IMPROVEMENTS IN RAILWAY BRAKE APPARATUS
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by William Timbrill Clark and William
Henry Ashwell at the Office of the Commissioners of Patents on the 14th
February 1880.
WILLIAM TIMBRILL CLARK, of Crick, near Rugby, in the County of Warwick,
and WILLIAM HENRY ASHWELL, of Argyll House, Bedford, in the County of
Bedford, "IMPROVEMENTS IN RAILWAY BRAKE APPARATUS."
Our Invention has mainly for its object to construct an automatic railway brake
which may be worked either by compressed air, vacuum, or any compressed or
exhaust fluids.
The chief features in our Invention are that the brake apparatus can automatically
change itself from a compressed air to a vacuum brake, or when fitted up to take
the form of an hydraulic brake it will also automatically or by hand change itself*
into a compressed air, vacuum, or hydraulic brake.
For applying the brake blocks we use a cylinder and piston, the piston is fitted
with two cup leathers back to back, also two cup leathers fitted in the same
position on the piston rod. Round the centre of the piston is a groove; in
connection with this groove on one side of the piston is a small valve, so that when
the brake is worked by vacuum the vacuum is formed round the groove, thus
preventing any strain being put on the leather which is used for compressed air
or hydraulic.
As the leathers in pneumatic cylinders become hard and dry we propose to
lubricate them in two forms, one by making a hole right through the piston rod
and down through the piston from the top side in connection with the same, so that
lubrication may be forced through the piston rod and into the top part of the
cylinder between the two cup leathers, thus falling away on each side of the
cylinder and lubricating the leathers: there will also be a small hole with screwed
plug between the two leathers on the piston rod for the same purpose, also a small
valve in connection with the centre of the two leathers, so as to act when the brake
is worked by vacuum only. Secondly, by fixing a rifle in the end of the cylinder
down into the piston rod, or by fixing a pawl either to the cylinder cover or piston
working round a ratchet path on either of the same, thus causing the piston to
revolve a small portion each time the brake is applied, and at the same time
carrying lubrication from the bottom of the cylinder round with it. This cylinder
can be made longer with two pistons, as the one before described, thus pulling in
both directions,

page_text: The leathers are expanded by a metallic disc with pieces cut out round its edge
in the form of a V, the edges are then bent over, making the edges the same shape
as a cup leather; the object of this ring is that the leathers vary in quality, some
parts being hard, others being soft, so that each respective point of the disc will
keep its particular part of the leather tight to the cylinder.
When the brake is worked by vacuum there is a small auxiliary cylinder or body
of leather, india-rubber, or prepared cloth placed at any convenient position; this
is to compensate for the size of the piston rod, at the same time to keep the
brake off.
Along the carriage is carried a pipe or pipes, in connection with which is an
automatic reversable valve or valves; this valve or valves connect direct with the
receiver mounted on each carriage; back from the receiver is another pipe or pipes
connecting two sets of double valves. One set of these valves are for relieving the
pressure from the brake cylinder to the atmosphere when worked by compressed
air, and the other set for admitting the atinosphere when worked by vacuum.
These valves are connected to two small diaphragms; these diaphragms are in
connection with the train pipe, one acting with compressed air while the other is
actuated by vacuuin, but when either compressed air or vacuum is maintained in
only one end of the cylinder.
When the brake is off these two diaphragms are in connection with one chamber
only, but when separately each chamber is provided with two valves, the larger ones
being exposed to the train pipe with their seats in opposite directions. Connected to
these two valves are two smaller valves about half the area; these two valves are
open to the atmosphere when the larger ones are closed to the train pipe with their
seats in opposite directions. This same reversible motion might be attained by
placing three way cocks with separate valve chambers in connection with the
receiver.
This reversible motion may also be attained in various forms, the brake levers
can be worked by having a collapsible corrugated or plain insertion or other
prepared material with a piston placed in its centre, thus allowing the compressed
air to act on one side when the brake is in use by compressed air, and formning a
vacuum in the opposite side when worked by same.
When worked by vacuum in connection with this is two small auxiliary
cylinders or bodies of leather, or corrugated insertion, or any other prepared
material; these auxiliary cylinders are to connect a larger area, as formerly
described; instead of this a balance weight or spring night be substituted,
and these are in their respective turns (that is to say) when the brake is used by
compressed air or vacuum, these auxiliary cylinders are singly in connection with
the train pipo or pipes. Connected to the large piston in the centre is two
side rods, which are connected at the ends by a crosshead to connect the brake
levers.
Sliding on the piston pins are four small side rods with long slots connected to
two cross heads; these cross heads are fastened on one end of each of the small
auxiliary cylinders or collapsible bodies, these allowing the brake to actuate in its
respective position.
Another means of obtaining this reversible motion is by fixing a corrugated or
plain flexible diaphragm inside of an air tight chamber attached to the piston of
the diaphragin, and to the cover of the air tight chamber is a small plain or
corrugated diaphragm with its outer end open to the atmosphere; the object of
this is to alter the area of one side from the other of the larger diaphragm when
the brake is used by compressed air to keep the brake off, and to form a passage
for the piston rod. Inside of the larger collapsible diaphragm is another small
collapsible diaphragm, but exceeding in area the outside small one; the features of
this is to create a difference of area when the brake is worked by vacuum (that is
to say) when the brake is off the inside of this diaphragm is open to the atmosphere,
but when the brake is on a vacuum is created in the inside of this, exposing the
whole area of the piston to the atmosphero; this is attained by having two small

page_text: valves with their seats in opposite directions attached to a diaphragm, the
diaphragm being exposed to the vacuum in the train pipe or to the air tight
chamber; this inside collapsible diaphragm is not used when the brake is worked
by compressed air.
Another mode of obtaining the same is by having two collapsible diaphragms
attached to each other in the centre, covered only with a sheet-iron or cast-iron
casing merely to protect them, and to form a stationery cover at each end. In the
centre of these two diaphragms is attached a piston; this piston is connected to two
side levers, which are attached to the cross-head for coupling brake levers. Inside
of these collapsible diaphragms are two smaller diaphragms, one being connected to
the cover at one end and to the piston at the other, while the other is connected
only to the piston, having an independent cover of its own at the other end, and
being open from its inside to the atmosphere; these small diaphragms are to create.
a difference in the area when used by compressed air or vacuum so as to keep the
brake off.
Another ineans of obtaining the same is by having two plain or corrugated
collapsible diaphragms placed inside an air tight chamber with a small diaphragm,
as before described, forming a passage for the piston rods, and having an automatic
reversible valve in connection with the air tight chamber, and the centre of the
larger collapsible diaphragm being in direct communication with the train pipe or
pipes, so that when compressed air is used these diaphragms are collapsed to apply
the brake, but when vacuum is used the diaphragin is expanded, thus thrusting the
piston rod outwards to apply the brake.
At the end of the piston rod is attached a beam, suspended on a fulcrum in the
centre with a pin at either end, and projecting out at its side. In connection with
this is a gab of suitable construction. This gab is connected to a rod which is
coupled to the brake levers; there is also attached to this gab a small cylinder or
diaphragm, which is always in connection with the air tight chamber. The feature
of this cylinder or diaphragm is that when the brake is worked by vacuum it
collapses and places the gab in connection with one of the pins on the beam, and
when used with compressed air it expands and draws the gab from one pin to the
other, thus obtaining the same motion on the brake rods although a reverse motion
on the piston. This may be subject to various modifications, for instance, it night
be worked by a link supported in the centre, having the quadrant block to be lifted
either up or down by a small diaphragm or hand lever.
Another feature of our Invention is that the brake blocks are automatically
taken up as they wear; this is done in two forms.
When the brake is actuated by two small levers taking their fulcrums from a rod
passing along the inside of the wheels these two rods are attached to a rod at each
side of the wheels, this rod carrying a brake block at either end. The rod passing
inside the wheels is formed in two pieces, one end of each piece being screwed one
to a right hand thread, the other to a left hand thread; these are connected by
having a long nut with a right and left handed thread. This nut is formed at both
ends to form a ratchet pinion, and on the two front levers is supported a pawl,
this pawl being in connection with one end of the ratchet pinion at one end of the
nut, so that when the levers are forced back and the brake blocks opening from the
wheels the required space the pawl causes the ratchet to turn, thus causing the two
rods to coine closer together, the ratchet at the other end being furnished with a
pawl to keep the nut from turning back.again.
2nd. When the cylinder is fixed close under the bed of the carriage these two
levers are set vertically with the bottom ends, connected together by a rod in
two picces, the one taking the form of a sleeve whilst the other forms a rack,
the rack working into the sleeve. In the sleeve is a slot or slots, into which is a
pawl or pawls, so that when the brake is relieved its proper distance the alcove
slips over the rack and allows the pawl or pawls to drop into one or two of the
teeth, thus shortening the rods that couple the two levers, and drawing the blocks
closer to the wheels.

page_text: The hangers for brake blocks are forined of a ball and socket joint to allow for
oscillation of the wheels; these hangers are supplied with a ratchet rack to regulate
a distance from wheels.
Another feature of our Invention is to form a reversible coupling for the hose
between the carriages. This is attained by having a valve with two faces back to
back, and having a seating at each end of the valve box, so that when the brake is
worked by vacuum it will close on the seat next the carriage, but when worked by
compressed air it will close on the seat at the outside end of the coupling, but
when the two couplings are connected together the valve is held midway, so as to
give free passage for air or vacuum. This is attained either by a lever or levers
being connected to the valve chamber or to the valve.
The reversible valve in connection with the receiver and the train pipe is a
cylindrical valve sliding inside of another cylindrical chamber; this chamber has
two valve seats, one at either end for the cylindrical valve to rest against. Inside
of the cylindrical valve are two or more small valves; these valves have their seats
turned back to back, one of the small valve or valves answering when the brake is
used by compressed air, the other valve or valves when the brake is used for
vacuum. Connected to the cylindrical valve is a small diaphragm with its end
open to the atmosphere, so that when air is admitted into the train pipe it passes
into a chamber in the inside of the diaphragm, and thus draws the cylindrical
valve on its seat nearest the diaphragm, then the air is allowed to pass up the
centre of the cylindrical valve, then past the small valve or valves, and as soon as
the air pressure is destroyed in the train pipe the small valve or valves close on
their seats, thus retaining the pressure in the receiver. When the brake is used
for vacuu the atmospheric pressure acting on the diaphragm thrust the
cylindrical valves on the opposite seat, thus bringing the other small valve or
valves into action.
When the brake is worked by hand to reverse the vaives and passages of the
various fluids we combine all the passages in one cock.
When the brake is fitted to be worked by hydraulic as well as other fluid pressures
the receiver is fitted with a piston, so that the pressure will expand the pistons, the
piston being under control of a spring or lever so as to act as an accummulator.
The whole of the aforesaid arrangements can be worked singly as an automatic
compressed air, vacuum, or hydraulic brake.