AN IMPROVED BRAKE FOR CARRIAGES
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Edmund Edwards at the Office of the
Commissioners of Patents on the 27th October 1882. A communication to
him from abroad by Monsieur Dirat, of Paris, in the Republic of France.
EDMUND EDWARDS, of the firm of Edwards and Co:- Patent Agents and
Engineers, of 40, Southampton Buildings, Chancery Lane, in the County of
Middlesex "AN IMPROVED BRAKE FOR CARRIAGES [A communication to him
from abroad by Monsieur Dirat, of Paris, in the Republic of France.]
"
This invention relates to brakes or drags for carriages, and it has for its object a
novel method of construction by which the brake is simplified, the number of the
parts used in its construction being reduced and the strength and rigidity of the
screw used being increased, as compared with such brakes as ordinarily constructed
and used.
In order to put the invention in operation I attach to one of the flat parts of the
ordinary axle, upon which the springs are supported, an attachment forming the
support for a vertical endless screw and toothed rack into which the screw geara.
This attachment consists of a plate resting upon and attached to the flat part of the
axle below the spring and having a hole through which the toothed rack passes.
The plate also carries a vertical bracket or frame in the upper part of which is a
socket or bearing in which revolves a vertical bar upon the lower part of which the
endless screw is formed, and also a suitably formed hole through which the upper
end of the rack passes and is guided. The lower side of the plate also carries pieces
projecting downward which form the fulcrum of a lever the longer end of which
extends below the axle to about the centre of the length of the latter, whilst its
shorter end is bent down and under the nave of the wheel, and is provided with a
curved plate the upper surface of which is fitted with two friction blocks or brakes
of copper or other suitable material which are raised forcibly against the nave of
the wheel when the longer end of the lever is forced down.
To the flat part of the axle at its opposite end are also attached pieces projecting
downward which form the fulcrum of a second lever of a similar kind the shorter
end of which is provided with a curved plate and friction blocks or brakes which
operate upon the nave of the opposite wheel, whilst its longer end is continued
n
019

page_text: under the axle and brought under the lower end of the rack to which its extremity
is jointed.
The longer end of the first lever is provided with a ring or socket which slides
upon the second lever about the middle of the length of the latter, sufficiently freely
to allow the longer lever to descend and in doing so to force down the first or
shorter lever, so that the brake blocks at the shorter ends of the two levers are
applied simultaneously to the naves of the two wheels.
The lower end of the endless screw is kept in its position by a pivot entering the
end of the screw which revolves upon it, and by a boss or collar immediately beneath
the upper part of the vertical guide already described, and the upper part of the bar
upon which the screw is formed passes through and is guided and steadied by an
eye upon a bracket screwed to the carriage. A handle is fitted upon the upper
end of the bar by which it can be turned round. Inside the vertical guide is
arranged a flexible spring of flat steel which keeps the rack pressed against the
screw sufficiently forcibly to prevent any rattling between them from the jolting
of the carriage.
•
The vertical guide described is preferably closed at its sides so as to keep dust
and dirt from the screw and rack.
The action of the brake is as follows:-the screw being turned by the handle
upon the fixed centre which carries it gives a movement up or down to the rack
the teeth of which are geared with it, and the lower end of which raises or lowers
the end of the longer lever to which it is jointed, which lever' also actuates the
shorter lever with it, the brake blocks being pressed against or withdrawn from
the naves of the two wheels simultaneously.
In order to prevent shock, the socket upon the shorter lever which embraces the
longer one as described should be fitted so that its inner sides touch the latter,
though allowing it to slido and turn sufficiently upon it, and the pin upon which
the longer lever is jointed should pass through an oval or slotted hole.
The brake block is composed-of-a.curved plate or bar formed upon or attached to
the shorter end of the lever, and having two pieces of copper firinly screwed to it,
the screws being made of the same material so that the entire surface may be used
without cutting the iron hoop upon the nave against which they are pressed. The
two pressure pieces should be separated by a sufficient space so that two points of
contact are obtained, and the curved bar in this space is preferably rounded so that
dust or dirt does not collect upon it.