AN IMPROVEMENT IN BRAKES
Year: 1884

page_text: I JOHN IMRAY of N° 28 Southampton Buildings Chancery Lane in the County
of Middlesex, Consulting Engineer and Patent Agent do hereby declare the nature
of the said invention for "AN IMPROVEMENT IN BRAKES," to be as follows:-
According to this invention, an elastic band is wound helically in several
convolutions round the periphery of a drum or cylindrical boss fixed on a revolving
shaft or axle to which it is desired to apply a brake. The helix is made of an
internal diameter a little greater than the external diameter of the cylinder to which
it is applied, so that when it is loose it exerts no friction; but on subjecting the
ends of the band to tension, or one of these ends while the other is fixed, the
convolutions are caused to grasp the cylindrical surface causing friction which
retards or stops its revolution.
In applying this form of brake to wheeled vehicles, such as those of a railway
train, it is necessary to provide means of pulling either end of the helical strap
according as the vehicle may be running in the one direction or the other, but
generally it is preferable to provide in each case duplicate brakes, one arranged for
each direction of motion. The several helical bands throughout the train may be
tightened by pulling a continuous chain or cord from the engine or from a guard's
van. It is better, however, to employ the tension of such continuous chain or cord
to hold the brakes off in opposition to weights or springs which, when the continuous
chain or cord is slackened or when it is broken by separation of the train, tighten
the helical bands and so put on the brakes automatically. In some cases, it is of
advantage to connect the brakes to the traction or buffer springs, so that when the
engine pulls the train, the brakes are held off, but when the engine is retarded the
brakes are put on. For this purpose the movement of the traction or buffer spring
is multiplied by arranging it to act on the short arm of a lever, the long arm of
which is connected to the hélical bands and to the weights or springs that tighten
them. Thus a small movement of the traction or buffer spring is magnified by the
leverage so that in one condition of the spring the brakes are kept off, and in
another condition of the spring they are automatically put on by the weights or
springs being allowed to tighten the helical bands.
J
ABEL & IMRAY,'
Agents for the Applicant,
28, Southampton Buildings,
London, W.C.

page_text: I, JOHN IMRAY, of No 28 Southampton Buildings, Chancery Lane in the County
of Middlesex, Consulting Engineer and Patent Agent do hereby declare the nature
of my invention for "AN IMPROVEMENT IN BRAKES," and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement :-
•
According to this invention, an elastic band is wound helically in several
convolutions round the periphery of a drum or cylindrical boss fixed on a revolving
shaft or axle to which it is desired to apply a brake. The helix is made of an
internal diameter a little greater than the external diameter of the cylinder
to which it is applied, so that when it is loose it exerts no friction; but on
subjecting the ends of the band to tension, or one of these ends while the other is
fixed, the convolutions are caused to grasp the cylindrical surface causing friction'
which retards or stops its revolution.
'
In applying this form of brake to wheeled vehicles, such as those of a railway
train, it is necessary to provide means of pulling either end of the helical strap
according as the vehicle may be running in the one direction or the other, but
generally it is preferable to provide in each case duplicate brakes, one arranged for
each direction of motion. The several helical bands throughout the train may be
tightened by pulling a continuous chain or cord from the engine or from a guard's
van. It is better, however, to employ the tension of such continuous chain or cord
to hold the brakes off in opposition to weights or springs which, when the
continuous chain or cord is slackened or when it is broken by separation of the
train, tighten the helical bands and so put on the brakes automatically. In some
cases, it is of advantage to connect the brakes to the traction or buffer springs, so
that when the engine pulls the train, the brakes are held off, but when the engine
is retarded the brakes are put on. For this purpose the movement of the traction
or buffer spring is multiplied by arranging it to act on the short arm of a lever,
the long arm of which is connected to the helical bands and to the weights or
springs that tighten them. Thus a small movement of the traction or buffer
spring is magnified by the leverage so that in one condition of the spring the
brakes are kept off, and in another condition of the spring they are automatically
put on by the weights or springs being allowed to tighten the helical bands.
DESCRIPTION OF THE DRAWINGS.
Fig. 1 of the accompanying drawings shews the construction of the above
described invention.

page_text: decrease from the one end to the other.
elliptic, triangular, or of T shape &c &c.
Its section may be trapezoidal, circular,
The drum may either be cylindrical or slightly conical.
The coiled band instead of forming a cylinder, may also be slightly conical.
It is to be observed with reference to the action of this brake that;
1, The power of the brake increases very rapidly with the number of convolutions
of the coil.
2, The fixed point may be placed either behind or in front, relatively to the
direction of rotation of the drum, but the first named arrangement is the most
advantageous; in this case it will be possible, by applying a moderate tension to the
free end, to produce a greatly increased strain on the fixed end in proportion to the
number of convolutions of the coil. .
It results from the above that if the revolving axis carrying the drum has a
considerable momentum in consequence of its great weight or of its great speed, or
by both combined, then a moderate pull exerted on the free end of a coil having a
sufficient number of convolutions will produce in addition to the retarding pressure
upon the drum a very great tension on the fixed end situated behind the direction
of rotation, and if this end be fixed to some part of a machine requiring to transmit
a very great force with a slight motion, the coiled band may serve as the temporary
connection between the revolving cylinder and certain other mechanism to be
actuated thereby, and may thus act as a transmitter of power.
Fig. 20 shews the elastic coil H applied to a shaft A having a fly wheel M
revolving in the direction f; xx is the axis of rotation; if a force t. be applied to
the free end a connection will be formed between the coil H and the shaft A, and
a tension Qwill at the same time be developed at the other end of the coil.
If the tension Q be applied to the shaft D for instance by means of the lever A B
such tension can be transmitted to a resistance P through a lever BC; it will be
seen that if the movement be very small the coil H H will not be altered; on the
other hand the elastic nature of the coil will cause this transmitted strain to cease
immediately the pull upon the free end is relaxed, that is, as quickly as the strain
was applied.
1
This tension on the end of the coil situated behind the direction of rotation maý
be utilised in a great variety of ways, and in particular for applying brake blocks to
revolving bodies, thus transmitting the action of the coil as a brake to other shafts
or machines situated at a distance.
This system of brakes is consequently generally applicable to all revolving shafts
to all wheeled vehicles either on railways, tramways or common roads.
The coil may be applied either to the bosses of wheels or to drums fixed to the
wheels if they are loose, or fixed to the axles if the wheels are fixed, as shown at
Figs. 10, 11 and 12.
The drum or the boss can be covered with material that produces considerable
friction and that can be renewed when worn away.
The coil may also be arranged as follows:
The coils may overlap each other partially as at Fig. 13, or entirely as at Figs. 14
to 19; these figures shew an arrangement for passing the free end between the two
fixed ends.
With regard to the fixing of the coil in place, this may be rendered difficult by
the existence of other objects fixed on the revolving shaft, such as for instance
when the coil is to be placed on an axle having a wheel fixed on either end. ‘In
such cases the coil may be made of one continuous length in the first instance and
be then cut up into separate segments whereby it can be applied to the drum on
the axle, and the separate lengths be then joined together by rivets or bolts with
countersunk heads or hinges, so as to form a continuous length again' as shewn at
Figs 21 to 24.
As the fixed end of the coil must be situated behind the direction of rotation of
the drum, it follows that if the latter is required to operate when revolving in either
direction; it must be provided with two coils, arranged with their fixed ends in

page_text: opposite directions, the one or the other being put in action according as the drum
revolves in one direction or the other. If, each coil is to operate in one direction
only, the strap should be made of decreasing section from the fixed end to the free
end, as the strain increases rapidly in the contrary direction. As furthermore it
may be necessary to guard against undue increase of friction in the coils approaching 5
the fixed end, and in particular at the point where the band passes tangentially
from the drum to the fixed point or resistance, it is advisable to make the band of
increasing width as well as thickness towards that point, so as to offer an increasing
frictional surface to the drum.
As the coil is required to operate instantaneously in applying and relaxing the
strain, the thickness and configuration of the section thereof should be so
proportioned as to afford a certain elasticity in relation to the force exerted thereby
at the various points of its length.
By so constructing the coil that each end may, at will, be made to serve as the
fixed end or as the loose end, it may be made to operate in whatever direction
the drum may be turned, in which case the band would be of uniform section
throughout.
Thus at Figs. 25 and 26 the released coil is shewn in strong black lines at R R
while the thin lines at R R shew the coil tightened on the drum T.
For this purpose a flexible cord passes round a pulley P and has its two ends
attached respectively to the two ends of the coil.
Two other flexible cords G¹ F¹ and G¹ F connect the ends of the coil respectively
to a fixed point.
If the lever K. O K¹ be actuated so as by means of the pulley P to tighten the
corresponding cord, the coil is caused to tighten on the drum T, and if the direction
of rotation is that of the arrow f, the cord G¹ F1 is tightened according to F1 G
while the cord G F loosens and takes the position F G, the extremity G¹ having
moved to G.
If on the other hand the pulley P descends again to P' the reverse effect will be
produced and the coil will be at once released.
If the direction of rotation is the opposite one, namely that of f1, the points G¹
will occupy relatively to the axis Y Y, positions symmetrical to those of the
preceding case when the cord bc is tightened by means of the pulley P.
It is evident that the motion of the lever K K₁ could be produced either through
the medium of a chain, or by the release of a counterweight, or any other power,
such as steam, electricity, compressed air or vacuum, may be used to effect the
movement of the pulley P.
Figs 27 and 28 shew another arrangement for employing a single coil when the
drum T rotates in both directions. For this purpose two rollers G G¹ rotate upon
one and the same axis a a which is moveable within certain limits by means of a
lever K K. These rollers are each composed of two coucentric cylinders of unequal
diameter, of which those of larger diameter are in contact with the drum T and are
rotated thereby, while a cord attached to the ends A B of the coil is wound up on
the cylinders of small diameter. These cords are in the positions of A¹ A¹ and
B B¹ during the release of the coil.
Each end of the coil is in addition attached by another cord to a fixed point.
These cords are at A F¹ and B F when the coil is released.
If at Fig. 27 the rollers with their axes are allowed to descend from G¹ to G or
from a¹ to a the fixed cord A' F' will tighten according to A F', the loose
cord B B will be coiled up as at B V q and the coil will tighten on the drum. It
will be observed that the cord B₁ F is slacked as at F B.
If the reverse rotation be effected the same operations will take place
symmetrically with reference to the axis Z Z.
It is to be observed that by friction the roller G1 has likewise been made to
revolve on the axis a a and has consequently drawn the cord A¹ A', but this is of
no importance because this tension acts upon the fixed end, which is being
subjected to a very much greater strain in the contrary direction by the coil,

page_text: The rollers miglit however be on separate axes, each of which might then be
operated separately.
The motion of the axis a and of the rollers may be effected as set forth in the
preceding example.
Another mode of applying the coil by means of two rollers on separate axes,
applicable to car wheels and shafting will be hereinafter described.
When the elastic coil is applied to the bosses of wheels running on common
roads, a single coil for each wheel will suffice as these wheels may generally be
taken to run only in one direction.
The fixed end being attached to the axle or the body of the vehicle the free end
can be actuated either by chains or rods, and as the force to be applied will be
comparatively small, the brake may be applied by the driver or even by a postillion..
The chains or rods may also be led along the pole of the vehicle and passing over a
pulley at the end thereof, may have their ends attached to the horses harness so
that the brakes may be applied by the backward pull of the horses on stopping or
going down hill, whereby they will be relieved of the drag put upon them by the
vehicle itself.
In the case of railway or tramway vehicles, which travel in both directions, one
of the before described arrangements in which a single coil is made to operate in
both directions must be employed.
To save the axles from strain, the drums may be fixed against the wheels; the
fixed ends of the coils may be attached to the carriage frame while the free ends
are all attached to a bar, chain or other device extending along the train.
In using two coils for each axle there would be one reaction less for each fixed
point, the coils would be of smaller dimensions and could be more conveniently
placed. By attaching the fixed ends in a vertical direction the strain of the axle
boxes against the horn plates and of the journals in the axle boxes would be
avoided, but on the other hand the springs would be subjected to compression
during the application of the brakes.
An example will therefore be described which will subject both the journals and
the springs to the least strain, as also an arrangement for applying the invention as
an automatic continuous brake.
The examples are shewn as applied to existing constructions of rolling stock.
In Figs. 29, 30 and 31 the springs are supposed to be of ordinary construction
acting both for buffer and draw bar and the transmission of the brake power froni
one end of the train to the other is effected by bars A-B under each carriage with
a V coupling (similar to that of Clarke's chain brake) between the carriages.
The carriages travel in the direction f, and if the rollers G be put in contact with
the wheel tyres, the chains a will assume the position a¹, the coils will be applied
to the drums while the chains b, will be stretched into the position b¹. If the
rollers G be applied to the wheel tyres with sufficient force, the tension on the
chains a will be sufficient to apply the brakes effectively.
For applying the rollers to the wheels, the bar A B is pulled in the direction of
the arrow f, the spring R will be strained, and the head of the lever T will be
pushed from left to right, and at the same time the rods d d will move the two
rollers G away from the wheels. These rollers being free will have their chains a
pulled off them by the elasticity of the coiled bands, which tend to assume their
slacked position.
The chains b² will be strained into the position b, and the rollers G being free to
assume their vertical position, move away from the wheels. This movement of the
rollers may also be effected as follows. The motion of the bar A B from right to
left acts upon the stud D of the suspension D D¹ and the latter acting upon the
rods g g brings the rollers G into the position away from wheels. If now the
rod A B be released the spring R being free to act, contracts and causes the rods of
5 the rollers to perform the reverse motion to that before described, that is to say,
establishes the condition shewn at Fig. 29. It will be seen that if the carriage
were travelling in 'the'contrary direction, it would be sufficient to draw the bar A B
شده

page_text: .
in the contrary direction to cause the various above described operations to bę
reproduced symmetrically with reference to a vertical axis,
The brakes may be actuated from the tender or engine by means either of
a screw, toothed gearing or by steam power.
A strain of less than 220 lbs. for each carriage will suffice to produce the requisite
pressure of the rollers G on the wheels so as to apply the brakes; consequently from
4400 to 6600 lbs. strain at the engine or brake van will suffice to draw off the
brakes and strain the springs R, which afterwards apply the brakes when the
strain is taken off the continuous rods. It will be readily seen that this system is
automatic, as should the continuous connection be broken all the springs R will be
free to effect the application of the brakes on the detached carriages. It will be
evident that one or more groups of these carriages may be combined in a train each
group having one carriage with hand brake gear, so as to put a certain number of
brakes under the control of one guard.and thus obviate the necessity for too great
a number of these.
When it is desired to back the carriages, the continuous rod should be drawn so
as to move the rollers away from the wheels.
•
When the carriages are at rest the brakes are applied, if it be desired to actuate
the brakes of a separated carriage by hand, the lever k k connected to the bar A B,
is actuated.
Figs. 32 and 33 shew another arrangement in which the rollers are moved to and
from the wheels by the draw bars. Each spring is supposed to be common to the
buffers and draw bar. As, for the purpose of putting the brake out of action, a
motion of the draw bar of about ths inch is required, the main plate F of the spring
is supposed to be of such strength as to require a strain of about 110 lbs. to move
it the inch. Under these conditions the pulley P¹ will turn under the action of
the chain H and will raise the counter weight U so that the rollers are moved from
the wheels. If on the contrary the traction ceases, the counterweight U falls and
the rollers are applied to the wheels so as to bring the brakes in action. In
backing, the buffer rods act upon levers L L which by means of the fork O' L' cause
the pulley to turn so as to raise the counterweight U and put the brakes out of
action.
For the tail carriage the pulley situated at the back end should be disconnected,
as there is no effort of traction on the last spring of the train.
The lever QL may serve to put the brakes of each carriage out of gear for
shunting in the stations; this lever also serves as a hand brake.
With the above arrangement the couplings between the carriages cannot be
tightened in the case of goods trains this will not matter much, as the couplings
are generally loose.
Figs. 34 and 35 shew the arrangement for coupling for trains with continuous
draw bar, the springs serving both for draw bar and for buffers.
The draw bar is connected to two springs R R¹ and two sway beams T T¹ by
means of strong plates A. B. The springs R R¹ are identical and are placed with
an initial strain of about 4,400 lbs. and so that with a strain of about 220 lbs. they
will move about from 2 to 3 inches..
If there is no pull upon the draw bar, the two springs R R¹ are in equilibrio, but
if for instance the bar K be drawn in the direction of the arrow with a force of
about 110 lbs. the spring R will assume a flexure corresponding to the effort owing
to the action of the opposed spring R¹ which is of the same strength and initial
strain. With a strain of 8800 lbs. R¹ will assume its original flexure and will
cease to act upon the draw bar in the direction of motion; but this condition does
not require to be considered under the circumstances where it is merely a question..
of bringing the rollers G in or out of contact with the wheels.
As a very small movement of the draw bar will give the necessary movement to
the rollers for bringing them in action one may always be certain of having the
necessary motion of the draw bar for taking off the brakes even with detached
Carriages,
27
-

page_text: The drawing shews that the apparatus will operate for both directions of motion,
and that the buffer and draw bar springs produce themselves the application of the
brakes. The apparatus is consequently automatic in the case of the couplings
breaking.
The application of means is necessary for keeping the buffers always in contact
without the aid of the tension of the couplings at the time of making up the train.
For this purpose the sway beam T is always moved with the draw bar; thus
if at the time of coupling, the buffers are put in contact they will remain so whether
in parallel position or at an angle, as shewn in dotted lines.
The drawing shews an arrangement permitting the application of a brake by
hand; for this purpose the lever HP acts upon two rods LG K M of which the
ends are forked in order not to interfere with the action of the draw bar.
In backing, the movement is transmitted by means of the buffers and sway
beams in actuating one of the two springs and the draw bar is actuated so as to
release the brakes.
The coupling of one carriage with another can be effected by linch pins or by
draw hooks and coupling links, provided if it be seen that the buffers are merely
put in contact.
The parts of the last described arrangement are very simple, and the system
evidently permits of the use of groups of these carriages between the ordinary
carriages of a train. In this last arrangement the brakes are applied when neither
the draw bars nor the buffers are acted upon by the engine; in the contrary case
the brakes are put out of action.
If it is feared that the action on the brakes be not sufficiently precise under
these conditions, in particular when going down hill, another arrangement may be
employed. In going down hill all the brakes would be applied simultaneously;
also in allowing the train to slacken speed gradually it may be stopped quicker
than desired. It would therefore be desirable in both cases to use steam inter-
mittently in order to impart the necessary motion to the train. On inclines this
steam would, it is true, serve to lubricate the piston and slides.
In order to avoid this intermittent admission of steam, the arrangement shewn
at Figs. 36 and 37 may be employed. These figures shew the tender and first
carriage of a train; the spring R of the tender serves both for buffer and draw, bar
as is usual,
A lever A B having its fulcrum at A can be brought into the position A B¹ by
means of a rod B₁ D connected to actuating gear consisting either of toothed gear,
screw, or a single acting steam cylinder. The lever A B can actuate the draw
bar K; in doing this, the latter actuates the continuous coupling bar and at the
same time the buffers P¹ which will actuate the buffers P; these latter will react
upon the draw springs R; the continuous coupling can therefore assume, at will
a progressive motion relatively to the framing of the carriages and take off the
brakes.
It is evident that by this arrangement the driver can, even when the train is
stationary take off the brakes by putting tension on the couplings of the tender or
engine. He can therefore before starting, whether for forward or for backward
motion actuate the couplings for this purpose.
.
On releasing the strain on the couplings the brakes will be applied by the action
of the springs without admitting steam. It has before been shewn that the force
required for putting the initial strain on these springs does not exceed the limits
that can be attained with the ordinary brake gear.
Small springs are shewn connected to the draw bar acting upon the sway
beams T T Figs. 34 and 35, in order to prevent the latter and the corresponding
buffers from assuming the speed acquired in passing round curves. These springs
may be replaced by helical springs arranged round the buffer rods.
Figs 38 and 39 shew an arrangement in which the spring coil is made to
transmit the momentum of a revolving body to another operating mechanism, sụch
as ordinary brake block gear.

page_text: 1
A and B are two rollers having each a barrel T on which is wound the coil, the
flanges g of the rollers being removable for this purpose The free end of the coil'H
may be wound upon the other barrel, while the 'fixed end actuates the beam of the
brake blocks D¹. The arrangement of the roller B on the opposite side of the axle
is identical with that of A. The draw bar will slacken the coils and take off the
. brakes acting upon the rods F F through the gear E L M and E, as in the
preceding arrangements. If on the other hand the draw bar assumes the neutral
position, the rollers will come in contact with the axle C C.
.
If the direction of rotation of the wheels be f; the drawing shews that the coil H
will be tightened in the sense of the motion of the roller A, while H will tend to
slacken corresponding to the movement of B; consequently the coil H will tighten
upon A, the free end N P will be wound up on the barrel of the roller B, the
movement of which is free, while the fixed end Q of the coil will act upon the brake
block D' through the gear Q R.
If the carriage moves in the contrary direction the roller B will act upon the
brake block D through the coil H'.
It will be seen that in this combination the two cords N P and Q R tend to
apply the roller A to the axle C C with the greater force, the greater the pressure
of the brake block D¹ is upon the wheel; that is to say, the action of the apparatus
will increase in force in proportion as greater brake power is required.
Having now particularly described and ascertained the nature of my invention',
and in what manner the same is to be performed, I declare that what I claim is :-
1. The herein described construction of brake gear, consisting of a drum or
barrel fixed to the revolving mechanism to be acted upon and surrounded by an
elastic helically coiled band or rod of any suitable section, so arranged that by
putting a strain upon one or both ends of the coiled band it is tightened up on the
drum, and thereby stops or retards the rotation thereof and of the shaft or wheel
to which it is connected.
2. The use of the elastic helically coiled band referred to in the preceding claim
in all cases where it is desired to produce a rapid and energetic brake action either
for the rolling stock of railways, tramways, common road vehicles apparatus for
inclined planes, in mines, and the like, substantially as herein described.
3. The various herein described arrangeinents whereby the elastic helically coiled
band referred to in the first claim, may be applied for working brakes either by
hand or automatically by connection with the buffers and draw bar.
4. The various herein described arrangements whereby the elastic coiled bands
are applied with the ordinary coupling, and buffer and draw bar gear, the said
coiled bands being actuated by special rods or bars connected with oppositely acting
springs, which rods may be actuated separately and directly, or which may be
connected with the rods of the contiguous carriages, so as to allow of all the brakes
or a group thereof being actuated simultaneously, as set forth with reference to
Figs. 29, 30 and 31 of the drawings.
5. The arrangement of brake gear herein described with reference to Figs. 32
and 33 in which the movement of the draw hooks is utilised in combination with a
counter weight or equivalent means for applying the coiled band upon or slacking
it from the drum.
6. The arrangement of brake gear herein described with reference to Figs. 34
and 35 wherein the brakes are actuated by means of a continuous draw bar with
springs serving both as draw and buffer springs, and arranged with an initial
strain and acting in opposition to each other, so that a slight strain upon the one
or the other will cause the requisite movement of the drawbar.
7. Actuating the brake gear referred to in the preceding claim by means
mechanism arranged on the tender as shewn at Figs. 36 and 37, whereby the
driver can act upon the coupling bar even when the train is at rest or generally
when no steam is admitted to the engine.
8. The arrangements herein' described whereby the coiled band is brought into
action by the application of rollers to the wheel tyres."

page_text: 9. The arrangement described with reference to Figs. 38 and .39 wherein a
continuous drawbar is caused to bring one or the other of two rollers into action
on opposite sides of the axle, the said rollers having barrels on which are wound
the helically coiled bands.
10. The herein described arrangements whereby the helically coiled bands are
made to operate whether the drum is caused to rotate in one direction or in the
other.