GB1561110A - Grain detection apparatus - Google Patents

Description

(54) IMPROVEMENTS RELATING TO GRAIN DETECTION APPARATUS (71) We, PROBE ENGINEERING COMPANY LIMITED, of The Avenue, Cirencester, Gloucestershire, GL7 1EL, a British Company, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to apparatus for detecting the presence of grain in combine harvesters. Grain can be distinguished from other elements and noise signals by the impact it makes on a sensor. Examples are described in our earlier Specifications Serial No. 1384882 and Application No. 30551/75, (Serial No 1552794) However, in those examples, the grain is detected when it is too late for recovery. A grain loss warning system that gives an earlier response is desirable.

One main source of loss in a combine is grain being entrained with the rubbish being discharged over the back of the strawwalkers. These walkers are designed so that in conveying the rubbish to the back of the vehicle good grain should fall through an array of teeth and into a recovery channel below. If the walker becomes overloaded, grain is still being separated from the straw at the downstream end and some gets lost with the discharged rubbish. It is therefore now intended to provide some sensing means within the walker to detect when grain is still being separated at the discharge end. If it does sense grain at this position it can be assumed that there is overloading and that grain is being lost.

According to the present invention there is provided a straw walker for a combine harvester having a channel mounted below ts for capturing grain escaping through the walker, wherein a particle detector is mounted in the well of the channel at least at the downstream end thereof, the particle detector comprising a housing incorporating a diaphragm facing upwards and substantially flush with the surrounding surface of the well, means within the housing to sense vibrations of the diaphragm and to detect grain impingements, and an outlet connection for the transmission of signals indicating such impingements.

The sensing and detecting means may include a piezoelectric crystal and amplifying and filtering means.

Preferably the housing is surrounded by an anti-vibration mounting, by which it is carried within the well of the channel below a straw walker. The housing may be of inverted cup form, with the base providing the diaphragm. The diaphragm may be flat or curved, and of various shapes in plan.

With this cup-form housing, there may be a closure member opposite the diaphragm through which the outlet connection is made.

For a better understanding of the invention one embodiment will now be described, by way of example, with reference to the accompanying drawing in which the single Figure is an axial cross-section of a grain detector according to the invention.

The detector has an inverted cup-like housing 1 with a flat circular base 2 which provides a diaphragm facing upwardly from the well of a channel 3 beneath a straw walker (not shown) of a combine harvester.

The exposed surface of the diaphragm is flush with the adjacent channel surface, and the housing has an antivibration mounting in the form of an annular rubber ring 4. A piezoelectric crystal 5 is centrally attached to the underside of the diaphragm 2 and is wired to an electronic amplifier and frequency filter assembly 6. This is concealed within the housing by a circular cover plate or closure member 7 which is centrally apertured to receive a coaxial cable socket 8. The assembly 6 is mounted on this socket and is wired thereto feed out the amplified and filtered signals picked up by the crystal 5. The socket 8 will be connected to a display and warning device (not shown) in the driver's cab which will indicate at least the presence or absence of particle impacts on the diaphragm 2 by sound and/or vision.

Grain particles falling through the strawwalker and into the well, if they impinge on the diaphragm 2, make a distinctive impact with frequencies that can be filtered out from stray noise. If the detector is placed at the downstream end of the straw-walker the presence of an output signal will indicate that grain is still being filtered and probably being lost. The display is then activated and the driver warned. Two or more detectors can be arranged along the straw walker so that a fuller picture of the grain separation can be obtained. Their outputs can be wired in parallel in one cable. Instead of providing simply a YES/NO guide to the presence of grain, the display may have meters indicating the level of grain recovery at various locations.

WHAT WE CLAIM IS: 1. A straw walker for a combine harvester having a channel mounted below it for capturing grain escaping through the walker, wherein a particle detector is mounted in the well of the channel at least at the downstream end thereof, the particle detector comprising a housing incorporating a diaphragm facing upwards and substantially flush with the surrounding surface of the well, means within the housing to sense vibrations of the diaphragm and to detect grain impingements, and an outlet connection for the transmission of signals indicating such impingements.

2. A straw walker as claimed in claim 1, wherein the sensing and detecting means includes a piezoelectric crystal and amplifying and filtering means.

3. A straw walker as claimed in claim 1 or 2, wherein the housing is surrounded by an anti-vibration mounting.

4. A straw walker as claimed in claim 1, 2 or 3, wherein the housing is of inverted cup form, with the base providing the diaphragm, and with a closure member opposite the diaphragm through which the outlet connection is made.

5. A straw walker for a combine harvester having a channel mounted below it with at least one detector substantially as hereinbefore described with reference to the accompanying drawings mounted in the well of the channel.

6. A combine harvester having a straw walker as claimed in claim 5.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims (6)

**WARNING** start of CLMS field may overlap end of DESC **. and is wired thereto feed out the amplified and filtered signals picked up by the crystal 5. The socket 8 will be connected to a display and warning device (not shown) in the driver's cab which will indicate at least the presence or absence of particle impacts on the diaphragm 2 by sound and/or vision. Grain particles falling through the strawwalker and into the well, if they impinge on the diaphragm 2, make a distinctive impact with frequencies that can be filtered out from stray noise. If the detector is placed at the downstream end of the straw-walker the presence of an output signal will indicate that grain is still being filtered and probably being lost. The display is then activated and the driver warned. Two or more detectors can be arranged along the straw walker so that a fuller picture of the grain separation can be obtained. Their outputs can be wired in parallel in one cable. Instead of providing simply a YES/NO guide to the presence of grain, the display may have meters indicating the level of grain recovery at various locations. WHAT WE CLAIM IS:

1. A straw walker for a combine harvester having a channel mounted below it for capturing grain escaping through the walker, wherein a particle detector is mounted in the well of the channel at least at the downstream end thereof, the particle detector comprising a housing incorporating a diaphragm facing upwards and substantially flush with the surrounding surface of the well, means within the housing to sense vibrations of the diaphragm and to detect grain impingements, and an outlet connection for the transmission of signals indicating such impingements.

2. A straw walker as claimed in claim 1, wherein the sensing and detecting means includes a piezoelectric crystal and amplifying and filtering means.

3. A straw walker as claimed in claim 1 or 2, wherein the housing is surrounded by an anti-vibration mounting.

4. A straw walker as claimed in claim 1, 2 or 3, wherein the housing is of inverted cup form, with the base providing the diaphragm, and with a closure member opposite the diaphragm through which the outlet connection is made.

5. A straw walker for a combine harvester having a channel mounted below it with at least one detector substantially as hereinbefore described with reference to the accompanying drawings mounted in the well of the channel.

6. A combine harvester having a straw walker as claimed in claim 5.