Year: 1897

page_text: FRANK BRYAN 87, Wellesley Road Gunnersbury, London, W. Electrical Engineer,
do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in the means for transmitting power by
rotary motion through the medium of chains & chain wheel gearing or the like, &
the object of this invention is to reduce as far as possible the losses arising from the
friction between the chain & sprockets in ordinary chain gearing at the points
where the chain arrives at & leaves the chain wheel or its equivalent.
Now the means I employ to attain this end are as follows:
In one case I so arrange a sprocket wheel rotating on suitable bearings, &
to which the driving power is to be applied or received (which sprocket wheel
has teeth of a suitable length), that it is surrounded by the rim or a portion of
the rim of another wheel, which may have flanges to retain the chain if desired &
which is arranged to rotate on suitable bearings eccentric to the axis of the sprocket
wheel & in such relation as regards position & the amount of eccentricity of the
said wheel to the sprocket wheel, that the teeth on the sprocket wheel may project
through suitable openings made in the rim of the flanged wheels so that the sprocket
wheel teeth may be enabled to engage with the chain which passes round a portion
of the periphery of the flanged wheel. It will be seen that by this arrangement
provided the are of contact of the chain with the flanged wheel embraces & is
greater than the arc on the same wheel during which the teeth of the internal
sprocket wheel project through the openings in the rim of the flanged wheel, that the
teeth of the sprocket wheel will both enter & leave the chain whilst the chain is
supported by the rim of the flanged wheel, & not as in ordinary chain & sprocket
wheel driving, enter & leave in the portion of the chain intermediate between the
rims of the driver & driven wheels.
In another form of my invention I reverse the arrangements of the wheels in so
far as applying or receiving the driving power is concerned, whereas in the former
case the power is applied to, or received by the sprocket wheel directly, in this form
I apply the power, or receive it by the flanged wheel, the sprocket wheel in this
instance running freely inside the flanged wheel, & the sprockets themselves
transmitting or receiving the power, which is delivered to them by, or by them to or
from the links of the chain to or from the rim of the flanged wheel, by means of the
contact of the sprockets with the ends of the openings in the said flanged wheel,
through which such sprockets project the sprockets & openings being suitably shaped
so that the sprockets abut against the edges of the openings.
In some instances I prefer to use a flanged wheel carrying the chain in conjunction
with a sprocket wheel placed with its axis outside the periphery of the said flanged
wheel, the teeth of the said sprocket wheel being so shaped, & the wheel so arranged
that the teeth on the sprocket wheel enter the links of the chain & also enter holes
or recesses of suitable shape formed in the rim of the said flanged wheels.

page_text: In this case either the sprocket wheel or the flanged wheel may drive or be driven
as may be found most convenient, but I prefer to cause the flanged wheel to drive or
be driven, the sprocket wheel simply acting through the medium of its teeth to
transmit the power to, or from the chain to the flanged wheel, as the case
may be.
In order to obviate the use of two wheels, I also so construct the sprocket wheels
that the the teeth or sprockets are capable of motion in a radial direction whilst
revolving with the wheel, such motion being so predetermined that the sprockets
only enter or leave the links of the chain whilst the said chain is resting upon the
periphery of the wheel.
having as many radial grooves or recesses as there are required to be sprockets;
in each groove, & capable of movement to & fro in a radial direction, being placed a
bar arranged to fit the said groove & being shaped at one end to form the sprocket
to fit into the chain, & at the other having a suitably shaped projection or recess,
running in or on a fixed cam, which may be circular, & placed eccentrically to
the axis of the wheel, & which cam may consist of a grooved plate in the case
of projections on the sprocket bars being used or vice versa, or other equivalent
device to obtain the required insertion & withdrawal of the sprockets during the
revolution of the chain wheel.
One way inay obtain this result, is to arrange a wheel
I may also if desired make use of rollers or their equivalent arranged either on thé
sprockets or the flanged wheels in combination with the before mentioned devices,
so as to minimise the friction of the sprockets with the chain or the flanged
wheels.
FRANK BRYAN 87 Wellesley Road, Gunnersbury, W. 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 relates to improvements in the means for transmitting power by
rotary motion through the medium of chains and chain wheel gearing or the like, &
the object of this invention is to reduce as far as possible the losses arising from
friction between the chain & sprockets in ordinary chain gearing at the points
where the chain arrives at and leaves the chain wheel or its equivalent. Now
the means I employ to attain this end are as follows :-
Referring to the drawings. Fig 1 represents an arrangement of chain gearing in
which a sprockett wheel g mounted on an axis s (which may drive or be required to
be driven according to the purpose to which the gearing may be put), is surrounded
by the rim of a wheel ƒ which carries the chain c, and may if desired, be
provided with flanges to assist in retaining the chain in position. The wheel f is
mounted on an axis s¹ which is eccentric to the axis 8 of the wheel g. The
wheel has a series of openings (as shown at o in Fig. 5 which is a section of
the rim of the wheel f) to allow the sprockets on the wheel g to pass through in
order to engage with the links of the chain c passing round the periphery of
the wheel f.
By suitably proportioning the relative sizes of the wheels and the amount of
eccentricity of the two axes, it can be so arranged that the sprockets of the wheel g
project through the openings in the wheel ƒ at a portion of its periphery only,

page_text: and as found desirable this may be in that portion of the rim of the wheel ƒ upon
which the chain c is in firm contact & not at the points at which the chain is entering
upon or leaving the periphery of the wheel f. In this case the sprocket wheel g
receives or transmits the power. directly from or to the chain the wheel merely
acting as a carrier for the chain. If desired, the wheel f may itself receive or transmit
the power, in which case the sprockets will either impel or be impelled by the
extremities of the openings in the wheel f, in which case it is advantageous to use
rollers or the like to reduce friction between the sprockets & the wheel ƒ as shown
in Fig. 4, in which g is a portion of the sprocket wheel, the teeth of which rub
against the rollers carried by the wheel f.
Another method I adopt is to have the sprocket wheel g entirely outside the wheel f
as shown in Fig. 2, the teeth of the sprocket wheel being sufficiently long and the
distance of the wheels apart such that the said teeth pass right through the chain
and into the openings in the wheel which may then drive or be driven by the
chain c, through the intervention of the said sprockets. If desired the sprocket
wheel may in this case be the driver or driven wheel, when it will not be necessary
to provide openings in the rim off for the teeth of the wheel g to enter into.
A further means of obtaining the same end, is to make the sprocket wheel teeth
movable in a direction to and from the centre of the sprocket wheel, whilst revolving
with the wheel, and this may be done by an arrangement as shown in Fig. 3 in which
a wheel w is provided with a series of radial slots or grooves qq, in which slide bars
p, having the ends near the circumference of the wheel suitably shaped to act as
sprockets, & fitted with pins & roller or other suitable devices at the other end
running in or on a slotted cam g or the like, so shaped & fixed as to cause the
sprockets p to alternately project beyond & retire level or nearly level with or below
the periphery of the wheel w.
In all these applications, rollers or the like may be used on the wheel or sprockets
in order to still further assist in diminishing friction.
By varying the direction of the line joining the centre of the wheel in the cases as
shown in Figs. 1 & 2, relatively to the direction in which the chain is led on & off
the wheel, it will be seen that the teeth of the sprocket wheel may be made to gear
with the chain in other portions than those herein shown as may be found
desirable.
Thus the chain could be made to gear with the sprockets immediately on coming
into contact with the wheels or just before leaving the periphery as may best suit
any particular application.
Having now particularly described & ascertained the nature of my said invention,
& in what manner the same is to be performed, I declare that what I
claim is:-
1. In a system of chain gearing a wheel arranged with its axis eccentric to
that of a sprocket wheel or the like the rim of which wheel surrounds the periphery
of the sprocket wheel and has openings to allow of the sprockets in the sprocket
wheel passing through and engaging with the chain, substantially as illustrated and
described.
2. In a system of chain gearing, a plain or flanged wheel or the like carrying a
chain & having openings in its periphery to allow of the insertion of the teeth of a
sprocket wheel which sprocket wheel may be arranged either internally or external
to the rim of the said wheel, substantially as illustrated and described.
3. In a system of chain gearing, a plain or flanged wheel or the like carrying a
chain but having no openings in its periphery for the teeth of the sprocket wheel
which drives or is driven by the chain & is external to the said wheel substantially
as illustrated and described.
4. In a system of chain gearing, the use of a wheel having radially movable
sprockets or teeth & a cam or the like suitably arranged for controlling such motion,
substantially as illustrated and described.
5. In a system of chain gearing as herein set forth, the use of rollers or the like

page_text: for reducing friction between the sprockets & the other portions of the gearing
substantially as illustrated and described.
6. The particular combinations of the various parts as and for the purposes set
forth herein with reference to Figs. 1. 2. 3. 4 & 5 respectively.