IMPROVEMENTS IN RAILWAY BRAKES
Year: 1883

page_text: PROVISIONAL SPECIFICATION left by Edmund Edwards at the Office of
the Commissioners of Patents on the 29th January 1883. A communication
to him from abroad by Jean Babtiste Charlier, of Nimes, in the Republic of
Franco
EDMUND EDWARDS, of the firm of Edwards and Co:, Patent Agents and
Engineers, of 40, Southampton Buildings, Chancery Lane, in the County of Mid-
dlesex "IMPROVEMENTS IN RAILWAY BRAKES [A communication to him from
abroad by Jean Babtiste Charlier, of Nîmes, in the Republic of France]
"
This invention relates to brakes used for the purpose of retarding or stopping
carriages upon railways.
Assuming that the invention is to be applied to a railway carriage running
upon six wheels, the improved apparatus consists of a longitudinal frame preferably
of metal formed of two parts bolted together.
The two ends of this frame branch out laterally and are then brought down
vertically inside the end pairs of wheels, vertical slots being formed in them through
which the axles of the wheels pass. A second longitudinal frame passes below
that already described and below the middle axle, its ends being fitted upon the
two outer axles.
Upon the middle axle slides an endless screw having a right handed thread at
one end and a left handed thread at the other end, this screw gearing with and
driving a corresponding toothed pinion upon a vertical shaft the lower end of which
is connected with but turns freely in a bearing in the lower longitudinal frame
described. The upper part of the vertical shaft is screwed and passes through a
corresponding screwed nut the circumference of which is circular but having a flat
face formed upon one of its sides. The nut turns freely, together with the screwed
shaft, in a bearing in the upper longitudinal frame first described.
A longitudinal bar capable of moving for a short distance end ways in supports,
extends the full length of the frame and is provided with a lateral projection in
such a position that when the bar is forced end ways the projection comes opposite
to the flat place upon the nut and prevents the latter from revolving. A helical
spring brings back the bar to its original position when desired. The bar is forced
endways as described by a wedge forced down against its end by a screw and hand
wheel operated by an attendant when desired, and the wedge may be arranged

page_text: between the ends of two adjoining longitudinal bars so that when it is forced
down the two bars are forced apart endways.
The action of the apparatus is as follows:-When the train is travelling at any
speed, the endless screw upon the middle axle, the corresponding toothed pinion,
the vertical screw and the nut, revolve freely, and the upper frame is raised
together with brake blocks which are formed upon or fixed to its descending
ends so as to press upon the rails upon each side of the four outer wheels
when the frame is forced down. To stop the train, the hand wheel is turned and
the wedge depressed, the projection upon the longitudinal bar being thus
brought opposite to the flat side of the nut which is so prevented from turning.
The vertical screw therefore screws into the fixed nut and in doing so draws
it down together with the upper longitudinal frame, and the brake blocks which
are forced against the rails. The screw then continuing to turn rises in the nut
and lifts with it the lower longitudinal frame and the two end axles which with
their wheels revolve freely in the air, and the train is quickly brought to rest.
When the wedge is raised the longitudinal bar is brought back to its original
position by the helical spring or by a knob at its outer end, and the nut then
revolves freely in the upper frame which rises and lifts the brakes from the rails,
the vertical screw descending and with it the lower frame so that the wheels are
brought down again to their place upon the rails.