IMPROVEMENTS IN THE MANU- FACTURE OF LEATHER. AND IN MACHINERY FOR THAT PURPOSE
Year: 1860

page_text: LETTERS PATENT to Robert Pitt, of Newark Iron Foundry, Bath, in the
County of Somerset, for the Invention of "IMPROVEMENTS IN THE MANU-
FACTURE OF LEATHER. AND IN MACHINERY FOR THAT PURPOSE."
the
PROVISIONAL SPECIFICATION left by the said Robert Pitt, at the
Office of the Commissioners of Patents, with his Petition, on
.6th March 1860.
I, ROBERT PITT, of Newark Iron Foundry, Bath, in the County of Somerset,
do hereby declare the nature of the Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF LEATHER, AND IN MACHINERY FOR THAT PURPOSE," to be as
follows:
This Invention has for its object improvements in the manufacture of
leather, and in machinery for that purpose. The operation in the manu-
facture of leather known as the striking the hide or skin, is now usually
performed by hand, but the application of machinery thereto has been pro-
posed and to some extent machinery has been employed. The machines
referred to consist of a roller on which a screw thread or worm is fixed; this
roller is caused to revolve at a considerable speed, and the hide or skin on
which the operation is to be performed is presented to the roller, and is
caused to pass slowly underneath it, the screw roller and the surface which
supports the hide or skin being at the samo time pressed towards each other
by springs, weights, or otherwise, two screw, threads, or worms, are employed
departing from a point at the centre of the length of the roller, and one of the
threads is right and the other left handed. The length of the screw roller is
about six feet, and this length is requisite in order that the machine may be

page_text: able to take full-sized hides or "buts." These machines when constructed as
heretofore employed or proposed would not work satisfactorily in practice,
principally because the pitch (or the distance between the threads) of the
screws has not been properly proportioned to the diameter of the roller. In
some cases it has been proposed to make the roller six inches only in diameter,
with a length of six feet or thereabout as before mentioned, and screw threads
or worms making one revolution in passing from the centre to the ends of the
roller. Machinery thus constructed would not work satisfactorily, because the
threads or worms are at so great an inclination to the work that they cause
the hide or skin to become stretched and thin to such an extent as considerably
to reduce its value.
Machines have also been constructed with rollers of eighteen inches in
diameter and with threads similarly arranged, but making more than, one
entire turn in passing from the centre to the ends of the roller. These
machines do not produce perfect work, because as more than two points of the
screw threads are at some periods over the work at one time, they will not all
bear upon it unless the hide or skin happens to be of uniform thickness, which
is rarely or never the case, so that in practice the whole of the pressure comes
on the two highest points, while the other points escape. Hence a machine
cannot work satisfactorily if the working portions of the threads or worms
make more than one complete revolution, that is to say practically, if the pitch
of the screw be much less than three feet, the necessary length of the roller
being six feet.
My Invention therefore consists in employing screws or worms not making
more than a complete revolution in the half length of the roller in combination
of a roller of eighteen inches in diameter at the least when this combination
is employed while but two points of the screw act on the skin at any one
time, the inclination of the thread is not so great as materially to stretch the
hide or skin.
My Invention also consists in casting the screw thread or worm of the material
known as white cast iron. When made of this material they wear much longer
than when made of gun metal or other material heretofore proposed.
:
My Invention also consists in attaching the screw thread or worm to the
roller, by making it slightly larger in interior diameter than the roller, and
when the two are placed together running in soft metal or other suitable
material in a liquid state, to fill the space between the two; by this means a
great saving in labor is effected.

page_text: SPECIFICATION in pursuance of the conditions of the. Letters Patent, filed
by the said Robert Pitt, in the Great Seal Patent Office on the
6th September 1860.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT PITT,
of Newark Iron Foundry, Bath, in the County of Somerset, send greeting.!
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Sixth day of March, in the year of our 'Lord
One thousand eight hundred and sixty, in the twenty-third year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said Robert Pitt, Her special licence that I, the said Robert Pitt,
my executors,. administrators, and assigns, or such others as I, the
said Robert Pitt, 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 THE MANUFACTURE OF LEATHER, AND IN MACHINERY FOR THAT
PURPOSE," upon the condition (amongst others) that I, the said Robert Pitt, my
executors or administrators, by an instrument in writing under my or their,
or one of their hands and seals, 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 calen
dar months next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Robert Pitt, do hereby declare
the nature of the 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 thereof, that is to say -
.: This Invention has for its object improvements in the manufacture of
leather, and in machinery for that purpose. The operation in the manufacture
of leather known as the striking the hide or skin is now usually performed
by band, but the application of machinery thereto has been proposed, and to
some extent machinery has been employed. The machines referred to consist
of a roller on which a screw thread or worm is fixed; this roller is caused to
revolve at a considerable speed, and the hide or skin on which the operation
is to be performed is presented to the roller, and is caused to pass slowly
underneath it the screw roller and the surface, which supports the hide or skin
being at the same time pressed towards each other by springs, weights or other-
wise. Two screw threads or worms are employed departing from a point at

page_text: the centre of the length of the roller, and one of the threads is right and
the other left handed.
The length of the screw roller is about six feet, and this length is requisite
in order that the machine may be able to take full-sized Lides or "butts."
These machines when constructed as heretofore employed or proposed would
not work satisfactorily in practice, principally because the pitch (or the distance
between the threads) of the screws have not been properly proportioned to
the diameter of the roller. In some cases it has been proposed to make the
roller six inches only in diameter, with a length of six feet or thereabout as
before mentioned, and with screw threads or worms making one revolution in
passing from the centre to the ends of the roller.
Machines thus constructed would not work satisfactorily, because the
threads or worms are at so great an inclination to the work, that they cause
the hide or skin to become stretched and thin to such an extent as considerably
to reduce its value.
Machines have also been constructed with rollers of 18 inches in diameter,
and with threads similarly arranged, but making more than one entire turn
in passing from the centre to the ends of the roller. These machines do not
produce perfect work, because as more than two points of the screw threads
are (at some periods) over the work at one time, they will not all bear upon
it unless the hide or skin happens to be of uniform thickness, which is rarely
or never the case, so that in practice the whole of the pressure comes on the
two bighest points, while the other points escape. Hence a machine cannot
work satisfactorily if the working portions of the threads or worms make
more than one complete revolution, that is to say, practically, if the pitch
of the screw be much less than three feet, the necessary length of the roller
being six feet.
My Invention therefore consists in employing screws or worms not making
more than a complete revolution in the half length of the roller in combination
with a roller of eighteen inches in diameter at the least. When this com-
bination is employed, while but two points of the screw act on the skin at
any one time, the inclination of the thread is not so great as materially to
stretch the hide or skin.
My Invention also consists in casting the screw thread or worm of the
material known as "white cast iron;" when made of this material they wear
much longer than when made of gun metal or other material heretofore proposed.
My Invention also consists in attaching the screw thread or worm to the
roller by making it slightly larger in interior diameter than the roller, and
when the two are placed together running in soft metal or other suitable

page_text: material in a liquid state to fill the space between the two; by this means a
great saving in labor is effected.
And in order that my said Invention may be most fully understood and readily.
carried into effect, I will proceed to describe the Drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a front view, and Figure 2 is an end view of a machine con-
structed according to my Invention. a, a, is the frame of the machine; bis
a roller for supporting the bide or skin to be operated on.
This roller may be
of wood, but I prefer it to be of galvanized iron plate; c is another metal
cylinder, it has a worm c¹ fixed on it by which the operation of striking is
performed; this roller. I make at the least eighteen inches in diameter,
measuring up to the working edges of the worm. In the Drawing this roller.
is shown of about twenty-four or twenty-five inches in diameter, and this size
I prefer. The worn c', a section of which is shown at Figure 3 is cast as
heretofore in one piece, but in white cast iron, in place of in gun metal, as is
now usual, which renders the worm more durable and cheaper. The worm is
cast so that its inside diameter is somewhat greater than that of the cylinder c;
it is then placed on the cylinder and temporarily held in its proper position
thereon by keys or otherwise, after which the space between the worm and
the cylinder is filled by pouring soft metal into it. The metal which I
prefer is pewter, and I run it in underneath the worm in lengths about a
foot at a time, the space into which it is to be poured being closed so as pro-
perly to retain the metal by fillets of wood or otherwise. The worm is also
screwed down to the roller, the soft metal being employed only to obtain a per-
fect fit; when fixed the spiral should bo ground straight and true with emery on a
lead plate. I find it advantageous to varnish the iron roller and to keep tho
spiral well greased to prevent staining the leather. The roller c is driven by
a strap passing over the drum d, and by preference at about 70 revolutions per
Its bearings are capable of sliding in the frame and are furnished
with adjusting screws e, e. The bearings of the roller bare also capable of
sliding in the frame and they rest on supporting bars f, f, which pass through
suitable guides, and have screw threads cut on their lower ends. They pass
through the screw nuts 9, 9, and into the sockets h, h, fixed on the strong
springs i, i. Thus these springs support the weight of the roller b, and press
it towards the roller ċ, with a pressure, which may be adjusted by turning the
screw nuts g, J. Blocks are inserted in the standards to prevent the rollers
ever coming into actual contact; j is an arm springing from one of the side
frames and carrying a stud or pink on it. A pinion is mounted, which
minute.

page_text: gears with the spur wheel m fixed on the axis of the roller b; the pinion 1 is
fixed to the ratchet wheel n, and this is driven by a double pawl o, centred to
the lever p, which also turns freely on the pin or stud k; this lever is slotted
at its other end, and by an excentric rod 7 actuated by the excentric r, on the
axis of the roller c, it receives motion, and the roller bis thus caused slowly
to revolve and to carry the hide or skin upon it gradually forward. The
speed of this motion can be varied by traversing the end of the excentric rod
along the slot in the lever p. The pinion is bouched with brass and its end
is pressed against the side standard by tightening up the nut on the pin or
stud k. The object of this arrangement is to produce a certain amount of
friction without which the hide would be drawn forward by the spiral and
cause the wheel and pinion to revolve rapidly; s is a treddle having rods t, t,
connecting it is as shewn with the axis of the roller b, so that by depressing the
treddle, the roller b can be drawn down out of contact with the roller c, as is
required to enable the workmen. to place the bides or skins in the machine;
t, t, are other treadles, which by depressing the further ends of the
treddle 8, press the roller b upwards and increase the pressure on the work.
Having thus described the nature of my Invention, and the manner of
performing the same, I would have it understood that what I claim is the
making the striking roller c cighteen inches in diameter at the least, and
combining therewith a worm c making but one revolution in passing in
either direction from the centre to the end thereof, so that on the one hand, as
before explained, the striking roller may not at any time (even when a full
sized bide or skin is being operated on,) rest on more than two points of the
hide or skin, and so that on the other hand the worm may not strike the
hide or skin at so great an inclination as to stretch it and render it thin.
.
I also claim the forming the worm of the striking roller of white cast
iron, and also the running in soft-metal or other material in a liquid
state underneath the worm in order to fit it to the roller as: herein-before
described.
In witness whereof, I, the said Robert Pitt, have hereunto set my
hand and seal; this First day of September, in the year of our Lord
One thousand eight hundred and sixty.