Improvements in Brakes for Vehicles, applicable also to Machinery.
Year: 1894

page_text: Date of Application, 31st Jan., 1894-Accepted, 5th May, 1894
COMPLETE SPECIFICATION.
Improvements in Brakes for Vehicles, applicable also to Machinery.
We, ERNST HECHT of 6 Berlinerstrasse Tempelhof in the Empire of Germany,
Carpenter, PAUL RASCHE of 101 Berlinerstrasse in Tempelhof aforesaid,
Wheelwright, and BERTHOLD KRUG of 20 Berlinerstrasse in Tempelhof aforesaid,
Blacksmith, do hereby declare the nature of this invention and in what manner
the same is to be performed to be particularly described and ascertained in and
by the following statement :-
This invention relates to an improved brake apparatus for vehicles which has
for its object providing for the application of the brake in a convenient and safe
manner with a minimum expenditure of power.
We attain this end by the apparatus illustrated by the accompanying drawing in
which :-
--
Figure is a view in plan of the apparatus applied to an ordinary road
vehicle.
Figure 2 is a view in side elevation-partly in section-of the operating
mechanism.
Figures 3, 4 and 5 are views showing the details of the construction of this
operating mechanism.
Figures 6 and 7 are views showing a modification in the arrangement of the
said mechanism.
Figures 8 and 9 are further views showing details of the construction of the
operating mechanism.
Figure 10 is a broken view in side elevation showing a modification of the brake
gear.
Figures 11 and 12 are views of an improved form of brake shoe.
Throughout the views similar parts are marked with like letters of reference.
All brakes are with the exception of pneumatic brakes operated either by means
of a crank or by means of a lever. When a brake is operated by means of a crank,
the person who wishes to apply the brake is compelled in order to overcome the
dead points of the crank axle to change his position, which is especially dangerous
when the brake has to be applied in case of danger, as in such cases the person
is often obliged to divert his attention from the mere application of the brake.
When the brake is operated by means of levers, the person who has to put
the apparatus into operation must for that purpose change his position. In fact
experience has shown that even with properly constructed lever brakes numerous
accidents are caused by the lever flying back. Now all these drawbacks are
obviated by the employment of a brake as bereinafter described, because the said
brake is operated, not by means of cranks or levers, but by simply drawing a
band from off a drum.
The principle of this brake apparatus consists in that a band wound on a drum
is drawn off when it is desired to apply the brake which causes the aforesaid
druin to rotate. Connected with this drum is another drum of smaller diameter
which is consequently also caused to rotate and thereby to wind up a band
which is connected to the brake gear and serves to press the brake blocks against
the rims of the wheels.
The most simple arrangement of this type of brake is that illustrated by
Figures 1 and 2 in which the band a is attached at one end to the periphery of

page_text: C
the drum A adapted to rotate about the axis of the shaft c; the band a being
wound on the drum in the direction of the arrow, whilst the band bis fastened
either to a second drum B concentric with A, or to the shaft c itself. The band a
is provided with a ring d or other handle at its free end. On pulling the handle,
the band a becomes unwound and causes the drum A to revolve, which causes
the drum B connected therewith also to revolve, so that the band is wound up,
and as the said band is connected at e to the brake gear it operates it.
In some cases, for example in carriages it may be advisable to be able to
actuate the brake from various places. For this purpose a second band a¹ is
wound over or next to the band a on the drum A, and it is provided at its free
end with a handle such as d¹. This band is led over suitable guide pulleys to
any desired point.
In order to be able to apply the brake with a minimum exertion of power, the
diameter of the drum B is made very small in proportion to that of A, the
consequence of which is that the band a must he pulled out to a great distance
in order that the band b may become wound several times around the drum B.
The brake shoe will generally be at a greater or less distance from the periphery
of the wheel, but in order that a brake shall work properly, it is important that
the brake shoe shall be easily and quickly applied to the periphery of the wheel,
and then be pressed against the same with a gradually increasing force. This is
effected in a simple manner according to the present invention by making the
radius of the drum B, that is to say the leverage of the load, greater at the
corresponding point. This is done by means of the bolt f which is screwed into
the drum A parallel to the shaft c, and the operation of which is clearly shown in
Figure 2. The brake is restored to its original position by means of the springs g,
when the pull
on d or d¹ ceases; the band b then becoming unwound, and the
bands a and a becoming wound up.
Unintentional release of the brake is prevented by the ratchet wheel h and the
panli. The ratchet wheel may be formed on or fixed to the drum A, or it may
when A is keyed on the shaft c, also be fastened on the said shaft.
The pawl is mounted independently of the drum and it is thrown out of
engagement by a cord k or k', when the braking action is to be diminished or
stopped.
By properly proportioning the diameters of the drums and the amount of
eccentricity of the bolt f, the length of band a to be wound off can be easily kept
within proper limits.
After a long period of use the band or strap 6 may stretch, and the brake
shoes may become worn so that the strap a will have to be pulled out to a corre-
spondingly greater extent in order to apply the brakes properly. Now in order
to remedy this drawback, the drum A is made as a hollow cylinder, and in the
said hollow cylinder there is arranged the hereinafter described device which winds
the band automatically to such an extent on to the drum B that the length of
band a to be drawn off is always of the same length, and the brake shoes are
always kept at one fixed distance from the periphery of the wheel.
In using this device, the drum A is mounted so as to be capable of easily
rotating on the shaft c, whilst the ratchet wheel and the drum B are keyed or
bolted on to the said shaft. A second ratchet wheel ¹ Figures 3, 4, and 5, is
keyed on to the shaft c, and serves to transmit the rotation of the drum A to the
said shaft through the medium of the pawl m and the bolt fixed in the wall w.
Next to the pawl m is another pawl n so arranged that it can be moved concen-
trically. This pawl is guided in the slot o by means of the pin p which is also
screwed into the wall w. The string F keeps the pawl n normally engaged with
the ratchet wheel h¹. The angle piece W serves as a support for the shaft c and
also to limit the rotation of the drum through the pawl 'n carrying a projection 7.
When the brake is placed out of operation, both drums are rotated backwards by
the springs g, g, to such an extent that the projection r comes to bear against the
lower leg of the angle piece W.

page_text: When the brake is applied, the brake shoes should find sufficient friction against
the peripheries of the wheels before the projection r comes in contact with the upper
limb of W.
When the brake shoes are worn away, or the band 6 has become too long, then
a must be pulled further out in order to be able to produce the proper braking
effect. This will at last bring the projection r into the notch s in the upper limb
of W, and the pawl n will thus be thrown out of engagement. If the band a be
pulled further out, the entire brake apparatus still operates through the pawl m
(which is still in engagement), whilst the pawl n in the arrangement shown in
Figure 4, is kept back, and the spring F is thus tightened. On releasing the strap,
the pawl n and the shaft c which is held by the ratchet wheel h and the pawl i will
remain stationary, whilst the drum A will be rotated backwards by the spring F
pressing against the pin to an amount equal to the teeth skipped by the pawl n
which was out of engagement. The return of the drum A must also be followed
by the pawl m which therefore moves back as many teeth as the spring F has
rotated the drum backwards.
In order to be able to clearly understand the series of operations in this automatic
adjusting device, it should be noted that the one band is wound on in a right hand
direction, and the other band in a left hand direction, so that the band 6 will always
be unwound when a is being wound up, and vice versa. The mechanism herein before
described thus allows of winding up the band a without unwinding the band b,
when that portion of the band b to be wound up has become unnecessarily long.
When the brake is once applied, the aforesaid mechanism cannot act any longer,
because the brake then is able to operate further in the usual manner, thus showing
that the strap b can never be wound up too far. Therefore when this device is
used, the case of the brake being unable to act can never happen.
In renewing the brake blocks the band 6 must be removed from the drum B.
This is effected by pressing the pawl n, with the aid of the projection r, against
the periphery of the drum, so that the nose t bears against the projection u of the
pawl n and also places the latter out of engagement. By pulling on the cord or
line k or k¹ the pawl i is placed out of engagement, so that the springs 9, 9, can act
and draw the band b away to such an extent as to leave sufficient space between
the periphery of the wheel and the brake shoe, so that the brake blocks fixed to
the latter can be renewed.
Local conditions may frequently render it necessary to arrange the brake with
its axis vertical. This may often be the case with tramways for which this brake
apparatus is especially suited. In such cases the operating mechanism may be
arranged in a pot-like casing on the bottom of the vehicle, as shown in Figures 6
and 7. The several parts of the brake remain exactly the same, with the exception
that the angle-piece W is replaced by a recess w in the bottom of the casing.
The handle of the strap a may in the case of road vehicles be fastened either to
the splash board of the carriage or preferably to the waist belt of the driver, so
that the latter in case of its being necessary to put on the brake shall not even
require his hands but can apply the brake by merely leaning his body backwards.
In order to render the brake perfect in every respect, the brake gear has also
been substantially improved.
In almost all brake apparatus the pivot C-Figure 1-must be located inde-
pendently of the wheel axle. Now the great advantage of the present invention
consists in being able to lead the pulling strap a and also the operating band to
any desired point by means of guide pulleys, thereby enabling the brake gear to
be constructed in any desired suitable manner without having to be limited by the
consideration of a rigid connecting or operating rod. The pivots C are therefore
fixed to the axle brackets carrying the springs thus entirely preventing the injurious
twisting of the springs when applying the brake.
Figure 10 shows a modification of the brake herein before described, by which
the whole apparatus can be operated by an extremely gentle pull on the band a,
and also that excessive pressure on the axle that often causes the latter to become

page_text: bent and twisted when applying the brake is entirely obviated. This modification
may be properly termed an indirect-acting friction brake, and it will be found very
suitable not only for railways and heavy vehicles in general, but also for hoisting
machinery etc.
Referring to Figure 10. Bolted to the spring bracket or to any other fixed part
of the wheel axle or of the underframe, is a plate L which carries the pivot of the
lever H. The hub N of the wheel is formed with a grooved recess at its periphery,
into which is loosely laid an elastic band M which is smooth at its outer surface
and is furnished with an eye M'. The band M is fitted on its inner surface with a
friction-producing surface formed by screwing on small brake blocks M2 or their
equivalents which extend for about four-fifths round the periphery of the hub of
the wheel. A band O of steel of the width of the recess is fastened at both its
ends to the lever H by bolts, and is formed at the proper place with slots O¹ to
allow of the eye M¹ passing through. When the brake is "off," the band O is
held by the pull rod D' in such a manner that it surrounds the wheel hub but
loosely. When the rod D' is pulled, to apply the brake the steel band O and
consequently also the band M is pressed against the periphery of the hub of the
wheel, so that the band M is obliged to follow the motion of the hub. The rod G
which is fastened to the eye M¹ and is connected with the brake shoe in a manner
to be hereinafter described is pulled towards the wheel axle, whereby the brake
shoe is pressed against the periphery of the wheel; but as the band M is held
tight so that the bands O and M form one, the hub N is also braked. In this
arrangement the friction on the periphery of the wheel increases in direct
proportion with the friction produced on the hub of the wheel, and only a small
exertion of power is necessary to operate the brake, because the momentum of the
rotating hub of the wheel aids in operating the brake.
When it is desired to brake the periphery of the wheel from both sides, the
band M which carries the small brake blocks is divided, and each of these portions
is provided with an eye M', to which a brake rod G is attached.
By the use of the movable brake band M the direction of rotation of the hub
becomes immaterial, which is of great importance, for instance in the case of a
vehicle proceeding up hill and suddenly starting to move backwards.
If a brake block is to act properly and not become worn on one side, it is necessary
that it should be pressed with its entire frictional surface against the periphery of
the wheel. To attain this end we mount the brake shoe in the ordinary manner on
a carrying pin Z. The back of the brake shoe is recessed and is adapted to receive
a hinge-like clamping ring R-Figures 11 and 12-which is clamped on the
carrying pin Z by means of the screw in such a manner that a force almost equal
to the braking power is requisite to cause said ring to turn the said pin Z being
arranged to rotate freely in the sides of the back of the shoe. When the brake
shoe which swings about a centre situated on the carriage body, is pressed against
the periphery of the wheel, the shoe is compelled to assume such a position that it
acts against the wheel with its entire frictional surface. When the brake shoe is
allowed to swing back, it would place itself obliquely, and to prevent this the
ring R has fixed to it a spring a which always keeps the brake shoe in the proper
position.
We wish it to be particularly understood that we do not limit ourselves to
the precise details of construction herein before described and illustrated by the
accompanying drawing, but that we hold ourselves at liberty to make such changes
and alterations as fairly fall within the spirit and scope of our invention.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed, we declare that what we
claim is :-
1. The respective combination of parts forming our improved brake apparatus
for vehicle wheels, substantially as hereinbefore respectively described and illustrated
by the accompanying drawing.

page_text: 2. An apparatus for applying brakes to the wheels of road vehicles consisting
essentially of a drum such as A, of a drum such as B formed on or attached to the
drum A, of a band such as a wound on the drum A and having a handle such as d
at its free end, and of a band such as wound on the drum B and connected at its
other end to the brake gear as set forth.
3. In a brake apparatus, the use of a band such as a wound on a drum such
as A which band on being drawn off the said drum causes a second drum such as B
to rotate and wind up a band such as 6 connected to and operating the brake gear,.
as set forth.
4. In a brake apparatus the use of two or more bands such as a and a' wound on
the same drum A to provide for the application of the brake from different points,
as set forth.
5. In a brake apparatus such as is specified in Claim 2, increasing the effective
radius of the drum B at one point by means of a pin or projection such as f, for the
purpose of suitably varying the load leverage of the brake at the proper moment,
as set forth.
6. In a brake apparatus such as is specified in Claim 2, the device for auto-.
matically winding the pulling band b on to the drum B to the required extent to
cause the brake shoes to retain a fixed position with respect to the periphery of
the wheel, consisting of a movable pawl such as m of a ratchet wheel such as
fixed on the shaft c carrying the drums A and B, and of a spring such as F adapted
to bear at one end against the said pawl and at the other end against a projection
such as on the drum A, as set forth.
7. In a brake apparatus the use of rocking bars pivotted at C on the wheel axle,
one arm of each of the said rocking bars being connected with the operating
band 6 or its equivalent through suitable connections, and the other arm of each of
the rocking bars being connected with the levers carrying brake blocks by means
of suitable connections, as and for the purpose set forth.
8. A brake gear consisting essentially of a band such as O loosely encircling the
hub of the wheel, of a loose band M located under the band O and adapted to
engage with and to be readily moved around the hub, of a rod such as G connecting
the eye M on the band M with the brake shoe, of a lever such as H and an
operating rod such as D¹, all combined arranged and adapted to operate as set forth.
9. In a brake shoe the use of a clamping friction ring such as R and of a spring
such as a, to keep the brake shoe in its proper position relative to the periphery of
the wheel as set forth.
1004
ROBERT E. PHILLIPS, M.I.M.E.,
Consulting Engineer and Patent Agent,
70, Chancery Lane, London, W.C., Associate Agent..