IMPROVEMENTS IN APPARATUS FOR WORKING AND CONTROLLING RAILWAY SIGNAL DISCS
Year: 1862

page_text: PROVISIONAL SPECIFICATION left by Jean Baptiste Thomas at the
Office of the Commissioners of Patents, with his Petition, on the 5th
November 1862.
I, JEAN BAPTISTE THOMAS, of Paris, in the Empire of France, do hereby
declare the nature of the said Invention för "IMPROVEMENTS IN APPARATUS
FOR WORKING AND CONTROLLING RAILWAY SIGNAL DISCS," to be as follows:-
This Invention consists in an improved combination of apparatus by aid of
which railway signal discs may be worked and their action controlled with
greater ease and certainty than by the arrangements at present in general
use.
Figure 1 of the annexed Drawing represents in vertical projection an
application of the present improvements to signal apparatus at the head of the
line. A is a disc of the ordinary form placed beyond the station and acted on
by a horizontal pulley wheel B, round which passes the traction chain X,
secured at the point y to the segment V, No. 2, and terminated by a coun-
terpoise M. The opposite extremity of this chain is linked to the traction
wire P, the other end of which is connected by the chain X¹ with a second
segment V, No. 1, mounted at the station; M¹ is a second counterpoise
attached to the chain X. This counterpoise, which is of lesser weight than M,
serves to maintain the tension of the traction wire and to keep the disc in the
closed position. O is a gorge formed in the circumference of each segment,
and serving as receptacle to the traction chains; L, L, are the axles of the
seguents enclosed in cast-iron boxes. In the side, and near the top of the

page_text: segment V¹, is formed a groove corresponding with and sliding on the semi-
circle H, by which the mechanism is surrounded. G is a lever or hand bar set
on the segment V¹; K is a catch fitted to this lever and serving to maintain
the segment in the "open" position when the line is free. On raising this
catch the disc is again carried to the closed position by the sole action of the
counterpoise M suspended to the traction chain X, No. 2. T is an iron branch
set horizontally on the disc A and striking, when the latter is turned on,
against signal bells mounted at any suitable point of the passing train, thus
warning the engine driver and guards that the line is closed, when by any
accident the signal may have escaped their notice.
Figure 2 represents in horizontal projection an arrangement in which the
working of the discs is effected by the passage of the train before its entry into
the station. D is a horizontal iron shaft mounted on the line close to the disc
and fitted with two rods I, E. To the rod I is attached a chain X which,
being passed round the horizontal pulley B of the disc column, is prolonged to
the segment V, No. 2, where it is fixed, as in the preceding arrangement.
The train, in passing, presses down the rod E, causing the shaft D to revolve,
and thus communicates to the rod I a movement which turns the disc into
the closed position. The wire P communicates the same movement to the
segment V¹ (No. 1) at the station, and the disc is there maintained in the
closed position by a catch, as in K, Figure 1. To return the disc to its
original position when the line is freed this catch K is raised, leaving the
counterpoise free to exert its action. When so required, the movements of
the discs may be communicated by a hand bar, as in G, Fig. 1, No. 1.
Figure 3 represents an arrangement applicable to discs placed on the open
line at a distance from the station. B is the pulley or horizontal wheel of the
pillar, provided with a notch Z corresponding with a check bar C, by which
the disc is maintained in the closed position. Close to this disc is placed a
horizontal shaft provided with two rods I, E, as in the preceding combination.
The line being free and the catch bar at Z, as seen in the Drawing, the train
on its passage presses down the rod E, thus giving a half turn to the shaft D,
which, acting on the rod I, carries the disc to the closed position. In this
movement the notch Z is brought to the level of the catch C, with which it
keys, the latter being pressed against the wheel either by a spring, by a coun-
terpoise, or by a segment, as in q. The traction wire P is carried on to the
next horizontal shaft D¹, placed at any required distance, say, from 1,000 to
2,000 yards. On the passage of the train over this shaft the rod E¹ is pressed
down, and by the traction of the wire disengages the catch C from its hold in
the notch Z', thus leaving the disc free to return to its open position under

page_text: the action of the counterpoise M connected with the segment No. 2. Tho
arrangement above described may be repeated over the whole line.
Figure 4 represents in horizontal projection a combination of straining
mechanism by which the tension of the traction wires is maintained at all
temperatures. ✗" is an iron bar oscillating on a pivot S set in an upright
picket. To each extremity of this bar are attached the traction wires P, P,
which are strained by the counterpoises suspended to the chains of the
segments, as will be seen in the Drawing. The application of this straining
apparatus gives rise to a modification of the catch C by which the line is kept
closed. This catch is so mounted that the chain X tends constantly, under
the action of the counterpoise R, to withdraw it from its notch; but this
tendency is counteracted by the superior weight of the counterpoise R¹, by
which it is kept against the wheel, thus maintaining the closure of the line.
The train, on reaching the second shaft D' slackens the wires P, P, and the
catch giving way under the action of the counterpoise R, the disc is thrown
back to the open position.
To avoid the shock occasioned by the sudden contact of the passing trains
with the rod E of the three preceding combinations, a series of iron bars may
be mounted under the first four or five carriages, forming an inclined plane of
a certain length, which, in passing over the rod, carries it gradually to the
point required for the rotation of the disc.