Improvements in the Manufacture of Tyres for Cycles and other Vehicles, and of other Elastic Articles.
Year: 1897

page_text: Date of Application, 30th Mar., 1897-Accepted, 26th Mar.,
1898
Improvements in the Manufacture of Tyres for Cycles and other
Vehicles, and of other Elastic Articles.
I, LOUIS LE BROCQUY, of No. 3, Clanwilliam Place, in the City of Dublin, in
Ireland, Manufacturer, 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 improvements in the manufacturo of tyres for cycles and
other vehicles and of other elastic articles which are now made of india rubber.
According to my invention I produce a mixture mude principally of glue and
glycerine melted together in any convenient manner and generally in about equal
proportions to which is added a very small amount of chromic acid, bichromate of
potash or bichromate of soda. Other materials such as cork, clay, sulphate of
bartum and the like may be added to make the finished article lighter or heavier or
of a less or greater solidity as desired. Finally the compound when formed into
its final shape is provided with a cover or coating of india rubber, gutta percha,
leather or the like to provent the compound being damaged or prejudicially affected
by moisture or otherwise.
In manufacturing according to my invention I proceed as follows : -
I put in a vessel, provided with a hot water or steam jacket, about a quarter
of the quantity of glue required, say 12 pounds and add thereto a small quantity of
water to aid its dissolving. When this glue has all dissolved the remainder of
the glue, say 35 pounds is gradually added. When all the glue is melted tho
boiling is continued until such time as white bubbles come to the surface which is
a sign that all the water has been evaporated. To this melted glue is gradually
added the glycerine at an equal temperature and weighing say 48 pounds and the
glue and glycerino are constantly kept stirred or agitated until the resulting
mixture has become perfectly homogeneous. The mixture is then allowed to
cool until its temperature is say 50° C. which is near its solidifying point. A small
amount say 5 pounds of a 5% solution of chromic acid at the before mentioned
temperature is then added during constant stirring. The object of the temperatures
of the constitutont parts being equal is to facilitate the proper and easy mixing.
The mixture should now be used at once, either being poured or forced by the aid of
pressure into, or through moulds, that is to say the mixture may be poured or
forced into a mould of ordinary construction, or it may be forced through a tube
of any desired internal section to produce a solid bar or tube of any desired size
and section in any well known manner. When the mass has cooled in the mould,
it is removed and covered with a cover or coating of india rubber, gutta percha or
the like. The compound described is elastic and has the properties in that respect
of soft india rubber, but in order to prevent it from deterioration by damp or other-
wise it is covered with a coating of india rubber or the like as aforesaid. It should

page_text: be noted that the compound should be made to assume the shape it is desired it
should finally have while warm and still in the liquid state as it sets when cold and
it is difficult although not impossible, to again melt it. Instead of covering the
compound with india rubber or the like after it has been removed from the mould,
I may run or force the molten mixture into a tube, hollow ball, or other object
and seal up the hole or holes through which the mixture has passed but in any case
I prefer that the mixture or composition should be enclosed in its covering before
the oxydising action of the suns rays should have time to take place. When the
mixture in the mould or covering has become cool it is heated in boiling water for
one or two hours until it has attained the temperature of 100° C. when it may bo
withdrawn and allowed to cool again. Or instead of being heated it may be stored
away for a few days when the action of the chromic acid will have taken place and
the compound will be equally unaffected by change of temperature. Or I may
enclose the mixture in a coating or covering of unvulcanized rubber first and
vulcanize the rubber afterwards.
If it be desired to make an article suitable for being used as a substitute for one
made of hard india rubber or gutta percha I employ for example 65 pounds of
glue, 22 pounds of glycerine, to which I add 8 pounds of clay, or 20 pounds of
sulphate of barium or cork or the like which I mix in before the addition of
5 pounds of chromic acid solution or its equivalent. I prefer to mix tho inert
materials such as clay cork sulphate of barium or the like with the glycerine before
adding same to the molton glue. The more clay or sulphate of barium is added
to the mixture the heavier will the resulting compound be and the more cork is
added the lighter will the said compound be. It is also evident that I may add
more or less of either or some or all of such additional materials to give the
compound a certain specific gravity but it is preferable that the percentage of such
additional material or materials should not exceed about 30 per cent, of the total
weight of the mixture.
In order to make the compound harder the proportion of glue is made large but
it should not preferably exceed 75% of the total weight of the compound and in
order to make the compound softer the proportion of glue may be as low as
about 35%-
It is of great importance that the proportion of chromic acid or the like should
be as small as possible, as when using a large proportion the compound finally
becomes too hard and brittle and the finished article will be consequently unfit to
serve as a substitute for one made of india rubber or gutta percha. The propor-
tions specified have been found to give good results but it is evident they may be
varied to a certain extent without departing from my invention. In fact
desirable that the compound should not be entirely chromated so as to permit the
mixture of glue and glycerine to retain its original properties of resiliency and
cohesion with a high melting point.
is
In addition to the manufacture of tyres for cycles and other vehicles and balls
may also make billiard table cushions, buffers, rollers, and other articles according
to my invention.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed I declare that what I
claim is:―
1. The improved manufacture of tyres for cycles and other vehicles and of other
elastic articles consisting of a mixture of glue glycerine and chronic acid or its
equivalent in or about the proportions stated such compound or mixture being
provided with a covering of india rubber gutta percha leather or the like
substantially as described."
2. The improved manufacture of tyres for cycles and other vehicles and of other
elastic articles consisting of a mixture of glue and glycerine and of ground cork or
clay or sulphate of barium or the like or some such material or materials and
chromio acid or its equivalent in or about the proportions stated such compound or

page_text: mixture being provided with a covering of india rubber, gutta percha leather
canvas or the like substantially as described.
Dated this Thirtieth day of March 1897.
JENSEN & SON,
77, Chancery Lane, London, W.C., Patent Agents.