Improvements in Apparatus for Automatically Charging Pneumatic Tyres.
Year: 1897

page_text: Date of Application, 6th Dec., 1897
Complete Specification Left, 4th Aug., 1898-Accepted, 10th Sept.,
1898
PROVISIONAL SPECIFICATION.
Improvements in Apparatus for Automatically Charging Pneumatic
Tyres.
I, WILLIAM ADOLPHUS HARRIS, of 30, Farringdon Street, in the County of
London, Secretary to a Public Company, do hereby declare the nature of this
invention to be as follows:
My invention relates to apparatus for automatically charging to a certain
pressure the pneumatic tyre of a wheel that revolves on a stationary axle.
For this purpose, I fix on the axle an eccentric sheave and in the nave of the
wheel I form or fix a pump cylinder having its axis radial. This cylinder is
fitted with a piston jointed to the eccentric rod.
The outer end of the pump cylinder is formed as a cylindrical chamber con-
taining a sliding plunger which is pressed outwards by a spring adjusted to the .
pressure desired in the tyre. An inlet for air opens into that part of the chamber
which is under the plunger and from this part a suction valve opens into the
pump cylinder. In the plunger and the sides of its chamber are formed ports,
one of these leading to a discharge valve, seated on the plunger, and beyond
the plunger there is a pipe leading to the interior of the pneumatic tyre. As
the wheel revolves, the pump piston makes its strokes drawing air in by the
suction valve and forcing it by one of the ports to the discharge valve, and
thence by the pipe into the tyre. When the pressure in the tyre is such as to
force the plunger back in opposition to the spring, the plunger closes the lateral
port leading to the discharge valve and opens a lateral port leading to the air
inlet, so that, when the desired pressure is attained in the tyre, the pump merely
draws in and expels air without farther charging the tyre.
AL
Thamber 1907
ABEL & IMRAY,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Apparatus for Automatically Charging Pneumatic
Tyres.
I, WILLIAM ADOLPHUS HARRIS, of 30, Farringdon Street, in the County of
London, Secretary to Public Company, 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 relates to apparatus for automatically charging to a certain
pressure the pneumatic tyre of a wheel that revolves on a stationary axle.

page_text: By way of example I shall describe my invention as applied to a wheel of a
bicycle or other velocipede referring to the accompanying drawings:
Figures 1 and 2 are central vertical sections of part of the wheel on planes
at right angles to each other. Figure 3 is a part section shewing a modification.
On the stationary axle A I fix an eccentric sheave B surrounded by a strap C,
the bearing of the strap on the eccentric being preferably, a ball bearing as shewn.
To an extension of the strap C I joint a packed piston' D which is guided by
rods d and works in a cylinder E. This cylinder is attached to a casing F
which is integral with the nave G of the wheel and forms a casing for the
eccentric. The cover of the cylinder E is extended to form a cylindrical cavity H
in which works a piston slide valve I which is urged outwards by a spring i
and is provided with passages and grooves kl related to lateral ports and pas-
sages KL formed in the wall of H. At M is a suction valve and at N is a
discharge valve. P is a pipe leading to the pneumatic tyre. The apparatus
operates as follows.
While the wheel revolves, the piston D is caused to reciprocate, drawing in
air by the suction valve M, and discharging it past the discharge valve N whence
it passes by the pipe P to the interior of the pneumatic tyre charging it with
compressed air. When the pressure attains a certain point determined by the
strength of the spring the slide valve I is forced back thus closing the mouth
of the passage K which previously opened to the groove k, and opening the
groove to the passage L so that air forced along L returns by the groove 7 and
the central passage to the cavity containing the spring which has lateral openings
to the outer air. Excessive pressure in the tyre is thus prevented.
In the modification shewn in Figure 3 the cylindrical cavity H is fitted with
⚫ a piston Q the stem of which is attached to a movable bottom R of the cylinder E.
On this movable bottom is fixed the suction valve M and through it there are
several holes. The piston Q is packed by a hollow caoutchouc ball made with
two projecting tubular parts which are secured in screwed sockets. While the
pressure in the tyre is being raised, the spring i keeps the bottom R pressed
against a caoutchouc or other yielding seat, but when the pressure in the tyre
is such that the piston Q is pushed down in opposition to the spring ? then the
bottom R being moved away from its seating gives free passage for air through
its holes, so that the pump merely draws in and discharges air at atmospheric
pressure without sending any air to the tyre.
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 combination with a wheel revolving on a stationary axle and having a
pneumatic tyre, an air pump mounted on the nave of the wheel, worked by an
eccentric on the axle, and having its discharge communicating with the interior
of the tyre, substantially as and for the purpose set forth.
2. In apparatus such as is above referred to, a spring piston subject to the
pressure in the tyre and arranged to operate a valve which puts the discharge
of the pump in communication with the suction, when sufficient pressure is
attained in the tyre, substantially as described.
Dated the 4th day of August 1898.