Note: Descriptions are shown in the official language in which they were submitted.
399~;2
AXIAh FLOW ROTARY SEPARA'rOR
Cross Reference to Related Ap~Lication
Canadian Patent Application Serial No. 535,5~7 filed on
27 April 1987 in the name of West et al, entitled "Faeding
Arrangement for an Axial Flow Rotar~ Separator" and assigned
to the assignee oE the invention herein, is directed in
preferred embodiment to the feeding of a twin rotor axial flow
rotary separator using two-stage feed rotors in combination
with a feed casing which includes truncated cylindrical
surfaces. To the extant that the invention disclosed and
claimed in Canadian Serial No. 535,547 is disclosed herein, it
is done so only for completeness of description of the
operative environment of the invention claimed herein and thus
forms no part of the invention claimed herein.
sackqround of the Invention
This invention concerns axial flow rotary separators of
the type used to separate threshed material in combine
harvesters and more particularly separators in which rotors
with tined or finger-like elements are used to propel material
circumferentially within a cylindrical casing while helical
guide elements provide at least a part of the required axial
indexing effect.
In separator rotors using tines or finger-like elements
it is already known to provide some form of yielding or
pivoting of the element with respect to the rotor frame. Hall
et al for example, in U.S. Patent Mo. 4,611,605, discloses
finger elements pivoted about an axis perpendicular to the
rotor axis so that the fingers, while in engagement with a
crop material mat, spiraling downstream under the influence of
helical guide vanes, may move pivotably downstream with the
mat so that the flow of the mat is not impeded. Schlayer in
U.S. Patents 1,688,662, 1,744,334 and 1,744,336 suggests
yieldability of crop engaging elements in a plane
perpendicular to the rotor axis but not pivoting or yielding
in the direction taught by Hall. Schlayer (in `334) also
teaches twisting the radially outward tips of the crop
engaging elements so as to "feed the material in the direction
~2~3~2
towards the discharge end~ Such feeding action is caused by
the current of air produced by the helical form and also bv
the threshing members acting on the material in angular
direction."
Use of the radially outward tip of the crop engaging
element of the rotor to assist in axial propulsion is also
disclosed in U.S. Patent 723,670, Hixson, in which the tip of
a basically radially extending rod is bent into a generally
axial but somewhat helical alignment so as to assist in axial
propulsion while at the same time passing close enough to a
separating grate portion of the casing, to assist in wiping
material over the grate~
Each of the known crop material engaging element
arrangements, by themselves or in combination with the
particular separator casings and other components with which
they are associated, operate moderately successfully but leave
room for improvement.
Summary of the Invention
Accordingly, it i5 an object of the invention to provide,
in an axial flow rotary separator rotor, generally radially
extending crop material engaging elements which are yieldably
mounted on the rotor frame and which are modified at their
radially outward tips to provide generally helical surfaces
contributing to axial propulsion and which, in combination
with a suitable grate in a generally cylindrical separator
casing, separate threshed grain efficiently with a minimum of
chaff generation while handling a variety of crops over a wide
range of feed rates.
In axial flow rotary separators according to the
invention, rotors are preferably mounted eccentrically so
that, during a portion of the rotor revolution, the radially
outward portion of the crop material engaging element sweeps
closely over a ~oraminous portion or grate of the casing. The
element itself includes a deflecting surface of such axial
extent as to have a significant wiping effect with respect to
the grate and of such helical disposition as to contribute to
the axial propulsion of the crop material. In addition, it is
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3~
a feature of the invention to attach the crop material
engaging element to the rotor frame in such a way that it can
yield to reduce the effective diameter of the rotor when
overloaded locally with an excess flow of crop material (or a
foreign body), momentarily causing a tendency to plug the
separator. Preferably, this yielding is principally in a
plane parpendicular to the axis of rotation of the rotor.
Brief Description of the Drawinqs
Fig. 1 is a left hand side elevation of a self-propelled
combine harvester embodying the invention.
Fig. 2 is a left, front perspective view of a separator
rotor from one of the separator units of the combine
harvester.
Fig. 3 is an enlarged view of a crop-engaging element
from the rotor of Fig. 2.
Fig. 4 is a side elevation of the rotor element of Fig. 3
showing its relationship to the rokor frame.
Figs. 5 and 6 are partial views of the crop material
engaging tips of the rotor element taken approximately on
lines 5-5 and 6-6 respectively of Fig. 3.
Fig. 7 is a perspective view of an alternative crop
material engaging element of the rotor.
Fig. 8 is a cross-sectional view of a rotor embodying the
element of Fig. 7.
Fig. 9 is a perspective view of a second alternative
crop- material engaging element for the rotor.
Fig. 10 is a cross-sectional view similar to Fig. 8 of a
cross-sectional view of a rotor embodying the element of
Fig. 9.
Fig. 11 is a partial view of a rotor with a third
alternative crop-material engaging element showing its
attachment to the rotor frame.
Fig. 12 is a view similar to Fig. 8 of a cross-section of
a rotor embodying the element of Fig. 11, combined with a
generic, schematic cross-section of an axial flow rotary
separator, showing the relationship of rotor to separator
casing and helical guide vanes in the casing.
Description of_the Preferred Embodiment
The invention is embodied in a self-propelled combine
harvester shown in Fig. 1.
The combine body 10 is supported on front drive wheels 12
and steerable rear wheels 14 and controlled from an operator`s
station 16. Gathering the crop from the field and threshing
is ~y conventional components, the header in this case being a
corn head 18 delivering gathered material by way of a
feederhousa 20 to a threshing cylinder and concave 22, 24
respecti~ely. Downstream delivery from the threshing cylinder
and concave is by means of a separator feed section 26 to the
twin rotor axial flow rotary separator 28 which discharges
straw at a rear discharge 30. Separated grain is passed
downwards to return conveyors 32, 34 for delivery to a
conventional cleaning shoe 36. From the cleaning shoe, clean
grain is elevated to a grain tank 38 by a clean grain elevator
(not shown). Grain is unloaded by unloading auger assembly
40.
In the present embodiment, the separator 28 comprises two
side-by-side axial flow rotary separator units, but only one
(the left-hand) separator unit 50 is visible in Fig. 1. The
typical configuration and operation of axial flow rotary
separators with eccentrically mounted rotors and relying on
helical guide elements in the separator casing for axial
indexing is already known (see for example U.S. Patent
4,611,605, Hall et al. A brief description of their function
and operation is also given below with reference to Fig. 12.
The rotor 51 of separator unit 50, housed in separator
casing 53, is shown in some detail in Fig. 2. The rotor frame
52 consists of four parallel longitudinal tubes 54 rigidly
attached to and spaced by spacer plates 56~ The front or
divider rotor portion 58 consists of a pair of paddle
assemblies 60 in each of which a diametrical arm 62, secured
to the rotor frame 52 by lugs 64, carries at its opposite
radial extremities a paddle 66.
In the present embodiment, identical crop-engaging
material elements 72 are used in both the main feed portion 74
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and the separator portion 76 of the rotor. Each element 72 is
pivoted to the rotor frame 52 by a pivot 78 permitting it to
swing in a plane parallel to the rotor axis of rotation 80.
The downstream end of the rotor se.parator portion 76 consists
of a discharge arrangement including a pair of diametrically
opposite discharge p~ddles 82 and a circular ba~fle plate 84
fixed to the rotor frame 52 and concentric with the rotor axis
80.
The "Y" shaped crop material engaging element or finger
72, pivotally mounted to the rotor frame by the pivot
arrangement 78 and seen best in Figs. 3-6, consists of an
elongated shank 90 of square tubular section to which are
attached, preferably by arc welding, crop material engaging
arms 94, 96 respectively made from round tubing. The radial
extremities 9~, 100, respectively, of these arms are the
principal propelling portions of the element and are flattened
to create crop deflecting surfaces 102, 104, respectively, as
indicated in Figs. 5 and 6. These surfaces, 102, 104 are
angled at 30 degrees from the plane of the finger 72 (which,
in assembly, is parallel to the rotor axis 80). There is
sufficient clearance in the finger pivot 78 that rotationally
rearward deflection of the finger 72 is resisted by the finger
bearing on the frame member 54 at a bearing surface 106 of the
shank 90. The rotor is driven in a counter clockwise
direction as viewed from the upstream or inlet end of the
rotor, which is on the left in Fig. 2, the direction of
rotation being indicated by the arrows in Figs~ 2 and 4.
Thus, the rotationally leading edge of the crop deflecting
portion or surface 102 is toward the left in Fig. 4, and
engagement of the crop deflecting surface 102 with crop
material will urge the material downstream or toward the
outlet end of the separator. The downstream edge of the crop
deflecting surface 102 is on the right as viewed in Fig. 4, so
that material moves away from viewer in Fig. 4, albeit in a
spiral path, toward the separator outlet end. In Fig. 5, the
rotationally leading edge of the surface 102 is at the left,
above the reference line 80, and the rotationally trailing
~L2~3~2
edge is to the right and below the reference line 80, so that,
as the finger 72 rotates, moving upwardly in Fig. 5, the
surface 102 engages crop material and wedges it downstream or
to the right in Fig. 5.
In a first alternative embodiment of crop material
engaging element (Figs. 7 and 8), the inger 110 is made in
one piece rom a flat bar of material and has a shank portion
112 and a radially outward tip portion 114 which has opposite
crop material deflecting edges 116, 118 angled in the same way
and to about the same degrse with respect to the rotor axis of
rotation as the crop deflecting surfaces 102, 104 of the
previous embodiment. These flail-like elements are pivotably
mounted to frame members 54` by fixed lugs 120 so that the
elements may pivot about axes parallel to the axis o~ the
rotor on pivots 122.
A third embodiment of crop material engaging element,
finger 130, shown in Figs. 9 and 10, is also of the flail
type. It consists of a flat bar shank 132 carried by pivot
arrangement 134 and lugs 120` on frame members 54` of the
rotor. In this case, particular or additional angled crop
deflecting surfaces are provided by the arm 136 rigidly
attached to but inset from the end or radial tip 138 of the
shank 132.
In a fourth embodiment of crop material engaginy element
(Figs. 11 and 12), finger 140 is formed from a single rod into
a shank 142 and a generally axially extending tip 144. The
tip 144 is angled from the axial direction in the same
direction and about the same amount as the surfaces 102, 104
of the embodiment of Fig. 3. The included angle between shank
142 and tip 144 is preferably less than ninety degrees, or the
tip may be curved, so that it conforms more closely to the
curve of the separator casing. A root portion 146 of the
shank 142 is embedded in and resiliently secured in a
resilient base 148 carried in a channel 150 secured between
frame members of a rotor frame 52`.
In operation, as the combine harvester advances over the
field, gathered crop is threshed and delivered to the axial
~Z~3~Z
flow rotary separator units including left-hand unit 50. The
general operation of such a unit will be described only
briefly here, with reference to Fig. 12, which includes a
cross-sectional schematic representation of a separator unit.
The casing 160 is generally cylindrical and includes a
foraminous grate 162 in its lower half and a series of
helically disposed guide vanes ~64 in an upper quadrant of the
casing.
The rotational axis 166 of the rotor 167 is off~et
downwards from the center 168 of the casing 160 towards the
grate 162. In normal operation, crop material is propelled
through the casing 160 in a generally spiral path as a mat 169
generally in contact with the inside of the casing. Thus,
with finger-like elements 170 of the same general type (140)
as described above, because of the eccentricity, the
penetration or engagement of the fingers with the mat 169
varies as the rotor rotates. During each revolution, a crop
material engaging element 170 passes relatively close to the
grate 162 in a separating phase, for example, approximately
from a to b in Fig. 12. In this phase, separating function is
enhanced by a wiping action of the element over the grate,
encouraging separation and assisting in keeping the grate free
of accumulations of crop material. In the embodiments of
Figs. 7, 9 and 11 especially, the radial extremities of the
elements have significant axial extension to assist in this
wiping action.
In the upper half of each revolution, the crop material
engaging element 170 is largely disengaged from the mat. The
speed of rotation of the rotor is such that the material is
propelled upwards, is engaged by the guide vanes 164 and
indexed downstream and, by the action of centrifugal force, is
carried above the rotor, generally in contact with the casing
and on around to be re-engaged by the rotor elements 170. In
all of the embodiments, the angling of radially extreme
surfaces with respect to the longitudinal axis of the rotor
also deflects material so as to contribute to the total axial
indexing effect of the separator.
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The "Y" form of finger 72 shown in the separator portion
of Fig. 2 and in more detail in Figs. 3 and 4, through its
tubular walded construction, combines light weight with
strength. Its support towards its radial extremity by the
frame member 5~1 at bearing surface 106 gives it relatively
high strength for circumPerentially propelling crop material
at high rates of throughput. If required by a particular crop
flow condition, loading on the finger and hence, on the total
rotor, may be relieved by sideways retraction of the finger
pivoting about
pivot 78.
In the "flail" type elements of Figs. 7 and 9, in normal
operation, centrifugal force maintains the pivoted elements in
approximately radial extension as shown in Figs. 8 and 10.
However, in encountering an obstacle or an overload situation,
the elements may retract, swinging about their pivots in a
plane perpendicular to the axis of rotation of the rotor
effectively reducing the outside diameter of the rotor. The
particular form of the element of Fig. 9 with the arm 136
radially inset from the end of the shank 132 has advantages in
harvesting corn, the form reducing the likelihood and adverse
effect of jamming corn cobs between the tip of the element and
the grate.
The slender form of the embodiment of Fig. 11 is
advantageous in allowing the element to penetrate the crop
material mat with a minimum of compression of the mat while
the length of the "tail" or tip 144 still provides substantial
surfaces for handling crop material.
