Improvements in or connected with Fog Signalling Apparatus for Railways.
Year: 1897

page_text: Date of Application, 31st Dec., 1897
Complete Specification Left, 31st Oct., 1898-Accepted, 3rd Dec., 1898
PROVISIONAL SPECIFICATION.
Improvements in or connected with Fog Signalling Apparatus for
Railways.
We, HERBERT TOMLINS, of 100, Hammersmith Road, London, W., Decorator,
and THE ELECTRIC FOG SIGNAL SYNDICATE LIMITED, of 16, Cockspur Street,
London, W., do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in the railway fog signalling apparatus
described in a previous Application for Letters Patent dated 7th day of April
1897 No. 8907.
The improvements relate, first, to the treadle mechanism and have for object
to enable the treadle to be permanently retained in the depressed position when
fog signalling is not required and yet to permit it to automatically resume its
working position by the operation of the fog signalling apparatus itself when the
latter is brought into action by electrical agency in the manner described in the
previous specification. For this purpose a self-engaging detent is adapted to
engage directly or indirectly with the treadle bar when depressed, this detent
being disengaged from the treadle by the fall of the weighted arm which operates
the cartridge-holding disc so that whenever the weighted arm is released by
electrical means as before described and permitted to come into action for the pur-
pose of operating the fog signalling mechanism it will also act on the detent
through a suitable mechanical connection and so release the treadle. This detent
will therefore come into operation every time the treadle is depressed when the
fog signalling apparatus is in work and as the depth of the wheel flanges vary
according to the wear of the wheel treads, it is necessary that the treadle should
be retained whether depressed more or less by a flange of greater or less depth.
To reduce the chattering consequent on flanges of different depths passing over the
treadle the detent is so stepped or rack toothed, or two rack toothed detents are
so combined and coupled as to be operated conjointly and present their teeth
alternately to engagement with the treadle at the various degrees of depression
corresponding to wheel flanges of different depths so that when depressed by a
deep flange it cannot rise sufficiently to be struck by a flange of less depth so long
as the detent remains in position of engagement.
The improvements relate, secondly, to a treadle bar adapted to be moved
laterally inwards of the track by the wheel flange instead of being depressed as
before this lateral motion of the treadle being transmitted by suitable connections
to the fog signalling mechanism with the same effect thereon as was produced by
the depression of the treadle.
The improvements relate, thirdly, to the breech-closing mechanism of the cart-
ridge chambers or barrels and have for object to lessen the cost of construction
and the labour of re-charging, and consists in the provision of a single breech
block for two or more pairs of cartridge chambers (the two chambers of a pair
being on the same radius as before) so that the breeches of all the chambers
covered by the same breech block may be opened at once.

page_text: The improvements relate, fourthly, to the firing mechanism and consist in pro-
viding independent firing pins for the two chambers of each pair, that is to say
the pins are not yoked together as before, and in providing independent firing
hammers one for each circle of cartridge chambers, the hammers acting either
directly on the firing pins as before or preferably through intermediate longitu-
dinally guided striking pins so as to avoid the tendency to bend the firing pins
consequent on the angular motion of the hammers. Instead of knuckle-jointing
the hammer tails as before, to permit the return of the wiper by which the
hammers are tripped the wiper is a lever pivoted to the wiper arm and normally
spring held in position to strike the tails of the hammers but free (except as here-
after described) to yield and pass the hammers in either direction without operat-
ing them. In connection with this wiper lever there is provided a bolt adapted
to be projected into the path of the wiper lever as an abutment rendering it rigid
in the one direction so as to cause it to act on and trip the hammers in passing
them on its forward motion whilst leaving it free to yield and pass them on its
return motion, this bolt being brought into, or put out of action in the same
manner as the retractible wiper described in the previous specification or it may
be brought into action by connection with the semaphore signal operating
mechanism whenever the semaphore signal is placed at langer and put out
of action when the signal is placed at line clear."
"
A further improvement consists in placing the whole of the fog signalling
mechanism above the ground level and mechanically connecting the main shaft
of the apparatus with the treadle so as to be operated therefrom through the de-
pression or the lateral motion of the treadle as the case may be.
Dotal thi. 214 day of Hahn 1907
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.
Improvements in or connected with Fog Signalling Apparatus for
Railways.
We, HERBERT TOMLINS, of 100, Hammersmith Road, London, W., Decorator,
and THE ELECTRIC FOG SIGNAL SYNDICATE LIMITED, of 16, Cockspur Street,
London, W., 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 improvements in the railway fog signalling apparatus
described in the Specification of previous Letters Patent dated 7th day of April
1897 No. 8907.
The improvements relate, first, to the treadle mechanism and have for object
first to enable the treadle to be permanently retained in the depressed position
when fog signalling is not required and yet to permit it to automatically resume
its working position by the operation of the fog signalling apparatus itself when
the latter is brought into action by electrical agency in the manner described in
the previous specification; and to reduce the "chattering" which would result
from flanges of different depths passing over the treadle when so depressed;
secondly, to a treadle bar adapted to be moved laterally inwards of the track by
the wheel flange instead of being depressed; thirdly, to the provision in the
breech-closing mechanism for the cartridge chambers or barrels, of a single breech
block for two or more pairs of cartridge chambers (the two chambers of a pair
being on the same radius) so that the breeches of all the chambers covered by the

page_text: same breech block may be opened at once, and of an independent firing pin for
each chamber of each pair; fourthly, to the provision in the firing mechanism
of an independent firing hammer for each circle of cartridge chambers, and of a
wiper for tripping the hammers, consisting of a lever pivoted to the wiper arm
and means whereby the wiper is enabled to yield and pass the hammers in either
direction without operating them or is caused to act on and trip the hammers
on its forward, motion whilst free to yield and pass them on its return motion,
the said means being controlled electrically in connection with the semaphore
signal operating mechanism. A further improvement relates to placing the whole
of the fog signalling mechanism above the ground level..
The invention will be described with reference to the accompanying drawings
wherein Figure 1 is an elevation of a vertically depressed treadle with the
mechanism for retaining it when depressed. Figure 2 is a modification of
Figure 1, for the purpose of preventing "chattering." Figure 3 is a sectional
perspective view shewing a treadle adapted to be moved laterally inwards of the
track. Figure 4 is an elevation, and Figure 5 a plan, of the fog signal apparatus
shewing the improved firing mechanism and Figure 6 shews the mechanical con-
nection between the treadle and the fog signal apparatus when the latter is above
the ground level. The same letters of reference indicate the same parts in all the
figures.
The treadle A is connected to radius links a pivoted about fixed centres. Bis
a spring-pressed detent adapted, whenever the treadle is depressed by a wheel
flange of a passing train, to become engaged with a lug a¹ on one of the links a
so as to prevent the treadle from rising again until the fog signalling apparatus
is reset for operation. The detent B is mechanically connected to the weighted
arm which operates the cartridge holding disc so that when the fog signal apparatus
is "set," i.e. put into position to be fired by the depression of the treadle, the
weighted arm falls and the detent is automatically disengaged from the lug. a¹
thus permitting the treadle to be raised by its springs A¹ to operative position.
In consequence of the wear of the wheel treads the flanges will vary in depth
and as it is necessary that the treadle shall be retained when depressed by a flange
of minimum depth, a "chattering" would be set up when flanges of greater depth
pass over the treadle. To prevent this, the detent B might be a rack having a
number of teeth with any one of which the lug a' may engage when the treadle
is depressed to a greater or less extent. With the same object the detent rack
may be duplicated, as in Figure 2, the point of engagement with the two racks
being so alternated as to virtually halve the pitch of the teeth without reducing
their strength. The two detent racks B1, B3, are pivoted face to face on fixed
centres and coupled at opposite sides of their centres by a link 62 whereby they are
moved in opposite directions simultaneously, one of the racks being in mechanical
connection with the fog signalling apparatus as before. A link a pivoted to the
link a, is adapted to engage by a cross head a³ with one or other of the detent
racks B1, B2, according to the extent to which the treadle is depressed.
Referring to Figure 3, C is the laterally movable treadle laying along the inner
side of the rail the treadle being adapted to slide on a shoe 1) fixed to the rail or
to the sleeper, when the flange of a wheel comes between the treadle and the rail.
The treadle C is connected by a rod passing through or beneath the rail, to a
lever I counterweighted or spring pressed so as to maintain the treadle close
to the rail, the lever being fixed on a shaft connected by any mechanical means
with the main shaft of the signal firing mechanism.
The fourth improvement is shewn in Figure 4 and consists in making the
breech block E broad enough to cover two or more adjacent pairs of breech
chambers, each block being hinged so as to swing inwards towards the centre of
the disc when opened and each being locked when in the closed position in the same
manner as described in the previous patent aforesaid and each being provided
with independent firing pins e, one for each chamber. In combination therewith
we employ two independent hammers F F', mounted in position to act respectively

page_text: on the firing pins of the two circles of chambers. The hammer heads are carried
by spring shanks mounted on the same elbow lever f pivoted at fl to a fixed
bracket and pressed by a spring f in the direction of the stroke of the hammer
to an extent limited by a stop so that the hammer heads will deliver their
blows independently although carried by the same elbow lever, and will rebound
and stand normally in a position to allow the firing pins to pass clear of them
when the disc is revolved. The means for tripping the hammers and causing
them to deliver their blow, consists of a wiper lever g pivoted at g on a centre
carried by the wiper arm G fast on the treadle operated rock shaft H, as before,
the wiper lever being normally held by a spring in position to strike the tail
of the hammer lever but free to yield and pass in either direction without operai-
ing them except when it is held rigid in one direction by a bolt i mounted to slide
longitudinally in guides in the wiper arm G and which when released is projected
into the path of the wiper lever g by a spring so as to cause the wiper lever to
trip the hammers on its forward motion. In order to prevent the bolt i, when set
free, rising on the wrong side of the wiper lever g the latter carries a quadrant
plate which sweeps over and obstructs the path of the bolt i when, the bolt i
being retracted, the lever g is oscillated by coming in contact with the tail of
the firing hammer. The bolt is held retracted and inoperative when the line
is clear, by a latch lever pivoted at to the wiper arm G and caused by a spring
to engage in a notch in the bolt i when the bolt is retracted by the action of an
electro-magnet K mounted on the wiper arm. The disengagement of the latch j
is effected by an electro-magnet L through a connection of the latch lever j with
the armature of said electro-magnet, which is carried by a stationary support,
the electro-magnet K being energized when the semaphore signal is lowered to
"line clear" and the electro-magnet L being energized when the signal is raised
to line blocked."
Figure 6 illustrates the arrangement of the apparatus above the ground level.
In this case the treadle A, carried by a pair of radius links as before and pressed
upwards by springs, acts on a lever arm m fast on a shaft M passing beneath the
rails and having another arm m fast on it which engages by a link, pin and slot,
or equivalent connection with a lever arm N on the rock shaft Fl of the cartridge
holding disc, the construction and arrangement of the mechanism being otherwise
the same as above described.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is:-
1. In fog signalling apparatus such as herein referred to the combination with
the treadle and with the weighted arm by which the cartridge holding disc is
operated, of means of retaining the treadle depressed until the fog signalling
apparatus is reset for operation as described.
2. In fog signalling apparatus such as herein referred to the combination with
the treadle and with the weighted arm by which the cartridge holding disc 's
operated, of means of retaining the treadle depressed in the lowest position to
which it can be moved by the deepest wheel flange so as to prevent chattering"
under wheel flanges of different depths substantially as specified.
3. The combination with fog signalling apparatus such as herein referred to
of a treadle adapted to be moved laterally by the wheel flange coming between t
and the rail instead of being depressed for operating the fog signalling mechanism
substantially as specified.
4. In fog signalling apparatus such as herein referred to the combination with
the cartridge holding disc having pairs of cartridge chambers arranged in con-
centric circles as described, of breech closing blocks hinged as described and
adapted to close two or more pairs of cartridge chambers and having independent
firing pins for each chamber as described.
5. In fog signalling apparatus such as herein referred to the combination with

page_text: the cartridge holding disc having pairs of cartridge chambers arranged in con-
centric circles as described, of independent spring-shank hammers for each circle
of firing pins and of wiper mechanism for tripping the hammers, said wiper
mechanism being constructed and adapted to operate substantially as herein
.specified.
6. The combination of the fog signalling mechanism herein referred to when
arranged above the ground level, with a treadle operated rock shaft coupled to
the rock shaft of the fog signalling mechanism for operation thereby substantially
as specified.
Dated this 31st day of October 1898.
A. M. & WM. CLARK,
Chartered Patent Agents, 53, Chancery Lane, London.