Year: 1896

page_text: Date of Application (in United Kingdom), 15th July, 1896
Complete Specification Left, 14th Nov., 1896-Accepted, 30th Jan., 1897
PROVISIONAL SPECIFICATION.
I, JAMES SMITH of Ann Street, Petrie's Bight, Brisbane, in the Colony of
Queensland, Bicycle Importer, do hereby declare the nature of this invention to be
as follows:-
Hitherto the discovery and location of minute leaks in the inner or air tube of
pneumatic tyres has been a source of trouble owing to the fact that the tube when
removed from the wheel being deprived of the support afforded by the outer
covering cannot by itself withstand sufficient pressure to enable the leak to be
easily located and is liable to be burst by excessive inflation.
My invention relates to means for enabling as great, or even greater, pressure
to be applied to the air tube as when it is enclosed in the outer casing and in
position on the wheel.
My invention consists of a suitably shaped apertured box or case (which may be
made of perforated sheet copper, woven wire, or other suitable material) adapted
to temporarily enclose and support the air tube so as to enable it to withstand
internal pressure and which, owing to its numerous perforations or meshes, allows
the air escaping at the puncture or leak to pass through adjacent perforations or
meshes so that when the whole is dipped into a bath of water the position of the
leak can be at once seen and be located by stabbing the tube through the
perforations or meshes.
In order that my invention may be clearly understood I will now describe it
with reference to the accompanying drawings in which
Figure 1 shews the box or case complete and provided with a gauge to indicate
the pressure on the tube.
Figure 2 is a cross section of the box or case at the gauge.
Figure 3 is a cross section of a box or case made somewhat differently and
having a stiffening rim or bead formed on each member of the case.
The box or case is composed of an inner half member of semi-circular section
and which for bicycles would be made in the form of a complete ring to suit the
size of the tubes and diameters of the wheels in use. It is provided with a bole B
for the inflation tube and valve of the air tube to be inserted and it is also fitted
with a graduated pressure gauge Coperated by the pressure of the rubber tube
against a saddle piece D of corresponding curvature to the inner case. The edges
to this half of the box or case I prefer to wire as shewn in Figure 2. The outer
half member E of the box or case is also of semi-circular section and is made with
a joint formed by the ends overlapping and secured by a screw stud F to admit of
being sprung open as hereafter mentioned. The edges of the half E are wired and
fit, as shewn, outside the edges of the inner half A the two together forming an

page_text: so that when the air tube thus temporarily enveloped or reinforced and inflated is
dipped into water, the position of the leak will be at once indicated and can be
located by stabbing the tube through the perforations or meshes of the envelope at
which the bubbles appear.
In order that my invention may be clearly understood I will now describe it in
reference to the accompanying drawings in which
Figure 1 shews the case or envelope complete and provided with a gauge to
indicate the pressure in the tube.
Figure 2 is a cross section of the case or envelope at the
gauge.
Figure 3 is a cross section of a case or envelope made somewhat differently and
having a stiffening rim or head formed on each inember of the case.
The case or envelope is composed of an inner half member of semi-circular section
and which for bicycles would be made in the form of a complete ring to suit the
size of the tubes and diameters of the wheels in use. It is provided with a hole B
for the inflation tube and valve of the air tube to be inserted, and it is also fitted
with a graduated pressure gauge C operated by the pressure of the inflated rubber
tube against a saddle piece D of corresponding curvature to the case.
The edges
of this half of the case or envelope I prefer to wire as shewn in Figure 2.
The outer half member E of the case or envelope is also of semi-circular
section and is made with a joint formed by the ends overlapping and secured by a
screw stud F to admit of being sprung open as hereinafter mentioned. The edges
of the half E are wired and fit, as shewn, outside the edges of the inner
half A, the two together forming an annulus of circular section adapted to enclose
the air tube. Or the two parts A and E may be flanged and bolted or clipped.
together.
In some cases it will be found that the pressure of the inflated tube or bladder
will hold the outer half in place without any other fastening.
I prefer to make both halves A and E of perforated sheet copper as immersion
in water does not cause oxidation; but other material such as woven wire or other
strong materials having meshes or perforations can also be used. For bicycle
tyres as at present used I find a plain semi-circular section, as in Figure 2, quite
strong enough but in some cases it may be found necessary to strengthen the case
by forming a bead along the centre of each member, as in Figure 3, or by wiring
them, while stronger and other means of fastening the outer rim may also be used.
For use in testing the air tubes of the wheels of heavier vehicles the design of
the case or envelope would be modified to suit, while the outer half would for
convenience be made in two or more pieces connected together by suitable
fastenings.
I will now describe the working of my invention as applied to bicycle wheels.
The inner or air tube to be tested is put in place around the part A. as on a wheel
rim, the air valve being put through the tube B. The outer half E is next sprung
open slightly and placed over the air tube and when in proper position the ends
are secured by fastenings F. The air tube can then be pumped up to the desired
pressure, the indicator being suitably graduated shewing the amount.
The cap is
then placed on the valve and the whole immersed in a bath of water, when the air
leaking from the tube escapes through the nearest perforations or meshes and
appears as bubbles formed in the water. The position of the leak can at once be
located and marked by stabbing with a pricker through the nearest perforation or
mesh and if the pricker is first dipped in coloured oil paint the position can be
readily seen on the air tube when removed from the case.
The form of the case or envelope can be modified for convenience and the sides
made parallel with rounded ends.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A tester for the inner tube or bladder of a pneumatic tyre, consisting of a