Improvements in Variable Speed Gear, applicable to Velocipedes, Motor Cars, or to other Vehicles or Machines.
Year: 1896

page_text: Improvements in Variable Speed Gear, applicable to Velocipedes,
Motor Cars, or to other Vehicles or Machines.
I, DAVID JOY of 17 Victoria Street in the City of Westminster, Engineer, do
hereby declare the nature of this invention to be as follows:-
My invention has for its object to provide a variable gear for velocipedes, motor
cars or other vehicles or machines, requiring the employment of a varied gear for
example sewing machines and the like.
According to my invention I make either the driven wheel or the driver wheel
or both of them capable of being expanded radially that is in the direction of
their diameter.
I effect this by making the periphery of such wheels capable of expansion and
within this is a chamber into which fluid under pressure can be introduced so as to
cause the expansion of the said chamber.
This chamber may for example be a shell of india rubber or like elastic material
fastened at its centre to the shaft, or to a boss thereon, the shaft being made
hollow, and into it, and thence into the said chamber or elastic shell, is forced, air,
water, oil, or other fluid at a pressure such as to expand the said chamber or shell
and consequently the periphery of the wheel, so as to charge the relative propor-
tions of the gear wheels. Either or both of the wheels may be made thus variable
and when both are so made the one can be expanded and the other contracted by
passing the fluid from the one to the other.
A convenient method of making the expansible chamber is to form the wheel of
a belically arranged body or pipe with means for admitting the fluid under pressure
between the convolutions or into the pipe so as thereby to expand the wheel, or
the wheel may be made with a split periphery or periphery in parts with the
expansible chamber within it so that by expanding the chamber the periphery is
distended it returning to its normal smaller diameter when the fluid pressure is
relieved.
The charging with the fluid may be effected for example by employing the
small pump usually carried by machines with pneumatic tyres, or by providing a
pump for the purpose whit may be attached to and worked by the machine.
The driven band passing over the wheels may be in the form of a pipe and be
charged with fluid under pressure to vary its tension.
Dated this 28th day of Mor 1806
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.

page_text: Improvements in Variable Speed Gear, applicable to Velocipedes,
Motor Cars, or other Vehicles or Machines.
I DAVID JOY late of 17 Victoria Street in the City of Westminster
Engineer now removed to 85 Gracechurch Street in the City of London 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:-
My invention has for its object to provide a variable gear for velocipedes, motor
cars or other vehicles or machines, requiring the employment of a varied gear, for
example sewing machines and the like.
According to my invention I make either the driven wheel or the driver wheel
or both of them capable of being expanded radially, that is in the direction of
their diameter.
I effect this by making the periphery of such wheels capable of expansion and
within this is a chamber into which fluid under pressure can be introduced so as to
cause the expansion of the said chamber.
This chamber may for example be a shell of indian rubber, or like elastic material
fastened at its centre to the shaft or to a boss thereon, the shaft being made hollow,
and into it, and thence into the said chamber, or elastic shell, is forced air, water,
oil or other fluid at a pressure such as to expand the said chamber or shell and
consequently the periphery of the wheel so as to give the relative proportions to
the gear wheels. Either or both of the wheels may be made thus variable, and when
both are so made, the one can be expanded, and the other contracted by passing
the fluid from the one to the other.
A convenient method of making the expansible chamber, is to form the wheel of
a helically arranged body or pipe with means for admitting the fluid under pressure
between the convolutions or into the pipe, so as thereby to expand the wheel, or
the wheel may be made with a split periphery or periphery in parts, with the
expansible chamber within it, so that by expanding the chamber the periphery is
distended, it returning to its normal or smaller diameter when the fluid pressure is
released.
The charging with the fluid may be effected for example by employing the small
pump usually carried by machines with pneumatic tyres, or by providing a pump
for the purpose which may be attached to and worked by the machine.
The driving band passing over the wheels may be in the form of a pipe, and be
charged with fluid under pressure to vary its tension.
And in order that my invention may be well understood, I will describe with
reference to the accompanying drawings the means in which it may most easily
and satisfactorily be performed.
In each of the figures the same letters refer to similar parts.
In Fig. 1 & Fig. 2 is shown one of the gear wheels for a bicycle, constructed in
the method already described. P is the periphery of the wheel capable of
expansion, and may be formed either of an outer shell of steel or brass S or
entirely of elastic material as shown; such as indian rubber, as is shown in the
drawing. CCC are expansion chambers each connected with the central source
of pressure, and the whole fastened securely to the boss or shaft of the wheel, but
left to expand radially in the directions of the arrows,
of the internal pressure.
from the effect
The inside of the wheel is divided as shown into
several compartments of a somewhat spiral form, but forming together a circle,

page_text: which expands radially and which from its peculiar structure, in expanding will
raise projections J. J. on the surface of its periphery, between the divisions of the
compartments, these will serve as points of attachment for the driving band D,
which being also formed hollow, and filled with fluid at a pressure, will tend to
conform to the elevations in the periphery and so clinging to it to afford the driving
power adhesion.
Both the wheel itself, and the ordinary driving band though formed of indian
rubber or like elastic material, will have worked or moulded into them some fibrous
material, or cords in the direction of the strains they have to bear, to give them
the requisite hardness and strength, see M. M.
To provide fluid pressure, one of the most convenient of the tubes forming the
frame of the machine, say T in figure, may be fitted up as a pump, or a special
pump may be provided and suitably paced to be worked while the machine is being
ridden. If wished the fluid may be rendered somewhat plastic to reduce its
tendency to leakage.
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,
1st. The employment in velocipedes, motor cars, or other vehicles or machines,
requiring the employment of variable gear, gear-wheels capable of expansion or
contraction radially by the introduction of fluid pressure into their centres, or its
withdrawal therefrom.
2nd. The employment in such cases of the ordinary pump provided with the
velocipede or other such machine, for the purpose of producing such pressure.
February 25th 1897.
DAVID JOY,
85 Gracechurch Street, London.