Year: 1888

page_text: Date of Application, 15th Feb., 1888
Complete Specification Left, 12th Nov., 1888
Complete Specification Accepted, 14th Dec., 1888
I, HORACE MUNCASTER, of St. Georges, Wellington, in the county of Salop,
Mechanical Engineer do hereby declare the nature of this invention to be as
follows:-
:-
My invention relates to improved apparatus for automatically varying the cut-off
of steam and other engines.
According to my invention the cut-off or expansion valve is operated by an eccentric
upon the crank shaft or an auxiliary shaft driven from the crank shaft, through the
medium of suitable rods and levers. The eccentric itself works in a strap in one end
of a pivotted lever (hereinafter termed the eccentric lever) and causes the oscillation
thereof, the amplitude of which oscillations and consequently the extent to which the
valves open being varied according to the position of the pivot. The motion of the
eccentric lever is transmitted to a rock shaft having cams thereon which cams work
within a stirrup upon the valve rod and alternately move. the valve.
In order to enable the pivot of the eccentric lever to be automatically adjusted as
required, the said pivot is carried upon one end of a bar the other end of which is
jointed to a moveable link, connected at one end to a guide lever and at the other
to a lever directly operated by the centrifugal governor of the engine, so that as the
governor lever is moved the link is also moved and with it the bar carrying the
said pivot.
It is obvious that two or more sets of cams may be arranged upon the rock shaft
according to the number of steam valves with which the engine is provided.
Dated the 15th day of February 1888
•
G. F. REDFERN & Co.,
4, South Street, Finsbury, London,
Agents for the Applicant.

page_text: HORACE MUNCASTER Mechanical Engineer St. Georges Wellington Salop 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:
The Invention relates to cut-off or variable expansion mechanism for engines
operated by steam or other expansive fluid and its object is chiefly to provide improved
automatic mechanism controlled by any ordinary centrifugal governor and which is
applicable to existing engines already provided with common slide valves or other
forms of distribution valves.
The Invention may be described by the aid of the accompanying drawings
Figure 1 is an elevation part in section.
Figure 2 is a plan and
Figure 3 an end view of portion of the mechanism arranged according to this
Invention.
a is the crank shaft of an engine or an auxilliary shaft revolving at the same
angular velocity as the crank shaft and is a suitable governor of any type and
operated in a suitable manner.
c is the chest in which works the ordinary valve and d is the cut-off valve the
inner cylindrical portion of which is actuated by the mechanism herein described the
said cylinder being provided with several annular openings e corresponding with
suitable openings in the outer case and which according to the position of the valve
are all open or all entirely closed.
fis an excentric which is secured to the shaft a and g is the excentric strap which
works on the excentric is a lever connected to the excentric strap at one end and
which at the other end is connected to one end of the rod i the other end of which
extends to the cut-off valve. This lever his pivotted at j so that as the excentric
rotates a reciprocating motion will be imparted to the rod i and thus communicated
to the valve d.
In order that the position of the valve may be adjusted to the variations of the
governors the pivot j is carried at one end of the links k k the other end of which is
attached at to the double link in the extremities of which are connected to the two
levers no which are arranged in such proportions as to guide the point in a path
curved approximately to the arc of a circle by the movement of the lever o which is in
engagement with the governors.
By the lifting of the governors the linkwork is made to assume the position
indicated by the dotted lines and varying the angle of the links k k and thereby
varying the amplitude of the oscellations of the lever h and also the travel of the
valve d.
37
It is obvious that the mechanism herein before described may be employed to
actuate a slide valve of the ordinary construction or lift valves of the "Cornish
type in the latter case however suitable bell crank levers must be employed.

page_text: Having now particularly described and ascertained the nature of my said Inven-
tion and in what manner the same is to be performed 1 declare that what I
claim is:
(1) The novel arrangement of expansion gear or automatic cut-off mechanism
characterised by the employment of a lever in conjunction with an excentric at one
end and connected at the other end to the cut off valve the said lever working
upon a pivot or fulcrum adapted to be moved through the medium of the links k k
the link m and the levers no the latter being directly operated by the governor.
(2) The employment for this purpose the hollow cylindrical valve d provided with
several annular openings so arranged as to be all open or all shut according to the
position of the inner portion of the valve.
Dated this 8th day of Novawhn- 1000