Improvements in connection with Safety Bars for Switch Points on Railways.
Year: 1889

page_text: Date of Application, 16th Aug., 1889
Complete Specification Left, 10th May, 1890-Accepted, 16th Aug., 1890
PROVISIONAL. SPECIFICATION.
Improvements in connection with Safety Bars for Switch Points on
Railways.
We, JOHN PATRICK O'DONNELL and ILLIUS AUGUSTUS TIMMIS, both of 2, Great
George Street, Westminster in the County of Middlesex, Civil Engineer, do hereby
declare the nature of this invention to be as follows:-
Our Invention has reference to improvements in connection with safety bars for
the facing points of railways.
It is the usual practice, in working the plunger and safety bar by an independent
lever for locking facing switch points to make the bar perform a circular motion
through an angle of approximately 45°, that is, raise it from its lower position, say
on the right, up to the level of the rail, and then down again to the lower position,
say on the left. Briefly, the heavy bar is always being moved to plunge the switch
points. As is known in the art, the object of the safety bar is to prevent the switch
points from being reversed during the passage of a train or engine over the points,
after the signal has been given "all clear," for such movement. It is therefore only
necessary that the safety bar should be prevented from being reversed after it has
been worked, should an engine or vehicle be upon it. It is not necessary that the
safety bar should be actually worked during the process of locking the points.
The principal object in our Invention is to reduce as much as possible the weight to
be moved or actuated by the facing point lock lever. It is obvious this result is of
great consideration, more especially where return detecting rods are connected to the
plungers, as described in O'Donnell & Stevens' Specification of Letters Patent dated
September 1888 and numbered 13,002.
We propose to carry out our Invention in the following manner :-
The facing point safety bar is arranged alongside the rail, and is supported and
performs its movement through half cranks mounted in rocker castings. One of the
half cranks is mounted upon a transverse shaft, and upon the outside end of this
shaft is a longer one.
The rod from the facing point lock lever in the signal cabin is
attached to this longer arm.
On the inside of the transverse shaft (which shaft may terminate in a bearing fixed
to the other rail, or may terminate in a bearing fixed between the four-feet way) is
This arm,
mounted another arm, at approximately the same angle as the longer arm.
inside the four feet way is connected and actuates the ordinary plunger.
Alongside the outside longer arm, which is connected to the actuating rod, is a
one-toothed sector, keyed on the transverse shaft.
A pawl carried by the longer arm engages with the tooth on the sector, on the
return motion of the facing point lock lever, and should a vehicle be upon the bar the
transverse shaft cannot be revolved, the plunger cannot be withdrawn into the unlocking
position, and the longer arm cannot return normal, the facing point lock lever
remaining in the worked position.
In the normal position, the pawl is forward, beyond the tooth in the sector,―on the
top of the toothed segment, and as the facing point lock lever is moved over the
longer arm is moved, carrying the pawl, so that upon completion of the movement, it
falls, and engages with the tooth on the sector; the transverse shaft is revolved, and
the short arm in the four-feet way moving with the shaft, inserts the plunger, and
locks the switch points.
It is obvious that, with our Invention, facing switch points may be locked, and the
respective signal given "all clear," even though a train may be standing on the
safety bar.
It is also clear that our Invention is applicable. to safety bars used in conjunction

page_text: with duplex plungers, for instance, the plungers or slide bars of the "Simplex"
machine. The latter apparatus is fully described in the Specification of Letters
Patent granted to Hill, Smith, & O'Donnell, No. 2176 of 1888.
It may be desirable in some cases, to devise other means of carrying out this
principle, as for instance the arrangement above described may be arranged horizontally,
with a spring attached to the end of the pawl, to ensure its engagement on the return
motion.
COMPLETE SPECIFICATION.
Improvements in connection with Safety Bars for Switch Points on
Railways.
We, JOHN PATRICK O'DONNELL and ILLIUS AUGUSTUS TIMMIS both of 2 Great
George Street, Westminster in the County of Middlesex, Civil Engineers 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 :-
Our invention has reference to improvements in connection with safety bars for
facing points of railways. It is the usual practice to work the plunger and the
safety bar by an independent lever for locking facing switch points making the bar
perform a circular motion approximately through an angle of 90 degrees, that is
raising it from its lower position say on the right up to the level of the rail and then
down again to the lower position say on the left. Briefly the heavy bar is always
being moved.
As is known in the art the object of the safety bar is to prevent the switch points
from being reversed during the passage of a train or engine over the points after the
signal has been given "all clear." For such movement it is only therefore necessary
that the safety bar should be prevented from being reversed after it has been worked,
it is not necessary that the safety bar should be actually worked during the process of
locking the points. The principal object in our invention is to reduce as much as
possible the weight to be moved by the facing point lock lever. It is obvious this
result is of great consideration more especially where return detecting rods are
connected to the plunger as described in O'Donnell & Stevens' Specification of Letters
Patent dated September 8th 1888 and numbered 13002.
In carrying out our invention we never actually make the bar complete the usual
movement of passing through an angle of 90 degrees, but we make the bar be
operated nearly to the rail level and then to fall back again to its normal position by
its own weight. It is obvious that our invention may be applied to the form of bar
which is actuated upon bevels or friction rollers fixed in blocks on the side of the bar
as well as to the usual form of bar actuated through a half crank or rocker and
casting.
We propose to carry out our invention in the following manner. The facing point
safety bar is arranged alongside the rail as in figures and 2; an arm is mounted
upon a transverse shaft and upon the outside end of the said shaft is a second longer
arm to which is attached the facing point lock lever in the signal cabin by the usual
rod connection. The short arm (shewn inside the 4 foot way) is connected to and
actuates the bar. It is obvious that various means may be employed for actuating the
plunger, through the rocking shaft or by a separate connection from the bar. A
suitable method would be to extend the rocking shaft to the middle of the 4 foot way
and provide on it an extra arm for the purpose of actuating the plunger through a
connection between the said arm and the plunger for the purpose of locking the
switch points. For the purposes of this invention however it will be sufficient to
describe our system of actuating the bar and the advantages thereby gained. Along-
side the outside longer arm which is connected to the actuating rod is a one toothed
sector keyed on the transverse shaft. A pawl carried by the long arm engages with

page_text: a tooth on the sector on the return motion of the facing point lock lever and should a
vehicle be upon the bar the transverse shaft cannot be revolved, the plunger cannot be
withdrawn to the unlocking position and the longer arm cannot return to the
normal position, the facing point lock lever remaining in the worked position.
The pawl in the normal position is forward beyond and on the top of the toothed
sector and as the facing point lock lever is moved over, the longer arm is moved
carrying the pawl so that upon the completion of the movement it falls and engages
with the tooth on the sector.
When the signalman returns his facing point lock lever the transverse shaft is
revolved and the short arm in the 4 foot way raises the bar nearly up to the level of
the rail the pawl is freed from the sector, and the sector and shaft and bar fall to the
normal position again.
It is obvious that with our invention facing switch points may be locked and the
respective signals given all clear even though a train may be standing on the safety
bar.
It may be desirable to devise other means for carrying out this principle as for
instance the arrangement above described may be arranged horizontally with a spring
attached to the end of the pawl to insure its engagement on the return motion.
An arrangement can also be made for a crank and rod connection to lock the
points from the rod H, itself worked from the signal box.
In order that our invention may be more clearly understood and readily carried
into effect we will describe the drawings hereunto annexed. The same letters refer
to the same parts in the several figures in the drawings.
Figure 1 is a plan showing the bar alongside the rail and the position of the
transverse shaft for the purpose of working it.
Figure 2 is a side elevation of figure 1.
Figure 3 is an enlarged side view partly in section showing the arrangement of
the toothed sector the pawl and the long arm.
Figure 4 is a front view of figure 3.
Figure 5 shows the arrangement of the bevels for the easy working of the har.
It is clearly understood with reference to this figure that the bar will never be
required to work on the other side of the bevel chair but for the purpose of preserving
the standard chair we have illustrated it as in figure 5. Should it be required that
the bar be never worked beyond the required position then for this purpose we would
prefer that a chair of the section as in figure 6 be used so that M would form a stop
to insure the bar working to its correct angle. Figure 7 illustrates the usual method
of working the bar by means of a rocker casting and half crank.
A is the bar, B the short arm at the end of the transverse shaft which operates a
short rod connection and works the bar, C is the long arm mounted loosely on the
other end of the transverse shaft which is connected with the point rod H the latter
actuated by a lever from the signal box, D is the transverse shaft, E is the pawl
centred to the longer arm C at the point F, G is the toothed sector keyed to the
transverse shaft, on this sector J is the tooth, K is a rim on the top of the casting
carrying the shaft for the purpose of tilting the pawl when it has arrived beyond the
middle of the rim in order to allow the sector to be freed and the bar to fall to the
normal position again, L is the bevel on the block fixed to the bar and N is the bevel
on the chair O. On the bar working upwards on the said bevel, M acts as a stop to
prevent it working more than its required movement when the said bar is worked on
the bevel principle.
P figure 7 is the usual half crank centred to the rocker Q for the purpose of
actuating the bar..
In cases where the facing points are a long distance from their respective signals
and where it would be possible for the signalman to replace his signal to danger and
reverse the facing points, lock bar and plunger before the train arrived at the facing
points and so be able to split the train through having the power to reverse the
facing points it is obvious that our invention is applicable to an intermediate bar fixed
between the facing point lock bar and the signal to prevent the liability of the above

page_text: mentioned danger. In this case the working of the bar would be identical with that
mentioned in reference to the figures shown upon the drawings.
In the herein before described specification reference has been made to the working
of the lever from the normal position to the worked position as being the action of
locking the points, it will however be readily understood that upon certain lines of
railway the points stand normally locked therefore the above described action would
be the means of unlocking them it is obvious therefore that to suit the various cases
the bar would be required to come into operation only when the points are being
unlocked.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we wish it to be distinctly
understood that we do not claim the apparatus in the drawings with reference to any
bars except those used in connection with facing points on railways, that is to say a
facing point lock bar or facing point rear bar, but what we do claim is :-
1st. The combination of apparatus described with reference to the drawings to
enable a facing point lock lever to be operated from the normal position without
operating the facing point lock bar and of insuring that upon the return motion of the
said lever the bar is operated, substantially in the manner described.
2nd. In railway signalling the combination of apparatus to insure that the facing
point lock bar is only operated in the action of withdrawing the plunger to the
unlocked position and that the facing point lock bar is not operated in the action of
locking the points, substantially in the manner described.
Dated this 10th day of May 1890
JOHN P. O'DONNELL,
Agent for the said Applicants.