IMPROVEMENTS IN WHEELS FOR Tramway CARRIAGES
Year: 1875

page_text: LETTERS PATENT to Robert Hadfield, of Sheffield, in the County of
York, for the Invention of “IMPROVEMENTS IN WHEELS FOR Tramway
CARRIAGES."
Sealed the 26th November 1875, and dated the 4th June 1875.
PROVISIONAL SPECIFICATION left by the said Robert Hadfield at
the Office of the Commissioners of Patents, with his Petition, on
the 4th June 1875.
I, ROBERT HADFIELD, of Sheffield, in the County of York, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN WHEELS
FOR TRAMWAY CARRIAGES," to be as follows:-
This Invention has for its object improvements in wheels for tramway
carriages.
I proceed as follows:-I take a wheel model of the necessary form
and configuration to produce a wheel having six hollow cores formed
therein, such cores contribute materially to ensure the lightness of the
wheel. It is also provided with six curvilinear arms, the centre of each

page_text: of such arms being traversed longitudinally at its back with a raised rib
or corrugation, which is cast thereon at the same time as the wheel
itself is being cast. Such combined curvilinear and corrugated form of
arm constitutes one of the principal features of my improvements, and
possesses considerable advantages over the ordinary curved arms hitherto
in use, inasmuch as it is perfectly free from any susceptibility to
breakage, at the same time that it does not in any way interfere with
the necessary degree of elasticity requisite to allow of the expansion and
contraction of the metal.
A lesser number of cores than six may be formed in the wheel if
thought desirable, and a corresponding diminution may also be made in
the number of the arms.
Wheels constructed upon this principle will be found not only to
possess great strength, elasticity, and lightness, but to combine with
these advantages all the strength and solidity of a solid disc wheel at
the same time that they are economical and homogeneous and far excel
those in present use, as their peculiar combination and form render them
free from the strains, jarring, and concussion existing in ordinary
wheels, and their wearing and lasting qualities are proportionately
great.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Robert Hadfield in the Great Seal Patent Office
on the 29th November 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ROBERT
HADFIELD, of Sheffield, in the County of York, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fourth day of June, in the year of
our Lord One thousand cight hundred and seventy-five, in the thirty-
eighth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Robert Hadfield, Her special license,
that I, the said Robert Hadfield, my executors, administrators, and
assigns, or such others as I, the said Robert Hadfield, 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

page_text: After devoting much time, thought, and attention to overcoming
these difficulties, I have at length succeeded in devising and perfecting
a tramway wheel made preferably of crucible cast steel (or it may be of
ordinary steel), which combines great strength with lightness and is
capable of resisting any shock arising from brake power concussion
either at points, or crossings, or elsewhere; it also possesses great
elasticity united to immense wearing power, and is thus well adapted for
heavy gradients, at the same time that it ensures freedom from breakage
from any cause connected with tramway traffic.
Now in order to manufacture such wheel I take a wheel model of the 1
necessary form and configuration to produce a wheel, such as is shewn
at Figure 1 of the accompanying Drawings, and furnished with a nave
having a hole therein for the reception of the axle; such axle may either
run loose or it may if desired be keyed and fastened thereto.
'
Figure 1 of the accompanying Drawings is a front view of a tramway 1
wheel made in accordance with my improved method, having six hollow
cores respectively marked a formed therein, such cores contributing
materially to ensure the lightness of the wheel. It is also provided with
six curvilinear arms respectively marked b, the centre of each of such
arms being traversed longitudinally in its rear with a raised rib or 2
corrugation, which is cast thereon at the same time as the wheel itself
is being cast. These raised ribs or corrugations are shewn in the
accompanying Drawings at Figure 2, which is a back view of one of
such wheels and are respectively marked thereon with the letter d.
Such combined curvilinear and corrugated form of arm constitutes one 2
of the principal features of my improvements, and possesses considerable
advantages over the ordinary curved arms hitherto in use, inasmuch as I
have found that it is perfectly free from any susceptibility to breakage,
at the same time that it does not in any way interfere with the necessary
degree of elasticity requisite to allow of the expansion and contraction 3
of the metal.

page_text: Wheels constructed upon this principle will be found not only to
possess great strength, elasticity, and lightness, but combining with
these advantages all the strength and solidity of a solid disc wheel at the
same time that they are economical and homogenous and far excel those
in present use, as their peculiar combination and form render them free
from the strains, jarring, and concussion existing in ordinary wheels, and
their wearing and lasting qualities are proportionately great.
Having thus described the nature of my said improvements in wheels
for tramway carriages, and the manner of carrying the same into effect,
I would have. it understood that what I claim is the manufacture of
wheels for, tramway carriages, substantially in the form and by the
process herein-before described and illustrated.
In witness whereof, I, the said Robert Hadfield, have hereunto
set my hand and seal, this Twenty-ninth day of November, in
the year of our Lord One thousand eight hundred and seventy-
five.
ROBERT HADFIELD. (L.S.)