Colliery, Winding, or other Engines.
Year: 1885

page_text: Colliery, Winding, or other Engines.
We DAVID GREIG of Leeds in the County of York Engineer and FREDERICK
JOHN ANSON of Leeds aforesaid Engineer do hereby declare the nature of our
Invention for "IMPROVEMENTS IN AUTOMATIC EXPANSION VALVE GEARING FOR
"to be as follows:-
COLLIERY, WINDING OR OTHER ENGINES
According to this invention we arrange expansion gear for colliery winding or
other engines in such manner that the duration of time or portion of stroke that
steam is admitted to the cylinder of the engine may be varied automatically and
so that the valves are always lifted to one fixed height at whatever portion of the
stroke the steam is cut off.
We employ lifting valves both for the exhaust and steam admission valves.
The exhaust valve and steam admission valve for each end of the cylinder of the
engine we couple to lever arms by which they can be raised at the times required.
The lever arms we raise at the required times by arms projecting from opposite
sides of a rock shaft situated between the axes of the valve levers.
The arm which projects from one side of the rock shaft and which acts on the
end of the exhaust valve lever we во shape at its end that when it commences to
lift the exhaust valve lever it lifts it quickly to the required height and then
retains it at this height for the remainder of its upward stroke and until it has
again descended to a position to allow the exhaust valve lever again to descend.
The arm which projects from the opposite side of the rock shaft and which
effects the opening of the steam admission valve is not made to act directly against
the end of the steam admission valve lever but against the end of a trip lever arm
jointed to it so that on the upward movement of the arm on the rock shaft its
end acts against the trip lever and raises the steam admission valve lever and the
valve coupled to it until the end of the arm on the rock shaft travels into a
position in which its end passes up clear of the end of the trip lever--the steam
admission valve then at once closes-When the arm on the rock shaft again moves
downwards it can pass the trip lever as the trip lever is free to turn to allow it to
do so without affecting the position of the valve. The steam admission valve is
thus always lifted to one uniform height,

page_text: One rock shaft and levers such as above described are employed for actuating the
steam admission and exhaust valves for one end of the cylinder and another rock
shaft and levers for the valves for the other end of the cylinder.
Both rock shafts we couple together by a fixed arm extending from one being
coupled by a connecting rod to a fixed arm extending from the other-so that if
one shaft is rocked the other rocks with it.
We give a rocking motion to one of the rock shafts by a slotted arm descending
from it. In the slot is carried a block which can be raised or lowered within it
the block is coupled by connecting links to an ordinary reversing link motion
worked by eccentrics keyed on the crank or other shaft of the engine.
The link from the reversing motion we couple to an arm which turns loosely
upon one of the rock shafts above mentioned whilst a second link connects this
arm with the rising and falling block carried by the slotted arm fixed to the other
rock shaft-This second link we connect near to its extremity to the governor of
the engine so that it may be raised or lowered by the action of the governor and
so allow the governor to control the extent of rocking motion given to the rock
shafts.
Improvements in Automatic Expansion Valve Gearing for
* Colliery, Winding, or other Engines.
We DAVID GREIG of Leeds in the County of York Engineer and FREDERICK
JOHN ANSON of Leeds aforesaid 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 :-
According to this invention we arrange expansion gear for colliery winding or
other engines in such manner that the duration of time or portion of stroke that
steam is admitted to the cylinder of the engine may be varied automatically and
so that the valves are always lifted to one fixed height at whatever portion of the
stroke the steam is cut off.
We employ lifting valves both for the exhaust and steam admission valves.
The exhaust valve and steam admission valve for each end of the cylinder of
the engine we couple to lever arms by which they can be raised at the times
required.
"

page_text: The lever arins we raise at the required times by arms projecting from opposite
sides of a rock shaft situated between the axes of the valve levers.
The arm which projects from one side of the rock shaft and which acts on the
end of the exhaust valve lever we so shape at its end that when it commences to
lift the exhaust valve lever it lifts it quickly to the required height and then
retains it at this height for the remainder of its upward stroke and until it has again
descended to a position to allow the exhaust valve lever again to descend.
The arm which projects from the opposite side of the rock shaft and which
effects the opening of the steam admission valve is not made to act directly against
the end of the steam admission valve lever but against the end of a trip lever arm
jointed to it so that on the upward movement of the arm on the rock shaft its end
acts against the trip lever and raises the steam admission valve lever and the valve
coupled to it until the end of the arm on the rock shaft travels into a position in
which its end passes up clear of the end of the trip lever-the steam admission
valve then at once closes. When the arm on the rock shaft again moves downwards
it can pass the trip lever as the trip lever is free to turn to allow it to do 80
without affecting the position of the valve. The steam admission valve is thus
always lifted to one uniform height.
One rock shaft and levers such as above described are employed for actuating the
steam admission and exhaust valves for one end of the cylinder and another rock
shaft and levers for the valves for the other end of the cylinder.
Both rock shafts we couple together by a fixed arm extending from one, being
coupled by a connecting rod to a fixed arm extending from the other-so that if
one shaft is rocked the other rocks with it.
We give a rocking motion to one of the rock shafts by a slotted arm descending
from it In the slot is carried a block which can be raised or lowerd within it-
the block is coupled by connecting links to an ordinary reversing link motion
worked by eccentrics keyed on the crank or other shaft of the engine.
The link from the reversing motion we couple to an arm which turns loosely
upon one of the rock shafts above mentioned whilst a second link connects this arm
with the rising and falling block carried by the slotted arm fixed to the other rock
shaft. This second link we connect near to its extremity to the governor of the
engine so that it may be raised or lowered by the action of the governor and so
allow the governor to control the extent of rocking motion given to the rock
shafts.
In order that our said invention may be fully understood and readily carried
into effect we will proceed to describe the drawings hereunto annexed.
Figure 1 is a side elevation and Figure 2 is a plan of valve gearing arranged in
accordance with our invention.
a is the stem of the lift or drop valve by which steam is admitted to one end of
the cylinder. a¹ is the stem of the valve admitting steam to the other end of the
cylinder.
b. is the stem of the exhaust valve which opens to allow steam to pass out from
the cylinder at one end. b¹ is the stem of the valve which performs a like duty at
the other end of the cylinder.
The valve stems b. 6' are jointed to lever arms c. c¹ which are capable of turning
freely about centres at c*.
The valve stems a. a¹ are jointed to lever arms d. d¹³ capable of turning about a
centre at d*.
The lever arms d. d¹ carry trip levers e. e¹ jointed to them at e* e* the inner ends
of the trip levers carry adjusting bolts e° which come to abutt on the lever arms.
f. f¹ are rock shafts they are coupled together by arms fx fx and a connecting
rod f**.

page_text: The rock shaft carries an arm g. to operate the exhaust valve and another arm h
to operate the steam valve at the end of the cylinder near which it is situate.
The rock shaft f' carries arms g¹ and h¹ having similar functions.
i is a slotted arm on one of the rock shafts and is a block or die capable of
being moved along the slot A rod k connects the block with a loose suspending
arm . and this by a rod m. is connected with ordinary reversing gear.
The rod k. is connected by parts n n¹ n² with a governor-The governor is
constructed to come into operation at a given speed and it then raises the block or
die in the slot of the arm i thereby increasing the are through which the rock
shafts f. and f¹ play.
As shown in the drawings the parts are in the position they occupy when all the
valves are closed.
At one end the steam valve is on the point of opening and the exhaust valve has
just closed, at the other end the exhaust valve is on the point of commencing
to open.
The opening steam valve is lifted until the end of the arm h escapes from the
trip lever e. the steain valve then at once closes and this will take place sooner or
later according to the amplitude of the arc in which the rock shafts f and f¹ are
moving which again is dependent on the action of the governor.
Directly the parts move from the position in which they are represented in the
drawing one of the exhaust valves is raised from its seat by the arm g¹ and it is
then supported by the arm until the arm arrives at the end of its travel. As the
arm g¹ returns to the position in which it is shown in the drawing it still supports
the valve for a time and then gradually lowers it to its seat.
Thus at either end of the cylinder the steam valve and the exhaust valve are
alternately operated upon by means of the arms g. h and g¹ h¹ projecting from the
rock shafts on opposite sides.
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 expansion gear in which the passage of the steam is controlled by lift or
drop valves operated by arms or tappets on rock shafts which under the control of
a governor oscillate through larger or smaller arcs opening the valves in either case
to the same extent but liberating the steam valve sooner or later according as the
rock shaft performs a larger or a smaller oscillation.
(2.) An expansion gear substantially as herein described.