signal apparatus
Year: 1896

page_text: Date of Application, 19th Feb., 1896
2000
2000
I, JOHN GEORGE DIXON, of "Don Villa," Penistone, in the County of York,
Engineer, do hereby declare the nature of this invention to be as follows:-
-
My invention has reference to improvements in fog signalling apparatus for
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 or whether in the "Danger
position.
The absence of a fog signal is supposed to indicate the safety of the line.
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.
The risk is considerable and it frequently happens that, instead of the detonator
being withdrawn from the rail when the danger signal has been lowered to the
"Safety" attitude, fogmen leave the detonators on the rail and 'an explosion
takes place. So far, therefore, from the driver getting any accurate information
as to the condition of the signal he is positively misled, for by the explosion of
a detonator he is supposed to be informed that the signal is at "Danger" and
that, therefore, he should stop, whereas, the signal having been lowered to the
"Safety" attitude he should proceed; he, therefore, stops when he ought not to
stop, thereby rendering a collision from the rear liable, for the signalman can
allow a second train to come into the section on the supposition that the first has
proceeded in consequence of his lowering the danger signal to the "Safety'
attitude.
"
"
My invention is, therefore, to endeavour to make the detonator follow the
movement of the signal arm, so that when a signal arm is lowered to the "Safety'
attitude the detonator will be withdrawn from the rail.
My present invention consists in improvements on the invention set forth in the
Specification of Letters Patent granted to me, No. 9808, dated May 17th 1895,
and refers more particularly to an improved construction of the jaws for gripping
the detonator holder, an improved form of the mechanism for operating the jaws
while the latter are moving to and from the magazine and rail, and again, to an
improvement by which if the wheels are braked and therefore skid, the detonator
shall not be pushed from the line without being exploded when it ought to be
exploded.
There are further improvements which however are merely constructional and
need not be described here.
In the first mentioned improvement in connection with the jaws, I arrange that
the lower jaw is a fixture and made part and parcel of the upright shaft, the pinion
is also part of the shaft, the whole being preferably made of cast steel. The upper
jaw is normally loose and fits into a slot in the lower jaw, a pin rest being provided
in the lower jaw acting as a fulcrum. An upward projection is formed in the upper
jaw. To the sides of the lower jaw uprights are provided and pinned to these is a
counter-balance lever projecting beyond the upright shaft. In the normal condition
of the jaws, that is to say, when across the rail, the counter-balance lever is down

page_text: and is pressing on the projection on the upper jaw raising the weighted end of the
latter and depressing the jaw end, keeping the upper and lower jaws tightly
together. When a detonator is removed from the rail the end of the counter-
balance lever operates on a cam, the counter-balance lever is raised and the weighted
end of the upper jaw falls by gravity so that the jaw is opened.
My improvement in the cam mechanism is as follows:-
The cam is fulcrumed to the side of the case of the machine and is supported by
projection from the rack. In the normal position the cam slants from the highest
position, farthest from the pinion shaft, to a lower level nearer the pinion shaft.
The action is that when the lever connected to the treadle bar is operated and the
rack, also connected to the same lever, is moved, the pinion is operated by the rack,
the jaws and spent detonator are removed from the rail towards the magazine.
During this action the pin projection at the end of the balance lever above the top
jaw is moved towards the cam and as soon as the pin arrives at the cam at the same
time the side projection from the rack is moving the end of the cam upwards, raising
the counter-balance on the top jaw, opens the jaw (the spent detonator falling out)
and by the time the jaws have arrived at the magazine and in position to grip the
next detonator holder, the pin projection at the end of the counter-balance lever
above the top jaw has got free of the cam and dropped. By this action the jaws
are closed and another detonator gripped.
On the return stroke of the jaws and detonator out of the magazine towards the
rail the pin projection at the end of the counter-balance above the top jaw rides
underneath the cam and raises it and when the detonator is normal and across the
rail is free of the cam again in the normal position.
My third improvement consists in providing a stop upon the lever attached to the
signal wire for bringing the detonator from the rail into a safety position when
the signal is lowered to the "Safety" attitude, and also a corresponding stop upon
the lever attached to the treadle bar which moves the jaws to the magazine for
recharging, the whole acting that if a wheel does not revolve and a skidding action
ensues both weights and both levers have to be moved before the detonator can be
moved clear of the rail, the counter-balance lever and weight attached to. the
sigual arm having to be moved first before the counter-balance lever which operates
the detonator can be moved and therefore before the detonator can be moved away
from the rail.
I wish to lay no claim to any of the parts described in my former Specification
of Letters Patent No. 9808 of 1895.
'JOHN P. O'DONNELL, Fel. Chart. Inst. P.A.,
70 & 71 Palace Chambers, Westminster, S. W., .
Agent for the said Applicant.
I, JOHN GEORGE DIXON, of Don Villa, Penistoue, in the County of Yorks,
Engineer, do hereby declare the nature of this invention and the manner in which
the same is to be performed, are particularly described and ascertained in and by
the following statement :-
My invention has reference to improvements in fog signalling apparatus for
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 or whether in the "Danger".
position.

page_text: The absence of a fog signal or detonator is supposed to indicate the safety of
the line.
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.
This risk is considerable and it frequently happens that, instead of the detonator
being withdrawn from the rail when the danger signal has been lowered to the
"Safety" attitude, fogmen leave the detonators on the rail and an explosion takes
place. So far, therefore from the driver getting any accurate information as to the
condition of the signal he is positively misled, for by the explosion of a detonator
he is supposed to be informed that the signal is at "Danger" and that, therefore,
he should stop, whereas, the signal having been lowered to the "Safety
attitude he should proceed; he therefore stops when he ought not to stop, thereby
rendering a collision from the rear liable, for the signalman can allow a second
train to come into the section on the supposition that the first has proceeded in
consequence of his lowering the danger signal to the "Safety" attitude.
With my invention I arrange that the detonator follows the movement of the
signal arm, so that when a signal arm is moved to the safety attitude the detonator
will be withdrawn from the rail.
My present invention consists in improvements on the invention set forth in the
Specification of Letters Patent granted to me, No. 9808, dated May 17th 1895,
and refers firstly to an improved construction of the jaws for gripping the detonator
holder. Secondly an improved form of the mechanism for operating the jaws while
the latter are moving to and from the magazine and rail, and thirdly, to an improve-
ment by which if the wheels of a train are braked and therefore skid, the detonator
shall not be pushed from the line without being exploded when it ought to be.
exploded.
There are further improvements which are however merely constructional and
need not be described here.
In the first mentioned improvement in connection with the jaws, I arrange that
the lower jaw is a fixture and made part and parcel of the upright shaft, the
pinion is also part of the shaft, the whole being preferably made of cast steel. The
upper jaw is normally loose and fits into a slot in the lower jaw, a pin rest being
provided in the lower jaw acting as a fulcrum. An upward projection is formed on
the upper jaw. To the sides of the lower jaw uprights are provided and pinned or
pivoted to these is a counter-balance lever having a pin in its weighted end
projecting beyond the upright shaft. In the normal condition of the jaws, that is
to say, when across the rail, the counter-balance lever is down and is pressing on
the projection on the upper jaw raising the weighted end of the latter and depressing
the jaw end, keeping the upper and lower jaws tightly together. When a detonator
is removed from the rail the end of the counter-balance lever operates on a cam,
the counter-balance lever is raised and the weighted end of the upper jaw falls by
gravity so that the jaw is opened.
My improvements in the cam mechanism is as follows:-
The cam is fulcrumed to the side of the case of the machine and is supported
by a projection from the downwardly projecting arm or lever having the rack at its
lower end, as set forth in my above cited Specification No. 9808 of 1895. In the
normal position the cam slants from the highest position, farthest from the pinion
shaft, to the lower level nearer the pinion shaft.
My third improvement consists in providing a stop upon the lever attached to the
signal wire for bringing the detonator from the rail into a safety position, when the
signal is lowered to the "Safety" attitude, and also a corresponding stop upon
the lever attached to the treadle bar which moves the jaws to the magazine for
recharging, so that if a wheel does not revolve and a skidding action ensues both
weights and both levers have to be moved before the detonator can be moved clear
of the rail instead of only one as in my above cited specification.

page_text: In order that my invention may be better understood and more readily carried
into effect I will describe it with reference to the accompanying drawings, in
which
Figure 1 is a plan 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 side elevation of Figure 1.
Figure 4 is a plan of the magazine and connected parts with the cover removed,
showing my present improvements.
Figure 5 is a cross sectional elevation on line A-B of Figure 4.
Figure 6 is a side view of Figure 4.
Figure 7 is a sectional side view on line C-D of Figure 4 showing in dotted
lines my improved jaw mechanism or detonator gripper in the magazine ready to
move the detonator on to the rail.
Figure 8 is a side elevation of my improved jaw mechanism or detonator gripper
in the closed position.
Figure 9 is a side elevation partly in section of my improved jaw mechanism,
showing the jaws in the open or operated position.
Figure 10 is a plan of the jaw mechanism.
Figure 11 is a general view showing the relative positions of the dash-pot and
treadle bar and the magazine and the wire connection between' the same, and the
wire connection to the operating lever in the signal cabin.
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
transverse lever attached to the bar 1, fulcrumed at 4 and connected at 5 to the
rod 6 the latter working the dash-pot or cylinder 7. 8 (Fig. 2) is the piston; 9 is
the piston rod swivelled 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 the
leather valve, and 15 are the valves 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 raised position when it is desired that the machine should remain out of
working, keeping the bar 1 below the level of the rail. 18 (Fig. 3), is the lip or
projection on the end of the lever 16, which, coming in contact with the lower
side 19 of the bracket on the easing, 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 from
the vertical position keeping the transverse lever 3 raised as shown in dotted lines
in Figure 2, the upper part of 17 assuming a lower level (as in Figure 3) allowing
the transverse bar or lever 3 to fall thereby raising the treadle bar 1 and putting
the machine into gear. 21 is the locking rod attached to the projection 22 on the
transverse lever 3; the rod 21 works through the 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 on to a
lower projection 24 on the crank 25 preventing the crank 25 from moving to allow
the detonator 55 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 Figures 1, 2 and 3. 27 is an additional weight on the transverse
lever 3, but such weight may be dispensed with if the cylinder 7 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 3 is fixed; 29 is
the wire connecting the crank 25 to the T lever 30 (Fig. 11). 30 & 51 are
respectively the stops on levers 30 and 51, forming my third mentioned improve-
ment, stop 30 normally bearing on stop 51. 31 is the balance weight on lever 30;
32 is the pawl on lever 30 prevented by stop 33 from being moved downwards, but
said pawl may move upwards. The lever 30 is keyed to shaft 34 on the other end

page_text: of which shaft 34 is the arm or lever 35 projecting downwards and terminating in
teeth forming a rack 36, a projection 37 being provided (according to my present
improvements) at the top of said arm 35; 38 is the pinion at the lower end of
shaft 38 which latter is formed in one piece with the lower jaw 41, said pinion
gearing with the rack 36. 39 is my improved form of cam, centred to the case
at 40 for operating the detonator jaws or gripping mechanism as hereinafter
described; this cam normally rests on the projection 37.
Referring to Figures 8, 9 & 10 which are enlarged views illustrating my
improved detonator gripping mechanism 41 is the lower jaw made in one piece
with the shaft 38 at the lower end of which shaft is formed the pinion 38 as above
mentioned; 43 is a pin fixed approximately about the middle of the jaw 41 and
upon said pin loosely rests the upper jaw 44 which is weighted at its end 45; 46 is
the counter-balance lever pivoted to the projections 47 on the lower jaw 41. The
upper jaw 44 works in a slot 48 in the lower jaw 41, and up in the upper jaw 44 is
formed the slight projection 49 on which the counter-balance lever 46 bears.
the end of the counter-balance lever 46 is a pin or projection 50.
At
51 (Figures 4, 5, 6 and 11) is the weighted lever attached to the signal wire
operating the signal to which the detonator is intended to refer, its balance weight
being 52; the arm 53 is intended to come in contact with the pawl 32, to move the
balance lever 30 when the operating lever in the signal cabin is pulled, thereby
communicating motion to the jaws and detonator. 54 is the detonator clip and
55 the detonator.
The working of the above described invention comprising my present improve-
ments 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 Figures 4 and 5, and the treadle bar 1 will
be raised as shown in Figures 1, 2 and 3. 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 with it the cylinder 7.
The raising of the transverse 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 crank 25 moving the said crank and
raising its lower arm; on lever 30 being moved to the right through its balance
weight 31, the pawl 32 rides free of the arm 53 on crank 51 and gets upon said
arm. This allows the signalman to pull off bis semaphore arm, to which semaphore
arm crank 51 is attached by wire 56, to get rid of the train without effecting the
lever 30 or other portion of the magazine mechanism. Through this movement of
the lever 30, the shaft 34 (Figures 4, 5 and 6,) is turned and through the down-.
wardly projecting arm or lever 35 being geared by its rack 36 to the pinion 38, the-
vertical shaft 38 is also revolved and in their turn the jaws and spent detonator
are moved to the right (plan Figure 4), towards the magazine; and during a
portion of this movement the spent detonator is discharged from the jaws, the jaws
having been opened in the following manner-Referring to Figures 4, 5, 7, 8
and 9, when the lever 30 is operated as above described the projection 37 on the
downwardly projecting arun or lever 35 is lowered and the cam 39 resting on said
projection is also lowered; simultaneously with this movement the pinion 38 is
operated by the rack 36, the shaft 38* is turned and the detonator gripping jaws 41
and 44 are moved to the right towards the magazine. During this movement
towards the magazine the pin 50 at the end of the counter-balance lever 46
connected to the upper jaw 44 rides over an inclined surface of the cam 39, thereby
raising the counter-balance lever 46 free of the projection 49 upon the upper loose
jaw 44 allowing said jaw by means of its weighted end 45 to open; the jaws having
moved into the magazine are in position to grip a new detonator, and upon the
pin 50 now dropping over the edge 39 of the cam 39 the counter-balauce lever 46
drops, and again bearing on the projection 49 (Fig. 9) closes down the upper jaw 44
and the detonator is gripped. When the new detonator has been gripped as above
described, and the last wheel of the train has passed over the treadle bar 1, the air

page_text: in the cylinder 7 escapes through the valve holes 15; the cylinder 7 acting as a
balance weight lowers the transverse lever 3, raises the treadle 1, brings the
projecting piece 26 to bear on the lower arm of the crank 25, forces the lower arm
downwards pulling the wire 29 and bringing the lever 30 into its normal position
shown in Figure 4, the lever 30 going through the previously described movement
of operating 35, that through its rack 36 moving the pinion 38, the latter through
shaft 38 moving the detonator on to the rail, as shown in Figure 4, ready for the
next train. On this return movement of the jaws and detonator out of the
magazine towards the rail, the pin projection 50 at the end of the counterbalance
lever 46 rides underneath the cam 39 and raises it and when the detonator is
normal and across the rail as in Figures 4 & 5 the pin 50 is free of the cam again
and in the normal position. 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 bis 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 56, operating the
semaphore arm, the signalman in working the semaphore arm to the "Safety
attitude, moves lever 51 to the left, lever 51 in turn through its arm 53 coming in
contact with pawl-32 operates lever 30 in the opposite direction to that previously
described, that is to say, the weight 31 is moved upwards and the shaft 34, vertical
shaft 38 with its pinion 38, 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 replaced on the rail in the position shown in Figure 4. 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 is not required, when the signalman
pulled over his operating lever in the cabin, moving the lever 51 which in its turn
moved lever 30 and slackened wire 29, 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 Figure 3 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.
With reference to my third mentioned improvement for preventing the
detonator being pushed off the rail by the skidding of a wheel, the action is as
follows:-
In my former invention as set forth in my above cited Specification No. 9808
of A.D. 1895, there was only the weight 31 on the lever 30 to keep the detonator
from being skidded off the rail in the event of the wheels of the train being
braked. With my present invention I arrange that the additional weight 52 on
the lever 51 is brought to bear on the lever 30 by means of the stop 51" bearing
on the stop 30 on lever 30, so that if there was any tendency to force the detonator
gripper towards the left, off the rail, the additional weight 52 on the lever 51 would
have to be overcome.
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 mechanical fog signalling machines for railways improved means for

page_text: operating the jaw which grips the detonator, substantially as herein described with
reference to Figures 4 to 9, inclusive of the drawings annexed.
2. In mechanical fog signalling machines for railways, additional means for
ensuring that the detonator keeps its proper position on the rail should the wheels
of a train be braked avoiding the tendency to push the detonator away from the
rail without explosion, substantially as herein described with reference to Fig. 4 of
the drawings annexed.
Dated this 19th day of November 1896.
JOHN P. O'DONNELL, Fel. Chart. Inst. P.A.,
70 & 71 Palace Chambers, Westminster, S.W.,
Agent for the said Applicant.