IMPROVEMENTS IN WHEELS FOR TRAMWAY CARRIAGES
Year: 1877

page_text: LETTERS PATENT to Robert Hadfield, of Southampton Buildings, London, for
the Invention of "IMPROVEMENTS IN WHEELS FOR TRAMWAY CARRIAGES."
Ti
PROVISIONAL SPECIFICATION left by the said Robert Hadfield at the Office
of the Commissioners of Patents on the 20th January 1877.
ROBERT HADFIELD, of Southampton Buildings, London.
WHEELS FOR TRAMWAY CARRIAGES."
"IMPROVEMENTS IN
This Invention has for its object the manufacturing of an improved tramway car
wheel capable of resisting the sudden and extreme tension to which such wheels
are subjected owing to the frequent application of the break power consequent upon
the numerous and sudden stoppages which tramway carriages have to make in
order to take up and set down passengers, thus frequently pulling up within their
own length, and also of sustaining the shocks experienced at the various points and
crossings and of enduring the excessive wear and tear incidental to heavy gradients
and the other exigencies of railway traffic. I make such wheel either of ordinary
steel or of crucible cast steel, but preferably of the latter, which combines great
hardness with lightness, and form therein a suitable number of hollow cores which
materially contribute to the lightness of the wheel. It is also provided with a
suitable number of straight arms formed on the principle of a bridge girder so as
to resist great pressure and heavy weights, each of such arms being traversed
longitudinally at the back with a raised rib of suitable form and thickness, which
ribs are cast thereon at the same time as the wheel itself is cast. I also cast on the
back of the inner rim or circumference of the wheel in any convenient position a
suitable number of smaller ribs or projections which serve to strengthen and support
the same. Wheels constructed in this manner possess many great advantages; they
combine extreme lightness with immense wearing power and non-liability to
breakage at points and crossings, their elasticity permits of the expansion and
contraction of the metal, and when made of crucible steel they are practically
indestructible. They are also far more economical than the ordinary wheels.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Robert Hadfield in the Great Seal Patent Office on the 19th July
1877.
ROBERT HADFIELD, of Southampton Buildings, London. "IMPROVEMENTS IN
WHEELS FOR TRAMWAY CARRIAGES."
This Invention has for its object the manufacturing of an improved tramway car
wheel capable of resisting the sudden and extreme tension to which such wheels
are subjected owing to the frequent application of the break power consequent upon
the numerous and sudden stoppages which tramway carriages have to make in
order to take up and set down passengers, thus frequently pulling up within their
own length, and also of sustaining the shocks experienced at the various points and
crossings and of enduring the excessive wear and tear incidental to heavy gradients
and the other exigencies of tramway traffic. I make such wheel either of ordinary
steel or of crucible cast steel, but preferably of the latter, which combines great
strength with lightness, and I form therein a suitable number of hollow cores, which
cores materially contribute to the lightness of the wheel. It is also provided with
a suitable number of straight or rectilinear arms formed on the principle of a bridge
girder so as to resist the great pressure and heavy weights to which these wheels
are subjected, each of such arms being traversed longitudinally at the back with a
raised rib or girder of a suitable thickness, which ribs are cast thereon at the same
time as the wheel itself is cast. I also cast on the back of the inner circumference
of the wheel in any convenient position a suitable number of smaller or supple-
mentary ribs or projections which serve to strengthen and support the same.
And in order that my said Invention may be better understood and more readily
carried into effect I will now, with the aid of the accompanying Drawings, whereon
similar letters of reference indicate corresponding parts, proceed more particularly,
to describe and ascertain the same.
To manufacture such wheel I take a suitable wheel model or mould of the
necessary configuration to produce such a wheel as is shown at Figure 1 of the
accompanying Drawings. Such wheel is furnished with a nave having a suitable
hole formed therein to receive the axle, which may either run loose or be keyed and
fastened thereto, as preferred. Such Figure 1 shews a front view of one form of
my improved tramway wheel having six hollow cores a formed therein, and furnished
with six straight or rectilinear arms b, the centre of each of such arms being tra-
versed longitudinally in its rear with a raised rib cast thereon at the same time as
the wheel itself, as before described. These raised ribs are shown at c, Figure 2,
which represents a back view of one of my improved tramway car wheels, and at d
in the same Figure are shewn six smaller or supplementary ribs which are cast on
the back of the inner circumference of the wheel, as. before mentioned, for the pur-
pose of strengthening and supporting the same. One of the principal features of
my Invention is this particular form of arm which possesses considerable advantages
over the ordinary curved arms. hitherto in use, inasmuch as it is perfectly free from
all liability 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.
At Figure 3 I have shown a sectional view of one of such arms b. A lesser or
greater number of cores than six may be formed in the, wheel, and a corresponding
increase or diminution may also be made in the number of the arms and also of the
smaller or supplementary ribs cast on the inner rim of the wheel as may be preferred.
Wheels constructed in this manner will be found not only to possess great strength
elasticity, and lightness, but also to combine with these advantages, all the strength
and solidity of a solid disc wheel, at the same time that they are thoroughly homo-
geneous. They far excel those hitherto in use as their peculiar combination and
form render them free from the strains, jarring, and concussion existing in ordinary

page_text: wheels, and their wearing and lasting qualities are proportionately great, thus
rendering them far more economical.
Having thus particularly described and ascertained the nature of my said Inven-
tion and the manner of carrying the same into effect, I would have it understood
that what I claim and desire to secure by the herein-before in part recited Letters
Patent, is the casting either in crucible cast steel or in any other suitable steel a
tramway car wheel with a convenient number of hollow cores formed therein and
provided with a suitable number of rectilinear arms, each traversed longitudinally
at the back by a raised rib or girder, and furnished also with a convenient number
of smaller or supplementary ribs formed on the back of the inner circumference
thereof, substantially in the manner and for the purposes herein-before described
and illustrated.
In witness whereof, I, the said Robert Hadfield, have hereunto set my hand
and seal, this Nineteenth day of July, in the year of our Lord One thousand
eight hundred and seventy-seven.