Year: 1886

page_text: Date of Application, 5th May, 1886.
Complete Left, 26th Jan., 1887.
Complete Accepted, 1st Mar., 1887
I JOHN HADFIELD STREET of No. 55 Woodlands Street Smethwick in the County
of Stafford Engineering Draughtsman do hereby declare the nature of this Invention
to be as follows:-
My invention consists of mechanism of the kind hereinafter described having for its
object to regulate the speed of steam and compressed air engines by causing the
governor of the engine so to operate upon the slide valve as to cut off the steam or
compressed air at an earlier part of the stroke of the piston when the engine is working
too fast and at a later part of the stroke when the engine is working too slowly and
thus to preserve an approximate uniformity in the speed of the engine.
I will describe my invention in connection with a steam engine.
I use the ordinary slide valve and supplement it with mechanism constructed as
follows: Connected with the governor of the engine is a rod having motion in a line
parallel to the piston rod. The said rod actuates two levers which I will call knock off
levers situated respectively at opposite ends of the slide valve and turning on fixed
centres. These knock off levers are so geared together that they move in opposite
directions.
The normal position of these levers is at about right angles to the axis of the cylinder
and they are inclined on one or other side of the normal position by the governor when
the speed of the engine is too high or too low. As the construction and action of these
two fevers is the same I will describe only one of them and the parts on which it
operates. A rod actuated by an eccentric on the crank shaft of the engine gives a to
and fro motion to a hollow cylinder each end of which carries a tripping piece con-
sisting of a vertical lever carrying on a sido arm a square plate which plate when the
tripping lever is in its normal position engages against a catch plate carried by a rod
the axis of which is coincident with the axis of the hollow cylinder referred to. These
rods and the said hollow cylinder are supported on two rocking levers. Each of the
said rods is connected to the hollow cylinder by means of a hollow piston fixed on
the end of the rod which piston slides in the said hollow cylinder.
A coiled spring

page_text: occupying the interior of the said hollow pistons tends to press them apart and force
their rods out of the ends of, the hollow cylinder. At the required times as herein-
after explained the said hollow pistons are forced inwards and locked in that position
by an adjustable stop against which the end of the valve spindle strikes when the
hollow cylinder approaches the end of its stroke. By the arresting of the end of the
valve spindle the continued motion of the hollow cylinder causes the said cylinder to
advance on the said valve spindle thereby compressing the spring. When the hollow
cylinder has reached a position in which the plate carried by the side arm on the
tripping piece can engage behind the catch plate the engagement is effected by the
action of a spring or springs carried by the hollow cylinder.
The action of the parts is as follows. If the engine is running at too high a speed
the governor inclines the knocking off lever in a greater or less degree to its normal
position. The result of this is that as the hollow cylinder advances it strikes at an
carly point in its stroke against the end of the knock off lever thereby liberating the
tripping piece. The hollow piston advances from out of the end of the hollow cylinder
and the cut off valve coming into early action cuts off steam and thereby reduces the
speed of the engine. It will be understood that as the valve mechanism described
moves in either direction the tripping piece at one end is liberated sooner or later
according to the speed of the engine acting through the governor on the position of the
knocking off piece while at the other end the tripping piece is being locked by the
action of the stop described compressing the spring.
When the speed of the engine is below the arranged normal speed the governor
inclines the knocking off lever to its normal position in a direction opposite to that in
which it is inclined when the speed of the engine is too high.
The opposite ends of the said levers now act upon the tripping pieces and producing
an action substantially the reverse of that hereinbefore described increase the speed
of the engine.
W. T. WHITEMAN,
Agent for the Applicant.

page_text: I JOHN HADFIELD STREET of No. 55 Woodlands Street, Smethwick, in the
County of Stafford, Engineering Draughtsman, do hereby declare the nature of my
Invention and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement
My invention consists of mechanism of the kind hereinafter described having for its
object to regulate the speed of steam and compressed air engines by causing the
governor of the engine so to operate upon the slide valve as to cut off the steam or
compressed air at an earlier part of the stroke of the piston when the engine is
working too fast and at a later part of the stroke when the engine is working too
slowly and thus to preserve an approximate uniformity in the speed of the engine.
I will describe my invention in connection with a steam engine.
I use the ordinary slide valve and supplement it with mechanism constructed as
follows:-Connected with the governor of the engine is a rod having motion in a line
parallel to the piston rod. The said rod actuates two levers, which I will call knock
off levers, situated respectively at opposite ends of the slide valve box and turning on
fixed centres. These knock off levers are so geared together that they move in
opposite directions. The normal position of these levers is at about right angles to
the axis of the cylinder and they are inclined on one or other side of the normal
position by the governor when the speed of the engine is too high or too low. As the
construction and action of these two levers is the same I will describe only one of
them and the parts on which it operates. A rod actuated by an eccentric on the crank
shaft of the engine gives a to and fro motion to a hollow cylinder each end of which
carries a tripping piece consisting of a vertical lever carrying on a side arm a square
plate which plate when the tripping lever is in its normal position engages against a
catch plate carried by a rod the axis of which is coincident with the axis of the hollow
cylinder referred to. These rods and the said hollow cylinder are supported on two
rocking levers. Each of the said rods is connected to the hollow cylinder by means
of a hollow piston fixed on the end of the rod, which piston slides in the said hollow
cylinder. A coiled spring occupying the interior of the said hollow pistons tends to
press them apart and force their rods towards the ends of the hollow cylinder. At
the required times as hereinafter explained the said hollow pistons are forced inwards
and locked in that position by an adjustable stop against which the end of the cut off
valve spindle strikes when the hollow cylinder approaches the end of its stroke. By
the arresting of the end of the cut off valve spindle the continued motion of the hollow
cylinder causes the said cylinder to advance on the said rod thereby compressing the
spring. When the hollow cylinder has reached a position in which the plate carried
by the side arm on the tripping lever can engage behind the catch plate the
engagement is effected by the action of a spring or springs carried by the hollow
cylinder.

page_text: I will now proceed to describe with reference to the accompanying Drawing the
manner in which my invention is to be performed. Figure 1 represents in end
elevation the valve box of a steam engine to which cut off or expansion gear con-
structed according to my invention is applied, a portion of the cut off gear being
situated outside the valve box and a portion inside the valve box; Figure 2 represents
in longitudinal vertical section the cut off gear situated outside the valve box and
represented on the left hand side of Figure 1 and Figure 3 represents in longitudinal
vertical section the slide valve and the portion of the cut off gear situated in the valve
box Figure 4 represents a portion of Figure 2 drawn to a larger scale. The section
Figure 2 is taken on the line a Figure I and the section Figure 3 is taken on the
line Figure 1. The same letters of reference indicate the same parts in the several
Figures of the Drawing.
One
A is the slide valve box and A2 the slide valve worked by the rod A³ operated by an
eccentric on the crank shaft of the engine in the ordinary way; B B are the cut off
valves working upon the slide valve A and opening and closing at the proper times
the steam ports in the said slide valve; B2, B2 are the spindles of the cut off
valves B, B. The cut off valves B B are connected to the regulating mechanism of
the cut off gear situated at the outside of the valve box and represented in Figures 1.
and 2, in the manner hereinafter explained. The mechanism at the side of the valve
box A for operating and timing the cut off valves B, B consists of the following parts.
At each end of the valve box A is a knock off lever. These levers are marked
respectively d and e. They turn upon fixed centres at d², e² and are coupled together
by the connecting rod d³ so that they move in opposite directions. It will be seen by
an examination of Figure 1 that the ends of the arms of each of the knock off
levers d, e are bent at right angles to their middle parts. Jointed to the knock off.
lever d is a rod c (see Figure 2) connected to and operated by the governor of the
engine. The knock off levers d, e are capable of motion through the ares indicated in
Figure 2 but their normal position is at about right angles to the axis of the hollow
cylinder g. They are inclined on one or other side of the normal position by the
action of the governor when the speed of the engine is too high or too low.
In the
drawing the knock off levers d, e have been moved by the governor into a position for
reducing the speed of the engine as herein after explained. The hollow cylinder g has
a to and fro motion given to it by the rod factuated by an excentric on the crank
shaft of the engine. The end of the rod f which is connected to the cylinder 9 near
its middle has a loop or sling in which the said hollow cylinder g is situated.
branch only of the sling of the rod is represented in Figure 2 but both branches are
shown in section in Figure 1 and are marked f. The rod f working the cylinder of
the cut off regulating mechanism and the rod A³ of the slide valve A move together
and at the same rate of motion. The reciprocating hollow cylinder g carries at each
end a tripping lever h, h² of the same construction. The upper end 2 of each tripping
lever is jointed and can be turned outwards, the said jointed upper end being pressed
inwards by a light spring v. These tripping levers are for the purpose of temporarily
connecting or locking one or other of the rods 1, with the to and fro cylinder g, one
of the said tripping levers being in action while the other tripping lever is out of
action (see Figure 2), the said tripping levers being operated upon by the knock off
levers d and e as hereinafter explained. The appliances for locking the tripping levers
with the rods 1, 2 are as follows:-Each of the tripping levers carries a side arm to
which a square plate i is fixed. The plate i when the tripping lever is in its
normal position engages against the back of a catch plate k, see the right hand end of
Figure 2 and the enlarged view Figure 4. The two catch plates k, are carried by
the rods 1, fixed to the hollow pistons n n² sliding in the cylinder g. By means of a
coiled spring p within the two pistons n, n² their rods 1, 2 are pressed apart so as to
force them outwards or towards the ends of the cylinder g. By this construction the
rods, can have motion independent of that of the cylinder gas herein after
explained. The rods 1, and hollow cylinder g are supported on the two rocking
lovers m, m on the cross shafts m², m² the said shafts m², m³ passing through the ends
of the valve box A. On those parts of the cross shafts m², m³ within the valve box A
12

page_text: are other rocking levers m³ m³ working in slots in the spindles B' B' of the cut off
valves B in the valve box (see Figure 3). As the rocking levers m, m supporting the
rods, and reciprocating cylinder 7 and the rocking levers m³, m³ of the cut off
valves B are situated on the same cross shafts it follows that the motion given to the
said rods 1, is transmitted to the spindles of the said cut off valves B. At the ends
of the valve box A are adjustable stops q, q² against one or other of which, one or
other of the spindles B2 of the cut off valves B strikes just before the slide valve A³
has completed its stroke. Shortly before the spindle of the cut off valve strikes the
stop or the rod or which for the time being is locked to the advancing
cylinder by the tripping lever h, his released thereby causing the piston of that rod
to be forced into the said cylinder, thus compressing the spring p between the two
pistons n and n² as represented in the Drawing. When the hollow cylinder g in its
advancing motion has reached a position in which the plate i on the tripping lever,
which is out of gear, can engage behind the catch plate on the rod or the
engagement is effected by the action of the springs s, s on the cylinder g which springs
give the tripping lever 1, the required motion to effect the said engagement.
t
In any cut off after the half stroke of the piston, the jointed part 2 of the tripping
lever has to pass under the top end of the knock off lever d or e which it does by its
yielding power. Having passed the said knock off lever the spring brings the said
jointed part or arm into its normal position ready to act on its return motion. To
prevent shock in the hollow piston nor n² as it approaches the closed end of the
cylinder gan air cushion is provided. This air cushion is formed by the small
entrance valve t and adjustable exit valve u by the action of which valves air is readily
drawn into the space (see Figure 2) and permitted to escape by the valve u at any
desired rate. When the rod or 2 is released the said rod is arrested by the
cushioning of the piston n or n² against the end of the cylinder g. Hence the valve
spindle B2 of the cut off valve does not strike directly against the stop 7 or q² but is
arrested a short distance in front of the said stop. The slide valve A and cut off
valve B again move together and the spindle B2 strikes against the-stop 9 or q³ and
the motion of the cut off valve is arrested. After the cut off valve has thus been
arrested the slide valve advances upon the now stationary cut off valve for the purpose
of bringing the said slide valve into the proper position for the return stroke of the
main piston.
The action of the parts is as follows:―
In the drawing, the reciprocating cylinder g is advancing in the direction indicated
by the arrow in Figure 2, the rod being locked to the said advancing cylinder by
the tripping lever h, 2 and catch plates i, k and the rod at the opposite end of the
cylinder being out of gear with the tripping lever at that end. If the engine is
running at too high a speed the governor inclines the knock off lever d in a greater or
less degree from its normal position as illustrated in Figure 2. The result of this is
that as the reciprocating cylinder g advances in the direction of the arrow it strikes at
an early point in its stroke against the end of the knock off lever d thereby turning
the tripping lever h, on its centre and raising the catch plate i from the catch
plate and thus liberating the said tripping lever from the rod 1. The rod being
thus released its hollow piston n advances towards the right hand end of the hollow
cylinder by the pressure of the compressed spring p and the cut off valve B at the
right hand end of the steam chest coming into early action through the rocking
levers m and m³ and shaft m³ cuts off steam and thereby reduces the speed of the
engine. It will be understood that as the valve mechanism described moves in either
direction the tripping lever, at one end is liberated sooner or later according to
the speed of the engine acting through the governor or the position of the knock off
lever dor e while at the other end the tripping lever is being locked by the action of
the stop or catch mechanism described and represented.
When the speed of the engine is below the arranged normal speed the governor
inclines the knock off lever d from its normal position in a direction opposite to that
in which it is inclined when the speed of the engine is too high that is in a direction
opposite to that represented in the drawing. The opposite ends of the levers d, e, now

page_text: act upon the tripping levers and producing an action substantially the reverse of that
herein before described increase the speed of the engine.
Although I have represented the connection of the pistons and rods in the recipro-
cating cylinder with the tripping levers on the said cylinder by means of catch plates
yet I wish it to be understood that I do not limit myself to that arrangement as any
other arrangement of catching appliances for that purpose may be employed without
departing from the nature of my invention.
Having now particularly described and ascertained the nature of my invention and
the manner in which the same is to be performed I declare that I claim as my
invention of "Improvements in the cut off or expansion gear of steam and compressed
air engines."
First The combination with the slide valve of the steam or compressed air engine,
of the cut off valves described and represented, the spindles of the said cut off valves
being operated by rocking levers supported upon cross shafts, together with the
adjustable stops for the cut off valve spindles to strike against for the purpose and
substantially as herein before described and illustrated in the accompanying Drawing.
Secondly The combination with the cut off mechanism claimed in claim 1, or with
analogous cut off mechanism, of the regulating or timing mechanism described and
represented, the said regulating mechanism consisting essentially of a reciprocating
hollow cylinder carrying a tripping lever at each end and being provided with pistons
and piston rods pressed outwards or towards the ends of the hollow cylinder by a
coiled spring, together with locking appliances for locking the reciprocating hollow
cylinder at the proper times to one or other of the piston rods for the purpose and
substantially as herein before described and illustrated in the accompanying Drawing.
Thirdly Supporting the piston rods of the pistons in the reciprocating cylinder and
the said cylinder of the regulating mechanism upon rocking levers connected to cross
shafts, through which the rocking levers of the cut off valves in the valve box are
operated substantially as hereinbefore described and illustrated in the accompanying
Drawing.
Lastly The combination with the regulating mechanism of the cut off gear of the
connected knock off levers operated upon by the governor for operating upon the
tripping levers described and represented, the position of the knock off levers with
respect to the tripping levers determining the time at which the cut off valves shall
be brought into action substantially as herein before described and illustrated in the
accompanying Drawing.