Improvements in Railway Signals.
Year: 1892

page_text: Date of Application, 2nd Feb., 1892-Accepted, 16th Apr 1892
COMPLETE SPECIFICATION.
[Communicated from abroad by THE FONTAINE SAFETY SIGNAL COMPANY,
of the City of Detroit, in the County of Wayne and State of Michigan,
United States of America.]
Improvements in Railway Signals.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co., Patent
Agents, 45 Southampton Buildings, in the County of Middlesex, 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 :-
The invention applies to that class of railway signals, the object of which is to
prevent two trains from following each other too closely, by automatically
indicating to the succeeding train the time elapsed since the preceding train has
passed the signal, up to a certain number of minutes considered as ample time
allowance between two trains to be out of dangerous proximity.
Siguals of this character comprise two kinds of actuating mechanism, the object
of which is to merely derive a certain force or impulse from the movement of the
train in passing the signal and secondary or transmitting mechanism for utilizing
said impulse to operate the index hand of a clock dial to indicate the time elapsed
up to a certain number of minutes, since the primary force or impulse has been
received, i.e. since the train has passed.
This invention consists in the improved construction of such secondary or
transmitting mechanism, and its peculiar combination with a primary actuating
mechanism, as hereinafter described.
Figure 1 is a diagram elevation partly in section of a railway time signal
embodying the improvement.
Figure 2 is a vertical section at right angles to Figure 1.
Figure 3 is a detached and enlarged rear elevation of the clockwork forming a
part of the secondary actuating mechanisni.
Figure 4 is a side elevation of Figure 3.
Figure 5 is a top plan thereof.
Figure 6 is an elevation of the friction clutch forming a part of the clockwork.
Figure 7 is a section on lineæ in Figure 4.
Figure 8 is a detail of construction of parts indicated by letters of reference and
more specifically referred to hereinafter.
Figure 9 is an enlarged central section of the lifting rod S.
Figure 10 is an enlarged horizontal section of the connection C¹ and wrist W.
A A represents the two track rails and B represents the primary actuating
device of the signal which may be of suitable description, whereby the wheels of
the locomotive or cars in passing over a prescribed spot in the track impart a pull
to a connecting bar, chain or cable C, such devices being well known to the state
of the art for operating switches or signals of all kinds and forming no part of the
present invention.
For the purpose, however, of explaining the operation of the signal more fully,
there is shown in Figure 1 a simple illustration of such a device, in which D is a
lever fulcrumed near one rail and having a short end projecting into the path of
the wheels of a passing train, while the long end is connected with a dash pot E,
and with the cable C through the medium of a spring arm F.
The wheels of a train in passing will depress the short end of the lever, and the
dash pot will prevent the lever from being actuated more than once by a train in
passing, while the spring arm F prevents the cable C from being pulled too
violently.

page_text: The secondary or transmitting devices of the signal are constructed as
follows:-
G is a hollow mast constructed preferably of cast iron or tubing in two sections,
the upper section supporting on top of the signal proper, and the lower section
provided with a base plate G', and at a distance above ground convenient for
easy access, with an enlargement or box G² into the top of which the upper section
is secured.
The top of this post is detachably secured to the frame G³, provided with two
segmental discs G, one in full view to a train approaching in one direction and the
other to a train approaching in the opposite direction, and as a time allowance of
about twenty minutes is accounted ample to bring two trains succeeding each other
out of dangerous proximity, the dial is preferably limited to indicate that number
of minutes more or less according to the distance the signals are placed apart.
These discs are inscribed with large figures and indicated by division marks to be
plainly seen and easily read at a distance.
Below the dials, recesses (³ are formed in the two opposite faces of the
frame G³ in which the minute hands H are inclosed to be protected from atmo-
spheric disturbances.
These minute hands are radially secured to bevel pinions H on opposite sides of
a central bevel pinion H2 with which both are engaged to communicate motion in
opposite directions to the minute hands, and weights H³ are secured to the minute
hands on their actuating bevel pinions to counterbalance the weight of the minute
hands.
The minute hands and their actuating bevel pinions are mounted upon a base Go
upon which the frame G³ is adjustably secured and forms a protecting casing over
the enclosed parts. The base G is detachably secured upon the top of the post
and forms a tight cover to exclude moisture from the interior of the mast, it also
has a raised central bearing G' for the bevel pinion H2 through which bearing the
vertical shaft to which said bevel pinion is secured projects centrally down into
the mast.
This shaft is constructed in three sections J, J, J2; the upper section J has a
squared end engaging loosely into a corresponding socket formed in the section J¹
and the upper end of the lower section J2 engages with the middle section J' by
means of a tension joint with a coil spring J³, the tension of which is adjusted to
convey the motion in one direction as will appear more fully hereinafter. This
joint as constructed in the drawings consists of a pintle J, and a corresponding
step J formed on the engaging ends of the sections J J' respectively, the step is
partly cut away at its lower end, and a pin J is secured on the pintle adapted to
engage with the cut-away portion of the step.
The coil spring J³ is secured at one end to the clamping collar Jo and at the
other end to the clamping collar J, which are respectively clamped upon the
shaft sections J, J. To the lower end of the section J' the bevel pinion J' is
secured and meshes with a bevel pinion J8 on the main shaft K of a clock
mechanism.
This clock mechanism is inclosed in the box G2 which is suitably constructed
to protect it from atmospheric disturbances and from being maliciously tampered
with.
The clock mechanism is mounted upon a suitable frame detachably secured
within the box and having the main shaft K suitably journalled thereto.
The clock mechanism may be of any suitable description adapted to revolve the
shaft K at a suitable rate of speed for imparting the prescribed movement to the
minute hand of the dial through the connections described, preferably however
constructed as follows:-
A suitable clock spring L is secured upon the shaft K in the usual manner to
cause said shaft to revolve under the control of an escapement. This consists of
the screw gear wheel M mounted upon the shaft K, the screw M' on the vertical
shaft M' engaging with said gear wheel, the escape wheel M³ mounted on the upper

page_text: end of the shaft M³, the escape lever M₁ having the pallets M³ engaging with the
escape wheel, having its fulcrum at Ms the arm M pivotally secured at M³, and
carrying the pivot M of the escape lever, the adjoining screw nuts M' and the
screw M for adjustably holding the free end of the arm M', the segmental
rack M" formed on the free end of the escape lever M the horizontal balance
wheel M¹ mounted on a shaft M18 and the pinion M on the shaft M¹³ engaging
with the segmental rack M".
The pitch of the screw M' is made sufficient to transmit a small amount of
pressure from the spring to the pallets of the escape lever so as to produce in the
escapement the well known pulsative movement of a watch or clock escapement
which in like manner controls the unwinding of the spring and thereby causes the
shaft K to revolve in a proper ratio of speed required for the minute hand of the
dial.
By means of the adjusting nuts M the pallets of the escape lever may be caused
to engage more or less deeply into the escape wheel and thereby afford means to
make the pulsations shorter or longer to regulate the movements to keep proper
time. If desired however the balance wheel may be provided with the usual
balance spring, the adjustment of which as in ordinary time movements is made
use of to regulate the movement to keep proper time. This construction however
is considered preferable for the purpose.
The screw gear wheel is revolved by the shaft K, through the medium of a
clutch which is preferably constructed as shown in Figure 6, and in which N is an
annular hub secured to or formed on the screw gear wheel M; within this is fitted
a loose friction ring N¹ which is severed at one point to form a small opening N²
into which the wedge shaped end of a dog N³ engages. The dog N³ is hinged to
the member N which is fast upon the shaft K and is adapted to engage on a
stud N on the friction ring.
By this construction it will be seen that if the shaft K revolves in the direction
of the arrow in Figure 6, as it does by the unwinding of the spring, the dog N³ is
wedged into the opening N2 forcing the ends of the ring apart and causes the
friction ring to become fast in the annular hub N by frictional contact, whereas
when the shaft revolves in opposite direction as in winding the spring the dog will
sufficiently withdraw from the opening N2 to allow the ring to become loose within
the hub and be carried freely around by the engagement of the fast member N¹ on
the stud N. By a partial severing of the ring diametrically opposite to the
severed place N' the ring will readily expand and contract, when the wedge shaped
end of the dog is forced up into or withdrawn from between the severed ends of
the friction ring. To keep it engaged within the hub, guards No are detachably
secured to the gear wheel M.
O is a gear wheel or segment of a gear wheel secured upon the shaft K and
engaging with a vertical rack bar P slidingly secured in a longitudinal slot of the
vertical guide post G. This post is preferably made round and is adjustably
secured in a vertical bearing Qformed on the clock frame; its lower portion is
provided with a vertical slot Q2 which registers with the guide slot in which the
rack bar is inclosed and its upper end is cut away sufficiently towards the side of
the gear wheel O to prevent its interfering with the free engagement of the gear
wheel and rack bar.
Below the clock mechanism is pivotally secured at one end the lifting lever R,
the free end of which projects loosely into the slot Q2 of the guide post underneath
the rack bar P. S is a lifting rod pivotally secured at its upper end to the lever B
and at its lower end to one arm of a bell crank lever T.
The lifting rod is made adjustable in length, preferably as shown in the drawing
wherein it supports at its upper end a screw threaded extension piece S¹ loosely
engaging in a socket formed therein, and by means of adjusting nuts upon the
extension piece, the normal position of the lifting lever R is adjusted vertically.
The bell crank lever T is enclosed in a housing U which is secured to the under

page_text: side of the flanged foot of the mast in a space provided between two sleepers
upon which the mast is supported.
'
The bell crank lever is pivotally secured between the walls on the top of the
housing and its downwardly projecting arm is provided with a wrist W pivotally
connected thereto. To this wrist one end of the cable C is secured through the
medium of a suitable connection C₁ so that the slack in the cable may be taken up
when required. A suitable stop Z may be placed behind the bell crank to hold it
in normal position.
The cable is enclosed in a pipe W₁ one end of which is secured to the housing U,
and the other end to a housing Y which encloses the primary actuating device.
In practice, the parts being constructed and arranged as shown and described,
the device is intended to operate as follows:
The pull imparted to the cable C through the primary actuating device by the
wheels of a locomotive or train of cars which in passing must depress the inner
end of the lever D, is directly transmitted through the cable to the bell crank T
and through the connecting rod S to the lever R. The lever R in its upward
movement pushes up the rack bar P and thereby causes the gear wheel to revolve
and wind up the spring the necessary amount for making the clockwork go the
twenty minutes more or less for which it has to operate. During such winding
the clutch will disconnect the shaft K from the escapement. Simultaneously upon
the winding of the spring the bevel gear wheel J, revolving with the shaft K imparts
motion to the bevel gear wheel shaft J2 J J and bevel gear wheel H2 H'H',
thereby causing the minute hands H to be set from their advanced position
to zero.
When the parts are actuated in this manner the spring J³ transmits by its
tension the motion from the shaft section J2 to the section J at least to the limit
of the loose joint, and thus the motion is eased and no breakage or damage to the
parts can result. As the spring L on the shaft K resists with its power the turning
of the shaft it will have the effect of a buffer spring to prevent destructive results
from the impulse which when derived from the wheels of a fast going train
naturally must be more or less in the nature of a blow.
As the primary actuating device returns to its normal position as soon as the
train has passed, the lever R will simultaneously drop back and the spring L
becomes free to react. This throws the clutch mechanism immediately into gear
and the unwinding of the spring can now take place under the control of the
escapement, which, being constructed to produce the required ratio of speed, will
impart the proper travel to the minute hands. It will be observed that as the
shaft K is now revolved in an opposite direction the two sections J J2 are now in
positive engagement with each other and no lost motion can take place.
While the hands are advancing on the dials, the rack bar P will gradually
drop back and when the hands indicate 20 minutes, further movement will be
stopped by the impingement of the lower end of the rack bar against the lever R,
or it may be stopped if desired by the action of any other suitable stop in the
mechanism, such as by a stop O' on the gear wheel O striking against the
frame.
If another train passes the signal before the full time indication, the operation is
the same as before, that is, the minute hands will be set back to zero and then
resume their travel. It is obvious that in such a case the rack P not having fully
dropped back to its normal position the spring will only be wound the amount it
has lost, so no overwinding can take place.
It is obvious that instead of a clock spring, a suitable weight may be used,
also instead of two hands and dials, but one hand and dial may be used. It is
evident however, that in the latter arrangement it would have to face parallel to
the track, else it would be restricted to indicate only for trains going one way.
It will be seen that this clock mechanism differs from other clock mechanism in
that the time indication is derived directly from the winding shaft, so that the

page_text: winding also carries the hand back to an initial position. Furthermore this action
is entirely accomplished by the mechanical transmission of the initial impulse from
the passage of the train.
It has been found that only by positive mechanical transmission beginning at the
rail and continuing throughout the entire mechanism to the index hand, is it
possible to insure reliable indication but the difficulty is to carry this out so that it
will make no difference whether the signal receives its positive impulse from a
slow going freight train or from an express moving perhaps at a rate of sixty miles
an hour, the impulse from which is almost instantaneous and liable to destroy any
mechanism devised for indicating time.
This difficulty is overcome by making the connection between the shaft K of the
clock mechanism and the minute-hands in such a manner that while this connection
is absolutely positive when indicating the time it is flexible when it transmits the
direct impulse which sets the hands to zero, the various details of construction
have also their peculiar advantages in this respect, thus the peculiar_arrange-
ment and combination of the cable, bell crank, connecting rods S, lever R, rack P
and gear wheel O and shaft K precludes the presence of any lost motion when the
device is in its normal position and it positively opposes the power or pressure of
the spring to the impulse it will receive from the primary actuating device. This
is supplemented by the action of the weight of some of these parts which all assist
to prevent any destructive results from a violent pull transmitted by a fast moving
train.
The out door conditions under which the signal has to operate make it also
imperative to safely protect all the mechanism from climatic influences as well as
against malicious tampering and afford at the same time ready access to examine
and adjust if necessary any part which need be.
This protection is afforded by my construction and ample provisions are made
for readily adjusting any part without dismounting the signal, the connections
between the primary device and the shaft K cannot be affected injuriously by any
variations of temperature and the sliding connection between the shafts J and .j¹
takes up all the expansion or contraction in the other parts liable to be
affected.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed as communicated to me by
my foreign correspondent, I declare that what I claim is :-
1. In a railway time signal, the combination with a primary actuating device
operated by a passing train, of transmitting mechanism comprising a clock work
with dial indication, a positive mechanical connection between the winding shaft of
said clock mechanism and the primary actuating device and between the said
winding shaft and the indicating hand on the dial, for winding the clock mechanism
and setting the indicating hand by the direct transmission of the initial impulse
from a passing train, substantially as described.
2. The combination with the primary actuating device of a railway signal, of
indicating clock mechanism having its winding shaft connected to said primary
device for winding it by a direct impulse therefrom, and having a dial indication,
the index band of which is moved in either direction by intermediate connection
with the winding shaft, said intermediate connection being arranged to operate the
hand positively by the movement of the clock mechanism and yieldingly in the
opposite direction, substantially as described.
3. The combination with the clock mechanism for operating the index hand of
the dial, of the gear wheel O on the winding shaft of said clock mechanism, the
rack bar P secured in vertical guide bearings, the lifting lever R adapted
to operate said rack bar, the lifting bar S, the bell crank lever T having one arm
connected to said bar, and the cable C connecting the other arm of said bell crank
with the primary device, substantially as described.
4. The combination with the clock mechanism for operating the index hand of

page_text: the dial, of the gear wheel O on the winding shaft of said clock mechanism, the
rack bar Pengaging therewith, the vertical guide Q in which said rack bar is
guided, the lifting lever R engaging into a vertical slot of the guide Q to operate
said rack bar, the vertical lifting bar S adapted to lift said lever, having the
extension S¹ adjustably supported thereon, having one arm connected to said bar,
the cable C connecting the other arm of said bell crank lever with the actuating
primary device of the signal, and a device for adjusting the length of said cable,
substantially as described.
5. The combination with the actuating clock mechanism of the signal, of the
gear wheel O secured upon the winding shaft of said clock mechanism, the vertical
rack bar P engaging with said gear wheel, the vertical adjustable post Q provided
with a vertical groove in which said rack bar is held the lifting lever R guided in
a vertical slot in the post, the adjustably jointed lifting bar S actuating the
lifting lever, the bell crank lever T having one end connected to the connecting
bar, the wrist W pivotally secured to the bell crank lever, and the cable C and
screw threaded coupling link C¹ adjustably connecting said wrist with the primary
actuating device of the signal, substantially as described.
6. In a railway time signal, a clock mechanisin adapted to operate the index
hand of a dial in either direction by the movement of the winding shaft through a
direct connection between the index hand and said winding shaft, said connection
being adapted to rigidly connect the two in the movement of unwinding and
yieldingly connect the two in the movement of winding, substantially as described.
7. In a railway time signal, a clock mechanism adapted to operate the index
hand of a dial in either direction by the movement of the winding shaft through
intermediate gearing between the index hand and said winding shaft, said gearing
having a flexible shaft connection consisting of the shaft sections JJ, a lost
motion connection between the same and a tension spring J³ connecting the two
shaft sections to take up the lost motion between the same in one direction and
form a limited flexible connection in the opposite direction of the movement of
said shaft substantially as described.
Dated this 2nd day of February 1892.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.