Improvements in Pneumatic Tyres and in the Method of Producing Protectors therefor.
Year: 1893

page_text: Date of Application, 27th June, 1893
Complete Specification Left, 27th Mar., 1994-Accepted, 5th May, 1894
PROVISIONAL SPECIFICATION.
Improvements in Pneumatic Tyres and in the Method of Producing
Protectors therefor.
I, Alfred SOUTH DAVY of 2 Peel Terrace, Wilkinson Street, Sheffield, in
the County of York, Manager of Steel Works, do hereby declare the nature of
this invention to be as follows:-
:-
My invention has for its object to provide means whereby the puncturing of the
air-tubes of pneumatic tyres may be effectually prevented, and the invention
consists essentially in the introduction between the air-tube and the outer sheath
or cover, or by embedding in the thickness of the sheath itself, of a thin steel
ribbon which has been curved both transversely and in the direction of its length
to suit the transverse and circumferential curvature of the tyre as hereafter
described.
The strip is of sufficient breadth to protect the tread and vulnerable portion of
the tyre, and the two-fold curvature above referred to may be imparted to it either
by drawing the metal principally towards the centre of the width of the strip, and
to a gradually diminishing extent towards the sides, at the same time that the
transverse curvature is imparted to it; or instead of giving the longitudinal
curvature by extending the central portion of the strip it may be given by
contracting the marginal portions by forming therein transverse corrugations
extending from each edge and tapering off or diminishing towards the middle of
the strip; or instead of corrugations transverse slits may be made from the edges
towards the centre, those from the one edge alternating with those from the other
edge.
In any case the strip is operated on when in the soft state and may be
subsequently hardened and tempered if necessary to give it the necessary elasticity
and power to resist penetration.
If the double curvature is imparted by drawing, this may be done by means of
three rolls of suitable configuration the strip being brought to an endless or
annular form by a lapped or butt joint, and run round continuously between the
rolls which are gradually fed up to the work until the latter is brought to the
desired configuration.
If the form be imparted by corrugating, this may be done by a single pair of
rolls, the corrugating which gives the combined transverse and longitudinal
curvature being performed either at a single operation or at two separate operations,
the gradual merging of the corrugations with the plain central portion of the strip
being either produced by making the corrugations in the rolls of that form, or by
corrugating the strip uniformly across and then flattening them out at the middle
by rolling so as to kill the transverse rigidity caused by the corrugations.
If the strip be cross-slit, this would be done when in the flat and the transverse
curvature then imparted by passing between a pair of rolls of suitable configuration,
the slits permitting the easy bending of the transversely curved strip to the
circumference of the wheel when "in situ."
If the strip be introduced between the air tube and sheath it would preferably be
attached to the inner surface of the latter and be covered by tapes cemented on to
protect the air tube from chafing.

page_text: To prevent any tendency of the steel ribbon to creep, it may have small nodules
or protuberances stamped up in it by the rolls or otherwise.
Dated this 27th day of June 1893.
DAVV
By A. M. & Wm. Clark,
53, Chancery Lane, London, Chartered Patent Agenta.
Improvements in Pneumatic Tyres and in the Method of Producing
Protectors therefor.
I, Alfred SOUTH DAVY of 2 Peel Terrace, Wilkinson Street Sheffield, in
the County of York, Manager of Steel Works, 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 has for its object to provide means whereby the puncturing of the
air tubes of pneumatic tyres may be effectually prevented and the invention
consists essentially in rendering the tyre non-perforable by introducing between
the air tube and the outer sheath or cover, or by embedding in the thickness of the
sheath itself, a thin ribbon preferably of tempered steel, which has been curved
both transversely and in the direction of its length to suit the transverse and
circumferential curvature of the tyre as hereafter described.
The strip is of sufficient breadth to protect the tread and vulnerable portion of
the tyre and the two-fold curvature above referred to is imparted to it by
contracting the strip at the edges and to a gradually diminishing extent towards
the centre. This contraction of the marginal portion of the strip is effected by
forming therein transverse corrugations extending from each edge and tapering off
or diminishing gradually towards the centre of the strip.
In any case the ribbon or strip if of steel is operated on when in the soft state
and would be subsequently hardened and tempered to give the necessary elasticity
and resistance to penetration, but other metals than steel inay be employed.
The accompanying drawings illustrate on an enlarged scale the nature of the
invention and the means employed in producing the same wherein
Figure 1 is a section of part of a pair of plain rolls with curved faces for giving
the transverse curvature to the strip.
Figure 2 is a section of part of a pair of corrugating rolls.
Figure 3 is a perspective view of part of the finished strip.
Figures 4 and 5 are cross sections of the tyre shewing the position of the strip
therein.
The combined longitudinal and transverse curvature may be imparted to the
strip a at one operation by passing it between a pair of corrugating rolls B of the
form shewn in Figure 2, or it may first be passed between a plain pair of rolls A
such as shewn in Figure 1 to give it the desired transverse curvature and then
through the corrugating rolls B Figure 2 suitable guiding devices (not shewn) being
of course provided to prevent the strip from deviating from its proper position in
passing between the rolls. By its passage through the rolls B shewn in Figure 2
the strip is corrugated as shewn in Figure 3 with corrugations b extending from
each edge inwards towards the middle of the strip, the corrugations diminishing in
depth from the edges inwards and dying out or merging with the normal surface of
the strip at or before reaching the centre of the width of the strip.
The depth and pitch of these corrugations are proportional to the difference of
radius of the edge of the strip and the middle of the strip when curved transversely
and longitudinally to the form and diameter of the wheel tyre.
Without in any way limiting myself to actual dimensions, it may be mentioned
that it is proposed to use for a wheel of a diameter of 30 inches (= 75 c/m) ribbon

page_text: steel (similar to that used for making pens) about 14 inches (= 38 m/m) wide,
003 of an inch (= 076 m/m) thick, and the depth of the corrugations at the
extreme edges being about 0625 inch (= 1.58 m/m) and their "pitch" being about
125 inch (3.16 m/m).
The strip having been brought to the corrugated form as shown, is then hardened
and tempered in the ordinary way of tempering such goods. Supposing the strip a
is to be applied to the inner surface of the sheath C as shewn in Figure 4, it would
be covered on the inner face by one or more strips of rubber coated canvas c of
greater width than the metal strip a, so that the edges of the canvas extend beyond
those of the metal strip and may be cemented to the inner surface of the sheath C
both to prevent the inner air tube (not shewn) from coming into contact with
the metal strip a and to retain the latter securely in position. The ends of the
strip a would merely overlap a short distance, their corrugations fitting into each
other without being otherwise united. The strip a may be applied to the inner
surface of the sheath C, after or in course of manufacture of said sheath. In the
latter case the canvas covering c would be first applied to the core on which the
sheath is to be moulded, then the metal sheath a, and finally the sheath C would
be built up or moulded thereon in the ordinary way and vulcanized with the strip
in position therein. If the strip is to be embedded in the thickness of the
sheath, as shewn in Figure 5, it would be built up or moulded in a similar
manner.
Although I have spoken of applying the strip a in the sheath C forming the
outer cover for the air tube, supposing one to be used, the use of an inner air tube
is not necessary if means be provided of closing the sheath C airtight in which
case C would be the inflated tyre itself. Such means of closing the sheath C and
dispensing with an inner air tube are not shown and described, being already known
and therefore forming no part of this invention.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1st. A protector for pneumatic tyres, consisting of a ribbon of metal curved
both transversely and longitudinally and having transverse corrugations extending
from the edges and gradually diminishing in depth to zero at the middle, as and
for the purpose specified.
2. The combination, with a pneumatic tyre, of a ribbon of metal curved transversely
and longitudinally, and having transverse corrugations of gradually diminishing
depth from the edges inwards and applied to the inner surface of, or embedded in,
the thickness of the tyre, substantially as specified.
Date
By A. M. & Wm. Clark,
A. S. DAVY,
53, Chancery Lane, London, Chartered Patent Agents.