Improvements in Variable and Reversible Speed Gears.
Year: 1896

page_text: Date of Application, 18th Dec., 1896
Complete Specification Left. 18th Sept. 1897-Accepted. 4th Dec. 1897
PROVISIONAL SPECIFICATION.
Improvements in Variable and Reversible Speed Gears.
I, ARTHUR GEORGE COOKE, M.A., Engineer, of 60, Coolhurst Road, Crouch End,
in the County of Middlesex, do hereby declare the nature of this invention
to be as follows:-
The object of my invention is to provide a simple and efficient kind of variable
speed gear by means of which the motion of a driver, such as an engine or electric
motor, may be communicated to a follower, or machinery required to be driven,
the speed ratio of the gear being capable of variation at will or automatically,
without stopping the machinery or causing heavy shock or strain during the
variation, or the direction of motion of the follower reversed while the driver
moves uniformly in the same direction.
By my invention I am able to obtain a gear which is at the same time efficient,
strong, and light; it is therefore especially adapted to cycles, motor cars, and the
like. But with suitably modified constructional details it is also applicable to
cranes, lathes, lifts, and in fact to any machinery in which the speed ratio of
driver to follower is required to be frequently changed, or the direction of motion
reversed.
In the form suited to reversing the direction in which the follower is driven,
it is applicable to purposes where automatic regulation is required, as in electrical
and other apparatus, and to the steering of ships, training of guns and the like by
the electrical control of the direction of motion by a distant operator.
In carrying out my invention I employ two or more pinions fast upon the same
axle, and in required positions thereupon, these pinions also being capable of each
rolling as epicyclic or hypocyclic wheels upon or within one or two other wheels
on the same axis, but which can rotate independently of one another, the axle of
the said epicyclic or hypocyclic pinions being mounted upon a wheel, hereinafter
referred to as the "differential wheel", rotating upon the same axis as the in-
dependent wheels aforesaid.
In one form of my invention I connect one of the independent wheels (or
"driver") upon which one of the epicyclic pinions, rolls to the driving mechanism,
and another independent wheel (the "follower") to the machinery to be driven.
To the differential wheel and to the remaining independent wheels brakes can be
applied at will or automatically by suitable mechanism; these brakes are of such
a form that they can be applied gradually to bring the corresponding wheel
gradually to rest, for which purpose the band-brake encircling a brake wheel is
eminently suitable.
When the brake is applied to the differential wheel so as to bring it to rest, all
other brakes being released, the motion of the driver is communicated to the
follower through the epicyclic or hypocyclic pinions, which now rotate only
about a fixed axle, either through only one of them, if the teeth of driver and
follower mesh with the same pinion, or if they mesh with different pinions,
through both of these pinions in a manner similar to that commonly employed in

page_text: the "back-gear" of a lathe. The remaining independent wheels meanwhile
rotate idly.
When the brake is released from the differential wheel and applied to one of
the independent wheels, so as to bring it to rest instead, the motion is trans-
mitted by one of the pinions rolling as an epicyclic or hypocyclic wheel upon this
stationary wheel, while its axle rotates with the differential wheel, and the same or
a different pinion drives the follower with a different speed ratio, or in a different
direction, from that which was obtained in the former case, according to the
relative sizes of the various wheels used.
In other forms of my invention. I use the differential wheel above referred to
either as driver or follower, instead of one of the independent wheels as described
above.
If it is desired to avoid the use of mitre wheels, I mount the common axle of
the epicyclic or hypocyclic pinions upon the differential wheel so as always to
remain parallel to the common axis of the differential wheel, and other indepen-
dent wheels. I also, in order to obtain greater mechanical strength, and to
Lalance the differential wheel, use two or more similar and symmetrically
arranged sets of pinions upon the same differential wheel.
The release of all the brakes allows the driver and follower to rotate indepen-
dently; the application of more than one brake tends to stop both driver and
follower; instead of separate brakes being applied as above indicated, if any two
independent wheels are attached together, which may readily be effected by any.
convenient form of friction clutch, the driver and follower rotate together with-
out. intermediate gearing. Such clutch device may be operated by a lever adapted
to. impart to one of the independent wheels a traversing motion by which it is
brought into contact with the differential wheel; or I may arrange a clutch
preferably of the friction type between any of the independent wheels, or between
any independent wheel and driver or follower, or directly between driver and
follower, as circumstances may demand, whereby the whole of the gear may be
rotated as a rigid mass.
Dated this 18th day of December, 1896.
J. C. CHAPMAN,
Agent.
Improvements in Variable and Reversible Speed Gears.
I, ARTHUR GEORGE COOKE, M.A., Engineer, of 60, Coolhurst Road, Crouch End,
in the County of Middlesex, 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 relates to variable and reversible speed gears by means of which
the motion of a driver such as an engine or electric motor is communicated to a
follower or machinery to be driven. The present invention has for one of its
objects to provide a simple efficient and easily worked multiple speed gear in which
the speed ratio is capable of variation at will or automatically without stopping
the machinery or causing heavy shock or strain during the variation. A further
object of the invention is to provide means whereby the direction of motion of
the follower or driven machinery or axle can be reversed whilst the driver moves
uniformly in the same direction. The invention also relates to certain details
of construction which are fully described hereinafter and pointed out in the claims.
By my invention I obtain a gear which is at the same time efficient, strong,

page_text: and light; and therefore especially adapted to cycles, motor cars, and the like.
But with suitably modified constructional details it is also applicable to cranes,
lathes, lifts, and in fact to any machinery in which the speed ratio of driver to
follower is required to be frequently changed, or the direction of motion reversed.
According to my invention the motion of a driving wheel is transmitted to the
following wheel through a combination or a plurality of combinations comprising
two or more pinions in each, rotating together upon the same axle, the teeth of
said driver and follower meshing with those of the same pinión or of different
pinions of each combination used, the axles of these combinations of pinions being
mounted on another or "differential wheel", in order to allow of a further
motion in addition to the rotary motion of the combinations of pinions. For
obtaining various speed ratios and a reversal of motion when required I employ
brakes holding either the differential wheel or some other independent wheel
upon which one of the pinions of each combination then rolls as an epicyclic or
hypocyclic wheel, and I obtain a further speed ratio (of unity) by means of a
clutch between any two elements of the gear whereby it is caused to rotate as a
solid mass.
I can also use the differential wheel as either driver or follower, and
I may vary the details of my invention to obtain three or more speed ratios in
the same direction, or two speed ratios in one direction and one in the reverse
direction as hereinafter shown.
I am aware that two separate alternative differential gears giving different
speed ratios and utilised at different times by a brake acting on an otherwise idle
element of either of them is not new, also that a differential gearing with pairs of
epicyclic pinions instead of single pinions has been constructed, and I lay no claim
to such gears, but what I aim to claim as of my invention is the novel combina-
tion and combinations of the several parts wherein more than two wheels gear
with such pairs of pinions as will be hereinafter fully set forth and defined in the
claims.
Referring now to the accompanying drawings in which similar letters of refer-
ence indicate corresponding parts in all the figures.
Fig. 1 is a central section through my improved variable speed gear. Fig. 2 is
a section on line 1-2 thereof looking to the left. Fig. 3 is a right-hand end
elevation. Fig. 4 is a section through part of an alternative design. Fig. 5. is
a central section of a slightly modified form of my improved three speed gear and
Fig. 6 is a section on line 2-3 thereof showing strengthening stays: Fig. 7 is
a part sectional side elevation showing brake and clutch operating devices, and
Fig. 8 a front elevation of same.
A is a high speed motor shaft and B a pinion keyed fast thereto. H is a
differential or supporting wheel (which is shown with a coned interior surface H
for a three speed gear hereinafter described) having a long sleeve or bearing
rotating upon the shaft A. Upon the sleeve h is fitted a rotary sleeve a to which
sleeve is keyed the follower C and the chain wheel R or equivalent from which
the power is transmitted to the machinery to be driven in the usual way. dis
an end stop for securing the whole in position. Power is transmitted from the
driver B to the follower C through two intermediate pinions D and E keyed to
a common axle F mounted in a long bearing h¹ upon the said differential wheel H.
The pairs of pinions D E are duplicated or triplicated or quadruplicated in
symmetrical positions around the shaft A and the differential wheel H is con-
trollable by a band brake such as M Figs. 7 and 8. When the brake is applied"
the action is similar to that known as the "back gear" for speed reduction in an
ordinary lathe, giving (as shown) a speed ratio of reduction. G is another large
wheel of the form shown (with a coned surface at G for three speeds hereinafter
explained) and rotating on the motor shaft A and it is also provided with a band
brake N, Figs. 7 and 8, and has internal teeth g as shown meshing with those of
the pinion and its fellows. When the brake is applied to wheel G (instead
of H as above described) the pinions D D roll upon the internal teeth as hypo-
cyclic wheels; the wheel H will then rotate slowly giving a second speed ratio

page_text: of less reduction than in the above case. In order to add another speed ratio I
mount the wheel G (which may be called the controlling wheel) so as to be capable
of longitudinal motion upon the shaft A by means of a shifter such as is shown
in Fig. 7 and I employ the coacting coned surfaces G, H, above referred to. The
means for traversing the wheel G may consist of a collar J upon the wheel G
actuated through a pin and fork j, the system of levers J (centred at j¹) and .J3
and slide JS by the main lever P, or any other convenient mechanical means may
be substituted. When full speed is required both the band brakes M N are
released and a traversing motion is given to the wheel G through the device
described which brings it into contact with wheel H through the cone clutch G' H¹
as shown Fig. 1. Then the pinions D E can no longer rotate about their common
axle F and the whole gear is rotated as a rigid mass. The above described gears
give motion in one direction only and my invention further consists in an arrange-
ment for obtaining a reversal of motion in addition to two speed ratios direct.
This is shown in Fig. 4 and consists in the combination with the pinions D and E
of a large follower C (similar to G) with internal teeth gearing with the pinion E:
and mounted on the sleeve a instead of the follower C. Thus the applications
respectively of G or H cause C to rotate in apposite directions reversing the
direction of motion of the chain wheel R as may be required. The wheels G, H
and R may be of any construction or relation suitable to the circumstances of use.
In order to render the controlling gear shown in Figs. 7 and 8 capable of
being operated by one lever P it is centred at p so that side motion as indicated
by the arrows in Fig. 7 will operate the clutch G H with the desired result.
The lever P is also linked at p to the brake strap block M rotating on the shaft m
so that by moving the same lever P in the other direction the brakes M and N
can be operated at will: thus the two lower speeds are obtained by moving the
lever P to the right or left in Fig. 8 and full speed by moving it to the left
in Fig. 7.
In operation with the construction shown in Figs. 1, 2, 3, 7, and 8, assuming
that B'is the driving wheel, C the driven wheel, 1 the primary pinion meshing
with the driving wheel, E the secondary pinion meshing with the driven wheel, H the
supporting wheel for the pinions, and G the controlling wheel, the teeth of which
engage those of the pinion D diametrically opposite the wheel B, the power will
be transmitted through the shaft A, wheel B and pinions D and E to the wheel C,
and the speed will be controlled by the clutch and brakes acting on the wheels G
and H. If a like speed for driving and driven wheels is desired, the wheels G
and H will be clutched together against independent rotation by forcing the
coned face G¹ of the wheel G into the coned face H of the wheel H. Then the
teeth of wheel G will prevent rotation of the pinion D around its axis so that it
and the pinion E must revolve with the wheel B around its axis. The teeth of
the pinion E, meshing with the wheel C, will force it to revolve at like speed
with the wheel B. To obtain a different
different relative speed, the wheels
G and H will be unclutched, whereupon each is movable independently
of the wheels B and C. If the wheel G is then held stationary by its brake, the
rotation of the wheel B will cause the pinion D to roll around on the teeth of the
wheel G, in doing which it will slowly revolve on its own axis, and impart a like
movement to the pinion E, which will revolve the wheel C at a lower speed than
that of the wheel B. The wheel H will be carried around the axis of the wheel B
with the pinions. For a still different speed, the wheel H may be held stationary
by its brake and the wheel G released. In such case, the wheel B will revolve
the pinions D around their axes, causing the wheel G to move in reverse direction
and the pinion E to drive the wheel C at a speed proportioned to the relative
diameters of the pinions and wheels B and C.
Referring to the modification shown in Figs. 5 and 6 I have shown the two
pinions D and E both cut out of one piece of metal and rotating freely on the
axle F. The differential wheel H is made in two parts H H rigidly connected
by the axles F F and arranged as illustrated; by this modification the whole

page_text: gear is self-contained and self protected holding itself securely together without
the aid of any end stop such as d Fig. 1. I also in this construction employ
stiffening stays as shown at S S Fig. 6 between the discs H H whereby great
strength and rigidity are secured. By duly proportioning the gear wheels I am
able to obtain a variety of speed ratios which though generally used for reduction
may obviously be employed for multiplication.
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 variable or reversible or variable and reversible speed gearing comprising
a driving shaft and wheel in combination with a pair or a plurality of pairs of
pinions, each pair rotating together on one axle, a wheel supporting said axle
or axles, the said driving wheel and a follower and an independent wheel each
meshing with one pinion of each pair so that such pinion rolls upon same as an
epi- or hypocyclic pinion, brakes on the supporting and independent wheels and
means for operating same substantially as set forth.
2. A variable or reversible, or variable and reversible speed gearing
comprising a driving shaft and wheel in combination with a pair or
a plurality of pairs of pinions, each pair rotating together on
one axle,
a wheel supporting said axle or axles, the said driving wheel and a follower
and an independent wheel each meshing with one pinion of each pair so that
such pinion rolls upon same as an epi- or hypocyclic pinion, a clutch between
the supporting and independent wheels, and means for operating same, band
brakes on to the supporting and independent wheels and means for operating
same, substantially as described.
3. A variable speed gearing constructed substantially as described with refer-
ence to Figs. 1 to 3, Fig. 4, Figs. 5 and 6 or Figs. 7 and 8 respectively of the
accompanying drawings, for the purposes set forth.
Dated the 18th day of September. 1897.
For the Applicant.
J. C. CHAPMAN.
Chartered Patent Agent, 70, Chancery Lane, London, W.C.