IMPROVEMENTS IN MILLS FOR GRINDING GRAIN AND OTHER SUBSTANCES
Year: 1877

page_text: LETTERS PATENT to Alexander Melville Clark, of 53, Chancery Lane, in the
County of Middlesex, Patent Agent, for the Invention of "IMPROVEMENTS
IN MILLS FOR GRINDING GRAIN AND OTHER SUBSTANCES." A communication
from abroad by Victor Semonin, of Paris, France.
PROVISIONAL SPECIFICATION left by the said Alexander Melville Clark at
the Office of the Commissioners of Patents on the 13th March 1877.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middle-
sex, Patent Agent. "IMPROVEMENTS IN MILLS FOR GRINDING GRAIN AND OTHER
SUBSTANCES." A communication from abroad by Victor Semonin, of Paris,
France.
This Invention relates to an arrangement of apparatus having for its object to
ease the running stone in horizontal mills when the speed of the mill is either
accelerated or retarded from any cause. Increase of speed is generally due to
deficiency in the feed of grain, and in this event the running stone is liable to race
and grind against the other stone, thereby destroying the dressing of both. De-
crease of speed is due to the choking of the mill, slipping of the driving belt, and
other causes.
This Invention consists in providing on a vertical spindle a loose clutch geared
by any suitable arrangement with the mechanism for regulating the distance
between the stone, and in fitting on the said spindle, above and below the first
clutch, other clutches turning with and sliding on the spindle, and which within
certain limits, that is to say, when the mill is running at or about its normal speed,
are retained out of gear with the loose clutch, but which immediately the speed is
accelerated or retarded beyond the said limit are geared, the one or the other, as
the case may be, with the loose clutch, thereby actuating the mechanism for
regulating the distance of the stones and giving an audible signal by striking a
bell or otherwise.
To actuate the sliding clutches I may employ either, 1st, a centrifugal governor-

page_text: mounted on the vertical spindle and connected with the sliding clutches, so that by
the rising or falling of the governor balls as the speed increases or diminishes the
one or other sliding clutch will be geared with the loose clutch to actuate the
mechanism which regulates the distance of the stones; or, 2ndly, a governor, as
above mentioned, to actuate only one of the sliding clutches when the speed slackens
and the governor balls fall, the other clutch being in this case actuated by the
feed hopper to which the corn is supplied, the said hopper being for this purpose
fitted to slide on the vertical spindle, and supported on springs or equivalent device,
which when the supply of corn runs short raise the hopper and throws the clutch
into gear.
I reserve the option of employing the apparatus without the governor, that is to
say, with the hopper arranged as above to guard only against a deficient supply of
grain, and also against corks, straw, and other foreign matters which might be
amongst the grain or liable to obstruct the working of the mill.
In order that the Invention may be more readily understood I have illustrated
it in the annexed Drawings, in which Figure 1 shows the Invention applied to a
mill with a governor and a moveable hopper to actuate the sliding clutches;
Figure 2 shows the mechanism for regulating the distance between the stones.
On the ryne a, Figure 1, is fixed a metal cap b which serves to connect the
gear with the mill spindle. Upon this cap is fixed the spindle c, at the foot of
which is a cup & serving to distribute the grain to the stones.
e is the governor
fixed to the top of spindle c, and f is the upper sliding clutch turning with
the spindle by a groove and feather connection, and to which the governor
arms are connected; h is the feed hopper, to which the grain to be ground is
supplied by a spout. This hopper terminates at bottom in a pipo i fitting in
another pipe, which conveys the grain to the distributing cup d. Pipe j is
capable of being raised or lowered by a lever p to regulate the supply of grain to the
stones; is the lower clutch supported on a cross bar k fixed to the hopper h, which
is guided in its up-and-down movement by vertical rods n, and rests on springs o
whose tension is capable of being regulated as required; g, m, is a sleeve loose on
spindle c mounted in a bearing 2, and formed with clutches g, m, at its upper and
lower ends to correspond and engage with the clutches f, l. It also has a pinion s
upon it gearing with a spur wheelt keyed on a shaft n, which also serves as a
guide rod for the hopper b, and is geared by means of bevel gear u, v; shaft x
(Figure 1), and bevel gear y,(Figure 2), with a shaft 1, which thus receives rotary
motion from the clutch, and serves in all horizontal mills to regulate the distance
between the stones.
At the upper end of shaft 1 is a hand wheel 2 whereby in all ordinary cases the
distance of the stones is regulated without interfering with the automatic regulator
of this Invention.
This regulation by hand is effected by the following means :-The sleeve 3 to
which wheel 2 is fixed has teeth on its under side which gear with corresponding
teeth cast on a wheel loose on shaft 1. The sleeve 3 is keyed on the shaft, and
when it is in its lowest position it fixes the wheel on shaft 1. To bring the
stones again into work the sleeve 3 is raised by the hand wheel 2 until it abuts
against stop 4, when the wheels remains stationary whilst the shaft 1 and sleeve 3
turn. 5, Figure 1, is a stud on sleeve f, m, which trips the hammer of a bell at
each revolution so long as the sleeve is rotated by either of the clutches f, 7, being
thrown into gear with it by the action of the governor e when the speed slackens,
or of the hopper h when the feed becomes deficient.
The following arrangement allows the governor to remain in the lowered position
whatever speed the mill may subsequently attain, and so keep sounding the bell
until the defect is remedied:-j is a flange on clutch f, which as the latter descends
strikes and depresses a kind of stop 8 that cannot rise again, and which prevents.
the clutch and governor balls being raised by centrifugal action until the stop 8 is.
released by pressing on the catch 9.
.

page_text: To prevent the stones being separated too great a distance the action of the
-pinion is limited by wheel t, having no teeth on a portion of its circumference, so
that wheel t will only be partly rotated. To prevent wheel t rotating too far by its
momentum, spring stops are provided on it which strike other stops on the cross bar r.
In cup & there is a spiral 10 which turns with spindle c, and serves to throw off any
foroign matters that may be contained in the grain.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Alexander Melville Clark in the Great Seal Patent Office on the 11th
September 1877.
ALEXANDER MELVILLE CLARK, of 53, Chancery Lane, in the County of Middle-
sex, Patent Agent. "IMPROVEMENTS IN MILLS FOR GRINDING GRAIN AND OTHER
SUBSTANCES." A communication from abroad by Victor Semonin, of Paris,
France.
This Invention relates to an arrangement of apparatus having for its object to
relieve the running stone in horizontal mills when the speed of the mill is either
accelerated or retarded from any cause. Increase of speed is generally due to the
feed ceasing; as the mill then has no work to perform, the running stone is liable to
race and grind against the other stone, thereby destroying the dressing of both.
Decrease of speed is due to the choking of the mill, slipping of the driving belt, and
other causes.
This Invention consists in providing on a vertical spindle a loose clutch geared
by any suitable arrangement with the mechanism for regulating the distance
between the stones, and in fitting on the said spindle, above and below the first
clutch, other clutches turning with and sliding on the spindle, and which within
certain limits, that is to say, when the mill is running at or about its normal speed,
are retained out of gear with the loose clutch, but which immediately the speed is
accelerated or retarded beyond the said limit are geared, the one or the other, as the
case may be, with the loose clutch, thereby actuating the mechanism for regulating
the distance of the stones, and giving an audible signal by striking a bell or
otherwise.
To actuate the sliding clutches I may employ either, (1) a centrifugal governor
mounted on the vertical spindle and connected with the sliding clutches, so that by
the rising or falling of the governor balls as the speed increases or diminishes the
one or other sliding clutch will be geared with the loose clutch to actuate the
mechanism which regulates the distance between the stones; or, (2) a governor, as
above mentioned, to actuate only one of the sliding clutches when the speed slackens
and the governor balls fall, the other clutch being in this case actuated by the
feed hopper by which the grain is supplied, the said hopper being for this purpose
fitted to slide on the vertical spindle, and supported by springs or equivalent device,
which when the supply of grain runs short raises the hopper and throws the clutch
into gear.
I reserve the option of employing the apparatus without the governor, that is to
say, with the hopper arranged as above mentioned to guard only against a deficient
supply of grain, and also against corks, straw, and other foreign matters which
might be amongst the grain and liable to obstruct the working of the mill.
In order that the Invention may be more readily understood I have illustrated
it in the annexed Drawing, which shows a part sectional elevation of a mill with a
governor and a movable hopper to actuate the clutches.
On the ryne a is fixed a metal cap b which serves to connect the gear with the
mill spindle. Upon this cap is fixed the spindle c, at the foot of which is a cup d,
serving to distribute the grain to the stones; e is the governor fixed to the top of

page_text: the spindle c, and is the upper sliding clutch turning with the spindle by a
groove and feather connection, and to which the governor arms are connected;
his the feed hopper, to which the grain to be ground is supplied by a spout. This
hopper terminates at bottom in a pipe i fitting in another pipe j, which conveys the
grain to the distributing cup d; pipe is capable of being raised or lowered by a
lever P to regulate the supply of grain to the stones; is the lower clutch sup-
ported on a cross bar le fixed to the movable hopper h, which is guided in its up-
and-down movement by vertical rods n, and rests on springs o whose tension is
capable of being regulated as required; g, m, is a sleeve loose on spindle c mounted
in a bearing r, and formed with clutches g, m, at its upper and lower ends to
correspond and engage with the clutches f, . It also has a pinion s upon it gearing
with a spur wheel t keyed on a shaft n, which also serves as one of the guide rods
for the hopper b, and is geared by means of bevel gear u, v, shaft x, and bevel
gear y, z, with a shaft 1, which thus receives rotary motion from the clutch, and
serves in all horizontal mills to regulate the distance between the stones.
At the upper end of shaft 1 is a hand wheel 2, whereby in all ordinary cases the
distance of the stones is regulated without interfering with the automatic regulator
of this Invention.
This regulation by hand is effected by the following means:-The sleeve 3 to
which wheel 2 is fixed has ratchet teeth on its under side, which gear with corre-
sponding teeth cast on a wheel loose on shaft 1. The sleeve 3 is keyed on the
shaft, and when it is in its lowest position it fixes the wheel z on shaft 1. To
regulate the stones by hand the sleeve 3 is raised by the hand wheel 2 until it
abuts against stop 4, when the wheel z remains stationary whilst the shaft 1 and
sleeve 3 are turned.
The automatic working of the apparatus is as follows:-When the supply of
grain in hopper h is deficient the springs o, o, raise the hopper and throw the
clutch into gear with the clutch m, whereby rotary motion is transmitted through
pinions and the other gear before described to shaft 1, from which the screw for
regulating the distance between the stones is operated. 5 is a stud on sleeve g, m,
which trips the hammer of a bell 6 at each revolution to give warning of a
deficiency in the supply of grain or other irregularity, the bell continuing to sound
and the upper stone remaining raised, whatever may be its speed, until the hopper /
is again filled and the stone readjusted in position by the hand wheel 2. The
governor e only comes into action when the speed slackens through the choking of
the mill or the slipping of the belt on the pulley. The governor balls then fall and
throw the clutch finto gear with the clutch g, whereby motion is imparted to the
gear for raising the stone and sounding the bell G.
The following arrangement allows the governor to remain in the lowered position
whatever speed the mill may subsequently attain, and so keep sounding the bell
until the defect is remedied:-7 is a flange on clutch f, which as the latter descends
strikes and depresses a kind of stop 8 that cannot rise again, and which prevents
the clutch fand governor balls being raised by centrifugal action until the stop 8 is
released by pressing on the catch 9.
To prevent the stones being separated too great a distance the action of the
pinions is limited by a wheel t, having no teeth on a portion of its circumference, so
that wheel t will only be partially rotated. To prevent wheel t rotating too far by
its own momentum it is encircled by a steel strap with spring stops provided on
each end which strike other stops on the cross bar r. These stops are by the
action of pinion s-deflected and caused to pass over the stops on cross bar r ; but
immediately the pinion ceases to actuate wheel t they abut against said stops and
arrest the motion of the wheel. In cup d there is a spiral 10, which turns with
spindle c, and serves to intercept any foreign matters that may be contained in the
grain.
Having described the nature of the said Invention and the manner of performing
the same, I declare that what I claim as the Invention to be protected by the
berein-before in part recited Letters Patent is, the employment in horizontal mills

page_text: of an automatic regulator in combination with the ordinary means of adjusting the
stones, constructed and operating substantially as shown and described.
In witness whereof, I, the said Alexander Melville Clark, have hereunto set
my hand and seal, this Eleventh day of September, in the year of our
Lord One thousand eight hundred and seventy-seven.