IMPROVEMENTS IN AND RELATING TO SLIDE-VALVE APPARATUS, CHIEFLY DESIGNED FOR STEAM AND OTHER ENGINES
Year: 1879

page_text: LETTERS PATENT to Louis Schwartzkopff, Director of the Berliner Maschinen-
bau-Actien-Gesellschaft, vormals L. Schwartzkopff, of Berlin, Prussia, for the
Invention of "IMPROVEMENTS IN AND RELATING TO SLIDE-VALVE APPARATUS,
CHIEFLY DESIGNED FOR STEAM AND OTHER ENGINES." A communication from
Emil Kaselowsky and Carl Prött, of Berlin, Prussia.
Sealed the 11th November 1879, and dated the 15th May 1879.
PROVISIONAL SPECIFICATION left by the said Louis Schwartzkopff at the
Office of the Commissioners of Patents on the 15th May 1879.
LOUIS SCHWARTZKOPFF, Director of the Berliner Maschinenbau-Actien-Gesell-
schaft, vormals L. Schwartzkopff, of Berlin, Prussia. " IMPROVEMENTS IN AND
RELATING TO SLIDE-VALVE APPARATUS, CHIEFLY DESIGNED FOR STEAM AND OTHER
ENGINES." A communication from Emil Kaselowsky and Carl Prött, of Berlin,
Prussia.
This Invention relates to a slide valve and operating parts chiefly designed for
the distribution of steam in steam engines, and in this application it is ordinarily
combined with an apparatus for variable expansion of the steam. But it may with
equal advantage be applied to gas and air engines and pumps, and can also be used
for opening and closing pipes, channels, and other conduits for the circulation of
fluids, air, or gas.
The principal peculiarity consists in the slide valve being operated in such a
manner that all its points describe circles of the same size. On the accompanying
Sheet of Drawings a slide of this kind is represented in combination with a three-
cylinder engine; B is the valve-box with the cover removed; a is the slide-valve
which admits steam successively to the cylinders A, A1, A2. The same is operated
by a pin b (shewn in dotted lines) which is attached to the crank of the engine in
such a manner that its centre line is excentrical to the main shaft, and which
projects into a hole within the slide-valve. This pin by its rotation around the
centre line of the main shaft causes the centre of the slide to move in a circle k ;
d, d, d, are three auxiliary or guiding cranks turning freely with one pin in a hole
in the slide face of the cylinders, and with the other pin in an eye forming part of
the slide. The three cranks d have the same throw as the pin b; moreover they

page_text: are parallel to the line drawn from the centre of the pin b to its centre of rotation,
and they will remain parallel to this line and therefore with each other when the
pin b revolves. In consequence every point of the slide is caused to move in a
circle congruent with circle k or with the circles described by the cranks d, and
any line drawn on the slide will nove parallel to itself.
h, h, h, are the steam-ports on the lower face of the slide which are parallel to
the cylinder-ports; the ports i, 1, 2, on the top of the valve are placed at right
angles to the former, and each of them communicates by a suitable passage with
the corresponding lower port. With this arrangement alone the slide would
distribute the steam in the cylinders without expansion. For the purpose how-
ever of cutting off the steam at any desired point of the stroke, stationary but
adjustable expansion-plates or slides è are applied, one of which only is shown in
the Drawing. This slide or plate e causes the port to be closed as soon as pin b
has moved in the direction of arrow far enough towards the left as to carry
the said port entirely under the plate c. The three expansion-plates can be shifted
simultaneously by a three-branched lever (not shown in the Drawing), so as to
cause the ports i, 1, 2, to be closed at an earlier or later period of the stroke,
and they are guided by suitable grooves formed on the inside of the steam-chest-
cover. The said lever is fixed to a short shaft passing through the valve-box
cover, and connected with a hand-lever or with the governor of the engine.
It is not necessary that the three valves for the three cylinders be united into
one as represented; they may on the contrary be separate from each other, and
connected together in a suitable manner.
The slide may also be adapted to ordinary double-acting cylinders, air and gas
engines, pumps, etc., and it may be constructed so as to be employed for motors
with reversing-gear.
In ordinary cylinders it may be of advantage to replace the auxiliary or guiding
cranks d, d, d, by other guides. The valve may for instance slide in a frame,
which frame again moves in guides in a perpenticular direction. to the movement
of the valve. This principle of motion, which is fully explained in Professor
Reauleaux' well known work on kinematics, and named therein "swinging double
slides," may be applied in different variations.
In a motor with reversing gear the above mentioned pin or stud 6 operating the
slide valve may be replaced by an excentric, which by air of a long pitched screw
may be shifted from the outside so as to bring the valve at any moment into any
desired position.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by the
said Louis Schwartzkopff in the Great Seal Patent Office on the 11th
November 1879.
LOUIS SCHWARTZKOPFF, Director of the "Berliner Maschinenbau-Actien-Gesell-
schaft, vormals L. Schwartzkopff, of Berlin, Prussia. "IMPROVEMENTS IN AND
RELATING TO SLIDE VALVE-APPARATUS, CHIEFLY DESIGNED FOR STEAM AND OTHER
ENGINES." A communication from Emil Kaselowsky and Carl Prött, of Berlin,
Prussia.
This Invention relates to a slide-valve and operating parts and chiefly designed
for the distribution of steam in steam-engines, and in this application it is
ordinarily combined with an apparatus for variable expansion of the steam. But it
may with equal advantage be applied to gas and air engines, and pumps, and can
in general be used for shutting off and opening the circulation of fluids in pipes,
channels, and other conduits.
The principal peculiarity of the arrangement consists in the slide-valve being
operated in such a manner that all its points describe circles of the same size.
On the annexed Sheet of Drawings a slide-valve of this kind is represented in
combination with a three-cylinder engine; Fig. 1 being a front view of the engine
with valve-box cover detached; Fig. 2, a vertical section; Fig. 3, a view of the
valve alone, and Fig. 4, a view of the valve-box cover from below showing one of
the expansion-plates and its guiding parts.
B is the valve-box (shewn in Figure 1 with the cover removed); a is the slide-
valve which admits steam successively to the cylinders A, A¹, A". The same is
operated by a pin b which is attached to the crank c of the engine in such a
manner that its centre-line is excentrical to the main-shaft, and which projects into
a hole in the slide valve. This pin by its motion around the prolonged centre-line
of the main shaft causes the centre of the slide to move in a circle k, Fig. 3; d, d, d,
are three auxiliary or guiding cranks turning freely with one pin in a hole in the
slide-face of the cylinders, and with the other, pin in an eye forming part of the
slide. The three cranks d have the same throw as the pin b; moreover, they are
parallel to the line 1, 2, drawn from the centre of the pin b to its centre of rotation,
and they will always remain parallel to this line and therefore with each other
when the pin b revolves. In consequence, every point of the slide is caused to
move in a circle congruent with circle k, or with the circles described by the
cranks d, and any line drawn on the slide will move parallel to itself.
h, h¹, h, are the steam-ports on the lower face of the slide which are parallel to
the cylinder-ports; the ports i, i¹, 2, on the top of the valve are placed at an angle,
and by preference at a right angle to the former, and each of them communicates
by a suitable passage with the corresponding lower port. With this arrangement
alone the slide will distribute the steam in the cylinders in the same manner as
common distributing-valves. For each cylinder-port only that part of motion of
the slide-valve which is vertical to the port is utilised for opening and closing the
same; but no more expansion is caused than by distributing-valves in general.
For the purpose however of cutting off the steam at any desired point of the stroke,
stationary but adjustable expansion plates e, e', e², are applied.
The plate e causes the port i to be closed as soon as pin b has moved in the
direction of arrow 1, far enough towards the left as to carry the said port entirely
under the plate e; and the same operations take place successively with regard
to the other plates e¹ and e2, and two ports 1 and 2 For the expansion it is thus
the part of motion of the slide parallel to the cylinder steam-ports which is
utilised. The three expansion-plates can be shifted simultaneously by a three-
branched lever g, so as to cause the ports i, i, 2, to be closed at an earlier or
later period of the stroke, and they are guided by means of lugs on their back,
sliding in suitable grooves or between projections formed on the inside of the

page_text: valve-box cover. The said lever g is fixed to a short shaftf passing through a
stuffing-box on the valve-box cover, and connected with a hand-lever, or with a
lever jointed by a rod to the governor of the engine for the purpose of automatic
regulation.
It is not necessary that the valves for the three cylinders be united into one
as represented; they may on the contrary be separate from each other, provided
they be connected together rigidly by rods, or in other suitable manner. Moreover,
it may be observed that two auxiliary cranks d are sufficient to guide the slide-
valve in the desired manner, and that the excentric pin 6 may as well act on any
point of the valve not being its centre.
b
"
The described slide-valve and the mode of operating the same may also be
applied to ordinary double acting steam cylinders, and to air and gas engines;
besides, the main slide with operating parts can be used with pumps, and for the
purpose of opening and closing water or gas-conduits or other pipes or channels.
In some cases, especially in ordinary cylinders, it may be of advantage to replace
the auxiliary or guiding cranks d, d, d, by other guides. As shown in Fig. 5, the
valve a which is actuated by a crank or pin b rotating in a circle as before slides
up and down in a frame w, which is guided horizontally between ledges x on the
sides of the steam-chest. This arrangement will cause every point of the valve to
move in a circle congruent with the circle described by the said pin as in the first
case, and consequently, the distribution and expansion of steam will take place in
an analogous manner. This device may be varied in form without departing from
its principle, provided only that the valve be guided by an intermediate piece in
one direction, while the said piece is guided in another direction by preference
The
perpendicular to the former by the steam-chest or any fixed part of the same.
inode of regulating the expansion-plates not presenting any new features, the parts
serving for this purpose have not been shown again in Fig. 5.
In a motor with reversing gear, the above mentioned pin or stud b operating
the slide-valve may be repla ed by an eccentric, which by aid of a long-pitched
screw may be shifted from the outside, so as to bring the valve at any moment
into any desired position.
This part of the Invention is shown by the Figures 6, 7, and 8, with regard
also to a three cylinder engine. The pivot b' which is placed in a line with the
main shaft of the engine is hollow, and encircles the end of a rod o, m, l, provided
with one or more feathers corresponding with grooves in the hollow pivot. This
rod must therefore revolve with the pivot, while it may be shifted longitudinally
without changing its angular position with regard to the same. The part m of the
said rod is provided with one or more long-pitched screw-threads meshing with
corresponding inside threads of the excentric n, and consequently driving the
excentric. The thinner part o of the rod o, m, 1, passes through a tube or sleeve p,
and is secured thereto by a ring q in such a manner that it may revolve freely in p,
whenever the
whereas the rod is forced to slide longitudinally together with tube
latter is thus shifted. The tube p cannot revolve on account of the fixed feather 8
meshing into a groove on o. The boss of the hand-wheel is connected in such a
manner with the bracket t that it is capable of rotary motion only as will be
understood from the Drawing. By this arrangement the angular position of the
excentric n with regard to the crank may be changed. Supposing the hand-wheel
to be rotated in such a sense as to cause the tube p with the rod o, m, l, to be
drawn forward, the rod not being capable of revolving relatively to the pivot b¹ on
account of the feathers on its part l, will cause the threads m to shift the excentric
n in a rotary sense with regard to b', until it is brought into the position for
reverse motion of the engine. This turning of shifting of the excentric may be
done at any time, whether the engine be at rest or working.
When the excentric is shifted for reverse motion, the expansion plates must be
adjusted accordingly. This is carried out by hand-lever u connected with the
inside lever v which actuates the three-armed piece g; an angular motion of this
piece causing it to simultaneously shift, the three expansion plates to the other side

page_text: of the steam-ports in the distribution slide. When the hand-lever u is in its centre
position, the expansion-plates cover all the ports in whichsoever position the
distribution-slide may be, so that the engine is in such case stopped.
The described reversing arrangement may of course be applied to other systems
of steam-engines provided with the new slide-valve-apparatus, and the slide-valve
may be guided by the auxiliary cranks d, or by the intermediate sliding piece or
frame shown in Fig. 5.
Having thus described the nature and object of this Invention, and the manner
in which it is to be carried out in practice (as communicated to me by the
inventors), I hereby claim as new and essential features of the same,-
1. A slide-valve a actuated by an excentric pin b or an excentric, and guided by
two or more auxiliary cranks d'or their equivalent, such as the intermediate sliding
piece or frame w, Fig. 5, as and for the purpose described.
2. In combination with the slide-valve a actuated by an excentric pin b or an
excentric, and guided by two or more auxiliary cranks d or an intermediate sliding
piece or frame w, and having channels whose openings i and h are placed at an
angle to each other, the stationary but adjustable expansion-plates e, as described
and for the purpose specified.
3. In combination with the slide-valve a operated and constructed as described
and provided with expansion-plates e, the lever g actuated by hand or by the
governor of the engine, as and for the purpose specified.
4. In combination with the slide-valve a constructed and operated as described,
the reversing-gear consisting of a rod o, m, l, sliding on feathers in pivot b', and
actuating by its screw-threads m the excentric n, which rod upon being shifted
longitudinally by means of sleeve p causes the excentric to be shifted in a circular
sense for forward or backward motion, substantially as herein before specified.
In witness whereof, I, the said Louis Schwartzkopff, have hereunto set my
hand and seal, this Third day of October, in the year of our Lord One
thousand eight hundred and seventy-nine.
LOUIS SCHWARTZKOPFF. (L.S.)