IMPROVEMENTS IN ROTATORY SCREENS, AND IN LETTERS
Year: 1863

page_text: LETTERS PATENT to William Nalder, of Challow Works, Wantage, in
the County of Berks, Engineer and Agricultural Implement Manufac-
turer, for the Invention of "IMPROVEMENTS IN ROTATORY SCREENS, AND IN
LETTERS PATENT to William Nalder, of Challow Works, Wantage, in
the County of Berks, Engineer and Agricultural Implement Manufac-
turer, for the Invention of "IMPROVEMENTS IN ROTATORY SCREENS, AND IN
THE MACHINERY OR APPARATUS EMPLOYED IN THE MANUFACTURE OF SUCH
SCREENS."
Sealed the 10th August 1863, and dated the 16th February 1863.
PROVISIONAL SPECIFICATION left by the said William Nalder at the
Office of the Commissioners of Patents, with his Petition, on the 16th
February 1863.
I, WILLIAM NALDER, of Challow Works, Wantage, in the County of Berks,
Engineer and Agricultural Implement Manufacturer, do hereby declare the
nature of the said Invention for "IMPROVEMENTS IN ROTATORY SCREENS, AND IN
THE MACHINERY OR APPARATUS EMPLOYED IN THE MANUFACTURE OF BUCH SCREENS,"
to be as follows:-
This Invention relates, firstly, to an improved construction of rotatory inclined
screen, whether of a cylindrical or polygonal section, and consists in the intro-
duction into the interior of the screen of a metal or other cylinder or drum
extending either entirely or partly along the length of the screen. This internal
cylinder is carried by the spindle of the screen, and revolves with it; it is closed

page_text: at its upper end, and is of smaller diameter than the interior of the screen, so
as to leave an annular space of convenient width between it and the screen
to allow of the passage of the corn or other substances to be screened. The
object of this internal cylinder or drum is to prevent the corn or other sub-
stances from being unduly agitated by the rotation of the screen, and to keep
it down upon the screening surface. It is adjustable on the spindle so as to
be capable of being shifted to any desired portion of the length of the screen.
The second part of my Invention relates to certain peculiar constructions,
arrangements, and combinations of machinery or apparatus for manufacturing
cylindrical or polygonal rotatory screens of wire of any section, or other suitable
material, whereby considerable economy in their manufacture is obtained with
a better and more perfect article. According to this part of my Invention I
propose to form the shoulders on the ends of the longitudinal supports for the
wires by the aid of a machine provided with a traversing cutter or cutters,
which act upon the ends of the wire, and reduce them to the proper size so
as to form a shoulder thereon. The wire to be acted upon is held firmly in
a tubular holder revolving in fixed bearings, and driven by pullies, gearing, or
otherwise, so as to impart a rotatory motion to the wire. The length of the
tubo depends upon the distance required between the shoulders, and a cutter
may be made to act upon each end simultaneously. The several longitudinal
wires or supports having been thus shouldered, are ready for the construction
of the framing or cage of the screen. The next operation is the cutting in a
spiral or helical direction a series of nicks or notches in the several longi-
tudinal wires or supporting bars for the reception of the wire, or other suitable
material intended to form the screening surface of the screen. The pitch or
distance between these nicks or notches depends upon the size of the meshes
or openings of the screen. In cutting these nicks or notches the frame or
cage of the screen is, according to one modification, secured to a spindle or shaft
having a screw thread formed upon it, working in a fixed nut, the whole being
supported in suitable bearings or standards. The pitch of this screw must
correspond with the pitch of the nicks or notches to be produced, consequently
by changing the screw spindle for one of a larger or finer pitch screens of
different sizes of meshes or openings can be made in the same machine.
The nicks or notches are cut by means of a circular saw carried on a spindle
parallel to the cage, Inside the cage there is a metal ring having notches in
its periphery, into which notches fit the longitudinal bars to be nicked, the
ring serving to hold the bars firmly and steadily whilst under the action o
the saw.
An outer stationary ring having a smooth internal surface bear

page_text: upon the outer edges of the bars, and keeps them down upon the inner ring,
the bars being thus held steadily between the inner and outer rings. The
inner ring receives a rotatory motion from a spur pinion or pinions gearing
into teeth on the ring, the rotation of the inner ring carrying the cage or
frame round with it so as to bring the several longitudinal supporting bars
successively under the action of the saw. This rotation of the cage or frame,
and of its carrying spindle causes a longitudinal traverse to be also imparted
to the cage by reason of the screw thread of the spindle working in the fixed
nut, consequently the nicks or notches will be made in a spiral or helical
direction, and of the same pitch as the screw on the spindle. The inner ring
has no lateral motion, not being connected with the screw spindle.
According to another modification the longitudinal traverse may be imparted
to the saw in lieu of to the cylinder by making a screw thread on the saw
spindle, and causing it to work in a fixed nut. In this case the supporting
spindle or shaft of the screen will have no thread upon it. The wire or other
suitable material is now wound on to the cage or frame, being laid into the
nicks or notches already made in the longitudinal bars, and the screen is
completed by hammering down the edges of the nicks or notches over the
coils of wire or other suitable material, so as to hold each coil firmly in its
place. In order to support and steady the bars during the hammering of tho
nicks or notches, a grooved metal block or anvil is held against their inner
sides by a spring or other equivalent contrivance, thus leaving both hands of
the workman at liberty.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Nalder in the Great Seal Patent Office on the
15th August 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
NALDER, of Challow Works, Wantage, in the County of Berks, Engineer and
Agricultural Implement Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixteenth day of February, in the year of
our Lord One thousand eight hundred and sixty-three, in the twenty-sixth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said William Nalder, Her special license that I, the
said William Nalder, my executors, administrators, and assigns, or such

page_text: others as I, the said William Nalder my executors administrators, or
assigns, should at any time agree with, and no others, from time to time
and at all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United Kingdom
of Great Britain and Ireland, the Channel Islands, and Isle of Man, an
Invention for "IMPROVEMENTS IN ROTATORY SCREENS, AND IN THE MACHINERY OR
APPARATUS EMPLOYED IN THE MANUFACTURE OF SUCH SCREENS," upon the con-
dition (amongst others) that I, the said William Nalder, my executors or
administrators, by an instrument in writing under my hand and seal, or under
the hand and seal of one of them, should particularly describe and ascertain
the nature of the said Invention, and in what manner the same was to
be performed, and cause the same to be filed in the Great Seal Patent
Office within six calendar months next and immediately after the date of the
said Letters Patent.
NOW KNOW YE, that I, the said William Nalder, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the accompanying Drawings, and to the
letters and figures marked thereon, that is to say :-
My said Invention relates, firstly, to an improved construction of rotatory
inclined screen, whether of a cylindrical or polygonal section, and consists in
the introduction into the interior of the screen of a metal or other cylinder or
drum extending either entirely or partly along the length of the screen. This
internal cylinder is carried by the spindle of the screen, and revolves with it;
it is closed at its upper end, and is of smaller diameter than the interior of the
screen, so as to leave an annular space of convenient width between it and the
screen to allow of the passage of the corn or other substances to be screened.
The object of this internal cylinger or drum is to prevent the corn or other
substances from being unduly agitated by the rotation of the screen, and to
keep it down upon the screening surface. It is adjustable on the spindle so
as to be capable of being shifted to any desired portion of the length of the
screen.
The second part of my Invention relates to certain peculiar constructions,
arrangements, and combinations of machinery or apparatus for manufacturing
cylindrical or polygonal rotatory screens of wire of any section, or other suitable
material, whereby considerable economy in their manufacture is obtained with
a better and more perfect article. According to this part of my Invention I
propose to form the shoulders on the ends of the longitudinal supports for the

page_text: wires by the aid of a machine provided with a traversing cutter or cutters
which act upon the ends of the wire, and reduce them to the proper size.so as
to form a shoulder thereon. The wire to be acted upon is held firmly in a
tubular holder or boss revolving in fixed bearings, and driven by pullies,
gearing, or otherwise, so as to impart a rotatory motion to the wire.. The
length of the tube depends upon the distance required between the shoulders,
and a cutter may be made to act upon each end simultaneously. The several
longitudinal wires or supports having been thus shouldered, are ready for the
construction of the framing or cage of the screen. The next operation is the
cutting in a spiral or helical direction a series of nicks or notches in
the several longitudinal wires or supporting bars for the reception of the wire
or other suitable material intended to form the screening surface of the screen;
the pitch or distance between these nicks or notches depends upon the size of
the meshes or openings of the screen. In cutting these nicks or notches,. the
frame or cage of the screen is, according to one modification, secured to a
spindle or shaft having a screw thread formed upon it working in a fixed nut,
the whole being supported in suitable bearings or standards. The pitch of
this screw must correspond with the pitch of the nicks or notches to be pro-
duced, consequently by changing the screw spindle for one of a larger or finer
pitch, screens of different sizes of meshes or openings can be made in the same
machine.
The nicks or notches are cut by means of a circular saw carried on a
spindle parallel to the cage; inside the cage there is a metal ring having
notches in its periphery, into which notches fit the longitudinal bars to be
nicked, the ring serving to hold the bars firmly and steadily whilst under the
action of the saw. An outer stationary ring, having a smooth internal surface,
bears upon the outer edges of the bars, and keeps them down upon the inner
ring, the bars being thus held steadily between the inner and outer rings; the
inner ring receives a rotatory motion from a spur pinion or pinions gearing
into teeth on the ring, the rotation of the inner ring carrying the cage or
frame round with it, so as to bring the several longitudinal supporting bars
successively under the action of the saw. This rotation of the cage or frame
and of its carrying spindle causes a longitudinal traverse to be also imparted
to the cage by reason of the screw thread of the spindle working in the fixed
nut, consequently the nicks or notches will be made in a spiral or helical
direction, and of the same pitch as the screw on the spindle. The inner ring
has no lateral motion, not being connected with the screw spindle.
According to another modification the longitudinal traverse may be imparted

page_text: to the saw in lieu of the cylinder, by making a screw thread on the saw
spindle, and causing it to work in a fixed nut; in this case the supporting
spindle or shaft of the screen will have no thread upon it. The wire or other
suitable material is now wound on to the cage or frame, being laid into the
nicks or notches already made in the longitudinal bars, and the screen is
completed by hammering down the edges of the nicks or notches over the coils
of wire or other suitable material, so as to hold each coil firmly in its place.
In order to support and steady the bars during the hammering of the nicks
or notches, a grooved metal block or anvil is held against their inner sides
by a spring or other equivalent contrivance, thus leaving both hands of the
workman at liberty.
And in order that my Invention may be fully understood, I shall now
proceed more particularly to describe the same, and for that purpose I shall
refer to the several Figures on the Sheets of Drawings hereunto annexed, the
same letters of reference indicating corresponding parts throughout all the
corresponding Figures.
Figure 1, on Sheet 1 of my Drawings, represents my improved screen in
longitudinal vertical section, shewing the internal cylinder A carried on the
screen shaft B, and placed inside the wire screen along a greater or less
portion of which it extends, as shewn in the Drawing. The upper end of the
cylinder A is closed, so that the corn must pass between the cylinder and the
screen.
Figure 2 represents a side elevation of a machine for cutting the shoulders
on the ends of the longitudinal supports or bars of cylindrical or polygonal wire
screens; Figure 3 is a corresponding plan of the same; Figure 4 is an eleva-
tion of the driving end of the machine; and Figure 5 is a similar view of the
opposite end of the machine.
A, A, are the supports or standards carrying the bed plate B, to which are
fitted bearings or plummer blocks C, C, carrying the driving shaft D. This
shaft is provided with fast and loose driving pullies E, E', and with two spur
pinions F, F, gearing into corresponding pinions G, G, fast on the screen
bar H to be operated upon. The screen bar is passed through the bosses of
the pinions G, and is held firmly therein by the thumbscrews I, I, so that on
a rotatory motion being imparted to the pinions G, the bar H will be carried
round with them. K, K, are two tool holders consisting of plates swinging
horizontally upon vertical stud pins or centres L, L, fixed to the bed plate B,
and M is a screw spindle working the tool holders for the purpose of bringing
them in or out of action, and for traversing the tools during the operation of

page_text: cutting the shoulder, a handle N at one or both ends of the spindle enabling
the attendant to traverse the cutters accordingly. 0, 0, are the cutting tools,
which are secured by set screws to the tool holders. When a screen bar is
placed in the machine, its two extremities project slightly beyond the bearings
or plummer blocks C, C, and pass through a hollow boss a, a, on the end
of each tool holder, the amount of screen bar projecting beyond the boss being
the part to be turned down or reduced to form a shoulder. The action of
the machine is precisely that of a lathe, the cutters being traversed to and fro
until the desired shoulder is formed, when the machine is stopped, the thumb-
screws loosened, and the shouldered bore removed to be replaced by a
fresh one.
Figure 6 represents a side elevation of a machine for slotting or nicking the
screen bars in a spiral direction for the reception of the wire, which is coiled
thereon, in the manner herein-after described; Figure 7 is a plan of the same;
Figure 8 is an elevation of the driving end of the machine; and Figure 9 is
a transverse section of the same taken through the line 1, 2, in Figure 6.
A, A, are the standards or supports, and B, B, the bed plates; C. C¹, are
the driving pullies running loose on a fixed stud bolted to the framing. To
one of these pullies is secured or cast in one piece therewith a spur pinion D,
gearing into the large spur wheel E, fast on the saw spindle F, which works
in the bearings G, G¹; the bearing G is adjustable by means of the adjusting
screw H, in order to regulate the depth of cut, the saw I being keyed on to the
adjustable end of the saw spindle. K is a small pinion fast on the saw spindle,
and driving the train of adjustable gearing L, L, which actuates the pinion
shaft M working in the bearings N, N. This shaft carries a spur pinion O,
the teeth of which are of such a pitch as to work between the several longi-
tudinal bars of the screen cage P (shewn on red lines on the Drawing). This
cage is mounted and fixed on the screw spindle Q, working in the bearings R, R',
the bearing R being screwed internally for the screwed part of the spindle to
work in, consequently, as the spindle and cage revolve they move longitudinally
at the same time. S is a spur wheel sliding along the spindle Q, and placed
inside the cage, the longitudinal bars of which rest in notches in the ends of the
teeth. Into this spur wheel gears the pinion O, and thus a rotatory motion is
transmitted to the cage. Round the exterior of the cage there is a stationary
ring T, which bears upon the longitudinal bars, and holds them steadily down
in the notches in the teeth of the internal spur wheel, each bar being thus
supported or held between two surfaces. The cage having been mounted upon
its spindle and placed in the machine, the saw is set up gradually so as to cut

page_text: successive slots or notches in the several bars of the cage as it revolves, and
since the cage travels longitudinally during its rotation, it follows that the
slots or notches are cut in à spiral or helical direction round the cage, the
pitch of each spiral, which is the guage of the mesh or openings in the screen,
coinciding with that of the thread on the screw spindle Q. U is an oil
reservoir, in which the lower part of the saw revolves to keep it constantly
lubricated, and facilitate the cutting operation.
The next operation is the coiling or winding of the wire or other suitable
material in the notches round the cage, and the final securing or rivetting
of the coils in their respective notches.
Figure 1, on Sheet Two of my Drawings, represents a side elevation of the
coiling and rivetting machine; and Figure 2 is a transverse section of the same.
The cage having been removed from the slotting machine is placed on the spindle
A (Figures 1 and 2, Sheet 2), supported by the bearings B, B, and the several
rings C, C, which support the bars of the cage having been adjusted in their
proper places, the operation of winding on or coiling of the wire D is com-
menced. The wire employed is contained on a drum or overhead reel E any
convenient break being applied thereto to impart the desired tension to the
wire as it is being wound round the cage, one end of the wire having been
secured to the end of the cage; the latter is rotated by hand or otherwise, and
the wire guided into the slots or notches in the longitudinal bars as the cage
revolves. In order finally to secure the coils in their places, each notch or
slot is hammered down over the wire deposited therein, and for this purpose
an anvil block F, grooved on its surface to receive the bars is introduced inside
the cage, and held firmly against the under side of the bars by the springs G,
thereby supporting the same whilst the workman hammers over or closes the
edges of the slots in order to secure the wire in its place. H is a hand-screw,
whereby the pressure of the anvil block against the under side of the bars may
be increased to any extent desired, or the block released for adjustment in a
fresh place.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe, in conclusion, that what I consider to be novel and
original, and therefore claim as the Invention secured to me by the herein-
before in part recited Letters Patent, is,-
First, the general construction, arrangement, and combination of machinery
or apparatus for the manufacture of cylindrical or polygonal screens, as herein-
before described.

page_text: Second, the combination with a rotatory screen of an internal cylinder or
drum of rather smaller diameter than the interior of the screen, for the
purpose herein-before described.
In witness whereof, I, the said William Nalder, have to this my
Specification set my hand and seal, this Thirteenth day of August,
One thousand eight hundred and sixty-three.
Witness,
ALFRED BELCHER,
Engineer,
East Challow,
Berkshire.
WILLIAM NALDER. (L.S.)