Improvements in or relating to the Valve Gear of Fluid Pressure Engines.
Year: 1896

page_text: PROVISIONAL SPECIFICATION.
Improvements in or relating to the Valve Gear of Fluid Pressure
Engines.
I, JOHN WILLIAM MELLING, of 82 Swinley Road, Wigan in the County of
Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:-
My invention consists in certain novel arrangements and combinations of parts
constituting an improved mechanism for operating the expansion gear of engines
fitted say with Cornish or double beat valves or it may be with other kinds of
valves. In the Specification forming part of Letters Patent No. 4920 of 1888
granted to me an arrangement for working the tripping gear of winding or other
reversing engines is shown and described and my invention relates to that
arrangement but according to my present improvements I control the movement
of the tripping catches which regulate the closing of the valves by means of a
double cam for each engine centred ou a suitably guided sliding piece to which
is given a reciprocating movement from any convenient part of the engine; the
positions of the cams on the sliding pieces are determined by a governor and
also at pleasure by the engine man as described in the before named patent.
The cams are so shaped that when the engines are running slowly and the governor
is down they are drawn to one extremity of their movement so that they do not
touch the levers through which the tripping catches are tripped, but when the
speed of the engines is so great as to cause the governor to rise to its full height
the full parts of the cams at a very early stage of the reciprocating movement
are brought into contact with the levers and through connections the tripping
catches are disconnected from the valve spindle lifters or bridles and the valves
are allowed to fall and close at their carliest stage. The intermediate points of
cut off are determined by the position in which the governor holds the cams.
In the case of a winding engine the action of the cut off gear is intended to
be as follows:-
At the commencement of the wind when the movement is slow and the governor
is down the cams are drawn into the position in which their narrow parts are in
line with the levers to which the tripping catches are connected and when in this
position their reciprocating movement is not sufficient to bring them into contact
with the levers, consequently the valves are not tripped but are raised and lowered
by the rocking levers or their equivalents in the ordinary way and steam is
admitted to nearly the full stroke of the pistons. When the speed of the engines
has increased to the rate at which the governor begins to rise and alter the position
of the cams and draw their fuller parts in line with the levers any additional
increase of speed causes the governor to rise higher and thereby draw the cams
so that they strike the levers at earlier stages of their movement and so through
their connections the valves are tripped and closed at stage of the stroke which
corresponds with the position in which the governor holds the cams. In the con-
nection between the governor and the cams is placed a lever one end of which is
connected to the governer and the other is, fulcrumed in a block or lever the
position of which is controlled by the engine man. The rod from the cam is

page_text: connected to this lever so that at any time if the engine man desires to alter the
action of the governor on the position of the cams he can do so by changing the
position of the fulcrum block or lever.
My improved valve gear can be applied either to single or double valve boxes
or to operate the trip catches whether carried in the lifters or in the bridles of the
valve spindles or to the catches of slide or other valve trip gear, or to the valve
gear of ordinary turning engines.
The reciprocating movement is given to the cams by preference through the
sliding pieces by means of levers and these levers are fixed on rocking shafts the
movements of which synchronize with the movements of the pistons.
The levers on which the cams operate are connected by springs which return
them and through their connections the tripping catches into the right positions
for the next effective movement of the valves.
The cams may be carried either in a horizontal or vertical position or they may
be substituted by wedge shaped pieces fitted on the levers and moved by connections
from the governor.
Dated this 17th day of March 1806
H. B. BARLOW & GILLETT,
Agents for Applicant.
LEIE
Improvements in or relating to the Valve Gear of Fluid Pressure
Engines.
I, JOHN WILLIAM MELLING, of 82 Swinley Road, Wigan in the County of
Lancaster, 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 cousists in certain novel arrangements and combinations of parts
constituting an improved mechanism for operating the expansion gear of engines
fitted say with Cornish or double beat valves or it may be with other kinds of
valves. In the Specification forming part of Letters Patent No. 4920 of 1888
granted to me an arrangement for working the tripping gear of winding or other
engines is shown and described and my invention relates to that arrangement.
In the accompanying four sheets of drawings-
Fig. 1 is a side elevation of part of a winding or reversing engine to which my
improved mechanism for operating the valve gear is applied, Fig. 2 is a plan view
of part of Fig. 1 and Fig. 3 is an end view on the line A B, Fig. 1, partly in
section.
Figs. 4, 5 and 6 are similar views to Figs. 1, 2 and 3 showing another arrangement
of mechanism for operating the valve gear.
a designates a stationary part of the engine frame, b the valve chest which
contains the admission and exhaust valves, c the admission valve spindle and d the
exhaust valve spindle, e is the lever or tappet secured on the rocking shaft f
for actuating the valves and valve spindles c and d; all the above parts are of the
ordinary construction; the admission valve and spindle c' shown at the other end
of the cylinder is actuated by the rocking shaft to which is secured a tappet g
for raising the lifting piece h.
To actuate the expansion gear I employ in Figs. 1, 2 and 3 a double cam i
mounted on a stud secured into a sliding piece; to which is given a reciprocating
movement by the eccentric or other shaft, not shown, coupled to a pink on a lever k¹
secured to a shaft to which is secured a lever the end of which fits into a

page_text: recess made to receive it in the lower part of the sliding piece; the position of
the cam i on the sliding piece is determined by the governor and also at pleasure
by the engineman by connections to a lever l as shown in Fig. 2, and as described
in the before mentioned patent. The cam i is so shaped that when the engine is
running slowly and the governor is down the cam is drawn to one extremity of
its movement so that it does not touch either of two levers m m pivoted to a
stationary frame and drawn together by a spring m'; the first of these levers is
connected by a rod n to a tripping or catch lever o pivoted to a bridle on the
valve spindle cat o; the lever m' is similarly connected by a rod n¹ to a tripping
or catch lever o' pivoted to the lifting piece h at o³.
When the speed of the engine increases so much that the governor rises to its
full height it draws the lever in the direction shown by the arrow in Fig. 2,
until the full parts of the cam at a very early stage of the reciprocating movement
are brought into contact with the levers m m¹ which by their connections disengage
their tripping catches o o' from the lever e or bridle on the spindle c' and so
allow the valve spindles ce¹ to fall and close the valves at their earliest stage.
The intermediate points of cut off are determined by the position in which the
governor holds the cam i.
In Figs. 4, 5 and 6 a wedge shaped piece p is employed in place of the double
cam i; this wedge is fitted to slide upon a lever q secured to a short,shaft q' to
which is also secured a lever q³ which receives an oscillating movement by means
of an eccentric shaft or from any convenient moving part of the engine; the
wedge piece p is held in position on the lever q by a link connected to the wedge
by a pin and pivoted at its other end to a lever a fulcrumed on a shaft sto
which is also secured a lever connected by rods or equivalents to the governor,
not shown. The valve spindles cc and d, levers m m¹ and rods n n' connected to
the trip catches o o' are substantially the same as shown in Figs. 1, 2 and 3.
The wedge piece p fitted on the lever 9 and connected to the lever so long
as the governor is down and the engine is running slowly remains so low that
although oscillating with the lever q it does not touch the pivoted levers m m
which are drawn together by a spring m but as the speed of the engine increases
the lever will be drawn in the direction of the arrow, Fig. 4, whereby the link r
and wedge p are raised until gradually the wedge acts upon the curved ends of
the levers m m and by the connecting rods n n¹ release the catch levers o o' from
the rocking leverse which lift the valve spindles c and the valves are thereby allowed
to fall and close.
Although no connection from the engineman to the levers is shown it is obvious
that such a connection such as the lever Fig. 2, could be applied to enable the
engineman to govern the trip gear when required.
In reversing engines the reciprocating movement is given to the cam i or wedge
piece p so as to synchronize with the movements of the piston; in non-reversing
engines the movement of the cam i or wedge piece p might be varied from that
position.
My improved valve gear can be applied either to single or double valve boxes
or to operate the trip catches whether carried in the lifters or in the bridles of the
valve spindles or to the catches of slide or other valve trip gear, or to the valve
gear of ordinary turning engines.
I have shown and described my improvements as applied to winding or reversing
engines but I wish it to be understood that they can be applied to other fluid
pressure engines in which case there might be no need of a connection from the
valve gear to the engineman.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. A double cam mounted between a pair of pivoted levers or their equivalents
connected to the trip gear of the adinission valves the cam receiving a constant

page_text: oscillating movement and its position being controlled either automatically from
the governor or by hand or by both so as to vary the time of cut off substantially
in the manner and for the purposes herein described with reference to Figs. 1, 2
and 3 of the drawings annexed.
2. A double wedge mounted and free to slide upon an oscillating lever placed
between a pair of pivoted levers or their equivalents connected to the trip gear and
admission valves, in combination with connections for moving the double wedge
automatically from the governor or by hand or by both so as to vary the time of
cut off of the valves substantially in the manner and for the purposes herein
described with reference to Figs. 4, 5 and 6 of the drawings annexed.
Dated this 17th day of December 1896.
H. B. BARLOW & GILLETT,
17 St. Ann's Square, Manchester, Agents for Applicant.