Improvements in Devices Employed in Taking up the Slack in the Brake Mechanism of Railway Cars and similar Vehicles.
Year: 1896

page_text: Improvements in Devices Employed in Taking up the Slack in the
Brake Mechanism of Railway Cars and similar Vehicles.
I, MATTHEW JAMES GRIER, of 1531 Spruce Street, in the City of Philadelphia,
State of Pennsylvania, United States of America, Physician, do hereby declare the
nature of this invention to be as follows:-
The object of my invention is to provide the braking mechanism of railway cars
and other vehicles with means for automatically taking up the slack occasioned
by various causes such as the wear of the brake shoes and the stretching of the
rods. To accomplish this I use in connection with the ordinary levers
of the braking mechanism known respectively as the "live" and "dead" levers,.
or with the brake beams in certain classes of trucks, an interposed lever, which,
by the action of the take up mechanism, changes its position bodily on the truck,
and which for convenience I call a "walking lever." This introduced lever,
when used in connection with the ordinary railway car truck is so connected with
the brake beam levers that at the time of application of power to the brakes, both
of the said brake beam levers will be put into action at the same moment, thus
making them both acting or "live" levers, in contradistinction to the ordinary-
method of operation in which one lever is active (live) and the other is relatively.
passive (dead).
One of the brake beam levers is connected with one end of the walking lever
and the other brake beam lever is connected with the opposite end of the same.
The walking lever has two fulcra, neither of which is fixed, these fulcra alter-
nating in their functions according as power is applied to the brakes, or the brakes
are released. If the power be applied to the walking lever it is transmitted
directly to the brake beam levers, or if applied first to one of the brake beam levers,
it is transmitted to the walking lever and thence to the opposite brake beam
lever.
The object of the walking lever is partly to put both brake beam levers into
action at the same time, thus reducing the thrust of the piston rod of the brake
cylinder, and further to assist in taking up the slack due to wear and tear of the
brake mechanism, to maintain the various positions of one or both brake beam
levers in taking up the slack and to automatically permit of free movement of the
car wheels when the brakes are released. To take up any existing slack in the
brake gear it is necessary that the advance movement of the brake beam levers
should be wholly or partially maintained, hence I prefer to use for this purpose a
pair of racks which may both be carried by the walking lever or one of which
D

page_text: may be carried by the walking lever the other being carried by one of the brake
beam levers. The preferable plan is to attach both racks to the walking lever at
points between the points of attachment of the rods which connect the said walking
lever to the brake beam levers. The racks are loosely attached in order to permit
free movement of the walking lever and these attachments constitute the fulcra
of the said walking lever, so that if it be moved in one direction one attachment
becomes the fulcrum controlling that particular movement, its rack remaining
stationary, while the other rack is advanced as much as the slack will permit, its
teeth engaging with the retainer and holding it in the new position. When the
walking lever is moved in the opposite direction it reverses the action of the racks,
the one which was formerly moved now being stationary and the one which was
formerly stationary now being moved, and having its movement held by the
retainer. In consequence of this construction intermittent movements of advance
are given to the walking lever and the brake beam levers are correspondingly
affected so as to take up the slack.
In order to insure a straight line advance of the walking lever in its forward or
backward movements a slotted guide is desirable, this guide preferably controlling
one of the rack pins.
The counter force in opposition to the pull of the rod of the brake cylinder or
hand brake, may be the weight of the brake-shoes and beams, the latter being so
hung as to normally fall away from the wheels, or a spring or springs may be
employed for this purpose.
The details of the device may be varied as may be demanded by the particular
vehicles to which said device is attached, and the invention is not limited in its
application to brakes such as are used upon the cars of steam railways, but may,
by slight modifications or re-arrangements of parts, be applied with equally good
results, to the brake structures used upon tram cars.
Having thus given a general description of my invention and its purpose I will
in order to make the nature of the invention quite clear describe a manner in
which it may be carried into effect.
The frame of the truck, the axles, the wheels, the brake beams, the brake shoes,
the hanger links and the retracting springs may be of any suitable description,
for example they may be similar to those used upon the standard trucks now in
use on cars constructed upon the American system.
Each brake beam has a projecting lug or bracket to which is hung a lever, that
of one brake beam being hereinafter referred to as the "first" lever and that of the
other brake beam being referred to as the "second" lever, the short arms of these
levers being connected by a rod, while the long arm of the first lever is connected
by a rod to one end of a third lever, the opposite end of the latter being connected
by a rod to the long arm of the second lever.
This third lever is the aforesaid interposed or walking lever, and it is connected
to the rod which leads to the piston rod of the power cylinder, to the chain of the
hand brake, or to any other suitable form of power applying device.
Hung to the walking lever are two rack bars hereinafter referred to as the
"first" and "second" rack bars respectively which are adapted to engage with the
opposite legs of a yoke against which they are pressed by an interposed spring so
that the said legs of the yoke serve as retainers for the respective rack bars.
The pin which attaches the second rack bar to the walking lever enters a slot
in a plate which is secured to the truck frame in any convenient position, this
plate being widened or enlarged at one end so as to carry the yoke, so that the
application or removal of the slack adjusting device can be very readily effected.
When power is applied to the brake rod it tends to move the walking lever in
a direction such as to impart a forward pull upon the second rack bar. The said
rack bar is prevented from moving in this direction, however, by reason of its
engagement with the yoke, hence the attaching pin of said rack bar becomes the
fulcrum for the walking lever, and the first rack bar is moved in a forward
direction. These movements continue until they are arrested by the application

page_text: of the brake shoes to the wheels or until the completion of the stroke of the power
device, if the slack of the brake gear be greater than can be taken up by one
movement.
When the pull upon the brake rod ceases the brake beams are retracted by the
action of the brake beam springs, or in the absence of the latter, by the action of
gravity, or by the action of a spring on the walking lever, and the latter lever
is thereby moved in a direction the reverse of that before described.
The pivot pin of the first rack bar now becomes the fulcrum of the walking lever
and the second rack bar is advanced and retained in its position of advancement by
engagement with the yoke, and fhese operations are repeated on each operation
of the power device for applying the brakes, the result being that the walking
lever gradually advances or travels forward until the slack in the gear is entirely
taken up and the shoes on each release of the brakes only fall far enough away
from the wheels to free them from contact.
Various modifications can be made in the arrangements according to my inven-
tion, for example:-
The walking lever may carry a pair of pawls, engaging with racks formed
on the opposite edges of a plate which has the slot therein for the guidance of a pin
on the lever, the operation of this device being substantially similar in effect to
that of the device, hereinbefore described, or a walking lever having only ono
rack bar may be employed, the other rack bar being carried by the upper end of
the first lever and engaging with a suitable retainer on the truck frame.
In this case the second fulcrum of the walking lever is at the point of attachment
of the rod which connects the said lever to the first lever, the point of attachment
of the rack bar serving as the falerum when power is applied and the point of
attachment of the rod serving as the fulcrum for the walking lever when the
brakes are released.
My invention is also applicable to the braking mechanism used upon the trucks
of tram cars. In a known form of such braking mechanism the brake beam
carrying the shoes for the wheels at one end of the truck is connected by suitable
rods to a beam carrying the shoes for the wheels at the other end of the truck, the
brakes being applied as the beams are drawn towards each other. In applying
my invention to such a truck I do not directly connect the brake beams as usual,
but I connect the second brake beam by rods to a supplementary beam adjacent to
the said first brake beam.
A lever hung to a lug on the first brake beam is connected by a link to a
walking lever which carries a pair of rack bars adapted to engage with a yoke ou
a plato secured to the supplementary beam.
When the brake rod is pulled, therefore, the first brake beam is thrust forward
and the link is pulled in the reverse direction, thereby imparting corresponding
movement to the walking lever and causing one rack bar to be thrust forward so
as to cause an advance of its pivot which becomes the fulcrum for the walking
lever on the release of the brakes. The latter movement causes the other rack
bar to be thrust forward and these movements continue until the brake beams are
drawn together sufficiently to take up the slack.
In another construction the first brake beam carries a lever which is connected
by a link directly to the supplementary heam, the latter being outside of the brake
beam instead of inside of it, and being connected to the brake beam at the opposite
end of the truck by suitable rods.
A lever hung to the first brake beam is connected by rods to a walking lever
which is suitably guided upon a plate secured to the truck frame and carries two
rack bars engaging with a yoke on the said plate. In this case, as before, the
walking lever advances on the successive operations of the brake mechanism so as
to have the effect of drawing the first brake beam nearer to the wheels and forcing
the supplementary beam away from the said first brake heam so as to effect a
corresponding approach of the opposite brake beam to its wheels, the result being
that the slack in the brake gear will be taken up as soon as it becomes sufficient

page_text: in extent to permit a movement of the primary acting rack bar of the walking
lever to the extent of a single tooth thereof.
Dated this 14th day of November 1896.
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.
Improvements in Devices Employed in Taking up the Slack in the
Brake Mechanism of Railway Cars and similar Vehicles.
I, MATTHEW JAMES GRIER, of 1531 Spruce Street, in the City of Philadelphia,
State of Pennsylvania, United States of America, Physician, 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:-
The object of my invention is to provide the braking mechanism of railway cars
and other vehicles with means for automatically taking up the slack occasioned
by various causes such as the wear of the brake shoes, and the stretching of the
rods, and the like. To accomplish this, I use, in connection with the ordinary levers
of the braking mechanism known, respectively, as the "live" and "dead" levers,
or with the brake beams in certain classes of trucks, an interposed lever, which,
by the action of the take up mechanism, changes its position bodily on the truck,
and which for convenience I call a "walking lever." This interposed lever,
when used in connection with the ordinary railway car truck, is so connected with
the brake beam levers that at the time of application of power to the brakes both
of the said brake beam levers will be put into action at the same moment, thus
making them both acting or live levers, in contradistinction to the ordinary
method of operation in which one lever is active (live) and the other is relatively
passive (dead). One of the brake beam levers is connected with one end of the
walking lever, and the other brake beam lever is connected with the opposite end
of the same. The walking lever has two fulcra, neither of which is fixed, these
fulcra alternating in their functions according as power is applied to the brakes
or the brakes are released. If the power be applied to the walking lever, it is
transmitted directly to the brake beam levers, or if applied first to one of the
brake beam levers it is transmitted to the walking lever and thence to the oppo-
site brake beam lever. The object of the walking lever is partly to put both
brake beam levers into action at the same time, thus reducing the thrust of the
piston rod of the brake cylinder, and further to assist in taking up the slack due
to wear and tear of the brake mechanism, to maintain the various positions of
one or both brake beam levers in taking up the slack, and to automatically permit
of free movement of the car wheels when the brakes are released. To take up
any existing slack in the brake gear, it is necessary that the advance movement
of the brake beam levers should be wholly or partially maintained. I prefer to
use for this purpose a pair of racks which may both be carried by the walking
lever, or one of which may be carried by the walking lever the other being
carried by one of the brake beam levers. The preferable plan is to attach both
racks to the walking lever at points between the points of attachment of the rods
which connect the said walking lever to the brake beam levers. The racks are
loosely attached in order to permit free movement of the walking lever, and these
attachments constitute the fulcra of the said walking lever, so that if it be moved
in one direction one attachment becomes the fulcrum controlling that particular
movement, its rack remaining stationary, while the other rack is advanced as

page_text: much as the slack will permit, its teeth engaging with the retainer and holding
it in the new position. When the walking lever is moved in the opposite
direction, it reverses the action of the racks, the one which was formerly moved
now being stationary and the one which was formerly stationary now being
moved and having its movement held by the retainer. In consequence of this
construction intermittent movements of advance are given to the walking lever,
and the brake beam levers are correspondingly affected, so as to take up the
slack.
In order to insure a straight line advance of the walking lever in its forward or
backward movements, a slotted guide is desirable, this guide preferably con-
trolling one of the rack pins.
The details of the device may be varied as may be demanded by the particular
vehicles to which the said device is attached, and the invention is not limited
in its application to brakes such as are used upon steam driven cars, but may
by slight modifications or arrangement of parts be applied with equally good results
to the brake structures used upon cars otherwise driven.
Having thus given a general description of my invention and its purpose, I
will now describe the same more in detail, referring to the accompanying
drawings, in which :-
Figure 1 is a perspective view of part of an ordinary four wheeled truck having
braking mechanism provided with slack adjusting devices in accordance with
my invention;
Figures 2 and 3 are plan views of the same with the parts in different positions
and
2
Figures 4, 5, 6 and 7, are views illustrating various modifications of my
invention.
In Figure 1, the frame of the truck is represented at 1, the axles being shewn
at 2, and the wheels at 3, while the brake beams are represented at 4, enough of
each brake beam being shewn to illustrate the brake shoe 5, the hanger link 6
and the retracting spring 7. Each brake beam has a projecting lug or bracket 4*,
to which is hung a lever, that of one brake beam being represented at 8 and that
of the other brake beam at 9, the short arms of these levers being connected by
a rod 10, while the long arm of the lever 8 is connected by a rod 11 to one end
of a lever 12, the opposite end of the latter lever being connected by a rod 13 to
the long arm of the lever 9. This lever 12 is the interposed or walking lever to
which reference has heretofore been made, and it is in the present instance
connected to the rod 14, which leads to the piston rod of the power cylinder, to
the chain of the hand brake, or to any other form of power applying device.
Hung to the lever 12 are two rack bars 15 and 16, which are adapted to engage
with the opposite legs of a yoke 17, against which they are pressed by an inter-
posed spring 18, so that the said legs of the yoke serve as retainers for the
respective rack bars.
The pin which attaches the rack bar 16 to the lever 12 enters a slot 19 in a
plate 20, which is secured to the truck frame in any convenient position, this
plate being widened or enlarged at one end so as to carry the yoke 17, so that
the application or removal of the slack adjusting device can be very readily
effected.
When power is applied to the rod 14, it tends to move the lever 12 in the
direction of the arrow, Figure 2, and hence imparts a pull upon the rack bar, 16 in
the direction of the arrow. (Shewn in Figure 2.) As the said rack bar is pre-
vented from moving in this direction, however, by reason of its engagement with
the yoke 17, the attaching pin of the said rack bar becomes the fulcrum for the
lever 12. Hence the rods 11 and 13 are drawn in the direction of their respec-
tive arrows, Figure 2, and the rack bar 15 is moved in the direction of its arrow.
These movements continue until they are arrested by the application of the
brake shoes to the wheels, or until the completion of the stroke of the power

page_text: device, if the slack of the brake gear is greater than can be taken up by one
movement. When the pull upon the rod 14 ceases, the brake beams are retracted
by the action of the brake beam springs 7, or, in the absence of the latter, by
the action of gravity, and the lever 12 is moved in a direction the reverse of that
indicated by the arrow in Figure 2. The pivot pin of the. rack bar 15 now
becomes the fulcrum of the lever and the rack bar 16 is advanced and retained
in its position of advancement by engagement with the yoke 17, and these opera-
tions are repeated on each operation of the power device for applying the brakes,
the result being that the lever 12 gradually advances or travels forward until the
slack in the gear is entirely taken up and the shoes on each release of the brakes
only fall far enough away from the wheels to free them from contact. Figure 3
shews the position of the parts after an excessive amount of slack has been
taken up.
Various modifications are possible within the scope of my invention, and some of
these modifications I will now proceed to describe.
In the construction shewn in Figure 4 the lever 12 carries a pair of pawls 15*
and 16, these pawls engaging with racks 15 and 16 formed on the opposite
edges of a plate 20", which has the slot therein for the guidance of a pin on the
lever, the operation of this device being substantially similar in effect to that
of the device shewn in Figures 1 and 2.
In the construction shewn in Figure 5 a lever 12b, having only one rack 16°, is
employed, the other rack 15 being carried by the upper end of the lever 8 and
engaging with a suitable retainer on the truck frame. In this case the second
fulcrum of the lever 12b is at the point of attachment of the rod 11, which
connects the said lever to the lever 8, the point of attachment of the rack bar 16
serving as the fulcrum when power is applied, and the point of attachment of
the rod 11 serving as the fulcrum for the lever 120 when the brakes are released.
In Figures 6 and 7 I have shewn the application of my invention to two well
known forms of street car brake mechanism. In the construction shewn in
Figure 6 the brake beam for the wheels at one end of the truck is represented at 21,
the beam having brake shoes for the wheels at the other end of the truck not
being shewn, but being in practice connected by rods 22 to a beam 23. A lever 24
is hung to a lug on the beam 21 and is connected by a link 25 to a walking
lever 124, which carries a pair of rack bars 15 and 16, adapted to engage with a
yoke 17 on a plate 20d, secured to the beam 23. When the brake rod 14 is
pulled in the direction of the arrow, the brake beam 21 is thrust forward in the
direction of its arrow and the link 25 is pulled in the reverse direction, thereby
imparting corresponding movement of the lever 12 and causing the rack bar 150
to be thrust forward in the direction of its arrow, so as to cause an advance of its
pivot, which becomes the fulcrum for the lever 12 on the release of the brakes.
This movement causes the rack bar 16d to be thrust forward and these move-
ments continue until the beams 21 and 23 are drawn together sufficiently to take
up the slack. In the construction shewn in Figure 7 the brake beam 21 carries
a lever 24, which is connected by a link 25 directly to the beam 23, the latter
being outside of the brake beam 21 instead of inside of the same, as in Figure 6,
and being connected to the brake beam at the opposite end of the truck by rods 22.
In this case the lever 24" is connected by rods 26 to a walking lever 12, which is
suitably guided upon a plate 20, secured to the truck frame, and carries two
rack bars 15 and 16, engaging with a yoke 17 on the said plate. In this case,
as before, the lever 12 advances on the successive operations of the brake
mechanism, so as to have the effect of drawing the brake beam 21" nearer to the
wheels and forcing the beam 23" away from the beam 21ª, so as to effect a corre-
sponding approach of the opposite brake beam to its wheels, the result being that the
slack in the brake gear will be taken up as soon as it becomes sufficient in extent
to permit a movement of the primary acting rack bar of the walking lever to the
extent of a single tooth of the same.

page_text: Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed, I declare that what I
claim is:-
1. Slack adjusting mechanism for railway car brakes, consisting of a lever
independent of the brake beams or brake beam levers of the car, but having con-
nection therewith so as to be operated on each application of the brakes, the said
lever being combined with a pair of racks and having two alternately acting
fulcrums whereby, in case of undue slack in the gear, there is on the application
of the brakes an advance of one rack, and on the release of the brakes, an advance
of the other rack, substantially as specified.
2. Slack adjusting mechanism for car brakes, consisting of a lever independent
of the brake beams or brake beam levers, but having connection therewith,
whereby it is operated on each application of the brakes, the said lever having
alternately acting fulcrums and being combined with a pair of racks, one of
which, in case of undue slack in the gear is advanced when the brakes are applied,
and the other when the brakes are released, the said lever being guided so that
its advance movements are in straight lines, substantially as specified.
3. Slack adjusting mechanism for car brakes, consisting of a lever independent
of the brake beams or brake beam levers, but having connection therewith,
and carrying a pair of racks each engaging with a suitable retainer, the said racks
being constructed and disposed as described whereby the connection of first one
rack and then that of the other rack, with the lever, constitutes the fulcrum on
which said lever swings, substantially as specified.
4. Slack adjusting mechanism for car brakes, consisting of a lever connected
at one end to the brake beam lever at one end of the truck, and at the other end
to the brake beam lever at the opposite end of the truck, the said lever having
alternately acting fulcrums and being combined with racks engaged by suitable
retainers and so disposed in respect to the lever that, in case of undue slack in
the gear one rack will be advanced by movement of the lever in one direction and
the other by movement of the lever in the opposite direction, substantially as
specified.
T
1005
JOHNSONS & WILLCOX,
47 Lincoln's Inn Fields, London, W.C., Agents.