IMPROVEMENTS IN APPARATUS FOR BRUSHING THE SURFACES OF POLYGONAL BOLTING OR DRESSING MACHINES
Year: 1881

page_text: LETTERS PATENT to Frederic Stansfield, of Bradford, in the County of York,
Corn Miller, for an Invention of "IMPROVEMENTS IN APPARATUS FOR BRUSHING
THE SURFACES OF POLYGONAL BOLTING OR DRESSING MACHINES."
PROVISIONAL SPECIFICATION left by the said Frederic Stansfield at
the Office of the Commissioners of Patents on the 12th October 1881.
FREDERIC STANSFIELD, of Bradford, in the County of York, Corn Miller.
"IMPROVEMENTS IN APPARATUS FOR BRUSHING THE SURFACES OF POLYGONAL
BOLTING OR DRESSING MACHINES."
In the bolting or dressing machines used for dressing flour or other pulverulent
substances, it is necessary from time to time to clear off the particles adhering to
the porous fabric through which the fine powder has to pass. When the machines
have cylindrical cages or reels, this is readily effected by applying brushes, but in
cases where the reel is of polygonal form, when brushes are employed as they are
at present arranged, it is necessary to give them a radial movement to and from
the axis of the reel so that they may accommodate themselves to the flat side
successively presented to them. My Invention relates to means of applying
revolving brushes to polygonal reels in such a manner that without moving
radially they accommodate themselves to the surfaces that are to be brushed. For
this purpose I fix on an axis parallel to the axis of the reel brushes which are
made of such radius and caused to revolve at such velocity relatively to that of
the reel, that they bear against and rub over with uniform or nearly uniform
pressure the principal part of the flat polygonal surfaces presented to them on the
reel. For example, assuming the reel to be of octagonal section having a radius at
Price 621

page_text: its angles of 1, if the brush be made with a radius of 0.532 on an axis at a distance
of 1.450 from the axis of the reel, and if the brush be driven in the same direction
as the reel at a speed relatively to that of the reel in the proportion of 8 to 3, the
brush will sweep over with uniform or almost uniform pressure every third face of
the octagon; thus in every 3 revolutions of the reel all its surfaces will be cleared
by the one brush. By fixing 3 brushes on the one axis, or by arranging brushes
on separate axes, all the faces of the reel may be cleared in every revolution
thereof.
In a similar manner by suitably proportioning the radius and speed of the brush
to that of the reel, the faces of polygons of other numbers of sides can be effectually
cleared in the manner described.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Frederic Stansfield in the Great Seal Patent Office on the 24th March
1882.
FREDERIC STANSFIELD, of Bradford, in the County of York, Corn Miller.
"IMPROVEMENTS IN APPARATUS FOR BRUSHING THE SURFACES OF POLYGONAL
BOLTING OR DRESSING MACHINES."
In bolting or dressing machines used for dressing flour or other pulverulent
substances, it is necessary from time to time to clear off the particles adhering to
the porous fabric through which the fine powder has to pass. When the machines
have cylindrical cages or reels, this is readily effected by applying brushes, but in
cases where the reel is of polygonal form, when brushes are employed as they are
at present arranged, it is necessary to give them a radial movement to and from
the axis of the reel so that they may accommodate themselves to the flat sides
successively presented to them. My Invention relates to means of applying
revolving brushes to polygonal reels in such a manner that without moving radially
they accommodate themselves to the surfaces that are to be brushed. For this
purpose I fix on an axis parallel to the axis of the reel brushes which are made of
such radius and caused to revolve at such velocity relatively to that of the reel
that they bear against and rub over with uniform or nearly uniform pressure the
principal part of the flat polygonal surfaces presented to them on the reel. The
polygons employed for bolting or dressing machines are mostly regular hexagons
or regular octagons; I will therefore describe applications of my Invention to these
figures as examples of the method that may be followed in applying it to polygons
of other forms.
Referring to the accompanying diagrams and Figures, Fig. 1 is a diagram
shewing the application of a revolving brush to a hexagonal frame, and Fig. 2 is a
diagram shewing its application to an octagonal frame. In both diagrams the
same letters of reference are employed to indicate corresponding points, A being
the centre of the polygonal frame, and H being the centre around which the brush
is to revolve; I describe the circular axes BC and EJ intersecting at K, and
join A K and HK. Now assuming the polygon and the brush to be revolving in
the direction of the arrows, the velocity of the brush is to be such relatively to
that of the polygon that the point of the brush will travel from E to K in the
same time as the angle of the polygon travels from B to K. As the angle EHK
is travelled through by the brush in the time that the angle BAK is travelled
through by the polygon, the angular velocity or number of revolutions of the brush
per minute should be to that of the polygon in the proportion of the angle EHK
to the angle BAK. By following the setting out shewn in Figs. 1 and 2, the
brush will obviously be made to touch the side of the polygon at the two angles B
and B', and at the middle E. Taking a point 6 halfway between B and K, and a
corresponding point b' such that B¹¹ is equal to Bb, and joining bb¹, this line
will shew the position of the side of the polygon midway in its movement over the
are B K. Taking also the point k midway in the arc EK, this point will be that
of the brush at the same moment that the side of the polygon is in the position
bb. It will be seen that if k does not absolutely coincide with the point where
bb' intersects the circular arc EK, it is so near to it that the deviation is imper-
ceptible; and if the other positions of the side of the polygon and corresponding
positions of the brush be taken, it will be found that the point of the brush is
always nearly coincident with the side of the polygon, so that the brush having a
certain elasticity will practically bear against and rub over the whole side of the
polygon with approximately uniform pressure. In what has preceded I have

page_text: assumed the point I representing the axis of the brush to be taken anywhere, and
shewn how the angular velocity of the brush relatively to that of the polygon is
to be determined. As however it is necessary that the brush after leaving one
side of the polygon should perform the clear part of its revolution when it is away
from the polygon in such time that it will again similarly meet and brush another
side of the polygon, the ratio of the two velocities must obviously be a simple and
commensurable one. In the case of the hexagon Fig. 1, a convenient ratio of the
angular velocity of the brush to that of the polygon is that of 3 to 1, consequently
the point is to be determined such that the angle EHK is three times the
angle BAK. As the whole angle BAE is 30°, taking KA E=13° 20', conse-
quently BAK=16° 40' H must be such that EH K=50° or 3 times 16° 40'. It
will be found by setting out or computation that the distance AH of the brush
spindle from the centre of the hexagon is to the angular radius A B as 1.166 is to 1
very nearly, the brush will then pass over every alternate side of the hexagon,
missing the intermediate sides; but by fixing two brushes opposite to each other
on the axis H, every side of the hexagon will be brushed during each revolution.
In the case of the octagon, Fig. 2, the relative speeds of the polygon and the brush
are conveniently taken in the proportion of 3 to 8, in this case the whole angle
BAE being 22° 30', if K AE be 13° and therefore BAK=9° 30', H is to be
taken such that EHK is 25° 20', to which BAK=9° 30' is in the proportion of
3 to 8. It will be found that in this case A H is to A B in the proportion of about
1.45 to 1, the brush will then pass over every third side of the octagon, always
missing two intermediate sides; all the eight sides however will be brushed in
their turn during 3 revolutions of the octagon, or 8 revolutions of the brush.
Should it be desired to brush all the sides in every revolution of the octagon, three
brushes may be fixed on the axis H equally spaced around it. The brush spindle H
may be driven by a chain passing over chain wheels suitably proportioned, as
shewn at Fig. 3, for the hexagon frame, or by toothed gearing with an intermediate
wheel, as shewn, for the octagon frame at Fig. 4; or it may be driven by other
suitable gear. Also instead of employing only one spindle H with its brush or
sets of brushes, several such spindles might be arranged around the polygon, the
sides of which might thus be repeatedly brushed during each revolution.
Having thus described the nature of my Invention, and in what manner the
same is to be performed, I claim,―
First. The herein described method of brushing the surfaces of a polygonal
bolting or dressing machine by means of a brush fixed on a spindle parallel to the
axis of the revolving polygon, the said spindle being situated at such distance
from the axis of the polygon, and being caused to revolve at a speed so pro-
portioned to that of the polygon and in the same direction that the point of
the brush which the spindle carries travels over the surface of the side of the
polygon.
Second. In combination with a polygonal bolting or dressing frame, a spindle
parallel to its axis carrying a brush or brushes, and connected by suitable gearing
to the revolving polygon, substantially as and for the purposes set forth.
In witness whereof, I, the said Frederic Stansfield, have hereunto set my
hand and seal, this Twenty-first day of March, in the year of our Lord One
thousand eight hundred and eighty two.