An Improved Brake Slack Adjuster for Railway and like Vehicles.
Year: 1895

page_text: Date of Application, 14th Mar., 1895-Accepted, 27th Apr., 1895
COMPLETE SPECIFICATION.
An Improved Brake Slack Adjuster for Railway and like
Vehicles.
We, FRANK ROBINSON, of 41 Summer Street, Bangor, Maine, Mechanic, and
JAMES HALE SEWALL, of 291 Cumberland Street, Portland, Maine, Manu-
facturer, both in the United States of America, 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 invention consists in the construction of an automatic slack adjuster applied
between the cylinder levers, and so constructed that the adjustment is effected
without connecting the adjusting devices to a stationary part of the car.
The invention particularly consists in the construction of a two-part fulcrum rod
having a central take-up connection, and a two-part adjustment rod, likewise
connecting these two levers beyond the fulcrum rod, having a take up connection, one
cylinder lever having a limited amount of lost motion or a play on the adjustment
rod, the parts being so constructed and combined as to maintain a substantially
constant travel of the air brake piston at all times, regardless of the wear of the
shoes, all as more fully hereinafter described.
In the drawings,
Fig. 1 is a plan view of the cylinder and cylinder levers showing the invention
applied thereto.
Fig. 2 is a side elevation, partly in section, of the adjustment rod.
Fig. 3 is a side elevation of a take-up connection of slightly modified form.
Fig. 4 is a section therethrough.
Figs. 5 and 6 are diagram plans showing the different positions of the parts in
operation.
A is the air brake cylinder, B and C are the two cylinder levers, the lever B
being pivoted to the bracket D at one end of the cylinder and the cylinder lever C
being connected to the piston rod E. These levers at their ends have connected to
them the usual rods which operate brakes at the opposite ends of the cars in the
well known manner.
The two levers are connected together at or near their middle by a tie-rod, which
we call the fulcrum rod. This fulerum rod is made in two parts F and F¹. On the
inner end of the section F is an open box like socket or guide G in which the end
of the section F of the rod slidingly engages. Upon the upper face of this section F
is formed a ratchet bar H.
I is a toothed block or pawl slidingly engaging in a vertical aperture in the
top of the box G on the section F' of the fulcrum rod, and I' is a spring acting
to hold this block in engagement with the ratchet bar H, as plainly shown in
Fig. 2.
This construction of take-up joint between the two members of the fulcrum rod
is especially desirable as the ratchet bar and pawl are entirely enclosed, so that
there is no danger of the dust or dirt interfering with their movement or the
positive engagement of the pawl with the ratchet bar.
At a point at or near the ends of the levers B and C is a rod made in two
sections J and J, their meeting ends overlapping and having a similar take up
connection. The section J is pivoted to the lever B. The section J' is provided
at its end with a loop or guideway K in which slidingly engages the lever C.
K' is a pin adapted to be engaged in any one of a series of apertures L through
[P Q17

page_text: the loop K and adapted to span the loop so as to lengthen or shorten the guideway
or slot in which the lever C may move.
Instead of the construction shown in Fig. 2, we may use the take up connection,
as shown in Figs. 3 and 4.
In this construction of take-up we employ a series of dogs M supported in trans-
verse grooves or sockets M' in the top of the box portion of the section J' engaging
with the ratchet bar on the section J.
N is a plate having vertical slots at the ends engaging with pins N' so as to
permit said plate to have a limited vertical movement, the upper edge of the plate
resting under the lower edge of the dogs M.
O is a cam journaled on an extension O' on the under side of the section J¹ and
which may be turned to actuate the plate N vertically, thereby lifting the dogs
out of engagement with a ratchet bar to permit the adjustment or disengagement of
the parts of the take up connection.
P is an end plate detachably secured in the section J¹ over the end of the
sockets M' and acting to hold the dogs in position against end displacement.
The parts being thus constructed their operation is as follows: In setting the
brake the parts are adjusted so that with the desired travel of the brake piston,
the brakes will be set. When so set, the lever C will move back and forth
within the loop K without striking the bent end thereof, or the pins K' at the
other end.
The length of this movement can be varied by adjusting the pin K' into the
different adjusting holes L.
In case the shoes wear so as to give too great a piston travel, the outer end of
the levers B and C approach each other, the lever C will strike the pin K¹ and the
take-up rod will thus be under compression at opposite ends between the two
cylinder levers, which will effect a sliding movement between the overlapping ends
of its two sections, thereby shortening that rod, the toothed block I engaging in
the ratchet bar will hold it in its adjusted position.
When the levers B and C return to their initial position, the lever C will strike
against the end of the loop K and thereby cause such lever to fulcrum thereon,
when the further inward movement of the piston rod E will act to put a compression
strain upon opposite ends of the fulcrum bar and shorten that in the same manner
as described for the adjustment bar.
When the piston is again actuated the fulcrum bar being shortened the slack will
have been taken up and the piston will make its usual and desired travel.
It is deemed especially desirable to apply the adjustment to the cylinder
levers, as it takes up the slack positively and is not affected by the wear of
the parts, springing of levers etc., requiring but a single adjuster for each car.
Another advantage of this construction is that it does not require any changes
to the brake apparatus as now ordinarily applied, simply the use of the two-part
fulcrum rod in place of the usual rigid rod, and the two part adjustment rod.
It can thus be applied to brake equipments now in use with practically no change
therein.
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 combination of the cylinder levers, a fulcrum rod having an intermediate
take-up, an adjustment rod extending between the levers beyond the fulcrum rod,
one end of said adjustment rod having a loose connection with the lever, and a
take-up in said adjustment rod.
2. The combination of the cylinder levers, a two part fulcrum rod, having a
ratchet and pawl connection at the meeting ends of the parts, a two part adjustment
rod pivoted at one end near the outer end of one lever, a loop or eye at the other
end through which the other lever engages, and a take-up," at the meeting ends
of the adjustment rod.

page_text: 3. The combination of the cylinder levers, a two part fulcruin rod having an
intermediate take-up, a two part adjustment rod having a similar take-up one end of
said rod being pivotally connected to one lever, a loop at the other end of the
adjustment rod through which the other lever passes, and a pin adapted to adjust
the length of the play of the lever in the loop.
4. In a device of the kind described, a take up connecting rod formed in two
parts, having overlapping ends, an open-ended box shaped sleeve at the inner end
of one part, a toothed bar at the inner end of the other part sliding into the sleeve,
and a pawl or series of dogs in the top of the sleeve adapted to engage the
ratchet bar.
5. In a device of the kind described, a take up connecting rod formed in two
parts having overlapping ends, a box shaped sleeve at the inner end of one part,
a toothed section on the top face of the inner end of the other part slidingly
engaging into the sleeve, a series of dogs on the inner face of the top of the
sleeve engaging with the toothed section, a bar, or plate, on the end sleeve engaging
beneath the dogs and means for raising said bar to simultaneously disengage all
the dogs.
6. The combination with the cylinder levers of a brake apparatus, of a tie or
fulcrum bar having a take-up joint, an adjuster rod or bar between the levers
beyond the fulcrum bar, and an adjustable loose connection between one lever and
the bar, whereby the piston travel may be adjusted to a given length.
7. The combination with two oppositely moving levers of a car brake apparatus,
of a slack take-up connecting bar therefor made in two sections a guide sleeve
at the end of one section, a toothed bar at the end of the other section fitting
snugly into the sleeve, a series of recesses in the under face of the top of the
sleeve, and a series of dogs or pawls in said recesses engaging the teeth of the
ratchet bar.
DOf Wahu1005
FRANK ROBINSON.
JAMES HALE SEWALL.
Haseltine, Lake & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicants.