Improvements in Variable Speed Gear for Velocipedes or Motor-cars, applicable to other purposes.
Year: 1897

page_text: PROVISIONAL SPECIFICATION.
Improvements in Variable Speed Gear for Velocipedes or Motor-cars,
applicable to other purposes.
I, GEORGE KIRBY, Junior, of 50, Myddleton Road, Bowes Park, London, N.,
Wall-paper Manufacturer, do hereby declare the nature of this invention to be as
follows:-
This invention relates to what is known as differential or variable speed gear
for velocipedes or for other purposes such for instance as motor-cars, lathes, etc.,
and for the sake of example I will describe my invention as applied to a bicycle
with chain-driving gear as follows:-
On the ordinary or any suitable crank driving spindle or axle I arrange and
mount the chain-driving sprocket wheel on ball or other suitable bearings or in
other suitable manner so that same is free to revolve upon or rotate with respect
to said crank spindle or axle and this chain wheel has an internal ring of teeth,
i.e. is an internally toothed wheel.
Alongside of this sprocket wheel and concentric therewith I mount upon said
crank axle a gear wheel of suitable diameter (according to the variation in speed
desired) but always considerably smaller than the aforesaid chain wheel and this
gear wheel is adapted to slide (upon a feather or otherwise) upon said crank axle
or spindle towards and away from said chain wheel while said gear wheel is
revolved with and by said crank axle without which latter it cannot revolve by
itself and I provide any suitable forked arm or other device adapted for the pur-
pose to slide said gear wheel to and fro along said axle-a stud or studs or crank
pin or other suitable device being provided on or operated by said gear wheel to
engage or lock the said gear wheel to said chain wheel when the former is forced
in one direction along the axle and to release or disengage said gear wheel from
said chain wheel when moved in the opposite direction-thus when said gear
and said chain wheel are forced or locked together as aforesaid thereby the chain
wheel is caused to revolve equally with the crank axle or spindle .e. without
variation of speed.
i
In order to vary the speed I use the following mechanism or means according to
my present invention:-
Attached to or near the bottom bracket or other suitable part of the frame of
the bicycle I arrange and mount a suitable fixed support on which is carried a
rocking bar or device adapted to rock on a pivot or otherwise adapted to oscillate
or otherwise reciprocate (for instance same may slide if desired instead of oscillat-
ing) and this device which for the sake of example I will term the "rocker"
carries a suitable train of wheels thereon advantageously two idle toothed wheels
in gear with one another and adapted when rocked in one direction to gear one with
the aforesaid gear wheel on the crank axle and the other with the aforesaid internal
ring of teeth on the chain wheel whereby motion is transmitted from the said gear
wheel on the crank axle (which has first however been disengaged or unlocked
from its aforesaid direct connection with the chain wheel) to the internal ring of

page_text: teeth on said chain wheel through the aforesaid intermediate gear wheels on the
rocker" and thus the chain wheel is caused to revolve at a speed slower than the
cranks or driving axle and consequently the speed is reduced; while by rocking
or moving the said intermediate gear wheels out of gear which rocking movement
(of the "rocker") may be effected by any suitable lever or mechanism operated
from any convenient part of the machine and advantageously at the same time and
by the same lever or connected mechanism moving the aforesaid gear wheel on the
axle into direct engagement with the chain wheel again thereby the full speed is
again obtained.
In applying my present invention to motor-cars or to lathes or to other purposes
any alterations necessary for adapting same to such purposes will be easily under-
stood and readily effected.
applicable to other purposes.
I, GEORGE KIRBY, Junior, of 50, Myddleton Road, Bowes Park. London, N.,
Wall-paper Manufacturer, do hereby declare the nature of this invention and in
what manner the same is to be performed to be particularly described and ascer-
tained in and by the following statement:-
-
This invention relates to what is known as differential or variable speed gear
for velocipedes or for other purposes such for instance as motor-cars, lathes, etc.,
and for the sake of example I will describe my invention as applied to a bicycle
with chain-driving gear as follows:-
-
On the ordinary or any suitable crank driving spindle or axle 1 arrange and
mount the chain-driving sprocket wheel on ball or other suitable bearings or in
other suitable manner so that same is free to revolve upon and with respect
to said crank spindle or axle and this chain wheel has an internal ring of teeth,
i.e., is an internally toothed wheel.
Alongside of this sprocket wheel and concentric therewith I mount upon said
crank axle a gear wheel of suitable diameter (according to the variation in speed
desired) but always considerably smaller than the aforesaid chain wheel and this
gear wheel is adapted to slide (upon a feather or otherwise) upon said crank axle
or spindle towards and away from said chain wheel while said gear wheel is always
revolved with and by said crank axle without which latter it cannot revolve by
itself and I provide any suitable forked arm or other device adapted to be moved
to and fro laterally in order to slide said gear wheel to and fro along said axle-a
stud or studs or crank pin or other suitable device being provided on or operated
by said gear wheel to engage or lock the said gear wheel to or into said chain
wheel when the former is forced in one direction along the axle and to release or
disengage said gear wheel from said chain wheel when said gear wheel is moved in
the opposite direction thus when said gear and said chain wheel are forced or locked
together as aforesaid thereby the chain wheel is caused to revolve equally with the
crank axle or spindle i.e. without reduction of speed.
In order to vary the speed I use the following mechanism or means according to
my present invention:-
Attached to or near the bottom bracket or other suitable part of the frame of

page_text: the bicycle I arrange and mount a suitable fixed support on which is carried a
rocking bar or device adapted to rock on a pivot or otherwise adapted to oscillato
or otherwise reciprocate (for instance same may slide if desired instead of oscillat-
ing) and this device, which for the sake of brevity I will term the "rocker," carries
a suitable train of wheels thereon (for instance I will describe two such idle toothed
wheels) in gear with one another and one of said idle wheels is adapted when rocked
in one direction to gear with the aforesaid gear wheel on the crank axle and the
other said idle wheel is adapted to gear with the aforesaid internal ring of teeth
on the chain wheel whereby motion is transmitted from the said gear wheel on the
crank axle (which has first however been totally disengaged or unlocked from its
aforesaid direct connection with the chain wheel) to the internal ring of teeth on
said chain wheel through the aforesaid intermediate gear wheels on the "rocker"
and thus the chain wheel is caused to revolve at a speed slower than the revolution
of the cranks or driving axle and consequently the speed is reduced while by rock-
ing or moving the said intermediate gear wheels out of gear which rocking
movement (of the "rocker") may be effected by any suitable lever or mechanism
operated from any convenient part of the machine and advantageously at the same
time and by the same lever or connected mechanism moving the aforesaid gear
wheel on the axle into direct engagement with the chain wheel again and thereby
the full speed is again obtained.
Referring to the accompanying drawings:
--
Fig. 1 is a local side view in elevation showing variable speed gear at full gear,
and
Fig. 2 is edge view thereof looking in the direction of the arrow 1 Fig. 1.
Fig. 3 is corresponding view to Fig. 1 showing the gear at low gear, and
Fig. 4 is edge view of Fig. 3 looking in the direction of the arrow 2 Fig. 3
Fig. 5 is detail view of the changing gear removed from the other part of the
mechanism.
a is the driving spindle or axle.
b is the chain driving sprocket wheel loosely mounted on the axle a so as to be
free to revolve thereon.
c is an internal ring of teeth.
d are the external sprocket or chain driving teeth.
e is gear wheel mounted on a feather on the axle a and concentric with the
sprocket wheel d but considerably smaller than the latter.
e is crank pin or stud projecting from the gear wheel e on the side proximate
to the driving wheel b.
el is a collar fixed to the gear wheel e a fork f pivotted at f¹ being adapted to
engage with said collar el whereby the latter together with the gear wheel o can be
moved laterally along the axle a (on a spline or feather) so that such gear wheel e
and collar e thereon and the axle a must always revolve together.
J
The crank pin or stud et projects into engagement between the spokes of the
sprocket wheel b so that when said gear wheel is by means of the fork f forced
towards the sprocket wheel b thereby the stud e* will enter between two of the
spokes of the sprocket wheel 6 (as shown in Figs. 1 and 2) and thereby the sprocket
wheel b is revolved at the same speed as and with the crank axle a.
g and h are two intermediate gear wheels mounted on a swivel plate i swivelled
or pivotted to the support which latter is fixed to the frame tubes z of the cycle
or other machine to which said differential gear is applied.
To this swivel plate i a driving or connecting rod m is attached this connecting
rod being operated from any convenient point on the cycle or other machine.
n is a connecting rod pivotted at * to the crank end f* of the aforesaid forked
device f so that by raising or lowering the connecting rod n thereby the fork f is
moved laterally with respect to the crank axle a to thus force the stud e* on the
gear wheel e into engagement with the sprocket wheel b while by simultaneously
operating the rod m thereby the gear wheels and h are moved into mid-position
as shown in Figs. 1 and 2 that is to say are moved out of engagement with either

page_text: the gear wheel e or the internal ring of teeth c while by moving the operating rod n
in the opposite direction thereby the stud e¹ on the gear wheel e is moved out of
engagement with the sprocket wheel b so that b and e are entirely free of one
another while at same time the rod m is operated so as to oscillate the swivelled
plate and thereby move the intermediate gear wheel g into gear with the gear
wheel e while the other intermediate gear wheel h is thereby moved into gear with
the internal ring of teeth c as shown in Figs. 3 and 4 (this latter gear wheel h
being made broader than the other intermediate gear wheel g so as to extend into
the same plane as the internal ring of teeth c and in this position the rotation of
the crank axle a will be transmitted through the gear wheels e g and h to the
internal ring of teeth c on the sprocket wheel b whereby the latter will revolve at
a much slower speed than the axle a and thereby the speed is reduced.
The connecting rods m and n should be so connected to any suitable operating
mechanism (not shown) that said rods are operated simultaneously or in suchwise
that the stud e* on the gear wheel e is moved clear of the sprocket wheel b before
the intermediate wheels and h are put into gear with the gear wheel e and
internal teeth c as aforesaid and vice-versa.
xx are the cranks on the crank axle a.
In applying my present invention to motor-cars or to lathes or to other purposes
any alterations necessary for adapting same to such purposes will be easily under-
stood and can readily be effected by any competent mechanician and need not
therefore be further described here.
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. In variable speed gear for the purposes, specified having a sprocket wheel
loosely mounted on the driving axle and provided with an internal ring of teeth-
the arrangement and combination therewith of a gear wheel (of smaller diameter
than the diameter of said internal ring of teeth) also mounted on said driving
axle so as to be always revolved by the latter and adapted to be moved laterally
thereon towards and away from said sprocket wheel, means provided on said gear
wheel to lock same to said sprocket wheel when moved into engagement therewith,
a "rocker" mounted to a fixed support, two (or more) idle wheels carried on said
rocker in gear with one another and adapted to be moved into such position that
one said idle wheel will mesh with the aforesaid internal ring of teeth while the
other said idle wheel will mesh with the aforesaid small gear wheel after the latter
has been first disengaged from said sprocket wheel, and means to slide said gear
wheel into locked engagement with said sprocket wheel and simultaneously
actuate said "rocker' so as to move said idle wheels out of engagement with said
gear wheel and said internal ring of teeth said means being also adapted to move
the said idle wheels into mesh with the said sprocket and gear wheels after first
totally disengaging the latter, substantially as and for the purposes described.
2. The improved variable speed gear constructed combined and arranged to act
substantially as and for the purposes set forth.
"
Dated this 17th day of March 1898.
TONGUE & BIRKBECK,
Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.