Improvements in and connected with Differential Gearing.
Year: 1893

page_text: Date of Application, 7th July, 1893
Complete Specification Left, 21st Feb., 1894-Accepted, 7th Apr., 1894
PROVISIONAL SPECIFICATION.
Improvements in and connected with Differential Gearing.
1, GEORGE FREDERICK CHUTTER, of Buckingham Street, in the City of
Birmingham, Electrical Engineer, do hereby declare the nature of this invention
to be as follows:-
This invention consists of the hereindescribed improvements in and connected
with differential gearing for imparting from a shaft revolving uniformly variable
rotary motion to another shaft or revolving part such variable motion of the
driven shaft being either effected automatically as by a mechanical or other
governor so as to be in proportion to the work given out or controlled by hand.
My improved gearing is applicable to any of the many purposes for which
differential gearing is used such as for driving bicycles or other velocipedes or for
rolling mills or looms or other machines where differential motion is required.
According to one arrangement of carrying out my invention I mount to run
loosely on the driven shaft which is required to have the differential motion, an
eccentric and embracing and revolving loosely upon this eccentric I provide a
spur or other toothed wheel which I will call A made with internal and external
teeth. The internal teeth of the wheel A gear with a pinion which 1 will call B
and which is fixed on the driven shaft the external teeth of the wheel A gear with
the internal teeth of another internally and externally toothed wheel which I will
call C and which is concentric with the driven shaft and revolves on a sleeve or
boss formed on the eccentric. This wheel C receives motion from a small pinion
which I will call D fixed on the driving shaft. Fixed to or formed with the sleeve
of the eccentric is a brake drum fitted with a brake strap or other means by which
the rotary motion of the eccentric and the wheel A about the driven shaft can be
controlled. Or instead of the brake pulley gearing or other means may be used
to control the motion of the eccentric and wheel A.
When the eccentric is held stationary as by the brake drum and pulley or other
means the wheels A and C merely act as idle wheels and the driven shaft revolves
at a uniform speed in inverse proportion to the number of teeth in the wheel B on
the driven shaft and the pinion D on the driving shaft. If however the brake
drum or controlling mechanism releases the eccentric so that it and the wheel A
can revolve round the driven shaft then the speed of the driven shaft will be
diminished and the minimum speed of the driven shaft will be when the eccentric
is revolving at the same speed as the wheel C. Thus by retarding the speed of
the eccentric round the driven shaft various velocities of the driven shaft can be
obtained. Instead of that shaft on which the eccentric is mounted being the
driven shaft as above described it will be evident that this shaft may be the driving
shaft revolving at the uniform speed and the other shaft on which is the pinion D
may be the driven shaft. In some cases the pinion D will be dispensed with power
and rotary motion being applied by strap or chain or other means directly to the
wheel C.
When my invention is applied to a power propelled carriage or to a bicycle or
other velocipede then the gradient of the road determines the ratio of the gear
that is to say the eccentric with its wheel A revolves either faster or slower or
remains stationary according to the proportion of the gear which required so
that when ascending hills by merely releasing the grip on the brake drum or

page_text: controlling mechanism of the eccentric the proportion of the gear is instantly
increased.
Dated this 6th dox of July 1893
CHARLES BOSWORTH KETLEY,
Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and connected with Differential Gearing.
I, GEORGE FREDERICK CHUTTER, of Buckingham Street, in the City of
Birmingham, Electrical 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 consists of the herein described improvements in and connected
with differential gearing for imparting from a shaft revolving uniformly, variable
rotary motion to another shaft or revolving part such variable motion of the
driven shaft being either effected automatically as by a mechanical or other
governor, so as to be in proportion to the work given out, or controlled by hand.
My improved gearing is applicable to any of the many purposes for which
differential gearing is used such as for driving bicycles or other velocipedes, for
electric tramcars, or other power propelled carriage or for rolling mills, or looms
or for cranes or other hoisting machinery or wire rope hauling appliances or other
machinery where differential motion is required.
I will first describe my improved differential gearing as applied to an electric
tramcar and I will refer to Figs. 1 to 5 both inclusive of the accompanying drawings
of which
Fig. 1 is a cross sectional elevation of my invention applied to one of the axles
of an electric tramcar; Fig. 2 is a front elevation of the same;
Fig. 3 shews how the variable motion of the driven shaft or axle may be
controlled by hand and
Fig. 4 shews how the said controlling of the driven shaft may be effected by a
governor.
The same letters of reference indicate the same or corresponding parts in all
the figures of the drawings.
According to this arrangement of carrying out this invention I mount to run
loosely on the driven shaft E, which in this case is one of the axles of the tramcar,
and which is required to have the differential motion, an eccentric F and embracing
and revolving loosely upon this eccentric I provide a spur or other toothed
wheel A made with internal teeth a' and external teeth a². The internal teeth a¹
of the wheel A gear with a pinion B which is fixed on the driven shaft or axle E
and the external teeth of the wheel A gear with the internal teeth of another
internally and externally toothed wheel C which is concentric with the driving
shaft E and revolves on a sleeve or boss f' formed on the eccentric F. The
internal teeth of the wheel C are marked c' and the external teeth 2. This wheel C
receives motion from the small pinion D fixed on the driving shaft or motor
shaft G. Fixed to or formed with the sleeve f¹ of the eccentric F is a brake
drum H fitted as hereinafter described with a brake strap I or with other means
by which the rotary motion of the eccentric F and the wheel A about the driven
shaft E can be controlled. The eccentric F and wheel A thereon are counter-
balanced by the weighted part of the brake pulley H. Or instead of the brake
pulley H gearing or other means may as hereinafter described be used to control
the motion of the eccentric F and wheel A mounted thereon.
The differential gearing above described operates as follows:-When the
eccentric F is held stationary as by the brake drum H and brake strap 1 or by

page_text: other means as hereinafter described, the wheels A and C revolve but merely act
as idle wheels and the driven shaft E revolves at its maximum speed, which is a
uniform speed in inverse proportion to the number of teeth in the wheel B on the
driven shaft E and the pinion D on the driving shaft G. If however the brake
drum H or other controlling mechanism releases the eccentric F so that it and the
wheel A can revolve round the driven shaft E then the speed of the driven shaft E
will be diminished and the minimum speed of the driven shaft E will be when the
eccentric Fis revolving at a lower speed than the wheel C. Thus by retarding
the speed of the eccentric F round the driven shaft E various velocities of the
driven shaft E can be obtained.
It will be seen that when my invention is applied to a power propelled carriage
such as an electric tramcar, or electric locomotive, or to a bicycle, or other
velocipede, then the gradient of the road determines the ratio of the gear, that is
to say, the eccentric F with its wheel A revolves either faster or slower or remains
stationary according to the proportion of the gear which is required to move the
car, or locomotive, or velocipede, along the road at the desired speed; so that,
when ascending hills, by merely releasing the grip on the brake drum H or other
controlling mechanism of the eccentric F, the proportion of the gear is instantly
increased.
When my improved gear is applied to an electric tramcar, or an electric
locomotive, and the speed is required to be regulated or controlled by hand, I may.
employ such an arrangement of mechanism for this purpose as that shewn by
Fig. 3 for operating the brake strap I on the brake drum H. I arrange the brake
strap I so that it can be operated from either or both ends of the tramcar or
electric locomotive, by making the brake strap pass one or more times round the
brake drum H the ends of the brake strap pointing in opposite directions
towards the ends of the tramcar or electric locomotive. On the platform J at one
end of the tramcar or the foot plate of the locomotive I fix a pillar j' carrying a
vertical spindle on the top of which is the hand wheel³ for turning it. Fixed
to the bottom of this spindle j2 there is a bevel wheel j which gears with another
bevel wheel ja fixed to a short spindle je which by means of a universal joint j' is
connected to the horizontal rod and this horizontal rod is by its being made
square and engaging in the sliding socket end of the rod j connected to that
rod and by the universal joint is connected to the screw which turns in the
nut fixed in the franing " of the bogie which carries the axle E and this
screw is connected by the swivel joints to the brake strap I so that when
the hand wheel 3 is turned in one direction the connecting rods and
screw will also be turned tightening the brake strap
upon the brake
drum H and when the hand wheel is turned in the opposite direction the
rotary movement of the screw 12 will be reversed and the brake strap
slackened on the brake drum H. The universal joints and the sliding
connection of the horizontal rods 10 allow the bogie or framing which
carries the axle E a large amount of swivelling action and play without
affecting the action of the brake strap on the regulating wheel or brake H.
It will be understood that the other end of the brake strap I is connected
to a hand wheel and pillar on the platform at the other end of the tramcar or
electric locomotive by means like those above described and shewn by Fig. 3
so that the gearing can be regulated from either end of the tramcar or electric
locomotive. As the periphery of the brake drum H has to slide round against the
brake strap I a system of rollers may be fixed to the inside surface of the brake
strap I with beneficial results so as to prevent any excess of friction between
the brake strap I and the brake drum H.
I
Fig. 4 shews another arrangement of mechanism which may be employed for
regulating the brake drum H and the axle E. In this case it will be seen that the
brake drum H is made as a spur wheel arranged to drive the governor K through
a train of spur wheels and pinions consisting of the spur pinion with which the
spur wheel H gears, the spur wheel 2 turning with the pinion and gearing with

page_text: another pinion with which turns another spur wheel which gears with another
spur pinion mounted upon the horizontal axis k₁ of the governor K. On this
spindle three floats or beaters (or there may be more or fewer than three)
marked are mounted and arranged to revolve in the circular box or casing ³
which by means of the flexible pipe m is connected to the reservoir N containing a
fluid. This reservoir N is provided with any suitable means by which it can be
raised or lowered from either or both platforms or footboards of the tramcar or
locomotive so that when the reservoir N is raised as shewn by the full lines in
Fig. 4 the fluid will flow therefrom through the pipe m into the box k³ to about the
level shewn and thus check the speed of revolution of the floats or beaters * and
thus retard the brake drum or regulating wheel H and correspondingly increase
the speed of the axle E. Similarly when the reservoir N is lowered as shewn by
the dotted lines in Fig. 4 the level of the fluid in the box will also be lowered
considerably as the greater portion of the fluid will flow into the reservoir N and
thus as the resistance to the rotary motion of the beaters or floats k² is diminished
they and the regulating wheel H will revolve more rapidly and the speed of the
axle E will be correspondingly diminished or entirely arrested. is an air pipe to
allow air to flow in or out of the governor box k³.
a
Or, where it is thought desirable, an electro-magnetic control may be applied to
the regulating wheel H. This I may effect by driving an armature (forming
part of the said electro-magnetic governor) at a quick speed through a train of
weeels from the spur teeth on the regulating wheel H this armature being arranged
to revolve between the poles of an electro-magnet which is wound with a suitable
number of layers of wire the ends of each wire being brought out to a switch-
board whereby the electric current may be passed into one or more layers of wire
when a corresponding amount of magnetism will result, such magnetism governing
the speed of the armature of the governor and through the train of wheels
governing also the speed of the regulating wheel H and the axle E. Thus the
speed of the axle E is governed by a simple movement on the switchboard.
When the armature of the governor is revolving at its maximum speed the car
axle E is standing still notwithstanding the motor is running at full speed and all
the wheels in gear.
In order to prevent the speed of the axle E falling below the minimum speed
required I sometimes find it necessary to attach two pawls such as 010² see Figs. 1
and 2 to the eccentric F as by the pins o¹ o² on which the pawls 01 02 respectively
turn, the ends of these pawls O'O' running over the internal teeth a¹ of the
wheel A on the eccentric F. It is to be understood that only one pawl is used at a
time and where the motor shaft G and axle E are only required to run in one
direction then only one of these pawls is required. The pawl to be used is decided
by the direction in which the axle E is running; for instance when the axle E is
required to run in the direction shewn by the arrow in Fig. 2 then the pawl O' is
used to gear with the teeth a', the other paw! 02 being out of gear so that when
the speed of the axle E falls down to its minimum the teeth a' gear with the pawl O'
so that the eccentric F and wheel A revolve together and prevent the speed of the
axle E being further reduced; similarly when the axle E is required to run in the
opposite direction to that shewn by the arrow indicated in Fig. 1 then the pawl O²
is brought into gear with the teeth a' and the pawl O¹ is put out of gear, having
the same effect, in preventing the speed of the axle E being reduced below its
minimum, as above described when the pawl O' is in gear.
In order to keep one of the pawls Of O2 in gear whilst the other pawl is out of
gear various meaus may be employed such as by the pawls being made as other
pawls are with flat portions to bear upon the spring w which will thus keep the
pawls either in or out of gear.
It will be understood that my invention is applied to cars driven by gas or oil
engines similarly as above described with reference to Figs. 1, 2, 3, 4 and 5 the
pinion D being fixed to the motor shaft of such engine.
When applying my improved gearing above described to cranes or to wire rope

page_text: hauling apparatus in collieries and elsewhere the shaft G may receive rotary motion
from the motor or from a handle or other source such motion and power being
conveyed through the said gearing to the shaft E on which would be fitted the
drum or pulley of the lifting or hauling rope or chain the proportion of the gearing
being regulated to the load by increasing or diminishing the resistance to the
rotation of the eccentric as stated above.
Instead of the shaft E on which the eccentric F is mounted being the driven
shaft as above described it will be evident that this shaft E may be the driving
shaft revolving at a uniform speed and the other shaft G on which is the pinion Ď
may be the driven shaft which is required to revolve at a variable speed.
For some of the purposes to which my said invention is applied, for instance
when my invention is applied to a bicycle or to any other velocipede, the pinion D
will be dispensed with and power and rotary motion can be applied by strap or
chain or other means directly to the wheel C. A method of applying my invention
to a safety bicycle is illustrated on the accompanying drawings by Figs. 5, 6, 7, 8
and 9 of which Fig. 5 is a part side elevation of a bicycle with my invention
applied to the rear or driving wheel; Fig. 6 is a front view of the handle and
steering post shewing how I arrange for operating the brake strap I; Fig. 7 is a
cross section through the driving wheel axle drawn about full size so as to clearly
shew the arrangement of my differential gearing; Fig. 8 is a front view of the
wheel C and pinion B in position on the axle the pinion B being formed in a piece
with or fixed to the hub P of the driving wheel of the bicycle; Fig. 9 is a face
view of the brake H and eccentric and the wheel A. carried thereby.
It will be seen that in this arrangement of my invention the usual driving
chain V drives on to the external teeth c² formed on the wheel C which runs round
a ball bearing W formed round the hub P of the driving wheel. The eccentric F
is formed in a piece with the brake wheel H running in a double ball bearing on
the collar R the wheel A which revolves round the eccentric being made with oval
pin teeth a', see Figs. 7 and 9, so as to gear both with the pinion B and with the
internally toothed wheel C. The brake strap I which passes once round the brake
wheel H is fixed at one end ¹ to a prolongation of the frame R the other end
of the brake strap being jointed to a bell crank lever s¹ which by a rod 2 is
connected to a hand lever sjointed at s to the handle bar X, see Fig. 6, so that
when the outer end of the handle bars is pulled up like a brake lever the brake
strap I is tightened on the brake wheel H. T is the ordinary brake lever connected
by rods t¹ to the usual brake t².
It will be seen that when riding a bicycle or other velocipede fitted with my
improved differential gearing as above described and shewn by Figs. 5, 6, 7, 8 and 9,
the rider can easily alter the gearing so as to ascend any hills with ease or to
increase the gear for running on the level. In increasing the gear for running up
hill the rider has merely to release the grip of the brake strap I on the wheel H so
that the eccentric F and wheels H and A will be free to revolve; and then, when
he is running on the level or down hill, the rider can instantly increase the gear by
gripping the hand lever 3 so as to arrest the motion of the eccentric F and
wheel A.
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 differential gearing, the employment of an eccentric having mounted to
revolve upon it an eccentric toothed wheel which gears with a larger toothed wheel
and with a smaller toothed wheel, said eccentric and large and small toothed
wheels all being arranged to revolve about the same centre, and means for retarding
the rotation of the eccentric and its toothed wheel and thereby increasing or
diminishing the speed of the driven shaft or other driven revolving part,
substantially as hereinbefore set forth.
2. In electric or other tramcars and electric locomotives, transmitting the motive

page_text: power from the motor to the driving wheel axle by means of the improved differential
gearing herein described, that is to say, by means of a toothed wheel (C) revolving
loosely about said axle and gearing with a smaller eccentric toothed wheel (A)
which also gears with a pinion (B) on the driving wheel axle, said wheel (A) being
carried by an eccentric (F) which can revolve about the driving wheel axle and
which is provided with means for retarding the rotary motion of the eccentric so
as to vary the proportion of the gearing between the motor and the driving wheel
axle, substantially as herein described.
3. In a safety bicycle or other velocipede, transmitting the motive power from
the pedal axle to the driving wheel through the improved differential gearing
herein described, that is to say, the endless driving chain driving on to a toothed
wheel (C) revolving loosely about the driving wheel axis and gearing with a
smaller eccentric toothed wheel (A) which also gears with a pinion (B) fixed to the
driving wheel hub, said wheel (A) being carried by an eccentric which can revolve
about the driving wheel axis and which is provided with means for retarding the
rotation of the eccentric so as to vary the proportion of the gearing, all
substantially as hereinbefore described with reference to Figs. 5, 6, 7, 8 and 9 of
the accompanying drawings.
Dated this 19th day of February 1894.
CHARLES BOSWORTH KETLEY,
Agent for the Applicant.