Improvements in Automatic Cut Off Apparatus for Winding Engines and the like.
Year: 1892

page_text: Date of Application, 6th Oct., 1892
Complete Specification Left, 20th May, 1893-Accepted, 1st July, 1893
PROVISIONAL SPECIFICATION.
Improvements in Automatic Cut Off Apparatus for Winding Engines
and the like.
We, ROBERT THORNEWILL and ALFRED DAVIES both of Iron Works,
Burton-on-Trent in the County of Stafford, Engineers do hereby declare the
nature of this invention to be as follows:-
:-
This invention bas for its object a method of automatically cutting off the steam
and allowing for expansion in winding and other like engines where the speed
rapidly increases from zero and where it is desirable in the middle and still more
the latter portion of the run to work expansively whereas the maximum power is
required at the start. Pivoted on the steam valve rod we place a spring bell crank
trip lever and preferably on the axis of the oscillating lever actuating the valve rod
we place a cam suitably linked to the governor. One (preferably the long) arm of
the trip lever aforesaid bears on the cam surface of this cam while the oscillating
lever actuating the valve stem bears upon a hardened toe piece on the smaller bell
crank of the trip lever. The lever actuating the valve rod has also a toc piece
working against that on the trip lever and both it and the trip lever have sloping
side faces for the purposes hereafter set forth. The trip lever further is provided
with a hard surface at a point at which it bears on the valve rod.
The mode of action is as follows:-
-
The toe piece of the actuating lever rising at each oscillation and pressing
against the toe piece of the trip lever raises the valve rod, the latter afterwards
falling by its own weight aided by a spring cushion or otherwise. As long as the
governor does not bring the cam into play, the actuating lever this works con-
tinuously through the upward stroke on the trip lever and consequently on the
valve rod. Where however the proper maximum speed is attained the governor
presses the cam forward until as the valve rod rises the long arm of the trip
lever comes in contact with the cam and cannot rise any further, the actuating lever
however continues to press upwards until the end of the long arm of the trip lever
being held stationary by the cam, the other arm oscillates outward until the two
toe pieces no longer come in contact; the valve rod then at once falls but the
actuating lever continues its journey. In the meantime the trip lever has gone
back to its normal position and as the actuating lever descends its sloping side face
pushes back the sloping side face of the trip lever until the two toe pieces pass each
other when the trip lever again falls into the normal position being actuated by the
spring, and the oscillating lever again commences to lift it with a fresh stroke.
It will be obvious that the further the cam is pressed over the shorter distance
will the actuating lever be able to raise the valve rod before the two toe pieces
cease to continue in contact and thus terminate the stroke of the valve.
It will be obvious from the foregoing that almost any arrangement of cam having
a sloping surface and actuated by the governor will perform the action, it being not
Decessary that the cam should be pivoted as it could slide horizontally or otherwise
in guides, furthermore under some circumstance the arrangement can still further
be simplified by causing the governor to work directly on the trip lever or its
equivalent, the sole point being to so arrange the mechanism that the length of
contact between the two toe pieces or their equivalent is regulated by the
governor.
Dated the 5th day of October 1892.

page_text: COMPLETE SPECIFICATION.
Improvements in Automatic Out Off Apparatus for Winding Engines
and the like.
We, ROBERT THORNEWILL and ALFRED DAVIES both of Iron Works,
Burton-on-Trent in the County of Stafford, 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:-
This invention has for its object a method of and apparatus for automatically
cutting off the steam and allowing for expansion, in winding and other like engines,
where the speed rapidly increases from zero, and where it is desirable to work
expansively, at an early portion of the stroke, whereas the maximum power is
required at the start.
The invention is best described by aid of the accompanying drawings, in
which―
Figure is an elevation of complete gear of one of a pair of engines :
Figure 2, an enlarged view of part of the mechanism."
In these, A is the steam valve rod; pivotted to this at a is a bell crank lever B.
C is a spring pressing against the short arm of the said lever. The position and
arrangement of this spring are immaterial however, so long as it has a tendency to
keep the lever in the normal position shown in the drawing. D is an actuating
lever on a short shaft d mounted on a fixed pedestal. Worked free on this axis d
is a cam G. H is the governor. This is linked to the cam G by rods or link
gearing I I.
One arm of the trip lever B, preferably the longest one F, is BO
arranged as, under certain conditions, to come in contact with the cam surface g of
the cam G. K is a hard level toe piece on lever B, and M is a second similar toe
piece on lever D. The sides of these levers at L L are made sloping. The trip
lever B is further provided with a hardened surface J, where it bears upon the
valve rod A, and the valve rod can be supplied with a similar and opposing
hardened surface.
The mode of action is as follows-
The apparatus being in the position shown in the drawing and the shaft don
which the lever D is fixed being moved by the link motion, the toe piece M rises
against the toe piece K, and consequently the hardened part J bears upon the
rod A, and raises it. When, however, the point f of trip lever B comes in contact
with the cam G, it can rise no further, and, as the M end of lever D still rises, and
with it the lever B also rises, the said lever B is obliged to oscillate on its axis a
until the toe pieces K and M no longer remain in contact, and the sides L and L
slide over each other. The valve rod A then falls, closing the valve. The exact
time at which this takes place depends upon the governor, as it is obvious that, if
the governor has pulled forward the rod I, and with it the cam G, the point will
come in contact with the flange much sooner than if the rod I had been pushed in
the reverse direction, and had pressed the cam G towards the rod E. The
actuating lever D continues its journey, and, on its return stroke, the two sloping
sides L L slide over each other until the toe piece M stands at a lower level than
the toe piece K. The spring C then presses the shorter arm of lever B back into
the position set forth in the drawing. It is now ready for a fresh stroke. It is
obvious from the foregoing that almost any arrangement of cam, actuated by the
governor, will perform the action. It is not necessary that the cam should be
pivotted, as it could slide horizontally or at an angle in guides, furthermore, under
some circumstances, the arrangement can be still further simplified by causing the
governor to work directly on the trip lever B, the sole point being to so arrange
mechanism that the length of contact after the commencement of the stroke between
the two toe pieces is regulated by the governor.

page_text: 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. The improvement in automatic cut off apparatus for winding engines and the
like, which consists in the combination of a piece of mechanism D working during
its operative period synchronously with the piston rod, a trip lever B pivotted on
the valve rod, and the connection with the governor, so arranged as to draw out
the lever B from contact with lever D, at such portions of the stroke as the action
of the governor shall regulate, lever B being prevented from oscillating too far in
one direction by an abutment on the valve rod.
2. The valve actuating apparatus substantially as herein described and
illustrated.
Dated this 19th day of May 1893.
WM. P. THOMPSON & Co.,
Of Liverpool, Manchester, Nottingham, and London, Patent Agents.