Mathematical Working Model for Valve Motions of Steam Engines and others Motors, with Special Cabinet.
Year: 1895

page_text: Date of Application, 17th Aug., 1895
Complete Specification Left, 18th May, 1896-Accepted, 17th Aug.,
1896
PROVISIONAL SPECIFICATION.
Mathematical Working Model for Valve Motions of Steam Engines
and others Motors, with Special Cabinet.
THOMAS GREENWOOD, Mechanical Engineer, 33 Brompton Street Cheetham
Manchester in the County of Lancashire. I THOMAS GREENWOOD do hereby
declare the nature of this invention to be as follows:-
My invention relates to improvements in what is known as a working model for
showing the action of valves, and valve motions for steam engines; such that my
improved arrangement will make it a combined working model and mathematical
instrument which with other improvements will be shown to have very much
increased its value, both for instructions and designing valves and valve motions
for steam engines, gas engines and other motors, and as there will necessarily be
quite a number of portable parts, a suitable cabinet has been constructed for the
same.
The following is a description also showing the construction of separate parts of
this invention.
The main frame as foundation may be made of either wood, metal, or other
suitable material.
0
On a short spindle representing the crank shaft is fixed a crank, ajustable to any
required length of stroke, and also answers as an index pointer. At the back of
the crank and on the same spindle are two ajustable pointers, which represent two
cranks as excentrics; which cranks are also ajustable to any required length of
stroke, and can be set to any angle with the main crank.
The main frame plate bracket with bearing for the above spindle is located
between the two crank excentrics and the main crank; and may also be arranged
for the main crank at the back, with an index pointer representing it at the front,
and fixed to the same spindle so as to revolve with the crank; also the above two
cranks as excentrics with their two ajustable pointers may be in front.
There is also a fender bracket arm which may be fixed at either front, or back;
which is for a bearing for the short spindle, for one of the excentric cranks on the
outside, and with a lever with slott as driver on the inside, so that this crank
receives its motion from the crank excentric on the same spindle as the main
crank; the crank pin of the excentric is the driver which gives the motion to the
above slotted lever. The above two short spindles are in the same centre line aud
represent the crank shaft. There are several valve motions that can be better
shown with the two crank excentrics in front; and the pointer representing the
main crank may be used for giving the required motions. The movable valve
sections; cylinder ports; rotary index fixed central with crank shaft; lineal
index representing both piston and valve stroks; and the proportion lever pointer
will all be shown at the same view as the end of crank shaft. The above rotary or
circular index inay have divisions for both 360 degrees and 400 divisions; and
double so as to be read either way: and for the purpose of calculation of cource
each degree is suposed to be divided into 60 or 21600 whereas the 400 is only
divided into 10 or 4000 which will simplify the calculation and for which the
author or inventor has got out a table showing the corresponding arc to versed
sine; besides this working model is so constructed that it will automatically find
the corresponding arc or degrees to any given versed sine or vice versa. This rotary

page_text: .
the valve sections.
with the 'Crank shaft so as to be read by the same view as
This working model has also a piston or lineal index with 100 main divisions for
any suitable length; with each divided into two, such that by the following new
proportion lever index pointer any centage of any length of either piston or valve
stroke can be automatically ascertained also the versed sine for any length as
radius unity and its corresponding arc or degrees as stated above.
This index will also be double, so as to be read from either end, and with long
division lines such that the end of lever pointer does not leave them as the pointer
moves in a circular direction.
The main plate is constructed so that the parts with piston, and valve slides, and
sections, lineal index, and the proportion lever pointer; can all be ajusted to any
required distance from centre of crank shaft; by suitable brackets and slide rods
according to the length of connecting or excentric rods; which are also ajustable
to any length required. On this saine plate as lineal index: there is a slott, at
right angles and central to it, can also be ajusted central with the piston and valve
stroke; which slott is for fixing an ajustable stud, as the centre or fulcrum for the
proportion lever pointer to work on; which pointer has also a long slott in its
middle part, in which is fitted an ajustable bush with lock nut on, so as to be set to
any position required, and so as to have a free motion on the above stud as a
centre.
This lever index pointer has also a pin or stud at the opposite end to the
index end; which fits in a suitable slott which represents either centre of piston or
the slide valve: so that any required length of stroke can be set at one end of this
lever and the pointer end set to the exact length of the lineal index. That also
by this arrangement having the connecting rod geared to piston as crosshead; also
geared to crank; will show the exact difference caused by the angularity of
connecting rod also for excentric rods with valve travel.
Just as the same circle or rotary index of 400 divisions or 360, is of course the
same for all sizes of circles: so is this lineal index adapted for any length of stroke,
by the action of this new proportion lineal index pointer; it not only gives the
centages of any length of stroke with its corresponding part of the rotary index :
but also gives the corresponding arc or degrees to versed sine; and vice versa by a
suitable connecting rod with slott at right angles for crank pin to work in; besides
taking into account the différence caused by the angularity of connecting and
excentric rods used at the time. This combined action making a new mathematical
instrument of considerable ralue to engineers; as it automatically furnishes very
important factors of certain calculations; and also furnishes highly interesting
means of testing the accuracy or otherwise of the calculations; which will very
much increase its value as a working model; for giving instructions; designing;
and for calculations regarding slide valves for steam engines and other motors as it
accurately locates the valve action in regard to crank or piston at any given time.
The application of this combined working model will be shown by rules in book
form by the author or inventor.
:
It is also constructed with Stephenson's; Gooches; and Allens link motions;
besides Joys and other radial valve motions such that this most difficult subject to
young engineers will be made as easey to understand as it seems possible; as the
subjects treated on are not only made highly interesting; but also at once furnish
the means of testing doubtful ideas which quickly result in real knowledge of
considerable value to the engineer.
A suitable number of curved links will be provided: each link made so that it
'can be used for any length of valve travel having the same radius or curve; and
each link made so that the excentric rods can be geared suitable to the length of
valve travel being used at the time; and so that the excentric rods can be geared
at either the ends or sides of the links; and the radius stampted on each link.
There will also be a good number of special cards in section, both for showing the
cylinder ports, and slide valves; and the expansion valves working with the inain

page_text: valve; also a large number of special indicator cards so that slide valves can be
geared up to show the action, and parts in each, that corrispond; so that both
when in error, and best results can be pointed out.
The construction of cabinet suitable for containing the above parts of the
working model is as follows. The bottom drawer is round, near one edge of which
is fixed a vertical spindle which is attached to one edge of round shaped drawers
above, so that by an excentric horriztal motion on the above spindle, the drawers
are opened and closed. On the outer edge of the bottom drawer opposite to the
virtical spindle, is fixed a light pillar bracket casting, the top part of which is
fixed to the cover, of the top excentric drawer, the opposite edge of this cover, is
fixed to the top of the above spindle. A lock is fixed at the back of the pillar
bracket; and on the edge of each of two excentric drawers is fixel a small bracket
with knob for opening and closing the drawers, also with eye so that the same bolt
of the lock shoots into both eyes such that the three drawers are locked with one
lock, and the top of this pillar bracket also forms an automatic date setting
arrangement, by five virtical wood spindles by means of a disc and two tapes.
The sides of the above round drawers are all turned out of one and the same piece
of wood of a suitable thickness also a round partition on the above cover with
excentric lid & vase such that the waste is reduced to a minimum; also the cost;
while at the same time furnishing a number of suitable partitions for the extra
parts as required for the above mathematical working model as specified.
Dated this 15th day of August 1895.
Mathematical Working Model for Valve Motions of Steam Engines
and other Motors, with Special Cabinet.
1 THOMAS GREENWOOD of 33 Brompton Street Manchester in the County of
Lancashire 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 :—
My invention relates to improvements in what is known as a working model
for showing the action of valves and valve motions for steam engines.
For showing the great varity of valve gears or motions which gives the motion
to the slide valve, I have constructed a combined or compound bracket which can
be quickly adjusted longitudinally on the main bed plate, and which is universal
in its' application for readily showing the above valve gears, and for also showing
the difference caused by useing a rock shaft for the valve motions; these mctions
are readily got from the quadrant plate which forms a part of the above compound
bracket, the two arms of this quadrant plate, which has slots in, to work freely on
a screw stud as centre, which represents the rock shaft, and the above two arms
adjusting levers on the shaft. I also construct a main bracket with vertical
epindle representing the crank shaft so as to have three or more cranks or
excentrics which can be set to any angle to each other, and each with their dial
I also
pointers, and with either one or two circular dial plates for the same.
construct a saddle bracket to slide on the main bed plate so as to be quickly set to
any required distance from the centre representing the crank shaft; with a fixed
bracket on the above saddle, with bearings for three or more spindles which
represent the piston rod and valve spindles, with adjustable arms fixed to the
above rod and spindles, for attaching valve sections to, such that one or more
cylinder port sections can be quickly adjusted to the working valve sections also
for showing the ordinary expansion valve in motion on the back of the ordinary
slide valve. I have constructed bars with spring clips for quickly adjusting and

page_text: fixing valve and cylinder port sections on. I also construct an ajustable bracket
with bearings for a valve spindle so as to be used for a varity of valve gears; with
an adjustable arm for transfering the motion to one of the other valve spindles
which has the arm with the other valve sections on. I also fix on the above
saddle bracket, the bracket for a proportion lever. I also construct an adjustable
anchor bracket so to be set and fixed in any required position on the main bed
plate.
I construct a proportion lever to work in combination with this model when
required; this lever has a pointer which moves. over a lineal index, which can be
set to ascertain the average port opening to steam for any part of the pistons
stroke, and also ascertains the average port opening to exhaust. In each case the
exact number of centages open will be indicated by the above proportion lever;
say at every twentyeth part of the pistons stroke up to the point of cut off, and
also every twentyeth part of the stroke during the time that exhaust is taking
place. The above lever can also be quickly geared with any length of pistons
stroke, and of course with any length of connecting rod, with the pointer of the
lever set to move exactly the length of the lineal index, which pointer moves
simultainously in combination with the crank pointer over either of the two
circular dials with the 360 degrees and 400 divisions on, and enables points of
cut off to be either located on the circular index or dial, or on a straight strip of
card fixed, and marked from the centre line of piston, and also indicates the
difference caused by the angularity of the connecting rod. It is also arranged
for getting natural versed sign both for 360 degrees and 400 divisions, as on the
circular dials, which lever will be found to be a useful mathematical combination
to this working model; which is also constructed so that all important parts can
be seen at one and the same view, such that a great number of engravings can be
easily and cleaply got out to be used in book form for giving instructions on this
working model. I have also constructed it so that it is universal in its' application
to the slide valve, the great varity of valve motions for both simple direct
action with one cylinder and triple expansion with or without the reversing
motions such that all the above named parts working in combination is a very
great improvenient, and forms a very compact and new commercial article. I also
construct a cabinet for the above further particulars of which will be shown by the
drawings and description as follows.
It will be noticed in the drawings that in some cases the plans and elevations are
only given in part. Fig. 5 is a front view and part elevation of Fig. 4 for showing
more clearly a few of the similar parts as shown by similar letters; the two parts
at the top of Fig. 5 are elevations of four similar parts mark V on Fig. 3.
Also Fig. 2 as an end elevation clearly showing the parts is a more complete form;
but Fig. 1 is only shown in part plan; in each case the similar parts have similar
letters also the letters on Fig. 10 Sheet two are similar parts to the similar letters
on Fig. 3 Sheet one.
DESCRIPTION OF DRAWINGS.
Fig. 1 is a part of the main bracket which forms the bearings representing the
crank shaft with circular index.
Fig. 2 is an end elevation of Fig. 1. A. A' represent the crank shaft.
B. cranks or excentric arms which have adjustable slots same
as shown
at C. Fig. 24. Care adjustable links same as C. to which ends of connecting
and excentric rods are fitted by a short peg in rod ends, and fixed by a milled
head screw; the peg to slide in the slot. D. is both crank pin and handle for
giving all the motions. E are the three dial pointers, the one with notches on
each side of the hole as shown by Fig. 26 fits on ends of a pin fixed in the spindle
close to the index plate F. The friction dial which is next to the above, and is
cut out at one side, and with a projection at one side to set it by as shown by
Fig. 25. G are two screws for taking up the end
fixing the arms when set to the required angle play. H are two screws for
is a portable fender bracket

page_text: which is nxed by the two screws J on the top or the main bracket which 13
fixed to the main bed plate L. The arm or lever M is for transmitting the motion
from the bottom crank spindle to the top one, by means of the crank pin or stud N.
The cranked connecting or excentric rod O is so that it can be geared to reversing
links on the same level or plane as the excentric rod P and when geared for
shewing the motions of the ordinary expansion valve working on the back of the
other valve; of course a straight excentric rod must be used as shewn in dotted
lines. Qis a square block with two holes on each side as shewn by the dotted
lines, the same centres as the holes in the bed plate.
Fig. 3 is a plan of parts as follows. A is saddle bracket. B is the bracket for
piston rod and valve spindles. C is the main connecting rod. D are the cross
heads. E is the piston rod. F are valve spindles. G is an adjustable bracket
with bearings for valve spindles. H are two milled head nuts fitted on T head
bolts which slide in the slot I. J is an arm for transmitting motion to the valve.
W is a screw for fixing this urm in the position required. Fig. 10 Sheet 2 shows
an end elevation of the above bracket. G and arm J. K are arms for adjusting
and fixing the bar or bars with the cylinder port sections on. L is the above bar.
M the port sections. N is an adjustable arm attached to the valve spindle F, and
also attached to the movable bar O, on which is fixed a valve section, by milled
head screws and spring clips as shown at the top of Fig. 5, and which are shown on
the bar with the cylinder port sections on. The bar P is for expansion valve sections
as working on the back of the ordinary valve for which the adjustable arm is
shown in Fig. 4. Sheet 2. R are milled head nuts on eye bolts as shown by Fig. 27
for adjusting and fixing the arms N. S. is a milled head screw for fixing the saddle A
the required distance from the centre of the crank shaft on the bed plate L.
T are two screws for fixing the bar with port sections on. Fig. 7. and Fig. 11.
are two elevations, one is an anchor link of Joys valve motion. The other a
compound or combined bracket of which the plan shown in Fig. 6 consisting of
an angle bracket with two slots at right angles, which is fixed to the bed plate in
various positions as required, on which is a quadrant with two arms at right angles
with the centre of quadrant, with long slot in each arm, also on this quadrant is
fixed the straight or curved links, with block nuts to slide in the curved slot of the
links, also in the long transverse slot of the angle bracket, the block nuts are made
to have a free sliding motion when fixed to the parts above, by having that part of
the nut which fits in the slot slightly longer than the depth of the slot, and the
same nut may be used for fixing the parts above when required to be stationery,
by placing a thin washer between the nut and the under side of the plate. In the
same way the screws which are used as centres for other parts to revolve on, may
be either fixed on so as to work freely by having the plain part of the stud screw
from the under side of the head to shoulder longer or shorter. It will be found
that this compound bracket is universal in its adaptation for nearly all kinds of
valve motions, 10 is an angle bracket. 11 is the quadrant bracket. 12 is a block
nut. 13 a washer. 14 is a screw with shoulder to nip against the washer so as to
leave the quadrant free to revolve on it as a centre. 15 is a block which two
screws 16 pass through so as to fix the curved link 17 to it. 18 is a distance collar
or washer which has a hole for screw to pass through into block out 19 so that
when fixed it will slide freely in the curved slot 20, and as the milled screw 21 has
a plain part the shoulder of which comes against the face of the collar so that the
valve lever 22 can move freely on it as a fulcrum. 23 is a valve connecting rod.
24 is a milled screw for the joint at the end of valve lever. Fig. 3. G' is a link
by means of which the port opening to steam may be adjusted according to the
distance between the centres on the connecting rod, and end of valve lever. He is
an anchor link working on the centre I° as shown at Fig. 11. The four screws 28
in Fig. 7 and J Fig. 11 are for fixing the angle brackets to the bed plate.
Fig. 15 is Allens straight link which can be fixed on the block 15 for showing one
of Hackworth's valve motions; which is got from the excentric rod when working
at right angles to the centre line of engine. Allens link motion can also be shown.

page_text: Also the harmonic motion and at the same fixing also answers for getting natural
versed sine in connection with the proportion lever and its lineal index. Fig. 13
is a link for Stephenson's link motion. Fig. 14 is an elevation showing two milled
head screws 32. for gearing ends of excentric rods to. 33 is an angle bracket that
can be fixed to any of the links including the link 17. in Fig. 6 which is shewn
geared up with Joys valve motion, and is arranged for gearing excentric rods to
either side of the link so as to be used for Stephensons, Gooches, and others.
Fig. 16 34 is for end of drag link, 35 is the end view of the curved links. The
other end of drag link to be attached to one of the arms of the quadrant with
the compound bracket Fig. 6 and 7. fixed on the block Q' which block is shown
at Fig. 2. and when fixed on the block in the position shown, Hackworths;
Marshalls; Bremmels Swans, and other motions can all readily be got with a few
additional links screws and valve connecting rods.
X as shown in Fig. 3 and 4 is a bracket with slot for an adjusting stul as
fulcrum and centre of the proportion lever. Y are screws for adjusting this
bracket in a vertical direction.
Z has the lineal index on the top side with which it can be slided out to any
distance when a longer dial pointer is being used. A¹ is a milled part of the stud
collar for quickly adjusting the stud. B³ is the collar of a bush which fits on the
stud with screw thread on the outer part suitable for the milled nut C³ so as to be
fixed to any part of the slot as shown in the proportion lever marked D.
E' is a
stud finger the same diam. as the slots in N and has a sliding motion equal to its
versed sine, and as the versed sine of the dial point at the other end will always
be in the same ratio it will not effect the accuracy of the proportion or centages
got by it, by taking off the nut C³ the dial or lever D₁ can be turned over so as to
gear with the part N above. F is the lineal index which has 10 divisions
representing 100 with each divided so that half will represent 100 so as to get
natural versed sine from either the 360 degrees or the 100 divisions. The fulcrum
of the above lever can be quickly set to any maximum port opening to steam say
a motion of half inch plus the lead while the pointer at the other end moveз
exactly the full length of the index, starting at dead centres. The centages of
valve opening to be noted down say at periods of one twentyths of the piston
stroke which will be seen by a pointer set on the part representing the piston,
with the twenty divisions fixed on the same part as the bar with the cylinder port
sections on. This column of centages will show the width of port opening for
each period from dead centres to the point of cut off.
The same arrangement will also show the centages of exhaust opening and
accurately show the distortions or otherwise as takes place at every part of the
piston stroke. This enables comparrisons to be made with all valve notions which
will doubtless be very interesting to engineering students.
The dial end of the proportion lever cau of course be extended so as to get the
minimum of motion that may be required for port opening while the pointer end
moves exactly. the length of the lineal index.
Fig. 19 and 20, a plan and elevation is a lap plus lead lever. The part 37 is
for adjusting the lap plus lead. 38 is the fulcrum. Kirks, Mortons, Bryce
Douglas Thoms's and other valve motions can be got with this lever in connection
with the parts of the compound bracket.
The above compound bracket is also used for Walsschaerts valve motions. In
this case the quadrant bas.a rocking motion on its centre by one of the excentric
rods.
Fig. 8 and 21 is the plan and elevation of an arrangement for having the circular
index with the three dial pointers so that in all cases they can be clearly seen.
The parts A B K¹ & are the same as A, B, K & F in Fig. 2. One wheel
is fixed on the crank spindle, one is a carrier wheel and the other is fixed on the
dial spindle, the pitch line of wheels is shown in dotted lines on the plan; as shown
all the motions can be gut by the handle as fixed on the under side of the gear
wheel, but the handle as shown on the other part is preferable so that only very

page_text: light wheels need be used for moving the dial pointers. The one nearest to the
dial plate is fixed to the spindle by a pin as shown. The other two to be friction.
dials located above on the same spindle with a small milled nut and washer to bear-
against the face of the top dial they can be quickly set by having their respective
cranks set at dead centres. It will be seen at once that this working model is not
only universal in its application for showing and testing the actions of slide valves
and valve motions; but also clearly shows by a plan view the exact positions of
the piston and crank, the excentrics, valves, and all other parts of the motions
and as there is no limit to the number of interesting motions that can be set on it..
It will be of considerable value for designing, giving instruction to students and
for engineering periodicals by the cheap process of getting the engravings by
photography. The plan view shows all that will be required in a minimum of
space.
It will be seen that the three cranks may be used as ordinary excentrics and as.
working direct with three valve sections and that three sections of cylinder ports.
can also be set in position and by the double dial plate the angles of all the
excentrics and cranks can be accurately ascertained and located, in this case the
pin to be taken out of the dial spindle so that all the three dial pointers can be
set by friction.
In the case of marine engines the link motions can be set seperately or all may
be geared up by repeating the fender bracket I in Fig. 2.
The circular index as shown on Fig. 1 & Fig. 8 to have divisions on the inner
circle of 360 degrees and 400 divisions on the outer circle. As the whole or parts
of the later divisions remain simple decimals; it makes the calculations regarding
the circle very much simpler as less figures are required which as a rule will give
mor accurate results and answer much better for the purposes required by the
engineer.
Fig. 9 Fig. 28, 22 and 23 is a plan and elevation of cabinet which may be made
in various sizes.
Fig. 20 39 are three round shaped partitions or drawers. The two top ones
open by an excentric motion swinging on the fixed spindle 40 in Fig. 9 as shown
open by the plan Fig. 28. 41 in Fig. 9 is pillar bracket of which two views are
given for the purpose of more clearly showing the construction. 42 is the lock
the bolt of which shoots in a vertical direction so as to pass through both the
eys 43 in Fig. 20 when the drawers are closed. One of these eys with knob is
fixed flush with the under side of the top partition & the other is fixed on the top
edge of the middle partition. 44 Fig. 9 is a bracket for fixing the spindle bolt in
with nut at the bottom and a small screw at the side. 45 is a lid with 5 holes in
as bearings for the wood spindles which are the same centres as shown by 46 and
is fixed to it by a screw on each side and also fixed to the back part of the pillar
bracket by two screws. The projections of the bottom part of Fig. 23 is fixed to
one edge of the cover 47. 48 are two wood spindles to which is attached the ends
of a tape with the names of the months on, the tape to pass in front of a virtical
projection a little higher than the width of two tapes. 49 are for the tape with
numbers on up to 31 which is in the middle position. 50 is a disc with the day of
the week on the periphery and located at the top. Fig. 22 forms a part of the
eame to be fixed on 47 Fig. 9. The vase and the sides of the four partitions are
all turned out of one and the same piece of wood or may be turned out of sections
glued together.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is :-
1. The cabinet as shown and described.
2. The proportion lever as shown and described in Fig. 3 and 4.
1

page_text: 4. The combined arrangement of bracket B with saddle and bracket G and
with transfer arm J also the arrangement for the transfer arm N with the bars for
showing the cylinder port and slide valve sections.
5. The compound universal bracket as shown in Fig. 6 & 7 for showing various
valve motions.
Dated this Sixteenth day of May 1896.
THOMAS GREENWOOD,
33 Brompton Street, Cheetham, Manchester.