Improvements in Rotary Engines, Fans, Blowers, and the like.
Year: 1892

page_text: Date of Application, 24th May, 1892-Accepted, 2nd July, 1892
COMPLETE SPECIFICATION.
Improvements in Rotary Engines, Fans, Blowers, and the like.
1 GILMER CROWELL of No. 292 Graham Street, Brooklyn, Kings County, in
the State of New York United States of America Manufacturer 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 relates generally to cylinders employed in rotary engines, blast
fans, blowers and the like, wherein the radially sliding pistons or blades are
carried by a rotating hub or drum set eccentric to the approximate centre of the
cylinder.
In this type of engine it is exceedingly difficult to obtain perfect and satisfactory
results from the fact that there are points in the diameter of the stationary
cylinder where both ends of the piston do not accurately fill the cylinder, in
consequence of which leakage and loss of power or pressure results; for this
reason a sliding piston having no springs, packings, or followers, and carried by
a drum eccentrically journaled in a cylindrical case, has never, so far as I know,
been practicably used.
The objects of my invention are to avoid the above objections; and to provide
a novel construction whereby the radially sliding pistons or blades touch and
accurately fit diametrically opposite points at every part of the internal calibre
of the stationary cylinder without employing springs, packings, or followers,
and to provide a novel fan blade or piston for this special type of blower or
engine.
To these ends my invention involves first the novel cylinder bored to provide a
common diameter taken on lines through a predetermined point eccentric to the
approximate centre of the cylinder, the internal periphery of which cylinder is
formed substantially one half semi-cylindrical and the other on a curve formed by
a plurality of arcs with a gradually changing radius from the centre of rotation
of the piston; and second a similar cylinder bored from two different centres only.
In the accompanying drawings:
Figure 1, is a diagramatic view of the internal calibre of a cylinder according to
the first part of the invention illustrating its oval contour and the moving centres
from which it is bored.
Fig. 2, is a central sectional view of a like cylinder for use as an air blast,-blower
or engine.
Fig. 3, shows a scriber by which the contour of this cylinder may be obtained.
Fig. 4, a central section of a cylinder made after the second part of the
invention.
Referring to the first part of the invention and to Fig. 1, the bore of the
cylinder 1 has in general an oval contour consisting in the main of an arc 6
described by a radius 26 and having the point 2 for its centre, which are 6 constitutes
substantially one half of a circle. It may extend for a distance slightly greater
than one half of the cylinder as for instance between the points 5 indicated on the
are. The bounding chord of this half circle situated substantially on a line drawn
The remaining
through the centre of rotation of the piston, viz. the point 24.
arc 27 of the cylinder is enscribed from a moving centre moving in the path
indicated by the oval line of dots a, with substantially the line 28 as a radius. From
the foregoing it will be apparent that the centre of the boring tool, when a movable
tool is used, instead of moving cylindrically, will enscribe the oval a, resting for a

page_text: time at the point 2 to enscribe the arc 6, and then constantly moving to enscribe
the irregular arc 27. until it again reaches the point 2. The effect of this is to
provide an irregularly formed oval bored cylinder, irregular so far as the contour
or are 27 is concerned, and which arc with the other arc 6 provide a contour
adapted to a piston or blade set to revolve from an axis 24 eccentric with respect
to the approximate centre of the cylinder whereby the extremities of such piston or
blade will preserve accurate and close contact or fit throughout the diameter of
the internal calibre of the cylinder.
With this understanding of the cylinder and one manner in which it may be
bored, Figure 2 shows its use in a rotary engine or blower where the numeral 1
designates the stationary cylinder. The radially sliding pistons or blades 12 are
carried by a rotating drum 13, journaled eccentrically in the stationary cylinder on
the axis 24. As there is a positive measured distance across the cylinder on the
line 7-8 which is co-ordinate to the distance across the cylinder on the line 9-10,
the opposite extremities of the pistons or blades 12 will, in their revolution, preserve
accurate and close contact or fit throughout the diameter of the internal calibre,
without liability of leakage at any point past a blade whereby I attain, by actual
demonstration, twenty per cent. increased power or pressure in the working of the
blower or engine. Whether the fan or piston blades be driven or serve to drive
is immaterial, and therefore I do not enter into further detailed illustration and
explanation in this respect as it is not essential for the proper understanding of my
improvement.
I have shown in Fig. 3 a means by which the contour of the cylinder may be
readily obtained. 30 is a base piece having an interior curved surface formed on
a radius which is substantially that of the cylinder to be produced. This surface
is a half-circle. 31 is an eccentrically situated guide pin having the position of
the centre of revolution of the piston or blade in the finished cylinder. The
parts 30 and 31 may be fixed in place upon any suitable surface. 32 is a bar which
is of a length, from its end 33 to a scriber point 34 with which it is provided,
equal to the definite diameter hereinbefore referred to and equal in length to the
piston or blade. Said bar is formed with a slot or other guide 35 adapted to
engage the pin 31. In using the scriber the end 33 of the bar 32 is held firmly
in contact with the base piece 30 and revolved round the pin 31. This will cause
'the point 34 to describe a curve 36, which, together with the curve of the
base piece 30, will constitute the pattern for the entire contour of a cylinder
whose shaft, or centre of rotation of the piston, is to be situated at the point 31.
In the other form of cylinder shown in Fig. 4, the internal calibre is first bored
on the centre indicated by the numeral 2, to form a true circle and subsequently
1 lower or otherwise vertically adjust the cylinder in the boring mechanism and
bore it on a centre indicated by the numeral 3, which is slightly eccentric to the
centre 2, so that the internal calibre is thereby struck from two different centres
and not more than two. This forms the internal surface with a single, long,
crescent shaped concavity as at 4, which vanishes at the points 5, into the true
circular part 6. By this construction the diameter of the internal calibre is
increased at the diametrical line 7-8 and at this point the said diameter is
co-ordinate with the diameter at the diametrical line 9-10. This is paramount for
the perfect working of the radially sliding fan or piston blades 12 carried by a
rotating drum 13, journaled eccentrically in the stationary cylinder. As there is
a positive measured distance across the cylinder on the line 7--8 which is
co-ordinate to the distance across the cylinder on the line 9-10, the opposite
extremities of the fan or piston blades 12 will, in their revolution, preserve
accurate and close contact or fit throughout the diameter of the internal
calibre:
It has been proposed to strike the internal calibre of a cylinder from three
different centres, but the construction has never been worked in consequence of the
impossibility of obtaining fan-blades or pistons that will practicably operate
conjointly therewith and avoid leakage without using spring followers, packings or

page_text: the like, for the working fluid will, at points in the cylinder, blow past the
extremities of the pistons.
The axis of the rotating drum in my construction is composed of a through
shaft 14 journaled eccentrically in the cylinder-heads and that the fan-blades may
be practically continuous in a radial line, the pins 15 are provided each passing
through perforations in the shaft with either end in contact with the end of a
piston or blade, there being a pair of pins for each pair of blades, the whole free
to slide back and forth with respect to the axis, as shown in Fig. 2, or yokes
embracing the shaft may be employed as shown in Fig. 4.
While the drum is journaled eccentrically in the cylinder and the internal
diameter thereof is formed by a plurality of arcs struck from a moving centre,
still the extremities of the fan-blades accurately fit the cylinder at every point in
the revolution of the fan and there is no possibility of the air or other fluid blowing
past the extremity of a blade, whereby the power of the engine is enlarged and
good results attained.
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. The hereindescribed cylinder, the internal periphery of one half of which
is semi-cylindrical, and the other portion of which is on a curve formed by a
plurality of arcs with a gradually changing radius from the centre of rotation of
the piston.
2. The hereindescribed cylinder, the internal periphery of one half of which is
semi-cylindrical, and the other portion of which is on a curve formed by a plurality
of arcs with a gradually changing radius from the centre of rotation of the piston,
the bounding chord of the semi-cylindrical portion being situated substantially on
a line drawn through said centre of rotation,
3. The described scriber adapted to slide longitudinally on a fixed pin set
eccentric to a semi-circular base, which base acts as a guide for one end of the
scriber, the other end having a marking or cutting point.
4. The combination of the stationary cylinder having its internal calibre struck
from two different centres only to form the single crescent shaped concavity and
leave the remainder of the calibre truly circular, with the drum eccentrically
journaled in the cylinder and a fan or piston blade sliding radially and having its
two extremities superficially bearing against the inside of the cylinder, substantially
as described.
5. The combination of the stationary cylinder having its internal calibre struck
from two different centres only to form the single crescent shaped concavity and
leave the remainder of the calibre truly circular, with the drum, the through shaft
journaled eccentrically in the cylinder-heads and the slotted yokes carrying the
fan or piston-blades and sliding on the shaft with the fan or piston blades having
their extremities in superficial contact with the internal calibre described, substan-
tially as set forth.
T
CAL 1900
PHILIP M. JUSTICE,
55 & 56, Chancery Lane, London, Chartered Patent Agent.