A and eccentric F are revolved one turn in the direction of the
arrow. Let us also suppose that K and P have respectively 154 and 162 teeth. As
the rolling contact takes place tooth by tooth, before the eccentric can come back to
its original position the 162 teeth of the stationary gear K called for 162 tooth con-
tacts with gear P, and as the latter has only 154 teeth it follows that the original
deepest contact tooth on gear P has failed to return to its original position by 8 teeth.
In other words the gear P has swung an arc of 8 teeth in the direction opposite to
that of the prime mover so that when the shaft A turned in one revolution the
8
gear P moved or of a turn in the opposite direction.
.154 71
The above two examples, thus show that when the prime mover and eccentric are
revolved in a given direction, an internal gear on the disc has an angular motion

page_text: relatively to the external gear concentric to the shaft with which it meshes in the
direction of the shaft, while an external gear on the disc- has an angular motion-in
the opposite direction to that of the shaft relatively to, the internal gear concentric
with the shaft with which it, meshes. tie
T
Now let us consider (Fig. 1) the gear N having 228 teeth, supposed for the time
being to be held stationary, gear I on wheel G with 236 teeth, gear H on wheel G
with 228 teeth and internal gear M 236 teeth integral with the final mover. One
revolution of the wheel G would leave the tooth on gear M originally at deepest
contact, 8 teeth behind the tooth on gear M with which it meshed before the turn
was given, or inversely we may say that for each revolution of the shaft A and
eccentric F the gear M will have received an angular advance of 8 teeth relatively
to H and in the direction of the rotation of the shaft.
Now, N being stationary one turn of the shaft A causes the gear. N to gain an
8
advance of 8 teeth, an angular advance of of a turn in the direction of rotation
236
8
236
of the shaft. This angular advance of of a turn corresponds to one of
:.8
236
:
-
15,728
236
or of a turn,
× 228 or 7,728 teeth on gear H. As H meshes tooth for tooth with M it follows
that the rotation of I on N has forced M ahead 7,228 teeth. On the other hand as
explained before the rotation of H in M forced the latter 8 teeth ahead. The total
advance of M is then 7,728 +8 teeth, an angular advance of
In other words for each full turn of the prime mover A the final mover B attached to
the gear M makes of a turn, or in other words again, the relative speeds of the
two shafts are 15 to 1.
.15
15
The combination above assumed, however, of one stationary gear concentric with
the shafts, a gear concentric and secured to the final mover, these gears meshing
respectively with two gears on a wheel revolving loosely on an eccentric on the prime
mover has been used heretofore. Its usefulness, however, is limited by the fact that
one gear, which I term the fulcrum gear, has to be stationary and therefore only
one fixed differentiation of speed is possible between the final and the prime
movers.
There are innumerable instances in the transmission of power, as when the prime
mover has a high rotative speed, where it is very important to be able to vary at will
the speed of the final mover and even reverse said final mover without stopping or in
any way altering the speed of the prime mover, and it is to attain this object that I
have evolved the present invention.
In Fig. 1 the three gears O, P, N concentric with the shaft, their supporting
sleeves or fittings Q, R, S and the brake wheels W, W1, W2 are shown and described
loose and independent of each other, although each gear is rigidly connected with its
corresponding brake wheel. I will explain what takes place when the prime mover A
is revolved. The resistance of the final mover will hold the gear M stationary. The
gear H will roll on M and on the principle explained before, for each revolution of the
prime mover and eccentric the gear H will swing eight teeth in the direction opposite
to that of the shaft an angular movement of of a turn, which angular move-
an
8
228
⚫ments amounts to × 236 or 8.28 teeth on the gear I. Again, the revolution of
8
228
the eccentric. causes the gear N by its rolling action inside of gear I to move 8 teeth
in the direction opposite to that of the shaft so that the total effect on gear N of one
full revolution of the prime mover is to swing this gear N 8.28 + 8 or 16.28 teeth in
the direction opposite that of the prime mover. This represents an angular move-
14.

page_text: one time as illustrated in Figure 3. Furthermore I arrange the connections to the
several brakes in such an order on the dial of the rheostat that it is not possible for
the operator to shift directly from a very high to a very low train of gearing or vice
versa without in so doing throwing into action intermediate trains of gearings for a
period of time which however small will be sufficient to prevent any jerky action of
the mechanism. Likewise the final mover or axle cannot be reversed without the
brakes having been applied thereto. This is clearly illustrated in Figure 3.
These successive changes in the rate of differentiality of the successive trains of
gearings brought into action in the act of stopping will have the result of producing
a cushioning effect and of avoiding jars and jerks.
It is to be understood I claim my invention adapted either as a reversing
differential gear alone, or as a changeable differential gear alone, or both as reversing
and a changeable differential gear; and that I do not limit my claims to any
parlicular kind of brakes.
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. A power transmitting mechanism consisting essentially of a revoluble primary
shaft, an eccentric or eccentrics fixed thereon, a plurality of fulcrum gear wheels
concentric with said shaft and revoluble independently thereof and of each other,
means for controlling the rotation of the fulcrum gear wheels independently of each
other, a secondary gear wheel or wheels concentric with the primary shaft and
..revoluble independently thereof, and a plurality of eccentrically mounted and driven
gear wheels rolling on the respective fulcrum gear wheels and having a gear or gears
rolling on the secondary gear wheel or wheels; said mechanism being adaptable
either as a reversing differential gear alone, or as a changeable differential gear
alone, or both as a reversing and changeable, differential gear.
2. Means for controlling the power transmitting mechanism herein described
consisting of brakes or devices for controlling the rotation of the fulcrum gear wheels
and also of the secondary gear independently of each other, a handle or operator, and
'operating connections between the said handle or operator and the fulcrum gear
controlling means and the secondary gear controlling means.
Dated this 19th day of June 1899.
BOULT & WADE,
Agents for the Applicant.

page_text: ment of
16.28
228
or of a turn. Hence for every turn of the prime mover the gear
14
1
N and its brake wheel W revolve. of a turn in the opposite direction.
14
In a like manner the gear 0 (0 'having 100 teeth and J 108) and its brake
wheel W will move for every turn of the motor and in the opposite direction
8
x. 1088 or 11.784 teeth; in other words
.236
11.784
100
or
1
8.49
of a turn.
On the other hand the gear P (P having 162 and K 154 teeth) and its brake
-wheel W¹ will move for every turn of the prime mover
8
228
x.154, viz. 5.4 teeth in
2.6
162
62.3
.of
the opposite and 8 teeth in the same direction, or .8. less 5.4 = 2.6.teeth in the same
direction as the shaft. This corresponds with an angular motion of or
a'turn.
Thus with the mechanism shown in Fig. 1 when the prime mover is running and
the brake wheels free, we will have the final mover at rest, the brake wheels W
and W2 revolving at reduced speed in the direction opposite to that of the motor and
the brake wheel W₁ moving at a reduced. speed.in the same direction.
Now to start the final mover, clamp the brake,wheel W, thereby rigidly locking
the gear N. At each revolution of the eccentric the wheel G revolves of a turn
8
.236
8
ahead or × 228 = 7.728 teeth on gear H which 'latter, gear forces gear M ahead
236
that same amount of teeth plus 8, due to its own intrinsic action on 'M. The latter
15:728
receives therefore a total angular advance of
236
of the prime mover.
1
or of a turn in the direction
+15
The only requisite is that the grip of the shoe on 'the brake. should be sufficient to
'hold'the brake wheel rigid and stationary against the resistance of the final mover,
said grip on the "brake providing the fulcrum through which to exert the
power.
In the same manner the tightening of the brake W2 will cause the final, mover to
be revolved
of a turn in the direction of
8
x 228 +8 or 24.88 or
,108
24.88
236
1
9.48
the prime mover.
The tightening of brake wheel W₁,will cause the final mover to revolve. 8.teeth in
-8
154
the direction of the prime mover and × 228 or 11.84 teeth in the opposite
direction; the result being that the final mover will be driven at a rate
of
3.84
1
or in the opposite direction to the prime mover.
236 61.4
In the adaptation of my invention shown in Fig. 3, the proportions of gears shown
give the following speeds:
With brake wheel V2 clamped, axle backs at a speed of 1 to 8.92.
With brake wheel f clamped axle backs at a speed of 1 to 56 58.
With brake wheel k, k axle stops and is braked.
With brake wheel e axle goes ahead at a speed of 1 to 57.65.
With brake wheel d axle goes ahead at a speed of 1 to 26.
With brake wheel V1 axle goes ahead at a speed of 1 to 9.95; and
With brake wheel V3 axle goes ahead at a speed of 1 to 6.65.
The brake I prefer to use in connection with all transınitters of which the prime
mover is electrically operated are electrically operated brakes. They will be
controlled by a rheostat having its seginents connected with the several brake shoes
in such manner that no two brakes (except the two on the axle) can be locked at the

page_text: one time as illustrated in Figure 3. Furthermore I arrange the connections to the
several brakes in such an order on the dial of the rheostat that it is not possible for
the operator to shift directly from a very high to a very low train of gearing or vice
versa without in so doing throwing into action intermediate trains of gearings for a
period of time which however small will be sufficient to prevent any jerky action of
the mechanism. Likewise the final mover or axle cannot be reversed without the
brakes having been applied thereto. This is clearly illustrated in Figure 3.
These successive changes in the rate of differentiality of the successive trains of
gearings brought into action in the act of stopping will have the result of producing
a cushioning effect and of avoiding jars and jerks.
It is to be understood I claim my invention adapted either as a reversing
differential gear alone, or as a changeable differential gear alone, or both as reversing
and a changeable differential gear; and that I do not limit my claims to any
parlicular kind of brakes.
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. A power transmitting mechanism consisting essentially of a revoluble primary
shaft, an eccentric or eccentrics fixed thereon, a plurality of fulcrum gear wheels
concentric with said shaft and revoluble independently thereof and of each other,
means for controlling the rotation of the fulcrum gear wheels independently of each
other, a secondary gear wheel or wheels concentric with the primary shaft and
revoluble independently thereof, and a plurality of eccentrically mounted and driven
gear wheels rolling on the respective fulcrum gear wheels and having a gear or gears
rolling on the secondary gear wheel or wheels; said mechanism being adaptable
either as a reversing differential gear alone, or as a changeable differential gear
alone, or both as a reversing and changeable, differential gear.
2. Means for controlling the power transmitting mechanism herein described
consisting of brakes or devices for controlling the rotation of the fulcrum gear wheels
and also of the secondary gear independently of each other, a handle or operator, and
operating connections between the said handle or operator and the fulcrum gear
controlling means and the secondary gear controlling means.
Dated this 19th day of June 1899.
BOULT & WADE,
Agents for the Applicant.