An Improvement in Interlocking Apparatus for Railway Point and Signal Levers.
Year: 1889

page_text: Date of Application, 15th Mar., 1889
Complete Specification Left, 9th Dec., 1889-Accepted, 1st Feb., 1890
PROVISIONAL SPECIFICATION.
An Improvement in Interlocking Apparatus for Railway Point and
Signal Levers.
We, JOHN STINSON FARMER of Canterbury Road, Kilburn in the County of
Middlesex, Engineer and HUGH REID of No. 6 Pilrig Cottages, Leith Walk in the
County of Edinburgh, Signal Fitter, do hereby declare the nature of this invention
to be as follows:-
In many interlocking apparatus for railway point and signal levers, sliding bars or
plungers moved by the levers are crossed by other bars having on them projections
or tappets which engage in notches of the plungers locking them, or are disengaged
therefrom unlocking them, or which are themselves unlocked or locked according as
they find or do not find notches in the plungers which they can enter. This invention
relates to interlocking apparatus of this character, so modified that all locking and
unlocking are effected by the spring catches of the levers acting in conjunction with
the levers themselves. The object that we have in view is to effect all necessary lock-
ing by the raising of a spring catch of a lever before the lever itself is moved, and to
prevent any unlocking from being effected until a lever, moved to the end of its stroke,
is secured there by the descent of its spring catch. For this purpose, we connect to
each lever a plunger in the form of a sliding plate, and on this plate we mount by. hori-
zontal radial arms a parallel motion bar which is connected to the spring catch of the
lever in such a manner that when the spring catch is raised this bar is caused to move
in a direction parallel to that of the plate. As the bar in making its travel along the
plate is guided in a circular are by the radial arms,, it is compelled to move also
laterally and by this movement it causes some of the tappet bars to slide transversely;
or comes to a position where it obstructs their movement, these bars effecting the
necessary locking that should he done before the operating lever is moved. The lever
then being moved, the plunger plate which moves with it, if it does not present
notches to receive tappets when it is in its new position, does not unlock any levers
which are effected by those tappots, notwithstanding that the lowering of the spring
catch withdraws the parallel motion bar from the tappets on which it had acted, By
extending the radial arms beyond their pivots and linking to them a second parallel
motion bar, this bar is by the movement of the spring catch made to operate on tappets
in the same manner but in the opposite direction. By thus giving movement to the
tappet bars, the objectionable friction and wear attending the mode' usually' adopted
for moving them by inclined faces are obviated.
1 10'00'
ABEL & IMRAY,.,
Agents for the Applicants.
COMPLETE SPECIFICATION.
An Improvement in Interlocking Apparatus for Railway Point and
Signal Levers.
603
We, JOHN STINSON FARMER of Canterbury Road, Kilburn in the County of
Middlesex, Engineer and HUGH REID of No. 6 Pilrig Cottages, Leith Walk in the
County of Edinburgh, Signal Fitter 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:-
17
L.
In many interlocking apparatus for railway point and signal levers, sliding bars
or plungers moved by the levers are crossed by other bars having on them projections
or tappets which engage in notches of the plungers locking them, or are disengaged

page_text: therefrom unlocking them, or which are themselves unlocked or locked according as
they find or do not find notches in the plungers which they can enter. This invention
relates to interlocking apparatus of this character, so modified that all locking and
unlocking are effected by the spring catebes of the levers acting in conjunction with
the levers themselves.
The object that we have in view is to effect all necessary locking by the raising of a
spring catch of a lever before the lever itself is moved and to prevent any unlocking
from being effected until a lever moved to the end of its stroke, is secured there by the
descent of its spring catch. For this purpose, we connect to each lever a plunger in
the form of a sliding plate, and on this plate we mount by horizontal radial arms a
parallel motion bar which is connected to the spring catch of the lever in such a
manner that when the spring catch is raised this bar is caused to move in a direction
parallel to that of the plate. As the bar in making its travel along the plate is guided
in a circular arc by the radial arms, it is compelled to move also laterally and by this
movement it causes some of the tappet bars to slide transversely; or comes to a posi-
tion where it obstructs their movement, these bars effecting the necessary locking that
should be done before the operating lever is moved. The lever then being moved, the
plunger plate which moves with it, if it does not present notches to receive tappets
when it is in its new position does not unlock any levers which are affected by those
tappets, notwithstanding that the lowering of the spring catch withdraws the parallel
motion bar from the tappets on which it had acted. By extending the radial arms
beyond their pivots and linking to them a second parallel motion bar, this bar is by
the movement of the spring catch made to operate on tappets in the same manner but
in the opposite direction.
By thus giving movement to the tappet bars, the objectionable friction and wear
attending the mode usually adopted for moving them by inclined faces are obviated.
Fig. 1 of the accompanying drawings is a side view of part of a point or signal
lever Land its spring catch rod S with their connections to the locking gear shewn
in plan by Figures 2, 3, 4 and 5.
The lever is linked to a sliding plate or plunger P which moves to and fro with
the lever. The spring catch rod S is jointed to one arm of a bell crank lever B the other
arm of which is linked to a rod R which can slide to and fro and also transversely on
the plate P, the jointing of the link A connecting it to the bell crank B being such
as to allow of a little lateral motion of the rod R.
As will be seen on the plans, on each plate P are pivotted two radial arms D jointed
to the rod R and also to a parallel rod C.
As the joint pins of these arms D move in circular ares, whenever the rod R is
moved longitudinally along the plate P it must also move a little outwards and cause
the rod C also to move outwards. Under the plates P there are arranged a number
of transversely sliding bars having fixed on them at suitable places tappets T pro-
jecting up from them to the level of the upper surfaces of the rods R and C. The
plates or plungers P have in their edges notches N in suitable places to receive some
or others of the tappets T which act for interlocking the plungers.
When the plungers that are to be interlocked are adjacent to one another, the
tappets T are merely short slides; when the interlocking plungers are some distance
apart, the tappets T T are separate pieces fixed on a bar which can slide under the
intermediate plungers. The operation of the interlocking gear may be best understood
by tracing the action of one of the levers L and its spring catch on the plunger and
parallel bars in the various positions marked c¹² in Figures 2, 3, 4 and 5.
In the position the lever L being at one end of its stroke and its spring catch
rod S being down, the plunger P is locked by a tappet Tin a notch at the one edge of P
and also by a tappet T¹ in a notch at the other edge, but both these tappets are free
to be moved aside because there is a notch facing T in the edge of the adjacent plunger
and there is a notch facing T2 which is fixed on the same bar with T. The operator can
therefore raise the spring catch of the lever and by doing so without moving the
lever itself the parallel rods R and C to the position a³, whereby the tappets T and T¹
are thrust out of the notches of P, T being by this movement thrust into the notch of the

page_text: a
adjacent plunger, and T2 being also thrust into a notch. So far this movement has
locked two plungers that were previously free, and has not unlocked any plungers.
The lever L being now moved to the other extreme of its stroke, the parts are in the
position, no unlocking being yet effected. On now letting down the spring catch
of the lever, the parts take the position x, in which position the locking
previously effected by the raising of the spring catch is maintained, but
notch N in the edge of P being now presented towards a tappet T³, that tappet
is free to be thrust into the notch and consequently the lever now locked by it can be
unlocked by the raising of the spring catch of that lever. In a similar manner lock-
ing and unlocking are effected by the upward and downward movements respectively
of other spring catches of the set of levers; and, obviously the notches of the
plungers and the tappets for entering them may be arranged to suit the particular
conditions of interlocking to which the set of levers should be subjected.
Sometimes the notching of a plunger is required on only one of its edges; in such a
case the parallel rod C may be dispensed with.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed we declare that what wo
claim is :-
In interlocking apparatus for railway point and signal levers, in combination with
each lever and its spring catch rod, is notched plunger linked to the lever, a bell crank
pivotted on the lever and connected to the spring catch, a rod linked to the bell crank
and jointed to radial arms pivotted on the plunger, and tappets sliding transversely to
the plunger substantially as and for the purpose herein set forth.
Dated this 9th day of December 1889.
ABEL & INRAY,
Agents for the Applicants.