IMPROVEMENTS IN GRINDING MILLS
Year: 1882

page_text: LETTERS PATENT to Herbert John Haddan, of Kensington, Middlesex for an
Invention of IMPROVEMENTS IN GRINDING MILLS A communication to him
from abroad by Edmund Schmeja, of Biala-Bielitz, in Austria-Hungary.
PROVISIONAL SPECIFICATION left by the said Herbert John Haddan at
the Office of the Commissioners of Patents on the 18th October. 1882.
IMPROVEMENTS IN
HERBERT JOHN HADDAN, of Kensington, Middlesex,
GRINDING-MILLS a communication to me from abroad by Edmund Schmeja of
Biala Bielitz, in Austria-Hungary.
This invention relates more particularly to disc-grinding mills, but is partly
applicable to other forms of mills or disintegrators. It consists first in separating
the feed chamber or space from which the raw material is supplied to the discs,
from the chamber in which the latter are situated by a moveable slide, so that by
closing the slide the material which has already entered the grinding chamber
may be rapidly ground fine. Also in providing a stirring device in the feed
chamber in front of the moveable slide for the purpose of securing a regular and
continuous supply of raw-material to the grinding chamber. This device may be a
toothed ring mounted on the horizontal shaft of the moveable disc, or a series of
sharp edged steel teeth cast in one piece with a conical collar and working in
conjunction with two toothed stationary plates, or a number of pins or arms may
be driven radially through the enlarged portion of the driving axle situated in the
supply chamber.
In the two latter cases the teeth serve also for the preliminary breaking of the
raw material.
Also in making the casing which encloses the grinding discs in two parts, the
outer one of which is hinged to the stationary part, or fixed thereto by hinged
bolts which pass through slotted flanges, for the purpose of easy inspection and
repairs.
Also in adjusting the position of the two grinding discs against each other, and
thereby the fineness of the product by fixing the rotary disc on its shaft, guiding
the latter by two bushed bearings and placing between the latter a handwheel

page_text: whose hub forms a nut fitting on the screw-threaded extremity of one of the
bushes, while another portion of the hub is so held between washers or collars on
the shaft that any motion of the hand-wheel in the direction of the shaft is
transmitted to the latter. Or the rotary disc may be attached to the shaft by a
groove and feather only, and the handwheel mounted on a spindle screwed into a
boss in front of the lid which closes the grinding spaco, the end of the said spindle
pressing against a disc fitted to the front end of the hub of the moveable grinding.
disc. For minute adjustments the circumference of the handwheel is toothed and
held in position by one of two parallel clicks or ratchets. To prevent the
accumulation of ground material the circumference of the rotary disc is provided
with an arm which extends over the circumference of the fixed disc and
revolves in the space formed between the circumference of the discs and the
casing.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Herbert John Haddan in the Great Seal Patent Office on the
18th. April 1883.
HERBERT JOHN HADDAN of Kensington, Middlesex "IMPROVEMENTS IN
GRINDING-MILLS," a communication to me from abroad by Edmund Schmeja of
Biala-Bielitz, in Austria-Hungary
P This invention relates to rough grinding mills and more particularly to disc
grinding mills, and it consists chiefly in separating the feed chamber or space from
which the raw material is supplied to the discs, from the chamber in which the
dises are situated by means of a partition A and a movable slide B, (see Figs 1..
2. 5. 6. 7. 8. 9. 11.), placed in proximity to the grinding discs in such a manner that
by closing the said slide the material which has already entered the grinding space
may be rapidly ground fine.
For the purpose of causing the raw material to enter regularly from the feed
chamber into the grinding space, even if the slide is only partly opened, the raw,
material in the feed chamber, and particularly when in immediate proximity of the
movable slide, should be continually stirred.
For this purpose a movable collar provided with a nose or tooth C is mounted
on the shaft of the grinding disc in the interior of the feed chamber, which collar
by turning with the shaft continually stirs the raw material.
The same result may be obtained, if, instead of a collar provided with a tooth,
the shaft is perforated by a pin.
For grinding raw material of large size, however, the feed chamber is somewhat
enlarged near the slide, and a disintegrator D.made of cast steel and provided with
strong teeth (see figs 8. 10. 11. 12), is placed near the slide. This disintegrator
may be keyed on the rotating shaft. The teeth of this disintegrator engage in the
teeth of adjustable disintegrating plates F bolted to the casing (see figs 9. 10. 11.)
which arrangement allows of an easy adjustment of the whole disintegrating
device
If required, the pitch of the disintegrating teeth may be made wider towards
the bearing and closer towards the grinding discs, in which case the raw material
is first conducted between the coarser teeth, from where (owing to the pressure of
the feed) it passes through the finer teeth to reach the grinding discs.
It will be observed, that, with the application of a disintegrating device, the
tooth C is sufficiently replaced by the teeth of the rotating disintegrator mounted
on the shaft, and that a disintegrating apparatus of the above described construction
insures a complete and regular feed of the material to the discs, in proportion to
the extent to which the movable slide is opened.
The disintegrating device mounted on the shaft may, according to circum-
stances, be replaced by steel pins or teeth E going through the shaft as shown in
fig. 12.
In mills intended for grinding very hard material a fly wheel is mounted on the
rotating shaft in addition to the conveying disc or toothed wheel, which fly wheel
has for its object to overcome sudden resistances in the disintegrating chamber.
The movable slide mentioned above is provided with a handle H, fig 5, by means
of which the slide may be opened or closed to the extent required.
A further improvement, applicable in various modifications, has for its object a
simple and easy access to the grinding discs. For this purpose the grinding
chamber proper is enclosed by a casing K pivoting on the hinge joint J and
secured by nut L (figs. 2. 4) or this casing is secured by means of several screws..

page_text: as shown in fig. 3 and may be altogether removed from the mill after slackening
the screws.
In mills provided with a disintegrating apparatus in the feed chamber, where
considerable vibrations might occur owing to the great distance of the bearing for
the disintegrating mechanism from the grinding discs, the above described casing
or hood which serves to enclose the grinding chamber is provided with a bearing
for the rotating shaft. In this case the hood or casing is not hinged to the
chamber but fastened by means of a number of screws M (Figs 8 and 10), the
nuts of which are slackened when the cover is to be removed for the purpose of
laying bare the discs.
When the nuts of the screws M are slackened, the screws which pivot in a hinge
joint, may be turned back figs. 9, 10.
For the purpose of adjusting the position of the two grinding discs O and P
towards each other during the working of the mill, by means of which adjustment
the degree of fineness of the grinding can be determined, the rotary grinding
disc is secured on the shaft Q in such a manner that it shares the axial motion
of the shaft, as may be seen in Fig. 7, or the rotary grinding disc O is made
adjustable by groove and feather, on the shaft fixed to its bearings, as shown in
figs. 1 and 8.
i
On this adjustable rotary grinding disc depends the fineness of the grist.
If the rotary disc is to be adjusted together with the shaft, this may be carried
out by means of a hand wheel which has a tapped hub and which may be screwed
to and fro on a stationary sleeve fixed to the bearing as shown in Fig. 7.
In this figure the shaft is provided with two pins S S, by means of which the
shaft is moved forward or backward on turning the hand wheel, whereby the
rotary disc O fixed on said shaft is approached to or removed from the stationary
disc Psituated in the grinding chamber.
The rotary disc O may be made adjustable on the shaft by means of an adjusting
screw spindle U (fig. 1) provided at one end with a click wheel W while the other
end is hardened and presses against a steel plate V mounted on the rotary disc.
Or the hub of the click wheel may be screwed into the bearing and press against
the movable bushing X which again presses against the adjustable disc O whereby
the grinding discs are caused to approach each other, as seen in Fig. 8.
On releasing the click wheel, that is to say, on turning it in the opposite
direction, the discs are automatically removed from each other by the pressure
of the raw material, whereby a rougher grinding is obtained.
Further improvements the object of which is to facilitate the manufacture of
grinding discs, while they are of great consequence for the fineness and equality
of the ground material, consist in the following:
The discs O, P Fig. 13 which are toothed on both sides and may be turned, if
one side is worn out, no longer rest on the grinding teeth or edges as hitherto,
but are provided on the outer and inner circumference with rims a-a, (figs. 13.
14.15 sheet III) serving to support or hold the grinding discs.
To prevent any displacement of the discs the disc holders O', Os are also
furnished with ring shaped projections b―b.
This arrangement has the advantage that the grinding discs may be made of
several pieces having the shape of segments d, fig. 14 sheet III which owing
to the said projections or Hanges b-b, are secured against any accidental
displacement.
-
For the purpose of an easy and continuous lubrication the spindle U is
perforated, so as to admit oil from the oil chamber to the contact plate V.
If adjusting spindles with coarser screw-threads are used, which are less subject
to wear in consequence of repeated adjustment, the too large displacement of
the grinding discs resulting from largo screw threads may be avoided by the
application of two or more clicks Y engaging into the teeth of the click-wheel,
so as to permit an adjustment to the extent of one half or one third of the
interstice between two teeth.