IMPROVEMENTS IN VARIABLE EXPANSION GEARS
Year: 1879

page_text: LETTERS PATENT to Ernst August Wortmann, of Ruhrort, in the German
Empire, for the Invention of "IMPROVEMENTS IN VARIABLE EXPANSION
GEARS"
Sealed the 1st August 1879, and dated the 13th February 1879.
PROVISIONAL SPECIFICATION left by the said Ernst August Wortmann
at the Office of the Commissioners of Patents on the 13th February 1879.
ERNST AUGUST WORTMANN, of Ruhrort, in the German Empire. IMPROVEMENTS
IN VARIABLE EXPANSION GEAR."
"
By means of this Invention the grade or amount of expansion is varied by varying
the travel of the expansion slide valve. The main slide valve has steam ports right
through; the expansion slide, which works on the back of the main slide, has a
middle port right through.
The expansion slide valve obtains its movement from an eccentric by means of a
rod which is jointed to a block working in one of the sweeps of a double link or
sweep turning on a fulcrum at one end, say the lower end; in the other sweep there
is a block which is jointed to a connecting rod having a cross head working in a
guide, and jointed to the expansion slide valve rod: To render the stroke of the latter
variable there is a double armed lever or beam having its fulcrum on the double
link and at each end by jointed rods connected to each of the link blocks. The
fulcrum spindle of the beam is by levers and rods connected to the rising and falling
sleeve or other part of the governor influenced by the variable load on the engine.
When thus; for instance; the balls of the governor swing out by any increment of
speed owing to decreased load on the engine, then the aforesaid beam on the double
link is raised at one end, thereby carrying the block at the eccentric rod end up
with it, and lowered at the other end, thereby depressing the block in the other
sweep of the double link, thus shortening the stroke of the expansion slide and
cutting off the steam at an earlier part of the stroke, that is, admitting less steam
into the cylinder.
The beam on the double link may also, if desired, be moved by hand.
Between the back of the expansion slide valve and the inside of the slide box
cover I place a wedge plate with adjusting screw or screws at each end; there is a
port through the plate for the steam from the steam pipe to enter through the two
slide valves, but not into the slide box itself; the steam pressure is thus taken off
the slide valves.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Ernst August Wortmann in the Great Seal Patent Office-on-the-13th-
August 1879.
- ERNST AUGUST WORTMANN, of. Ruhrort, in the German Empire.
IN VARIABLE EXPANSION GEAR."
"IMPROVEMENTS
By means of this Invention the grade or amount of expansion is varied by varying
the travel of the expansion slide valve. The main slide valve has steam ports right
through the expansion slide, which works on the-back of the main slide, has a
middle-port right-through."
The expansion slide valve obtains its movement from an eccentric by means of a
rod which is jointed to a block working in one of the sweeps of a double link or
sweep turning on a fulcrum at one end, say the lower end; in the other sweep there
is a block which is jointed to a connecting rod having a cross head working in a
guide, and jointed to the expansion slide valve rod. To render the stroke of the
latter variable there is a double armed lever or beam having its fulcrum on the
double link and at each end by jointed rods connected to each of the link blocks.
The fulcrum spindle of the beam is by levers and rods connected to the rising and
falling sleeve or other part of the governor influenced by the variable load on the
engine.
The beam on the double link may also, if desired, be moved by hand.
Between the back of the expansion slide valve and the inside of the slide box
cover I place a wedge plate with adjusting screw or screws at each end; there is a
port through the plate for the steam from the steam pipe to enter through the two-
slide valves, but not into the slide box itself; the steam pressure is thus taken off
the slide valves..
.
And in order that this my Invention may be more fully understood, I will now
describe the same with reference to the accompanying Drawings.
Figure 1 is a side elevation, Figure 2 a plan partly in section, and Figure 3 a
cross section of an engine constructed according to this Invention; Figure 4 is cross
section through the steam cylinder. a is the main slide and b the expansion slide.
working thereon, both having ports right through; the inner edges c produce the.
cut off. The expansion slide b is worked by rod d from an eccentric; this rod is at
jointed to a block which moves in one of the sweeps or links of a double link f
turning on the fulcrum bracket e on the bed plate; in the other sweep of the double
link there is a block which at o is jointed to the rod g; this latter is by a cross-
head h working in a guide connected to the expansion slide rod.
is a double armed lever or beam having its fulcrum spindle k on the double
link f, and by means of the rods or links n, n, connected to each of the link blocks.
On the same spindle is fixed a lever m, which by rod q is connected to a lever ;
the latter is fixed on the same weighshaft as the levers, which-by-the-rod-t-is-con-
nected to the lever v, working in the rising and falling sleeve of the governor.
The sweep for the block at o is part of a circle; the sweep for the block at p is
composed of two circle parts; the centres and radii have to be formed by construc--
tion, so that the expansion slide moves equally to the right and to the left.
When the balls of the governor swing out by any increment of speed owing to
depressed load on the engine, then the beam on the double link f is raised at one
end, thereby carrying the block at the eccentric rod end p up with it, and lowered
at the other. end, thereby depressing the block at o in the other sweep of the
double link f, thus shortening the stroke of the expansion slide b, and cutting off
the steam at an earlier part of the stroke, that is, admitting less steam. into the
cylinder.
u is a wedge plate placed between the back of the expansion slide. and the inside.
of the slide box cover, and adjustable by means of set screws, as shewn in Figure 4;
the steam passes through it. When the openings or ports through the plate u coin-

page_text: cides with that through the expansion slide b, which happens twice in every
revolution of the engine shaft, the expansion slide is quite without steam load on it,
and in these moments the governor can with very little force cause the levers
8, r, m, and l, and the link ƒ to shift in position, thus altering the grade of expansion
as required by the load on the engine. The plate u being steam tight against the
slide box cover and the expansion slide, the steam does not enter the slide box, and
very light packing, if any, is needed in the stuffing boxes of the slide rods, if used
therewith at all.
And having thus described and ascertained the nature of this Invention, I declare
that I claim,
Firstly. The double link f in combination with and actuated by a governor or
hand gear for altering the expansion automatically or by hand, substantially as set
fortb.
Secondly. The means, substantially as set forth, for taking the steam load off the
expansion slide, and for simultaneously preventing the steam from entering the
slide box.
In witness whereof, I, the said Ernst August Wortmann, have hereunto set
my hand and seal, this Fifth day of August, in the year of our Lord One
thousand eight hundred and seventy nine.
ERNST AUGUST WORTMANN. (L.S.)