Improvements in the Manufacture of Emery Wheels.
Year: 1891

page_text: Date of Application, 14th July, 1891
Complete Specification Left, 9th Apr., 1892-Accepted, 14th May, 1882
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Emery Wheels.
I ROBERT LUKE of Lime Bank Works Ardwick Manchester in the County
of Lancaster Engineer, do hereby declare the nature of this invention to be as
follows:
For the manufacture of emery wheels in which shellac is used for binding the
emery, the shellac and the emery are each heated independently, to the temperature
best suited to the manufacture, appropriate apparatus being employed in each case
for beating the materials so as to secure regularity in their temperature. Steam
jacketted vessels may be used for this purpose; and though for heating the shellac
this is perhaps the best system, it may sometimes be more convenient to heat the
emery in an oven specially constructed and heated so as to facilitate the convenient
regulation of the temperature.
The two ingredients having been raised to the desired temperature, the emery is
transferred to the vessel containing the now.melted shellac and the two ingredients
are mixed together by stirring the heating of the containing vessel being.continued
in the meantime. This stirring process does not however mix the ingredients as
intimately as is necessary for producing thoroughly reliable wheels of uniform
quality; and in order to ensure an entirely satisfactory result in this respect, the
mixture obtained is transferred to a mechanical mixing machine, in which its
temperature is maintained while its ingredients are being thoroughly incorporated
together. A machine having a pair of steam heated rollers (by preference
revolving at differential speeds) between which the mixture is passed is found to
answer the purpose well. Below the rollers there may be a steam heated tray to
catch the droppings and keep them in a plastic condition. Other mechanical mixing
devices however may be employed. Sometimes other ingredients may be added to
the shellac and emery if desired, and they also may be heated to any desired
temperature before adinixture. The system of manufacture here described may be
employed also where other gums than shellac, such as gum courie for example, are
used as the binding element either alone or in conjunction with shellac. Hitherto
it has been usual to place the cold shellac into a vessel heated over a furnace, and
to add thereto before it is melted, the emery which has been previously heated over
a furnace to such a temperature that it melts the shellac when mixed along with it.
The temperature to which the emery is thus heated is very irregular and this
circumstance as well as the uncertain degree of temperature at which it has been
practicable to keep the mixing vessel, has rendered the production of good work
very difficult and has sometimes caused the shellac to be spoilt or destroyed by
overheating. The mixing of the ingredients has been done by hand only and in
order to work them together even fairly satisfactorily it has been necessary to add
other substances such as oxide of iron or flour of emery, which, while assisting the
manufacture of the wheels, are prejudicial to their working quality, inasmuch as
they increase their tendency to "glaze." But even with the use of these injurious
ingredients it is found impossible to secure by hand stirring more than an approxi-
mate uniformity in the consistency of the mixture produced, the result being that
while some, wheels are fairly regular in quality, others are so irregular as to be
quite inferior. Under my improved method of manufacture-the use of such
deleterious ingredients is rendered entirely unnecessary, the wheels produced are
much less liable to "glaze "than those made in the usual way, and uniformity in
quality can be ensured.
II. C. CARVER,
Agent for Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in the Manufacture of Emery Wheels.
I, ROBERT LUKE of Lime Bank Works, Ardwick, Manchester in the County of
Lancaster, Engineer, 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 :-
For the manufacture of emery wheels in which shellac is used for binding the
emery, the shellac and the emery are each heated independently to the temperature
best suited to the manufacture, appropriate apparatus being employed in each case
for heating the materials so as to secure regularity in their temperature.
jacketted vessels may be used for this purpose.
Steam
The shellac and the einery having been both heated to the desired temperature
and the shellac being liquified by the heat, the emery is transferred to the vessel
containing the shellac and the two ingredients are partly mixed together by stirring,
the heating of the containing vessel being continued in the meantime. This stirring
process does not however mix the ingredients as intimately as is necessary for
producing thoroughly reliable wheels of uniform quality; and in order to ensure
an entirely satisfactory result in this respect, the mixture obtained is transferred to
a mechanical mixing machine in which the temperature of the ingredients is
artificially maintained at a suitable temperature while they are being thoroughly
incorporated together. A machine having a pair of steam heated rollers (by
preference revolving at differential speeds) between which the mixture is passed is
found to answer the purpose well. Below the rollers there may be a steam heated
tray to catch the droppings and to keep them by its heat in a plastic condition.
Other known mechanical mixing devices may however be employed for the incor-
porating process. Sometimes other ingredients may be added to the shellac and
emery if desired and they also may be heated as described to any desired temperature
before admixture. Hitherto it has been usual to place the cold shellac into a
vessel heated over a furnace and to add thereto before it is melted the emery which
has been previously heated over a furnace to such a temperature that it melts the
shellac when mixed with it. The temperature to which the emery is thus heated
is very irregular and this circumstance as well as the uncertain degree of tempera-
ture at which it has been practicable to keep the mixing vessel has rendered the
production of good work very difficult, and has caused the shellac to be spoilt or
destroyed by overheating. The mixing of the ingredients has been done by hand
only and in order to work them together oven fairly satisfactorily it has been
necessary to add other substances such as oxide of iron or flour of emery which,
while assisting the manufacture of the wheels, are prejudicial to their working
properties, inasmuch as they increase the tendency of the wheels to "glaze." But
even with the use of these injurious ingredients it is found impossible to secure by
hand stirring more than an indifferent uniformity in the consistency of the mixture
produced, the result being that while some wheels are fairly regular in quality,
others are so irregular as to be quite inferior.
Under my improved method of manufacture the use of such deleterious
ingredients as have been referred to is rendered unnecessary, the wheels produced are
much less liable to "glaze" than those made in the usual way, and uniformity in
quality can be ensured.
.!
In order to make the improved method of manufacture more clear a sheet of
drawings is appended to this Specification showing the apparatus which I have
found most suitable for heating and mixing the ingredients.
Figs. 1 and 2 are two views of a steam jacketted pan for beating the
ingredients.
As many of these pans are employed as there are ingredients to be heated
separately. The pan is mounted on trunnions as shewn, the steam entering through

page_text: the pipe 1, and the condensed water issuing through the pipe 2 connected to a
steam trap which is not shewn. Although the mounting of the pans upon trunnions
is a convenience for the discharging of the contents of the pans, it is not essential.
The partial mixing and stirring of the ingredients together as described in one of
the pans may be effected by hand labour.
Fig. 3 and 4 are respectively end and side elevations of a roller mixing machine
for thoroughly incorporating the ingredients together.
This machine comprises two steam heated rollers, 3, 4, rotated at differential
speeds and carried by a frame 5, thus far resembling the mixing machines commonly
employed in india rubber works. Beneath the rollers is a steam heated tray 6
having a jacketted bottom fed with steam through a pipe 7. and provided with a
pipe 8. for carrying off the condensed water to a steam trap which is not shown.
The mixed ingredients are fed to the machine between the rollers at the top side,
the rollers being set slightly apart from each other (not touching as shown in the
drawing) and the more quickly running roller becomes coated with the mixture, the
ingredients of which (under the dragging action resulting from the differential
speeds at which the rollers rotate) gradually become thoroughly and uniformly
incorporated together. Portions of the mixture drop from the rollers on to the
steam heated tray and are from time to time taken out therefrom and put back on
the rollers, being in the meantimo retained in a plastic condition by the heat of the
tray. When the incorporation of the mixture is completed it is removed from the
machine and moulded into wheels in the usual way. The temperature to which
the shellac is heated is (as already stated) such as to liquify it and to enable the
mixing operations to be efficiently performed without injury to its qualities for
binding the emery when made into wheels. The method described for heating the
pans, rollers and tray facilitates the attainment of great uniformity in the operations
of manufacturing the emery wheel compounds, and the action of the rollers produces
great homogeneity in the compounds.
Having now particularly described and ascertained the nature of the inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
The method or process of preparing the compounds for emery wheels having a
shellac bond by heating the several ingredients before they are mixed together
with regularity nud certainty to a suitable constant temperature in respective steami
jacketted pans by partly mixing and stirring together the heated ingredients in the
pan containing the shellac, and by afterwards thoroughly incorporating them one
with another by the action of steam heated rollers revolving at differential speeds
and provided with a steam heated tray for catching the droppings and for retaining
them in a suitably plastic condition until again transferred to the rollers, so as to
obtain emery wheel compounds of great homogeneity and uniformity, substantially
as described.
Dated this Eighth day of April 1892.
H. C. CARVER,
Agent for Applicant.