Note: Descriptions are shown in the official language in which they were submitted.
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TILT SENSOR AND A BIN LEVEL SENSOR USING THE TILT SENSOR
BACKGROUND OF THE INVENTION
This invention relates to a tilt sensor and more
particularly to a bin filling level sensor which includes a
tilt sensor for detecting the filling of a bin to a
predetermined required filled level.
It is generally necessary for farmers of grain or
other similar particulate crops to provide storage for the crop
in a storage bin. Necessarily the storage bins stand at a
significant height above the ground and is filled by a delivery
tube which transmits the material to the top of the bin to be
poured into the bin. In order to achieve maximum storage
within the bin it is desirable to fill the bin to the upper
most possible level. It is necessary for the farmer therefore
while filling the bin to carefully watch the filling position
so that when the maximum position is attained the filling
system can be halted without overfilling the bin or causing
spillage.
One dangerous and undesirable activity which the
farmer often has to carry out therefore is to climb the bin to
visually observe the filling level and then to estimate when
the filling should be halted. Often this requires the farmer
to rapidly climb up and down which can lead to serious
accidents.
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Various bin level sensor devices have been
provided and some of these are currently available on the
market. One device includes a float element which is mounted
upon the wall of the bin at the required maximum filling
position. The float element is intended to float on top of the
upper most level of the crop so that as the crop rises it
pushes the float element upwardly and actuates a mechanical
indicator mounted upon the bin. Such a device is relatively
inexpensive but is prone to failure in that the float device
often does not properly float up in the crop and accordingly
does not actuate the mechanical indicator.
An alternative arrangement relies upon the
pressure of the grain or other crop to push a piston
longitudinally of a sleeve with a fluid indicator being
provided between the piston and the sleeve which changes its
visual appearance as the piston is pushed forwardly.
Both of these devices have the limitations that
they must be located at a particular height on the bin and that
they are necessarily visual at a position spaced some distance
away from the farmer so that the farmer has to remain
continuously alert watching for the indication when the level
is reached.
SUMMARY OF THE INVENTION
It is one object of the present invention,
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therefore, to provide a tilt sensor.
According to the invention therefore, there is
provided a tilt sensor comprising a housing, a flexible cable
for supporting the housing such that the housing is suspended
on the cable for tilting movement of the housing, the housing
having a longitudinal axis generally vertical and longitudinal
of the cable such that the axis tilts in response to movement
of the housing, and a switch mounted in the housing and
responsive to tilting of the axis beyond a predetermined angle
from the vertical, the switch comprising a lower conductor in
the form of a concave dish transverse to the axis with a
central area of the dish lower than an annular area surrounding
the central area, an upper conductor in the form of a plate
transverse to the axis and generally overlying the lower
conductor, insulator means separating the upper and lower
conductors, means for connecting a voltage across the
conductors and a conductor element mounted on the dish so as to
be free to move across the dish from the central area to a
point on the surrounding area in response to tilting of the
dish in any direction around the axis, the conductor element
being dimensioned and arranged relative to the upper conductor
such that it is spaced from the upper conductor when resting on
the central area and is brought into contact with the upper
conductor when resting on the surrounding area whereby a
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current is conducted between the upper and lower conductors
when the housing axis is tilted beyond said predetermined
angle.
A second object of the present invention is to
provide an improved bin filling level sensor.
According to a second aspect of the invention
there is provided a bin filling level sensor comprising a tilt
sensor comprising a housing, a flexible cable for supporting
the housing such that the housing is suspended on the cable for
tilting movement of the housing, the housing having a
longitudinal axis generally vertical and longitudinal of the
cable such that the axis tilts in response to movement of the
housing, and a switch mounted in the housing and responsive to
tilting of the axis beyond a predetermined angle from the
vertical, the switch comprising a lower conductor in the form
of a concave dish transverse to the axis with a central area of
the dish lower than an annular area surrounding the central
area, an upper conductor in the form of a plate transverse to
the axis and generally overlying the lower conductor, insulator
means separating the upper and lower conductors, means for
connecting a voltage across the conductors and a conductor
element mounted on the dish so as to be free to move across the
dish from the central area to a point on the surrounding area
in response to tilting of the dish in any direction around the
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axis, the conductor element being dimensioned and arranged
relative to the upper conductor such that it is spaced from the
upper conductor when resting on the central area and is brought
into contact with the upper conductor when resting on the
surrounding area whereby a current is conducted between the
upper and lower conductors when the housing axis is tilted
beyond said predetermined angle, means for attaching the cable
to the bin at an upper part of the bin such that the housing is
suspended by the cable into the bin, means outside the bin for
supplying said voltage to the conductors and warning means
actuated by said current to provide indication to a user of the
tilting of the housing, the housing being shaped such that the
engagement with the housing of an upper level of particulate
material filling the bin causes tilting of the housing beyond
said predetermined angle.
One or more embodiments of the invention will now
be described in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
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Figure 1 is a cross sectional view through a part
of a storage bin showing a bin filling level sensing device
mounted within the binO
Figure 2 is a vertical cross sectional view
through the sensing device of Figure 1.
Figure 3 is a cross sectional view along the
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lines 3-3 of Figure 2.
Figure 4 is a top plan view of a second
embodiment of filling level sensing device incorporating the
sensor of Figure 2.
Figure 5 is a side elevational view of the
embodiment of Figure 4.
In the drawings like characters of reference
indicate corresponding parts in the different figures.
DETAILED DESCRIPTIO~
A bin for storage of crops such as grain or other
particulate materials is generally indicated at 10 and is of a
conventional nature including a bin wall 11, a floor surface 12
and a roof or cover 13. The bin shown is of the conventional
type with a flat floor 12 but the filling level sensor can also
be used with bins of the hopper bottom type.
One particular usage oE the filling level sensor
of the present invention is in an arrangement in which the bin
is provided as a hopper bottom bin for measuring a
predetermined weight of the crop to be transported. In this
situation it is necessary to fill a transportation container
such as a rail car with a predetermined weight of grain. If
the weight is exceeded, fines can be levied as a deterrent to
overloading which can of course cause damage to the rail car or
the rail system. At the same time underloading is highly
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inefficient and uneconomic.
The level sensor of the present invention can be
adjusted within the bin so as to provide an indication of the
filling to predetermined different locations within the bin
dependant upon the density of the crop concerned.
The filling sensor as shown in Figure 1 comprises
a tilt sensor generally indicated at 15, a cable 16 arranged to
support the sensor 15 within the bin, a support member 17 for
the cable, the support member 17 being attached to the bin in
fixed position while allowing the cable to be moved vertically
to locate the sensor at a predetermined height within the bin.
The system further includes a battery 18 for supplying a
voltage to the cable and a warning device 19 which is
responsive to a current passing through the cable from the
battery in dependance upon the operation of the tilt sensor 15.
The warning device 19 can be an audible type sensor such as a
buzzer or it can be a visual type sensor such as a lamp or it
can include both such indicators.
The sensor 15 is shown in more detail in Fiyure 2
and comprises an elongate housing 20 in the form of a tubular
sleeve. The tubular sleeve includes a domed lower end cap 21
mounted on the end of the sleeve that is across the sleeve in a
direction generally transverse to a longitudinal axis 22 of the
sleeve. At an upper end the sleeve is closed by an end cap 23
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again fastened to the sleeve 20 and including a central gromet
24 through which the cable 16 passes. The cable 16 is thus
held in place on the end cap 23 so that the housing can be
suspended from the cable without applying longitudinal forces
on the internal conductors of the cable as indicated at 25 and
26.
Within the housing is mounted a switch element
generally indicated at 27 including a lower conductor 28 and an
upper conductor 29. The lower conductor 28 is formed as a
metal dish with a circular outer periphery of a dimension just
to be received within the tubular sleeve 20. The dish has a
smoothly concave upper surface. In an alternative arrangement
(not shown) the dish can be substantially conical in shape
converging toward a lower most apex. In a preferred
arrangement however the dish is smoothly concave. The upper
conductor 29 forms a plate substantially coextensive with the
dish 28 and overlying the dish 28 and shaped such that it
converges toward the dish at an area surrounding a central area
of the dish. Thus the spacing between the conductors at the
central area is increased and that spacing decreases toward the
side wall of the tubùlar sleeve at all positions around the
360 angle of the tubular sleeve. Preferably the upper
conductor 29 is similarly dished to the dish 28 and is inverted
relative thereto so as to provide the most rapid approach of
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the conductors with the minimum amount of dishing of the
lowermost conductor.
On top of the lower conductor is mounted a
conductor element preferably in the form of a ball 30 which
simply can roll across the concave upper surface of the dish
28. Normally with the axis 22 vertical the bowl 30 will take a
central position. However if the axis 22 is tilted from the
vertical the bowl will move to one side to a position shown in
dotted line at 30A at which the bowl will contact both the
upper and lower conductors.
Both conductors are mounted on the tubular wall
20 and are supported thereon by an insulating gasket or spacer
member 31 which holds the conductors normally separated. The
cable conductor 26 extends to the upper conductor plate 29.
The cable conductor 25 extends past the spacer 31 to the lower
conductor dish 28 thus connecting the voltage supplied by the
cable 16 across the conductors.
Tilting of the axis 22 of the tubular body
through an angle preferably less than 45 and preferably less
than 20 causes the conductor element or bowl 30 to move from
its central position toward one side wall of the tubular sleeve
to a position sufficient to engage the upper conductor, provide
electrical connection therebetween to actuate the warning
indicator 19.
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The lower end 21 of the tubular body 20 is
rounded or slightly domed and is closed so that if it engages
the particulate material such as grain filling the bin as that
material pours into the bin, the body is slightly tilted to an
angle sufficient to cause the electrical connection. This
angle can be as small as 20 and is certainly less than 45 so
that the amount of tilt necessary is very small. It will be
appreciated that the particulate material does not act simply
to float the body but instead the body can become buried and
thus fixed if it is engaged by the materlal in a particular
way. It is necessary therefore that the amount of tilt
required to actuate the switch is relatively small and the type
of tilt switch set forth above provides this relatively small
detection angle.
In the embodiment shown in Figure 1, the cable 16
is attached to the bracket 17 so that it is substantially fixed
to the end of the bracket and includes a portion thereof and
suspended downwardly from the bracket 17. The bracket 17
includes a tubular slide member 40 able to slide longitudinally
along a vertical strut 41 mounted within the bin upon a
horizontal bracket 42 and extending downwardly from an upper
end attached adjacent an access opening 43. In this way the
tubular sleeve can be moved vertically along the strut 41 to
take up different positions depending upon the amount of
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filling of the bin that is required.
Turning now to Figures 4 and 5, there is shown an
alternative arrangement for mounting the cable 16. This
mounting arrangement comprises a mounting bracket generally
indicated at 50 including a tubular support strut 51 extending
at right angles from a base plate 52. The base plate 52
carries a magnet 53 which can be attached to the wall of the
bin at any suitable location so as to support the s~rut 51
projecting outwardly therefrom preferably in a horizontal
orientation. The use of the magnet enables the device to be
readily attachable and removable from the bin so that it does
not need to be a permanent installation as is intended with the
device as shown in Figure 1. The farmer can therefore when
intending to fill a bin climb to the access opening, insert the
tilt sensor 15 and mount the support for the cable 16 at a
suitable location at the bin. From the ground the farmer can
then detect the filling of the bin to the predetermined level
set by the position of the sensor 15.
At the end of the strut 51 is provided a vertical
tube 54 through which the cable 16 passes. The cable 16
includes a sheath 55 at the area passing through the tube 54.
The sheat 55 can be pinched by a pin 56 which is spring biased
into engagement with the sheat 5S to hold the sheath 55 and
therefore the cable at a required longitudinal position
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relative to the support tube 54. The cable carries indicating
tags 57, 58, 59 which are spaced longitudinally of the cable so
that the farmer can have a simple indication of the required
position of the sensor 15 for the particulate materials of
predetermined density.
The pin 56 is mounted upon a lever 60 which is
biased by a spring 61 into the clamping or pinching position.
The lever includes a handle 62 which allows the pin to be
retracted from its location within the tube 54 to release the
cable 16 for longitudinal sliding movement.
Since various modifications can be made in my
invention as hereinabove described, and many apparently widely
different embodiments of same made within the spirit and scope
of the claims without departing from such spirit and scope, it
is intended that all matter contained in the accompanying
specification shall be interpreted as illustrative only and not
in a limiting sense.
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