Patent Application
20090313962
The present invention relates to cleaning shoes for agricultural harvesters. More particularly, it relates to control systems for controlling the lateral tilt of cleaning shoes for agricultural harvesters.
Agricultural harvesters commonly use cleaning shoes to separate grain from unwanted crop material. Cleaning shoes are typically arranged as longitudinally extending troughs, often called bays, having a semi permeable floor made out of a semi permeable material such a screen, a mesh, or a plurality of slats. These bays are typically shaken fore-and-aft as air is blown up through the semi permeable bay floors to lift up and blow away lighter unwanted crop material such as straw and chaff, while permitting the grain to fall downward through the semi permeable floor into a second cleaner, commonly called a chaffer. The bay floors are typically flat, which permits gravity to spread the crop material relatively evenly across them. An even spreading of the crop material permits the air and the shaking to separate the grain from the unwanted crop material.
When an agricultural harvester is driven on a field with a slope, such that the left side of the agricultural harvester is higher than the right side (or vice versa), the bays and bay floors are tilted with respect to the ground. Such an arrangement prevents gravity from evenly distributing the crop material over the bay floors. When this occurs, crop material with entrained grain is ejected from the rear of the agricultural harvester and wasted.
One solution has been to mount the bays on pivots that permit the bays and bay floors to be tilted to the left or the right. A microcontroller is provided to monitor a vehicle tilt sensor and an actuator is provided to tilt the bays until the bay floors are level, even though the agricultural harvester itself is tilted to one side as it travels through the field. This arrangement reduces grain loss, because the bays are again level with the ground, which permits the shaking, the air, and gravity to spread the crop material out in a relatively even layer on the bay floors.
A further improvement for when the agricultural harvester has been running tilted to the left, for example, has been to not just tilt the bays back to the right until the bay floors horizontal, but to tilt the bays a few degrees farther to the right, beyond the horizontal, to spread the crop material out faster. For certain crop materials, under certain load conditions, this extra tilt reduces grain losses more effectively than purely horizontal bays.
In both of these arrangements, the angle at which the cleaning shoe is tilted is a function of the angle of tilt of the agricultural harvester and a “fudge factor” that is preprogrammed into the microcontroller that controls the tilt of the bays. Such arrangements reduce grain loss; however, this reduction is not found by looking at the grain loss directly. Such arrangements assume certain ideal responses of the crop material as it is vibrated along the bays, to the rear of the bays, and out of the agricultural harvester. What is needed is a control system for automatically tilting the bays based upon actual grain losses, and not just upon the angle of the agricultural harvester with respect to the ground and the “fudge factor.” It is an object of this invention to provide such a system.
A system for controlling the angle of a cleaning shoe of an agricultural harvester having a microcontroller connected to a grain loss sensor to determine the actual grain loss at the rear of the cleaning shoe. The microcontroller is configured to use this actual grain loss, either alone or in combination, with other factors such as the angle of the agricultural harvester and the angle of the cleaning shoe to change the cleaning shoe angle until grain loss is minimized.
In accordance with one aspect of this invention, a system for controlling the angular orientation of a cleaning shoe in an agricultural harvester is provided. The system comprises at least one grain loss detector disposed to sense grain that leaves the rear of the cleaning shoe mixed with unwanted crop material and to provide a grain loss signal. The system also comprises a vehicle tilt sensor disposed on the agricultural harvester to sense the angular orientation of the agricultural harvester. Additionally, the system comprises a cleaning shoe tilt actuator coupled to the cleaning shoe to tilt the cleaning shoe side-to-side with respect to the chassis of the agricultural harvester. Furthermore, the system comprises at least one microcontroller coupled to the at least one grain loss sensor, the vehicle tilt sensor, and the cleaning shoe tilt actuator, wherein the at least one microcontroller is configured to automatically and periodically determine the side-to-side angle of tilt of the agricultural harvester and to automatically and periodically tilt the cleaning shoe, and to use the grain loss signal provided by the grain loss detector to determine how far to tilt the cleaning shoe.
The microcontroller may be configured to use the grain loss signal to determine when to stop tilting the cleaning shoe with the cleaning shoe tilt actuator. The system may further comprise an operator input device configured to input a threshold grain loss value that the at least one microcontroller is configured to use to determine whether to start or to stop tilting the cleaning show with the cleaning shoe tilt actuator. The at least one grain loss detector may comprise at least a first and a second grain loss detector, and further wherein the microcontroller is configured to compare the grain loss indicated by the first grain loss detector with the grain loss indicated by the second grain loss detector and to tilt the cleaning shoe based at least upon this difference. In addition, the cleaning shoe may comprise a chaffer and a sieve, and the cleaning shoe tilt actuator may be coupled to the chaffer to tilt the chaffer side-to-side with respect to the chassis of the agricultural harvester.
A system 101 (see
A fan 116 is disposed to blow air upward through the semi permeable bottom of the chaffer 120 to lift unwanted crop material and carry it backward toward the rear end of the chaffer 118 where it falls onto a grain loss detector 132. The grain and crop material then falls to the ground.
The grain in the crop material that is heavy enough to fall out of the crop material falls through the semi permeable bottom of the chaffer 120 and onto sieve 122 for further cleaning. Then, the grain is carried up a grain elevator (not shown) and deposited in a grain tank 160. The grain is then unloaded through a grain auger 162.
Referring now to
The grain loss detectors 132 may be acoustic detectors that are configured to sense the impact of falling crop material on the surface of the grain loss detectors 132 before falling to the ground. The grain loss detectors 132 emit a distinctive electrical signal as grain that was not separated from the unwanted crop material in the chaffer 120 (see
The grain loss detectors 132 may be supported on the frame 150 of the agricultural harvester 100 at the rear of each bay 124. The grain loss detectors 132 are coupled to a digital microcontroller 134 which is configured to read the electrical signals from the grain loss detectors 132 and determine the amount of grain loss that is occurring.
Microcontroller 134 is also coupled to a vehicle tilt sensor 136 that may be coupled to the chassis of the agricultural harvester 100. Vehicle tilt sensor 136 produces a signal indicating the lateral (side-to-side) tilt angle of the agricultural harvester 100. Vehicle tilt sensor 136 provides this signal to microcontroller 134, which in turn is configured to process this signal and determine what the vehicle lateral tilt angle is.
A cleaning shoe tilt actuator 138 is coupled to each of the bays 124 to collectively tilt them. The cleaning shoe tilt actuator 138 is coupled to the bays 124 by a linkage 140 that tilts the bays 124 about pivots 142, 144, 146, 148 that support the bays 124. Alternatively, the cleaning shoe tilt actuator 138 could be configured to tilt the chassis of the agricultural harvester 100 with respect to the ground and thereby control the tilt of the cleaning shoe 112.
Microcontroller 134 is coupled to the cleaning shoe tilt actuator 138 to drive the cleaning shoe tilt actuator 138 and cause it to simultaneously tilt the bays 124 both left and right with respect to the agricultural harvester frame 150. The cleaning shoe tilt actuator 138 preferably has an internal position sensor 139 coupled to microcontroller 134 to indicate the tilt position of the cleaning shoe 112 (see
During normal operation, the microcontroller 134 periodically receives a signal from the vehicle tilt sensor 136 indicating the angle of tilt of the agricultural harvester 100. Occasionally this signal indicates that the agricultural harvester 100 has tilted from is previously measured position. This tilt also causes the cleaning shoe 112 (see
The operator may be optionally permitted to adjust the sensitivity of the system 101 in the following manner. The operator can select the sensitivity of the system 101 using operator input device 152, which is coupled to the microcontroller 134. The operator input device 152 may be a knob, dial, lever, switch, touch screen or button to transmit a signal indicating the operator's selection to the microcontroller 134.
Microcontroller 134 is configured to wait until the measured grain loss indicated by the grain loss detectors 132 reaches the value indicated by the operator input device 152 before it begins to adjust the angle of the cleaning shoe 112 (see
In another optional configuration, microcontroller 134 is configured to monitor the difference in grain loss between different grain loss detectors 132 in order to determine whether to tilt the cleaning shoe 112 (see
Other configurations of the above system can be made without departing from the scope of the claims. For example, more than one microcontroller may be provided to sense the detector and sensors and to drive the actuator. These more than one microcontrollers can be coupled together over a communications network such as a CAN bus to transmit information to each other to permit the overall combination of more than one microcontroller to perform the functions described herein. The cleaning shoe can have one or more bays. As little as one grain loss detector can be provided to sense the loss of grain mixed with the unwanted crop material. More than one cleaning shoe tilt actuator can be used to position the cleaning shoe. The cleaning shoe tilt actuator can be an actuator that tilts the cleaning shoe with respect to the chassis of the agricultural harvester, as shown herein, or may be an actuator configured to tilt the agricultural harvester with respect to the ground (i.e. an actuator that levels the agricultural harvester) as shown in U.S. Pat. No. 3,712,635. In this arrangement, the wheels on either side of the agricultural harvester can be selectively raised or lowered to maintain the agricultural harvester in any lateral tilt position with respect to the ground, but preferably to a substantially horizontal position in which grain loss is minimized by using the grain loss detector as described above. In this arrangement, the microcontroller will control the tilt angle of the vehicle chassis as a whole (including the bays and the cleaning shoes mounted therein) rather than controlling the tilt angle of the bays with respect to the chassis. U.S. Pat. No. 3,712,635 is incorporated herein by reference for all that it teaches.
