Improvements in Trip Expansion Gear for Steam Engines.
Year: 1891

page_text: Date of Application, 3rd Nov., 1891
Complete Specification Left, 16th Aug., 1892-Accepted, 17th Sept., 1892
PROVISIONAL SPECIFICATION.
Improvements in Trip Expansion Gear for Steam Engines.
I THOMAS PARKER, Works Director of The Electric Construction Corporation
Limited of Wolverhampton in the County of Stafford do hereby declare the nature
of this invention to be as follows:
:-
This invention has for its object to provide simple and efficient trip expansion
gear for steam engines. The engine to which the invention is applied may have
Cornish double beat valves for admission of steam to the cylinder or cylinders and
oscillating valves for exhaust and the valves may be operated by means of
excentrics working off a countershaft parallel to and rotating with the crank shaft
but the invention is not limited to use with these details.
According to this invention the valves are lifted by bell-crank levers centered to
a fixed point and with one arm engaged with the valve spindle and the other arm
connected to one end of a lever centered upon a part which is raised and lowered
by connection with the governor the other arm of the levers being that upon which
trip tappets of the wiper act the said wiper being connected to a shaft oscillated by
an arm connected to the excentric as aforesaid.
The arrangement by means of which the lever aforesaid has vertical movement
imparted to its centre by the governor may consist of links supporting the centre
pin the said links being mounted upon an excentric on a shaft or pin turned
in bearings by means of an arm secured thereto and connected to a rod operated by
the governor each valve operating gear being so arranged and connected to such a
rod common to both. In place of links and an eccentric mounting; bell-crank
levers may be employed for the same purpose.
When the engine is working the tappets come in contact with the ends of
the aforesaid levers which are opposite the ends thereof which are connected to the
bell crank levers of the valve spindles and as the governor moves the said levers up
and down as aforesaid the ends of the levers are brought into such positions as to
be operated more or less by the tappets and so regulate the expansion as required.
Dated this 3rd day of November 1891.
J. H. JOHNSON & Co.,
47, Lincoln's Inn Fields, London, W.C., Agents.
COMPLETE SPECIFICATION.
Improvements in Trip Expansion Gear for Steam Engines.
I THOMAS PARKER Works Director of The Electric Construction Corporation
Limited of Wolverhampton in the County of Stafford 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:-
This invention has for its object to provide simple and efficient trip expansion
gear for steam engines. The engine to which the invention is applied may have
Cornish double beat valves for admission of steam to the cylinder or cylinders and
oscillating valves for exhaust, and the valves may be operated by means of
eccentrics working off a countershaft parallel to and rotating with the crank shaft
but the invention is not limited to use with these details.
According to this invention each admission valve is lifted by bell-crank levers
centered to a fixed point and with one arm engaged with the valve spindle and the
other arm connected to one end of a lever rod centered upon a part which is raised
and lowered by connection with the governor, the other arın of the lever or rod
[Price 8d.]

page_text: being that upon which the trip tappet of the wiper acts, the said wiper being
connected to a shaft oscillated by an arm connected to the eccentric as aforesaid.
And in order that my invention may be well understood I will describe with
reference to the accompanying drawing the best means with which I am acquainted
for carrying it into effect premising that I do not limit myself to the precise details
shewn as they may be varied without departing from the nature of my invention as
hereinbefore stated.
Figure 1 is a side elevation, and Figure 2 is a transverse section on the line 1. 2
Figure 1, of so much of a steam engine as is necessary to illustrate my invention.
S are the spindles of the valves to be operated. C are bell-crank levers centered
at c as aforesaid. One arm of these bell-crank levers is connected to, or engaged
with, the spindles S the other arms being connected to levers or rods K
centered at k.
These centres k have, as aforesaid, movement imparted to them from the
governor which movement is effected by means of links L, supporting the
centre pink, the said links L, being mounted upon an eccentric 6 on a shaft,
or pin B, turned in bearings 62, by means of an arm L² secured to the said shaft B
and connected to a rod R, operated by the governor, each valve operating gear
being so arranged and connected to such a rod common to both as shewn.
The said centres & will consequently have an up, or down movement imparted to.
them corresponding to the movement of the governor.
L' is the lever by which the wiper shaft W is oscillated, it receiving its move-
ment by the reciprocation of the eccentric rod A. On the ends of the wiper are
mounted the tappets T as usual. In place of links and an eccentric mounting;
bell-crank levers may be employed for the same purpose. When the engine is
working the tappets T come in contact with the ends of the aforesaid levers K,
which are opposite them and these being connected to the bell-crank levers C of
the valve spindles, as the governor moves the centres k of the said levers up and
down, as aforesaid, the ends of the said levers K are brought into such positions
as to be operated more or less by the tappets and so regulate the expansion as
required.
Dare the usual dash-pots by which the parts are returned to their normal
position.
The lead is in no way altered by the radial movement of the intermediate
pieces K. K and the range of cut off extends say from nil to three quarters of
the stroke.
The invention is of course not limited to the number of valves operated
as described as one two or more valves may it will be evident be operated as
desired.
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. In trip expansion gear for steam engines the mounting of the intermediate
rod, or lever, or rods, or levers, on which the wiper acts to operate the valve or
valves upon centres which are altered in their position by connection with the
governor substantially as, and for the purpose, hereinbefore described.
2. The arrangement constituting the trip expansion gear as hereinbefore
described and illustrated in the accompanying drawing.
J. H. JOHNSON & Co.,
Agents.