Improvements in Cut-off Mechanism for Steam and other Engines.
Year: 1893

page_text: Date of Application, 1st Apr., 1893
Complete Specification Left, 4th Oct., 1893-Accepted, 4th Nov., 1893
PROVISIONAL SPECIFICATION.
Improvements in Cut-off Mechanism for Steam and other Engines.
1, JOSEPH WOODS, of 6 Chapel Street, Boston, in the County of Lincoln,
Engineer, do hereby declare the nature of this invention to be as follows:-
This invention relates to improved mechanism for actuating the cut-off valves of
steam and other engines, whereby the cut-off is increased or diminished equally at
each end of the stroke of the valve as the load on the engine varies.
In carrying out the invention I employ a slotted quadrant or link with which
the valve spindle of the cut-off valve engages as hitherto where a slotted link is
employed, but I connect one-end of the link by a rod to a lever pivotted on the
engine frame such lever being connected by a rod to an excentric on the engine shaft,
while the other end of the link is connected by a rod to one end of a lever adjustably
pivotted on the engine frame, the other end of this lever being slotted so as to
engage a pin on the first mentioned lever. By this arrangement the excentric
operates the two ends of the link in opposite directions.
The link is connected to the governor of the engine in the usual manner so that
the variations in the height of the governor balls will adjust the position of the
link relatively with the valve spindle and by reason of the link being operated by
the two rods the movement of the valve will be varied to increase or diminish the
cut-off equally at each end of the stroke of the valve as the load on the engine
varies.
Dated the 1st day of Anril 1893
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Cut-off Mechanism for Steam and other Engines.
I, JOSEPH WOODS, of 6, Chapel Street, Boston, in the County of Lincoln,
Engineer, 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 :-
This invention relates to improved mechanism for actuating the cut-off valves of
steam and other engines, whereby the cut-off is increased or diminished equally at
each end of the stroke of the valve as the load on the engine varies, by means of a
single eccentric.
In carrying out the invention I-employ a slotted quadrant or link with which
-the-valve spindle of the cut-off valve engages as hitherto where a slotted link is
employed, but I connect one end of the link by a rod to a lever pivotted on the
engine frame, such lever being connected by a rod to an eccentric on the engine
shaft, while the other end of the link is connected by a rod to one end of a second
lever adjustably pivotted on the engine frame, the other end of this lever being
slotted so as to engage a pin on the first mentioned lever. By this arrangement a
single eccentric operates the two ends of the link in opposite directions.
The link is connected to the governor of the engine in the usual manner so that
the variations in the height of the governor balls will adjust the position of the link
relatively with the valv. spindle and by reason of the link being operated by the
two rods the movement of the valve will be varied to increase or diminish the

page_text: cut-off equally at each end of the stroke of the valve as the load on the engine
varies.
To enable my invention to be fully understood I will describe the same by
reference to the accompanying drawings, in which :—
Figure 1 is a side elevation of my improved cut-off mechanism; and,
Figure 2 is a sectional plan of the same:
Figure 3 is a view similar to Figure except that the valves and ports are
shewn in plan instead of in elevation, the said figure serving to illustrate the
operation of my improved mechanism.
a is the engine cylinder, 6 the piston, c, c¹ the steam ports, d the exhaust port,
e the ordinary or main slide valve operated by the eccentric f on the crank-shaft. g,
and the cut-off valve; all of which parts are of ordinary construction and require
no further description.
i is the slotted quadrant or link with which the cut-off valve h is in connection
through the medium of the rod ; carrying the block j', the said link being suspended
from the lever k pivotted to an arm upon the governor bracket and connected with
the governor in a well known manner so that the action of the governor will cause
the raising and lowering of the said link. m is a weight attached to an extension
of the lever k for counterbalancing the link i and the connected parts so that the link
can be readily operated by the governor.
n is the lever pivotted to the engine framing or bed at n¹, the said lever being
connected by the rod o to one end of the link and by the rod p to the strap of an
eccentric q upon the crank-shaft g.
is the second lever adjustably pivotted at s to a bracket t upon the engine
frame or bed-plate, the upper end of the said lever being connected by a rod u
with the upper end of the link i whilst the lower end, which is slotted, has within it
a sliding block v pivotted upon a pin wo carried by the lever n.
With this arrangement it will be understood that when the rod p is moved by the
eccentric in the direction of the arrow 1, Figure 1, the lower end of the link will be
moved in the same direction whilst owing to the action of the block v against the
lower end of the lever r the upper end of the said link will be moved in a reverse
direction, thereby producing the required oscillating movement of the said link by
means of a single eccentric.
The position of the link i shewn in Figure 1 is that which the link occupies when
the engine is taking full steam whilst the position shewn in Figure 3 is that which
the link occupies when the governor balls are separated to about their fullest extent,
in which latter position of the link the cut-off valve his in its central position and
the block j connected with the rod j of the said valve h in the position in which no
reciprocating movement is imparted to the said valve h. It will be noticed that,
as shewn in the drawings, this position of the said block is not quite in the centre
of the slot of the link i, this being due to the fact that the oscillation of the upper
end of the said link is not so great as the oscillation of the lower end produced by
the eccentric q.
It will be understood that when the governors are in any intermediate position
between those shewn in Figure 1 and Figure 3 more or less movement will be
imparted to the cut-off valve h in a well known manner.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. Cut-off mechanism for steam or other engines the link of which is oscillated
-by means of a single eccentric through the medium of two levers one of which is
connected to the upper end of the link and the other to the lower end, the said two
levers being connected together in such a manner that the forward movement of
one causes the backward movement of the other and vice versa, substantially as
described.

page_text: 2. The manufacture and use of the improved cut-off mechanism for steam and
other engines hereinbefore described and illustrated in the accompanying drawings.
Dated the 4th day of October 1893.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.