Improvements in Valves for Pneumatic Tyres.
Year: 1895

page_text: Date of Application, 18th Jan., 1895-4ccepted, 23rd Feb., 1895
COMPLETE SPECIFICATION.
Improvements in Valves for Pneumatic Tyres.
A communication by ADOLF KNUSS and MARTIN HÄRTER, both of Fuerth,
Bavaria, in the Empire of Germany, Bath Proprietor and Mechanic,
respectively.
I, WILLIAM PHILLIPS THOMPSON F.C.S., M.I.M.E., of The Agency for
Foreign Patent Solicitors, 6 Lord Street, Liverpool, and 6, Bank Street,
Manchester both in the County of Lancaster and 31 High Holborn in the
County of Middlesex, Civil Engineer, 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 improvements in valves for pneumatic tyres. The
usual arrangement is such that a valve can only be used for inflating and not
also for automatically letting off any excess of compressed air. Safety devices for
preventing a certain pressure being exceeded have not as yet been employed with
pneumatic tyres.
This invention has therefore for its object to produce a valve for pneumatic
tyres which will serve not only for use in inflating and deflating the tyre, but also
as a safety valve, so that, when a given pressure is exceeded, either through
pumping or by expansion of the enclosed air, through heat, it allows the excess
pressure to escape. The peculiar construction of the valve makes the same
suitable for this threefold purpose, without involving a complication unsuitable for
its special purpose.
The construction of this improved valve is as follows and will be described with
reference to the accompanying sheet of drawings,
Figure 1 being a vertical section and
Figure 2 a plan view.
The nozzle b which is suitably connected with the air tube a has screwed thereon
a screw casing or cap e having a smaller tubular projection e' which may be closed
by a cap d provided with openings.
A safety valve, in the form of a sliding piece e washered by means of an india-
rubber or other like disc, is seated on an annular projection 6 formed on the base
of the nozzle b, and this sliding piece e is pressed on its seat b¹ by means of a spiral
spring bearing against the bottom of the screw casing c, and thereby an air-tight
joint is established closing the air outlet . The sliding piece e which is held or
guided vertically inside the nozzle b by guides or projections el forms the seat of an
air inlet valve and is for this purpose centrally bored.
A valve spindle is passed through the bore of the said sliding piece and has at
its upper end a head or knob f' serving to limit its stroke. The inlet valve acts
as a back pressure valve and is pressed against the washer disc g by the pressure
existing in the tyre, by which means it forms a tight joint.
When air is pumped in through the valve, the latter is pressed inwards so
that the headrests on the slide piece e and in order to allow of the
admission of air, radial grooves or furrows ¹² extending inwards are formed
in the upper end of the slide piece, through which grooves the air enters
the tube.
The valve herein before described acts in the following manner.
If the air tube a is to be inflated, the cap d is first removed, and air is injected
into the nozzle b by means of an air pump. When such air has reached a higher

page_text: pressure than the air contained in the air tube, the valve spindle f is pressed
downwards and the air flows into the air tube through the grooves k¹ k². The
closing of the valve, that is the pressing of the same on the washer disc g takes
place automatically under the action of the excess air pressure existing in the
air tube.
The part of the device forming the safety valve works in the following way.—
On the air pressure in the tyre becoming excessive, it lifts the slide piece e from
its seat b, and escapes round the same to the outside through the casing c¹.
This improved valve renders it possible, without exerting any special care, to
inflate the tyre to the limit of its capacity, without causing any damage to the tyre,
by reason of a too great internal pressure.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondents, I declare that what I claim is :-
An improved valve for pneumatic tyres adapted to act as an inflating, deflating
and safety valve, characterised by the arrangement within a nozzle (b) of a tubular
sliding piece (e) bearing under spring impulsion against a seating formed at the
base of the nozzle so as to close with one end the air outlet opening (1), the said
end of the tubular sliding piece also forming a seat for an air-inlet-valve (f) having
its spindle inserted through the tubular sliding piece; substantially as hereinbefore
described and shown.
Dated this 17th day of January 1895.
WM. P. THOMPSON & Co.,
Agents.