and for other Purposes.
Year: 1887

page_text: Date of Application, 7th Feb., 1887.
Specification Accepted, 11th Mar., 1887.
and for other Purposes.
I, THOMAS RUDDIMAN JOHNSTON, of Waverley Works, Murrayfield, Edinburgh, in
the County of Midlothian, Printer and Publisher 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 object of this invention is, to secure the better grinding of printing ink, to permit
of the several parts of the ink-mill being easily cleaned, and to reduce the amount of
attendance, at present necessary with the ink mills now in use. This I accomplish by
passing the ink between two concentric surfaces, bearing against each other, one of
which is revolving, and the other stationary, and by which the ink is thoroughly
ground, and falls afterwards into a vessel placed to receive it. The parts between
which the ink is ground, can be easily adjusted to give any desired amount of.
pressure, on the particles of ink, and they also can be completely separated for
cleaning purposes.
With the ink mills at present in most general use, the dry colour is first roughly
mixed with varnish, then placed so as to be carried between two horizontal rollers,
slowly revolving in contact, in different directions, and at different speeds, where it
meets with a crushing and rubbing action, and one of these rollers revolving against a
third, travelling at a quicker speed, conveys the ink to it, still further grinding it, and
this third roller leaves the ink on a scraper, against which it works. It will thus be
seen, that the ink only comes twice under pressure, and for only an instant in each
case, receiving also a slight rubbing action, and that therefore it is necessary for the
attendant to remove it from the scraper, and pass it again and again through the mill,
before a satisfactory result can be obtained. These mills cause also a loss of ink, from
there being no efficient means to prevent it working past the flanges of the rollers, and
it is almost impossible to remove from them all traces of one colour, before grinding
another, thus causing great waste when delicate colours follow those of darker shades.
There are other ink mills grinding the ink between two flat rotating surfaces, but
they do not confine the ink, require much attendance, and are otherwise unsatisfactory.
In my ink mill the ink receives a continuous rubbing action under pressure, as it
travels from the top to the bottom of the ink pot, and by the pressure given to the

page_text: grinder, against the pot, the passage of the ink is controlled, so that any amount of
reduction can be obtained, in one passage of the ink through the mill, and that entirely
without attendance, after the ink is placed in the pot. After the ink is completely
ground, it drops into a vessel placed to receive it, and the grinding surface being
capable of being easily and completely separated, the mill can be quickly and
thoroughly cleansed, without loss of ink.
In the accompanying drawings, Fig. 1 is a side elevation, partly in section, of one
of my ink mills, and Fig. 2 is a plan of part of the same mill. Figs. 3, 4, 5, 6 and 7
are also side elevations of similar ink mills, with their parts arranged in different
ways, and Fig. 8 is a front elevation showing the arrangement of part of the mill when
the grinder is lifted out of the pot, as in Figs. 4 and 5, and Fig. 9 is a diagram of
sections of the grinder shaft, used in these latter cases.
To describe the drawings in detail. Fig. 1 is a side elevation of one of my ink
mills, showing one arrangement of the parts, and Fig. 2 is a plan of part of the same
mill. A is the frame of the machine, and B is the grinder, constantly revolving, when
ink is being ground, in the bottomless pot C. Dry colour and varnish, or ink, being
placed in the pot, the belt is shifted from the slack pulley D, to the fast pulley E, thus
causing the bevelled wheels F and G to revolve, and so convey motion to the grinder B,
which rotating in its pot C, grinds the ink, which slowly passes between its surface
and that of the pot, until it reaches the lowest portion of the sides of the latter, when
it drops into the vessel placed to receive it. To adjust the pressure between the
grinding surfaces, and to permit of the thorough cleaning of all the parts, when inks
of different colours or. natures are being ground, the pot can be raised against the
grinder, or lowered away from it. In Fig. 2, an enlarged plan in section, of part of
the pot and frame, is given, and it shows how the former is secured to the latter, but
capable of having an up or down movement given to it. The dotted line H represents
the largest circumference of the pot, and I a section at the upper, and J a section at
the lower parts of it, where it joins the plate K, working against the frame. This
plate K, having projections L, passing through the frame, can be made to move up
and down in close contact with the face of the latter, and there is on the opposite side
of the frame, and corresponding with, and screwed to K, by means of the bolts M,
another plate N, carrying the eyepieces O and P, through which passes the screw Q,
fixed to the frame at R and S, and incapable of revolving, and which has on it, the
upper and lower jam nuts T and U. To lower or raise the pot it is only necessary to
lower or raise the lower nuts U, and the upper nuts T, keep it securely fixed at any
desired distance from the surface of the grinder, the security of its position being
assisted by the width and height of the supporting plates K and N, and their large
bearing surfaces. In Fig. 1 the dotted lines show the lowest position of the pot. The
lower portion of the frame is arched, the sides being shown at A2, Fig. 2, the screw
and its parts being within the arch.
Figs. 3, 4, 5, 6 and 7 are simply modifications of the above arrangement. In Fig. 4
the grinder both revolves and rises, the pot being constantly stationary. To manage
this, the grinder shaft is as shown also on an enlarged scale in Fig. 9, circular
where it passes through the frame and large bevelled wheel at A1 and A2, eight-
sided As at the large washers A* which work against the frame, and screwed in its
upper and lower portions A³ and Aº, on which the jam nuts A revolve, and square
where it enters the grinder at A*. On the boss of the large bevelled wheel, are two
feathers, working in slots A³, cut in the grinder shaft, thus compelling the grinder to
rotate with the bevelled wheel, but permitting its shaft to slide up or down in the
wheel, when the grinder is being raised or lowered. To increase or decrease the
pressure, the upper or lower nuts are raised or lowered. When the grinder has to be
lifted clear of the pot for cleaning purposes, after placing the belt on the loose pulley,
I unscrew the nuts A' until they rest on the side parts of the frame A 10-see also
Fig. 8- and then place a handle on the end of the cross-shaft A", and revolve it, thus
revolving the bevelled wheels, grinder shaft and grinder, and the screw on the shaft
being forced to work through the nuts A', bearing against the frame by the weight of
the grinder, causes the latter to rise, and it is lowered in a similar manner, the

page_text: slots permitting the shaft to pass the feathers on the large bevelled wheel. In this
design, to steady the mill, the frame separates and spreads outwards in its lower
portion.
In Fig. 5 while the grinder can be raised and lowered only, the pot is made to
revolve, the large bevelled wheel 62 being joined to the lower portion of it, and the pot
resting on small wheels 63, supported on a circular frame b* The grinder is raised
and lowered in a similar manner to that in Fig. 4, but its portion passing through the
frame being square in shape, the lower nuts 65 are revolved, while they rest on the
side parts of the frame bº.
In Fig. 3 the motions are similar generally to those in Fig. 1, but the grinder and
pot are inverted. To clean them, or adjust the pressure in this arrangement, the pot
is raised or lowered above the grinder, in a similar way to that by which in Fig. 1, it
was moved beneath it.
Fig. 6 is similar to Fig. 5, and Fig. 7 to Fig. 4, but having also the grinders and
pots inverted. To raise and lower the grinders in these cases, it is only necessary to
revolve the upper nuts, or in the latter case, to revolve the grinder through the cross-
shaft as in Fig. 4, keeping the upper nuts stationary.
To prevent the friction in Figs. 4 and 7, of the large bevelled wheel, against the
frames, a pin can be passed through its boss and through the grinder shaft, but if used
it must be removed, before the grinder can be raised or lowered, for cleaning
purposes.
Win all the Figs., is the vessel for receiving the ink, as it drops from the mill.
A hopper can be fixed to the frame A, so that a constant supply of ink can be given
to the mill, and thus make all attendance unnecessary.
Though as drawn, the grinder and pot are meant to be of metal, the former being
hollow when of large size, they can also be made of granite, and other substances, and
as the mill may be used for a variety of purposes, the surfaces may be raised or
indented, to form crushing, cutting, scraping, or rubbing surfaces, and where either
the pot or grinder does not revolve, it may be made hollow, or double sided, and so
heated or cooled, by the circulation of hot or cold water through it.
Though I have shown in Figs. 1, 3, 4 and 7 the grinder being driven by pullies,
and bevelled wheels, when the speed will permit it, the former only may be used,
placed directly on the grinder-shaft.
Though I have also only shown the grinder or pot revolving, both may be made to
revolve, either in the same or contrary directions, and at the same or different speeds.
The shapes of the pot and grinder may also be varied, as both can be made flatter,
or of other design, and the former instead of being bottomless, may have only a small
outlet, and the grinder shaped accordingly.
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,
1. The use for grinding purposes, of two concentric surfaces, one in motion, and
the other stationary.
2. The means of adjusting the pressure, between two concentric surfaces, used for
grinding purposes, and of removing the one from the other, for cleaning, as described.
3. The Ink Mills as described.