Combined Automatic Safety and Inflating Valve for Pneumatic Tyres.
Year: 1893

page_text: Date of Application, 3rd Oct., 1893
Complete Specification Left, 24th Jan., 1894-Accepted, 30th June, 1894
Combined Automatic Safety and Inflating Valve for Pneumatic
Tyres.
ARCHIBALD WILLIAM WALLACE FORBES, 9 Bellevue Street and E. London
Street Edinburgh Engineer, do hereby declare the nature of this invention to be
as follows:-
The object of this valve is to prevent the bursting of air tubes of pneumatic
tyres from expansion of air caused by heating, either from the sun or from friction,
also by reducing undue pressure lessening liability to puncture. The pressure is
regulated by means of a metal spring, or should I think fit, of elastic buffer which
has a screw-adjustment & scale by which the maximum pressure permissible on the
various tyres is.regulated...
The valve at inlet is screwed to admit standard air pump & at outlet is corrugated
for fixing by wiring on air tube of tyre. The valve is also fitted with check valve
which prevents undue escape of air while being inflated.
The valve does away with the necessity for any other form of valve & is
constructed of metal or, should I think fit, of vulcanite.
2nd October 1893.
ARCH. WM. W. FORBES.
COMPLETE SPECIFICATION.
Combined Automatic Safety and Inflating Valve for Pneumatic
Tyres.
ARCHIBALD WILLIAM WALLACE FORBES, Engineer, 9 Bellevue Street and
E. London Street, Edinburgh, 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 :-
1. This valve consists of a metal tube for fixing to air tube of tyre forming an
inlet & outlet-outlet being made to form a seat for outlet valve.
2. Inflating valve tube screwed to fit air pump at one end, & at reverse end is
outlet valve in combination with seat for inflating valve.
3. A sleeve containing a spring and which screws over aforesaid outlet tube, &
presses outlet valve into position also presses spring to required tension-which
tension is indicated by index on sleeve.
The action of the valve is, that when the pressure in the tyre exceeds that for
which the valve is set the outlet valve is pressed outwards-allowing the air to
escape till pressure falls sufficiently to allow the valve to close.
This invention relates to valves for pneumatic tyres and is designed to prevent
the bursting & straining of pneumatic tyres through over inflating or expansion of
air through heating or other causes it is in conbination with an inflating valve and
pump tube. The tube a is fixed at one end to air tube of tyre at the other end
is made to form a seat for the outlet or safety valve B.
The pump tube C is screwed at one end to fit the air pump & at the other end
enlarged to the same diameter as the tube a forming the outlet valve B. The
outlet valve B is loaded by means of the spring E the required tension being
regulated by screwing the sleeve F onto the tube a & compressing the spring (E)
against the back of the valve B. The amount of compression to correspond with

page_text: the scale stamped on sleeve F & indicated by means of a pointer D held between
the spring E & valve B, & working through a slot on sleeve F.
The inflating valve (H) is contained in tube (a) working on a seat (I) which is
a continuation of pump tube (C). This projects over safety valve (B) & up into
inlet tube (a) the tube (C) being screwed to fit air pump at (9) (K) being a spring
to hold valve (H) in position.
Having now particularly described and ascertained the nature of my said inven-
tion & in what manner the said is to be performed I declare that what I
⚫claim is
In a valve for pneumatic tyres the combination of an inflating valve with an
automatic safety valve having an index & a screw adjustment by which the pressure
-can be adjusted to any required tension, thereby preventing the bursting & straining
of pneumatic tyres by expansion of air from whatever cause.
Dated this 23rd day of January 1894.