Patent Description:
Drop pans of the above described type have been used for the purpose of evaluating grain losses during operation of the combine harvester. To assess the loss, the drop pan is used to collect a sample of the discharged straw and chaff from the combine harvester, which is then inspected for the presence of grain kernels that were not properly separated from the chaff during processing of the cut crop in within the combine harvester. The quantity of usable grain kernels in the collected sample relative to the sample size is used to gauge the effectiveness of the combine harvester's current performance. If the measured grain loss is beyond an acceptable threshold, adjustment to the operating characteristics of the combine harvester to better suit the current crop conditions can be made to improve performance and reduce losses.

UK Patent Application <CIT> discloses placement manual placement of a drop pan, thus requiring increased personnel to enable manual drop plan placement relative to a moving combine harvester. This reference also discloses a separator for separating the straw and chaff of the collected sample from the lost grain kernels contained therein. The separator features a cylindrical container with a pervious mesh screen situated below an open upper end of the container, and a fan mounted beneath the mesh screen to blow air upwardly therethrough. The collected sample of the drop pan is poured into the separator, where the airflow blows the chaff and straw through the open end of the container, leaving the grain kernels to settle atop the mesh screen.

<CIT> discloses a drop pan system in which an openable/closeable housing is bolted to the undercarriage of the combine harvester to normally store the drop pan therein, until such time as a release cable operated by the driver of the combine harvester opens the housing to drop the pan to the ground, thus avoiding the need for additional personnel.

Feiffer Consult (http://feiffer-consult. de) offers a drop pan system in which an open-bottomed housing bolted to the undercarriage of the combine harvester has electromagnets that normally hold the drop pan in a nested position inside the housing, until power to the unit is cut off to drop the pan to the ground. The system lacks a dedicated power source, instead having a power cable intended for connection to a cutter bar trolley plug found on some combine harvesters. This conveniently runs the system off the vehicle's existing power supply, but renders the system incompatible with combine harvesters that lack such a plug.

German Utility Model <CIT> addresses this problem by instead providing a power supply on the magnetically attached housing, and also provides a wireless handheld transmitter by which the electromagnets are de-energized in order to release the pan. <CIT> discloses a collecting tray that is capable of being dropped behind a harvester to catch straw and lost grains in the collecting tray to determine the amount of grain loss of the harvester; and a metal bracket that is attached to the underside of the harvester. The collection trays are held to the metal bracket by at least one electromagnet. <CIT> further discloses a radio-controlled release system that can be triggered by a hand-held transmitter to release the collection tray. The collection trays are held to the metal brackets when the current is being applied to the electromagnets, and the collection trays are released when the power is switched off to the electromagnets.

German Utility Model <CIT> omits the use of a separate housing to support the drop pan, and instead mounts a dedicated power supply and electromagnetic components on the drop pan itself to enable direct magnetic attachment thereof to the undercarriage of the combine harvester. <CIT> discloses a collecting tray that is directly magnetically held to the harvester by a holding device integrated into the collecting tray. The holding device comprises two holding elements in the form of permanent magnets which may form the core of an electromagnet. <CIT> further discloses a triggering device that includes an electric energy store, a receiver and a remote control with a transmitter. When the receiver unit receives the signal from the transmitter unit, an electrical connection can be established between the permanent magnets and the electric energy store, so that the permanent magnets can be energized and are thereby demagnetized to cause the collection trays to drop. <CIT> also discloses and alternative embodiment similar to <CIT> using electromagnets that can demagnetized by interrupting the current flow to cause the collection trays to drop from the harvester.

Similar to the latter German reference, a commercially available system marketed under the name ScherGain (http://www. ca) magnetically mounts its drop pan directly to the combine, rather than via a separate housing.

Despite the forgoing developments in the field of grain loss monitoring, there remains room for improved and alternative designs for grain loss drop pans and sample separators.

According to a first aspect of the invention, there is provided a drop pan system for collecting a discharge sample from a conveyed machine or implement according to claim <NUM>. Further preferred ambodiments are presented in the dependent claims.

Preferred embodiments of the invention will now be described in conjunction with the accompanying drawings in which:.

<FIG> and <FIG> illustrate exploded views of a drop pan system <NUM> of the present invention, which features a support housing <NUM> magnetically mountable to the undercarriage of a combine harvester to releasably carry a drop pan thereunder. The illustrated embodiment features two different sized drop pans 14A, 14B each selectively receivable by the support housing <NUM> to support the selected drop pan beneath the combine harvester. The user can select between the two differently sized pans according to different crop conditions, as described in more detail further below.

The support housing features a rectangular top wall <NUM>, and a set of four peripheral walls depending downward therefrom at respective perimeter edges of the top wall <NUM>. Of these four peripheral walls, front and rear housing walls <NUM> extend longitudinally of the rectangular top wall, and are longer than left and right housing walls <NUM> that interconnect the front and rear housing walls at the opposing ends thereof. The housing <NUM> has an open bottom of rectangular shape delimited by the lower ends of the peripheral walls in a lower plane of the housing that resides oppositely of the top wall <NUM> in parallel relation thereto. The space bound between the top wall and lower plane within the confines of the peripheral walls denotes an interior space <NUM> of the housing, which is thus closed off at the top and on all four peripheral sides, but is open at the bottom. The housing thus forms an internally hollow, open-bottomed, rectangular parallelepiped.

The interior space <NUM> of the support housing <NUM> features an elongated central enclosure <NUM> running longitudinally of the housing in parallel relation to the front and rear walls <NUM> at a longitudinal mid-plane P located centrally therebetween. Walls of this enclosure <NUM> are defined by a length of square channel attached to the underside of the housing's top wall. Front and rear enclosure walls <NUM> run parallel to the front and rear housing walls <NUM> in parallel relation thereto on respective sides of the longitudinal mid-plane P. A bottom enclosure wall <NUM> spans between the front and rear enclosure walls <NUM> at lower ends thereof in spaced and parallel relation to both the top wall <NUM> and lower plane of the housing <NUM>, whereby the bottom wall <NUM> of the enclosure <NUM> resides within the interior space <NUM> of the housing <NUM> at an intermediate elevation between the top wall <NUM> and open bottom thereof.

Electronic components of the support housing <NUM> are contained within the enclosure <NUM> between the front and rear enclosure walls <NUM> and between the top housing wall <NUM> and the bottom enclosure wall <NUM>. These electronic components include a power supply <NUM> containing or consisting of one or more rechargeable batteries, and a control module <NUM> comprising a wireless receiver connected to and powered by the power supply <NUM> within a control circuit. The enclosure <NUM> not only serves to house these electronic components in a safely enclosed environment, but also doubles as a support for components of a magnetic hold/release mechanism by which the selected drop pan can be normally maintained in a nested position disposed at least partially within the interior space <NUM> of the support housing <NUM>.

This magnetic hold/release mechanism comprises a pair of electro-permanent magnets <NUM> protruding downwardly from the bottom enclosure wall <NUM> toward, but stopping short of, the lower plane occupied by the housing's open bottom. In a known manner, an electro-permanent magnetic is operable to switch between a default holding state exerting an external magnetic field, and a release state lacking said external magnetic field. The default holding state consumes no electrical power, and thus is also referred to herein as a de-energized state of the electro-permanent magnet, while the release state requires application of DC power to an electrical coil of the electro-permanent magnet, and is therefore also referred to herein as an energized state of the electro-permanent magnet. To enable control over the state of the electro-permanent magnets, the control circuit containing the wireless transmitter is also connected to the electrical coil of each electro-permanent magnet, and is configured to switch between an "off" state electrically isolating the power supply from the coils of the electro-permanent magnets, and an "on" state electrically connecting the power supply to the coils electro-permanent magnets. The control circuit is configured to maintain the "off" state by default. In response to a command signal sent to the receiver from the transmitter of a wireless remote control <NUM>, whether operated by the driver of the combine harvester or other personnel in the proximity thereof, the control circuit momentarily switches to the "on" state, thus delivering a momentary pulse of current from the power supply to the coils of the electro-permanent magnets to switch them from the holding state to the release state. After holding the closed state of the circuit for the predetermined pulse length, the circuit automatically returns to the open state, and remains in such state until a subsequent command signal is received.

In order to be magnetically attractable to the electro-permanent magnets, the drop pans 14A, 14B may be made entirely or partially of ferromagnetic material. Another possible construction employs a non-ferromagnetic substance as its constituent material making up the majority of each pan, for example defining a floor and surrounding perimeter walls thereof, while adding smaller ferromagnetic pieces <NUM> suitably positioned on the pans for alignment with the electro-permanent magnets during nested placement of the selected drop pan into the housing <NUM>. In another example, ferromagnetic steel is used as the constituent material (e.g. aluminum, plastic, composites, etc.) making up the floor and perimeter walls, which are then painted or powder coated, and the smaller ferromagnetic pieces subsequently added to the painted/coated constituent parts are not painted or powder coated with the same material or thickness of paint or other coating t, which may detriment their magnetic attractiveness, though other chemical treatments or coatings of different material composition or thickness may used to still provide corrosion protection while being of less magnetic detriment. In the illustrated embodiment, each ferromagnetic piece <NUM> is a flat steel plate fastened to a topside of the pan's bottom floor <NUM>.

In the illustrated embodiment, the bottom floor <NUM> of each pan is of elongated rectangular shape slightly shorter and narrower than the top wall <NUM> and open bottom of the housing <NUM>, and the perimeter walls of each pan thus include longitudinally oriented front and rear pan walls <NUM> of greater length than shorter left and right pan walls <NUM> that interconnect the front and rear pan walls at opposite ends thereof. The front and rear pan walls are outwardly sloped to diverge upwardly away from the bottom floor of the pan. The left and right pan walls are trapezoidally shaped to fully close off the ends of the pan between the sloped front and rear walls thereof. Each pan has a rectangular open top delimited between the front, rear, left and right pan walls at the top ends thereof in an upper plane of the pan situated oppositely of and parallel to the bottom floor <NUM>. The open top of each pan is slightly shorter and narrower than the top wall <NUM> and open bottom of the housing <NUM>, whereby the pan, or least the open top thereof, is insertable upwardly into the housing <NUM> through the open bottom thereof for nested receipt of the pan at least partially within the interior space of the housing. Preferably the height of each pan is less than that of the housing to enable full receipt of the entire pan within the interior space <NUM> of the housing <NUM> so that the bottom floor <NUM> of the pan resides within or slightly above the lower plane of the housing <NUM> in the pans fully nested position therein.

The interior space <NUM> of the housing <NUM> features identical left and right guide brackets <NUM> situated respectively adjacent the left and right housing walls <NUM> in parallel relation thereto at short distances inward therefrom. Each guide bracket <NUM> in the illustrated embodiment is a flat plate lying parallel to its adjacent one of the left and right housing walls. A flat top edge of each guide bracket <NUM> is affixed to the underside of the housing's top wall <NUM>, while the bracket's bottom edge follows a non-linear path giving the bracket a variable-height profile from one end of the bracket to the other. Each bracket <NUM> is symmetric across the longitudinal mid-plane P, and the variable-height profile divides each bracket <NUM> into three distinguishable lobes, namely a center lobe <NUM> situated on and bisected by the mid-plane P, and two outer lobes <NUM> situated on opposite sides of the center lobe in symmetric relation to one another across the mid-plane P.

The center lobe <NUM> is trapezoidal in shape, being delimited by convergently sloped edges 48a that converge downwardly toward the mid-plane P from opposite sides thereof, and are joined together across said mid-plane by a flat central edge 48b lying parallel to the top wall <NUM> of the housing. The angle of convergence between these sloped edges 48a of the bracket's central lobe matches the angle at which the sloped front and rear walls of the smaller drop pan 14A converge downwardly toward the floor of the drop pan 14A.

Each outer lobe <NUM> is delimited between an inwardly sloped outer edge 50a that slopes downwardly toward the mid-plane P from near the front or rear housing wall <NUM>, an opposing inner edge 50b facing the nearest sloped edge 48a of the central lobe across a gap G left therebetween, and a bottom edge 50c joining together the inner and outer edge of the outer lobe in generally parallel relation to the top wall <NUM> of the housing <NUM>. The sloped outer edges 50a of the two outer lobes thus converge downwardly and symmetrically toward the mid-plane. The angle of convergence between these outer edges 50a matches the angle at which the sloped front and rear walls of the larger drop pan 14B converge downwardly toward the floor of the drop pan 14B. The distance between these outer edges 50a where they meet the bottom edges 50c of the outer lobes closely matches the bottom width of the larger drop pan 14B, as measured across the floor of the larger drop pan 14B between the bottom ends of the front and rear pan walls thereof. Likewise, the distance between the outer edges 50a of the outer guide bracket lobes near the top wall <NUM> of the housing <NUM> closely matches the top width of the larger drop pan 14B, as measured across the open top of the larger drop pan 14B between the top ends of the front and rear pan walls thereof. The bottom edges 50c of the outer lobes lie in or slightly above the same plane as the bottom ends of the electro-permanent magnets <NUM>.

The trapezoidal center lobes <NUM> of the two guide brackets <NUM> cap off the two longitudinally opposing ends of the enclosure <NUM> in which the housing's electronic components are housed. The electro-permanent magnets <NUM> are mounted to the bottom enclosure wall <NUM> and are centered on the mid-plane P at positions respectively near the two guide brackets <NUM> at the ends of the enclosure <NUM>.

Since the downwardly converging trapezoidal shape shared by the center lobes <NUM> of the two brackets <NUM> is centered on the same mid-plane P in which the electro-permanent magnets <NUM> are mounted, and the taper or convergence angle of these center lobes <NUM> matches that of the smaller drop pan 14A, the sloped edges 48a of the central lobe form guide surfaces for centering the bottom wall of the smaller drop pan on the mid-plane of the housing to thereby align the floor of the smaller drop pan 14A with the electro-permanent magnets <NUM>. Manually lifting the smaller drop pan upwardly into the open bottom of the support housing <NUM> brings the ferromagnetic pieces <NUM> on the floor <NUM> of the pan 14A into proximity with the electro-permanent magnets <NUM>. Accordingly, as long as the drop pan 14A is generally centered enough so that its open top end encompasses the bottom edge 48b of the guide bracket center lobes, the drop pan 14A will self-center itself on the midplane P as the external magnetic field exerted by the default holding state of the electro-permanent magnets <NUM> lifts the ferromagnetic pieces <NUM> on the pan floor <NUM> upwardly into contact with the bottom ends of the electro-permanent magnets <NUM>. The center lobes <NUM> of the two guide brackets <NUM> thus define an inner set of alignment guides for guided self-alignment of the smaller drop pan 14A during magnetically aided lifting of the drop pan into a nested position inside the support housing <NUM>, during which the gaps G between the center lobe <NUM> of each bracket and the outer lobes <NUM> thereof accommodate the front and rear pan walls <NUM> of the smaller pan 14A.

Similarly, since the downward convergence of the outer edges 50a of the outer lobes <NUM> of each bracket is centered on the same mid-plane P in which the electro-permanent magnets <NUM> are mounted, and matches the taper or convergence angle between the front and rear walls <NUM> of the larger drop pan 14B, the outer edges 50a of the outer lobes <NUM> of the two brackets <NUM> form guide surfaces for centering the bottom wall <NUM> of the larger drop pan 14B on the mid-plane P of the support housing <NUM> to thereby align the floor <NUM> of the larger drop pan 14B with the electro-permanent magnets <NUM>. Manually lifting the larger drop pan upwardly into the open bottom of the support housing <NUM> brings the ferromagnetic pieces <NUM> on the floor <NUM> of the pan into proximity with the electro-permanent magnets <NUM>, and as long as the drop pan is generally centered enough that its open top end encompasses the bottom edges 50c of the outer guide bracket lobes <NUM>, the drop pan will self-center itself on the midplane P as the magnetic field exerted by the default holding state of electro-permanent magnets <NUM> lifts the ferromagnetic pieces <NUM> on the pan floor <NUM> upwardly into contact with the bottom ends of the electro-permanent magnets <NUM>. The outer lobes <NUM> of the two guide brackets <NUM> thus define an outer set of alignment guides for self-alignment of the larger drop pan 14B during magnetically aided lifting thereof into the nested position inside the support housing <NUM>.

While the inner and outer alignment guides near each end of the housing are integrally seamless parts of a singular unitary bracket in the illustrated embodiment, where the gaps G open upwardly into the bracket but stop short of the mounted upper edge thereof where intact upper portions of the bracket join the different lobes together, it will be appreciated that discrete and separate lobes individually defined by respective individual pieces may be employed instead of integrally connected lobes of a common bracket. The smaller drop pan, having a lesser with than the larger drop pan, is better suited than the larger drop pan for use in long stubble conditions, for example when harvesting canola or hemp, during which relatively tall stubble is left behind in the field compared to wheat or other shorter stubble crops. In such long stubble conditions, wider drop pans have a greater likelihood of tipping over as they fall to the ground due to interference by the tall stubble. The top width of the smaller drop pan at the open top end thereof is preferably less than eight inches, and less than six inches in some embodiments. Among select embodiments, the top width may be between three and five inches, and approximately four inches in one particular embodiment. This reduced width falls more easily between adjacent stalks of tall stubble, thus reducing the likelihood of tipping, and thereby preventing loss of the collected sample.

As best shown in <FIG>, to help resist tipping, the larger drop pan 14B has out-turned wings <NUM> extending outwardly therefrom in downwardly and outwardly sloping relation from the top ends of the front and rear walls <NUM> of the pan. As shown, these wings <NUM> may be formed by integrally bent upper portions of the front and rear walls. As can be seen in <FIG> and <FIG>, the wings <NUM> preferably span a full or near entirety of the front and rear walls in the longitudinal direction of the pan. These wings help stabilize the wider pan atop or in the stubble to help reduce the chance of tipping.

To mount the support housing <NUM> to the undercarriage of a combine harvester, for example to the underside 100a of an axle housing <NUM> of the combine harvester's rear wheels <NUM> thereof as shown in <FIG>, a magnetic mounting arrangement features a pair of permanent magnets <NUM> situated above top wall <NUM> of the housing in spaced elevation therefrom atop a pair of risers <NUM>. The use of permanent magnets allows tool free mounting of the support housing to any combine harvester without any modifications thereto, and without the energy consumption associated with electromagnet retention of the housing. The use of electro-permanent magnets for the magnetic retention of the drop pan also reduces energy consumption by energizing the coils of the electro-permanent magnets only momentarily to switch from the holding state to the release state, and only in response to the command signal from the remote control when the operator wishes the release the drop pan from the moving combine harvester. Also, by using the support housing to indirectly carry the drop pan on the combine harvester, the required strength of the electro-permanent magnets is reduced, as the weight of the power supply, control circuit and electro-permanent magnets is borne by the permanent magnets <NUM> that hold the housing to the combine harvester, not by the electro-permanent magnets.

With the reduced power requirements of the system, the relatively small power supply, preferably consisting of only a singular battery, has a lesser width and depth than the smaller drop pan, and is placed in the middle area of the drop pan between the alignment brackets <NUM> in a similarly narrow enclosure <NUM> so that the enclosure the power supply contained therein fit within the footprint of either selected one of the drop pans when nested within the support housing. This helps keep the overall size of the support housing to a minimum by avoiding the need to extend the length or width of the support housing notably beyond the pan length or width in order to accommodate space for a larger battery or larger group of batteries that would have to be placed outside the footprint occupied by either drop pan. Additionally, with the drop pan, or at least the open top end thereof, situated within the interior space of the support housing, the top end of the drop pan is fully shielded by the support housing to prevent inadvertent admission of material into the drop pan before being dropped to the ground in response to the command signal from the wireless remote control.

While the forgoing embodiments are described primary in the context of testing the performance of a combine harvester, the same system be used on other conveyed machines or implements, whether self-conveyed or towed, to collect samples of material being discharged therefrom to the underlying ground surface over which the machine or implement is conveyed. For example, the system may be used to collect discharge samples from lime and compost spreaders to enable assessment and calibration of the machine's operational characteristics.

<FIG> illustrate a separator unit <NUM> operable for separating grain kernels from straw and chaff in a grain loss sample collected from a drop pan, whether from the above described drop pan system of the present invention, or another known drop pan system, for example of the types described in the forgoing background. The separator features a container <NUM> having a cylindrically shaped peripheral wall <NUM> standing upright from a flat circular floor <NUM> of the container around a full perimeter thereof to delimit an interior space of the container <NUM> above the floor <NUM> and within the confines of the peripheral wall <NUM>. Within the interior space of the container, a rechargeable battery <NUM> is mounted atop the floor <NUM> and held in a static position thereon by a battery hold-down <NUM> that resides in embracing relation over the battery and is fastened to the container floor <NUM>. A charging cable <NUM> reaches outward from the battery <NUM> to a charging port <NUM> in the peripheral wall <NUM> of the container to enable recharging of the battery <NUM> by connection to an external charger (not shown). The charging cable may incorporate suitable fuse protection between the battery and charging port.

The container features an open top end <NUM> through which the grain loss sample from the drop tray can be poured into the container. Within the interior space of the container at a spaced elevation below the open top end <NUM>, a mesh screen <NUM> divides the interior space of the container into an upper sample-receiving compartment 62a situated above the screen for receiving the grain sample, and a lower component-housing compartment 62b situated below the screen for housing operational components of the separator, including the aforementioned rechargeable power supply. A variable speed fan <NUM> forms another operational component of the separator unit, specifically a variable speed air moving device for blowing air upwardly through the mesh screen <NUM> into the upper sample-receiving compartment 62a, and onward through the open top end <NUM> of the container. The fan housing <NUM> is thus mounted below the mesh screen <NUM> and above the rechargeable battery <NUM>, with the airflow outlet 78a of the fan housing <NUM> facing upwardly toward the open end <NUM> of the container.

At the lower component-housing compartment 62b of the container <NUM>, the peripheral wall <NUM> has a series of air intake openings <NUM> situated therein at regularly spaced intervals therearound to provide a source of ambient intake air to the variable speed fan <NUM> from outside the container <NUM>. As shown, these air intake openings may be in form of elongated slots lying axially of the container <NUM> to reach upwardly toward the fan from near the container floor <NUM>. The upper portion of the peripheral wall <NUM> surrounding the upper sample-receiving compartment 62a is of solid unperforated construction. This forms a solid shroud that surrounds this upper compartment 62a and stands upright from the mesh screen <NUM> around the full circumference thereof so that all upward airflow from the fan <NUM> through the mesh screen <NUM> can only exit container through the open top end thereof <NUM>, thus lifting the freed chaff upwardly therethrough to exit the container <NUM>.

An on/off control <NUM> and a speed selection control <NUM> are mounted to the peripheral wall <NUM> of the container at the lower component-housing compartment 62b thereof and accessible at the exterior of the peripheral wall <NUM> to receive selective control input from a user concerning operation of the fan <NUM>. For such purposes, these controls <NUM>, <NUM> are thus wired in a control circuit with the rechargeable battery <NUM> and the variable speed fan <NUM> to control operation thereof. The on/off control <NUM>, for example a push button or toggle switch, is operable to selectively activate and deactivate the fan by making and breaking an electrical connection in the control circuit between the fan and the power supply, while the speed selection control <NUM>, for example featuring a rotational knob or dial, is operable to vary the rotational speed of the fan blades and thereby control the the rate of airflow forced upwardly thereby through the mesh screen, for example by adjusting an applied voltage level to the fan or adjusting the pulse width of a pulse wave modulation (PWM) signal from the battery to the fan. Such fan speed control techniques are well known and easily implemented using commercially available fan speed controllers, and thus are not described in further detail herein. Since known commercially available components can be used for the on/off and speed controls, they are illustrated only schematically and without detail.

As an alternative to an electronic speed controller of a variable speed fan, the airflow control mechanism for changing the airflow rate through the mesh screen may instead take the form of a mechanical device, for example an airflow restrictor movable into different positions of varying alignment with the air intake openings <NUM> of the container to control the admission of ambient air into the container, thus controlling the supply of intake air to the fan. This restrictor may take the form of a curved plate situated internally or externally of the container and movable into and out of a position partially obstructing the air intake openings in order to reduce the flow of intake air into the container during operation of the fan, thereby reducing the forced air flow rate through the mesh screen. In one embodiment, the restrictor has control openings therein that are laid out in similar or matching pattern to the air intake openings <NUM>, whereby the restrictor is movable around the central longitudinal axis of the container between an open position aligning the control openings with the air intake openings <NUM> to leave the airflow openings completely unobstructed for maximum intake airflow, and a partially closed position placing the control openings in overlappingly offset relation to the intake openings <NUM> to partially obstruct the air intake openings <NUM> and thereby reduce airflow into the container and through the mesh screen.

The variable speed operability of unit provides improved flexibility over the prior art, as the ability to control the operating speed of the air moving device improves compatibility with a wider variety of crops. For crops whose grain kernels are of lesser weight and/or greater surface area, a lower speed setting of the fan is selected to ensure that the grain kernels are not blown upwardly off the screen and through the open top end of the container with the chaff. Crops whose grain kernels are of greater weight and/or lesser surface area can be separated using a higher fan speed to ensure thorough separation with reduced risk of the grain kernels being discharged with the separated chaff being blown out through the open top end of the separator. Such differences in weigh concentration can be due to different crop types, different moisture levels within the same crop type, or other crop characteristics or attributes.

As shown in the cross-sectional view of <FIG>, the mesh screen <NUM> may be stretched across the central opening of a peripheral rim <NUM>, which in turn is fastened atop a screen support rim 84a having downturned moutning tabs 84b fastened to the inside of the container's peripheral wall <NUM> at spaced positions therearound. Likewise, the fan housing <NUM> may be attached to the underside of a fan support rim 86a having downturned mounting tabs 86b fastened to the inside of the container's peripheral wall <NUM> at spaced positions therearound.

As also shown in the drawings, the separator unit <NUM> may feature a bail handle <NUM> having its opposite ends pivotally pinned to the peripheral wall <NUM> of the container <NUM> at diametrically opposite points near the open top end <NUM> thereof for selective pivoting of the handle between a stowed position suspended at the side of the container, as shown in the drawings, and a deployed working position spanning diametrically across the open top end of the container at a spaced elevation thereabove. The container is thus conveniently and comfortably carried in a bucket-like fashion with the container freely swinging from the manually gripped handle in a generally upright position thereunder. While the illustrated embodiment features a cylindrical container of circular cross-section about its longitudinal axis, the cross-sectional shape of the container may be varied without departure from the present invention, and may, for example, be square in cross-section.

Claim 1:
A drop pan system (<NUM>) for a harvester, comprising:
a drop pan (14A, 14B) having a bottom floor (<NUM>) and perimeter sidewalls (<NUM>, <NUM>) defining an interior pan space with an open top end;
at least one electro-permanent magnet (<NUM>) switchable between a default de-energized state and an energized state, wherein, in the default de-energized state, the at least one electro-permanent magnet (<NUM>) is electrically isolated from an electric power supply (<NUM>) and emits an external magnetic field, and wherein, in the energized state, the least one electro-permanent magnet is electrically connected with the electric power supply (<NUM>) cancelling the external magnetic field;
characterized by:
a support housing (<NUM>) having a top wall (<NUM>) and peripheral sidewalls (<NUM>, <NUM>) which define an interior housing space (<NUM>) with an open bottom end, the support housing (<NUM>) mounted to the harvester above the ground surface with the open bottom end oriented toward the ground surface;
wherein the at least one electro-permanent magnet (<NUM>) is disposed within the interior housing space (<NUM>) of the support housing (<NUM>);
whereby the external magnetic field emitted by the at least one electro-permanent (<NUM>) while in the default de-energized state magnetically supports the drop pan (14A, 14B) from the support housing (<NUM>) with the open top end of the drop pan (14A, 14B) received within the open bottom end of the support housing (<NUM>);
whereby when the at least one electro-permanent magnet (<NUM>) is switched from the default de-energized state to the energized state, the drop pan (14A, 14B) drops from the support housing (<NUM>) to the ground surface with the open top end of the drop pan (14A, 14B) oriented away from the ground surface.