Improvements in Fog Signalling Apparatus for Railways.
Year: 1892

page_text: Date of Application, 15th Mar., 1892
Complete Specification Left, 15th Dec., 1892-Accepted, 4th Mar., 1893
PROVISIONAL SPECIFICATION.
Improvements in Fog Signalling Apparatus for Railways.
1, LEICESTER BRADNEY STEVENS of Darlington Works, Southwark Bridge
Road, in the County of Surrey, Engineer do hereby declare the nature of this
invention to be as follows:-
1
This invention for improvements in fog signalling apparatus for railways has for
its object to provide means or apparatus to be actuated automatically by the wheels
of a passing train so as to operate an audible signal such as a gong or, to sound a
whistle, fog horn, or the like.
In an apparatus constructed according to this invention a pedal lever is placed
outside one of the rails near a signal, and is so situated that the passage of the
wheels of a train depresses one end and causes it to operate a hammer to strike a
gong, or to operate a whistle or fog-horn, or to actuate any other form of audible
signal. The said pedal lever is connected to a treadle bar placed at a suitable
distance in front of it and beside the rail, so that, when one or more wheels have
passed over the foot of the pedal lever they ride over the treadle bar which is made
long enough to span the distance between any two successive wheels in the train,
and thus the pedal foot is held free of the passing wheels and further repetitions of
the signals presented so long as the wheels are passing over the treadle bar, the
number of signals sounded by the passage of the train depending on the distance
apart of the said pedal lever and treadle bar.
When the signal is at "danger" the pedal foot and treadle bar are in an
operative position ready to be depressed by a passing train; but in the lowering of
the signal to "line clear" they are depressed into an inoperative position free of
the passing wheels by a suitable cam actuated by the signal lever, the act
of lowering the signal being indicated by the sounding of a second signal. When
desirable I disconnect the fog-signalling apparatus from the ordinary signal lever
and actuate it by means of a separate lever, windlass or other suitable device; and
two or more of such fog signalling apparatus may be coupled together and
operated from one centre independently of, or in conjunction with the ordinary
signal levers.
It will be obvious that this optional mode of working may be effected, either
entirely by mechanical means or by a combination of suitable mechanical and
electrical devices.
Dated this 15th day of March 1892.
WHEATLEY & MACKENZIE,
40, Chancery Lane, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Fog Signalling Apparatus for Railways.
I LEICESTER BRADNEY STEVENS, of Darlington Works, Southwark Bridge
Road, in the County of Surrey, Engineer, 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 for improvements in fog signalling apparatus for railways has for
its object to provide means or apparatus to be actuated automatically by the wheels
of a passing train so as to operate an audible signal, such as a gong, or to sound a
whistle, fog horn or the like; and consists of a treadle lever placed on the side of
one rail and connected to a gong hammer, and to a long treadle bar in advance
Pin1

page_text: of it, so that the wheels of a train passing over the treadle bar depresses it, and
causes the said hammer to strike the gong, while the depression of the treadle bar
in advance prevents the two frequent depression of the treadle lever by holding it
down beyond the reach of the wheels during the passage of the remainder of the
train, the passage of a train being indicated by an electric indicator, in the signal
box, controlled by the treadle bar or other part of the gong mechanism.
In the accompanying two sheets of drawings:
Figure 1 represents a perspective view of an apparatus constructed according to
this invention, a part of the treadle bar being removed, and
Figure 2 illustrates the arrangement of electrical indicator for indicating to the
signalman whether the treadle bar is free from a train or not.
A treadle lever a, placed outside the rail b, is connected through the shaft c,
lever d, and crank e, to the gong hammer f which at each depression of the treadle
lever a by the wheel of a passing train, is caused to strike the gong g.
The treadle lever a is also connected through the shaft c, lever h, rod i, bell
crank lever 1, rol m, and lever n with the shaft o of the balanced rocking treadle
bar p, so that the depression of the lever a causes the depression of the bar p. The
length of the treadle bar p is sufficient to span at least the distance between any
two wheels of a train. It will be seen that after a train has passed the lever a and
reached the bar the said lever and bar are both held down by the passing wheels
until the last wheel of the train has left the treadle bar, thus preventing the
further depression of the lever a. By suitably adjusting the distance between the
lever a and the bar p the lever a may be depressed one or more times during
the passage of a train, and the gong g sounded on each depression.
When the signal is set at "danger" the treadle lever a and treadle bar p are
elevated into their normal and operative positions, by the counterweight 9 and
levers e and hammer f, ready to be depressed by a passing train, but on the lowering
of the signal to "line clear" they are depressed into inoperative positions free of
the passing wheels by a suitable cam bar working in guides & and being connected
to the signal lever by a connecting wire t, the cam u engaging with the roller v and
displacing the lever wand with it the lever a and bar p through their connections,
all as clearly shown. On the return of the signal lever from the "danger" to
"line clear" position the cam bar r is returned to its normal position by the
weighted lever which permits the treadle lever and bar to resume their normal
and operative positions also. The gong y may be replaced by a fog horn or whistle
connected to an air or steam reservoir and controlled by a lock or valve connected
to the pedal lever a.
As the fog signalling apparatus may not be within the sight of the signalman,
especially in foggy weather, or may not be in working order, it is necessary that
some means within the signal box should be provided to indicate whether or not a
train has passed over the treadle bar or lever, and whether the apparatus is in
proper working order. For this purpose the electric indicating or detecting
apparatus shown in Figure 2 is provided, in which an indicating arm y is rigidly
mounted on an arbor a pivotted in suitable sockets (not shown) and partially
counterbalanced by the weighted arm aa.
Arranged beneath the balance weight 9 of the treadle bar p is an electric contact
key, the lever ab of which, when no train is on the bar, and the apparatus is in
working order, is depressed by the counterweight q and closes the electric circuit ac
to energize the electromagnet ad which attracts its armature ae, causing the
hammer af to strike the gong ag to attract the signalman's attention, and the
arm ah to engage with the weighted arm aa, and rotate the indicating arm y from
the position indicated in dotted lines to the elevated position shown. The contact
key ab may be repeated at different moving parts of the mechanism to indicate any
derangement or breakdown of those parts, such for example as treadle lever a or
weighted lever x. On the depression of the treadle lever or arm by the wheels of
a train the weight q and contact lever al are raised, and the electric circuit broken,
when the armature ae falls away from the poles of the magnet ad and allows the

page_text: arm y to fall into the position shown in dotted lines, thereby indicating to the
signalman the passage of a train over the apparatus. Should the apparatus from
any cause become deranged or broken, so that the bar por other working part
engaging with the detector contact lever ab fails to recover its normal position
after the passage of a train, the electric circuit will remain broken, and the
army occupying the position shown in dotted lines will then indicate such derange-
ment to the signalman.
If desirable an electromagnetic lock of any well known construction may be used
in conjunction with the indicating or detecting apparatus, and be controlled by the
same electric circuit as will be readily understood.
It will be obvious that the electric indicating or detecting apparatus hereinbefore
described is applicable for detecting the position of any treadle bar when used
apart from the audible part of the apparatus.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. In fog signalling apparatus for railways: The combination of a treadle lever
displaced by the wheels of a passing train to operate the striking mechanism of an
audible signal, with a treadle bar for holding the said lever beyond the reach of
the wheels of the passing train substantially as described and for the purposes
specified.
2. The combination of a treadle lever and a treadle bar so connected together
that the force of impact is directly resisted by the said lever which is afterwards
held out of reach of the passing wheels by the treadle.
3. In fog signalling apparatus for railways; moving the treadle lever and treadle
bar into inoperative positions when the line is clear by means of a sliding cam
operated by the signal lever substantially as described.
4. The combination of the various parts constituting my improved fog signalling
apparatus, the whole arranged constructed and operating substantially as described
in the foregoing Specification and illustrated in the drawings hereunto annexed.
Dated this 15th December 1892.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.