AN IMPROVED CONSTRUCTION OF BARK MILL
Year: 1878

page_text: LETTERS PATENT to Edward Vavasour, Brown, of Exeter, in the County of
Devon, Engineer, for the Invention of "AN IMPROVED CONSTRUCTION OF BARK
MILL."
Sealed the 4th October 1878, and dated the 6th July 1878.
}
PROVISIONAL SPECIFICATION left by the said Edward Vavasour Brown'
at the Office of the Commissioners of Patents on the 6th July 1878.
EDWARD VAVASOUR BROWN, of Exeter, in the County of Devon, Engineer.
AN IMPROVED CONSTRUCTION OF BARK MILL."
"
This Invention relates to a novel arrangement of mechanism whereby in one
self-contained machine the material intended to be ground is first reduced by a
breaking or tearing action, and then delivered between the grinding surfaces, which
completes the disintegrating process.
The machine consists of a pair of crushing or breaking rolls and a grinding mill
so arranged with respect to each other that the bark or other material submitted
to the action of the machine will, as it leaves the rolls, fall between the grinding
surfaces of the mill, which will reduce it to the state required by the tanner.
The crushing rolls, which are by preference composed of toothed discs of metal
carried by horizontal shafts and spaced out to receive clearers between them, are
placed directly upon the mill core, and slightly upon one side thereof to allow of
the central vertical shaft passing up clear of breaker. The upper end of this shaft
has its bearings in a bridge or bracket casing, which is (preferably) bolted at each
end to the side frame of the breaker, or is carried on cylinder or on floor on separate.
stands. This bridge also acts as a support for the pedestals or bearings for the
pinion shaft driving the mill and cutters, and likewise serves to carry the cleaners
or "pickers" for the near roll, those from the other roll being carried by a bar or
stay casting thrown across the breaker frame.
"
"
The grinding mill is driven from the main shaft by a bevil pinion gearing into a
bevil wheel on the vertical shaft of the mill, and on the driving shaft is also a spur
pinion, which gears into a spur wheel on the axle of the near breaker roll. A pair
of spur pinions on the axles of the breaker rolls serve to gear these rolls together.
A feed plate is provided for guiding the material to the breaking rolls.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Vavasour Brown in the Great Seal Patent Office on the
6th January 1879.
EDWARD VAVASOUR BROWN, of Exeter, in the County of Devon, Engineer.
"AN IMPROVED CONSTRUCTION OF BARK MILL."
This Invention relates to a novel arrangement of mechanism, whereby in one
self-conained machine the material intended to be ground is first reduced by a
breaking or tearing action, and then delivered between the grinding surfaces, which
complete the disintegrating process.
The machine consists of a pair of crushing or breaking rolls and a grinding mill
so arranged with respect to each other that the bark or other material submitted
to the action of the machine will, as it leaves the rolls, fall between the grinding
surfaces of the mill, which will reduce it to the state required by the tanner.
In the accompanying Drawing Fig. 1 shews my improved bark mill in side
elevation, Fig. 2 is a sectional elevation, and Fig. 3 is a front elevation of the
same.
In these Figures A is a conical case of cast iron having grinding teeth on its
inner periphery, and fitted with the rotating cone B, as usual. This casing con-
stitutes the base of the mill, and forms a support for cast-iron cheeks A¹, which
carry the bearings for the crushing rollers C, C. These rolls are by preference
composed of toothed discs of metal strung upon horizontal shafts, and spaced out
to receive clearers c, c, between them. They are so situated with respect to the
grinding portion of the mill as to allow of the central vertical shaft B¹ of the
oone B passing up clear of these rolls. The upper end of the shaft B' has its top
bearing in a bridge A2 bolted at each end to the side cheeks A¹, and its lower end
rests in a step bearing in a casting A³ bolted to the base flange of the case A. The
bridge casting A² serves also as a support for the bearings of the driving shaft D of
the mill, which shaft is fitted with fast and loose belt pullies D¹. The clearers or
pickers C for the breaking rolls C are carried by cross bars A* bolted to the
cheeks A¹
The shaft B¹ of the toothed cone B is driven from the main shaft by a bevil
pinion gearing into a bevil wheel b on the vertical shaft B₁ of the mill, and
on the driving shaft is also a spur pinion d', which gears with a spur wheel c' on
the axle of the near breaker roll,
A feed plate or hopper is provided at E for guiding the material to the breaking
rolls.
As therefore the material is delivered from this table or hopper it will come
under the breaking or tearing action of the rollers C, C, and falling from these
rollers in a partially disintegrated state, it will come under the action of the conical
grinding surfaces, which will complete its reduction to a state fit for use by
the tanner. By thus combining two distinct operations in one machine an
economical. result is obtained, both in respect to cost of plant and space occupied
by machinery.
Having now set forth the nature of my Invention of "An Improved Construction
of Bark Mill," and explained the manner of carrying the same into effect, I wish
it to be understood that under the above in part recited Letters Patent I claim,
combining in one self-contained machine tearing or breaking rolls and grinding
surfaces arranged relatively to each other, as shewn in the Drawing, and receiving

page_text: rotary motion through gearing directly from one common shaft, as and for the
purpose above described.
In witness whereof, I, the said Edward Vavasour Brown, have hereunto set
my hand and seal, the Fourth day of January, in the year of our Lord
One thousand eight hundred and seventy-nine.
EDWARD VAVASOUR BROWN. (L.S.)