Improvements in Locomotive, Marine, and other Engines.
Year: 1888

page_text: COMPLETE SPECIFICATION...
Improvements in Locomotive, Marine, and other Engines.
I EDWARD ALBERT JEFFERIES, of Wootton Bassett Station, Swindon, in the
County of Wiltshire, Coal and Salt Merchant, 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 :—
In working locomotive and marine engines at slow speed the slide has say a quarter
of an inch inside and outside lap and when the engine is thrown into full gear the
slide travels perhaps two inches and a quarter, and when the engine has attained full
speed the driver pulls the reversing lever back towards the centre to shorten the travel
of the slide from two and a quarter inches to say three quarters, and the engine does
not begin to exhaust her steam on the present plan before the steam reaches the other
side of the piston and thus the exhaust steam is locked in the cylinder until the
hollow of the slide travels the three quarters of an inch to allow it to escape.
According, to my invention in working a locomotive, marine, or other engine,
when it has obtained sufficient speed instead of pulling back the reversing lever as
now I keep it in full gear and insert into each feed port a piece of steel or other
material to reduce it in size accordingly as the boiler supplies steam, and thus give
to the slide an inch or more outside lap, so that by the time the slide has travelled
say one quarter the distance the exhaust port at the other end will be open to the
full and the steam will be admitted into the cylinder at one quarter stroke, full at
half stroke, shut at three quarter stroke and allowed to expand the rest of the
stroke.
'
In the accompanying drawings
Fig. 1. illustrates a section of cylinder and valve-box and Fig. 2. a plan of cylinder
with valve casing removed to show the face plate. A are the inlet ports and B the
exhaust these ports being constructed of the usual dimensions relative to the size of
the cylinder. C are the two bars of metal which I introduce through stuffing
boxes D fixed to the side of the valve box and so reduce the feed ports to about one
half their proper area.
The bars are attached to a cross-head E and may be worked
simultaneously by any suitable screw or lever arrangement. On starting out of

page_text: stations or ascending up banks the bars will be withdrawn thus making the engine
into a powerful slow one, and when the bars are again inserted into each port it will
again at once be converted into a high speed engine. Of course I do not confine
myself to any size of pieces, that being a question which would have to be decided
by the builder. In applying my invention to marine engines the bars C could have
a long taper form the engineer working the engine the exact length of stroke the
steam was to be cut off at, so as to work as economically as possible. It will be seen
that by my invention the slide travels the full length of the stroke, for the hollow
part thereof to take the exhaust steam off the back of the piston. On the present
system of working locomotive engines the more the reversing lever is drawn back the
greater the back pressure is on the piston.
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:
1st. In a steam-engine the method of varying the area of the ports by means of
sliding bars such as C operated substantially as and for the purpose described.
2nd. The improvements in steam engines operating in manner and for the purpose
substantially as described and illustrated in the accompanying drawings.
Dated this 27th day of April 1888.
HUGHES, ELI & HUGHES,
76, Chancery Lane, W.C.,
Agents for the Applicant.
HUGHES, ELI & HUGHES,
76, Chancery Lane, W.C.,
Agents for the Applicant.