IMPROVE- MENTS IN HOISTING AND LOWERING MACHINES
Year: 1875

page_text: LETTERS PATENT to William Horatio Harfield, of the Mansion House
Buildings, in the City of London, for the Invention of "IMPROVE-
MENTS IN HOISTING AND LOWERING MACHINES."
Sealed the 4th May 1875, and dated the 11th March 1875.
PROVISIONAL SPECIFICATION left by the said William Horatio
Harfield at the Office of the Commissioners of Patents, with his
Petition, on the 11th March 1875.
I, WILLIAM HORATIO HARFIELD, of the Mansion House Buildings,
in the City of London, do hereby declare the nature of the said Inven-
tion for "IMPROVEMENTS IN HOISTING AND LOWERING MACHINES," to be as
follows:-
G
In hoisting and lowering machines subject to sudden or excessive
strains, and in which toothed gearing is used, it has been found difficult
to combine lightness with the requisite strength if made in cast iron.
In some cases wrought iron has been used in consequence of the
greater strength and reliability of that metal,

page_text: The first part of my Invention consists of an improved method of
making such wheels, and is as follows:-A round plate of iron is turned
on its edge slightly larger than the internal diameter of a tire or rim of
considerable breadth which is heated, the expansion allowing it to be
passed over the plate which is to be placed in the centre of the rim ;
on cooling the tire contracts on the plate with great force, the edge of
tire can then have the teeth shaped out and a central boss can be formed
on the plate by rivetting additional plates to it.
In some cases instead of shrinking the tire on the circular or web
plate as above I turn a recess in the interior of the tire in width equal
to the thickness of the web plate, the interior diameter or recess being
slightly less than the exterior diameter of web plate; the tire is
expanded by heat and passed over web plate which is thus held laterally
in its place by the recess. The contraction of the tire will generally fix
the web plato perfectly tight, but in some cases it may be advisable to
insert a few pins through the tire into the edge of web plate.
In some cases I fix into the tiro brackets at intervals round its
interior and place a thin plate on each side, rivets passing through the
two thin plates, and the brackets unite the web plates with the tire, and
the space between the two web plates can be filled up at the centre so
as to form a boss.
The second part of my Invention is an improved method of forming
the discs frequently used in hoisting and other machines forming the
combination known as the compound disc brake and connection. It
has been found that after the double series of discs forming the brako
have been pressed together with great force, bringing the discs in close
surface contact, there is a tendency for the double series of discs to
remain in the same position of close surface contact when the initial
force applied in pressing them together is removed. To obviate this
defect I corrugate, dish, or bend some of the discs instead of making
them flat as hitherto, the effect of this is to cause elasticity in such discs,
thus making them move slightly from those immediately next them;
this slight movement however being sufficient to ensure the immediate
release of the discs from their position of close surface contact one with
the other on the removal of the force which kept them pressed together.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Horatio Harfield in the Great Seal Patent
Office on the 11th September 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HORATIO HARFIELD, of the Mansion House Buildings, in the City of
London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of March, in the year of
our Lord One thousand eight hundred and seventy-five, in the thirty-
cighth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said William Horatio Harfield, Her special
license, that I, the said William Horatio Harfield, my exccutors,
administrators, and assigns, or such others as I, the said William
Horatio Harfield, my executors, administrators, and 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 HOISTING AND LOWERING MACHINES," upon
the condition (amongst others) that I, the said William Horatio Harfield,
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 calendar months next and
immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said William Horatio Harfield, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in
and by the following statement thereof, that is to say :-
In hoisting and lowering machines subject to sudden or excessive
strains, and in which toothed gearing is used, it has been found difficult
to combine lightness with the requisite strength if made in cast iron.
In some cases wrought iron has been used in consequence of the
greater strength and reliability of that metal.

page_text: The first part of my Invention consists of an improved method of
making such wheels, and is as follows:-A round plate of iron is turned
on its edge slightly larger than the internal diameter of a tire or rim of
considerable breadth which is heated, the expansion allowing it to be
passed over the plate which is to be placed in the centre of the rim; on
cooling the tire contracts on the plate with great force, the edge of tire
can then have the teeth shaped out, and a central boss can be formed on
the plate by rivetting additional plates to it.
In some cases instead of shrinking the tire on the circular or web
plate as above, I turn a recess in the interior of the tire, in width equal 1
to the thickness of the web plate, the interior diameter of recess being
slightly less than the exterior diameter of web plate; the tire is
expanded by heat and passed over web plate which is thus held laterally
in its place by the recess. The contraction of the tire will generally fix
the web plate perfectly tight, but in some cases it may be advisable to 1
insert a few pins through the tire into the edge of web plate.
In some cases I fix into the tire brackets at intervals round its interior,
and place a thin circular web plate on each side of the brackets, rivets
passing through the two thin web plates, and the brackets unite the web
plates with the tire, and the space between the two web plates can be 2
filled up at the centre so as to form a boss.
I claim as respects this part of my Invention the construction of the
toothed gearing wheels of hoisting and lowering machines, substantially
in the ways herein-before described.
The second part of my Invention is an improved method of forming 2
the discs frequently used in hoisting and other machines forming the
combination known as the compound disc brake and connection. It
has been found that after the double series of discs forming the brake
have been pressed together with great force, bringing the discs in close
surface contact, there is a tendency for the double series of discs to 3
remain in the same position of close surface contact when the initial
force applied in pressing them together is removed. To obviate this
defect I corrugate, dish, or bend some of the discs instead of making
them flat as hitherto, the effect of this is to cause elasticity in such
dises, thus making them move slightly from those immediately next
them, this slight movement however being sufficient to ensure the
immediate release of the discs from their position of close surface contact

page_text: one with the other on the removal of the force which kept them pressed
together.
I claim making the discs of the disc brakes of hoisting and lowering
machines either corrugated, dished or bent, as and for the purpose
above described.
In witness whereof, I, the said William Horatio Harfield, have
hereunto set my hand and seal, this Ninth day of September, in
the year of our Lord One thousand eight hundred and seventy-
five.