Improvements in the Manufacture of the India-rubber Coverings of Pneumatic and similar Tyres.
Year: 1894

page_text: Date of Application, 16th Jan., 1894
Complete Specification Left, 4th Aug., 1894-Accepted, 15th Sept., 1894
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of the India-rubber Coverings
of Pneumatic and similar Tyres.
We, WILLIAM HENKY CRESSWELL, Engineer, and HERBERT EDWARD COHEN,
Manufacturer, boch of Woodley Bank, Woodley, Stockport, near Manchester, do
hereby declare the nature of our said invention to be as follows:-
Our invention relates to the pneumatic and similar tyres of cycles and other
vehicles and has for its object so to manufacture the india-rubber coverings thereof
that instead of such coverings being made as heretofore in long strips and the two
ends thereof joined by cement or otherwise so producing a transverse joining which
as the tyre is used comes asunder, the same is inade in a complete belt form having
no joining whatever. Our invention also has for its object to supersede what is
known as the core moulding process which is very expensive and which leaves a ridge
on the tread of the covering.
In accordance with our invention we take a metal plate somewhat larger than the
diameter of a tyre and in the surface of this plate we cut or otherwise form an
annular groove corresponding to the required diameter and width of the covering
of a tyre previous to its being stretched onto the wheel.
Into this groove the india rubber to form the covering is introduced, by preference
in segmental strips and above the groove another plate is superposed to complete
the section. Heat being applied the india rubber is moulded to the section of the
groove which gives the covering a thin outside edge and a thick inside edge and the
usual thickness of these coverings in the centre. In this way the covering is made
in a complete and unjoined ring or annulus and in a flat form similar to an ordinary
elastic band with one edge of a greater circumference than the other. In applying
the covering to a wheel it is necessary to make its two edges of equal circumference
and to accomplish this we transfer the covering from the mould in a partly curved
state and apply it to a mandril on which it is stretched until its two edges are of
equal circumference and the thicknesses thereof are equal, the thick inner edge being
reduced to the thickness of the thin outer edge. The covering is now vulcanised
bringing the inside edge of the covering to the same circumference as that of the
outside edge which produces the required diameter for the covering when placed
upon the wheel.
To give the covering the required curved or half round section and adapt it to the
air tube of the wheel the mandril is of an oval or half round section so that the
operation of enlarging the inside circumference and the operation of curling are
performed at one and the same time.
In this way we produce a perfectly formed covering without any joining what-
ever. It will be obvious that a number of coverings may be formed simultaneously
by employing a number of plates or moulds. As one plate completes the mould
section of the groove in another plate the plates may be stacked one upon
another.
It will be therefore seen that the essential feature of our invention is forming the
covering in a flat continuous ring form and then transferring it to a mandril to bring
it to the required form for putting it on the wheel.
Dated this 12th day of January 1894.

page_text: Improvements in the Manufacture of the India-rubber Coverings
of Pneumatic and similar Tyres.
We, WILLIAM HENRY CRESSWELL, Engineer, and HERBERT EDWARD COHEN,
Manufacturer, both of Woodley Bank, Woodley, Stockport, near Manchester, do
hereby declare the nature of our said invention and in what manner the same is to
be performed to be particularly described in and by the following statement:-
Our invention relates to the pneumatic and similar tyres of cycles and other
vehicles and has for its object to manufacture the india-rubber coverings thereof in
a complete belt form, having no joining whatever. Our invention also has for its
object to supersede what is known as the "core moulding" process which is very
expensive and which leaves a ridge on the tread of the covering.
In accordance with our invention we take a metal plate and in the surface of this
plate we cut or otherwise form a shallow annular groove, the outer circumference of
which by preference corresponds to the diameter of the covering of a tyre previous
to its being stretched onto the wheel.
Into this groove the india rubber to form the covering is introduced, either in
segmental strips or in the form of rubber cord or otherwise and above the said
groove another similar plate is superposed to complete the section.
Heat being applied the india rubber is moulded to the form of the groove, which
is of such a section as to give the covering a thin outside edge and a thick inside
edge and the usual thickness of these coverings as at present made in the centre or
of any other thickness according to the sections of covering required.
In this way the covering is made in a complete and unjoined ring or annulus and
in a flat form similar to a washer or an ordinary elastic band with one edge of a
greater circumference than the other.
In applying the covering to a wheel it is necessary to make its two edges of
equal circumference and to effect this we transfer the covering from the mould and
apply it to a mandril or drum on which it is stretched until the circumference of the
inner edge is equal to the circumference of the outside edge when the thicknesses of
the two edges will be equal, the thick inner edge under the stretch being reduced to
the thickness of the thin outside edge. In this condition and whilst on the mandril
or drum the covering is vulcanised or introduced into a vulcaniser and retained
therein until such time as the inside edge of the covering has become set to its
stretched condition.
And in order that our said invention shall be the more readily understood and
carried into practical effect we have hereunto annexed a sheet of drawings and will
now proceed to describe the same with the assistance of the various figures and
letters of reference marked thereon.
Fig. 1 is a plan view of our improved rubber covering moulding plate and
Fig. 2 is a transverse section of two of such plates superposed shewing how the
mould for the complete section of covering is formed.
Fig. 3 is a plan view of our improved coverings as it appears after being removed
from the mould.
Figs. 4 and 5 illustrate forms of mandrils.
In accordance with our invention (A) is a plate of cast iron or other suitable
metal, of such a size or diameter as to allow of an annular groove (B) being
formed in it, the outside edge or circumference of which by preference corre-
sponds to the outside circumference of the covering to be moulded. The
width of this groove is of corresponding width to the width of the covering to
be moulded.
Into this groove the rubber to form the covering is introduced, by preference in

page_text: rubber cord form and when sufficient rubber has been put in, such groove is covered.
by a superposed plate the underside of which completes the section of the mould as
illustrated in Fig. 2.
Said plates being held or clamped tightly together so as to prevent the mould
section being altered, heat is applied either by locating the plates in a steam
heated press or in any other convenient manner, when the rubber is moulded to a
cross section corresponding to that of the groove (B). On removing the super-
posed plate the newly formed covering or ring is taken from the groove which is
obviously in the form of a complete ring or annulus as shewn in Fig. 3 with its cross
section corresponding to that of the groove in the plate.
In order now to bring the ring into its final shape, it is necessary to make the
diameter or circumference of the inner edge (C) to correspond with the diameter
or circumference of the outer edge (D) and to do this we employ a drum,
cylinder or mandril (E) (see Fig. 4) corresponding to the required circumference
or diameter of the outer edge (D) of the ring. Onto this drum the ring is placed,
the inner edge becoming necessarily stretched or distended to the diameter of the
drum, the thick inside edge becoming reduced to a thickness corresponding to that
of the outside edge. Whilst on this drum the rubber ring is subjected to the action
of steam or introduced into a vulcaniser by which means the stretch of the rubber
is removed and a permanent set given to the ring, the ring appearing as shewn on
the drum in Fig. 4.
In this way we produce a perfectly endless covering having no joining whatever
and it will be observed that the essential feature of our invention is moulding the
cover in flat endless form and "bringing up" of the inner circumference to
correspond with the outer circumference, the section of the covering being such as
will allow of this.
To give the covering the usual curved or semi-circular cross-section it may be
placed on a mandril with a rounded edge as shewn in Fig. 5, but as the edges of the
covering are generally very thin it will be an easy matter to apply the covering
without its being curved.
.
It will be obvious that to expedite the moulding of these improved coverings a
number of the plates (A), may be stacked one above another, the underside of one
plate completing the mould section of the groove in the plate beneath.
Having thus particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we wish it to be understood
that we are aware that it is not new to mould endless rubber objects by plates or
moulds superposed and therefore we make no claim broadly thereto, but what we
do claim is.-
1st. In the manufacture of coverings for pneumatic and similar tyres the process
of moulding the coverings in annular or ring form by means of super-posed plates or
moulds having annular grooves more or less of the cross section shown in Fig. 2,
and "bringing up" the inner edge of such coverings to a diameter and thickness
corresponding to the diameter and thickness of the outer edge substantially as set
forth and illustrated.
2nd. The plates (A) having grooves (B) or their equivalent substantially as and
for the purposes set forth.
Dated this 3rd day of August 1894.