An Improved Variable Gear with Automatic Clutch Action for Cycles.
Year: 1894

page_text: PROVISIONAL SPECIFICATION.
An Improved Variable Gear with Automatic Clutch Action
for Cycles.
We ALEXANDER MUNRO Coachbuilder 7 Walket Street Glasgow, and JOHN
MILLS Engineer, 60 Dunaid Street Glasgow, do hereby declare the nature of this
invention to be as follows :-
--
This invention relates to cycles and it has for its object to provide them with
driving gear that can be readily changed or converted."
An automatic clutch action is provided in connection with the gear.
In carrying out our invention we fit on the ordinary stationary axle of the
driving wheel of the cycle, an outer concentric tubular axle having the chain wheel
fitted on it at one end and, preferably, thi ce bosses distributed round the outer
circumference, which is enlarged or made of an increased diameter of its other end
Fitted in each of these bosses is a pivot oi stud on which is mounted a bevel
pinion which gears with two bevel wheels located at each side. One of these bevel
wheels is fixed on or forms part of the hub of the driving wheel whilst the other is
mounted on the stationary axle. The pivots aro angled or inclined to light or left
according to the different sizes of bevel wheels used.
The driving wheel revolves on the external or tubular axle.
The bevel wheels are put into gear by means of a movable friction disc which
can be pressed against the bevel wheel fitted on the internal or stationary axle and
are thrown out of gear by merely releaving said disc.
An automatic clutch arrangement is located between the chain wheel and the
bub of the driving wheel This clutch arrangement consists of a cylindrical casing
or box fixed on or made one with the hub of the driving wheel and having two
interual ledges or stops formed or fitted in it Fitted in the inside of the box
are two semi-circular clutchs mounted loosely and movably upon two segments
opposite each other on the tubular axle The arrangement is such that when the
diving wheel is required to revolve at the same speed as the cham wheel the
forward end of each segment acting on a notch or iccess formed in the inside of
each of the clutches pushes them latterly so as to force one end of each of theu
into recesses formed in the box or casing and against the stops or ledges, thereby
causing the driving wheel to evolve along with the chain wheel When the
driving wheel is revolving faster than the chain wheel the clutches ship back and
release themselves automatically from then gup
The arrangement of the bevel gearing hereinbefore described enables an increased
spood of the driving wheel to be obtained.
All the revolving parts of the gear are preferably mounted in ball bearings.
Dated this 20th day of December 1894.

page_text: An Improved Variable Gear with Automatic Clutch Action
for Cycles.
We, ALEXANDER MUNRO, Coachbuilder, 7 Walker Street, Glasgow, and
JOHN MILLS, Engineer, 60 Dunard Street, Glasgow, 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 cycles and it has for its object to provide them with
duving gear that can be readily changed or converted.
An automatic clutch action is provided in connection with the gear.
And in order that our said invention may be properly understood we have
hereunto appended two explanatory sheets of drawings, whereon,
Fig. 1 is a side view of a bicycle.
Fig. 2 is a vertical section of the variable differential geai.
Fig. 3 15 a side view of the gear Fig. 2.
Fig. 4 is a sectional view of the clutch ss out of gear.
Fig. 5 is a sectional view of the clutch s s¹ in gear
Fig. 6 is a view of a modification.
Fig 7 is a view of a friction clutch
In carrying out our invention, as shown at Figs. 1, 2, 3, 4 and 5, we fit, on the
ordinary stationary axle a of the driving wheel of the cycle, an outer concentric
tubular axle having the chain wheel e fitted on or in connection with it at one
end, and, preferably, three bosses d distributed, at equal distances apart, round
the outer circumference, (which is enlarged or made of an increased diameter,)
of its other cud Fitted in each of these bosses is a pivot or stud e on which 18
mounted a bevel punon which gears with two bevel wheels g, h, located at each
side of the pious
The bevel wheel g is fixed on or forms part of the hub of
the diving wheel whilst the wheel is mounted on a collar on the stationary
axle a.
The pivots e are angled o inclined to right or left according to the
different sizes of bevel wheels used.
The driving wheel, of which are the spokes, revolves along with the wheel g
on the external or tubular axle b.
All the parts are, to reduce friction, made to run on ball bearings. I are
the balls, m the cones and n the cups
918 an enclosing ring or casing for excluding dust which may be made in two
parts secured together by lugs and screws and which is held in place by the
nuts e of the pivot studs e.
The bevel wheel is always in gear with the pinions, whilst the bevel wheel h
is put to gear with the pinions, whenever desired, by means of a movable friction
disc o, carried on an enlarged part of the axle a, which can be pressed against
the bevel wheel h and is thrown out of gear by merely relieving said disc.
The friction disc o cau be actuated in different ways one method beng shown
at Fig. 2 wherein the disc is provided with an internally screwed boss of which can
be turned on the screw thread a' made on the end of the axle a. The boss which
18 hexagonal externally is tuned by means of a level o' fitted theicon and which
Is actuated by a connecting 1od or wire os attached to the hand lever p (see
Fig 1) fulci umed to a bracket p₁ on the pillar of the cycle. By pulling or
pushing the hand lever the wire o is pulled or pushed so as to move the level o²
and turn the boss on the screw a' thereby moving the disc o against the wheel or
withdrawing it therefiom. The level is locked in position on the hexagonal
surface of the boss by the pinching screw of (see Fig. 3).
An automatic clutch arrangement is located between the chain wheel c and the

page_text: of the
Fitted
hub of the driving wheel. This clutch arrangement consists (see Figs. 4 and 5)
of a cylindrical casing or box fixed on or inade one with the hub
diving wheel and' having internal ratchet teeth or stops formed in it
in the inside of the box are two semi-circular clutches,, mounted loosely and
movably upon two segments t, tt, opposite each other, on the tubular axle b. Tho
arrangement is such that when the diving wheel is required to evolve at the
same speed as the chain wheel c the forward end of each segment acting on a
notch or recess u formed in the inside of each of the clutches pushes them laterally
so as to force one end of each of them into one of the recesses (see Fig. 5)
formed in the box or casing and against the stops or ledges r', thereby causing
the driving wheel to revolve along with the chain wheel Whon the driving wheel
is revolving faster than the cham wheel as when the high gear is put on (as
hereinafter described) or when going down hill the clutches slip back (see Fig. 4)
and release themselves automatically from their grip.
Under a modification, as shown in Fig. 6, instead of the friction disc o being
used a friction band to is employed. This band, which is shown in side view
at Fig. 7 to a reduced scale, fits into and extends almost completely round a
V groove h¹ made on the circumference of the wheel h. A bent lever 10¹ 15 pinned
to one end of the band and a bent level to to the other end. These lovers aie con-
nected together by the link 103. The wire o after being passed through a guide /*
18 attached (see also Fig. 1) to the lever a whilst a wire to connects the lever w³ to
a fixed stiap we on the fiame By pulling on pushing the hand lever p, as before,
the band to can be tightened sufficiently to lock the wheel h or slackened sufficiently
to allow it to revolve on the axle a
As shown also at Fig. 6 the clutch mechanism Figs. 4 and 5 can be dispensed
with and gearing used in lieu thereof The chain wheel c 1s fitted on and made
one with the circular dust cover which is held in place by pivot studs r
(preferably three) and nuts on the studs. These studs aro screwed into
bosses d' on the hollow axle b. Pinions are fitted loosely on the pivot-studs and
geal, on the one hand, with the wheel a' secmed rigidly to the hub, and, on the
other band, with a large pinion mounted on the axle a. This pinion 25 18
provided with a disc having a cucumferential V groove in which a band a³,
(similar in construction to the band to is fitted. The band is operated by means
of a second wire y (see Fig. 1) attached to the hand lever p above its fulcrum so
that when the band w is thrown out of gear the band is put into gear and vice
versa.
2
7
With the arrangement shown at Figs. 1 to 5 when the friction disc o 18 thrown
out of gear the chain wheel drives tho sprocket wheel c, which, by means of the
clutch s, s', is caused to directly drive the hub and the driving wheel, but when
the disc o is thrown into gear the wheel is locked and the sprocket wheel c by
means of the tubular axle b, pinions f, and bevel wheel g, is caused to indirectly drive
the bub and driving wheel at an increase of speed according to the gear of the
bevel wheels. We generally construct the mechanism so that, when the sprocket
wheel c duertly drives the hub through the clutch s, s', the gear is about, say, 44
but when the bevel gearing is thrown into action the gear is raised to, say, 109. It
will be readily seen that when the hub is revolving at a greater speed than the
sprocket wheel c and axle b, as when the high gear is put on or the machine is
running down hill, the automatic clutch s, & is thrown out of gear. In the modified
arrangement shown at Fig 6 the bevel gearing is such that when the friction
clutch is thrown into gear the machine tuns at about 57 gear but when the
fuction clutch w 18 thrown into gear the machine iuus at about 109
For some machines, especially aceis, we may do away with the low gear and
use the high gear alone so that the machine can always be driven at a high speed. In
this case the clutches would be done away with and the sprocket wheel c made to
drive the high gear duect, the wheel being keyed in position. Or the friction
clutch o or the band to could be used to throw the high gear into action whenever
required and, of course, in this latter case, whenever the friction clutch would be

page_text: thrown out of gear the sprocket wheel would'run free without turning the driving
wheel
We do not confine ourselves to any special speed gear, such as 44 and 109,or 57
and 109, as the speed gear can be varied to suit requirements.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what wo
consider novel and desire to claim is :-
1 A variable gear for cycles constructed and arranged substantially as heroin-
before described with reference to Figs. 1 to 5 of the diawings annexed.
2. The automatic clutch mechanism, substantially as hereinbefore described and
shown at Figs. 2, 4, and 5 of the drawings annexed.
3. The modified variable gear for cycles constructed and arranged substantially
as here before described with reference to Fig. 6 of the drawings annexed.
Dated this 20th day of September 1895.
H. D. FITZPATRICK,
70 Wellington Street, Glasgow, Agent