Improvements in Speed-changing Mechanism.
Year: 1899

page_text: Date of Application, 25th Apr., 1899-Accepted, 2nd June, 1899
COMPLETE SPECIFICATION.
Improvements in Speed-changing Mechanism.
I, PHILIP LAWLEY, of Perseverance Cottage, Clapham, Beds., Mechanic, 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 the construction of mechanism by means of which the
speed of a revolving shaft may be altered from one to another of two or more
different speeds, without causing a stoppage of the revolution of the shaft.
Several methods are in use for effecting this result and some of them depend as
does my apparatus upon the use of friction driving a clutch, but up to the present
so far as I am aware no completely satisfactory apparatus has been devised; either
they are complicated and soon get out of order, or they are costly to construct,
noisy, and unreliable. Moreover few of the present methods are adaptable to more
than two speeds. The difficulty has been that when toothed gearing is employed
it is usually very noisy, and the teeth are liable to be broken by sudden shocks,
which are of frequent occurence in motor cars and such like vehicles which offer
perhaps the largest field for the employment of speed-changing mechanisms; fur-
ther the forms of friction mechanism hitherto in use for this purpose do not lend
themselves readily to a compact and sightly construction especially if more than
two speeds are required.
Now the object of my invention is to construct an apparatus that is neat and
reliable, equally adaptable to two, three or even more speeds, and of such a simple
nature that it cannot readily get out of order, and which at the same time can be
constructed at a moderate cost.
My invention consists in employing a number of loose cylindrical sleeves one
within the other and each divided into two parts longitudinally at its centre;
one half of each sleeve is attached to a central spindle in such a manner that it
must revolve with it, though free to move a short distance longitudinally, while
the other half of the sleeve can revolve round the central spindle but cannot move
longitudinally with respect to it.
or
same
By means of a clutch mechanism at the central division of the sleeves I arrange
that any pair of the series may be in action at a given time, and as each pair
to the central spindle,
represents a different speed communicated
communicated by the central spindle to one of three pulleys connected
to the loose halves, of different diameter but running at the
speed, I thus obtain a choice of speeds according to the number of sleeves employed.
According to one construction I arrange a series of say three sleeves working
one within the other and concentrically with regard to a spindle fitting into the
smallest sleeve. One half of each of these sleeves is free to revolve on the spindle
or on one of the other sleeves between it and the spindle; the central spindle and
each of these said halves is provided with two collars fixed to and revolving with it,
the outer collar of each pair being preferably provided with a ball bearing in order
to reduce the friction of the end thrust to a minimum. The other half of each

page_text: sleeve is connected to the central spindle by means of keys or feathers on the
spindle and on the two inner sleeves, in such a manner that unless stopped alto-
gether, each sleeve must always revolve with, and at the same speed as the central
spindle, though each can slide a short distance longitudinally with respect to the
central spindle, and with respect to each other. These latter I will call the driving
halves, assuming that the spindle is transmitting power from itself to another
revolving spindle, while the afore mentioned halves will then be the driven por-
tions. The driven halves are each provided at their outer end with a suitable
pulley or spur wheel of a diameter proportionate to the speed it is required to
transmit, and its inner end is recessed of a conical shape and at such an angle
as accurately to fit a conical projection formed on the end of the corresponding
half of each driving sleeve. When therefore the conical projection of the driving
half is caused to press in a longitudinal direction against the conical recess of the
driven half, the friction between them will cause the driven half to revolve at the
same speed as the driver i.e. at the same speed as the central spindle.
By means of circular recesses in the outer ends of the driving sleeves and suit-
able levers or screws, I can put any one of the three into gear with its opposite
half, and thus revolve the particular pulley or wheel required.
If necessary I may alter the shape of the faces at the centre, in order to obtain
a larger surface in frictional contact, and so transmit a larger power. It must
also be understood that though primarily intended for use on motor-cars, cycles;
and such like vehicles, in which it is important that the change of speed shall
be made without stoppage of the driving mechanism, my invention is also appli-
cable to fixed motors or machinery, and in such cases instead of the driving and
driven halves of the sleeves being connected together by a clutch depending upon
friction, I may connect them by means of a claw coupling, which is formed by a
series of lugs on the one half being pressed into corresponding recesses on the
other half. In this way practically all the end thrust on the collars above men-
tioned is obviated, with a consequent saving in power. Unless however but small
powers are being transmitted it is necessary in this case to stop the mechanism at
each change of speed, on account of the shock which would otherwise probably
occur on thrusting the claw coupling into gear.
On the accompanying drawings in which the same letters refer to like parts
in all the views:-
Fig. 1, is a longitudinal section of a three speed mechanism.
Fig. 2 is a section through the line CD, and Fig. 3, is a section through the
line A B.
2
Referring first to Fig. 1, ₁, fif₂ and 9, are a series of cylindrical sleeves
fitted one within the other, and is a cylindrical shaft fitting the inside of the
smallest pair of sleeves e₁ eq.
The series of halvas e, f, J. are free to revolve about the central shaft h, c
working on the shaft itself, f working on 2, and working on f₂. They are
prevented from moving longitudinally on the shaft by means of the three collars a,
79, at the centre, and by the three outer collars l, m, and n, of which is fixed to
the shaft, m is fixed to the boss of the chain wheel k, which in its turn is fixed to,
and revolves with the sleeve c₂, while the third collar is fixed to the boss of the
chain wheel which is fixed to the sleeve f₂ and revolves with it. Each of these
outer collars is fitted with a ball bearing in order to reduce the friction caused by
the end thrust when the coned parts at the centre are in gear.
The sleeves e, f, g, are connected to the central shaft by means of the feathers
shown at u, and win Fig. 2, so that they must always revolve with, and at the
same speed as the shaft h, but so that the sleeva e, can slide lengthwise on the
shaft h, f, can slide on ₁, and on f₁. This movement lengthways is controlled
by levers fitting in the recesses r, y, z, and fixed to the framework of the apparatus.
When a fast speed is required the conical part of the sleeve g, is pressed into
the conical recess in its opposite half g, until the friction is sufficient to cause them
to revolve together; the shaft is thus connected to the chain wheel i, which is

page_text: caused to revolve. If a slower speed is required the wheel j is connected to the
shaft by pressing sleeve f₁ into gear and if a still slower one is required, for in-
stance in the case of a motor-car mounting a hill, the small wheel is brought
into connection with the shaft by sliding e, into gear. It must be understood that
only one of these pairs of sleeves must be in gear at the same time and if chains
are employed for transmitting the power there will be a chain to each of the
wheels i, j, k, and a corresponding wheel on the drivem shaft. I do not however
confine my invention to chain driving, as pulleys with belts may equally well be
employed, or toothed spur wheels in direct connection may be attached to the
sleeves.
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 speed changing mechanism the combination with a series of two, three,
or more pairs of sleeves, working one within the other and connected at their
centre by a clutch, of means for causing one half of each pair to revolve with, and
at the same speed as a central spindle while the other half of each pair is free to
revolve around the same spindle substantially as described herein.
2. In a speed changing mechanism the combination with a series of two, three,
or more pairs of sleeves connected by a friction clutch, and a series of feathers
connecting one half of each pair to a central revolving spindle, of a series of collars
provided with ball bearings substantially as described herein and for the purpose
specified.
3. In a speed changing mechanism the combination with a series of two, three,
or more pairs of sleeves connected by a loose coupling, and a series of feathers
connecting one half of each pair to a central revolving spindle, of a series of collars
provided with ball bearings substantially as described herein and for the purpose
specified.
ו.
6311 1
1800
SYDNEY E. PAGE, A.M.I.C.E.,
18, New Bridge Street, London, E.C., Agent for the Applicant.