U.S. patent number 3,603,457 [Application Number 04/828,607] was granted by the patent office on 1971-09-07 for electronic product-sizing apparatus.
Invention is credited to Allan T. Flodin, John F. Flodin.
United States Patent |
3,603,457 |
Flodin , et al. |
September 7, 1971 |
ELECTRONIC PRODUCT-SIZING APPARATUS
Abstract
Articles such as crops are sized while being moved past a
photoelectric sizing station by a continuously moving conveyor. A
set of spaced sizing cells at the sizing station gauge the
dimensions of the article to emit a signal if the size and shape of
the article is within a predetermined and adjustable range.
Generation of the signal operates an ejection device to remove the
article from the conveyor.
Inventors: |
Flodin; John F. (Sunnyside,
WA), Flodin; Allan T. (Sunnyside, WA) |
Family
ID: |
25252260 |
Appl.
No.: |
04/828,607 |
Filed: |
May 28, 1969 |
Current U.S.
Class: |
209/563; 209/586;
209/549; 250/223R |
Current CPC
Class: |
B07C
5/10 (20130101); B07B 13/00 (20130101) |
Current International
Class: |
B07C
5/10 (20060101); B07B 13/00 (20060101); B07C
5/04 (20060101); B07c 005/342 () |
Field of
Search: |
;209/82,111.7,73,74,75
;250/223,224 ;356/156,157 ;250/22MX,222 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Knowles; Allen N.
Claims
What is claimed as new is as follows:
1. In combination with a conveyor moving articles past at least one
sizing station, apparatus for removing articles of a predetermined
size and shape from the conveyor including means for sensing the
presence of an article at the sizing station, pulse generating
means connected to the sensing means for producing a signal pulse
of a duration dependent upon the size, shape and speed of the
article approaching and departing from the sizing station, means
for terminating said signal pulse following departure of the
article from the sizing station, ejector means rendered operative
to displace the article from the conveyor during an ejection period
of predetermined duration, and means responsive to termination of
said signal pulse for rendering the ejector means operative.
2. The combination of claim 1 wherein said sensing means includes a
first set of spaced photoresponsive devices having sensing faces
aligned in a common plane parallel to the direction of movement of
the article, disabling means connecting said first set of
photoresponsive devices to the pulse-generating means for normally
preventing development of the signal pulse, a second set of spaced
photoresponsive devices having sensing faces aligned in said common
plane, and means connecting the second set of photoresponsive
devices to the pulse-generating means for limiting the strength of
the signal pulse.
3. The combination of claim 2 wherein the sensing means further
includes a source of radiation adapted to be blocked by the article
and detected by the photoresponsive devices, and means for
directing the radiation from said source onto the common plane
intersecting the article while at the sizing station, whereby only
articles at the sizing station having said predetermined size and
shape prevent radiation from impinging on the first set of
photoresponsive devices.
4. The combination of claim 3 wherein said second set of
photoresponsive devices are adjustably positioned relative to the
first set of photoresponsive devices.
5. The combination of claim 4 wherein said pulse generating means
includes a source of control voltage, a current control device
having power electrodes connected in series with the second set of
photoresponsive devices to the source and a control electrode
connected to the source, said first set of photoresponsive devices
being interconnected in parallel by the disabling means to the
control electrode.
6. The combination of claim 5 wherein said signal pulse terminating
means includes relay means for disconnecting the source from the
power electrodes when energized, and time delay means for
energizing the relay means in delayed response to conduction of
current through the current control device.
7. The combination of claim 6 including indicating means connected
to the ejector means and rendered operative during the entire
operational cycle.
8. The combination of claim 1 wherein said sensing means includes a
first group of cells from which radiation is blocked, during an
operational interval, by articles corresponding to shadows of
predetermined size and shape and a second group of cells exposed to
radiation during said operational interval.
9. In combination with a conveyor continuously moving articles
along a path of travel past at least one sizing station, apparatus
for gauging the size and shape of said articles at the sizing
station including a source of radiation laterally spaced from the
conveyor at the sizing station, a radiation receiving surface
spaced from said path of travel onto which a shadow is projected by
the source of radiation during movement of each of said articles at
the sizing station, a plurality of accept cells having
radiation-sensing faces in the plane of said receiving surface, a
plurality of reject cells closely spaced from said accept cells,
means responsive to covering of all of the accept cells by the
shadows of said articles during operational intervals at the sizing
station for generating signals, means responsive to covering of at
least one of the reject cells by said shadows during said
operational intervals for preventing operation of the
signal-generating means, delay means for delaying operation of the
signal generating means until each article passes the sizing
station, and delay means for delaying operation of the signal
generating means until a preceding one of the articles passes the
sizing station.
Description
This invention relates to a photoelectric sizing device
particularly useful for products such as potatoes, cucumbers,
etc.
Dimensional sizing apparatus of the photoelectric type arranged to
gauge the size and shape of an object as it is carried past a
sizing station, is well known. However, the need exists for a
relatively simple photoelectric sizing apparatus capable of being
adjusted for different products, conveyor speeds and in accordance
with different sizing tolerances.
In accordance with the present invention, the size and shape of
products continuously conveyed past a sizing station are gauged by
sizing cells and a source of light projecting a shadow onto a
surface mounting the faces of the sizing cells. A set of inside
"accept" cells when covered by the shadow of a product at the
sizing station during an operational interval, causes generation of
an accept signal if any one of a corresponding set of outside
"reject" cells are not covered by the shadow during the same
interval of time. The outside set of reject cells may be adjusted
relative to the inside set of cells in accordance with a desired
sizing tolerance. Through adjustable time delaying devices, the
signal generating circuit associated with the sizing cells may
accommodate different product size ranges and conveyor speeds. The
signal generated when an article of predetermined size and shape is
gauged, operates an ejection device to remove the product from the
conveyor.
These together with other objects and advantages which will become
subsequently apparent reside in the details of construction and
operation as more fully hereinafter described and claimed,
reference being had to the accompanying drawings forming a part
hereof, wherein like numerals refer to like parts throughout, and
in which:
FIG. 1 is a schematic front elevational view of the product sizing
arrangement associated with the present invention.
FIG. 2 is a top plan view of the arrangement shown in FIG. 1.
FIG. 3 is an electrical circuit diagram associated with the product
sizing apparatus of the present invention.
FIG. 4 is a graphical diagram illustrating the operational sequence
associated with the product sizing apparatus.
Referring now to the drawings in detail, FIG. 1 illustrates a
continuously moving conveyor 10 adapted to carry products or
articles such as potatoes 12 past one or more sizing stations
located in close laterally spaced relation to the conveyor. A
sizing head 14 is associated with each sizing station which also
has associated therewith a source of radiation such as a tungsten
filament lamp 16 disposed on one lateral side of the conveyor
opposite the side of the conveyor on which the sizing head 14 is
located. The light from the lamp 16 impinges on the sensing surface
18 of the sizing head which is disposed in a plane parallel to the
direction of travel of the conveyor.
It will be apparent from FIGS. 1 and 2, that when a product 12 is
at the sizing station, the lamp 16 will project a shadow of the
product onto the sizing surface 18. The sizing head mounts a
plurality of photoelectric sizing cells, the sensing faces of which
are disposed in the plane of the surface 18. The sizing cells
include a set of inside accept cells consisting of horizontally
spaced cells 20 and 22 for gauging a length dimension parallel to
the direction of travel of the conveyor and a cell 24 vertically
spaced above the conveyor to gauge the height dimension of the
product. If the product is within a predetermined size and shape,
the inside cells 20, 22 and 24 will during a short interval of time
be covered by the shadow of the product or disposed within its
shadow outline 26 as shown in FIG. 1. Also, during the same
interval of time the shadow of the product of predetermined size
and shape does not cover any one of a set of outside reject cells
28, 30 and 32 adjustably positioned relative to corresponding
accept cells 20, 22 and 24.
By adjusting the position of the outside reject cells, different
sizing tolerances may be accommodated. Also, the spacing between
the inside cells may be varied together with the outside reject
cells in the respective sizing heads, if more than one is utilized,
in order to remove products within different size ranges at each of
the sizing stations. The products are removed from the conveyor by
any suitable ejection device having an electromagnetically operated
solenoid element 34 as shown in FIG. 3. The ejector solenoid 34
forms part of a control circuit housed within each of the sizing
heads. By means of the circuit, a signal is generated to pulse the
solenoid 34 whenever the shadow of a product at the sizing station
covers the inside set of the cells 20, 22 and 24 but does not cover
the outside set of reject cells 28, 30 and 32. Dependent upon the
size and shape of the product and the speed of the conveyor, the
inside set of cells will be covered by the shadow of the product at
the sizing station for a predetermined exposure period 36 as
graphically depicted in FIG. 4. After a first time delay period 42,
a pulse 38 is generated having a predetermined pulse duration 40
terminating after the elapse of the exposure period 36. A second
pulse 44 is generated at the end of a second time delay period at
which time the pulse 38 is terminated and an ejection pulse 46
initiated. An operational cycle is completed at the end of the
ejection pulse 46 automatically resetting the circuit for another
operational sequence. It will therefore be apparent, that the
ejector solenoid 34 is pulsed after the product is sized as
reflected by a signal pulse 38 of a sufficiently long duration to
ensure proper spacing between cycles in order to avoid
interference.
The circuit shown in FIG. 3, includes a DC source of voltage 48
varying within plus or minus 1 percent from a 21.5 VDC value. The
positive terminal of the source 48 is connected by a fuse 50 to the
contact 52 of a double pole, single throw power switch 54 having a
second contact 56 connected by fuse 58 to an AC source of voltage
at 60. While the AC source of voltage 60 furnishes the power for
the ejector solenoid 34, the DC source of voltage 48 supplies
control voltage for generating a signal pulse under control of the
photoresponsive sizing cells as aforementioned.
The negative terminal of the DC voltage source 48 is connected
through a current-limiting resistor 62 to one terminal of each of
the cells 20, 22 and 24 and to the "off" contact 64 of a mode
selector switch 66, having an "on" contact 68 engaged with the
switch in the position illustrated in FIG. 3. In the "on" position
illustrated, the mode selector switch 66 connects the cell 24 to
the control electrode or base of an NPN-type transistor 70. The
switch 66 in the "on" position connects cells 22 and 24 to the base
of transistor 70 and is shunted by a load resistor 72 connected to
the base. Connector assembly 74 connects the cell 22 to the switch
66 and also directly connects the cell 20 to the base bypassing the
switch. Thus all three cells 20, 22 and 24 are connected in
parallel to the base. When the mode selector switch 66 is in the
"off" position engaging contact 64, the negative terminal of the DC
source 48 is connected in series with the current-limiting resistor
62 and the photocells 22 and 24 to the base of the transistor
shunted by the photocell 20. The "off" position of the switch 66 is
utilized in order to regulate the circuit as will be explained
hereafter.
The inside photocells 20, 22 and 24 control the negative reverse
bias applied by the DC source 48 to the base of transistor 70 to
normally prevent current flow between the emitter and collector
connected in series with the outside reject photocells 28, 30 and
32. The series connected reject cells are connected to a source of
positive potential from which a forward bias is applied to the base
through adjustable resistor 76 in series with a current-limiting
resistor 78. The forward bias is supplied from the positive
terminal of DC source 48 through power switch 54 and relay switch
80. When reverse bias is removed from the base, transistor 70 is
rendered conductive to conduct current and complete a relay
energizing circuit for the relay coil 86 thereby energized to close
the normally open relay switch 82.
In the normal position of the relay switch 80, the positive
terminal of the DC power source is connected through the series
connected cells 28, 30 and 32, the transistor 70 and resistor 84 to
one terminal of the relay coil 86, the other terminal being
connected to the negative terminal of the power source. When the
photocells 28, 30 and 32 are exposed to light from the lamp 16 so
as to maintain a low resistance value, and reverse bias is removed
from the base of the transistor 70 by an increase in the resistance
values of the photocells 20, 22 and 24, an energizing current pulse
will be conducted through the relay coil 86 to close the normally
opened relay switch 82. The terminals of the relay coil 86 are,
however, shunted by a time delay capacitor 88 in parallel with
resistor 90 and adjustable resistor 92. Resistor 92 is adjustable
to vary the duration of the first time delay 42 before the current
conducted by transistor 70 causes energization of the relay coil
86. Thus, the duration of the current pulse or conductive period of
transistor 70 must exceed the first time delay period 42. The speed
of the products, their sizes and irregular shapes, causes the pulse
to vary in strength and duration. The minimum pulse strength for
energizing relay coil 86 is established by the resistor 90, while a
minimum pulse duration is established by the value of capacitor 88
and the resistor 84.
Upon energization of the relay coil 86 closing the normally open
relay switch 82, the positive terminal of the DC voltage source is
connected through resistor 94 to one terminal of a second relay
coil 96, the other terminal of which is connected to the negative
terminal of the voltage source. The terminals of the relay coil 96
are shunted by a second time delay capacitor 98 in parallel with
resistor 100 and adjustable resistor 102. Thus, upon closing of the
normally open relay switch 82, an energizing circuit is completed
for the relay coil 96 to cause energization thereof after a second
time delay determined by the capacitor 98 and the setting of the
adjustable resistor 102. The resistor 100 limits the current flow
to protect relay coil 86 from high current damage.
Energization of the relay coil 96 after the second time delay,
actuates its relay switch 80 to open the energizing circuit for the
relay coil 86. When actuated, the relay switch 80 also connects the
positive terminal of the DC voltage source through a voltage
reducing resistor 104 to one terminal of a voltage isolating relay
coil 106, the other terminal of which is connected to the negative
terminal of the DC voltage source. The terminals of the relay coil
106 are shunted by a transient voltage-suppressing capacitor 108.
It will therefore be apparent that energization of the relay coil
96 occurs after a second delay of sufficient duration to insure
that the product has cleared the sizing station as diagrammed in
FIG. 4 showing the beginning of pulse 44 spaced from the exposure
period 36. Deenergization of the relay coil 86 at that time
deactivates the transistor 70 and relay so as to allow completion
of the cycle and permit the components to stabilize. Also, the
relay coil 106 is energized to initiate the ejection period.
Upon energization of the voltage-isolating relay coil 106, the
normally opened relay switch 110 associated therewith is closed to
supply triggering current from the AC voltage source 60 through
voltage reducing resistors 112 and 114 to the control electrode of
a triac 116. Energizing current will then be transmitted by the
triac from the voltage source 60 to the ejector solenoid 34.
Transient line voltage protection is provided for the triac 116 by
resistor 118 and capacitor 120 connected in series with each other
across the triac input and output terminals.
It will be appreciated that the foregoing operation occurs only if
the power switch 54 is closed connecting the neon lamp 122 across
the terminals of the AC voltage source 60 so as to provide an
indication that power is available. Another neon lamp 124 is
connected across the terminals of the ejector solenoid 34 and will
flash each time the circuit cycles or will stay on if the winding
of the solenoid 34 is open. Thus, the lamp 124 provides an
indication that a product is being sized. The ejector solenoid 34
may either control an air valve, nozzle or other electromechanical
means associated with the ejector mechanism for removing products
from the conveyor.
With the mode selector switch 66 in the "off" position engaging
contact 64, only the cell 20 will be effective to hold a reverse
bias on the base of transistor 70 until it is covered by the shadow
of the product initiating an operational cycle. Through adjustable
resistors 92 and 102, the duration of the cycle from start to the
beginning of the ejection period may be adjusted. It should be
appreciated that for this adjustment, the photocell 20 is on the
downstream side of the sizing head relative to the direction of
travel of the conveyor. It will also be apparent that the cycle
beings only if the reject cells 28, 30 and 32 are not covered by
the product shadow when the photocell 20 becomes covered by the
shadow. When the mode switch 66 is displaced to the "on" position
engaging contact 68, all of the inside photocells 20, 22 and 24
must be covered by the shadow to enable initiation of a cycle, to
completely remove the negative reverse bias from the base of the
transistor 70 which then becomes conductive to begin a signal pulse
in view of the forward bias applied thereto through relay switch 80
and resistors 76 and 78. The relay coils 86 and 96 are then
sequentially energized as aforementioned before the ejection period
is begun by energization of the relay coil 106 supplying triggering
voltage to the triac 116 operating as a power switch to conduct
current to the ejector solenoid 34. The relay-energizing pulse 44
for the relay coil 96 is of short duration sufficient to condition
the circuit for automatic reset at the end of the ejection period
or ejector solenoid pulse 46. Operation of the circuit may be
monitored by the neon lamps 122 and 124, lamp 124 indicating when
the circuit is undergoing an operational cycle.
The foregoing is considered as illustrative only of the principles
of the invention. Further, since numerous modifications and changes
will readily occur to those skilled in the art, it is not desired
to limit the invention to the exact construction and operation
shown and described, and accordingly all suitable modifications and
equivalents may be resorted to, falling within the scope of the
invention.
* * * * *