IMPROVEMENTS IN RAILWAY BRAKES
Year: 1875

page_text: LETTERS PATENT to William Wrench Blades, of Nantwich, in the
County of Chester, for the Invention of "IMPROVEMENTS IN RAILWAY
BRAKES,"
Scaled the 7th September 1875, and dated the 2nd April 1875.
PROVISIONAL SPECIFICATION left by the said William Wrench
Blades at the Office of the Commissioners of Patents, with his
Petition, on the 2nd April 1875.
I, WILLIAM WRENCH BLADES, of Nantwich, in the County of Chester,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
IN RAILWAY BRAKES," to be as follows:-
-
My Invention relates to improvements in railway brakes of that class
in which the brake blocks are operated by the revolution of the carriage
wheels and axle, and the Invention consists in improved means of
effecting this object.
The main feature of my Invention is an endless chain or belt mado to
encircle loosely a drum keyed on the axle of a pair of wheels, said belt

page_text: or chain also passing over a pulley on a movable support, so that by
moving the said pulley away from the drum the belt will be tightened
and bite the drum, which in revolving with the axle will tend to carry
the chain or belt round with it. To this chain or belt, near the point
where when out of gear it passes over the supporting pulley, a chain or
other connection is attached, and is connected to a lever arm forming
part of the ordinary gear by which the brake blocks are operated. Thus
when the endless chain or belt is tightened up it will be carried partly
round with the drum until the chain or other connection is put in
tension and the brakes are applied, whereupon the resistance of the
latter will oppose the further movement of the chain or belt, and the
friction between it and the drum will determine the degree of pressure
with which the brake blocks are applied to the wheels. The chain or
belt may either be applied direct to the periphery of the drum, or a sort
of expanding friction clip may be interposed between the belt and the
drum, the said clip being formed by a number of curved plates in the
form of segments of a cylinder encircling the drum, and capable of being
_closed thereon to grip the same, or of being expanded to hold the chain
or belt free of the drum In this case the endless chain would be made
to gear with the outside of these plates, and the friction necessary to
apply the brakes would be obtained by the contact of the plates with
the periphery of the drum, which may be y grooved or otherwise shaped
to increase the friction if necessary, the curved plates being grooved or
shaped to correspond. These plates may be mounted on radial arms
loose on the axle, and may be pressed outwards away from the drum by
springs, when the chain or belt is slackened to take off the brakes.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Wrench Blades in the Great Seal Patent
Office on the 2nd October 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM 30
WRENCH BLADES, of Nantwich, in the County of Chester, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Second day of April, in the year
of our Lord One thousand cight hundred and seventy-five, in the 35

page_text: thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said William Wrench Blades,
Пer special licence that I, the said William Wrench Blades, my
executors, administrators, and assigns, or such others as I, the said
William Wrench Blades, 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, usc, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Islo
of Man, an Invention for "IMPROVEMENTS IN RAILWAY BRAKES," upon the
condition (amongst others) that I, the said William Wrench Blades,
my executors or administrators, by an instrument in writing under my,
or their, or one of their hands and scals, 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 with six calendar months next and immc-
diately after the date of the said Letters Patent
NOW KNOW YE, that I, the said William Wrench Blades, do
hereby declare the nature of my said Invention, and in what manner
the same is to be performed, to be particularly described and ascer-
tained in and by the following statement, reference being had to the
accompanying Sheet of Drawings, and to the letters and figures marked
thereon (that is to say).
--
My Invention relates to improvements in railway brakes of that class
in which the power required to apply the brake blocks to the wheels is
obtained from the momentum of the tram itself, and the Invention
consists in an improved arrangement of mechanism for operating the
brakes in this way.
The mechanism consists of an endless chain or belt made to encircle
loosely a drum keyed on one of the axles of a vehicle, said belt or chain
also passing over a pulley or any suitable support, made moveable so
that the belt may be tightened and caused to bite the drum, which in
revolving with the axle will tend to carry the chain or belt round with
it. To a convenient point in this endles chain or belt there is attached
a chain or other connection, which is suitably guided and connected to
the ordinary brake gear Thus when the endless chain or belt is tightened
up it will be carried partly round with the drum, in whichever direction

page_text: the latter may be revolving, until the said connection is put in tension
and the brakes are applied, whereupon the movement of the endless
chain or belt will be arrested, and the friction between it and the drum
will determine the degree of pressure with which the brake blocks are
applied to the wheels. The chain or belt might be applied direct to the
periphery of the drum, but I prefer to interpose a sort of expanding
friction clip between the belt and the drum, the said clip being formed
of a number of curved plates corresponding to and encircling the
periphery of the drum This clip is so constructed that when the belt
by which it is partly encircled is tightened some of the plates will be
caused to close upon and grip the drum, and when the belt is slackened
these plates will expand and keep free of the drum. In this case the
endless belt or chain would encircle and grip the plates, and the friction
necessary to apply the brakes would be obtained by the contact of the
plates with the periphery of the drum, which may be V grooved or
otherwise shaped to increase the friction if necessary, the curved plates
beng shaped to correspond These plates may be mounted on radial
arms carried by collars loose on the axle, and may be pressed outwards
away from the drum by springs, when the cham or belt is slackened to
take off the brakes.
Figure is a longitutmal scemon
carriage with my Invention applied, Figure 2 is a plan of the same.
Figure 3 is a side elevation, and Figure 4 a cross section of the friction
drum and clip drawn to a larger scale, Figure 5 is a detached view 2
showing one method of operating the Invention as a continuous
brake
The same letters of reference indicate the same parts in all the
Figures.
a is a cast-iron drum constructed in two halves, bolted together by
flanges for convenience in applying it on the wheel axle b, on which it
is keyed The drum is encircled by an expanding friction clip composed
of a number of segmental plates c of wood or metal, corresponding to
the periphery of drum a These segment plates c are mounted on radial
arms or spokes d fixed on collars e loose on axle bat either side of
drum a, and secured by wires d' threaded through holes in arms d.

page_text: These plates c may however be otherwise supported so as to be free to
be closed upon the drum, and revolve with it or to expand clear of the
drum and remain at rest independently of the movement of the said
drum. In the arrangement shown this is effected by fitting the plates
to slide on arms d and providing springs f, which tend to expand the
clip and hold the plates c clear of the drum is a belt of considerablo
`strength, and composed of leather or of an india-rubber coated fabric, or
a chain band might be used This belt encircles the expanding clip
loosely, and also passes over a pulley on the short arm of a lever i,
which is hung on a pivot at in a bracket fixed to the frame of the
vehicle. The other arm of this lever extends longitudinally beneath the
carriage, and has attached to its extremity a chain or other connection k,
by which thic lever 15 operated. Or the pulley h may be mounted on
any other moveable support, which may be operated in various other
ways, as hereafter mentioned. It will be readily scen that by moving
the pulley h away from the drum the belt g will be tightened sufficiently
to overcome the power of the springs f, and cause the plates c, or some
of them, to close upon the drum The clip and the belt will thus bc
caused to revolve with the drum, and the brakes will be applied to the
wheels through the tension of a chain or other connection 7 attached to
belt g, as shown, and connected to other chains m passing over suitable
guide pulleys and attached to the ordinary brake gear n.
The dotted lines in the Drawing show the position of the parts when
the brakes are appled, from which the action of the mechanism will be
readily understood.
I would remark that the gear m and n may be variously modified.
In the arrangement shown in Figures 1 and 2 the brakes are applied
by allowing the long arm of lever to fall by its own weight. When
however the brakes of all the carriages are operated simultaneously in
the manner of a continuous brake the weight of the levers might bo
insufficient to overcome the resistance of the chain by which they were
raised, and a second chain is provided to draw the levers down, as shown
in Figure 5, in which o is a continuous chain to raise the levers i, the said
chain passing over guide pulleys p and beneath a pulley" on the end of
s is another continuous chain passing beneath the guide
pulleys and over pulley », and serving to draw down the levers 1 to
bring the brakes to action, or the levers might be sufficiently weighted
instead of using two chains.
lever .

page_text: In lieu of this arrangement of chains (to which I lay no claim) for
operating the lever or other moveable support I might employ a suitable
modification of Fay's or Newall's continuous revolving shaft, or one of
the various pneumatic or hydraulic arrangements, or a suitable electro-
magnetic or other arrangement.
5
The belt might be applied direct to the drum a without the inter-
vention of a clip. In this case the belt might be kept from touching
the drum when not desired to apply the brakes by a counteracting lever
or spring arrangement of moveable guide mounted on a suitable part of
the vehicle, and the belt might itself be composed of a chain of curved 1
plates connected together.
Having described the nature of the Invention and the manner of
performing the same, declare that what I claim as the Invention to
bo protected by the herein-before in part recited Letters Patent is,-
1st. Connecting the brake block gear directly to an endless belt 1
encircling a drum fast on the wheel axle, means being provided for
tightening the belt and causing it to grip and revolve with the drum,
and also for preventing it from gripping when not required, all in the
manner and for the purpose herein described.
2rd. The employment, in combination with the drum on the wheel :
axle and the endless belt directly connected to the brake block gear as
described, of the friction clip interposed between the belt and the drum,
and constructed and operating after the manner and for the purpose set
forth.
In witness whereof, I, the said William Wrench Blades, have
hand and seal is First day of October.
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