An Improved Automatic "Cut Off Motion" for Steam Engines.
Year: 1886

page_text: Date of Application, 2nd June, 1886.
Complete Left, 2nd Mar., 1887.
Complete Accepted, 5th Apr., 1887. .
An Improved Automatic "Cut Off Motion" for Steam Engines.
We, ROBERT DENNIS, of Eyre Street, GEORGE TRICKLEBANK of Barker Pool FRED
JOHNSON of Walker Street, and FREDERICK MELLOR of Burgess Street, all of Sheffield
in the County of York, Engineers, do hereby declare the nature of our said invention.
for AN IMPROVED AUTOMATIC "CUT OFF MOTION FOR STEAM ENGINES, to be as
follows:-
"
Our invention of an improved automatic cut off motion for regulating the supply
of steam to Steam Engines, has for its object, to accomplish such cut off action by a
simple arrangement of mechanism which can be easily adapted to existing Engine,
or can be built up with Engine, in the ordinary way.
It consists of a frame or standard carrying a revolving shaft upon which is fixed a
tappit-block having a longitudinal sliding motion upon a fixed key or feather, secured
to the shaft.
The said sliding motion is imparted to the tappit block by means of a crank lever
and fork which engages with a neck formed at one end of the tappit-block, the
opposite end of the crank lever being connected with or forming the governor rod; it
will thus be seen that the position of the tappit block is regulated and determined by
the action of the governors, that is, in other words, by the speed of the engine.
The rotary motion of the shaft is or may be obtained in various ways, and it may
be either intermittent or continuous; we prefer to obtain it from the rocking shaft (or
similar intermittent action,) and to transmit such motion to the shaft by means of a
double ratchet, connected to the rocking shaft by means of two connecting rods, in
such a manner that there shall be a movement of the shaft at every stroke of the
piston.
A continuous revolving motion may be used, and may be conveyed from a suitable
revolving part of the Engine by means of bevil wheels.
The tappit block is provided with a number of tappits, (or cams), for example
four, these tappits taper longitudinally, one side being in line with the shaft, and all
the taper being on the other side, which is the back, or drop side.
The top faces of the tappits are made concentric with the shaft, as also is the surface
of the block between the tappits.

page_text: A lever connected with, and operating the throttle valve is conveniently fixed so
that a projecting finger will rest upon the said tappit block, and will be raised by
coming in contact with the tappits, the front sides of which are rounded off so that
the finger may readily climb up on to the face, and drop the moment it passes the
back edge.
When the finger is on the face of a tappit, the throttle valve admits a full flow of
steam, and when it rests upon the body of the block between the tappits the valve is
closed.
It will thus be seen that according to the position of the tappit block, the finger of
the valve lever traverses over the broadest end of the tappit, admitting steam, or over
some other portion, shortening until it comes to a mere point as the speed of the engine
increases, until it rests upon a plain annular surface upon the body of the block at
which position the steam is entirely shut off until the governors drop and the block
is moved back so as to bring the tappits in position opposite the finger of the
valve rod.
The action of the governors thus control with absolute certainty the time and
position of the cut off, and prevent any possibility of the engine racing or running
away.
Dated the 1st da
T
1000
ROBT. F. DRURY,
Agent for the Applicants.

page_text: COMPLETE SPECIFICATION.
An Improved Automatic "Cut Off Motion" for Steam Engines.
We ROBERT DENNIS, of Eyre Street GEORGE TRICKLEBANK of Barker Pool, FRED
JOHNSON of Walker Street, and FREDERICK MELLOR of Burgess Street, all of
Sheffield in the County of York, Engineers do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
Our invention of an improved automatic "cut off" motion for regulating the supply
of steam to the cylinders of Steam Engines has for its object to accomplish such cut
off action by a very simple arrangement of mechanism, which can be easily adapted
and applied to existing engines, or be built up with new engines.
The annexed sheet of drawings illustrates our invention, and similar letters of
reference indicate similar parts in any of the figures in which they occur.
*
Fig. 1, is a front elevation of an automatic apparatus or cut off" made according
to our invention; one or two parts being removed to enable the principal parts to be
clearly seen.
Fig. 2, is a side elevation of same, also with unimportant parts removed.
In carrying our invention into practice, we make a suitable frame or base plate A,
the one shown in the drawings is made of a suitable shape to fit upon the top of the
valve box B; it is also provided with suitable standards C, to carry a revolving
shaft D, which may have a rotary motion imparted to it in various ways, and either
continuous or intermittent, when intermittent it may be obtained from the rocking
shaft, and be transmitted to the said shaft D, by means of a double ratchet fixed upon
the said shaft D, and worked by a connecting rod from the rocking lever, in such a
manner that there shall be a forward movement of the shaft D at every stroke of the
piston.
A continuous revolving motion may be used and may be conveyed from a suitable
revolving motion, or part, of the engine, such as the crank shaft, by means of bevil
wheels; in the drawings this motion is supposed to be derived from the crankshaft
and carried forward by an inclined shaft O, and is transmitted to the shaft D, through
the pair of wheels E, F.
On the shaft D is placed a tappit block G, having two, four, or other suitable
number of tappits H, broad at one end and tapering to a point or thereabouts at the
other.
This tappit block is capable of a longitudinal sliding motion upon a fixed key or
feather I securely fitted to the shaft, the said motion being imparted by means of a
crank lever and clutch-fork J, connected with the governors, and it will thus be seen
and understood, that the tappit block G is moved along the shaft, and its position
thereon determined by the action of the governors, or in other words by the speed of
the Engine.
The tops or faces of the tappits are concentric with the shaft as also is the surface

page_text: of the block between the tappits, and it will be seen in Fig. 1, that all the taper is on
one side, that is the back or dropside.
A lever K is supported by one of the standards, and is connected with the rod L of
the equilibrium valve M. It is provided with a tappit-finger N which rests upon and
travels across the surface of the tappits as the block revolves, the tappits being rounded
off on the front sides so that the finger N, may readily climb on to the face, and drop
the moment it passes the back edge."
When the finger is on the face of a tappit the valve is raised and admits the full
flow of steam, and when it drops between the tappits, being accelerated by the
reaction of a compressed spring P, acting against the end of the valve rod L, the
valve is closed.
Thus according to the position of. the tappit block upon the shaft D, the finger N,
traverses over the broad or narrow part of the face of tappits, and admits or shuts
off the steam as required.
The action of the Governors thus controls with absolute certainty the action of the
cut off, which will effectually prevent the Engine racing or running away, and
economise steam.
We do not bind ourselves to the exact construction of the apparatus as described
and shown, as the details of construction may be considerably varied without departing
from the spirit of our invention, but―
Having now particularly described and ascertained the nature of our said invention,
and in what manner the same is to be performed, we declare that what we claim is :-
1-An automatic "cut off" motion or apparatus constructed substantially as herein-
before described and illustrated.
"
2-In a cut off" apparatus used in connection with Steam Engines, for the
purpose herein before specified, the combination of a tappit block, (such as G)
actuated by the governors, and a finger N attached to a lever K, for opening and closing
the steam valve, substantially as herein before described and shown.
3-A steam cut off" motion consisting of a revolving tappit block with tapering
tappits, and capable of having a longitudinal movement upon its shaft or axis, given to it
by the Governors, in combination with a finger arranged to travel over the tappits,
and to raise a lever operating the steam valve, substantially as hereinbefore described.
Dated the 1st day of March 1887.
RUBI. F. DRURI,
Agent for the Applicants.