IMPROVEMENTS IN RAILWAY BREAKS
Year: 1866

page_text: PROVISIONAL SPECIFICATION left by John Clark at the Office of the
Commissioners of Patents, with his Petition, on the 14th November
1866.
I, JOHN CLARK, of Paddington, in the County of Middlesex, Engineer,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN
RAILWAY BREAKS," to be as follows:→
The improvements which constitute this Invention relate in part to the
ordinary breaks, and in part to the means of applying the
The objects of this Invention are, first, to obtain the break power from the
axles or wheels of the train when in motion; secondly, to regulate the power
so obtained as required; thirdly, to introduce between the force applied and
the break blocks self-adjusting media for compensating the wear of the blocks
upon the wheels; fourthly, to compensate or prevent the jar of the carriages
to which breaks are fitted; and, lastly, to improve certain parts of the
mechanism by which the ordinary breaks are applied.
The means by which I propose to effect the improvements are as follows:
"To obtain the break power from the axles or wheels I suspend at the bottom
of a suitable double link hung to the under frame of the carriage an eccentric
light wheel weighted so as to maintain its normal position by gravity when
out of use, when its periphery nearly but not quite touches the axle wheel or
eccentric thereon, and is turned by contact therewith, and thus imparts a
backward and forward motion to the link;. this link is fitted with. a rising

page_text: and falling pawl, which works into a rack on the end of the connecting rod of
the breaks, and thus the required pushing or pulling back power is obtained.
The rack or notched portion of the connecting rod is jointed thereto so as to
rise and fail, and is raised and lowered into and out of gear with the pawl by
a cam turned by the pull of a light chain or cord from either end of the train
by the guard or engine driver. This cam is so arranged that when it lifts the
rack or notched bar it removes a strut which holds the eccentric wheel of the
link out of contact with the axle. To regulate the power thus obtained I fit
a moveable stop upon the rack, the position of which can be adjusted as
required by the pull cord, chain, or otherwise, and prevents the backward and
forward motion of the link and pawl from pushing or pulling more than a
certain distance; the backward or forward motion imparted thereby to the
rack and break connecting rod is maintained by a second pawl, which rises
and falls in a fixed frame, both pawls being out of gear when the rack falls
into its normal position.
For effecting the third above-mentioned improvement instead of fixing the
connecting rod lever to the transverse break shaft I fit it so as to turn thereon.
At the side of this lever or within the same when double I fix to the shaft a
notched quadrant or segmental rack, and at the side or between the lever,
when double, I fit a spring or gravitating pawl, so that the lever can move
freely in one direction without affecting the quadrant or segment, and in the
other will move the same. A second pawl with an elongated eye upon an
independent centre is permanently in gear with the notches, over one of which
it moves when the break blocks are worn to a certain extent, and thus a
self-acting "take-up" or adjustment is obtained. To prevent the jar to the
carriages caused by applying the breaks in the ordinary way I introduce between
the shaft end of the break connecting rod and the main lever a strong spring
coupling, the power of which spring can be regulated as required by a suitable
adjusting media fitted thereto. I also propose to hang the break blocks from
centres at or nearly over the centres of the wheels, so that the drag of the
block by the wheel is transferred from a vertical to a horizontal direction.
I also propose when metal blocks are used to bed them upon a stratum of
india-rubber, cork, or other elastic or semi-elastic material. The pull cord or
chain is passed and coupled transversely at the ends of the carriages for com-
pensating the compression of the buffers, and instead of the pull being arranged
to put on the breaks, as above described, the whole may be arranged so that
the pull shall take off and keep the mechanism out of gear, in which case in
the event of a portion of the train breaking away the breaks thus freed would
be self-applied. The lever and quadrant before described in connection with

page_text: the rocking shaft may be applied as an improvement to and in applying the
ordinary breaks. Provision is made at the end of the rack of the connecting
rod for the power being applied thereto by the ordinary screw and gearing, so
that if necessary the guard can actuate the improved mechanism thereby.
Another improvement which I propose to introduce consists in fitting double
blocks, one above and one below the centre of the wheels, the said blocks
being brought into contact therewith by a right and left hand screw worked
by suitable levers.