IMPROVEMENTS IN THE CONSTRUCTION OF SCREENS FOR SCREENING CORN AND OTHER SEEDS " SP
Year: 1882

page_text: *LETTERS PATENT to Robert Boby of Bury St Edmunds in the County of
Suffolk Engineer and Thomas Stevens of the same place, Engineer for an
Invention of "IMPROVEMENTS IN THE CONSTRUCTION OF SCREENS FOR
SCREENING CORN AND OTHER SEEDS
"
PROVISIONAL SPECIFICATION left by the said Robert Boby & Thomas
Stevens at the Office of the Commissioners of Patents on the 29th November
1882.
ROBERT BOBY of Bury St Edmunds in the County of Suffolk Engineer, and
THOMAS STEVENS of the same place, Engineer "IMPROVEMENTS IN THE
CONSTRUCTION OF SCREENS FOR SCREENING CORN AND OTHER SEEDS
"
The chief object of this invention is to improve the construction of the self
acting screen for which a patent was granted to one of the present applicants
bearing date 14th March 1871 N° 676, and to permit of the removal of the grid and
its replacement by a finer or a coarser grid so as to adapt the one machine for
screening various kinds of seeds.
In the specification of the Patent of 1871 the motive power for moving the grid
clearers is described as obtained from a bucket wheel used to feed the grain to the
screening surface.
In the present instance we employ the same contrivance, the bucket wheel
receiving the grain or seed from a fixed hopper, but in this case discharging it onto
a riddle interposed between the wheel and the screen for the purpose of separating
foreign substances of large size from the grain or seed. This riddle we propose to
mount upon springs and to agitate it by means of a reciprocating hammer receiving
its motion from the shaft of the bucket wheel.
The screen which is fixed we provide with two sets of clearers to which a
traverse motion is imparted from the bucket wheel shaft. The clearers consist
by preference of metal discs as heretofore, which project between the longitudinal
wires of the grid and are strung upon transverse bars. The bars which are
arranged in two sets severally project through longitudinal slots formed in the
sides of the grid frame, and they drop respectively into notches formed in the sides
Din Ga1

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of a pair of wheel carriages. These carriages are free to run upon guide rails and
thereby approach to and recede from one another.
For the purpose of imparting to the carriages this movement we fit on to the
opposite ends of the bucket wheel shaft a pair of double armed levers one end of
which we connect by rods to the upper ends of a pair of rock levers pivotted to
the framing of the machine near the middle of the fixed sieve. The lower ends of
these rock levers we connect by rods, to, say, the forward carriage and the upper
ends to the hinder carriage. Mounted on the arms of one of the levers on the
bucket wheel shaft are bowles which are intended to strike against a bell crank
lever connected by a rod with the swinging hammer situate near the riddle and
thereby to agitate the riddle. This arrangement ensures that for every rotation of
the bucket wheel two blows will be struck on the riddle which being elastically
suspended will be kept in agitation during the working of the machine. Thus any
substances retained on the riddle will be caused to work down to its lower end and
fall into a discharge channel arranged transversely of the machine to receive
extraneous matters and deliver them out of the machine..
When it is intended to change the screen for one of coarser or finer gauge the
screen is to be lifted out of the rebates which hold it in place together with the
clearers with which it is fitted. Another screen with its clearers is then to be
inserted, the clearer bars will then drop into the notches of the reciprocating wheel
carriages and no further coupling up of the parts will be required,

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Robert Boby & Thomas Stevens in the Great Seal Patent Office
on the 29th May 1883.
ROBERT BOBY of Bury Saint Edmunds in the County of Suffolk, Engineer
and THOMAS STEVENS of the same place, Engineer "IMPROVEMENTS IN THE
CONSTRUCTION OF SCREENS FOR SCREENING CORN AND OTHER SEEDS "
The chief object of this Invention is to improve the construction of the self
acting screen for which a Patent was granted to one of the present applicants
bearing date fourteenth March One thousand eight hundred and seventyone,
N° 676, and to permit of the removal of the grid or screen, and its replacement by
a finer or a coarser grid, so as to adapt the one machine for screening various kinds
of seeds. In the Specification of the Patent of One thousand eight hundred and
seventyone a fixed grid was employed with travelling disc clearers, but these
did not admit of removal from the machine. The motive power for actuating
the grid clearers was described as obtained from a bucket wheel used to
feed the grain to the screening surface. In the present instance we employ
the same contrivance, the bucket wheel receiving the grain or seed from a
fixed hopper, but in this case discharging it on to a riddle interposed between the
wheel and the screen or grid for the purpose of separating foreign substances
of large size from the grain or seed. This riddle we mount on an elastic support,
and agitate by a tappet action to ensure its efficiency.
In the accompanying drawings Fig. 1 is a side elevation of our improved corn
screen. Fig: 2 is a partial side section, Fig: 3 a transverse vertical section of the
same, and Fig: 4 is a cross section of one of the clearer carriages, shewing in place
the screen acted upon by the clearers.
A A is the framing of the machine carrying a hopper B, which extends
across from one side frame to the other, and delivers corn along its whole
length to a rotating bucket wheel C, as in the Patent above mentioned.
The seed, as it falls from the bucket wheel, is received on to a riddle D, seen
best in Fig: 2. Through this riddle it passes onto the grid E which is fitted
with two sets of travelling clearers F F, mounted in their respective wheel
carriages G, G, to which a traverse motion is imparted from the bucket wheel
shaft. The clearers F consist by preference of metal discs as heretofore, which
project between the longitudinal wires of the grid, and are strung upon transverse
rods. These rods, which are arranged in two sets, severally project through
longitudinal slots formed in the sides of the grid frame and drop respectively into
notches formed in the sides of the carriages G G.-The carriages G are free to run
upon guide rails G their wheels being flanged for that purpose, and they are
caused to approach to and recede from one another, so as to impart a traverse motion
to the disc clearers and cause them to remove any matters that may adhere to the
grid or screen.
For the purpose of imparting to the carriages this movement, we fit on to the
opposite ends of the bucket wheel shaft, a pair of double armed levers C', one end of
which we connect by rods C' to the upper ends of a pair of rock levers C³ pivotted
to the framing of the machine near the middle of the length of the fixed grid. The
lower limb of these rock levers we connect by rods C to say, the binder carriage,
and the upper limb to the forward carriage.
Mounted on the arms of one of the levers C₁ of the bucket wheel shaft. are two
bowles c. which are intended to strike against a rock lever H pivotted on the main
framing. This rock lever is connected by a rod H¹ with the arm H³ of a transverse

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rock shaft H mounted in bearings in the side frames. This rock shaft carries a
pair of hammers H which are intended to strike on the frame of the riddle D, and
thereby to keep the riddle in agitation while the machine is in action. For this
purpose the hammers are mounted elastically on their rock shaft, and the riddle,
which rests at its rear on a supporting bar, is carried at its forward end by an
adjustable bracket pendent from an ash wood spring D¹ extending across the
machine, and made fast to the side frames.
At the front end of the riddle a trough shaped shute D' is fixed for the purpose
of receiving the foreign substances of large size discharged on to the riddle, and
delivering the same out of the machine.
By the use of the tappet action above described, it will be understood that for
every rotation of the bucket wheel, two blows will be struck upon the riddle, which
being elastically suspended, will be kept in agitation during the working of the
machine. Thus any substances retained on the riddle will be caused to work down
to its lower end, and fall into the trough-shaped shute D' and be delivered
therefrom out of the machine, while the grain falling through the riddle will be
received onto the grid or screen below.
When it is intended to change the screen or grid E for one of coarser or finer
gauge, it is to be lifted by its handles out of the rebates in the crossbars of
the frame in which its extremities rest, together with the clearers with which it
is fitted.
Another screen with its clearers is then to be inserted in place of that removed
from the machine, and the rods of the clearers will then drop into the notches of
their respective reciprocating wheel carriages, and no further coupling up of the
parts will be required.
Having now set forth the nature of our Invention for "Improvements in the
construction of screens for screening corn and other seeds" and explained the
manner of carrying the same into effect we wish it to be understood that under
the above in part recited Letters Patent We claim
First: The application to corn screens of the detachable grid and clearers
arranged substantially in the manner and for the purpose above set forth.
Secondly: The application to corn screens provided with a removable grid and
travelling clearers, of a riddle mounted and operated substantially in the manner
above described.
In witness whereof I the said Thomas Stevens have hereunto set my hand
and seal the twenty-fifth day of May in the year of our Lord One thousand
eight hundred and eighty three.