An Improved Method of and Apparatus for Interlocking Railway Point and Signal Levers.
Year: 1888

page_text: Date of Application, 25th Jan., 1888
Complete Specification Left, 27th Sept., 1888
Complete Specification Accepted, 2nd Nov., 1888
PROVISIONAL SPECIFICATION.
An Improved Method of and Apparatus for Interlocking Railway
Point and Signal Levers.
We, JOHN SAXBY and JOHN STINSON FARMER both of Canterbury Road, Kilburn
in the County of Middlesex, Engineers and ARTHUR J. GRINLING, District Engineer,
Great Northern Railway and GEORGE Fox, Signal Inspector, Great Northern Railway,
both of No. 32 Friar Gate, Derby in the County of Derby do hereby declare the
nature of this invention to be as follows:-
In many lever frames for working railway points and signals, the interlocking of
the levers is effected by the movement or obstruction or sliding rods which being
linked to the levers move with them if they are free, or placing obstructions to others
of the rods or prevent the levers from moving if they themselves are obstructed by
the agency of others of the sliding rods of the set. This invention relates to the
actuation of these sliding rods in such a manner that each rod effects all necessary
locking before the lever to which it belongs is moved at all, and cannot effect any
unlocking until its lever is moved fully over and held at the end of its stroke. For
this purpose the sliding rod is not linked to the lever but is attached to a slide at the
side of the lever, this slide presenting in its upper and in its lower edges a notch or
gab. The spring catch of the lever is linked to the middle nearly horizontal arm of a
three armed lever which is pivotted on the main lever, and which has its two other
arms nearly vertical the one extending upwards the other downwards, each arm having
a pin which can engage in a gab of the slide above mentioned, the one in gab of its
upper edge and the other in the gab of its lower edge. These gabs are so situated
relatively to the circular paths in which the pins of the three armed lever move that
the action is as follows
When the spring catch is raised out of the quadrant notch which holds a lever at
either end of its stroke, it moves the three armed lever causing the slide and sliding
rod to move a little. The lever is then moved over moving the slide and sliding rod
with it and causing one of the pins of the three armed lever to be withdrawn from
one of the gabs and the other pin to be engaged in the other gab of the slide. When
[ Prica Sa

page_text: it reaches the end of its stroke the spring catch is let down into the quadrant notch to
hold the lever. This descent of the spring catch again moves the three armed lever,
and its pins again acting in the gabs of the slide move the slide and sliding rod a little
farther onwards. Thus for each movement of a lever the movement of its sliding rod
is divided into three portions, a first portion effected by the raising of the spring
catch and effecting all necessary locking of others of the levers before the main lever
is moved at all; a second portion accompanying the main lever in its stroke and main-
taining all the locking effected by the first portion; and a third or final portion
effected by the descent of the spring catch to hold the moved over lever and then,
and not till then, is any unlocking effected such as is consistent with the altered
position of the lever. By thus making the first and the last portions of the movement
of the sliding rod result respectively from the ascent and the descent of the spring
catch of a lever, it is rendered certain that all necessary locking is effected before the
lever is moved, and that no unlocking is effecting until after the lever has been moved
fully over and fixed in its altered position.
Daind this 24th day of January 1888

page_text: COMPLETE SPECIFICATION.
An Improved Method of and Apparatus for Interlocking Railway
Point and Signal Levers.
We, JOHN SAXBY and JOHN STINSON FARMER both of Canterbury Road Kilburn
in the County of Middlesex Engineers, and ARTHUR J. GRINLING District Engineer
Great Northern Railway and GEORGE Fox Signal Inspector Great Northern Railway,
both of No. 32 Friar Gate Derby in the County of Derby 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 :-
In many lever frames for working railway points and signals, the interlocking of
the levers is effected by what is known as plunger and tappet apparatus, or similar
mechanism in which plungers or sliding rods linked to the levers move with them if
they are free and place obstructions to others of the rods, or if they are themselves
obstructed by agency of others of the rods, they prevent the levers to which they are
linked from being moved. This invention relates to the actuation of these sliding
rods in such a manner that each rod effects all necessary locking before the lever to
which it belongs is moved at all, and cannot effect any unlocking until its lever is
move fully over and held at the end of its stroke.
For this purpose, the sliding rod or plunger is not, as usual, linked to the lever but
is connected to it through a slide which is worked partly by the lever and partly by
the spring catch of the lever, as illustrated by the accompanying drawings. Fig. 1 is
a transverse section of a lever frame shewing one of the signal levers A, its spring
catch B and the quadrant with its shoulders against which the spring catch engages
to hold the lever at each end of its stroke. Fig. 2 is a back view of the frame partly
in section. Fig. 3 is a plan of the sliding rods or plungers and tappets for their inter-
locking. Fig. 4 is a part side view to an enlarged scale shewing the connection of the
slide to the lever and its spring catch. Each of the sliding rods or plungers D) is
jointed to a slide E at the side of the lever A, this slide presenting notches or
gabs ele at its upper and lower edges. The spring catch B is linked to the middle
of a lever F which is pivotted on A and has pins ff projecting from its upper and
lower arms. When the spring catch B is raised to release the lever A, the pin f,
moving in a circular path to escape from the gabe, causes the slide E to move a little
to the right and thus move the plunger D a corresponding distance. The lever A is
then moved over, taking with it the slide E and plunger D and engaging the pin f
in the gab e². When the lever A reaches the end of its stroke the spring catch D is
let down and the pin f2 in escaping from the gab e moves the slide E and plunger D
a little farther to the right. Thus, for each movement of a lever A, the movement of
its plunger D is made by three steps, the first step caused by the raising of the spring
catch B effecting all necessary locking of others of the levers before the lever A is
moved at all, the second step accompanying A in its stroke and maintaining all the
locking effected by the first step and the third or final step caused by the descent

page_text: of the spring catch B and it is then, but not till then, that the movement of D is
sufficient to effect such unlocking as is consistent with the altered position of the
lever A. By thus making the first and the last portions of the movement of the
plunger result respectively from the ascent and the descent of the spring catch, it is
rendered certain that all necessary locking is effected before a lever is moved, and that
no unlocking is effected till after the lever is moved fully over and secured by the
spring catch in its altered position. The plungers D, as shewn in Fig. 3, have in
their edges inclined notches in which engage the oblique edged tappets G fixed on
transverse sliding levers H. When one of the plungers such as D2 presents a notch
to receive a tappet G2 on the transverse bar H then the plunger D1 can be moved
thrusting out of its notch the tappet G¹ and thus thrusting G2 into the notch of D2,
and so locking the lever to which D2 belongs. If however D² does not present a
notch to receive G2, then G¹ cannot be thrust out of D' and consequently the lever to
which D¹ belongs is locked. The arrangement shewn in Fig. 3 which illustrates the
system known as tappet and plunger interlocking, forms no part of the present
invention but is described in order to explain how the peculiar movements of the
plungers D, effected as above set forth by a lever and its spring catch, are applied in
this system. Obviously this mode of actuating the plungers may be applied in other
systems in which interlocking is effected by plungers or sliding rods moving with the
levers.
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 we
claim is,
1. The herein described method of actuating the plungers of railway point and
signal interlocking apparatus in three steps by the combined action of the levers and
their spring catches on slides to which the plungers are jointed, substantially as and for
the purpose herein set forth.
2. In combination with a railway point or signal lever and its spring catch, the
lever F with its pins, the slide E with its gabs el e² and the locking plunger D,
arranged and operating substantially as described.
Dated this 27th day of September 1888.
ABEL & IMRAY,
Agents for the Applicants.