Improvements in Speed Reducing or Speed Multiplying Gear.
Year: 1899

page_text: Date of Application, 22nd Dec., 1899
Improvements in Speed Reducing or Speed Multiplying Gear.
I, SAMUEL CLELAND DAVIDSON, of Sirocco Engineering Works, Belfast, Ireland,
Merchant, do hereby declare the nature of this invention to be as follows:-
My invention has reference to speed reducing and speed multiplying gear for
transmitting driving power at a lower or higher rotary speed from the
revolving shaft (hereinafter referred to as the driving shaft) of electric or other
motors, such as turbines or engines, to another shaft in concentric alignment
therewith (hereinafter referred to as the driven shaft).
The objects of my invention are to transmit a lower or higher rotary motion
from driving to driven shafts in concentric alignment with one another, by a
balanced arrangement of gearing to obviate side thrust on the terminals of both
shafts, and thereby minimise friction in their bearings and loss of power there-
from, and also to have said gearing partly immersed and revolving in a bath of
oil or other lubricating fluid, so as to minimise working friction and noise in
said gearing.
According to one modification of my invention I project the end of the driving
shaft through a bearing in one side of a gear chamber (hereinafter referred to as
the gear box) and mount a pinion on its inner end, and on same side of said
gear box have bearings on diametrically opposite sides of, or (when more than
two bearings are used) spaced at equal distances apart around said pinion. Each
of said bearings carries one of the ends of two or more spur wheel shafts, the
spur wheels on which at that end are of equal diameter and gear into the
pinion of the driving shaft which is either smaller or larger than the spur
wheels, according as the speed of the driving shaft is to be reduced or multiplied.
The opposite ends of the spur wheel shafts are similarly carried in bearings on
the opposite side of the gear box, and are each fitted with secondary spur wheels
of equal diameters one to the other, but smaller or larger than those gearing into
the pinion on the driving shaft, as may be required in the train of the gearing.
These secondary spur wheels gear into a pinion mounted on the end of the
driven shaft which projects into the gear box through a bearing in the side
thereof, concentric and in alignment with the driving shaft. The bearings in
the two opposite sides of the gear box are thus identical in position and arrange-
ment. These opposite sides of the gear box are made with inwardly
projecting flanges around their outer edges, with facing flanges thereon,
as
bolted together so to form
oil-
whereby the
tight joint between them, and to constitute the complete gear box, in which
suitable supply and overflow orifices or pipes are provided for filling in and
regulating the level of the lubricating fluid inside it, into which fluid the larger
gear wheels dip, and splash it freely over the smaller gear wheels, and around the
ends of the bearings within the gear box, which are thus all so efficiently
lubricated as to reduce friction and noise of the gear wheels to a minimum.
two sides are
an
Lugs may be employed upon the exterior of the gear box, to connect same to
the motor, and hold it rigidly in position relatively thereto; or feet may be

page_text: cast on and form part of the gear box, wherewith to secure it upon an extension
of the bed-plate on which the motor itself is mounted.
The above-described arrangement of gearing can be so adjusted as to rotate
the driven shaft at any required speed relatively to that of the motor. shaft.
According to another modification, I carry each of the spur wheel shafts in
one bearing only, which is located between the pair of spur wheels upon each
shaft, by inserting between the jointing faces of the two herein before described
opposite sides of the gear box, what I hereinafter refer to as an intermediate
bearing plate.
In this modification I preferably project the ends of both the driving and driven
shafts sufficiently within the gear box for them to enter a corresponding bearing
on each face of said intermediate bearing plate, between which and the bearing
in the side of the gear box, the pinions are mounted on the driving and driven
shafts respectively. The employment, in the intermediate bearing plate, of
these additional bearings for the ends of the driving and driven shafts, is desir-
able where high power is being transmitted, as they not only increase the firm-
ness of the pinions thereon, but also ensure their centres being true to the
centres of the spur wheel shafts; and when extra high power has to be trans-
mitted, each end of the spur wheel shafts may also, for same reasons, be projected
into bearings in the sides of the gear box, so that the spur wheels are supported
by bearings on each side. Said intermediate bearing plate has within the gear
box openings at bottom and top so as to allow a free circulation of the lubricating
fluid and contained air through same, from one side of the gear box to the other,
when the gear wheels are revolving.
1000
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London,
Chartered Patent Agents.
I, SAMUEL CLELAND DAVIDSON, of Sirocco Engineering Works, Belfast, Ireland,
Merchant, 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:-
My invention has reference to speed reducing or speed multiplying gear for
transmitting driving power at a lower or higher rotary speed from the revolving
shaft (hereinafter referred to as the driving shaft) of electric or other motors,
such as turbines or engines, to another shaft in concentric alignment therewith
(hereinafter referred to as the driven shaft).
The objects of my invention are to transmit a lower or higher rotary motion
from driving to driven shafts in concentric alignment with one another, by a
balanced arrangement of gearing to obviate side thrust on the terminals of both
shafts, and thereby minimise friction in their bearings and loss of power there-
from, and also to have said gearing partly immersed and revolving in a bath of
oil or other lubricating fluid, so as to minimise working friction and noise in said
gearing.
According to one modification of my invention I project the end of the driving
shaft through a bearing in one side of a gear chamber (hereinafter refered to as
the gear box) and mount a pinion on its inner end, and on same side of said gear
box have bearings on diametrically opposite sides of, or (when more than two

page_text: bearings are used) spaced at equal distances apart around said pinion. Each of
said bearings carries one of the ends of two or more spur wheel shafts, the spur
wheels on which at that end are of equal diameter and gear into the pinion of
the driving shaft which is either smaller or larger than the spur wheels, accord-
ing as the speed of the driving shaft is to be reduced or multiplied. The opposite
ends of the spur wheel shafts are similarly carried in bearings on the opposite
sides of the gear box, and are each fitted with secondary spur wheels of equal
diameters one to the other, but smaller or larger than those gearing into the
pinion on the driving shaft, as may be required in the train of the gearing.
These secondary spur wheels gear into a pinion mounted on the end of the driven
shaft which projects into the gear box through a bearing in the side thereof,
concentric and in alignment with the driving shaft. The bearings in the two
opposite sides of the gear box are thus identical in position and arrangement.
Between these opposite sides of the gear box I insert what I hereinafter refer to
as an intermediate bearing plate in which I provide bearings as supports for
the spur wheel shafts, said bearings being located between the pair of spur
wheels on each shaft. By these means the spur wheels are supported by bearings
on each side. The opposite sides of the gear box are made with outwardly pro-
jecting flanges around their outer edges, with facing flanges thereon, between
which the faced flanges of the intermediate bearing plate are inserted and where-
by the two sides of the gear box and the intermediate bearing plate are bolted
together so as to form an oil-tight joint between them, and to constitute the
complete gear box, in which suitable supply and overflow orifices or pipes are
provided for filling in and regulating the level of the lubricating fluid inside it,
into which fluid the larger gear wheels dip, and splash it freely over the smaller.
gear wheels and around the ends of the bearings within the gear box, which are
thus all so efficiently lubricated as to reduce friction and noise of the gear
wheels to a minimum.
The intermediate bearing plate has within the gear box openings at bottom
and top so as to allow a free circulation of the lubricating fluid and contained
air through same, from one side of the gear box to the other, when the gear
wheels are revolving.
Lugs may be employed upon the exterior of the gear box, to connect same to
the motor, and hold it rigidly in position relatively thereto, or feet may be cast
on and form part of the gear box, wherewith to secure it upon an extension of
the bed-plate on which the motor itself is mounted. The gear box generally
may be constructed in two or more parts bolted together with horizontal or
vertical joint or joints as may be found most convenient in each case.
The above-described arrangement of gearing can be so adjusted as to rotate
the driven shaft at any required speed relatively to that of the motor shaft.
According to another modification I dispense with the bearings in the sides
of the gear box for the spur wheel shafts and carry each of the spur wheel shafts
in the one bearing only, which is located in the intermediate bearing plate be-
tween the pair of spur wheels upon each shaft.
In this modification, as also in the first described modification, I preferably
project the ends of both the driving and driven shafts sufficiently within the
gear box for them to enter a corresponding bearing on each face of said inter-
mediate bearing plate, between which and the bearing in the side of the gear
box the pinions are mounted on the driving and driven shafts respectively. The
employment in the intermediate bearing plate, of these additional bearings for
the ends of the driving and driven shafts, is desirable where high power
being transmitted, as they not only increase the firmness of the pinions thereon,
but also ensure their centres being true to the centres of the spur wheel shafts.
Figures 1, 2, 3 and 4 show a modification in which the gear box is made in
halves, bolted vertically.
T1 being a vortical section on the line A R of Times 2

page_text: Figure 3 a vertical section on the line E-F of Figure 2, and
Figure 4 an end elevation of Figure 1.
Figures 5, 6, 7 and 8 show another modification in which the gear box is
similarly made in halves, bolted vertically, but without outside bearings for
carrying side shafts.
Figure 5 being a vertical section on the line G-H of Figure 6.
Figure 6 a horizontal section on the line I-J of Figure 5.
Figure 7 a vertical section on the line K-L of Figure 5, and
Figure 8 an end elevation of Figure 5.
Referring first to Figures 1 to 4 inclusive, the gear box in which the gearing
is enclosed is made in halves 1 and 2 which are connected together with an oil-
tight vertical joint by means of bolted flanges 1 and 2ª respectively between
which is secured the peripheral flange 3ª of a vertical intermediate bearing plate 3
that extends centrally across the gear box from end to end. The two halves of
the gear box are provided with feet 1b, 2b by means of which the gear box cau
be boited to any suitable foundation. Bearings 4 are cast on one end of the gear
box to carry a shaft 5, and bearings 6 are cast on the opposite end of the gear
box, to carry a shaft 7. The shafts 5 and 7 are co-axial and opposite to each
other. Bearings S are cast on one side of the gear box laterally of the shaft 5
to take one end of a shaft 9, and bearings 10 are cast on the opposite side of the
gear box, and in the same direction laterally of the said shaft 5 to take the other
end of the said shaft 9. Bearings 11 are cast on the gear box on the same side
of, but in the opposite lateral direction to, the bearings 8, to take one end of a
shaft 12, and bearings 13 are cast on the corresponding and opposite side of the
gear box to take the other end of the said shaft 12. The side shafts 9 and 12
are parallel to each other and to the common axis of the central shafts 5 and 7;
they are also equi-distant from said common axis. 14 is a spur pinion wheel
fixed on the end of the shaft 5 inside the gear box, and 15 is a spur wheel fixed
on the shaft 9 inside the gear box and gearing with the pinion 14.
16 is a spur
pinion also fixed on the shaft 9 but gearing with a spur wheel 17 fixed on the
shaft 7. 18 and 19 are respectively a spur pinion and a spur wheel fixed on the
shaft 12 and gearing respectively with the wheel 17 and pinion 14. All the
pinion and wheels 14, 15, 16, 17, 18 and 19 are inside the gear box. The pinion 14
and wheel 17 gear respectively with the wheel 15 and pinion 16 on one side,
and with the pinion 18 and wheel 19 on the opposite side. The pinions 14, 16
and 18 have equal diameters, and the wheels 15, 17 and 19 have also equal
diameters.
The side shaft 9 is also carried in an additional bearing 20 which is cast in
the intermediate bearing plate and is located between the wheels 15, 16 on
said shaft, and the other side shaft 12 is also carried in an additional bearing 21
which is also cast in the intermediate bearing plate 3 and located between the
wheels 18, 19 on said shaft. The intermediate plate 3 has also cast with it
centrally located co-axial bearings 22 and 23 which carry respectively the inner
ends of the shafts 5 and 7. The employment in the intermediate plate 3 of the
additional bearings 22, 23 for the ends of the central shafts 5 and 7 is desirable
where high power is being transmitted as they not only increase the firmness of
the pinions on said shafts, but also ensure the centres of said shafts being truely
parallel to the centres of the side shafts 9 and 12.
The intermediate plate 3 has within the gear box openings 24, 25 at top and
bottom so as to allow a free circulation of the lubricant and obtained air through
the said openings from one side of the gear box to the other when the gear
wheels are revolving.
26 is a movable plate covering the hole. 27 which is an inlet to allow of intro-
ducing lubricant into the gear box. 28 is an outlet hole for withdrawing the
lubricant from the gear box. The shafts 5 and 7 may be either the driving or
driven shafts according as the speed is to be reduced or increased.
The pinion 14 on the shaft 5 is either smaller or larger than the spur wheels

page_text: according as the speed of the driving shaft 5 is to be reduced or multipled 'in
transmission to the driven shaft 7. The larger wheels dip into the lubricant
contained in the gear box and splash it freely over the smaller wheels and
around the ends of the bearings within the gear box which are thus all so
efficiently lubricated as to reduce friction and noise of the wheels to a minimum.
The side thrusts due to the engagement of the wheels 14 and 15 with each
other and of the wheels 17 and 16 with each other on one side of the shafts 5
and 7 are exactly and respectively balanced by the oppositely directed and equal
side thrusts due to the engagement of the wheels 14 and 19 with each other and
of the wheels 17 and 18 with each other on the opposite side of the said shafts 4
and 6.
The bearings 8, 10 and 11, 13 for carrying the ends of the side shafts 9, 12 are
provided for the purpose of supporting the wheels 15, 16, 18, 19 by bearings on
each side so as to enable extra high power to be transmitted. In ordinary cases
of transmission of light and medium powers these bearings may be dispensed
with and the shafts 9 and 12 be supported solely by the bearings 20 and 21 in
the intermediate bearing plate as shown by the modification illustrated in
Figures 5, 6, 7 and 8.
In this modification the gear box is formed in two vertical halves 29, 30
jointed oil tight by means of bolted flanges 29ª, 30" between which is secured
the peripheral flange 3ª of the intermediate plate 3. The intermediate plate has
cast with it bearings 20 and 21 for the side shafts 9 and 12, and also the central
additional bearings 22 and 23 for the ends of the shafts 5 and 7. The gear box
half 29 has cast with it the bearings 4 for the shaft 5 and the gear box half 30
has cast with it the. bearing 6 for the shaft 7.
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. In speed reducing or speed multiplying gear, the combination of two
central rotary shafts arranged in line with each other, a pinion on the end of
the first central shaft, and a toothed wheel on the adjacent end of the second
central shaft, a first side shaft and a second side shaft located on opposite sides
of the common axis of the two central shafts, a toothed wheel on the first side
shaft gearing with the pinion on the first central shaft, and a pinion on the first
side shaft gearing with the toothed wheel on the second central shaft, a toothed
wheel on the second side shaft gearing with the pinion on the first central shaft
and a pinion on the second side shaft gearing with the toothed wheel on the second
central shaft, with bearings for the two central shafts, and with an intermediate
plate provided with bearings for the two side shafts, substantially as set forth.
2. In a speed reducing or speed multiplying gear, the combination of two
central rotary shafts arranged in line with each other, a pinion on the end of the
first central shaft, and a toothed wheel on the adjacent end of the second central
shaft, a first side shaft and a second side shaft located on opposite sides of the
common axis of the two central shafts, a toothed wheel on the first side shaft
gearing with the pinion on the first central shaft, and a pinion on the first side
shaft gearing with the toothed wheel on the second central shaft, a toothed wheel
on the second side shaft gearing with the pinion on the first central shaft and
pinion on the second side shaft gearing with the toothed wheel on the second
central shaft, with bearings for the two central shafts, and with an intermediate
plate provided with bearings for the two side shafts, and with central bearings
for the adjacent ends of the two central shafts, substantially as set forth.
3. In speed reducing or speed multiplying gear, the combination of two
central rotary shafts arranged in line with each other, a pinion on the end of
the first central shaft, and a toothed wheel on the adjacent end of the second
central shaft. a first side shaft and a second side shaft located on opposite sides
of the common axis of the two central shafts, a toothed wheel on the first side.

page_text: shaft gearing with the pinion on the first central shaft, and a pinion on the first
side shaft gearing with the toothed wheel on the second central shaft, a toothed
wheel on the second side shaft gearing with the pinion on the first central shaft
and a pinion on the second side shaft gearing with the toothed wheel on the
second central shaft, with a gear box made in halves bolted together enclosing
the whole of the toothed gearing and provided with bearings for the two central
shafts, and with an intermediate plate provided with bearings for the two side
shafts, and with central bearings for the adjacent ends of the two central shafts,
substantially as set forth.
4. In speed reducing or speed multiplying gear, the combination of two
central rotary shafts arranged in line with each other, a pinion on the end of
the first central shaft and a toothed wheel on the adjacent end of the second
central shaft, a first side shaft and a second side shaft located on opposite sides
of the common axis of the two central shafts, a toothed wheel on the first side
shaft gearing with the pinion on. the first central shaft and a pinion on the first
side shaft gearing with the toothed, wheel on, the second central shaft, a toothed
wheel on the second side shaft gearing, with the pinion on the first central shaft
and a pinion on the second side shaft gearing with the toothed wheel on the
second central shaft, with a gear box made in halves bolted together and enclos-
ing the whole of the toothed gearing, and provided with bearings to carry the
two central shafts, and also with bearings to carry the ends of the two side
shafts, with an intermediate-plate provided with central bearings to carry the
adjacent ends of the two central shafts, and also with bearings to carry the two
side shafts,, substantially as set forth.
5. The improved speed reducing or speed, multiplying gear, as described and
shown in Figures 1-4 and Figures 5-8 of the accompanying drawings.
1
Dated this 21st day of September 1900.
J. C. MEWBURN & ELLIS,
55 and 56, Chancery Lane, London,
Chartered Patent Agents.