IMPROVEMENTS IN APPARATUS FOR ACTUATING AND CONTROLLING RAILWAY POINTS OR SWITCHES AND SIGNALS
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Arthur Walter Pigott at the Office
of the Commissioners of Patents on the 31st March 1883.
ARTHUR WALTER PIGOTT of Gateshead in the County of Durham. Engineer.
"IMPROVEMENTS IN APPARATUS FOR ACTUATING AND CONTROLLING RAILWAY
POINTS OR SWITCHES AND SIGNALS."
The objects of my improvements are to simplify the operating and controlling
parts of the points or switches and signals of Railways to expedite their operation
and to ensure greater certainty of action with consequent greater safety and
economy.
In carrying out my invention I connect to a suitably formed tie rod or connec-
tion between the two points or switch rails of a pair of rails two cranked arms or
parts each such arm or part being formed with an opening through which passes a
bolt or stud or otherwise to serve as a centre of motion and secured to a suitable
base plate, each such arm or part is also formed with three projecting parts one
projection (which may be called the outer one) of each being connected to the tie
rod of the points so as to give motion thereto and receive motion therefrom
alternately in the respective alternate motions of that tie rod when the other of
these projections (which may be called the inner one) is engaged with and operated
by a moveable piece capable of oscillation on a centre of motion attached to and
moving with a sliding locking pioce which slides in guides carried by the base plate
and is actuated from the signal or pointsman's station through the intervention of
suitable cranks and rods or such like well understood means operated by a lever
arm provided with a suitable catch taking into rack teeth on a suitable part
adapted to prevent that lever being incompletely operated-The third or what
may be called the middle projection of each of the two cranked arms or parts serves
to place in correct position or correctly reset and to lock or retain the moveable
piece on the sliding locking piece in its several movements aided by a stud or studs
or projection on such sliding piece-The end of this sliding locking piece is formed
with or carries a bolt to pass into one or other of two holes or recesses or this
locking may be otherwise arranged in a part of the tie rod to the points and so
Price Adi

page_text: luck the points when their change of position has been correctly effected to one or
the other side for the passage of a train or carriage The form of the moveable
piece may be somewhat that of a V. the centre of motion thereof being on a pin or
stud from the sliding piece near the junction of the two limbs and the ends of those
limbs engage with recesses in the before mentioned outer projections of the cranked
parts in turn or the relative forms of these parts for their joint operation may be
varied or the V shaped moveable piece may be substituted by a fixed part or parts
of other suitable form and adapted to operate corresponding parts.
The movement of the points or switch during the passage over it of a train may
be prevented by the employment of a guard rail or a rail over which the wheels of
the train or carriage run and which guard rail is so attached to and operated by
rods and cranks or other suitable connections to the parts operating the points
that before change of position of the points can be effected such guard rail must be
raised, which raising during passage of the train the wheels of the carriage or
carriages prevent
The movements of the signals which respectively block and clear the roads
opened or closed by the respective movements of the points may be effected by the
same operating means which give movement to the points-For this purpose I
provide on the lever arm whereby such movement is originated a piece formed of
two arms crossed capable of turning on an axis from such lever which axis also
carries a ratchet or catch wheel controlled by a suitable stop and spring to prevent
revolution during its return movements which ratchet wheel gears with a rack
borne to it by spring pressure and which rack is carried so as to swing on an axis
at its one end supported by the framework but this motion may be attained by
other known arrangements of gearing adapted to give the desired alternate
motion.
The ends of the crossed arms turning on the axis carried by the operating lever
are alternately in different planes and are presented alternately to and so as
alternately to operate one or other of two levers capable of turning at or towards
their centres or otherwise on pins or studs as axes of motion, the other ends of
"these levers being respectively connected by suitable connections to cranked arms
or connecting levers and thence respectively to the signal arms.
The movements of the signals which block and clear the roads opened or closed
by the movements of the points may be controlled by suitable connections and
cranked arms or such like means from two bent or cranked or other levers or parts
so placed in relation to the holes or parts formed through or upon the tie bar that
one or other of such bent or cranked levers or rods may be operated by the bolt
end or part of the sliding locking piece of the points moving parts and thereby the
locking of the points and signals may be at once obtained or the signals instead of
being simply locked by the movement of the sliding locking piece may be operated
or set by such movement and locked.
The operation of the parts will be as follows. A train having passed say down
the main line the signalman pulls his lever drawing back the sliding locking piece
and disengaging the lock piece from the tie bar of the points also drawing back
therewith the V shaped moveable piece until one end or limb of that piece engages
the inner projection of and causes a movement on its axis to one of the cranked
parts and by its outer projection to the point tie bar and the points to throw them
over and thence in a similar manner motion is given to the other cranked parts.
The lever is then drawn back to its first position and in so doing the sliding
locking part with its locking pin is replaced so as to hold locked the point tie bar
and points and by those movements the signals are set accordingly and so locked
whilst the middle projections of the cranked parts serve to keep the moveable
V shaped piece in correct position and cooperate with a pin or pins or a projection
from the sliding locking piece, to prevent the displacement of that moveable V piece
by vibration or otherwise.
Among the practical advantages arising from the invention are, that one move-
ment in each direction of one lever suffices to effect the whole of the operations for

page_text: shifting the points, locking them in correct position, setting the signals and locking
them also, whilst in the performance of these movements those strains which are
heavy are enable to be done by the parts in tension, and those which are light
may be done by parts in compression.
Suitable connections of a similar character may also be provided for indicating
in the signal box or station the position of the respective points and signals after
their respective movements have been effected.