Year: 1889

page_text: Date of Application, 17th Jan., 1889
Specification Accepted, 23rd Feb., 1859
I, ERNST HÜLLER, of Hammer, by Mögeldorf, near Nuremberg, in the Empire of
Germany, 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 :-
--
The bearings heretofore employed for supporting shafts and the like are provided with
bushes which are made of brass, bronze, or other suitable metal or metallic alloy. Such
bushes serve thoir purpose in a sufficiently satisfactory manner, if care be taken that
a layer of the lubricant which is absolutely necessary for decreasing the friction shall
be between the rubbing surface and the surface rubbed, that is to say, between the
shaft and the bush. If the lubrication of the aforesaid surfaces is omitted the friction
will generate heat which rapidly increases and may become so great that not only the
metal of the bearing melts but the accessory parts are also heated to an injurious
extent.
Accordingly a suitable material for bearings would be one which contains the oily
or fatty substance indispensible for diminishing the friction, so that in case the
lubrication has been omitted the aforesaid inconveniences will be obviated. Metals.
are, however, not suitable for this purpose because none of them is porous enough to
receive in itself oils or fats.
In accordance with the said invention I use leather which is subjected to suitable
preparatory treatment in order to render it available for the purpose for which it is
designed.
I preferably employ waste such as occurs in the manufacture of leather belts, or
waste pieces or scraps, of hides and the liko, the said waste being reduced to such a
degree that neither large pieces will remain nor powder formed, as the latter does
not possess the fibrous qualities necessary for the cohesion. The reduction may be
effected by means of knives, planes, scrapers or similar instruments, in case the leather
at disposal has not been obtained in a reduced state by previous treatment, such a
for example, shavings produced in the treatment of hides, which shavings can be used
without being subjected to a reducing operation.

page_text: The reduced leather is softened in a hot solution of animal or vegetable glue, so
much of the solution being used as is necessary to obtain a tenaceous but not very
liquid pulp. The temperature of the said solution must not be high enough for a
decomposition of the leather to take place; a high temperature is however suitable,
as it enables the pulp to obtain the softness necessary for the subsequent trentment.
The aforesaid pulp is stirred until it has become quite uniform; and is then subjected
to a preliminary pressure, for the purpose of separating the glue which is not
absolutely necessary for the cohesion. The leather is next placed in moulds which
have been previously heated, and is subjected to a high pressure. The moulds which
are preferably made of metal are usually rubbed with graphite in order to obviate the
adhesion of the leather and enable the latter to be readily separated from the said
moulds. The necessary pressure is produced by means of suitable screw, hydraulic
or other presses according to the size of the mould.
After the pressing operation the leather is dried, which drying must be slowly
effected in the mould and in hot air, and must be continued until perfect dryness has
been attained, which according to the thickness of the leather takes several days or
weeko.
Bushes of bearings which have been made in the manner above described can
immediately be used in lieu of the ordinary bushes of metal, wood or other material.
The aforesaid bushes do not require any increased lubrication, their bearing surfaces
become very smooth by use, the shafts are kept in a much better condition by them
than by metal bushes, they are (moreover) almost indestructible and present the
great advantage of not occasioning such destructions as the metal bearings in case
the lubrication is omitted.
Instead of making the whole bush of the bearing of leather, I sometimes employ
a bush of other suitable material and provide it with a lining of the leather prepared as
above described or of ordinary leather. For this purpose either the bush of the bearing,
or the standard is suitably provided with dove-tail grooves extending in the direction
of the axis of the shaft, in these grooves being inserted suitablo strips of leather
prepared as described or of leather which has been cut directly from the hide. The
mode in which these leather strips or leather pieces are inserted, either in the metal
bushes, or in the standards of the bearings, that is to say, when bushes are not used,
can be adapted to the requirements of each separate case; it is understood that I do
not limit myself to fixing the same exclusively by means of dove-tail grooves.
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 :-
First. A journal or other bearing or a bush therefor made of small pieces or
scraps of leather by reducing the same and mixing them with animal or vegetable
glue, and pressing and drying the product in a mould.
Second. A journal or other bearing or a bush therefor made of metal and provided
with a lining or bearing surface, of ordinary leather or of leather prepared as horein-
before described.