Improvements in or relating to Pneumatic Tyres.
Year: 1893

page_text: Date of Application, 21st Nov., 1893
Complete Specification Left, 21st Aug., 1894-Accepted, 6th Oct., 1894
PROVISIONAL SPECIFICATION.
Improvements in or relating to Pneumatic Tyres.
A communication from PIERRE MERCIER, of 42, Boulevard Bonne Nouvelle, Paris,
in the Republic of France.
I, ALFRED JULIUS BOULT of 323 High Holborn in the County of
Middlesex, Chartered Patent Agent do hereby declare the nature of this invention
to be as follows:-
The present invention is based upon the fact that if, in the wall or casing of any
receptacle filled with compressed gas, there should be a capillary opening,
i.e. extremely minute, but nevertheless permitting the escape of the said compressed
gas, and more particularly in case that wall or casing is formed of a membrane of
india-rubber not at all or very slightly distended, perforated by a sharp point-all
escapc of gas can be abruptly and completely arrested by simply wetting the edges
of the capillary opening with any liquid whatever. In such case the liquid, owing
to capillary attraction, quickly causes the solution of continuity, forming the opening,
to disappear, and consequently makes au air-tight joint. Further also, even if the
perforation were too large to constitute an opening of the capillary order, the liquid
applied, if it only be more or less viscous-like glycerine, for example-and used in
sufficient quantity, would escape, under the internal pressure of the gas, much less
rapidly than the gas itself, and, consequently, the receptacle becomes, in comparison,
more slowly exhausted.
On the other hand, if a thin sheet of india-rubber, of unequal thickness
throughout, is stretched in all directions at once--or if a rubber tube offering
variations in thickness is dilated, which is tantamount to the same thing-the
expansion of the various parts will be in inverse proportion to their thickness. If,
however, that rubber sheet, in lieu of having, at any given portion of its surface,
an extra thickness of its own material, were lined, at that particular part, with an
adhesive layer of some material like canvas etc. which does not stretch, the distension
would be limited to the unlined portions.
This invention is founded on these two principles and relates to an improved
air-tube or pneumatic tyre, formed of rubber which is lined on the tread or running
surface with an unelastic fabric, and into which I introduce a liquid of some kind-
either water with the addition of salt or glycerine to remain unaffected at low
temperatures; castor-oil.
The tyre being thickened, reinforced or strengthened with rubber or the like on
the tread the distension produced on dilatation by the air-pump, on the principle
herein before set forth, is confined to the thinner portion of the rubber which is in
contact with the rim, and in no way extends to the thickened part which comes in
contact with the ground. It is easily understood that if a perforation takes place
in the thick part of the tyre that perforation will remain in the capillary state and
will not therefore allow the air to escape, especially if well wetted by the fluid
introduced.
The game effect will be produced, only enhanced, if the increased thickness be
superseded by the linen-cloth stuck on to the tyre.
Dated this 17th day of November 1893.
W. P. THOMPSON & BOULT,
Agents for the Applicant.

page_text: гарготещению 11 of 1010ницу ю гейшанс тутов.
1 ALFRED JULIUS BOULT of 323 High Holborn in the County of
Middlesex Chartered Patent Agent do hereby declare the nature of this invention
a communication from Pierre Mercier of 42 Boulevard Bonne Nouvelle Paris
France 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 improvements in pueumatic tyres for velocipedes and
other vehicles and has for its object to prevent them from becoming deflated when
punctured.
My improvements are based upon the two following principles:
1.-When a capillary or very minute opening is formed in a receptacle filled
with compressed air, so as to allow a slight escape of the same, especially in a
receptacle having walls formed of an india rubber membrane which is either
slightly stretched or not at all, the escape of air can be suddenly and thoroughly
arrested by simply wetting the edges of the capillary opening with any suitable
liquid. In this case the liquid stops the opening by capillarity and thus forms an
air-tight joint.
Should however the perforation be larger than a capillary opening, the liquid
used inside the receptacle will not, if in sufficient quantity, be forced out by the
internal pressure of the gas as rapidly as the gas, and hence the receptacle will be
deflated at a much slower speed than if it contained no liquid.
2. When a thin india rubber sheet of unequal thickness throughout is stretched
in all directions, or similarly when an india rubber tube of varied thickness is
dilated by compressed air, the extension of the india rubber is in an inverse ratio
to its thickness. Likewise should this india-rubber sheet or tube, instead of being
thicker in parts, be lined in such parts with linen or other non stretchable material
made to adhere to the india-rubber in any suitable manner, the distension of the india
rubber would be coufined to the portion which is free from linen. Hence any
perforation occurring in that part of the india rubber which is thus protected is
unable to increase by reason of the distension of the india-rubber tube or sheet,
but remains capillary so as to be readily closed by any liquid in the manner above
set forth.
I shall now describe in § A the composition of the liquid used in my improved
tyres and in §§ B, C, D, E, F, G the various manners of manufacturing, according
to my invention, pneumatic tyres for velocipedes and other vehicles.
A. To close the capillary openings which may be formed in my improved air
chamber, I may utilize any suitable liquid so long as it wets the edges of such
openings, (which would not be the case with mercury,) and so long as it has no
action on the material of the tyre and is not too volatile.
Water is highly suitable and may be used alone, I may also use glycerine or a
mixture of glycerine and water capable of withstanding the cold weather, I may
also use for the same purpose a suitable saline solution.
I am aware that glycerine and other liquids have been used inside pneumatic
tyres and within air chambers, but their purpose was either to facilitate the sliding
of the walls one against the other, or to prevent the deflation of the pneumatic
tyre through dialysis; but liquids such as water had not been hitherto introduced-
in air chambers exposed to very small punctures for the purpose of closing them at
the time of their occurrence by reason of the capillary attraction between tho
liquid and the edges of such punctures.
Τ may add that the state of fluidity of the liquid used has no influence on the
result sought for, so long as such liquid wets the edges of the openings formed in

page_text: close proximity thereto. Thus instead of using a single liquid or a liquid mixture,
I may use a paste or dough moving slowly but soft enough to assume the shape of
the objects whereon it is placed, and hence a mixture of water aud glycerine to
which a little gelatine is added so as to somewhat impair its fluidity is highly
suitable.
B. With regard to the construction of my air chambers, I may form an air-
chamber of a plain tube of vulcanized india rubber having a inuch greater
thickness in the part which is nearest to the ground and most exposed to
accidental punctures, and introduce therein a given quantity of water or other
liquid..
Fig. 1 is a section of such a chamber when the same is inflated with compressed
air, the thin part AV B nearest the wheel rim will be readily expanded, while the
thick part AOB will be but slightly stretched, so that should the latter part be
punctured at 00', such puncture may slightly gape outwardly at O', but will
remain in a capillary state at O, and hence will not allow the escape of air if
properly wetted by the liquid inside the chamber.
C. Instead of making the tread of the tyre thicker to limit its expansion, I
may, according, to the 2nd principle above set forth, fix thereon by the aid of any
suitable adhesive means a strip of linen, woven with threads, (Fig. 2) crossing
each other at right angles and cut in the direction of parallel sets of threads and
preferably in the sense of its width, this linen controlling the expansion of the air
chamber when inflated with compressed air. I may apply the linen strip in the
course of manufacture, or afterwards, either inside, Fig. 3, or outside, Fig. 4, or
within the thickness of the chamber wall Fig. 5. The result is the same; when
these chambers are inflated with compressed air the part GV D alone expands,
and any puncture in the part held by the strip CD will be closed by the inside
liquid alone.
D. It is obvious that I may combine the chambers described under B and C and
form for instance a chamber with a thickened part covered or lined with linen such
as shown in Fig. 6.
I am well aware that air chambers have been made before with whole or partial
linen coverings. The linen, however was not used for the mere purpose of
maintaining the perforations in a capillary state which enables them to be closed
by a liquid, but it was used for a different object, that is to say for holding an
agglutinous material like ordinary rubber not vulcanized or for maintaining
vulcanized india rubber in a lateral compressive state.
My invention however is entirely different, as I do not seek to compress the
the india rubber by the linen but to support it so as to enable it to retain its
normal physical state, being neither compressed nor stretched or dilated and to
cause the punctures to retain their capillary form wherein they can be closed by a
liquid. I may even dispense with the linen as stated under or use it in a different
manner as hereunder set forth.
E. Instead of fixing the linen strip throughout its entire surface upon the
periphery of the chamber, I may fix the same by its edges only leaving the
intervening part loose. I may likewise cover or smear the linen band with
india-rubber and obtain thus an air chamber formed in the manner shown
in Fig. 7, wherein the linen strip covered with india rubber CEHFD is only
joined or soldered to the air chamber C G DV at the parts CE and F D whereas
the whole part E G F of the latter chamber is entirely loose.
When constructing the chamber in the above manner, according to known pro-
cesses, the part EGF of the air chamber is made of the same size as the part E HF
of the linen strip, or slightly larger, so that when the air chamber is inflated and
the part C. U D is expanded and pulls more or less upon the edges EC and FD
of the linen strip, the latter, owing to its small degree of expansibility, will never
It
exceed the size of the loose part FGF of the air chamber which it covers.
will be readily understood that under these conditions this part EGF, being never
stretched the perforations or punctures formed therein will remain capillary.

page_text: It is not necessary in the arrangement above described or in other similar
arrangement that the part EGF of the air chamber should be much larger after
inflation than the strip EHF; it will suffice, if in practice the linen strip EH F
was slightly extensible, that the part EGF should not expand sufficiently to
cause perforations made therein to relinquish their capillary state.
According to my invention it is preferable that the part EGF should not be
creased under the linen strip E HF after the air chamber has been inflated, as
should there occur folds such as shown in Fig. 8. These folds would form
concavities and convexities and the punctures p and p² which may be produced
would have a tendency to assume the conical form shown in the drawing and may,
owing to the thickness of the india rubber in this part, cease to remain capillary
and hence allow the compressed air to escape.
F-1 may make the part EGF of the air chamber above described thicker in
the middle Q GR (Fig. 9) than in the parts EQ and RF, or I may attain the
same object by providing the part QGR with a linen strip similar to the
strip GEHFD and leaving the elastic rubber parts EQ and RF free
(Fig. 10).
From the foregoing it will be understood that should a
perforation extend
through the two walls EHF and QGR the same would remain capillary in the
latter part and hence the air would not escape owing to the internal liquid.
G. I can substitute in the different cases above set forth any suitable fabric for
the linen-therein mentioned, such fabric consisting of one or more linen strips
provided with any suitable elastic or other coating in order to attain the object
in view which is to ensure the capillarity of the punctures, so that they may be
closed by a liquid. I thus form air chambers of the kind shown by way of
example in Figs. 11 and 12.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:
1. An air chamber for pneumatic tyres formed of a plain india rubber tube,
the tread of which is thicker than the other parts, Fig. 1, or is provided with
linen or canvas strips (Fig. 3. 4. and 5.) or is both thicker and covered or lined
with linen (Fig. 6), so that this tread may not be distended under the action of
the inner compressed air and that the punctures may be maintained in a capillary
state substantially as herein described and shown.
2. An air chamber for pneumatic tyres the tread of which is provided with a
linen or cauvas strip, coated or covered with india-rubber or not, such strip
adhering thereto by its edges only, so as to leave the intervening surface loose
substantially as herein described and shown in Fig. 7 of the drawings.
3. An air-chamber of the kind described in the above claim wherein the air
chamber proper is thicker or centrally covered or lined with linen or canvass
substantially as herein described and shown in Fig. 9 & 10 of the accompanying
drawings.
4. The modification of my invention substantially as hereinbefore described and
shown in Figs. 11 & 12 of the accompanying drawings.
5. The process whereby capillary punctures in the air tubes of pneumatic tyres
can be closed by any suitable liquid introduced therein beforehand, capable of
wetting the edges of such punctures, substantially as herein described and for the
purpose set forth.
Dated this Twentieth day of August Eighteen hundred and ninety four.
J. A. DE KATON,
For A. J. Boult.