Improvements in or relating to Textile Fabrics, suitable for Use in Pneumatic Tyres.
Year: 1894

page_text: Date of Application, 9th Oct., 1894-Accepted, 16th Mar., 1895
COMPLETE SPECIFICATION.
Improvements in or relating to Textile Fabrics, suitable for Use in
Pneumatic Tyres.
I, JOHN FULLERTON PALMER, of Riverside, County of Cork, State of Illinois,
United States of America, Gentleman, 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 an improvement in textile fabrics and'is more particularly
directed to an improvement in fabrics for use as an envelope for tubing of rubber
or the like. It is well-known that rubber has slight strain-resisting properties in
any direction excepting that involving a compressive strain, and it is therefore the
uniform practice in making tubing of rubber, or articles of other shape than
tubular, when they are to be subjected to internal pressure, to supply an envelope
to constitute the strain-resisting medium, of a material which while flexible is sub-
stantially non-elastic and sufficiently strong to hold the internal pressure referred
to. Heretofore, and until a recent invention of my own presently referred to, but
two modes of providing a strengthening medium have been practised, namely, to
wrap canvas, in strips or otherwise, about the tube, or to wind spirally about it
threads, usually of flexible fibrous material, such as linen, although under some
conditions wire has been employed. For many reasons canvas or any woven fabric
of a similar pature, unless made to have the special characteristic involved in the
invention hereinafter claimed, is objectionable as an envelope for rubber tubing,
especially if the tubing is to be employed under conditions where internal and
external pressure are applied, or under conditions where the tubing while under
tension by reason of internal pressure is to be subjected to vibration, as in the
case of water hose or bicycle pneumatic tyres. It is found that the crossing
threads of the canvas being under tension in all directions abrade each other
with consequent destruction of the fabric. It is found also to be practically
impossible to establish a limit of extensibility in the envelope, thereby to limit
the distension of the air tube with certainty where a material is employed, which,
like canvas, contains strain-resisting threads all of which present a wavy line.
As a means of overcoming the objections to the use of canvas aud at the
same time to avoid the inconvenience incident to the use of threads alone and
unprovided with any means for insuring a uniformity in their relations to each other,
the invention set forth in British Letters Patent No. 4926 of A.D). 1893 granted to me
was contrived, and the product there set forth is found entirely to answer the
purposes of its invention. It has gone into extensive use and is found to present
a substantially perfect envelope for tubing and the like, especially in connection
with bicycle pneumatic tyres, and to give to the tube a strain-resisting property
greater than has heretofore been considered practicable with the same thickness of
rubber in the wall of the tube.
The essential characteristic of the product set forth in said prior British Letters
Patent No. 4926 of A.D. 1893, lies in the fact that the strain-resisting threads
which constitute the envelope do not contact with each other in such a manner that
the tension upon either under the vibration to which the product subjected will
serve to abrade the others, or cause its abrasion by the others; that the strain-
resisting threads present a continuous straight as distinguished from a wavy line,
so that the utmost limit of their tension can be obtained at all times; that the
threads thus constituting the strain-resisting medium are applied several at a time
and during the application and after application are caused by the interposed

page_text: rubber to maintain a substantial uniformity in their distance from each other,
and, what is much more essential, a substantially parallel relation with each
other.
With further reference to the Specification of said prior British Letters Patent
I find that such a fabric as is there disclosed can be in a measure and for some
purposes with advantage produced without the employment of rubber as the medium
for holding the threads together and apart, and such an improvement is found in
the invention hereinafter claimed,.a. description of which is as follows, reference
being had to the accompanying drawings, in which-
Figure 1 is a plan view of a sheet of textile material forming part of my
invention;
Figure 2, a view illustrating the manner of applying two such sheets together to
constitute an envelope; and
Figure 3 is a view of a section of bosc, or other rubber tubing, showing 'the
manner in which an envelope involving my improvement is applied.
The fabric is produced by weaving through parallel warp threads of a substan-
tially non-extensible material, such as linen, occasional woof threads of a material'
comparatively easy of destruction by breaking or otherwise and preferably loose,
whereby the tension upon the warp threads does not produce at the point of
crossing of the woof threads a variation in the direction of the warp threads. With
the warp threads of linen the woof threads will ordinarily be of cotton or wool and
usually also much thinner than the warp threads; but the woof threads may y also
be of linen but thinner than the warp threads and hence more easily broken; or
may be of linen threads of the kind known in America as rotten threads, especially
prepared or otherwise. These "rotten" threads may be ordinary linen or other:
threads chemically treated so that whilst retaining their appearance and size their
strength is so reduced that they will break under much less stress than that which
they would support were they not so trented.
I do not limit my invention to any particular material in this regard, nor to any
particular relative dimension, so long as the characteristic remains that the woof
threads are so applied as not to interfere with the distension into a straight line of
the warp threads and are relatively fragile.
A represent the warp threads and B represent the woof threads, the latter
being disposed as indicated in Figure 1 preferably some distance apart, although
the invention is not limited to any particular distance, nor to the specific
arrangement illustrated in the drawing.
It will be obvious that a fabric constituted as illustrated in Figure 1 of a single
sheet will have great strain-resisting property in the direction longitudinally of the
warp threads, and will have substantially no strain-resisting property in other
directions, the amount of strain-resisting property being merely that found in the
woof threads which as explained is preferably very slight. Hence, as an envelope
for tubing, when applied in a single sheet such a fabric is of little value. It is
necessarily applied in such manner that the threads shall extend diagonally of the
tube so that both lateral and longitudinal distension of the tube is readily permitted.
In order to limit the distensibility of the tube both radially and longitudinally two
strips of such fabric are employed, being applied as indicated in Figure 2 in such a
manner that the warp threads of the respective fabrics cross each other at a greater
or less angle. The fabric may be made by laying one strip, preferably cut
diagonally of the warp fibre, upon another strip similarly cut and in such manner
that the fibres of one strip, present an angle to the fibres of the other strip, and the
double ply of fabric thus obtained is placed upon the tube to be covered; and in
the case of a straight length of tubing and other articles of rubber this mode of
procedure may be found efficacious; it is preferred however to apply the fabric by
cutting each strip into narrow lengths longitudinally of the warp fibre and to wind'
first one strip upon the tube in such manner that the edges abut without over-
lapping, and thereupon to apply the second strip similarly cut and wound, but, in a
direction which will cause its warp threads to present an angle to the warp threads

page_text: of the first ply. This is quickest done by winding it in the opposite direction with
the edges abutting without overlapping as in the case of the first strip. It is usual
to apply the first strip to the inner rubber tube before the latter is vulcanized, then
to apply the second strip, and thereupon to apply a second or outer tube of rubber
also invulcanized, the whole being then placed in the vulcanizing oven where the
usual pressure is applied to cause the rubber tubing, to become vulcanized and the
threads to become thoroughly united to the rubber. Becoming thus united to
the rubber the threads are caused to maintain their relation to each other to the
extent permitted by the elasticity of the rubber, and the product thereupon has
substantially the attributes found in the fabric which forms the subject of my said
prior British Letters Patent. The woof threads, having served their purpose for
holding the warp threads in proper relation to each other during the winding of
the fabric upon the tube, may be and sometimes are destroyed in vulcanizing; and
even if they are not their fragility is such as to permit them to break readily under
tensile strain laterally of the warp threads. This is an advantage rather than
otherwise, as it is important that the elasticity of the rubber in all directions,
excepting that parallel with the warp threads of the two plies of fabric, shall in no
way be materially reduced.
In some cases it is desirable before applying the plics of fabric to the tubing to
saturate them with rubber after the manner of the production of binding cloth,
and this step is contemplated as part of this invention, although it is not essential.
If desired before applying, the fabric to the tubing it may be laid upon a sheet
usually of thin unvulcanized rubber and pressed therein, thus producing the fabric
which forms the subject of my granted Letters Patent; and if desired it may be
the practice to apply both plies of fabric separately to strips of rubber, or to
opposite sides of a single strip of rubber before applying them to the tube,
the fragile woof threads employed serving to maintain the warp threads in their
proper relation to each other when introducing them into the sheet. These
procedures when practised are to be understood as included in the invention herein
set forth.
In Figure 3, C represents the inner tube, D, the first ply of fabric, E the
second ply of fabric and F the outer tube. It will be understood of course that
as many plies of fabric D E may be employed as desired, and in making the
tube the numbers of plies and outer tubes F may be varied according to the
necessity of the case.
Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed, I declare that what
I claim is;-
1. In a fabric for tubing-envelopes having substantially non-extensible fibrous
warp-threads relatively fragile woof-threads so applied as not to deflect the warp-
threads when under tension and affording a temporary or readily destruotible -
medium for holding said warp threads in position substantially as described.
2. A fabric for tubing envelopes comprising substantially non-extensible fibrous
warp-threads embedded in rubber, and relatively fragile woof-threads affording a
temporary or readily destructible medium for holding said ward-threads in position
and embedded in said rubber substantially as described.
3. Producing the fabric herein described by forming the warp with substantially
non-extensible and parallel fibrous threads weaving a temporary woof through the
warp-tbreads so as not to deflect them when under tension and embedding the whole
in rubber substantially as described.
1
4. The employment in a pneumatic tyre of the fabric herein described.
Toh J... Low 1004
W. P. THOMPSON & BOULT,
Agents for the Applicant.