Improvements in or relating to Variable Speed Gears.
Year: 1898

page_text: Improvements in or relating to Variable Speed Gears.
I, JOHN JAMES HENRY STURMEY, of 19, Hertford Street, Coventry, Warwick-
shire, Journalist, do hereby declare the nature of this invention to be as
follows:-
-
My invention relates to variable speed gears and is especially applicable to
autocars though it may be applied to other machinery where such a device is
desirable.
In carrying out my invention I mount two or more compound wheels or pulleys
on a shaft. These compound wheels are constructed on the Crypto or other
well known system which provides variations in speed between the centre and
the periphery of the wheel when certain parts of the mechanism of the wheel are
locked and unlocked by a sliding bolt or the like which is operated from the
exterior of the wheel without entirely stopping the rotation of the said wheel.
To facilitate the further description of my invention I will suppose that I am
using two compound wheels each giving two speeds. I prefer to arrange the
speeds so that one wheel gives the extreme (or 1st and 4th) speeds, while the
other gives the intermediate (2nd and 3rd) speeds. Either wheel, one at a time,
may be caused to rotate with the shaft by being connected thereto by means of a
sliding or friction clutch operated by a forked lever or other suitable means.
change gear bolts of both wheels are operated together by one handle through
suitable connections. The driven shaft is connected to the compound wheels
either directly by two belts or chains or indirectly through an intermediate shait
and belt, chain or spur gearing.
The
Supposing the compound wheels to be set at their lower speeds respectively
and both free on the shaft, the device may be operated as follows. The fork lever
is moved to connect the wheel affording the extreme gears to the shaft; this
gives the lowest or 1st speed.
Then the fork lever is reversed to disconnect the
extreme gears wheel and connect the wheel affording the intermediate gears to
the shaft; this gives the 2nd speed. Next the handle is operated which moves
the bolts of both the compound wheels setting the said wheels at their higher
speeds; this gives the 3rd speed, the intermediate gears wheel being still con-
nected to the shaft. Finally the fork lever is again moved over, disconnecting
the intermediate gears wheel and connecting the extreme gears wheel to the
shaft; this gives the highest or 4th speed, this wheel having been changed to
its higher speed when the intermediate gears wheel was changed to its higher
speed. By reversing the handle which moves the change bolts of the compound
wheels, the gear will be returned to the first speed and the other compound wheel

page_text: prepared for the 2nd speed; and so on, though the gears are not necessarily
changed in the above order.
It will be readily understood that this invention can be developed, modified
and otherwise applied without exceeding its fair limits.
Dated this 4th day of January 1898.
G. DOUGLAS LEECHMAN,
18, Hertford Street, Coventry,
Chancery Lane, London, W.C., and
49, Middle Abbey Street, Dublin,
Patent Agent for the Applicant.
Clating to variable Speed Gears.
I, JOHN JAMES HENRY STURMEY, of 19, Hertford Street, Coventry, Warwick-
shire, Journalist, 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:-
..2..
My invention relates to variable speed gears and is especially applicable to
autocars though it may be applied to other machinery' where such a device is
desirable..
16
J
In carrying out my invention I mount one or more compound wheels or pulleys
on a shaft. These compound wheels are constructed on the Crypto" or 'other
'well-known system which provides variations in speed between the centre" and
the periphery of the wheel when certain parts of the mechanism of the wheel
are locked and unlocked by a sliding bolt or the like which is operated from the
exterior of the wheel without entirely stopping the rotation of the said wheel.
To facilitate the further description of my invention I will take the case shown
in the accompanying drawing where there are two compound wheels each giving
two speeds. I prefer to arrange the speeds so that one wheel (2) gives the
extreme (1st and 4th) speeds, while the other (3) gives the intermediate (2nd and
3rd) speeds. Either wheel, one at a time, may be caused to rotate with the
shaft 4 by being connected thereto by means of a sliding or friction clutch 5
operated by a forked lever 6 or other suitable means. The change gear bolts of
both wheels are operated together by one handle 10 through suitable connections
such as the rods 8 and cross bar 9. The handle 10 may be pivotted to the cross
bar 9 and carry a snail 11 which bears on the fixed bar 12. The parts are nor-
mally held in the position shown in full lines with the short radius of the snail
perpendicular to the bar 12 by the expansion springs 13 bearing against the
stops 14 on the rods 8 and against the guides 15 through which the said rods
pass at the ends of the bar 12. The bolts 7 are now in their inner positions.
turning the handle 10 over to the position shown in dotted lines the long radius
of the snail is brought perpendicular to the bar 12 and the rods are drawn further
through the guides 15 against the action of the springs 13. The bolts 7 are now
in their outer positions, and if the deeper end of the snail be worked off a little
so that the snail overbalances a little when brought into the dotted position the
-springs will hold the parts in this position also. The driven shaft is connected
to the compound wheels either directly by two belts or chains or indirectly
through an intermediate shaft and belt, chain or spur gearing, as desired.
By
Supposing the compound wheels 2, 3 to be set at their lower speeds respectively
and both free on the shaft, the device may be operated as follows. The fork

page_text: lever 6 is moved to connect the wheel 2 (affording the extreme gears) to the
shaft 4 this gives the lowest or 1st speed. Then the fork lever is moved to dis-
connect the extreme gears wheel 2 and connect the wheel 3 (affording the inter-
mediate gears) to the shaft; this gives the 2nd speed. Next the handle 10 is
operated so as to set the wheels 2, 3 at their higher speeds; this gives the third
speed, the intermediate gears wheel 3 being still connected to the shaft. Finally
the fork lever 6 is again moved over, disconnecting the intermediate gears
wheel 3 and connecting the extreme gears wheel 2 to the shaft; this gives the
highest or 4th speed, this wheel (2) having been changed to its higher speed
when the intermediate gears wheel (3) was changed to its higher speed. By
reversing the handle 10 the gear will be returned to the 1st speed and the
other compound wheel prepared for the 2nd speed; and so on, though the gears
are not necessarily changed in the above order.
The fork lever 6 may be provided with a spring-actuated finger 17 adapted to
engage in a rack 18 having three notches or teeth. When the lever is moved
over to either side the clutch 5 engages with the opposite compound wheel and
the finger holds the lever there. In the illustration the lever is shown as held
in its intermediate position, the clutch 5 being clear of both compound wheels
which are consequently both loose on the shaft and no power can be transmitted
through them.
It will be readily understood that this invention can be developed, modified
and otherwise applied without exceeding its fair limits.
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 a variable speed gear, the combination of two or more compound wheels
or pulleys mounted on a shaft and adapted to be secured thereto one at a time
by the operation of a single lever so that the securing of one wheel or pulley to
the shaft is preceded automatically by the release of the other or others there-
from; and means for simultaneously operating the change gear bolts of the said
wheels or pulleys through suitable connections by moving a single handle.
2. A variable speed gear constructed, arranged and adapted to operate sub-
stantially as herein described and illustrated.
Dated this 4th day of October 1898.