OR IM- PROVED APPARATUS OR MECHANISM FOR PREVENTING OR DIMINISHING INJURY TO STEAM ENGINES ON THE BREAKING OF THE CRANK PIN OR OTHER LIKE ACCIDENT
Year: 1871

page_text: LETTERS PATENT to Thomas Cartwright, of West Bromwich, in the
County of Stafford, Engineer, for the Invention of "NEW OR IM-
PROVED APPARATUS OR MECHANISM FOR PREVENTING OR DIMINISHING INJURY
TO STEAM ENGINES ON THE BREAKING OF THE CRANK PIN OR OTHER LIKE
ACCIDENT."
Sealed the 5th January 1872, and dated the 18th July 1871.
PROVISIONAL SPECIFICATION left by the said Thomas Cartwright at
the Office of the Commissioners of Patents, with his Petition, on
the 18th July 1871.
OR
I, THOMAS CARTWRIGHT, of West Bromwich, in the County of
Stafford, Engineer, do hereby declare the nature of the said Invention
for "NEW
OR IMPROVED APPARATUS OR MECHANISM POR PREVENTING
DIMINISHING INJURY TO STEAM ENGINES ON THE BREAKING OF THE CRANK PIN
OR OTHER LIKE ACCIDENT," to be as follows:-
On the breaking of the crank pin of a steam engine or on the occur-
rence of such other accident as permits the piston of the engine to move

page_text: beyond its ordinary or normal range great injury is frequently done to
the engine before it can be brought to rest.
My Invention has for its object to prevent or diminish such injury,
and consists of the apparatus or mechanism herein-after described for
immediately shutting off the steam from the cylinder of the engine
whenever the piston rod rises higher or descends lower than is compatible
with the proper working of the engine.
The said apparatus or mechanism is constructed as follows:-To the
top of the piston rod of the steam engine an arm or bracket is fixed,
the said arm carrying a ring in which a vertical rod is situated. This
rod, herein-after called the safety rod, is much smaller in diameter than
the hole in the ring, so that during the working of the engine the said
ring is carried up and down upon the said rod but without touching it.
On the said safety rod two stop collars are fixed by means of binding
screws. One of these stop collars is fixed at a point on the safety rod
just below the lowest position which the ring carried by the piston rod
reaches, and the other stop collar is fixed on the safety rod just above
the highest position which the ring on the piston rod rises to on the
working of the engine. When by the breaking of the crank pin or other
like accident the piston descends lower or ascends higher than during
the proper working of the engine, the said ring strikes either the upper
or lower stop collar, thereby moving upwards or downwards the safety
rod on which the stop collar is affixed and shutting off the steem in the
following manner :-The top of the said safety rod is jointed to one end
of a lever turning on a centre fixed over the beam of the engine, the
other end of the said lever having a descending rod parallel to the
safety rod. The lower end of the said second rod terminates near the
valve box and operates upon the valve as follows:-The said second
rod is connected with a crank turning upon a horizontal axis, which
axis carries a vertical lever, the ends both of the upper and lower
branches being rounded. Bearing against both ends of this lever is a
vertical rod carried by a sliding horizontal rod and kept to its bearing
against the lever by a coiled spring. The upper end of this vertical
rod supports or props the horizontal arm of a cranked weighted lever.
To the angle or elbow of the said cranked lever a connecting rod is
jointed, and the latter is jointed at its end to a sliding wedge. This
wedge when in its normal position props up or supports the arm by
which the valve rod is actuated. The said valve rod is heavily weighted

page_text: at top so that when the last described arm is not propped up the weight
forces down the valve rod and closes the valve.
The action of the apparatus is as follows:-On the occurrence of an
accident of the kind herein-before described the ring carried by the
piston rod strikes one of the stop collars, thereby raising or lowering the
safety rod on which they are fixed and communicating motion to the
parallel rod. This raises or depresses the crank to which it is connected,
and the lever on the same axis presses back the vertical rod which
propped up the weighted cranked lever described. The said lever being
no longer supported falls by the weight attached to it and draws the
sliding wedge from under the arm of the valve rod. The said valve rod
being no longer supported is pressed down by the weight at its top and
the valve closes. The steam is thereby shut off and the engine comes
to rest. The operation of the parts is so rapid that the injury which
ordinarily happens to the steam engine under like circumstances is
almost or wholly prevented.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Cartwright in the Great Seal Patent
Office on the 17th January 1872.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
CARTWRIGHT, of West Bromwich, in the County of Stafford, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighteenth day of July, in the year
of our Lord One thousand eight hundred and seventy-one, in the thirty-
fifth year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto me, the said Thomas Cartwright, Her special licence
that I, the said Thomas Cartwright, my executors, administrators, and
assigns, or such others as I, the said Thomas Cartwright, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "NEW OR IMPROVED
APPARATUS OR MECHANISM FOR PREVENTING OR DIMINISHING INJURY TO STEAM

page_text: ENGINES ON THE BREAKING OF THE CRANK PIN OR OTHER LIKE ACCIDENT," upon
the condition (amongst others) that I, the said Thomas Cartwright, our
executors or administrators, by an instrument in writing under my, or
their, or one of their hands and scals, should particularly describe and
ascertain the nature of the said Invention, and in what manner the
same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Thomas Cartwright, do hereby
declare the nature of the said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained in
and by the following statement thereof, that is to say :-
On the breaking of the crank pin of a steam engine or on the
occurence of such like accident as permits the piston of the engine to
move beyond its ordinary or normal range great injury is frequently
done to the engine before it can be brought to rest.
My Invention has for its object to prevent or diminish such injury,
and consists of the apparatus or mechanism hercin-after described for
immediately shutting off the steam from the cylinder of the engine
whenever the piston rod rises higher or descends lower than is com-
patible with the proper working of the engine.
The said apparatus or mechanism is constructed as follows:-To the
top of the piston rod of the steam engine an arm or bracket is fixed,
the said arm carrying a ring in which a vertical rod is situated. This
rod, herein-after called the safety rod, is much smaller in diameter than
the hole in the ring, so that during the working of the engine the
said ring is carried up and down upon the said rod, but without touching
it. On the said safety rod two stop collars are fixed by means of
binding screws. One of these stop collars is fixed at a point on the
safety rod just below the lowest position which the ring carried by
the piston rod reaches, and the other stop collar is fixed on the safety
rod just above the highest position which the ring on the piston rod
rises to on the working of the engine. When by the breaking of the
crank pin or other like accident the piston descends lower or ascends
higher than during the proper working of the engine, the said ring
strikes either the upper or lower stop collar, thereby moving upwards
or downwards the safety rod on which the stop collar is affixed and
shutting off the steam in the following manner :-The top of the said

page_text: safety rod is jointed to one end of a lever turning on a centre fixed
over the beam of the engine, the other end of the said lever having a
descending rod parallel to the safety rod. The lower end of the said
second rod terminates near the valve box and operates upon the valve as
follows:-The said second rod is connected with a crank turning upon
a horizontal axis, which axis carries a vertical lever, the ends both of
the upper and lower branches being rounded. Bearing against both
ends of this lever is a vertical rod carried by a sliding horizontal rod and
kept to its bearing against the lever by a coiled spring. The upper
end of this vertical rod supports or props the horizontal arm of a
cranked weighted lever. To the angle or elbow of the said cranked
lever a connecting rod is jointed, and the latter has at its end a sliding
wedge. This wedge when in its normal position props up or supports
the arm by which the valve rod is actuated. The said valve rod is
heavily weighted at top so that when the last described arm is not
propped up the weight forces down the valve rod and closes the
valve.
The action of the apparatus is as follows:-On the occurence of an
accident of the kind herein-before described the ring carried by the
piston rod strikes one of the stop collars, thereby raising or lowering the
safety rod on which they are fixed, and communicating motion to the
parallel rod. This raises or depresses the crank to which it is connected,
and the lever on the same axis presses back the vertical rod which
propped up the weighted cranked lever described. The said lever being
no longer supported falls by the weight attached to it, and draws the
sliding wedge from under the arm of the valve rod. The said valve
rod being no longer supported is pressed down by the weight at its
top and the valve closes. The steam is thereby shut off and the engine
comes to rest. The operation of the parts is so rapid that the injury
which ordinarily happens to the steam engine under like circumstances
is almost or wholly prevented.
Having explained the nature of my Invention I will proceed to
describe with reference to the accompanying Drawings the manner in
which the same is to be performed.
Figure 1 represents in side elevation a portion of a beam steam engine
to which my Invention is applied; Figure 2 represents a side elevation,
and Figure 3 a plan drawn of the full size of that part of the apparatus
or mechanism placed upon the valve box of the engine.

page_text: The same letters indicate the same parts in each Figure of the Drawings.
Near the top of the piston rod a of the steam engine (Figure 1) is an
adjustable arm or bracket provided with a ring c. Situated parallel to
the piston rod a is a safety rod d passed through the ring c as represented
during the working of the engine, the ring c is carried up and down
the rod d, but without touching it. On the safety rod d two adjustable
stop collars e, f, are fixed. These stop collars may be fixed at any
required distance apart on the safety rod d. The stop collar e is fixed
on the rod d just below the lowest position which the ring c carried by
the piston rod a reaches, and the other stop collar fis fixed on the rod d
just above the highest position which the said ring c rises to on the
working of the engine. The upper end of the safety rod d is jointed
through the lever g over the beam of the engine to a parallel rod h.
The lower end of the rod / is connected with the mechanism placed on
the top of the valve box i for the purpose of operating upon the valve
in the said box. I will describe this mechanism with reference to the
full size views, Figures 2 and 3. The bottom of the parallel rod is
connected to the crank k on the end of the horizontal axis 1. The
axis carries a vertical lever m, m², the ends both of the upper and
lower branches.of the said lever being rounded as seen in Figure 2. 22
is a vertical rod or prop carried by a sliding horizontal rod p, the said
rod p passing through the axis and being supported by the supports q, r.
By means of a coiled spring & pressing the rod p towards the lever m, m²,
the rod or prop n is made to bear against both branches of the said
lever m, m³, as seen in Figure 2; t is a cranked weighted lever turning
on the centre on the upright r. The inner horizontal arm of the
cranked levert is forked, as seen in Figure 3. The top of the vertical
arm or prop n is provided with a shoulder or scat n³ upon which the
levert rests in order to prop or support the said lever (see Figure 2).
To the angle or elbow of the cranked levert the connecting rods u, u,
are jointed at u, u², each connecting rod having at its end a wedge v
capable of sliding in the hollow pillar w; x is the valve rod passing into
the valve box i (Figure 1) and acting upon the valve in the usual way.
The said valve rod is weighted at top by the weight x³, which tends to
force down the valve rod and close the valve in the box i. To the
weighted valve rod x an arm y is connected, the said arm y carrying
a wedge y² which slides in the hollow pillar w above the wedges v, v,
on the horizontal rods u, u. When the wedges v, v, are in their normal
position, as illustrated in the Drawing, they are situated under the

page_text: wedge y of the arm y of the valve rod a and thereby prop or support
the said army and maintain the valve in the box i in its open position.
The end of the valve rod y may be jointed to a vertical support not
shown in the Drawing. The whole of the parts represented in Figures 2
and 3 are carried by the plate 2, which constitutes the top of the
valve box i or is affixed to the top of the said box i.
The action of the apparatus is as follows:-When by the breaking
of the crank pin or other like accident the piston descends lower or
ascends higher in its cylinder than during the proper working of the
engine, the ring c carried by the piston rod a strikes one or other of
the stop collars e, f. On striking the stop collar e or f the safety
valve d is raised or lowered and its motion communicated through the
lever g to the parallel rod which raises or depresses the crank k of
the axis. By the partial rotation thus given to the axis one or other
of the arms of the lever m, m³, on the said axis presses back the
vertical rod n which propped up the weighted lever t. The said lever t
being no longer supported falls by its own weight, the said lever turning
on the centre t². A sliding motion is thereby given to the connecting
rods u, u, jointed to the said lever t, and the wedges v, v, of the said
rods are drawn from under the wedge y of the valve rod arm y. The
valve rod x being thus unsupported is pressed down by the weight x²
at its top and the valve in the box i closes. The steam is thereby shut
off and the engine comes quickly to rest. By the use of the apparatus
described and represented the steam is immediately shut off from the
cylinder of the engine when the piston moves beyond its ordinary or
normal range, and the injury which ordinarily happens to the steam
engine under like circumstances is almost or wholly prevented.
In applying my Invention to horizontal steam engines the parallel
rod 1, Figure 1, is omitted, and the safety rod d provided with the stop
collars e, f, is situated horizontally and jointed directly to the crank k,
the eye c of the bracket fixed on the horizontal piston rod acting
upon the stop collars e, f, of the safety rod in the manner herein-before
described with respect to a beam engine.
My Invention is applicable to steam engines generally.
Having now described the nature of my Invention and the manner
in which the same is to be performed, I wish it to be understood that I
do not limit myself to the precise details herein described and illustrated,
as the same may be varied without departing from the nature of my

page_text: Invention; but I claim as my Invention the new or improved apparatus
or mechanism for preventing or diminishing injury to steam engines
on the breaking of the crank pin or other like accident herein-before
described, and illustrated in the accompanying Drawings, that is to
say, the construction and arrangement or combination substantially as
described and illustrated of the parts of the said apparatus or mechanism
for immediately shutting off the steam from the cylinder of the engine.
whenever the piston rod rises higher or descends lower than is com-
patible with the proper working of the engine, the said apparatus or
mechanism being brought into action by an arm or bracket fixed on the
piston rod of the engine.
In witness whereof, I, the said Thomas Cartwright, have hereunto
set my hand and seal, this Twelfth day of January, in the year
of our Lord One thousand eight hundred and seventy-two.
Witness,
WILLIAM CARTWRIGHT,
West Bromwich.
THOMAS CARTWRIGHT. (L.S.)