US2675917A - Sorting device - Google Patents

Description

April 20,v 1954 v Filed Aug. 22, 1949 J; B. POWERS SORTING DEVICE 2 Sheets-Sheet 1 a 'i i INVENTOR JOHN B. POWERS.

BY I

ATTORNEYS.

April 20, 1954 Filed Aug. 22, 1949 J. B. POWERS SORTING DEVICE 2 Sheets-Sheet 2 INVENTOR, JOHN B. POWERS.

ATTORNEYS.

Patented Apr. 20, 1954 2,675,917 SORTING DEVICE John B. Powers, Davis, Calif; assignor to The Regents of The University of California, Berkeley, Calif., a corporation of California Application August 22, 1949, Serial No. 111,719

9 Claims.

This invention relates to apparatus arranged for feeding articles of varying sizes to an automatic sorter wherefrom the articles are finally discharged into outlet ducts, containers, hoppers or .the like after having been segregated as to size. As the invention is set forth it embodies a device wherein the control of sorting is accomplished through electronically operated mechanisms under the control of which articles of different sizes are segregated or sorted in'such a way as to provide uniform grading into size.

Many sorting and segregation operations are readily accomplished where the articles are of substantially spherical form. Articles of such configuration can be selected as to size and weight by directing them through sortingholes or apertures which are of progressively increasing size so that as the articles are moved they are sorted into generally like size characteristics. Units havin only a single axis of symmetry cannot be so readily graded because the major and minor axes may be of little difference in length, in some cases, whereas in other cases there may be considerable differences in length between the two axes. This fact thus substantially precludes sorting by the aforementioned sizing methods to provide reasonably accurate selections of like weight or cross-sectional area Where any considerable differences in article shape exist between different units. I

The invention thus to be described may be considered as one which is particularly adapted and suited for the sorting to size and weight of articles having generally different-length major and minor axes. I been tried in the past to provide sorting of this general type, but no reasonable degree of success has been attained as far as is known. The result is that the operations have, for the most part, been carried on by hand, with a result that much valuable time has been lost and the expense of sorting and segregating has become considerable. Furthermore, it has been found that the hand-sorting operation is very much subject to variances, even when carried on by experienced help. w

The apparatus herein to be described is such that the sorting may be'carried on eificiently and without damage to the article or product being sorted. In the form in which the invention will be described reference will be made tothe'sortingof citrus or other fruits having'asymmetri- Various arrangements have the illustration of a field of usage is merely to exemplify one form which has proven satisfactory in practice. In this form of the invention, provision will be made not only for sorting the articles as to size and Weight, but also the invention will incorporate features whereby damage, such as would result from permitting the articles to fall fromany considerable height, into the containers. crates or hoppers, can be avoided throughthe utilization of unique and novel features of what will herein be described. Furthermore, the invention in its preferred form, as will herein be set forth, is so constituted and arrangedthat the articles which are to be sorted and selected may be fed into the machine in random fashion and they will then automatically aline themselves into one appropriate and generally similar pattern from which measurements as to size, cross-section and shape readily may be obtained.

The present invention proposes apparatus which is so constituted and arranged that nonsymmetrical articles may be fed into the mechanism indiscriminately and arranged to be delivered from the apparatus to hoppers or containers after having been sorted precisely as to their size. In its preferred form, the apparatus of the invention comprises a conveyor mechanism, upon which the articles are placed initially in random fashion, and from which the articles are discharged by gravity after havingpreviously been accurately alined and positioned relative to one another. Upon discharge of each article from the conveyor system, it passes in such a way as to eclipse to varying degrees substantially parallelly directed light rays issuing from a light source, which rays are directed to be projected upon a photoelectric tube which serves to control sorting gate operating devices. The subject mat ter of the particular form of electron control apparatus is presented particularly in a concurrently filed U. S. patentapplication'Serial No.

and claimed' It is, of course, to be understood,

however, that the present application and'that related application above'named" are, enerally speaking, inter-related, so that reference may be had to the named pending application for a de- "scription of one suitable form of circuit arrange em i as ompl h ns m fl eransl 92mins of the sortinggates. P

.ers. finer that articles of one size only, or of one size In a preferred form of this apparatus several sorting or size-allocating gate members are provided for directing the articles into or throu h one or another of :a plurality of hoppers or ducts. One of these gate members is preferably arranged along the ridge of a gable-like structure with the ridge being approximately at the center of the path along which the articles to be sorted are discharged by gravity from the conveyor. The falling article, after passing through and eclipsin the light passing from the light source to operate the electronic control circuit, is adapted to strike this first sorting gate in a somewhat glancing fashion and to be directed thereby along one or another side of the gable. Arranged along the gable section and on either side of the sorting gate positioned along the gable ridge there have been provided a group of additional sorting gates. These gates are operated individually under the control of the output of the photoelectrically responsive control mechanism and circuit set forth in its details in the above named co-pending application. Closure or opening of thegate members determines into which of a plurality of ducts the articles are directed for segregation purposes so as then to be allocated into collection hoppers or contain- .The gatemembers operate in such a manwith'in reasonable limits of departure from a set standard, are to be directed along the selected paths.

Because the article fall by gravity into the path of the various segregating gates, and from there into 'the duct members, it is desirable prior to discharge of the article into the final hopper 'orcontainer to provide a suitable mechanism for decelerating each falling article so that no damage :or injury to :the article occurs by reason of the sorting operation itself. To this end, provision is made for catching each falling article in a hammock-like arrangement, from which the article .is subsequently discharged into an appropriate container or hopper.

Various forms of mechanisms for the carrying 'outof the aims and objectives of this invention may be provided, but it becomes one of :the primary'objects of the invention to provide ways and .means "by whicharticles fed into the mechanism in random fashion may, with a minimum of difficulty, be .segregated as to size. Other objects f the invention are the provision of relatively simple means :for segregating and sorting articlesof a similar characteriin such a way that the articles are effectively measured as to size and separated accordingly. Still other objects of the invention are the provision of sorting mechanisms whereby the objectives hereinabove stated are achieved without damage to the articles supplied to the mechanism. Otherobjectsof the invention, of course, are those of arranging a simple, efficient and yet, inexpensive structure to achieve'the ends hereinabove named.

The invention in one of itsjpreferred forms has been shown particularly by the accompanying drawings, wherein Fig. 1 illustrates in general elevation and in a rather schematic manner one form of the sorting mechanism; Fig. 2 is a view of the apparatus depicted in Fig. 1, looking from right to left in Fig. 1; Fig. 3 is a schematic view,

,partly in section, toshow the form of conveyor roller serving to aline the articles;supplied for sorting; Fig. 4 is a view lookingat Fig. 3 from right to left, and in order to depict-clearly the 5, comprised in parts (A), (B) and (C), and is to show more particularly and yet schematically the decelerating mechanism whereby articles, after having been sorted and segregated, are arrested in their motion and discharged into hop-- pers or container at substantially slow velocity and without damage to the article as a result of falling from the conveyor through substantially to the final hopper into which they are segregated. In this arrangement of Fig. 5, part (A) shows the hammock position immediately prior to the receipt of a falling article thereon; portion ()3) shows the flexure of the hammock upon receiving the article, and portion (C) shows the manner in which the article received by the hammock is subsequently discharged under the control of a rotating support member for freely holding one end of the hammock. Fig. 6 shows in part (A) the open gate with the rela ive shaping of the armature and pole pieces of the operating motor shaped to provide rapid gate opening and part (B) shows the relative shaping such that the high torque becomes efiectivein the gate open position. Fig. 7 illustrates the appropriate arrangement of the spring from the gate control arm to the two separate anchoring pins to provide the effect of varying strength springs for different gate operating conditions.

Referring now to the drawings for a further understanding of the invention, it will be seen that the apparatus comprises essentially four :main' components. First, is the form of the article orienting device, which provides for alining the articles on the conveyor from which they are discharged; secondly, there is the photoelectrically responsive measuring or gauging device which produces output currents measuring substantially precisely the size or cross-section of .the articles fed therethrough; thirdly, there is the segregating device, which allocates the articles into definite size classifications; and, -fourthly, there is the decelerating device serving to discharge the finally sorted article into collecting hoppers or containers.

Considering first the orientation of the articles .to be supplied, and assuming, for instance, that the invention from the above set forth standpoint as being directed to the sorting of citrus .fruits such .as the lemons conventionally represented by the numeral I, these articles are fed,

.for instance, by means of a belt feed, which is designated by the numeral 3, in such a Way that the articles thereby conveyed are caused to move to conveyor rollers generally designated at 5. The conveyor rollers are supported upon an axis orspindle-B in such a way as to roll across a guide track 1, rotating in the direction shown by the arrows. The axle or spindle 8 of each conveyor roller 5 is secured in an appropriate fashion to a drive chain mechanism 8, which is arranged to move in .the direction also shown by the arrow. The drive chain 8 feeds over a pair of sprockets 9 and l 9, theformer of which is supported in one end of "a support frame I 4 upon an axis or spindle l2 and is arranged to be driven. by means of a drive motor M connected to drive through a pulley and belt mechanism i5, or, alternatively, by way of .anysuitable chain or gearing drive, if desired. The sprocket 9 is appropriately keyed to the spindle .or axle 12, upon which it is supported, and so arranged that .on the opposite side of the frame H, as at H, a second drive sprocket may be arranged .to drive a second chain connected to move and drive the :rollers on the op configuration of the roller mechanism; and, Fig, yposite-sideyof the mechanism. The sprocket l0 matically. takes place.

. -is supported in the opposite end of the. frame support upon a spindle or axle member 16,

shown) corresponding in purpose to that shown at I and-serving as anzidler sprocket over which the chain mechanism is arranged to move.

The rollers are preferably surfaced with a tire, such as indicated at ill, to roll upon the track surface I and frictionally engage it. Between each of the rollers 5 is a concave cylindrical member 2| on to which the articles I from the belt feed 3 are adapted to fallfor orientation. Each concave cylinder 2| is preferably surfaced with a rather soft material covering which will notin- -jure the articles a they mcveand are transported the length of the conveyor system. As is shown in Fig. 1 of the drawings, the articles, such as the lemons I in feeding on to the conveyor from the belt feed 3 strike it initially in random fashion, and, as schematically represented, these articles, due to the rotation of the concave cylinders, are rotated and turn in such a Way as to orient themselves in the time between leaving on the articles 1 are intended to represent the ,long axis of the fruit and, as canbe seen from the schematic showing, the rotation of the con- .cave cylinders is such that with the rotation transferred to the article the alinement auto- The spacing and the surface of curvature of the rolls is such that the center of gravity of the supplied article continuously falls as the lemon is rotated about a vertical axis from the position in which the axis of the lemon is generally parallel to the conveyor at the time it first strikesthe rollers. This explains the reason why the lemons as they move along the conveyor tend to nest between the rollers with the'long axis transverse to the direction of conveyor travel, in that this position is the equilibrium position which the article tends to assume.

The concavityiof the rollers or cylinderstends to cause the article to arrange themselves in a substantially straight line in the passage from that end of the. conveyor whereat the articles are discharged from the conveyor belt 3 to that point whereat the article falls free of the conveyor proper. The rotating motion imparted to the articles as they traverse the rollers, of the con- ,veyor tends to insure that the established orientation will be maintained as the articles fall free of the conveyor along the path indicated at 25.

Experimentation has. shown that if the .pe-

5,;bemade 'of 'con'siderably'greater diameter than the concave cylinder members 2|, since theangular; velocityi of rotation of the rolls is inversely proportional to the diameter ofthe driving wheels at any givenspeediv Various mechanisms for driving the conveyor of course may be used, .butgit has been found that thatindicated ,1is,.reliably and sufficiently positive in its nature.; as well. as simple and-free from difliculty, s0 astomake; it desirable. in pref:-

erence to more complicated arrangements. While not shown for reasons of simplicity it is apparent that guide edges may be built up at the end of each roller to maintain the article in the belt, although this is usually not essential.

The next operation after the article has been segregated in such a way as to be oriented as to its axial position is to permit the article as it falls alongthe path designated at 25, to come withinthe substantially uniform intensity beam of parallelly directed light rays issuing from any suitable, source,,such as the lamp 26 and collimated by the convergent lens 21. The shadow cast by the falling article promptly reduces, eclipses, or even interrupts in some conditions, the light received by the objective 28 and directed into the conventionally represented photocell or phototube 29. The eclipsing of the light directed to the phototube serves to control (by an appropriate electronic relay circuit of the type described in the above-named concurrently filed copending application, for instance) the operation of the appropriate sorting gate or closure mechanisms. It can readily be established that the shadow cast by the falling article is a measure of its greatest cross-sectional area, and in this way it is possible to utilize the control measured in accordance with the degree to which the light to the phototube is eclipsed as a means whereby the falling article may be accurately and precisely sorted asto size.

'In cases where it is desired that even more precise sorting than originally occurred should be made, it is possible to rerun the operation by supplying to the sorting mechanism only those articles which have first been selected as to size. Then, the light beam from the source 26, as indicated, may be rotated to a position substantially at right angles to that represented by the drawing, and in this category the articles will then be subdivided on the basis. of the least cross-sectional area thereof, rather than the maximum cross-sectional area thereof, as was the basis of initial sorting. It is thus possible to segregate the articles on the basis of shape, as well'as on the basis of size, and it is to be understood that ineither arrangement the principles adopted and disclosed herein are equally applicable.

.Since the manner of control of the mechanism operated under the influence of the variations in light gauged by the falling article eclipsing the light beam have been set forth as the subject 7 matter of the separate and complete'patent application above named, further details thereof will notbe described'in this specification, other than to point out that the control introduced by the photoelectrically operated apparatus 29 is that one gate unit functions, for instance; to

segregate all articles below an intermediate average size into one group of sorters and articles of a size larger than the same intermediate paverage'size into another group of sorters. This gate mechanism is arranged to pivot and hinge fromaxis}! immediately above the ridge to wh ch two supporting gable members '32 and 33 are positioned.

While it has not been shown particularly in Fig. 1, the gate support framework is carried upon the gable members 32 and 33, and the gate itself is then pivoted along axis such as 31 formed in the gate support mechanism, not shown. It has been assumed that the gate member 34 which is pivoted on the axis 3| will divide the sorted articles into two groups larger and smaller than the mid-size chosen. Thus, if it be assumed that the gate 34 in its indicated position moves the falling articles to the left of the ridge and through the mechanisms supported upon gable 32, then it can be seen immediately that if an article larger'than one of midsize falls to interrupt the light beam between the source 26 and the phototube 29, the gate 34 will pivot about its axis 3| to the dotted line position 34, or, in other words, move counterclockwise, and the articles will then pass to the right side or through sorting gate mechanisms carried upon the gable 33. The details of the gate operating mechanisms will be presented in a separate concurrently-filed copending application Serial No. 111,720 of this inventor and entitled Gate Operating Motor, and now U. S. Patent No. 2,541,937, granted February 13, 1951. For the purpose of this application, suiiice it to say, therefore, that the various sorting gates, 34, 35, 36, 31 and 38, operate so as to select of various particular sizes from the articles supplied to the conveyor unit. Then, the selected articles are next fed through suitable ducts or passages into collecting hoppers or containers.

With the showing of five separate gate mechanisms it will be apparent that six separate size classifications may be obtained. This result is achieved, for instance, by so arranging the gate 34, as above mentioned, that it divides the classification between articles below a midsize and articles above a midsize arbitrarily selected. For instance, in the position shown and represented by the dot-dash line, the falling article traversing the path 25 from the conveyor mechanism will strike the left side of the gate 34 and be passed along the dotted path out through to the hopper or container immediately below the exit port 39 in that the gate mechanisms 35 and 36 are indicated as being closed. This position of the gate mechanism 34 likewise may be assumed to be its closed position or, in other words, that position which is maintained normally against the force of the control spring mechanism described particularly in connection with the showing in each of the aforesaid copending applications. If, however, it be assumed that an article which is of larger size than that which would be allocated to the hopper 39 falls along a path 25, then one of the gate devices 35 or 36 would arrange to open. If it be assumed that the gate 35 opens to select an article of the third size classification, then, of course, also the gate 36 would open, because current magnitude sufficient to operate the gate 35 would also operate the gate 36, but this factor is of no consequence in these considerations, in that an article falling and guided in its initial trajectory by the gate 34 would strike initially the gate 35, and thus be guided in accordance therewith.

One important factor in the operation of the device is the relative timing of the gates. Only one object can be passing through the apparatus at any one instant, and although the passage is rapid, a finite time does elapse'between the time 8 of passage of gate 34 and gate 36 or 33. The whole operation of the device depends upon gate 34 which must be ready to make its primary selection by the time the fruit has dropped a very few inches below the light-beam. This gate must therefore operate very rapidly to open, but since the next selection cannot be made until the fruit has had time to pass the final gate-36 or 38it may close more slowly. The later gates of the series need not open so rapidly, but if they do not they must close more quickly, since the length of their cycle of operation must be the same as that of gate 34.

A convenient type of motor for operating the gates has essentially the structure of the wellknown rotary relays. In the design of such devices it is known that the speed of operation can be controlled by shaping the pole-pieces. Opening is eifected electro-magnetically, closure by spring action.

If the field magnetomotive force is high, the maximum value of magnetic flux through the armature is determined by saturation of the armature material. 'If, under these conditions, the pole pieces are shaped so that the rate of change of flux with rotation in the initial position is high, there will be high torque and high acceleration, and opening will be rapid. The relatively low rate of change of flux near the end of the opening period will, however, result in relatively low torque at this point, and the opposing spring torque must be low to avoid stalling. The gate closes relatively slowly under the influence of this low spring torque. This arrangement is desirable for gate 34. These two conditions are indicated by Fig. 6 where, in part (A) the gate 34 is shown in open position, and where, in part (B) the gate is shown in closed position. However, in part (A) the pole pieces 6! and armature 63 are so shaped relative to each other that, as above stated, the initial rate of change of flux with rotation is high to provide high torque and acceleration of rapid opening.

If, however, the pole pieces are shaped so that maximum torque occurs in the open position, and, consequently, lower torque during the initial stages of opening, the opening will be slower. The high torque in the open position permits the use of a relatively strong return spring, and closure is therefore rapid. This arrangement is desirable for gates '36 and 38. The second condition is illustrated where a relatively low rate of change of fiux and resultant low torque occurs at the initial point in the operation. The high torque is effective in the open position of the gate 34.

As above explained, where the rate of change of flux is low near the end of the opening period and relatively low torque is required, as in the condition for part (A) of Fig. 6, a relatively weak spring pressure as exerted by a spring 65 in Fig. '7 is needed. The spring pressure under these conditions must be relatively weak at the beginning of the closing period, since the time required for closing is relatively great. With the pole piece andarmature shape as in part (B) of Fig. 6, the reverse is true. By connecting the spring 65 at one end to a pin 61 attached to an arm 69 which is in turn secured to the armature (not shown in Fig. 7), and the other end of the spring-being attached to pins such as H and l I for instance, various spring tensions may be had from the same apparatus. In the position at which the spring 65 is shown in Fig. 7, the movement or the arm 69 about the armature shaft does not' chan'ge greatly between a rimy 6 m and a fully closed position of the gate. Hence, the torque 'on' the arm 69 produced by the spring 65 will increase continuously with the opening of the gate. By moving the end of the spring 65 from the pin H to the pin '1! the arm in the open' gate position is only a fraction of that in the closed position; hence the torque due to the spring may be caused to decrease as the gate opens. In this'way the eflect of varying-strength springs is readily attainable.

Various forms of gate motors are available, and the particular form employed is no part of this invention. The principles above mentioned are applicable to nearly all types, however, and the important point in connection with the present tion by one of the gate members, it passes through a duct such as that represented at 45, in order to reach the appropriate hopper, which hoppers may be designated, for instance, by the numerals 39 through for the assumed six different sizes of classification. If now the article to be sorted is one of a size larger than the assumed midsize, the'gateg34 will move under the control of the current output and the relay mechanism not herein described, operated from the phototube 29, so that the gate position 34' is assumed. Then thefalling. article will traverse apath to the right of the gate member 34, and in the absence of any'operation of either gate 31 or 38 the size classification with which the hopper 44 is associated. If, however, the largest size article to be selected passes through the light beam path, then itwill be observed that the. gate 3'! will open, aswell as gates 34 and 38, and the fallingarticle will beguided to the right of the gate "34' and into the hopper '42, to which it is quires considerable kinetic energy. Part of this is dissipated by glancing impact with the'sorting gates, and the latter may be of cloth loosely stretched over skeleton frames so that such impact will do no harm. The energy absorbed is a relatively small proportion of the'total, however,

and for this reason it is'desirable to protect the article from damage-to itself or to those other articles with which it comes in contact in the hopper. To this end, the invention makes provision for decelerating the acquired motion, and

accordingly, at the end of each discharge duct 45 -priorto discharge of the articles into one of the associatedhopper mechanisms 39 through This ham-- 44 there is a hammock member 50.

mockmembe-r has for its purpose/that of de-* celerating the fallingarticle and dissipating the kinetic energy acquired by it in its fall from the conveyor andyetwithout in anyway damaging or bruising-thearticle itself. The hammockis preferably constructed from sponge rubber-or;

other soft material which has a relatively low elastic," modulus and which has relatively high mechanical hysteresis.

This hammock is attached rigidly at its-upper end 5| to the framework of the sorting apparatus and at its lower endfrely rests, as at the point 52, upon a nonrigid s'upport such as the hexagonally-shaped member 53'which may be rotated, as indicated. The falling article, indicated at Fig. 2 as traversing'the dot-dash path, when striking the hammock has its kinetic energy transferred into energy of flexure of the hammock, as is shown particularly by portion (B) of Fig. 5. This is accomplished without transferring any appreciable amount of energy to the article itself. By reason of the choice of the resilient soft material for the hammock structure, there is a relatively low coefiicient of restitution of the hammock itself, and consequently the low value of surface transfer of energy to the article is brought about. The extremely high internal hysteresis of the hammock prevents the falling article from rebounding from the hammock after striking it by absorbing some of the kinetic energy of the falling body, although it will be appreciated that a certain portion of the energy is also absorbed in the frictional losses that occur when the resilient hammock member is flexed and drawn over the non-rigid support or roller 53. roller such as the hexagonal member 53 shown serves to straighten the hammock after impact so that the article held or supported thereon may be discharged by gravity into the desired hopper. The roller 53 might be of shapes other thanthe suggested hexagonal (e. g., a cylinder), but for many reasons the hexagonal shape is preferred, and especially because the surface contour is such that in straightening of the hammock 50 the article tends more easily to discharge. Various mechanisms for rotating the roller may be utilized, but for illustrative purposes the drive motor 55 and the belt drive 55 have been found satisfactory to achieve the objectives. The arrangement of the components herein is such that one of the hammock members 7 fall gravitationally into the'hopperor container with little or no kinetic energy in excess of that which they would derive by reason of being manually placed into the hoppers.

Having now described the invention, what is claimed is:

1. An apparatus for sorting articles as to size wherein the articles are fed along a continuously moving'conveyor having a plurality of concave conveyor rollers for alining the articles during :advance motion along the conveyor comprising a plurality of duct" members'to connect with stora e hoppers and a plurality of closure gates for directing the articles into individual ducts in accordance with article size, said gates being arone or. the other side of the gable ridge with variances in article size on either side of a selected average; photoelectric means positioned in the region wherein the articles move by gravitational force for-producing current controlled in proportion to article'size, means for releasing the individual gate members in accordance with the magnitude of the produced current to allocate thearticles to the ducts related 'to the article size, a motor associated with each gate to control-the rate of opening and closing thereof, the' The rotating motors having different starting means connected to each gate with the initial 7 force effective to close the gates being greater in proportion to the distance of the controlledgate from the conveyor.

2. An apparatus for sorting articles as to size wherein the articles are fed along a continuously movin conveyor having a plurality of concave conveyor rollers for alining the articles during advance motion along the conveyor and to dis charge the alined articles by gravity at the end of the conveyor comprising a plurality of; duct members to connect with storage hoppers and a plurality of closure gates for directing the articles into individual ducts in accordance with art1- cle size, said gates being arranged in able fashion with the gable ridge substantially inthe path along which the articles fall by gravitational force after discharge from the conveyor, a gate positioned. substantially at the gable ridge to direct the fa1ling articles to one or the other side of the gable ridge with variances in article size on either side of a selected average, photoelectric means positioned in the region wherein the articles move by gravitational force for producing a current controlled in proportion to article size, motor means for operatin the individual gate members in accordance with the magnitude of the produced current to allocate the articles to the ducts related to the article size, a gate member positioned at the gable ridge to guide articles discharged from the conveyor along either side of the gabl dependent upon article size, the motors for controlling the individual gates having difierent starting torques of which the magnitude decreases from one to another in accordance with the remoteness of the thereby controlled gate from the article conveyor, with the gates nearer the conveyor opening more rapidly than gates remote therefrom, and resilient closure control means connected with each ate and motor with the individual force effective to close the gates being initiated with an interruption of operating current to the motors and being greater in proportion to the distance of the controlled gate from the conveyor.

3. An apparatus for sorting articles as to size wherein the articles are fed along a continuously moving conveyor having a plurality of concave conveyor rollers for alining the articles during advance motion along the conveyor and to discharge the articles so that they fall gravitationally from the end of the conveyor comprising a plurality of duct members to connect with storage hoppers and a plurality of closure gates for directing the articles into individual ducts in accordance with article size, said gates being arranged in gable fashion with the gable ridge substantially in the path along which the articles fall by gravitational force after discharge from the conveyor, a gate member positioned at the gable ridge to guide articles discharged from the conveyor along either side of the gable dependent upon article size, and photoelectrically responsive means interposed between the end of the conveyor and the gable ridge to control the opening and closing of individual gate members in accordance with the size of the fallin article, and a decelerating device supported at approximately the end of each duct to receive the articles and for subsequently gravitationally discharging them at approximately zero initial velocity.

4. A decelerating device comprising a hammock formed of a soft material having a low elastic modulus and a high mechanical hysteresis, a rigid support for fastening one end of. th hammock and a rotatable and movable non-rigid support upon which the opposite end of the hammock is rested at a point below that whereat the hammock is rigidly supported so that after receiving articles tending to flex it the hammock is straightened and articles thereon are gravitationally discharged.

5. A decelerating device comprising an elongated resilient element havin a relatively low elastic modulus and relatively high mechanical hysteresis, means to anchor rigidly the element at one end only, a non-rigid support for frictionally holding the other end of the resilient element so that articles falling upon the resilient element in the region between the rigid and non rigid supports have their kinetic energy transformed into energy to flex the resilient element and the resilient element is slidably supported relative to the non-rigid support so that the energy is partially absorbed frictionally by the resilient element slidin relative to the non-rigid support and the high mechanical hysteresis of the resilient element prevents prompt article rebound therefrom.

6. A decelerating device comprising an elongated resilient element having a relatively low elastic modulus and relatively high mechanical hysteresis, means to anchor rigidly the element at one end only, a non-rigid support for fric tionally holding the other end of the resilient element so that articles falling upon the resilient element in the region between the rigid and nonrigid supports have their kinetic energy transformed into energy to flex the resilient element and the resilient element is slidably supported relative to the non-rigid support so that the energy is partially absorbed frictionally by the resilient element sliding relative to the non-rigid support and the high mechanical hysteresis of the resilient element prevents prompt article rebound therefrom; and means for rotatin the non-rigid support element so as to draw the resilient element into substantially its original shape subsequent to the receipt of the article thereon, and thereby to aid in the discharge of the supported article from the resilient element.

'7. A decelerating devic comprising an elongated resilient element having a relatively low elastic modulus and a relatively high mechanical hysteresis, means to anchor rigidly the element at one end only, a rotatable device for freely supporting the said resilient element between its point of anchor and its opposite end so that articles falling upon the element in the region between the anchored end and the rotatable device have their kinetic energy transformed into energy to flex the resilient element, with the high mechanical hysteresis of the element preventing article rebound therefrom, and subsequently, due to rotation of the rotatable device, the element is frictionally drawn to substantially its initial state for discharging articles therefrom.

8. A decelerating device comprising a hammock of soft material having a low elastic modulous and high mechanical hysteresis, a rigid support for fastening one end only of the hammock in cantilever fashion with the opposite end free of fixed support, a rotatable element 10- cated below the point of rigid support and between the point of rigid support and the free end of the hammock upon which the hammock is adapted to be rested free of any fixed enga ment so that after articles are caused to fall upon the hammock in the region between the point of rigid support and the rotatable element so that the article weight tends to flex the hammock the said hammock is straightened by reason of its frictional engagement with the rotatable element so that articles held thereon are gravitationally discharged.

9. A decelerating device comprising an article carrying element formed of sponge rubber, a rigid anchoring means for fastening one end only of the article carrying element, a second support point for the article carrying element comprising an element having polygonal periphery which is supported for rotational movement and is located between the anchoring means of the article carrying element and its free end and upon which the article carrying element is adapted to be rested without securement so that after receiving articles in the region between the r0- tatable element and the anchoring means the weight of which articles tends to flex the article carrying element the said element is straightened by rotation of the rotatable member and its straight sides so that articles carried thereon are gravitationally discharged.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 697,360 Pettit Apr. 8, 1902 1,482,198 Lebeis Jan. 29, 1924 1,538,122 Kurtz May 19, 1925 1,722,751 Jones July 30, 1929 1,927,217 Price Sept. 19, 1933 1,954,164 Wyland Apr. 10, 1934 1,958,322 Symington May 8, 1934 2,019,138 Kliesrath Oct. 29, 1935 2,045,769 Geficken June 30, 1936 2,112,259 Wyland Mar. 29, 1938 2,229,638 Chamberlin Jan. 28, 1941 2,442,521 White June 1, 1948 FOREIGN PATENTS Number Country Date 52,172 Norway Sept. 8, 1930

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