CA1041128A - Apparatus for detecting and dispensing articles of preselected weights suspended from shackles - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
Apparatus is disclosed for detecting and dispensing articles of preselected weights suspended from shackles being moved along a path by a conveyor line. The apparatus comprises a platform to successively support the shackles at a weighing station disposed along the path. A load cell is coupled with the platform to generate an electric signal indicative of the weight of an article carried by a shackle supported on the platform. Switching means are electrically coupled with the load cell to respond to the magnitude of signals received there-from. A solenoid is coupled with the switching means. Trip lever means are mechanically coupled with the solenoid to release an article from the shackle being weighed on the platform upon actuation of the solenoid.

Description

APPARATUS FOR DETECTING ~ND DISPENSING~ TICLES OF PBESELECTED ~ -WEIGHTS SUSPENDED ~ROM~SHACKLES

BACKG~OUND OF THE IN~ENTION
This invention reIates generally to apparatuses for detecting and dispensing articles of preselected weight suspended from shackles, and more par~icularly to apparatuses for detecting and dispensing poultry or other farm products suspended from shackles being moved along a path by a conveyor system in a processing plant.
In poultry processing plants automatic apparatus is frequently incorporated into conveyor lines to identify and dispense fowl suspended from shackles which fall within a pre- ~
selected weight range. Heretofore, such automatic apparatus has ;
typically taken the form of pivotal weight scales over which the shackles are successively brought. Movements of such scales with-in a preestablished range of distances actuates selected members of a set of microswitches. Actuation of the proper set of micro-switches generates a signal which is fed to an electrical to mechanical transducer causing a trip arm to pivot the hock engag-ing portion of the shackle being weighed thereby dispensing the bird.
The prior art methods have been noticeably lacking in certain respects. For example, the just mentioned microswitches have tended to wear out rapidly thereby creating need for frequent replacement. The scale pivot points have also tended to wear excessively which wear adversely effects both the accuracy of the scale as well as creating need for frequent pivot replacement.
The actual movement of the scale itself creates bounce which gen-erates vibrations that lead to inaccuracies in such a dynamic environment as the associated with conveyor lines.

Accordingly, it is a general object of the present - -~
inYention to provide improved apparatuses for detecting and -1- ' . ' ' ' " ' , ~,' '.

dispensing articles of preselected weight suspended from shackles movable along a path by a conveyor llne.
SUMMARY OF THE INVENTION
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The invention in one aspect comprehends an apparatus -for detecting and dispensing articles such as chickens of pre-selected weight sus-pended from shackles mova~le along a path ~y a conveyor line. The apparatus includes a platform for succes-sively supporting the shackles at a weighing station disposed along the path, and includes a load cell coupled with the platform to generate an electrical signal indicative of the weight of an article carried by a shackle supported upon the platform. Switch- ;~
ing means electrically coupled with the load cell are responsive -to the magnitude of signals received from the load cell and a solenoid is coupled with the switching means. Trip lever means are coupled with the solenoid to release an article from the shackle weighed on the platform upon actuation of the solenoid.
The switching means includes a set of switches in series circuits with the solenoid including a set of switch activating solenoids --coupled with the load cell, and circuit means for causing one of the switch activating solenoids to maintain one of the switches open a preselected period of time following generation of an electrical signal by the load cell, and to maintain the one switch closed while the electrical signal continues to be generated following the elapse of the preselected period of time.
~ Other aspects, objects and features of the invention will become apparent to those skilled in the art when the pre-ferred embodiment of the invention hereinafter detailed is review-ed in conjunction with the drawings~ -BRIEF DES~RIPTION OF THE DRAWING
Figure 1 is a perspective view of apparatus embodying principles of the present invention in one form.

~igure 2 is a side view in elevation of portions of the apparatus shown in Figure 1.

Figures 3 and 4 are end-on views taken along planes ~, 1()9~1Z~ :;
3 - 3 and 4 - 4, respectively, illustrating an operative sequence : :
of events- in weighing and dispensing a chicken in a conveyor line system.
~igure 5 is a circu;t diagram of electronic components employed in the apparatus depic~ed in Figure 1. .
' DETAILED' DES'C:R'IPTION' OF THE D~AWING : ~ :
Referring now in more detail to the drawing, there is ~
illustrated apparatus embodying principles of the present inven-tion in one preferred form comprising a centrally split platform ~:
10 mounted su~stantially coplanar between the flat portions of two centrally split ramps 12. Two opposing side walls 14 project .
upwardly from the platform in longitudinal alignment with two ramp side walls 16. . ~.
A load cell 20 is operatively mounted between a spacer 22 secured rigidly atop I-beam 24 and yoke 25. The yoke itself ~
includes two upstanding arms 26 which are secured to platform .~ .
sidewalls 14 through a platform height adjusting mechanism 28.
A solenoid 30 is mounted to I-beam 24 by means of a bifurcated solenoid support 32. Solenoid 30 includes a plunger 34 which projects downwardly beneath the solenoid and solenoid support. : . -Plunger 34 is coupled to a lever arm 35 by means of a link 36.
One end of lever arm 35 is pivotally coupled to solenoid support 32 by means of a threaded rod 38. A trip bar 40 is secured atop the other end of lever arm 35. ...
The j.ust described apparatus provides a weighing and dispensing station disposed along a path defined by a conveyor ..
line 42 from which a plurality of spaced shackles 44 are suspended by means of links 46. Each of the shackle suspension means in~
cludes a grommet 48 tightly secured about line 42 to which grommet ...: ..
a set of clamps 50 is attached. A pair of rollers 52 is rotatably :.
mounted to clamps 50 which rollers movably support shackle 44 upon the track provided by I-beam 24. A pair of fork-shaped hock .

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gripping elements 55 and a counterweight 56 are pivotally mounted to the bottom of shackIe 44 by means of pivot pin 58 beneath shackle guide bar 60. ~n L-shaped shackle trip arm 62 is press- -fitted within counterwei~ght 56 with a laterally projecting portion disposed abo~e trip lever 40. A s-econd set of rollers 66 is rotatably mounted to an upper portion o~ shackle 44 to engage the inclined portion of ramp 12.
With reference now to Figure 5 the apparatus is seen to also include eIectronic switching means coupled with load cell 10 20 and solenoid 30 which switching means is physically housed within the switch box 70 shown in Figure 1. The switching means includes two terminals 72 adapted to be connected across a con-ventionally availàble 115 VAC power source. The terminals are connected across a primary winding 74 of a stepdown transformer having a secondary winding 76 across which 10 VAC is developed once terminals 72 are connected to the source of current. This AC voltage across the transformer secondary is converted to DC
by fullwave rectification means including two diodes 78 and a ~
filtering capacitor 79, The DC voltage is delivered to load cell `-20 20 which may be provided by an Interface, Inc. load cell No.
1400 AJ-50. The output of the load cell is connected to an opera-tional amplifier 80 such as a Precision Monolithics Company model nu~er J7329.
The output of the operational amplifier is connected to a high weight limit comparator circuit, to a low weight limit comparator circuit, and to a time delay circuit. The high and low weight limit comparator circuits are similar save for reverse : .: . , connection of their relays. Each of these circuits includes a ~;
741 operational amplifier 82 connected to the output of amplifier ~0 80, and a rheostat 84 coupled to amplifiers 82. The rheostats -are manually adjustable by means of a set of dials 86 which pro-trude from the front of switch box 70 as shown in Figure 1.
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Relays are connected to the outputs of amplifiers'82 which relays include solenoids 88 electromagnetically coupled with switches 89 and 90. -~ ' Wit~ continued reference to ~igure 5 the time delay circuit is seen to include-two single shot multivibrators 92 and 94 connected in series circuit between amplifier 80 and gate 96 of a power transistor having a collector 98 connectable to the source of electric current. The transistor emitter 99 is connected ' to ground through a relay solenoid 100 which is operatively coupled '-10 with switch 102. Both switches 90 and'89 and switch 102 connect solenoid 30 in series circuit with terminals 104 which terminals are adapted to be connected across a 115 VAC source. Terminals 72 and 104 may, of course, be interconnected to extend through con- '' duits 106 from switch box 70.
With reference now to Figures 2 - 4 an operative sequence of events may be visualized. As shackles 44 approach ~ -the weighing station in the direction indicated by arrows 110 supporting chickens 108, rollers 66 are seen to be brought into engagement with ramp 12. Continued movement of conveyor line 42 causes links 46 to pivot and thereby lift rollers 66 upwardly.
This~action causes most of the weight supported by rollers 66 upon the platform to be the tare weight provided hy the shackle itsèlf plus that of the bird suspended therefrom. Continued move- ,' ment of the conveyor line causes rollers 66 to move onto platform 10~ The shackle will then proceed for a finite period of time ' , across the top surface of the platform 10 and then move onto the '~
level portion of the exit ramp 12. Continued movement of the con- "~
veyor line causes rollers 66 to descend down the exit ramp~and pivot back to a vertical orientation beneath the shackle suspen~
sion means.

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In the e~ent the ~eigh* o~ a bird supported upon the ~ `
shackle falls within a preselected weight range the previously des-cribed electronic switching means circuitry causes solenoid 30 to become energized. Energization of the solenoid causes plunger -34 to rise thereby pivoting leYer arm 35 and ~ringing trip bar 40 upwardly into engagement with shackle trip arm 62. The raising of trip arm 62 causes the hock tripping elements 55 to pivot down-wardly to the position shown in dashed lines in Figure 4 thereby permitting bird 108 to be released and fall into an unshown recep-tacle. Upon release of the bird from the hock gripping elements counterweight 56 causes the hock gripping elements S5 to return to their generally upright position as shown in Figure 3.
With reference once again to Figure 5 the manner in which the electronic switching means operates will now be described.
Load cells, as is well known, in general terms comprise a resis~
tance bridge one arm of which is sensitive to physical tension.
Thus, when the force of weight is applied to one bridge arm as tension, an imbalance in bridge resistance occurs. With DC vol-tage coupled across the bridge an output voltage imbalance is con-sequently created which is amplified by amplifier 80. An adjust-ment 81 for offsetting the output of the amplifier is provided.
This offset provides the means for zeroing or biasing the tare weight out. This adjustment allows the system to have a zero output with an unloaded shackle on platform 10. With the shackle loaded voltage is coupled with the high and low weight limit comparator circuits and to the time delay circuit.
Reference to the comparator and delay circuits shows that switches 89, 90 and 102 must all be closed in order for solenoid 30 to be coupled across terminals 104 and thereby ener-gized to cause plunger 34 to rise and a bird 108 to be dispensed.
The switches of the low comparator and time delay circuits are normally in an open position while that of the high comparator circuit is normally closed. Rheostats 84, which may be of value ~:112~

to provide up to 24,000 ohms resistance, are adj~sted to set theselected weight limits. When a ~ird of some weight is positioned upon platform 10, solenoid 88 of the low comparator will cause switch 90 associated therewith to close, if the weight is higher than the low limit. In similar ~ashion the high comparator will cause switch 89 associated therewith to remain closed once a bird of some weight is supported by platform 10. The high com-parator switch 89 will remain in closed position until a maximum point within the selected weight range is reached at which point a it will open.
The time delay of circuit is employed to prevent the switching means from becoming operative until such time as rollers 66 have travelled atop platform 10 for an appreciable distance.
The purpose of this is to prevent the switching means from reflect-ing transient weight conditions occasioned by the engagement of the rollers with the Leading edge of the platform. Preferably, the circuit is not rendered operati~e until the rollers are posi-tioned somewhere within the middle of the platform. The time delay circuitry itself is seen to comprise a first multivibrator 92 which, upon receiving a signal from amplifier 80, delivers a DC signal to a second multivibrator 94 for a finite period of time~ Upon termination of the DC signal delivered by the first multivibrator to the second multivibrator a transient electronic bounce of opposite polarity is seen by the second multivibrator.
This transient bounce causes the second multivibrator to become energized and to deliver to gate 96 of the transistor a pulse thereby gating the transistor which couples solenoid 100 to vol-tage source ~. This coupling of solenoid lQ0 to a voltage source causes switch 102 to close.
3a With time delay switch 102 closed the two comparator circuits may couple solenoid 30 across terminals 104. This will occur when a load weight fall;ng within the prescribed range is ... . .
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detected as previously descrihed. For example, should a bird weight range of between 2.Q and 3.0 pounds be selected and a bird falling within this range become positioned upon platform 10, switches 8g and 90 of the high and low camparator will be simul-taneously closed. This is so because the high comparator does not detect a bird weight in excess of three pounds and the low comparator does not detect a bird weighing less than two pounds.
A closed position of switches 90 and 89 and time delay switch 102 - ~;
serves to couple solenoid 30 across terminals 104 thereby energiz-ing the solenoid. Once the solenoid is energized and the bird dispensed from the shackle, the detected weight goes below mini-mum causing the low comparator switch 90 to open and de-energize ,: . . .
solenoid 30.
It should, of course, be understood that the just described embodiment merely illustrates principles of the inven-tion in one form. Many modific~tions may, of course, be made to the just described embodiment without departure from the spirit and scope of the invention as set forth in the following claims.

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Claims (5)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. Apparatus for detecting and dispensing articles of preselected weight suspended from shackles movable along a path by a conveyor line, comprising:
a platform for successively supporting the shackles at a weighing station disposed along the path;
a load cell coupled with said platform to generate an electrical signal indicative of the weight of an article carried by a shackle supported upon said platform;
switching means electrically coupled with said load cell and responsive to the magnitude of signals received from said load cell;
a solenoid coupled with said switching means;
trip lever means coupled with said solenoid to release an article from the shackle weighed on said platform upon actua-tion of said solenoid;
and wherein said switching means includes a set of switches in series circuits with said solenoid including a set of switch activating solenoids coupled with said load cell, and circuit means for causing one of said switch activating solenoids to maintain one of said switches open a preselected period of time following generation of an electrical signal by said load cell, and to maintain said one switch closed while said electrical signal continues to be generated following the elapse of said preselected period of time.

2. The apparatus according to claim 1 wherein said switching means includes a high comparator limit circuit including a second one of said switches in series with said solenoid and a second one of said switch activating solenoids, said high comparator limit circuit further including a manually adjustable rheostat, a differential amplifier having input terminals coupled with said rheostat and with said load cell, and an output terminal coupled with said second one of said switch activating solenoids.

3. Apparatus according to claim 2 wherein said switching means includes a low comparator limit circuit including a third one of said switches and a third one of said switch acti-vating solenoids, said low comparator limit circuit further including a manually adjustable second rheostat, and a second differential amplifier having input terminals coupled with said second rheostat and with the load cell and an output terminal coupled with said third one of said switch activating solenoids.

4. Apparatus according to claim 1 wherein said circuit means for causing one of the switch activating solenoids to main-tain one of the switches open a preselected period of time is a time delay circuit comprising said one of said switch activating solenoids and two multivibrators coupling said one of said switch activating solenoids to said load cell.

5. The apparatus according to claim 1 wherein said switching means includes second circuit means and third circuit means, said second circuit means including a second one of said switches and a second one of said switch activating solenoids and for causing said second one of said switch activating solenoids to activate said second one of said switches in response to gener-ation of an electrical signal by said load cell above a preselect-ed maximum level, and said third circuit means including a third one of said switches and a third one of said switch activating solenoids and for causing said third one of said switch activating solenoids to activate said third one of said switches in response to generation of an electrical signal by said load cell below a preselected minimal level.