Improvements in Fog Signalling Apparatus for Railways.
Year: 1895

page_text: Date of Application, 17th May, 1895-Accepted, 22nd June, 1895
COMPLETE SPECIFICATION.
Improvements in Fog Signalling Apparatus for Railways.
I, JOHN GEORGE DIXON, of "Ivy House," Lindley, Huddersfield, in the
County of York, 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 :-
My invention has reference to improvements in fog signalling apparatus on
railways.
"
The fog signals or detonators now generally used are placed on the rails by
fogmen, to indicate to drivers the locality of a signal and whether in the "Danger
position. If a fog signal has been placed on the line and the condition of the line
is changed so that the section ahead has become clear, the signal being drawn to the
Safety" attitude, the fogmen are accustomed to withdraw the detonator from
the rail placing it on again for the next "Danger" signal.
66
The risk is considerable, and the object of my invention is to arrange that each
train in passing a signal or a given spot where detonators are desired to be used,
explodes the detonator and resets my machine, placing another detonator on the
line for the next train. If the signal is lowered to the "Safety" attitude the
detonator is withdrawn from the line.
In order that my said invention may be better understood and more readily
carried into effect I will describe the drawings hereunto annexed :-
Figure 1 (Sheet 1) is a plan on top of the dash-pot or cylinder and the connected
parts.
Figure 2 is a sectional elevation through the dash-pot or cylinder, piston, and
treadle.
Figure 3 is a front elevation of the dash-pot casting, showing the method of
putting the apparatus in gear and out of gear.
Figure 4 is a side elevation of Figure 1.
Figure 5 is a plan of the magazine and connected parts with the cover removed.
Figure 6 is a sectional elevation on line X-Y Figure 5.
Figure 7 is a side view of Figure 5.
Figure 8 is a sectional side view on line A-B Figure 5, showing the jaws or clip
in the magazine ready to move the detonator on to the rail.
Figure 9 is a modification of the mechanism for opening the jaws, allowing the
spent detonator to fall and also enabling the jaws to clip a fresh detonator. The
cam in this figure through which the jaws are opened is at the left hand corner of
the box farthest from the rail.
Figure 10 is a section on line V-W, Figure 9.
Figure 11 is a further modification for opening the jaws to allow the spent
detonator to be dropped and a new one brought on to the rail.
The same numbers refer to the same parts in the several figures of the drawings.
1 is the treadle or bar fixed parallel to the rail, fulcrumed at 2; 3 is the trans-
verse lever attached to the bar 1, fulcrumed at 4 and connected at 5 to a red 6
the latter working the dash-pot or cylinder 7. 8 is the piston; 9 is the piston rod
fastened at its lower end 10 to the outer case 12; 13 is a hole to allow of the
escape of water and prevent it getting into the cylinder; 14 is a leather valve;
15, 15, are the valve holes for the escape of air; 16 is the lower lever attached to
the outer case and 17 the upper lever for keeping the transverse lever 3 in the

page_text: raised position so that the detonator is off the rail and the machine out of use;
18 is the lip or projection which, coming in contact with the lower side 19 of the
bracket on the casting, prevents 16 from falling or being moved to the right; 20 is
the centre connecting 16 and 17 together. The lower part of 17 is rounded and
the upper part of 16 is also formed to receive the lower part of 17 so that when the
wire is pulled to the left both 16 and 17 are moved with it, the upper part of 17
assuming a lower level (as in Fig. 4) allowing the transverse bar or lever 3 to fall
raising the bar 1 and putting the machine into gear; 21 is a locking rod attached
to a projection 22 on the transverse lever 3; the rod 21 works through a guide 23
and when the signal lever in the cabin is pulled over, wire or chain 29 is slackened
and crank 25 falls by gravity, and the train on passing over the treadle bar moves
21 forward ou to a lower projection 24 on the crank 25 preventing the crank 25
from moving to allow the detonator 47 to go back on to the rail. 26 is a piece
fixed on the upper side of the transverse lever 3 projecting over the lower arm of
the crank 25 in the position shown in Figure 4. 27 is an additional weight on the
transverse lever 3, but such weight may be dispensed with if the cylinder is made
an equivalent increased weight, the cylinder acting as a counter-balance to the
treadle 1. 28 is the rocking shaft upon which the transverse lever is fixed; 29 is
a wire connecting the crank 25 to the T lever 30; 31 is the balance weight on
lever 30 32 is a pawl on lever 30 prevented by a stop 33 from being moved
downwards, but the said pawl may move upwards. The lever 30 is keyed to a
shaft 34 on the other end of which shaft is an arm or lever projecting downwards
and terminating in teeth forming a rack 35; in gear with this rack is a pinion 36, the
pinion is also fastened to a vertical shaft 37. Keyed to the upper part of the shaft
is the lower jaw 38 and centred to the lower jaw is the upper jaw 39; centred to a
projection on the lower jaw (Fig. 6) is a small lever 40 terminating in a friction
roller 41 a projection 42 from the upper jaw passes through a hole in the lower
jaw. A balance lever and weight 43 is centred to a projection 44 from the lower
jaw and it rests upon the upper jaw at point 45, keeping the jaws tight together for
gripping the detonator clip; 46 is the detonator clip and 47 the detonator. 48 is a
cam upon which the roller 41 moves when the jaws are moved away from the rail
towards the magazine; 49 is the lowered part beyond the cam to which the friction
roller may
fail closing the jaws when the latter have arrived opposite the detonators
so as to get a firm grip for moving the next detonator on to the rail. 50 is a flap
centred to the top of the case containing the mechanism of the magazine, which
cannot be moved into the magazine and therefore offers an obstruction knocking
out the spent detonator from the jaws; the jaws are free to move into the magazine
but the extra length caused by the detonator and clip finds an obstruction in the
flap and by that means the spent detonator is knocked out. On the jaws coming
out of the magazine with a new detonator the flap is raised, being capable of
moving outwards, and falls back again when the jaws and detonator bave passed
free towards the rail. 51 is a lever attached to the signal wire operating the signal
to which the detonator is intended to refer; its balance weight is 52.
The arm 53
is intended to come in contact with the pawl 32 to move the balance lever 30
thereby communicating motion to the jaws and detonator.
The working of my invention is as follows:-
In the normal position, assuming the semaphore signal to be at "Danger," a
detonator will be on top of the rail, as shown in Fig. 5, and the treadle bar will be
raised, as shown in Figs. 1 to 4. The train in moving towards the machine travels
over the detonator first, explodes it and depresses the treadle; this action raises
the other end of the transverse lever 3 and cylinder 7. The raising of the trans-
verse lever frees the lower arm of the crank 25 by the projecting piece 26 being
moved upwards; by freeing the crank 25 the balance lever 30 draws the wire 29
connected to lever 25 moving the latter lever and raising the lower arm;
lever 30 being moved through its balance weight the shaft 34 is turned and
through the downward projecting arm 35 being geared to the pinion 36, the pinion
is revolved, the upright vertical shaft 37 is also revolved and in their turn the jaws
on

page_text: and spent detonator are moved to the right (Plan Fig. 8), into the magazine; in
passing the flap 50 the spent detonator is discharged but previously the jaws have
been opened by the friction roller 41 thrusting upwards the projection 42 attached
to the upper jaw 39. When the spent detonator has been discharged by the flap 50
the friction roller 41 has fallen to the lower level 49, the new detonator is between
the jaws, the dropping of 41 on to 49 closes the jaws, and when the last wheel has
passed over the treadle bar 1 the air in the cylinder escapes through the valve
holes 15; the cylinder acting as a balance weight lowers the transverse lever, raises
the treadle, brings the projecting piece 26 over the lower arm of the crank 25, forces
the lower arm downwards, tightens the chain or wire 29, brings the lever 30 into
its normal position shown in Fig. 7, the lever 30 going through the previously
described movement of operating 35, that in its turn moving the pinion 36, the
latter, through the shaft, moving the jaws and detonator onto the rails, as shown
in Fig. 5 ready for the next train. All these movements it will be noted have
been independent of the signalman the signal remaining at "Danger" the whole
time.
"
The machine when the signal is kept in the "Danger" attitude for a succession
of trains is perfectly automatic, one train setting the machine and putting a
detonator on the rail for the next succeeding train. If, however the signalman
wishes to lower his semaphore arm to the "Safety" attitude, it is well understood
that the detonator should also be removed from the rail, otherwise there would be
contradiction of signals. As the lever 51 is attached to the wire operating the
semaphore arm, the signalman in working the semaphore arm to the "Safety"
attitude, moves lever 51, lever 51 in turn through its arm 53 operates lever 30 in
the opposite direction to that previously described, that is to say, the weight is
moved upwards and the shaft 34, pinion 36, vertical shaft 37, jaws and detonator
are all moved the latter to the left, away from the rail, so that the fog signal is in
conformity with the semaphore arm. After the passage of the train, on the
signalman replacing the signal to the "Danger" attitude, the machine goes through
a similar return operation and the detonator is placed on the rail in the position
shown in Fig. 5. In order, however, to prevent the signalman from putting his
lever back and the signal to "Danger "before the train has passed clear of the
treadle bar, by which action he would put a detonator on the rail when it was not
required, when the signalman pulled over his operating lever in the cabin moving
the lever 51, it in its turn moved lever 30 and slackened wire 29 and crank 25 fell
by gravity; now when the train passes over the treadle bar 1 and operates the
transverse lever 3, the locking rod 21 is moved above. and to obstruct the passage
of the projection 24 on the lower side of the crank 25. By this action the return
of the crank 25 to the normal position, as shown in Fig. 4 is prevented, consequently
the jaws and detonator cannot return to the normal position and the detonator
itself cannot be placed on the rail, being held to the left hand worked off position
by the locking rod 21 locking the crank 25.
The advantage of the piston and cylinder used in this application is well known,
as the principle has been described in my former Specification of Letters Patent
No. 9545 of A.D. 1893. The modification in this instance is that the piston is a
fixture to the bottom of an outer case, the piston being capable of oscillation with
the cylinder, the cylinder acting as a counter-balance weight.
My present invention consists generally in improvements on the invention
described in the Specification of Letters Patent granted to me, No. 95.15
of A.D. 1893 hereinbefore referred to.
As hereinbefore stated Figures 9, 10 and 11 are modifications of the mechanisın
for opening the jaws of my machine.
In Figure 10, 42 is an L piece projecting down from the balance lever through
the top jaw, and 40ª is the equivalent of 40 in Figure 6, being placed at the end
of the balance lever instead of projecting from the lower jaw 33. The friction
roller 41 in moving up the cam 40* raises the balance lever 43 and the piece 42
raises the upper jaw 39.

page_text: The modification in Figure 11 different from Figure 6 is that the downward
projection 42 from the upper jaw is used to support the lever 10 and the friction
roller 41 instead of having a separate bracket depending from the lower jaw. The
straight surface 42ª in 42, on 41 moving up the cam, prevents 40 from further
revolving and forces up the upper jaw.
In my prior Specification of Letters Patent above cited there were illustrated a
feeding arm and upper and lower jaws and a counter-balance lever operated by the
signal lever in the cabin. There were also illustrated springs in connection with
the magazine and feeding mechanism. In my present invention I have abolished
such springs and substituted weights.
I wish it to be distinctly understood that I claim nothing described or claimed
in my former Specification of Letters Patent No. 9545 of A.D. 1893 above
referred to.
lt
Although the description and illustrations herein show an automatic fog signal
apparatus, yet if desirable the feeding jaw mechanism and magazine might be used
without the treadle bar and its connections. In this application the detonator
would follow the movement of the semaphore arm to which it applied. It would
be normally on the line when the signal is at "Danger" and would be drawn off
the line to the magazine when the signal is lowered to the "Safety" attitude.
is obvious, however, that it would be necessary to either work the signal for every
train or to work a separate lever interlocked with the signal lever so that the
special fog signal lever would release the signal lever for every forward movement
of the latter moving the semaphore arm to the "Safety" attitude, but would be
specially interlocked, in the well known manner in the profession, so that the fog
signal lever could not be left normally over, that is to say normally worked, so that
the signal lever could be operated any number of times without the fog signal
lever being worked. For every time the signal is placed to "Danger" a detonator
would have to be previously placed on the line.
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. An automatic fog signal apparatus operating that the passage of each train
over a treadle sets a detonator on the rail behind it ready for the next train, all
substantially as set forth and as illustrated in the accompanying drawings.
2. An automatic fog signal apparatus the detonator jaws and detonator of which
are capable of being moved out of contact with a passing train when the signal to
which it applies and is connected is moved to the "Safety attitude, all
substantially as set forth and as illustrated in the accompanying drawings.
"
3. In a fog signal machine, jaws controlled by balance weight for gripping the
detonator holder, the upper jaw and balance weight being moved to free the
detonator holder through a friction roller and lever the former moving along a cam,
substantially as described and illustrated in the accompanying drawings.
4. The combination of the weight controlled jaw and the connected mechanism
for raising the latter, the rack and pinion mechanism and balance lever operating
the latter and the treadle bar and dash-pot and connected parts, all substantially as
set forth, for the purposes specified and as illustrated in the accompanying
drawings.
5. The combination of the weight controlled jaw and the connected mechanism
for raising the latter, the rack and pinion mechanism and balance levers one
operating the latter and the other being operated by the signal lever for the
purposes of placing a detonator on the line and withdrawing the same therefrom,
substantially as herein described.
6. A treadle bar operating through a transverse lever, an inverted cylinder the
latter moving about a piston fulcrumed at its lower end, the cylinder and piston
being incased in a suitable case, substantially as herein described and as illustrated
in the accompanying drawings.

page_text: 7. Apparatus consisting of links for placing in gear and out of gear a treadle
bar, substantially as described and illustrated with reference to Figures 1 to 1 of
the drawings annexed.
Deted this 17th day of May 1895
JOHN P. O'DONNELL Fei. Chart. Inst. P.A.,
70 & 71 Palace Chambers, Westminster, S.W.,
Agent for the said Applicant.