Automatic Air Pumps for Pneumatic Tyres for Bicycles and other Vehicle Wheels.
Year: 1896

page_text: Date of Application, 20th Nov., 1896-Accepted, 18th Sept., 1897
COMPLETE SPECIFICATION.
Automatic Air Pumps for Pneumatic Tyres for Bicycles and other
Vehicle Wheels.
We, JANES HARRY KEIGHLY MCCOLLUM, of 1001 Bathurst Street, Electrician,
and REMIGIUS ELMSLEY, of 35 Adelaide Street, East, Esquire, both of the City of
Toronto, in the County of York, in the Province of Ontario, Canada, do hereby
declare the nature of this invention, and in what manuer the same is to be per-
formed to be particularly described and ascertained in and by the following
statement:-
Our invention relates to improvements in Automatic Pumps for Pneumatic
Tyres of bicycle and other vehicle wheels and the object of the invention is to
design a very simple form of pump, which may be operated to pump up the air
tube of the tyre automatically to any desired pressure should any air escape and
keep it pumped up as the wheel rotates and it consists essentially of a tubular or
other suitably formed passage-way, which is preferably located within the tyre
and extends preferably around the major portion thereof, is connected at one end
to the ordinary air valve, which communicates with the interior of the air tube
and at the other end to the atmosphere and is so arranged that continued depres-
sion of the tyre on the ground as the wheel rotates forces the air in the tubular
passage-way from the open end along the tube through the valve into the air
tube by compressing it continuously as the wheel rotates as hereinafter more
particularly explained.
Fig. 1, is a side view of a wheel rim and tyre showing in dotted position the
preferable location of the tubular passage-way and its connection to the air valve
of the air tube and to the outer air.
Fig. 2, is an enlarged perspective detail of portion of the rim and tyre inter-
mediately broken away to exhibit the peculiar construction and arrangement of
the tube and its connections to the air tube and outer air.
Fig. 3, is a cross section through the rim and tyre showing the passage-way
leading across the tyre from the outer peripheral passage-way to the tube leading
to the air tube.
Fig. 4, is a sectional plan showing the location of both passage-ways leading to
the central peripherial passage-way.
In the drawings like letters of reference indicate corresponding parts in each
figure.
A is the rim. B is the tyre proper, C is the air tube and E the valve, which is
of the ordinary form or such a form as will be perfectly air tight when closed.
D is a peripheral passage-way, which is made preferably in flat form and is
preferably formed in the tyre itself near the centre of its outer periphery. D' is
a passage-way also formed in the tyre when moulded the same as the passage-
way D would be and extending from such passage-way D around the
cross sectional arc of the tyre, the internal surface thereof forming
a raised ridge d sufficiently strong to prevent the compression of the
passage-way D by the pressure of the air tube against it. The passage-way D
extends in the form of a tube Ds through the rim A and has connected to it a

page_text: tube D³, which connects with top cape of the valve E, which communicates with
and is connected to the interior of the air tube C in the usual manner.
It will thus be seen that one etid of the passage-way D ends in the valve E
which communicates with the air-tube. The other end of the passage-way D is
connected by a branch passage-way which extends from the passage-way
around the cross sectional arc of the tyre: B up in tubular form 1 through the
rin, where it preferably has a sleeved surrounding the end of the tube over
which is preferably placed a thin gauze to protect the dust from getting into
the passage-way such gauze being secured in position by a cap (see Fig. 2).
The passage-way D also is preferably located within the internal surface of the
tyre, being protected by a ridge d moulded with the tyre and which is of sufficient
thickness to prevent the pressure of the air tube from collapsing the passage-
way 'D'.
The passage-way D may be preferably lined on the outside with leather or any
suitable flexible non-puncturable substance or material or preferably I would
place and cement or otherwise fasten a band 2 of leather, light metal or other
suitable substance or material in a peripherial groove 3 around the entire periphery
of the tyre directly outside the passage-way leaving of course a sufficient thickness
of rubber to form the outer side of the passage-way. This will effectually prevent
the passage-way from being punctured under any circumstances.
It will of course be understood that it is necessary to have a certain pressure in
the air tube in order to provide for easy riding. It is, therefore, 'necessary should
the pressure in such tube become decreased by leakage or puncture that in order
that the air may be forced through the valve from the inner end of the tubular
passage-way, the pressure of such end must overcome the pressure of the air in
the air tube upon the valve as. well as tho pressure of the spring upon the valve..
It is therefore, compulsory that the size of the passage-way D and the length
thereof must be sufficient so that the pressure at the valve end must be increased
to pass the valve. This is of course accomplished at each revolution of the wheel
as it rotates in the direction indicated by arrow and depresses the portion of the
passage-way near the open end first and by the continuous running depression
along the whole of the passage-way the pressure is produced at each revolution
near the valve end sufficient to overcome the outward pressure exerted upon such
valve and thus forces the air in the passage-way into the air tube.
The amount of pressure of course depends upon the length of the passage-way
and its cross sectional area. When the compression accomplished by the rotation
of the wheel and compressing of the passage-way is equal to the pressure of the
valve outwardly plus the pressure of the air in such valve from the air tube, that
is to say when they are in equilibrium, of course there will be no air pumped into
the air tube.
In practice we find that ordinary punctures in the tyre will not effect the pre-
serving of the tyre at the proper resiliency as long as the rider continues to wheel.
The faster he wheels the quicker the pumping will be. It will be seen that this
invention will be extremely valuable not only in keeping the air tube pumped up
to the proper pressure but also should a puncture occur the rider will not have
to spend considerable time on the road to repair his tyre but may proceed home
with all possible dispatch and repair his tyre at his leisure.
If the valve used is one with any tendency to leak of course a faucet or tap may
be used outside the valve upon the tube D³ which would of course be closed when
the bicycle is not in use so as to prevent any possibility of the leaking of the air
from the air tube.
When the air tube of the tyre is pumped up sufficiently by our device as herein-
before described it will of course be understood that such faucet, which would be
a three-way one, with one orifice communicating directly with the outer air,
might be turned in such a manner as to admit the air into such orifice and allow
of its free passage through the open end and throughout the length of the tube
without having any tendency whatever to impel the air through the valve.

page_text: Having now particularly described and ascertained the nature of our said in-
vention and in what manner the same is to be performed, we declare that what we
claim is:-
1. A pneumatic tire having a circumferential passage located in the tread
thereof, lateral branches leading from each end of said passage to the exterior of
the tire and a connection between the outer end of one of said branches and the
interior of the tire, as specified.
2. A pneumatic tire having an automatic air pump consisting of a compressible
passage on its tread portion extending circumferentially thereof, and branch
passages located in the wall of said tire leading from said tread passage to the
exterior of the tire and a connection between the outer end of one of said branches
and the interior of the tire as specified.
3. The combination with a tire having a central air space, of a compressible
passage located circumferentially outside of the said central air space, said passago
being permanently in communication with the atmosphere and with said central
air space as specified.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicants.