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Claims  |
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What is claimed is:
1. In a self-propelled axial flow combine having a mobile chassis mounted
on wheels, a threshing concave provided with a cooperating rotor including
a rotor shaft which extends in the longitudinal direction of the combine,
and an engine including an engine drive shaft, the combination therewith
of improved transmission means drivingly connecting said drive shaft to
said rotor shaft, said transmission means comprising a first V-belt sheave
mounted on said chassis for rotation about a fixed axis, said first sheave
is effectively a fixed sheave, means operatively connecting the drive
shaft to said first sheave in driving relationship, a gear case housing
having a forwardly projecting output shaft and a rearwardly projecting
input shaft, said output and input shafts being disposed in spaced apart
parallelism, means operatively connecting said output shaft to the rotor
shaft in driving relationship, speed change gearing connecting said input
shaft and output shaft, a second V-belt sheave mounted on said input shaft
for rotation in unison therewith, a V-belt trained around said first and
second sheaves, the second sheave is a variable diameter sheave and
includes a pair of sheave sections capable of relative axial shifting
movement toward and away from each other, and a compression spring
yieldingly urges said sheave sections toward each other in V-belt-engaging
relationship, said housing being capable of limited tilting movement about
the axis of said output shaft in order to shift said input shaft and
sheave carried thereby toward and away from said first sheave for belt
tension regulating purposes, releasable means for securing said housing in
selected positions of inclination, said engine being disposed rearwardly
of the gear case housing, and wherein the means for operatively connecting
the engine drive shaft to said first sheave includes a jackshaft on which
such first sheave is mounted, and a belt, pulley and idler arrangement
effectively extends between said engine drive shaft and the jackshaft.
2. In a harvesting combine, the combination set forth in claim 1, wherein a
fixed plate-like carrier extends transversely of the combine chassis, said
carrier being provided with a pair of oppositely disposed arcuate slots
therein which are concentric with the longitudinal axis of the output
shaft and said releasable means for securing the housing in selected
positions of inclination comprises clamping bolts which project through
said arcuate slots.
3. In a harvesting combine, the combination set forth in claim 1, whereon
the gear case housing is tiltably mounted on a frame-like support fixedly
mounted on said chassis, said support including vertical side members and
upper and lower transverse members bridging the distance between said side
members, said lower transverse member being formed with a pair of
oppositely disposed arcuate slots which are concentric with the axis of
the output shaft, said upper transverse member being formed with a third
arcuate slot which likewise is concentric with the axis of the output
shaft, and said releasable means for securing the housing in selected
positions of inclination comprises clamping bolts which project through
said arcuate slots and serve, when tightened, to secure the housing in
selected positions of inclination.
4. In a harvesting combine, the combination set forth in claim 3 including,
additionally, an elongated threaded drawbolt pivoted at one end to said
housing in the vicinity of said third arcuate slot and having a pair of
cooperating clamping nuts thereon which are effective against the opposite
sides of a fixed portion of the frame-like support to regulate the angular
position of said gear case housing.
5. In a harvesting combine having a mobile chassis mounted on drive wheels,
a threshing concave provided with a cooperating rotor including a rotor
shaft, and an engine provided with a drive shaft, the combination
therewith of improved transmission means drivingly connecting said motor
drive shaft to said rotor shaft, said transmission means comprising a
fixed diameter V-belt sheave mounted on the chassis for rotation about a
fixed axis, means operatively connecting the engine drive shaft to said
sheave in driving relationship, a gear case housing having an output shaft
and an input shaft projecting therefrom, said output and input shaft being
disposed in spaced apart parallelism, speed change gearing connecting said
input and output shafts, means operatively connecting the output shaft to
the rotor shaft in driving relationship, a variable diameter V-belt sheave
mounted on the input shaft, said latter sheave including an axially fixed
sheave section rotatable in unison with the input shaft and a freely
rotatable axially shiftable sheave section movable toward and away from
the fixed section, spring means yieldingly biasing the axially shiftable
section toward the axially fixed section and toward a condition of maximum
sheave diameter, a V-belt trained around said fixed diameter sheave and
the variable diameter sheave, and interengaging cam means effective
between the sheave sections for augmenting the biasing action of said
spring means in response to relative rotation between the sheave sections
as a result of an increase in the load applied to said output shaft, and
consequently the axially fixed sheave section, by said rotor, said housing
being capable of limited tilting movement about the axis of said output
shaft in order to shift the input shaft and sheave carried thereby toward
and away from said fixed diameter sheave for belt tension regulating
purposes, and releasable means for securing said housing in selected
positions of inclination.
6. In a harvesting combine, the combination set forth in claim 5, wherein
said combine is an axial flow combine in which the rotor shaft extends in
the longitudinal direction of the combine chassis, the engine is disposed
rearwardly of the gear case housing, the input shaft projects rearwardly
of the housing, and the output shaft projects forwardly of the housing.
7. In a harvesting combine, the combination set forth in claim 6, wherein
the means for operatively connecting the engine drive shaft to said fixed
diameter V-belt sheave includes a jackshaft on which such sheave is
mounted, and a belt pulley and idler arrangement effectively extends
between said engine drive shaft and the jackshaft.
8. In a harvesting combine, the combination set forth in claim 6, wherein a
fixed plate-like carrier extends transversely of the combine chassis said
carrier being provided with a pair of oppositely disposed arcuate slots
therein which are concentric with the longitudinal axis of the output
shaft, and said releasable means for securing the housing in selected
positions of inclination comprises clamping bolts which project through
said arcuate slots.
9. In a harvesting combine, the combination set forth in claim 6, wherein
the gear case housing is tiltably mounted on a frame-like support fixedly
mounted on the chassis, said support including vertical side members and
upper and lower transverse members bridging the distance between said side
members, said lower transverse member being formed with a pair of
oppositely disposed arcuate slots which are concentric with the axis of
the output shaft, and said upper transverse member being formed with a
third arcuate slot which likewise is concentric with the axis of the
output shaft, and said releasable means for securing the housing in
selected positions of inclination comprises clamping bolts which project
through said arcuate slots and serve to secure the housing in selected
positions of inclination.
10. In a harvesting combine, the combination set forth in claim 9
including, additionally, an elongated threaded drawbolt pivoted at one end
to said housing in the vicinity of said third arcuate slot and having a
pair of cooperating clamping nuts thereon which are effective against the
opposite sides of a fixed portion of the frame-like support to regulate
the angular position of said gear case housing.
11. In a harvesting combine, the combination set forth in claim 5
including, additionally, a first belt-installation gauge fixedly mounted
on said chassis and designed for longitudinal alignment with the rim of
said axially fixed sheave section prior to installation of the V-belt
around said fixed diameter sheave, and a second belt installation gauge
indicia on said chassis designed for longitudinal alignment with the rim
of said axially shiftable sheave section after installation of the V-belt.
12. In a harvesting combine, the combination set forth in claim 5, wherein
a belt installation gauge angle member of right angle configuration is
fixedly mounted on said chassis and includes a transversely extending arm
and a longitudinally extending arm the distal end of which is designed for
longitudinal alignment with the rim of said axially fixed sheave section
prior to installation of the V-belt around said fixed diameter and
variable diameter sheaves, and the transversely extending arm is designed
for longitudinal alignment with the rim of the axially shiftable sheave
section after installation of the V-belt around the sheave sections.
13. In an axial flow combine having a mobile chassis, a pair of
side-by-side concaves with cooperating rotors including rotor shafts, a
power source including a drive shaft, means drivingly connecting said
rotor shafts such that rotary motion from one shaft will be transmitted to
the other shaft at the same rotational speed but in the opposite
direction, transmission means drivingly connecting said drive shaft to
said one shaft, said transmission means comprising a first sheave mounted
on said chassis for rotation about a fixed axis, means operatively
connecting said drive shaft to said first sheave in driving relationship,
a gear case housing having an output shaft and an input shaft projecting
therefrom, said output and input shafts being disposed in spaced apart
parallelism, means operatively connecting said output shaft to said one
shaft in driving relationship, speed change gearing connecting said input
shaft and output shaft, a second sheave mounted on said input shaft for
rotation in unison therewith, a belt trained around said first and second
sheaves, said housing being capable of limited tilting movement about the
axis of said output shaft in order to shift said input shaft and second
sheave carried thereby toward and away from said first sheave for belt
tensioning regulating purposes, and releasable means for securing said
housing in selected positions of inclination.
14. The invention as set forth in claim 13 in which said second sheave
includes an axially fixed sheave section rotatable in unison with said
input shaft and a freely rotatable axially shiftable sheave section
movable toward and away from the fixed section, spring means yieldingly
biasing the axially shiftable section toward the axially fixed section and
toward a condition of maximum sheave diameter, a V-belt trained around
said fixed diameter sheave and the variable diameter sheave, and
interengaging cam means effective between the sheave sections for
augmenting the biasing action of said spring means in response to relative
rotation between the sheave sections as a result of an increase in the
load applied to said output shaft and consequently the axially fixed
sheave section by said rotors. |
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Claims |
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Description |
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The improved dual speed gear case mechanism comprising the present
invention has been designed for use primarily as a transmission assembly
in connection with the driving of the threshing rotor of a harvesting
combine, especially a combine of the axial flow type.
Heretofore, in connection with harvesting combines, a sudden increase in
the load imposed upon the rotor, occasioned for example by the deposition
of a large mat or quantity of the material undergoing threshing in the
combine concave, has resulted in slipping of a V-belts which are employed
in the transmission mechanisms which are employed to connect the combine
rotor to the engine, thus resulting in shortened belt life. In an effort
to overcome this difficulty, there have been devised special torque
sensitive transmissions which include a torque sensing sheave that respond
to the loads exerted thereon so that the belt diameters thereof are
automatically varied in proportion to the magnitude of the loads involved.
Such a sheave includes an axially fixed sheave section and an axially
slidable sheave section which, when moved toward the fixed section, causes
an effective increase in belt diameter. Thus, an increase in the load will
automatically cause movement of the shiftable section toward the fixed
section, thus increasing the pressure on the opposite sides of the V-belt
so as to inhibit belt slippage, while at the same time increasing the belt
diameter.
In belt drive transmissions of this type an initial and fairly critical
belt-tensioning adjustment must be made if the sheaves are to operate in
the range for which they were designed with maximum efficiency. This
initial adjustment frequently will not remain effective after a period of
use so that it becomes necessary to resort to a prolonged period of idle
time while readjustments are carried out.
The present invention is designed to overcome the above noted limitation
that is attendant upon the use of torque sensitive V-belt sheaves in the
driving transmissions of combine rotors and, toward this end it
contemplates the provision of a novel gear case mechanism by means of
which power may be transmitted from the V-belt sheave to the combine rotor
in either of two drive speed ratios, while at the same time an adjustment
of the V-belt tension may be effected at any time without necessitating
any adjustment of the individual parts of the torque sensing sheave itself
or of the mechanism associated therewith. The provision of such a gear
case mechanism constitutes the principal object of the invention.
In carrying out this object, the invention contemplates the provision of a
gear case mechanism embodying a gear case proper in the form of a housing
having speed change gearing associated therewith and from which there
projects an input shaft on which the variable diameter torque sensitive
sheave is mounted. An output shaft also projects from the housing and is
designed for connection to the combine rotor in driving relationship. The
housing is tiltably mounted for angular turning movement about the axis of
the output shaft, the input shaft being offset from the output shaft so
that by tilting the housing in one direction or the other, the input
shaft, with its torque sensitive V-belt sheave mounted thereon, may be
shifted toward and away from the axis of the counterpart driving sheave
for the torque sensitive sheave. Releasable means are provided whereby the
gear case housing may be secured in selected angular positions, thus
varying the distance between the torque sensitive sheave and its
associated counterpart sheave, thereby regulating belt tension without
necessitating any attention whatsoever to the torque sensing mechanism.
Gauge means are associated with the angularly shiftable gear case housing
for facilitating a determination of the correct inclination of the housing
to attain proper belt tension on the torque sensing V-belt sheave.
It is a further object of the present invention to provide a novel speed
change gear mechanism which makes provision for two speed change gear
ratios and which, moreover, is provided with novel detent means whereby
the gear mechanism may be operated by remote control to attain a high
speed gear ratio, a low speed gear ratio, or a neutral condition. When in
the neutral condition the gear case output shaft and the combine rotor are
free to rotate which greatly facilitates servicing of the combine rotor.
The two speed gear housing enables the combine to be used for a wide
vadiety of crops and in various crop conditions, however, some combine
users do not require this versatility and would consider this feature to
be an unwarrented expense. The same housing, shafts and bearings can be
utilized to provide a single speed gear housing having a neutral condition
by merely eliminating one of the gear sets.
Although the torque sensitive transmission is described for use with a
single rotor axial flow combine it can also be used to drive a multiple
rotor axial flow combine as well.
Other objects and advantages of the invention, not at this time enumerated,
will become readily apparent as the nature of the invention is better
understood.
In the accompanying five sheets of drawings forming a part of this
specification, three illustrative embodiment of the invention have been
shown.
FIG. 1 is a side elevational view, partly in section, of an axial flow-type
harvesting combine with a major portion of one side wall being broken away
to reveal the crop-gathering means, the crop-feeding means, the
crop-impelling means, the axial threshing and separating means, the grain
cleaning and handling means, and the residue discharge means, the view
illustrating specifically the preferred positional relationship of the
dual-speed gear case mechanism of the present invention relative to the
combine engine and rotor;
FIG. 2 is a fragmentary perspective view, entirely schematic in its
representation, further illustrating the positional relationship between
the gear case mechanism and the engine, and especially with respect to a
certain torque sensing unit which is effectively interposed between the
engine and the gear case mechanism;
FIG. 3 is a three-quarter rear perspective view, largely in section, of the
gear case mechanism, showing the input shaft thereof operatively
associated with the torque sensing unit from which it receives its
motivating power;
FIG. 4, is a rear view of the gear case mechanism;
FIG. 5, is a sectional view taken substantially on the line 5--5 of FIG. 4;
FIG. 6 is a sectional view taken substantially on the line 6--6 of FIG. 4
and showing the gear case housing only;
FIG. 7 is a fragmentary detail view, partly in elevation and partly in
section, showing a belt tension gauge which is employed in connection with
the invention;
FIG. 8 is a schematic view showing the torque sensitive transmission
driving a dual rotor axial flow combine; and
FIG. 9 is a sectional view similar to FIG. 6 showing a single speed gear
casing.
Referring now to the drawings in detail the gear case mechanism of the
present invention has been designed particularly for use in connection
with the driving of the rotor of an axial flow-type harvesting combine of
the general character shown and described in U.S. Pat. No. 3,481,342,
granted on Dec. 2, 1969 and entitled AXIAL FLOW-TYPE COMBINE. Accordingly,
such a combine is illustrated in FIG. 1 and designed in its entirety by
the reference numeral 10. The present dual-speed gear case arrangement,
which likewise is designated in its entirety by the reference numeral 12,
is shown somewhat schematically in FIGS. 1 and 2 in its correct positional
relationship with respect to the combine while the details of such gear
case arrangement are particularly shown in the remaining views of the
drawings.
The combine 10 involves in its general organization a chassis or body 22
having vertical side walls 24, the body portion being supported by a pair
of relatively large driven wheels 26 in the front region of the combine,
and a pair of steerable or dirigible wheels 28 at the rear thereof. The
combine 10 further includes an operator's platform or cab 30, a
crop-gathering header 32, a feeder 34, a grain elevator 36 from which
there extends a grain delivery chute 37, and a power source such as an
engine 38. A grain tank (not shown) is enclosed within the walls of the
body 22.
As is the case in connection with an axial flow-type combine of the
character under consideration, the axial threshing and separating means
are embodied in an elongated and generally cylindrical member 40 in the
form of a rotor casing having a rotor 42 mounted therein, the rotor being
provided with a central rotor shaft 44. The forward end of the rotor shaft
carries a vaned impeller 46. A rotor such as this is shown and described
in U.S. Pat. No. 3,982,548 granted on Sept. 28, 1976 and entitled HELICAL
ELEMENT ROTOR-AXIAL FLOW COMBINE. Other conventional components not
specifically related to the present invention, and which are more or less
schematically illustrated herein, are the blower 50, grain auger 52
leading to the aforementioned grain elevator 36, and a tailings auger 54,
these components being enclosed within a lower casing section 56 beneath
the chassis or body portion 22. The lower portion of the rotor casing 40
is made up of the usual concave 58 and a grate 60. A conveyor structure 62
having augers 64 associated therewith is disposed beneath the rotor casing
40 and receives threshed and separated grain from the concave and grate
sections 58 and 60 and discharges the grain onto a chaffer sieve 66. Such
sieve is reciprocated in a fore and aft direction so as to pass the grain
and tailings to a grain sieve 68 which also is reciprocated in order to
separate the tailings so that the grain passes through the sieve and into
the grain auger 52 while the tailings are returned to the rotor casing 40
by elevator means (not shown). A terminal beater 70 at the rear end of the
rotor casing 40 prepares the straw residue for discharge from the combine
rearwardly thereof.
The arrangement of parts thus far described is purely conventional and no
claim is made herein to any novelty associated therewith, the novelty of
the present invention residing rather in the nature of the power train
which extends from the engine 38 to the rotor shaft 44 and which includes
the aforementioned dual speed gear case mechanism 12 and which further
includes a V-belt transmission drive mechanism. While a wide variety of
V-belt transmission drive mechanisms may be associated with the gear case
12, the latter has been specifically designed for use in connection with
particular transmission mechanism in the form of a torque sensing unit 72
which is of the type shown and described in a copending application, Ser.
No. 833,776 filed on Sept. 16, 1977 and entitled TORQUE SENSING UNIT FOR
DRIVING THE ROTOR OF A HARVESTING COMBINE. Both the dual speed gear case
mechanism 12 and the torque sensing unit 72 are specially designed, each
for use in connection with the other. However, although some of the
details of the torque sensing unit are disclosed herein, particularly in
FIG. 3, such unit per se is not considered to be a part of the present
invention except insofar as its combination with the gear case arrangement
is concerned.
The torque sensing unit 72 is effectively interposed between the combine
engine 38 and the dual speed gear case 12, its function being to drive the
input shaft of the gear case mechanism by applying power thereto as is
required to transmit the necessary torque from the output shaft of the
mechanism to the combine rotor shaft 44 and overcome sudden load increases
on the combine rotor 42, while at the same time inhibiting V-belt
slippage, all in a manner and for purposes that will be made clear
subsequently when the nature of both the gear case mechanism 12 and the
torque sensing unit 72 are better understood.
Before entering into a detail description of the present gear case
mechanism 12 it is deemed pertinent to note that, as clearly shown in FIG.
3, such mechanism is intimately associated with the aforementioned torque
sensing mechanism 10, it being deemed sufficient at the present time to
point out that this intimate relationship exists largely by reason of the
fact that the gear case mechanism is provided with an input shaft 74 which
also constitutes the output shaft of the torque sensing mechanism 72, such
shaft constituting the sole connection between the two components 12 and
72. On this basis, when discussing the details of the dual speed gear box
arrangement of the present invention, the shaft 74 will be referred to as
an input shaft and, when discussing the details of the torque sensing unit
72, it will be referred to as an output shaft. When discussing the
combination which exists between the two components 72 and 12, the shaft
74 will be referred to as the common shaft. It is also deemed pertinent to
note at this point that the shaft 74 constitutes a central or axial
support for a variable diameter V-bent sheave 76 which constitutes an
input sheave for the torque sensing unit 72, such sheave cooperating with
a second sheave 78 such as appears in the schematic illustration of FIG. 2
and which is mounted on a jackshaft 79. Although as previously stated, the
torque sensing unit 72 and the dual speed gear case arrangement are
designed as counterparts, it is within the scope of the present invention
to dispense with any torque sensing facilities whatsoever and utilize the
shaft 74 for gear case input purposes by mounting a variable diameter
V-belt sheave thereon exteriorly of the gear case proper, whether such
input sheave be torque sensitive, speed sensitive or otherwise, the only
criterior being that the sheave operate in association with a counterpart
V-belt receiving sheave.
Considering now the nature of the present dual speed gear case arrangement
12, and referring particularly to FIGS. 4 and 6, such arrangement involves
in its general organization a two-part housing or gear case proper 80
which rotatably supports the input shaft 74. The housing 80 includes front
and rear walls 82 and 83, top and bottom walls 84 and 85 respectively, and
side walls 86 and 87 respectively (FIG. 4). The two parts of the housing
80 are held together by bolts 88 which appear only in FIG. 4 and have been
omitted in FIG. 6 in the interests of clarity. The terms "front" and
"rear," as used herein throughout the remainder of the specification, as
well as in the appended claims, refer to the positional relationship which
the installed gear case mechanism 12 assumes with respect to the combine
chassis 22 within which it is mounted.
The input shaft 74 is rotatably mounted in roller bearings 90 (FIG. 6) of
the cone type and which are supported in the front and rear walls 82 and
83, the shaft projecting rearwardly through a lip seal 91 in the wall 83.
An output shaft 92 is similarly supported in bearings 94 and it projects
forwardly through a lip seal 93 in the wall 82 and has a spline connection
95 (FIG. 3) with the rotor shaft 44, the spline connection operating
through a rear hub 96 associated with the rotor 40.
As best shown in FIGS. 3 and 6, the input shaft 74 has mounted thereon a
relatively large diameter rear gear 100 and a relatively small diameter
front gear 102, while the output shaft carries two compound gears 104 and
106, both such gears being freely and continuously rotatable on the output
shaft 92. The two compound gears 104 and 106 are disposed on opposite
sides of a medial raised annular splined rib 108 which is integral with
the shaft 92 and the peripheral surface of which is formed with a series
of splines. The rear compound gear 104 embodies a large diameter gear
section 110 which meshes with the gear 100 and a small diameter gear
section 112 having spline teeth thereon which are capable of longitudinal
register with the splines on the periphery of the annular rib 108 on the
shaft 92. Similarly, the forward compound gear 106 embodies a large
diameter gear section 114 which meshes with the gear 102, and a small
diameter gear section 116 which is provided with spline teeth thereon that
are capable of longitudinal register with the splines on the periphery of
the rib 108 on the shaft 92. The diameters of the raised annular rib 108
and of the spline tooth gear sections 112 and 116 are all equal, as well
as are the number of splines or spline teeth thereon and their
longitudinal disposition along the shaft 92 is such that they are arranged
in side-by-side fashion.
Encompassing the spline area offered by the spline teeth of the gear
sections 112 and 116 and the splines of the raised rib 108 is an
internally splined gear ratio shifting collar 120, the internal splines of
which are slidable longitudinally over such spline area. The longitudinal
extent of the internal splines on the collar 120 is equal to or slightly
less than longitudinal extent of the splines on the raised rib 108 so that
when the collar is in register with the rib 108 as shown in FIG. 3 there
is no side overlap, and the collar will remain motionless with the shaft
92 inasmuch as no power will be transmitted from the shaft 74 to the shaft
92 due to the fact that both compound gears 104 and 106, although
rotating, are freely mounted on the shaft 92. This position of the collar
120 is considered to be the neutral position thereof and when it is
effective no torque is applied to the combine rotor 42 so that the latter
remains stationary or can be manually rotated for servicing.
The collar 120 is formed with an external annular groove 122 therein into
which there extends an arcuate shifting fork 124 having facilities which
subsequently will be set forth whereby it may be shifted in a fore and aft
direction in order to selectively shift the collar 120 either forwardly or
rearwardly into overlapping relationship with respect to one or the other
of the gear sections 116 or 112. When the fork and collar are shifted
rearwardly, the internal splines on the collar 120 will overlap both the
splines on the rib 108 and the spline teeth on the gear section 112 of the
rearward compound gear 104 and, at this time, power will be transmitted
from the shaft 74 to the shaft 92, inasmuch as the collar 120 will
effectively couple the raised rib 108 on the shaft 92 to the constantly
rotating compound gear 104. When the fork and collar are shifted
forwardly, the internal splines on the latter will overlap both the
splines on the rib 108 and the spline teeth on the gear section 116 of the
forward compound gear 106 so that power will be transmitted from the shaft
74 to the shaft 92 because the collar 120 will effectively couple the rib
108 to the constantly rotating compound gear 106. Shifting of the collar
in the rearward direction will establish a high gear ratio drive since the
effective diameter of the gear 100 is greater than the effective diameter
of the gear 102. It will be understood that the high or low speed settings
for the gear case mechanism 12 will be effected by the operator of the
combine only at such time as the combine rotor 42 is motionless, it being
inadvisable to attempt to shift the collar 120 when there is relative
motion between the splined rib 108 and either of the spline-tooth gear
sections 112 or 116.
Referring now to FIGS. 3, 4 and 5, wherein the aforementioned collar
shifting facilities are best illustrated, these facilities include a
longitudinally shiftable gearshift rod 130, (see particularly FIG. 5)
which is slidably supported by an internal lug 132, and also by the rear
wall 83 of the housing 80. The lower region of the shifting fork 124 is
connected by a rivet 134 to an upstanding ear 136 provided on a collar
138, the latter being secured by a bolt and set collar device 140 to the
gearshift rod 130. The forward end of the rod 130 is provided with a
series of three detent notches 140 therein, such notches being designed
for electric cooperation with a spring-pressed detent ball 142. A lip seal
144 or the like is provided near the rear end of the gearshift rod 130 to
prevent escape of lubricant from the interior of the housing 80. As shown
in FIGS. 3 and 5, the rear end of the gearshift rod 130 is provided with a
flattened portion 145 which is connected by a link 146 (FIG. 3) to one end
of a gear shifting lever 148, the other end of such lever being connected
to a remote control rod 150 or the like. The lever 148 is pivoted medially
of its ends as indicated at 152 to a bracket 159 which is secured to the
rear surface of the gear case such that the shifting lever assembly
oscillates with the gear case assembly.
From the above description it will be apparent that when the gearshift rod
130 is disposed in its medial position wherein the detent ball cooperates
with the central detent notch 140, the shifting fork 124 will cause the
shifting collar 120 to assume its medial position wherein the spline teeth
thereon is wholly in register with the spline teeth on the raised rib 108,
thus causing the gear case mchanism 12 to assume its neutral condition as
previously described so that no motion is transmitted from the input shaft
74 to the output shaft 92, the combine rotor 42 thus remaining stationary.
When the gearshift rod 130 is pulled rearwardly so that the detent ball
enters the foremost detent notch 140, the high speed condition of which
the gear case mechanism is capable of assuming will obtain, the power
train involving the relatively large gear 100. When the gearshift rod 130
is pushed forwardly so that the detent ball enters the rearmost notch 140,
the low speed condition of the gear case mechanism will be attained
wherein the power train involves the relative small gear 102.
Referring now to FIG. 4, means are disclosed whereby the entire housing 80
of the gear case mechanism 12 may be regulably shifted about the axis of
the output shaft 92 which drives the rotor 42. The purpose of thus
shifting the housing 80 angularly is to shift the lateral component of
motion of the V-belt sheave 76 toward or away from its counterpart sheave
78 (FIG. 2) for belt-tightening or regulating purposes as will be
described in more detail subsequently. Before entering into a description
of the angular shifting of the gear case housing 80, it is believed that a
brief discussion of the nature of the torque sensing unit 72 is necessary
inasmuch as such angular shifting of the housing 80 at any given time will
exert a change in the relationship involved between the constituent parts
of the torque sensing unit. Accordingly, and with reference to FIG. 3, the
torque sensing unit 72, as previously stated, includes the variable
diameter input sheave 76 which is effectively mounted on the input shaft
74 of the gear case mechanism 12, such shaft constituting the output shaft
of the unit 72 so that it will be referred to as such in the following
brief description. The input sheave 76 is comprised of two sheave halves
having V-belt engaging sheave sections including an axially fixed front
section 160 and an axially shiftable rear section 162. The V-belt by means
of which the sheave 76 is driven is designated by the reference numeral
164. The sheave section 160 is secured to a radial flange 170 on the
forward end of an inner cylindrical sleeve 172 which encompasses the shaft
74 and is drivingly mounted on such shaft by a splined connection 176 at
the rear of the sleeve. The extreme rear end of the shaft 74 carries a
threaded nut and washer arrangement 178 which, in combination with the
short spline connection 176, retains the sleeve 172 in position on the
shaft 74.
The axially shiftable sheave section 162 has a rearwardly extending
generally cylindrical portion or outer sleeve 180 which is axially
shiftable but freely rotatable on the inner sleeve 172. A generally
cylindrical torque sensing cam 182 is secured by bolts to the axially
shiftable rear sheave section 162 and is formed with a pair of cam
recesses 184 in its rear circular edge. These cam recesses are designed
for cooperation with respective cam follower rollers 186 carried on a
sleeve 188 which, in turn, is pivoted for slight side-to-side swinging
movement on a hub 190 which is splined to the inner sleeve 172 so that it
rotates in unison therewith. A compression spring 192 is interposed
between the hub 190 and sheave section 162 and yieldingly urges the latter
toward the sheave section 160. Various other parts or components are
embodied in the unit 72, some of which appear in FIG. 3 and others of
which have been omitted. Among these components are various fastening
devices such as bolts or the like for holding the parts together, roller
bearings or bushings between relatively rotatable parts, and lubricating
facilities. For a more detailed understanding of the nature of the torque
sensing unit 72, reference may be had to the aforementioned application,
Ser. No. 833,776, the entire disclosure of which, insofar as it is
consistent with the present disclosure, is hereby incorporated in and made
a part of the present application by reference thereto.
In the operation of the torque sensing unit 72, assuming that the sheave
sections 160 and 162 are in their positions of close proximity to each
other so that the belt 164 rides on the outer rim regions thereof, and
assuming that the input sheave 76 is rotating in a counterclockwise
direction as seen in FIG. 3, the power which is transmitted by the belt to
the output shaft 74 of the unit 72 (input shaft of the load sensing
mechanism 12) is equally divided through two friction-derived power trains
which exist by reason of the fact that opposed axial forces are applied to
the opposite sides of the belt 164 by the two sections 160 and 162.
One-half of the power which is transmitted by the frictional drag of the
belt is conducted through the sheave section 160 directly to the shaft 74
while the other half is fed into the sheave section 162 which is free to
rotate relative to the sheave section 160 except insofar as it is
restrained by the mating surfaces of the cam 182 and its follower rollers
186 which rotate in unison with the shaft 74. Thus, the magnitude of the
compressive force (side force) on the belt 164 is the sum of the force
exerted by the spring 192 on the sheave section 162 and the force exerted
by the cam 182 on the cam follower rollers at such time as the sheave
section 162 tends to overrun the sheave section 160 incident to an
increase in the load which is encountered by the shaft 74, i.e. an
increase in the load on the combine rotor 42. Briefly stated, such an
increase in the load results in an increase in the compressive forces
acting on the edges of the belt 164, thereby tensioning the belt only to
the extent necessary to transmit the required amount of torque without
incurring belt slippage, all in a manner which is fully set forth in the
aforementioned copending application, | | |
