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Publication numberUS2849116 A
Publication typeGrant
Publication dateAug 26, 1958
Filing dateApr 18, 1957
Priority dateApr 18, 1957
Publication numberUS 2849116 A, US 2849116A, US-A-2849116, US2849116 A, US2849116A
InventorsFried Jr William F
Original AssigneePilotlab
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Automatic weight sorting apparatus
US 2849116 A
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Description  (OCR text may contain errors)

- Aug. 26, 1958 Filed April 18. 1957 w. F. FRIED, JR 2,849,116

AUTOMATIC WEIGHT SOR'IING APPARATUS 2 Sheets-Sheet 1 FIG. 2

INVENFOR WILL/AMl-TFR/ED, JR.

his ATTORNEY Aug. 426, 1958 V w. P. FRIED, JR 2,849,116

AUTOMATIC WEIGHT SORTING APPARATUS Filed April 1 8, 1957 I 2 Sheets-Sheet 2 no v i so CYCLE INVENT OR WILLIAM E FRIED, JR.

hi 5 ATTORNEY United States Patent 2,849,116 AUTOMATIC WEIGHT SORTING APPARATUS William F. Fried, Jr., Pittsburgh, Pa., assignor to Pilotlab, Evans City, Pa., a corporation of Pennsylvania Application April 18, 1957, Serial No. 653,575

6 Claims. (Cl. 209121) This invention relates to apparatus for automatically sorting articles according to weight.

While it is essential in many industries to sort articles according to weight, the apparatus previously devised for automatic sorting, in general, has been too costly and complicated for use by relatively small packing plant-s. As a result, it is still the general practice among the smaller plants and particularly the local meat packers to sort by manual labor. However, with the widespread adoption by food stores of self-service meat departments, the demands on local meat packing facilities have so mushroomed as to create a crying need for apparatus which is both automatic and, costand maintenance-wise, within the reach of local packers. This need is especially acute in the packing of meat products such as wieners or frankfurters, which customarily are packed so many units to a package of a given minimum weight, to eliminate a major bottleneck, in at least the smaller packing plants, time-consuming manual weight sorting. It is to the elimination of this. bottleneck that the present invention is directed.

The primary object of the invention is to provide an improved apparatus for automatically sorting articles by weight which is relatively inexpensive in both initial cost and maintenance.

Another object of the invention is to provide an improved apparatus for automatically sorting articlesby weight, wherein articles are fed at spaced intervals by a moving conveyor to a sorting scale and, depending on whether their weight is within or outside predetermined limits, are discharged therefrom in one of two directions by means synchronized in operation with the feeding .of the articles by the feed conveyor.

An additional object of the invention is to provide an improved apparatus for automatically sorting articles by weight, wherein an article deposited on the platform of a scale is discharged therefrom in one of two directions, depending on its weight, by one of a pair of pneumatically actuated pushers selectively responsive to the position of the pointer of the scale relative to the beam of a lightsensitive unit.

A further object of the invention is to provide, in improved apparatus for automatically sorting articles by weight, an electrical system for selectively operating one of a pair of angularly related, pneumatically actuated pushers, whereby a pusher, once set in operation, will complete its cycle of operation unaffected by any change in the condition of the electrical selecting medium and without interference from the other pusher.

Other objects and advantages of the invention will appear hereinafter in the detailed description, be particularly pointed out in the appended claims and be illustrated.

in the accompanying drawings, in which:

Figure 1 is a fragmentary side elevational view of a preferred embodiment of the weight sorting apparatus of the present invention; 1

Figure 2 is an end elevational view of the apparatus of i 2,849,116 Patented Aug. 26, 1958 Figure 1, taken from the discharge end with the discharge conveyor removed;

Figure 3 is a plan view of the apparatus of Figure 1; and

Figure 4 is a wiring diagram of the apparatus electrical system.

Referring now in detail to the drawings, in which like reference characters designate like parts, the improved weight sorting apparatus of the present invention is particularly designed for sorting or separating units, articles or packages into two weight classifications, one of units within certain weight limits and the other of articles outside those limits and is especially suited for accepting or rejecting, according to weight and prior to packing, units or packs containing the same number of like items or produtcs, such as wieners or frankfurters.

In its preferred form, the apparatus is comprised of an endless feed conveyor 1 having a drive pulley 2 which conveniently may be at the discharge end of the conveyor, the drive pulley 2 being driven by an electric motor or other drive means 3 to which it is drivably connected through suitable reduction gearing 4. Extending transversely of the belt 5 of the feed conveyor 1 is a plurality of dividers or partitions 6 spaced uniformly longitudinally of the conveyor and each preferably formed of a plurality of transversely spaced fingers 7. Divided longitudinally by the dividers 6 into a plurality of pockets or compartments 8 of substantially equal length, the feed conveyor 1 is designed to carry in each pocket a unit or pack 9 containing a given number of the items to 'be sorted. In the case of frankfurters, while the number will vary from plant to plant, a unit will usually contain on the order of ten items or elements and the elements of each unit preferably will be contained or held together during sorting by one of a plurality of clips or trays 10 of uniform weight and made of plastic or other suitable material.

As each unit reaches the discharge end of the feed conveyor 1, it is discharged or deposited on a platform 11 of an automatic weighing scale 12. Such discharge is conveniently accomplished in the illustrated embodiment by disposing the forward flight of the feed conveyor at a higher level than the platform 11 and providing between the conveyor and the platform an inclined slide 13 down which each unit slides to the platform as it leaves its pocket on the cenveyor. So as to engage the units as they start their downward movement, the upper end of the slide 13 preferably extends substantially to the conveyor and is slotted in correspondence with the transverse spacing of the fingers 7 of the dividers 6 so as to pass the latter.

The scale 12 is of the indicating type with a column or upright 14 surmounting its base 15 to one side of the platform 11 and enclosing a pointer or indicating arm 16 oscillatable over a chart 17 to indicate the weight of a unit on the scale. Once one of the units is deposited on the platform 11, an electrical system hereinafter to be described is initiated, started or triggered by engagement with a starting switch 18 of a timing lug or cam 19 conveniently carried by the roller or pulley supporting the discharge end of the feed conveyor, here the drive roller or pulley 2. Depending on whether the weight of the particular unit on the platform is within or outside the limits for which the apparatus is set, the electrical system causes one or the other of a pair of pusher plates or pushers, disposed substantially normal to each other and termed, respectively, an accept plate 20 and a reject plate 21, to sweep or reciprocate across the platform 11 in angularly related directions toward one or another of its open sides and displace the unit therefrom, the actuated plate then returning to normal or at-rest position at one sideof the platform. Positioned, respectively, by the accept plate 20 and the reject plate 21, the accepted or within-weight units are ejected from one of the open sides of the platform 11 and the rejected or overor underweight units from another, as determined by the connection'of the separate drive means 6fth'etwo 'plates the electrical system. The sides of the platform 11 from which the two'c'lasses of units are ejected, aswell "as -the manner in which the units are handled subsequent to their ejection, are a matter of choice. 'In theillustratedembodiment, the accepted units are ejected from a side ofthe platform opposite the feed conveyor '1 onto a downwardly-inclinedaccept slide 22'by which they are delivered to a discharge conveyor 23 leading to a wrapping machine (not shown), The rejected units in turn are ejected from the side of the platform opposite the column 14 of the scale 12and directed by a downwardly-inclined reject slide 24 'onto'a conveyor (not shown) or directly into a reject bin (not shown) forfurther handling to bring the weight of the unit within the accepted limits.

Required to sweep across the platform 11 and then return to n'ormalposition, the pusher plates 20 and 21 may bereciprocated by suitable electrically responsive actuatingr'nea'ns'and preferably are reciprocated by a pair of reversible fluid pressure motor means or motors, one '25 for the accept'pla'te 20 and the other 26 for the reject plate 21, the direction of movement of the piston (not shown) of each motor being'contr'olled by a solenoid or likeelectrically-actuated valve, designated as 27 and 28 for the'accept motor 25 and reject motor 26, respectively. Depending on the clearance available, each of the pusher plates 20 and 21 may be carried directly by the piston or push rod 29 'or30'of the associated pneumatic or other fluidp'ressiiremotor means 25 and 26, as in the case of the accept p'late'20in the illustrated embodiment, or may be connected formovement with the p'istonby a connecting arm or link 3l, as in the case of the reject plate 21, the motor means in either case conveniently being mounted on the supporting frame or stand 32 of the feed conveyor 1. Disposed above the level of its" motor means 26, 'the reject plate 21 is'directly connected-to the ends of a pair of guide rods 33, the opposite end of one of which is connected'direc'tly to theconnecting arm 31 carried 'by the end of'the push r'od30' of the associated motor means 26 and the other ofwh'ich slides in and is guided by'a guide bracket 34 mounted on the base 15 of the scale 12. Attached directly to the end of its fluid pressure motor means 25,"the a'cce'pfplate 20 is guided so as to maintain it level with'respe'ct' to the scale platform 11'by a guide rod 35 spaced radially of 'the push rod 29 and sliding in or guided by'a guide'bracket 36, which in-this case is mounted on the fra'me'32'of the'feedconveyor. I As mentioned earlier, the actuation of one or the other of the pusher plates 20 and 21 'is initiated or triggered, afterone of the units'9 has been deposited on the scale platform 11 by engagement with the starting switch 18 of the timing lug 19 mounted on or carried by and extending radially of the axle of the drive rolleror pulley 2 with the starting switch 18. The longitudinal spacing between the dividers 6 is substantially equal to the circumference of the drive roller 2 so that thetiming lug 19 will make a full revolution and engage and close the starting switch 18 each time the conveyor belt moves the distance of one pocket. As'will be noted, the timing lug 19, through a bolt and slot connection37, is angularly adjustable in position eircumferentially of the drive roller 2 so as -to enable the interval between the actuation of a pusher plate and the depositing of a unit on the scale platform to be varied or adjusted to best suit the time cycle to-the type of units being sorted. The selection of-the particular pusher plate to be actuated is dependent'upon a lightresponsive or sensitive photoelectric cell 38 which is mounted on one side of the upright 14 and the light source 39 for which is mounted on the other, the cell and its light source being so mounted along the path-of'movement of the pointer 16 that the beam 'of light to the-cell will be interrupted or cut off when the pointer registers within the acceptable weight range or limits and will fall on the cell when the pointer moves outside those limits. Normally, the width of the pointer will control the acceptable limits. However, if the limits so provided are insuflicient, they may be extended by attaching a masking disc or plate (not shown) of the required area to the pointer.

The electrical systemshown in Figure 4 is particularly designed for the preferred pneumatic motor means 25 and 26, the action of each of which is controlled by the solenoid-actuated valve 27 M28, the latter, for the illustrated Bellows Company type of air motor, being readily mounted at one end of the aircylinder 40 of each motor. The valve of such "an air motor shifts under air pressure on a momentary electrical impulse to one of its two solenoids, energizing of one advancing and of the other rctracting the piston (not shown) of the motor. Although, as will be understood, the electrical system may be varied in its components as needed for the particular motor means employed to'actuate the pusher plates, the switch arrangement of the system shown in Figure 4 is especially adapted for operation of the illustrated type of air motor.

The preferred solenoid-actuated valves 27 and 28 operating on'relatively low voltage, the system, if to be connected to the usual volt, 60 cycle, A. C. current supply, includes a stepdown transformer 41 to be ungrounded output lead 42 to which is connected the starter switch 18, preferably in the form of a single contact, spring-biased, normally open switch. Beyond and connected inseries with thestarter switch is a two-contact relay 43,'one contact 44 of which leads to the advance solenoid '45 of the valve 27 of the accept plate motor 25, the other contact 46 leading'to the retract solenoid 47 of the valve 28of the reject plate motor 26. Connected to the output lead 42 in parallel with each other and the starting switch 18 is a pair of leads, one 48 to the retract solenoid 49 of thevalve 27 of the accept plate motor 25 and the other 50 to the advance solenoid 51 of the valve 28'of the reject plate motor 26. In the lead 48 in series with the windingiof the retract solenoid 49 of the accept motor valve 28 is a single contact, springbiased, normally open switch 52 and a like switch 53 is interposed in the other lead 50. A pair of like switches 54 and 55 is connected in series in the lead 56 connecting the contact 44 of the relay 43 to the advance solenoid 45 for the accept plate motor 25 and a like pair, 57 and 58, are series-connected in the lead 59 between the contact 46 and the retract solenoid 47 for the reject plate motor 26.

The relay 43 is connected in a separate circuit 60, which includes the photoelectric cell 38, which obtains its power from a suitable power source 61. Current flowing through the circuit 60 when the photoelectric cell 38 is made conducting by the'beam from the light source 39 falling on the cell, after amplification by the amplifier 62, energizes the solenoid 63 of the relay 43 pulling its switch" arm 64 against the force of its spring 65 into contact with the contact 46 leading to the retract solenoid 47 for the reject plate '21. Conversely, when the photocell is made non-conducting by breaking or interruption'of its light beam by the pointer 16, the switch arm-64 makes contact with the contact 44 to the advance solenoid 45 for the accept plate 20. 'The remaining component of the system is a manually operable switch 66 wired-in parallel with the starting switch 18 and in series with the switch arm 64 of the relay 43.

The operation of the system is as follows. Responsive to-and energized and deenergized on'conductance and non-conductance,respectively, of the photocell 38, the relay 43, if the particular unit deposited on the scale platform 11 is underor overweight, will connect the lead 59 to the retract solenoid 47 for the reject plate motor 26 to the normally open contact 67 of the starter switch 18. Consequently, on subsequent'closing of the starter switch,

the retract solenoid 47 will be energized and the reject plate 21, which in the illustrated embodiment is so arranged as to advance on the retract stroke of its motor 26, will advance and eject the unit 9 from the platform 11 onto the reject slide 24. While the reject plate is so advancing, the timing lug 19 will disengage the starter switch 18, enabling the latter to open and breaking the circuit to the output lead 42 from the transformer 41. However, the retract stroke of the reject motor 26 will continue, since dependent only for initiation on energization of its retract solenoid 47. As the reject plate 21 reaches the end of its advance, the plate itself or a member carried by or movable with it, engages and closes the switch 53, completing the circuit from the transformer 41 to and energizing the advance solenoid 51 of the reject motor 26. Thereupon, the reject motor will reverse and retract the reject plate 21 to initial position at the side of the platform 11 occupied by the upright 14.

The accept plate 20 has a corresponding cycle, being actuated on closing of the starter switch 18 when the relay 43 is deenergized and its switch arm 64 in contact with the contact 44 by virtue of interruption of the beam to the photocell 38 by the pointer 16. As in the case of the motor 26 of the reject plate 21, that 25 of the accept plate 20 continues its advance stroke after the starter switch 18 has opened, in this case advancing the accept plate across the platform 11 to eject the withinweight-limit unit 9 down the accept slide 22 to the dis charge conveyor 23. At the end of the advance of the accept plate 20, the switch 52 to the retract solenoid 49 for its motor 25 is engaged and momentarily closed, energizing the retract solenoid 49 and reversing the motor to retract the accept plate to its initial position.

The sorting mechanism continues to operate selectively in the above manner as the units 9 are deposited sequentially on the scale platform 11 by the feed conveyor 1, accepting or rejecting each unit depending on whether the pointer 16 registers within or outside the acceptable weight limits. During such operation, completion of the cycle of either of the pusher plates 20 and 21, once initiated, without interference from the other plate, is ensured by the switches 54, 55, 57 and 48. One pair of these switches, one 54 in the lead 56 to the advance solenoid 45 of the accept plate motor 25 and the other 57 in the lead 59 to the retract solenoid 47 of the reject plate motor 26, is positioned to be engaged and closed by the accept plate 20 when in its initial position and the other pair, consisting of the switches 55 and 58, is engaged and closed by the reject plate 21 when in its initial position. As a result, when either of the pusher plates moves away from its initial position on the start of its cycle, the circuits from the starter switch 18 to the solenoids responsible for initiating the advance movements of both plates are broken and not again restored until the actuated plate has completed its cycle. Thus, the selective operation of a pusher plate, once initiated, will be unaffected by any shift in the position of the pointer 16 relative to the beam to the photocell 38 and cannot be interfered with by the other plate, the latter being held during that time in its at-rest position. So as to minimize the force required to close the several switches and, in the case of the switches 54, 55, 57 and 48, to hold these switches closed in pairs when one or both of the pusher plates 20 and 21 are at rest, the several single contact switches employed in the system preferably are micro-switches, and the manually operated switch 66 may be of the same type. The switch 66 is provided to restart the cycle of the selected pusher plate should it become jammed for some reason after the initiation of its cycle.

From the above detailed description, it will be apparent that there has been provided an improved automatic weight sorting apparatus which is relatively simple and inexpensive in both its mechanical and electrical components and is practically trouble-free in operation. It should be understood that the described and disclosed embodiment is 6 merely exemplary of the invention and that all modifications are intended to be included which do not depart from either the spirit of the invention or the scope of the appended claims.

Having described my invention, I claim:

1. Weight sorting apparatus comprising an automatic scale having a platform and a pointer, a feed conveyor divided longitudinally into a plurality of pockets of substantially equal length each for conveying one of the units to be sorted to said platform, a pair of reciprocable pusher means disposed substantially normal to each other and positioned to sweep across said platform and eject a unit therefrom in one of two directions, motor means for reciprocating each of said pusher means, photosensitive' means responsive to the position of said pointer for selecting the pusher means to be actuated in accordance with whether the particular unit on the platform is within or outside acceptable weight limits, and means synchronized with said feed conveyor for initiating actuation of the selected pusher means on deposit of a unit on said platform.

2. Weight sorting apparatus comprising an automatic scale having a platform and a pointer, a feed conveyor divided longitudinally into a plurality of pockets of substantially equal length each for conveying one of the units to be sorted to said platform, a plurality of pusher means reciprocable in angularly related directions and normally positioned at sides of said platform, motor means connected to each of said pusher means for cyclically moving the connected pusher means from and to normal position across said platform and ejecting a unit on said platform therefrom in one of a plurality of directions depending on its weight, photosensitive means responsive to the position of said pointer for selecting the pusher means to be actuated in accordance with whether the particular unit on the platform is within or outside acceptable weight limits, and means synchronized with said feed conveyor for initiating actuation of the selected pusher means on deposit of a unit on said platform.

3. Weight sorting apparatus comprising an automatic scale having a platform and a pointer, a feed conveyor divided longitudinally into a plurality of pockets of substantially equal length each for conveying one of the units to be sorted to said platform, a plurality of pusher means reciprocable in angularly related directions and normally positioned at sides of said platform, motor means connected to each of said pusher means for cyclically moving the connected pusher means from and to normal position across said platform and ejecting a unit on said platform therefrom in one of a plurality of directions depending on its weight, photosensitive means responsive to the position of said pointer for selecting the pusher means to be actuated in accordance with whether the particular unit on the platform is within or outside acceptable weight limits, and rotary means synchronized in movement with said conveyor for initiating actuation of the selected pusher means on deposit of a unit on said platform, said rotary means being angularly adjustable for varying the interval between deposit of each unit and initiation of said actuation.

4. Weight sorting apparatus comprising an automatic scale having a platform and a pointer, a feed conveyor divided longitudinally into a plurality of pockets of substantially equal length each for conveying one of the units to be sorted to said platform, a pair of reciprocable pusher means normally positioned at sides of said platform, said pusher means being disposed substantially normal to each other and adapted to sweep across said platform and eject a unit therefrom in one of two directions, electrically controlled motor means for reciprocating each of said pusher means, photosensitive means responsive to the position of said pointer for selecting the pusher means to be actuated in accordance with whether the particular unit on the platform is within or outside acceptable weight limits, means synchronized with said feed conveyor for initiating actuation of the selected pusher means on deposit of a unit on said platform, and normally open switch means positioned to be closed by each of said pusher means at the end of its advance for reversing the associated electrically controlled motor means and retracting said pusher means to-normal position.

5. Weight sorting apparatus comprising an automatic scale having a platform and a pointer, a 'feed conveyor divided longitudinally into a plurality of pockets of substantially equal length each for conveying one of the units to be sorted-to said platform, a pair of reciprocable pusher means disposed substantially normal to each other and positioned to sweep across said platform and eject a unit therefrom in one of two directions, electrically controlled motor means for reciprocating each of said pusher means, photosensitive means responsive to the position of said pointer for selecting the pusher means to be actuated in accordance with whether the particular unit on the platform is within or outside acceptable weight limits, rotary means synchronized in movement with said feed conveyor, a normally open starter switch positioned to be engaged and closed by said rotary means as each unit is deposited on said platform for initiating advance of the selected pusher means, normally open switch means positioned to be closed by each of said pusher means at the end of its advance for reversing the associated motor means and retracting the selected pusher means to normal position, and switch means engagedand closed by each of said pusher means in the normal position thereof and opening on release therefrom for breaking the electrical circuits to both of said pusher means during the advance of one of said pusher means.

6. Weight sorting apparatus comprising an automatic scale having a platform and a weight-registering pointer, a feed conveyor divided longitudinally into a plurality of pockets of substantially equal length and disposed above said platform for delivering one of a plurality of units .to be sorted from each of said pockets to said platform, a downwardly'inclin'ed slide atthe discharge end of said feed conveyor for directing each of said units onto said platfornna discharge conveyor'b'elow the level and at a side of said platformbpposite said feed conveyor for receiving-units of acceptable weight discharged from *said platform, a downwardly inclined slide for directing units from sai'd'platform onto said discharge conveyor, means-at-a side of said platform away from said feed and discharge conveyo'rs for receiving units of unacceptableweight'ejected from said platform, a pair of 1 pusher plates each recipr'ocable toward and away from one'of-said discharge=conveyors and receiving means and normally positioned at sides of said platform, a fluid pressure motor for reciprocating each of said pusher plates, a solenoid actuated valve connected to each of said motors for controlling the direction of movement thereby of the associated 'pusher plate, photosensitive means responsive to the position of said pointer for selecting the pusher plate to be actuated in accordance with whether a unit on said platform is within or outside acceptable weight'limits, 'a-normally open starter switch, an angularly adjustable timing lug mounted on a roller of said feed conveyor'for closing said starter switch and initiating said selective actuation in timed relation to the arrival of eachof said pockets at the discharge end of said conveyor, and switchmeans engaged and closed by each of said pusher plates in the normal position thereof and opening on release therefrom for breaking both circuits to both of said pusher plates during the advance of one of said pusher plates.

ReferencesCitedin 'the'file of this patent UNITED STATES PATENTS 856,724 Richardson June 11, 1907 1,200,151 Tremaine Oct. 3, 1916 1,994,550 '-Watson Mar. 19, 1935 2,007,059 Meharg July 2, 1935 2,104,546 Pennell'et al Jan. 4, 1938 2,307,695 Mansbendel Jan. 5, 1943

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US856724 *Jan 16, 1906Jun 11, 1907Henry RichardsonWeighing and assorting apparatus.
US1200151 *Nov 27, 1908Oct 3, 1916Automatic Weighing Machine CompanyAutomatic weighing apparatus.
US1994550 *Jan 15, 1932Mar 19, 1935IbmScale
US2007059 *Feb 2, 1933Jul 2, 1935Hazel Atlas Glass CoAutomatic accepting and rejecting apparatus
US2104546 *Nov 27, 1934Jan 4, 1938IbmConveyer scale
US2307695 *Jul 5, 1940Jan 5, 1943Fred Goat Co IncWeight testing machine
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3009299 *Sep 2, 1958Nov 21, 1961Albert F Goetze IncAutomatic switching and storage conveyor
US3017026 *Jun 17, 1957Jan 16, 1962Fmc CorpWeight checking apparatus
US3272331 *Sep 24, 1963Sep 13, 1966Champion Papers IncWiener orienter
US4530435 *Nov 12, 1982Jul 23, 1985Apv Anderson Bros. Inc.Packaging apparatus for stick confections
US6252181Aug 4, 1999Jun 26, 2001Richard J. FallasMethod and apparatus for weighing a product
US6874615Jun 6, 2003Apr 5, 2005David M FallasConveyor chute
US7644558Oct 26, 2006Jan 12, 2010Fallas David MRobotic case packing system
EP1081048A1 Jul 4, 2000Mar 7, 2001TOPACK Verpackungstechnik GmbHApparatus and method for checking the completeness of a package
Classifications
U.S. Classification209/594, 209/596
International ClassificationB07C5/00, B07C5/20
Cooperative ClassificationB07C5/20
European ClassificationB07C5/20