Improvements in Motors Driven by Steam or other Elastic Fluid.
Year: 1889

page_text: Late of Application, 4th Mar., 1839-4ccepted, 1st Mar., 1890
COMPLETE SPECIFICATION.
Improvements in Motors Driven by Steam or other Elastic Fluid.
We, LUDWIG BOHNEN, Merchant, & MORITZ KLEBER Jr. Mechanician, both of
Berlin, in the German Empire, do hereby declare the nature of our said 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 relates to a rotary motor in which two revolving bodies of suitable
form are so placed in a casing of convenient shape, and so rotate with reference to
one another that one forms, as it were, the wall of a gradually increasing chamber
whilst the other forms one end thereof.
The construction of these bodies or parts and the peculiar manner of their operation
permit packing of the contiguous surface to be dispensed with. The surfaces are
not exposed to any large amount of wear so that if the motor is carefully made in
the first instance it will be more durable than motors of the usual construction..
In the accompanying drawings Fig. 1 is a plan view of this motor one end or head
being removed.
Fig. 2 is a section parallel with the main shaft.
Fig. 3 a section at a right angle to the main shaft.
Fig. 4 shows how the larger revolving body hereinafter termed the piston and the
smaller one, hereinafter termed the disc, work together.
Figs. 5 and 6 show the position of these parts at various periods during
operation.
Fig. 7 shows the "piston" in side elevation.
Fig. 7 a modification of the same.
Figs. 8 to 16 show various details.
In a bored cylindrical casing A moves a rotary body B acting as, and herein
termed the piston. The cylinder is at the two sides closed by the heads a a which
are fitted with conical bearings for the passage of the main shaft C which also extends
through the piston B. The piston B is cut out or has a kind of semicircular groove
(Fig 2) in which are provided two ribs B2, B3, each forming half a turn of a screw-
thread, they are opposite to one another, of equal height throughout, see figs. 4
and 7. As will appear from Fig. 9 said ribs bear closely against the inner wall L of
the casing A and are level with the cylindrical portions or collars B¹ (figs. 2, 4 and 7)
of the piston. The helical edges of the ribs B2 B3 are shut off towards the casing A
on the one hand by a semicircular shoulder L fixed on the casing and shaped to
correspond with the groove in the piston, on the other hand by a disc D exactly fitting
the groove of the piston. The said dise is mounted and rotates on a spindle H Fig.
placed at right angles with the niainshaft C. This disc separates the steam-inlet and
outlet ports. The conical journals J, J, of the spindle H run in suitable bearings
provided in the casing A and are adjusted by means of a set screw K. To allow the
ribs B2, B3 to pass through the disc when the piston revolves the disc is provided
with slots, and in order to admit the ribs more readily into the slots their lower
sides D¹ (Fig. 5) are shaped like knife-edges. As it is required to make a steam-
tight joint where the ribs pass through the disc, the following arrangement is
adopted.
The disc D is composed of two plates D D (Figs. 9-12 & 15) connected by
screws and these plates are slotted where required for the passage of the ribs. On
the inner side of plate D' where the same constantly slides upon the under
surface of the rib the knife edge D' is provided (Fig. 6), whilst the ribs bear with
their leading edges B B (Fig. 7) against the part D (Fig. 8) of the disc D; the
surfaces B B are packed by the movable part D³ of the disc.

page_text: The movable part or slide D³ is loose on spindle H and the plates D* and D³ hold
it perpendicularly to the ribs B2 B³. Within suitable recesses of the plates D* D³
are provided springs G which lightly press the slide or movable piece D³ against that
surface of the ribs B2 B3 which is turned towards the steam supply and this forms the
packing. This slide is the only part exposed to wear and that takes place only by
its sliding along the upper surfaces of the ribs B3 B³. This wear however causes no
leakage as the slide is by the springs G caused to bear against the ribs and is thus
automatically set until it is almost entirely worn away. It may readily be replaced by
taking the dise D apart and inserting a fresh slide.
When the shaft C rotates the rib B² engages with the knife edge D¹ of the disk D
presses this downward and the spring slide B³ upward as much as corresponds to the
thickness of the rib (Fig. 5) the spring slide D3 bearing upon the upper surface of
the rib. The inlet port is directly behind the disc D so that the point of the rib B²
is forthwith seized by the steam or other elastic fluid when it arrives within the inlet-
area and the piston is rotated. The steam or the like now fills the gradually increasing
space between disc D and the rib, thus acting upon a continuously increasing piston
surface, or when expansive working is employed with a constant power.
When
the point of rib B3 and the end of rib B2 have passed the disc, the dead steam is
exhausted through the port or tube M (Fig. 3).
Instead of two ribs opposite to one another a single rib B (Fig. 7ª) may be used
and this would of course form an entire turn of a screw.
This engine or motor, compared with others heretofore known presents the
advantage that the elastic fluid is more perfectly utilised and that the dis-
advantageous side-pressures in the bearing are avoided. The working parts are
thus less liable to wear and the machine will always, or for a long time at all
events, work uniformly well if only carefully made at first.
It must be pointed out that the piston B does not scrape against the casing A, nor
the disc D against the piston B, the parts being only fitted closely enough to enable
the lubricant to act as the packing.
Having now particularly described and ascertained the nature of our said
invention, and in what the same is to be performed we declare that what we
claim is :-
- 1.) A rotary motor working by steam or other elastic fluid consisting of a casing A
wherein a rotary piston B and a disc D are placed at an angle to one another
and work in the manner set forth all substantially as described and shown in the
drawings.
2.) In a motor constructed as herein above specified a rotary piston grooved or
recessed and provided with the ribs as described.
3.) In a motor such as herein above specified the disc D having slots for the
passage of the ribs B and fitted with the movable slide D³ as and for the purposes set
forth and shown.
Dated this 4th day of March 1889.
BERNHARD DUKES,
226, High Holborn, London, W.C., Agent for the Applicants.