IMPROVEMENTS IN MACHINERY FOR OBTAINING ROTARY MOTION."
Year: 1880

page_text: LETTERS PATENT to James Shepherd, of Coventry, in the County of Warwick,
Mechanical Engineer, for an Invention of "IMPROVEMENTS IN MACHINERY
FOR OBTAINING ROTARY MOTION."
PROVISIONAL SPECIFICATION left by the said James Shepherd at the Office
of the Commissioners of Patents on the 9th January 1880.
JAMES SHEPHERD, of Coventry, in the County of Warwick, Mechanical Engineer.
"IMPROVEMENTS IN MACHINERY FOR OBTAINING ROTARY MOTION."
The object of this Invention is to convert the reciprocating motion of the piston
of a motive power engine into a rotary motion.
To this end I give to what may be termed the steam cylinder of the engine the
form of a half cylinder, and I close the open side of this half cylinder by bolting
the same to a flat faced casting. The face of this casting I recess to receive a disc
which forms the termination of the engine shaft, and when in place stands flush
with the flat face of the casting.
This casting will constitute at once the bearing for the fly wheel or engine shaft
and the steam chest through which the shaft passes; and in this casting are also
formed the steam ways to the cylinder.
The piston is formed to correspond with the sectional form of the semi-cylinder,
one side being cut away to fit and work over the flat side thereof.
Across the flat side of the piston a groove is cut to receive a slide, into which
projects a crank pin standing out from the disc. The rod of the piston I set a little
excentric of the cylinder, and provide a stuffing box for it on one end of the
cylinder.
The steam chest is closed at its end by a cover, which forms an additional bearing
for the fly wheel shaft.
At the inner end of the steam chest the casting is recessed to receive a disc
valve which lies snugly therein, and is keyed to the fly wheel shaft which terminates
at its inner end, as before mentioned, in a disc fitted with a crank pin. Surrounding
the periphery of the valve is an annular recess formed in the casting, and communi-
cating with an exhaust pipe. An opening is made through this valve to admit
steam from the steam chest to the passages which lead to opposite ends of the
steam cylinder.
•

page_text: The inner face of this valve is also recessed to connect these passages alternately
with the annular recess before mentioned for the purpose of discharging the exhaust
steam.
It will now be understood that on steam being admitted through the rotation of
the valve to opposite sides of the piston alternately the piston will receive a
reciprocating motion, and through its connection with the crank pin it will impart
rotary motion to the disc, and consequently to the fly wheel shaft which carries it.
The rotary valve will supply steam alternately to opposite ends of the cylinder, and
at the same time open a passage for the escape of the exhaust steam.
It will be understood that any approved valve arrangement may be employed
for the purpose of obtaining a reversing motion or an adjustable expansion of the
steam.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said James Shepherd in the Great Seal Patent Office on the 9th July
1880.
JAMES SHEPHERD, of Coventry, in the County of Warwick, Mechanical Engineer.
"IMPROVEMENTS IN MACHINERY FOR OBTAINING ROTARY MOTION."
The object of this Invention is to convert the reciprocating motion of the piston
of a motive power engine into a rotary motion.
To this end I give to what may be termed the steam cylinder of the engine the
form of a half cylinder, and I close the open side of this half cylinder by bolting
the same to a flat face casting. The face of this casting I recess to receive a disc
which forms the termination of the engine or fly wheel shaft, and when in place
stands flush with the flat face of the casting.
This casting will constituto at once the bearing for the fly wheel or engine shaft
and the steam chest through which the shaft passes, and in this casting are also
formed the steam ways to the cylinder. The piston is formed to correspond
with the sectional form of the semi-cylinder, one side being cut away to fit and
work over the flat side thereof. Across the flat side of the piston at the middle of
its length a straight groove is cut to receive a slide, into which projects a crank pin
standing out from the disc, and by thus connecting the piston with the engine shaft
the reciprocating piston is caused to impart a rotary motion to the engine shaft.
In the accompanying Drawings I have shewn two arrangements of mechanism
for carrying out the principle of my Invention. In Sheet I. Fig. 1 shews in sectional
elevation and Fig. 2 in sectional plan a motive power engine in which the piston
and the fly wheel shaft are connected by a crank pin, as already explained, and
the steam is admitted to the cylinder by a disc valve keyed to the engine shaft
and seated in the steam chest; and Fig. 3 is an end elevation of the engine.
The other Figures on this Sheet will be referred to as the parts which they
specially illustrate are described. A is a steam semi-cylinder, fitted with a piston B

page_text: of corresponding cross sectional form; O is a casting, which forms at once a bearing
for the fly wheel or engine shaft D and the steam chest E, through which the shaft
passes. To the flat faced end of this casting the semi-cylinder A is bolted. F is a
disc, made fast to the end of the shaft D and fitting into a recess made for it in the
end face of the casting C.
Projecting from this disc is a crank pin f, which enters a brass slide b fitting a
transverse groove b¹ made in the flat face of the piston B. G is a disc valve keyed
to the shaft D, and serving to close the end of the steam chest E nearest to the
semi-cylinder. This valve is coned the breadth of its periphery, and against a
portion of this conical surface fits a coned metal packing ring G' carried by the
valve G. This packing ring closes the opening in the end wall of the steam
chamber, and it is so attached to the valve as to permit of its independent motion
that will allow of its automatic adjustment in the opening which it closes. The
uncovered part of the periphery of the disc valve G projects into an exhaust chamber
H, and in this chamber is the seat for the valve G. This seat is best seen in the
cross-section, Fig. 4, which represents also the form of the exhaust chamber, and
shews the steam passages e, e', which are covered by the valve. A segment shaped
passage g is made through the valve to correspond with these steam passages e, e¹,
which extend from the valve seat to the opposite ends of the semi-cylinder A, and
alternately conduct steam thereto, and lead the exhaust therefrom. This exhaust
steam is passed to the exhaust chamber H through a segmental shaped recess g'
formed in the periphery of the valve G, which recess as it comes into coincidence
with the exhaust passage provides for the escape of the exhaust steam into the
chamber. His an exit pipe from the exhaust chamber.
Figures 5 shew the valve G in cross section, and also in back view, it being
fitted with the metallic ring packing G'. By reference to these Figures the peculiar
construction of the rotary valve will be clearly understood.
The steam chest E is closed by a cover C³, which forms an additional bearing for
the fly wheel shaft.
It will now be understood that on steam being admitted through the rotation of
the valve G to the opposite sides of the piston alternately the piston B will receive
a reciprocating motion, and through its connection with the crank pin f of the disc
Fit will impart rotary motion to the disc, and consequently to the fly wheel shaft D
which carries it. The rotary valve G will supply steam alternately to opposite
ends of the semi-cylinder A, and at the same time open a passage for the escape of
the exhaust steam.
Figures 6 shew in front view and in cross section a form of adjustable slide which
I prefer to use for embracing the crank pin f. As the hole in this slide wears it
may be tightened up to fit the pin by simply screwing up the adjusting screws b²,
which will force the tightening wedges 6s further into the groove of the piston
face.
In Sheet II. I have shewn a modification of my improved mechanism for con-
verting reciprocating into rotary motion, the rotary valve serving in this case to
carry also the crank pin; Fig. 7 is a longitudinal vertical section, Fig. 8 is a sectional
plan, and Fig. 9 is a side elevation of a motive power engine illustrating this
modified forin of the Invention. In these Figures the same letters of reference are
used to indicate the like parts of Sheet I. Fig. 10 shews the recessed face of the
casting C, in which the disc valve carrying the crank pin is seated.
In place of an exhaust chamber as before the exhaust steam passes away directly
ly the exhaust passage H; e and e¹³ are the two stean passages which are in direct
communication with the steam chest E. Fig. 11 is a cross section of the casting C
taken through the exhaust passage H and the steain chest E. E' and H' are the
supply and exhaust pipes, their relative positions differing somewhat from the first
arrangement. The construction of the valve G is clearly shewn in the detached
views, Figures 12 to 15, Fig. 12 being a face view of the valve; Fig. 13, a back
view; Fig. 14, a cross section taken in the line 1, 2, of Fig. 12; and Fig. 15, a
Cross section taken in the line 3, 4, of the same Figure.

page_text: The face of this valve is recessed at g', but it does not extend quite up to the
periphery, as in the first example. This recess leads to an opening g³ through the
valve, and at the back of the valve an annular recess g³ is formed, which coincides
with the exhaust passage H, and maintains a communication between that passage
and the recess g³.
In order to maintain throughout the movements of the piston B the supply of
steam through the opening g to the semi-cylinder the face of the valve is recessed as
at g*, and the further to ensure this result the back of the valve is recessed at g**
to extend the communication between the steam chest and the opening g.
It will only be necessary further to say that as this valve takes the place of the
disc F, and carries the crank pin f, its face will work close to the flat side of the
piston, and it will supply the steam directly to the opposite ends of the semi-
cylinder, and open a passage to the exhaust steam to pass to the exhaust pipe in tho
manner already explained with reference to the first described arrangement.
The piston B is shewn as provided with a rod B', which may be employed to
steady the movements of the piston.
It will be understood that any approved valve arrangement may be employed
for the purpose of obtaining a reversing motion or an adjustable expansion of the
steam.
In some cases the Invention may be applied to the reciprocating piston of a
pump, which piston besides forcing air or water into any approved receptacle will
also transmit motion to a crank shaft, the rotary motion from which shaft inay be
utilized for driving machinory generally.
Having now set forth the nature of my Invention of " Improvements in Machinery
for Obtaining Rotary Motion," and explained the manner of carrying the same into
effect, I wish it to be understood that under the above in part recited Letters
Patent I claim,―
First. Connecting the reciprocating piston of a motive power engine with the fly
wheel shaft which carries the steam supply and exhaust valve by means of a crank
pin, in the manner and for the purpose above set forth.
Secondly. Combining with a flat faced reciprocating piston a crank shaft, in the
manner and for the purpose above set forth.
In witness whereof, I, the said James Shepherd, have hereunto set my
hand and seal the Eighth day of July, in the year of our Lord One
thousand eight hundred and eighty.
JAMES SHEPHERD. (LS.)